The Preliminary Report on Rumen Protozoa Grazing Rate on Bacteria with a Fluorescence-Labeled Technique

Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obtain rumen protozoa and bacteria. Two groups were designed as follows： One group was the whole bacteria which were labeled using fluorescence through removing free bacteria from rumen fluid （WFLB）; the other group was the bacteria which were labeled using fluorescence without removing free bacteria from rumen fluid （FLB）. The result indicated that the bacterial predation rates of rumen protozoa was 398.4 cells/（cell h） for the group WFLB, 230.4 cells/（cell h） for the group FLB, when the corresponding values expressed as bacteria-N, they were 2.15 pg N/（cell h） for the group WFLB, and 1.24 pg N/（cell h） for the group FLB, respectively. Extrapolating the assimilation quantity of nitrogen by ciliates on bacteria of Xuhuai goat, there were 103.2 mg N/（d capita） for the group WFLB, and 59.5 mg N/（d capita） for the group FLB, respectively. It was estimated that protein losses due to microbial recycling were 0.645 g pro/（d capita） for the group WFLB and 0.372 g pro/（d capita） for the group FLB, respectively. In addition, the fluorescence-labeled technique would be a potential assay for the determination of bacterial predation rate by rumen protozoa.

Intestinal protozoa and intestinal helminthic infections among schoolchildren in Central Sudan

Objective:To determine the prevalence of intestinal parasitic infections and soil-transmitted helminths(STHs) among primary schoolchildren in El dhayga,Central Sudan.Methods:In this cross-sectional study,three fresh faecal samples were collected from each child,which were examined by direct wet mount,brine flotation,formalin-ether and Kato-Katz techniques.The intensity of each STH infection was expressed as the mean of eggs per gram counts of the three samples.Results:In total,142(90.4%) of 157 children harboured at least one type of intestinal parasite.Ascaris lumbricoides,Hymenolepis nana,Entamoeba histolytica and Giardia lamblia were the most common parasites found,with prevalence rates of 32.5%,30.6%,33.1%and 19.7%,respectively.Out of these 157 children,29(18.5%) harboured more than two intestinal parasitic infections.No cases of Schistosoma mansoni or Enterobius vermicularis were identified. Conclusions:The study demonstrates significant burden of intestinal protozoa and STH infections in this part of Sudan and highlights the need for preventive and intervention measures.

The community structure and microbial linkage of rumen protozoa and methanogens in response to the addition of tea seed saponins in the diet of beef cattle

Background: This study investigated changes in rumen protozoal and methanogenic communities, along with the correlations among microbial taxa and methane(CH_4) production of six Belmont Red Composite beef steers fed tea seed saponins(TSS). Animals were fed in three consecutive feeding periods, a high-grain basal diet for 14 d(BD period) then a period of progressive addition of TSS to the basal diet up to 30 g/d for 20 d(TSS period), followed by the basal diet for 13 d without TSS(BDP post-control period).Results: The study found that TSS supplementation decreased the amount of the protozoal genus Entodinium and increased Polyplastron and Eudiplodinium genera. During BDP period, the protozoa community of steers did not return to the protozoal profiles observed in BD period, with higher proportions of Metadinium and Eudiplodinium and lower Isotricha. The addition of TSS was found to change the structure of methanogen community at the subgenus level by decreasing the abundance of methanogens in the SGMT clade and increasing the abundance of methanogens in the RO clade. The correlation analysis indicated that the abundance of SGMT clade methanogens were positively correlated with Isotricha, and Isotricha genus and SGMT clade methanogens were positively correlated with CH_4 production. While RO clade were positively correlated with the proportion of Metadinium genus, which was negatively correlated with CH_4 emission.Conclusions: These results suggest that different genera of rumen protozoa ciliates appear to be selectively inhibited by TSS, and the change in methanogen community at the subgenus level may be due to the mutualistic relationships between methanogens and rumen ciliates.

The Importance of Three Protozoa in Corn Straw Decomposition and Nutrient Transformation

Three typical soil protozoa of Bodo edax, Colpoda cucullus and Amoeba proteus were inoculated into the soil amended with corn straw. The soils were then incubated at 25℃ for 60 days. It was found that the protozoa, particularly Bodo edax, significantly reduced soil microbial biomass C. However, the decomposition of corn straw was accelerated by the protozoa. Colpoda cucullus significantly enhanced soil available P content, but Amoeba proteus decreased soil available P content. Colpoda cucullus and Bodo edax did not obviously influence NH4+-N and NO3--N contents. In contrast, Amoeba proteus significantly increased both NH4+-N and NO3--N contents.

Molecular detection of vector-borne bacteria and protozoa in healthy hunting dogs from Central Italy

Objective:To determine the pi'evalence of vector-bome bacteria and protozoa in hunting dogs living in Central Italy.Methods:Molecular testing was executed on DNA which was extracted from blood specimens collected from 117 asymptomatic dogs to detect Anaplasma phagocytophilum,Babesia canis(B.canis),Bartonella spp..Coxiella burnetii(C.burnetii).Ehrlichia canis.Hepatozoon canis.and Leislnnania infantum.Results:A total of 48 dogs(41.0%) were infested by Ixodes ricinus and Rhipicephalus sanguineus ticks.Tick-borne infections were observed in 64(54.7%) animals.More in detail.38 dogs(32.5%) screened positive for Hepatozoon canis,24(20.5%) for Bartonella rinsonii subsp.berkhoffii.20(17.1%) for Leishmania infantum,6(5.1%) for C.burnetii,5(4.3%) for B.canis(3 B.canis vogeli and 2 B.canis canis),3(2.5%) for Anaplasma phagocytophilum,and 2(1.7%) for Ehrlichia canis.Mixed infection by 2 agents occurred in 17(14.5%) subjects,by 3 agents in 7(6.0%) dogs,and by 4 agents in 1(0.9%) animal.Conclusions:The results demonstrated that several vector-borne pathogens were circulating in this region and dogs infected by these agents were usually asymptomatic.A relevant finding was the presence of DNA of C.burnetii,a severe zoonotic agent,in the 5.1% of tested dogs,which can be source of infection for their owners not only through tick bites,but also directly with urine,feces and birth products.

SPECIES COMPOSITION AND SEASONAL DENSITY DYNAMICS OF CILIATED PROTOZOA IN BAOAN LAKE WITH PARTICULAR REFERENCE TO THE SUBMERGED MACROPHYTES

From April 1996 to October 1997, regular samplings were carried out monthly at 8 stations in a macrophytic basin of Baoan Lake. From the water samples, 47 genera, 96 species of ciliata were identified. Stations covered with macrophytes had greater number of ciliate species and higher percentage of sessile species. The mixotroph Strombidium viride bearing algal endosymbionts dominated numerically the whole ciliate communities; most of the other dominants were bactivores. Total ciliate density in Lake Baoan was 6170-34310 ind./L. The seasonal density fluctuations of the dominant species populations were also investigated. Maximum abundances were observed in spring and winter during the decay of macrophytes and minimum densities were observed during the summer months of luxuriant macrophytes growth.

PRELIMINARY STUDIES ON THE ROLE OF PROTOZOA IN THE FOOD WEB OF DONGHU LAKE

Plankton from Station I of Donghu Lake, an eutrophic lake, was divided into three groups (2-32 μm, 32-112 μm and >112 μm) by filtering the water sample through 2, 32, 112 μm pores. It was supposed that the 2-32 μm Protozoa (group 1) was fed on by the 32-112 μm Protozoa and small rotifers (group 2) and >112 μm large rotifers, cladocerans and copepods (group 3). The feeding rate of zooplankton in situ was estimated by counting the protozoan individuals and also by the 14 C NaHCO 3 method. The P/B ratio of the small Protozoa (group 1) was 2.9 for 6 h and 1.2 for 24 h. The feeding rate of the 32-112 μm zooplankton on small Protozoa (2-32 μm) was about 2/3 the total feeding rate of zooplankton, and that of >112 μm zooplankton on the 2-32 μm Protozoa was 1/3 of the total feeding rate. The lower the density of feeders, the higher were the feeding rates. The daily production of the 2-32 μm protozoans was 1.559 mg/L, which equaled to 25% of the daily food consumption of other zooplankton. Isotope experiments showed result similar to that from the above direct counting method.

An improved glucose-DAB-nickel immunohistochemistry method and its application on protozoan Stylonychia mytilus

Using a modification of the very sensitive glucose-DAB-nickel(GDN)immunohistochemistry method,FOS(the expression protein of the oncogene c-fos)-,neuropeptide Y(NPY)-,somatostatin(SOM)-,leu-enkephalin(L-Enk),cholecystokinin(CCK)-,neurotensin(NT)-,and tyrosine hydroxylase(TH)-immunoreactivities were firstdemonstrated in the protozoan,Stylonychia mytilus.The GDN method and expression ofFOS,neuropeptides and TH in the Stylonychia mytilus were discussed.

Protozoa of Lough Neagh,Northern Ireland,UK

This paper made the first records of taxa composition of protozoa in Lough Neagh,the largest freshwater lake in British Isles. One hundred and eight species(genus)were identified from the examinations of approximately 150 PFU artificial substrates and various types of natural substrate from May to December, 19g2. Of 108 species or genus,30 core species were found on PFU substrate and 17 on natural ones.The ecological characteristics of protozoa were studied by showing the variations of species richness and individual abundance as a function of season or water temperature.Protozoa on PFU were compared at two sampling stations as well.

A Porous Simulation Experiment of Protozoa Movement with Glass Bead

Protozoa can move due to their flagella, cilia or pseudopodia, and play an important role in the transformation and cycling of matter and energy in ecosystems. In this study, the glass beads with the diameters of 1. 0, 0.5, 0. 25 and 0.1 mm were used to simulate soil pores of 0. 292 - 0. 258, 0.155 - 0.116, 0.056 - 0.040 and 0.028 - 0.020 mm respectively. Three typical soil protozoa of Bodo edax, Colpoda cucullus and Amoeba proteus were examined for the relation of their movement to pores. It was found that the smallest protozoan of Bodo edax could be leached through all the pores. However, no more than 26% of the added protozoan was leached out of the column. The leached protozoa were decreased with the pore sizes and leaching duration. The bigger one of Colpoda cucullus was moved out from the column filled with the glass beads of > 0. 5 mm in diameter. Less than about 15% of the added protozoa were leached out of the column. The biggest one of Amoeba proteus could not leached out from any of the pores. It is evident that most of the protozoa remained in the column due to their occupation of the pores.

RNA-binding proteins related to stress response and differentiation in protozoa

RNA-binding proteins(RBPs) are key regulators of gene expression. There are several distinct families of RBPs and they are involved in the cellular response to environmental changes, cell differentiation and cell death. The RBPs can differentially combine with RNA molecules and form ribonucleoprotein(RNP) complexes, defining the function and fate of RNA molecules in the cell. RBPs display diverse domains that allow them to be categorized into distinct families. They play important roles in the cellular response to physiological stress, in cell differentiation, and, it is believed, in the cellular localization of certain mRNAs. In several protozoa, a physiological stress(nutritional, temperature or pH) triggers differentiation to a distinct developmental stage. Most of the RBPs characterized in protozoa arise from trypanosomatids. In these protozoa gene expression regulation is mostly post-transcriptional, which suggests that some RBPs might display regulatory functions distinct from those described for other eukaryotes. mRNA stability can be altered as a response to stress. Transcripts are sequestered to RNA granules that ultimately modulate their availability to the translation machinery, storage or degradation, depending on the associated proteins. These aggregates of mRNPs containing mRNAs that are not being translated colocalize in cytoplasmic foci, and their numbers and size vary according to cell conditions such as oxidative stress, nutritional status and treatment with drugs that inhibit translation.

Research Progress in NTPase of Toxoplasma gondii and Other Protozoa

Nucleoside triphosphate hydrolase （NTPase） is a multifunctional enzymatic family widely existing in vivo. They can hydrolyze NTP to NMP or dNTP to dNMP to produce energy. In this article, the structure of Toxoplasma gondii NTPase is analyzed. The research progress in NT- Pase of Toxoplasrna gondii, Trypanosoma cruzi, Sarcocystis neurona and Neospora caninum was briefly reviewed.

The Impact of Enterohemorrhagic <i>Escherichia coli</i>(EHEC) on Ciliate Protozoan Populations in Municipal Sewage

Enterohemorrhagic Escherichia coli strains (EHEC) have caused many foodborne outbreaks. Bacterivorous protozoa could remove bacteria from aquatic systems. We analyzed the ciliate protozoan population changes influenced by EHEC co-culture in activated sludge. EHEC and non-EHEC control E. coli cells were added to activated sludge samples in microcosms. The ciliate population changes were monitored by terminal restriction fragment length polymorphism (T-RFLP) analysis. EHEC and non-EHEC fed ciliate protozoan populations were different from each other and the no bacteria added controls based on the additive main effects and multiplicative interaction model (AMMI) analysis. Ciliate species were identified by 18S rDNA clone libraries. The 18S rDNA clones from the original sludge sample were identified as Epistylis wenrichi (70%) and Prorodon teres (30%), while clones from EHEC treated sludge sample were identified as P. teres (52%), Vorticella fusca (41%), Dexitrichides pangi (5%), and Opisthonecta henneguyi (2%). This study could provide helpful information about ciliate protozoan population changes caused by different E. coli strains in wastewater treatment plants, which could be useful for preventing and tracking E. coli outbreaks.

Prevalence of Soil-Transmitted Helminths and Intestinal Protozoa among School Children in Lome, Togo

Background: Significant morbidity in children is associated with infectious diseases especially soil-transmitted helminth (STH) infections which are prevalent in sub-Saharan African countries. The objective of this study is to estimate the prevalence of STH and intestinal protozoa among schoolchildren in Lomé, Togo. Patients and Methods: In November 2013, in each of the five districts of the Lomé-commune region, thirty pupils per level of the third, fourth, fifth and sixth grades of five primary schools were included. Each child submitted a single stool sample that was analyzed by the Kato-Katz method for STH. In addition, stool samples of school children selected in third and sixth grades were examined by direct visualization using saline and Lugol’s stain for intestinal protozoa. Results: A total of 2944 children were enrolled at 25 schools. The overall prevalence of STH at schools was 5.0% (range 1.5% to 8.6%), was higher in boys than girls, and increased with age and grade. Hookworm was the most prevalent species (3.4% of children surveyed). Intestinal protozoa were found in 52.2% (765/1465) of children tested and commensal amoebae represented 22.7% of these protozoa identified. Entamoeba histolytica/dispar/moshkovskii and Giardia intestinalis were identified in 2.3% and 11.5% of children, respectively. Co-infestation was noted in 1.35% of children with intestinal helminths and 12.2% of children with protozoa. Conclusion: Although a high prevalence of intestinal protozoa was found in our study, the majority were non-pathogenic protozoa and the low prevalence of STH among school-age children in Lomé-commune region confirms that mass drug administration (MDA) is not needed. Children should receive additional education on best hygiene practices.

Tolerance of ciliated protozoan Paramecium bursaria (Protozoa, Ciliophora) to ammonia and nitrites

The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in order to determine the lethal concentrations. Linear regression analysis revealed that the 2h-LC50 value for ammonia was 95.94 mg/L and for nitrite 27.35 mg/L using probit scale method (with 95% confidence intervals). There was a linear correlation between the mortality probit scale and logarithmic concentration of ammonia which fit by a regression equation y=7.32x–9.51 (R2=0.98; y, mortality probit scale; x, logarithmic concentration of ammonia), by which 2 h–LC50 value for ammonia was found to be 95.50 mg/L. A linear correla- tion between mortality probit scales and logarithmic concentration of nitrite is also followed the regression equa- tion y=2.86x+0.89 (R2=0.95; y, mortality probit scale; x, logarithmic concentration of nitrite). The regression analysis of toxicity curves showed that the linear correlation between exposed time of ammonia-N LC50 value and ammonia-N LC50 value followed the regression equation y=2 862.85e-0.08x (R2=0.95; y, duration of exposure to LC50 value; x, LC50 value), and that between exposed time of nitrite-N LC50 value and nitrite-N LC50 value followed the regression equation y = 127.15e-0.13x (R2=0.91; y, exposed time of LC50 value; x, LC50 value). The results demonstrate that the tolerance to ammonia in P. bursaria is considerably higher than that of the larvae or juveniles of some metozoa, e.g. cultured prawns and oysters. In addition, ciliates, as bacterial predators, are likely to play a positive role in maintaining and improving water quality in aquatic environments with high-level ammonium, such as sewage treatment systems.

Preliminary Study on Applicability of Microsatellite DNA Primers from Parasite Protozoa Trypanosoma cruzi in Free-living Protozoa

In this paper, we took the lead in studying on specificity of the microsatellite DNA loci and applicability of mi crosatellite DNA primers in protozoa. In order to study characters of microsatellites in free living protozoa, eight microsatellite loci primers developed from Trypanosoma cruzi (MCLE01, SCLE10, MCLE08, SCLE11, MCLF10, MCLG10, MCL03, MCL05) were employed to amplify microsatellite in four free living protozoa, including Bodo designis, Euglena gracilis FACHB848, Paramecium bruzise and Tetrahymena thermophila BF1. In the amplification systems of P. bruzise, four loci (SCLE10, SCLE11, MCLF10, MCL03) were amplified successfully, and four amplification fragments were in proper size. In genome of E. gracilis FACHB848, five of eight primers brought five clear amplification bands. In B. designis, three (No.4, 5 and 7) of eight loci produced clear and sharp products without stutter bands, whereas no bands appeared in T. thermophila BF1. Further, eight 300-500 bp amplification fragments were cloned and sequenced. Nevertheless, all sequenced products did not contain corresponding microsatellite sequence, although Bodo is in the same order and has the nearest phylogenetic relation with Trypanosoma among these four species. Thus, the microsatellite DNA primers can not be applied among order or more far taxa, and the specificity of microsatellite DNA is very high in protozoa. The results of this study will contribute to our understanding of microsatellite DNA in protozoa.

Spatio-temporal variability of periphytic protozoa related to environment in the Niyang River,Tibet,China

The Niyang River, a main tributary of the Yarlung Zangbo River, is an important and typical plateau river ecosystem in Tibet, China. At present, few studies have focused on its aquatic living resources and river ecology. In this study, the composition, abundance, and diversity of periphytic protozoa were investigated across four seasons from 2008 to 2009 to better understand their spatio-temporal patterns and relationship to the environment. Our investigation shows that periphytic protozoa in the Niyang River contained 15 genera, belonged to Tubulinea, Alveolata, Discosea and Rhizaria, Alveolata possessed most genera, up to nine, with highest share in abundance, exceeding 50%, Difflugia and Glaucoma were dominant genera. Moreover, four diversity indices of periphytic protozoa, including species richness, total abundance, Shannon-Wiener diversity index and Pielou's evenness index, displayed a significant descending trend as the seasons continued, in the order of winter, spring, summer and autumn; with a significant difference existing between winter and summer(or autumn) for Shannon-Wiener diversity index and species richness( P <0.05). Four of these diversity indices also presented a V-shaped pattern between the upper middle course of the Niyang River and the confluence of the Niyang River and Yarlung Zangbo River, with the lowest value occurred in the middle course of the Niyang River. However, no significant variation was found through the Niyang River( P >0.05). In addition, canonical correlation analysis(CCA) shows that the densities of Difflugia, Glaucoma is, Enchelydium, Cyphoderia, and Enchelys correlate with water temperature, alkalinity, hardness, pH, and dissolved oxygen, respectively. Lastly, the relationship between periphytic protozoa diversity and the environmental factors of the Niyang River can be predicted using classification and regression trees(CART) annalysis, which suggests that the total abundance and Shannon-Wiener diversity index would be higher when the elevation is above 3 308 m. On the other hand, the Shannon-Wiener diversity index and Pielou's evenness index would be lower when pH and ammoniacal nitrogen have lower or higher values. Finally yet importantly, close attention should be paid to periphytic protozoa and its environment to ensure sustainable development of the Niyang River ecosystem.

西藏热振国家森林公园土壤原生动物群落沿海拔分布格局及其与环境因子的关联特征

土壤原生动物是土壤中一类微型单细胞真核生物,是土壤的关键组成部分,对土壤环境质量动态变化具有重要的指示作用。为了解不同海拔土壤原生动物群落组成、多样性、分布格局及其与环境因子的耦合关系,于2021年7月根据西藏热振国家森林公园地理特征设置了3种不同海拔(低,LA;中,MA;高,HA)共9个样地,采用“非淹没培养法”、“活体观察法”和“Wilbert蛋白银法”对土壤原生动物进行培养和形态学鉴定。结果表明,研究区3种不同海拔共鉴定出土壤原生动物76种,隶属2门12纲23目32科46属,优势纲为动鞭纲(Zoomastigophorea),占总物种数的22.37%。其中,低海拔以动鞭纲为主,中高海拔以肾形纲(Colpodea)占据优势,这与肾形纲的生长方式为R-对策有关。Shannon-Wiener多样性指数、Pielou均匀度指数和Margalef丰富度指数在3种海拔段之间均无显著差异。土壤pH、含水量在低海拔和高海拔间存在差异。共发生网络分析显示,3个不同海拔土壤原生动物物种的共现网络节点间的关系主要为正相关。Mantel分析和冗余分析结果显示,总磷是影响土壤原生动物群落组成的主要驱动因子。该研究结果有助于了解西藏热振国家森林公园生态系统变化,为青藏高原生态环境保护和可持续发展提供基础数据支持。

Effects of physical form of diet on nutrient digestibility, rumen fermentation, rumination,growth performance and protozoa population of finishing lambs

This study was conducted to compare effects of 3 physical forms of feed including mash(diet 1), pellet(diet 2) and complete feed block(CFB; diet 3) on digestion, fermentation and performance of lambs.Twenty-one lambs with an initial average body weight of 26 ± 2.5 kg and 6 ± 1.5 months of age were assigned through a completely randomized design to 3 treatments and 7 replicates. The experimental treatments had the same formulation. The results of present experiment showed that CFB significantly increased feed intake and nutrient digestibility(P < 0.05). There was no significant difference among the diets for rumen fluid pH, blood glucose, concentration of volatile fatty acids(P > 0.05), except acetic acid(P < 0.05). The rumen ammonia nitrogen(NH3-N), mixed rumen protozoa population(RPP), Entodiniums spp., Epidiniums spp., blood urea nitrogen(BUN) concentration, rumination time adjusted for dry matter(DM), neutral detergent fiber(NDF), acid detergent fiber(ADF) intake, and total body weight gain of lambs in CFB diet were the highest among all diets(P < 0.05). Feed conversion ratio at days 31 to 45 and whole experimental period were better in CFB than in other diets(P < 0.05). Overall, according to the findings of the present study, among 3 physical forms of the diets, CFB had the best efficiency due to improvement of nutrient digestibility, rumen fermentation and performance of lambs. Therefore, the CFB diet offers the best result in lambs compared with mash and pellet diets.