Alkaline protease in the midgut of the silkwormBombyx mori L: changes during metamorphosis

The protease activity in the midgut of bivoltine and muitivoltine races of the silkworm,Bombyx mori, was studied. The enzyme activity increased during fifth instar reached a peak, and decreased significantly through pre-pupal stage to the lowest level at the pupal stagTouring pharate adult period, the protease activity increased to reach another peak just before emergence of the moth, and decreased thereafter. The enzyme activity m bivoltmes was about 2–3 times higher than multivoltines at the peak levels. Bivoltines showed a sex difference in midgut protease activity while no significant difference was observed in multivoltines. Larvae and pharate adults showed a difference in the pH optima for the enzyme activity. From the results the possible role of midgut protease during the process of metamorphosis is discussed

Studies on the silk gland ofBomhyx mori: A comparative analysis during fifth instar development

Middle and posterior parts of the silk gland of fifth instar bivoltine and multivoltine races ofBombyx mori and their hybrid were analysed for the concentration of fibroin, DNA, RNA and total protein. Fibroin content of the silk gland increased rapidly from the beginning of fifth instar upto the spinning stage. Concentration of DNA in the middle silk gland was maximum at 24 hr and decreased thereafter. In the posterior silk gland, the concentration of DNA increased upto 72 hr and then decreased, RNA concentration was maximum at 72 hr and 120 hr, in the middle and posterior silk gland respectively. The total protein content increased gradually upto the spinning stage in the middle silk gland whereas it increased upto 120 hr and decreased sharply thereafter in the posterior silk gland. The difference in the concentration of these constituents in the silk gland was correlated with the differential silk output in both the pure races and their hybrid

Effect of Drought Stress on Proline Accumulation in Peanut Genotypes

The changes in the concentration of total protein, total free amino acids and free proline in the leaves of drought susceptible and drought tolerant varieties of peanut was studied under various durations of drought stress. In addition, the relative water content in the leaves was also analyzed. Under drought stress, the concentration of total protein was found to decrease in both drought susceptible and drought tolerant varieties and the degree of decrease was found to be higher in drought susceptible variety compared to drought tolerant variety. Whereas, the content of free amino acids was found to be higher in both the varieties and the increase in drought tolerant variety was found to be more significant than drought susceptible variety. The concentration of proline (a major osmolyte) was found to be significantly higher in the drought tolerant variety compared to drought susceptible variety. Further, the increase in the proline content under increasing drought stress (21 days) was found to be more than 2 folds in the tolerant variety when compared with susceptible variety. The relative water content was found to be inversely proportional to the proline accumulation. The results are discussed in the light of proline, acting as an osmolyte, facilitating the development of drought tolerance

Effect of Drought Stress on Epicuticular Wax Load in Peanut Genotypes

The changes in epicuticular wax load (EWL) and the leaf temperature in two peanut genotypes such as JL-24 (drought susceptible) and K-9 (drought tolerant) was studied under drought stress and its recovery. The drought stress was induced at different soil moisture level (100%, 60%, 40% and 20% FC) for 7 days and subsequent recovery for 7 days. In both JL-24 and K-9 genotypes, the EWL was found to be increase with the increase in the intensity of drought stress. However, the increase in EWL in K-9 genotype was found to be significantly higher than JL-24 genotype. Moreover, the leaf temperature was also found to be increased with the increase in the intensity of drought stress and the degree of increase in leaf temperature was more pronounced in JL-24 compared to K-9 genotype. Further, after the recovery of drought stress, the EWL and leaf temperature decreased consistently in both the genotypes. The results are discussed in terms of the differences in EWL and temperature of leaf in two genotypes studied under drought stres

Lead biosorption by a bacterium isolated from industrial effluents

An attempt was made to isolate microorganisms from the industrial effluents and to study their role in bioremediation of lead in selected industrial effluents. Sixty bacterial strains from the industrial effluent were isolated, purified, preliminarily identified and examd. for their ability to uptake lead. Based on the min. inhibition concns. (MICs) of lead for the selected isolates, six strains were found to be most resistant isolates and amongst them one isolate showed max. resistance to lead which was identified as Bacillus cereus. Scanning electron microscopic (SEM) photographs and Energy dispersive X-​ray spectroscopy (EDS) signature of Bacillus cereus revealed that lead was adsorbed to the cell surface, confirming biosorption capacity of the bacteria

Lead biosorption by resting cells of Bacillus cereus

A study on the lead biosorption by resting cells of lead resistant bacteria, isolated from industrial effluents, was carried out to ascertain their biosorption capacities. The strain showing highest MIC (min. inhibition concn.) for lead was selected for the study and identified as Bacillus cereus. Lead biosorption studies on Bacillus cereus pretreated with phys. (heat and oven dried) and chem. (sodium azide) methods showed improved lead biosorption with the exception of heat treatment in comparison to live biomass. Among the pretreatment methods, azide treatment showed max. lead biosorption.

Effect of lead on metallothionein concentration in lead-resistant bacteria Bacillus cereus isolated from industrial effluent

Metallothioneins (MTs) are cysteine-rich metal-binding proteins found in a wide variety of organisms including bacteria, fungi as well as all eukaryotic plant and animal species. MTs bind essential and nonessential heavy metals. MTs production was evaluated by a simple spectrophotometry methodology. The study elucidated that the metallothionein concentration in Bacillus cereus treated with different concentrations of lead increased with increasing lead concentration. The protein samples from B.cereus treated with different concentrations of lead were isolated and electrophoresed on SDS-PAGE and 2-D gels. The study of gels revealed that a thick protein band appeared around 14.3KD in case of B. cereus treated with lead unlike the control samples. © 2011 Academic Journals

Biosorption of lead by Bacillus cereus isolated from industrial effluents

Aims: To study the biosorption of lead ions from soln. using Bacillus cereus isolated from industrial effluents collected from Peenya industrial area, Bangalore, India and to det. the optimum conditions for biosorption. Study Design: Exptl. study. Place and Duration of Study: Department of Microbiol. and Biotechnol., Bangalore University, Bangalore, Karnataka, India, between Oct. 2008 and Dec. 2009. Methodol.: Sixty bacterial strains were isolated from industrial effluents collected from Peenya industrial area. Among the sixty isolates only six were selected for further investigation due to their high min. inhibition concn. for lead. Lead biosorption studies were carried out for all the six isolates using at. absorption spectrometry. The optimum conditions (temp., pH and culture age) for biosorption were detd. for the isolate showing highest lead biosorption. Results: The lead biosorption capability of all six isolates was studied at different concns. of lead (100, 200, 300, 400 and 500 mg​/l)​. The isolate 6 showed highest lead biosorption capability and was identified as Bacillus cereus. Studies on the control of environmental factors revealed that an optimum temp. of 30°C and pH 5, facilitates max. biosorption of lead by 24h old culture of Bacillus cereus. Conclusion: Biosorption is an alternative to traditional physicochem. methods for removing toxic metals from wastewaters. The results of this study are discussed in the light of the biosorption capacity of Bacillus cereus that could be exploited in the bioremediation of lead

Effect of Lead on Growth, Protein and Biosorption Capacity of Bacillus Cereus Isolated from Industrial Effluen

A bacterial strain (Bacillus cereus) with the ability to grow under conditions of high concentrations of lead was isolated from the industrial effluent collected from Peenya Industrial Area, Bangalore. The effect of lead on growth, protein content and lead biosorption capacity of Bacillus cereus was investigated. The results revealed that with increase in lead concentration (100, 200, 300, 400 and 500 mg l-1) there was a decrease in growth, protein content (10.6, 8.2, 6.7, 3.8 and 1.9 mg g-1 d. wt.) and lead biosorption ( 90.3, 57.8, 48.94, 31.3 and 22.24 %) Bacillus cereus, signifying toxic effect of lead on the bacterial strain. Plasmid DNA was isolated from Bacillus cereus to study its resistance mechanism. The size of the plasmid was approximately 33kb. Transformation results suggest that lead resistance gene may be present on the chromosomal DNA rather than the plasmid DNA as the transformants did not show lead resistanc

Neonatal exposure to 17β-estradiol down-regulates the expression of synaptogenesis related genes in selected brain regions of adult female rats

Aims Administration of estradiol or compounds with estrogenic activity to newborn female rats results in irreversible masculinization as well as defeminization in the brain and the animals exhibit altered reproductive behavior as adults. The cellular and molecular mechanism involved in inducing the irreversible changes is largely unknown. In the present study, we have monitored the changes in the expression of selected synaptogenesis related genes in the sexually dimorphic brain regions such as POA, hypothalamus and pituitary following 17β-estradiol administration to neonatal female rats. Main methods Female Wistar rats which were administered 17β-estradiol on day 2 and 3 after birth were sacrificed 120 days later and the expression levels of genes implicated in synaptogenesis were monitored by semi-quantitative reverse transcription PCR. Since estradiol induced up-regulation of COX-2 in POA is a marker for estradiol induced masculinization as well as defeminization, in the present study only animals in which the increase in expression of COX-2 gene was observed in POA were included in the study. Key findings Down-regulation of genes such as NMDA-2B, NETRIN-1, BDNF, MT-5 MMP and TNF-α was observed in the pre-optic area of neonatally E2 treated female rat brain but not in hypothalamus and pituitary compared to the vehicle- treated controls as assessed by RT-PCR and Western blot analysis. Significance Our results suggest a possibility that down-regulation of genes associated with synaptogenesis in POA, may be resulting in disruption of the cyclical regulation of hormone secretion by pituitary the consequence of which could be infertility and altered reproductive behavior