High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans

We compared male-reproductive-tract polypeptides of Drosophila melanogaster and D. simulans by using two-dimensional gel electrophoresis. Approximately 64% of male-reproductive-tract polypeptides were identical between two randomly chosen isofemale lines from these two species, compared with 83% identity for third-instar imaginal wing-disc polypeptides. Qualitatively similar differences were found between reproductive tracts and imaginal discs when D. sechellia was compared with D. melanogaster and with D. simulans. When genic polymorphism was taken into account, approximately 10% of male- reproductive-tract polypeptides were apparently fixed for different alleles between D. melanogaster and D. simulans; this proportion is the same as that found for soluble enzymes by one-dimensional gel electrophoresis. Strikingly, approximately 20% of male-reproductive- tract polypeptides of either D. melanogaster or D. simulans had no detectable homologue in the other species. We propose that proteins of the Drosophila male reproductive tract may have diverged more extensively between species than have other types of proteins and that much of this divergence may involve large changes in levels of polypeptide expression.      

Ammonium-nitrogen metabolism and nitrogen fixation in azotobacter vinelandii

The probable effect of increasing levels of ammonium nitrogen on the growth, efficiency of nitrogen fixation, and main cellular constituents of Azotobacter vinelandii was studied under shaking and static culture conditions. The presence of NH₄⁺-N up to 50 mgl^-1 level has no harmful effect on the multiplication as well as the yield efficiency ratio of the tested organism. A. vinelandii was able to fix dinitrogen in the presence of NH₄⁺-N when both nitrogen sources were available in the culturing medium. The efficiency of nitrogen fixation was affected by the initial presence of NH₄⁺-N in the medium, it was quite low at the highest level. The crude protein efficiency ratio was correlated inversely with the initial NH₄⁺-N concentration, whereas the total carbohydrate efficiency ratio as well as the total lipid efficiency ratio were positively correlated with the NH₄⁺-N concentration. The presence of NH₄⁺-N in the culturing medium has no essential influence on the qualitative composition of the amino acids in the Azotobacter cells.     

Synthesis of [17,18-3H] trans-13-azaprostanoic acid. A labeled probe for the PGH2/TXA2 receptor

Because of its highly unstable nature, TXA2, produced by platelet metabolism of arachidonic acid, does not lend itself to use as a receptor probe for its own receptor. As such, the stable TXA2/PGH2 antagonist, trans-13-azaprostanoic acid (trans-13-APA, 12b), was prepared as the [17, 18 3H] derivative [( 3H] trans-13-APA, 12c) to study this receptor and to better evaluate the mechanism of action of these azaprostanoids. Tritiated trans-13-APA, 12c, was prepared in nearly theoretical specific activity (57 Ci/mmole) from (17Z)-trans-13-azaprost-17-enoic acid (11b) by catalytic tritiation. The unsaturated 11b was prepared by condensation of cis-7-amino-3-heptene (8) with 2-(6-carboxyhexyl) cyclopentanone (9), NaBH4 reduction, chromatography, and hydrolysis of the trans isomer so isolated. The olefins 11a and b were also of biochemical interest because of the unsaturation in the lower side chain. The presence of similar unsaturation in PGH3(4) and TXA3 (3) renders these prostaglandins inactive as proaggregatory agents. Evaluation of the antiaggregatory activity of 11a and b indicated it to be about the same potency in inhibiting human platelet aggregation as the parent cis and trans-13-APAs, suggesting that introduction of a double bond at the 17 position in platelet prostaglandin antagonists is unlikely to result in enhanced antiplatelet activity.     

Pre-induction priming of the uterine cervix with oral prostaglandin E2 and a placebo

A double blind study was undertaken to determine the effectiveness or oral prostaglandin E2 as a means of improving the pelvic score prior to induction of labour. 48 patients who were greater than 37 were gestation and who had Bishop scores of less than 6 entered the study. Ten tablets were given on an hourly regime. Of 25 patients in the prostaglandin group, 17 were considered successes (68.0%), whereas of 23 patients who received a placebo, 9 were successes (39.1%). No adverse effects were recorded. Prostaglandin E2 is therefore considered a safe and effective method for priming the unfavourable cervix prior to induction of labour.     

Monoclonal antibodies to rabbit liver cytochrome P-448

Cytochrome P-448 (mol wt 55,000 Daltons) from rabbit liver was purified to a specific content of 16.6 nmol/mg. Mice were immunised with this preparation, their spleens removed and dissociated lymphocytes hybridised with myeloma cells. Four monoclonal antibodies against cytochrome P-448 were raised and partially characterised. All four antibodies interacted with cytochrome P-448 in intact microsomal fractions and selectively immunoadsorbed cytochrome P-448 from solubilised microsomal preparations. One of the antibodies inhibited benzo[a] pyrene hydroxylase activity in a reconstituted system, one had no effect on activity and two increased activity. The possible applications of such antibodies are discussed.     

Niche differentiation among clones in asexual grass thrips

Many asexual animal populations comprise a mixture of genetically different lineages, but to what degree this genetic diversity leads to ecological differences remains often unknown. Here, we test whether genetically different clonal lineages of Aptinothrips grass thrips differ in performance on a range of plants used as hosts in natural populations. We find a clear clone‐by‐plant species interactive effect on reproductive output, meaning that clonal lineages perform differently on different plant species and thus are characterized by disparate ecological niches. This implies that local clonal diversities can be driven and maintained by frequency‐dependent selection and that resource heterogeneity can generate diverse clone assemblies.     

Characterization of Streptococcus bovis from the rumen of the dromedary camel and Rusa deer

AIMS: Isolation and characterization of Streptococcus bovis from the dromedary camel and Rusa deer. METHODS AND RESULTS: Bacteria were isolated from the rumen contents of four camels and two deer fed lucerne hay by culturing on the semi-selective medium MRS agar. Based on Gram morphology and RFLP analysis seven isolates, MPR1, MPR2, MPR3, MPR4, MPR5, RD09 and RD11 were selected and putatively identified as Streptococcus. The identity of these isolates was later confirmed by comparative DNA sequence analysis of the 16S rRNA gene with the homologous sequence from S. bovis strains, JB1, C14b1, NCFB2476, SbR1, SbR7 and Sb5, from cattle and sheep, and the Streptococcus equinus strain NCD01037T. The percentage similarity amongst all strains was >99%, confirming the identification of the camel isolates as S. bovis. The strains were further characterized by their ability to utilize a range of carbohydrates, the production of volatile fatty acids (VFA) and lactate and the determination of the doubling time in basal medium 10 supplemented with glucose. All the isolates produced l-lactate as a major fermentation end product, while four of five camel isolates produced VFA. The range of carbohydrates utilized by all the strains tested, including those from cattle and sheep were identical, except that all camel isolates and the deer isolate RD11 were additionally able to utilize arabinose. CONCLUSIONS: Streptococcus bovis was successfully isolated from the rumen of camels and deer, and shown by molecular and biochemical characterization to be almost identical to S. bovis isolates from cattle and sheep. SIGNIFICANCE AND IMPACT OF THE STUDY: Streptococcus bovis is considered a key lactic acid producing bacterium from the gastrointestinal tract of ruminants, and has been implicated as a causative agent of lactic acidosis. This study is the first report of the isolation and characterization of S. bovis from the dromedary camel and Rusa deer, and suggests a major contributive role of this bacterium to fermentative acidosis.     

Growth of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in a long spiral form does not alter expression of immunodominant proteins

Background  

We have previously reported that altered culture conditions (a broth media with shaking) could induce a strain of Helicobacter pylori to assume a long spiral morphology resembling that described for Helicobacter heilmannii. The present study was initiated to determine if other strains of H. pylori could be induced to assume that morphology and if doing so would alter the expression of immunodominant proteins.