Studies onMadhuca butyraceae seed proteins

DefattedMadhuca butyraceae seeds contain 24% of crude protein and 10.4% of saponins. The solubility ofMadhuca seed proteins was determined in water and NaCl as a function of pH and minimum solubility occurred at pH 4.0. The proteins consist of three components with S_20,w values of 2.2, 9.8 and 15.4. On gel filtration the proteins gave three peaks and on diethylaminoethyl cellulose chromatography they resolved into two components. Thein vitro digestibility ofMadhuca seed protein was found to be 69% when assayed with a pepsin-pancreatin system.     

Aqueduct Occlusion Does Not Impair Feeding Induced by Either Third or Fourth Ventricle Galanin Injection

Exogenous galanin stimulates feeding when injected into forebrain and hindbrain sites, including the third and fourth ventricles (3V and 4V), amygdala, paraventricular nucleus of the hypothalamus (PVN), and nucleus of the solitary tract (NTS). Because the PVN and NTS border the ventricular space, it is possible that feeding stimulated by injection of galanin at these sites may be caused by the transport of galanin through the ventricular system to a remote site of action. The role of ventricular transport of galanin between the 3V and 4V in galanin-induced feeding was examined in this study. Rats were implanted with two guide cannula assemblies: one dorsal to the mesencephalic aqueduct and the other in the 3V or 4V. Feeding in response to 3V or 4V galanin injection was first measured after sham-occlusion of the aqueduct. Subsequently, flow of cerebrospinal fluid between the forebrain and hindbrain ventricles was acutely interrupted by injection of a silicone grease plug into the mesencephalic aqueduct just before assessment of the feeding response to 4V or 3V galanin injection. Aqueduct occlusion did not alter the feeding induced by either 3V or 4V galanin injection, indicating that galanin terminals in both the diencephalon and hindbrain are involved in control of food intake.     

Neocarzinostatin abstracts a hydrogen during formation of nucleotide 5'-aldehyde on DNA

The oxidative reaction of polydeoxyadenylic-deoxythymidylic acid [poly(dA-dT)] with neocarzinostatin that produces 5'-thymidine aldehyde esterified to the 5'-end of strand breaks proceeds with hydrogen abstraction. The abstracted hydrogen is covalently bound to the non-protein component of neocarzinostatin; only a small amount (5%) is washed out into solvent. These data rule out a peroxyl radical as the primary DNA damaging species involved in the production of the 5'-aldehyde group. In contrast to earlier reports, it is demonstrated that alpha-tocopherol is not an inhibitor of the reaction.     

Sequence heterogeneity and anomalous electrophoretic mobility of kinetoplast minicircle DNA from Leishmania tarentolae

Several unit-length minicircles from the kinetoplast DNA of Leishmania tarentolae were cloned into pBR322 and into M13 phage vectors. The complete nucleotide sequences of three different partially homologous minicircles were obtained. The molecules contained a region of approx. 80% sequence homology extending for 160–270 bp and a region unique to each minicircle. A 14-mer was found to be conserved in all kinetoplast minicircle sequences reported to date. The frequency distributions of various minicircle sequence classes in L. tarentolae were obtained by quantitative gel electrophoresis and by examination of the “T ladder” patterns of minicircles randomly cloned into M13 at several sites. By these methods we could assign approx. 50% of the total minicircle DNA into a minimum of five sequence classes. A sequence-dependent polyacrylamide gel migration abnormality was observed with several minicircle fragments both cloned and uncloned. The abnormality was dependent on the presence of a portion of the conserved region of the minicircle.     

GRF-induced feeding: Evidence for protein selectivity and opiate involvement

Growth hormone-releasing factor (GRF) is a hypothalamic peptide named for its ability to induce release of growth hormone from the anterior pituitary. GRF also acts as a neurotransmitter in the suprachiasmatic nucleus/medial preoptic area (SCN/MPOA) to stimulate food intake. The purpose of this series of experiments was to explore the nature of GRF-induced feeding, with a particular emphasis on macronutrient selectivity, and to examine the role of opiate activity in the paraventricular nucleus of the hypothalamus (PVN). Chow intake stimulated by GRF microinjection (1 pmol/0.5 μl) into the SCN/MPOA was blocked by injection of methyl-naltrexone (3 μg/0.5 μl) into the PVN. In animals habituated to macronutrient diets (Teklad, WI), GRF preferentially stimulated intake of protein at 2 and 4 h postinjection, whereas it had no effect on carbohydrate intake. Further, this effect was blocked by injection of naloxone (40 nmol/0.5 μl) into the PVN. Microinjection of morphine (0, 1, 10, and 17 μg/0.5 μl) into the PVN also specifically stimulated protein intake at 2 and 4 h postinjection. These results suggest that feeding derived from GRF actions in the SCN/MPOA is macronutrient selective, and is dependent on PVN opiate activity for expression.     

Diagnostic Measures of Influence for s2

We present three intuitive diagnostic measures for judging the influence that single or multiple observations exert on the estimate s², the mean square error. The three measures are shown to be equivalent statistics. We discuss distributional properties of these measures and conclude with an example.     

Protein diffusion in crowded electrolyte solutions

We report on a combined cold neutron backscattering and spin-echo study of the short-range and long-range nanosecond diffusion of the model globular protein bovine serum albumin (BSA) in aqueous solution as a function of protein concentration and NaCl salt concentration. Complementary small angle X-ray scattering data are used to obtain information on the correlations of the proteins in solution. Particular emphasis is put on the effect of crowding, i.e. conditions under which the proteins cannot be considered as objects independent of each other. We thus address the question at which concentration this crowding starts to influence the static and in particular also the dynamical behaviour. We also briefly discuss qualitatively which charge effects, i.e. effects due to the interplay of charged molecules in an electrolyte solution, may be anticipated. Both the issue of crowding as well as that of charge effects are particularly relevant for proteins and their function under physiological conditions, where the protein volume fraction can be up to approximately 40% and salt ions are ubiquitous. The interpretation of the data is put in the context of existing studies on related systems and of existing theoretical models.