Academic literature on the topic 'Percentage of DNA in the tail'
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Journal articles on the topic "Percentage of DNA in the tail"
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Fraser, L., Ł. Zasiadczyk, and C. S. Pareek. "Effects of boar variability on comet-detected sperm-DNA damage following cryopreservation." Animal Production Science 58, no. 2 (2018): 252. http://dx.doi.org/10.1071/an16274.
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Assessment of sperm-DNA integrity is a crucial issue in male fertility. In the present study, parameters derived from the image analysis of comets after single-cell gel electrophoresis were used to analyse the types of DNA damage of frozen–thawed boar spermatozoa. Semen, frozen in a cryoprotectant-free extender or in cryoprotectant-based extenders, was analysed for DNA fragmentation and with the following comet tail measures: percentage DNA in comet tail, comet tail length and olive tail moment. The percentages of sperm DNA damage in the comet tails were classified as Type 0 (no DNA damage), Type I (very low DNA damage), Type II (light DNA damage), Type III (medium DNA damage) and Type IV (heavy DNA damage). Sperm motility characteristics and membrane integrity were assessed in the pre-freeze and frozen–thawed semen samples. Assessment of sperm DNA fragmentation and comet tail measures showed marked inter-boar variability following cryopreservation. However, consistent differences among the boars, with respect to cryo-induced sperm DNA damage, were detected by the comet tail length and olive tail moment. Besides Type IV, all types of DNA damage were detected in the cryoprotectant-based extenders. It was found that the frequency of Type II and Type III of DNA damage of frozen–thawed spermatozoa was significantly greater in the cryoprotectant-based and cryoprotectant-free extenders respectively. Deterioration in the quality of the sperm DNA integrity was concomitant with a marked decline in sperm motility characteristics, reduced plasma membrane integrity and higher lipid peroxidation and aspartate aminotransferase activity after cryopreservation. It can be suggested that the comet-assay parameters, coupled with routine laboratory tests, are useful to improve the sperm evaluations of post-thaw quality of semen from individual boars and would offer more comprehensive information for a better understanding of the degree of cryo-induced sperm-DNA damage.
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Mohsin Bhat, Towseef, M. Y. K. Ansari, Sana Choudhary, Rumana Aslam, and Alka. "Synergistic Cytotoxic Stress and DNA Damage in Clover (Trifolium repens) Exposed to Heavy Metal Soil from Automobile Refining Shops in Kashmir-Himalaya." ISRN Toxicology 2011 (January 5, 2011): 1–7. http://dx.doi.org/10.5402/2011/109092.
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Coexposure to heavy metals occurs in many occupational settings, such as automobile refining shops, pigment, and batteries production. Heavy metals around automobile refining shops were tested for their ability to induce synergistic cytogenetic effects in Trifolium repens L. by using the chromosomal aberrasions (CAs), micronucleus (MN) and comet assay. A significant increase in micronucleus (MN), chromosomal abrations (CAs), percentage of nuclei with comet tails (NCTs), the relative comet tail length (CTL), comet tail DNA (CT, DNA), and tail moment (TM) were observed with increased concentration of three heavy metals, like Cd, Pb, Hg. The present result indicate that exposure of T. repens to soils contaminated by heavy metals around automobile refining shops shows clastogenicity, cytotoxicity, and DNA damage at higher concentrations.
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Han, Jun Song, Xin Lu Lv, Ya Li Gao, Xiang Gao, and De Qi Xiong. "Analysis of DNA Damages of Gonadal Cells of Hemicentrotus pulcherrimus in Petroleum Hydrocarbons." Applied Mechanics and Materials 522-524 (February 2014): 251–56. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.251.
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The single cell gel electrophoresis (SCGE) is a rapid and sensitive procedure for measuring strand breaks in DNA. In the present study, sea urchin (Hemicentrotus pulcherrimus) was chosen as the test organism and SCGE was applied to assess DNA damage of its gonadal cells exposed to petroleum hydrocarbon. The gonadal cells of sea urchin had been seriously damaged above 50 mg/L of Water Accommodated Fractions (WAFs), whileas no damages occurred in the lower concentrations. There were good linear relationships between exposure days and DNA damage rate, percentage of DNA in the comet tail (%TDNA) as well as comet tail length (TL).
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Ahbab, M. A., Ü. Ündeğer, N. Barlas, and N. Başaran. "In utero exposure to dicyclohexyl and di-n-hexyl phthalate possess genotoxic effects on testicular cells of male rats after birth in the comet and TUNEL assays." Human & Experimental Toxicology 33, no. 3 (July 8, 2013): 230–39. http://dx.doi.org/10.1177/0960327113494903.
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Phthalates are diester derivatives of phthalic acid widely used in many commercial applications. The aim of this study is therefore to evaluate possible genotoxicity of di- n-hexyl phthalate (DHP) and dicyclohexyl phthalate (DCHP) at different concentrations using single-cell gel electrophoresis (comet) and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end-labeling (TUNEL) assays in testes samples of male rat pups. DCHP and DHP in corn oil were administered to the pregnant rats by gavage at the doses of 0 (vehicle), 20, 100, and 500 mg kg−1 day−1 from gestational day 6 (GD6) to GD19. After delivery, male rats were allowed to grow until prepubertal, pubertal, and adulthood. At necropsy, the blood samples were collected from heart and were excised immediately. The apoptotic cells of prepubertal, pubertal, and adult testis were detected using TUNEL assay. The comet assay was performed on blood lymphocytes and testes samples of adult male rats. The comet assay results showed that tail length, tail intensity, olive tail moment (OTM), and percentage of DNA present in tail were higher when DHP content was increased. Judging from the values of OTM and percentage of DNA, DHP could significantly induce DNA breakage at doses of 100 and 500 mg kg−1 day−1 compared with the control group. An increase in TUNEL-positive cells of prepubertal, pubertal, and adult testicular cells was observed in the treated groups. In conclusion, prenatal exposure to DHP and DCHP may possess genotoxic risk to testicular cells of rats at all stages of development, even at adulthood.
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Wendisch, M., G. Wunderlich, R. Freudenberg, J. Kotzerke, and R. Runge. "DNA damage in lymphocytes after irradiation with 211At and 188Re." Nuklearmedizin 48, no. 06 (2009): 221–26. http://dx.doi.org/10.3413/nukmed-0262.
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Summary Aim: Ionising radiation produces many types of DNA lesions of different complexity. High linear energy transfer (LET) types of radiation are biological more effective than low LET radiation. In the present work we applied the single cell gel electrophoreses (comet assay) to study the induction of initial DNA damage, efficiency of repair and residual DNA damage in lymphocytes after treatment with 211At and 188Re. Methods: Peripheral blood mononuclear cells (PBMC) were isolated from heparinized blood of healthy donors and irradiated with 211At and 188Re at different doses. The comet assay was performed under alkaline and neutral conditions in order to detect the initial DNA damage and its repair. The measure of damage was % tail DNA (percentage of DNA in the tail). Results: After treatment of cells with 188Re the initial DNA damage (% tail DNA) detected with the alkaline comet assay was higher than the damage measured for 211At. The neutral comet assay estimated higher tail intensities for 211At in contrast to 188Re. Compared with the complete repair (10%) after irradiation with 188Re, the radiotoxicity of alpha particles indicated reduced rejoining of DNA strand breaks (60–80% residual damage). Rejoining of DNA damage measured by the neutral comet method detected about 70% unrepaired strand breaks for 211At and 188Re. Conclusions: There are major differences between the repair of strand breaks caused by 188Re and 211At detected by the alkaline comet assay. The DNA-damage induced by the high LET Emitter 211At remains nearly unrepaired detected by both alkaline and neutral comet assay. Represented data following irradiation of lymphocytes with alpha and beta particles demonstrated higher biological effectiveness of 211At by factors of 2.0–2.5.
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Ambreen, Faiza, and Muhammad Javed. "Nuclear Damage in Peripheral Erythrocytes of Cyprinus Carpio Exposed to Binary Mixture of Pesticides." Journal of Zoo Biology 2, no. 1 (December 22, 2019): 39–47. http://dx.doi.org/10.33687/zoobiol.002.01.1506.
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The present study was undertaken to examine the DNA damage in peripheral blood erythrocytes of Cyprinus carpio under the binary exposure of bifenthrin and chlorpyrifos by using single cell gel electrophoresis (SCGE). Limited efforts have been made to study the genotoxic effect for long duration period. Therefore, the present investigation was aimed to assess the genotoxicity of pesticide mixture to the freshwater carp, Cyprinus carpio at sub-lethal concentration exposure (33% LC50). At first 96-hr LC50 value of pesticide, the mixture was determined for Cyprinus carpio in a static system and then sub-lethal concentration was calculated and fish was exposed to this sub-lethal concentration of the mixture in glass aquaria for 70 days (five fortnights) at constant laboratory conditions. Peripheral blood erythrocytes were taken on a fortnightly basis for the time-dependent DNA damage assessment in-terms of percentage of damaged cells, genetic damage index and a cumulative tail length of comets. Concentration-dependent increase in the percentage of DNA damaged cells were observed up to a 4th fortnight, followed by a slight decrease in the 5th fortnight. Similarly, statistically significant time-dependent DNA damage was observed in terms of percentage of damaged cells, genetic damage index and a cumulative tail length of comets in treated fish (at 33% of LC50) as compared to control groups. The results supported the use of SCGE for evaluating the toxicity of pollutants which may be used as part of environmental monitoring programs.
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Jaenisch, Rodrigo B., Giuseppe P. Stefani, Camila Durante, Chalyne Chechi, Vítor S. Hentschke, Douglas D. Rossato, Anelise Sonza, Cláudia R. Rhoden, and Pedro Dal Lago. "Respiratory muscle training decreases diaphragm DNA damage in rats with heart failure." Canadian Journal of Physiology and Pharmacology 96, no. 3 (March 2018): 221–26. http://dx.doi.org/10.1139/cjpp-2017-0069.
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Respiratory muscle training (RMT) promotes beneficial effects on respiratory mechanics, heart and lung morphological changes, and hemodynamic variables in rats with heart failure (HF). However, the relation between RMT effects and diaphragm oxidative stress remains unclear. Therefore, the aim of this study was to evaluate the RMT effects on diaphragm DNA damage in HF rats. Wistar rats were allocated into 4 groups: sedentary sham (Sed-Sham, n = 8), trained sham (RMT-Sham, n = 8), sedentary HF (Sed-HF, n = 8), and trained HF (RMT-HF, n = 8). The animals underwent a RMT protocol (30 min/day, 5 days/week for 6 weeks), whereas sedentary animals did not exercise. Groups were compared by a two-way ANOVA and Tukey’s post hoc tests. In rats with HF, RMT promoted reduction in pulmonary congestion (p < 0.0001) and left ventricular end diastolic pressure (p < 0.0001). Moreover, RMT produced a decrease in the diaphragm DNA damage in HF rats. This was demonstrated through the reduction in the percentage of tail DNA (p < 0.0001), tail moment (p < 0.01), and Olive tail moment (p < 0.001). These findings showed that a 6-week RMT protocol in rats with HF promoted an improvement in hemodynamic function and reduces diaphragm DNA damage.
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Joshi, Mayur S., Yogendra Verma, Anil K. Gautam, Vijay K. Shivgotra, Girish Parmar, and Sunil Kumar. "Assessment of Genetic Damage Among Chewers of Mixture Containing Mainly Areca Nut and Tobacco." Asia Pacific Journal of Public Health 23, no. 6 (September 13, 2011): 852–60. http://dx.doi.org/10.1177/1010539511419838.
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Chewing mixture containing areca nut and tobacco is believed to be associated with oral cancer. Habit of chewing such mixture is prevalent among South Asian countries. This study aimed to evaluate the genotoxic effect of areca nut and tobacco on human lymphocytes. Peripheral blood from 107 subjects (nonchewers, 48; chewers, 59, including 20 subjects with oral submucous fibrosis [OSMF]) analyzed by cytokinesis-block micronucleus (CBMN) and alkaline comet assay. Nuclear anomalies, namely, binucleated cells with micronuclei (BN MN), total MN, nucleoplasmic bridge, and nuclear buds were higher in chewers whereas elevation in BN MN and total MN were significant among subjects with OSMF than nonchewers. DNA damage assessed by comet assay showed increased percentage of Tail DNA, Tail moment, and Olive tail moment among chewers as well as OSMF subjects. Significant positive correlation was observed between induction of CBMN and consumption of quids per day ( r = .280, P = .033). Results suggested cytotoxic and genotoxic potential of mixture containing areca nut and tobacco.
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Buchynska, L. G., O. V. Brieieva, N. P. Iurchenko, V. V. Protsenko, and S. V. Nespryadko. "DNA DAMAGE IN TUMOR CELLS AND PERIPHERAL BLOOD LYMPHOCYTES OF ENDOMETRIAL CANCER PATIENTS ASSESSED BY THE COMET ASSAY." Experimental Oncology 39, no. 4 (December 22, 2017): 299–303. http://dx.doi.org/10.31768/2312-8852.2017.39(4):299-303.
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To date, genome instability is considered to be a common feature not only of tumor cells, but also of non-malignant cells of cancer patients, including peripheral blood lymphocytes (PBLs). The issue of the association between genome instability in tumor cells and PBLs, as well as of its relationship with tumor progression remains poorly understood. Aim: To evaluate the level DNA damage in tumor cells and PBLs of endometrial cancer (EC) patients with regard to clinical and morphological characteristics of the patients. Materials and Methods: DNA damage was assessed in 106 PBLs samples and 42 samples of tumor cell suspension from EC patients by comet assay. PBLs from 30 healthy women were used as control. The level of DNA damage was expressed as the percentage of DNA in the comet tails (% tail DNA). Results: It was revealed that the amount of DNA damage in PBLs of EC patients was 2.2 times higher in comparison with that of healthy donors (8.3 ± 0.7 and 3.7 ± 0.4% tail DNA, respectively) (p < 0.05). In this study, no association between the levels of DNA damage in endometrial tumor cells and PBLs was observed (r = 0.11; p > 0.05). The amounts of DNA damage both in tumor cells and PBLs were not related to the degree of tumor differentiation as well as the depth of myometrial invasion, but depended on the body mass index (BMI) of EC patients: high level of lesions was observed in patients with elevated BMI values. Furthermore, the level of DNA damage in tumor cells was associated to familial aggregation of cancer and was significantly higher in endometrial cells from patients with family history of cancer vs that from EC patients with sporadic tumors (32.3 ± 2.9 and 22.8 ± 1.8% tail DNA, respectively) (p < 0.05). It was also found that for women who had high level of DNA damage in PBLs, the risk of EC was greater (odds ratio value of 3.5) compared to those with low level of such lesions. Conclusion: Genome instability that appears as an increased level of DNA damage in tumor cells and PBLs of EC patients is associated with BMI and family history of cancer and can reflect a predisposition to cancer.
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Chen, Yan, Xiaodong Liu, Christopher H. K. Cheng, Tony Gin, Kate Leslie, Paul Myles, and Matthew T. V. Chan. "Leukocyte DNA Damage and Wound Infection after Nitrous Oxide Administration." Anesthesiology 118, no. 6 (June 1, 2013): 1322–31. http://dx.doi.org/10.1097/aln.0b013e31829107b8.
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Abstract Background: Nitrous oxide inactivates methionine synthase and may lead to DNA damage and wound infection. By using single-cell gel electrophoresis (comet assay), the authors determined the effect of nitrous oxide on DNA damage in circulating leukocytes. Methods: In this double-blind, randomized controlled trial, 91 patients undergoing major colorectal surgery were randomized to receive 70% nitrous oxide (n = 31) or nitrous oxide-free anesthesia using 30 (n = 30) or 80% (n = 30) oxygen. Venous blood was collected before and 24 h after surgery. The primary outcome was extent of DNA damage, quantified as the percentage of DNA staining intensity in the comet tail using digital fluorescence microscopy. Incidence of postoperative wound infection was also recorded. Results: Nitrous oxide exposure was associated with a two-fold increase in the percentage of DNA intensity in tail (P = 0.0003), but not in the 30 (P = 0.181) or 80% oxygen groups (P = 0.419). There was a positive correlation between the duration of nitrous oxide exposure and extent of DNA damage, r = 0.33, P = 0.029. However, no correlation was observed in nitrous oxide-free patients. The proportions of postoperative wound infection, using the Centers for Disease Control and Prevention criteria, were 19.4% (6 of 31) in the 70% nitrous oxide group and 6.7% (2 of 30) in both the 30 and 80% oxygen groups, P = 0.21. An increase in DNA damage was associated with a higher risk of wound infection, adjusted odds ratio (95% CIs): 1.19 (1.07–1.34), P = 0.003. Conclusions: Nitrous oxide increased DNA damage compared with nitrous oxide-free anesthesia and was associated with postoperative wound infection.
Dissertations / Theses on the topic "Percentage of DNA in the tail"
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Wong, Alvaro Yat Set. "´´Evaluación de la compatibilidad de tinciones no fluorescentes de Diffquik, Giemsa, Fastblast y de Feulgen con el Bioensayo Cometa en el ADN espermático humano´´." Bachelor's thesis, Universidad Ricardo Palma, 2016. http://cybertesis.urp.edu.pe/handle/urp/826.
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La fertilidad masculina puede ser medida mediante un espermatograma convencional, sin embargo este examen no incluye la valoración de la integridad del ADN espermático. Esta variable ha sido correlacionada con las tasas de fertilización, viabilidad y desarrollo del embrión, convirtiéndose en una herramienta de importancia clínica tanto para los programas de reproducción animal como los tratamientos de fertilidad asistida.
El bioensayo Cometa es capaz de determinar de una manera exacta el valor de la integridad del ADN espermático, lamentablemente este examen no es de uso rutinario por su elevado costo de implementación ya que utiliza microscopia especializada y tinciones fluorescentes para evidenciar la migración del ADN.
El objetivo de esta investigación fue evaluar la compatibilidad de las tinciones no fluorescentes Diffquik, Giemsa, de Feulgen y FastBlast en el bioensayo Cometa usando un método visual y automatizado. Se utilizaron 15 eyaculados previamente seleccionados de acuerdo al manual OMS 2010, para luego ser capacitados en búsqueda de homogeneidad adecuada para la experimentación. Cada muestra fue expuesta a una gradiente de Peróxido de hidrogeno (0, 10, 30,60 y 100 mM) por 1 hora a 4°C para luego evaluar el coeficiente de daño mediante el método visual y porcentaje de ADN en la cola mediante el método automatizado.
Las pendientes de la regresión lineal en el método visual indican que los valores obtenidos por la tinción control SybrGreen (m=3,69) difieren con Giemsa (m=3,45) y Diffquik (m=2,57). En el método automatizado de igual manera SybrGreen (m=0.83), Giemsa (m=0,79) y Diffquik (m=0,77).
Sin embargo SybrGreen es 1,06 veces más efectivo que Giemsa en el visual y 1,05 veces en el automatizado, sugiriendo una compatibilidad con el bioensayo cometa. De igual manera SybrGreen es 1,07 veces más efectivo que Diffquik en el visual y 1,44 veces en el automatizado, concluyendo una compatibilidad solo en el método visual.Male fertility can be measured by a conventional semen analysis, however, this examination does not include the assessment of sperm DNA integrity. This variable has been correlated with fertilization rates, embryo viability and development, becoming a tool of clinical importance for both animal breeding programs and assisted fertility treatments.
Comet bioassay is able to determine an exact way the value of sperm DNA integrity, unfortunately this test is not routinely used because of its high cost of implementation because it uses specialized microscopy and fluorescent dyes to demonstrate DNA migration.
The objective of this research was to evaluate the compatibility of non-fluorescent dyes Diffquik, Giemsa, Feulgen and Comet FastBlast in the bioassay using a visual and automated method. 15 ejaculates were used previously manually selected according to WHO 2010 and then be trained in finding adequate homogeneity for experimentation. Each sample was exposed to a hydrogen peroxide gradient (0, 10, 30,60 and 100 mM) for 1 hour at 4 ° C and then assess the damage coefficient by visual method and percentage of DNA in the tail by automated method.
The slopes of the linear regressions on the visual method indicate that the values obtained by the SybrGreen Control staining (m = 3.69) differ with Giemsa (m = 3.45) and Diffquik (m = 2.57). In the same way automated method SybrGreen (m = 0.83), Giemsa (m = 0.79) and Diffquik (m = 0.77).
However SybrGreen is 1.06 times more effective than Giemsa visual and 1.05 times in the automated, suggesting a comet support bioassay. Similarly SybrGreen is 1.07 times more effective than Diffquik visual and 1.44 times in the automated, concluding compatibility only in the visual method.
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Washington, Ashley. "Functional tests of [beta] tubulins in Drosophila sperm tail morphology." Dayton, Ohio : University of Dayton, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1229709260.
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Harvey, A. C. "Characterisation of the histone H2A C-terminal tail in DNA damage responses in S. cerevisiae." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603822.
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Within the eukaryotic nucleus DNA is compacted into chromatin, the smallest unit of which is the nucleosome. Nuclear processes that require direct access to DNA such as transcription, replication and repair must therefore operate in a chromatin context/ It is recently become apparent that proteins that contribute to chromatin structure and its modulation are of integral importance in these essential pathways. Many studies have shown the importance of covalent modifications of histone proteins in regulating chromatin structure and in protein recruitment. Such modifications can include phosphorylation, acetylation, methylation and ubiquitination. It has previously been demonstrated that the phosphorylation of serine 129 (S129) in the C-terminal tail of budding yeast histone H2A is important for DNA double-strand break responses. Here, we take a systematic site-directed mutagenesis approach to determine the importance of other modifiable residues in the H2A C-terminal tail. We identify another histone H2A serine residue (S122) that is also important for cell survival in the presence of DNA damaging agents. We have characterized yeast strains lacking this residue and find that this residue does not significantly affect the ability of cells to detect or signal the presence of DNA damage. In contrast, these strains are growth deficient, sporulation defective and impaired in DNA double-strand break repair. Moreover, we shown that H2A S122 and H2A S129 are functioning distinctly in DNA damage responses. We also further characterize the role of H2A S129 phosphorylation in DNA damage and cellular stress responses. Finally, it has previously been shown that the yeast linker histone plays a role in mediating DNA DSB repair, and the relationship with the H2A C-terminal tail was examined.
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HUBÁLEK, Martin. "Možnosti fixace vzorků pro měření obsahu DNA u ryb průtokovou cytometrií." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-375884.
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This thesis aims to assess the possibility of the usage of various biological fixatives for fish cell and tissues samples in order to extend its storage for later flow cytometric measurement of DNA content. The model species chosen were sterlet and tench, from which three types of samples were obtained: blood and fin tissue of subadult / adult individuals and tail tissue of hatched larvae. Altogether 13 fixation methods were tested for each type of sample of both model species. Methods were chosen based upon their easy feasibility and low time-consumption. The samples were measured on flow cytometer in native state immediately after sampling and placing in physiological saline and after 1, 5 and 10 days of fixation during which they were stored in a fridge or in a freezer at -80 ?C. Their analysis was carried out simultaneously with standards native cells from tench fin tissue when investigating sterlet samples, and commercially available fixed trout erythrocytes for tench samples. A fluorochrome used was 4',6-diamidine-2'-phenylindole dihydrochloride (DAPI; with excitation/emission maxima 358 / 461 nm). Based on the evaluation of coefficients of variation (CV) of fixed samples and the changes in their fluorescence levels in comparison with native state, optimal procedures for extended storage of all types of samples from both model species are suggested.
Books on the topic "Percentage of DNA in the tail"
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Kirchman, David L. The ecology of viruses. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0010.
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In addition to grazing, another form of top-down control of microbes is lysis by viruses. Every organism in the biosphere is probably infected by at least one virus, but the most common viruses are thought to be those that infect bacteria. Viruses come in many varieties, but the simplest is a form of nucleic acid wrapped in a protein coat. The form of nucleic acid can be virtually any type of RNA or DNA, single or double stranded. Few viruses in nature can be identified by traditional methods because their hosts cannot be grown in the laboratory. Direct count methods have found that viruses are very abundant, being about ten-fold more abundant than bacteria, but the ratio of viruses to bacteria varies greatly. Viruses are thought to account for about 50% of bacterial mortality but the percentage varies from zero to 100%, depending on the environment and time. In addition to viruses of bacteria and cyanobacteria, microbial ecologists have examined viruses of algae and the possibility that viral lysis ends phytoplankton blooms. Viruses infecting fungi do not appear to lyse their host and are transmitted from one fungus to another without being released into the external environment. While viral lysis and grazing are both top-down controls on microbial growth, they differ in several crucial respects. Unlike grazers, which often completely oxidize prey organic material to carbon dioxide and inorganic nutrients, viral lysis releases the organic material from hosts more or less without modification. Perhaps even more important, viruses may facilitate the exchange of genetic material from one host to another. Metagenomic approaches have been used to explore viral diversity and the dynamics of virus communities in natural environments.
Book chapters on the topic "Percentage of DNA in the tail"
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Hendrix, R. W. "Tail Length Determination in Double-Stranded DNA Bacteriophages." In Current Topics in Microbiology and Immunology, 21–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73115-0_2.
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Casjens, Sherwood R., and Ian J. Molineux. "Short Noncontractile Tail Machines: Adsorption and DNA Delivery by Podoviruses." In Viral Molecular Machines, 143–79. Boston, MA: Springer US, 2011. http://dx.doi.org/10.1007/978-1-4614-0980-9_7.
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Didenko, Vladimir V. "Zebra Tail Amplification: Accelerated Detection of Apoptotic Blunt-Ended DNA Breaks by In Situ Ligation." In Fast Detection of DNA Damage, 167–77. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7187-9_15.
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Choi, Jaehyuk, Junhyun Jeon, and Yong-Hwan Lee. "Identification of T-DNA Integration Sites: TAIL-PCR and Sequence Analysis." In Fungal Biology, 217–22. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-10503-1_19.
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Fujimoto, Satoru, Sachihiro Matsunaga, and Minoru Murata. "Mapping of T-DNA and Ac/Ds by TAIL-PCR to Analyze Chromosomal Rearrangements." In Methods in Molecular Biology, 207–16. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-4931-1_17.
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Zheng, Chunyang, and Jeffrey J. Hayes. "Probing Core Histone Tail–DNA Interactions in a Model Dinucleosome System." In Chromatin and Chromatin Remodeling Enzymes, Part A, 179–93. Elsevier, 2003. http://dx.doi.org/10.1016/s0076-6879(03)75012-5.
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Murugiah, P. "Activity Index and Lotkas's Law Validation on Human DNA Research." In Advances in Library and Information Science, 39–47. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1309-5.ch005.
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The chapter analyzes the activity index and Lotka's law validation on human DNA research during 1989-2013. This present study uses Scopus database to find publications of ‘Human DNA'. The study showed that the lowest relative growth rate (RGR) was 0.04 in 2008, 2010, 2012, and 2014. Similarly, the RGR rose to 0.75 in 1990, and the average mean value of RGR was 0.15. The total no. of authors was (an) = 82886 for 42 publications that each author contributed in the human DNA research. The authors reported that the percentage that authors predicted by Lotka's authors (F-P)2/P = 1526.66.
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Kašuba, Vilena, Vedran Micek, Alica Pizent, Blanka Tariba Lovaković, Davor Želježić, Nevenka Kopjar, and Mirta Milić. "DNA Damage and Glutathione Peroxidase Activity in Liver and Kidney Cells in Wistar Rats Exposed to Terbuthylazine (TERB) for 28 Consecutive Days." In Rodents [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94178.
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The potential of low doses of the chloro-triazine herbicide terbuthylazine to induce DNA damage and impair activity of glutathione peroxidase (GPx) was evaluated in kidney and parenchymal and non-parenchymal liver cells of adult male rats. In a 28-day study, terbuthylazine was applied daily by oral gavage at doses: 0.004, 0.4 and 2.29 mg/kg bw/day. Tail Intensity (T Int) and Tail Length (TL) were used as descriptors of DNA damage. In the kidney, Tail Int was significantly different in all treated groups, while TL was different in 0.4 and 2.29 mg/kg bw/day groups, compared to controls. Significant differences in TL were recorded in parenchymal and non-parenchymal liver cells of all treated groups. Tail Int was significantly different from controls in non-parenchymal liver cells at all applied doses and in parenchymal cells at terbuthylazine doses of 0.004 and 2.29 mg/kg bw/day. A significant increase in GPx activity was observed only in the kidney at doses 0.4 and 2.29 mg/kg bw/day compared to the controls indicating its possible role in the protection of kidney from free radicals. It appears that repeated exposure to low doses of terbuthylazine could cause DNA instability in kidney cells and in parenchymal and non-parenchymal liver cells in rats.
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Minati, Gianfranco. "The Dynamic Usage of Models (DYSAM) as a Theoretically-Based Phenomenological Tool for Managing Complexity and as a Research Framework." In Cybernetics and Systems Theory in Management, 176–90. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-61520-668-1.ch010.
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In this paper, after recalling some fundamental concepts used in the science of complexity, we focus on theoretical and applicative cases of interest for the science of management of complex systems, where processes of emergence occur with the acquisition of new properties. The tool proposed is the DYnamical uSAge of Models (DYSAM). Within this framework we then focus upon a) the theoretical difference between growth and development; b) the sustainability of development rather than of growth as originally introduced in the literature; c) the concept of long tail (when, after initial large volume sales, low-revenue and infrequent buying may become a very important percentage of the entire business) as in telecommunications and management of long-tailed systems; d) non-reductionist management of complexity not reduced to solutions, and e) a future line of research to model processes of emergence.
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Prabu, S. Lakshmana. "Drug Discovery." In Advances in Medical Technologies and Clinical Practice, 1–46. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7326-5.ch001.
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Modern chemistry foundations were made in between the 18th and 19th centuries and have been extended in 20th century. R&D towards synthetic chemistry was introduced during the 1960s. Development of new molecular drugs from the herbal plants to synthetic chemistry is the fundamental scientific improvement. About 10-14 years are needed to develop a new molecule with an average cost of more than $800 million. Pharmaceutical industries spend the highest percentage of revenues, but the achievement of desired molecular entities into the market is not increasing proportionately. As a result, an approximate of 0.01% of new molecular entities are approved by the FDA. The highest failure rate is due to inadequate efficacy exhibited in Phase II of the drug discovery and development stage. Innovative technologies such as combinatorial chemistry, DNA sequencing, high-throughput screening, bioinformatics, computational drug design, and computer modeling are now utilized in the drug discovery. These technologies can accelerate the success rates in introducing new molecular entities into the market.
Conference papers on the topic "Percentage of DNA in the tail"
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Pivoňková, Hana, Kateřina Němcová, Petra Horáková, Luděk Havran, Hana Macíčková-Cahová, Michal Hocek, and Miroslav Fojta. "Tail labelled oligonucleotide probes for the detection of DNA-protein interactions." In XVth Symposium on Chemistry of Nucleic Acid Components. Prague: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 2011. http://dx.doi.org/10.1135/css201112435.
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Fujimori, R., Y. Komatsu, M. Fukuda, T. Miyakawa, R. Morikawa, and M. Takasu. "Analysis of the histone protein tail and DNA in nucleosome using molecular dynamics simulation." In 4TH INTERNATIONAL SYMPOSIUM ON SLOW DYNAMICS IN COMPLEX SYSTEMS: Keep Going Tohoku. American Institute of Physics, 2013. http://dx.doi.org/10.1063/1.4794641.
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Dalby Kristensen, S., K. M. Roberts, and J. F. Martin. "INCREASE IN MEGAKARYOCYTE SIZE AND PLOIUY PRECEDES ACCELERATION OF ATHEROGENESIS IN THE HYPERCHOLESTEROLAEMIC RABBIT." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643412.
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Platelet derived growth factor(s) probably synthesized by the megakaryocyte are important in atherogenesis. In a pilot study destruction of the circulating platelets was induced by injection of goat serum containing a specific platelet antibody (APS) to rabbits fed a high cholesterol diet (2g per day) for 12 weeks. Seven days after APS the percentage of atheroma in the aorta measured by planimetry was increased in these animals compared to control animals on the same diet that had been injected with goat serum (GS) 7 days before. In a new study 15 pairs of male litter mate rabbits on high cholesterol diet were randomised in pairs to treatment with either APS or GS. Five pairs of animals were killed 18 hours after the injection, 5 pairs 4 days after and 5 pairs 7 days after the injection and the platelet count, mean platelet volume, megakaryocyte nuclear, cytoplasmic and total size, megakaryocyte DNA distribution and the percentage of atheroma in the aorta were measured. Comparison of these variables between the 2 groups revealed the following statistically significant findings (p<0.05) : 18 hours after the injection the platelet count was decreased and the mean platelet volume increased in the APS group. At day 4 the platelet count, megakaryocyte nuclear, cytoplasmic and total size and the megakaryocyte DNA content were increased in the APS group. At day 7 the platelet count and the percentage of the atheroma were higher in the APS group. Since platelets produced by big megakaryocytes with high DNA content are more reactive than normal platelets, we suggest that the acceleration of atheroma formation demonstrated 7 days after APS is caused by the large number of platelets with possible high concentrations of growth factor(s) derived from the large megakaryocytes with increased DNA content.
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de la Salle, C., M. J. Baas, L. Grunebaum, R. Gialeraki, T. Mandalaki, and J.-P. Cazenave. "MOLECULAR ANALYSIS OF COAGULATION FACTOR VIII AND IX GENES BY DNA PROBES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643873.
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About 250 individuals belonging to 44 families with hemophilia A or B were studied in our laboratory. The detection of carriers was first established by pedigree analysis of each family . and coagulation and immunological assays of factor VIII or IX. The availability of specific probes for the molecular study of these two genes makes possible a diagnosis with certainty in the case of informative families. 25 families of hemophilia A were studied. For each person, blood was collected into EDTA and leucocyte DNA was extracted, digested by restriction endonucleases, electrophoresed in 0.9 % agarose gels and transferred to nitrocellulose filters by Southern blotting. Two probes were used for the analysis of factor VIII gene. The St 14 probe (J.L. Mandel) located on the q28 region of the X chromosome and closely linked to the gene, determines a restriction fragment length polymorphism (RFLP) when the DNA is digested by the enzyme TaqI. The p114-12 genomic probe (Genentech) corresponding to the exons 17 and 18 of the factor VIII gene, reveals a RFLP in the DNA digested by the enzyme BclI. 19 families -of hemophilia B were studied. A total factor IX cDNA probe was used for the screening of potential deletions in the case of hemophiliacs with circulating antibodies. A genomic probe containing the exons II, III and IV of factor IX was used to detect the TaqI RFLP. For the study of factor VIII gene, the extragenic probe St 14 gives a very high percentage of informativity (about 90 %) but recombination can occur between the probe and the gene. The p 114-12 probe, which is used to confirm the results given by the St 14 probe, gives about 20 % informativity. In our study, we were able to diagnose carrier state with certainty in 92 % of the families. For hemophilia B, the genomic probe gives about 40 % informativity. A large deletion of the region of the factor IX gene has been found in one family and remains to be mapped. In conclusion, carrier detection and prenatal diagnosis can be established with certainty by molecular studies in most cases of hemophilia A using the St 14 probe, with a 5 % risk of recombination when the BclI RFLP cannot confirm. This diagnosis is possible in about 40 % of the cases of hemophilia B.
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Eltai, Nahla Omer, Hadi M. Yassine, Sara H. Al-Hadidi, Tahra ElObied, Asmaa A. Al Thani, and Walid Q. Alali. "Retail Chicken Carcasses as a Reservoir of Antimicrobial- Resistant Escherichia coli." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0115.
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The dissemination of antimicrobial resistance (AMR) bacteria has been associated with the inappropriate use of antibiotics in both humans and animals and with the consumption of food contaminated with resistant bacteria. In particular, the use of antibiotics as prophylactic and growth promotion purposes in food-producing animals has rendered many of the antibiotics ineffective. The increased global prevalence of AMR poses a significant threat to the safety of the world’s food supply. Objectives: This study aims at determining the prevalence of antibiotic-resistant Escherichia coli (E. coli) isolated from local and imported retail chicken meat in Qatar. Methodology: A total of 270 whole chicken carcasses were obtained from three different hypermarket stores in Qatar. A total of 216 E. coli were isolated and subjected to antibiotic susceptibility testing against 18 relevant antibiotics using disc diffusion and micro- dilution methods. Furthermore, extended-spectrum β-lactamase (ESBL) production was determined via a double-disc synergetic test. Isolates harboring colistin resistance were confirmed using multiplex-PCR and DNA sequencing. Results: Nearly 89% (192/216) of the isolates were resistant to at least one antibiotics. In general, isolates showed relatively higher resistance to sulfamethoxazole (62%), tetracycline (59.7%), ampicillin and trimethoprim (52.3%), ciprofloxacin (47.7%), cephalothin, and colistin (31.9%). On the other hand, less resistance was recorded against amoxicillin/clavulanic acid (6%), ceftriaxone (5.1%), nitrofurantoin (4.2%) and piperacillin/tazobactam (4.2%), cefepime (2.3%), meropenem (1.4%), ertapenem (0.9%), and amikacin (0.9%). Nine isolates (4.2%) were ESBL producers. Furthermore, 63.4% were multidrug-resistant (MDR). The percentage of MDR, ESBL producers, and colistin-resistant isolates was significantly higher among local isolates compared to imported chicken samples. Conclusion: We reported a remarkably high percentage of the antibiotic-resistant E. coli in chicken meat sold at retail in Qatar. The high percentage of MDR and colistin isolates is troublesome to the food safety of raw chicken meat and the potential of antibiotic resistance spread to public health. Our findings support the need for the implementation of one health approach to address the spread of antimicrobial resistance and the need for a collaborative solution.
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Richters, H., L. Rademakers, B. Rajsekhar, H. Braam, C. Versteegh, and F. Wubben. "System Control Based on a State Model Specifying, Design-In and Measuring of the Availability." In ASME 2002 Wind Energy Symposium. ASMEDC, 2002. http://dx.doi.org/10.1115/wind2002-51.
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In the IEC 61400-12 standard “Wind turbine power performance testing”, the availability of a wind turbine is defined as: “the ratio of the total number of hours during a certain period, excluding the number of hours that the wind turbine could not be operated due to maintenance or fault situations, to the total number of hours in the period, expressed as a percentage” [1]. It seems to be a clear definition, however in practice all parties involved, and often commercially bounded by guarantees, cannot interpret it unambiguously. This has all to do with the fact that the actual measuring and tracking is not done in a structured manner, mainly because it is not clear what the various (sub-)states of a wind turbine can be, and which sub-states have to be considered as available or not, and also for discerning who is liable. Moreover, due to heavy operation conditions and potential unintended built-in weaknesses, the ultimate availability of a wind turbine measured over the lifetime of 20 years, can easily tail off by 10% to 25%. Directly related to availability, the return on investment (ROI) will even decrease with a higher proportional part. Consequently, availability is a serious issue for manufacturers and investors, and may have extensive commercial implications. To better understand and improve the availability, from the beginning of the design process, this article presents the ‘State Model for Wind Turbines’. It underpins the strategy to optimize the availability versus the total costs. Furthermore the article provides some practical tools for specifying, design-in and measuring of the final availability.
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Maroo, Shalabh C., H. Jeremy Cho, and Evelyn N. Wang. "Wetting Characteristics of a Phospholipid Membrane Using Molecular Dynamics Simulation." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40671.
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Phospholipid molecules form bilayers in water due to their hydrophilic heads and hydrophobic tails. The electroporation of lipid bilayers (cell membranes) is a phenomenon where membranes are permeabilized by the application of electric fields. At some critical voltage, a dramatic increase in conductivity across the membranes is observed. This phenomenon is widely used in DNA and RNA transfer as well as targeted drug delivery systems. However, the membrane ruptures with a continuous increase in voltage where interaction between lipid and water molecules is an important factor in electroporation behavior. This study characterizes the wettability, of both the head and tail groups of lipid molecules, by calculating the contact angle of a water droplet on a planar phospholipid monolayer using molecular dynamics simulations. The water droplet completely spreads on the hydrophilic heads of the lipid, while forming an average contact angle of 136.05° on the hydrophobic tails. An analysis using the Young’s equation suggests that a difference in free energy of 116 mJ/m2 contributes to the overall energy barrier for water penetration across the lipid monolayer. We aim to control this permeabilization phenomenon to achieve water desalination.
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Rasponi, Marco, Monica Soncini, Franco Maria Montevecchi, and Alberto Redaelli. "Numerical Analyses of Microchannels Filling in a Lab-on-Chip Device." In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95677.
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A prototype of a Lab-on-Chip (LoC) device manufactured by ST Microelectronics Inc., which is intended to be a diagnostic platform for DNA analysis, has been analyzed. In particular, the dynamics of the filling process was evaluated by means of a 3-D numerical model. Measurements of wettability were also conducted by evaluating the surface tension of the examined liquids and their contact angles on the solid substrates. Two different filling conditions were simulated: pure capillarity and a pressure of 1.5 kPa applied to the inlet. Results in terms of filling time, fluids velocities and percentage of air entrapped in the channels were analyzed. The numerical model revealed the presence of 3.4% of air in the channels (localized in the corner regions), when the pressure of 1.5 kPa was applied. In case of zero pressure, the top corners of the central channel got completely wetted, thus reducing the amount of air to 2.7%. The results showed that capillary forces are dominant during the filling of channels with dimensions smaller than 200 μm. General parameters used to have an insight into the kind of forces leading a fluid-dynamic process are the Reynolds (Re) and Capillary (Ca) numbers, ratios between inertial and viscous forces, and viscous and surface forces, respectively. The computed maximum values in our simulations were Re = 60 and Ca = 0.018, showing the predominance of surface forces on both viscous and, indirectly, inertial ones.
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Sarver, Nava, and George A. Ricca. "SUSTAINED EXPRESSION OF FULL LENGTH AND VARIANT RECOMBINANT FACTOR VIII IN GENETICALLY ENGINEERED CELLS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643875.
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A major effort is presently underway to provide factor VIII (FVIII) in a form free of viral pathogens via a recombinant DNA approach. We have constructed two chimeric FVIII cDNA vectors based on the bovine papillomavirus mammalian expression system. The first vector (FVIII) contained a full length FVIII cDNA; the second vector (AFVIII) contained a cDNA insert with an extensive deletion, corresponding to amino acid residues 747 to 1560 in the region encoding the "B" domain. This internal region is removed during activation of the parental FVIII molecule and is believed not to be required for coagulant activity. We have found that recombinant FVIII produced by stable cell lines harboring either the full length or the variant FVIII was capable of restoring coagulant activity to FVIII deficient plasma in. vitro. This expressed activity was neutralized by anti-FVIII antibodies. Similar to observations with FVIII derived from human plasma, the two recombinant FVIII forms were (i) inactivated by the chelating agent EDTA, (ii) demonstrated a biphasic response of an initial activation followed by a decay in activity when treated with thrombin, and (iii) presented the expected peptide banding pattern by western blot analyses. A higher percentage of ΔFVIII transformants were isolated expressing coagulant activity compared to transformants harboring the complete FVIII cDNA. Among the positive transformants isolated, those harboring ΔFVIII produced higher levels of coagulant activity than their full length counterparts. Comparable steady state levels of FVIII specific transcripts were detected in FVIII and ΔFVIII transformants indicating that the difference in expression levels is due to a post transcriptional event(s). Our study demonstrates the efficacy of a full length and an abridged recombinant FVIII produced by stably transformed cells in correcting coagulation deficiency in. vitro. It further suggests the potential usefulness of other molecular variants for efficient expression in genetically engineered cells.
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Hoffman, R., B. J. Roth, G. W. Sledge, J. Straneva, and J. Brandt. "ANALYSIS OF PHORBOL ESTER STIMULATED HUMAN MEGAKARYOCYTE DEVELOPMENT." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642951.
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The events that occur during the terminal maturation of human megakaryocytes are poorly characterized. To examine these events, a recently characterized human megakaryocytic cell line (EST-IU, Cancer Res. 46: 2155-2159, 1986) was exposed to 12-0-tetradecanoyl-phorbol-13-acetate (TPA), as well as 2 non-transforming phorbol esters (4 alpha phorbol and 4 beta phorbol 12 alpha, 13 alpha diacetate) at the identical concentrations. Morphologic changes, including cellular attachment to untreated plastic or glass, occurred within 4 hrs of treatment with TPA. Treatment of EST-IU cells with either of the 2 non-transforming phorbols (4-alpha phorbol, or 4-beta phorbol, 12-beta, 13-alpha diacetate) failed to change morphology, DNA content, or expression of surface membrane glycoproteins or alpha-granule constituents when compared to control cells. TPA treatment resulted, however, in j^rofound changes in adherence to plastic by the EST-IU cells, with an obvious dose-response relationship. At a 5 × 10-8 M TPA, cellular attachment was noted as early as 4 hours following treatment, agd was complete by 16 hours, at which time > 95% of treated cells were attached. Following TPA treatment at 5 × 10-8 M, a number of morphologic changes occurred, including marked cellular flattening, the appearance of extensive cytoplasmic budding, and the development of numerous filopodia. Cells treated with either of the non-transforming phorbols as assessed by propidium iodide staining and flow cytometric analysis failed to exhibit a change in ploidy, although TPA reproducibly altered this parameter of megakaryocyte development. Cells treated with 10-9 M TPA have approximately the same proportion of cells in the 4N and 8N peaks as control cells. Following exposure to 10-9 M and 10-8 M TPA, there was an apparent shift of cells out of the 4N peak to 8N and 16N levels, and even the appearance of a small percentage of 32N cells. The DNA content of TPA-treated cells was also assessed by Feulgen staining and microdensitome try. Those cells (5%) which failed to adhere following TPA treatment were analyzed separately, and showed a very different ploidy distribution than the adherent cell population. Over 85% of adherent cells have a ploidy > 16N, with some cells attaining the 128N level. Treatment of cells with either of the 2 non-transforming phorbols failed to affect the expression of Factor V, Factor VIIIrRAg, beta-throraboglobulin, fibrinogen, or platelet glycoproteins. Cells treated with 5 × 10-8 M TPA similarly do not significantly increse the expression of Factor V, fibrinogen, or beta-thromoglobulin over that observed in control cells. The expression of both Factor VIIIrRAg and platelet glycoproteins however, increase in TPA-treated cells. A similar increase in the expression of platelet glycoprotein Ilb/IIIA using the mouse monoclonal C17 was also observed. Those cells that express the highest levels of Factor VIII:RAg and platelet glycoproteins following phorbol treatment also demonstrated the highest ploidy levels and also are the largest cells as measured by forward angle light scatter during flow cytometry.These studies indicate that TPA treatment of EST-IU cells initiates a cascade of events characterized by cellular adherence, increases in cell size and DNA content, and enhanced expression of platelet glycoproteins and Factor VIIIrRAg. These events appear to occur in concert and closely resemble information that is available concerning maturation of normal rodent and human megakaryocytes. Although it is important to emphasize that EST-IU cells are leukemic and thus intrinsically different from normal human megakaryocytes, their availability and dynamic responses to TPA will provide an appropriate cellular model with which to study megakaryocyte maturation.