Antagonism of diazepam-induced feeding in rats by antisera to opioid peptides

Diazepam-induced feeding in rats is antagonized not only by the opiate antagonist naloxone but also intraventricular administration of specific antisera to the endogenous opioid peptides met-enkephalin or beta-endorphin. Pituitary beta-endorphin is probably not implicated in the diazepam effect since blockade with the glucocorticoid dexamethasone of the release of beta-endorphin from the anterior pituitary does not modify the diazepam-induced feeding, which is however prevented by TRH, a suggested physiological antagonist of some of the effects of opioid peptides. The possible central participation of both beta-endorphin and met-enkephalin in the ingestive behavior induced by diazepam gives further support to the postulated physiological role of endogenous opioids in appetite regulation.     

Addition of an androgen-free epididymal protein extract increases the ability of immature hamster spermatozoa to fertilize in vivo and in vitro

The fertility of spermatozoa from the different epididymal segments of hamsters was tested by in-vivo insemination. Caput and proximal corpus spermatozoa were non-fertile; spermatozoa from the distal corpus epididymidis fertilized 13% (38/290) oocytes and those from the proximal and distal cauda epididymidis 71 and 87%, respectively. When tested by in-vitro insemination, distal corpus spermatozoa penetrated 44% of oocytes while those from the distal cauda fertilized 87% of oocytes. Spermatozoa from the distal corpus recovered in Medium BMOC fertilized 13% (28/219) of oocytes in vivo, while those mixed with an epididymal protein preparation (0.8 mg protein/ml) fertilized 24% (49/204; P less than 0.01) of oocytes. When distal corpus spermatozoa were inseminated in vivo with 0.8 mg epididymal protein preparation 34% (31/90) oocytes were fertilized and only 22% (23/103; P less than 0.05) oocytes were fertilized when the proteins were obtained from epididymides of animals castrated for 30 days. When distal corpus spermatozoa were preincubated for 5 h in medium without (control) or with protein preparation (0.8 or 1.6 mg protein/ml), a significant increase in in-vitro oocyte penetration was found (25 compared with 45%; P less than 0.05) when the protein was present at 1.6 mg/ml. These results confirm and extend previous observations suggesting a role for androgen-dependent glycoproteins secreted by the epididymis in the acquisition of fertilizing ability that occurs during sperm maturation.     

Physical structure and genetic expression of the sulfonamide-resistance plasmid pLS80 and its derivatives in Streptococcus pneumoniae and Bacillus subtilis

Summary The 10-kb chromosomal fragment of Streptococus pneumoniae cloned in pLS80 contains the sul-d allele of the pneumococcal gene for dihydropteroate synthase. As a single copy in the chromosome this allele confers resistance to sulfanilamide at 0.2 mg/ml; in the multicopy plasmid it confers resistance to 2.0 mg/ml. The sul-d mutation was mapped by restriction analysis to a 0.4-kb region. By the mechanism of chromosomal facilitation, in which the chromosome restores information to an entering plasmid fragment, a BamHI fragment missing the sul-d region of pLS80 established the full-sized plasmid, but with the sul-s allele of the recipient chromosome.A spontaneous deletion beginning 1.5 kb to the right of the sul-d mutation prevented gene function, possibly by removing a promoter. This region could be restored by chromosomal facilitation and be demonstrated in the plasmid by selection for sulfonamide resistance. Under selection for a vector marker, tetracycline resistance, only the deleted plasmid was detectable, apparently as a result of plasmid segregation and the advantageous growth rates of cells with smaller plasmids. When such cells were selected for sulfonamide resistance, the deleted region returned to the plasmid, presumably by equilibration between the chromosome and the plasmid pool, to give a low frequency (10^-3) of cells resistant to sulfanilamide at 2.0 mg/ml. Models for the mechanisms of chromosomal facilitation and equilibration are proposed.Several derivatives of pLS80 could be transferred to Bacillus subtilis, where they conferred resistance to sulfanil-amide at 2 mg/ml, thereby demonstrating cross-species expression of the pneumococcal gene. Transfer of the plasmids to B. subtilis gave rise to large deletions to the left of the sul-d marker, but these deletions did not interfere with the sul-d gene function. Restriction maps of pLS80 and its variously deleted derivatives are presented.     

Phylogenetic relationships in theSideritis leucantha group (Lamiaceae)

Six closely related taxa of the sect.Eusideritis of the genusSideritis (S. leucantha, S. pusilla, S. flavovirens, S. granatensis, S. biflora andS. osteoxylla) are analysed to elucidate their phylogenetic relationships and position within the sect.Eusideritis. Meiotic behaviour, karyotype features, size and fertility of pollen grains, DNA amounts and seed protein profiles are reviewed. A polyploid origin of the group (from x = 7) and the further diversification through dysploidy and chromosome repatterning is postulated.S. osteoxylla is apparently of hybrid origin.     

A new function for overall optimization of yeast production

The influence of several operating variables on the productivity and nutritional quality of Candida utilis under carbon-limited growth conditions was studied. Four responses were analyzed: biomass yield (Y), in vitro dry matter digestibility (d), nucleic acid cotents, and protein content (P). Three operating variables were studied: dilution rate, temperature, and carbon-nitrogen ratio in the growth medium. Correlation describing the influence of operating variables on the studied response parameters were developed. From these correlations response surfaces were drawn. A new function, alpha = PdY, is proposed as a more comprehensive criterion for selecting the optimal conditions under the constraint of satisfying multiple objectives. It is demonstrated to be superior to the yield coefficient alone in this respect, since it accounts for factors that are important to the nutritional aspects of the process.     

Regulatory interaction of photosynthetic nitrate utilization and carbon dioxide fixation in the cyanobacterium Anacystis nidulans

The rate of photosynthetic nitrate utilization in Anacystis nidulans is strongly influenced by the availability of carbon dioxide. This dependence can be relieved by inhibiting the metabolism of the ammonium derived from nitrate reduction. Nitrate uptake seems to be modulated through a sensitive regulatory system integrating the photosynthetic metabolism of carbon and nitrogen, with CO₂ fixation products antagonizing the inhibitory effect of ammonium derivatives.     

Desangeloylshairidin,X-ray structure determination of a sesquiterpene lactone from Guillonea scabra

The structure and absolute configuration of desangeloylshairidin, a guaianolide isolated from Guillonea scabra, have been established by X-ray diffraction analysis. No conformational change was observed in its seven-membered ring between the crystal and deuterochloroform solution states.     

Heritable fragile sites on human chromosomes. X. New folate-sensitive fragile sites: 6p23, 9p21, 9q32, and 11q23

Four new folate-sensitive fragile sites are documented at 6p23, 9p21, 9q32, and 11q23. These have all been shown to be heritable except for the one at 9p21, which has been seen only in a single individual. As with the other autosomal fragile sites, these appear to be innocuous in heterozygotes.