Factors Influencing the Production of H and M Antigens by Histoplasma capsulatum: Effect of Physical Factors and Composition of Medium

Stagnant culture methods have permitted only limited physiological studies of the production of H and M antigens by Histoplasma capsulatum because, with such methods, antigen production is uncontrolled. In this investigation, a shake culture method was used to convert yeast-phase inoculum to mycelialphase growth at 25 C. Results strongly suggest that the release of H and M antigens relates to autolysis of the cells. Among the factors influencing production of H and M antigens under shaking conditions, choice of strain was the most important. Alterations of carbon or nitrogen source or variations in amino acid to carbohydrate ratios had limited influence on antigen production. With a strain that produced both H and M antigens, however, proportions of titers of M to H antigens could be made to vary considerably by changes in the medium, the pH, and the temperature. Results suggest that the source of M antigen during autolysis is enzymatic dissolution of the cell wall. The source of H antigen is more obscure. Production of both antigens may be differentially controlled under conditions of good reproducibility by a correct choice of strain and manipulation of culture medium.     

Ground wētā in vines of the Awatere Valley,Marlborough: biology,density and distribution

The endemic New Zealand ground wētā (Hemiandrus sp. ‘promontorius’) has a Naturally Uncommon conservation status. This is because of the paucity of information on its density and distribution. Here, the biology, density and distribution of a population of this wētā found in and around vineyards in the Awatere Valley, Marlborough was studied. Wētā density was assessed in vineyards, paddocks and shrublands in this valley. Soil moisture, penetration resistance, pH and organic matter were recorded at locations with and without wētā. Wētā density in vineyards was significantly higher than in either paddocks or shrub habitats. In vineyards, the density of this insect was significantly higher under-vines than in the inter-rows. Higher numbers of this wētā were found in moist soils that required lower force to burrow. Females laid an average of 55 eggs between March and April, which hatched in September. These findings highlight the intersection between agriculture and conservation.     

Fine‐scale habitat use in Indo‐Pacific humpback dolphins,Sousa chinensis,may be more influenced by fish rather than vessels in the Pearl River Estuary,China

Shifts in habitat use and distribution patterns in dolphins are often concerns that can result from habitat degradation. We investigated how potential changes to a habitat from human activity may alter dolphin distributions within Lingding Bay in the Pearl River Estuary, China, by studying the relationship between fish choruses, vessel presence and Indo‐Pacific humpback dolphin (Sousa chinensis) detection rates. Analyses revealed temporal and spatial variation within fish choruses, vessel presence and dolphin detection rates. After accounting for any temporal autocorrelation, correlations between fish choruses and dolphin detection rates were also found; however, no relationship between fish choruses and vessel presence or dolphin detection rates and vessel presence were observed. Furthermore, fewer dolphins were detected at sites where fish activity was less intense. Thus fish activity, rather than vessels, may be a key factor influencing the distribution of the dolphins within the estuary. These findings emphasize the risk of potential shifts in habitat use for Indo‐Pacific humpback dolphins due to detrimental changes to prey availability and dolphin feeding grounds from human activity, such as overfishing and coastal developments, within the estuary. This is a critical conservation issue for this dolphin population that is facing intense anthropogenic pressure.     

Manganese superoxide dismutase gene coding region polymorphisms lack clinical incidence in general population

Two functional polymorphisms within the manganese superoxide dismutase (MnSOD) gene have been reported to lead to increased oxidative stress damage. The MnSOD 58T > C single nucleotide polymorphism (SNP) within exon 3 changes isoleucine to threonine, leading to decreased thermal stability and reduced enzymatic activity in vivo and in vitro. The MnSOD 60C > T polymorphism within exon 3 changes leucine to phenylalanine, rendering the protein sensitive to redox regulation by intracellular thiols. Thus, the goal of this study was to evaluate the 58T > C and 60C > T MnSOD polymorphisms in a large case-control study. Taqman allelic discrimination assays were developed to identify the 58T > C and 60C > T SNPs in exon 3. Two hundred and eight lung cancer cases and 141 controls were evaluated for these two SNPs, and all 349 subjects were of the wild-type homozygous genotype for both 58C and 60T in exon 3. This study suggests that although the 58T > C and 60C > T polymorphisms reduce MnSOD enzymatic activity, these polymorphisms were not identified in the present case-control study population.     

From Healing to Witchcraft: On Ritual Speech and Roboticization in the Hospital

Healthcare Information Technology (HIT), touted as a panacea by U.S. political actors ranging from Newt Gingrich to Barack Obama, is central to emerging forms of healthcare governance which Holmes et al.—in their critique of the institutionalization of magical thinking brought about by Orwellian techno-Newspeak—have provocatively labeled fascistic. Drawing from data collected over 3 years of working with and teaching continuing education (CE) courses for thousands of registered nurses as lead political educator for the California Nurses Association/National Nurses Organizing Committee (CNA/NNOC), I argue that HIT is an integral component of a broader technological restructuring of healthcare and thus society, both of which are part of a social discourse that is tied to a transformative system of ritual speech, with profound implications for healthcare work, patient health, and democracy.     

Diminished transmission of drug resistant HIV-1 variants with reduced replication capacity in a human transmission model

Background

Different patterns of drug resistance are observed in treated and therapy naïve HIV-1 infected populations. Especially the NRTI-related M184I/V variants, which are among the most frequently encountered mutations in treated patients, are underrepresented in the antiretroviral naïve population. M184I/V mutations are known to have a profound effect on viral replication and tend to revert over time in the new host. However it is debated whether a diminished transmission efficacy of HIV variants with a reduced replication capacity can also contribute to the observed discrepancy in genotypic patterns.As dendritic cells (DCs) play a pivotal role in HIV-1 transmission, we used a model containing primary human Langerhans cells (LCs) and DCs to compare the transmission efficacy M184 variants (HIV-M184V/I/T) to HIV wild type (HIV-WT). As control, we used HIV harboring the NNRTI mutation K103N (HIV-K103N) which has a minor effect on replication and is found at a similar prevalence in treated and untreated individuals.

Results

In comparison to HIV-WT, the HIV-M184 variants were less efficiently transmitted to CCR5⁺ Jurkat T cells by both LCs and DCs. The transmission rate of HIV-K103N was slightly reduced to HIV-WT in LCs and even higher than HIV-WT in DCs. Replication experiments in CCR5⁺ Jurkat T cells revealed no apparent differences in replication capacity between the mutant viruses and HIV-WT. However, viral replication in LCs and DCs was in concordance with the transmission results; replication by the HIV-M184 variants was lower than replication by HIV-WT, and the level of replication of HIV-K103N was intermediate for LCs and higher than HIV-WT for DCs.

Conclusions

Our data demonstrate that drug resistant M184-variants display a reduced replication capacity in LCs and DCs which directly impairs their transmission efficacy. As such, diminished transmission efficacy may contribute to the lower prevalence of drug resistant variants in therapy naive individuals.

     

Sequence of the Corynebacterium glutamicum pyruvate carboxylase gene

Pyruvate carboxylase is an important anaplerotic enzyme replenishing oxaloacetate consumed for biosynthesis during growth, or lysine and glutamic acid production in industrial fermentations. We used regions of homology from pyruvate carboxylase sequences of 12 different species (corresponding to the ATP- and pyruvate-binding sites), to design polymerase chain reaction (PCR) primers for amplifying a fragment of the pyruvate carboxylase (pc) gene from C. glutamicum genomic DNA. This 850-base-pair fragment was used to probe a C. glutamicum cosmid library and four candidate pc cosmids were identified. The fragment was sequenced and the sequence of the complete gene was obtained by several rounds of primer synthesis, PCR on one of the positive cosmids, and sequencing. The C. glutamicumpc sequence shows 64% homology with the pc gene of Mycobacterium tuberculosis and 44% homology with the human pc gene. Regions of ATP, pyruvate and biotin binding have also been identified. Received: 16 December 1997 / Received revision: 31 March 1998 / Accepted: 19 April 1998