Biologically active macrocyclic complexes derived from diaminonaphthalene and glyoxal: Template synthesis and spectroscopic approach

A novel series of complexes of the type [M(C(24)H(16)N(4))X(2)]; where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); X = Cl(-1), NO(-1)(3), CH(3)COO(-1) has been synthesized by template condensation of 1,8-diaminonaphthalene and glyoxal in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, molecular weight determination, magnetic measurements, electronic, NMR, infrared and far infrared spectral studies. The low value of molar conductance indicates them to be non-electrolytes. On the basis of various studies a distorted octahedral geometry may be proposed for all of these complexes. These metal complexes were also tested for their in vitro antibacterial and antifungal activities to assess their inhibiting potential.     

Transbuccal Delivery of 5-Fluorouracil: Permeation Enhancement and Pharmacokinetic Study

The purpose of this study was to determine the effect of permeation enhancers on the transbuccal delivery of 5-fluorouracil (FU). The effect of permeation enhancers on in vitro buccal permeability was assessed using sodium deoxycholate (SDC), sodium dodecyl sulphate (SDS), sodium tauroglycocholate (STGC), and oleic acid and their concentrations for absorption enhancement were optimized. STGC appeared to be most effective for enhancing the buccal permeation of FU than the other enhancers. These enhancements by STGC were statistically significant (p < 0.05) compared to control. The order of permeation enhancement was STGC > SDS > SDC > oleic acid. Histological investigations were performed on buccal mucosa and indicated no major morphological changes. The enhancing effect of STGC on the buccal absorption of FU was evaluated from the mucoadhesive gels in rabbits. The absolute bioavailability of FU from mucoadhesive gels containing STGC increased 1.6-fold as compared to the gels containing no permeation enhancer. The mean residence time and mean absorption time considerably increased following administration of gel containing penetration enhancer compared with the gel without penetration enhancer.     

Behavioural and Electrophysiological Responses of Mosquito Vectors <Emphasis Type="Italic">Aedes aegypti,Anopheles stephensi</Emphasis> and <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> to an Ethyl Ester: Ethyl 2-aminobenzoate

Mosquito control using different methods remains an integral component of intervention programmes which aim to protect humans from various mosquito-borne diseases. The host seeking behaviour of mosquitoes is essentially guided by odorant receptor neurons housed in the antenna, maxillary palps and proboscis. The odorant receptor neurons are responsible for detecting chemical cues from hosts and also useful for developing sustainable mosquito-control strategies that exploit host-seeking behaviours. The present investigation evaluates host seeking behavioural responses of a novel, non-toxic and environment friendly repellent, ethyl 2-aminobenzoate against three known vector species of mosquitoes viz. Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus maintained in laboratory. The flight orientation of the test mosquitoes was studied using Y-tube olfactometer, whereas the antennae of adult female mosquitoes were used to investigate the effect of ethyl 2-aminobenzoate on the peripheral olfactory system using electroantennogram (EAG). The findings demonstrate that ethyl 2-aminobenzoate exhibited significant response in Y-tube olfactometer against all the three known vector species of mosquitoes. However, only Anopheles stephensi significantly elicited responses in EAG experiments, while the responses obtained for Aedes aegypti and Culex quinquefasciatus were not statistically significant. The results conclude that currently evaluated chemical ethyl 2-aminobenzoate has potential against some well established mosquito vector species and could be exploited to develop new and comparatively more effective anti-mosquito formulations.     

Binding of Ca2+ to glutamic acid-rich polypeptides from the rod outer segment

Rod photoreceptors contain three different glutamic acid-rich proteins (GARPs) that have been proposed to control the propagation of Ca(2+) from the site of its entry at the cyclic nucleotide-gated channel to the cytosol of the outer segment. We tested this hypothesis by measuring the binding of Ca(2+) to the following five constructs related to GARPs of rod photoreceptors: a 32-mer peptide containing 22 carboxylate groups, polyglutamic acid, a recombinant segment comprising 73 carboxylate groups (GLU), GARP1, and GARP2. Ca(2+) binding was investigated by means of a Ca(2+)-sensitive electrode. In all cases, Ca(2+) binds with low affinity; the half-maximum binding constant K(1/2) ranges from 6 to 16 mM. The binding stoichiometry between Ca(2+) ions and carboxylic groups is approximately 1:1; an exception is GARP2, where a binding stoichiometry of approximately 1:2 was found. Hydrodynamic radii of 1.6, 2.8, 3.3, 5.7, and 6.7 nm were determined by dynamic light scattering for the 32-mer, polyglutamic acid, GLU, GARP2, and GARP1 constructs, respectively. These results suggest that the peptides as well as GARP1 and GARP2 do not adopt compact globular structures. We conclude that the structures should be regarded as loose coils with low-affinity, high-capacity Ca(2+) binding.     

Mesodermal expression of integrin α5β1 regulates neural crest development and cardiovascular morphogenesis

Integrin α5-null embryos die in mid-gestation from severe defects in cardiovascular morphogenesis, which stem from defective development of the neural crest, heart and vasculature. To investigate the role of integrin α5β1 in cardiovascular development, we used the Mesp1^Cre knock-in strain of mice to ablate integrin α5 in the anterior mesoderm, which gives rise to all of the cardiac and many of the vascular and muscle lineages in the anterior portion of the embryo. Surprisingly, we found that mutant embryos displayed numerous defects related to the abnormal development of the neural crest such as cleft palate, ventricular septal defect, abnormal development of hypoglossal nerves, and defective remodeling of the aortic arch arteries. We found that defects in arch artery remodeling stem from the role of mesodermal integrin α5β1 in neural crest proliferation and differentiation into vascular smooth muscle cells, while proliferation of pharyngeal mesoderm and differentiation of mesodermal derivatives into vascular smooth muscle cells was not defective. Taken together our studies demonstrate a requisite role for mesodermal integrin α5β1 in signaling between the mesoderm and the neural crest, thereby regulating neural crest-dependent morphogenesis of essential embryonic structures.     

Infection of Bacterial Endosymbionts in Insects: A Comparative Study of Two Techniques viz PCR and FISH for Detection and Localization of Symbionts in Whitefly,Bemisia tabaci

Bacterial endosymbionts have been associated with arthropods and large number of the insect species show interaction with such bacteria. Different approaches have been used to understand such symbiont- host interactions. The whitefly, Bemisia tabaci, a highly invasive agricultural pest, harbors as many as seven different bacterial endosymbionts. These bacterial endosymbionts are known to provide various nutritional, physiological, environmental and evolutionary benefits to its insect host. In this study, we have tried to compare two techniques, Polymerase chain reaction (PCR) and Flourescence in situ Hybridisation (FISH) commonly used for identification and localization of bacterial endosymbionts in B. tabaci as it harbors one of the highest numbers of endosymbionts which have helped it in becoming a successful global invasive agricultural pest. The amplified PCR products were observed as bands on agarose gel by electrophoresis while the FISH samples were mounted on slides and observed under confocal microscope. Analysis of results obtained by these two techniques revealed the advantages of FISH over PCR. On a short note, performing FISH, using LNA probes proved to be more sensitive and informative for identification as well as localization of bacterial endosymbionts in B. tabaci than relying on PCR. This study would help in designing more efficient experiments based on much reliable detection procedure and studying the role of endosymbionts in insects.     

Cloning and characterization of a thermostable H2O-forming NADH oxidase from Lactobacillus rhamnosus

NADH oxidase (Nox) catalyzes the conversion of NADH to NAD(+). A previously uncharacterized Nox gene (LrNox) was cloned from Lactobacillus rhamnosus and overexpressed in Escherichia coli BL21(DE3). Sequence analysis revealed an open reading frame of 1359 bp, capable of encoding a polypeptide of 453 amino acid residues. The molecular mass of the purified LrNox enzyme was estimated to be ~50 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 100 kDa by gel filtration chromatography, suggesting that the enzyme is a homodimer. The enzyme had optimal activity at pH 5.6 and temperature 65 °C, and k(cat)/K(m) of 3.77×10(7) s(-1) M(-1), the highest ever reported. Heat inactivation studies revealed that LrNox had high thermostability, with a half-life of 120 min at 80 °C. Molecular dynamics simulation studies shed light on the factors contributing to the high activity of LrNox. Although the properties of Nox from several microorganisms have been reported, this is the first report on the characterization of a recombinant H(2)O-forming Nox with high activity and thermostability. The characteristics of the LrNox enzyme could prove to be of interest in industrial applications such as NAD(+) regeneration.     

In Vitro Matured Oocytes Are More Susceptible than In Vivo Matured Oocytes to Mock ICSI Induced Functional and Genetic Changes

Background

Concerns regarding the safety of ICSI have been intensified recently due to increased risk of birth defects in ICSI born children. Although fertilization rate is significantly higher in ICSI cycles, studies have failed to demonstrate the benefits of ICSI in improving the pregnancy rate. Poor technical skill, and suboptimal in vitro conditions may account for the ICSI results however, there is no report on the effects of oocyte manipulations on the ICSI outcome.

Objective

The present study elucidates the influence of mock ICSI on the functional and genetic integrity of the mouse oocytes.

Methods

Reactive Oxygen Species (ROS) level, mitochondrial status, and phosphorylation of H2AX were assessed in the in vivo matured and IVM oocytes subjected to mock ICSI.

Results

A significant increase in ROS level was observed in both in vivo matured and IVM oocytes subjected to mock ICSI (P<0.05-0.001) whereas unique mitochondrial distribution pattern was found only in IVM oocytes (P<0.01-0.001). Importantly, differential H2AX phosphorylation was observed in both in vivo matured and IVM oocytes subjected to mock ICSI (P <0.001).

Conclusion

The data from this study suggests that mock ICSI can alter genetic and functional integrity in oocytes and IVM oocytes are more vulnerable to mock ICSI induced changes.