Mapping of schistosomiasis and soil-transmitted helminthiasis in the regions of centre, East and West Cameroon

Background

Schistosomiasis and soil-transmitted helminthiasis (STH) are widely distributed in Cameroon. Although mass drug administration (MDA) of mebendazole is implemented nationwide, treatment with praziquantel was so far limited to the three northern regions and few health districts in the southern part of Cameroon, based on previous mapping conducted 25 years ago. To update the disease distribution map and determine where treatment with praziquantel should be extended, mapping surveys were conducted in three of the seven southern regions of Cameroon, i.e. Centre, East and West.

Methodology

Parasitological surveys were conducted in April–May 2010 in selected schools in all 63 health districts of the three targeted regions, using appropriate research methodologies, i.e. Kato-Katz and urine filtration.

Principal Findings

The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. Schistosoma mansoni was the most prevalent schistosome species, with an overall prevalence of 5.53%, followed by S. haematobium (1.72%) and S. guineensis (0.14%). The overall prevalence of schistosomiasis across the three regions was 7.31% (95% CI: 6.86–7.77%). The prevalence for Ascaris lumbricoides was 11.48 (95% CI: 10.93–12.04%), Trichuris trichiura 18.22% (95% CI: 17.56–18.90%) and hookworms 1.55% (95% CI: 1.35–1.78%), with an overall STH prevalence of 24.10% (95% CI: 23.36–24.85%) across the three regions. STH was more prevalent in the East region (46.57%; 95% CI: 44.41–48.75%) in comparison to the Centre (25.12; 95% CI: 24.10–26.17%) and West (10.49%; 95% CI: 9.57–11.51%) regions.

Conclusions/Significance

In comparison to previous data, the results showed an increase of schistosomiasis transmission in several health districts, whereas there was a significant decline of STH infections. Based on the prevalence data, the continuation of annual or bi-annual MDA for STH is recommended, as well as an extension of praziquantel in identified moderate and high risk communities for schistosomiasis.     

Diversity of Listeria species in urban and natural environments

A total of 442 Listeria isolates, including 234 Listeria seeligeri, 80 L. monocytogenes, 74 L. welshimeri, 50 L. innocua, and 4 L. marthii isolates, were obtained from 1,805 soil, water, and other environmental samples collected over 2 years from four urban areas and four areas representing natural environments. Listeria spp. showed similar prevalences in samples from natural (23.4%) and urban (22.3%) environments. While L. seeligeri and L. welshimeri were significantly associated with natural environments (P ≤ 0.0001), L. innocua and L. monocytogenes were significantly associated with urban environments (P ≤ 0.0001). Sequencing of sigB for all isolates revealed 67 allelic types with a higher level of allelic diversity among isolates from urban environments. Some Listeria spp. and sigB allelic types showed significant associations with specific urban and natural areas. Nearest-neighbor analyses also showed that certain Listeria spp. and sigB allelic types were spatially clustered within both natural and urban environments, and there was evidence that these species and allelic types persisted over time in specific areas. Our data show that members of the genus Listeria not only are common in urban and natural environments but also show species- and subtype-specific associations with different environments and areas. This indicates that Listeria species and subtypes within these species may show distinct ecological preferences, which suggests (i) that molecular source-tracking approaches can be developed for Listeria and (ii) that detection of some Listeria species may not be a good indicator for L. monocytogenes.     

Over-expression of <Emphasis Type="Italic">CONSTANS-LIKE 5</Emphasis> can induce flowering in short-day grown <Emphasis Type="Italic">Arabidopsis</Emphasis>

To ensure that the initiation of flowering occurs at the correct time of year, plants need to integrate a diverse range of external and internal signals. In Arabidopsis, the photoperiodic flowering pathway is controlled by a set of regulators that include CONSTANS (CO). In addition, Arabidopsis plants also have a family of genes with homologies to CO known as CO-LIKE (COL) about which relatively little is known. In this paper, we describe the regulation and interactions of a novel member of the family, COL5. The expression of COL5 is under circadian and diurnal regulation, but COL5 itself does not appear to affect circadian rhythms. COL5, like CO, is regulated by GIGANTEA. Furthermore, COL5 is expressed in the vascular tissue. Using COL5 over-expressing lines we show that, under short days, constitutive expression of COL5 affects flowering time and the expression of the floral integrator genes, FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CO 1. Constitutive expression of COL5 partially suppresses the late flowering phenotype of the co-mutant plants. However, plants with loss of COL5 function do not show altered flowering. Taken together, our results suggest that COL5 has COL activity, but may either not have a role in regulating flowering in wild-type plants or may act redundantly with other flowering regulators. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Deciphering the Transcriptional Regulation of Cholesterol Catabolic Pathway in Mycobacteria: IDENTIFICATION OF THE INDUCER OF KstR REPRESSOR*

Cholesterol degradation plays a prominent role in Mycobacterium tuberculosis infection; therefore, to develop new tools to combat this disease, we need to decipher the components comprising and regulating the corresponding pathway. A TetR-like repressor (KstR) regulates the upper part of this complex catabolic pathway, but the induction mechanism remains unknown. Using a biophysical approach, we have discovered that the inducer molecule of KstR in M. smegmatis mc²155 is not cholesterol but 3-oxo-4-cholestenoic acid, one of the first metabolic intermediates. Binding this compound induces dramatic conformational changes in KstR that promote the KstR-DNA interaction to be released from the operator, retaining its dimeric state. Our findings suggest a regulatory model common to all cholesterol degrading bacteria in which the first steps of the pathway are critical to its mineralization and explain the high redundancy of the enzymes involved in these initial steps.     

Cloning and characterization of the UDP-sugar hydrolase gene (ushA) of Enterobacter aerogenes IFO 12010

A bacterial alkaline phosphatase (BAP, the phoA gene product) is primarily responsible for the hydrolysis of the substrates 5-bromo-4-chloro-3-indolylphosphate-p-toluidine (XP) and p-nitrophenyl phosphate (pNPP). Using these substrates and an E. coli phoA mutant, we have cloned Enterobacter aerogenes genes conferring an XP(+) phenotype. Two types of clones were identified based on phenotypic tests and DNA sequences. One of them is a E. aerogenes phoA gene (XP(+), pNPP(+)) as expected; surprisingly the other one was found to be a ushA gene (XP(+), pNPP(-)), which encodes an UDP (uridine 5'-diphosphate)-sugar hydrolase. The E. aerogenes ushA gene shares high sequence identity with ushA of E. coli and the mutationally silent ushA0 gene of Salmonella typhimurium at both the nucleotide (over 79%) and amino acid (over 93%) levels. Expression of the E. aerogenes ushA gene in E. coli produced high level of UDP-sugar hydrolase, as confirmed by TLC (thin layer chromatography) analysis together with a presence of a strong band due to a XP hydrolysis on a polyacrylamide gel.     

Rosaceae conserved orthologous set (RosCOS) markers as a tool to assess genome synteny between Malus and Fragaria

Intertribal comparisons of genome synteny between phylogenetically distant genera in Rosaceae, such as Malus (apple) and Fragaria (strawberry), have previously been hampered by a lack of transferable markers that can be used as anchor points between genetic maps. The availability of conserved orthologous set (COS) markers recently developed for this family, coupled with the release of the Malus?×?domestica and Fragaria vesca draft genome sequences, provide new tools for comprehensive pairwise comparisons. The genetic mapping of 56 Rosaceae COS (RosCOS) markers revealed 21 regions of genomic synteny between apple and strawberry. Information concerning the location of RosCOS markers on 15 of 17 apple linkage groups (LG) and all seven LG of strawberry was used to assess the ancestral relationships between the two genera. Four differences in orientation of ancestral chromosome fragments on extant LG were identified in comparison with previous studies, as well as two potential insertions, two potential translocations, and two potential inversions. The set of orthologous markers developed for use in genetic mapping in Rosaceae, in combination with high-throughput analysis, will allow the exploration of chromosome evolution and refinement of ancestral relationships within the family, orientation, and anchoring of genome sequences as they become available and provide resources to develop markers for nonsequenced genomes within the family.     

A Caenorhabditis elegans Wild Type Defies the Temperature–Size Rule Owing to a Single Nucleotide Polymorphism in tra-3

Ectotherms rely for their body heat on surrounding temperatures. A key question in biology is why most ectotherms mature at a larger size at lower temperatures, a phenomenon known as the temperature–size rule. Since temperature affects virtually all processes in a living organism, current theories to explain this phenomenon are diverse and complex and assert often from opposing assumptions. Although widely studied, the molecular genetic control of the temperature–size rule is unknown. We found that the Caenorhabditis elegans wild-type N2 complied with the temperature–size rule, whereas wild-type CB4856 defied it. Using a candidate gene approach based on an N2 × CB4856 recombinant inbred panel in combination with mutant analysis, complementation, and transgenic studies, we show that a single nucleotide polymorphism in tra-3 leads to mutation F96L in the encoded calpain-like protease. This mutation attenuates the ability of CB4856 to grow larger at low temperature. Homology modelling predicts that F96L reduces TRA-3 activity by destabilizing the DII-A domain. The data show that size adaptation of ectotherms to temperature changes may be less complex than previously thought because a subtle wild-type polymorphism modulates the temperature responsiveness of body size. These findings provide a novel step toward the molecular understanding of the temperature–size rule, which has puzzled biologists for decades.     

The cell adhesion receptor carcinoembryonic antigen-related cell adhesion molecule 1 regulates nucleocytoplasmic trafficking of DNA polymerase delta-interacting protein 38

The homophilic cell-cell adhesion receptor CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1, CD66a) acts as a regulator of contact-dependent cell survival, differentiation, and growth. It is involved in the control of proliferation in hematopoietic and epithelial cells and can act as a tumor suppressor. In this study, we identify DNA polymerase delta-interacting protein 38 (PDIP38) as a novel binding partner for CEACAM1-L and CEACAM1-S. We show that PDIP38 can occur in the nucleus, in the cytoplasm and at the plasma membrane in NBT-II, IEC18, RBE, and HeLa cells and that the distribution in NBT-II cells is influenced by the confluency of the cells. We also demonstrate that the interaction of CEACAM1 and PDIP38 is of functional importance in NBT-II cells, which co-express the long and the short CEACAM1 isoform. In subconfluent, proliferating NBT-II cells, perturbation of CEACAM1 by antibody clustering induces increased binding to PDIP38 and results in rapid recruitment of PDIP38 to the plasma membrane. The same treatment of confluent, quiescent NBT-II cells leads to a different response, i.e. translocation of PDIP38 to the nucleus. Together, our data show that PDIP38 can shuttle between the cytoplasmic and the nuclear compartments and that its subcellular localization is regulated by CEACAM1, implicating that PDIP38 may constitute a novel downstream target of CEACAM1 signaling.