Blindness associated with toxoplasmosis in canaries.

Seven of 30 canaries in an aviary in New Zealand developed ophthalmic problems. Clinically, 5 birds had unilateral and 2 birds had bilateral lesions characterized by conjunctivitis, crusty exudates on eyelids, and collapse of the eyeball. Microscopic lesions in 12 of 14 eyes examined included inflammation of the choroid and retina, with osseous replacement of the globe in some. Numerous Toxoplasma gondii tachyzoites were seen in the detached retina and vitreous humor of acutely affected birds. The diagnosis of toxoplasmosis was confirmed by immunohistochemical staining with T gondii antiserum. Affected birds had encephalitis, and T gondii was localized in the brains of these by immunohistochemical examination and by use of bioassays in mice. Toxoplasmosis should be considered in differential diagnosis of ophthalmitis in canaries.     

Genotypic Variability in Biomass Protein and Nucleic Acids in Four Linum Species to Sodicity Stress

Differences in gas exchange parameters i.e. carbon exchange rate (CER), transpiration (Tr), water vapor conductance (g) were investigated, under a controlled environment, in a semi-dwarf (SD) Triticum aestivum line, its tall (TL) near isoline and the Payne (PA) variety characterized by small leaves. The plants were maintained in: (a) optimal substrate moisture condition (CTR); (b) salinized by watering with a 0.12 m NaCl solution (SLT); (c) water stressed by withholding waterings during a period of six days (STR); (d) stressed and salinized during the same period and with the same saline solution (S + S). CER and Tr were negatively affected by the stresses; SLT and S + S treatments had a higher WUE compared to their respective controls CTR and STR.
SD line had a better performance in terms of CER and WUE, particularly when water and salt stresses interacted. Leaf anatomy and assimilation/internal CO₂ concentration curves contributed to explaining the SD performance.     

Antibody response to crustacean ectoparasites in rainbow trout, Oncorhynchus mykiss (Walbaum), immunized with Argulus foliaceus L. antigen extract

Abstract. A humoral antibody response was demonstrated by ELISA in rainbow trout immunized intraperitoneally with extracts from the branchiuran ectoparasite Argulus foliaceus. A similar immunization protocol produced a higher titre response in a rabbit. Both trout and rabbit identified several antigenic components on immunoblots. ELISA and immunoblotting indicated that rainbow trout and rabbit anti-A. foliaceus sera identified components from the parasitic copepods Lepeophtheirus salmonis and Caligus elongatus.     

Effects of dietary molybdenum on nematode and host during Haemonchus contortus infection in lambs.

The addition of molybdenum (0.05 mmol kg-1 dry-matter) to the diet of lambs given a trickle infection of Haemonchus contortus larvae (500 third stage larvae d-1 over six weeks) reduced mean faecal egg counts (epg) from 3952 to 2312 +/- 402 by 32 days (P less than 0.02) and greatly reduced the mean number of worms recovered from the abomasum 14 days after infection ceased (907 compared with 4167: P less than 0.01). Infection reduced haemoglobin concentrations less in lambs given molybdenum although the difference was small relative to the reduction in worm burden. Lambs not given molybdenum had low intraepithelial mast cell counts in the abomasal mucosa and less abomasal hypertrophy than expected from abomasal parasitism. Molybdenum did not consistently reduce the copper status of the host or the parasite. Previous exposure to molybdenum greatly reduced protein but not proteinase activity in, or secreted by, adult worms cultured for eight hours. It is suggested that molybdenum either increased the inflammatory response which preceded worm rejection or that it indirectly enhanced that reaction by reducing the effectiveness of copper-dependent, anti-inflammatory enzymes in the gastrointestinal mucosa.     

Temporal ELISA response of rams to Brucella ovis following experimental infection or vaccination

Sera from rams vaccinated with antigens extracted chaotropically from Brucella ovis by potassium thiocyanate treatment were used to optimise a whole-cell, enzyme-linked immunosorbent assay (CELISA) and to monitor the temporal serological response of rams which had been challenged with infected semen by the intranasal or intrapreputial route. Three patterns of CELISA response were detected. Thirteen of 15 rams intranasally challenged did not respond serologically (pattern 1 or nil response). Only one of 15 rams in the intranasal group exhibited a rise and fall response with CELISA (pattern 2), while another showed a rise and surge response (pattern 3). The numbers of rams in the intrapreputial group which displayed a pattern 1 or 2 or 3 response were four, nine and two, respectively. No ram with a pattern 2 response excreted B ovis in the semen or showed any other evidence of infection, whereas rams with a pattern 3 response excreted B ovis in the semen and developed palpable lesions. Intrapreputially challenged rams that were CELISA-positive consistently mounted an antibody response against B ovis about two to four weeks earlier than intranasally challenged rams.     

Relationships between acid-base balance, serum composition and colostrum absorption in newborn calves

Twenty-seven newborn Holstein bull calves were bottle-fed 2 litres of pooled colostrum which had been stored at -20 degrees C. Blood gas analysis before feeding showed a partially compensated respiratory acidosis in most of the calves, although they all appeared to be clinically normal. Mean venous blood pH was 7.346, carbon dioxide tension (PCO2) was 57.5 mmHg (7.6 kPa), bicarbonate was 30.6 mmol/l and base excess was 3.82 mmol/l. Mean serum IgG1 increased to 8.1 g/l after feeding colostrum. Several significant positive correlations were observed between post-absorptive serum protein, IgG1, IgM, gamma-glutamyltransferase (gamma GT) and D-xylose. Calves with either low serum albumin, high serum CK or low serum gamma GT before feeding tended to have less absorption of colostral protein. It was concluded that reduced absorption of IgG1 from colostrum is associated with hypercapnia in apparently healthy newborn calves.     

低、无毒农药防治花灌木主要刺吸式口器害虫

在查清天津市园林主要花灌木刺吸口器害虫桃粉蚜、绣线菊蚜、棉蚜和山楂红蜘蛛发生消长规律的基础上 ,确定了防治适期和结合点 ,筛选出 10 %吡虫啉、绿灵、蚧螨灵、 1. 8%齐螨素和花保5种低、无毒药剂 ,防效均达到 90 %以上。查出天敌 13种 ,并对优势种作了取食量调查     

苗期夜温对番茄畸形果发生的影响

试验表明番茄苗期低夜温不仅提高了畸形果发生率，而且也提高了畸形果平均级数和综合指数，并增加了畸形果的类型，同时乱形果在畸形果中所占的比例也增大。试验还认为：引起番茄畸形果大量发生的界限温度在大于６℃和小于１２℃的范围内，低温所需时间为幼苗２片子叶充分展开后１０～１６天，幼苗低温敏感期为２～４片真叶展开期。因此，番茄育苗期间应避免２～４片真叶展开期夜温低于１２℃。