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Twelve commercial 5-component clostridial vaccines with known variations in potency of the blackleg (Clostridium chauvoei) component, were simultaneously tested in sheep and guinea pigs. Controlled challenge experiments provided evidence of a highly significant correlation in the response of the 2 species. The guinea pig laboratory model is considered to be a valid indicator of field performance for vaccines containing blackleg antigen. 相似文献
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SUMMARY Most stock losses caused by annual ryegrass toxicity occur because stockowners unknowingly allow their stock to graze annual ryegrass (Lollum rigidum) Infected with the bacterium Clavlbacter toxicus. To help stockowners avoid losses we have developed criteria for a testing service to determine the risk of poisoning before the pasture is grazed. Low, medium and high risk categories were selected using samples of dry, mature ryegrass seedheads collected by stockowners from untreated, Infected pastures In South Australia. The proportion of toxic paddocks in each risk category over all the seasons tested was 11%;, 32%; and 76%;, respectively, and these accounted for 7%;, 14%; and 79%; of total stock losses. The proportion of paddocks in which stock were poisoned did not vary significantly between years, was not affected by variation in sample weight, and did not vary between South Australia and Western Australia. 相似文献
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Two-year-old Picea sitchensis (Queen Charlotte Islands and Oregonprovenances), Pseudotsuga menziesii, Larix kaempferi, Larixeurolepis, Pinus sylvestris and Pinus nigra var. maritima werelifted at intervals during two winters and planted within 24h on a nearby second rotation site. Physiological conditionat planting, measured by root growth potential and fine rootelectrolyte leakage, and outplanting performance were significantlyinfluenced by lifting date. There were consistent differencesin the species' response to lifting date. Planting out in Septemberresulted in poor survival. Survival of P. sitchensis liftedin October until April was >90 per cent. Pinus sylvestrisand P. nigra had survivals of >90 per cent when lifted inNovember and January respectively until March. There was noclear pattern in P. menziesii performance. Both L. kaempferiand L. eurolepis had two periods of good survival—Octoberand March—with significantly poorer survival and growthassociated with mid-winter planting. The double peak in larchperformance was closely related to root growth potential; lowmid-winter establishment was associated with root growth potentialsof <5 even though the nursery root systems were in excellentcondition as assessed by electrolyte leakage. 相似文献
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β-甘露聚糖酶的产酶菌种、条件及部分性质研究 总被引：12，自引：0，他引：12
杨幼慧 《华南农业大学学报》2001,22(2):86-88
利用刚果红以筛选法从芽孢杆菌中筛选到1株产β－甘露聚糖酶的理想菌株，即枯草杆菌（Bacillus subtills)NCIMB 11034。该菌产酶条件以槐豆胶或魔芋胶作为碳源，以酵母抽提物作为氮源，25℃培养27h为宜，该酶最适作用温度60℃，最适作用pH5.4,60℃保温3h酶活性不损失，有较好的应用前景。 相似文献
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