The effects of a long-term psychosocial stress on reproductive indicators in the baboon

Psychosocial stress is thought to negatively impact fecundity, but human studies are confounded by variation in nutrition and lifestyle. Baboons offer a useful model to test the effect of prolonged mild stress on reproductive indicators in a controlled setting. Following relocation from social groups to solitary housing, a previously documented stressful event for nonhuman primates, daily urine samples, tumescence, and menstrual bleeding were monitored in twenty baboons (Papio sp.) for 120-150 days. Specimens were assayed for estrone conjugates (E1C), pregnanediol-3-glucuronide (PDG), follicle-stimulating hormone (FSH), and cortisol. Linear mixed effects models examined (1) the effects of stress on frequency of anovulation, hormone levels, tumescence and cycle length, and (2) the relationship of cortisol with reproductive indicators. Despite cortisol levels indicative of stress, anovulation was negligible (1% in 102 cycles). PDG, FSH, cycle length, and tumescence declined during the first four cycles, but began recovery by the fifth. Cortisol was negatively associated with FSH but not associated with PDG, E1C or tumescence. Ovulation, E1C, and luteal phase length were not affected. Tumescence tracked changes in FSH and PDG, and thus may be a useful indicator of stress on the reproductive axis. Elevated cortisol was associated with reduced FSH, supporting a model of cortisol action at the hypothalamus rather than the gonad. After four to five menstrual cycles the reproductive indicators began recovery, suggesting adjustment to new housing conditions. In conclusion, individual housing is stressful for captive baboons, as reflected by cortisol and reproductive indicators, although ovulation, a relatively direct proxy for fecundity, is unaffected.     

Fine-scale mapping of natural variation in fly fecundity identifies neuronal domain of expression and function of an aquaporin

To gain insight into the molecular genetic basis of standing variation in fitness related traits, we identify a novel factor that regulates the molecular and physiological basis of natural variation in female Drosophila melanogaster fecundity. Genetic variation in female fecundity in flies derived from a wild orchard population is heritable and largely independent of other measured life history traits. We map a portion of this variation to a single QTL and then use deficiency mapping to further refine this QTL to 5 candidate genes. Ubiquitous expression of RNAi against only one of these genes, an aquaporin encoded by Drip, reduces fecundity. Within our mapping population Drip mRNA level in the head, but not other tissues, is positively correlated with fecundity. We localize Drip expression to a small population of corazonin producing neurons located in the dorsolateral posterior compartments of the protocerebrum. Expression of Drip-RNAi using both the pan-neuronal ELAV-Gal4 and the Crz-Gal4 drivers reduces fecundity. Low-fecundity RILs have decreased Crz expression and increased expression of pale, the enzyme encoding the rate-limiting step in the production of dopamine, a modulator of insect life histories. Taken together these data suggest that natural variation in Drip expression in the corazonin producing neurons contributes to standing variation in fitness by altering the concentration of two neurohormones.     

Proteomic analysis of blastema formation in regenerating axolotl limbs

Background

For membrane proteins, lipids provide a structural framework and means to modulate function. Paired connexin hemichannels form the intercellular channels that compose gap junction plaques while unpaired hemichannels have regulated functions in non-junctional plasma membrane. The importance of interactions between connexin channels and phospholipids is poorly understood.

Results

Endogenous phospholipids most tightly associated with purified connexin26 or connexin32 hemichannels or with junctional plaques in cell membranes, those likely to have structural and/or modulatory effects, were identified by tandem electrospray ionization-mass spectrometry using class-specific interpretative methods. Phospholipids were characterized by headgroup class, charge, glycerol-alkyl chain linkage and by acyl chain length and saturation. The results indicate that specific endogenous phospholipids are uniquely associated with either connexin26 or connexin32 channels, and some phospholipids are associated with both. Functional effects of the major phospholipid classes on connexin channel activity were assessed by molecular permeability of hemichannels reconstituted into liposomes. Changes to phospholipid composition(s) of the liposome membrane altered the activity of connexin channels in a manner reflecting changes to the surface charge/potential of the membrane and, secondarily, to cholesterol content. Together, the data show that connexin26 and connexin32 channels have a preference for tight association with unique anionic phospholipids, and that these, independent of headgroup, have a positive effect on the activity of both connexin26 and connexin32 channels. Additionally, the data suggest that the likely in vivo phospholipid modulators of connexin channel structure-function that are connexin isoform-specific are found in the cytoplasmic leaflet. A modulatory role for phospholipids that promote negative curvature is also inferred.

Conclusion

This study is the first to identify (endogenous) phospholipids that tightly associate with connexin channels. The finding that specific phospholipids are associated with different connexin isoforms suggests connexin-specific regulatory and/or structural interactions with lipid membranes. The results are interpreted in light of connexin channel function and cell biology, as informed by current knowledge of lipid-protein interactions and membrane biophysics. The intimate involvement of distinct phospholipids with different connexins contributes to channel structure and/or function, as well as plaque integrity, and to modulation of connexin channels by lipophilic agents.     

Genetic characterization of the complete genome of a highly divergent simian T-lymphotropic virus (STLV) type 3 from a wild Cercopithecus mona monkey

Background

RNA interference is a gene regulatory mechanism that employs small RNA molecules such as microRNA. Previous work has shown that HIV-1 produces TAR viral microRNA. Here we describe the effects of the HIV-1 TAR derived microRNA on cellular gene expression.

Results

Using a variation of standard techniques we have cloned and sequenced both the 5' and 3' arms of the TAR miRNA. We show that expression of the TAR microRNA protects infected cells from apoptosis and acts by down-regulating cellular genes involved in apoptosis. Specifically, the microRNA down-regulates ERCC1 and IER3, protecting the cell from apoptosis. Comparison to our cloned sequence reveals possible target sites for the TAR miRNA as well.

Conclusion

The TAR microRNA is expressed in all stages of the viral life cycle, can be detected in latently infected cells, and represents a mechanism wherein the virus extends the life of the infected cell for the purpose of increasing viral replication.     

Age-Specific Patterns of Genetic Variance in Drosophila Melanogaster. I. Mortality

PETER MEDAWAR proposed that senescence arises from an age-related decline in the force of selection, which allows late-acting deleterious mutations to accumulate. Subsequent workers have suggested that mutation accumulation could produce an age-related increase in additive genetic variance (V(A)) for fitness traits, as recently found in Drosophila melanogaster. Here we report results from a genetic analysis of mortality in 65,134 D. melanogaster. Additive genetic variance for female mortality rates increases from 0.007 in the first week of life to 0.325 by the third week, and then declines to 0.002 by the seventh week. Males show a similar pattern, though total variance is lower than in females. In contrast to a predicted divergence in mortality curves, mortality curves of different genotypes are roughly parallel. Using a three-parameter model, we find significant V(A) for the slope and constant term of the curve describing age-specific mortality rates, and also for the rate at which mortality decelerates late in life. These results fail to support a prediction derived from MEDAWAR's ``mutation accumulation' theory for the evolution of senescence. However, our results could be consistent with alternative interpretations of evolutionary models of aging.     

西双版纳尚勇自然保护区野生印支虎及其三种主要有蹄类猎物种群现状调查

中国野生印支虎及其猎物种群状况的野外实地研究一直处于空白。本研究使用足迹鉴别法、粪堆计数法,首次对西双版纳尚勇自然保护区野生印支虎种群数量现状及该区域内的虎猎物种群状况进行了调查研究。结果显示:2004 ～ 2009 年间,确认西双版纳保护区存在3 只成年印支虎个体(2 雌1 雄),西双版纳尚勇保护区拥有比较丰富的有蹄类种群,其中虎的主要猎物:水鹿平均密度为7.63 (7.40 ～ 9.23)只/ km² ;赤麂平均密度为17. 39 (11.33 ～24.94)只/ km² ,野猪平均密度为10.26 (7.69 ～ 14.51) 只/ km² ,该区域虎猎物生物量为1 715. 74 kg/ km² 。本研究还探讨了该区域印支虎种群的保护前景以及中国境内开展虎种群调查的适用办法等。     

A DNA vaccine against tuberculosis based on the 65 kDa heat-shock protein differentially activates human macrophages and dendritic cells

Background

Application of plasmid DNA for immunization of food-producing animals established new standards of food safety. The addition of foreign products e.g. pDNA into the food chain should be carefully examined to ensure that neither livestock animals nor consumers develop unpredicted or undesirable side-effects.

Methods

A quantitative real-time PCR (QRTPCR) methodology was developed to study the biodistribution and persistence of plasmid DNA vaccine pDNAX (pVAX-Hsp60 TM814) in mice and beef cattle. The linear quantification range and the sensitivity of the method was found to be 10 – 10⁹ copies per reaction (500 ng/gDNA) and 3 copies per reaction, respectively.

Results

Persistence of pDNAX in mice muscle tissue was restricted to injection site and the amount of pDNAX showed delivery formulation dependent (naked pDNA, electroporation, cationic liposome complexes) and mouse age-dependent clearance form injection site but pDNAX was still detectable even after 365 days. The QRTPCR analysis of various muscle tissue samples of vaccinated beef bulls performed 242–292 days after the last revaccination proved that residual pDNAX was found only in the injection site. The highest plasmid levels (up to 290 copies per reaction) were detected in the pDNAX:CDAN/DOPE group similarly to mice model. No pDNA was detected in the samples from distant muscles and draining lymph nodes.

Conclusion

Quantitative real-time PCR (QRTPCR) assay was developed to assess the residual pDNA vaccine pVAX-Hsp60 TM814 in mice and beef cattle. In beef cattle, ultra low residual level of pDNA vaccine was only found at the injection site. According to rough estimation, consumption of muscles from the injection site represents almost an undetectable intake of pDNA (400 fg/g muscle tissue) for consumers. Residual plasmid in native state will hardly be found at measurable level following further meat processing. This study brings supportive data for animal and food safety and hence for further approval of pDNA vaccine field trials.