Although microbes have traditionally been used as models for testing ecological theory, research on the organization of these communities has largely been isolated from other areas of community ecology. Early studies ...Although microbes have traditionally been used as models for testing ecological theory, research on the organization of these communities has largely been isolated from other areas of community ecology. Early studies indicated that microbial populations can form dynamic, interacting assemblages. Observations of distributional patterns suggest that certain deterministic forces regulate community structure. It appears that protozoans are tolerant of a wide range of environmental conditions although evidence for this is largely based on gross environmental analyses. Laboratory studies have suggested the importance of negative and positive biotic interactions in determining community membership, but little field evidence for this exists. The importance of transport processes in controlling community composition is being increasingly recognized. All three types of processes likely act to regulate the colonization and successional dynamics of these communities. A simple model is presented to promote the展开更多
AIM To investigate the putative role of protozoan parasites in the development of irritable bowel syndrome(IBS).METHODS The study included 109 IBS consecutive adult patients fulfilling the Rome Ⅲ criteria and 100 hea...AIM To investigate the putative role of protozoan parasites in the development of irritable bowel syndrome(IBS).METHODS The study included 109 IBS consecutive adult patients fulfilling the Rome Ⅲ criteria and 100 healthy control subjects. All study subjects filled a structured questionnaire, which covered demographic information and clinical data. Fresh stool samples were collected from patients and control subjects and processed within less than 2 h of collection. Iodine wet mounts and Trichrome stained smears prepared from fresh stool and sediment concentrate were microscopically examined for parasites. Blastocystis DNA was detected by polymerase chain reaction, and Cryptosporidium antigens were detected by ELISA.RESULTS A total of 109 IBS patients(31 males, 78 females) with a mean age ± SD of 27.25 ± 11.58 years(range: 16-60 years) were enrolled in the study. The main IBS subtype based on the symptoms of these patients was constipation-predominant(88.7% of patients). A hundred healthy subjects(30 males, 70 females) with a mean ± SD age of 25.0 ± 9.13 years(range 18-66 years) were recruited as controls. In the IBS patients, Blastocystis DNA was detected in 25.7%, Cryptosporidium oocysts were observed in 9.2%, and Giardia cysts were observed in 11%. In the control subjects, Blastocystis, Cryptosporidium and Giardia were detected in 9%, 0%, and 1%, respectively. The difference in the presence of Blastocystis(P = 0.0034), Cryptosporidium(P = 0.0003), and Giardia(P = 0.0029) between IBS patients and controls was statistically significant by all methods used in this study.CONCLUSION Prevalence of Blastocystis, Cryptosporidium and Giardia is higher in IBS patients than in controls. These parasites are likely to have a role in the pathogenesis of IBS.展开更多
Vibrio harveyi, known as a pathogenic bacterium caused severe secondary bacterial infections of the large yellow croaker Larimichthys crocea, was identified as an endosymbiont in the marine parasitic ciliate protozoan...Vibrio harveyi, known as a pathogenic bacterium caused severe secondary bacterial infections of the large yellow croaker Larimichthys crocea, was identified as an endosymbiont in the marine parasitic ciliate protozoan Cryptocaryon irritans. Meta 16 S sequencing method was used to identify the bacterial flora in C. irritans, and V.harveyi was isolated via culture-dependent method. Vibrio harveyi was observed in cytoplasm of C. irritans at the stage of tomont both by transmission electron microscopy and by Fluorescence in situ hybridization; no signal,however, was detected in nucleus area. The relationship between V. harveyi and C. irritans and the role of endosymbiotic V. harveyi in C. irritans merit further investigation.展开更多
A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rate...A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rates on artificial substrates(polyurethane foam units) were compared between two field stations(A and B), and their presence were considered with regards to the prevailing water quality conditions at the study sites. Altogether 44 genera of flagellates and ciliates were documented. The common genera of flagellates encountered included Monas, Polytoma, and Chromalina. Among the ciliates, the predominant genera were Tetrahymena, Vorticella, Lagynophyra, and Heloiphyra. These groups exhibited characteristic successional patterns in relation to ambient water quality. At Station A, located close to the sewage outfall, the water quality parameters included poor Secchi disc transparency(0.48m), dissolved oxygen of 1.93 mg/ml, salinity of 18 psu, and temperature 31.3 ℃. Here, the nanoflagellates( spumella ) colonized first, followed by microcilliate( Tetrahymena ) and sessile form( Vorticella ). Station B, located on the seaward side, was characterized by relatively less stressed environmental conditions with transparency 1.85m and dissolved oxygen value of 6 04 mg/ml. Salinity of 27.27 psu, and mean temperature of 30 ℃ were recorded at “B'. At this station, the nanoflagellate Polytoma was first documented to colonize on the substrates, followed by microcilliate( Lagynophrya ) and suctorid( Heliophyra ). These findings support the use of protozoans as indicator species for evaluating the hazards posed by organic pollution to natural estuarine communities.展开更多
Vector-borne protozoan diseases represent a serious public health challenge,especially in the tropics where poverty together with vector-favorable climates are the aggravating factors.Each of the various strategies cu...Vector-borne protozoan diseases represent a serious public health challenge,especially in the tropics where poverty together with vector-favorable climates are the aggravating factors.Each of the various strategies currently employed to face these scourges is seriously inadequate.Despite enormous efforts,vaccines-which represent the ideal weapon against these parasitic diseases—are yet to be sufficiently developed and implemented.Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden.Nowadays,both strategies are also highly challenged by the phenomenon of drug and insecticide resistance,which affects virtually all interventions currently used.The recently growing support from international organizations and governments of some endemic countries is warmly welcome,and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases,especially malaria,leishmaniasis,Human African Trypanosomiasis(HAT),and Chagas disease.展开更多
Soil protozoan is the third largest taxon in soil biota and an important biological regulator for soil organisms and biochemical activities because of its biodiversity predacity and enormous biomass in soil. Different...Soil protozoan is the third largest taxon in soil biota and an important biological regulator for soil organisms and biochemical activities because of its biodiversity predacity and enormous biomass in soil. Different trophic types such as photosynthetic autroph, saprotroph and predacity existed in protozoan. Since predation not only controls the bacteria community but also stimulate nutrient transformation and carbon cycling, the study on protozoan community structure and ecological function is one of the bases for elucidating the soil fertility. The article reviewed the research progresses in protozoan community, trophic types, ecological function and application in soil.展开更多
文摘Although microbes have traditionally been used as models for testing ecological theory, research on the organization of these communities has largely been isolated from other areas of community ecology. Early studies indicated that microbial populations can form dynamic, interacting assemblages. Observations of distributional patterns suggest that certain deterministic forces regulate community structure. It appears that protozoans are tolerant of a wide range of environmental conditions although evidence for this is largely based on gross environmental analyses. Laboratory studies have suggested the importance of negative and positive biotic interactions in determining community membership, but little field evidence for this exists. The importance of transport processes in controlling community composition is being increasingly recognized. All three types of processes likely act to regulate the colonization and successional dynamics of these communities. A simple model is presented to promote the
基金Supported by Deanship of Research,Jordan University of Science and Technology,No.214/2013
文摘AIM To investigate the putative role of protozoan parasites in the development of irritable bowel syndrome(IBS).METHODS The study included 109 IBS consecutive adult patients fulfilling the Rome Ⅲ criteria and 100 healthy control subjects. All study subjects filled a structured questionnaire, which covered demographic information and clinical data. Fresh stool samples were collected from patients and control subjects and processed within less than 2 h of collection. Iodine wet mounts and Trichrome stained smears prepared from fresh stool and sediment concentrate were microscopically examined for parasites. Blastocystis DNA was detected by polymerase chain reaction, and Cryptosporidium antigens were detected by ELISA.RESULTS A total of 109 IBS patients(31 males, 78 females) with a mean age ± SD of 27.25 ± 11.58 years(range: 16-60 years) were enrolled in the study. The main IBS subtype based on the symptoms of these patients was constipation-predominant(88.7% of patients). A hundred healthy subjects(30 males, 70 females) with a mean ± SD age of 25.0 ± 9.13 years(range 18-66 years) were recruited as controls. In the IBS patients, Blastocystis DNA was detected in 25.7%, Cryptosporidium oocysts were observed in 9.2%, and Giardia cysts were observed in 11%. In the control subjects, Blastocystis, Cryptosporidium and Giardia were detected in 9%, 0%, and 1%, respectively. The difference in the presence of Blastocystis(P = 0.0034), Cryptosporidium(P = 0.0003), and Giardia(P = 0.0029) between IBS patients and controls was statistically significant by all methods used in this study.CONCLUSION Prevalence of Blastocystis, Cryptosporidium and Giardia is higher in IBS patients than in controls. These parasites are likely to have a role in the pathogenesis of IBS.
基金The National Natural Science Foundation of China under contract Nos 31372504,41176115 and 41476118
文摘Vibrio harveyi, known as a pathogenic bacterium caused severe secondary bacterial infections of the large yellow croaker Larimichthys crocea, was identified as an endosymbiont in the marine parasitic ciliate protozoan Cryptocaryon irritans. Meta 16 S sequencing method was used to identify the bacterial flora in C. irritans, and V.harveyi was isolated via culture-dependent method. Vibrio harveyi was observed in cytoplasm of C. irritans at the stage of tomont both by transmission electron microscopy and by Fluorescence in situ hybridization; no signal,however, was detected in nucleus area. The relationship between V. harveyi and C. irritans and the role of endosymbiotic V. harveyi in C. irritans merit further investigation.
文摘A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rates on artificial substrates(polyurethane foam units) were compared between two field stations(A and B), and their presence were considered with regards to the prevailing water quality conditions at the study sites. Altogether 44 genera of flagellates and ciliates were documented. The common genera of flagellates encountered included Monas, Polytoma, and Chromalina. Among the ciliates, the predominant genera were Tetrahymena, Vorticella, Lagynophyra, and Heloiphyra. These groups exhibited characteristic successional patterns in relation to ambient water quality. At Station A, located close to the sewage outfall, the water quality parameters included poor Secchi disc transparency(0.48m), dissolved oxygen of 1.93 mg/ml, salinity of 18 psu, and temperature 31.3 ℃. Here, the nanoflagellates( spumella ) colonized first, followed by microcilliate( Tetrahymena ) and sessile form( Vorticella ). Station B, located on the seaward side, was characterized by relatively less stressed environmental conditions with transparency 1.85m and dissolved oxygen value of 6 04 mg/ml. Salinity of 27.27 psu, and mean temperature of 30 ℃ were recorded at “B'. At this station, the nanoflagellate Polytoma was first documented to colonize on the substrates, followed by microcilliate( Lagynophrya ) and suctorid( Heliophyra ). These findings support the use of protozoans as indicator species for evaluating the hazards posed by organic pollution to natural estuarine communities.
基金The present work was supported by a research grant awarded to Dr.Denis Zofou by the International Foundation for Science(IFS),Stockholm,Swedenthe Organization for the Prohibition of Chemical Weapons,The Hague,Netherlands(IFS-OPCW,Grant No F/5122-1).
文摘Vector-borne protozoan diseases represent a serious public health challenge,especially in the tropics where poverty together with vector-favorable climates are the aggravating factors.Each of the various strategies currently employed to face these scourges is seriously inadequate.Despite enormous efforts,vaccines-which represent the ideal weapon against these parasitic diseases—are yet to be sufficiently developed and implemented.Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden.Nowadays,both strategies are also highly challenged by the phenomenon of drug and insecticide resistance,which affects virtually all interventions currently used.The recently growing support from international organizations and governments of some endemic countries is warmly welcome,and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases,especially malaria,leishmaniasis,Human African Trypanosomiasis(HAT),and Chagas disease.
文摘Soil protozoan is the third largest taxon in soil biota and an important biological regulator for soil organisms and biochemical activities because of its biodiversity predacity and enormous biomass in soil. Different trophic types such as photosynthetic autroph, saprotroph and predacity existed in protozoan. Since predation not only controls the bacteria community but also stimulate nutrient transformation and carbon cycling, the study on protozoan community structure and ecological function is one of the bases for elucidating the soil fertility. The article reviewed the research progresses in protozoan community, trophic types, ecological function and application in soil.
