Metallophytes—a view from the rhizosphere

Abundance of Fabaceae declines in representation through post-fire-succession in fynbos vegetation of the Cape Floristic Region (CFR). This reduction in legume occurrence coincides with a known decline in post-fire soil P availability. It was hypothesized that the disappearance of legume species during post-fire succession is due to an inability to acquire P effectively from sparingly soluble sources. P-acquisition strategies and response to P supply were compared between legume (Aspalathus, Cyclopia, Indigofera, Podalyria) and non-legume (Elegia, Leucadendron, Protea) genera when supplied with 1 or 10 mg P kg^?1 dry sand. Each genus consisted of a seeder (non-persistent) and resprouter (persistent) species. Non-legumes showed a greater investment in below-ground biomass, more root clusters, with higher concentrations of carboxylates exuded by cluster roots and carboxylates that were better suited to the mobilization of sparingly soluble P compared to legumes. The growth response to increased P supply was 53% higher in legumes than in non-legumes. The lack of a growth response to an elevated P supply in the non-legumes was attributed to N-limitation. Legume resprouters had a higher investment in cluster-root biomass and a lower capacity to down-regulate P-uptake than the seeders. Therefore the inability to acquire sufficient P from low concentration and sparingly soluble soil P-sources may contribute to the lack of indigenous legume persistence in fynbos vegetation of the CFR.     

Expression of aromatase,androgen and estrogen receptors in peripheral target tissues in diabetes

Our previous studies have shown that diabetes in the male streptozotocin (STZ)-induced diabetic rat is characterized by a decrease in circulating testosterone and concomitant increase in estradiol levels. Interestingly, this increase in estradiol levels persists even after castration, suggesting extra-testicular origins of estradiol in diabetes. The aim of the present study was to examine whether other target organs of diabetes may be sources of estradiol. The study was performed in male Sprague–Dawley non-diabetic (ND), STZ-induced diabetic (D) and STZ-induced diabetic castrated (Dcas) rats (n = 8–9/group). 14 weeks of diabetes was associated with decreased testicular (ND, 26.3 ± 4.19; D, 18.4 ± 1.54; P < 0.05), but increased renal (ND, 1.83 ± 0.92; D, 7.85 ± 1.38; P < 0.05) and ocular (D, 23.4 ± 3.66; D, 87.1 ± 28.1; P < 0.05) aromatase activity. This increase in renal (Dcas, 6.30 ± 1.25) and ocular (Dcas, 62.7 ± 11.9) aromatase activity persisted after castration. The diabetic kidney also had increased levels of tissue estrogen (ND, 0.31 ± 0.01; D, 0.51 ± 0.11; Dcas, 0.45 ± 0.08) as well as estrogen receptor alpha protein expression (ND, 0.63 ± 0.09; D, 1.62 ± 0.28; Dcas, 1.38 ± 0.20). These data suggest that in male STZ-induced diabetic rats, tissues other than the testis may become sources of estradiol. In particular, the diabetic kidney appears to produce estradiol following castration, a state that is associated with a high degree or renal injury. Overall, our data provides evidence for the extra-testicular source of estradiol that in males, through an intracrine mechanism, may contribute to the development and/or progression of end-organ damage associated with diabetes.     

Sequencing of 6.7 Mb of the melon genome using a BAC pooling strategy

Background  

Cucumis melo (melon) belongs to the Cucurbitaceae family, whose economic importance among horticulture crops is second only to Solanaceae. Melon has a high intra-specific genetic variation, morphologic diversity and a small genome size (454 Mb), which make it suitable for a great variety of molecular and genetic studies. A number of genetic and genomic resources have already been developed, such as several genetic maps, BAC genomic libraries, a BAC-based physical map and EST collections. Sequence information would be invaluable to complete the picture of the melon genomic landscape, furthering our understanding of this species' evolution from its relatives and providing an important genetic tool. However, to this day there is little sequence data available, only a few melon genes and genomic regions are deposited in public databases. The development of massively parallel sequencing methods allows envisaging new strategies to obtain long fragments of genomic sequence at higher speed and lower cost than previous Sanger-based methods.     

Association of serum markers with improvement in clinical response measures after treatment with golimumab in patients with active rheumatoid arthritis despite receiving methotrexate: results from the GO-FORWARD study

Introduction  

The goal of this study was to identify serum markers that are modulated by treatment with golimumab with or without methotrexate (MTX) and are associated with clinical response.     

The Prevalence and Drug Sensitivity of Tuberculosis among Patients Dying in Hospital in KwaZulu-Natal,South Africa: A Postmortem Study

Background

Tuberculosis is the leading cause of death in South Africa by death notification, but accurate diagnosis of tuberculosis is challenging in this setting of high HIV prevalence. We conducted limited autopsies on young adults dying in a single public hospital in the province of KwaZulu-Natal between October 2008 and August 2009 in order to estimate the magnitude of deaths attributable to tuberculosis.

Methods and Findings

We studied a representative sample of 240 adult inpatients (aged 20–45 years) dying after admission to Edendale Hospital. Limited autopsies included collection of respiratory tract secretions and tissue by needle core biopsies of lung, liver, and spleen. Specimens were examined by fluorescent microscopy for acid-fast bacilli and cultured in liquid media; cultures positive for M. tuberculosis were tested for drug susceptibility to first- and second-line antibiotics. Ninety-four percent of our study cohort was HIV seropositive and 50% of decedents had culture-positive tuberculosis at the time of death. Fifty percent of the participants were on treatment for tuberculosis at the time of death and 58% of these treated individuals remained culture positive at the time of death. Of the 50% not receiving tuberculosis treatment, 42% were culture positive. Seventeen percent of all positive cultures were resistant to both isoniazid and rifampin (i.e., multidrug resistant); 16% of patients dying during the initiation phase of their first ever course of tuberculosis treatment were infected with multidrug-resistant bacilli.

Conclusions

Our findings reveal the immense toll of tuberculosis among HIV-positive individuals in KwaZulu-Natal. The majority of decedents who remained culture positive despite receiving tuberculosis treatment were infected with pan-susceptible M. tuberculosis, suggesting that the diagnosis of tuberculosis was made too late to alter the fatal course of the infection. There is also a significant burden of undetected multidrug-resistant tuberculosis among HIV-coinfected individuals dying in this setting. New public health approaches that improve early diagnosis of tuberculosis and accelerate the initiation of treatment are urgently needed in this setting. Please see later in the article for the Editors'' Summary