The dark-colour-inducing neurohormone of locusts in relation to an albino mutant of Schistocerca gregaria

In the albino mutant of an Okinawa strain of Locusta migratoria (L.) (Orthoptera: Acrididae), albinism is caused by the absence of the dark‐colour‐inducing neurohormone (DCIN), which is present in the corpora cardiaca (CC) of normally coloured phenotypes. This study tests whether the absence of DCIN is responsible for albinism in an albino mutant of another locust, Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae). This seemed feasible because a single Mendelian unit controls albinism in both species. However, implantation of CC, or injection of an extract of CC, from albino donors of S. gregaria, induce dark coloration in crowded nymph recipients of the Okinawa albino mutant of L. migratoria, as effectively as do implanted CC, or injections of extract of CC, from normal phenotype donors of S. gregaria. Therefore, DCIN is present in the albino mutant of S. gregaria, and consequently, the albinism in this mutant is not caused by its absence. Implantation of CC, or injection of extracts of CC, from albino donors of S. gregaria to conspecific albino nymphs does not induce darkening. Only extremely high doses of synthetic DCIN injected into albino nymphs of S. gregaria are effective, inducing some darkening. The dose to induce such darkening in albino nymphs of S. gregaria is 50 nmol, ≈ 5 × 10⁶ times higher than that (10 femtomol) needed to induce equivalent darkening in nymphs of the Okinawa albinos of L. migratoria. The results are discussed and some possible explanations of the observed effects outlined.     

Fungal rhodopsins and opsin-related proteins: eukaryotic homologues of bacteriorhodopsin with unknown functions.

In the last decade, several genome sequencing projects revealed the existence of previously unknown photoreceptors. Among those are eukaryotic rhodopsins of haloarchaeal type, mostly represented by fungal sequences. We have classified and analyzed seventy-seven of these fungal proteins, which show a high similarity of their putative transmembrane regions to those of bacteriorhodopsin. Those sequences can be divided into the two subgroups, fungal rhodopsins (RDs) and opsin-related proteins (ORPs), the latter lacking the lysine residue necessary for retinal binding. We have analyzed the conservation pattern of the residues known to have functional or structural importance in bacteriorhodopsin and discussed dramatic differences in the conservation between RDs and ORPs. We found many cases of multiple forms of RDs and/or ORPs and examined possible reasons for such multiplicity. For some species the reason may lie in functional photobiological diversification, while for the others it follows the pattern of evolutionary recent genome duplication and possible functional redundancy.     

Rotatory dispersion of the β-form of polypeptides

The rotatory dispersion of the β-form of polypeptides is considered. The parameter b₀ of the Moffit-Yang equation is calculated quantum mechanically. The results obtained b₀ = ?30, agrees with experiment which gives b₀ near zero for the β-form.     

Environmental Factors and Admission Rates in Patients with Major Psychiatric Disorders

The aim of this study was to identify environmental factors that might correlate with the admission rate of patients with major psychiatric disorders. During the years 1988-90, 393 consecutive admissions (119 unipolar depressed patients, 211 schizophrenic patients, and 63 bipolar depressed patients) were monitored. Correlations were calculated between the mean daily admission rate for each month and monthly photoperiod, rate of change in photoperiod, mean temperature, mean relative humidity, and mean barometric pressure. It was found that the admission rate of bipolar depressed patients negatively correlated with monthly photoperiod, which means that during winter the admission rate of these patients increased.     

PATTERNS OF PLANT ONTOGENY THAT MAY INFLUENCE GENOMIC STASIS

It is an axiom in biology that genes control the ontogeny and ultimately the final form of an organism. In plants a given morphological form can often arise through more than one ontogenetic pattern of cell divisions. Different ontogenetic patterns have different properties with regard to the final age in cell divisions of the initials in the meristems for a given morphological form. If mutation per genome per cell division is an important biological metric, then since the age of a cell in cell divisions is a function of ontogeny, the cellular ontogeny will influence the degree of mutation-loading in meristematic initials. Thus, ontogeny and form may affect the genes (by promoting or lessening genomic stasis) as well as, of course, being determined by the genes. This paper explores mathematically the relationship between different patterns of cell division and mutation-loading.     

Structural and immunochemical studies on the lipopolysaccharide of the ‘T-antigen’-containing mutant Proteus mirabilis R14/1959

Abstract In DOC-PAGE, lipopolysaccharide (LPS) of Proteus mirabilis R14/1959 (Rb-type) mutant showed a ladder-like migration pattern indicating the presence of a high molecular weight polysaccharide chain. The isolated polysaccharide, called T-antigen because of similarity with the T1 chain of Salmonella friedenau LPS, contained d -glucose, d -galacturonic acid ( d -GalA), and d -GlcNAc in molar ratios 2:1:1 and was structurally different from the O-antigen of the parental S-strain P. mirabilis S1959 but identical to the O-antigen of another S-strain Proteus penneri 42. The importance of a d -GalA( l -Lys)-containing epitope, most likely present in the core region of LPS, and of GalA present in the T-antigen chain in manifesting the serological specificity of P. mirabilis R14/1959 were revealed using rabbit polyclonal homologous and heterologous R- and O-specific antisera and the appropriate antigens, including synthetic antigens which represent partial structures of various Proteus LPS.     

Genetic control and expression of the major ejaculatory bulb protein (PEB-me) inDrosophila melanogaster

PEB-me is a predominant protein of matureDrosophila melanogaster ejaculatory bulbs. It is resolved into four or five closely spaced subfractions (apparent molecular weight 35–39 kD) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Four electrophoretic variants of PEB-me differing in apparent molecular weight by 200–800 daltons were found. These appear to be controlled by four alleles of a gene (peb) located by recombination and deletion mapping to the 60F1-2 region of chromosome 2. A minor ejaculatory bulb protein of ca. 80 kD (hPEB) was found to be immunochemically related to PEB and possibly encoded bypeb. PEB is not detected by immunoblotting techniques in virgin females, in male tissues other than the ejaculatory bulb, or during developmental stages preceding the formation of this organ. The results of transplantations of genital imaginal discs and of immature ejaculatory bulbs between two strains having different PEB alleles suggest that the ejaculatory bulb is the site of PEB synthesis. In flies mutant fortra, tra-2, dsx, orix, tissue specificity of PEB localization is retained and the protein is found whenever the ejaculatory bulb is formed, regardless of the chromosomal sex of the fly. The protein is transferred into the female genital duct during mating, where it can be detected for up to 12 hr. Possible functions of PEB inDrosophila reproduction are discussed.     

Effects of retinoic acid on protein synthesis in cultured melanoma cells

Retinoic acid reduces the growth rate of mouse S91 melanoma cells in culture and increases the proportion of cells in the G₁ phase of the cell cycle. Because of the integral role protein synthesis has been shown to play in growth control we studied the effect of retinoic acid on the protein synthesis machinery with a cell-free system developed from the melanoma cells. This system was capable of translating endogenous mRNA, exogenous globin mRNA, and the synthetic template poly(U). Of the above activities of the protein synthesis system only the translation of endogenous mRNA was reduced significantly in the cell-free system prepared from retinoic acid-treated cells. Analyses of the amount and function of RNA revealed that treatment with retinoic acid leads to reductions in total RNA content, in the proportion of ribosomes in polysomes, in the amount of poly(A)RNA, and in the amount of polysome-associated mRNA. All these effects of retinoic acid contribute to the decrease in protein synthesis activity of treated cells. Two-dimensional electrophoresis anlaysis of L-[³⁵S]methionine-labeled proteins produced by untreated and treated cells revealed only a few quantitative differences. We suggest that retinoic acid-induced suppression of protein synthesis activity may be the cause for growth inhibition.     

Expression of the recombinant antibacterial peptide sarcotoxin IA in Escherichia coli cells

Sarcotoxin IA is an antibacterial peptide that is secreted by a meat-fly Sarcophaga peregrina larva in response to a hypodermic injury or bacterial infection. This peptide is highly toxic against a broad spectrum of both Gram-positive and Gram-negative bacteria and lethal to microbes even at nanomolar concentrations. However, research needs as well as its potential use in medicine require substantial amounts of highly purified sarcotoxin. Because heterologous expression systems proved to be inefficient due to sarcotoxin sensitivity to intracellular proteases, here we propose the biosynthesis of sarcotoxin precursors in Escherichia coli cells that are highly sensitive to the mature peptide. To optimize its biosynthesis, sarcotoxin was translationally fused with proteins highly expressed in E. coli. A fusion partner and the position of sarcotoxin in the chimeric polypeptide were crucial for protecting the sarcotoxin portion of the fusion protein from proteolysis. Released after chemical cleavage of the fusion protein and purified to homogeneity, sarcotoxin displayed antibacterial activity comparable to that previously reported for the natural peptide.