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1.
Ian G. Macreadie Chinniah K. Arunagiri Dean R. Hewish Jacinta F. White A. A. Azad 《Molecular microbiology》1996,19(6):1185-1192
Vpr is a virion-associated protein of human immuno-deficiency virus type 1 (HIV-1) whose function in acquired immune deficiency syndrome (AIDS) has been uncertain. We previously employed yeast as a model to examine the effects of Vpr on basic cellular functions; intracellular Vpr was shown to cause cell-growth arrest and structural defects, and these effects were caused by a region of Vpr containing the sequence HFRIGCRHSRIG. Here we show that peptides containing the H(S/F)RIG amino acid sequence motif cause death when added externally to a variety of yeast including Saccharomyces cerevisiae, Kluyveromyces lactis, Candida glabrata, Candida albicans and Schizosaccharomyces pombe. Such peptides rapldly entered the cell from the time of addition, resulting in cell death. Elevated levels of ions, particularly magnesium and calcium ions, abrogated the cytotoxic effect by preventing the Vpr peptides from entering the cells. Extracellular Vpr found in the serum, or breakdown products of extracellular Vpr, may have similar effects to the Vpr peptides described here and could explain the death of uninfected by-stander cells during AIDS. 相似文献
2.
Shannon P. Smyth Brett Nixon Amanda L. Anderson Heather C. Murray Jacinta H. Martin Lily A. MacDougall Sarah A. Robertson David A. Skerrett-Byrne John E. Schjenken 《Proteomics》2022,22(9):2100227
The seminal vesicles are male accessory sex glands that contribute the major portion of the seminal plasma in which mammalian spermatozoa are bathed during ejaculation. In addition to conveying sperm through the ejaculatory duct, seminal vesicle secretions support sperm survival after ejaculation, and influence the female reproductive tract to promote receptivity to pregnancy. Analysis of seminal vesicle fluid (SVF) composition by proteomics has proven challenging, due to its highly biased protein signature with a small subset of dominant proteins and the difficulty of solubilizing this viscous fluid. As such, publicly available proteomic datasets identify only 85 SVF proteins in total. To address this limitation, we report a new preparative methodology involving sequential solubilization of mouse SVF in guanidine hydrochloride, acetone precipitation, and analysis by label-free mass spectrometry. Using this strategy, we identified 126 SVF proteins, including 83 previously undetected in SVF. Members of the seminal vesicle secretory protein family were the most abundant, accounting for 79% of all peptide spectrum matches. Functional analysis identified inflammation and formation of the vaginal plug as the two most prominent biological processes. Other notable processes included modulation of sperm function and regulation of the female reproductive tract immune environment. Together, these findings provide a robust methodological framework for future SVF studies and identify novel proteins with potential to influence both male and female reproductive physiology. 相似文献
3.
Colussi F Serpa V Delabona Pda S Manzine LR Voltatodio ML Alves R Mello BL Pereira N Farinas CS Golubev AM Santos MA Polikarpov I 《Journal of microbiology and biotechnology》2011,21(8):808-817
Because of its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum has a considerable potential in biomass hydrolysis applications. Trichoderma harzianum cellobiohydrolase I (ThCBHI), an exoglucanase, is an important enzyme in the process of cellulose degradation. Here, we report an easy single-step ion-exchange chromatographic method for purification of ThCBHI and its initial biophysical and biochemical characterization. The ThCBHI produced by induction with microcrystalline cellulose under submerged fermentation was purified on DEAE-Sephadex A-50 media and its identity was confirmed by mass spectrometry. The ThCBHI biochemical characterization showed that the protein has a molecular mass of 66 kDa and pI of 5.23. As confirmed by smallangle X-ray scattering (SAXS), both full-length ThCBHI and its catalytic core domain (CCD) obtained by digestion with papain are monomeric in solution. Secondary structure analysis of ThCBHI by circular dichroism revealed alpha- helices and beta-strands contents in the 28% and 38% range, respectively. The intrinsic fluorescence emission maximum of 337 nm was accounted for as different degrees of exposure of ThCBHI tryptophan residues to water. Moreover, ThCBHI displayed maximum activity at pH 5.0 and temperature of 50 degrees C with specific activities against Avicel and p-nitrophenyl-β-D-cellobioside of 1.25 U/mg and 1.53 U/mg, respectively. 相似文献
4.
Genetic and paleomodelling evidence of the population expansion of the cattle egret Bubulcus ibis in Africa during the climatic oscillations of the Late Pleistocene
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Carlos Congrains Antônio F. Carvalho Elder A. Miranda Graeme S. Cumming Dominic A. W. Henry Shiiwua A. Manu Jacinta Abalaka Cristiano D. Rocha Moussa S. Diop Joãozinho Sá Hamilton Monteiro Lars H. Holbech Francis Gbogbo Silvia N. Del Lama 《Journal of avian biology》2016,47(6):846-857
Increasing aridity during glacial periods produced the retraction of forests and the expansion of arid and semi‐arid environments in Africa, with consequences for birds. Cattle egret Bubulcus ibis is a dispersive species that prefers semi‐arid environments and requires proximity to bodies of water. We expected that climatic oscillations led to the expansion of the range of the cattle egret during arid periods, such as the Last Maximum Glacial (LGM) and contraction of distribution during the Last Interglacial (LIG) period, resulting in contact of populations previously isolated. We investigated this hypothesis by evaluating the genetic structure and population history of 15 cattle egret breeding colonies located in west and South Africa using the mitochondrial DNA (mtDNA) control region, mtDNA ATPase 8 and 6, and an intron of nuclear gene transforming growth factor‐beta 2. Occurrence data and bioclimatic information were used to generate ecological niche models of three periods (present, LGM and LIG). We used the genetic and paleomodelling data to assess the responses of the cattle egret from Africa to the climatic oscillations during the late Pleistocene. Genetic data revealed low levels of genetic differentiation, signs of isolation‐by‐distance, as well as recent increases in effective population size that started during the LGM. The observed low genetic structure may be explained by recent colonization events due to the demographic expansion following the last glacial period and by dispersal capacity of this species. The paleomodels corroborated the expansion during the LGM, and a more restricted potential distribution during the LIG. Our findinds supports the hypothesis that the species range of the cattle egret expanded during arid periods and contracted during wet periods. 相似文献
5.
Evan T. Sloan Jacinta C. Beehner Thore J. Bergman Amy Lu Noah SnyderMackler Hans Jacquemyn 《Ecology and evolution》2022,12(3)
Nonhuman primates are an essential part of tropical biodiversity and play key roles in many ecosystem functions, processes, and services. However, the impact of climate variability on nonhuman primates, whether anthropogenic or otherwise, remains poorly understood. In this study, we utilized age‐structured matrix population models to assess the population viability and demographic variability of a population of geladas (Theropithecus gelada) in the Simien Mountains, Ethiopia with the aim of revealing any underlying climatic influences. Using data from 2008 to 2019 we calculated annual, time‐averaged, and stochastic population growth rates (λ) and investigated relationships between vital rate variability and monthly cumulative rainfall and mean temperature. Our results showed that under the prevailing environmental conditions, the population will increase (λ s = 1.021). Significant effects from rainfall and/or temperature variability were widely detected across vital rates; only the first year of infant survival and the individual years of juvenile survival were definitively unaffected. Generally, the higher temperature in the hot‐dry season led to lower survival and higher fecundity, while higher rainfall in the hot‐dry season led to increased survival and fecundity. Overall, these results provide evidence of greater effects of climate variability across a wider range of vital rates than those found in previous primate demography studies. This highlights that although primates have often shown substantial resilience to the direct effects of climate change, their vulnerability may vary with habitat type and across populations. 相似文献
6.
Amy Lu Carola Borries Nancy M. Czekala Jacinta C. Beehner 《American journal of primatology》2010,72(12):1073-1081
Understanding female reproductive characteristics is important for assessing fertility, interpreting female behavior, and designing appropriate conservation and captive management plans. In primate species lacking morphological signs of receptivity, such as most colobines, determination of reproductive parameters depends on the analysis of reproductive hormones. Here, we use fecal hormone analysis to characterize cycle patterns (N=6 females) and gestation length (N=7 females) in a group of wild Phayre's leaf monkeys (Trachypithecus phayrei crepusculus) in Phu Khieo Wildlife Sanctuary, Thailand. We found that both fecal estrogen (fE) and progestin (fP) levels showed clear biological patterns indicative of ovulation and conception. However, because fP patterns were inadequate in determining the end of the luteal phase, we used fE rather than fP patterns to delineate menstrual cycle parameters. We found a mean cycle length of 28.4 days (N=10), with follicular and luteal phases of 15.4 (N=10) and 12.5 days (N=14), respectively. On average, females underwent 3.57 (N=7) cycles until conception. Average gestation length was 205.3 days (N=7), with fE levels increasing over the course of pregnancy. Overall, the reproductive characteristics found for Phayre's leaf monkeys were consistent with results for other colobine species, suggesting that fecal hormone monitoring, particularly for fE metabolites, can provide useful reproductive information for this species. Am. J. Primatol. 72:1073–1081, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
7.
Ian G. Macreadie PhD Ross Fernley Laura A. Castelli Anna Lucantoni Jacinta White A. Azad 《Journal of biomedical science》1998,5(3):203-210
The human immunodeficiency virus type 1 (HIV-1) Nef protein is essential for AIDS pathogenesis, but its function remains highly controversial. During stresses such as growth in the presence of copper or at elevated temperature, myristylated Nef is released from yeast cells and, after extended culture in stationary phase, it accumulates in the supernatant as a dense membranous material that can be centrifuged into a discrete layer above the cell pellet. This material is unique to Nef-producing cells and represents a convenient source of Nef that may have application in further biological studies. Within the yeast cell, electron microscopic examination shows that Nef localises in novel, membrane-bound bodies. These data support the evidence for a role of Nef in membrane perturbation and suggest that there may be a similar localisation for myristylated Nef in HIV-1 infected cells. 相似文献
8.
In vitro antifungal activity of miltefosine and levamisole: their impact on ergosterol biosynthesis and cell permeability of dimorphic fungi
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9.
David J. Pappano Eila K. Roberts Jacinta C. Beehner 《American journal of primatology》2010,72(11):934-941
Four experiments were conducted to test different aspects of a “field‐friendly” fecal hormone extraction method that utilizes methanol extraction in the field followed by storage on C18 solid‐phase extraction cartridges. Fecal samples were collected from geladas (Theropithecus gelada) housed at the Bronx Zoo, and the experiments were conducted in a laboratory setting to ensure maximum control. The experiments were designed to either simulate the conditions to which fecal samples are subjected during fieldwork or improve on an existing protocol. The experiments tested the relationship between fecal hormone metabolite preservation/recovery and: (1) the amount of time a sample is stored at ambient temperature; (2) the number of freeze/thaw cycles a sample undergoes; (3) the effectiveness of different extraction solutions; and (4) the effectiveness of different cartridge washes. For each experiment, samples were assayed by radioimmunoassay for fecal glucocorticoid (GC) and testosterone (T) metabolites. Results for each of the experiments were as follows. First, storage at ambient temperature did not affect hormone levels until 4 weeks of storage, with significant increases for both GC and T metabolites at 4 weeks. Second, hormone levels significantly decreased in samples after two freeze/thaw cycles for GCs and six freeze/thaws cycles for T. Third, for both GCs and T, hormone extraction using various methanol solutions was significantly higher than using 100% ethanol. Finally, using a 20% methanol solution to wash cartridges significantly increased GC levels but had no effect on T levels. These results suggest that, when utilizing C18 cartridges for fecal steroid storage, researchers should consider several methodological options to optimize hormone preservation and recovery from fecal samples. Am. J. Primatol. 72:934–941, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
10.
Shae B. Padrick Jacinta L. Chuang David T. Chuang Michael V. Norgard Chad A. Brautigam 《Analytical biochemistry》2010,407(1):89-23488
Determination of the stoichiometry of macromolecular assemblies is fundamental to an understanding of how they function. Many different biophysical methodologies may be used to determine stoichiometry. In the past, both sedimentation equilibrium and sedimentation velocity analytical ultracentrifugation have been employed to determine component stoichiometries. Recently, a method of globally analyzing multisignal sedimentation velocity data was introduced by Schuck and coworkers. This global analysis removes some of the experimental inconveniences and inaccuracies that could occur in the previously used strategies. This method uses spectral differences between the macromolecular components to decompose the well-known c(s) distribution into component distributions ck(s); that is, each component k has its own ck(s) distribution. Integration of these distributions allows the calculation of the populations of each component in cosedimenting complexes, yielding their stoichiometry. In our laboratories, we have used this method extensively to determine the component stoichiometries of several protein-protein complexes involved in cytoskeletal remodeling, sugar metabolism, and host-pathogen interactions. The overall method is described in detail in this work, as are experimental examples and caveats. 相似文献