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Cowpea, which has now become an important protein source for the teeming populace of Nigerians, especially those living in the humid agro-ecological zones of south-western Nigeria, is severely attacked by diseases. The causal agents of these diseases find the environment more conducive for survival and hence induced disease conditions in the host plant, causing significant yield reduction. This paper reviews the present situation of the cowpea diseases in the humid forest agro-ecologies of south-western Nigeria.  相似文献   
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Background

The recent determination of the complete nucleotide sequence of several Mycobacterium tuberculosis (MTB) genomes allows the use of comparative genomics as a tool for dissecting the nature and consequence of genetic variability within this species. The multiple alignment of the genomes of clinical strains (CDC1551, F11, Haarlem and C), along with the genomes of laboratory strains (H37Rv and H37Ra), provides new insights on the mechanisms of adaptation of this bacterium to the human host.

Findings

The genetic variation found in six M. tuberculosis strains does not involve significant genomic rearrangements. Most of the variation results from deletion and transposition events preferentially associated with insertion sequences and genes of the PE/PPE family but not with genes implicated in virulence. Using a Perl-based software islandsanalyser, which creates a representation of the genetic variation in the genome, we identified differences in the patterns of distribution and frequency of the polymorphisms across the genome. The identification of genes displaying strain-specific polymorphisms and the extrapolation of the number of strain-specific polymorphisms to an unlimited number of genomes indicates that the different strains contain a limited number of unique polymorphisms.

Conclusion

The comparison of multiple genomes demonstrates that the M. tuberculosis genome is currently undergoing an active process of gene decay, analogous to the adaptation process of obligate bacterial symbionts. This observation opens new perspectives into the evolution and the understanding of the pathogenesis of this bacterium.  相似文献   
3.
Twenty cassava cultivars were screened in micro-plot experiments in the green house of Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan for root-knot nematode resistance. Four weeks after planting, each plant was inoculated with 5000 eggs of Meloidogyne incognita. There were three replications per cultivar. The plants were uprooted and assessed for resistance after 60 days of inoculation. Assessment of plant damaged was determined by gall index and reproductive factor. Based on host status rating, 3 cultivars were found to be resistant, 4 cultivars were tolerant, 10 cultivars ere susceptible while .3 cultivars were hypersusceptible. All the screened cultivars are resistant to cassava mosaic disease and other major pests of cassava like bacterial disease, anthracnose disease, cassava green mite and cassava mealy bug. They are all high yielding, suitable for food, industry and livestock feed.  相似文献   
4.
A plant that showed morphological closeness to Aspilia africana (Pers) C. D. Adams (Asteraceae) was spotted and collected in 2015 along Afe Babalola University road, Ado‐Ekiti, Ekiti State, Nigeria with coordinates 7°36′59.99″N, 5°12′60.00″E. However, upon closer observation some distinct and peculiar characteristics that clearly distinguished it from Aspilia africana were revealed, e.g. sterility of the disc florets and production of achenes by ray florets only. Another striking character of the plant was total emptying of the capitulum after achene maturation, leaving an empty capitulum cup on the plant. Literature and herbarium searches revealed that the plant had neither been reported from West Tropical Africa nor collected in any herbarium in Nigeria before. The plant was eventually identified as Melampodium divaricatum (L.) which is an annual erect herb, distributed in tropical and subtropical regions but mostly restricted to Mexico, North America and Central America. Morphological, reproductive and cytological studies carried out on the plant revealed it to possess a highly branched erect pigmented stem, simple opposite sub sessile leaves with acute apex and distantly serrated margins, capitula with yellow unisexual disc and ray florets, sterile disc florets, fertile ray florets, relatively high pollen fertility (92.85%), a somatic chromosome number of 2n = 24 and regular formation of 12 bivalents, indicating the plant to be a diploid species. Further studies on Melampodium in Nigeria and a general revision of the flora of West Tropical Africa is suggested as well as the need to monitor M. divaricatum in the region since it appears to have the capacity to become invasive.  相似文献   
5.
International Journal of Peptide Research and Therapeutics - Despite advances in therapy, myocardial infarction (MI) remains a leading cause of death worldwide. Recently, the mitochondrion has been...  相似文献   
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