ULTRASTRUCTURE OF THE RED TIDE DINOFLAGELLATE GYMNODINIUM BREVE. I. GENERAL DESCRIPTION1,2,3

Gymnodimium breve Davis, an unarmored marine dinoflagellate has a cell covering (theca) composed of four membranes. The inner two membranes represent a vesicular layer and in tangential section, the theca appears composed of polygonal areas. Unusual threat ridges are located in the cingular region between the epi- and hypocone. This osmotically sensitive species is extremely vesiculate with dispersed areas of cytoplasm containing typical eukaryotic organelles as well as other organelles found only in dinoflagellates. The non-vesiculated cytoplasm is continuous in serial sections. The chloroplasts can contain either quasi-radial or parallel lamellae typically consisting of three thylakoids each. The pyrenoid is multiple-stalked and lacks a starch cap. The dinophycean pusule is simple and similar to those found in several unarmored marine species. The nucleus is typically dinophycean but the chromosomes appear to lack nonfibrillar material.     

The Potential for Elimination of Racial-Ethnic Disparities in HIV Treatment Initiation in the Medicaid Population among 14 Southern States

Objectives

The purpose of this study was to explore the racial and ethnic disparities in initiation of antiretroviral treatment (ARV treatment or ART) among HIV-infected Medicaid enrollees 18–64 years of age in 14 southern states which have high prevalence of HIV/AIDS and high racial disparities in HIV treatment access and mortality.

Methods

We used Medicaid claims data from 2005 to 2007 for a retrospective cohort study. We compared frequency variances of HIV treatment uptake among persons of different racial- ethnic groups using univariate and multivariate methods. The unadjusted odds ratio was estimated through multinomial logistic regression. The multinomial logistic regression model was repeated with adjustment for multiple covariates.

Results

Of the 23,801 Medicaid enrollees who met criteria for initiation of ARV treatment, only one third (34.6%) received ART consistent with national guideline treatment protocols, and 21.5% received some ARV medication, but with sub-optimal treatment profiles. There was no significant difference in the proportion of people who received ARV treatment between black (35.8%) and non-Hispanic whites (35.7%), but Hispanic/Latino persons (26%) were significantly less likely to receive ARV treatment.

Conclusions

Overall ARV treatment levels for all segments of the population are less than optimal. Among the Medicaid population there are no racial HIV treatment disparities between Black and White persons living with HIV, which suggests the potential relevance of Medicaid to currently uninsured populations, and the potential to achieve similar levels of equality within Medicaid for Hispanic/Latino enrollees and other segments of the Medicaid population.     

The quiet revolution

Sixty years have passed since Avery, MacLeod and McCarty published their landmark paper revealing DNA as the genetic material, writes Heather Dawes.     

Generation of a novel Saccharomyces cerevisiae strain that exhibits strong maltose utilization and hyperosmotic resistance using nonrecombinant techniques

A yeast strain capable of leavening both unsugared and sweet bread dough efficiently would reduce the necessity of carrying out the expensive procedure of producing multiple baker's yeast strains. But issues involving the use of genetically modified foods have rendered the use of recombinant techniques for developing yeast strains controversial. Therefore, we used strong selection and screening systems in conjunction with traditional mass mating techniques to develop a strain of Saccharomyces cerevisiae that efficiently leavens both types of dough.     

The essential and ancillary role of glutathione in Saccharomyces cerevisiae analysed using a grande gsh1 disruptant strain

A grande gsh1 disruptant mutant of Saccharomyces cerevisiae was generated by crossing a petite disruptant to a wild-type grande strain. This strain was relatively stable, but generated petites at an elevated frequency, illustrating the ancillary role of glutathione (GSH) in the maintenance of the genetic integrity of the mitochondrial genome. The availability of the grande gsh1 deletant enabled an evaluation of the role of GSH in the cellular response to hydrogen peroxide independent of the effects of a petite mutation. The mutant strain was more sensitive to hydrogen peroxide than the wild-type strain but was still capable of producing an adaptive stress response to this compound. GSH was found to be essential for growth and sporulation of the yeast, but the intracellular level needed to support growth was at least two orders of magnitude less than that normally present in wild-type cells. This surprising result indicates that there is an essential role for GSH but only very low amounts are needed for growth. This result was also found in anaerobic conditions, thus this essential function does not involve protection from oxidative stress. Suppressors of the gsh1 deletion mutation were isolated by ethylmethanesulfonate mutagenesis. These were the result of a single recessive mutation (sgr1, suppressor for glutathione requirement) that relieved the requirement for GSH for growth on minimal medium but did not affect the sensitivity to H(2)O(2) stress. Interestingly, the gsh1 sgr1 mutant generated petites at a lower rate than the gsh1 mutant. Thus, it is suggested that the essential role of GSH is involved in the maintenance of the mitochondrial genome.     

Effects of methyldopa on prolactin and growth hormone.

The effects of administration of methyldopa on serum prolactin and growth hormone (GH) concentrations in hypertensive patients were studied. Single doses of methyldopa (750 or 1000 mg) significantly increased serum prolactin levels, peak concentrations occurring four to six hours after drug administrations. Long-term methyldopa treatment was associated with threefold to fourfold increases in basal prolactin levels compared with those in normal subjects. In patients treated with methyldopa for two to three weeks the GH response to insulin hypoglycaemia was significantly greater than in normal subjects and untreated hypertensive patients. In contrast, patients treated for prolonged periods (mean 13-4 months) had a GH reponse indistinguishable from normal.     

The regulation of poly-β-hydroxybutyrate metabolism in Azotobacter beijerinckii

1. The enzymes beta-ketothiolase, acetoacetyl-CoA reductase, acetoacetate-succinate CoA-transferase (;thiophorase') and d(-)-3-hydroxybutyrate dehydrogenase have been partially purified from crude extracts of glucose-grown nitrogen-fixing batch cultures of Azotobacter beijerinckii. The condensation of acetyl-CoA to acetoacetyl-CoA catalysed by beta-ketothiolase is inhibited by CoASH, and the reverse reaction is inhibited by acetoacetyl-CoA. Acetoacetyl-CoA reductase has K(m) for acetoacetyl-CoA of 1.8mum and is inhibited by acetoacetyl-CoA above 10mum. The enzyme utilizes either NADH or NADPH as electron donor. The second enzyme of poly-beta-hydroxybutyrate degradation, d(-)-3-hydroxybutyrate dehydrogenase, is NAD(+)-specific and is inhibited by NADH, pyruvate and alpha-oxoglutarate. CoA transferase is inhibited by acetoacetate, the product of hydroxybutyrate oxidation. In continuous cultures poly-beta-hydroxybutyrate biosynthesis ceased on relaxation of oxygen-limitation and the rates in situ of oxygen consumption and carbon dioxide evolution of such cultures increased without a concomitant increase in glucose uptake. 2. On the basis of these and other findings a cyclic mechanism for the biosynthesis and degradation of poly-beta-hydroxybutyrate is proposed, together with a regulatory scheme suggesting that poly-beta-hydroxybutyrate metabolism is controlled by the redox state of the cell and the availability of CoASH, pyruvate and alpha-oxoglutarate. beta-Ketothiolase plays a key role in the regulatory process. Similarities to the pathways of poly-beta-hydroxybutyrate biosynthesis and degradation in Hydrogenomonas are discussed.     

ULTRASTRUCTURAL OBSERVATIONS OF GYRODINIUM ESTUARIALE (DINOPHYCEAE)1

Gyrodinium estuariale Hulburt has ultrastructural features typical for a dinoflagellate including a particularly well developed pusule and numerous prominent trichocysts. The amphiesma is relatively simple with thecal vesicles containing thecal membranes. The epicone is embellished with two concentric raised ridges reminiscent of the form typical for more heavily thecate genera.     

Accumulation of a Polyhydroxyalkanoate Containing Primarily 3-Hydroxydecanoate from Simple Carbohydrate Substrates by Pseudomonas sp. Strain NCIMB 40135

A number of Pseudomonas species have been identified which accumulate a polyhydroxyalkanoate containing mainly 3-hydroxydecanoate monomers from sodium gluconate as the sole carbon source. One of these, Pseudomonas sp. strain NCIMB 40135, was further investigated and shown to accumulate such a polyhydroxyalkanoate from a wide range of carbon sources (C₂ to C₆); however, when supplied with octanoic acid it produced a polyhydroxyalkanoate containing mainly 3-hydroxyoctanoate monomers. Polymer synthesis occurred in batch culture after cessation of growth due to exhaustion of nitrogen. In continuous culture under nitrogen limitation up to 16.9% (wt/wt) polyhydroxyalkanoate was synthesized from glucose as the carbon source. The monomer units are mainly of the R-(−) configuration. Nuclear magnetic resonance studies confirmed the composition of the polymer. Differential scanning calorimetry suggested that the solvent-extracted polymer contained a significant proportion of crystalline material. The weight-average molecular weight of the polymer from glucose-grown cells was 143,000.