Origins and evolution of AIDS viruses: estimating the time-scale

The primate lentiviruses comprise SIV strains from various host species, as well as two viruses, HIV-1 and HIV-2, that cause AIDS in humans. The origins of HIV-1 and HIV-2 have been traced to cross-species transmissions from chimpanzees and sooty mangabey monkeys respectively. Two approaches have been taken to estimate the time-scale of the evolution of these viruses. Certain groups of SIV strains appear to have evolved in a host-dependent manner, implying a time-scale of many thousands or even millions of years. In stark contrast, molecular clock calculations have previously been used to estimate a time-scale of only tens or hundreds of years. Those calculations largely ignored heterogeneity of evolutionary rates across different sites within sequences. In fact, the distribution of rates at different sites seems extremely skewed in HIV-1, and so the time-depth of the primate lentivirus evolutionary tree may have been underestimated by at least a factor of ten. However, these date estimates still seem to be far too recent to be consistent with host-dependent evolution.     

Overexpression of secretory phospholipase A(2) causes rapid catabolism and altered tissue uptake of high density lipoprotein cholesteryl ester and apolipoprotein A-I

Plasma levels of high density lipoprotein (HDL) cholesterol and its major protein component apolipoprotein (apo) A-I are significantly reduced in both acute and chronic inflammatory conditions, but the basis for this phenomenon is not well understood. We hypothesized that secretory phospholipase A(2) (sPLA(2)), an acute phase protein that has been found in association with HDL, promotes HDL catabolism. A series of HDL metabolic studies were performed in transgenic mice that specifically overexpress human sPLA(2) but have no evidence of local or systemic inflammation. We found that HDL isolated from these mice have a significantly lower phospholipid and cholesteryl ester and significantly greater triglyceride content. The fractional catabolic rate (FCR) of (125)I-HDL was significantly faster in sPLA(2) transgenic mice (4.08 +/- 0.01 pools/day) compared with control wild-type littermates (2.16 +/- 0.48 pools/day). (125)I-HDL isolated from sPLA(2) transgenic mice was catabolized significantly faster than (131)I-HDL isolated from wild-type mice after injection in wild-type mice (p < 0.001). Injection of (125)I-tyramine-cellobiose-HDL demonstrated significantly greater degradation of HDL apolipoproteins in the kidneys of sPLA(2) transgenic mice compared with control mice (p < 0.05). The fractional catabolic rate of [(3)H]cholesteryl ether HDL was significantly faster in sPLA(2)-overexpressing mice (6.48 +/- 0.24 pools/day) compared with controls (4.80 +/- 0.72 pools/day). Uptake of [(3)H] cholesteryl ether into the livers and adrenals of sPLA(2) transgenic mice was significantly enhanced compared with control mice. In summary, these data demonstrate that overexpression of sPLA(2) alone in the absence of inflammation causes profound alterations of HDL metabolism in vivo and are consistent with the hypothesis that sPLA(2) may promote HDL catabolism in acute and chronic inflammatory conditions.     

Preparation and characterization of 'heparinocytes': erythrocytes with covalently bound low molecular weight heparin

In an attempt to create the possibility of stable, long acting, intravascular anticoagulation, low molecular weight heparin was modified by introducing a sulfhydryl group into the molecule (LMWH-SH). Human erythrocytes were covalently grafted with LMWH-SH by the use of a heterobifunctional coupling reagent which reacts with the SH group of LMWH-SH and surface exposed amino groups of erythrocytes now called 'heparinocytes' (HC). HC were morphologically indistinguishable from untreated erythrocytes and displayed identical osmotic resistance. The functionality of HC was analyzed by classical coagulation tests in which they dose dependently inhibited clot formation. HC were also functional in recalcified whole blood inhibiting thrombin formation as assessed by the cleavage of the chromogenic substrate S-2238. The system appears applicable as a potential autologous, long-term anticoagulant treatment or prophylaxis.     

Wide range of viral load in healthy african green monkeys naturally infected with simian immunodeficiency virus

The distribution and levels of simian immunodeficiency virus (SIV) in tissues and plasma were assessed in naturally infected African green monkeys (AGM) of the vervet subspecies (Chlorocebus pygerythrus) by limiting-dilution coculture, quantitative PCR for viral DNA and RNA, and in situ hybridization for SIV expression in tissues. A wide range of SIV RNA levels in plasma was observed among these animals (<1,000 to 800,000 copies per ml), and the levels appeared to be stable over long periods of time. The relative numbers of SIV-expressing cells in tissues of two monkeys correlated with the extent of plasma viremia. SIV expression was observed in lymphoid tissues and was not associated with immunopathology. Virus-expressing cells were observed in the lamina propria and lymphoid tissue of the gastrointestinal tract, as well as within alveolar macrophages in the lung tissue of one AGM. The range of plasma viremia in naturally infected AGM was greater than that reported in naturally infected sooty mangabeys. However, the degree of viremia in some AGM was similar to that observed during progression to AIDS in human immunodeficiency virus-infected individuals. Therefore, containment of viremia is an unlikely explanation for the lack of pathogenicity of SIVagm in its natural host species, AGM.     

Microsensors as a tool to determine chemical microgradients and bacterial activity in wastewater biofilms and flocs

Microsensors used in microbial ecology are reviewed with emphasis on new sensor developments (NO₃ ^-, NO₂ ^-, NH₄ ⁺, CO₂, H₂, H₂S and CH₄ microsensors as well as fiberoptical microsensors for O₂, temperature and pH). Examples of microsensor applications in biofilms and activated sludge flocs are presented, where sulfate reduction and denitrification were studied.     

Production of polyhydroxybutyrate by Ralstonia eutropha from protein hydrolysates

Polyhydroxybutyrate (PHB) was produced by Ralstonia eutropha DSM 11348 (formerly Alicaligenes eutrophus) in media containing 20–30 g l⁻¹ casein peptone or casamino acids as sole sources of nitrogen. In fermentations using media based on casein peptone, permanent growth up to a cell dry mass of 65 g l⁻¹ was observed. PHB accumulated in cells up to 60%–80% of dry weight. The lowest yields were found in media without any trace elements or with casamino acids added only. The residual cell dry masses were limited to 10–15 g l⁻¹ and did not contain PHB. The highest productivity amounted to 1.2 g PHB l⁻¹ h⁻¹. The mean molecular mass of the biopolymer was determined as 750 kDa. The proportion of polyhydroxyvalerate was less than 0.2% in PHB. The bioprocess was scaled up to a 300-l plant. During a fermentation time of 39 h the cells accumulated PHB to 78% w/w. The productivity was 0.98 g PHB l⁻¹ h¹. Received: 8 July 1998 / Accepted: 26 August 1998     

Impaired Glucose Tolerance or Newly Diagnosed Diabetes Mellitus Diagnosed during Admission Adversely Affects Prognosis after Myocardial Infarction: An Observational Study

Objective

To investigate the prognostic effect of newly diagnosed diabetes mellitus (NDM) and impaired glucose tolerance (IGT) post myocardial infarction (MI).

Research Design and Methods

Retrospective cohort study of 768 patients without preexisting diabetes mellitus post-MI at one centre in Yorkshire between November 2005 and October 2008. Patients were categorised as normal glucose tolerance (NGT n = 337), IGT (n = 279) and NDM (n = 152) on pre- discharge oral glucose tolerance test (OGTT). Primary end-point was the first occurrence of major adverse cardiovascular events (MACE) including cardiovascular death, non-fatal MI, severe heart failure (HF) or non-haemorrhagic stroke. Secondary end-points were all cause mortality and individual components of MACE.

Results

Prevalence of NGT, impaired fasting glucose (IFG), IGT and NDM changed from 90%, 6%, 0% and 4% on fasting plasma glucose (FPG) to 43%, 1%, 36% and 20% respectively after OGTT. 102 deaths from all causes (79 as first events of which 46 were cardiovascular), 95 non fatal MI, 18 HF and 9 non haemorrhagic strokes occurred during 47.2 ± 9.4 months follow up. Event free survival was lower in IGT and NDM groups. IGT (HR 1.54, 95% CI: 1.06–2.24, p = 0.024) and NDM (HR 2.15, 95% CI: 1.42–3.24, p = 0.003) independently predicted MACE free survival. IGT and NDM also independently predicted incidence of MACE. NDM but not IGT increased the risk of secondary end-points.

Conclusion

Presence of IGT and NDM in patients presenting post-MI, identified using OGTT, is associated with increased incidence of MACE and is associated with adverse outcomes despite adequate secondary prevention.     

Ophiostomatoid fungi including two new fungal species associated with pine root-feeding beetles in northern Spain

Many bark beetles live in a symbiosis with ophiostomatoid fungi but very little is known regarding these fungi in Spain. In this study, we considered the fungi associated with nine bark beetle species and one weevil infesting two native tree species (Pinus sylvestris and Pinus nigra) and one non-native (Pinus radiata) in Cantabria (Northern Spain). This included examination of 239 bark beetles or their galleries. Isolations yielded a total of 110 cultures that included 11 fungal species (five species of Leptographium sensu lato including Leptographium absconditum sp. nov., five species of Ophiostoma sensu lato including Ophiostoma cantabriense sp. nov, and one species of Graphilbum). The most commonly encountered fungal associates of the bark beetles were Grosmannia olivacea, Leptographium procerum, and Ophiostoma canum. The aggressiveness of the collected fungal species was evaluated using inoculations on two-year-old P. radiata seedlings. Leptographium wingfieldii, Leptographium guttulatum, and Ophiostoma ips were the only species capable of causing significant lesions.     

<Emphasis Type="Italic">Ophiostoma tsotsi</Emphasis> sp. nov., A Wound-infesting Fungus of Hardwood Trees in Africa

Polymorphic sequence-characterised marker assays from a recent diversity study on the Ascomycete fungus Ophiostoma quercus reported that some isolates from Africa were genetically distinct from O. quercus. In the present study, these African isolates were compared with authentic O. quercus isolates by evaluating morphological characters, growth in culture, mating compatibility and DNA sequence data. The isolates from Africa were morphologically similar to O. quercus, presenting Pesotum and Sporothrix synanamorphs in culture. Phylogenetic analyses of the ribosomal internal transcribed spacer regions 1 and 2, β-tubulin and translation elongation factor 1-α gene regions confirmed that the African group represents a distinct species within the hardwood lineage of the O. piceae complex, closely related to O. ulmi and O. himal-ulmi. Mating studies between O. quercus and the African isolates showed that isolates mated predominantly with those of their own group, although there were rare cases of fertile crosses between the groups. Isolates residing in the African lineage are described here as a new species, O. tsotsi sp. nov.