Size-fecundity relationships and reproductive investment in female frogs in the Pantanal, south-western Brazil

The ovarian complement of anurans exhibiting different reproductive modes is highly diverse, and intraspecific variation in reproductive output of anurans is generally related to variation in female properties and/or environmental conditions. The size-fecundity relationships, reproductive investment, and correlation between ovary mass and fat body mass were investigated for females of an anuran assemblage in the Pantanal, Brazil. Female body size was positively correlated with clutch size among seven of the eight species analyzed. However, these results seem to be influenced by seasonal variation in fecundity. Interspecific size-fecundity relationships revealed that female SVL was positively correlated with clutch size and egg size regardless of reproductive mode. Among 11 species analyzed, the reproductive investment (RI: ovary mass relative to body mass) varied from 5.5 to 18%, and there were no differences among reproductive modes and activity patterns (explosive/prolonged). RI correlated negatively with female size. Among three Leptodactylus species examined, negative correlation between ovary mass and fat body mass was verified for two species. Variations in the reproductive strategies are closely related to the reproductive activity patterns and reproductive modes exhibited by individual species, but are also influenced by environmental conditions. However, regardless of reproductive mode or activity pattern, each species seems to exhibit a reproductive strategy that allows them to respond differently to the same environmental restrictions.

Chronic renal failure in male and female rats

Gender influences the progression of chronic renal failure (CRF). We studied male (M) and female (F) Wistar rats for 90 days: castrated (CMc, n=7; CFc, n=6) and non castrated controls (CM, n=9; CF, n=6); castrated (CRFMc, n=8; CRFFc, n=6) and non castrated animals submitted to 5/6 nephrectomy (CRFM, n=13; CRFF, n=6). Data are expressed as mean ± SEM. Proteinuria (PTN) was higher in CRFM (554 ± 69mg/24h) compared to CRFMc (277 ± 85 mg/24h), but not in females (CRFF=193 ± 20mg/24h, CRFFc=164 ± 71mg/24h). Mesangial fractional volume increased in all CRF animals. CRF animals showed an increase of glomerular sclerosis index (GSI) and tubulointerstitial damage (TID) but in a smaller proportion in male castrated animals; the opposite occurred with females: castration induced an increase of these parameters. CRF animals showed increased cortical and glomerular fibronectin (FN) rates. Castration decreased glomerular and cortical FN rates in CRFM but not in females. In conclusion, proteinuria was higher in CRFM and probably led to glomerular and interstitial damage, as well as to FN accumulation, castration seems to protect against development of PTN, TID and FN accumulation in males. Castrated female rats presented mesangial expansion, with no changes in PTN, TID and FN rates. It seems that female sex hormones do not protect against renal disease progression, instead, we suggest that male sex hormones lead to acceleration of CRF.

Kappa-casein gene study with molecular markers in female buffaloes (Bubalus bubalis)

Caseins comprise make up about 80% of the total protein content of milk and present polymorphism with change in the amino acid sequence. Within this abundance of proteins, kappa-casein is noteworthy, since it has been associated with differences in milk yield, composition and processing. The objective of this study was to observe the existence of polymorphism in the kappa-casein gene in female buffaloes. For this purpose, blood samples from 115 female buffaloes, collected with vacutainer by needle punctionure of the jugular vein, were used. for genomic DNA extraction was done from blood samples. The PCR-RFLP and SSCP techniques demonstrated that the studied animals were monomorphic for the kappa-casein gene. Only allele B was observed in these animals, which was present in homozygosis. Therefore, it was not possible to quantify the gene action on milk yield and its constituents. The monomorphism observed in the population studied would allow the development of a method to identify mixtures of cow and buffalo milk in mozzarella cheese production, especially because, in cattle, the kappa-casein gene is polymorphic. Copyright by the Brazilian Society of Genetics.

Morphohistochemical characterization of the perivisceral fat body in royal and worker female castes in different ages of Atta sexdens rubropilosa ants (Hymenoptera, Formicidae)

The morphohistochemical study of the fat body in royal and worker castes of Atta sexdens rubropilosa revealed that this tissue is made up of trophocytes and oenocytes, trophocytes being the cells with cytoplasmic inclusions and irregular nuclei and the oenocytes cells with homogeneous cytoplasm and rounded nuclei. The trophocytes of queens presented many lipidic and proteic granules, while those of workers presented trophocytes with fine granulation in the cytoplasm constituted mainly by lipids and carbohydrates. The oenocytes from the worker caste of A. s. rubropilosa presented cytoplasm filled mainly with lipoproteic material.

Influence of endogenous and synthetic female sex hormones on human blood cells in vitro studied with comet assay

The comet assay has been conducted with numerous cell lines to assess in vitro genotoxicity. In order to use the comet assay as part of an in vitro test for evaluating genotoxicity, however, there are cell-specific factors that need to be better understood. In this present study we have evaluated some factors that may impact upon the DNA damage detected in whole blood (WB) cells and lymphocytes (ILs). Experiments were conducted comparing responses of both cells, and investigating the effects of the female hormonal cycle, and oral contraceptive (OC) use on DNA damage detection in the in vitro comet assay, at three sampling time. No significant differences were detected in the basal levels of DNA damage detected in ILs and WB cells from women OC users and non-users and from men. Basal DNA damage in ILs was unaffected by gender and stage of the menstrual cycle or the stage of the treatment schedule. Our results also indicated that the H2O2 induces DNA damage in human lymphocytes independently of gender, low-dose OC use and hormonal fluctuation. However, data showed that in 3rd sampling of menstrual cycle, lymphocytes were more resistant to H2O2-induced DNA damage than those from OC users and men. © 2007 Elsevier Ltd. All rights reserved.

Effects of atrazine on female Wistar rats: Morphological alterations in ovarian follicles and immunocytochemical labeling of 90 kDa heat shock protein

Fertility in female mammals may be affected by a variety of endocrine disrupters present in the environment. Herbicide atrazine is an example of endocrine disrupter employed in agriculture, which disrupts estrous cyclicity in rats. Aiming to characterize morphologically the effect of low and sublethal doses of atrazine on the ovaries of Wistar rats, in an effort to determine the possible intrafollicular target site through which this herbicide acts adult females were submitted to both subacute and subchronic treatments. Additionally, immunocytochemical labeling of 90 kDa heat shock protein (HSP90) was performed in order to evaluate the role played by this protein in the ovary, under stressed conditions induced by herbicide exposure. The results indicated that atrazine induced impaired folliculogenesis, increased follicular atresia and HSP90 depletion in female rats submitted to subacute treatment, while the subchronic treatment with low dose of atrazine could compromise the reproductive capacity reflected by the presence of multioocytic follicle and stress-inducible HSP90. © 2007 Elsevier Ltd. All rights reserved.