An extremely rapid and simple DNA-release method for detection of M. tuberculosis from clinical specimens

A single-step, 5-min lysis method was investigated as a rapid technique to extract genomic DNA from mycobacteria for PCR detection of M. tuberculosis directly from clinical specimens. Of 67 smear-positive clinical specimens, 64 (95.5%) were positive by PCR after this rapid extraction method.     

Induction of the CD23/nitric oxide pathway in endothelial cells downregulates ICAM-1 expression and decreases cytoadherence of Plasmodium falciparum-infected erythrocytes

Cytoadherence of parasitized red blood cells (PRBCs) to postcapillary venules and cytokine production are clearly involved in the pathogenesis of cerebral malaria. Nitric oxide and TNF-alpha have been proposed as major effector molecules both in protective and physiopathological processes during malaria infections. Nitric oxide production has been shown to be induced by engagement of CD23 antigen. This study aimed to investigate the potential role of the CD23/nitric oxide pathway in the control of the cytoadherence of PRBCs on human endothelial cells. We demonstrate that normal human lung endothelial cells (HLECs) are able to express the low affinity receptor for IgE (Fc in RII/CD23), following cell incubation with interleukin 4 or PRBCs. Ligation of the CD23 antigen by a specific anti-CD23 monoclonal antibody at the cell surface of HLECs was found to induce iNOS mRNA and protein expression, NO release and P. falciparum killing. In addition, the specific CD23-engagement on these cells also induced a significant decrease in ICAM-1 expression, an adhesion molecule implicated in PRBCs cytoadherence. These data not only described for the first time the expression of a CD23 antigen at the cell surface of endothelial cells but also suggest a possible new regulatory mechanisms via the CD23/NO pathway during malaria infection.     

Identification of genomic differences between Campylobacter jejuni subsp. jejuni and C. jejuni subsp. doylei at the nap locus leads to the development of a C. jejuni subspeciation multiplex PCR method

Background  

The human bacterial pathogen Campylobacter jejuni contains two subspecies: C. jejuni subsp. jejuni (Cjj) and C. jejuni subsp. doylei (Cjd). Although Cjd strains are isolated infrequently in many parts of the world, they are obtained primarily from human clinical samples and result in an unusual clinical symptomatology in that, in addition to gastroenteritis, they are associated often with bacteremia. In this study, we describe a novel multiplex PCR method, based on the nitrate reductase (nap) locus, that can be used to unambiguously subspeciate C. jejuni isolates.     

LKB1 and Notch Pathways Interact and Control Biliary Morphogenesis

Background

LKB1 is an evolutionary conserved kinase implicated in a wide range of cellular functions including inhibition of cell proliferation, regulation of cell polarity and metabolism. When Lkb1 is inactivated in the liver, glucose homeostasis is perturbed, cellular polarity is affected and cholestasis develops. Cholestasis occurs as a result from deficient bile duct development, yet how LKB1 impacts on biliary morphogenesis is unknown.

Methodology/Principal Findings

We characterized the phenotype of mice in which deletion of the Lkb1 gene has been specifically targeted to the hepatoblasts. Our results confirmed that lack of LKB1 in the liver results in bile duct paucity leading to cholestasis. Immunostaining analysis at a prenatal stage showed that LKB1 is not required for differentiation of hepatoblasts to cholangiocyte precursors but promotes maturation of the primitive ductal structures to mature bile ducts. This phenotype is similar to that obtained upon inactivation of Notch signaling in the liver. We tested the hypothesis of a functional overlap between the LKB1 and Notch pathways by gene expression profiling of livers deficient in Lkb1 or in the Notch mediator RbpJκ and identified a mutual cross-talk between LKB1 and Notch signaling. In vitro experiments confirmed that Notch activity was deficient upon LKB1 loss.

Conclusion

LKB1 and Notch share a common genetic program in the liver, and regulate bile duct morphogenesis.     

Annual cycle of the legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) in southwestern Burkina Faso

Maruca vitrata is an economically significant insect pest of cowpea in sub-Saharan Africa. Understanding the seasonal population patterns of M. vitrata is essential for the establishment of effective pest management strategies. M. vitrata larval populations on cultivated cowpea and adult flying activities were monitored in addition to scouting for host plants and parasitoids during 2 consecutive years in 2010 and 2011 in southwestern Burkina Faso. Our data suggest that M. vitrata populations overlapped on cultivated cowpea and alternate host plants during the rainy season. During the cowpea off-season, M. vitrata maintained a permanent population on the wild host plants Mucuna poggei and Daniella oliveri. The parasitoid fauna include three species, Phanerotoma leucobasis Kri., Braunsia kriegeri End. and Bracon sp. Implications of these finding for pest management strategies are discussed.     

HIV risk among MSM in Senegal: a qualitative rapid assessment of the impact of enforcing laws that criminalize same sex practices

Men who have sex with men (MSM) are at high risk for HIV in Senegal, with a prevalence of 21.5%. In December 2008, nine male HIV prevention workers were imprisoned for "acts against nature" prohibited by Senegalese law. This qualitative study assessed the impact of these arrests on HIV prevention efforts. A purposive sample of MSM in six regions of Senegal was recruited by network referral. 26 in-depth interviews (IDIs) and 6 focus group discussions (FGDs) were conducted in July-August 2009. 14 key informants were also interviewed. All participants reported pervasive fear and hiding among MSM as a result of the December 2008 arrests and publicity. Service providers suspended HIV prevention work with MSM out of fear for their own safety. Those who continued to provide services noticed a sharp decline in MSM participation. An effective response to the HIV epidemic in Senegal should include active work to decrease enforcement of this law.     

Plasmodium falciparum Malaria in Children Aged 0-2 Years: The Role of Foetal Haemoglobin and Maternal Antibodies to Two Asexual Malaria Vaccine Candidates (MSP3 and GLURP)

Background

Children below six months are reported to be less susceptible to clinical malaria. Maternally derived antibodies and foetal haemoglobin are important putative protective factors. We examined antibodies to Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate-rich protein (GLURP), in children in their first two years of life in Burkina Faso and their risk of malaria.

Methods

A cohort of 140 infants aged between four and six weeks was recruited in a stable transmission area of south-western Burkina Faso and monitored for 24 months by active and passive surveillance. Malaria infections were detected by examining blood smears using light microscopy. Enzyme-linked immunosorbent assay was used to quantify total Immunoglobulin G to Plasmodium falciparum antigens MSP3 and two regions of GLURP (R0 and R2) on blood samples collected at baseline, three, six, nine, 12, 18 and 24 months. Foetal haemoglobin and variant haemoglobin fractions were measured at the baseline visit using high pressure liquid chromatography.

Results

A total of 79.6% of children experienced one or more episodes of febrile malaria during monitoring. Antibody titres to MSP3 were prospectively associated with an increased risk of malaria while antibody responses to GLURP (R0 and R2) did not alter the risk. Antibody titres to MSP3 were higher among children in areas of high malaria risk. Foetal haemoglobin was associated with delayed first episode of febrile malaria and haemoglobin CC type was associated with reduced incidence of febrile malaria.

Conclusions

We did not find any evidence of association between titres of antibodies to MSP3, GLURP-R0 or GLURP-R2 as measured by enzyme-linked immunosorbent assay and early protection against malaria, although anti-MSP3 antibody titres may reflect increased exposure to malaria and therefore greater risk. Foetal haemoglobin was associated with protection against febrile malaria despite the study limitations and its role is therefore worthy further investigation.     

Maternal and Perinatal Outcomes by Mode of Delivery in Senegal and Mali: A Cross-Sectional Epidemiological Survey

Objective

In the context of rapid changes regarding practices related to delivery in Africa, we assessed maternal and perinatal adverse outcomes associated with the mode of delivery in 41 referral hospitals of Mali and Senegal.

Study Design

Cross-sectional survey nested in a randomised cluster trial (1/10/2007–1/10/2008). The associations between intended mode of delivery and (i) in-hospital maternal mortality, (ii) maternal morbidity (transfusion or hysterectomy), (iii) stillbirth or neonatal death before Day 1 and (iv) neonatal death between 24 hours after birth and hospital discharge were examined. We excluded women with immediate life threatening maternal or fetal complication to avoid indication bias. The analyses were performed using hierarchical logistic mixed models with random intercept and were adjusted for women''s, newborn''s and hospitals'' characteristics.

Results

Among the 78,166 included women, 2.2% had a pre-labor cesarean section (CS) and 97.8% had a trial of labor. Among women with a trial of labor, 87.5% delivered vaginally and 12.5% had intrapartum CS. Pre-labor CS was associated with a marked reduction in the risk of stillbirth or neonatal death before Day 1 as compared with trial of labor (OR = 0.2 [0.16–0.36]), though we did not show that maternal mortality (OR = 0.3 [0.07–1.32]) and neonatal mortality after Day 1 (OR = 1.3 (0.66–2.72]) differed significantly between groups. Among women with trial of labor, intrapartum CS and operative vaginal delivery were associated with higher risks of maternal mortality and morbidity, and neonatal mortality after Day 1, as compared with spontaneous vaginal delivery.

Conclusions

In referral hospitals of Mali and Senegal, pre-labor CS is a safe procedure although intrapartum CS and operative vaginal delivery are associated with increased risks in mothers and infants. Further research is needed to determine what aspects of obstetric care contribute to a delay in the provision of intrapartum interventions so that practices may be made safer when they are needed.     

Local scale patterns of gene flow and genetic diversity in a crop–wild–weedy complex of sorghum (Sorghum bicolor (L.) Moench) under traditional agricultural field conditions in Kenya

Little information is available on the extent and patterns of gene flow and genetic diversity between cultivated sorghum and its wild related taxa under local agricultural conditions in Africa. As well as expanding knowledge on the evolutionary and domestication processes for sorghum, such information also has importance in biosafety, conservation and breeding programmes. Here, we examined the magnitude and dynamics of crop–wild gene flow and genetic variability in a crop–wild–weedy complex of sorghum under traditional farming in Meru South district, Kenya. We genotyped 110 cultivated sorghum, and 373 wild sorghum individuals using a panel of ten polymorphic microsatellite loci. We combined traditional measures of genetic diversity and differentiation with admixture analysis, population assignment, and analyses of spatial genetic structure to assess the extent and patterns of gene flow and diversity between cultivated and wild sorghum. Our results indicate that gene flow is asymmetric with higher rates from crop to wild forms than vice versa. Surprisingly, our data suggests that the two congeners have retained substantial genetic distinctness in the face of gene flow. Nevertheless, we found no significant differences in genetic diversity measures between them. Our study also did not find evidence of isolation by distance in cultivated or wild sorghum, which suggests that gene dispersal in the two conspecifics is not limited by geographic distance. Overall our study highlights likely escape and dispersal of transgenes within the sorghum crop–wild–weedy complex if genetically engineered varieties were to be introduced in Africa’s traditional farming systems.