Advantages of larval control for African malaria vectors: Low mobility and behavioural responsiveness of immature mosquito stages allow high effective coverage

Background  

Based on sensitivity analysis of the MacDonald-Ross model, it has long been argued that the best way to reduce malaria transmission is to target adult female mosquitoes with insecticides that can reduce the longevity and human-feeding frequency of vectors. However, these analyses have ignored a fundamental biological difference between mosquito adults and the immature stages that precede them: adults are highly mobile flying insects that can readily detect and avoid many intervention measures whereas mosquito eggs, larvae and pupae are confined within relatively small aquatic habitats and cannot readily escape control measures.     

A mitochondrial DNA variant 10398G>A in breast cancer among South Indians: An original study with meta-analysis

The m.10398G > A polymorphism in the MT-ND3 gene has been linked to the manifestation of several neurodegenerative disorders and cancers. Several research groups have analyzed the association between m.10398G > A polymorphism and breast cancer; however, the results do not follow a consensus. We have studied this polymorphism in three Dravidian populations from South India. Analysis on 716 cases and 724 controls found no association between m.10398G > A polymorphism and breast cancer [OR = 0.916 (0.743–1.128); P = 0.409]. Menopausal stratification also revealed no significant association in either pre-menopausal or post-menopausal breast cancer groups. In addition, we undertook a meta-analysis on 16 study groups, comprising a total of 7202 cases and 7490 controls. The pooled odds ratio suggested no significant association of m.10398G > A substitution with breast cancer [OR = 1.016 (0.85–1.22); P = 0.86]. In conclusion, there is no evidence of association between m.10398G > A polymorphism and breast cancer risk among South Indian women. Meta-analysis suggested no overall correlation between this polymorphism and breast cancer risk.     

MalariaSphere: A greenhouse-enclosed simulation of a natural Anopheles gambiae (Diptera: Culicidae) ecosystem in western Kenya

Background  

The development and implementation of innovative vector control strategies for malaria control in Africa requires in-depth ecological studies in contained semi-field environments. This particularly applies to the development and release of genetically-engineered vectors that are refractory to Plasmodium infection. Here we describe a modified greenhouse, designed to simulate a natural Anopheles gambiae Giles ecosystem, and the first successful trials to complete the life-cycle of this mosquito vector therein.     

Comparative performance of the Mbita trap, CDC light trap and the human landing catch in the sampling of Anopheles arabiensis, An. funestus and culicine species in a rice irrigation in western Kenya

Background

IL-1β and IL-1RA levels are higher in the serum of cerebral malaria patients than in patients with mild malaria. Recently, the level of IL1B expression was reported to be influenced by a polymorphism in the promoter of IL1, IL1B -31C>T.

Methods

To examine whether polymorphisms in IL1B and IL1RA influence the susceptibility to cerebral malaria, IL1B -31C>T, IL1B 3953C>T, and IL1RA variable number of tandem repeat (VNTR) were analysed in 312 Thai patients with malaria (109 cerebral malaria and 203 mild malaria patients).

Results

In this population, IL1B -31C>T and IL1RA VNTRwere detected, while IL1B 3953C>T (i.e., IL1B 3953T) was not observed in the polymorphism screening for 32 patients. Further analyses for IL1B -31C>T and IL1RA VNTR in 110 cerebral malaria and 206 mild malaria patients showed no significant association of these polymorphisms with cerebral malaria.

Conclusion

The present results suggest that IL1B -31C>T and IL1RA VNTR polymorphisms do not play a crucial role in susceptibility or resistance to cerebral malaria.     

The laminin β1-competing peptide YIGSR induces a hypercontractile,hypoproliferative airway smooth muscle phenotype in an animal model of allergic asthma

Background

Fibroproliferative airway remodelling, including increased airway smooth muscle (ASM) mass and contractility, contributes to airway hyperresponsiveness in asthma. In vitro studies have shown that maturation of ASM cells to a (hyper)contractile phenotype is dependent on laminin, which can be inhibited by the laminin-competing peptide Tyr-Ile-Gly-Ser-Arg (YIGSR). The role of laminins in ASM remodelling in chronic asthma in vivo, however, has not yet been established.

Methods

Using an established guinea pig model of allergic asthma, we investigated the effects of topical treatment of the airways with YIGSR on features of airway remodelling induced by repeated allergen challenge, including ASM hyperplasia and hypercontractility, inflammation and fibrosis. Human ASM cells were used to investigate the direct effects of YIGSR on ASM proliferation in vitro.

Results

Topical administration of YIGSR attenuated allergen-induced ASM hyperplasia and pulmonary expression of the proliferative marker proliferating cell nuclear antigen (PCNA). Treatment with YIGSR also increased both the expression of sm-MHC and ASM contractility in saline- and allergen-challenged animals; this suggests that treatment with the laminin-competing peptide YIGSR mimics rather than inhibits laminin function in vivo. In addition, treatment with YIGSR increased allergen-induced fibrosis and submucosal eosinophilia. Immobilized YIGSR concentration-dependently reduced PDGF-induced proliferation of cultured ASM to a similar extent as laminin-coated culture plates. Notably, the effects of both immobilized YIGSR and laminin were antagonized by soluble YIGSR.

Conclusion

These results indicate that the laminin-competing peptide YIGSR promotes a contractile, hypoproliferative ASM phenotype in vivo, an effect that appears to be linked to the microenvironment in which the cells are exposed to the peptide.     

Eleven ancestral gene families lost in mammals and vertebrates while otherwise universally conserved in animals

Background  

Gene losses played a role which may have been as important as gene and genome duplications and rearrangements, in modelling today species' genomes from a common ancestral set of genes. The set and diversity of protein-coding genes in a species has direct output at the functional level. While gene losses have been reported in all the major lineages of the metazoan tree of life, none have proposed a focus on specific losses in the vertebrates and mammals lineages. In contrast, genes lost in protostomes (i.e. arthropods and nematodes) but still present in vertebrates have been reported and extensively detailed. This probable over-anthropocentric way of comparing genomes does not consider as an important phenomena, gene losses in species that are usually described as "higher". However reporting universally conserved genes throughout evolution that have recently been lost in vertebrates and mammals could reveal interesting features about the evolution of our genome, particularly if these losses can be related to losses of capability.     

Quantifying the relationship between disease severity and the amount of Aphanomyces euteiches detected in roots of alfalfa and pea with a real-time PCR assay

A real-time PCR assay was used to quantify the relationship in alfalfa and pea between disease severity and the amount of Aphanomyces euteiches detected in roots. The study included isolates of race 1 and race 2 of the alfalfa pathovar of A. euteiches and an isolate obtained from diseased pea. Spearman rank correlations between pathogen DNA content and disease severity index (DSI) ratings were positive ( ? 0.57) and significant (P  0.0007) for individual alfalfa plants, bulked alfalfa plant samples, and individual pea plants. In all experiments, significantly more pathogen was detected in susceptible populations than in resistant populations. The results clearly demonstrate that resistance to A. euteiches in both alfalfa and pea is characterized by a reduction in pathogen colonization relative to levels observed for susceptible reactions. The assay was very specific for A. euteiches, producing very linear assays with DNA extracted from pathogen isolates obtained from alfalfa, pea, and bean. Possible applications of the assay in conjunction with other real-time PCR assays specific to other legume pathogens are discussed in relation to simultaneous disease screening for multiple plant pathogens and the study of microbial population dynamics in mixed plant infections.     

Caerulein secretion by dermal glands in xenopus laevis

Since gastrin and its related peptides are secreted by a minority population of widely dispersed cells in mamamalian tissues it has, in the past, been difficult to study the subcellular aspects of their secretion. From published reports (1, 2) it seemed possible that a satisfactory system for such studies might be provided by the skin of certain amphibians such as Xenopus laevis since in these tissues high concentrations of peptides such as caerulein exist, and there is some indication (3) that this, or a similar gastrin-like peptide, may be a dermal gland secretory product. We have therefore explored this possibility by studying the structure, secretory process, and secretory product of the most prominent non mucous type of gland in the skin of X. laevis. These studies clearly demonstrate that most, if not all, of the caerulein in which the skin is contained in secretion granules within the dermal glands and that its release can be specifically evoked by adrenergic stimulation. The release process by a holocrine mechanism expels all of the stored secretion onto the skin surface and thus for biosynthetic studies it should now be possible to synchronize the processes which lead to the replenishment of the peptide.