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Smith W. D. and Christie M. G. 1978. Haemonchus contortus: lccal and serum antibodies in sheep immunised with irradiated larvae. International Journal for Parasitology8: 219–223. Two doses of Co60 irradiated Haemonchus contortus protected 9-month-old sheep against a challenge infection of 10,000 normal larvae. This resistance was associated with increased concentrations of IgG antibodies in the serum as well as IgA and IgG antibodies in the abomasal mucosa.  相似文献   

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Summary Chromatin from myeloma cells RPC 5 and ABPC 22, and from spleen and liver cells of immunized rats and mice, and mice bearing tumours, was fractionated into three parts: 0.35 M NaCl-soluble, 2 M NaCl-soluble and residual. The residual fraction from myeloma cells differed from that of immunized spleen cells, described previously as containing unique sequences (5), in that it has higher protein and DNA levels, lower DNase II sensitivity and lower template activity.  相似文献   

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The sheep biting louse ( Bovicola ovis ) feeds superficially on the skin of sheep but appears to stimulate an immune response. In this study we examined the association between louse infestation and serum and skin surface antibodies. Louse numbers were monitored on experimentally infested Polypay and Columbia ewes for two years and on their lambs in the second year. Serum and skin wash samples were tested for antibodies to soluble extracts of B. ovis , Stomoxys calcitrans and Musca autumnali s by enzyme linked immunosorbent assay (ELISA). In addition, the effects of skin wash extracts on B. ovis were examined in vitro .
The titre of anti- B. ovis antibodies in the serum did not differ significantly between infested and naive ewes. However, there was an increase in serum antibody titre which coincided with periods of high louse density in ewes with high louse counts. Infested lambs had higher serum antibody levels than naive lambs. Substantial cross reactivity was evident among extracts of the different insects.
Densities of lice on the ewes during population decline were negatively related to the titre of skin surface antibodies. Skin washings collected from sheep during B. ovis population decline reduced the number of louse progeny when incorporated into louse diet. These results indicate that B. ovis stimulates an immune response in sheep and suggest that compounds on the skin surface may play a role in the regulation of louse populations.  相似文献   

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The process of testicular maturation in relation to intrapuparial development was studied in the sheep nasal bot fly, Oestrus ovis L. (Diptera: Oestridae). After formation of the puparium during larval-pupal apolysis and the cryptocephalic pupal stage (approximately 24-72 h), spermatogonia had undergone mitotic divisions and sperm cysts had been formed. Five days after pupariation, spermatogonia transformed into primary spermatocytes during the phanerocephalic pupal stage, and secondary spermatocytes first appeared during the pupal-adult apolysis. Secondary spermatocytes began undergoing the second meiotic division by day 8 (transparent-eye pharate adult stage). By days 9 and 10, round spermatids were present and began to elongate by day 11. By day 12, the first bundles of tailed spermatozoa had appeared. By day 15 (the yellow-orange eye pharate adult stage), round, elongated, tailed and bundled spermatids were predominant and by day 17 differentiating spermatids occupied nearly 35% of the testicular cavity, and 60% was occupied by free sperm. By day 21 (the red-brown eye pharate adult stage), spermatozoa colonized the seminal vesicle. At emergence (approximately day 22), a complement of free sperm occupied the testis and the seminal vesicle, but groups of developing cells frequently remained in certain zones. Spermatogenesis was carried out after pupariation and spermiogenesis occurred during the pharate adult stage. After emergence, males possessed fully formed spermatozoa ready for ejaculation.  相似文献   

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Three sheep were infested 4 times with 100 Amblyomma americanum tick pairs and kept indoors until the natural termination of the infestations. Characteristics of the tick populations that show efficiency of feeding, fertility, and offspring development, and ELISA antibodies to tick salivary gland extracts were studied at each infestation. On average, female ticks fed on tick-naive sheep detached at 12.1 +/- 0.2 (mean +/- standard error) days, weighed 492 +/- 16.8 mg, engorged 40.7 mg per day, and 35% survived to detachment during the first infestation. During the fourth infestation, they detached at 17.3 +/- 0.8 days, weighed 321 +/- 14.4 mg, engorged 18.8 mg per day on average, and 23% survived to detachment. On average, oviposition of female ticks fed on tick-naive sheep started at 11.8 +/- 0.6 days of detachment, the egg mass weighed 236 +/- 13.2 mg, 43% of the female weight turned into eggs, and 89% of the ticks that detached survived to oviposition during the first infestation. During the fourth infestation, oviposition started at 15.1 +/- 0.5 days, the eggs weighed 103 +/- 9.9 mg, 13% of the tick weight became eggs, and 67% of the ticks survived to oviposition. On average, eclosion started at 35.4 +/- 0.9 days of oviposition and 83% of the egg batches hatched in the first infestation. During the fourth infestation, eclosion started on day 34.9 +/- 0.7, and 47% of the egg batches hatched. Anti-tick resistance was expressed as an inhibition of feeding, fertility, and offspring development.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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Structural changes were observed in filaments of Sarcocystis ovifelis infected sheep tongue myofibrils. In sarcocysts containing myofibrils, actin filaments and Z-disks, myosin filaments and M-line were seen destroyed. Protein bridges, uniting actin and myosin filaments into a joint complex (net), eventually become not visible, and as a result separate Z-disks and free filaments appear. Fibrils, referred to as leptomeric, have been first revealed between protrusions of the sarcocyst surface apparatus. These are striated filaments with periodic 100 nm striation of dark and light bands, made of thin and short 120-200 nm long filaments 5 nm in diameter. The genesis of leptomeric fibrils still remains obscure. In sarcocysts infected myofibrils these may be involved in metabolite transportation to the intercellular space and back.  相似文献   

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Some populations of the field cricket Teleogryllus oceanicusare parasitized by the phonotactic fly Ormia ochracea. Flieslocate crickets by their song and deposit larvae onto them.The larvae develop inside the cricket for 1 week before killingthe host upon emergence. The reproductive compensation hypothesispredicts that parasitized crickets should increase their reproductiveeffort during the initial stages of infestation to offset theloss of fitness resulting from their shortened life span. An alternative hypothesis predicts that parasitized crickets willdecrease reproduction, either because they are unable to reproduceor because selection acting on the parasitoid favors decreasedhost reproduction. In laboratory experiments, parasitized malecrickets had reduced reproductive effort (spermatophore production,calling, mating activity, and mass allocated to reproductivetissue) compared to unparasitized males. Parasitized males fedad libitum showed no evidence of allocating a greater proportionof their resources to reproduction. Parasitized and healthymales did not differ significantly in resting or maximal metabolicrates, although this may have been due to the substantial contributionof larval respiration to the metabolic rate of the host—parasitoidcomplex. These results are consistent with previous studiesand suggest that T. oceanicus males parasitized by O. ochraceado not increase their reproductive effort. We discuss potentialreasons that crickets do not increase reproductive effort inresponse to fly larvae and address difficulties in demonstratingaltered life-history patterns in response to parasitism.  相似文献   

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Insect immune defenses include encapsulation and the production of lysozymes and phenoloxidase. However, the highly mobile larvae of parasitoid Ormiine flies (Ormia ochracea) can evade initial encapsulation, and instead co-opt host immune responses to form a critical respiratory funnel connecting them to outside oxygen. Here we ask how field crickets (Teleogryllus oceanicus) respond immunologically to O. ochracea infestation. Host encapsulation and phenoloxidase play important roles in the formation of the respiratory funnel, so we hypothesized that decreases in these immune parameters during infestation may interfere with respiratory funnel formation and increase the likelihood of larval death. Encapsulation ability decreased after infestation with O. ochracea larvae, but phenoloxidase activity increased in both infested crickets and controls, whereas lysozyme activity decreased in infested crickets but remained constant in controls. Hosts with fewer established larvae showed greater decreases in encapsulation, and phenoloxidase activity was positively associated with the degree of larval respiratory funnel melanization. Differences between phenoloxidase and lysozyme activity in infested crickets are consistent with a trade-off within the immune system of hosts, and our results demonstrate the effects of a prior immune challenge on the ability to mount a subsequent response.  相似文献   

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A specific antibody against cytochrome c1 (pig heart mitochondria) has been obtained. It inhibits the electron transport of the respiratory chain in the intact mitochondria at the cytochrome c1 site of inner mitochondrial membrane ; but it has no effect on the isolated submitochondrial particles (inside-out inner mitochondrial membrane vesicles free of any outer membrane or outside-out inner membrane). Thus the topologic position of cytochrome c1 in the inner mitochondrial membrane is asymetrically lcoated on the outer side of the inner mitochondrial membrane. These results agree with our previous researches on ATP-ase and cytochromes b, c and a, indicating the location on the inner side for the first one, transmembranous for the last one, on the outer side for the others respiratory chain components. Thus the electron transport from cytochrome b to a takes place in the outer region of inner mitochondrial membrane and the transmembranous location of cytochrome-oxidase facilitates the transfer of the electrons to oxygen.  相似文献   

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Skin biopsies from larvae of Rattus norvegicus, experimentally infested with Dermatobia hominis (Linnaeus Jr) (Diptera: Cuterebridae), were processed for histopathological studies. Two days after infestation, the first-stage larvae (L1) were located deep in the dermis, surrounded by an inflamed area infiltrated predominantly by neutrophils. On the fourth day a thin necrotic layer could be seen close to the larvae, surrounded by large numbers of neutrophils, lymphocytes, macrophages with a few eosinophils and mast cells. A small warble was formed after the fourth day, increasing in size until the seventh day, when the L1 moulted to the second-stage larva (L2). The inflammatory process continued with increasing numbers of neutrophils, macrophages, lymphocytes, eosinophils and mast cells invading the area, as well as the proliferation of fibroblasts and endothelial cells and the appearance of a few localized haemorrhages. After 18-20 days, the L2 moulted to the third-stage larva (L3), when a few plasma cells could be seen in the inflamed area. At 25-30 days there was a reduction in the necrotic layer, as well as in the number of neutrophils and lymphocytes, although large amounts of eosinophils, plasma cells, and collagen fibres were seen. The L3 usually left the host after 30 days. Two days later, the larval cavity was reduced, mast cells infiltrated the region and collagen fibre production were increased. After 7 days, an intense infiltration of plasma cells and scattered necrotic areas could be seen. A scar formed after 10 days. This study showed the laboratory rat to be a suitable model for studies of D. hominis infestation.  相似文献   

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To evaluate the cross-reactivity between Hypoderma lineatum antigen and anti-Przhevalskiana silenus antibodies six protocols with different concentrations of antigen and different dilutions of sera and conjugate were applied. The highest cross-reaction between the H. lineatum antigen and the anti-P. silenus antibodies is given by 2 micrograms/ml of antigen concentration, 1:400 of serum and 1:10,000 conjugate dilution. The study on the kinetic development of antibodies in goats naturally infested by P. silenus and the natural course of infestation pointed out the existence of a good correlation between individual antibody kinetics and the natural evolution of the cycle of infestation. The highest antibody concentration may be registered from October through November, coinciding with the end of the migration fo the larvae inside the animal's body. In our condition, this period can be considered as a favorable sampling period for immunodiagnosis and immunoepidemiological studies of goat warble fly infestation.  相似文献   

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The kinetics of lithium in the serum, liver and brain of rats is described. The serum levels resembled those of man, whereas considerable quantitative differences were observed when comparing specific kinetic parameters. The brain level increased with the increasing doses, approaching the corresponding serum level. Concentration differences between different brain areas could be observed only after repeated administrations. Striatum, cortex and hippocampus showed significantly higher levels than the thalamus. The liver content remained low with increasing doses, and was below the brain level.  相似文献   

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