Behavior of bacteriophage Mu DNA upon infecton of Escherichia coli cells.

The question whether the ends of bacteriophage Mu DNA are fused to form a ring in host cells is critical to the understanding of the mechanism of integrative recombination between Mu DNA and host DNA. We have examined the fate of ³²P-labeled Mu DNA, after infection of sensitive and immune (lysogenic) cells, by sedimentation in sucrose gradients, ethidium bromide/CsCl density centrifugation and by electrophoresis of parental Mu DNA and its fragments in agarose gels. We find that the parental Mu DNA cannot be detected as covalently closed circles at any stage during the Mu life cycle. An interesting form of Mu DNA can be seen after superinfection of immune cells. This form sediments about twice as fast as the mature phage DNA marker in neutral sucrose gradients but yields linear molecules upon phenol extraction. Upon infection of sensitive cells, most of the parental DNA associates with a large complex, presumably containing the host chromosome. When Mu-sensitive cells are infected with unlabeled Mu particles and Mu DNA examined at different times after infection by fractionation in 0.3% agarose gels and hybridization with ³²P-labeled Mu DNA, Mu sequences are found to appear with the bulk host DNA as the phage lytic cycle progresses. However, no distinct replicative or integrative intermediate of Mu, that behaves differently from linear Mu DNA and is separate from the host DNA, can be detected.     

Bacteriophage Mu-induced modification of DNA is dependent upon a host function.

The DNA of bacteriophage Mu, extracted from induced lysates, is partially resistant to digestion by the endonuclease BalI. This modification of DNA is controlled by the Mu modification function (mom), which acts in conjunction with the dam (DNA-adenine methylation) function of Escherichia coli. Since the BalI recognition site is apparently different from the dam recognition site, these results imply that either the specificity of the dam function is changed by the mom function or the mom function requires the dam function for its activity.     

Metagenomics analysis of the fecal microbiota in Ring-necked pheasants (Phasianus colchicus) and Green pheasants (Phasianus versicolor) using next generation sequencing

Pheasant reintroduction and conservation efforts have been in place in Pakistan since the 1980 s, yet there is still a scarcity of data on pheasant microbiome and zoonosis. Instead of growing vast numbers of bacteria in the laboratory, to investigate the fecal microbiome, pheasants (green and ring neck pheasant) were analyzed using 16S rRNA metagenomics and using IonS5TMXL sequencing from two flocks more than 10 birds. Operational taxonomic unit (OTU) cluster analysis and phylogenetic tree analysis was performed using Mothur software against the SSUrRNA database of SILVA and the MUSCLE (Version 3.8.31) software. Results of the analysis showed that firmicutes were the most abundant phylum among the top ten phyla, in both pheasant species, followed by other phyla such as actinobacteria and proteobacteria in ring necked pheasant and bacteroidetes in green necked pheasant. Bacillus was the most relatively abundant genus in both pheasants followed by Oceanobacillus and Teribacillus for ring necked pheasant and Lactobacillus for green necked pheasant. Because of their well-known beneficial characteristics, these genus warrants special attention. Bird droppings comprise germs from the urinary system, gut, and reproductive sites, making it difficult to research each anatomical site at the same time. We conclude that metagenomic analysis and classification provides baseline information of the pheasant fecal microbiome that plays a role in disease and health.     

Characterization of antifungal metabolites produced by Lactobacillus plantarum and Lactobacillus coryniformis isolated from rice rinsed water

Molecular Biology Reports - A recent spike in demand for chemical preservative free food has derived the scientific community to develop natural ways of food preservation. Therefore,...     

Variations in random amplified polymorphic DNA profile and toxin production among isolates of Colletotrichum falcatum Went from sugarcane in Tamil Nadu,India

Red rot, caused by Colletotrichum falcatum Went, is one of the most important diseases of sugarcane (Saccharum officinarum L.). The pathogen shows a great diversity in virulence as a number of pathotypes are known to occur in nature. In the present study, the toxin producing ability and genetic variability among isolates of C. falcatum collected from major sugarcane growing areas of Tamil Nadu, India were analysed. The C. falcatum isolates differed significantly in their ability to produce toxin in vitro. The toxin from C. falcatum isolate Cf 671a induced the maximum electrolyte leakage (300 μS) from sugarcane leaf tissues. The genetic relatedness of the isolates of C. falcatum differing in toxin production potential was investigated by using RAPD analysis. Analysis of the genetic coefficient matrix derived from the scores of RAPD profiles showed that minimum and maximum percent similarities among the tested C. falcatum isolates were in the range of 19 to 95% respectively. The phylogenetic analysis by the UPGMA identified two main clusters. Cluster A contains only one isolate (Cf 98061) and all the other isolates were placed in Cluster B confirming high genetic diversity among the isolates. No correlation was observed between clustering of the C. falcatum isolates in the dendrogram and their toxin producing abilities.     

DNA electromagnetic properties and interactions -An investigation on intrinsic bioelectromagnetism within DNA

The question whether intrinsic bioelectromagnetism exists within DNA or not is an important and so far unexplored area of biology. We carried out a study of isolated genetic material, utilizing both prokaryotic and eukaryotic DNA, to measure any possible intrinsic electromagnetic effects or fields emanated within the molecules. Studies were carried out with extremely sensitive ultra-low-noise trans-impedance amplifiers and a high-precision data acquisition system to record any possible faintest electromagnetic signals from the concentrated, as well as diluted DNA, in vitro. Some experiments were performed to investigate any possible electromagnetic effects of high-frequency (HF) RF fields on the DNA under test. However, after extensive testing and careful measurements, we failed to detect any possible intrinsic or induced electromagnetic activity from the DNA as compared to simple water or empty chambers. We reached a conclusion that there does not seem to be any measurable intrinsic electromagnetic activity or fields present in the DNA material, whether in concentrated or diluted form, and if there were, any such activity or fields would be extremely minuscule to be detected with scientific precision by current human measurement methods.     

Oxidative stress elevated DNA damage and homocysteine level in normal pregnant women in a segment of Pakistani population

Maternal oxidative stress during pregnancy may impair fetal growth and help in the development of diseases in adulthood. The aim of current study was to assess total oxidation status (TOS), related parameters and their relationship to DNA damage (%) and homocysteine level in normal pregnant women in low-income participants. In a cross-sectional study healthy women were grouped as normal, while age matched nulliparous and singleton pregnancies were included for first, second and third trimester groups. TOS (P < 0.01), melanodialdehyde (MDA) (P < 0.001), aspartate aminotransferase (AST) (P < 0.01), triiodothyronine (T3) (P < 0.01), thyroxine (T4) (P < 0.01), and homocysteine (P < 0.001), in pregnant women were significantly higher as compared to normal healthy women. While serum total proteins (P < 0.01), albumin (P < 0.01) and total antioxidant status (TAS) (P < 0.001) decreased significantly as compared to normal healthy women. Women in third trimester showed a significantly high level of body temperature (P < 0.01), triglyceride (P < 0.01), LDL-cholesterol (P < 0.05), AST (P < 0.01), T3 (P < 0.01), homocysteine (P < 0.001), TOS (P < 0.01) and MDA (P < 0.001) but a lower concentration of serum proteins, albumin and TAS at the end of the pregnancy. Pearson correlation indicated a positive relationship of homocysteine with triglycerides (P < 0.027), TOS (P < 0.01), MDA (P < 0.035) and had a negative relationship with total protein (P < 0.026). DNA damage was strongly related with T3 (P < 0.008), TOS (P < 0.02), MDA (P < 0.037) and MBI (P < 0.048) profiles of pregnant women. These changes were considered normal for pregnant women having optimum blood pressure and normal child birth. Hormonal influences and hemodilution may contribute towards the observed changes in this study.     

Development of Controlled-Release Matrix Tablet of Risperidone: Influence of Methocel®- and Ethocel®-Based Novel Polymeric Blend on <Emphasis Type="Italic">In Vitro</Emphasis> Drug Release and Bioavailability

Controlled-release (CR) matrix tablet of 4 mg risperidone was developed using flow bound dry granulation–slugging method to improve its safety profile and compliance. Model formulations F1, F2, and F3, consisting of distinct blends of Methocel® K100 LV-CR and Ethocel® standard 7FP premium, were slugged. Each batch of granules (250–1,000 μm), obtained by crushing the slugs, was divided into three portions after lubrication and then compressed to 9-, 12-, and 15-kg hard tablets. In vitro drug release studies were carried out in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) using a paddle dissolution apparatus run at 50 rpm. The CR test tablet, containing 30% Methocel® and 60% Ethocel® (F3) with 12-kg hardness, exhibited pH-independent zero-order release kinetics for 24 h. The drug release rate was inversely proportional to the content of Ethocel®, while the gel layer formed of Methocel® helped in maintaining the integrity of the matrix. Changes in the hardness of tablet did not affect the release kinetics. The tablets were reproducible and stable for 6 months at 40 ± 2°C/75 ± 5% relative humidity. Risperidone and its active metabolite, 9-hydroxyrisperidone, present in the pooled rabbit’s serum, were analyzed with HPLC-UV at λ_max 280 nm. The CR test tablet exhibited bioequivalence to reference conventional tablet in addition to the significantly (p < 0.05) optimized peak concentration, C_max, and extended peak time, T_max, of the active moiety. There was a good association between drug absorption in vivo and drug release in vitro (R² = 0.7293). The successfully developed CR test tablet may be used for better therapeutic outcomes of risperidone.KEY WORDS: controlled release, dry granulation slugging method, risperidone