Orthologous gene-expression profiling in multi-species models: search for candidate genes

Microarray-driven gene-expression profiles are generally produced and analyzed for a single specific experimental model. We have assessed an analytical approach that simultaneously evaluates multi-species experimental models within a particular biological condition using orthologous genes as linkers for the various Affymetrix microarray platforms on multi-species models of ventilator-associated lung injury. The results suggest that this approach may be a useful tool in the evaluation of biological processes of interest and selection of process-related candidate genes.     

Physiological Heterothallism and Sexuality in Euascomycetes: A Partial History

Copyright 1998 Academic Press.     

Mortality of eggs of stored-product insects held under vacuum: effects of pressure, temperature, and exposure time

Low pressure applied to a commodity creates a low-oxygen atmosphere that can be effective to control stored-product insects. Previous work determined that eggs of several species of stored-product insects were among the most tolerant life stages to low pressure. The current study was conducted to determine the mortality of eggs in response to various pressures, temperatures, and exposure times. An initial experiment determined that the sensitivity of eggs to vacuum varied with their age. Eggs of Plodia interpunctella (Hübner) were most sensitive to low pressure when they were 3 or 48 h old, whereas those of Rhyzopertha dominica (F.) were most sensitive at 12 and 120 h of age. In subsequent experiments, eggs of Cadra cautella (Walker), P. interpunctella, R. dominica, and Tribolium castaneum (Herbst) were exposed to pressures of 50, 75, 100, 200, and 300 mmHg in glass chambers at 5, 15, 22.5, 30, and 37.5 degrees C for times ranging from 12 to 168 h. Time-mortality data were subjected to probit analyses and lethal dose ratios were computed to determine differences in lethal time values among species across the 25 low pressure-temperature combinations for each species. In all four species the mortality of eggs increased with increasing exposure time and temperature. Low temperatures and high pressures were the least effective conditions for killing eggs, compared with high temperatures combined with low pressures in all species investigated. These results provide important guidelines for developing treatment schedules for disinfestation of commodities on a commercial scale.     

Increased incidence of pertussis and parapertussis in HIV-1-positive adolescents vaccinated previously with whole-cell pertussis vaccine

We investigated 296 adolescents (11–18 years), who had been immunized previously with the three doses of DPT vaccines. 48 were diagnosed positive for HIV-1. Nasopharyngeal swabs were obtained from 296 adolescents who presented with persistent cough and nasopharyngeal secretions. Nasopharyngeal swabs (calcium alginate) specimens were collected by passing the swabs through the nares into the posterior nasopharynx and rotating the swabs for a few seconds. The swabs were plated for culture of Bordetella organisms in charcoal cephalexin blood agar (CCBA). The CCBA plates were incubated for 2–6 days at 35 °C in a humid aerobic atmosphere. The suspected, shiny (mercury-like) colonies were tested by slide agglutination with antisera to B. pertussis and B. parapertussis, and urease, oxidase activities were performed. Results indicate that out of 48 HIV-1-positive adolescents, 18 had positive cultures for Bordetella organisms (14, Bordetella pertussis, and 4, Bordetella parapertussis). Of 248 HIV-1-negative subjects, 3 had Bordetella organisms (2, Bordetella pertussis, 1, Bordetella bronchiseptica). One of the subjects, a boy, aged 14 years, with Bordetella bronchiseptica had a dog as pet, which was found to be infected. The results indicate that adolescents with HIV-1 infection, despite being vaccinated against pertussis have a higher rate of infection when exposed to pertussis bacteria than HIV-1-negative adolescents. This revised version was published online in August 2006 with corrections to the Cover Date.     

Characterization of biocontrol traits in the entomopathogenic nematode Heterorhabditis georgiana (Kesha strain), and phylogenetic analysis of the nematode’s symbiotic bacteria

Our objective was to estimate the biocontrol potential of the recently discovered entomopathogenic nematode species Heterorhabditis georgiana (Kesha strain). Additionally, we conducted a phylogenetic characterization of the nematode’s symbiotic bacterium. In laboratory experiments, we compared H. georgiana to other entomopathogenic nematodes for virulence, environmental tolerance (to heat, desiccation, and cold), and host seeking ability. Virulence assays targeted Acheta domesticus, Agrotis ipsilon, Diaprepes abbreviatus, Musca domestica, Plodia interpunctella, Solenopsis invicta, and Tenebrio molitor. Each assay included H. georgiana and five or six of the following species: Heterorhabditis floridensis, Heterorhabditis indica, Heterorhabditis mexicana, Steinernema carpocapsae, Steinernema feltiae, Steinernema rarum, and Steinernema riobrave. Environmental tolerance assays included Heterorhabditis bacteriophora, H. georgiana, H. indica, S. carpocapsae, S. feltiae, and S. riobrave (except cold tolerance did not include S. carpocapsae or S. riobrave). Host seeking ability was assessed in H. bacteriophora, H. georgiana, S. carpocapsae, and Steinernema glaseri, all of which showed positive orientation to the host with S. glaseri having greater movement toward the host than S. carpocapsae (and the heterorhabditids being intermediate). Temperature range data (tested at 10, 13, 17, 25, 30 and 35 °C) indicated that H. georgiana can infect Galleria mellonella between 13 and 35 °C (with higher infection at 17–30 °C), and could reproduce between 17 and 30 °C (with higher nematode yields at 25 °C). Compared with other nematode species, H. georgiana expressed low or intermediate capabilities in all virulence and environmental tolerance assays indicating a relatively low biocontrol potential. Some novel observations resulted from comparisons among other species tested. In virulence assays, H. indica caused the highest mortality in P. interpunctella followed by S. riobrave; S. carpocapsae caused the highest mortality in A. domesticus followed by H. indica; and S. riobrave was the most virulent nematode to S. invicta. In cold tolerance, S. feltiae exhibited superior ability to cause mortality in G. mellonella (100%) at 10 °C, yet H. bacteriophora and H. georgiana exhibited the ability to produce attenuated infections at 10 °C, i.e., the infections resumed and produced mortality at 25 °C. In contrast, H. indica did not show an ability to cause attenuated infections. Based on the phylogenetic analysis, the bacterium associated with H. georgiana was identified as Photorhabdus luminescens akhurstii.     

Functional response of <Emphasis Type="Italic">Pteromalus cerealellae</Emphasis> (Hymenoptera: Pteromalidae) on the cowpea weevil, <Emphasis Type="Italic">Callosbruchus maculatus</Emphasis> (Coleoptera: Bruchidae), and interaction between parasitism and cowpea varietal susceptibility

Laboratory studies were carried out to determine the functional response of the parasitoid, Pteromalus cerealellae (Boucek) to cowpea weevil, Callosobruchus maculatus (F.) hosts, and the relationship between parasitism and cowpea variety susceptibility to the weevil. The attack response of P. cerealella to weevil larvae was best described by a type III functional response using an egg limitation model. The mean attack rate (a) of the parasitoid was estimated as 1.7 and the upper limit of the response was 24 weevil larvae per individual parasitoid within a 48-h period. The results also showed that cowpea varieties resistant to weevil infestation supported fewer weevil progeny and facilitated a greater suppression of the weevil by the parasitoid. The parasitoid progeny index, a measure that compares the number of the parasitoid progeny to the number of the beetle progeny was higher in cowpea weevil resistant varieties than in susceptible varieties. Additionally, the presence of P. cerealellae resulted in reduced weight losses of cowpea caused by the weevil infestation in both susceptible and resistant varieties.     

Expression of Toll-like receptor 2 is up-regulated in monocytes from patients with chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is characterised by pulmonary and systemic inflammation which flare-up during episodes of acute exacerbation (AECOPD). Given the role of Toll-like receptors (TLRs) in the induction of inflammatory responses we investigated the involvement of TLRs in COPD pathogenesis.

Methods

The expression of TLR-2, TLR-4 and CD14 in monocytes was analyzed by flow cytometry. To study the functional responses of these receptors, monocytes were stimulated with peptidoglycan or lipopolysaccharide and the amounts of TNFα and IL-6 secreted were determined by ELISA.

Results

We found that the expression of TLR-2 was up-regulated in peripheral blood monocytes from COPD patients, either clinically stable or during AECOPD, as compared to never smokers or smokers with normal lung function. Upon stimulation with TLR-2 ligand monocytes from COPD patients secreted increased amounts of cytokines than similarly stimulated monocytes from never smokers and smokers. In contrast, the expressions of TLR-4 and CD14 were not significantly different between groups, and the response to lipopolysaccharide (a TLR-4 ligand) stimulation was not significantly different either. At discharge from hospital TLR-2 expression was down-regulated in peripheral blood monocytes from AECOPD patients. This could be due to the treatment with systemic steroids because, in vitro, steroids down-regulated TLR-2 expression in a dose-dependent manner. Finally, we demonstrated that IL-6, whose plasma levels are elevated in patients, up-regulated in vitro TLR-2 expression in monocytes from never smokers.

Conclusion

Our results reveal abnormalities in TLRs expression in COPD patients and highlight its potential relationship with systemic inflammation in these patients.

     

Tolerance of pupae and pharate adults of Callosobruchus subinnotatus Pic (Coleoptera: Bruchidae) to modified atmospheres: a function of metabolic rate

Three developmental stages (pupae, early pharate and late pharate adults) of Callosobruchus subinnotatus (Pic.) were investigated for their tolerance or susceptibility to four modified atmospheres. Two of these atmospheres were hypercarbic and two were hypoxic. The hypercarbic atmospheres were found to cause mortality earlier than hypoxic atmospheres. Late pharate adults died earlier than pupae or early pharate adults. Late pharate adults that survived the exposure took a longer time to eclose than the pupae or early pharate adult.Using high resolution microrespirometric techniques, it was possible to record the oxygen consumption rate and CO(2) output of different developmental stages in air. The metabolic rate was determined manometrically as the oxygen uptake rate at an ambient temperature of 25 degrees C. The oxygen uptake rate differed significantly between groups of 20 individuals of different stages (p<0.01; t-test). The lowest rate of oxygen uptake (510.6+/-52.2 &mgr;l g(-1) h(-1)) was recorded in pupae. Higher oxygen uptake rates were found in early pharate adults (668.4+/-45.6 &mgr;l g(-1) h(-1)) and late pharate adults (1171.2+/-45.0 &mgr;l g(-1) h(-1)), and adult beetles (1310.4+/-53.4 &mgr;l g(-1) h(-1)). The patterns of CO(2) release were similar to those of oxygen uptake. CO(2) release was highest in eclosed adults and late pharate adults followed by early pharate adults, and lowest in pupae. The mode of CO(2) release ranged from continuous CO(2) release in pupae to discontinuous CO(2) release in late pharate and eclosed adults. Thus, high metabolic rates, and perhaps, in conjunction with discontinuous CO(2) of late pharate adults are responsible for their higher susceptibility to modified atmospheres than pupae and early pharate adults.     

Sex pheromones of Callosobruchus subinnotatus and C. maculatus (Coleoptera: Bruchidae): congeneric responses and role of air movement

Females of Callosobruchus spp. are known to produce sex pheromones that attract males. These sex pheromones cannot be adopted for use in pest management without first investigating the responses of the males in the windless conditions of storage environments. Consequently, behavioural bioassays of Callosobruchus subinnotatus Pic males were conducted in an olfactometer in the absence of air-flow. Under these conditions males were found to be able to follow odour trails to the source. However, the latency period was longer in diffusional bioassays than for insects in a Y-tube olfactometer that provided directional wind cues. The highest percentage of males reached the pheromone source when components of the pheromones, (E)-3-methyl-2-heptenoic acid (E32A) and (Z)-3-methyl-2-heptenoic acid (Z32A), were formulated in a 50:50 or 25:75 ratio. Males of C. maculatus (Fabricius) responded to sex pheromone of C. subinnotatus, but males of C. subinnotatus did not respond to that of C. maculatus. The two sex pheromone components of C. subinnotatus are also constituents of C. maculatus sex pheromone. These two components may be potentially useful in monitoring the populations of both species in stored beans. It is postulated that (Z)-3-methyl-3-heptenoic acid (Z33A), the major component of the sex pheromone of C. maculatus, must have acted as an antagonist inhibiting response of C. subinnotatus to the sex pheromone of C. maculatus.