Contamination of soil with Toxocara eggs in urban (Prague) and rural areas in the Czech Republic

Contamination of soil with feline and canine ascarid eggs in public parks, backyards and sand pits in Prague, Czech Republic was investigated in this work. Soil samples from shelters and rural areas were also collected. The comparison of soil from different areas (urban, rural, backyards and shelters) exhibited significant difference (chi(2)=32.16, d.f.=3 and p<0.0001). The highest rate of contamination (45%) was found in backyards inhabited by feral cats. The eggs of Toxocara spp. were found in 20.4% of parks, 10% of shelters and 5% of rural samples. Mean egg density per sample from Prague parks was 6.2 eggs/100g of soil. In 126 composite samples from children's and pits, the prevalence of Toxocara eggs was 11.90%. The number of eggs in positive samples varied from 2 to 22 (per 100g). A high proportion (46.9%) of eggs was fully embryonated. There was no difference between the sand pits with or without formal exclusion of dogs (chi(2)=0.6, d.f.=1 and p<0.0001).     

Antiviral effect of a factor from TMV-infected plants on the inoculativity of an insect vector

The capacity of whiteflies (Bemisia tabaci) to acquire and transmit tomato yellow leaf curl virus successfully is reduced if the insect is membrane-fed on a solution of an antiviral factor (AVF) from virus-infected plants. Whiteflies are known to have a native protective mechanism, involving at least two different factors. AVF was shown to act via the same pathway as the above-mentioned protective mechanism, since at least one of the above factors was induced in the insect body by AVF even in virus-free insects     

Escherichia coli O115 forms fewer attaching and effacing lesions in the ovine colon in the presence of E. coli O157:H7

Escherichia coli O115 has been isolated from healthy sheep and was shown to be associated with attaching-effacing (AE) lesions in the large intestine. Following previous observations of interactions between E. coli O157 and O26, the aim of the present study was to assess what influence an O115 AE E. coli (AEEC) would have on E. coli O157 colonisation in vitro and in vivo. We report that E. coli O115- and O157-associated AE lesions were observed on HEp-2 cells and on the mucosa of ligated ovine spiral colon. In single strain inoculum, E. coli O115 associated intimately with HEp-2 cells and the spiral colon in greater numbers than E. coli O157:H7. However, in mixed inoculum studies, the number of E. coli O115 AE lesions was significantly reduced suggesting negative interference by E. coli O157. Use of the ligated colon model in the present work has allowed in vitro observations to be extended and confirmed whilst using a minimum of experimental animals. The findings support a hypothesis that some AEEC can inhibit adhesion of other AEEC in vivo. The mechanisms involved may prove to be of utility in the control of AE pathovars.     

Abundant PrP(CWD) in tonsil from mule deer with preclinical chronic wasting disease.

A monoclonal antibody dot-blot assay was used to evaluate detergent lysates of tonsil tissue from mule deer to detect PrP(CWD), the marker for the cervid transmissible spongiform encephalopathy chronic wasting disease (CWD). Samples of formalin-fixed brain and tonsil tissues from mule deer were examined for PrP(CWD) using immunohistochemistry (IHC) with Mab F99/97.6.1, the gold standard for diagnosis of preclinical CWD. The contralateral tonsil from each of the 143 deer was prepared for confirmatory IHC and as a 10% (wt/vol) detergent lysate without purification or enrichment steps for monoclonal antibody dot-blot assay. PrP(CWD) was detected by dot-blot assay in 49 of 50 samples considered positive by IHC. Forty-eight of the positive samples were evaluated with a quantitative dot-blot assay calibrated with recombinant PrP. Tonsillar PrP(CWD) concentrations ranged from 34 to 1,188 ng per 0.5 mg starting wet weight of tissue. The abundant PrP(CWD) in mule deer tonsil will facilitate development and validation of high-throughput screening tests for CWD in large populations of free-ranging deer.     

Infection criteria,inoculum sources and splash dispersal pattern of <Emphasis Type="Italic">Colletotrichum acutatum</Emphasis> causing bitter rot of apple in New Zealand

Infection of Malus x domestica cv. Royal Gala fruit by Colletotrichum acutatum causing bitter rot was studied in the temperate climate of New Zealand. Temperatures above 15 °C were required for lesions to develop on detached apple wound-inoculated or inoculated without wounding with C. acutatum spores, regardless of maturity. A wetness period of 72 h was required for infection of mature detached apple fruit without wounding. On wound-inoculated detached apple fruits, sporulation was related to temperature and followed a similar pattern. In the field, a mean temperature above 15 °C for 72 h after wound-inoculation was required for lesions to develop. Buds were a more important source of inoculum than twigs, and it was shown that C. acutatum could be isolated more frequently from outer bud scales than from inner scales. Asymptomatic infection of vegetative and reproductive buds was detected. C. acutatum was detected on asymptomic surface-sterilised petals and fruit, more commonly during summer than spring. Symptomless sterilised leaves generally yielded C. acutatum throughout the season, but isolations were more frequent in summer. Recovery of inoculum using a splash meter to detect vertical dispersal showed that in summer inoculum was primarily splashed up from the ground. In spring, inoculum was recovered in similar quantities from all heights up to a metre, suggesting that splash dispersal occurs from the canopy as well as from the ground. A disease cycle for C. acutatum infecting apples and causing bitter rot in New Zealand is suggested.     

Identification and characterization of bacteria isolated from crown galls on stone fruits in Poland

Eighty stone fruit nurseries located in different regions of Poland were examined for the presence of crown gall affected plants. The disease was observed in 39 nurseries, and galls were sampled for bacterial isolation. Out of 1213 isolates, 409 were pre‐identified as Agrobacterium/Rhizobium spp. with 23S rDNA‐based multiplex PCR, and out of these, 315 were pathogenic when tested on sunflowers. Sequence analysis of three housekeeping genes (fusA, recA, rpoD) revealed that 366 strains belonged to Rhizobium rhizogenes, 23 to Agrobacterium tumefaciens species complex, and the rest of the strains were allocated to new phylogenetic lineages. Of these, the most numerous was the lineage allocated in the Pararhizobium genus. Positive results obtained from pathogenicity tests were generally in agreement with results obtained by PCR with primers complementary to T‐DNA except for two strains, which were positive for PCR but negative for the pathogenicity test. All detected Ti plasmids were nopaline‐type. Independent of their pathogenicity, 59% of tested strains were not sensitive to agrocin 84 in in vitro tests. Analysis of biochemical and physiological features distinguished 50 groups with different phenotypic profiles, but the tested traits were not consistent for strains classified to one taxon. This finding shows limited value of biochemical tests in identification procedures. The bacteria causing tumours were heterogeneous and strains classified to different taxa were found even in a single tumour.