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33 3 16 Jin, Y., Singh, R.P. 2006. Resistance in US wheat to recent Eastern African isolates of Puccinia graminis f. sp tritici with virulence

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Proctor, R.H., Hohn, T.M., McCormick, S.P. 1995. Reduced virulence of Gibberella zeae caused by disruption of a trichothecene toxin biosynthetic gene. Mol Plant-Microbe Interact 8(4): 593–601. McCormick S

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Enteropathogenic Escherichia coli (EPEC) bacteria frequently cause severe enteric diseases primarily in children and in young rabbits. Their pathogenicity for pigs has been tested by oral infection of colostrum-deprived newborn, and of severely immunosuppressed weaned pigs, but colonisation of conventional weaned pigs by porcine EPEC has not been experimentally studied. EPEC show similarities to enterohaemorrhagic E. coli (EHEC) additionally carrying shiga toxin genes integrated into the chromosome by lambdoid phages. We have demonstrated earlier that the porcine EPEC prototype strain P86-1390 (O45) could be transduced in vivo (in ligated loops of weaned pigs), by Stx2 phage derived from a human EHEC. Thus, the ability of this porcine EPEC strain to colonise conventional weaned pigs under farming conditions became a question of relevance to human health. To clarify this question, four intragastric infection experiments were performed on a total of 95 conventional weaned pigs. The EPEC P86-1390 and other well-characterised porcine EPEC strains were applied to 54 pigs, leaving 41 weaned pigs as negative controls. In three experiments moderate predispositions were applied: coinfections with enterotoxigenic E. coli (ETEC) or with low-virulence TGE coronavirus, application of fumonisin B1 with a normal therapeutic dose of dexamethasone, and the increase of soybean protein concentration in the feed. A total of 41 weaned pigs served as negative controls inoculated with a commensal porcine E. coli. Housing conditions simulated the farm environment. As an overall result, ileal segments of 18.5% of infected pigs were shown to be colonised by EPEC, while no EPEC were detected in the ilea of controls. Among predisposing factors occurring on farms, feed protein content increased by 20% (26.3% crude protein, provided by 48% soybean meal) seemed to enhance EPEC colonisation and resulted in the mobilisation of spontaneous latent EPEC/ETEC infection. The results indicate that under normal farm conditions porcine EPEC may colonise conventional weaned pigs by inducing ileal attaching effacing (AE) lesions with reasonable frequency, without clinical signs. The results also suggest that conventional weaned pigs may represent undetected reservoirs of porcine EPEC, potentially giving rise to the emergence of new types of EHEC due to natural transduction by Stx phages.

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Orvosi Hetilap
Authors:
Szilvia Fekete
,
Dóra Szabó
,
László Tamás
, and
Gábor Polony

Absztrakt:

Egészségünket a szervezetünkben és a bőrünkön élő sokszínű mikrobaközösség jelentősen meghatározza. A normálflóra tagjai közötti egyensúly elengedhetetlen az egészség fenntartásában. Az újgenerációs szekvenálás gyors, szenzitív módszer, amely a mikrobiom egészének vizsgálatára alkalmas előzetes hipotézis nélkül, és információt ad a rezisztenciáról és a virulenciáról is. Ennek a módszernek a segítségével lehetővé vált betegségekben a patogén baktériumok, illetve az ezek szaporodását gátló, úgynevezett protektív baktériumok azonosítása. A mikrobiom változásainak feltérképezése segít új terápiás célpontok meghatározásában és az antibiotikumok célzott kiválasztásában. Széles spektrumú antibiotikum használatakor a normálflóra hasznos tagjai is kipusztulnak, ami visszatérő vagy krónikussá váló fertőzések kialakulásához vezet. A fül-orr-gégészeti infekciók a leggyakoribb fertőző betegségek az emberi szervezetben és az antibiotikum alkalmazásának vezető okai világszerte. Az egészséges emberben, illetve a fül-orr-gégészeti betegségekben előforduló baktérium-összetétellel kapcsolatban számos molekuláris biológiai vizsgálat történt az utóbbi években. A szerzők ismertetik az egyes fül-orr-gégészeti anatómiai régiók normálflórájának tagjait, és különböző patológiás állapotokban a baktérium-összetétel változásait is összefoglalják. Orv Hetil. 2019; 160(39): 1533–1541.

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Field trials were conducted in the dry and wet seasons of 1998 at Samaru (11°11' N, 07° 38' E, 686 m above sea level) in the northern Guinea savanna of Nigeria, to investigate the potential of cinosulfuron and CGA152005 seed treatments on the reaction of upland rice varieties to Striga hermonthica (Del.) Benth. Seven varieties of upland rice formed the main plots treatments while four levels each of cinosulfuron at 0.1, 0.2, 0.4 and 0.6 g/l and CGA152005 at 0.008, 0.016, 0.032 and 0.064 g/l, as well as two no herbicide treatments of dry sowing and distilled water-soaked planting were assigned to the subplots. The experiment was laid out in a split plot design and replicated three times. The resistant varieties FARO 40 and WAB 56-50 did not support Striga emergence and also produced grain yields which were the maximum, or comparable to the maximum. FARO 11, a susceptible variety, produced high grain yields in spite of support for early, high Striga emergence. In spite of delayed emergence of Striga on FARO 38 and FARO 48, these varieties, as well as FARO 46 and FARO 45, supported high Striga emergence, exhibited high crop reaction scores to Striga and produced low grain yields. The seed treatment of upland rice varieties with cinosulfuron at 0.2 to 0.6 g/l and CGA152005 at 0.032 and 0.064 g/l significantly delayed Striga emergence compared with the lower rates. After seed treatment with cinosulfuron at 0.6 g/l, the susceptible rice variety FARO 38 and the resistant variety WAB 56-50 produced rice grain yields comparable to the maximum obtained with FARO 40 given seed treatment with CGA 152005 at 0.064 g/l. The significant interactions of varieties of upland rice and herbicide seed treatments on the number of days to first Striga emergence, Striga shoot count and crop reaction to Striga confirm the differential influence of various concentrations of the herbicide seed treatments on the virulence of Striga hermonthica on varieties of upland rice.

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Curr Protein Pept Sci 4 6 409 426 . 12. SC Holt 1999 Virulence factors of

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. Relationship between production of the phytotoxin prehelminthosporol and virulence in isolates of the plant pathogenic fungus Bipolaris sorokiniana . Eur. J. Plant Pathol. 108 :519–526. Odham G

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248 Dreiseitl, A. 2004. Virulence frequencies to powdery mildew resistance genes of winter barley cultivars. Plant Protection Sci. 40 :135

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Cereal Research Communications
Authors:
Marie Dufresne
,
Theo Lee
,
Sarrah M’Barek
,
X. Xu
,
X. Zhang
,
Taiguo Liu
,
Wenwei Zhang
,
Gert Kema
,
Marie-Josée Daboussi
, and
Cees Waalwijk

Seong, K., Hou, Z., Tracy, M., Kistler, H.C., Xu, J.R. 2006. Random insertional mutagenesis identifies genes associated with virulence in the wheat scab fungus Fusarium graminearum. Phytopathol. 95: 744

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University Press, Oxford. Evolution of infectious disease Frank, S. A. (1996) Models of parasite virulence. The Quarterly Review of Biology

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