Table of Content

31 August 1991, Volume 9 Issue 3

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EXPERIMENTAL STUDIES ON THE CONCURRENT INFECTIONS WITH ENTAMOEBA HISTOLYTICA AND SCHISTOSOMA JAPONICUM

1991, 9(3):  161-165. 

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The mongolian gerbil (Merious unguiculatus) was used as an experimental animal mo-del for studying the concurrent infections and pathogenicities with Entamoeba histolytica (E. h.) and Schistosoma japonicum (S. j.) by the cutaneous infection with 20 fresh cercariae of S. j, and the intracaecal inoculation of 5×105/0.5ml amebic suspension. Light and electron microscopy were used to observe the pathological changes of the caecal wall in the concurrent infections. The results showed that S. j. infection could promote the development of caecal amoebiasis, and stimulate symbiotic E. h. infection to develop invasive caecal amoebiasis. The pathological characteristics of the concurrent two infections not only exhibi- ted the characteristics of the single E. h. or S. j. infection, but also showed its own spe-cdality. Immunological effect of the host was apparently involved in the pathogenic process. In addition, the trophozoites of E. h. were usually observed to adhere closely to the egg shell of S. j. at the site of tissus necrosis. From the adherence phenomenon observed in our studies, there might exist an affinity mechanism between the E. h. trophozoite and S. j. ovum (Figs. 1-14).

STUDIES ON THE STRAIN DIFFERENCES OF SCHISTOSOMAJAPONICUM IN THE MAINLAND OF CHINA IV. FUZZY CLUSTER ANALYSIS ON SOME BIOLOGICAL CHARACTERS OF DIFFERENT ISOLATES OF SCHISTOSOMA JAPONICVM

1991, 9(3):  166-168. 

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In this paper, a computerized numerical systensatics was used to analyse the 5 different isolates of Schistosoma japonicum in the mainland of China by means of fuzzy clustering method with 32 quantitative data of each isolate about the morphological and biological cha-racters.A dendrogram of the 5 isolates of S. japonicum was constructed on the basis of simi-larity coefficients as S'hown in Figure 1. The phyJogenetic rektionships revealed by the present study show that the two isolates of Anhui and Hubei get together firstly in one group, then the isolates of both Yunnan and Guangxi gather in another group, while the Sichuan isolate is closely related to the group of Anhui-Hubei isoktes, not to the Yunnan onest although both Sichuan and Yunnan isolates were in the southwest China.

PRELIMINARY STUDIES ON THE DIAGNOSIS OF PLASMODIVM FALCIPARVM MALARIA BY MONOCLONAL ANTIBODY SANDWICH DOT-IMMUNOGOLD SILVER STAINING ASSAY

1991, 9(3):  169-172. 

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In this report, the blood samples from 30 falciparum malaria patients with parasftemia 0.015-0.58% and the blood samples from 30 healthy persons were examined by monoclonal antibody (McAb) sandwich dot-immunogold silver staining assay (Dot-IGSSA). When the McAb 11G5, 13A2 and 13A1 were used for sandwith Dot-IGSSA with McAb 14D9 labeled with colloidal gold respectively, the 0.0001% of parasitemia could be detected and the McAb 11G5, 13A1 and 14D9 labeled with colloidal gold could also be used to detect the an-tigens of asexual blood stages of Yunnan and Anhui isolates of Plasmodium falciparum cultured in vitro. These McAbs did not cross-react with the antigens of Plos .Mum know-lesi and Plasmodium berghei, however, the McAbs 13A1 and 14D9 weakly cross-reacted with the antigens of Plasmodium cynomolgi and the antigens in the infected blood samples from patients with vivax malaria (Fig. 1).

STUDY ON STRUCTURE-ACTIVITY RELATIONSHIPS OF HEMOLYTIC TOX1CITY OF PRIMAQUINE DERIVATIVES

1991, 9(3):  173-177. 

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Primaquine (PQ) and it's 13 derivatives were tested in an in vitro assay system incor-; porated with liver-microsomal metabolism for their hemolytic toxicity, and 6 putative meta-; bolites of PQ were also assayed in the same system without microsomal metabolism. The results showed that in the 13 derivatives, the hemolytic toxicity of 4-methyl PQ derivatives was lower than that of PQ while 5-trifluoroacetyl PQ derivatives exhibited similar hemolytic potential to PQ. Various modification of the 8-amino side chain of PQ has no significant effect on the hemolytic toxicity of PQ. In the 6 putative metabolites of PQ, 5-OH PQ and 5,6-OH PQ were the most potent hemolytic toxidants which could produce similar level of methemoglobin formation at concentrations several orders of magnitude less than that of PQ, while the hemolytic toxicity of 6-OH PQ, AQD and AQL was also higher than that of PQ itself. MAQ was the only one which exhibited no hemolytic toxicity.

STUDIES ON THE DETERMINATION OF THE CIRCULATING ANTIGEN IN EXPERIMENTAL TOXOPLASMOSIS

1991, 9(3):  178-181. 

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This paper reports on the regular pattern of growth and decline of the circulating antigen (CA) determined by I-ELISA in experimentally infected rabbits. Toxoplasma antigen was demonstratable in the circulation in 64.7% rabbits 1 day after tachyzoite inoculation and the level of the CA in sera from infected rabbits showed an increase on d4 and reached its peak level on d10-13 after inoculation but declined soon thereafter. CA was not detectable on days 60 to 90 after inoculation, The results suggest that determining CA is a useful means for diagnosing active toxoplasmosis and that I-ELISA might be a promising approach to detect CA in toxoplasmosis.

THE KINETICS OF CELL-MEDIATED CYTOTOXICITY TO SCHISTOSOMULA OF SCHISTOSOMA JAPONICVM WITH SERA FROM INFECTED MICE AT DIFFERENT DURATION

1991, 9(3):  182-185. 

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The tests of antibody-dependent cell-mediated cytotoxicity (ADCC)were performed to observe the kinetics of in vitro killing of Schistosoma japonicum schistosomula mediated by eosinophils, macrophages or neutrophils with infected mouse sera of different duration. The results showed that when complement was not involved, the killing rates of schistosomula mediated by eosinophils or macrophages began to increase significantly at 4 wk post-infection, reached a plateau in 5-7wk and 6-8wk respectively, and then declined to the levels of that at 4wk till llwk. In case of neutrophils, there was no significant cytotoxicity detected. When complement was involved, all the three effector cells could mediate cytotoxicity to schistosomula, with the killing rates higher than ihose without complement at the correspondent time intervals. These indicate that ADCC appears to be an important ingredient in the acquired resistance to S. japonicum, and demonstrate that eosinophil- and macrophage-mediated cytotoxicity to schistosomula is complement-independent, whereas neutrophil-mediated cytotoxicity to schistosomula is complement-dependent. This method may be of some value for chosing optimal time for vaccination and estimating the effectiveness of a candidate vaccine.

EFFECT OF POLY I:C ON THE SPOROZOITE INVASION AND THE DEVELOPMENT OF EXOERYTHROCYTIC FORMS OF PLASMODIUM YOELII YOELII IN RATS

1991, 9(3):  186-189. 

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When Wistar rats were given intravenously with Poly I:C 5mg/kg 18h before sporo-zoite inoculation, the density of exoerythrocytic forms (EEF) in the rat liver 42h after inoculation was markedly decreased, the sporozoite viability being only 5-12% of that of the controls. However, the size and maturation rate of EEF were all normal. When Poly I:C was given 2h after sporozoite inoculation, the sporozoite viability and the size and the maturation rate of EEF were similar to those of the controls. When the sporozoites were inocubated with rat serum containing interferon for 40 min before inoculation, no detrimental effect on the sporozoite invasion and the development of EEF could be found. These findings suggested that the target of antimalarial action of interferon might not be the EEF itself. It is possible that interferon could minimize the sporozoite number by enhancing the phagocytosis and the biocidal activity of macrophages, especially the Kupffer cells.

EXPERIMENTAL STUDY OF SCHISTOSOME IMMUNE RNAON TRANSFER OF CELLULAR AND HUMORALIMMUNITY TO NORMAL MICE

1991, 9(3):  190-192. 

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The present paper reported the extraction of immune RNA (iRNA) from spleen cells of Schistosoma japonicum infected rabbits and the activity of this schistosome iRNA (SiRNA) on transfer of cellular immunity and humoral immunity using macrophage migra-tory inhibition test (MMIT) and Dot-ELISA. The results indicated that specific cellular im-munity could be transferred to normal mice by SiRNA either via in vivo or in vitro sensi-tization. Intraperitoneal inoculation of SiRNA to normal mice may result in production of specific antibodies.

STUDY ON ISOENZYMES OF PARAGONIMVSILOKTSUENENSIS AND PARAGONIMUSWESTERMANI BY ISOELECTRIC FOCUSING

1991, 9(3):  193-197. 

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The isoenzyme patterns of Paragonimus iloktsuenensis and P. westermani were studied by isoelectric focusing on polyacrylamide gels for PGM, MDH, HK, ME, PO and ACP. Interspecific differences were apparent as shown by the isoenzyme profiles of these enzymes examined. MDH was polymorphic with 2 recognizable phenotypes, designated common type and variant type respectively, in P. L and with 3 phenotypes, designated MDH1 ,MDH2 and MDH1-2 respectively, in P. w. The result showed that the two species could be distinguished one from another by such species-specific band patterns of isoenzymes. This suggests that P. w. and P. i. have undergone geneticaly divergent development and P. i. can be regarded as a valid species different from P. w. In the light of MDH polymorphism, some implications of isoenzyme analysis on taxonomy of the genus Paragonimus were discussed (Figs. 1-6).

OBSERVATION ON THE CONTRACTION PROCESS OF OVARIOLES OF ANOPHELES SINENSIS AND ANOPHELES ANTHROPOPHAGVS AFTER OVIPOSITION

1991, 9(3):  198-201. 

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In order to know the process of ovariole contraction after oviposition in Anopheles sinensis and An. Anthropophagus, and to determine the relationship between the ovariole contraction and the physiological age, the observation was conducted in 1988.The laboratory-reared female mosquitoes after 3-5 days of eclosion were fed with mouse blood and were kept in separate finger tubes for oviposition. After oviposition, the mosquitoes were dissected at different time. 30 ovarioles for each mosquito were examined and recorded by Detinova' s method.A total number of 75 An. sinensis with 2 262 ovarioles and 87 An. anthropophagus with 2 591 ovarioles were examined after first oviposition. The duration for ovariole conj traction in the phase of A,B,C,D,E was 1, 3-6, 9-14, 15-18 and 21h respectively. A total number of 40 An. sinensis with 1 337 ovarioles and 34 An. anthropophagus with 1 099 ovarioles were examined after third ovipositions. The duration for ovariole contraction in the phase of A,B,C,D,E was 1, 3-9, 12-15, 18 end 21h respectively. E phase can be found in 21-24h after oviposition. There were 29.3% and 38.0% ovarioles in C and D phase for first oviposition while 48.4% and 46.0% ovarioles in C and D phase for third oviposition. It was found that the contraction occurred first in breadth and then in length. After 9-15h of oviposition, most ovarioles were in the phase of breadth contraction, in which the remnant follicular epithelium of ovarioles aggregated to form several dilatations, which. might result in making erroneous judgement on the physiological age of mosquitoes. It is su?ggested that for determining the physiological age of An. sinensis and An. anthropophagus, the appropriate time for mosquito dissection in field survey is 20h after mosquito collection (Figs. 1-6).

STUDY ON POLYORGANOTROPISM AND HOST TRANSFER OF PAGVMOGONIMVS SKRJABINl IN RAT

1991, 9(3):  202-205. 

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40 days after oral infection of rat with metacercariae of Pagumogonimus skrjabini, a few worms matured sexually in the abdominal cavity or worm-cysts formed in the lungs, while juveniles were detected in the muscles.60-90 days after infection, worm-cysts can not only be detected in the lungs, but also in the liver, mediastinum and abdominal wall, with matured or prematured worms and eggs. It is suggested that P. skrjabini could mature in rat and showed a phenomenon of polyor-ganotropism.By means of host-transfer with small juveniles, a part of them migrated to the lungs and matured, but the worms detected in muscles were still stunted (Figs. 1-4) .

ULTRASTRUCTURAL OBSERVATION ON THE OOCYST DEVELOPMEN T AND SPOROZOITE FORMATION OF PLASMODIVM VIVAX

1991, 9(3):  206-208. 

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The oocyst development of Plasmodium vivax was heralded by the appearance of cyto-plasmic vacuoles and membraneous clefts. These clefts broke up oocyst cytoplasm into many sporoblasts. The onset of transformation from oocyst to sporozoite was heralded by forming pellicular complex, at some point of pelliculum of sporoblast dense inner membrane and subpellicular microtubules formed beneath the plasmalemma. The pellicular complex bulged out to form sporozoite buds appearing as small domes. Following enlargement of sporozoite buds the apical ends of the buds became conical in longitudinal sections with the newly formed apical rings at their truncated apices and then, newly formed dense inner membranes and subpellicular microtubules gradually extended backwards and finally enclosed the sporozoi-tes. Beneath the inner membrane there were a total of 10-12 subpellicular microtubules arranged irregularly as 5+6, 6 + 5, 6 + 6, 7 + 4, 8+3, 10 + 1 and 11 + 1.During the formation of sporozoite, intranuclear spindle appeared in the nucleus, suggest ting that the second meiosis in the life cycle of Plasmodium vivax occurred in developing sporozoites (Figs. 1-16).

STUDIES ON ESTERASE ISOENZYME OF THREE SPECIES OF FLEA

1991, 9(3):  209-212. 

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The patterns of esterase (Est) isoenzyme of 3 flea species were studied by vertical slab polyacrylamide gel e.ectrphoresis (PAGE). The samples prepared from the third larval ins-tar, female and male (the unsucking and sucked one) were run in the same gel slab. The result was as follows: Xenopsylla cheopis showed 14 bands, with 5-6 major bands, Cte-nocephalides felis felis showed 9 bands with 4-5 major bands and Nosopsyllus laeviceps kuzenkovi showed 9 bands with 4-5 major bands. These three species have their common bands as well as respective specific bands. The difference in Est isoenzymogram among families was greater than among genera, displaying a species-specific feature (Figs. 1-4).

SCANNING ELECTRON MICROSCOPIC OBSERVATIONS ON CLON ORCHIS SINENSIS CERCARIAE

1991, 9(3):  213-215. 

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The surface structure of Clonorchis sinensis cercariae was observed under scanning electron microscope.The cercaria was of the parapleuro-lophocercous type. The measurements of the cercariae were as follows: body 137-240 × 62-90μm, tail 320-470 × 21-34μm, oral sucker 27-46 × 23-33μm. The ventral sucker was incompletely developed and much smaller than the oral one. The whole body surface was covered with backward pointing spines. Four horizontal rows of oral spines were found around the mouth opening of the oral sucker. These spines diminished in size with the distance of the rows from the opening and their numbers were 12,18, 19 and 18 respectively. Transverse and longitudinal plicae formed from tegument were found on the surface of the tail, being in connection with dorsal and ventral fins along posterior half of the tail. Many sensory structures or papillae were observed on the body. They were of three different types: 1) papillae with long or short cilia distributed widely on the body surface and around the mouth opening, the number of papillae with cilia on the body surface being greater than that described by Komiya et al(1940); 2) a few sensory fossa on the tail, measuring 1.0×0.6μm; 3) a few ring-type papillae with knob on the body surface with pore of 0.5μm in diameter (FigS, 1-8).

EVALUATION OF MOLLUSCICIDAL EFFECT OF NICOTINANILIDE AGAINST ONCOMELANIA SNAILS

1991, 9(3):  216-218. 

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Both nicotinanilide hydrochloride and nicotinanilide sulfate are water-soluble, their LC50 and LC90 against Oncomelania snails being around 0. 3mg/L and 0. 5mg/L, respectivly, during 24 hour exposoure at 25℃ followed by a 7-day recovery period. The laboratory tests and field trials showed that over 90% of snails were killed within 3 days exposure at 1-2mg/L, and that 18.4%-100% snails on moist soil were killed at over 20℃, exposed to spraying dosage of 1-2g/m2 for 1-3 days. The chemical is highly effective against snails eggs at early stage (cell stage). The LC50 of nicotinanilide to Aristichthys nobilis and Pseu-dorasbora parva is about 200mg/L. The acute oral LD50 in mice is about 2g/kg. Plants tolerate the chemical at 1-2g/m2, but some leaves wilted at ≥5g/m2, dicotyledon in particular. Dermatitis has been reported in individuals frequently exposing to nicotinanilide wettable powder during massive spraying.

BREEDING GRASS CARP AGAINST MOSQUITOES IN RICE FIELD

1991, 9(3):  219-222. 

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In this experimental study, grass carp were bred in rice field (1.9 fish/m2) to control mosquito larvae. 78 days after treatment, the larvae population of An. sinensis and Cu. tritaeniorhynchus dropped down by 87.4% and 80% respectively. Newly hatched 1-2 instar larvae accounted for 73.3% of the larvae remained in rice field after treatment. Eighty-nine samples of fish feces taken from rice field and 10 fishes were examined for breathing sy-phons of mosquito larvae. Breathing syphons were found in 22 fecal samples (24.7% posi-live) and 3 fishes (30% positive). The average number of mosquito larvae devoured by one fish was 861.5 in 24 hours in tap water and 661 in 24 hours in water containing grass and aquatic plants. The simulated field test showed that the average number of mos-quito larvae devoured by fish was 362 larvae in 24 hours. The field trial indicated that the grass carp could not only cut down the mosquito larvae population but also benefit the peasants by increasing the production of both fish and rice.

DIFFERENTIATION OF THE SEX OF TRICHINELLA LARVAE COLLECTED IN CHANGCHUN

1991, 9(3):  223-225. 

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The length of the rectum in male Trichinella spiralis larvae is about twice that in female larvae, being 54.39(50.4-63.0) Mm in males and 28.05(18.9-31.35) Mm in females. The gonad rudiment of the female larvae has already differentiated obviously into semin-ral receptacle rudiment and uterus rudiment, while that of the male larvae remains undiffe-wntiated. The seminal receptacle rudiment is a granular, small mass and dark brown in color, while the uterus rudiment is composed of a column of several cells, and the total length of these two rudiments is 62.18 (50.4-75.6)Mm. Verifications through experimental infections proved that the length of rectum and the degree of differentiation of gonad rudiment might be used as indices to identify the sex of larvae.It was found that the sexual ratio of T. spiralis collected in Changchun was 1.82:1 (1.17-2.59:1).