The effect of sire selection on the response of lambs to vaccination with irradiated Trichostrongylus colubriformis larvae

Dineen, J. K. and Windon, R. G. (1980). The effect of sire selection on the response of lambs to vaccination with irradiated Trichostrongylus colubriformis larvae. International Journal for Parasitology10: 189–196. Rams selected for responsiveness and unresponsiveness to vaccination with irradiated T. colubriformis larvae at an early age were mated to unselected random bred ewes. Progeny were vaccinated with 20,000 irradiated larvae at 8 and 12 weeks of age, given anthelmintic treatment at 16 weeks and challenged with 20,000 normai larvae at 17 weeks. The results, based on wether worm counts and ewe faecal egg counts, showed significant differences between responder and non-responder progeny. There was a significant correlation between worm counts and faecal egg counts of half-sibs from the same sire group. The occurrence of globule leucocytes was inversely related to worm burdens of wether progeny, however, no clear relationship was found with eosinophils. In vitro lymphocyte stimulation using T. colubriformis L₃ antigen, concanavalin A and lipopolysaccharide showed that statistically defined responder progeny, pooled from both responder and non-responder sire groups, gave higher responses than non-responder lambs after vaccination. The results confirm that genetically-determined factors are involved in the response of lambs to vaccination at an early age, and indicate that rapid genetic progress may be achieved in the type of mating usually carried out under fleld conditions.     

The role of thresholds in the response of lambs to vaccination with irradiated Trichostrongylus colubriformis larvae

A piecewise logarithmic model fitted to worm counts of ewe lambs vaccinated and challenged in pens with a range of doses of irradiated and normal Trichostrongylus colubriformis larvae respectively, indicated that the threshold for response to both vaccine (V₀ = 4400) and challenge dose is exceeded by 5000 larvae. Whereas response was vaccine dose dependent, it was independent of challenge dose.Ram lambs vaccinated at low dose levels were as resistant against challenge as ewe lambs, but by contrast, failed to show increased protection after vaccination with high doses of irradiated larvae.Serum titre of antiworm complement-fixing antibodies at the time of challenge also indicated that ram lambs were less responsive immunologically than ewe lambs following vaccination at the higher dose levels.A field study showed that response to vaccination was only apparent after transfer of the sheep to heavily contaminated pastures, suggesting that previous exposure of the vaccinated animals to the low dose of infective larvae available on a lightly contaminated pasture constituted a challenge which was below the threshold.     

The response of lambs to vaccination and challenge with Trichostrongylus colubriformis: Effect of plane of nutrition on,and the inter-relationship between,immunological responsiveness and resistance

Wagland B. M., Steel J. W., Windon R. G. and Dineen J. K. 1984. The response of lambs to vaccination and challenge with Trichostrongylus colubriformis: effect of plane of nutrition on, and the inter-relationship between, immunological responsiveness and resistance. International Journal for Parasitology14: 39–44. Merino lambs weaned at 8 weeks of age were fed either ground and pelleted (high plane, HP) or chopped (low plane, LP) lucerne hay ad libitum to achieve an approximate 2-fold difference in liveweight gain. When aged 17 and 21 weeks, 15 of the 20 lambs in each diet group were vaccinated with 80,000 irradiated T. colubriformis larvae. At 25 weeks, vaccinated and unvaccinated lambs were treated with anthelmintic and one week later challenged with 30,000 normal larvae. Four weeks after challenge the animals were killed for worm counts. After vaccination HP lambs had higher titres of antibodies to the parasite and after challenge had lower worm egg outputs, and lower worm burdens than LP lambs. Immunological responsiveness (serum titre of complement-fixing antibodies against worm antigen) and manifestations of resistance (eggs produced per female worm per day and percent protection calculated from worm counts) were significantly correlated within dietary groups. Percent protection and egg production per female worm were highly correlated (r = ?0.81) in individual animals pooled over dietary groups, suggesting that both manifestations of resistance respond to essentially the same immunological mechanism. Failure to obtain significant correlation between weight gain pre-vaccination and immunological and resistance parameters indicated that animal production and resistance to infection are not genetically linked. Negative correlation of weight gain during the vaccination period with serum antibody titre at challenge suggests that the developing immune response competes with weight gain for limited physiological resources of the animal.     

The effect of osmotic stress on behaviour and water content of infective larvae of Trichostrongylus colubriformis

The role of the cuticle and sheath in the water dynamics of the infective larvae of Trichostrongylus colubriformis under osmotic stress and the effect of osmotic stress on behaviour have been investigated. In hypotonic solutions larvae lose the activity response to mechanical stimulation and there was also some increase in coiling. Larvae can regulate their water content in hypotonic solutions but lose water slowly in hypertonic solutions. Removal of the sheath by exposure to sodium hypochloritc or to a ‘natural’ stimulus had little effect on the water dynamics of infective larvae. The sheath thus appears to be freely permeable to water when hydrated whereas the cuticle has a very restricted permeability.     

The initiation of coiling behaviour prior to desiccation in the infective larvae of Trichostrongylus colubriformis

Wharton D.A.1981. The initiation of coiling behaviour prior to desiccation in the infective larvae of Trichostrongylus colubriformis. International Journal for Parasitology11: 353–357. Infective larvae of Trichostrongylus colubriformis coil during the evaporation of water films. Decreasing the depth of the liquid film does not initiate coiling but enclosure in capillary tubes of similar diameter to the track width of actively swimming or crawling larvae results in a marked stimulation of coiling behaviour. It is suggested that larvae coil in response to the progressive restriction of lateral movement in an evaporating water film. The behavioural flexibility of the infective larvae of T. colubriformis maximizes both their survival and their chances of infection.     

Histamine and leukotriene concentrations in duodenal tissue and mucus of lambs selected for high and low responsiveness to vaccination and challenge with Trichostrongylus colubriformis

Lambs selectively bred for high responsiveness or low responsiveness to vaccination with irradiated Trichostrongylus colubriformis were vaccinated and challenged. Duodenal tissue histamine concentrations in both high and low responder lambs were lower at 3 days than at 28 days after challenge. At 3 days after challenge, histamine concentrations were higher in both male and female high responder lambs than in low responder lambs whereas at 28 days concentrations were increased only in high responder females. At 3 days after challenge, histamine concentrations were generally lower in mucus than in tissues, but levels were again higher in mucus from high responder groups. In duodenal tissue at 3 days after challenge, leukotriene C₄ and B₄ concentrations were similar in high and low responder animals. At the same time, concentrations of both leukotrienes were higher in mucus than in tissues, with high responder female lambs having the highest concentration. It is suggested that increased levels of histamine and leukotrienes in mucus and tissue are associated with larval rejection or exclusion.     

The effect of acquired resistance on adult worms of Trichostrong ylus colubriformis in lambs

Dineen J. K. and Windon R. G. 1980. The effect of acquired resistance on adult worms of Trichostrongylus colubriformis in Lambs. International Journal for Parasitology10: 249–252. Wether lambs were classified as either responders or non-responders to vaccination and challenge with Trichostrongylus colubriformis. Worms recovered from these animals and unvaccinated controls were measured, eggs in utero counted and sex ratios (male/female) were determined for individual burdens. The results showed that all three parameters were reduced in responder lambs compared with non-responder and unvaccinated lambs and were positively correlated with worm counts in responder lambs whereas they tended to be negatively correlated with worm counts in non-responders and unvaccinated animals.These various effects of resistance on parasite development in responder lambs may be due to the action of endogenous inflammatory agents generated immunologically. On the other hand negative correlation between developmental parameters and worm burdens in non-responders and unvaccinated lambs suggests that development of parasites in heavy infections may be restricted by competition for a limiting physiological, spatial or nutritional resource of the host.     

The response of lambs to vaccination at weaning with irradiated Trichostrongylus colubriformis larvae: segregation into 'responders' and 'non-responders'

Dineen J. K., Gregg P. and Lascelles A. K. 1978. The response of lambs to vaccination at weaning with irradiated Trichostrongylus colubriformis larvae: segregation into ‘responders’ and ‘non-responders’. International Journal for Parasitology8: 59–63. Groups of colostrum fed and colostrum deprived lambs were vaccinated with irradiated Trichostrongylus colubriformis larvae at weaning (3 months) and challenged with normal infective larvae. As there was no significant difference between the worm counts of these groups after challenge, it was concluded that the failure of lambs, generally, to respond to vaccination as vigorously as mature sheep, was not due to ‘feed-back inhibition’ of the immune response by the action of maternal antibody.However the results showed that the lambs segregated into ‘responders’ and ‘non-responders’. The mean worm count of responders was 1560 whereas for non-responders this was 24,340. A responder was defined as an animal whose worm count was less than the lower limit of the 99 % confidence interval of unvaccinated controls. These results suggest that genetically-determined factors play an important role in the responsiveness of lambs to vaccination.Whereas counts of globule leucocytes in duodenal tissues were negatively correlated with worm counts (i.e. positively correlated with resistance), counts of both eosinophils and neutrophils were positively correlated with worm counts. These findings suggest that either globule leucocytes are involved in the resistance mechanism, or they are by-products of cellular events involved in resistance. On the other hand it is unlikely that either eosinophils or neutrophils are involved in the mechanism of resistance.     

The response of sheep to parenteral vaccination and immunizing infections against the abomasal nematode, Haemonchus contortus

Adams D. B., Beh K. J. and Davies H. I. 1982. The response of sheep to parenteral vaccination and immunizing infections against the abomasal nematode, Haemonchus contortus. International Journal for Parasitology12: 445–449. Subcutaneous injection of relatively large amounts of unfractionated homogenates of adults plus infective larvae of Haemonchus contortus emulsified in complete Freund's adjuvant produced a degree of protective immunity when challenge infection was given eight weeks after the first or only dose of vaccine. In an attempt to improve acquired immunity, parenteral vaccination was either followed or preceded by a short immunizing infection with H. contortus, which was terminated by anthelmintic before patency. This treatment aimed at stimulating general responsiveness to worm antigens and invoking mucosal immunity in the abomasum. Disparate results were obtained; immunizing infections either increased immunity or made sheep more susceptible to challenge infection. In this latter situation, the unresponsiveness associated with primary infection with H. contortus may have been increased.     

The effect of F0 inhibitors on the Vibrio alginolyticus membrane ATPase

The inhibition of membrane ATPase from the marine alkalotolerant bacterium Vibrio alginolyticus by DCCD, triphenyltin and venturicidin was studied. DCCD proved to be an irreversible inhibitor, while venturicidin and triphenyltin produced a reversible inhibitory effect. The DCCD-binding proteolipid was identified in the membrane preparations. The effect of the inhibitors on ATPase activity and ATP-dependent Na⁺-transport in V. alginolyticus subcellular vesicles is discussed.     

The use of a water-in-oil adjuvanted vaccine in an attempt to immunize lambs against Taenia ovis cysts in the presence of maternal antibody

An attempt was made to actively immunize lambs during the period when they had maternally-acquired antibody, so that there would be no time when lambs were susceptible to Taenia ovis infection. A slow-release water-in-oil adjuvanted vaccine containing T. ovis oncosphere products was used. Half the ewes were vaccinated prior to parturition and lambs were vaccinated at approx. 5 weeks of age. At necropsy, after challenge infection, vaccinated lambs had a mean of 39 cysts, compared to 131 in unvaccinated control lambs (p < 0.05), but there was no effect on development or survival of the established cysts. The presence of passively-acquired anti-oncosphere antibody at the time of vaccination did appear to influence the degree of antibody response, and the level of protection induced. However, there was no correlation between levels of antibody at vaccination and levels of protection induced, because of the considerable individual variation between lambs. In non-vaccinated control lambs, the serological response to challenge infection was also highly variable.Some vaccinated lambs developed a strong primary serological response and were mostly (5/7) fully protected. Lesser degrees of primary response in other lambs did not fully protect. All vaccinated lambs gave a rapid secondary response after challenge, but it was too late to be protective. The immunization procedure, although effective in some lambs and partially effective in most, cannot be recommended.     

The action of prostaglandin E2 and F1α on myocardial ischaemia-infarction arrhythmias in the dog

Prostaglandin E₂ and F_1α infusions have been tested for their ability to reduce the arrhythmias associated with occlusion of the left descending coronary artery in the anaesthetised dog. At 1 μg/kg/min both PGs reduced the incidence of premature ventricular contractions occurring during 25-min occlusions, while not reducing the incidence of ventricular fibrillation occurring on occlusion release. When infused for 5-min periods at 1 to 16 μg/kg/min, neither PGE₂ nor PGF_1α effectively reduced the frequency of ventricular arrhythmias occurring 24 hr after a permanent coronary occlusion.     

The effect of intra-uterine prostaglandin F2α on corpus luteum function in the human

Prostaglandin F_2α (PGF_2α) was administered via a Foley catheter over a 12 hour period to 8 healthy volunteers awaiting laparoscopic sterilisation. The amount of PGF_2α infused varied between 500 μg and 2000 μg every 2 hours for 6 doses. Plasma progestins and oestradiol 17β, and urinary estrogens and pregnanediol were assayed throughout the study period.There was no evidence of luteolysis in any patient although vaginal bleeding of varying duration occurred in all women within 36 hours of administration of PGF_2α.     

The effect of indomethacin on the biosynthesis and metabolism of prostaglandin F2α in man

Healthy volunteers received 60 μg of [8,10,10-²H₃] PGF_2α by intravenous infusion both before and during a course of treatment with indomethacin (200 mg/day). Excretion of deuterated 5α, 7α-dihydroxy-11-ketotetranor-prostane-1, 16-dioic acid in urine was quantified by GC-MS using a reverse stable isotope dilution procedure. Indomethacin was found to have no detectable effect on the metabolism of the labelled PGF_2α whereas output of the endogenous metabolite was markedly reduced by the effect of the drug on prostaglandin biosynthesis.     

无机磷影响叠氮钠对ATP合成酶合成活性的抑制

利用ADP和放射性磷直接合成ATP的方法,研究了无机磷(P_i)和叠氮钠对猪心线粒体ATP合成酶（F₁F_O-ATPase）ATP合成活性的影响.结果发现无机磷除作为合成ATP的底物参与F₁F_O-ATPase的合成反应外,还对F₁F_O-ATPase的合成活性呈现抑制作用,在1 mmol/L ADP存在时,随着P_i浓度由0.01～10 mmol/L增加,抑制合成作用越来越强.与叠氮钠在低浓度时(小于1 mmol/L)只抑制ATP水解,不影响ATP合成的观点不同.实验结果显示0.1 mmol/L叠氮钠表观激活F₁F_O-ATPase的ATP合成活性,且激活程度与反应体系中所加P_i的浓度呈负相关.当固定P_i浓度（0.1 mmol/L）后,随着叠氮钠浓度的增加表观激活程度也在变化,叠氮钠与磷浓度相等时表观激活程度最大,直至叠氮钠浓度接近0.5 mmol/L时,开始呈现表观抑制现象,叠氮钠浓度高于1 mmol/L之后,就出现解偶联现象.     

The effect of PGE2 and PGF2α on the response of guinea pig myometrium to adenine nucleotides in vitro

Prostaglandins E₂ and F_2α potentiate contractile effect induced by adenine nucleotides ATP, ADP and AMP in guinea pig myometrium in vitro. Prostaglandins and nucleotides were added to the organ bath in minute concentrations which have been proved ineffective or slightly contractile when both groups of substances were administered separately. The data of the present work, together with our previously published studies (9,10,13), where the action of exogenous adenine nucleotides, NAD and adenosine on rabbit's jejunum in vitro has been proved antagonistic to the contractile effect of various prostaglandins, suggest that prostaglandins and adenine nucleotides appear to block selectively or augment each other's action on various organs. The initial hypothesis that there is a regulatory correlation between endogenous prostaglandins and the function of purinergic nerves also is reinforced.     

水稻杂种F1结实率与亲本程氏指数差异和同工酶遗传距离的关系及其预测研究

以4个籼粳测验种做母本按NCII(4×90)设计配置的360个杂交F1组合为材料,研究亲本的程氏指数差异(ID)、同工酶遗传距离(GD)与杂种F1结实率的关系.结果显示ID、GD与杂种F1结实率呈极显著负相关(r=-0.540,p＜0.01;r=-0.316,p＜0.01),但决定系数不高,分别是0.2916、0.0999.D、GD与F1结实率的相关性受父本和母本影响,其中对非广亲和品种测交F1结实率的预测效果较好,对广亲和品种及南京11的测交F1的预测则无效.因此,在利用ID和GD对水稻杂种F1结实率进行预测时,宜在一定的亲本类型之间进行,ID比GD的预测效果更好.     

The effect of prostaglandin E2 on the cardiovascular response to angiotensin II in pregnant rabbits

The rise in arterial blood pressure in response to angiotensin II was studied in the last third of pregnancy in rabbits. The response was compared with that of pregnant rabbits during infusion of prostaglandin E₂ and F_2α. Prostaglandin E₂ significantly diminished the rise in diastolic pressure in response to angiotensin II. Prostaglandin F_2α did not alter the response. Intravenous indomethacin elevated the blood pressure and caused an absolute increase in the pressor response. It did not mediate a change in the percentage rise in blood pressure in response to angiotensin II.     

The response of stomata to CO2 relates to its effect on respiration and ATP level

External ATP enhanced stomatal opening of Commelina communis L. differently from EDTA. ATP was more effective in opening stomata than EDTA, when both were applied in amounts yielding equivalent free Ca²⁺ concentration. The stimulation by ATP depended upon its de-phosphorylation and was not due to the P₁ released. Hence an energetical contribution of external ATP appears possible. Increase in CO₂ concentration increased the stimulation of stomatal opening by ATP and diminished the internal ATP level, ATP/(ADP+AMP) ratio and respiration rate.     

Analysis of a silkworm F1 hybrid with yellow cocoon generated by crossing two white-cocoon strains: Further evidences for the roles of Cameo2 and CBP in formation of yellow cocoon

In this report, we examined the gene expression related to carotenoid transport for a silkworm F₁ hybrid with yellow cocoon generated by crossing two white-cocoon strains, Qiubai and 12-260. Our results showed that, in Qiubai, Cameo2, a transmembrane protein gene belonging to the CD36 family genes, was expressed normally in the silk gland, but no intact carotenoid-binding protein (CBP) mRNA (only the truncated CBP mRNA) was detected in the midgut. In 12-260, we detected the intact CBP mRNA expression in the midgut, but no Cameo2 expression in the silk gland. Regarding the F₁ hybrid from crossing Qiubai and 12-260, both Cameo2 and intact CBP mRNA expressed normally in the silk gland and midgut. HPLC detection confirmed that in the F₁ hybrid the carotenoids could be absorbed from dietary mulberry leaves through the midgut and transferred to silk gland via the hemolymph, which eventually colored cocoons into yellow. We also identified four CBP mRNA isoforms expressed in the midgut of the F₁ hybrid, subsequently named as variants 5–8. Our results provide further evidences for the roles of Cameo2 and CBP in the formation of yellow cocoon of silkworm.