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1

Luque-Almagro, Víctor M., Andrew J. Gates, Conrado Moreno-Vivián, Stuart J. Ferguson, David J. Richardson, and M. Dolores Roldán. "Bacterial nitrate assimilation: gene distribution and regulation." Biochemical Society Transactions 39, no. 6 (November 21, 2011): 1838–43. http://dx.doi.org/10.1042/bst20110688.

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In the context of the global nitrogen cycle, the importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognized. In contrast, the utilization of nitrate by heterotrophic bacteria has historically received less attention because the primary role of these organisms has classically been considered to be the decomposition and mineralization of dissolved and particulate organic nitrogen. In the pre-genome sequence era, it was known that some, but not all, heterotrophic bacteria were capable of growth on nitrate as a sole nitrogen source. However, examination of currently available prokaryotic genome sequences suggests that assimilatory nitrate reductase (Nas) systems are widespread phylogenetically in bacterial and archaeal heterotrophs. Until now, regulation of nitrate assimilation has been mainly studied in cyanobacteria. In contrast, in heterotrophic bacterial strains, the study of nitrate assimilation regulation has been limited to Rhodobacter capsulatus, Klebsiella oxytoca, Azotobacter vinelandii and Bacillus subtilis. In Gram-negative bacteria, the nas genes are subjected to dual control: ammonia repression by the general nitrogen regulatory (Ntr) system and specific nitrate or nitrite induction. The Ntr system is widely distributed in bacteria, whereas the nitrate/nitrite-specific control is variable depending on the organism.
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2

Tanaka, T., F. Rassoulzadegan, and T. F. Thingstad. "Analyzing the trophic link between the mesopelagic microbial loop and zooplankton from observed depth profiles of bacteria and protozoa." Biogeosciences 2, no. 1 (February 1, 2005): 9–13. http://dx.doi.org/10.5194/bg-2-9-2005.

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Abstract. It is widely recognized that organic carbon exported to the ocean aphotic layer is significantly consumed by heterotrophic organisms such as bacteria and zooplankton in the mesopelagic layer. However, very little is known for the trophic link between bacteria and zooplankton or the function of the microbial loop in this layer. In the northwestern Mediterranean, recent studies have shown that viruses, bacteria, heterotrophic nanoflagellates, and ciliates distribute down to 2000 m with group-specific depth-dependent decreases, and that bacterial production decreases with depth down to 1000 m. Here we show that such data can be analyzed using a simple steady-state food chain model to quantify the carbon flow from bacteria to zooplankton over the mesopelagic layer. The model indicates that bacterial mortality by viruses is similar to or 1.5 times greater than that by heterotrophic nanoflagellates, and that heterotrophic nanoflagellates transfer little of bacterial production to higher trophic levels.
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3

Tanaka, T., F. Rassoulzadegan, and T. F. Thingstad. "Quantifying the structure of the mesopelagic microbial loop from observed depth profiles of bacteria and protozoa." Biogeosciences Discussions 1, no. 1 (August 19, 2004): 413–28. http://dx.doi.org/10.5194/bgd-1-413-2004.

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Abstract. t is widely recognized that organic carbon exported to the ocean aphotic layer is significantly consumed by heterotrophic organisms such as bacteria and zooplankton in the mesopelagic layer. However, very little is known for the trophic link between bacteria and zooplankton or the structure of the microbial loop in this layer. In the northwestern Mediterranean, recent studies have shown that viruses, bacteria, heterotrophic nanoflagellates, and ciliates distribute down to 2000 m with group-specific depth-dependent decreases, and that bacterial production decreases with depth down to 1000 m. Here we show that such data can be analyzed using a simple steady-state food chain model to quantify the carbon flow from bacteria to zooplankton over the mesopelagic layer. The model indicates that a similar amount of bacterial production is allocated to viruses and heterotrophic nanoflagellates, and that heterotrophic nanoflagellates are the important remineralizers.
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4

Shanthi, T. R., Mohammed Hatha, and T. R. Satyakeerthy. "A Study on the Diversity of Pesticide-Resistant Bacterial Population from Different Agricultural Fields of Manjoor." Nature Environment and Pollution Technology 21, no. 3 (September 1, 2022): 1209–16. http://dx.doi.org/10.46488/nept.2022.v21i03.026.

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The regular usage of pesticides in agricultural fields results in the development of a pesticide-resistant microbial population. Vegetable cultivation is a common practice in the agricultural growing areas of Manjoor, Kerala. The present study was envisaged to understand the resistance of microorganisms to different types and doses of pesticides. The study revealed that heterotrophic bacteria are capable of resisting lower concentrations (0.01 and 0.001%) of the pesticides lindane and methyl parathion while a higher concentration of carbaryl (0.1%) could also be tolerated. In the soil sample where there was no prior addition of pesticides, the heterotrophic bacteria could only tolerate very low concentrations of pesticides The results of mean pesticide-resistant bacterial load when compared to normal Total Heterotrophic Bacteria (THB) of soils indicate that pesticides exhibited an inhibitory effect on the heterotrophic bacteria of soils collected from different agricultural fields and the pesticide-resistant bacterial load was lower than normal THB.
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5

Satoh, Hiroo, Kimio Fukami, Kentaroo Watanabe, and Eiji Takahashi. "Seasonal changes in heterotrophic bacteria under fast ice near Syowa station, Antarctica." Canadian Journal of Microbiology 35, no. 2 (February 1, 1989): 329–33. http://dx.doi.org/10.1139/m89-050.

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Seasonal changes in the number of heterotrophic bacteria and the species composition of their communities were investigated in the fast ice area of Syowa station (69°00′S, 39°35′E), from May 1983 to January 1984. Numbers of heterotrophic bacteria under the fast ice began to increase in October and the maximum number of colony-forming units/mL (2.4 × 102) were obtained in late December. The changes in bacterial numbers coincided well with those of particulate organic carbon, suggesting that the growth of heterotrophic bacteria depends on the supply of particulate organic carbon from ice algal assemblages which grow rapidly at the bottom of sea ice during the austral spring. Vibrionaceans in the communities in September accounted for as much as 35% of the isolates, whereas in December, they were not detected at all. These results indicate that there is a seasonal succession in the bacterial communities between September and December.Key words: heterotrophic bacteria, vibrionaceans, fast ice, Antarctica.
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6

Sala, Maria Montserrat, and Hans Güde. "Ectoenzymatic activities and heterotrophic bacteria decomposing detritus." Archiv für Hydrobiologie 160, no. 3 (July 12, 2004): 289–303. http://dx.doi.org/10.1127/0003-9136/2004/0160-0289.

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7

Childress, H., B. Sullivan, J. Kaur, and R. Karthikeyan. "Effects of ultraviolet light disinfection on tetracycline-resistant bacteria in wastewater effluents." Journal of Water and Health 12, no. 3 (December 24, 2013): 404–9. http://dx.doi.org/10.2166/wh.2013.257.

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The ubiquitous use of antibiotics has led to an increasing number of antibiotic-resistant bacterial strains, including strains that are multidrug-resistant, pathogenic, or both. There is also evidence to suggest that antibiotic resistance genes (ARGs) spread to the environment, humans, and animals through wastewater effluents. The overall objective of this study was to investigate the effect of ultraviolet (UV) light disinfection on antibiotic-resistant bacteria. Wastewater effluent samples from a wastewater treatment plant (WWTP) in Texas were evaluated for differences in tetracycline-resistant bacteria before and after UV treatment. The effects of photoreactivation or dark repair on the reactivation of bacteria present in WWTP effluent after UV disinfection were also examined. Culture-based methods were used to characterize viable heterotrophic, tetracycline-resistant heterotrophic, Escherichia coli, and tetracycline-resistant E. coli bacteria present before and after UV treatment. UV disinfection was found to be as effective at reducing concentrations of resistant heterotrophs and E. coli, as it was at reducing total bacterial concentrations. The lowest survival ratio following UV disinfection was observed in tetracycline-resistant E. coli showing particular susceptibility to UV treatment. Photoreactivation and dark repair rates were found to be comparable to each other for all bacterial populations.
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8

Pernie, Gwenyth Laird, Donald Scavia, Michael L. Pace, and Hunter J. Carrick. "Micrograzer Impact and Substrate Limitation of Bacterioplankton in Lake Michigan." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 9 (September 1, 1990): 1836–41. http://dx.doi.org/10.1139/f90-209.

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We estimated Lake Michigan epilimnetic heterotrophic bacterial loss rates, predator size, and substrate limitation in 1986 and 1987. The bacterial growth rates were always enhanced by organic substrate additions indicating that bacterial growth is limited, to some degree, by substrate availablility. In this study we obtained loss rates and intrinsic growth rates each between 0.32 and 1.45 d−1. The grazers were predominantly picoplankton-size organisms, presumably heterotrophic flagellates. Using radiolabeled bacteria, only a small percentage (2–3%) of bacterial cells were incorporated into larger size fractions after 24 h. These results indicate that during our experiments heterotrophic bacteria were not a direct, significant, carbon source for the upper trophic levels.
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9

Rittmann, Bruce E., John M. Regan, and David A. Stahl. "Nitrification as a source of soluble organic substrate in biological treatment." Water Science and Technology 30, no. 6 (September 1, 1994): 1–8. http://dx.doi.org/10.2166/wst.1994.0247.

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In complex, multispecies populations, exchange of substrates can be an important beneficial interaction. Prior experimental and theoretical work has led to the hypothesis that the formation of soluble microbial products (SMP) by nitrifying bacteria can provide a supplementary organic substrate for heterotrophic bacteria, thereby augmenting their accumulation and stability, especially when inputs of organic substrates are low. In this study, chemostat experiments carried out with a NO2−-oxidizing strain (Nitrobacter sp.) and an NH4+-oxidizing strain (Nitrosomonas europaea) demonstrated that both nitrifiers produce SMP that can support heterotrophic bacteria. The first evidence was the presence of significant concentrations of soluble COD in the chemostat effluent, even though the influent was free of organic compounds. Second, a small heterotrophic population was maintained, apparently through utilization of the nitrifier-produced SMP. A preliminary kinetic analysis suggested that SMP kinetic parameters can be adapted from parameters measured for heterotrophs.
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10

Setiaji, Jarod, Feli Feliatra, Hilwan Yuda Teruna, Iesje Lukistyowati, Indra Suharman, Zainal Abidin Muchlisin, and Teuku Iskandar Johan. "Antibacterial activity in secondary metabolite extracts of heterotrophic bacteria against Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa." F1000Research 9 (December 21, 2020): 1491. http://dx.doi.org/10.12688/f1000research.26215.1.

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Background: Disease causing bacteria such as Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa present a problem for fish farming. Treatment to remove them are generally carried out using antibiotics which have side effects on fish, the environment and humans. However, the use of antibacterial compounds derived from heterotrophic bacteria serve as a good alternative for antibiotics. Therefore, this study aimed to explore antibacterial activity in the secondary metabolite extracts of heterotrophic bacteria against Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa. Methods: Heterotrophic bacteria namely Bacillus sp. JS04 MT102913.1, Bacillus toyonensis JS08 MT102920.1, Bacillus cereus JS10 MT102922.1, Bacillus sp. JS11 MT102923.1, Pseudoalteromonas sp. JS19 MT102924.1, Bacillus cereus JS22 MT102926.1, and Bacillus sp. strain JS25 MT102927.1 were used in this study. The sequences of these bacteria have been deposited and are available from NCBI GenBank. Each heterotrophic bacterium was cultured on 6L nutrient broth for 8 days, and extracts produced using ethyl acetate to obtain their secondary metabolites. These extracts were tested for their phytochemical contents using FT-IR and also tested for their inhibitory property in pathogenic bacteria by agar diffusion method. Results: Phytochemical test results showed that the seven heterotrophic bacterial isolates produced terpenoid compounds. Based on the inhibitory test, the secondary metabolite extracts from Bacillus sp strain JS04 had the highest inhibitory effect on the growth of pathogenic bacteria namely, V. alginolyticus (17.5 mm), A. hydrophila (16.8 mm), and P. aeruginosa (17.3 mm). Conclusion: It was concluded that the secondary metabolite extracts of heterotrophic bacteria inhibit the growth of V. alginolyticus, A. hydrophila, and P. aeruginosa.
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11

Payment, Pierre. "Bacterial colonization of domestic reverse-osmosis water filtration units." Canadian Journal of Microbiology 35, no. 11 (November 1, 1989): 1065–67. http://dx.doi.org/10.1139/m89-178.

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We have analyzed the bacterial content of water from the reservoirs of 300 reverse-osmosis units installed in households. The heterotrophic plate counts on R2A medium (20 and 35 °C) ranged from 0 to 107 colony forming units per millilitre (cfu/mL). Most reservoirs contained water with bacterial counts between 104 and 105 cfu/mL. The bacteria identified were Pseudomonas (not aeruginosa), Alcaligenes or Moraxella, Acinetobacter, Flavobacterium, and Chromobacterium. This report emphasizes the importance of bacterial colonization by heterotrophic bacteria in water reservoirs from domestic reverse-osmosis units.Key words: drinking water, bacteria, reverse-osmosis filter, regrowth.
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12

SUI SIEN LEONG, HADI HAMLI, ERRA FAZIRA ABDUL RAHIM, and SUHAILI MUSTAFA. "Prevalence and Diversity of Antibiotic Resistance Heterotrophic Bacteria Found Along the Bintulu Rivers, Sarawak." Borneo Journal of Resource Science and Technology 13, no. 2 (December 24, 2023): 32–41. http://dx.doi.org/10.33736/bjrst.5450.2023.

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The study aims (1) to isolate and characterise the heterotrophic bacteria from different rivers in Bintulu, Sarawak, (2) to investigate the hygienic condition of the rivers through faecal coliforms and (3) to determine the antibiotic resistance among the heterotrophic bacteria isolates. A total of 100 heterotrophic bacteria strains were identified from rivers of Bintulu, Sarawak. The characterisation of bacteria was performed using (GTG)5 fingerprinting to investigate their genetic distribution diversity and 16S rRNA gene sequencing. Microbiological variables tested including total viable count, coliform count, Escherichia coli confirmation test. Antibiotic susceptibility test was performed against 10 antibiotics. Sample collected from Sungai Teknik showed higher mean bacterial population size (log 4.48 ± 0.00 CFU/mL). Sungai Sibiu, Waterfront and Sungai Plan revealed the highest most probable number (MPN) index (>1,600 per mL). Each dendrogram showed 3 to 7 clusters of bacteria groups confirmed as Enterobacter spp. (40%), Acinetobacter spp. (13%), Bacillus spp. (13%), Klebsiella spp. (13%), Staphylococcus spp. (7%), Chromobacterium spp. (7%) and Citrobacter spp. (7%). All the heterotrophic bacteria isolated showed high resistance against ciprofloxacin (63.70 ± 33.40%), piperacillin (58.10 ± 31.37%), aztreonam (48.40 ± 30.95%) and more susceptible to tetracycline (3.30 ± 10.44%). Our findings highlight the multiple antibiotics resistance and microbiological analysis of heterotrophic bacteria found in polluted river water. The preservation of the river water is vital as hydrologic purposes, sustain the microbial composition, ecological integrity of the river.
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13

Nicomrat, Duongruitai, and Siriphatrc Chamutpong. "Effects of Silver Nanoparticles on Heterotrophic Bacterial Community Inhabiting the Anoxic Paddy Soil of Flooded Rice Microcosms." Applied Mechanics and Materials 866 (June 2017): 152–55. http://dx.doi.org/10.4028/www.scientific.net/amm.866.152.

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Although silver nanoparticles (AgNPs) have been applied more in our daily life. They are well known for their antimicrobial activities against a wide range of organisms but more concerns on the negative effects of AgNP products contaminated to the environment especially on most microorganism niches related to nutrient cycling in ecosystem. In the study, research was done to in understand the effects of AgNPs on heterotrophic bacterial populations in rice paddy soil. Both culturable N2-fixing bacteria and common heterotrophic bacteria could adapt themselves to AgNPs at low concentration (less than 50 ppm). However, more distinct reduction in N2-fixing bacteria against AgNPs were detected than heterotrophic bacterial niches at least 100 ppm AgNPs . These evidences indicated AgNPs at high concentration had significant adverse effects on the diverse microbial consortiums as well as rice seedlings.
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14

Kindaichi, Tomonori, Tsukasa Ito, and Satoshi Okabe. "Ecophysiological Interaction between Nitrifying Bacteria and Heterotrophic Bacteria in Autotrophic Nitrifying Biofilms as Determined by Microautoradiography-Fluorescence In Situ Hybridization." Applied and Environmental Microbiology 70, no. 3 (March 2004): 1641–50. http://dx.doi.org/10.1128/aem.70.3.1641-1650.2004.

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ABSTRACT Ecophysiological interactions between the community members (i.e., nitrifiers and heterotrophic bacteria) in a carbon-limited autotrophic nitrifying biofilm fed only NH4 + as an energy source were investigated by using a full-cycle 16S rRNA approach followed by microautoradiography (MAR)-fluorescence in situ hybridization (FISH). Phylogenetic differentiation (identification) of heterotrophic bacteria was performed by 16S rRNA gene sequence analysis, and FISH probes were designed to determine the community structure and the spatial organization (i.e., niche differentiation) in the biofilm. FISH analysis showed that this autotrophic nitrifying biofilm was composed of 50% nitrifying bacteria (ammonia-oxidizing bacteria [AOB] and nitrite-oxidizing bacteria [NOB]) and 50% heterotrophic bacteria, and the distribution was as follows: members of the alpha subclass of the class Proteobacteria (α-Proteobacteria), 23%; γ-Proteobacteria, 13%; green nonsulfur bacteria (GNSB), 9%; Cytophaga-Flavobacterium-Bacteroides (CFB) division, 2%; and unidentified (organisms that could not be hybridized with any probe except EUB338), 3%. These results indicated that a pair of nitrifiers (AOB and NOB) supported a heterotrophic bacterium via production of soluble microbial products (SMP). MAR-FISH revealed that the heterotrophic bacterial community was composed of bacteria that were phylogenetically and metabolically diverse and to some extent metabolically redundant, which ensured the stability of the ecosystem as a biofilm. α- and γ-Proteobacteria dominated the utilization of [14C]acetic acid and 14C-amino acids in this biofilm. Despite their low abundance (ca. 2%) in the biofilm community, members of the CFB cluster accounted for the largest fraction (ca. 64%) of the bacterial community consuming N-acetyl-d-[1-14C]glucosamine (NAG). The GNSB accounted for 9% of the 14C-amino acid-consuming bacteria and 27% of the [14C]NAG-consuming bacteria but did not utilize [14C]acetic acid. Bacteria classified in the unidentified group accounted for 6% of the total heterotrophic bacteria and could utilize all organic substrates, including NAG. This showed that there was an efficient food web (carbon metabolism) in the autotrophic nitrifying biofilm community, which ensured maximum utilization of SMP produced by nitrifiers and prevented buildup of metabolites or waste materials of nitrifiers to significant levels.
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Lee, Choon Weng, and Chui Wei Bong. "Bacterial abundance and production, and their relation to primary production in tropical coastal waters of Peninsular Malaysia." Marine and Freshwater Research 59, no. 1 (2008): 10. http://dx.doi.org/10.1071/mf07099.

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In the present study, the relationship between bacteria and phytoplankton in tropical coastal waters was investigated. The bacterial abundance, bacterial production, chlorophyll a concentration and net primary production were measured at several locations in the coastal waters of Peninsular Malaysia. Chlorophyll a concentration ranged from 0.40 to 32.81 μg L–1, whereas bacterial abundance ranged from 0.1 to 97.5 × 106 cells mL–1. Net primary production ranged from 8.49 to 55.95 μg C L–1 h–1, whereas bacterial production ranged from 0.17 to 70.66 μg C L–1 h–1. In the present study, the carbon conversion factor used to convert bacterial production (cells mL–1 h–1) into carbon units ranged from 10 to 32.8 fg C cell–1, and was estimated from the bacterial size distribution measured at each location. Both phototrophic and heterotrophic biomass (bacteria–chlorophyll a) and activity (bacterial production–net primary production) were significantly correlated, although their correlation coefficients (r2) were relatively low (r2 = 0.188 and r2 = 0.218 respectively). Linear regression analyses provided the following equations to represent the relationship between: bacteria and chlorophyll a (Chl a), log Bacteria = 0.413 log Chl a + 6.057 (P = 0.003); and between bacterial production (BP) and net primary production (NPP), log BP = 0.896 log NPP – 0.394 (P = 0.004), which fitted with published results well. Comparison of annual carbon fluxes confirmed the prevalence of net heterotrophy in these coastal waters, and together with the low correlation coefficients, suggested the role of allochthonous organic matter in supporting heterotrophic activity.
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Okabe, Satoshi, Tomonori Kindaichi, and Tsukasa Ito. "Fate of 14C-Labeled Microbial Products Derived from Nitrifying Bacteria in Autotrophic Nitrifying Biofilms." Applied and Environmental Microbiology 71, no. 7 (July 2005): 3987–94. http://dx.doi.org/10.1128/aem.71.7.3987-3994.2005.

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ABSTRACT The cross-feeding of microbial products derived from 14C-labeled nitrifying bacteria to heterotrophic bacteria coexisting in an autotrophic nitrifying biofilm was quantitatively analyzed by using microautoradiography combined with fluorescence in situ hybridization (MAR-FISH). After only nitrifying bacteria were labeled with [14C]bicarbonate, biofilm samples were incubated with and without NH4 + as a sole energy source for 10 days. The transfer of 14C originally incorporated into nitrifying bacterial cells to heterotrophic bacteria was monitored with time by using MAR-FISH. The MAR-FISH analysis revealed that most phylogenetic groups of heterotrophic bacteria except the β-Proteobacteria showed significant uptake of 14C-labeled microbial products. In particular, the members of the Chloroflexi were strongly MAR positive in the culture without NH4 + addition, in which nitrifying bacteria tended to decay. This indicated that the members of the Chloroflexi preferentially utilized microbial products derived from mainly biomass decay. On the other hand, the members of the Cytophaga-Flavobacterium cluster gradually utilized 14C-labeled products in the culture with NH4 + addition in which nitrifying bacteria grew. This result suggested that these bacteria preferentially utilized substrate utilization-associated products of nitrifying bacteria and/or secondary metabolites of 14C-labeled structural cell components. Our results clearly demonstrated that the coexisting heterotrophic bacteria efficiently degraded and utilized dead biomass and metabolites of nitrifying bacteria, which consequently prevented accumulation of organic waste products in the biofilm.
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17

JANA, T. K., R. D. BANERJEE, SUSMITA LAHIRI, and B. B. JANA. "Management induced changes of antibiotic resistant strains of heterotrophic bacteria in shrimp farming ponds." Indian Journal of Animal Sciences 84, no. 3 (March 7, 2014): 323–28. http://dx.doi.org/10.56093/ijans.v84i3.38721.

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Antibiotic resistant strains of heterotrophic bacteria and total aerobic heterotrophic bacteria were enumerated along with important water quality parameters in water and sediment samples collected from 3 shrimp farming ponds used for the monoculture of Penaeus monodon as well as from a control pond located outside the shrimp farm. The resistant strains of heterotrophic bacteria were screened against 3 antibiotics (ampicillin, chloramphenicol and oxytetracycline) at 25 and 50 μg/l. The counts of antibiotic resistant bacteria tended to rise in shrimp ponds with progressive rise in the days of culture, but were specially high during the period when both antibiotics and feed were applied in the system. It appears that antibiotics exerted a selective pressure in favour of antibiotic resistant bacterial strains and widespread use of antibiotics should be forbidden in shrimp ponds.
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18

Pratama Novian, Dewan, Irwan Effendi, and Feliatra Feliatra. "GROWTH OF HETEROTROPHIC BACTERIA IN SEA WATER POLLUTED BY SURF DETERGENT." Asian Journal of Aquatic Sciences 1, no. 1 (December 28, 2018): 29–34. http://dx.doi.org/10.31258/ajoas.1.1.29-34.

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The research was conducted from February 2016 to April 2017, aimed to determine the effect of adding different concentrations of detergent namely SURF on the growth of bacterial populations in the seawater column. This research used experimental method with Completely Randomized Design. Seawater samples were analyzed at Marine Microbiology Laboratory, Fisheries and Marine Faculty of Riau University. Based on the results of the study, from day 0 untill day 10 after given detergent with different concentrations, bacteria experienced a decreasing trend of growth, in day 15 untill day 20, the trend of bacterial growth contaminated by detergent with different concentration relatively increased to stagnant. Based on the result of this study the addition of different detergent concentration in each treatment affect the growth of heterotrophic bacteria population in the sea water, where the higher concentration of detergent added the lower the ability of bacteria to grow and the ability of heterotrophic bacteria to survive at different concentrations of detergent, it can be concluded that the ability of heterotrophic bacteria to grow from days 0 to 20 has decreased in each of its concentrations.
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Allen, Andrew E., Melissa G. Booth, Marc E. Frischer, Peter G. Verity, Jonathan P. Zehr, and Sabino Zani. "Diversity and Detection of Nitrate Assimilation Genes in Marine Bacteria." Applied and Environmental Microbiology 67, no. 11 (November 1, 2001): 5343–48. http://dx.doi.org/10.1128/aem.67.11.5343-5348.2001.

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ABSTRACT A PCR approach was used to construct a database of nasAgenes (called narB genes in cyanobacteria) and to detect the genetic potential for heterotrophic bacterial nitrate utilization in marine environments. A nasA-specific PCR primer set that could be used to selectively amplify the nasA gene from heterotrophic bacteria was designed. Using seawater DNA extracts obtained from microbial communities in the South Atlantic Bight, the Barents Sea, and the North Pacific Gyre, we PCR amplified and sequencednasA genes. Our results indicate that several groups of heterotrophic bacterial nasA genes are common and widely distributed in oceanic environments.
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20

Roth, D., and H. Lemmer. "Biofilms in Sewer Systems – Characterization of the Bacterial Biocenosis and Its Metabolic Activity." Water Science and Technology 29, no. 7 (April 1, 1994): 385–88. http://dx.doi.org/10.2166/wst.1994.0367.

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Biofilms sampled from sewers discharging domestic and trade wastewater, respectively, were characterized by determining the population densities of different groups of heterotrophic bacteria as well as by measuring their metabolic activities. Population densities of heterotrophic saprophytes, of proteolytic, amylolytic, and lipolytic bacteria as well as of ammonifying, nitrate reducing and anaerobic bacteria were determined on solid media and by MPN-tests. Metabolic activity was assessed by measuring enzyme activity of esterase, L-alanine-aminopeptidase, phosphatase, as well as of α- and β-glucosidase. Both biofilms revealed high population densities of bacteria from several metabolic groups as well as high enzyme activities. Their heterotrophic activity is in the range of or even higher than that found in high load activated sludges. The high activity of the bacterial biocenosis proves its resistance against high concentrations of chromium and nickel.
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21

Van Wambeke, F., S. Bonnet, T. Moutin, P. Raimbault, G. Alarçon, and C. Guieu. "Factors limiting heterotrophic bacterial production in the southern Pacific Ocean." Biogeosciences Discussions 4, no. 5 (October 16, 2007): 3799–828. http://dx.doi.org/10.5194/bgd-4-3799-2007.

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Abstract. The role of potential factors limiting bacterial growth was investigated along vertical and longitudinal gradients across the South Eastern Pacific Gyre. The effects of glucose, nitrate, ammonium and phosphate additions on heterotrophic bacterial production (using leucine technique) were studied in parallel in unfiltered seawater samples incubated under natural daily irradiance. Longitudinally, the enrichments realized on the subsurface showed three types of responses. From the Marquesas plateau (8° W to approx 125° W), bacteria were not bottom-up controlled, as confirmed by the huge potential of growth in non-enriched seawater (43±24 times in 24 h). Within the Gyre (125° W–95° W), nitrogen alone stimulated leucine incorporation rates by a factor of 5.6±3.6, but rapidly labile carbon (glucose) became a second limiting factor (enhancement factor 49±32 when the two elements were added). Finally from the border of the gyre to the Chilean upwelling (95° W–73° W), labile carbon was the only factor stimulating heterotrophic bacterial production. Interaction between phytoplankton and heterotrophic bacterial communities and the direct versus indirect effect of iron and macronutrients on bacterial production were also investigated in four selected sites: two sites on the vicinity of the Marquesas plateau, the centre of the gyre and the Eastern border of the gyre. Both phytoplankton and heterotrophic bacteria were limited by availability of nitrogen within the gyre, but not by iron. While iron limited phytoplankton at Marquesas plateau and at the eastern border of the gyre, heterotrophic bacteria were only limited by availability of labile DOC in those environments.
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22

Tsuneda, S., S. Park, H. Hayashi, J. Jung, and A. Hirata. "Enhancement of nitrifying biofilm formation using selected EPS produced by heterotrophic bacteria." Water Science and Technology 43, no. 6 (March 1, 2001): 197–204. http://dx.doi.org/10.2166/wst.2001.0374.

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The possibility of enhancing nitrifying biofilm formation rate with the aid of selected EPS produced by heterotrophic bacteria was investigated. When EPS production characteristics were examined for four kinds of heterotrophs isolated from a domestic wastewater treatment reactor, two strains obtained from biofilms (B1, B2) exhibited a higher polysaccharide production rate than those from suspended flocs (A1, A2). Among EPS components, the concentration of uronic acids gave a good correlation with flocculation ability, which suggests that acidic polysaccharides play a major role in bioaggregate formation. Addition of 1g/L D-glucuronic acid as an EPS substitute enhanced the homocoagulation rate of autotrophic Nitrosomonas europaea and altered its zeta potential from ñ30.4mV to +4.3mV, which indicates a possibility that particular EPS components produced by heterotrophs are utilized as neutralising reagents for nitrifying biofilm formation. Moreover, when heterotrophic isolates with Nitrobacter winogradskyi were cultured in batch with fabric supports, biofilm formed on the substratum. These experimental results suggest the application of selected EPS for enhancing nitrifying biofilm formation.
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Galachyants, Agnia, Irina Tomberg, Elena Sukhanova, Yulia Shtykova, Maria Suslova, Ekaterina Zimens, Vadim Blinov, Maria Sakirko, Valentina Domysheva, and Olga Belykh. "Bacterioneuston in Lake Baikal: Abundance, Spatial and Temporal Distribution." International Journal of Environmental Research and Public Health 15, no. 11 (November 19, 2018): 2587. http://dx.doi.org/10.3390/ijerph15112587.

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An aquatic surface microlayer covers more than 70% of the world’s surface. Our knowledge about the biology of the surface microlayer of Lake Baikal, the most ancient lake on Earth with a surface area of 31,500 km2, is still scarce. The total bacterial abundance, the number of cultured heterotrophic temporal bacteria, and the spatial distribution of bacteria in the surface microlayer and underlying waters of Lake Baikal were studied. For the first time, the chemical composition of the surface microlayer of Lake Baikal was determined. There were significant differences and a direct relationship between the total bacterial abundance in the surface microlayer and underlying waters of Lake Baikal, as well as between the number of cultured heterotrophic bacteria in studied water layers in the period of summer stratification. In the surface microlayer, the share of cultured heterotrophic bacteria was higher than in the underlying waters. The surface microlayer was characterized by enrichment with PO43−, total organic carbon and suspended particulate matter compared to underlying waters. A direct relationship was found between the number of bacteria in the surface microlayer and environmental factors, including temperature, total organic carbon and suspended particulate matter concentration.
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Pathiraja, Pathiraja Mudiyanselage Duleepa, and In-Geol Choi. "해양 종속영양세균의 한천대사에 대한 새로운 통찰." Institute of Life Science and Natural Resources 30 (December 31, 2022): 53–65. http://dx.doi.org/10.33147/lsnrr.2022.30.1.53.

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Agar is a key structural polysaccharide of red macroalgae which provides a rich habitat for marine heterotrophic bacteria in marine ecosystems. Marine agarolytic bacteria, that can use agar as the sole carbon source, are distributed in diverse marine environments from open coastal waters to the gut of marine herbivores. Agarolytic bacteria employ a combination of carbohydrate-active enzymes (CAZymes) for the depolymerization of agar. Extensive studies on the genomic architecture of the agarolytic bacteria suggested that genes encoding these CAZymes are arranged in polysaccharide utilization loci (PUL). Agar hydrolyzing enzymes (agarases) are categorized into; β-agarase (GH16, GH50, GH86, and GH118), α-agarase (GH96), neoagarooligosaccharide hydrolase (GH117), and agarolytic β-galactosidase (GH2). The molecular functionality, structural elements, and catalytic mechanisms of agarases belonging to different GH families show unique characteristics. L-AHG, one of the main constituents in agar, is a rare monosaccharide and its metabolic pathway is exclusively found in marine agarolytic bacteria. Recent trends in the agarolytic systems are mostly focused on the sequence data to visualize the universal agarolytic enzyme repertoire and the evolution of the agarolytic pathway in marine heterotrophic bacteria. In addition, increasing attention is paid to understanding the oligosaccharide transport mechanisms and transcriptional regulation of genes in PUL. In this review, we will cover a comprehensive overview of genomic architecture, structural and functional analysis of agar hydrolyzing enzymes, and agar metabolism in marine heterotrophic bacteria.
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Hutchens, E., E. Valsami-Jones, S. McEldowney, W. Gaze, and J. McLean. "The role of heterotrophic bacteria in feldspar dissolution – an experimental approach." Mineralogical Magazine 67, no. 6 (December 2003): 1157–70. http://dx.doi.org/10.1180/0026461036760155.

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AbstractThis paper presents the results of a laboratory study on the influence of heterotrophic bacteria on dissolution of a silicate mineral (K-feldspar) under a variety of growth conditions. Twenty seven strains of heterotrophic bacteria were isolated from a feldspar-rich soil (Shap, NW England). Liquid and solid minimal aerobic media (C/N-sufficient, K-limited, Fe-limited, N-limited and glucose/NH4Cl only) at 26ºC were used for isolation of the bacteria. The media selected bacterial isolates that were fastgrowing aerobic heterotrophs able to use glucose as the sole source of carbon and energy. The extent of mineral dissolution (in the presence of the isolates) was assessed after 48 h of incubation by measuring the release of Al from the K-feldspar by ICP-AES. More detailed dissolution experiments were carried out with one of the strains, Serratia marcescens, an isolate that was very effective in enhancing feldspar dissolution. The main conclusions of this study are: (1) the degree of enhancement of K-feldspar dissolution varied with bacterial isolate and growth conditions; (2) enhancement of dissolution began during stationary phase growth; (3) the production of chelating compounds (exopolymers, siderophores, pigments) during the stationary phase might be a possible mechanism for bacterially enhanced K-feldspar dissolution; (4) the frequent sub-culturing of isolates can have a significant effect on their physiological characteristics and may possibly influence their capacity to enhance mineral dissolution.
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Okabe, S., T. Kindaichi, Y. Nakamura, and T. Ito. "Eco-physiology of autotrophic nitrifying biofilms." Water Science and Technology 52, no. 7 (October 1, 2005): 225–32. http://dx.doi.org/10.2166/wst.2005.0205.

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Microautoradiography combined with fluorescent in situ hybridization (MAR-FISH), a powerful tool for linking physiology with identification of individual cells, was applied to investigate microbial interactions between nitrifying bacteria and coexisting heterotrophic bacteria in an autotrophic nitrifying biofilm community fed with only ammonia as the sole energy source and bicarbonate as the sole carbon source. First, nitrifying bacteria were radiolabeled by culturing the biofilm samples with [14C]bicarbonate for 6 h, and then the transfer of radioactivity from nitrifying bacteria to heterotrophic bacteria was monitored by using MAR-FISH. MAR-FISH revealed that the heterotrophic bacterial community was composed of bacteria that were phylogenetically and metabolically diverse. We could obtain direct evidence that organic matter derived from nitrifiers was subsequently utilized by mainly filamentous bacteria belonging to the Chloroflexi (green non-sulfur bacteria) group or CFB group in the biofilm, which was clearly visualized by MAR-FISH at single cell resolution for the first time. On the other hand, the members of the α- and γ-Proteobacteria were specialized to utilize low-molecular-weight organic matter. This community represents functionally integrated units that assure maximum access to and utilization of metabolites of nitrifiers.
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Timilshina, M., I. Dahal, and B. Thapa. "Microbial assessment of bottled drinking water of Kathmandu valley." International Journal of Infection and Microbiology 1, no. 2 (January 20, 2013): 84–86. http://dx.doi.org/10.3126/ijim.v1i2.7399.

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INTRODUCTION: Due to increased demand and consumption of bottled water in Kathmandu valley, there has been a growing concern about the microbiological quality of this product. The objective of this study was to assess the microbial contamination of heterotrophs and total coliform. MATERIALS AND METHODS: This cross sectional study was done in randomly selected 30 different commercial brand of bottled water available in commercial market of Kathmandu valley, Nepal. Total coliform and heterotrophic bacteria were enumerated by the membrane filtration and spread plate technique, respectively. RESULTS: Nineteen samples (63.3%) showed the heterotrophic bacterial count above the acceptable range (i.e. <50 cfu/ml) and 56.6% (n=17) samples showed the total coliforms count crossed the WHO guidelines (i.e. 0 cfu/ml). 83.3% (n=25) brands of bottled water were not safe for drinking as they exceed the heterotrophic and/or total coliform count above the WHO guidelines. CONCLUSIONS: The presence of heterotrophs and the coliform in the bottled water is a serious concern for public health. Concerned authority should prioritize this issue and continuously monitor the quality of mushrooming bottled water manufacturers in Kathmandu valley to provide safe drinking water to the population. DOI: http://dx.doi.org/10.3126/ijim.v1i2.7399 Int J Infect Microbiol 2012;1(1):84-86
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Van Wambeke, F., S. Bonnet, T. Moutin, P. Raimbault, G. Alarcón, and C. Guieu. "Factors limiting heterotrophic bacterial production in the southern Pacific Ocean." Biogeosciences 5, no. 3 (May 19, 2008): 833–45. http://dx.doi.org/10.5194/bg-5-833-2008.

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Abstract. The role of potential factors limiting bacterial growth was investigated along vertical and longitudinal gradients across the South Eastern Pacific Gyre. The effects of glucose, nitrate, ammonium and phosphate additions on heterotrophic bacterial production (using leucine technique) were studied in parallel in unfiltered seawater samples incubated under natural daily irradiance. The enrichments realized on the subsurface showed three types of responses. From 141° W (Marquesas plateau) to approx 125° W, bacteria were not bottom-up controlled, as confirmed by the huge potential of growth in non-enriched seawater (median of enhancement factor×39 in 24 h). Within the Gyre (125° W–95° W), nitrogen alone stimulated leucine incorporation rates (median×4.2), but rapidly labile carbon (glucose) became a second limiting factor (median×37) when the two elements were added. Finally from the border of the gyre to the Chilean upwelling (95° W–73° W), labile carbon was the only factor stimulating heterotrophic bacterial production. Interaction between phytoplankton and heterotrophic bacterial communities and the direct versus indirect effect of iron and macronutrients on bacterial production were also investigated in four selected sites: two sites on the vicinity of the Marquesas plateau, the centre of the gyre and the Eastern border of the gyre. Both phytoplankton and heterotrophic bacteria were limited by availability of nitrogen within the gyre, but not by iron. Iron limited phytoplankton at Marquesas plateau and at the eastern border of the gyre. However 48 h enrichment experiments were not sufficient to show any clear limitation of heterotrophic bacteria within Marquesas plateau and showed a limitation of these organisms by labile carbon in the eastern border of the Gyre.
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Lud Waluyo, Nyono, Sukarsono, Atok Miftachul Hudha, and Abdulkadir Raharjanto. "Synergism of Consortium of Heterotrophic Bacterial Strains with Pistia stratiotes L. and Salvinia molesta D. Mitch as Biophytoremediator for Heavy Metal Removal in Domestic Wastewater." HAYATI Journal of Biosciences 31, no. 1 (September 19, 2023): 21–29. http://dx.doi.org/10.4308/hjb.31.1.21-29.

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High levels of organic matter and heavy metals in domestic wastewater can increase the pollution of water bodies. The water pollution results correspond to the degree of public health. Waste must be controlled and processed first using management methods such as biophytoremedyator to decrease the rate of pollution because its advantages do not negatively impact public health and the environment. Biophytoremediation offers a better alternative method to repair environmental conditions by combining microorganisms and plants. This study aimed to analyze the effect of heterotrophic bacterial strains with Pistia stratiotes L. and Salvinia molesta D. Mitch for heavy metal removal in domestic wastewater. It also investigated the influence of heterotrophic bacterial strains with Pistia stratiotes L. and Salvinia molesta D. Mitch which were also carried out to observe the BOD and COD levels. The results showed decreased heavy metal levels from the three treatment groups. The consortium treatment group of heterotrophs and Salvinia molesta D. Mitch bacteria strains reduced heavy metal levels faster than the other groups by 59%. In addition, it is also able to reduce BOD and COD levels. This study has shown the significant effect of combining heterotrophic bacterial (HB) strains with Pistia stratiotes L. or Salvinia molesta D. Mitch for heavy metal removal in domestic wastewater.
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Rapala, J., M. Niemelä, K. A. Berg, L. Lepistö, and K. Lahti. "Removal of cyanobacteria, cyanotoxins, heterotrophic bacteria and endotoxins at an operating surface water treatment plant." Water Science and Technology 54, no. 3 (August 1, 2006): 23–28. http://dx.doi.org/10.2166/wst.2006.443.

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The removal of cyanobacteria, hepatotoxins produced by them (microcystins), phytoplankton, heterotrophic bacteria and endotoxins were monitored at a surface water treatment plant with coagulation, clarification, sand filtration, ozonation, slow sand filtration and chlorination as the treatment process. Coagulation–sand filtration reduced microcystins by 1.2–2.4, and endotoxins by 0.72–2.0 log10 units. Ozonation effectively removed the residual microcystins. The treatment process reduced phytoplankton biomass by 2.2–4.6 and heterotrophic bacteria by 2.0–5.0 log10 units. In treated water, the concentration of microcystins never exceeded the WHO guide value (1 μg/L), but picoplankton and monad cells were often detected in high numbers. The heterotrophic bacterial isolates from the treated waters belonged to genera Sphingomonas, Pseudomonas, Bacillus, Herbaspirillum and Bosea.
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Feliatra, F., Rizki Hamdani, Iesye Lukystyowati, and Irvina Nurachmi. "Sensitivity of Heterotrophic Bacteria in the Low-Salinity Water Areas and Estuary in Siak District toward Pathogenic Bacteria in Fish." International Journal of Microbiology 2019 (June 10, 2019): 1–8. http://dx.doi.org/10.1155/2019/7456410.

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The high rate of bacterial diseases in fishes and shrimps has lead scientists seek for natural antibiotic products that would act as a solution. An example of this product is the secondary metabolic products from heterotrophic bacteria. These bacteria could easily be found in many water regions and estuaries, including the Siak District, Riau, Indonesia. Therefore, this study aims at determining the ability of bacterial isolates in inhibiting the growth of pathogens (Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas sp.). The research was conducted from June to September 2018. It actuates the type of heterotrophic bacteria in the sampling area using the PCR technique. The phylogenetic structure of bacterial isolates obtained during this study was assessed by nucleotide sequencing of the 16S rRNA gene. The antagonism test showed that bacteria had the ability to inhibit the growth of pathogens (Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas sp.). The results showed that 25 pure bacterial isolates were obtained, in which 10 of those were carried out by DNA sequencing; hence, it could be used as antimicrobes. Based on the analysis of 16S rDNA, 10 isolates were identified: 6 were Bacillus cereus and 2 were Pseudomonas aeruginosa with homology levels ranging from 97 to 99%, while the remaining two were suspected as the new species of isolates. From the result, it could be concluded that heterotrophic bacteria are found to be better used as antipathogens against Vibrio alginolitycus than hydrophila and Pseudomonas sp.
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Kopylov, A. I., D. B. Kosolapov, and I. V. Rybakova. "Population, biomass, and production of heterotrophic bacteria in reservoirs of the Upper Volga." Водные ресурсы 46, no. 1 (January 15, 2019): 35–42. http://dx.doi.org/10.31857/s0321-059646135-42.

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Populations, biomasses, and production rates of planktonic, epiphytic, and benthic bacterial communities were defined in two reservoirs of the upper Volga, and their contributions to total numbers of bacteria and productivity were estimated. Populations and production rates of heterotrophic bacteria in 1-cm3 samples of bottom sediments exceed fouling of higher aquatic plants by a factor of 101–102, and in the water layers by a factor of 103–104. In mesotrophic Rybinsk and eutrophic Ivankovskoye reservoirs, benthic bacteria account for 90.4% and 98.8% of the total biomass, and 99.5% and 95.8% of total heterotrophic bacterial products, respectively. In these reservoirs, dissolved organic carbon accounts for 9.55% and 1.19% of the biomass and 4.12% and 0.45% of production, and epiphytic bacteria account for 0.05% and 0.03% of the biomass and 0.03% and 0.02% of production. These findings suggest important roles of benthic bacterial populations in reservoirs of the upper Volga.
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Goñi-Urriza, Marisol, Michèle Capdepuy, Nathalie Raymond, Claudine Quentin, and Pierre Caumette. "Impact of an urban effluent on the bacterial community structure in the Arga River (Spain), with special reference to culturable Gram-negative rods." Canadian Journal of Microbiology 45, no. 10 (October 1, 1999): 826–32. http://dx.doi.org/10.1139/w99-073.

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The Arga River is an interesting system in which to study the impact of urban effluent pollution because it receives a single effluent in the form of wastewater discharge from the city of Pamplona. To analyze the extent of this discharge, total bacteria, culturable heterotrophic bacteria, and Gram-negative heterotrophic bacteria were enumerated and 409 isolates of the latter were identified. One sampling station was located upstream from the inflow, while five were located up to 30 km downstream. Bacterial counts increased drastically downstream from the wastewater inflow. Total bacterial numbers decreased along the 30 km downstream, the last station attaining similar values to those recorded upstream from the discharge. However, culturable heterotrophic and Gram-negative heterotrophic bacteria levels generally remained significantly higher within the 30 km zone investigated. Among the 409 isolates identified, Aeromonas spp. were the most frequent both upstream and downstream from the discharge. In contrast, although strains belonging to different genera of Enterobacteriaceae were found in all stations, their occurrence was significantly higher just downstream from the polluted discharge. Acinetobacter spp., which were never found upstream, were detected in all stations below the discharge. Our results clearly show that the bacterial community structure changes definitively downstream from the discharge and that Aeromonas were common throughout the sampling zone. Thus they cannot be considered good indicators of pollution in this setting compared to some genera of Enterobacteriaceae or some species ofAcinetobacter, the distribution of which correlated better with the distance from the wastewater discharge.Key words: Aeromonas, Enterobacteriaceae, sewage, freshwater.
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Sedlacek, Christopher J., Susanne Nielsen, Kenneth D. Greis, Wendy D. Haffey, Niels Peter Revsbech, Tomislav Ticak, Hendrikus J. Laanbroek, and Annette Bollmann. "Effects of Bacterial Community Members on the Proteome of the Ammonia-Oxidizing Bacterium Nitrosomonas sp. Strain Is79." Applied and Environmental Microbiology 82, no. 15 (May 27, 2016): 4776–88. http://dx.doi.org/10.1128/aem.01171-16.

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ABSTRACTMicroorganisms in the environment do not exist as the often-studied pure cultures but as members of complex microbial communities. Characterizing the interactions within microbial communities is essential to understand their function in both natural and engineered environments. In this study, we investigated how the presence of a nitrite-oxidizing bacterium (NOB) and heterotrophic bacteria affect the growth and proteome of the chemolithoautotrophic ammonia-oxidizing bacterium (AOB)Nitrosomonassp. strain Is79. We investigatedNitrosomonassp. Is79 in co-culture withNitrobacter winogradskyi, in co-cultures with selected heterotrophic bacteria, and as a member of the nitrifying enrichment culture G5-7. In batch culture,N. winogradskyiand heterotrophic bacteria had positive effects on the growth ofNitrosomonassp. Is79. An isobaric tag for relative and absolute quantification (iTRAQ) liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics approach was used to investigate the effect ofN. winogradskyiand the co-cultured heterotrophic bacteria from G5-7 on the proteome ofNitrosomonassp. Is79. In co-culture withN. winogradskyi, severalNitrosomonassp. Is79 oxidative stress response proteins changed in abundance, with periplasmic proteins increasing and cytoplasmic proteins decreasing in abundance. In the presence of heterotrophic bacteria, the abundance of proteins directly related to the ammonia oxidation pathway increased, while the abundance of proteins related to amino acid synthesis and metabolism decreased. In summary, the proteome ofNitrosomonassp. Is79 was differentially influenced by the presence of eitherN. winogradskyior heterotrophic bacteria. Together,N. winogradskyiand heterotrophic bacteria reduced the oxidative stress forNitrosomonassp. Is79, which resulted in more efficient metabolism.IMPORTANCEAerobic ammonia-oxidizing microorganisms play an important role in the global nitrogen cycle, converting ammonia to nitrite. In their natural environment, they coexist and interact with nitrite oxidizers, which convert nitrite to nitrate, and with heterotrophic microorganisms. The presence of nitrite oxidizers and heterotrophic bacteria has a positive influence on the growth of the ammonia oxidizers. Here, we present a study investigating the effect of nitrite oxidizers and heterotrophic bacteria on the proteome of a selected ammonia oxidizer in a defined culture to elucidate how these two groups improve the performance of the ammonia oxidizer. The results show that the presence of a nitrite oxidizer and heterotrophic bacteria reduced the stress for the ammonia oxidizer and resulted in more efficient energy generation. This study contributes to our understanding of microbe-microbe interactions, in particular between ammonia oxidizers and their neighboring microbial community.
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Lasternas, S., and S. Agustí. "Bacterial survival governed by organic carbon release from senescent oceanic phytoplankton." Biogeosciences Discussions 10, no. 10 (October 30, 2013): 16973–99. http://dx.doi.org/10.5194/bgd-10-16973-2013.

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Abstract. Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g. sloppy feeding, cell exudation, viral lysis) involved in the transference of primary production to dissolved organic carbon available to bacteria. Here we show cell survival of heterotrophic bacterioplankton in the subtropical Atlantic Ocean to be determined by phytoplankton extracellular carbon release (PER). PER represents the fraction of primary production released as dissolved organic carbon, and changes in the PER variability was explained by phytoplankton cell death, with the communities experiencing the highest phytoplankton cell mortality showing a larger proportion of extracellular carbon release. Both PER and the percent of dead phytoplankton cells increased from eutrophic to oligotrophic waters, while heterotrophic bacteria communities, including 60 to 95% of living cells (%LC), increased from the productive to the most oligotrophic waters. The percentage of living heterotrophic bacterial cells increased with increasing phytoplankton extracellular carbon release, across oligotrophic to productive waters in the NE Atlantic, where lower PER have resulted in a decrease in the flux of phytoplankton DOC per bacterial cell. The results highlight phytoplankton cell death as a process influencing the flow of dissolved photosynthetic carbon in the NE Atlantic Ocean, and demonstrated a close coupling between the fraction of primary production released and heterotrophic bacteria survival.
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Christaki, U., D. Lefèvre, C. Georges, J. Colombet, P. Catala, C. Courties, T. Sime-Ngando, S. Blain, and I. Obernosterer. "Microbial food web dynamics during spring phytoplankton blooms in the naturally iron-fertilized Kerguelen area (Southern Ocean)." Biogeosciences 11, no. 23 (December 5, 2014): 6739–53. http://dx.doi.org/10.5194/bg-11-6739-2014.

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Abstract. Microbial food web dynamics were determined during the onset of several spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island in the Southern Ocean (KEOPS2). The abundances of heterotrophic bacteria and heterotrophic nanoflagellates, bacterial heterotrophic production, bacterial respiration, and bacterial growth efficiency, were consistently higher in surface waters of the iron-fertilized sites than at the reference site in HNLC (high nutrient low chlorophyll) waters. The abundance of virus-like particles remained unchanged, but viral production increased by a factor of 6 in iron-fertilized waters. Bacterial heterotrophic production was significantly related to heterotrophic nanoflagellate abundance and viral production across all sites, with bacterial production explaining about 70 and 85%, respectively, of the variance of each in the mixed layer (ML). Estimated rates of grazing and viral lysis, however, indicated that heterotrophic nanoflagellates accounted for a substantially higher loss of bacterial production (50%) than viruses (11%). Combining these results with rates of primary production and export determined for the study area, a budget for the flow of carbon through the microbial food web and higher trophic levels during the early (KEOPS2) and the late phase (KEOPS1) of the Kerguelen bloom is provided.
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Christaki, U., D. Lefèvre, C. Georges, J. Colombet, P. Catala, C. Courties, T. Sime-Ngando, S. Blain, and I. Obernosterer. "Microbial food web dynamics during spring phytoplankton blooms in the naturally iron-fertilized Kerguelen area (Southern Ocean)." Biogeosciences Discussions 11, no. 5 (May 16, 2014): 6985–7028. http://dx.doi.org/10.5194/bgd-11-6985-2014.

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Abstract. Microbial food web dynamics were determined during the onset of several spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island in the Southern Ocean (KEOPS2). The abundances of heterotrophic bacteria and heterotrophic nanoflagellates, bacterial heterotrophic production, bacterial respiration, and bacterial growth efficiency, were consistently higher in surface waters of the iron-fertilized sites than at the reference site in HNLC (high nutrient low chlorophyll) waters. The abundance of viral like particles remained unchanged, but viral production increased by a factor of 6 in iron-fertilized waters. Bacterial heterotrophic production was significantly related to heterotrophic nanoflagellate abundance and viral production across all sites, with bacterial production explaining about 70 and 85%, respectively, of the variance of each in the mixed layer (ML). Estimated rates of grazing and viral lysis, however, indicated that heterotrophic nanoflagellates accounted for a substantially higher loss of bacterial production (50%) than viruses (11%). Combining these results with rates of primary production and export determined for the study area, a budget for the flow of carbon through the microbial food web and higher levels during the early (KEOPS2) and the late phase (KEOPS1) of the Kerguelen bloom is provided.
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Ferreira, Ana-Cristina, Paula Vasconcellos Morais, and Milton S. da Costa. "Alterations in total bacteria, iodonitrophenyltetrazolium (INT)-positive bacteria, and heterotrophic plate counts of bottled mineral water." Canadian Journal of Microbiology 40, no. 1 (January 1, 1994): 72–77. http://dx.doi.org/10.1139/m94-012.

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The quantitative variation in the microflora in bottled mineral waters stored in polyvinyl chloride bottles was studied immediately after bottling and after 7 days storage, over 9 months. The microflora was determined by combining total counts using ethidium bromide, and the number of iodonitrophenyltetrazolium (INT)-positive cells determined with heterotrophic plate counts on R2A for prolonged incubation periods at 22 and 37 °C. Immediately after bottling of mineral water A, the total counts with ethidium bromide varied between 70.0 and 495.0 bacteria/mL. The number of INT-positive bacteria varied between 14.0 and 40.0% counts. The heterotrophic plate counts were higher at 22 °C than at 37 °C and varied between 1.1 and 13.2% and between 0.7 and 9.3% of the total counts, respectively. After 7 days storage, total bacterial counts increased by 1000 times, indicating multiplication of bacteria that were present in low numbers immediately after bottling. The percentage of INT-positive bacteria remained between 2.6 and 39.0% of the total counts but the number of culturable bacteria was higher than the number of INT-positive cells. Similar counts were found in other mineral waters (B, C, and D), but the numbers of INT-positive cells in two of them (B and D) were higher than the heterotrophic plate counts at 22 °C. These results show the presence in the aquifer and (or) bottling system of a flora that is neither INT-positive nor culturable and reinforce previous results that still mineral waters have a large bacterial population after storage.Key words: mineral water, bacterial populations, ethidium bromide, INT, HPC.
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39

Figel, Izabel Cristina, Patricia do Rocio Dalzoto, and Ida Chapaval Pimentel. "Microbiological quality of water and dialysate from haemodialysis units in Southern Brazil." Revista do Instituto Adolfo Lutz 74, no. 1 (October 5, 2015): 66–70. http://dx.doi.org/10.53393/rial.2015.v74.33387.

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Infectious diseases in renal patients may be associated with the dialysis water quality, which may be contaminated with microorganisms. In Brazil, the water quality is evaluated by analyzing total coliforms, heterotrophic bacteria, and bacterial endotoxin, but not Pseudomonas sp. and fungi. Water samples from haemodialysis units in Curitiba/PR were investigated on their conformity with the standard established by the Brazilian Health Ministry. Total coliforms, heterotrophic bacteria, P. aeruginosa and fungi counts were performed according to APHA, and LAL methodology for detecting bacterial endotoxin. All of the samples showed the total coliforms counts ≤1.1 MPN/100 mL,and ≥ 95 % of analyzed samples complied with the standards for heterotrophic bacteria counting. P. aeruginosa was recovered from 4 % of samples. In 15 % of samples, bacterial endotoxin was detected in values above the limit established by legislation. Yeasts were isolated from 26 % samples and filamentous fungi from 58 %, being 46 % characterized as melanized fungi. The fungi genera were Cladosporium spp., Penicillium spp., Beauveria spp., Exophiala spp., Fusarium spp., Aspergillus spp., Trichoderma spp, Acremonium spp. and Rinocladiella spp.. The study highlights the significance of P. aeruginosa and fungi detection in those systems, as these microorganisms are potentially pathogenic to immunocompromised patients.
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Simo-Matchim, AG, M. Gosselin, and C. Belzile. "Multivariate control of heterotrophic bacterial abundance and zooplankton grazing in Labrador fjords (northeastern Canada)." Aquatic Microbial Ecology 84 (April 16, 2020): 105–20. http://dx.doi.org/10.3354/ame01929.

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This study was conducted in 4 Labrador fjords (Nachvak, Saglek, Okak, and Anaktalak) during the summers of 2007 and 2013, early fall 2010, and late fall 2009. Our results show that water temperature combined with the availability of nutrients and organic substrates are the main abiotic factors controlling the abundance of heterotrophic bacteria in Labrador fjords. Bacterivory also played a crucial role, with heterotrophic bacteria exerting a significant bottom-up control on the abundance of heterotrophic nanoflagellates (r = 0.35, p < 0.05) and ciliates (r = 0.70, p < 0.01). During summer 2013, the intrinsic phytoplankton growth rate varied between <0 and 0.64 d-1, with a mean value of 0.36 d-1. The herbivory rate was highly variable, ranging from 0.01 to 0.86 d-1, with a mean value of 0.31 d-1. Grazing mortality was 6-fold higher than phytoplankton growth rate. Mean phytoplankton growth and herbivory rates in Labrador fjords were comparable to the Barents and Bering seas. The intrinsic growth rate of total heterotrophic bacteria ranged between <0 and 0.68 d-1, with a mean value of 0.30 d-1. Bacterivory varied from 0.01 to 0.95 d-1, with a mean of 0.30 d-1. Mortality due to grazing was up to 2.3 times higher than total bacterial growth rate. This study improves our understanding of the factors influencing the dynamics of heterotrophic bacteria and indicates that herbivory and bacterivory exert substantial control on microbial communities in Labrador fjords.
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41

P. Palan, Shailaja, and Shilpa M. Gharat. "Abundance of Heterotrophic Bacterial Population in Coastal Waters of Palghar Taluka, Maharashtra, India." Ecology, Environment and Conservation 30, Suppl (2024): 128–31. http://dx.doi.org/10.53550/eec.2024.v30i01s.023.

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The population density of total heterotrophic bacteria in coastal water at 4 different sites along Palghar taluka namely; Kelwa coast, Navapur coast, Dandi creek and Satpati coast were studied. Total heterotrophic bacterial count was found to range from 0.34×102 – 423.1× 102 CFUml-1 in coastal waters. Average heterotrophic bacterial abundance was noted higher during monsoon at all 4 sites in the study with 47.2× 102 ± 34.79 CFU ml1at Satpati coast, 281.55× 102 ± 148.45 CFU ml-1 at Dandi creek, 265.26× 102 ± 149.74 CFU ml-1 at Navapur coast, and 1.12 × 102 ± 0.54 CFU ml-1 at Kelwa coast. Dandi creek recorded highest bacterial count throughout study period irrespective of season.
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42

Lasternas, S., and S. Agustí. "The percentage of living bacterial cells related to organic carbon release from senescent oceanic phytoplankton." Biogeosciences 11, no. 22 (November 26, 2014): 6377–87. http://dx.doi.org/10.5194/bg-11-6377-2014.

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Abstract. Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g., sloppy feeding, cell exudation, viral lysis) involved in the transfer of primary production to dissolved organic carbon available to bacteria. Here, we show the percentage of living heterotrophic bacterioplankton in the subtropical NE Atlantic Ocean in relation to phytoplankton extracellular carbon release (PER). PER represents the fraction of primary production released as dissolved organic carbon. PER variability was explained by phytoplankton cell death, with communities experiencing higher phytoplankton cell mortality showing a larger proportion of phytoplankton extracellular carbon release. Both PER and the percentage of dead phytoplankton cells increased from eutrophic to oligotrophic waters, while abundance of heterotrophic bacteria was highest in the intermediate waters. The percentage of living heterotrophic bacterial cells (range: 60–95%) increased with increasing phytoplankton extracellular carbon release from productive to oligotrophic waters in the subtropical NE Atlantic. The lower PERs, observed at the upwelling waters, have resulted in a decrease in the flux of phytoplankton dissolved organic carbon (DOC) per bacterial cell. The results highlight phytoplankton cell death as a process influencing the flow of dissolved photosynthetic carbon in this region of the subtropical NE Atlantic Ocean, and suggest a close coupling between the fraction of primary production released and heterotrophic bacterial cell survival.
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43

Nikolova, Radina, Michaella Petkova, Nikolai Dinev, Anelia Kenarova, Silvena Boteva, Dimitar Berov, and Galina Radeva. "Correlation between bacterial abundance, soil properties and heavy metal contamination in the area of non-ferrous metal processing plant, Southern Bulgaria." BioRisk 17 (April 21, 2022): 19–30. http://dx.doi.org/10.3897/biorisk.17.77458.

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In the present study, the correlation between bacterial abundance and soil physicochemical properties along the heavy metal contamination gradient in the area of non-ferrous metal processing plant was assessed. Our results showed that bacterial abundance (number of heterotrophic bacteria and number of 16S rRNA gene copies) decreased with 45–56% (CFU) and 54–87% (16S rRNA gene) along the Zn, Pb and Cd contamination gradient. The total bacterial abundance (16S rRNA gene) increased exponentially in contrast to the abundance of heterotrophic bacteria. The reduction of bacterial abundance in heavily contaminated soil indicated that the soil properties (soil pH, total organic carbon, inorganic ions, soil texture) could modify the effects of heavy metals and the response of microorganisms to that stress in long-term contaminated soils.
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44

Hatha, A. A. M., K. S. Christi, R. Singh, and S. Kumar. "Bacteriology of the fresh water bivalve clam Batissa violacea (Kai) sold in the Suva market." South Pacific Journal of Natural and Applied Sciences 23, no. 1 (2005): 48. http://dx.doi.org/10.1071/sp05009.

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Forty samples of freshwater clam (Batissa violacea), popularly known as Kai, collected from the Suva market were analysed for total aerobic plate count and total coliforms. The heterotrophic bacteria isolated by plate count were also characterised up to genera. The results indicated higher than acceptable level of plate count and coliform bacteria. While total plate count of aerobic heterotrophic bacteria ranged from 5.5 x 105 colony forming units (cfu) per gram to more than 107 cfu/ gram, total coliform load varied between 1.1 x 104 to 1.1 x 105 per 100 gm of Kai flesh. The characterisation of the heterotrophic bacteria revealed the predominance of the genera Micrococcus (34%) and Bacillus (24%). Other genera encountered included Acinetobacter, Vibrio, Aeromonas, Alcaligenes, Pseudomonas, Streptococcus and members of the family Enterobacteriaceae. The results revealed the need for depuration of the Kai in clean running water to reduce the bacterial load to acceptable levels. Temperature control soon after harvesting by proper icing and thorough cooking of the Kai before consumption is also recommended.
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45

Wyatt, Kevin H., Jill S. Bange, Andrea S. Fitzgibbon, Melody J. Bernot, and Allison R. Rober. "Nutrients and temperature interact to regulate algae and heterotrophic bacteria in an Alaskan poor fen peatland." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 3 (March 2015): 447–53. http://dx.doi.org/10.1139/cjfas-2014-0425.

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Permafrost thaw associated with warmer temperatures is expected to elevate nutrient levels in northern aquatic ecosystems, including peatlands. To evaluate these effects on algae and heterotrophic bacteria, we manipulated nutrients (nitrogen (N) and phosphorus (P)) and temperature (ambient and warmed) in a factorial design using nutrient diffusing substrates inside warming chambers in an Alaskan peatland. After 16 days, there was no effect of warming on the abundance of algae or heterotrophic bacteria in the absence of nutrient enrichment. Algal production and bacterial biomass were substantially elevated by N with and without P (NP and N, respectively), independent of warming. Warming significantly enhanced the effect of nutrient enrichment on the abundance of algae and heterotrophic bacteria compared with ambient temperatures. Rates of N fixation increased with the presence of heterocyst-forming cyanobacteria, which represented a greater proportion of algal taxonomic composition in the absence of N enrichment in both ambient and warmed conditions. Our results indicate that warmer temperatures and nutrient enrichment will elevate algal and heterotrophic metabolism in northern peatlands, and the magnitude of increase will depend on the combination of nutrients available during periods of inundation.
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46

Fernandes, Ana Júlia, and Hilda de Souza Lima Mesquita. "An experimental study of nanoflagellate bacterivory." Revista de Microbiologia 30, no. 4 (December 1999): 369–72. http://dx.doi.org/10.1590/s0001-37141999000400014.

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Heterotrophic nanoflagellate Pseudobodo tremulans (4.8 to 7.0 µm) and heterotrophic bacteria, isolated from coastal waters in Ubatuba, SP, Brazil, were used in experiments to analyze quantitatively the relationships between bacteria and nanoflagellates. The meaning of these results for the role of heterotrophic nanoflagellates in the Ubatuba coastal ecosystem is discussed.
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47

Šantić, Danijela, Vedrana Kovačević, Manuel Bensi, Michele Giani, Ana Vrdoljak Tomaš, Marin Ordulj, Chiara Santinelli, Stefanija Šestanović, Mladen Šolić, and Branka Grbec. "Picoplankton Distribution and Activity in the Deep Waters of the Southern Adriatic Sea." Water 11, no. 8 (August 10, 2019): 1655. http://dx.doi.org/10.3390/w11081655.

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Southern Adriatic (Eastern Mediterranean Sea) is a region strongly dominated by large-scale oceanographic processes and local open-ocean dense water formation. In this study, picoplankton biomass, distribution, and activity were examined during two oceanographic cruises and analyzed in relation to environmental parameters and hydrographic conditions comparing pre and post-winter phases (December 2015, April 2016). Picoplankton density with the domination of autotrophic biomasses was higher in the pre-winter phase when significant amounts of picoaoutotrophs were also found in the meso-and bathy-pelagic layers, while Synechococcus dominated the picoautotrophic group. Higher values of bacterial production and domination of High Nucleic Acid content bacteria (HNA bacteria) were found in deep waters, especially during the post-winter phase, suggesting that bacteria can have an active role in the deep-sea environment. Aerobic anoxygenic phototrophic bacteria accounted for a small proportion of total heterotrophic bacteria but contributed up to 4% of bacterial carbon content. Changes in the picoplankton community were mainly driven by nutrient availability, heterotrophic nanoflagellates abundance, and water mass movements and mixing. Our results suggest that autotrophic and heterotrophic members of the picoplankton community are an important carbon source in the food web in the deep-sea, as well as in the epipelagic layer. Besides, viral lysis may affect the activity of the picoplankton community and enrich the water column with dissolved organic carbon.
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48

Dbwi, I. Ap, D. B. Johnson, and W. I. Kelso. "A study of field drain ochre deposits. 2. The distribution of micro-organisms." Journal of Agricultural Science 108, no. 2 (April 1987): 347–51. http://dx.doi.org/10.1017/s0021859600079363.

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SummarySheathed filamentous bacteria,Leptothrixspp. andGallionellaspp., were observed in ochre samples from sites in England and Wales.Thiobacillus ferrooxidanswas found in acidic samples (pH < 4·0) and in ochre from drainage water of near neutral pH suggesting that it can contribute to ochre formation over a wide range of drainage water pH, Heterotrophic bacteria capable of growing in artificial media of low pH and complexdegrading heterotrophic bacteria were also isolated. Some ochre deposits could be described as either pyritic or filamentous but the majority of samples fell between these extremes and had various combinations ofT. ferrooxidans, sheathed filamentous bacteria and other heterotrophic bacteria.
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49

Allamin, Ibrahim Alkali, Hussaini Shettima, Hafsat Muhammad Abdullahi, Usman Ali Bukar, Amina Umar Faruk, and Abdulhamid Musa Ruwa. "Distribution of Heterotrophic and Nitrogen fixing Rhizobacteria in Irrigation Sites of Lake Alau Borno State Northeastern Nigeria." Journal of Environmental Bioremediation and Toxicology 4, no. 2 (December 31, 2021): 27–30. http://dx.doi.org/10.54987/jebat.v4i2.630.

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This study was conducted to know the population of rhizobacteria in both irrigation and non-irrigation sites of the dam. The dense population of these organism indirectly promote plant growth and development. Five sites (A, B, C, D and E) were used to collect soil samples randomly and transported to the laboratory for analysis. Total heterotrophic bacterial count was done using nutrient agar (NA) and nitrogen fixing bacteria was counted using Ashbey’s media (AM). The result shows that highest number of total heterotrophic bacteria in site C (46.0×106) cfu/g in irrigation site whereas higher count in non-irrigation site was (13.0×106) site D, the nitrogen fixing bacterial count in irrigation site was higher at site E with (12.0×106) and for the non-irrigation site was higher at site D with (14.0×106) The total heterotrophic bacteria isolated in the soil sample are the species of Bacillus alvei, Bacillus alvei, Bacillus cereus, Bacillus cereus, Pseudomonas putida, Klebsiella aeruginosa and Enterobacter aeruginosa. Likewise, the Nitrogen fixing bacteria isolated are the species of Rhizobium leguminosarum, Klebsiella pneumonia, Bacillus lentus, Azotobacter nigricans, Azotobacter tropicalis, Azotobacter spp, and Azotobacter tropicalis. The long history of agricultural activities in the lake area has directly influenced the diversity of microbial population in the area.
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50

Simbolon, L. M., M. S. Ismet, P. Ismiati, A. F. Ilham, and E. S. Srimariana. "Cellulolytic activity at the low temperature of associative bacteria from a seagrass ecosystem." IOP Conference Series: Earth and Environmental Science 1137, no. 1 (January 1, 2023): 012039. http://dx.doi.org/10.1088/1755-1315/1137/1/012039.

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Abstract Cellulase enzymes have been widely used in many industrial activities, such as the production of biofuels, biofertilizers, and bio-decomposers. The usage of cellulase enzymes on an industrial scale usually involves a relatively high temperature. Microorganisms in marine ecosystems are widely known to have the ability to produce cellulase enzymes in various environmental ranges. However, exploring marine cellulolytic bacteria at low temperatures still lacks information. This study aims to determine the cellulolytic activity of bacteria associated with seagrass ecosystems at low temperatures. Cellulolytic activity test used selected bacteria isolates from the seagrass ecosystem (actinobacteria: AA10b, AA11a, AA30a, AB22b; heterotrophic bacterial: HB1.1, HB2.1, HT1.2, HT2.2). The cellulolytic index values were obtained from the clear zone test on CMC 1% medium with congo red staining (actinobacteria) and iodine (heterotrophic bacteria) in different temperature treatments (4°C, 17°C, 20°C, and 40°C). The results showed that all isolates had various cellulolytic index values at different temperatures. There was no bacterial cellulolytic activity at 4°C. However some isolates showed activities at 17°C and increased as the temperature was higher. The highest production of cellulolytic activity occurred at 40°C for both actinobacteria and heterotrophic bacteria isolates. The actinobacteria isolate AA11a had the highest cellulolytic index of 7.00 at 40°C. This study indicates that at low temperatures, associative bacteria from the seagrass ecosystem have considerable cellulolytic activity for further research applications in various industries.
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