Influence of thymic preparations on the result of experimental infection with Taenia crassiceps (Zeder, 1800) in ICR mice

Thymalin (Thymarin) and T-activin--thymic preparations of polypeptidic character--were used for influencing the parasitic infection in a model system mouse--Taenia crassiceps. A single subcutaneous application of 100 micrograms of Thymalin per mouse at the day of infection resulted in a decrease (by 54.9%) in the number of cysticerci in peritoneal cavity of experimental mice compared with the controls. Administration of Thymalin with T. crassiceps larval homogenate at various intervals before and after infection resulted in a statistically significant increase of the level of specific antibodies in the serum of infected mice, this increase, however, did not correlate with the corresponding protective effect. Immunosuppressant azathioprine, injected subcutaneously from 7th to 3rd day preceding infection at a dose of 100 micrograms resulted in a significant increase in the number of T. crassiceps larvae in the peritoneal cavity of experimental mice compared with the controls (by 48.7%). T-activin, injected subcutaneously to mice, immunosuppressed by azathioprine, led to a restoration of resistance of mice to T. crassiceps infection. Subcutaneous application of T-activin alone had a significant protective effect (decrease in cysticerci number by 53.7% in comparison with the controls). Correlation of the level of specific antibodies in the serum of infected mice, value of spleen index and number of T. crassiceps cysticerci in peritoneal cavity of mice was not detected.     

Chalone-like inhibition of DNA synthesis in helminths

Chalone-like inhibitory activity was found in extracts from tissues of Taenia crassiceps cysticercus and tissues of adult Ascaris suum. The inhibitory effects were partially species nonspecific: The extracts from T. crassiceps larvae inhibit both T. crassiceps and Mesocestoides corti larvae DNA synthesis. Extracts from A. suum, however, inhibit only T. crassiceps. Besides them, the inhibitory factor from mouse brain inhibits both T. crassiceps and M. corti DNA synthesis. When the inhibitory factor from A. suum was applied 4 times during 24-hr culture (at 6-hr intervals), the inhibitory effect was decreased.     

Characteristics of malic enzyme from the cysticerci of Taenia crassiceps (Zeder, 1800)

Kinetic parameters of partly purified malic enzymes (NADP+: L-malate oxidoreductase (decarboxylating) EC 1.1.1.40) from the cytoplasm and mitochondria of Taenia crassiceps cysticerci were compared. The cytoplasmic malic enzyme differed from the mitochondrial malic enzyme in the K'M for malate; other studied properties were identical. The chromatographies of both the cytoplasmic and mitochondrial enzymes were identical. They exhibited a hyperbolic dependence of the activity on malate concentration, sigmoidal kinetics was not observed. The effects of succinate and fumarate known as positive modulators of the activity of malic enzymes from other sources were not observed either in cytoplasmic or mitochondrial enzymes from T. crassiceps. It was found that the two enzymes can be partly inhibited by ATP. Molecular weight of the malic enzyme from T. crassiceps cysticerci was determined by chromatography on Sephadex G-200 (Mw = 116,700) and a four-step purification of the enzyme was performed. The properties of malic enzymes from the cytoplasm and mitochondria of T. crassiceps are compared with those of the malic enzymes from other parasitic worms and higher organisms.     

Experimental infection of immunocompetent and immunodeficient mice with Encephalitozoon cuniculi

An experimental infection with the microsporidian Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 was studied using a model of immunocompetent BALB/c mice and immunodeficient SCID mice. The course of infection after intraperitoneal inoculation of E. cuniculi spores was evaluated using the presence of spores in peritoneal macrophages as a criterion. First significant decrease in the proportion of infected cells was recorded on day 9 post infection (p.i.) in BALB/c mice. From day 14 p.i. no spores were observed in macrophages from BALB/c mice, while the number of infected macrophages from SCID mice increased until the death of the mice. The natural killer (NK) cell activity of mouse splenocytes was compared with the production of interferon gamma (IFN-gamma) by these cells. While in BALB/c mice NK activity peaked on days 9 and 14 p.i., in SCID mice the marked increase of NK activity was recorded close before death of mice, on day 21 p.i. in correlation with the production of IFN-gamma. Production of specific antibodies was demonstrated from day 9 p.i. in sera from BALB/c mice. It is concluded that intraperitoneal infection of SCID mice with spores of E. cuniculi results in the marked increase in the number of peritoneal exudate cells and in the percentage of infected cells close before death of mice. Neither high activity of NK cells nor increased production of IFN-gamma are sufficient for the recovery of SCID mice from an E. cuniculi infection.     

Dependency of resistance of mice immunized against Taenia crassiceps on the dose of soluble antigen

Mice immunized with a single dose (1.25-40 micrograms/mouse) of soluble antigen from Taenia crassiceps cysticerci developed a 62.9-85.0% resistance. Maximum effect was achieved in the groups immunized with 40 micrograms and 20 micrograms of antigen. The dose of 5 micrograms induced the lowest number of successful infections (28.6%), but the mean number of surviving larvae was higher than in the above groups.     

Levamisole--biological response modifier in Taenia crassiceps--mouse experimental system

Levamisole, a common anthelminthic preparation, was used for the modification of the immune response of mice to vaccination with soluble antigen from Taenia crassiceps. The combination of antigen with Levamisole significantly increased the immunogenic effect of the antigen. Metacestodes survived in 16.7% after one dose and in 42.9% after two doses of Levamisole. The percentage of resistance was 97.7% and 67.8%.     

The dynamics of eosinophilia in concurrent infections with Trichinella spiralis Owen, 1835 and Toxascaris leonina Linstow, 1909

The concurrent infection with larvae of Trichinella spiralis and eggs of Toxascaris leonina was studied under various conditions using 75 male white mice. The changes in content of eosinophilic leucocytes in the blood, as well as the total number and distribution of larvae of both parasites in different body tissues were demonstrated. The primary infection with Toxascaris leonina caused an increase in the number of eosinophilic leucocytes from day 4 p.i., whereas the infection with Trichinella spiralis larvae induced an increase only from day 7 p.i. An antagonism was observed between the two parasite species: the primary infection with T. leonina led to a decrease in the total number of muscle larvae of T. spiralis, and, vice versa, the primary infection with T. spiralis suppressed the development of T. leonina.     

Effect of vitamins on Trichinella spiralis Owen, 1835 infection in mice

The effects of vitamins A, B complex, E, and ADE on the body weight, eosinophilia, intensity of infection and distribution of T. spiralis larvae were studied in mice. The greatest loss of weight followed after the application of vitamins B complex and E. An increased eosinophilia appeared in the majority of infected mice since day 7 p.i., reaching the maximum on day 21 p.i. In mice receiving vitamins B complex, A, and ADE, the increased eosinophilia was observed still on day 60 p.i. The highest levels of eosinophilia occurred after the application of vitamins B complex and E, which was directly proportional to the intensity of infection. The lowest intensity of infection was recorded in mice receiving vitamin A. Though there were great differences between individual mice, the greatest number of larvae were localized in the diaphragm and left masseter.     

钾肥种类和施钾时期对油葵产量及品质的影响

为分析钾肥种类和施钾时期对油葵产量以及品质的影响,选取油葵杂交品种陇葵杂3号,采用2因素3水平（2个钾肥种类：氯化钾（F1）、硫酸钾(F2);3个施钾时期：全部种前基施（T1）、 50% 基施+50%现蕾期追施（T2）、 25%基施+50%现蕾期追施+25%花期追施（T3））随机区组试验设计,于2014-2016年在甘肃省景泰条山农场进行田间试验。结果表明：KCl和K₂SO₄这两个钾肥品种的盘径、千粒重、粗脂肪含量、产油量、亚麻酸含量间没有明显的差异。与施用K₂SO₄相比,施用KCl的产量在2014年显著增加,F1T2的产量较F2T2增加了4.96%,F1T3较F2T3增加了4.06%。出仁率、油酸含量在2015年和2016年显著增加,F1T1的出仁率较F2T1在2015年和2016年分别增加了1.50%、2.99%,F1T2的出仁率较F2T2在2015年和2016年分别增加了1.76%、19.7%;2015年F1T2的油酸含量较F2T2增加了5.92%;2016年F1T3的油酸含量较F2T3增加了9.09%。粗蛋白含量在2014年和2016年显著降低,F2T3的粗蛋白含量较F1T3在2014年和2016年分别增加了9.95%、8.87%。粗蛋白产量在2016年显著降低,F2T3的粗蛋白产量在2016年较F1T3增加9.29%。亚油酸含量在2015年和2016年显著降低, F1T3的亚油酸含量较F2T3在2015年和2016年分别增加了3.17%和3.03%。施钾时期对油葵的盘径、亚麻酸含量没有显著影响,但对油葵的千粒重、出仁率、产量、蛋白质含量、蛋白质产量、粗脂肪含量、产油量、油酸、亚油酸影响显著。钾肥的最佳施用时期为基施。油葵产量与盘径、千粒重、出仁率均有显著的正相关关系,油酸和亚油酸之间存在负相关关系。     

Attenuation of Schistosoma mansoni cercarial infectivity to albino mice by methanol extract of some plant species

This study elucidates the activity of certain plants’ methanol extract: Anagallis arvensis, Solanum nigrum (green fruits), Chenopodium ambrosioides, Calendula officinalis and Sesbania sesban, on the infectivity of S. mansoni cercariae to albino mice. Then, some parasitological parameters, e.g. the worm load/mouse, number of ova/g tissue in liver and intestine and the developmental stages of ova in the small intestinal wall (Oogram) of infected mice were determined. In addition, certain biochemical parameters of serum from infected mice (total protein, albumin, the activities of AlT, AsT, AcP and AkP enzymes) were, also, recorded.The results showed that exposure of S. mansoni cercariae for 30 min to the tested plants’ methanol extract before mice infection has a higher suppressive effect on their infectivity to albino mice then those exposed to this extract during mice infection. The number of worms recovered/infected mouse and the number of ova/g tissue from liver and intestine of mice groups infected with cercariae exposed to the tested plants’ methanol extract either pre- or during mice infection were less than those of infected control groups (e.g. the reduction rates of worm load/mouse and number of ova/g tissue in the intestine were 46.1% and 76.8%, respectively, for mice infected with cercariae exposed to 5 ppm of A. arvensis during mice infection).The results, also, indicated that exposing S. mansoni cercariae to methanol extract of the experimental plants either pre- or during mice infection reduced the activities of the enzymes AlT, AsT, AcP and AkP that were elevated in mice infected with untreated cercariae, meanwhile, the concentrations of total protein and albumin were increased in the serum of mice infected with these treated cercariae in comparison with those of mice group infected with untreated cercariae.     

Purification and properties of cytoplasmic malate dehydrogenase from Taenia crassiceps (Zeder, 1800) cysticerci

Malate dehydrogenase (L-malate: NAD oxidoreductase, EC 1.1.1.37) from the cytoplasm of Taenia crassiceps cysticerci was purified and the basic kinetic parameters of this enzyme were determined. The pH optimum range of enzyme reaction was found to be very wide: 8.8-11.0 for malate oxidation and 6.0-8.5 for oxaloacetate reduction. KM values for oxaloacetate, malate, NAD, and NADH were 7.8.10(-5) M, 1.4.10(-4) M, 1.2.10(-4) M, and 6.10(-5) M, respectively. Malate dehydrogenase activity was inhibited by malate excess. Molecular weight of malate dehydrogenase was 70,800. A comparison of the data obtained with those from other organisms including vertebrates showed that the cytoplasmic malate dehydrogenase from T. crassiceps is almost identical with the enzymes from other sources in its kinetic and regulatory properties, as well as in its molecular weight.     

Antagonism of Nutrient-Activated Conidia of Trichoderma harzianum (atroviride) P1 Against Botrytis cinerea

ABSTRACT The effect of preliminary nutrient activation on the ability of conidia of the antagonist Trichoderma harzianum (atroviride) P1 to suppress Botrytis cinerea was investigated in laboratory, greenhouse, and field trials. Preliminary nutrient activation at 21 degrees C accelerated subsequent germination of the antagonist at temperatures from 9 to 21 degrees C; at >/=18 degrees C, the germination time of preactivated T. harzianum P1 conidia did not differ significantly from that of B. cinerea. When coinoculated with B. cinerea, concentrated inocula of preactivated but ungerminated T. harzianum P1 conidia reduced in vitro germination of the pathogen by >/=87% at 12 to 25 degrees C; initially quiescent conidia achieved this level of suppression only at 25 degrees C. Application of quiescent T. harzianum P1 conidia to detached strawberry flowers in moist chambers reduced infection by B. cinerea by >/=85% at 24 degrees C, but only by 35% at 12 degrees C. Preactivated conidia reduced infection by >/=60% at 12 degrees C. Both quiescent and preactivated conidia significantly reduced latent infection in greenhouse-grown strawberries at a mean temperature of 19 degrees C, whereas only preactivated conidia were effective in the field at a mean temperature of 14 degrees C on the day of treatment application. An antagonistic mechanism based on initiation of germination in sufficiently concentrated inocula suggests that at suboptimal temperatures the efficacy of Trichoderma antagonists might be improved by conidia activation prior to application.     

Dynamics of the IgG3 responses following immunisation of BALB/c mice with somatic and excretory/secretory antigens from various Trichinella species

Comparison of the dynamics and antigen recognition profiles of IgG3 following immunisation with larval crude extracts (LCE) and excretory-secretory (ES) products from muscle larvae of different species of Trichinella (T. spiralis, T. nativa, T. britovi, T. nelsoni and genotype T6) was made in BALB/c mice. High levels of gG3 response were obtained in ELISA following immunisation with LCE from all species with maximum levels achieved between days 59 and 64 post-immunisation (p.i.) and maintained up to the limit of the observation (day 164). Antigen recognition profiles as measured by western-blot showed dense and numerous bands in the range 45-64 kDa that were consistent from week 5th with variation in epitope recognition among the different species. Following immunisation with ES antigens a significant decrease in IgG3 response was observed for all species especially for T. nativa in comparison to LCE. Antigen recognition on ES antigens showed three main bands in the range of 45-60 kDa for all species excepting T. nelsoni and T. britovi where an additional band was also present. These results clearly show that IgG3 epitopes are more abundant in somatic (LCE) than in ES products of Trichinella muscle larvae and that quantitative as well as qualitative variations exist among different species.     

Effects of leaf wetness duration and temperature on infection efficiency, latent period, and rate of pustule appearance of rust in alfalfa

ABSTRACT Dew and growth chamber tests were conducted on the alfalfa cultivar Ranger to determine the effect of duration of leaf wetness and temperature on several components of the alfalfa rust (Uromyces striatus) monocycle. Duration of leaf wetness and temperature both had significant effects on pustule development. Infection efficiency (number of alfalfa rust pustules per leaf) increased linearly as duration of leaf wetness was increased from 4 to 24 h after inoculation. There was an inverse linear relationship between temperature and infection efficiency as indicated by the slope (-5.73) of the regression line relating the number of pustules per leaf to increasing temperatures between 17.5 and 28 degrees C. Infection efficiency was approximately 20 times greater at 17.5 degrees C than at 28 degrees C. Inoculated alfalfa plants exposed to constant temperatures of 15, 18, 21, 24, 27, or 30 degrees C after an initial 24-h leaf wetness period (19 degrees C) did not significantly affect infection efficiency (P 相似文献   

Rheumatoid factor-like IgM in Plasmodium berghei (Apicomplexa: Haemosporida) infections of BALB/c mice

Groups of female BALB/c mice infected by intravenous injection with 50 erythrocytes containing Plasmodium berghei Vincke et Lips, 1948 were sacrificed on days 3 through 12 after infection. Rheumatoid factor-like IgM (RF-IgM) and parasite-specific IgG levels were determined by enzyme-linked immunosorbent assay in serum specimens and in culture medium removed from spleen cell cultures established at sacrifice. All four mouse IgG subisotypes were recognized by RF-IgM molecules induced by Plasmodium berghei infection, and in this regard, the parasite-induced RF-IgM response resembled that induced by lipopolysaccharide polyclonal activation. Plasmodium berghei infection resulted in a biphasic RF-IgM response, with infected animals demonstrating significantly increased levels of RF-IgM early in the infection and significantly decreased levels late in the infection, compared to uninfected control mice. The decreased levels of RF-IgM observed late in infection correlated with increasing parasitaemia levels, and were primarily due to a decrease in RF-IgM specific for mouse IgG2a. Late infection levels of RF-IgM specific for IgGI, IgG2b, and IgG3 were not significantly different from those of control animals.     

The Use of a Radioimmunosorbent Assay for Botrytis cinerea1

A radioimmunosorbent assay was developed for Botrytis cinerea which can be used to detect as little as 100 ng of Botrytis mycelium (dry weight). Of 22 fungi tested in the assay, all significant reaction was restricted to members of the Sclerotiniaceae. No reaction was obtained with representative isolates of Aspergillus, Alternaria or Peiticillium. Other Botrytis species gave the most reaction relative to B. cinerea. and related genera such as Monilinia and Sclerotinia yielded small reactions. The assay can be used to detect fi. cinerea infection of grape berries when as little as 0.1 % of homogenate from infected fruit is mixed with homogenate from sound fruit to simulate a minor infection. The assay of free run juice from various lots of grapes was highly correlated with visual assessments of infection in the field. Pursuant to various theories concerning bloom time infection, the assay was used to analyse the B. cinerea content of immature berry tips and floral debris; however, no evidence of such colonization was obtained.     

Study of cytochromes from mitochondria of Taenia crassiceps (Zeder, 1800) cysticerci

Cytochrome components of mitochondria from Taenia crassiceps cysticerci were studied by difference spectrophotometry (at 22 degrees C). The following concentrations of cytochromes (expressed in nmol X mg-1 protein) were found: 0.132 (cytochrome b), 0.083 (cytochrome c), and 0.0856 (cytochrome aa3). The participation of aerobic processes in the general production of energy is discussed and the results are compared with literary data obtained in cytochrome studies of other parasitic worms.     

Humoral intestinal immunity against Encephalitozoon cuniculi (Microsporidia) infection in mice

Three strains of mice, BALB/c, IL-12 knock-out (KO) and INF-gamma knock-out, were chosen as an experimental model for the study of intestinal immunity induction against Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 infection. Mice were infected perorally with 10(7) spores and re-infected with the same dose 70 days after the first infection. The anti-E. cuniculi IgA, IgG and IgM responses in sera and extracts of stool samples were determined by ELISA. Results have shown specific antibody production in the sera and intestinal secretions of all three strains of mice induced orally by E. ciniculi spores. BALB/c mice developed a stronger humoral immune response than IL-12 KO mice. The lowest antibody response developed in INF-gamma KO mice that succumbed to the infection within 28 days post infection.     

Contribution to the knowledge of aerobic processes in Taenia crassiceps larvae (Zeder, 1800)

Respiration of homogenates and isolated mitochondria of T. crassiceps larvae was measured. Respiration (about 70%) could be inhibited by cyanide, indicating that an important part is played by classical respiratory chain. When succinate was used as substrate, relatively low respiratory rates were measured, mitochondria showing higher affinity to NADH. Above a half of respiratory rate remained unchanged even at very low oxygen concentrations. Fumarate exhibited inhibitory activity on respiration of T. crassiceps mitochondria. Respiration in which NADH was used as substrate was twice as much more sensitive to inhibition by fumarate than respiration stimulated by succinate.     

Susceptibility of IFN-gamma or IL-12 knock-out and SCID mice to infection with two microsporidian species, Encephalitozoon cuniculi and E. intestinalis

Susceptibility of three strains of immunodeficient mice to two related microsporidian species Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 and Encephalitozoon intestinalis (Cali, Kotler et Orenstein, 1993) was compared. While both, severe combined immunodeficient (SCID) and interferon-gamma knock-out (IFN-gamma KO) mice, succumbed to either intraperitoneal (i.p.) or peroral (p.o.) (natural) infection with both parasites, only i.p. infection with E. cuniculi killed interleukin-12 knock-out (IL-12 KO) mice. IFN-gamma KO mice died earlier than SCID mice. Adoptive transfer of naive splenocytes from IFN-gamma KO mice did not protect the SCID mice from a lethal infection with either of the Encephalitozoon species. However, reconstituted mice survived significantly longer (P<0.05), thus indicating the role of IFN-gamma produced by host NK cells in the development of mechanisms of anti-microsporidial protective immunity. Non-lethal outcome of the infection always correlated with the increase in CD8+ T lymphocyte subpopulation. Both E. intestinalis-infected IFN-gamma KO and IL-12 KO mice produced comparable levels of specific antibodies, suggesting that antibodies did not protect IFN-gamma KO mice from lethal infection.