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Potential Hosts (potential + hosts)
Selected AbstractsMolecular mechanisms of pathogenicity: how do pathogenic microorganisms develop cross-kingdom host jumps?FEMS MICROBIOLOGY REVIEWS, Issue 3 2007Peter Van Baarlen Abstract It is common knowledge that pathogenic viruses can change hosts, with avian influenza, the HIV, and the causal agent of variant Creutzfeldt,Jacob encephalitis as well-known examples. Less well known, however, is that host jumps also occur with more complex pathogenic microorganisms such as bacteria and fungi. In extreme cases, these host jumps even cross kingdom of life barriers. A number of requirements need to be met to enable a microorganism to cross such kingdom barriers. Potential cross-kingdom pathogenic microorganisms must be able to come into close and frequent contact with potential hosts, and must be able to overcome or evade host defences. Reproduction on, in, or near the new host will ensure the transmission or release of successful genotypes. An unexpectedly high number of cross-kingdom host shifts of bacterial and fungal pathogens are described in the literature. Interestingly, the molecular mechanisms underlying these shifts show commonalities. The evolution of pathogenicity towards novel hosts may be based on traits that were originally developed to ensure survival in the microorganism's original habitat, including former hosts. [source] THE INFLUENCE OF SAE LOCUS KNOCKOUT ON EXOPROTEINS IN STAPHYLOCOCCUS AUREUSJOURNAL OF FOOD SAFETY, Issue 3 2010JUNNI TANG ABSTRACT The sae operon is a key regulator in Staphylococcus aureus, which is known as an important infective and toxigenic bacterial pathogen. For the exploration of virulence factors expressed in the secreted exoprotein fraction are being controlled by sae operon, the relationship between the sae locus and exoproteins was investigated in this study. The homologous recombination vector pBT2,sae was constructed and the sae deletion mutant strain was successfully obtained. The results showed that the sae locus played an important role in the production of thermonucleases and other exoproteins. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed different exoprotein profiles between parent strain and mutant strain, in which three bands were visibly weakened. The results revealed that sae locus was involved in the regulation on exoproteins, some of which play a known fundamental role in the virulence of S. aureus. PRACTICAL APPLICATIONS This study presents that knocking out the sae gene locus in a specific Staphylococcus aureus strain results in reduced thermonuclease action, and also in reduced levels of proteins in the vicinity of 42 and 32 kDa molecular weight in sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) gels, indicating that their production is dependent on the sae locus. Practically, these proteins are associated with virulence traits, and with the pathogen's response to the environment and in potential hosts, which could be helpful for understanding the pathogenicity of S. aureus and also for further studies on the role of selected genes in the pathogenicity of S. aureus. [source] Reaction of Certain Solanaceous and Asteraceous Plant Species to Inoculation with Phytophthora infestans in CameroonJOURNAL OF PHYTOPATHOLOGY, Issue 6 2004D. A. Fontem Abstract Experiments were conducted to detect potential hosts of Phytophthora infestans, causal agent of potato late blight among weeds occurring in Cameroon. Isolates of P. infestans isolated from garden huckleberry (Solanum scabrum), potato (S. tuberosum) and tomato (S. lycopersicon) were inoculated on detached leaves of 12 solanaceous and 14 asteraceous species collected from the potato agroecosystem in the western highlands of Cameroon. Isolates of P. infestans from huckleberry and potato infected the same host plants as well as gboma eggplant (S. macrocarpon) and two asteraceous weeds; Billy goatweed (Ageratum conyzoides) and Dichrocephala (Dichrocephala integrifolia). Inoculum from potato caused late blight symptoms on haemorrhage plant (Aspilia africana); while inoculum from tomato resulted in late blight on worowo (Solanecio biafrae). This is the first report of late blight infection on S. macrocarpon, A. conyzoides, Sol. biafrae and Asp. africana in Cameroon. The research results indicate that some asteraceous and solanaceous weeds may be alternative hosts of P. infestans in the potato agroecosystem. [source] Egg performance on an egg-carrying bug.OIKOS, Issue 2 2001Experiments in the field Selection of oviposition sites has direct influence on female fitness. Differences in offspring survival among sites should favour females to select oviposition sites with the highest survival. Golden egg bug females (Phyllomorpha laciniata; Coreidae, Heteroptera) use conspecifics as oviposition substrates. Most eggs are laid on the back of the bug but they can be found on all body parts. Females never carry their own eggs, and males commonly carry eggs received without copulation with the donor. We examined differences in egg survival relative to paternity to the egg, host sex and body size and attachment of an egg on a host's body in the field. We also studied which bugs received eggs. Egg loss was surprisingly common: 30,80% of recaptured individuals lost eggs during a six-day period. Unexpectedly, host's paternity to the eggs did not affect egg survival. Also, egg loss did not differ among hosts in respect to other parameters studied. Males received more eggs than females, but survival of the eggs was not better on a male's back than on a female's back. Since egg loss is common in the golden egg bug, we suggest that female oviposition strategy to lay eggs on conspecifics is not perfect. This is due to active behaviour of potential hosts (for example, rejected oviposition attempts) or lack of suitable oviposition substrates (conspecifics) in the field. Since eggs do not survive unless carried, females may be acting opportunistically, doing the best job possible by laying eggs on available conspecifics. [source] Orientation of specialist and generalist fungivorous ciid beetles to host and non-host odoursPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2000Roger Guevara Abstract Most ciids (Ciidae) are strict fungivores specialized on fruit bodies of wood-rotting fungi. The Ciidae includes both specialist and generalist species. Recent evidence suggests that ciids locate and discriminate their potential hosts based mainly on fungal odours. In this study, we investigated the field distribution of ciids in a local woodland near Bath, U.K. We also evaluated experimentally the behavioural responses of ciids to host and non-host fungi in an olfactometer, and explored potential differences in putative aroma compounds in host fungi. Our field data showed that Octotemnus glabriculus, Cis boleti and Cis nitidus have preference for one host species, whereas C. bilamellatus has no preference. The experimental evidence was in accordance with the field observations. The specialists O. glabriculus, C. boleti and C. nitidus were specifically attracted to odour compounds of their preferred host fungi: Coriolus versicolor for the first two beetles and Ganoderma adspersum for the latter one. By contrast, the generalist C. bilamellatus was attracted to odours from C. versicolor, G. adspersum and Piptoporus betulinus. The evidence from this and other published studies suggest that ciids depend mainly on fruit body odours for location and discrimination of their host fungi. In accordance with this, we observed diffierential behavioural responses of ciids to aroma compounds of host and non-host species. [source] | ||||||||||