Purification and dose-dependent toxicity study of abrin in swiss albino male mice.

Abrin, a phytotoxin obtained from the seeds of the Abrus precatorius plant, is highly toxic with an estimated human fatal dose of 0.1­1 µg/kg. In this study, abrin was purified and characterized through SDS PAGE and mass spectrometry analysis; further study on toxicity was carried out to investigate the alteration in biochemical, and hematological variables through histopathological observations in mice. The intraperitoneal LD50 value of purified abrin for mice was found to be 0.91µg/kg of body weight. Mice were exposed to 0.4 and 1.0 LD50 abrin doses intraperitoneally and observed on days 1, 3, and 7. Plasma GOT and GPT levels increased significantly at both doses. At 1.0 LD50 dose, alkaline phosphatase, bilirubin, urea, uric acid, and creatinine levels increased, whereas albumin, total protein, glucose and cholesterol levels decreased significantly. Abrin intoxication also altered the hemoglobin, WBC, and RBC counts significantly at 1.0 LD50 dose. Liver GSH levels decreased while lipid peroxidation increased significantly in a dose­dependent manner. Biochemical changes were supported by the histological investigation, which also showed the degenerative changes in organs. In conclusion, abrin intoxication caused toxic effects and severe damages on studied organs mediated through alteration in biochemical and hematological variables, lipid peroxidation, and degeneration.

Novel magnetism of Ir5+(5d4) Ions in the double perovskite Sr2YIrO6.

We synthesize and study single crystals of a new double-perovskite Sr2YIrO6. Despite two strongly unfavorable conditions for magnetic order, namely, pentavalent Ir5+(5d4) ions which are anticipated to have Jeff=0 singlet ground states in the strong spin-orbit coupling (SOC) limit and geometric frustration in a face-centered cubic structure formed by the Ir5+ ions, we observe this iridate to undergo a novel magnetic transition at temperatures below 1.3 K. We provide compelling experimental and theoretical evidence that the origin of magnetism is in an unusual interplay between strong noncubic crystal fields, local exchange interactions, and "intermediate-strength" SOC. Sr2YIrO6 provides a rare example of the failed dominance of SOC in the iridates.

ZnO nanoparticles induced exopolysaccharide production by B. subtilis strain JCT1 for arid soil applications.

ZnO nanoparticle induced exopolysaccharide (EPS) production from Bacillus subtilis strain JCT1 (NCBI GenBank Accession No. JN194187) is a novel approach for arid soil applications. In the series of investigations, environmentally benign protocol was followed for the synthesis of ZnO nanoparticles using extracellular enzymes obtained from Aspergillus fumigatus TFR8. Putative characterization techniques were employed for confirmation of size, shape, surface structure, crystalline nature and elemental proportion of ZnO nanoparticles. Results established an average size of ZnO nanoparticles to be 2.9 nm at least at one dimension and oblate spherical in structure. The qualitative composition of the nanoparticles exhibited 97.5% Zn element atom percentage. Biosynthesized ZnO nanoparticles enhanced exopolysaccharide production by 596.1% as compared to control and further EPS amelioration led to enhanced soil aggregation (up to 82%), moisture retention (10.7-14.2%) and soil organic carbon. Soil aggregation stability was further confirmed by Fourier transform infra-red spectroscopy. A possible ZnO nanoparticle mediated biological mechanism for enhancing exopolysaccharide production has been discussed.

Space radiation transport properties of polyethylene-based composites.

Composite materials that can serve as both effective shielding materials against cosmic-ray and energetic solar particles in deep space, as well as structural materials for habitat and spacecraft, remain a critical and mission enabling component in mission planning and exploration. Polyethylene is known to have excellent shielding properties due to its low density, coupled with high hydrogen content. Polyethylene-fiber reinforced composites promise to combine this shielding effectiveness with the required mechanical properties of structural materials. Samples of polyethylene-fiber reinforced epoxy matrix composite 1-5 cm thick were prepared at the NASA Marshall Space Flight Center and tested against a 500 MeV/nucleon Fe beam at the HIMAC facility of NIRS in Chiba, Japan. This paper presents measured and calculated results for the radiation transport properties of these samples.

The effect of antidepressants on serum melatonin levels in endogenous depression.

OBJECTIVES: 1. To assess the serum melatonin levels in patients suffering from endogenous depression and the effect of pharmacological therapy. 2. To establish possible correlation between the height from the mean sea levels and the patients suffering from endogenous depression. METHODS: Forty patients, 18 males and 22 females, suffering from endogenous depression (according to DSM IV criteria), aged 48.3 +/- 12.32 years were evaluated and serum melatonin level was assayed between 9-10 am. They were not on any drugs/medication, which was likely to alter serum melatonin level for one month prior to study. The serum melatonin levels were assessed at 0, 3, 6 and 12 months while they were continued to be treated. It also included 30 controls of the matched age and sex and satisfying the inclusion criteria. The possible correlation was also studied between the serum levels and the height from the mean sea level at which the patients reside. RESULTS: The two groups were comparable at the beginning of the study. The serum melatonin levels started falling from three months onwards (from 9.99 +/- 3.59 pg/nl to 8.49 +/- 3.16 pg/nl; p < 0.05). However, the decline was maximum between 3-6 months (from 8.49 +/- 3.16 to 5.589 +/- 1.96; p<0.05). The serum levels became stationary beyond six months. Highest melatonin levels were observed in patients residing at an altitude of 6001-8000 metres (14.32 +/- 2.68 pg/ml; p < 0.05) followed by 4,001-6,000 meters (11.137 +/- 2.62 pg/ml; p < 0.05). However, the levels were almost stationary below 4,000 metres (p = 0.05). CONCLUSION: 1. Higher serum melafonin values were observed in patients suffering from endogenous depression. 2. Morning serum melatonin values decreased with pharmacological therapies. 3. Patients living at higher altitudes had higher serum values for the hormone.

Gas chromatographic detection of anaerobic bacteria from environment.

A rapid method of detection of anaerobic bacteria in environment using gas chromatograph is described. Metabolically produced volatile and non-volatile fatty acid by the anaerobic bacteria are detected gas-chromatographically. Using this technique anaerobic bacteria are detected from soil, air, laboratory and operation theatre environments and drinking water samples. In the polluted drinking water apart from drug resistant E. coli, Clostridium difficile is isolated indicating faecal pollution of drinking water from cases of antibiotic associated pseudomembraneous colitis. The method has great significance in detection of anaerobic bacteria in environment especially in the management of war wounds.

The deduced protein sequence of the human carboxypeptidase N high molecular weight subunit reveals the presence of leucine-rich tandem repeats.

Human plasma carboxypeptidase N is a 280-kDa tetramer with two high molecular mass (83-kDa) glycosylated subunits which protect the two 50-kDa catalytic subunits and keep them in the circulation. An initial clone for the 83-kDa subunit was obtained by screening two lambda gt11 human liver cDNA expression libraries with antiserum specific for carboxypeptidase N or the 83-kDa subunit. The libraries were rescreened with the labeled cloned cDNA, and the largest clone obtained (2536-base pair insert) was completely sequenced. The deduced protein sequence matched the sequence of several tryptic peptides from the 83-kDa subunit but did not contain the NH2-terminal sequence. The remaining portion of the protein coding sequence was synthesized by the polymerase chain reaction, cloned, and sequenced. The composite cDNA sequence is 2870 base pairs long with an open reading frame of 1608 base pair coding for a protein of 536 amino acids (Mr = 58,762). The protein sequence contains seven potential N-linked glycosylation sites and a threonine/serine-rich region which is a potential site for attachment of O-linked carbohydrate. The most striking feature is a region (residues 68-355) containing 12 leucine-rich tandem repeats of 24 residues with the following consensus sequence: P-X-X-alpha-F-X-X-L-X-X-L-X-X-L-X-L-X-X-N-X-L-X-X-L (X = any amino acid and alpha = aliphatic amino acids, I, L, or V). This repeating pattern is found in the leucine-rich alpha 2-glycoprotein and in other proteins where it might mediate interactions with macromolecules. This region also contains five sequences with heptad repeating leucine residues comprising a leucine zipper motif. The leucine-rich domain likely constitutes an important structural or functional element in the interactions of the 83- and 50-kDa subunits to form the active tetramer of carboxypeptidase N.

Isolation and characterization of human blood-coagulation factor X cDNA.

Using synthetic oligodeoxynucleotides as probes, we have isolated factor X cDNA from human liver cDNA library. We sequenced the 1430-bp cDNA which spans the coding region of the mature factor X and contains the polyadenylation signal and poly(A) tail. The amino acid (aa) sequence is in agreement with the published aa sequence. The nucleotide (nt) sequence of cDNA confirmed that factor X is synthesized and secreted as a single-chain precursor, and then converted into dimeric form by proteolytic cleavage of an internal tripeptide. From the nt sequence, it was also predicted that like other secretory proteins, human factor X is synthesized with a leader sequence (prepro-protein). The 5'-coding region of factor X cDNA is 60 and 40% homologous to the corresponding regions of factor IX and prothrombin genes, respectively. This supports the hypothesis of gene evolution by gene duplication followed by divergence.

DNA sequence analysis: a procedure to find homologies among many sequences.

SEQCMP, a program that analyzes and searches for homology among multiple nucleic acid sequences, is described. The sequences are compared by the dot matrix method and the consensus sequence is derived by superimposing all the dot matrices on one another. The program is written in MBASIC and runs on IBM-PC microcomputer. It is interactive and can be used by investigators with no computer background or experience.

Hemoglobin binds to the amino-terminal 23-residue fragment of human erythrocyte band 3 protein.

Hemoglobin, aldolase and glyceraldehyde 3-phosphate dehydrogenase are known to bind to the cytoplasmic domain of band 3 protein. Binding of glycolytic enzymes to band 3 protein is inhibited by its amino-terminal fragments. To precisely localize the sequence portion of band 3 protein to which hemoglobin binds and to see whether the same region of amino-acid sequence binds both hemoglobin and glycolytic enzymes, a simple, direct solid-phase binding assay was developed. Peptides generated from the 23-kDa fragment by trypsin, cyanogen bromide and mild acid hydrolysis were used as inhibitors to determine the minimal sequence structure involved in the binding of the 23-kDa fragment to hemoglobin. The shortest peptide which inhibits the binding of the 23-kDa fragment is an acid cleavage peptide containing the sequence positions 1 to 23. This sequence is unusual as 14 of its residues are negatively charged, it contains no basic residues and has its amino terminus blocked. Using aldolase, glyceraldehyde-3-phosphate dehydrogenase and hemoglobin as competitive inhibitors in the binding of 23-kDa fragment, the affinity of hemoglobin to this fragment appears several-fold weaker than that of both the enzymes. These findings demonstrate that glycolytic enzymes and hemoglobin bind competitively to the same polyanionic sequence region of band 3 protein.

Interaction of hemoglobin with band 3: a review.

The oxygen transport protein hemoglobin interacts specifically and reversibly with the red cell membrane. pH and ionic strength dependence of these interactions indicate their electrostatic nature. The anion transport protein band 3 has been implicated as the protein to which hemoglobin binds. Hemoglobin, aldolase and glyceraldehyde 3-phosphate dehydrogenase have a similar pH and ionic strength dependence in binding to 23K fragment. The three compete for the same amino-terminal 23 residue sequence region of band 3. The binding site is a highly acidic segment without any positive charge. We have recently determined the sequence of amino-terminal 23K fragment of band 3. There is a remarkable internal sequence homology between the first eleven and next eleven residues in this sequence region. Biophysical measurements in this sequence region. Biophysical measurements have revealed that 23K is a tetramer under physiological conditions. The implications of this structure of 23K is discussed with respect to the interaction of band 3 with the red cell cytoskeleton.

Amino acid sequence of the N alpha-terminal 201 residues of human erythrocyte membrane band 3.

We have determined the amino acid sequence of the N alpha-terminal portion of band 3, the anion transport protein of the human erythrocyte membrane. The material analyzed was a 201-residue, 23,053-Da fragment cleaved from the cytoplasmic end of band 3 by S-cyanylation. The sequence had these notable features. 1) The N alpha-terminal region was extraordinarily acidic, second only to a segment of similar size from the sigma factor of Escherichia coli RNA polymerase. The first 33 residues contained 6 aspartic acid and 12 glutamic acid residues, no basic residue, and a blocked N alpha-amino group. 2) The first 11 residues of the protein had a striking resemblance to the following 11 residues. 3) In contrast to the acidic N alpha-terminal third, the COOH-terminal two-thirds of the 23,053-Da fragment had a predominantly basic character. The highly acidic character of the N alpha-terminal portion of band 3 accounts for the capacity of this part of the protein to bind glycolytic enzymes in a highly electrostatic fashion, presumably through interaction with their cationic substrate-binding sites.

On a new species of Capillaria (Nematoda) from a bat in Kashmir.

Capillaria kashmirensis n. sp. from the stomach of a bat in Kashmir, India, is described. The species is characterized by the presence of a funnel-like bursa in males which is deeply incised ventrally. The bursa is supported by a pair of long papillae. Lateral alae, a single spicule and an unarmed spicule sheath are present. The ratio between anterior and posterior regions of the body is 1:1.2 to 1.57 and the spicule body length ratio is 1:9 to 15. Cloaca is terminal. In females the tail is blunt, the anus sub-terminal, the ulva post-oesophageal, situated on a vulvar appendage.

The aldolase-binding site of the human erythrocyte membrane is at the NH2 terminus of band 3.

Band 3 is the predominant membrane-spanning polypeptide and the mediator of anion transport in the human erythrocyte. In addition, it provides the sites of association for fructose 1,6-bisphosphate aldolase and other cytoplasmic proteins with the membrane. The aldolase-binding activity of water-soluble fragments of band 3 was measured by their inhibition of aldolase catalytic activity and by their displacement of aldolase from ghosts. At saturation, the binding of one band 3 or certain of its fragments per aldolase molecule partially inhibited the catalytic activity and band 3 binding of the unliganded subunits of the tetramer through an apparently cooperative mechanism. An NH2-terminal 23,000-dalton fragment generated by S-cyanylation of the cytoplasmic pole of band 3 was approximately 20% as avid in binding aldolase as was native band 3. Several fragments cleaved from the NH2-terminal portion of the 23,000-dalton peptide by trypsin, mild acid hydrolysis, and cyanogen bromide digestion all bound aldolase, while fragments from the rest of the polypeptide were essentially inactive. The first 31 residues of band 3 contained 16 Asp plus Glu, no basic residues, and a blocked alpha-amino terminus. The highly acidic composition of this region is consistent with the strongly electrostatic character of the interaction between band 3 and aldolase, presumably at the strongly basic catalytic center of the enzyme. We conclude that the NH2-terminal region of band 3 bears the membrane-binding site for aldolase.