Behaviour and role of an intra-acrosomal antigenic molecule, acrin 3, during mouse fertilisation in vitro

In this study we examined the behaviour and role of an intra-acrosomal antigenic molecule, acrin 3, during mouse fertilisation in vitro by assessing the effect of its pertinent monoclonal antibody mMC101. Experiments were designed to assess the effect of mMC101 on sperm-zona pellucida binding, the acrosome reaction, zona pellucida penetration, sperm-egg fusion, and fertilisation in vitro. mMC101 did not affect sperm motility or primary and secondary binding to the zona pellucida, but significantly inhibited fertilisation of zona-pellucida-intact oocytes in a dose-dependent manner. In the presence of mMC101 at 100 microg/ml concentration in TYH medium, none of the oocytes developed to pronuclear stage by 5 h after co-incubation of the gametes, but the pronucleus formation rate recovered to some extent (45.3%) after 8 h, indicating a delay of early embryonic development. mMC101 also delayed and significantly suppressed zona pellucida penetration by sperm. Acrin 3 dispersed and did not remain on completely acrosome-reacted sperm. Although mMC101 did not influence the zona-pellucida-induced acrosome reaction, it significantly inhibited fertilisation when acrosome-reacted sperm in the presence of mMC101 inseminated zona-pellucida-free oocytes. However, fertilisation remained unaffected when acrosome-reacted sperm in the absence of mMC101 inseminated zona-pellucida-free oocytes even in its presence. Thus, acrin 3 appears to facilitate zona pellucida penetration and is also likely to be involved in sperm-oocyte fusion by modifying the sperm plasma membrane during the acrosome reaction.     

A ligand-induced extracellular cleavage regulates gamma-secretase-like proteolytic activation of Notch1

Gamma-secretase-like proteolysis at site 3 (S3), within the transmembrane domain, releases the Notch intracellular domain (NICD) and activates CSL-mediated Notch signaling. S3 processing occurs only in response to ligand binding; however, the molecular basis of this regulation is unknown. Here we demonstrate that ligand binding facilitates cleavage at a novel site (S2), within the extracellular juxtamembrane region, which serves to release ectodomain repression of NICD production. Cleavage at S2 generates a transient intermediate peptide termed NEXT (Notch extracellular truncation). NEXT accumulates when NICD production is blocked by point mutations or gamma-secretase inhibitors or by loss of presenilin 1, and inhibition of NEXT eliminates NICD production. Our data demonstrate that S2 cleavage is a ligand-regulated step in the proteolytic cascade leading to Notch activation.     

Circadian periodicity of urinary volume, creatinine and 5-hydroxyindole acetic acid excretion in healthy Indians

The circadian periodicity of urinary output, creatinine (Cr) and 5-hydroxyindole acetic acid (5-HIAA) excretion was studied under near-tropical conditions in 130 healthy volunteers (65 men and 65 women, 16-75 years of age) with a diurnal activity from about 06:30 to about 22:00 and nocturnal rest. These volunteers were divided into 4 groups, 16-30, 31-45, 46-60 and 61-75 years of age, comprising 20, 20, 15 and 10 participants of each gender, respectively. A marked circadian rhythm was recorded for urine volume, Cr and 5-HIAA excretion in healthy Indians of different ages. The acrophase tended to be delayed in the older age group. The relative amplitude decreased with advancing age, notably in women. Overall, men produced a larger urine volume as compared to women. Excretions of Cr and 5-HIAA in healthy Indian volunteers of different ages may be influenced by diet, societal relations, climate and/or geographic location. The contribution of such factors in metabolism and degradation warrants further study.     

The importance of homologous recombination in the generation of large deletions in hybrid plasmids in Amycolatopsis mediterranei

The whole nucleotide sequence of pT3.2I, the smallest plasmid of the acidophilic bacterium Thiobacillus T3.2, has been determined. pT3.2I is 15,390 bp long with a 53.7% GC content. Different regions can be defined in it: one 2569-bp putative insertion sequence similar to other insertion sequences of some Agrobacterium Ti plasmids; and a longer sequence, which occurs in two almost identical copies, differing only in a 1-bp deletion (6406 and 6405 bp). Several open reading frames and some smaller sequences were found in this duplicated region: ORFA and ORFG, encoding a putative polyol dehydrogenase and a putative RepA replication protein, respectively, an 83-bp sequence which could code for an antisense RNA, and a 36-bp region highly homologous to ori sequences of ColE2- and ColE3-related plasmids. Another putative gene, ORFH, is only present in the longer copy of this region (it is deleted in the short copy) and might encode a 90-amino-acid polypeptide which could act as a second replication protein, RepB. Based on sequence comparisons, pT3. 2I can be related to plasmids in the pColE2-CA42 incB incompatibility group.     

Insecticidal toxin from Bacillus thuringiensis is released from roots of transgenic Bt corn in vitro and in situ

The insecticidal toxin encoded by the cry1Ab gene from Bacillus thuringiensis was released in root exudates from transgenic Bt corn during 40 days of growth in soil amended to 0, 3, 6, 9, or 12% (v/v) with montmorillonite or kaolinite in a plant growth room and from plants grown to maturity in the field. The presence of the toxin in rhizosphere soil was determined by immunological and larvicidal assays. No toxin was detected in any soils from isogenic non-Bt corn or without plants. Persistence of the toxin was apparently the result of its binding on surface-active particles in the soils, which reduced the biodegradation of the toxin. The release of the toxin could enhance the control of insect pests or constitute a hazard to nontarget organisms, including the microbiota of soil, and increase the selection of toxin-resistant target insects.     

Short Communication: Carbon source-starvation-induced precipitation of copper by Pseudomonas putida strain S4

Pseudomonas putida strain S4, when starved of carbon source, precipitated Cu2+ in the medium. The precipitate, apart from containing copper, consisted of phosphate and hydroxide residues. While high acid phosphatase activity provided the necessary phosphates for Cu2+-precipitation, hydroxyl residues generated by metal efflux pathway may be used for metal hydroxide precipitation. This phenomenon could be exploited in the biorecovery of copper from different sources.     

Quantitative estimation of major histocompatibility complex antigens on live tumour cells

Quantitation of major histocompatibility complex (MHC) antigens on cells can accurately be done by using a flowcytometer. Since flowcytometer is not freely accessable an alternate, simple method for relative quantitation of MHC antigens has been devised. In this procedure, YAC lymphoma cells were first treated with a monoclonal anticlass I MHC antibody and then with a rabbit anti mouse Ig-antibody coupled to peroxidase, followed by colour development using a substrate of peroxidase enzyme. Various assay parameters have been optimized. The validity of the procedure was examined by assessing the enhanced MHC expression on YAC cells treated with a soluble rat spleen derived factor, by the new procedure as well as by the flowcytometer. Comparable results were obtained by using both techniques.     

Water transmission barrier properties of biodegradable films based on cellulosic whiskers and xylan

The reinforcement of natural biopolymers with cellulosic whiskers has been shown to be beneficial for physical strength properties including xylan films. This study examines the water transmission properties of xylan films reinforced with cellulosic whiskers prepared from kraft pulp hydrolyzed with sulfuric acid. Measurements of water transmission rate (WVTR) were accomplished by a modification of wet cup method described by ASTM E 96-95. The results showed that films prepared by xylan reinforced by 10% sulfonated whiskers exhibited a 74% reduction in specific water transmission properties with respect to xylan film and a 362% improvement with respect to xylan films reinforced with 10% softwood kraft fibers.     

Prevalence of Myopia and Its Risk Factors in Urban School Children in Delhi: The North India Myopia Study (NIM Study)

PurposeAssess prevalence of myopia and identify associated risk factors in urban school children.MethodsThis was a cross-sectional study screening children for sub-normal vision and refractive errors in Delhi. Vision was tested by trained health workers using ETDRS charts. Risk factor questionnaire was filled for children with vision <6/9.5, wearing spectacles and for a subset (10%) of randomly selected children with normal vision. All children with vision <6/9.5 underwent cycloplegic refraction. The prevalence of myopia <-0.5 diopters was assessed. Association of risk factors and prevalence of myopia was analyzed for children with myopia and randomly selected non myopic children and adjusted odds ratio values for all risk factors were estimated.ResultsA total number of 9884 children were screened with mean age of 11.6 + 2.2 years and 66.8% boys. Prevalence of myopia was 13.1% with only 320 children (24.7%) wearing appropriate spectacles. Mean myopic spherical error was -1.86 + 1.4 diopters. Prevalence of myopia was higher in private schools compared to government schools (p<0.001), in girls vs. boys (p = 0.004) and among older (> 11 years) children (p<0.001). There was a positive association of myopia with studying in private schools vs. government schools (p<0.001), positive family history (p< 0.001) and higher socio-economic status (p = 0.037). Positive association of presence of myopia was observed with children studying/reading > 5 hours per day (p < 0.001), watching television > 2 hours / day (p < 0.001) and with playing computer/video/mobile games (p < 0.001). An inverse association with outdoor activities/playing was observed with children playing > 2 hours in a day.ConclusionMyopia is a major health problem in Indian school children. It is important to identify modifiable risk factors associated with its development and try to develop cost effective intervention strategies.     

Awareness and Attitude towards Breastfeeding among Two Generations of Indian Women: A Comparative Study

IntroductionPresent study was aimed to analyze the impact of education, employment and financial independence in breastfeeding practices among Indian women.MethodologyPresent explorative questionnaire based survey included 256 women (128 pairs) in the final analysis. A pair means – a) pregnant lady (in her third trimester) representing younger generation and b) her mother/mother in law representing the elder generation.ResultsWe found that the overall awareness regarding ‘breast milk’ being the best food for baby was excellent (overall 97.3%; younger generation: 96.9%; elder generation: 97.7%). Overall knowledge regarding the correct technique (28.9% younger generation and 21.9% elder generation) and frequency of breastfeeding (20.3% of younger generation and 34.4% of elder generation) was very poor. Less than 60% (younger generation: 57.8%; elder generation: 58.6%) were aware that the only major contraindication for breastfeeding is a mother infected with human immunodeficiency virus (HIV). On comparing responses obtained from the two generations of women, difference was not statistically significant among most of the issues related to breastfeeding. With regards to the attitude, despite better awareness, only 94.5% women in younger generation and 89.1% women in elder generation were planning to give mother’s milk as the first feed to the newborn. Similarly, less than 75% of women were ready to breast-feed the newborn immediately after birth. This was contradictory to the fact that 86% of pregnant women were aware that the baby should be breast-fed within an hour of birth.ConclusionAwareness with regards to breastfeeding issues had not changed significantly with the educational progress of Indian women. Despite the good level of awareness in the society regarding breastfeeding, attitude to practice the same is lacking.