Time dependent impact of reactive oxidants on seminal attributes, mitochondrial membrane potential, lipid peroxidation and capacitation-like changes of Karan-Fries bulls during cryopreservation.

BACKGROUND: Cryopreservation of semen is a valuable technique; however, it is also known to be detrimental to the structure of spermatozoa and fertility due to cryo-injury and subsequent generation of reactive oxidants. OBJECTIVE: To determine the time-dependent impact of reactive oxidants on seminal attributes, mitochondrial membrane potential (MMP), lipid peroxidation status (LPO) and early capacitation like changes. MATERIALS AND METHODS: Semen samples were collected by artificial vagina technique from six Karan-Fries (KF) bulls and subsequently examined at 0 h (before cryopreservation) and at 24 hours, 15 days and 2-months of storage for various seminal attributes, MMP, and early capacitation-like changes. Simultaneously, LPO (TBARS) was determined in fresh and post-thaw seminal plasma. RESULTS: A sharp decrease (P < 0.01) in semen quality was observed only after 24 h of cryopreservation except for viability and acrosomal integrity. Sperm viability and acrosome integrity reduced significantly up to 2 months of cryopreservation. The lipid peroxidation status was found to be lower in fresh seminal plasma (2.6 ±0.2 vs. 3.5 ± 0.3 units/mL) as compared to post-thaw. Furthermore, the active MMP of fresh semen showed a significant (P < 0.01) decrease after 24 hours (77.9 ± 0.4 vs. 54.5 ±0.3%) of cryopreservation, while there was a non-significant decrease in active MMP after 15 d and 2-months (53.7 ± 0.1 and 52.8 ± 0.2%). Moreover, significant (P. < 0.01) early capacitation-like changes were found in post-thaw spermatozoa (25.7 ± 0.1 vs. 9.1 ± 0.2%) as compared to fresh ejaculate. CONCLUSION: Spermatozoa incur the majority of damages during the early phase of cryopreservation, however the damage associated by different stressors cannot be neglected. doi.org/10.54680/fr22410110212.

Ready student one: Exploring the predictors of student learning in virtual reality.

Immersive virtual reality (VR) has enormous potential for education, but classroom resources are limited. Thus, it is important to identify whether and when VR provides sufficient advantages over other modes of learning to justify its deployment. In a between-subjects experiment, we compared three methods of teaching Moon phases (a hands-on activity, VR, and a desktop simulation) and measured student improvement on existing learning and attitudinal measures. While a substantial majority of students preferred the VR experience, we found no significant differences in learning between conditions. However, we found differences between conditions based on gender, which was highly correlated with experience with video games. These differences may indicate certain groups have an advantage in the VR setting.

Autosomal Dominant Polycystic Kidney Disease: Presence of Hypomorphic Alleles in PKD1 Gene.

Autosomal dominant polycystic kidney disease is characterized by multiple cysts in both kidneys manifesting in adult life. In general, the disorder is caused by a pathogenic variant in one allele of PKD1 or PKD2 genes, while the other allele is normal. Pathogenic variants in both the alleles are rare and have variable phenotypes, from lethal or perinatal presentation to a mild form in later adulthood, depending on the type of variant. Here, we describe a proband with two variants (p.Thr1773Ile and p.Ala1871Thr in trans) in PKD1 gene, who presented with disease at age 24 years. Both the parents and one brother had a variant in one allele, the other being wild type only and had normal ultrasound findings. Segregation studies suggest that both the variants may act as "hypomorphic" or "incompletely penetrant" alleles and acting together resulted in haploinsufficiency of protein PC1 in renal cells, leading to cystogenesis in the proband. The consequences of the presence of two hypomorphic variants have been poorly documented in literature. We reviewed the few published cases having two hypomorphic variants and the data conform to the conclusions that we reached by study of the family described. It is emphasized that to resolve the significance of suspected hypomorphic variants, segregation studies in the parents and siblings are essential.

Prevalence of CYP2C8 polymorphisms in a North Indian population.

CYP2C8 is an important member of the cytochrome P450 family of enzymes; it affects the activity of various drugs used in routine clinical practice, including amiodarone, chloroquine, amodiaquine, and repaglinide, as well as endogenous compounds, such as arachidonic acid and retonic acid. It is also the main enzyme involved in the metabolism of the widely used anticancer drug Paclitaxel, which has a very narrow therapeutic index. There is evidence that single nucleotide polymorphisms in the CYP2C8 gene influence the adverse reactions and/or the efficacy of drugs metabolized by this enzyme. We examined the allele and genotype frequencies of widely studied functional polymorphisms of the CYP2C8 gene in a North Indian population. We assayed the genomic DNA of at least 251 healthy unrelated North Indians for CYP2C8*2, CYP2C8*3 (G416A, A1196G), and CYP2C8*4 genetic polymorphisms by RFLP technique. These results were compared to information on other populations. The allelic frequencies of CYP2C8*2, CYP2C8*3, and CYP2C8*4 were found to be 3, 4, and 4% respectively. The two CYP2C8*3 polymorphisms (G416A and A1196G) were found to be completely linked to each other. Allele frequencies of CYP2C8 genetic variants in northern Indians were found to have a distinct pattern that differs from that of southern Indian and other global populations. This is the first report from North India on CYP2C8 polymorphisms. Ethnic differences with respect to polymorphisms are the molecular basis of interethnic variability in pharmacokinetics. Our study may help in rational use of drugs that are substrates for CYP2C8 in this population.

Effect of pre-partum supplementation of vitamin E to Murrah buffaloes on immune functions and viability of calves.

This study was undertaken in buffalo neonates born to vitamin E (dl-alpha-tocopherol acetate)-supplemented and non-supplemented Murrah buffaloes. Calves from vitamin E-supplemented buffaloes (n = 10; vitamin E -supplemented calves [VeC]) and non-supplemented buffaloes (n = 10; control calves [CC]) constituted the treatment and control groups respectively. Two colostrum samples were taken at the first post-partum milking and again after 12 h from dams for IgG estimation. Sampling of blood was performed on days 0 (before colostrum feeding), 1, 3, 7, 14, 21, 28, 42, 56, 70, 84, 98, 112 and 126 post-birth and analysed for apparent efficiency of absorption (%) of IgG and various immune parameters. Colostral IgG level was significantly higher (p < 0.05) in vitamin E-supplemented buffaloes. The calves in both groups were born hypogammaglobulinemic with IgG level <5 g/l. However, first colostrum feeding resulted in significantly elevated IgG levels (>10 g/l) in calves of both groups at 24 h, which remained high afterwards. Apparent efficiency of absorption (%) of IgG at 24 h was significantly higher (p < 0.05) in VeC than in CC. Plasma Nitric Oxide (NO) levels were significantly elevated in the calves of either group at birth, which declined significantly (p < 0.01) afterwards. Vitamin E feeding to dams had no added effect on NO levels in experimental calves. Total leucocyte counts did not differ significantly between the two groups. However, lymphocyte and neutrophil counts changed significantly between groups (p < 0.01) and days (p < 0.01), with lymphocytes increasing and neutrophils declining with age. This study revealed that the calves were immunologically immature at birth. Ante-partum supplementation of vitamin E did not influence plasma NO or IgG but had a significant effect on colostral IgG (p < 0.05). It also improved the apparent efficiency of absorption (%) of IgG at 24 h in VeC as compared to CC.

Effects of FSH and LH on steroid production by buffalo (Bubalus bubalis) granulosa cells cultured in vitro under serum-free conditions.

The objective of this study was to examine the effects of FSH and LH on oestradiol-17ß and progesterone production by buffalo granulosa cells cultured under serum-free conditions. Granulosa cells (3 × 10(5) ) from small (≤ 5 mm diameter) follicles were cultured for up to 4 days in 48-well plates coated with 3.3 µg/cm(2) fibronectin in Dulbecco's modified Eagle's medium (DMEM) : nutrient mixture F-12 Ham (1 : 1 ratio) supplemented with 10(-7) m androstenedione, 5 µg/ml human apo-transferrin and 0.1% bovine serum albumin, in the presence or absence of FSH or LH (0, 1, 2, 4, 8, 16, 32 or 64 ng/ml each). Basal oestradiol-17ß production by granulosa cells from small follicles reduced (p < 0.01) from days 1 to 2 of culture and became undetectable by day 3 and basal progesterone production increased (p < 0.05) from day 1 through day 4 of the culture. Although there was no effect of FSH on day 1 of the culture, FSH at 2, 4, 8 and 16 ng/ml increased (p < 0.05) oestradiol-17ß production by granulosa cells from small follicles on day 2. Progesterone secretion was increased (p < 0.05) by all doses of FSH on all days of culture. All doses of LH had no effect on oestradiol-17ß or progesterone production by granulosa cells from small follicles on any day of the culture. The results of this study demonstrate a serum-free culture system for buffalo granulosa cells and stimulatory effect of FSH but not LH on steroid hormone production by buffalo granulosa cells under these conditions.

Telomeres, histone code, and DNA damage response.

Genomic stability is maintained by telomeres, the end terminal structures that protect chromosomes from fusion or degradation. Shortening or loss of telomeric repeats or altered telomere chromatin structure is correlated with telomere dysfunction such as chromosome end-to-end associations that could lead to genomic instability and gene amplification. The structure at the end of telomeres is such that its DNA differs from DNA double strand breaks (DSBs) to avoid nonhomologous end-joining (NHEJ), which is accomplished by forming a unique higher order nucleoprotein structure. Telomeres are attached to the nuclear matrix and have a unique chromatin structure. Whether this special structure is maintained by specific chromatin changes is yet to be thoroughly investigated. Chromatin modifications implicated in transcriptional regulation are thought to be the result of a code on the histone proteins (histone code). This code, involving phosphorylation, acetylation, methylation, ubiquitylation, and sumoylation of histones, is believed to regulate chromatin accessibility either by disrupting chromatin contacts or by recruiting non-histone proteins to chromatin. The histone code in which distinct histone tail-protein interactions promote engagement may be the deciding factor for choosing specific DSB repair pathways. Recent evidence suggests that such mechanisms are involved in DNA damage detection and repair. Altered telomere chromatin structure has been linked to defective DNA damage response (DDR), and eukaryotic cells have evolved DDR mechanisms utilizing proficient DNA repair and cell cycle checkpoints in order to maintain genomic stability. Recent studies suggest that chromatin modifying factors play a critical role in the maintenance of genomic stability. This review will summarize the role of DNA damage repair proteins specifically ataxia-telangiectasia mutated (ATM) and its effectors and the telomere complex in maintaining genome stability.