A new species in the genus Cyrtostrombidium (Ciliophora,Oligotrichia, Oligotrichida): its morphology,seasonal cycle and resting stage

Cysts of an oligotrich ciliate were collected from natural sediment samples in Onagawa Bay, northeastern coast of Japan, and examined for their excystment capability. A high excystment ratio was obtained at lower temperatures of 10 or 15 degrees C; no excystment occurred at 20 degrees C. Excysted vegetative cells were observed after protargol staining and were identified as a new species, Cyrtostrombidium boreale n. sp. The seasonal changes in the vegetative population and sedimentation of newly formed cysts were also investigated in situ. Planktonic vegetative cells were abundant during the cold season from February to May, when the water temperature was lower than 10 degrees C. Mass encystment occurred abruptly just after the seasonal peak of the vegetative population in April. These results indicate that C. boreale is a cold-water species and aestivates during the longer, warm period from late spring to fall.     

The parasitemia of cloned Trypanoplasma borreli Laveran and Mesnil, 1901, in laboratory-infected common carp (Cyprinus carpio L.)

The course of parasitemia of cloned Trypanoplasma borreli in laboratory-infected common carp was investigated. In 25-42-g carp kept at 20 C, the prepatent period was 8 days; after a phase of exponential growth, the parasitemia peaked at day 39 postinjection (PI) at a level of about 10(3) T. borreli/microliters blood. This maximum was followed by a chronic phase of about 6 wk with large numbers of T. borreli. At 20 wk PI, T. borreli was absent in infected carp. In 2.2-g carp kept at 20 C, the prepatent period was 4 days only, and the parasitemia peaked at day 23 PI. At 30 C, T. borreli was present in the blood only for 12 wk, and the number of T. borreli did not exceed 162 trypanoplasms/microliters blood. Carp kept at 8 and 15 C showed retarded development of parasitemia. The prepatent period lasted longer and the generation time was increased, but the level of parasitemia was not affected. Carp, inoculated at 8 C and then warmed to 20 C on days 27 and 55 PI, developed a parasitemia of 10(4) flagellates/microliters blood and showed high mortalities. During the prepatent period, T. borreli was found in the muscle tissue of the inoculation area but in no other tissue. In the kidney, T. borreli was found 27 hr PI, whereas in the circulating blood it was manifest at day 3 PI. At the same time it was manifest in the liver and spleen.     

Infectivity of sarcocystis from donkey for horse via sporocysts from dogs

The dog is the final host for sarcosporidia cysts from the oesophagus and diaphragm of donkeys from Sardinia. The prepatent period lasted 9 to 10 days. Sporocysts measured 12.2-13.8 X 9.2-9.9 microns. Infection of a horse with 10(5) donkey/dog sporocysts increased the rectal temperature to more than 40 degrees C on days 10 and 20 after infection. On day 138 p.i. predominantly immature cysts containing metrocytes were found, especially in the oesophagus. Infection on day 117 p.i. with 2 X 10(5) horse/dog sporocysts did not give rise to a temperature increase during the following 21 days. The final host of sarcosporidia cysts from the oesophagus and diaphragm of horses from Sardinia is the dog. The prepatent period lasted 9-10 days. Sporocysts measured 12.2-13.8 X 9.2-9.9 microns. The rise in the rectal temperature of three foals infected with horse/dog sporocysts did not differ from that of the foal infected with donkey/dog sporocysts. In both cases rectal temperature increased to more than 40 degrees C on days 10 and 20 following infection with 10(5) sporocysts. Because of the occurrence of two temperature peaks following infection, two generations of schizogony are postulated. The presence of a sarcosporidia species occurring in the donkey only is doubtful.     

The prepatent period and cercarial production of Schistosoma haematobium in Bulinus truncatus (Egyptian field strains) at different constant temperatures

The developmental time of Schistosoma haematobium in Bulinus truncatus snails (field strains) was determined in the laboratory at different constant temperatures between 18 and 32 degrees C. The basic relationship between the length of the minimum prepatent period (y, in days) and the temperature (x, in degree C) is given by the hyperbolic formula y = 295/(x-15.3), 15.3 being the theoretical "developmental null point" and 295 the constant time-temperature product. The shortest prepatency was 17-19 days at 30, 31 and 32 degrees C; at 18 degrees C, cercarial development required at least 106-113 days. The maturation time frequently exceeded the possible minimum by several weeks. No schistosome matured in our experiments at 17 degrees or 33 degrees C. The cercarial release per snail at weekly exposures showed a maximum at 25 degrees C with a geometric mean of 109 cercariae (95% confidence limits 79-149), decreasing to 8 (2-30) at 18 degrees C and 62 (38-100) at 32 degrees C. The absolute maximum of cercariae shed by one snail during 5 h "stimulation" was 2,150 in a 25 degrees C batch, 48 at 18 degrees C and 529 at 32 degrees C. The epidemiological application, the prognosis of the transmission period and the estimation of the transmission potential in relation to climatic conditions are discussed.     

Effect of phosphoenolpyruvate on metabolic and morphological recovery of red cells after prolonged liquid storage and subsequent freezing in glycerol medium.

The present study was designed to determine the effects of (i) phosphoenolpyruvate (PEP) treatment of red blood cells (RBCs) previously cold stored for a prolonged period in a liquid medium and (ii) the freezing of these treated cells in glycerol. RBCs stored for 21 days at 4 degrees C were incubated for 30 min at 37 degrees C with rejuvenant solution containing 50 mM PEP, 60 mM mannitol, 30 mM sodium chloride, 25 mM glucose, and 1 mM adenine, pH 6.0, and then frozen at -80 degrees C for 4 weeks. Red cell recovery as frozen and thawed red cells (FTRCs) after deglycerolization was increased to 80 +/- 4% compared to 43 +/- 9% in units without rejuvenation; the percentage of PEP-treated FTRCs was similar to the percentage of FTRCs recovered from fresh RBCs within 5 days after donation. Incubation of RBCs with PEP solution restored ATP and 2,3-DPG to levels seen in fresh RBCs, and also facilitated transformation of crenated RBCs to discocytes. These results indicate that maximum recovery of viable RBCs can be attained when FTRCs are processed from cells stored in the frozen state after they had been rejuvenated with PEP even after prolonged liquid storage.     

Eclosion rate, development and survivorship of Aedes albopictus (Skuse)(Diptera: Culicidae) under different water temperatures

In tropical areas, where vector insects populations are particularly numerous, temperature usually range between 25 degrees C and 35 degrees C. Considering the importance of such temperature variation in determining mosquitoes population dynamics, in this work the developmental, eclosion and survival rates of the immature stages of Aedes albopictus (Skuse) were compared under constant 25, 30 and 35 degrees C (using acclimatized chambers) and environmental (25 degrees C to 29 degrees C) temperatures. The hatching rate was considered as total number of larvae recovered after 24h. The development period as well as larval and pupal survival rate were evaluated daily. Eclosion rate was significantly higher under environmental temperature than under the studied constant temperatures, suggesting that temperature variation may be an eclosion-stimulating factor. The mean eclosion time increased with the temperature, ranging from 2.8h (25 degrees C) to 5.2h (35 degrees C). The larval period was greatly variable inside each group, although it did not differ significantly amongst groups (11.0 +/- 4.19 days), with individuals showing longer larval stages in water at 35 degrees C (12.0 +/- 4.95 days) and environmental temperature (13.6 +/- 5.98 days). Oppositely, survival was strongly affected by the higher temperature, where only one individual lived through to adult phase. The results suggest that population of Ae. albopictus from Recife may be adapting to increasing of environmental temperatures and that the limiting temperature to larval development is around 35 degrees C.     

Experimental fascioliasis in the rat-like hamster,Tscherskia triton,and other rodent hosts

Experimental infection with Fasciola hepatica and parthenogenetic Fasciola sp. in laboratory animals have been conducted in rats and rabbits. Inoculation of less than 5 metacercariae into rat-like hamsters, Tscherskia triton, is sufficient to establish Fasciola infections. The prepatent period of F. hepatica and the parthenogenetic Fasciola sp. in T. triton was shorter than that in rats and rabbits, suggesting that T. triton is a suitable experimental model for these flukes. In contrast, F. gigantica infection in T. triton did not yield adult flukes; T. triton, is therefore, considered to be an unsuitable host for F. gigantica. The cotton rat, Sigmodon hispidus, was an unsuitable host for the parthenogenetic Fasciola sp.     

The effect of host age on Rana temporaria-gorgoderina vitelliloba interactions

Mitchell J. B. 1982. The effect of host age on Rana temporaria-Gorgoderina vitelliloba interactions. International Journal for Parasitology12: 601–604. Two age groups of tadpoles, and newly metamorphosed and adult male Rana temporaria were fed the metacercarial cysts of Gorgoderina vitelliloba. In the younger tadpoles metacercariae died in their cysts. In the older tadpoles excystment took place and juvenile flukes invaded the kidneys, killing the hosts within 72 h. In newly metamorphosed frogs, an immunological response resulted in some of the juvenile flukes in the kidneys being attacked by eosinophils which adhered to and dissolved the tegument, presumably killing the flukes. In contrast, some young frogs were harmed by flukes in their kidneys. Migration away from the kidneys to the bladder took place on about the twelfth day after infection. Juvenile flukes in the kidneys of adult frogs 7 and 14 days after infection, evoked an inflammatory reaction involving polymorphs and lymphocytes. These cells did not appear to damage the parasites.     

紫花苜蓿种子对逆境贮藏条件的反应

以陇东紫花苜蓿 (MedicagosativaL .cv .“Longdong”)种子为材料 ,在室温、35℃和 35℃ +10 %的种子含水量 (SMC) 3种贮藏、接种或不接种燕麦镰刀菌 (Fusariumavenaceum (Fr.)Sacc .)的条件下 ,1年贮藏期内对各逆境处理的种子每隔 6 0d进行 1次标准发芽试验 ,2 0℃恒温、第 10d统计种子的发芽率和死亡率 ,试验结束时计测种子幼苗的长度和感病率 ;在大田条件下观测各处理种子的出苗率 ,确定催腐 (CD)与各种贮藏条件下的苜蓿种带真菌种类和检出率 .结果表明 ,随着贮藏温度和种子含水量等逆境贮藏条件胁迫的加剧 ,苜蓿种带真菌检出率逐渐增高 ,从室温、35℃条件下的 10 %上升到CD +35℃ +10 %SMC条件下的 2 9% ;抗病性逐渐减弱 ,35℃ +10 %SMC条件下幼苗的感病率和种子死亡率显著 (P <0 .0 5 )高于室温和 35℃下的感病率和种子死亡率 ;室内种子发芽率和田间出苗率逐渐下降 ,35℃ +10 %SMC条件下的种子的发芽率和田间出苗率显著 (P <0 .0 5 )低于在室温和 35℃下的发芽率和田间出苗率 ;幼苗生长受到抑制 ,35℃ +10 %SMC条件下的苗长和根长显著 (P <0 .0 5 )低于在室温和 35℃下的幼苗长度 .随着贮藏时间的延长 ,种子真菌检出率和田间出苗率下降 ,幼苗感病率增加 .与未接种的对照相比 ,接种燕麦镰刀菌的种子     

Differences in thermotolerance induced by heat or sodium arsenite: cell killing and inhibition of protein synthesis

Chinese hamster ovary (CHO) cells became thermotolerant after treatment with either heat for 10 min at 45.5 degrees C or incubation in 100 microM sodium arsenite for 1 h at 37 degrees C. Thermotolerance was tested using heat treatment at 45 degrees C or 43 degrees C administered 6-12 h after the inducing agent. At 45 degrees C thermotolerance ratios at 10(-2) isosurvival levels were 4.2 and 3.8 for heat and sodium arsenite, respectively. Recovery from heat damage as measured by resumption of protein synthesis was more rapid in heat-induced thermotolerant cells than in either sodium arsenite-induced thermotolerant cells or nonthermotolerant cells. Differences in inhibition of protein synthesis between heat-induced thermotolerant cells and sodium arsenite-induced thermotolerant cells were also evident after test heating at 43 degrees C for 5 h. At this temperature heat-induced thermotolerant cells were protected immediately from inhibition of protein synthesis, whereas sodium arsenite-induced thermotolerant cells, while initially suppressed, gradually recovered within 24 h. Furthermore, adding cycloheximide during the thermotolerance development period greatly inhibited sodium arsenite-induced thermotolerance (SF less than 10(-6] but not heat-induced thermotolerance (SF = 1.7 X 10(-1] when tested with 43 degrees C for 5 h. Our results suggest that both the development of thermotolerance and the thermotolerant state for the two agents, while similar in terms of survival, differed significantly for several parameters associated with protein synthesis.     

Life cycle of Trichostrongylus retortaeformis in its natural host,the rabbit (Oryctolagus cuniculus)

The chronology of the life cycle of Trichostrongylus retortaeformis (Zeder, 1800) (Nematoda, Trichostrongyloidea) is studied in its natural host Oryctolagus cuniculus. The free living period lasted 5 days at 24 degrees C. Worm-free rabbits were each infected per os with T. retortaeformis larvae. Rabbits were killed at 12 h post-infection (p.i.) and every day from one day to 13 days p.i. By 12 h p.i., all the larvae were exsheathed and in the small intestine. The third moult occurred between 3 and 5 days p.i. and the last moult between 4 and 7 days p.i. The prepatent period lasted 12 to 13 days. The patent period lasted five and a half months. The four known life cycles of species of Trichostrongylus in ruminants were compared with that of T. retortaeformis. No significant difference was found except in the duration of the prepatent period. These similarities in the life cycles confirm the previously formulated hypotheses on the relationship between the parasites of the two host groups (Durette-Desset, 1985).     

Chronological observation of intestinal lesions of rats experimentally infected with Echinostoma hortense

Intestinal histopathological changes due to infection with Echinostoma hortense (Trematoda) were studied in rats after experimental infection with the metacercariae. The metacercariae were obtained from the tadpoles of Rana nigromaculata, a second intermediate host infected in the laboratory. Total 18 albino rats (Sprague-Dawley) were given 200 matacercariae each and sacrificed on the day 1, 3, 7, 11, 22 or 44 post-infection (PI). Segments of the small intestine at 1, 3, 5, 8 and 30 cm posterior to the pylorus (PTP) were resected and studied histopathologically. 1. The flukes were seen to have intruded into the intervillous space in the upper small intestine at early stages (1-3 days PI), however, they were located mainly in the intestinal lumen at later stages (7-44 days PI). The flukes were sucking and destroying the epithelial layers of villi with their oral and ventral suckers. 2. Histopathological changes of the intestine were recognizable in as early as 1-3 days after infection, and the changes became severer as the infection progressed. 3. The intestinal mucosa was histopathologically characterized by villous atrophy and crypt hyperplasia throughout the infection period. Major villous changes were blunting, fusion, severe destruction and loss of epithelial layers of villi. Villous/crypt (V/C) height ratio was remarkably reduced from 3:1 in controls to 1:1 in severely infected animals. In the stroma of villi, inflammatory cell infiltrations, vascular congestion, edema, and/or fibrosis were recognized. The goblet cells were increased in number after 11 days PI.(ABSTRACT TRUNCATED AT 250 WORDS)     

Haemoproteus columbae: course of infection, relapse and immunity to reinfection in the pigeon.

Studies were performed on the course of infection, relapse, and immunity to reinfection in 11 young pigeons infected with the avian malaria parasite Haemoproteus columbae Kruse. The prepatent period in our experiments varied between 22 and 37 days. The intensity and length of the initial infection period showed wide variations. During this period an initial periodicity of gametocyte production of about 12 days with peaks at about 6-8 and 18-20 days after patency was observed. The various modes of infection (fly bite, intramuscular, intravenous, or intraperitoneal inoculation of sporozoites) did not influence the intensity of the initial infection. No pathogenicity due to heavy infection with the parasite was observed. There was no periodicity of relapse occurrence, nor any correlation between the frequency of relapse and the intensity of the initial infection, and the phenomenon was not influenced by seasonal changes. Pigeons (Columba livia) that had recovered from previous infections were susceptible to reinfection, whereas pigeons with chronic infection acquired immunity (premunition).     

Biology and pathogenicity of Eimeria neodebliecki Vetterling, 1965 in experimentally infected pigs

The endogenous development and pathogenicity of Eimeria neodebliecki Vetterling, 1965 are described in weaned pigs inoculated with 250 000 oocysts. The endogenous stages developed within the apical cytoplasm of the enterocytes of the middle and posterior jejunum. The asexual development comprised two generations of meronts. Immature and mature meronts were found in groups up to five per host cell. The first fully developed macrogametes and mature microgamonts were seen at 9 days post-infection (DPI). The prepatent period was 10 days, and the patent period lasted 6–8 days. Sporulation of oocysts was completed within 12 days at 25°C, and 16 days at 20°C. E. neodebliecki infection produced clinical signs of coccidiosis in weaned pigs which developed frothy or mucoid diarrhea from 9 to 12 DPI. Pathological changes were situated in the second half of the small intestine, with the predilection for the posterior jejunum. At 9 and 10 DPI, macroscopically, ranged from catarrhal to focal, pseudomembranous inflammatory lesions. Histopathological and SEM examinations revealed moderate villous atrophy with focal epithelial erosions and fibrinonecrotic material at the villous tips. E. neodebliecki is pathogenic for pigs and can be associated with clinical manifestation of diarrhea, stunted growth and poor condition in pigs.     

Fasciola hepatica: Simple,large-scale, in vitro excystment of metacercariae and subsequent isolation of juvenile liver flukes

A simple method has been developed for the in vitro excystment of metacercariae of Fasciola hepatica, and for the isolation of large numbers of juvenile liver flukes free from intact metacercariae and from cyst-wall material. In this method, the outer cyst wall was removed by gently grinding the metacercariae between small glass plates. The metacercariae were activated by incubation for 1 hr under $\text{60\%}\text{CO}{}_2\text{40\%}\text{N}{}_2$ and excysted by the addition of 10% sterilized sheep bile or an equivalent amount of taurocholic acid. Excystment was accomplished in an experimental apparatus allowing the newly excysted juveniles to escape from the bile-containing excystment medium into a medium with low bile content. The yield of isolated liver flukes was 60–80%; their protein content was about 125 ng. Both bile and taurocholic acid, though necessary for excystment, were detrimental to the survival of the juvenile liver flukes. The presence of bile in the host intestine may be a stimulus for juveniles to leave the gut and enter the abdominal cavity.     

Development of the large American liver fluke, Fascioloides magna, in white-tailed deer, cattle, and sheep.

The comparative development of Fascioloides magna in white-tailed deer, cattle and sheep has been studied. Flukes were recovered from 72% of 32 deer administered 40 to 500 metacercariae, from 82% of 11 cattle administered 10 to 500 metacercariae, and from 53% of 15 sheep administered 8 to 200 metacercariae. The percentage recovery of the flukes administered as metacercariae was 4.1% of 6,130 in deer, 5.7% of 2,510 in cattle, and 4.7% of 1,213 in sheep. Flukes were recovered only from livers of infected deer, while in cattle, 1 fluke was also found in the lungs of each of 2 animals. In sheep, all but 10 flukes were recovered from the livers; 6 were found in the lungs and 4 in the abdominal cavities. The black iron porphyrin pigment associated with F. magna infection was found to be most widespread in cattle and sheep, but was also a pathognomonic feature in deer. Growth of the fluke was similar in all 3 host species tested, but eggs were passed only from deer, the normal definitive host. In cattle, the eggs were retained in the liver, and F. magna was lethal to sheep before its own maturity was attained. In cattle and deer, flukes matured approximately 7 months after exposure, but immature migrating flukes were found 12 months after infection and apparently can remain in this retarded state for an undetermined period of time.     

Recovery rate, growth and development of Heterophyopsis continua in experimental chicks

The growth and developmental pattern of H. continua was observed after experimental infection of their metacercariae to chicks. The recovery rate of worms from the chicks at 1 to 28 days post-infection (PI) was 12.8% in average. The rate remained fairly high for early 4 days of infection but decreased thereafter rapidly till 28 days PI. Most of the flukes, 91.9%, were recovered from the ileum of the chicks. In metacercariae, genital organs such as the ovary, testes, seminal vesicle, seminal receptacle and genital sucker were recognizable. At one day PI Mehlis' gland appeared, and at 2 days follicular vitellaria were observed. At 3 days PI, eggs were formed in the uterine tubule and increased in number as the worm grew old. The worms reached 2,990 microns in length and 525 microns in width at 28 days PI. Genital organs developed rapidly in early stages of infection but slowly thereafter to 28 days PI, whereas non-genital organs developed steadily through the infection period. It was proved by this experiment that chicks should be a moderately suitable final host of H. continua.     

Growth, development and allometry of Philophthalmus nocturnus in the eyes of domestic chicks.

Fifty day-old chicks were each infected with 10 excysted metacercariae of Philophthalmus nocturnus Looss, 1907 around each orbit and growth, development and allometry were studied. The growth rate showed two phases over a period of 35 days, a limited lag phase lasting two days post-infection in which flukes did not exceed 440 microns in length, and a rapid phase during which growth was rapid and flukes reached a size of 3.008-3.504 mm on day 35. Five developmental stages were noticed during the course of development of the metacercaria to the egg-producing adult stage. Eggs appeared in the uterus on day 14 and oculate miracidia on day 25. The hindbody, testes and ovary showed positive allometric growth, the pharnyx less so, whereas negative allometric growth was shown by the forebody. Body width, oral sucker and ventral sucker were close to isometry, growing at the same rate as the body length.     

The effects of low temperature on fertilized rabbit ova in vitro,and the normal development of ova kept at low temperature for several days

Fertilized rabbit ova at the 2-blastomere stage kept in rabbit serum were stored at low temperatures for various lengths of time. They were then cultured at 38 degrees C. for about 24 hours to determine their viability. A number of the viable ova were finally transplanted into recipient does. It was found that rapid cooling of ova to 5 degrees or to 0 degrees C. was more harmful to the subsequent viability of ova than slow cooling. Rapid cooling was not more lethal to the ova than slow cooling, but did prevent their future normal cleavage. There was no difference between those ova cooled rapidly or slowly to 10 degrees C. It was concluded that temperature shock has an adverse effect on ova, especially at the lower temperatures, though temperature shock can be remedied by acclimatization (slow cooling). Thus, the physiological significance of temperature shock would seem to be broadened. The optimal temperature for the storage of ova was investigated. It was found that 10 degrees C. was the best temperature; at this temperature viable ova were obtained after storage for 144 to 168 hours. At 0 degrees , 5 degrees , or 15 degrees C. the ova were viable for 96 to 120 hours, while at 22-24 degrees C., only for 24 to 48 hours. The percentage of dead ova was low at a favorable temperature, increasing only at the end of the storage period. At an unfavorable temperature, however, the rate of death increased steadily from beginning to end of storage. The percentage of abnormally cleaved ova (arrested cleavage and fragmentation) remained at a low level at first at a favorable temperature, but then increased just before or during death of the ova. A critical time for the viability, the abnormal cleavage, and the death of ova was characteristic of each temperature. About 24 to 28 per cent of the viable ova remaining after being stored at 0-15 degrees C. for 2 to 4 days and cultured at 38 degrees C. for 24 hours were capable of development into normal young. The compatibility of serum and ova, the absence of a correlation between the viability of the ova and the source of the fertilizing spermatozoa, and the fertilization of superovulated ova (i.e., the percentage of fertile does in follicular phase and in luteal phase, the percentage of unfertilized ova and of fertilized ova at different stages, the percentage of does that had produced a normal number of ova or had produced a large number of ova, etc.), are reported. The possibility of a more efficient utilization of the germ cells of valuable animals by means of the present techniques, and the possibility of a new approach to the experimental investigation of mammalian genetics and development, have been mentioned.     

Host-parasite relationship of Bulinus forskalii (Ehrenberg) and Schistosoma intercalatum Fisher 1934, from Cameroun.

The susceptibility of 13 different B. forskalii strains from Zaire, Cameroun, Gabon, Senegal, Rhodesia and Tanzania and B. reticulatus wrighti Aden has been tested to infection with Schistosoma intercalatum from Cameroun. The most common prepatent period was 23-28 days. B. forskalii from Zaire, Cameroun and Gabon were excellent intermediate hosts with infection rates varying from 59-0 to 97-4% and with very low death rates, 0-28-4%. The strains from Senegal and Rhodesia had infection rates from 50-0 to 58-4%. B forskalii from Tanzania was refractory. 53-0% of the exposed B. reticulatus wrighti was infected. The total cercariae production per snail varied from 1000-11000. The duration of the infection varied from 8 to 174 days.