Search Results

You are looking at 1 - 10 of 762 items for :

  • "pathogenicity" x
  • Refine by Access: All Content x
Clear All

979 Brennan, J.M., Fagan, B., Van Maanen, A., 2003: Studies on in vitro and pathogenicity of European Fusarium fungi. European Journal of Plant Pathology, 109, 577

Restricted access

Long-term storage of Rhynchosporium secalis cultures is a challenge for any lab managing a working collection of isolates. In this work, the viability and pathogenicity of R. secalis stock cultures were tested after four years of storage at −20 °C in different concentrations of glycerol. Germinability were measured after each storage by collecting spores by coverslips and placing them on water agar in closed Petri dishes at 20–22 °C in the dark and allowed to germinate for 24 h. Additionally, at the end of each storage treatment, conidia were collected by coverslips from sporulated leaf lesions of symptomatic barley leaves and placed under similar conditions as non-stored controls.

Cultures of all stored isolates were viable with a spore germination rate of 72.28% (Rs22) after four years of storage at −20 °C in 60% glycerol. Low viability and contamination were observed when spores were stored in sterile distilled water and in Lima bean agar. All isolates continued to infect barley leaves after 4 years of storage. However, the pathogenicity was significantly (P <0.05) reduced in isolates stored in glycerol as compared with controls.

This work helps to preserve R. secalis for a long term period at −20 °C without any contamination; therefore, due to the low costs our results could be applicable for laboratories that have limited resources.

Restricted access
Acta Microbiologica et Immunologica Hungarica
Authors:
Elisabeth Nagy
,
Edit Urbán
,
J. Sóki
,
J. Sóki
,
Gabriella Terhes
, and
Katalin Nagy

Anaerobic infections are common and can cause diseases associated with severe morbidity, but are easily overlooked in clinical settings. Both the relatively small number of infections due to exogenous anaerobes and the much larger number of infections involving anaerobic species that are originally members of the normal flora, may lead to a life-threatening situation unless appropriate treatment is instituted. Special laboratory procedures are needed for the isolation, identification and susceptibility testing of this diverse group of bacteria. Since many anaerobes grow more slowly than the facultative or aerobic bacteria, and particularly since clinical specimens yielding anaerobic bacteria commonly contain several organisms and often very complex mixtures of aerobic and anaerobic bacteria, considerable time may elapse before the laboratory is able to provide a final report. Species definition based on phenotypic features is often time-consuming and is not always easy to carry out. Molecular genetic methods may help in the everyday clinical microbiological practice in laboratories dealing with the diagnostics of anaerobic infections. Methods have been introduced for species diagnostics, such as 16S rRNA PCR-RFLP profile determination, which can help to distinguish species of Bacteroides, Prevotella, Actinomyces, etc. that are otherwise difficult to differentiate. The use of DNA-DNA hybridization and the sequencing of special regions of the 16S rRNA have revealed fundamental taxonomic changes among anaerobic bacteria. Some anaerobic bacteria are extremely slow growing or not cultivatable at all. To detect them in special infections involving flora changes due to oral malignancy or periodontitis, for instance, a PCR-based hybridization technique is used. Molecular methods have demonstrated the spread of specific resistance genes among the most important anaerobic bacteria, the members of the Bacteroides genus. Their detection and investigation of the IS elements involved in their expression may facilitate following of the spread of antibiotic resistance among anaerobic bacteria involved in infections and in the normal flora members. Molecular methods (a search for toxin genes and ribotyping) may promote a better understanding of the pathogenic features of some anaerobic infections, such as the nosocomial diarrhoea caused by C. difficile and its spread in the hospital environment and the community. The investigation of toxin production at a molecular level helps in the detection of new toxin types. This mini-review surveys some of the results obtained by our group and others using molecular genetic methods in anaerobic diagnostics.

Restricted access

1986 Detection of pathogenic Campylobacter species in blood culture systems J Clin Microbiol 23 709 – 714 . 36. H

Restricted access

1249 McCabe, P.M., Pfeiffer, P., van Alfen, N.K. 1999. The influence of dsRNA viruses on the biology of plant pathogenic fungi. Trends Microbiol. 7: 377

Restricted access

. Apoga , D. , Åkesson , H. , Jansson , H.B. , Odham , G. 2002 . Relationship between production of the phytotoxin prehelminthosporol and virulence in isolates of the plant pathogenic fungus Bipolaris sorokiniana. Eur. J. Plant Pathol

Restricted access

. 14 , 290 – 320 . Lockaby , S. B., Hoerr , F. J., Lauerman , L. H. and Kleven , S. H. ( 1998 ): Pathogenicity of

Restricted access

different stress conditions, six biofilm-forming non-pathogenic Listeria strains were analyzed. The effect of the weak biofilm forming non-pathogenic Listeria strains on the biofilm formation of the strong biofilm-forming Listeria monocytogenes #8 was

Open access

). Pathogenicity, as defined by the non-specific and disease-causing abilities of a causal agent, is the most important fungal trait affecting disease invasion and stability of host resistance ( Xue et al., 2006 ). However, the expression of fungal pathogenicity

Restricted access

., 1995 ; Bottalico and Perrone, 2002 ). Fusarium species causing FHB are pathogens of high concern for the barley production due to their high pathogenicity and ability to cause severe disease under epidemic conditions ( Xue et

Restricted access