Characterization study of Holoptelea integrifolia tree bark fibres reinforced epoxy composites

This study characterised the composite plate fabricated by epoxy matrix reinforced with alkaline-treated Holoptelea integrifolia tree bark fibre. Tensile and flexural test results clearly show that the mechanical characteristics of pure resin improve in direct proportion to the fibre up to 40%. However, impact test results show that 30% fibre mass ratio composite showed higher mechanical properties. The H. integrifolia fibre composites (HIFC) specimens were also characterised by using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDAX) and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) analysis. FESEM results show that the bonding between fibre and matrix was excellent. EDAX reveals the elemental proportion of HIFC. O-H, C- H, C-O-C, moisture content and aromatic structure are evident by FTIR spectroscopy. Thermal analysis reveals that the composites degrade rapidly when exposed above 210 °C.

Effect of trans-cinnamaldehyde nanoemulsion wash on chicken embryo development in fertilized eggs

Cleanliness of eggs is critical in successful hatching egg operations. The objective of this study was to investigate the effect of trans-cinnamaldehyde nanoemulsion (TCNE) wash treatments, as a sanitation strategy, on embryonic development in fertilized eggs. Trans-cinnamaldehyde is a generally recognized as safe status phytochemical obtained from cinnamon bark. TCNE were prepared with emulsifiers Tween 80 (Tw.80) or gum Arabic and lecithin (GAL) by sonication. Day-old fertilized eggs were subjected to TCNE wash treatments at 34°C for 5 min, followed by 18 d of incubation at 37.7°C. Washing of fertilized eggs with TCNE-Tw.80 or GAL at 0.48% concentration did not significantly alter the egg weight at d 18 of incubation, as compared to baseline and control (P > 0.05). The egg weight loss (calculated as percentage) did not differ significantly between eggs subjected to nanoemulsion wash treatments and control eggs (P > 0.05). In case of embryo fertility and mortality, for baseline and control, ∼ 95% fertility rate was achieved, with combined early and midterm mortality at 16%. Likewise, TCNE-Tw.80 or TCNE-GAL resulted in 95% fertility (P > 0.05), with 11% and 17% combined early and midterm mortality, respectively. Furthermore, TCNE wash treatments did not differ significantly in yolk sac and embryo weight (as compared to control) and did not affect the length of the d 18 embryo (P > 0.05). Moreover, TCNE wash treatments did not alter tibia weight and length (P > 0.05). Results suggest that TCNE could potentially be used as a natural antimicrobial for fertilized egg sanitation. Further studies in industry settings are warranted.

Trans-cinnamaldehyde nanoemulsion wash inactivates Salmonella Enteritidis on shelled eggs without affecting egg color

Salmonella Enteritidis is a major foodborne pathogen that causes enteric illnesses in humans, primarily through the consumption of contaminated poultry meat and eggs. Despite implementation of traditional disinfection approaches to reduce S. Enteritidis contamination, egg-borne outbreaks continue to occur, raising public health concerns and adversely affecting the popularity and profitability for the poultry industry. Generally Recognized as Safe (GRAS) status phytochemicals such as Trans-cinnamaldehyde (TC) have previously shown to exhibit anti-Salmonella efficacy, however, the low solubility of TC is a major hurdle in its adoption as an egg wash treatment. Therefore, the present study investigated the efficacy of Trans-cinnamaldehyde nanoemulsions (TCNE) prepared with emulsifiers Tween 80 (Tw.80) or Gum Arabic and lecithin (GAL) as dip treatments, at 34°C, for reducing S. Enteritidis on shelled eggs in presence or absence of 5% chicken litter. In addition, the efficacy of TCNE dip treatments in reducing trans-shell migration of S. Enteritidis across shell barrier was investigated. The effect of wash treatments on shell color were evaluated on d 0, 1, 7, and 14 of refrigerated storage. TCNE-Tw.80 or GAL treatments (0.06, 0.12, 0.24, 0.48%) were effective in inactivating S. Enteritidis by at least 2 to 2.5 log cfu/egg as early as 1 min of washing time (P < 0.05). In presence of organic matter, nanoemulsions (0.48%) reduced S. Enteritidis counts by ∼ 2 to 2.5 log cfu/egg as early as 1 min, (P < 0.05). Nanoemulsion wash also inhibited trans-shell migration of S. Enteritidis, as compared to control (P < 0.05). The nanoemulsion wash treatments did not affect shell color (P > 0.05). Results suggest that TCNE could potentially be used as an antimicrobial wash to reduce S. Enteritidis on shelled eggs, although further studies investigating the effect of TCNE wash treatments on organoleptic properties of eggs are necessary.

Inclusion of dietary β-mannanase improves performance and ileal digestibility and reduces ileal digesta viscosity of broilers fed corn-soybean meal based diet

This study was aimed to evaluate the influence of dietary β-mannanase inclusion on growth performance, apparent ileal digestibility, digesta viscosity, blood metabolites and excreta noxious gas emissions in broilers fed corn-soybean meal based diet. A total of 600 conventional healthy 1-d-old ROSS 308 broilers with body weight 45 ± 0.50 g (mean ± SD) were randomly assigned to 4 dietary treatments with 10 replicates cages, with 15 broilers in each and fed basal diet supplemented to corn-SBM based diets with 0, 2400, 4800, and 7200 MNU β-mannanase/kg for 35 d feeding trial period. Significant results were observed on improved average daily gain and reduced feed conversion ratio during trial period and also reduced ileal digesta viscosity and improved apparent ileal digestibility of dry matter, nitrogen and energy. However, no significant effects were found on blood urea nitrogen and creatinine, excreta noxious gas emissions. In conclusion, the inclusion of dietary β-mannanase had potential to improve daily gain and feed efficiency and apparent ileal digestibility while decreasing digesta viscosity of broiler.

Dopamine agonist signalling in the hypothalamus of female rats is independent of calcium-dependent kinases

We have previously demonstrated that dopamine agonist, SKF38396 (SKF), can substitute for progesterone in the facilitation of female reproductive behaviour in oestradiol benzoate-primed female rats and mice. We also reported that both progesterone- and SKF-initiated signalling were mediated by the cAMP-dependent protein kinase A signal transduction cascade. As the rapid effects of progesterone are also mediated by calcium-dependent kinases, calcium- and calmodulin-dependent kinase (CaMKII) and protein kinase (PKC), we sought to determine whether SKF-initiated signalling also recruited calcium as a second messenger. We measured the changes in the activation of CaMKII and PKC in the ventromedial nucleus (VMN) of the hypothalamus and preoptic area (POA) of the rat brain, which are the two regions implicated in the regulation of female reproductive behaviour in rodents. We measured the basal activities representing the activation of the kinases by in vivo treatments, as well as the total kinase activities assayed in the presence of exogenous cofactors in vitro. We report that, in contrast to progesterone-initiated signalling, there was no recruitment of calcium by SKF in the hypothalamus, as shown by the absence of changes in CaMKII activities in the VMN and POA. Furthermore, SKF-treatment resulted in a rapid increase in calcium-independent basal PKC activity in the VMN but not the POA. These rapid changes were not the result of changes in PKC protein levels or phosphorylation status. These data indicate that progesterone- and SKF-recruit distinct signalling molecules within the same regions of the brain to activate region-specific signal transduction pathways.

Managing the 2-week wait for breast patients

INTRODUCTION

Published data suggest that the 2-week wait system and triple assessment at one fast-track clinic visit is an out-dated method of capturing disease from a referral population. These studies report up to 32% of breast cancer coming from routine referrals. It has been recommended, therefore, that all breast referrals should be seen within 2 weeks. The sheer volume of referrals are likely to prevent this target being achieved. The aim of this study was to analyse the performance of our fast-track system.

PATIENTS AND METHODS

The Birmingham Heartlands and Solihull fast-track clinics were set up in 1999 with a prospective audit system. The data from this audit were retrospectively analysed and cross-referenced with the cancer data base to determine the referral origin of breast cancers from November 1999 to February 2005.

RESULTS

A total of 14,303 (fast-track, n = 6678; routine referral, n = 7625) patients were seen over a 5-year period. Overall, 1095 cancers (91.8% of the total) came from the fast-track clinics which had a pick-up rate of 16.4% compared with 98 cancers (8.2% of the total) and a pick-up rate of 1.3% for routine referrals (P < 0.001). The appropriateness of fast-track referral was also analysed which showed that 14.4% of cancers were detected if the referral criteria were met compared to 0.55% if they were inappropriate (P < 0.001).

CONCLUSIONS

The traditional fast-track, triple assessment breast clinic is an efficient and well-structured way of diagnosing disease. We recommend that the two system referral pattern should continue.

Risk factors for intrapair birth weight discordance in twins

OBJECTIVES

To determine the risk factors for birth weight discordance in twins.

METHODS

We used the United States (1995-97) Matched Multiple Birth File (n = 294 568) to assess the association between birth weight discordance and maternal sociodemographic, pregnancy and infant characteristics.

RESULTS

Eighty-four per cent of the twins were 0-19% discordant, 11.1% were 20-29% discordant, 3.4% were 30-39% discordant, and 1.8% were > or = 2 40% discordant. The risk factors for birth weight discordance for same-sex twins were eclampsia (odds ratio (OR) 1.39,95% confidence interval (CI) 1.20, 1.61), pre-eclampsia (OR 1.31, 95% CI 1.24, 1.38), pre-existing hypertension (OR 1.32, 95% CI 1.12, 1.56), diabetes (OR 1.13, 95% CI 1.04, 1.24) and certain congenital anomalies. For opposite-sex twins, the risk factors for birth weight discordance were pre-eclampsia (OR 1.17, 95% CI 1.09, 1.27), pre-existing hypertension (OR 1.59,95% CI 1.32, 1.91), and certain congenital anomalies. Also, smoking and increased maternal age were associated with birth weight discordance in both same-sex and opposite-sex twins.

CONCLUSIONS

Maternal hypertensive disorders, smoking and delayed childbearing were associated with intrapair birth weight discordance. The mechanisms of these associations deserve further investigation.

Binding of Gal4p and bicoid to nucleosomal sites in yeast in the absence of replication

The yeast transcriptional activator Gal4p can bind to sites in nucleosomal DNA in vivo which it is unable to access in vitro. One event which could allow proteins to bind to otherwise inaccessible sites in chromatin in living cells is DNA replication. To determine whether replication is required for Gal4p to bind to nucleosomal sites in yeast, we have used previously characterized chromatin reporters in which Gal4p binding sites are incorporated into nucleosomes. We find that Gal4p is able to perturb nucleosome positioning via nucleosomal binding sites in yeast arrested either in G1, with alpha-factor, or in G2/M, with nocodazole. Similar results were obtained whether Gal4p synthesis was induced from the endogenous promoter by growth in galactose medium or by an artificial, hormone-inducible system. We also examined binding of the Drosophila transcriptional activator Bicoid, which belongs to the homeodomain class of transcription factors. We show that Bicoid, like Gal4p, can bind to nucleosomal sites in SWI+ and swi1Delta yeast and in the absence of replication. Our results indicate that some feature of the intracellular environment other than DNA replication or the SWI-SNF complex permits factor access to nucleosomal sites.

DNA strand breaking by the hydroxyl radical is governed by the accessible surface areas of the hydrogen atoms of the DNA backbone

Despite extensive study, there is little experimental information available as to which of the deoxyribose hydrogen atoms of duplex DNA reacts most with the hydroxyl radical. To investigate this question, we prepared a set of double-stranded DNA molecules in which deuterium had been incorporated specifically at each position in the deoxyribose of one of the four nucleotides. We then measured deuterium kinetic isotope effects on the rate of cleavage of DNA by the hydroxyl radical. These experiments demonstrate that the hydroxyl radical reacts with the various hydrogen atoms of the deoxyribose in the order 5' H > 4' H > 3' H approximately 2' H approximately 1' H. This order of reactivity parallels the exposure to solvent of the deoxyribose hydrogens. Our work therefore reveals the structural basis of the reaction of the hydroxyl radical with DNA. These results also provide information on the mechanism of DNA damage caused by ionizing radiation as well as atomic-level detail for the interpretation of hydroxyl radical footprints of DNA-protein complexes and chemical probe experiments on the structure of RNA and DNA in solution.

Ultraviolet radiation-induced ubiquitination and proteasomal degradation of the large subunit of RNA polymerase II. Implications for transcription-coupled DNA repair

We have shown previously that UV radiation and other DNA-damaging agents induce the ubiquitination of a portion of the RNA polymerase II large subunit (Pol II LS). In the present study UV irradiation of repair-competent fibroblasts induced a transient reduction of the Pol II LS level; new protein synthesis restored Pol II LS to the base-line level within 16-24 h. In repair-deficient xeroderma pigmentosum cells, UV radiation-induced ubiquitination of Pol II LS was followed by a sustained reduction of Pol II LS level. In both normal and xeroderma pigmentosum cells, the ubiquitinated Pol II LS had a hyperphosphorylated COOH-terminal domain (CTD), which is characteristic of elongating Pol II. The portion of Pol II LS whose steady-state level diminished most quickly had a relatively hypophosphorylated CTD. The ubiquitinated residues did not map to the CTD. Importantly, UV-induced reduction of Pol II LS level in repair-competent or -deficient cells was inhibited by the proteasome inhibitors lactacystin or MG132. These data demonstrate that UV-induced ubiquitination of Pol II LS is followed by its degradation in the proteasome. These results suggest, contrary to a current model of transcription-coupled DNA repair, that elongating Pol II complexes which arrest at intragenic DNA lesions may be aborted rather than resuming elongation after repair takes place.

Approaches to the study of Rox1 repression of the hypoxic genes in the yeast Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae is a facultative aerobe that responds to changes in oxygen tension by changing patterns of gene expression. One set of genes that responds to this environmental cue is the hypoxic genes. Oxygen levels are sensed by changes in heme biosynthesis, which controls the transcription of the ROX1 gene, encoding a protein that binds to the regulatory region of each hypoxic gene to repress transcription. Several experimental molecular and genetic approaches are described here to study Rox1 repression. Derepression of the hypoxic genes is rapid, and one model for such a response requires that Rox1 have a short half-life. This was demonstrated to be the case by immunoblotting using a c-myc epitope-tagged protein. Rox1 repression is mediated through the general repressors Ssn6 and Tup1. To explore possible interactions among these proteins, all three were expressed and partially purified using a baculovirus expression system and histidine-tagged proteins. The effect of Ssn6 and Tup1 on the formation of Rox1-DNA complexes was explored using these purified proteins by both electrophoretic mobility shift and DNase I protection assays. We found that Rox1 DNA-binding activity decayed rapidly and that Ssn6 could stabilize and restore lost activity. Finally, genetic selections are described for the isolation of loss-of-function mutations in Rox1. Also, schemes are proposed for the reversion of such mutations. These selections have been extended to genetic analyses of the TUP1 and SSN6 genes.

Senescence mutants of Saccharomyces cerevisiae with a defect in telomere replication identify three additional EST genes

The primary determinant for telomere replication is the enzyme telomerase, responsible for elongating the G-rich strand of the telomere. The only component of this enzyme that has been identified in Saccharomyces cerevisiae is the TLC1 gene, encoding the telomerase RNA subunit. However, a yeast strain defective for the EST1 gene exhibits the same phenotypes (progressively shorter telomeres and a senescence phenotype) as a strain deleted for TLC1, suggesting that EST1 encodes either a component of telomerase or some other factor essential for telomerase function. We designed a multitiered screen that led to the isolation of 22 mutants that display the same phenotypes as est1 and tlc1 mutant strains. These mutations mapped to four complementation groups: the previously identified EST1 gene and three additional genes, called EST2, EST3 and EST4. Cloning of the EST2 gene demonstrated that it encodes a large, extremely basic novel protein with no motifs that provide clues as to function. Epistasis analysis indicated that the four EST genes function in the same pathway for telomere replication as defined by the TLC1 gene, suggesting that the EST genes encode either components of telomerase or factors that positively regulate telomerase activity.

Multiple elements and auto-repression regulate Rox1, a repressor of hypoxic genes in Saccharomyces cerevisiae

The ROX1 gene encodes a heme-induced repressor of hypoxic genes in yeast. Using RNA blot analysis and a ROX1/lacZ fusion construct that included the ROX1 upstream region and only the first codon, we discovered that Rox1 represses its own expression. Gel-retardation experiments indicated that Rox1 was capable of binding to its own upstream region. Overexpression of Rox1 from the inducible GAL1 promoter was found to be inhibitory to cell growth. Also, we found that, as reported previously, Hap1 is partially responsible for heme-induction of ROX1, but, in addition, it also may play a role in ROX1 repression in the absence of heme. There is a second repressor of anaerobic ROX1 expression that requires the general repressor Tup1/Ssn6 for its function.

The Rox1 repressor of the Saccharomyces cerevisiae hypoxic genes is a specific DNA-binding protein with a high-mobility-group motif

The ROX1 gene encodes a repressor of the hypoxic functions of the yeast Saccharomyces cerevisiae. The DNA sequence of the gene was determined and found to encode a protein of 368 amino acids. The amino-terminal third of the protein contains a high-mobility-group motif characteristic of DNA-binding proteins. To determine whether the Rox1 repressor bound DNA, the gene was expressed in Escherichia coli cells as a fusion to the maltose-binding protein and this fusion was partially purified by amylose affinity chromatography. By using a gel retardation assay, both the fusion protein and Rox1 itself were found to bind specifically to a synthetic 32-bp DNA containing the hypoxic consensus sequence. We assessed the role of the general repressor Ssn6 in ANB1 repression. An ANB1-lacZ fusion was expressed constitutively in an ssn6 deletion strain, and deletion of the Rox1 binding sites in the ANB1 upstream region did not increase the level of derepression, suggesting that Ssn6 exerts its effect through Rox1. Finally, ROX1 was mapped to yeast chromosome XVI, near the ARO7-OSM2 locus.

Effect of yoga on aerobic and anaerobic power of muscles

Aerobic Power (VO2 max) and anaerobic power were estimated in medical students before and after six weeks of yogic training. A significant increase in aerobic power and a significant decrease in anaerobic power was observed. This may be due to conversion of some of the Fast Twitch (F.T.) muscle fibres into Slow Twitch fibres (S.T.) during yogic training.