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MacCallum, Donna M., Luis Castillo, Kerstin Nather, Carol A. Munro, Alistair J. P. Brown, Neil A. R. Gow, and Frank C. Odds. "Property Differences among the Four Major Candida albicans Strain Clades." Eukaryotic Cell 8, no. 3 (January 16, 2009): 373–87. http://dx.doi.org/10.1128/ec.00387-08.
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ABSTRACT A selection of 43 Candida albicans isolates, chosen to represent the four major strain clades of the species and also intraclade diversity, was screened for their virulence in the murine intravenous challenge model of C. albicans infection, for a range of properties measurable in vitro that might relate to virulence, and for the numbers of midrepeat sequences in genes of the ALS and HYR families. Heterozygosity at the mating type locus and low whole-cell acid phosphatase activity and growth rate at 40°C were found to be significantly positively associated with the most virulent isolates. Acid phosphatase activity and growth in 2 M NaCl were statistically significant variables between clades by univariate analysis. Isolates in different clades also differed significantly in midrepeat sequence alleles of ALS2, ALS4, ALS6, ALS7, ALS9, HYR1, and HYR2. There was no association between the midrepeat alleles of any ALS or HYR gene and the virulence of isolates to mice. Genome-wide transcript profiles of 20 isolates (5 per clade) grown under two conditions showed considerable variation between individual isolates, but only a small number of genes showed statistically significant differential gene expression between clades. Analysis of the expression profiles by overall strain virulence revealed 18 open reading frames differing significantly between isolates of high, intermediate, and low virulence. Four of these genes encoded functions related to phosphate uptake and metabolism. This finding and the significant association between whole-cell acid phosphatase activity and virulence led us to disrupt PHO100, which encodes a predicted periplasmic acid phosphatase. The pho100Δ mutant was mildly but significantly attenuated in terms of survival curves in the mouse model. The study has extended the range of properties known to differ between C. albicans clades and suggests a possible but minor role of phosphate metabolism in the virulence of the species.
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Frick, Claudia, Heiko Steiner, Alex Mazurkiewicz, Ulf Riediger, Monika Rauthe, Thomas Reich, and Annegret Gratzki. "Central European high-resolution gridded daily data sets (HYRAS): Mean temperature and relative humidity." Meteorologische Zeitschrift 23, no. 1 (January 1, 2014): 15–32. http://dx.doi.org/10.1127/0941-2948/2014/0560.
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Skibinski, David A. G., Paul Golby, Yung-Sheng Chang, Frank Sargent, Ralf Hoffman, R. Harper, John R. Guest, Margaret M. Attwood, Ben C. Berks, and Simon C. Andrews. "Regulation of the Hydrogenase-4 Operon of Escherichia coli by the σ54-Dependent Transcriptional Activators FhlA and HyfR." Journal of Bacteriology 184, no. 23 (December 1, 2002): 6642–53. http://dx.doi.org/10.1128/jb.184.23.6642-6653.2002.
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ABSTRACT The hyf locus (hyfABCDEFGHIJ-hyfR-focB) of Escherichia coli encodes a putative 10-subunit hydrogenase complex (hydrogenase-4 [Hyf]); a potential σ54-dependent transcriptional activator, HyfR (related to FhlA); and a putative formate transporter, FocB (related to FocA). In order to gain insight into the physiological role of the Hyf system, we investigated hyf expression by using a hyfA-lacZ transcriptional fusion. This work revealed that hyf is induced under fermentative conditions by formate at a low pH and in an FhlA-dependent fashion. Expression was σ54 dependent and was inhibited by HycA, the negative transcriptional regulator of the formate regulon. Thus, hyf expression resembles that of the hyc operon. Primer extension analysis identified a transcriptional start site 30 bp upstream of the hyfA structural gene, with appropriately located −24 and −12 boxes indicative of a σ54-dependent promoter. No reverse transcriptase PCR product could be detected for hyfJ-hyfR, suggesting that hyfR-focB may be independently transcribed from the rest of the hyf operon. Expression of hyf was strongly induced (∼1,000-fold) in the presence of a multicopy plasmid expressing hyfR from a heterologous promoter. This induction was dependent on low pH, anaerobiosis, and postexponential growth and was weakly enhanced by formate. The hyfR-expressing plasmid increased fdhF-lacZ transcription just twofold but did not influence the expression of hycB-lacZ. Interestingly, inactivation of the chromosomal hyfR gene had no effect on hyfA-lacZ expression. Purified HyfR was found to specifically interact with the hyf promoter/operator region. Inactivation of the hyf operon had no discernible effect on growth under the range of conditions tested. No Hyf-derived hydrogenase or formate dehydrogenase activity could be detected, and no Ni-containing protein corresponding to HyfG was observed.
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Zapletal, David, Petra Jakešová, Eliška Žáková, Vlastimil Šimek, and Eva Straková. "Growth performance, mortality and body and carcass characteristics of rabbit fatteners related to crossbreeding of Mecklenburger Schecke sires with dam line of HYLA rabbits." Czech Journal of Animal Science 65, No. 9. (September 30, 2020): 337–45. http://dx.doi.org/10.17221/192/2020-cjas.
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The aim of the study was to evaluate the effect of crossing Mecklenburger Schecke (MS) males with the maternal commercial line of HYLA rabbits on the growth performance, mortality and body and carcass components of fattened rabbits under intensive farming conditions. The control (C) group consisted of albino crossbred rabbits of the HYLA combination AB sires × CD dams. The tested (T) group (MS sires × HYLA CD dams) consisted of rabbit crosses between the MS sires and the same dam line as in the C group. Rabbits of both groups were raised and fattened under identical nutritional and management conditions. The crossing of MS males with the maternal line of HYLA rabbits led to the acceptable growth performance of rabbits in the T group. The higher slaughter weight of rabbits in the T group as compared to rabbits in the C group (P < 0.01) as associated with the higher weight of hot carcass and higher proportions of fore and intermediate parts of carcass (P < 0.01). On the contrary, HYLA rabbits had a higher proportion of the hind part of carcass (P < 0.001); yields of hind leg meat and musculus longissimus thoracis et lumborum were not influenced by the genotype. However, since higher mortality was found in rabbits of the T group during fattening, it is not possible to recommend the MS breed as a common sire line used under conditions of intensive farming at this moment. Regarding the rabbit sex, slaughtered females showed a higher proportion of liver and a lower dressing percentage associated with the worse carcass compactness compared to males.
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Smith, K. M., L. Gee, and H. R. Bode. "HyAlx, an aristaless-related gene, is involved in tentacle formation in hydra." Development 127, no. 22 (November 15, 2000): 4743–52. http://dx.doi.org/10.1242/dev.127.22.4743.
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Developmental gradients are known to play important roles in axial patterning in hydra. Current efforts are directed toward elucidating the molecular basis of these gradients. We report the isolation and characterization of HyAlx, an aristaless-related gene in hydra. The expression patterns of the gene in adult hydra, as well as during bud formation, head regeneration and the formation of ectopic head structures along the body column, indicate the gene plays a role in the specification of tissue for tentacle formation. The use of RNAi provides more direct evidence for this conclusion. The different patterns of HyAlx expression during head regeneration and bud formation also provide support for a recent version of a reaction-diffusion model for axial patterning in hydra.
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CARAMASCHI, ULISSES, and HELIANNE DE NIEMEYER. "The nomenclatural status of Rana gaimardii Bory de Saint-Vincent, 1828, and Hyla quoyi Bory de Saint-Vincent, 1828 (Anura, Hylidae)." Zootaxa 2655, no. 1 (October 25, 2010): 63. http://dx.doi.org/10.11646/zootaxa.2655.1.5.
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The nomenclatural status of Rana gaimardii Bory de Saint-Vincent, 1828, and Hyla quoyi Bory de Saint-Vincent, 1828 (Anura, Hylidae) are discussed. Rana gaimardii and its combination Hyla gaimardi, a nomen oblitum under Article 23.9.1 of the International Code of Zoological Nomenclature, may be removed from the synonymy of Hypsiboas boans (Linnaeus, 1758) and included in the synonymy of Hypsiboas faber (Wied-Neuwied, 1821) to improve the geographic distribution of both species. Hyla quoyi Bory de Saint-Vincent, 1828, considered by Frost (2010) as incertae sedis in the Hylinae and as a nomen oblitum under the Article 23.9.1 of the International Code of Zoological Nomenclature, if available would replace the well established name Hypsiboas prasinus (Burmeister, 1856); therefore, to improve the nomenclatural status of both species, Hyla quoyi must be included in the synonymy of H. prasinus as a nomen oblitum. Hypsiboas prasinus is a nomen protectum relative to Hyla quoyi, a nomen oblitum.
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Koizumi, Osamu. "Developmental neurobiology of hydra, a model animal of cnidarians." Canadian Journal of Zoology 80, no. 10 (October 1, 2002): 1678–89. http://dx.doi.org/10.1139/z02-134.
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Hydra belongs to the class Hydrozoa in the phylum Cnidaria. Hydra is a model animal whose cellular and developmental data are the most abundant among cnidarians. Hence, I discuss the developmental neurobiology of hydra. The hydra nerve net is a mosaic of neural subsets expressing a specific neural phenotype. The developmental dynamics of the nerve cells are unique. Neurons are produced continuously by differentiation from interstitial multipotent stem cells. These neurons are continuously displaced outwards along with epithelial cells and are sloughed off at the extremities. However, the spatial distribution of each neural subset is maintained. Mechanisms related to these phenomena, i.e., the position-dependent changes in neural phenotypes, are proposed. Nerve-net formation in hydra can be examined in various experimental systems. The conditions of nerve-net formation vary among the systems, so we can clarify the control factors at the cellular level by comparing nerve-net formation in different systems. By large-scale screening of peptide signal molecules, peptide molecules related to nerve-cell differentiation have been identified. The LPW family, composed of four members sharing common N-terminal L(or I)PW, inhibits nerve-cell differentiation in hydra. In contrast, Hym355 (FPQSFLPRG-NH3) activates nerve differentiation in hydra. LPWs are epitheliopeptides, whereas Hym355 is a neuropeptide. In the hypostome of hydra, a unique neuronal structure, the nerve ring, is observed. This structure shows the nerve association of neurites. Exceptionally, the tissue containing the nerve ring shows no tissue displacement during the tissue flow that involves the whole body. The neurons in the nerve ring show little turnover, although nerve cells in all other regions turn over continuously. These associations and quiet dynamics lead me to think that the nerve ring has features similar to those of the central nervous system in higher animals.
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DARMER, Dorothea, Frank HAUSER, Hans-Peter NOTHACKER, Thomas C. G. BOSCH, Michael WILLIAMSON, and Cornelis J. P. GRIMMELIKHUIJZEN. "Three different prohormones yield a variety of Hydra-RFamide (Arg-Phe-NH2) neuropeptides in Hydra magnipapillata." Biochemical Journal 332, no. 2 (June 1, 1998): 403–12. http://dx.doi.org/10.1042/bj3320403.
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The freshwater polyp Hydra is the most frequently used model for the study of development in cnidarians. Recently we isolated four novel Arg-Phe-NH2 (RFamide) neuropeptides, the Hydra-RFamides I–IV, from Hydra magnipapillata. Here we describe the molecular cloning of three different preprohormones from H. magnipapillata, each of which gives rise to a variety of RFamide neuropeptides. Preprohormone A contains one copy of unprocessed Hydra-RFamide I (QWLGGRFG), II (QWFNGRFG), III/IV [(KP)HLRGRFG] and two putative neuropeptide sequences (QLMSGRFG and QLMRGRFG). Preprohormone B has the same general organization as preprohormone A, but instead of unprocessed Hydra-RFamide III/IV it contains a slightly different neuropeptide sequence [(KP)HYRGRFG]. Preprohormone C contains one copy of unprocessed Hydra-RFamide I and seven additional putative neuropeptide sequences (with the common N-terminal sequence QWF/LSGRFGL). The two Hydra-RFamide II copies (in preprohormones A and B) are preceded by Thr residues, and the single Hydra-RFamide III/IV copy (in preprohormone A) is preceded by an Asn residue, confirming that cnidarians use unconventional processing signals to generate neuropeptides from their precursor proteins. Southern blot analyses suggest that preprohormones A and B are each coded for by a single gene, whereas one or possibly two closely related genes code for preprohormone C. Northern blot analyses and in situ hybridizations show that the gene coding for preprohormone A is expressed in neurons of both the head and foot regions of Hydra, whereas the genes coding for preprohormones B and C are specifically expressed in neurons of different regions of the head. All of this shows that neuropeptide biosynthesis in the primitive metazoan Hydra is already rather complex.
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Nykolay, Alice, and Aiman Shahid. "Immortal Hydra as a Model Organism for Metal Toxicity Studies." Sciential - McMaster Undergraduate Science Journal, no. 2 (March 29, 2019): 2–8. http://dx.doi.org/10.15173/sciential.v1i2.2136.
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Toxicology is an interdisciplinary scientific field that explores the impact, epidemiology, and treatment regimens for exposure to various toxic compounds and elements. Many toxicants such as metals have not yet been comprehensively examined, and a plethora of metal-related conditions are currently untreatable. Hydra is an immortal freshwater organism that serves as an excellent model for toxicity studies due to its natural availability, anatomical simplicity, yet comparatively complex physiology. This review will examine the significance of hydra toxicity studies, outline current experimental designs, as well as summarize the most commonly tested metals. Altogether, comprehensive toxicity studies on Hydra might provide promising breakthroughs in the understanding of toxicity-related physiology, and can be applied to clinical research and practice to ultimately improve health and wellbeing of those affected by metal-related disorders.
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Schlaepfer, D. D., H. R. Bode, and H. T. Haigler. "Distinct cellular expression pattern of annexins in Hydra vulgaris." Journal of Cell Biology 118, no. 4 (August 15, 1992): 911–28. http://dx.doi.org/10.1083/jcb.118.4.911.
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The annexins are a structurally related family of Ca2+ and phospholipid binding proteins whose function has not been clearly defined. Further investigations of annexin function may be enhanced by studying simpler organisms that express fewer annexin gene products. We previously characterized annexin XII from the freshwater cnidarian Hydra vulgaris (Schlaepfer, D. D., D. A. Fisher, M. E. Brandt, H. R. Bode, J. Jones, and H. T. Haigler. 1992. J. Biol. Chem. 267:9529-9539). In this report, we detected one other hydra annexin (40 kD) by screening hydra cell extracts with antibodies raised against peptides from highly conserved regions of known annexins. The 40-kD protein was expressed at less than 1% of annexin XII levels. These biochemical studies indicate that hydra contain a very limited number of annexin gene products. The cellular hydra annexin distribution was analyzed by indirect immunofluorescence. Using affinity-purified antibodies to annexin XII, the epithelial battery cells were stained throughout the tentacle. A lower level of annexin XII staining was detected in peduncle region epithelial cells. No other cell types showed detectable annexin XII staining. The anti-peptide antibody that specifically detected the 40-kD hydra annexin, maximally stained the cytoplasm of nematocytes. The immunofluorescent results showed that annexin XII and the 40-kD annexin were not co-expressed in the same cells. Since the hydra annexins localized to specific subsets of the total hydra cell types, it is likely that these proteins perform specialized biological roles, and not general "housekeeping" functions which are part of the essential molecular machinery of all cells.
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Schaible, Ralf, Alexander Scheuerlein, Maciej J. Dańko, Jutta Gampe, Daniel E. Martínez, and James W. Vaupel. "Constant mortality and fertility over age in Hydra." Proceedings of the National Academy of Sciences 112, no. 51 (December 7, 2015): 15701–6. http://dx.doi.org/10.1073/pnas.1521002112.
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Senescence, the increase in mortality and decline in fertility with age after maturity, was thought to be inevitable for all multicellular species capable of repeated breeding. Recent theoretical advances and compilations of data suggest that mortality and fertility trajectories can go up or down, or remain constant with age, but the data are scanty and problematic. Here, we present compelling evidence for constant age-specific death and reproduction rates in Hydra, a basal metazoan, in a set of experiments comprising more than 3.9 million days of observations of individual Hydra. Our data show that 2,256 Hydra from two closely related species in two laboratories in 12 cohorts, with cohort age ranging from 0 to more than 41 y, have extremely low, constant rates of mortality. Fertility rates for Hydra did not systematically decline with advancing age. This falsifies the universality of the theories of the evolution of aging that posit that all species deteriorate with age after maturity. The nonsenescent life history of Hydra implies levels of maintenance and repair that are sufficient to prevent the accumulation of damage for at least decades after maturity, far longer than the short life expectancy of Hydra in the wild. A high proportion of stem cells, constant and rapid cell turnover, few cell types, a simple body plan, and the fact that the germ line is not segregated from the soma are characteristics of Hydra that may make nonsenescence feasible. Nonsenescence may be optimal because lifetime reproduction may be enhanced more by extending adult life spans than by increasing daily fertility.
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Yadav, Mukesh Kumar, Sung-Won Chae, Kyeongsoon Park, and Jae-Jun Song. "Hyaluronic Acid Derived from Other Streptococci SupportsStreptococcus pneumoniae In VitroBiofilm Formation." BioMed Research International 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/690217.
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We investigate the role of hyaluronic acid (HA) onS. pneumoniae in vitrobiofilm formation and evaluate gene expressions of virulence and/or biofilm related genes. Biofilms were grown in medium supplied with HA derived from capsule ofStreptococcus equi. The biomasses of biofilms were detected by crystal-violet (CV) microtiter plate assay, and the morphology was viewed under scanning electron microscope (SEM). The gene expressions were assessed by relative quantitative RT-PCR. The results showed that the HA support pneumococcal growth in planktonic form and within biofilms. The CV-microtiter plate assay detected significantly increased biofilm growth in medium containing HA. The SEM analysis revealed thick and organized biofilms in positive control and HA supplemented medium. ThenanA,nanB,bgaA,strH,luxS,hysA,ugl, and PST-EIIA encoding genes were significantly upregulated in the planktonic cells grown in presence of HA, while thelytAandcomAgenes were downregulated. Similarly theluxS,hysA,ugl, and PST-EIIA encoding genes were significantly upregulated by more than 2-folds in HA biofilms. The results of this study indicate that the HA derived from capsule ofS. equisupports pneumococcal growth in planktonic state and within biofilms and upregulated virulence and biofilm related genes.
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Liu, Li, Weiwei Tao, Wenjia Pan, Li Li, Qiong Yu, Dawei Zhang, and Jun Jiang. "Hydroxysafflor Yellow A Promoted Bone Mineralization and Inhibited Bone Resorption Which Reversed Glucocorticoids-Induced Osteoporosis." BioMed Research International 2018 (July 5, 2018): 1–8. http://dx.doi.org/10.1155/2018/6762146.
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Glucocorticoids intake is the most common cause of secondary osteoporosis. Clinical studies have shown that 50% patients develop glucocorticoids-induced osteoporosis (GCIOP) after taking glucocorticoids for more than 6 months. Hydroxysafflor yellow A (HYA) is one main active ingredient in Carthamus tinctorius L. Previous studies have shown that HYA promoted bone marrow mesenchymal stem cells to differentiate into osteoblasts which promoted bone formation. Therefore, we speculated that HYA has a therapeutic effect on GCIOP. However, there is no in vivo evidence about the anti-GCIOP effect of HYA. In this paper, the effect of HYA (0.1, 1.0, and 10.0 μM) on bone formation in normal zebrafish was investigated firstly. Secondly, the reversal effect of HYA on GCIOP was also evaluated by zebrafish model. It is demonstrated that HYA not only promoted bone formation in normal zebrafish (compared to Control group), but also reversed glucocorticoid induced bone loss (compared to Prednisolone group) according to the intervention of HYA in upregulating the area of mineralized bones (p < 0.01), increasing cumulative optical density (p < 0.01), promoting bone formation related gene expression (AKP, Type I, Runx2, OPG, and OCN, p < 0.01), inhibiting bone resorption related gene expression (TRACP, p < 0.01), and elevating whole-body trace mineral elements (Ca, P, K, Mg, Zn, and Fe) levels (p < 0.01). In conclusion, HYA had the potential to prevent and heal GCIOP by promoting bone mineralization, osteoblasts viability, and bone collagen expression and inhibiting bone resorption.
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Massaro, Fernanda Cristina, Natalia Felix Negreiros, and Odete Rocha. "A search for predators and food selectivity of two native species of Hydra (Cnidaria: Hydrozoa) from Brazil." Biota Neotropica 13, no. 2 (June 2013): 35–40. http://dx.doi.org/10.1590/s1676-06032013000200003.
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The Hydra is the most common representative of freshwater cnidarians. In general, it is found in freshwaters on every continent, with the exception of Antarctica. The aim of the present study is to gather biological and ecological data on aspects of two species of Hydra native to Brazil: Hydra viridissima and Hydra salmacidis. Predation and food selectivity experiments were performed to assess the possible predators and the prey preferences, respectively, of the two species. The results indicate that the two species of Hydra were not consumed by any of the predators that were tested, which are typical predators of invertebrates in freshwater: nymphs of Odonata Anisoptera and the phantom midge larvae of Chaoborus sp. (Insecta), adults of Copepoda Cyclopoida (Crustacea) and the small fish Poecilia reticulata. It was observed that the smaller Hydra, H. viridissima, positively selected the nauplii and copepodites of calanoid copepods and small cladocerans and rejected large prey, such as the adults of calanoid copepods and ostracods. The larger H. salmacidis, besides the nauplii and copepodites of the calanoid copepods and small cladocerans, also positively selected the large adults of the calanoid copepods. It can be concluded that both H. viridissima and H. salmacidis are most likely preyed on little or not preyed on at all in many freshwater bodies, as they are top predators in the food chain. At the same time, they are efficient predators, and a positive relationship was observed between the prey size and the Hydra species size. Food selectivity was related to prey size as well as other prey characteristics, such as carapace thickness and swimming efficiency.
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Bosch, Thomas C. G., and Konstantin Khalturin. "Patterning and cell differentiation in Hydra: novel genes and the limits to conservation." Canadian Journal of Zoology 80, no. 10 (October 1, 2002): 1670–77. http://dx.doi.org/10.1139/z02-129.
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In the last few years more than 100 genes have been identified from Hydra, and well over 80 have been characterized. Since most genes are homologs of genes found in bilaterians, the genetic mechanisms for axial patterning and cell differentiation are evolutionarily conserved. This constitutes something of a paradox. If key developmental-control genes are the same in Hydra and all other organisms, how does one account for the marked differences in development and morphology of the different animal groups? How are taxon-specific features encoded? To examine whether in Hydra, in addition to conserved mechanisms, there are genetic features that control uniquely taxon-specific (Hydra/Hydrozoa/Cnidaria) aspects, we used an experimental strategy that does not require sequence data from related taxa. By means of this unbiased ("knowledge-independent") approach we have identified genes from Hydra encoding signal molecules and effector genes with no sequence similarity to genes in other organisms. When tested functionally, the novel genes were found to be essential for axial patterning and differentiation of Hydra-specific characteristics. Experimental analysis of the cis-regulatory apparatus of these novel genes reveals target sites for novel trans-acting factors. The use of unbiased screening approaches for several other organisms also reveals a large number of novel and taxon-specific genes of as yet unknown function. Thus, comparative data alone may not be sufficient for gaining a full understanding of the development of taxon-specific characteristics.
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Kim, Lee, and Yeo. "Reduction in Toxicity of Nano-Ag-Polyvinyl-pyrrolidone Using Hydra Proteins and Peptides during Zebrafish Embryogenesis." Nanomaterials 9, no. 9 (August 27, 2019): 1210. http://dx.doi.org/10.3390/nano9091210.
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Hydra magnipapillata cells reduce the toxicity of silver nanomaterials to zebrafish (Danio rerio) embryos. In this study, we investigated whether Hydra protein (HP) and Hydra basal disc peptide (Hym176) materials reduce nano-Ag-polyvinylpyrrolidone (N-Ag-PVP) toxicity during embryogenesis of the nanosensitive organism zebrafish. Protein (HP) was extracted from Hydra, and peptide (Hym176) was extracted from the hydra basal disc, which is attractive to nanomaterials and related to the immune system. The experimental conditions were exposure to N-Ag-PVP, HP, N-Ag-PVP+HP, Hym176, or N-Ag-PVP+Hym176 during embryo development. N-Ag-PVP+HP group showed lower toxicity than N-Ag-PVP group. In addition, in the N-Ag-PVP+HP group formed aggregated nanomaterials (≥200 nm size) through electrostatic bonding. In the gene expression profile, HP group differed in gene expression profile compared the other experimental groups and it was no genetic toxicity. HP showed a tendency to reduce side effects and abnormal gene expression produced by N-Ag-PVP with no evidence of inherent toxicity. Considering the potential nanotoxicity effects of released nanomaterials on the ecosystem, the reduction of nanotoxicity observed with HP natural materials should be regarded with great interest in terms of the overall health of the ecosystem.
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Razafimaharo, Christène, Stefan Krähenmann, Simona Höpp, Monika Rauthe, and Thomas Deutschländer. "New high-resolution gridded dataset of daily mean, minimum, and maximum temperature and relative humidity for Central Europe (HYRAS)." Theoretical and Applied Climatology 142, no. 3-4 (September 26, 2020): 1531–53. http://dx.doi.org/10.1007/s00704-020-03388-w.
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Abstract This study presents daily high-resolution (5 km × 5 km) grids of mean, minimum, and maximum temperature and relative humidity for Germany and its catchment areas, from 1951 to 2015. These observational datasets (HYRAS) are based upon measurements gathered for Germany and its neighbouring countries, in total more than 1300 stations, gridded in two steps: first, the generation of a background field, using non-linear vertical temperature profiles, and then an inverse distance weighting scheme to interpolate the residuals, subsequently added onto the background field. The modified Euclidian distances used integrate elevation, distance to the coast, and urban heat island (UHI) effect. A direct station-grid comparison and cross-validation yield low errors for the temperature grids over most of the domain and greater deviations in more complex terrain. The interpolation of relative humidity is more uncertain due to its inherent spatial inhomogeneity and indirect derivation using dew point temperature. Compared with other gridded observational datasets, HYRAS benefits from its high resolution and captures complex topographic effects. HYRAS improves upon its predecessor by providing datasets for additional variables (minimum and maximum temperature), integrating temperature inversions, maritime influence and UHI effect, and representing a larger area. With a long-term observational dataset of multiple meteorological variables also including precipitation, various climatological analyses are possible. We present long-term historical climate trends and relevant indices of climate extremes, pointing towards a significantly warming climate over Germany, with no significant change in total precipitation. We also evaluate extreme events, specifically the summer heat waves of 2003 and 2015.
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Yan, L., G. H. Pollock, H. Nagase, and M. P. Sarras. "A 25.7 × 10(3) M(r) hydra metalloproteinase (HMP1), a member of the astacin family, localizes to the extracellular matrix of Hydra vulgaris in a head-specific manner and has a developmental function." Development 121, no. 6 (June 1, 1995): 1591–602. http://dx.doi.org/10.1242/dev.121.6.1591.
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Hydra extracellular matrix (ECM) is composed of a number of components seen in vertebrate ECM such as laminin, type IV collagen, fibronectin, and heparan sulfate proteoglycan. A number of functional studies have shown that hydra ECM plays an important role in pattern formation and morphogenesis of this simple metazoan. The present study was designed to identify matrix degrading proteinases in hydra and determine their potential function in hydra morphogenesis. Using SDS-PAGE gelatin-zymography, five gelatinolytic bands were identified with relative molecular masses of 67 × 10(3), 51–58 × 10(3) (a triplet) and 25–29 × 10(3), respectively. Inhibition studies indicated that all of these gelatinases were metalloproteinases. Gelatin-zymography indicated that there was a differential distribution of these gelatinases along the longitudinal axis of hydra, with the 67 × 10(3) M(r) gelatinase being concentrated in the body column, while the 51–58 × 10(3) M(r) gelatinase triplet and the 25–29 × 10(3) M(r) gelatinase concentrated in the head region. Purification procedures were successfully developed for the 25–29 × 10(3) M(r) metalloproteinase which has been termed hydra metalloproteinase 1 (HMP1) and which appeared as a single band with a SDS-PAGE mobility of 25.7 × 10(3) M(r). The N-terminal sequence of purified HMP1 indicated that it has structural homology with metalloproteinases that belong to the astacin family. Subsequent cloning and sequencing of cDNA clones confirmed the identification of HMP1 as an astacin-like metalloproteinase. Immunocytochemical studies with antibodies generated against the purified enzyme and to a synthetic peptide indicated that HMP1 was localized to the ECM of tentacles. Functional studies were performed in which purified HMP1, anti-HMP1 IgG, or suspected substrates of HMP1 (e.g. growth factors such as TGF-beta 1) were introduced into the interepithelial compartment of hydra using a ‘DMSO loading’ procedure. These studies indicated that HMP1 has a functional role during a number of developmental processes such as head regeneration and cell differentiation/transdifferentiation of tentacle battery cells.
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Dahl, Inger Marie S., Ingemar Turesson, Erik Holmberg, and Karin Lilja. "Serum Hyaluronan in Patients With Multiple Myeloma: Correlation With Survival and Ig Concentration." Blood 93, no. 12 (June 15, 1999): 4144–48. http://dx.doi.org/10.1182/blood.v93.12.4144.
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Abstract Serum from 386 myeloma patients were analyzed for serum hyaluronan (HYA) at diagnosis. Median age was 68 years (range, 32 to 87 years). The distribution of Ig classes was typical (58% IgG, 21% IgA, 1% IgD, and 20% light chain disease). The patients comprised 58% in stage III, 33% in stage II, and 9% in stage I. The majority (82%) had HYA values within an intermediate range (10 to 120 μg/L), 13% had high values (>120 μg/L), and 5% had abnormally low values (0 to 9 μg/L). For the first time, a patient group with abnormally low HYA serum values is reported. An inverse correlation between survival and HYA serum level was found (P = .015). When tested separately, patients with abnormally low or high HYA values had significantly shorter median survival (21.1 and 19.7 months, respectively) than those with an intermediate HYA concentration (32.6 months; P = .005). Patients with abnormally low or high HYA levels had more advanced disease as judged by staging and biochemical markers. Interestingly, there was an inverse correlation between the HYA value and the M-component concentration in serum. Fifty percent of patients with abnormally low HYA values had IgA myelomas. In conclusion, the serum concentration of HYA may be of prognostic value in selected cases of multiple myeloma. Further studies will be performed to elucidate possible explanations for our findings, especially those related to the HYA cell surface binding proteins.
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Dahl, Inger Marie S., Ingemar Turesson, Erik Holmberg, and Karin Lilja. "Serum Hyaluronan in Patients With Multiple Myeloma: Correlation With Survival and Ig Concentration." Blood 93, no. 12 (June 15, 1999): 4144–48. http://dx.doi.org/10.1182/blood.v93.12.4144.412a36_4144_4148.
Full textAbstract:
Serum from 386 myeloma patients were analyzed for serum hyaluronan (HYA) at diagnosis. Median age was 68 years (range, 32 to 87 years). The distribution of Ig classes was typical (58% IgG, 21% IgA, 1% IgD, and 20% light chain disease). The patients comprised 58% in stage III, 33% in stage II, and 9% in stage I. The majority (82%) had HYA values within an intermediate range (10 to 120 μg/L), 13% had high values (>120 μg/L), and 5% had abnormally low values (0 to 9 μg/L). For the first time, a patient group with abnormally low HYA serum values is reported. An inverse correlation between survival and HYA serum level was found (P = .015). When tested separately, patients with abnormally low or high HYA values had significantly shorter median survival (21.1 and 19.7 months, respectively) than those with an intermediate HYA concentration (32.6 months; P = .005). Patients with abnormally low or high HYA levels had more advanced disease as judged by staging and biochemical markers. Interestingly, there was an inverse correlation between the HYA value and the M-component concentration in serum. Fifty percent of patients with abnormally low HYA values had IgA myelomas. In conclusion, the serum concentration of HYA may be of prognostic value in selected cases of multiple myeloma. Further studies will be performed to elucidate possible explanations for our findings, especially those related to the HYA cell surface binding proteins.
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Martins, Marcio. "Observations on nest dynamics and embryonic and larval development in the nest building gladiator frog, Hyla faber." Amphibia-Reptilia 14, no. 4 (1993): 411–21. http://dx.doi.org/10.1163/156853893x00101.
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AbstractNests and larval development of the nest building gladiator frog, Hyla faber were studied in southeastern Brazil, during the rainy season of 1988-1989. Nests were built at the pond margins, exclusively by males, and varied in shape, size, and composition in relation to the substrate. Nests were used by 1-4 individual males and housed larvae for a mean of 26 days; 0-6 egg clutches were deposited in a nest. Larvae from individual clutches stayed inside the nests for 8-38 days. Embryonic development occurred within the first 210 h after fertilization and larval development, inside an enclosure installed in a pond, lasted over 8 months. Mortality inside the nests was due to nest water evaporation and/or drainage, to eggs sinking in the first hours after fertilization, or to predation by aquatic insects. Slow larval development in Hyla faber seems to be related to breeding in permanent ponds. Nest building in Hyla faber and related species may have evolved from the habit of using natural depressions for egg laying observed in other morphologically similar species.
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Kim, Geun Joong, Dong Eun Lee, and Hak-Sung Kim. "Functional Expression and Characterization of the Two Cyclic Amidohydrolase Enzymes, Allantoinase and a Novel Phenylhydantoinase, from Escherichia coli." Journal of Bacteriology 182, no. 24 (December 15, 2000): 7021–28. http://dx.doi.org/10.1128/jb.182.24.7021-7028.2000.
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ABSTRACT A superfamily of cyclic amidohydrolases, including dihydropyrimidinase, allantoinase, hydantoinase, and dihydroorotase, all of which are involved in the metabolism of purine and pyrimidine rings, was recently proposed based on the rigidly conserved structural domains in identical positions of the related enzymes. With these conserved domains, two putative cyclic amidohydrolase genes fromEscherichia coli, flanked by related genes, were identified and characterized. From the genome sequence of E. coli, theallB gene and a putative open reading frame, tentatively designated as a hyuA (for hydantoin-utilizing enzyme) gene, were predicted to express hydrolases. In contrast to allB, high-level expression of hyuA in E. coli of a single protein was unsuccessful even under various induction conditions. We expressed HyuA as a maltose binding protein fusion protein and AllB in its native form and then purified each of them by conventional procedures. allB was found to encode a tetrameric allantoinase (453 amino acids) which specifically hydrolyzes the purine metabolite allantoin to allantoic acid. Another open reading frame, hyuA, located near 64.4 min on the physical map and known as a UUG start, coded for d-stereospecific phenylhydantoinase (465 amino acids) which is a homotetramer. As a novel enzyme belonging to a cyclic amidohydrolase superfamily, E. coli phenylhydantoinase exhibited a distinct activity toward the hydantoin derivative with an aromatic side chain at the 5′ position but did not readily hydrolyze the simple cyclic ureides. The deduced amino acid sequence of the novel phenylhydantoinase shared a significant homology (>45%) with those of allantoinase and dihydropyrimidinase, but its functional role still remains to be elucidated. Despite the unclear physiological function of HyuA, its presence, along with the allantoin-utilizing AllB, strongly suggested that the cyclic ureides might be utilized as nutrient sources in E. coli.
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Shenk, M. A., H. R. Bode, and R. E. Steele. "Expression of Cnox-2, a HOM/HOX homeobox gene in hydra, is correlated with axial pattern formation." Development 117, no. 2 (February 1, 1993): 657–67. http://dx.doi.org/10.1242/dev.117.2.657.
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Cnox-2 is a HOM/HOX homeobox gene that we have identified in the simple metazoan Hydra vulgaris (Cnidaria: Hydrozoa). Cnox-2 is most closely related to anterior members of the Antennapedia gene complex from Drosophila, with the greatest similarity to Deformed. The Cnox-2 protein is expressed in the epithelial cells of adult hydra polyps in a region-specific pattern along the body axis, at a low level in the head and at a high level in the body column and the foot. The expression pattern of Cnox-2 is consistent with a role in axial pattern formation. Alteration of hydra axial patterning by treatment with diacylglycerol (DAG) results in an increase of head activation down the body column and in a coordinate reduction of Cnox-2 expression in epithelial cells in ‘head-like’ regions. These results suggest that Cnox-2 expression is negatively regulated by a signaling pathway acting through protein kinase C (PKC), and that the varying levels of expression of Cnox-2 along the body axis have the potential to result in differential gene expression which is important for hydra pattern formation.
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Krishnamurthy, Meena, Shen‐yi Liao, Monique Deveaux, and Maggie Dalecki. "The Underrepresentation of Women in Prestigious Ethics Journals." Hypatia 32, no. 4 (2017): 928–39. http://dx.doi.org/10.1111/hypa.12351.
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The main goal of this study is to determine whether women are underrepresented in prestigious ethics journals relative to their representation in the field of ethics. Our study proceeds in three steps. Step one: we estimate the percentage of women who specialize in ethics. Step two: we estimate the percentage of articles in prestigious ethics journals that are authored by women. Step three: we examine whether there is any difference between the percentage of women who specialize in ethics and the percentage of articles in prestigious ethics journals that are authored by women. We conclude that women are underrepresented in prestigious ethics journals relative to their representation in the field of ethics.
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Gunzburger, M. S., and J. Travis. "Effects of multiple predator species on green treefrog (Hyla cinerea) tadpoles." Canadian Journal of Zoology 83, no. 7 (July 1, 2005): 996–1002. http://dx.doi.org/10.1139/z05-093.
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Prey species that occur across a range of habitats may be exposed to variable communities of multiple predator species across habitats. Predicting the combined effects of multiple predators can be complex. Many experiments evaluating the effects of multiple predators on prey confound either variation in predator density with predator identity or variation in relative predator frequency with overall predation rates. We develop a new experimental design of factorial predator combinations that maintains a constant expected predation rate, under the null hypothesis of additive predator effects. We implement this design to evaluate the combined effects of three predator species (bass, aeshnid and libellulid odonate naiads) on mortality rate of a prey species, Hyla cinerea (Schneider, 1799) tadpoles, that occurs across a range of aquatic habitats. Two predator treatments (libellulid and aeshnid + libellulid) resulted in lower tadpole mortality than any of the other predator treatments. Variation in tadpole mortality across treatments was not related to coarse variation in microhabitat use, but was likely due to intraguild predation, which occurred in all predator treatments. Hyla cinerea tadpoles have constant, low survival values when exposed to many different combinations of predator species, and predation rate probably increases linearly with predator density.
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Motamedi, Mina, Laura Lindenthal, Anita Wagner, Margherita Kemper, Jasmin Moneer, Mona Steichele, Alexander Klimovich, Jörg Wittlieb, Marcell Jenewein, and Angelika Böttger. "Apoptosis in Hydra: function of HyBcl-2 like 4 and proteins of the transmembrane BAX inhibitor motif (TMBIM) containing family." International Journal of Developmental Biology 63, no. 6-7 (2019): 259–70. http://dx.doi.org/10.1387/ijdb.180199ab.
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Mechanisms of programmed cell death differ between animals, plants and fungi. In animals, apoptotic cell death depends on caspases and Bcl-2 family proteins. These protein families are only found in multicellular animals, including cnidarians, insects and mammals. In contrast, members of the TMBIM-family of transmembrane proteins are conserved across all eukaryotes. Sequence comparisons of cell death related proteins between phyla indicate strong conservation of the genes involved. However, often it is not known whether this is paralleled by conservation of function. Here we present the first study to support an anti-apoptotic function of Bcl-2 like proteins in the cnidarian Hydra within a physiological context. We used transgenic Hydra expressing GFP-tagged HyBcl-2-like 4 protein in epithelial cells. The protein was localised to mitochondria and able to protect Hydra epithelial cells from apoptosis induced by either the PI(3) kinase inhibitor wortmannin or by starvation. Moreover, we identified members of the TMBIM-family in Hydra including HyBax-Inhibitor-1, HyLifeguard-1a and -1b and HyLifeguard 4. Expressing these TMBIM-family members in Hydra and human HEK cells, we found HyBax-inhibitor-1 protein localised to ER-membranes and HyLifeguard-family members localised to the plasma membrane and Golgi-vesicles. Moreover, HyBax-inhibitor-1 protected human cells from camptothecin induced apoptosis. This work illustrates that the investigated Bcl-2- and TMBIM-family members represent evolutionarily conserved mitochondrial, ER, Golgi and plasma membrane proteins with anti-apoptotic functions. The participation of ER and Golgi proteins in the regulation of programmed cell death might be a very ancient feature.
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Burns, Sean P., Anthony C. Delany, Jielun Sun, Britton B. Stephens, Steven P. Oncley, Gordon D. Maclean, Steven R. Semmer, Joel Schröter, and Johannes Ruppert. "An Evaluation of Calibration Techniques for In Situ Carbon Dioxide Measurements Using a Programmable Portable Trace-Gas Measuring System." Journal of Atmospheric and Oceanic Technology 26, no. 2 (February 1, 2009): 291–316. http://dx.doi.org/10.1175/2008jtecha1080.1.
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Abstract The construction and deployment of a portable trace-gas measurement system (TGaMS) is described. The air-collection system (dubbed HYDRA) collects air samples from 18 different locations and was connected to either one or two LI-COR LI-7000 gas analyzers to measure CO2. An in situ “field calibration” method, that uses four calibration gases with an uncertainty on the order of ±0.1 μmol mol−1 relative to the WMO CO2 mole fraction scale, revealed CO2 output from the LI-7000 had a slightly nonlinear relationship relative to the CO2 concentration of the calibration gases. The sensitivity of the field-calibrated CO2 to different forms of the field-calibration equation is investigated. To evaluate TGaMS performance, CO2 from collocated inlets, portable gas cylinders, and nearby independent CO2 instruments are compared. Results are as follows: 1) CO2 measurements from HYDRA multiple inlets are feasible with a reproducibility of ±0.4 μmol mol−1 (based on the standard deviation of the CO2 difference between collocated inlets when HYDRA was operating with two LI-7000s); 2) CO2 differences among the various field-calibration equations were on the order of ±0.3 μmol mol−1; and 3) comparison of midday hourly CO2 measurements at 30 m AGL between TGaMS and an independent high-accuracy CO2 measurement system (within 300 m of TGaMS) had a median difference and standard deviation of 0.04 ± 0.81 μmol mol−1 over two months.
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Mochizuki, Kazufumi, Hiroko Sano, Satoru Kobayashi, Chiemi Nishimiya-Fujisawa, and T. Fujisawa. "Expression and evolutionary conservation of nanos- related genes in Hydra." Development Genes and Evolution 210, no. 12 (November 21, 2000): 591–602. http://dx.doi.org/10.1007/s004270000105.
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Hartmann, Paulo, Marília Hartmann, and Célio Haddad. "Visual signaling and reproductive biology in a nocturnal treefrog, genus Hyla (Anura: Hylidae)." Amphibia-Reptilia 25, no. 4 (2004): 395–406. http://dx.doi.org/10.1163/1568538042788933.
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AbstractWe investigated reproductive activity, courtship behavior, call structure, body size, clutch size, oviposition site, and reproductive mode of Hyla sp. (aff. ehrhardti). Males called in all months, but showed a peak of activity during the rainy season. Three pair formations were observed and courtship involved stereotyped behavioral sequences, including visual signaling. Males emitted three different vocalization types: advertisement calls, courtship calls, and a vocalization of unknown function. Females attained larger body sizes than males and deposited an average of 74.5 unpigmented eggs per clutch. Early larval stages are aquatic but restricted to water in constructed subterranean nests; subsequent to flooding of nests, exotrophic tadpoles live in ponds or streams. Courtship behavior in Hyla sp. (aff. ehrhardti) is complex and the diverse repertoire of limb movements, exhibited by males, probably provide visual stimuli to females in this nocturnal treefrog. Hyla sp. (aff. ehrhardti) belongs to the H. albomarginata group. Considering the reproductive modes in this group, the complexes of H. albosignata and of H. albofrenata can be considered more close related to each other than to the H. albomarginata complex.
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Martínez-Bas, Ana María, Mathieu Kessler, and Eva Armero. "Relative growth in rabbits: the effects of genetic line, diet and gender." World Rabbit Science 26, no. 3 (September 28, 2018): 201. http://dx.doi.org/10.4995/wrs.2018.7435.
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<p>The relative growth of different parts of the body and tissues was analysed using an allometric model. Animals were crossbred rabbits (males and females) from the mating of commercial lines HYLA-grand parental doe (HY-GPD) female with HYLA Coloured (HY-CO) or Grimaud (GR) males, both selected for the growth rate, or HY-GPD males, selected for weaning weight. They were fed on two different diet, mainly differing in their energy content, and the relative growth of the different parts of their body was assessed. The components with a nearly isometric growth pattern, which grew at the same mean rate as the rest of the body, were skin, chilled carcass and reference carcass; hind legs for retail cuts; and dorsal and carcass length for linear measurements. All allometric coefficients were calculated with respect to the slaughter weight, except percentage of hind leg inter-intramuscular fat (IIMF), which was calculated with respect to the weight of the hind leg. The components that showed early maturing were liver, kidneys, breast and rib viscera for offal and organs; head and breast and ribs for retail cuts; and bone and IIMF percentage of the hind leg. The components with late maturing were forelegs and loin for retail cuts, inguinal, scapular and perirenal fat, meat of the hind leg, and thigh and lumbar circumference length for carcass linear measurements. The GR line showed earlier growth for loin than the maternal HY-GPD line. In addition, the GR and HY-CO lines developed scapular and inguinal fat later than the HY-GPD line. For IIMF percentage, GR presented later growth than HY-CO and HY-GPD. The main effect of the diet was on liver development and on scapular fat: rabbits fed on the high-energy diet showed later liver and scapular fat growth.</p>
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Caro, T. M., and R. M. Alawi. "Comparative Aspects of Behavioural Development in Two Species of Free-Living Hyrax." Behaviour 95, no. 1-2 (1985): 87–109. http://dx.doi.org/10.1163/156853985x00064.
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AbstractFour measures of play behaviour of two species of sympatrically living hyrax Heterohyrax brucei and Procavia johnstoni, were studied on three rocky outcrops or kopjes in the Serengeti National Park, Tanzania. The amount of play shown by young of both species, born in 1981, declined during the study. Procavia played at a significantly higher rate than did Heterohyrax throughout this period. This was true even after differences in species' activity were taken into account. Procavia did not show higher rates of behaviour because they had more conspecifics with which to interact. The young of both species of hyrax played with members of the other species; Procavia significantly more so than Heterohyrax. The high rates of interspecific play in Procavia could be explained by their relatively low numbers compared to Heterohyrax on one kopje, but on the other two kopjes they appeared to actively seek out interactions with Heterohyrax. Interspecific differences in the behaviour of young of the two hyrax species were then related to interspecific differences in their adult behaviour. Adult Procavia exhibited higher scores than adult Heterohyrax on three measures of behaviour, reflecting corresponding differences in the play of the young of these species. These differences were found even when adult behavioural scores had been standardised for activity. Furthermore, adult Procavia showed more interspecific behaviour than adult Heterohyrax; a result similar to that found in the play of the young of the two species of hyrax.
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Bosch, T. C., T. F. Unger, D. A. Fisher, and R. E. Steele. "Structure and expression of STK, a src-related gene in the simple metazoan Hydra attenuata." Molecular and Cellular Biology 9, no. 10 (October 1989): 4141–51. http://dx.doi.org/10.1128/mcb.9.10.4141.
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Both cDNA clones and a genomic DNA clone encoding a 509-amino-acid protein that is 64% similar to chicken pp60c-src were isolated from the simple metazoan Hydra attenuata. We have designated this gene STK, for src-type kinase. Features of the amino acid sequence of the protein encoded by the STK gene suggest that it is likely to be myristoylated and regulated by phosphorylation in a manner similar to that found for pp60c-src. The genomic sequence encoding the protein was found to be interrupted by at least two introns, one of which was located in a position identical to that of one of the introns in the chicken src gene. The STK gene was expressed during early development of H. attenuata and at high levels in the epithelial cells of adult polyps. Probing of Hydra proteins with an antibody to phosphotyrosine indicated that the major phosphotyrosine-containing protein in H. attenuata may be the STK protein itself. H. attenuata is the simplest organism from which a protein-tyrosine kinase gene has been isolated. The presence of such a gene in the evolutionarily ancient phylum Cnidaria suggests that protein-tyrosine kinase genes arose concomitantly with or shortly after the appearance of multicellular organisms.
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Bosch, T. C., T. F. Unger, D. A. Fisher, and R. E. Steele. "Structure and expression of STK, a src-related gene in the simple metazoan Hydra attenuata." Molecular and Cellular Biology 9, no. 10 (October 1989): 4141–51. http://dx.doi.org/10.1128/mcb.9.10.4141-4151.1989.
Full textAbstract:
Both cDNA clones and a genomic DNA clone encoding a 509-amino-acid protein that is 64% similar to chicken pp60c-src were isolated from the simple metazoan Hydra attenuata. We have designated this gene STK, for src-type kinase. Features of the amino acid sequence of the protein encoded by the STK gene suggest that it is likely to be myristoylated and regulated by phosphorylation in a manner similar to that found for pp60c-src. The genomic sequence encoding the protein was found to be interrupted by at least two introns, one of which was located in a position identical to that of one of the introns in the chicken src gene. The STK gene was expressed during early development of H. attenuata and at high levels in the epithelial cells of adult polyps. Probing of Hydra proteins with an antibody to phosphotyrosine indicated that the major phosphotyrosine-containing protein in H. attenuata may be the STK protein itself. H. attenuata is the simplest organism from which a protein-tyrosine kinase gene has been isolated. The presence of such a gene in the evolutionarily ancient phylum Cnidaria suggests that protein-tyrosine kinase genes arose concomitantly with or shortly after the appearance of multicellular organisms.
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Kurz, E. M., T. W. Holstein, B. M. Petri, J. Engel, and C. N. David. "Mini-collagens in hydra nematocytes." Journal of Cell Biology 115, no. 4 (November 15, 1991): 1159–69. http://dx.doi.org/10.1083/jcb.115.4.1159.
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We have isolated and characterized four collagen-related c-DNA clones (N-COL 1, N-COL 2, N-COL 3, N-COL 4) that are highly expressed in developing nematocytes in hydra. All four c-DNAs as well as their corresponding transcripts are small in size (600-1,000 bp). The deduced amino acid sequences show that they contain a central region consisting of 14 to 16 Gly-X-Y triplets. This region is flanked amino-terminal by a stretch of 14-23 proline residues and carboxy-terminal by a stretch of 6-9 prolines. At the NH2- and COOH-termini are repeated patterns of cysteine residues that are highly conserved between the molecules. A model is proposed which consists of a central stable collagen triple helix of 12-14 nm length from which three 9-22 nm long polyproline II type helices emerge at both ends. Disulfide linkage between cysteine-rich segments in these helices could lead to the formation of oligomeric network structures. Electrophoretic characterization of nematocyst extracts allows resolution of small proline-rich polypeptides that correspond in size to the cloned sequences.
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Grens, A., H. Shimizu, S. A. Hoffmeister, H. R. Bode, and T. Fujisawa. "The novel signal peptides, pedibin and Hym-346, lower positional value thereby enhancing foot formation in hydra." Development 126, no. 3 (February 1, 1999): 517–24. http://dx.doi.org/10.1242/dev.126.3.517.
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Signaling molecules affecting patterning processes are usually proteins and rarely peptides. Two novel peptides, pedibin and Hym-346, that are closely related to one another have been isolated from Hydra vulgaris and Hydra magnipapillata. Several experiments indicate that both cause a reduction in the positional value gradient, the principle patterning process governing the maintenance of form in the adult hydra. The peptides cause an increase in the rate of foot regeneration following bisection of the body column. Treatment of animals with either peptide for an extended period of time resulted in an apical extension of the range of expression of CnNk-2 along the body column. Such an extension is correlated with a decrease in positional value. Transplantation of tissue treated with Hym-346 results in an increase in the fraction forming feet, and aggregates derived from Hym-346 tissue form more feet and fewer heads. The latter two experiments provide a direct measure of the lowering of positional value in the treated tissue. These results suggest that peptides play signaling roles in patterning processes in cnidaria and, plausibly, in more complex metazoans as well.
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Aaronson, M., G. D. Bothun, K. G. Budge, J. A. Dawe, R. J. Dickens, P. J. Hall, J. R. Lucey, et al. "Large Peculiar Velocities in the Hydra Centaurus Supercluster." Symposium - International Astronomical Union 130 (1988): 185–89. http://dx.doi.org/10.1017/s0074180900136010.
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Six clusters forming part of the Hydra-Cen Supercluster and its extension on the opposite side of the galactic plane are under study at 21 cm with the Parkes radiotelescope. The infrared Tully-Fisher relation is used to determine the relative distances of the clusters. These clusters exhibit significant and generally positive peculiar velocities ranging from essentially zero for the Hydra cluster to as much as 1000 km/sec for the Pavo and Centaurus clusters. An upper limit of 500 km/sec was previously found in the study of clusters accessible from Arecibo. Data collection is not yet complete, however, and is further subject to unstudied systematic errors due to present reliance on photographic galaxy diameters. Nevertheless, these preliminary results support the notion of a large scale (and presumably gravitationally) disturbed velocity field in the second and third quadrants of the supergalactic plane.
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Mable, Barbara K., and Leslie A. Rye. "Developmental abnormalities in triploid hybrids between tetraploid and diploid tree frogs (genus Hyla)." Canadian Journal of Zoology 70, no. 10 (October 1, 1992): 2072–76. http://dx.doi.org/10.1139/z92-279.
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Crosses between tetraploid female grey tree frogs, Hyla versicolor, and diploid males of the same genus may provide information on developmental differences between the parental species. Crosses with Hyla cinerea males in 1988 produced a large number of vigorous offspring, but abnormalities in eye development indicated some incompatibility of the parental genomes. The degree of eye development of the hybrids varied, ranging from completely absent to fully functional. Repetition of this cross combination in 1989 resulted in similar variation in eye formation. Histological sections through developing eyes indicated that the abnormalities may be related to improper formation of the cornea, improper orientation of the lens, or lack of lens induction. This may reflect differences in the timing of development between the two parental species.
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Singh, Jakeet. "Religious Agency and the Limits of Intersectionality." Hypatia 30, no. 4 (2015): 657–74. http://dx.doi.org/10.1111/hypa.12182.
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This article probes the relative absence of religion within discussions of intersectionality, and begins to address this absence by bringing intersectionality studies into conversation with another significant field within feminist theory: the study of religious women's agency. Although feminist literatures on intersectionality and religious women's agency have garnered a great deal of scholarly attention, these two bodies of work have rarely been engaged together. After surveying both fields, I argue that research on religious women's agency not only exposes an ambiguity at the heart of intersectionality between identity and oppression, but also challenges several aspects of intersectionality studies, especially as recent theorists increasingly turn away from identity politics in favor of a structural critique of power. These aspects of intersectionality include its often unsituated critique of power, as well as its reliance on a negatively defined consensus on anti‐oppression.
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Grasswick, Heidi. "Climate Change Science and Responsible Trust: A Situated Approach." Hypatia 29, no. 3 (2014): 541–57. http://dx.doi.org/10.1111/hypa.12090.
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I adopt a situated approach to the question of what would constitute responsible trust and/or distrust in climate change science, and I identify some of the major challenges for laypersons in their attempts to know well by placing their trust in climate change experts. I examine evidence that white males, as a group of relative privilege, are more likely to distrust the institutions of climate change science than are other demographic groups, and use this example to consider specific challenges facing those who occupy positions of privilege and who seek to place their epistemic trust wisely. I argue that the insights of feminist standpoint theory and epistemologies of ignorance concerning the role of positionality in knowledge production and the need for critical reflexivity can be applied to cases of epistemic trust as well; in some contexts, such as climate change science, considerations of how those differently situated from oneself place their trust will be valuable contributions to responsible assignments of trust.
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Angermann, Asaf. "The Diremption of Love: Gillian Rose on Agency, Mortality, and Hegelian Feminism." Hypatia 34, no. 2 (2019): 309–28. http://dx.doi.org/10.1111/hypa.12471.
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Gillian Rose (1947–1995) was an influential though idiosyncratic British philosopher whose work helped introduce the Frankfurt School's critical theory and renew interest in Hegel, Kierkegaard, and Jewish thought in Anglo‐American philosophy. After years of relative oblivion, her life and thought have recently received new attention in philosophy, sociology, and theology. However, her work's critical Hegelian contribution to feminist philosophy still remains unexplored. This article seeks to reassess the place and the meaning of feminism and gender identity in Rose's work by addressing both her philosophical writings and her personal memoir, written in the months preceding her untimely death. It argues that although Rose's overall work was not developed in a feminist context, her philosophy, and in particular her ethical‐political notion of diremption, is valuable for developing a critical feminist philosophy that overcomes the binaries of law and morality, inclusion and exclusion, power and powerlessness—and focuses on the meaning of love as negotiating, rather than mediating, these oppositions.
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Hancox‐Li, Leif. "Idealization and Abstraction in Models of Injustice." Hypatia 32, no. 2 (2017): 329–46. http://dx.doi.org/10.1111/hypa.12317.
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Charles Mills has argued against ideal theory in political philosophy on the basis that it contains idealizations. He calls for political philosophers to do more nonideal theory, namely political theory that pays more attention to the most visible oppressions in society, such as those based on race, gender, and class. Mills's argument relies on a distinction between idealization and abstraction. Idealizations involve adding false assumptions to one's model, which is unacceptable, whereas abstractions merely leave out details without undermining descriptive power. By studying formal models of injustice, I argue that the idealization/abstraction distinction is unhelpful. Either the distinction exists only relative to one's modeling purposes, or all models in political theory contain idealizations. Either way, the distinction does not help Mills's cause. Furthermore, there are arguments from philosophy of science for the epistemic benefits of idealizations. However, Mills's call for greater emphasis on the most visible mechanisms of oppression can be supported without relying on an idealization/abstraction distinction. I provide three alternative reasons for why we should prefer political theories that place more emphasis on race‐, class‐, and gender‐based oppression.
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Martinez, Jacqueline M. "Culture, Communication, and Latina Feminist Philosophy: Toward a Critical Phenomenology of Culture." Hypatia 29, no. 1 (2014): 221–36. http://dx.doi.org/10.1111/hypa.12061.
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An explication of the phenomenological sensibilities found in the work of Gloria Anzaldúa and other Latina feminist philosophers offers insight into the problem of bringing philosophy into greater relevance beyond academic and scholarly worlds. This greater relevance entails clear and direct contact with the immediacy of our communicative relationships with others, both inside and outside the academy, and allows for an interrogation of the totalizing perceptions that are at work within normative processes of epistemological legitimation. As a result of this interrogation, it is possible to cultivate perceptual capacities related to culture that intervene in the normatively tacit cultural dispositions that often limit the possibilities of understanding.
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DAVIS, ADRIAN L. V., and CHRISTIAN M. DESCHODT. "Two new species of Garreta Janssens, 1940 (Coleoptera: Scarabaeidae: Scarabaeinae) from Southern Africa." Zootaxa 4450, no. 2 (July 24, 2018): 242. http://dx.doi.org/10.11646/zootaxa.4450.2.4.
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Two new, putative, closely-related species of dung beetles are described in the genus Garreta Janssens, 1940 (tribe Gymnopleurini). Garreta australugens new species, is known from various dung types in the southeast lowlands of Africa (validated for South Africa, Mozambique and Zimbabwe with a probable record from Botswana). It is, here, separated at species level from its putative closest relative, Garreta lugens (Fairmaire, 1891), recorded from the lowlands of northeast Africa (validated for Kenya with additional records from Ethiopia, Somalia and Tanzania). These two taxa were formerly considered to comprise a single species. All specimens in the type series of Garreta namalugens new species, were recorded at low altitude in arid, rocky mountains from west central to northwest Namibia, mostly on dung in communal middens of the Rock Hyrax (Procavia capensis (Pallas, 1766)).
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Auclair, Joelle, and François Gagné. "Crowding Effects of Polystyrene Nanoparticles on Lactate Dehydrogenase Activity in Hydra Attenuata." Journal of Xenobiotics 10, no. 1 (September 16, 2020): 2–10. http://dx.doi.org/10.3390/jox10010002.
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Plastics pervade our environment and potentially release important quantities of plastic nanoparticles (NPs) from degradation in the environment. The purpose of this study was to examine the crowding effects of polystyrene NPs on lactate dehydrogenase (LDH) in vitro and following exposure to Hydra attenuata. First, LDH activity was measured in vitro in the presence of filamentous (F-)actin and NPs (50 and 100 nm diameter) to determine changes in viscosity and the fractal kinetics of LDH. The fractal dimension (fD) was also determined using the rescaled range analysis procedure. Secondly, these changes were examined in hydra exposed to NPs for 96h to concentrations of NPs. The data revealed that the addition of F-actin increased the rate of LDH at low substrate (pyruvate) concentrations compared to LDH alone with a gradual decrease in the rate with the addition of pyruvate, which is characteristic of the fractal behavior of enzymes in crowded environments. The addition of 50 and 100 nm NPs also produced these changes, which suggest that NPs could change the space properties of the LDH reaction. The fD was reduced to 0.85 and 0.91 with 50 and 100 nm NPs compared to 1.093 with LDH alone. Decrease in the fD was related with increased amplitudes and frequency in viscosity waves in the reaction media. Exposure of hydra to NPs confirmed the increase in LDH activity and the fD was significantly correlated with LDH activity (r = −0.5). Correction of LDH activity (residuals) still revealed an increase in LDH activity in hydra suggesting increased anaerobic metabolism by NPs. In conclusion, the presence of NPs in the intracellular space decreased the fD, which could influence LDH activity in organisms exposed to NPs.
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Foust, Mathew A. "The Feminist Pacifism of William James and Mary Whiton Calkins." Hypatia 29, no. 4 (2014): 889–905. http://dx.doi.org/10.1111/hypa.12115.
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In this paper, I accompany William James (1842–1910) and Mary Whiton Calkins (1863–1930) in the steps each takes toward his or her respective proposal of a moral equivalent of war. I demonstrate the influence of James upon Calkins, suggesting that the two share overlapping formulations of the problem and offer closely related—but significantly different—solutions. I suggest that Calkins's pacifistic proposal is an extension of that of her teacher—a feminist interpretation of his psychological and moral thought as brought to bear on the problem of war. Calkins's brand of pacifism widens the scope of James's “moral equivalent of war” in a way that is consonant with feminist ideals of inclusiveness and social justice. I conclude by commenting on how James's and Calkins's pacifism can continue to be extended fruitfully in contemporary feminist pacifist theory and practice.
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McGowan, Mary Kate, Ilana Walder‐Biesanz, Morvareed Rezaian, and Chloe Emerson. "On Silencing and Systematicity: The Challenge of the Drowning Case." Hypatia 31, no. 1 (2016): 74–90. http://dx.doi.org/10.1111/hypa.12224.
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Silencing is a speech‐related harm. We here focus on one particular account of silencing offered by Jennifer Hornsby and Rae Langton. According to this account, silencing is systematically generated, illocutionary‐communicative failure (of a very specific sort). We here raise an apparent challenge to that account. In particular, we offer an example—the drowning case—that meets these conditions of silencing but does not intuitively seem to be an instance of it. First, we explore several conditions one might add to the Hornsby‐Langton account, but we argue that none are satisfactory. Then, we further explore the systematicity condition, which is insufficiently characterized in the current literature. Although we explore several promising ways to further characterize this condition, we ultimately conclude that more work needs to be done. Consequently, because this systematicity condition is under‐specified, the Hornsby‐Langton account of silencing is incomplete.
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Hilker, M., T. Richtler, C. E. Barbosa, M. Arnaboldi, L. Coccato, and C. Mendes de Oliveira. "The Hydra I cluster core." Astronomy & Astrophysics 619 (November 2018): A70. http://dx.doi.org/10.1051/0004-6361/201731737.
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Context. NGC 3311, the central galaxy of the Hydra I cluster, shows signatures of recent infall of satellite galaxies from the cluster environment. Previous work has shown that the line-of-sight velocity dispersion of the stars and globular clusters in the extended halo of NGC 3311 rises up to the value of the cluster velocity dispersion. In the context of Jeans models, a massive dark halo with a large core is needed to explain this finding. However, position dependent long-slit measurements show that the kinematics are still not understood. Aims. We aim to find kinematic signatures of sub-structures in the extended halo of NGC 3311. Methods. We performed multi-object spectroscopic observations of the diffuse stellar halo of NGC 3311 using VLT/FORS2 in MXU mode to mimic a coarse “IFU”. The slits of the outermost masks reach out to about 35 kpc of galactocentric distance. We use PPXF to extract the kinematic information of velocities, velocity dispersions and the high-order moments h3 and h4. Results. We find a homogeneous velocity field and velocity dispersion field within a radius of about 10 kpc. Beyond this radius, both the velocities and the velocity dispersion start to depend on azimuth angle and show a significant intrinsic scatter. The inner spheroid of NGC 3311 can be described as a slow rotator. Outside 10 kpc the cumulative angular momentum is rising, however, without showing an ordered rotation signal. If the radial dependence alone is considered, the velocity dispersion does not simply rise but fills an increasingly large range of dispersion values with two well defined envelopes. The lower envelope is about constant at 200 km s−1. The upper envelope rises smoothly, joining the velocity dispersion of the outer globular clusters and the cluster galaxies. We interpret this behaviour as the superposition of tracer populations with increasingly shallower radial distributions between the extremes of the inner stellar populations and the cluster galaxies. Simple Jeans models illustrate that a range of mass profiles can account for all observed velocity dispersions, including radial MOND models. Conclusions. The rising velocity dispersion of NGC 3311 apparently is a result of averaging over a range of velocity dispersions related to different tracer populations in the sense of different density profiles and anisotropies. Jeans models using one tracer population with a unique density profile are not able to explain the large range of the observed kinematics. Previous claims about the cored dark halo of NGC 3311 are therefore probably not valid. This may in general apply to central cluster galaxies with rising velocity dispersion profiles, where infall processes are important.
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Augustin, René, André Franke, Konstantin Khalturin, Rainer Kiko, Stefan Siebert, Georg Hemmrich, and Thomas C. G. Bosch. "Dickkopf related genes are components of the positional value gradient in Hydra." Developmental Biology 296, no. 1 (August 2006): 62–70. http://dx.doi.org/10.1016/j.ydbio.2006.04.003.
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Cutas, Daniela, and Anna Smajdor. "Postmenopausal Motherhood Reloaded: Advanced Age and In Vitro Derived Gametes." Hypatia 30, no. 2 (2015): 386–402. http://dx.doi.org/10.1111/hypa.12151.
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In this paper we look at the implications of an emerging technology for the case in favor of, or against, postmenopausal motherhood. Technologies such as in vitro derived gametes (sperm and eggs derived from nonreproductive cells) have the potential to influence the ways in which reproductive medicine is practiced, and are already bringing new dimensions to debates in this area. We explain what in vitro derived gametes are and how their development may impact on the case of postmenopausal motherhood. We briefly review some of the concerns that postmenopausal motherhood has raised—and the implications that the successful development, and use in reproduction, of artificial gametes might have for such concerns. The concerns addressed include arguments from nature, risks and efficacy, reduced energy of the mother, and maternal life expectancy. We also consider whether the use of in vitro derived gametes to facilitate postmenopausal motherhood would contribute to reinforcing a narrow, geneticized account of reproduction and a pro‐reproductive culture that encourages women to produce genetically related offspring at all costs.
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Toole, Briana. "From Standpoint Epistemology to Epistemic Oppression." Hypatia 34, no. 4 (2019): 598–618. http://dx.doi.org/10.1111/hypa.12496.
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Standpoint epistemology is committed to a cluster of views that pays special attention to the role of social identity in knowledge‐acquisition. Of particular interest here is the situated knowledge thesis. This thesis holds that for certain propositions p, whether an epistemic agent is in a position to know that p depends on some nonepistemic facts related to the epistemic agent's social identity. In this article, I examine two possible ways to interpret this thesis. My first goal here is to clarify existing interpretations of this thesis that appear in the literature but that are undeveloped and often mistakenly conflated. In so doing, I aim to make clear the different versions of standpoint epistemology that one might accept and defend.This project is of significance, I argue, because standpoint epistemology provides helpful tools for understanding a phenomenon of recent interest: epistemic oppression. My second goal is to provide an analysis that makes clear how each of the readings I put forth can be used to illuminate forms of epistemic oppression.