Prophylactic and curative effects of Bacopa monniera in gastric ulcer models.

Bacopa monniera Wettst. (BM, syn. Herpestis monniera L; Scrophulariaceae), is an Ayurvedic drug used as a rasayana. Its fresh juice was earlier reported to have significant antiulcerogenic activity. In continuation, methanolic extract of BM (BME) standardized to bacoside-A content (percentage-38.0 ± 0.9), when given in the dose of 10–50 mg/kg, twice daily for 5 days, showed dose-dependent anti-ulcerogenic on various gastric ulcer models induced by ethanol, aspirin, 2 h cold restraint stress and 4 h pylorus ligation. BME in the dose of 20 mg/kg, given for 10 days, twice daily showed healing effects against 50% acetic acid-induced gastric ulcers. Further work was done to investigate the possible mechanisms of its action by studying its effect on various mucosal offensive acid-pepsin secretion and defensive factors like mucin secretion, mucosal cell shedding, cell proliferation and antioxidant activity in rats. BME 20 mg/kg showed no effect on acid-pepsin secretion, increased mucin secretion, while it decreased cell shedding with no effect on cell proliferation. BME showed significant antioxidant effect per se and in stressed animals. Thus, the gastric prophylactic and curative effects of BME may be due to its predominant effect on mucosal defensive factors.     

Studies of the seminal receptacle of the crab Portunus sanguinolentus (Portunidae: Brachyura)

The seminal receptacle or spermatheca of Portunus sanguinolentus consists of two parts--an anterior glandular and a posterior chitinous part. The chitinous part continues as the oviduct, which opens on the sternite of the sixth thoracic segment. Significant morphological and histological differences were observed between the spermatheca, as well as the oviduct, of mated and unmated crabs. In mated crabs the spermatheca is much more bulging, owing to receipt of a copious supply of seminal products, and its cells are hyperactive. Further stages of ovarian development were observed as indicators of sequential changes in the spermatheca. The secretory cells gradually disintegrate by way of holocrine secretion; this results in cellular stratification and the formation of distinct furrows in the chitinous posterior part.     

Observations on the nature of neurosecretion in the marine crab Portunus sanguinolentus (Herbst) (Crustacea: Brachyura)

Several types of NS cells were identified in Portunus sanguinolentus--five types (A, A', B, C and D) in the brain and thoracic ganglion, four types (A, B, C and D) in the commissural ganglia and four types (alpha, beta, gamma and delta) in the optic ganglia. The distribution of these NS cells is described. Cytochemically, the neurosecretory material in the NS cells has a carbohydrate moiety and is rich in disulphide groups, lipids, phospholipids and RNA. It contains a small amount of sulphydryl groups and protein-bound NH2 groups, but no tyrosine or tryptophan. The NS activity of the brain was found to be closely associated with the reproductive and moult cycles. Just before the initiation of vitellogenesis and moulting the NS cells display secretory hyperactivity. Axonal transport of NS material was also observed in the NS cells.     

Enigma Prevents Cbl-c-Mediated Ubiquitination and Degradation of RETMEN2A

The Cbl proteins (Cbl, Cbl-b, and Cbl-c) are a highly conserved family of RING finger ubiquitin ligases (E3s) that function as negative regulators of tyrosine kinases in a wide variety of signal transduction pathways. In this study, we identify a new Cbl-c interacting protein, Enigma (PDLIM7). This interaction is specific to Cbl-c as Enigma fails to bind either of its closely related homologues, Cbl and Cbl-b. The binding between Enigma and Cbl-c is mediated through the LIM domains of Enigma as removal of all three LIM domains abrogates this interaction, while only LIM1 is sufficient for binding. Here we show that Cbl-c binds wild-type and MEN2A isoforms of the receptor tyrosine kinase, RET, and that Cbl-c enhances ubiquitination and degradation of activated RET. Enigma blocks Cbl-c-mediated RETMEN2A ubiquitination and degradation. Cbl-c decreased downstream ERK activation by RETMEN2A and co-expression of Enigma blocked the Cbl-c-mediated decrease in ERK activation. Enigma showed no detectable effect on Cbl-c-mediated ubiquitination of activated EGFR suggesting that this effect is specific to RET. Through mapping studies, we show that Cbl-c and Enigma bind RETMEN2A at different residues. However, binding of Enigma to RETMENA prevents Cbl-c recruitment to RETMEN2A. Consistent with these biochemical data, exploratory analyses of breast cancer patients with high expression of RET suggest that high expression of Cbl-c correlates with a good outcome, and high expression of Enigma correlates with a poor outcome. Together, these data demonstrate that Cbl-c can ubiquitinate and downregulate RETMEN2A and implicate Enigma as a positive regulator of RETMEN2A through blocking of Cbl-mediated ubiquitination and degradation.     

Crystallization and preliminary x-ray investigation of sarcoplasmic calcium-binding protein from Nereis diversicolor

Crystals of sarcoplasmic calcium-binding proteins from Nereis diversicolor have been grown from solutions of ammonium sulfate. The crystals are monoclinic, space group P2(1); the axes are a = 43.65 (1), b = 56.05 (1), c = 65.77 (1) A, and beta = 92.58 (2) degrees. The crystals are quite stable to x-rays and diffract beyond 2.5 A resolution. The asymmetric unit contains two protein molecules.     

The structure of guanosine-thymidine mismatches in B-DNA at 2.5-A resolution

The structure of the deoxyoligomer d(C-G-C-G-A-A-T-T-T-G-C-G) was determined at 2.5-A resolution by single crystal x-ray diffraction techniques. The final R factor is 18% with the location of 71 water molecules. The oligomer crystallizes in a B-DNA-type conformation, with two strands interacting to form a dodecamer duplex. The double helix consists of four A X T and six G X C Watson-Crick base pairs and two G X T mismatches. The G X T pairs adopt a "wobble" structure with the thymine projecting into the major groove and the guanine into the minor groove. The mispairs are accommodated in the normal double helix by small adjustments in the conformation of the sugar phosphate backbone. A comparison with the isomorphous parent compound containing only Watson-Crick base pairs shows that any changes in the structure induced by the presence of G X T mispairs are highly localized. The global conformation of the duplex is conserved. The G X T mismatch has already been studied by x-ray techniques in A and Z helices where similar results were found. The geometry of the mispair is essentially identical in all structures so far examined, irrespective of the DNA conformation. The hydration is also similar with solvent molecules bridging the functional groups of the bases via hydrogen bonds. Hydration may be an important factor in stabilizing G X T mismatches. A characteristic of Watson-Crick paired A X T and G X C bases is the pseudo 2-fold symmetry axis in the plane of the base pairs. The G X T wobble base pair is pronouncedly asymmetric. This asymmetry, coupled with the disposition of functional groups in the major and minor grooves, provides a number of features which may contribute to the recognition of the mismatch by repair enzymes.     

Vigna radiata var.Sublobata (Fabaceae): Economically useful wild relative of urd and mung beans

Eight natural populations ofVigna radiata var.sublobata— wild relative of cultivated urd (V. mungoj and mung (V. radiata,) beans—were sampled from different ecozones of Palney Hills, an eastward offshoot of Western Ghats of Tamilnadu, India. Photosynthetic efficiency, protein content, seed weight, and amino acid composition were determined for it and the cultigens. Some populations ofV. radiata var.sublobata are as good as or even superior to the cultigens. The wild relative is a potential donor of desirable traits to urd and mung beans.     

The stability of oligodeoxyribonucleotide duplexes containing degenerate bases.

Oligodeoxyribonucleotides containing N4-methoxycytosine (mo4C), N4-methoxy-5-methylcytosine (mo4m5C) and other base-analogues were synthesised and used to compare the stabilities of duplexes containing mo4C.A and mo4C.G base pairs with those containing normal and mismatch pairs. The Tm values and other thermodynamic parameters are recorded. The otherwise identical duplexes containing a mo4C.A and a mo4C.G base pair have closely similar stabilities to each other and to the corresponding duplexes containing normal base pairs, considerably greater than the stabilities of those containing mismatch pairs. Corresponding observations are recorded in dot-blot experiments using M13 cloned DNA carrying an insert complementary to the oligonucleotides; approximate Td values are given.     

Purification and Characterization of Soluble (Cytosolic) and Bound (Cell Wall) Isoforms of Invertases in Barley (Hordeum vulgare) Elongating Stem Tissue

Three different isoforms of invertases have been detected in the developing internodes of barley (Hordeum vulgare). Based on substrate specificities, the isoforms have been identified to be invertases (β-fructosidases EC 3.2.1.26). The soluble (cytosolic) invertase isoform can be purified to apparent homogeneity by diethylaminoethyl cellulose, Concanavalin-A Sepharose, organomercurial Sepharose, and Sephacryl S-300 chromatography. A bound (cell wall) invertase isoform can be released by 1 molar salt and purified further by the same procedures as above except omitting the organo-mercurial Sepharose affinity chromatography step. A third isoform of invertase, which is apparently tightly associated with the cell wall, cannot be isolated yet. The soluble and bound invertase isoforms were purified by factors of 60- and 7-fold, respectively. The native enzymes have an apparent molecular weight of 120 kilodaltons as estimated by gel filtration. They have been identified to be dimers under denaturing and nondenaturing conditions. The soluble enzyme has a pH optimum of 5.5, K_m of 12 millimolar, and a V_max of 80 micromole per minute per milligram of protein compared with cell wall isozyme which has a pH optimum of 4.5, K_m of millimolar, and a V_max of 9 micromole per minute per milligram of protein.