Age effect of broiler breeders on fertility and sperm penetration of the perivitelline layer of the ovum

The objective of this study was to determine the age effect of a broiler breeder flock on duration of fertility and number of spermatozoa penetrating the perivitelline layer overlying the germinal disc (SP/mm(2) GDIPVL). Moreover, in the second half of the flock's reproductive life, the effect of using ejaculates of young roosters (CA2) in artificial insemination (AI) on the above parameters of fertility was estimated. The commercial flock of broiler breeder hens (n = 100) was inseminated six times from 31 to 62 weeks of age. Additional inseminations, with ejaculates of roosters aged 31 and 36 weeks (CA2), were performed at 56 and 62 weeks of age. AI was performed during two consecutive days (D0 and D1) with an insemination dose of 125 x 10(6) spermatozoa/0.06 ml containing pooled ejaculates. The following parameters were studied: the effective and maximum duration of fertility (De and Dm), percent of fertility on different days after AI (FD10, FD15 and FD20), indices of duration of sperm penetration (DSP, SP < or = 3/GDIPVL), SP/mm(2) GDIPVL in eggs laid on successive days after insemination of hens at different age, and correlations between some fertility indices. Both for De and Dm, the highest values were noted after AI of the layers at 36 weeks of age (14.8 +/- 0.49 and 17.4 +/- 0.46 days, respectively), which were about 2 days longer than at 56 weeks. All fertility indices decreased gradually with age, starting from AI at peak egg production (31-36 weeks of age), while the use of ejaculates from CA2 did not help to increase them significantly. Correlation coefficients between SP/mm(2) GDIPVL and the other fertility indices were positive and highest for eggs laid on D3. It is concluded that high De values can be obtained from broiler breeders in adequate environmental and technological conditions of AI. It is suggested that the age-related decrease in fertility is more pronounced in females, in which the efficiency of sperm storage tubules decreases. The present fertility indices indicate the possibility of lengthening AI intervals, especially at peak egg production.     

Complex role of the FA proteins in providing genome stability

FA is a rare genetic disorder characterized by developmental abnormalities, bone marrow failure and cancer susceptibility. Cells that are derived from patients with FA display spontaneous chromosomal instability and hypersensitivity to DNA crosslinking agents that is used in FA clinical diagnostics. FA is genetically heterogeneous and caused by mutations in at least 11 distinct genes, FANCA, FANCA, B, C, D1, D2, E, F, G, I, J and L. FA proteins interact with various proteins involved in DNA damage response and cell cycle checkpoint regulation, such as: RAD51, BRCA1, BRCA2, ATM or NBS1. Moreover, BRCA2 that plays a crucial role in homologous recombination is one of FA proteins. Collectively, all these data indicate, that the FA pathway is involved in different molecular processes that prevent DNA and control genomic stability, although its precise role still remains undefined.     

Reversal of the sex difference in plasma leptin levels in obese children with impaired glucose tolerance

INTRODUCTION: Basal leptin level has been demonstrated to correlate positively with many indices of obesity, as well as insulin resistance. However, to date, little is known about regulation of leptin in obese children with incipient glucose metabolic disorders. OBJECTIVE: The aim of this study was to define the precise influence of the glucose tolerance status on plasma leptin in obese boys and girls separately. MATERIAL AND METHODS: 70 obese children with impaired glucose tolerance (IGT) and well-matched 70 normal glucose-tolerant (NGT) subjects were examined. Fasting and 2-h post glucose load plasma glucose and insulin levels as well as fasting leptin levels were determined, apart from anthropometric measurements. RESULTS: Leptin levels were significantly lower in girls with IGT compared to NGT girl (17.7+/-6.5 microg/L vs. 23.1+/-7.7 microg/L; p<.001). No such difference was observed in boys. In a multiple regression analysis adjusting for age and adiposity, in the female group plasma glucose and insulin levels 2-h after glucose load were the best predictors of fasting plasma leptin (r=-0.49, p<.005 and r=0.34, p<.05; respectively). In boys, plasma insulin level 2-h after glucose load was the independent determinant of leptin (r=0.36, p<.05). CONCLUSION: The differences between regulation of leptin synthesis in girls and boys with simple obesity were found. The stimulatory effect of insulin on leptin synthesis was greater in girls with normoglycemia than in girls with impaired glucose tolerance.     

Reversal of the sex difference in plasma leptin levels in obese children with impaired glucose tolerance

INTRODUCTION: Basal leptin level has been demonstrated to correlate positively with many indices of obesity, as well as insulin resistance. However, to date, little is known about regulation of leptin in obese children with incipient glucose metabolic disorders. OBJECTIVE: The aim of this study was to define the precise influence of the glucose tolerance status on plasma leptin in obese boys and girls separately. MATERIAL AND METHODS: 70 obese children with impaired glucose tolerance (IGT) and well-matched 70 normal glucose-tolerant (NGT) subjects were examined. Fasting and 2-h post glucose load plasma glucose and insulin levels as well as fasting leptin levels were determined, apart from anthropometric measurements. RESULTS: Leptin levels were significantly lower in girls with IGT compared to NGT girl (17.7+/-6.5 microg/L vs. 23.1+/-7.7 microg/L; p<.001). No such difference was observed in boys. In a multiple regression analysis adjusting for age and adiposity, in the female group plasma glucose and insulin levels 2-h after glucose load were the best predictors of fasting plasma leptin (r=-0.49, p<.005 and r=0.34, p<.05; respectively). In boys, plasma insulin level 2-h after glucose load was the independent determinant of leptin (r=0.36, p<.05). CONCLUSION: The differences between regulation of leptin synthesis in girls and boys with simple obesity were found. The stimulatory effect of insulin on leptin synthesis was greater in girls with normoglycemia than in girls with impaired glucose tolerance.     

Ionizing radiation-induced foci formation of mammalian Rad51 and Rad54 depends on the Rad51 paralogs, but not on Rad52

Homologous recombination is of major importance for the prevention of genomic instability during chromosome duplication and repair of DNA damage, especially double-strand breaks. Biochemical experiments have revealed that during the process of homologous recombination the RAD52 group proteins, including Rad51, Rad52 and Rad54, are involved in an essential step: formation of a joint molecule between the broken DNA and the intact repair template. Accessory proteins for this reaction include the Rad51 paralogs and BRCA2. The significance of homologous recombination for the cell is underscored by the evolutionary conservation of the Rad51, Rad52 and Rad54 proteins from yeast to humans. Upon treatment of cells with ionizing radiation, the RAD52 group proteins accumulate at the sites of DNA damage into so-called foci. For the yeast Saccharomyces cerevisiae, foci formation of Rad51 and Rad54 is abrogated in the absence of Rad52, while Rad51 foci formation does occur in the absence of the Rad51 paralog Rad55. By contrast, we show here that in mammalian cells, Rad52 is not required for foci formation of Rad51 and Rad54. Furthermore, radiation-induced foci formation of Rad51 and Rad54 is impaired in all Rad51 paralog and BRCA2 mutant cell lines tested, while Rad52 foci formation is not influenced by a mutation in any of these recombination proteins. Despite their evolutionary conservation and biochemical similarities, S. cerevisiae and mammalian Rad52 appear to differentially contribute to the DNA-damage response.     

Subfertile couple with t(4;22)(q23;q11.2)

A couple was referred for cytogenetic examination due to idiopathic miscarriages. The proband proved to be a carrier of chromosomal translocation and her partner's karyotype was found to be normal. The karyotype of the proband is 46,XX,t(4;22)(q23;q11.2) and can be regarded as a reason of fertility problems in the investigated couple. The risk of further miscarriages is high, but the risk of a progeny with abnormal karyotype is rather low, as the progeny would probably have lethal imbalances.     

Pulse radiolysis study of the interaction of retinoids with peroxyl radicals

Vitamin A (retinol) and its derivatives-retinal and retinoic acid-are known for their ability to inhibit lipid peroxidation. Antioxidant actions of retinoids have been attributed to chain-breaking by scavenging of peroxyl radicals. Based on chemical analysis of retinoic acid degradation products formed during microsomal lipid peroxidation, it was previously suggested that retinoids interact with peroxyl radicals forming free carbon-centered radical adducts. However, it can be argued that such a mode of antioxidant action of retinoids is not sufficient to fully explain their effectiveness at inhibiting lipid peroxidation, which in many systems is comparable to, or even exceeds, that of alpha-tocopherol. In order to elucidate the mechanism of interaction of retinoids with peroxyl radicals, (trichloromethyl)peroxyl radical was generated by pulse radiolysis, and its interactions with retinoids solubilized in Triton X-100 micelles were followed by kinetic absorption spectroscopy. All retinoids--retinol, retinal, and retinoic acid--interacted with the peroxyl radical, and at least two transient products were detected. One of these products, absorbing at 590 nm, was identified as retinoid cation radical. Therefore, we postulate that, apart from formation of radical adducts, retinoids may also scavenge peroxyl radicals by electron transfer.     

Effects of elastase and cathepsin G on the levels of membrane and soluble TNFalpha

Neutrophil elastase (NE) and cathepsin G (CG), the proteolytic enzymes localized in azurophil granules of neutrophils (PMN), are involved in PMN responses to various stimuli. When released at sites of inflammation, they participate in the degradation of numerous proteins involved in the regulation of the immune response. In this study, we employed ADAM17(-/-) fibroblasts stably transfected with cDNA of human pro-tumor necrosis factor alpha (proTNFalpha) (ADAM17(-/-)TNF(+)) to investigate the effects of NE and CG on shedding and degradation of TNFalpha. Both NE and CG were found to diminish the level of membrane TNFalpha (mTNFalpha) as measured by flow cytometry. This process was accompanied by the accumulation of biologically active soluble TNFalpha (sTNFalpha) in the culture medium, as determined by an increase in both the cytotoxic activity of TNFalpha and its ability to serve as a co-stimulator in the induction of inducible nitric oxide synthase (iNOS). However, in contrast to CG, NE at high concentrations was able to degrade sTNFalpha released from the cell surface. Using soluble recombinant human TNFalpha, we identified Val(93)-Ala(94) and Val(117)-Glu(118) as the NE cleavage sites within the sTNFalpha molecule. Taken together, the ability of NE and CG to modulate levels of membrane and soluble forms of TNFalpha may contribute to the proinflammatory activity of neutrophils.