Relationship between African dust carried in the Atlantic trade winds and surges in pediatric asthma attendances in the Caribbean

Asthma is epidemic in developed and developing countries including those in the Caribbean where it is widely believed that African dust, transported in high concentrations in the Trade Winds every year, is a major causative factor. The link between asthma and dust in the Caribbean is based largely on anecdotal evidence that associates sharp increases in the occurrence of asthma symptoms with hazy conditions often caused by dust. Here we report on a 2-year study of the relationship between the daily concentrations of dust measured in on-shore Trade Winds at Barbados and pediatric asthma attendance rates at Queen Elizabeth Hospital (QEH). We looked for large increases in QEH daily attendances in relation to daily dust concentrations as previously suggested by anecdotal observations. We could not find any obvious relationship although there may be more subtle linkages between dust and asthma. Our measurements show, however, that the concentration of dust in the size range under 2.5 μm diameter is sufficiently high as to challenge United States Environmental Protection Agency air quality standards for respirable particles. Thus, African dust may constitute a health threat of a different nature, producing symptoms less obvious than those of asthma.     

Interhemispheric transport of viable fungi and bacteria from Africa to the Caribbean with soil dust

Daily aerosol samples collected in trade winds at Barbados, West Indies, throughout 1996–1997 yielded significant concentrations of viable (culture-forming) bacteria and fungi only when African dust was present. Air masses from the North Atlantic, North America, and Europe yielded no cultivable organisms. The strong association of cultivable organisms with African dust suggests various factors that might be relevant to viability. Although we did not specifically look for pathogens, these same mechanisms could protect them as well. Our results suggest that arid regions could be an important source for the long-range transport of viable microorganisms. The transport of microorganisms to Barbados follows a clear meteorological and seasonal pattern, which suggests that it should be possible to model the transport process and to predict events. Microorganism and dust concentrations were unusually great in 1997, possibly in response to the strong El Niño. This suggests that the long-range transport of microorganisms might be particularly responsive to climate variability in general.     

Conyza sumatrensis (Retz.) E. H. Walker: A new record from Pakistan

Conyza sumatrensis (Retz.) E. H. Walker (Astereae: Asteraceae) has been recorded in Pakistan for the first time. The species is closely associated with C. bonariensis and C. canadensis. It differs from C. bonariensis in its smaller capitula with a small series of marginal and disc florets that lack a purplish-pink apex, but resembles it in disciform capitula. C. sumatrensis differs from C. canadensis in having five-lobed disc florets and lacking well-developed ray florets. The species is widely distributed in the Potohar region, particularly in Rawalpindi and Islamabad.     

Sex differences in heritability of sensitization to<Emphasis Type="Italic"> Blomia tropicalis</Emphasis> in asthma using regression of offspring on midparent (ROMP) methods

A genetic basis for asthma- and atopy-related quantitative traits, such as allergen-specific immunoglobulin E (IgE) levels, has been suggested by the observed familial aggregation of these traits in temperate climates. Less information is available for tropical climates, where different allergens may predominate. Sensitivity to the mite Blomia tropicalis is related to asthma in tropical climates, but heritability of B. tropicalis sensitivity and the impact of age, sex, and other environmental covariates on heritability have not been widely explored. Total and specific IgE levels were measured by immunochemiluminescent assay in 481 members of 29 Barbadian families (comprised of 340 parent-offspring trios or pairs) ascertained through two asthmatic siblings. Trait heritability was estimated using regression of offspring on mid-parent (ROMP) and pairwise correlation analysis of unadjusted IgE levels and on residual values after adjustment for covariates. Heritability of IgE levels to the major antigen of B. tropicalis (Blo t M) estimated by ROMP in 180 complete parent-offspring trios was 0.56. Heritability was consistently greater for male offspring than for female offspring. Similar sex-specific patterns were observed for specific IgE to Dermatophagoides pteronyssinus and total IgE levels and were relatively unaffected by adjustment for covariates. Pairwise correlational analyses of specific and total IgE levels showed similar results. Moderate heritability of Blo t M IgE levels was detected in these Barbadian families and was greater for sons than daughters. Adjustment for covariates had minimal impact. This suggests that future investigations of genetic determinants of IgE levels should include approaches that allow for potential sex differences in their expression.     

The genetic and functional analysis of flavor in commercial tomato: the FLORAL4 gene underlies a QTL for floral aroma volatiles in tomato fruit

Tomato (Solanum lycopersicum L.) has become a popular model for genetic studies of fruit flavor in the last two decades. In this article we present a study of tomato fruit flavor, including an analysis of the genetic, metabolic and sensorial variation of a collection of contemporary commercial glasshouse tomato cultivars, followed by a validation of the associations found by quantitative trait locus (QTL) analysis of representative biparental segregating populations. This led to the identification of the major sensorial and chemical components determining fruit flavor variation and detection of the underlying QTLs. The high representation of QTL haplotypes in the breeders’ germplasm suggests that there is great potential for applying these QTLs in current breeding programs aimed at improving tomato flavor. A QTL on chromosome 4 was found to affect the levels of the phenylalanine‐derived volatiles (PHEVs) 2‐phenylethanol, phenylacetaldehyde and 1‐nitro‐2‐phenylethane. Fruits of near‐isogenic lines contrasting for this locus and in the composition of PHEVs significantly differed in the perception of fruity and rose‐hip‐like aroma. The PHEV locus was fine mapped, which allowed for the identification of FLORAL4 as a candidate gene for PHEV regulation. Using a gene‐editing‐based (CRISPR‐CAS9) reverse‐genetics approach, FLORAL4 was demonstrated to be the key factor in this QTL affecting PHEV accumulation in tomato fruit.     

Crossing-over in the long arm of the X and Y chromosomes in Anopheles culicifacies

Genetic and cytogenetic investigations of two unstable Y-linked translocations in Anopheles culicifacies indicate that crossing over can occur between the X and Y chromosomes in this species. Moreover, these observations suggest that the long arms of the X and Y chromosomes are homologous and that the sex determining mechanism(s) is located in the short arms.     

Qualitative analysis of phospholipids isolated from nonviable plasmodium antigen

Plasmodium berghei infected mouse blood, and Plasmodium knowlesi infected monkey blood were processed by the French Press to prepare Antigen “A,” a parasitic fraction known to impart immunity, and Antigen “B,” a byproduct of Antigen “A” production. Normal mouse erythrocyte material was also prepared.The lipoidal material from these preparations was extracted using chloroform: methanol (1:1) and concentrated under nitrogen. This material was resuspended in chloroform and thin-layer chromatography was used to separate and identify the phospholipids therein. Antigen “A” contained sphingomyelin, phosphatidylcholine, phosphatydylinositol, and phosphatidylethanolamine. Antigen “B,” and uninfected mouse erythrocytic material, contained sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and possibly phosphatidylinositol. The absence of phosphatidylserine in Antigen “A” its presence in Antigen “B,” and in normal mouse material indicates that the protective Antigen “A” is free of host erythrocytic membrane fragments.