Bacterial reduction of hexavalent molybdenum to molybdenum blue

A bacterium that was able to tolerate and reduce as high as 50 mM of sodium molybdate to molybdenum blue has been isolated from a metal recycling ground. The isolate was tentatively identified as Serratia sp. strain Dr.Y8 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. ANOVA analysis showed that isolate Dr.Y8 produced significantly higher (P < 0.05) amount of Mo-blue with 3, 5.1 and 11.3 times more molybdenum blue than previously isolated molybdenum reducers such as Serratia marcescens strain Dr.Y6, E. coli K12 and E. cloacae strain 48, respectively. Its molybdate reduction characteristics were studied in this work. Electron donor sources such as sucrose, mannitol, fructose, glucose and starch supported molybdate reduction. The optimum phosphate, pH and temperature that supported molybdate reduction were 5 mM, pH 6.0 and 37°C, respectively. The molybdenum blue produced from cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, silver, copper and mercury resulted in approximately 61, 57, 80, and 69% inhibition of the molybdenum-reducing activity at 1 mM, respectively. The reduction characteristics of strain Dr.Y8 suggest that it would be useful in future molybdenum bioremediation.     

Identification of a recurrent insertion mutation in the LDLR gene in a Pakistani family with autosomal dominant hypercholesterolemia

Familial Hypercholesterolemia (FH) results in elevated levels of blood lipids including total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) with normal triglycerides (TG). This disease is one of the major contributors towards an early onset of coronary heart disease (CHD). The aim of the present study was to identify the genes responsible for causing FH in Pakistani population, for this purpose a large consanguineous FH family was selected for genetic analysis. Serum lipid levels, including TC, TG, LDL-C and high density lipoprotein cholesterol (HDL-C), were determined in patients and healthy controls. In order to find the causative mutation in this family, direct sequencing of the low density lipoprotein receptor (LDLR) gene was performed. In addition the part of the Apolipoprotein-B (APOB) gene containing the mutations R3500Q and R3500W was also sequenced. Affected individuals of the family were found to have raised TC and LDL-C levels. Sequencing revealed an insertion mutation (c.2416_2417InsG) in exon 17 of the LDLR gene in all the affected individuals of the family. Common FH causing APOB mutations were not present in this family. Heterozygous individuals had TC levels ranging from ~300–500 mg/dl and the only homozygous individual with typical xanthomas had TC levels exceeding 900 mg/dl. This is the first report of a known LDLR gene mutation causing FH in the Pakistani population. Despite a large heterogeneity of LDLR mutations there are still some common mutations which are responsible for FH throughout the world.     

Histological and histoenzymological studies of medulla oblongata of Taphozous melanopogon Temminck (a Microchiroptera).

The paper deals with the histological and histoenzymological studies of the medulla oblongata of Taphozous melanopogon Temminck (a microchiropteran bat). Three phosphatases, namely acid phosphatase (ACP), thiamine pyrophosphatase (TTP) and glucose-6-phosphatase (G-6-P) were studied. All the enzymes were seen in all the neurons. The large neurons of the different nuclei are more strongly positive for ACP than the small neurons. Further, the areas which contain dense populations of neurons are more strongly stained than the area containing scattered neurons. TPP and G-6-P distributions are almost parallel to that of ACP. The functions of these enzymes in synthesis and secretory processes were discussed.     

Evaluation of the alleviative role of Chlorella vulgaris and Spirulina platensis extract against ovarian dysfunctions induced by monosodium glutamate in mice

Microalgae provide a wealthy natural resource of bioactive compounds, which have many biological activities. Monosodium glutamate is a food additive that acts either as food preservatives or as tastiness enhancer. It was confirmed that monosodium glutamate poses a serious responsibility in the pathogenesis of anovulatory infertility. Therefore, the idea of this research was directed to reveal efficiency of Chlorella vulgaris and Spirulina platensis extracts against the ovarian dysfunction resulted due to monosodium glutamate consumption. Adult female albino mice were gavages orally monosodium glutamate alone or with either Chlorella vulgaris or Spirulina platensis aqueous extracts for 28?days. Female mice were subjected to superovulation to study the oocytes nuclear maturation stages. Histological and quantitative investigation was carried on ovaries. Biochemical assessment to measure the sex hormones level and ovarian enzymatic antioxidants was done. In addition, ovarian antioxidant mRNA genes were determined using quantitative PCR and Glyceraldehyde-3-phosphate dehydrogenase was used as an internal control. The result revealed that monosodium glutamate reduced the oocytes quality and maturation rate, while, both algae improve the oocyte quality and maturation rate than in monosodium glutamate group. Chlorella vulgaris and Spirulina platensis improved the monosodium glutamate ovarian tissue histological alteration, sex hormones content and raised the ovarian enzymatic antioxidants level. In addition, monosodium glutamate markedly diminished the Glutathione peroxidase, superoxide dismutase and catalase mRNA expressions, However, Chlorella vulgaris or Spirulina platensis upregulated the expression of genes close to control. In conclusion, Chlorella vulgaris and Spirulina platensis showed potential alleviative role against the monosodium glutamate ovarian dysfunction.     

Do tropical forest leaves suffer more insect herbivory? A comparison of tropical versus temperate herbivory,estimated from leaf litter

It is generally believed that tropical forests suffer more herbivory, as a proportion of leaf area, than do temperate forests. Reviews so far have compared studies performed by different authors using very different methodologies. Here we carried out studies on 125 samples at 86 localities in eastern North America and on 75 samples taken at five localities in Malaysia and Singapore, including both mature secondary and primary forest. Samples in North America were spread over 3 years. In tropical Asia, the samples were taken at four time slices at least 8 months apart, scattered over a 4-year period. Total herbivore damage during the lifetime of tree leaves was estimated from the percentage area damaged in recently fallen, undecayed leaves from the forest floor, using scanner-linked software. In terms of percentage damage per leaf, the results suggest that lowland tropical forest has significantly higher leaf herbivory (5.82%) than temperate forest (5.48%). This is in accord with the general expectation that aseasonal tropical forests should have more herbivory damage. However, when percentage damage ‘per unit time of growing season’ is calculated based on an estimate of leaf lifetime in the tropics, tropical lowland herbivory damage turns out to be a fraction (about one half) of that in the temperate zone. Thus, these results tend to put in question the widely held view that herbivore damage is markedly more intense in the tropics. Over total leaf lifetime, the intensity of damage in the tropical area is only slightly higher than temperate regions. In terms of intensity of herbivory on leaves per unit of time, the opposite seems to be the case. It is uncertain which index should be taken as more significant in interpreting the selection pressure for anti-herbivore defenses in the tropics.     

Uromycladium tepperianum, the gall rust fungus from Falcataria moluccana in Malaysia and Indonesia

Batai (Falcataria moluccana) is a valuable tree species for forest plantations in Malaysia and Indonesia. Since 1993, a gall rust disease has caused severe damage to all growth stages, from seedlings in the nursery to mature trees in the field. To identify the fungus causing gall rust disease on F. moluccana in Malaysia and Indonesia, study of the mode of infection and changes in the anatomy of infected cells were carried out in the anatomy laboratory. The disease in Malaysia and Indonesia is caused by Uromycladium tepperianum. The fungus produces three longitudinally ridged teliospores on each head, with spores measuring 13–20 μm wide and 17–28 μm long. The fungus is microcyclic, completing its entire life cycle on F. moluccana. This study confirmed that the teliospores themselves cannot infect the host. Under favorable conditions, about 10 h after inoculation, teliospores germinate to produce basidiospores that form penetration pegs about 6 h later, and it is this peg which penetrates the host cells directly through the epidermis. Pycnia, recognized as small brown pustules, break through the epidermis about 7 days after inoculation.     

Purification and expression of glutathione S-transferase from a Malaysian population of Aedes albopictus (Diptera: Culicidae)

Glutathione S-transferase (GST) from the 4^th instar larvae of the dengue vector Aedes albopictus was purified by glutathione-agarose affinity chromatography and characterised using SDS-PAGE. The expression of the purified enzyme in the life stages and insecticide treated populations of Ae. albopictus as well as its cross-reactivity with larval GST of two dipteran species Aedes aegypti and Batrocera papayae were observed using western blotting. The purified GST had a specific activity of 196.0 ± 11 μmol/min/mg with a purification fold and yield of 28 and 69%, respectively. The SDS-PAGE analysis of the purified GST depicted a single band size of 23 kDa. The GST was expressed in all the larval and adult stages of Ae. albopictus with the exception of the pupal stage. However, the expression level in the adult stage was visibly reduced as compared to the larval stages. Western blotting analysis showed no cross-reactivity with the GST of Ae. aegypti (4^th instar) and B. papayae (3^rd instar) larvae. The expression of this enzyme was not inducible by exposure to the insecticides dichlorodiphenyltrichloroethane (1.25 mg/L) and malathion (0.3125 mg/L).