Barley Powdery Mildew Populations on Volunteers and Changes in Pathotype Frequencies During Summer on Artificially Inoculated Field Plots

Pathotype frequencies in barley powdery mildew populations were assessed in artificially inoculated barley plots. The field experiment was organised in eighteen 3 m × 3 m plots with different inoculum compositions, obtained by sequential inoculation with three isolates, gl-1, gl-2 and gl-3, shortly after seedling emergence. In the conidia populations before summer, pathotypes corresponding to the inoculated isolates were detected at frequencies in the range 11–42% for GL1, 0–14% for GL2 and 2–34% for GL3. On the volunteers appearing after harvest these three pathotypes were observed at lower frequencies: 0–37% for GL1, 0–12% for GL2 and 0–23% for GL3. The overall ranking of GL1, GL2 and GL3 frequencies was thus the same before and after summer. The populations on volunteers were influenced by both sexual and asexual populations present in the same field at the end of the previous growing season. However, at the small-scale level no simple correlation was found between the frequencies in the conidia populations on volunteers and those in the airborne population, or the conidia populations on the crop before summer, or the calculated expected frequencies in populations of ascospores. During the summer survival, chance events may also have a large influence on pathotype frequencies leading to a high variation between repeated events of transition from the crop to the volunteers.     

Isolation and characterization of atypical Riemerella columbina strains from pigeons and their differentiation from Riemerella anatipestifer

Riemerella columbina (RC) and Riemerella anatipestifer (RA) belong to the genus Riemerella within the family Flavobacteriaceae. While RA is a well-described pathogen of waterfowl and other avian species, only little is known about RC. Previous work reporting the isolation of RC from internal organs of clinically diseased pigeons suggested a potential pathogenic role in this avian species. In this study we examined pharyngeal swabs collected from pigeons and found RC to be widely distributed also among healthy birds. Further characterization of 81 RC-isolates revealed several atypical strains, which differed from all previously described RC-isolates by the lack of aesculin-hydrolysis activity (17 isolates) or by expression of yellow or orange pigmentation (6 isolates). Sequence analysis of the 16S rRNA and outer membrane protein A (ompA) gene supported the affiliation of these strains to the species RC. Aesculin-hydrolysis negative isolates were found to be biochemically indistinguishable from RA. We demonstrated that bacterial fingerprinting using matrix assisted laser desorption/ionisation–time of flight mass spectrometry (MALDI–TOF MS) analysis is useful for the identification and differentiation of RC and RA.     

The effect of ketamine on the MACBAR of sevoflurane in dogs

ObjectiveTo determine the effect of intravenous ketamine on the minimum alveolar concentration of sevoflurane needed to block autonomic response (MAC_BAR) to a noxious stimulus in dogs.Study designRandomized, crossover, prospective design.AnimalsEight, healthy, adult male, mixed-breed dogs, weighing 11.2–16.1 kg.MethodsDogs were anesthetized with sevoflurane on two occasions, 1 week apart, and baseline MAC_BAR (B-MAC_BAR) was determined on each occasion. MAC_BAR was defined as the mean of the end-tidal sevoflurane concentrations that prevented and allowed an increase (≥15%) in heart rate or invasive mean arterial pressure in response to a noxious electrical stimulus (50 V, 50 Hz, 10 ms). Dogs then randomly received either a low-dose (LDS) or high-dose series (HDS) of ketamine, and treatment MAC_BAR (T-MAC_BAR) was determined. The LDS had an initial loading dose (LD) of 0.5 mg kg^?1 and constant rate infusion (CRI) at 6.25 μg kg^?1 minute^?1, followed, after T-MAC_BAR determination, by a second LD (1 mg kg^?1) and CRI (12.5 μg kg^?1 minute^?1). The HDS had an initial LD (2 mg kg^?1) and CRI (25 μg kg^?1 minute^?1) followed by a second LD (3 mg kg^?1) and CRI (50 μg kg^?1 minute^?1). Data were analyzed with a mixed-model anova and are presented as LSM ± SEM.ResultsThe B-MAC_BAR was not significantly different between treatments. Ketamine at 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, and the maximal decrease (22%) occurred at 12.5 μg kg^?1 minute^?1. The percentage change in MAC_BAR was not correlated with either the log plasma ketamine or norketamine concentration.Conclusions and clinical relevanceKetamine at clinically relevant doses of 12.5, 25, and 50 μg kg^?1 minute^?1 decreased sevoflurane MAC_BAR, although the reduction was neither dose-dependent nor linear.     

Effect of three anthocyaninless genes on germination in tomato (Lycopersicon esculentum Mill.) II. Seed germination under stress conditions

Seeds from four pairs of tomato isogenic/near-isogenic lines (IL/NIL) differing for anthocyaninless of Hoffmann (ah), three pairs of IL/NILs differing for anthocyaninwithout (aw) and six pairs of IL/NILs differing for baby lea syndrome (bls) were evaluated for their germination ability under stress conditions: low and high temperature, salt and osmotic stress. Mutant genes affecting anthocyanin biosynthesis enhanced tomato germination capacity under all above mentioned treatments, except for the aw gene under a PEG-6000 treatment. Testa removal accelerated germination under stress conditions, but differences in time to 50% germination between the wild type lines and their ah-, aw- and bls-IL/NILs although diminished, were not eliminated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of three anthocyaninless genes on germination in tomato (Lycopersicon esculentum Mill.) I. Seed germination under optimal conditions

The effect of three mutant genes affecting anthocyanin biosynthesis – anthocyaninless of Hoffmann (ah), anthocyaninwithout (aw) and baby lea syndrome (bls) – on tomato germination capacities at 24 ° C was investigated. The study was performed on nine anthocyanin containing lines – Apedice, Apeca, Ailsa Craig, Monfavet 167, Monfavet 168, Por, Piernita, VF 36 and VFNT cherry and 13 isogenic/near isogenic lines (IL/NIL) from them: 4 differing for gene ah, 3 differing for gene aw and 6 differing for gene bls). In the majority of the anthocyaninless IL/NILs germination began earlier than that in the wild type lines. Significant differences were observed in the time to 50% germination between the anthocyanin-containing and the anthocyaninless IL/NILs except for the most rapidly germinating line VFNT cherry. Seed weight, water uptake, effect of testa removal and presence or absence of maternal effects in F1 germination responses were investigated in order to elucidate the causes of the more rapid germination in the anthocyaninless IL/NILs. The increased amount of water uptake by the anthocyaninless lines, the shorter treatment time necessary for their testa removal, the important maternal effects in the genetic variability of the time to 50% germination and the differences in germination capacities between the wild type and the mutant IL/NILs after testa removal, indicated that the seed coat and the endosperm had to be affected by the effects of the three genes in a way that caused enhanced germination. This revised version was published online in July 2006 with corrections to the Cover Date.     

'The bigger the better'--mothers' social networks and child nutrition in Andhra Pradesh

OBJECTIVE: It is hypothesised that mothers' social networks can positively affect child nutrition through the sharing of health knowledge and other resources. The present study describes the composition of mothers' networks, examines their association with child nutrition, and assesses whether health knowledge is shared within networks. DESIGN AND SETTING: Cross-sectional data for mothers of young children from Andhra Pradesh (south India) were combined with existing data from the Young Lives study, in which the mothers were participating (n = 282). RESULTS: The composition of social networks varied between urban and rural areas, with urban networks being larger, more female, more literate and with a greater proportion of members living outside the household and being non-family. There was a positive association between child's height-for-age Z-score and mother's network size and network literacy rate. The association with network literacy was stronger among the poorest households. Women commonly reported seeking or receiving health advice from network members.CONCLUSION: Big and literate social networks are associated with better child nutrition, especially among the poor. The dissemination of health knowledge between network members is a plausible way in which social networks benefit child nutrition in India. Further research into the underlying mechanisms is necessary to inform the development of interventions that channel health information through word of mouth to the most excluded and vulnerable families.