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871.
For reasons that are not yet clear, male aggression against females occurs frequently among primates with promiscuous mating systems. Here, we test the sexual coercion hypothesis that male aggression functions to constrain female mate choice. We use 10 years of behavioural and endocrine data from a community of wild chimpanzees (Pan troglodytes schweinfurthii) to show that sexual coercion is the probable primary function of male aggression against females. Specifically, we show that male aggression is targeted towards the most fecund females, is associated with high male mating success and is costly for the victims. Such aggression can be viewed as a counter-strategy to female attempts at paternity confusion, and a cost of multi-male mating.  相似文献   
872.
Influenza viruses attach to host cells by binding to terminal sialic acid (Neu5Ac) on glycoproteins or glycolipids. Both the linkage of Neu5Ac and the identity of other carbohydrates within the oligosaccharide are thought to play roles in restricting the host range of the virus. In this study, the receptor specificity of an H5 avian influenza virus haemagglutinin protein that has recently infected man (influenza strain A/Vietnam/1194/04) has been probed using carbohydrate functionalised poly(acrylic acid) polymers. A baculovirus expression system that allows facile and safe analysis of the Neu5Ac binding specificity of mutants of H5 HA engineered at sites that are predicted to effect a switch in host range has also been developed.  相似文献   
873.
The identification and exploration of a novel, potent and selective series of N-(3-cyano-4,5,6,7-tetrahydro-1-benzothien-2-yl)amide inhibitors of JNK2 and JNK3 kinases is described. Compounds 5a and 11a were identified as potent inhibitors of JNK3 (pIC50 6.7 and 6.6, respectively), with essentially equal potency against JNK2 (pIC50 6.5). Selectivity within the mitogen-activated protein kinase (MAPK) family, against JNK1, p38alpha and ERK2, was observed for the series. X-ray crystallography of 5e and 8a in JNK3 revealed a unique binding mode, with the 3-cyano substituent forming an H-bond acceptor interaction with the hinge region of the ATP-binding site.  相似文献   
874.
Genital human papillomavirus (HPV) infection is the most common sexually transmitted infection, and virtually all cases of cervical cancer are attributable to infection by a subset of HPVs (reviewed in ref. 1). Despite the high incidence of HPV infection and the recent development of a prophylactic vaccine that confers protection against some HPV types, many features of HPV infection are poorly understood. It remains worthwhile to consider other interventions against genital HPVs, particularly those that target infections not prevented by the current vaccine. However, productive papillomavirus infection is species- and tissue-restricted, and traditional models use animal papillomaviruses that infect the skin or oral mucosa. Here we report the development of a mouse model of cervicovaginal infection with HPV16 that recapitulates the establishment phase of papillomavirus infection. Transduction of a reporter gene by an HPV16 pseudovirus was characterized by histology and quantified by whole-organ, multispectral imaging. Disruption of the integrity of the stratified or columnar genital epithelium was required for infection, which occurred after deposition of the virus on the basement membrane underlying basal keratinocytes. A widely used vaginal spermicide, nonoxynol-9 (N-9), greatly increased susceptibility to infection. In contrast, carrageenan, a polysaccharide present in some vaginal lubricants, prevented infection even in the presence of N-9, suggesting that carrageenan might serve as an effective topical HPV microbicide.  相似文献   
875.
We show that an innate defense-regulator peptide (IDR-1) was protective in mouse models of infection with important Gram-positive and Gram-negative pathogens, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus and Salmonella enterica serovar Typhimurium. When given from 48 h before to 6 h after infection, the peptide was effective by both local and systemic administration. Because protection by IDR-1 was prevented by in vivo depletion of monocytes and macrophages, but not neutrophils or B- and T-lymphocytes, we conclude that monocytes and macrophages are key effector cells. IDR-1 was not directly antimicrobial: gene and protein expression analysis in human and mouse monocytes and macrophages indicated that IDR-1, acting through mitogen-activated protein kinase and other signaling pathways, enhanced the levels of monocyte chemokines while reducing pro-inflammatory cytokine responses. To our knowledge, an innate defense regulator that counters infection by selective modulation of innate immunity without obvious toxicities has not been reported previously.  相似文献   
876.
Lampropholis guichenoti is an oviparous lizard that lays eggs with a calcareous outer shell. We used immunofluorescence microscopy to describe the occurrence and distribution of Ca2+ ATPase pumps in the uterus of L. guichenoti at different stages of the reproductive and egg-shelling cycles. Ca2+ ATPase pumps were not demonstrated by immunofluorescent techniques in any uterine tissue until egg-shelling had commenced and at least partly calcified eggs were in the uterus. During egg-shelling, Ca2+ ATPase pumps occur on the apical and baso-lateral surfaces of uterine epithelial cells, and those of associated shell glands in the stroma of the uterus. We conclude that Ca2+ ATPase pumps provide a major mechanism for deposition of the calcareous eggshell of L. guichenoti and that the pumps are up-regulated when required in the reproductive cycle. Furthermore, it is likely that specific calcium glands in the stroma of the uterus are involved in the rapid transport required for egg-shelling, but the differential contribution of luminal and glandular epithelial cells is not known.  相似文献   
877.
We prepare a biotinylated conjugate of the ubiquitous plant hormone (S)-(+)-abscisic acid via an acyl hydrazone linkage at the C4' position and demonstrate in vivo cleavage of the otherwise stable acyl hydrazone linkage using LC-MS2. As part of a wider chemical genomic study, biological activity of the conjugate was assessed using standard epidermal peel and gravimetric transpiration assays, showing significant activity but at a level lower than the unconjugated hormone. When deuterated samples of the conjugate were fed to the plant, however, it was apparent by LC-MS2 experiments that significant levels of hydrolysis of the acyl hydrazone had taken place, contrary to in vitro stability assays in artificial sap. We conclude that abscisic acid is liberated in sufficient quantities to account for the observed physiological response and that LC-MS2 monitoring of conjugates is a simple and practical method by which such events may be assessed, whether in plants or other organisms.  相似文献   
878.
879.
Functional training programs have been used in a variety of rehabilitation settings with documented success. Based on that success, the concept of functional training has gained popularity in applied fitness settings to enhance sport performance. However, there has been little or no research studying the efficacy of functional training programs on the improvement of sport performance or functional fitness. Thus, it was the purpose of this study to determine the effect of a progressive functional training program on club head speed and functional fitness in older male golfers. Eighteen male golfers (age: 70.7 +/- 9.1 [SD] years) were randomly assigned to an exercise (N = 11) or control (N = 7) group. The exercise group participated in an 8-week progressive functional training program including flexibility exercises, core stability exercises, balance exercises, and resistance exercises. Pre- and postmeasurements included club head speed of a driver by radar (exercise and Control) and Fullerton Senior Fitness Test measurements (exercise only). One-way analysis of covariance was performed on club head speed measurements using pretest measurements as the covariate. Paired t-tests were performed to analyze Senior Fitness Test variables. After the intervention, maximal club head speed increased in the exercise group (127.3 +/- 13.4 to 133.6 +/- 14.2 km x hr(-1)) compared with the control group (134.5 +/- 14.6 to 133.3 +/- 11.2 km x hr(-1); p < 0.05). Additionally, improvements (p < 0.05) were detected for most Senior Fitness Test variables in the exercise group. In summary, this functional training program resulted in significant improvements in club head speed and several components of functional fitness. Future research should continue to examine the effect of functional training programs on sport performance and functional fitness in older adults.  相似文献   
880.
DNA obtained from museum specimens provides a historical perspective on levels of genetic diversity. Archived samples are irreplaceable so it is desirable that only parts of the specimens are used, which constrains the amount of DNA obtained from small taxa. However, at present there are no quantitative data on yields of DNA from such samples. In this paper we determine the amount of DNA that may be extracted from the legs of museum-archived specimens of the damselfly Coenagrion mercuriale (Charpentier) and the suitability of this DNA for PCR-amplification of nuclear genetic loci (microsatellites). We find that (i) the yield of DNA correlates with the genotyping success rate and (ii) the amount of DNA obtained from the legs decreases with time since sample collection until 1954, before which no DNA could be detected (although DNA may be present in very low quantities). This cut-off point for successful DNA extraction corresponds with the date until reliable genotypes could be obtained by routine PCR. Thus, air-dried insect legs more than 50 years old appear to have limited usefulness for studies that seek to amplify many nuclear loci without the use of other techniques that may be used to increase the possible low-quantities of template DNA present.  相似文献   
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