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Post Inoculation (post + inoculation)

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Life Sciences75%

Selected Abstracts

Phenotypic and genetic analysis of the Triticum monococcum,Mycosphaerella graminicola interaction

NEW PHYTOLOGIST, Issue 4 2008
Hai-Chun Jing
Summary ,,Here, the aim was to understand the cellular and genetic basis of the Triticum monococcum,Mycosphaerella graminicola interaction. ,,Testing for 5 yr under UK field conditions revealed that all 24 T. monococcum accessions exposed to a high level of natural inocula were fully resistant to M. graminicola. When the accessions were individually inoculated in the glasshouse using an attached leaf seeding assay and nine previously characterized M. graminicola isolates, fungal sporulation was observed in only three of the 216 interactions examined. Microscopic analyses revealed that M. graminicola infection was arrested at four different stages post-stomatal entry. When the inoculated leaves were detached 30 d post inoculation and incubated at 100% humidity, abundant asexual sporulation occurred within 5 d in a further 61 interactions. ,,An F2 mapping population generated from a cross between T. monococcum accession MDR002 (susceptible) and MDR043 (resistant) was inoculated with the M. graminicola isolate IPO323. Both resistance and in planta fungal growth were found to be controlled by a single genetic locus designated as TmStb1 which was linked to the microsatellite locus Xbarc174 on chromosome 7Am. ,,Exploitation of T. monococcum may provide new sources of resistance to septoria tritici blotch disease. [source]

Comparative Analysis of Phytophthora infestans Induced Gene Expression in Potato Cultivars with Different Levels of Resistance

PLANT BIOLOGY, Issue 6 2005
B. Ros
Abstract: Differential gene expression was analyzed after infection with Phytophthora infestans in six potato cultivars with different levels of resistance to late blight. To verify the infection of the potato leaflets, the amount of phytopathogen mRNA within the plant material was quantified by real-time quantitative PCR. The expression of 182 genes selected from two subtracted cDNA libraries was studied with cDNA array hybridization using RNA from non-infected and infected potato leaflets. Gene up- and down-regulation were clearly detectable in all cultivars 72 h post inoculation. Gene expression patterns in susceptible cultivars differed from those in potato varieties with a higher level of resistance. In general, a stronger gene induction was observed in the susceptible cultivars compared to the moderately to highly resistant potato varieties. Five genes with the highest homology to stress and/or defence-related genes were induced specifically in the susceptible cultivars. Four genes responded to pathogen attack independently of the level of resistance of the cultivar used, and three genes were repressed in infected tissue of most cultivars. Even in the absence of P. infestans infection, six genes showed higher expression levels in the somewhat resistant cultivars Bettina and Matilda. Possible reasons for the different levels of gene expression are discussed. [source]

Inhibition of bacterial translocation by chronic ethanol consumption in the rat,

APMIS, Issue 12 2001
VALERIA BENDER BRAULIO
Chronic ethanol ingestion has been associated with small intestine morphological changes, disrupted host mucosal defenses and bacterial overgrowth. Since bacterial translocation (BT) may result from such alterations, we have investigated the potential effect of chronic ethanol consumption on BT. For this purpose, male Wistar rats were fed a liquid diet containing 5% v/v ethanol for 4 weeks (EG, n=16), and a pair-fed group received equal daily amounts of calories in a similar diet without ethanol (PFG, n=16). On experimental day 29, distal ileum ligature and small intestine inoculation of a tetracycline-resistant E. coli strain (Tc®E. coli R6) followed by duodenal ligature was performed. After 1 or 5 h post inoculation, mesenteric lymph nodes, liver, spleen and kidney were excised. Unexpectedly, rats of the EG presented markedly less BT to the mesenteric lymph nodes (p<0.001) and to the other organs examined compared to rats of the PFG. This BT inhibition was observed at 1 and 5 h after bacterial inoculation, and may be attributed exclusively to chronic ethanol ingestion. Since alcoholism is well known to decrease host immunity, these results suggest that other factors, independent of the immune function, may be involved in the BT inhibition observed in this study. [source]

Enhancement of immunity and resistance in mice by pig IL-6 gene and CpG motifs encapsulated in chitosan nanoparticle

BIOTECHNOLOGY JOURNAL, Issue 2 2008
Qian Chen
Abstract This study was conducted to explore the synergetic effect of a novel plasmid containing a porcine IL-6 gene and CpG motifs on immunity of mice in order to develop an effective adjuvant to boost resistance against infection. The synthetic oligodeoxynucleotide containing 11 CpG motifs was inserted into the reconstructed VR1020 plasmid containing the pig IL-6 gene (VRPIL6), designated VRIL6C, and then encapsulated in chitosan nanoparticles (CNP) prepared by ionic cross linkage, designated VRIL6C-CNP. The 3-week old mice were injected, respectively, with VRIL6C-CNP, VRIL6-CNP, CpG-CNP and VR1020-CNP to detect the changes of immunity. At 28 days post inoculation, the mice were challenged with virulent hemolytic serotype 2 Streptococcus to test their resistance against infection. The results showed that there was a significant increase in immunoglobulins and interleukins in mice receiving VRIL6C-CNP compared with the control groups, as well as an increase in the lymphocytes and monocytes in the inoculated mice, so that the immunity was remarkably improved in the VRIL6C-CNP group. The challenge provoked stronger immunity and protection against infection in the VRIL6C-CNP group than in the control mice that manifested severe symptoms and lesions. This suggests that VRIL6C-CNP could remarkably enhance the nonspecific immunity of mice, and facilitate the development of an effective immunopotentiator to promote the resistance of the animals against infection. [source]