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Inter Simple Sequence Repeat (ISSR) Analysis of Diploid Coffee Species and Cultivated Coffea arabica L. from Tanzania 总被引：1，自引：0，他引：1
Inter simple sequence repeat (ISSR) markers were used to evaluate levels of genetic similarity among Coffea arabica L. accessions from Tanzania and to estimate levels of genetic similarities in C. arabica and diploid coffee species. The six ISSR primers used generated a total of 82 fragments and the dissimilarity values ranged
from 0.21 to 1. Mean dissimilarity values between provenances (0.56–0.85) were higher than within provenances (0.37–0.68).
Cluster analysis based on Nei’s genetic distances showed C. arabica provenances grouping based on geographical origin. Two major clusters were formed that constituted of provenances from Kilimanjaro
and Arusha in one sub-cluster; Tanga and Morogoro in the other; the second cluster had Mbeya provenances and diploid species,
respectively. The implication is that Mbeya provenances are different from the rest of Tanzanian C. arabica. A principal coordinate analysis (PCA), whose first three coordinates explained 43% of the variation, showed similar groupings
as in the cluster analysis. A separate cluster analysis of diploid species showed a distinct separation of the three species
used. ISSR data gave results similar to previous findings from random amplified polymorphic DNA(RAPD) analysis. The results
also confirm the limited diversity present in cultivated C. arabica in Tanzania 相似文献
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Steed PM Tansey MG Zalevsky J Zhukovsky EA Desjarlais JR Szymkowski DE Abbott C Carmichael D Chan C Cherry L Cheung P Chirino AJ Chung HH Doberstein SK Eivazi A Filikov AV Gao SX Hubert RS Hwang M Hyun L Kashi S Kim A Kim E Kung J Martinez SP Muchhal US Nguyen DH O'Brien C O'Keefe D Singer K Vafa O Vielmetter J Yoder SC Dahiyat BI 《Science (New York, N.Y.)》2003,301(5641):1895-1898
Tumor necrosis factor (TNF) is a key regulator of inflammatory responses and has been implicated in many pathological conditions. We used structure-based design to engineer variant TNF proteins that rapidly form heterotrimers with native TNF to give complexes that neither bind to nor stimulate signaling through TNF receptors. Thus, TNF is inactivated by sequestration. Dominant-negative TNFs represent a possible approach to anti-inflammatory biotherapeutics, and experiments in animal models show that the strategy can attenuate TNF-mediated pathology. Similar rational design could be used to engineer inhibitors of additional TNF superfamily cytokines as well as other multimeric ligands. 相似文献
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Gianmarco?Mugnai Federico?RossiEmail authorView author&#;s OrcID profile Vincent?John?Martin?Noah?Linus?Felde Claudia?Colesie Burkhard?Büdel Stephan?Peth Aaron?Kaplan Roberto?De?Philippis 《Biology and Fertility of Soils》2018,54(1):27-40
Soil inoculation with cyanobacteria (cyanobacterization) is a biotechnological method widely studied to improve soil quality and productivity. During their growth on soil, cyanobacteria excrete exopolysaccharides (EPSs) which glue trichomes to soil particles, in a three-dimensional extracellular polymeric matrix. EPS productivity is an important screening parameter to select proficient inoculants and is affected by growth conditions and abiotic stresses. In this study, we evaluated the capability of the cyanobacterium Schizothrix cf. delicatissima AMPL0116 to form biocrusts when inoculated in sand microcosms under stressing conditions, and the characteristics of the synthesized polymeric matrix. In parallel, we evaluated the characteristics of exopolysaccharidic exudates of the strain when grown in liquid culture, under optimal growth setting. Our results pointed out at significant differences of the exopolymers produced in the two conditions in terms of monosaccharidic composition and molecular weight distribution, and proved the capability of S. cf. delicatissima AMPL0116 to form stable bioaggregates on sandy soils. 相似文献
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Nakazawa K Quirk MC Chitwood RA Watanabe M Yeckel MF Sun LD Kato A Carr CA Johnston D Wilson MA Tonegawa S 《Science (New York, N.Y.)》2002,297(5579):211-218
Pattern completion, the ability to retrieve complete memories on the basis of incomplete sets of cues, is a crucial function of biological memory systems. The extensive recurrent connectivity of the CA3 area of hippocampus has led to suggestions that it might provide this function. We have tested this hypothesis by generating and analyzing a genetically engineered mouse strain in which the N-methyl-D-asparate (NMDA) receptor gene is ablated specifically in the CA3 pyramidal cells of adult mice. The mutant mice normally acquired and retrieved spatial reference memory in the Morris water maze, but they were impaired in retrieving this memory when presented with a fraction of the original cues. Similarly, hippocampal CA1 pyramidal cells in mutant mice displayed normal place-related activity in a full-cue environment but showed a reduction in activity upon partial cue removal. These results provide direct evidence for CA3 NMDA receptor involvement in associative memory recall. 相似文献
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O O Opara L E Carr E Russek-Cohen C R Tate E T Mallinson R G Miller L E Stewart R W Johnston S W Joseph 《Avian diseases》1992,36(3):664-671
Three flocks on 13 different broiler farms were monitored for Salmonella over three consecutive growout periods using the drag swab (DS) technique. One house was consistently negative for Salmonella contamination (7.7%); four houses were consistently positive (30.8%); and eight houses (61.5%) alternated between either a DS Salmonella-negative or -positive status. Simultaneously, numerous environmental parameters of the litter surface were measured, including water activity (Aw), ammonia, temperature, pH, moisture content (MC), ash content, and volatile solids. Analysis of these data as a corollary to either Salmonella-negative or -positive DS results revealed significant correlation coefficients for some of the parameters, especially Aw. The results suggest that there should be further exploration of remedial intervention based on control of some of the physical features of litter (e.g., controlling litter Aw and possibly MC and pH levels) in poultry houses. 相似文献
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Abstract The effect of irrigation and crop load of apple (Malus domestica Borkh cv. Pacific Rose) on the fruit growth and mineral element accumulation was investigated. Fruit growth and changes in the concentration and contents of nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and potassium (K) in the flesh of Pacific Rose? apple fruit were recorded over a growing season at the Massey University Fruit Crops Units orchard in the 1998–99 crop season. Fresh mass showed a linear growth while fruit diameter followed a curvilinear growth pattern during the growing season. Low crop load significantly increased fruit size, particularly during the final expansion phase, whereas irrigation had little effect on this attribute. Both low crop load and frequent irrigation treatments increased fruit growth rate, but the effect of the irrigation treatments fluctuated considerably during the season. The incidence of frait splitting was detected at about 20 WAFB when the fruit attained an asymmetrical growth in shape (L/D). The concentrations of N, P, Ca, Mg, and K declined throughout the sampling period. There was however, an increase in concentrations of P and K at the last harvest. The quantity of individual nutrient elements accumulated by the fruit showed an increasing trend during the season. Nitrogen accumulation however, reached maximum at 16 WAFB after which it declined until the last harvest. Fruit mineral element analysis of sound and split fruit revealed that split fruit had higher concentrations and contents of Mg and K and lower contents of Ca and P. As a result, the ratios of Ca: Mg and Ca: K were lower in split fruit as compared with sound fruit. 相似文献
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A field study for the arid northwest China has been conducted to find water-saving strategies of drip irrigation for dense-planted crops. The annual water consumption for optimal growth was 420 mm, of which soil evaporation was 27% and the foliage transpiration 73%. A relationship between soil water consumption and the irrigation amount, crop yield and water use efficiency were established. It was found that for high crop yield, it is important to maintain rather high soil water content during the two sensitive growth stages: elongation and milky filling stages. It is concluded that with drip irrigation higher yield was achieved although much less water was applied than what was used in block irrigation experiment. 相似文献
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Faraja E. Kiula Eblate E. Mjingo Alex R. Mremi Jaffu O. Chilongola Linus K. Munishi 《The Veterinary quarterly》2021,41(1):242
BackgroundMasai Giraffes have declined dramatically in recent decades due to loss of habitat and illegal hunting. Hence, it is critically important that the epidemiology and etiology of so-called giraffe skin disease (GSD) is understood well.AimTo assess the prevalence and histopathological characteristics of GSD in the Tarangire-Manyara Ecosystem (TME), northern Tanzania.MethodsThe study used road transects to gather field information on GSD. Eighty-four giraffes were sighted by systematic random sampling in the six study sites. Examination of giraffes involved body distribution of lesions, severity of the lesions and whether they were associated with age and sex of the affected giraffes. Five giraffes with GSD were immobilized for tissue collection and histopathological analysis.ResultsPrevalence among adults was 79%. Affected animals typically had 1–5 lesions which were mostly moderate and were predominantly observed on the forelegs. GSD positivity rate was higher among females versus males, whereas males had a higher rate of severe lesions and generally had more lesions than females. Calves showed no lesions. All tissue sections from five affected giraffes showed the presence of large quantities of fungal elements (hyphae and spores) that involved hair shafts and sub-cutaneous tissue after staining with Grocott Methenamine Silver as special fungal staining technique.ConclusionsOur findings suggest the involvement of fungal infection in GSD pathogenesis.Clinical relevanceWe recommend further characterization of the lesions using modern molecular techniques and culture to identify primary and secondary or opportunistic etiologies, and the order in which the pathogens occur in the lesions. 相似文献