Seeking signatures of reinforcement at the genetic level: a hitchhiking mapping and candidate gene approach in the house mouse

Reinforcement is the process by which prezygotic isolation is strengthened as a response to selection against hybridization. Most empirical support for reinforcement comes from the observation of its possible phenotypic signature: an accentuated degree of prezygotic isolation in the hybrid zone as compared to allopatry. Here, we implemented a novel approach to this question by seeking for the signature of reinforcement at the genetic level. In the house mouse, selection against hybrids and enhanced olfactory‐based assortative mate preferences are observed in a hybrid zone between the two European subspecies Mus musculus musculus and M. m. domesticus, suggesting a possible recent reinforcement event. To test for the genetic signature of reinforcing selection and identify genes involved in sexual isolation, we adopted a hitchhiking mapping approach targeting genomic regions containing candidate genes for assortative mating in mice. We densely scanned these genomic regions in hybrid zone and allopatric samples using a large number of fast evolving microsatellite loci that allow the detection of recent selection events. We found a handful of loci showing the expected pattern of significant reduction in variability in populations close to the hybrid zone, showing assortative odour preference in mate choice experiments as compared to populations further away and displaying no such preference. These loci lie close to genes that we pinpoint as testable candidates for further investigation.     

Disclosing the origin and diversity of Omani cattle

Among all livestock species, cattle have a prominent status as they have contributed greatly to the economy, nutrition and culture from the beginning of farming societies until the present time. The origins and diversity of local cattle breeds have been widely assessed. However, there are still some regions for which very little of their local genetic resources is known. The present work aimed to estimate the genetic diversity and the origins of Omani cattle. Located in the south‐eastern corner of the Arabian Peninsula, close to the Near East, East Africa and the Indian subcontinent, the Sultanate of Oman occupies a key position, which may enable understanding cattle dispersal around the Indian Ocean. To disclose the origin of this cattle population, we used a set of 11 polymorphic microsatellites and 113 samples representing the European, African and Indian ancestry to compare with cattle from Oman. This study found a very heterogenic population with a markedly Bos indicus ancestry and with some degree of admixture with Bos taurus of African and Near East origin.     

Haemolytic and phospholipase A activities of the tentacle extract of Catostylus mosaicus

An extract prepared from the tentacle of Catostylus mosaicus was shown to lyse erythrocytes from rat, rabbit and human to a different extent; those from the rat being most susceptible followed by those from rabbit and human. The haemolytic activity was dependent on the concentration of crude extract protein exhibiting a sigmoidal curve. Only 60% of the haemolytic activity was retained after treament with heat and proteolytic enzyme. The extract was devoid of hydrolytic enzymes normally present in venoms except for phospholipase A activity, which resulted in the hydrolysis of membrane phospholipids with concomittant appearance of their lyso-derivatives.     

Ameliorative effect of resveratrol against cymoxanil-mancozeb induced toxicity in rats

This study was conducted to evaluate the cymoxanil-mancozeb (CM) toxicity and investigate the ameliorative effect of resveratrol (Res) against cymoxanil-mancozeb toxicity. Forty rats were divided into four groups; the first group was used as a control group, the second group was exposed to Res only at a dose of 20 mg/kg body weight for 4 weeks, and the third group was administered CM only at a dose of 799 mg/kg body weight for 4 weeks, The fourth group was co-treated with Res+CM for 4 weeks. Blood samples were analyzed for hematological and biochemical parameters. The comet assay was done on liver and blood specimens and histopathological examinations of the liver and intestine. The results demonstrated that CM exposure caused a significant increase in WBCs, lymphocytes, granulocytes, monocytes ALT, AST, ALP, and GGT, and total cholesterol and triglycerides levels accompanied by a decrease in HGB, HCT, RBCs and MCV, MCH, MCHC, HDL and glucose levels with no significant DNA damage in liver and blood. CM mixture induced severe pathological changes in small intestine and liver. Co-treatment of Res with CM improved hematological picture, lipid and glucose profiles also liver enzymes and decreased changes in the architecture of the liver and intestine.     

Optimization of β-mannanase production by Bacillus subtilis US191 using economical agricultural substrates

The Bacillus subtilis US191 strain producing highly thermostable β-mannanase was previously selected as potential probiotic candidate for application as feed supplement in poultry industry. Initially, the level of extracellular β-mannanase production by this strain was 1.48 U ml⁻¹. To improve this enzyme titer, the present study was undertaken to optimize the fermentation conditions through experimental designs and valorization of agro-industrial byproducts. Using the Plackett–Burman design, in submerged fermentation, a set of 14 culture variables was evaluated in terms of their effects on β-mannanase production. Locust bean gum (LBG), soymeal, temperature, and inoculum size were subsequently optimized by response surface methodology using Box–Behnken design. Under optimized conditions (1 g L⁻¹ LBG, 8 g L⁻¹ soymeal, temperature of 30°C and inoculum size of 10¹⁰ CFU ml⁻¹), a 2.59-fold enhancement in β-mannanase titer was achieved. Next, to decrease the enzyme production cost, the effect of partial substitution of LBG (1 g L⁻¹) by agro-industrial byproducts was investigated, and a Taguchi design was applied. This allowed the attaining of a β-mannanase production level of 8.75 U ml⁻¹ in presence of 0.25 g L⁻¹ LBG, 5 g L⁻¹ of coffee residue powder, 5 g L⁻¹ of date seeds powder, and 5 g L⁻¹ of prickly pear seeds powder as mannans sources. Overall, a 5.91-fold improvement in β-mannanase production by B. subtilis US191 was achieved.     

Klinefelter's syndrome, mosaic 46,XX/46,XY/47,XXY/48,XXXY/48,XXYY: a case report

A 35-year-old male was investigated for primary infertility. Clinical examination showed an intelligent man with normal facial appearance and moustache and small firm testes. Testicular histopathology revealed marked atrophy of the testes with no spermatogenesis and absence of germ cells. Hormonal profile showed elevated levels of FSH,LH and low levels of testosterone. Chromosome analysis from whole blood culture showed cells with 46,XX/46,XY/47,XXY/48,XXXY/48,XXYY mosaicism. The predominant cell line was 47,XXY (87.86%). 46,XY/47,XXY mosaicism is not uncommon. However, mosaicism of multiple sex chromosome aneuploidy is rarely observed. This is the first report of mosaicism in Klinefelter's syndrome variant with five cell lines.     

Value of mangroves in coastal protection

Nearly 30% of the coastline of Malaysia is undergoing erosion. Many of these areas are coastal mudflats, fringed by mangroves. Behind the mangroves there are usually agricultural areas that are protected by bunds from tidal inundation. These bunds are constructed by the Department of Irrigation and Drainage and it is the policy of the department to maintain a strip of mangroves between the bunds and the sea. Mangroves are known to reduce wave energy as waves travel through them. Thus, mangroves are used to protect the bunds from eroding. However, mangroves themselves are susceptible to erosion. Finding the best method in using this natural system of coastal protection is therefore important to the Department of Irrigation and Drainage. This paper looks at the various methods of using the systems developed to date.