Trees on networks: resolving statistical patterns of phylogenetic similarities among interacting proteins

Background  

Phylogenies capture the evolutionary ancestry linking extant species. Correlations and similarities among a set of species are mediated by and need to be understood in terms of the phylogenic tree. In a similar way it has been argued that biological networks also induce correlations among sets of interacting genes or their protein products.     

南瓜雌蕊与自花及远缘花粉的相互作用

南瓜柱头表面经去垢剂、蛋白酶及Con A处理后花粉不能萌发或花粉管生长受阻,Con A能专一地与柱头表面结合。柱头块加入培养液可促进花粉萌发。不同的远缘花粉授粉后在雌蕊不同部位受阻。在成熟南瓜雌蕊提取液中检测到血凝活性,凝集素可能参与雌蕊对远缘花粉的抑制。     

Postpartum anestrus in French beef cattle: an epidemiological study

Postpartum anestrus of lactating beef cows was studied by means of an epidemiological study carried out on 878 lactating beef cows in 60 French herds. The cows calved between October 1992 and March 1993 and were housed 2 mo after calving, when the anestrus status was determined by progesterone radioimmunoassays. Data analysis was performed using a multiple logistic model in order to adjust for confounding and interaction. Fifty-one percent of the primiparous and 23% of the multiparous cows were found to be in anestrus. Factors significantly related to anestrus were parity (primiparous); breed (Charolais); housing type (tie housing); suckling (compared to weaning at birth); and, among those that were under the control of the farmer, calving conditions (manual exploration of the birth canal); body condition score at calving (3 or less, on a 5-point scale); and loss in body condition score after calving (1 point or more within 2 mo). Previous reproductive performance for multiparous cows such as a long calving interval and induced estrus in the previous year also appeared to be related to anestrus.     

Determination of the time of ovulation in chimpanzees by measurement of LH, estrone sulfate, and pregnanediol 3 alpha-glucuronide in urine: comparison with serum hormone patterns.

The concentrations of LH, total estrogens, and pregnanediol 3 alpha-glucuronide (PdG) were determined by specific radioimmunoassays on daily overnight urine samples obtained in 13 menstrual cycles of six adult female chimpanzees during the periods of increasing, maximal, and decreasing tumescence of the perineal sex skin. The peaks of estrogens and LH and the rise in PdG in urine accurately reflected the peaks of estradiol-17 beta and LH and the subsequent rise in progesterone in the serum of the same animals during the same menstrual cycles, and can be used to predict and verify the occurrence of ovulation, thus avoiding the repeated tranquilizations necessary to obtain daily blood samples.     

Proteomic Analysis of the Reproductive Organs of the Hermaphroditic Gastropod Lymnaea stagnalis Exposed to Different Endocrine Disrupting Chemicals

Many studies have reported perturbations of mollusc reproduction following exposure to low concentrations (ng/L range) of endocrine disrupting chemicals (EDCs). However, the mechanisms of action of these molecules on molluscs are still poorly understood. Investigation of the modifications of protein expression in organisms exposed to chemicals using proteomic methods can provide a broader and more comprehensive understanding of adverse impacts of pollution on organisms than conventional biochemical biomarkers (e.g., heat-shock proteins, metallothioneins, GST, EROD). In this study we have investigated the impacts of four chemicals, which exhibit different endocrine disrupting properties in vertebrates, on the proteome of the hermaphroditic freshwater pulmonate gastropod Lymnaea stagnalis after 21 days of exposure. Testosterone, tributyltin, chlordecone and cyproterone acetate were chosen as tested compounds as they can induce adverse effects on the reproduction of this snail. The 2D-DIGE method was used to identify proteins whose expression was affected by these compounds. In addition to modifying the expression of proteins involved in the structure and function of the cytoskeleton, chemicals had impacts on the expression of proteins involved in the reproduction of L. stagnalis. Exposure to 19.2 µg/L of chlordecone increased the abundance of ovipostatin, a peptide transmitted during mating through seminal fluid, which reduces oviposition in this species. The expression of yolk ferritin, the vitellogenin equivalent in L. stagnalis, was reduced after exposure to 94.2 ng Sn/L of tributyltin. The identification of yolk ferritin and the modification of its expression in snails exposed to chemicals were refined using western blot analysis. Our results showed that the tested compounds influenced the abundance of yolk ferritin in the reproductive organs. Alteration in proteins involved in reproductive pathways (e.g., ovipostatin and yolk ferritin) could constitute relevant evidence of interaction of EDCs with reproductive pathways that are under the control of the endocrine system of L. stagnalis.