Complete Genomic Sequence of the Human Retinoblastoma Susceptibility Gene

A 180,388-bp contig encompassing the human retinoblastoma gene was sequenced in its entirety. Partial analysis of the sequence revealed (1) a high (A + T)/(G + C) ratio and a high density of Line-1 (L1) repeat sequences, suggesting that the locus maps to G-bands 13q14.12 or 13q14.2; (2) Alu repeats that are asymmetrically oriented over a region extending 87 kb; (3) an overabundance of non-Alu-associated poly(A) tracts 10 bp or larger oriented in the antisense rather than the sense direction (36 vs 6); (4) an Alu sequence nested within an L1 repeat, indicating that the expansion of L1 repeats predates at least some of the Alu expansions; (5) at least three newly discovered microsatellite polymorphisms, one of which was subsequently found to be identical to a polymorphism in a microsatellite-based linkage map of the human genome published by another group; and (6) the basis of previously discovered intragenic RFLPs. This sequence should enhance studies of this locus and of the organization of the human genome.     

Genetic linkage of Francois-Neetens fleck (mouchetée) corneal dystrophy to chromosome 2q35

Francois-Neetens fleck (mouchetée) corneal dystrophy is an autosomal dominant corneal dystrophy characterized by scattered small white flecks occurring at all levels of the corneal stroma. We report linkage of the CFD locus to D2S2289 (Z(max)=4.46, theta=0), D2S325 (Z(max)=3.28, theta=0), D2S317 (Z(max)=3.1, theta=0), D2S143 (Z(max)=3.8, theta=0.03), and D2S2382 (Z(max)=5.0, theta=0) on chromosome 2q35. Multipoint analysis confirmed linkage to the region between D2S117 and D2S126 with a maximum multipoint lod score of 5.0 located midway between D2S2289 and D2S325. Analysis of CFD in these same families assuming a 90% penetrance increased the maximum lod score to 6.28 at D2S157.     

The JIL-1 kinase regulates the structure of Drosophila polytene chromosomes

The JIL-1 kinase localizes to interband regions of Drosophila polytene chromosomes and phosphorylates histone H3 Ser10. Analysis of JIL-1 hypomorphic alleles demonstrated that reduced levels of JIL-1 protein lead to global changes in polytene chromatin structure. Here we have performed a detailed ultrastructural and cytological analysis of the defects in JIL-1 mutant chromosomes. We show that all autosomes and the female X chromosome are similarly affected, whereas the defects in the male X chromosome are qualitatively different. In polytene autosomes, loss of JIL-1 leads to misalignment of interband chromatin fibrils and to increased ectopic contacts between nonhomologous regions. Furthermore, there is an abnormal coiling of the chromosomes with an intermixing of euchromatic regions and the compacted chromatin characteristic of banded regions. In contrast, coiling of the male X polytene chromosome was not observed. Instead, the shortening of the male X chromosome appeared to be caused by increased dispersal of the chromatin into a diffuse network without any discernable banded regions. To account for the observed phenotypes we propose a model in which JIL-1 functions to establish or maintain the parallel alignment of interband chromosome fibrils as well as to repress the formation of contacts and intermingling of nonhomologous chromatid regions. Electronic Supplementary Material Supplementary material is available for this article at and accessible for authorised users     

Intraspecific host discrimination and larval competition inMicroplitis croceipes,Microplitis demolitor,Cotesia kazak (HYM.: Braconidae) andHyposoter didymator HYM: Ichneumonidae), parasitoids ofHeliothis virescens (LEP.: Noctuidae)

Intraspecific host discrimination and larval competition were studied forMicroplitis croceipes (Cresson),Microplitis demolitor Wilkinson,Cotesia kazak (Telenga), andHyposoter didymator (Thunberg), solitary endoparasitoids of the tobacco budworm,Heliothis virescens (F.). In ovipositional choice tests between unparasitized and parasitized hosts, the mean number of ovipositions for unparasitized hosts was significantly higher than the mean number of ovipositions for hosts parasitized once by a conspecific female forC. kazak andH. didymator, demonstrating that females of these two species discriminate against hosts recently (within a few seconds) parasitized by a conspecific female. No significant difference in oviposition occurred between these two kinds of hosts forM. croceipes andM. demolitor. Mean percent parasitization by a second conspecific female was determined at 24, 48, and 72 h delays in time between the first and second female attack, and with no delay. Except for the 0 h time delay forC. kazak andH. didymator, percent parasitization by a second conspecific female generally decreased as the delay in time between the first and second female attack increased. When the second parasitization immediately followed the first, one parasitoid larva always eliminated the other by physical combat. With a 24 or 48 h delay between the first and second parasitization, the younger larva was the victor over the older larva forM. croceipes, M. demolitor andC. kazak in at least 50% of the cases. Elimination of older larvae by younger larva was by physical attack. However, forH. didymator, the older instar was the victor, and elimination of younger larvae by older larvae was probably through physiological processes. Further, older larvae ofH. didymator apparently killed the eggs of the second female by physiological processes.      

Interspecific interference between Apoanagyrus lopezi and A. diversicornis, parasitoids of the cassava mealybug Phenacoccus manihoti

The parasitoids Apoanagyrus lopezi De Santis and A. diversicornis (Howard) (Hymenoptera: Encyrtidae) have been introduced into Africa for the biological control of the cassava mealybug Phenacoccus manihoti Matile-Ferrero (Homoptera: Pseudococcidae). We have studied competition between these species to investigate if they can coexist. Here we report on the influence of the simultaneous presence of non-conspecific adult females on searching efficiency on patches. Wasps of either species foraged on discs of cassava leaf with mealybugs, while at the same time different numbers of non-conspecifics were also depleting the patch. Patch area per parasitoid and number of hosts available to each parasitoid were equal in all treatments.In both species, the presence of other foragers clearly affected several aspects of the parasitoids' behaviour. Patch residence time increased with the number of non-conspecifics in A. diversicornis. In both parasitoid species, the proportion of hosts left unparasitized after the patch visit decreased with increasing numbers of females on the patch. The proportions of super- and multiparasitism did not change with the number of females. Both species produced more offspring during a patch visit in the presence of more non-conspecifics. These behavioural changes did not, however, lead to a change in the offspring production rate on patches. A. diversicornis produced offspring at a rate three times that of A. lopezi when one A. lopezi and one A. diversicornis foraged simultaneously. This is the first report of an aspect of interspecific competition where A. diversicornis has an advantage over A. lopezi. Interference between adult females thus promotes coexistence of the two species on P. manihoti.     

A systematic review investigating healthy lifestyle interventions incorporating goal setting strategies for preventing excess gestational weight gain

Background

Excess gestational weight gain (GWG) is an important risk factor for long term obesity in women. However, current interventions aimed at preventing excess GWG appear to have a limited effect. Several studies have highlighted the importance of linking theory with empirical evidence for producing effective interventions for behaviour change. Theorists have demonstrated that goals can be an important source of human motivation and goal setting has shown promise in promoting diet and physical activity behaviour change within non-pregnant individuals. The use of goal setting as a behaviour change strategy has been systematically evaluated within overweight and obese individuals, yet its use within pregnancy has not yet been systematically explored.

Aim of review

To explore the use of goal setting within healthy lifestyle interventions for the prevention of excess GWG.

Data collection and analysis

Searches were conducted in seven databases alongside hand searching of relevant journals and citation tracking. Studies were included if interventions used goal setting alongside modification of diet and/or physical activity with an aim to prevent excess GWG. The PRISMA guidelines were followed and a two-stage methodological approach was used. Stage one focused on systematically evaluating the methodological quality of included interventions. The second stage assessed intervention integrity and the implementation of key goal setting components.

Findings

From a total of 839 citations, 54 full-text articles were assessed for eligibility and 5 studies met the inclusion criteria. Among interventions reporting positive results a combination of individualised diet and physical activity goals, self-monitoring and performance feedback indicators were described as active components.

Conclusion

Interventions based on goal setting appear to be useful for helping women achieve optimal weight gain during pregnancy. However, overweight and obese women may require more theoretically-designed interventions. Further high quality, theoretically-designed interventions are required to determine the most effective and replicable components for optimal GWG.     

The effects of interleukin-8 on airway smooth muscle contraction in cystic fibrosis

Background

Clara cells are the epithelial progenitor cell of the small airways, a location known to be important in many lung disorders. Although migration of alveolar type II and bronchiolar ciliated epithelial cells has been examined, the migratory response of Clara cells has received little attention.

Methods

Using a modification of existing procedures for Clara cell isolation, we examined mouse Clara cells and a mouse Clara-like cell line (C22) for adhesion to and migration toward matrix substrate gradients, to establish the nature and integrin dependence of migration in Clara cells.

Results

We observed that Clara cells adhere preferentially to fibronectin (Fn) and type I collagen (Col I) similar to previous reports. Migration of Clara cells can be directed by a fixed gradient of matrix substrates (haptotaxis). Migration of the C22 cell line was similar to the Clara cells so integrin dependence of migration was evaluated with this cell line. As determined by competition with an RGD containing-peptide, migration of C22 cells toward Fn and laminin (Lm) 511 (formerly laminin 10) was significantly RGD integrin dependent, but migration toward Col I was RGD integrin independent, suggesting that Clara cells utilize different receptors for these different matrices.

Conclusion

Thus, Clara cells resemble alveolar type II and bronchiolar ciliated epithelial cells by showing integrin mediated pro-migratory changes to extracellular matrix components that are present in tissues after injury.     

Atlas of Mexican Triatominae (Reduviidae: Hemiptera) and vector transmission of Chagas disease

Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs) were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.     

Identification of natural killer cell receptor clusters in the platypus genome reveals an expansion of C-type lectin genes

Natural killer (NK) cell receptors belong to two unrelated, but functionally analogous gene families: the immunoglobulin superfamily, situated in the leukocyte receptor complex (LRC) and the C-type lectin superfamily, located in the natural killer complex (NKC). Here, we describe the largest NK receptor gene expansion seen to date. We identified 213 putative C-type lectin NK receptor homologs in the genome of the platypus. Many have arisen as the result of a lineage-specific expansion. Orthologs of OLR1, CD69, KLRE, CLEC12B, and CLEC16p genes were also identified. The NKC is split into at least two regions of the genome: 34 genes map to chromosome 7, two map to a small autosome, and the remainder are unanchored in the current genome assembly. No NK receptor genes from the LRC were identified. The massive C-type lectin expansion and lack of Ig-domain-containing NK receptors represents the most extreme polarization of NK receptors found to date. We have used this new data from platypus to trace the possible evolutionary history of the NK receptor clusters. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.