Composition and structure of helminth communities in two populations of Pipistrellus pipistrellus (Chiroptera: Vespertilionidae) from Spain.

The community composition and structure of helminths of Pipistrellus pipistrellus (Schreber, 1774) from two widely separated Spanish localities, El Saler (n = 42) and the San Pedro pothole (n = 34), were determined and compared. Five species of trematodes, Plagiorchis (Plagiorchis) sp., Lecithodendrium (Lecithodendrium) linstowi Dollfus, 1931, Prosthodendrium (Prosthodendrium) sp., Pycnoporus heteroporus (Dujardin, 1845) and Parabascus semisquamosus (Braun, 1900), and one species of cestode, Hymenolepis pipistrelli López-Neyra, 1941, were found. The two bat populations harboured the same helminth species and showed the same trematode dominance, but the most important differences between the two helminth community structures were attributable to L. (L.) linstowi and H. pipistrelli. The mean species richness in the two localities was not significantly different. The mean number of helminth species per infected bat, mean infracommunity abundance and mean infracommunity diversity showed significant differences between both localities. The number of helminths per bat in both populations displayed an aggregated distribution. Results indicate that the different characteristics of the P. pipistrellus foraging area in both localities are important in determining the composition and structure of helminth communities in this bat species. This is the first study of a Palaearctic bat helminth community.     

Potential impacts of clearcutting on parasites of minnows in small boreal lakes

Clearcutting and deforestation lead to increased erosion, increased water temperature, altered water chemistry, and modified watershed hydrology in aquatic systems. Effects on biological organisms have been documented for phytoplankton, zooplankton, benthos, and fish. In this study, parasites of the northern redbelly dace, Phoxinus eos (Cope), were examined from an experimental area consisting of headwater lakes and their watersheds in the boreal forest of Ontario, Canada prior to and after clearcutting around the lakes. Catchments of two lakes were heavily, and one lake partially, clearcut in 1996, and that of a fourth lake was untouched. In 1993, three years prior to clearcutting, five taxa of parasites, including the monogeneans Dactylogyrus sp. and Gyrodactylus sp., metacercaria of the digenean Clinostomum complanatum (Rudolphi, 1819), the nematode Rhabdochona canadensis Moravec et Arai, 1971 and the myxozoan Myxobolus sp. were found in or on northern redbelly dace. In 1998, two years after clearcutting, eight taxa were found on northern redbelly dace, including all of the above plus the digeneans Allocreadium sp. and Ornithodiplostomum ptychocheilus (Faust, 1917) and the copepod Ergasilus lizae Kr?yer, 1863. Mean infracommunity species richness and the maximum number of species per fish were higher in the control and partially cut lake than in the heavily logged lakes. Uninfected fish were found in the heavily cut lakes, but not in the other lakes. Thus, disturbance may reduce parasite infracommunity complexity. Among individual parasite species, R. canadensis was absent from the two most heavily clearcut lakes and abundant in the two other lakes in 1998. Clearcutting may have affected the abundance of certain invertebrates in these lakes, in particular the mayflies that serve as intermediate hosts for R. canadensis. The parasites Allocreadium sp., O. ptychocheilus, and E. lizae have not been previously reported in or on northern redbelly dace.     

Parasite communities of eels Anguilla anguilla in freshwater and marine habitats in Iceland in comparison with other parasite communities of eels in Europe

Ninety-five eels from one marine and three freshwater localities in Iceland were examined for parasites. Twenty species were found, 12 from marine habitat, 12 from freshwater and 4 species were found in both habitats. These are: Eimeria anguillae, Chilodonella hexasticha, Trichodina fultoni, T. jadranica, Myxidium giardi, Myxobolus kotlani, two Zschokkella spp., Derogenes varicus, Deropristis inflata, Diplostonmum sp., Plagioporus angulatus, Podocotyle atomon, Anisakis simplex (larva), Eustrongylides sp. (larva), Hysterothylacium aduncum (larva), Raphidascaris acus (larval and adult stages), Bothriocephalus claviceps, Proteocephalus macrocephalus, and a pseudophyllidean larva. Thirteen of these species are new parasite records from Icelandic waters. The component community of marine eels was characterized by low diversity and a high dominance of a single species. Overall, seven species of helminths were observed, up to five different species occurring in an individual fish. The component community of the freshwater eels was species-poor with low diversity and relatively high dominance of single species. A between-sites difference in the freshwater eels was considerable; only Diplositonun sp. was found at more then one sampling site. Similar to previous studies, there is a total replacement of freshwater macroparasite species by marine ones in saline waters. But unlike research abroad in which species richness decreases with higher salinity, the marine eels in Iceland have considerably higher richness than the freshwater ones. The parasite communities of freshwater eels in Iceland are, in general species-poorer, less diverse and having higher Berger Parker (BP) dominance than other eel communities in Europe. Marine eels have on the other hand comparable species richness, are less diverse and with a high BP dominance.     

Gill parasites of Cephalopholis argus (Teleostei: Serranidae) from Moorea (French Polynesia): site selection and coexistence

The distribution and coexistence of gill ectoparasites of 121 specimens of Cephalopholis argus Bloch et Schneider, caught between October 1994 and October 1995, were investigated. Adults of the monogenean Benedenia sp. and copepod Hatschekia sp., the larval caligid copepod Caligus sp. (copepodite and chalimus stages), and praniza larvae of the isopod Gnathia sp. were found. All species were aggregated within the host population. Infracommunities were poor, with only 40.5% of fish infected by two parasite species. Only two individual fish harboured all the parasite species observed at the component community level. Prevalences were less than 50% and mean intensities were low (less than 6 parasites/host). No dominant parasite species were observed in the host population. The spatial distribution of each parasite species was studied on different partitions of the gill arches. Adult parasite stages that are mobile showed much overlap in their distribution, whereas temporarily attached larvae of Caligidae were more site specific. Copepodite and chalimus larvae showed niche restriction that is probably due to gregarious behaviour. Positive associations between caligid larvae reflected intraspecific interaction for site and/or resources. Each of the Caligus sp. larval stages prefers specific sites, as do the adults, which occur exclusively in the buccal cavity of the host. Infracommunities were too poor and too few to induce processes of interspecific competition.     

Life-cycle of the cestode Wardium calumnacantha (Schmidt, 1963) comb. n. (Hymenolepididae) from common snipe, Gallinago gallinago (L.)

Post-embryonic development of the cestode Wardium calumnacantha (Schmidt, 1963) comb. n., a parasite of common snipe, was studied by experimental infection of the oligochaetes Neoscolex roseus Morev and Rhyacodrilus coccineus (Vejdovsky) carried out in Chukotka. The larvae of W. calumnacantha were ovoid and belonged to the morphological modification of cysticercoid-diplocyst. Two invaginations were observed during the larvogenesis. The first one occurred at the stage of scolexogenesis, when the body of larva was plunged into the external cyst formed by the walls of the primary cavity. Second invagination of the formed scolex and neck into the internal cyst was the final stage of cysticercoid formation.     

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.     

滋生青苔对柑橘叶际生物多样性的影响

本文利用Illumina Miseq高通量测序技术对重庆地区有青苔病症和无病症的柑橘叶际真核生物的群落组成、结构、多样性及差异进行了研究,旨在找到可能的病原物类群,为更好地防治柑橘青苔病奠定基础。结果表明13个柑橘叶片样本共检测到303个OTU,多样性较为丰富;优势门为链形植物门Streptophyta、子囊菌门Ascomycota、绿藻门Chlorophyta等;通过分析发现可能的病原物为不可培养的虚幻球藻属球藻uncultured Apatococcus sp.、黄绿异小球藻Heterochlorella luteoviridis、无柄杯梗孢Cyphellophora sessilis、海南橡胶藻Heveochlorella hainangensis、Coniochaetales sp. GMG C4、椭圆球藻Chloroidium ellipsoideum、Kalinella bambusicola等;不同区县表现出青苔病症状的柑橘叶片上疑似病原物的种类和丰度都差异很大。柑橘青苔病可能是由多种藻类及真菌复合侵染造成的,病原物和柑橘叶片间的相互作用有待进一步研究。     

黄瓜枯萎病菌菌丝际细菌种群丰度变化及其影响黄瓜生长的原因初探

菌丝际细菌存在于真菌与土壤发生强烈反应的狭小区域。连作导致黄瓜枯萎病菌尖孢镰孢菌Fusarium oxysporum f.sp.cucumerinum（Foc）菌丝际细菌种群组成发生变化。本研究根据非连作土（MC）、连作土（SC）中Foc菌丝际细菌类群根瘤菌Rhizobium sp.、无色杆菌Achromobacter sp.、申氏杆菌Shinella sp.和寡养单胞菌Stenotrophomonas sp.在种群中的丰度,设计了相应的含有不同比例细菌的组合HB-1（33：8：7：6）和HB-2（41：12：2：1）。采用平板生测法测定了这4个属的菌丝际细菌代表菌株76、77、252和29的比例变化对黄瓜生长的影响结果表明,用非连作土细菌组合HB-1处理的黄瓜幼苗高于连作土细菌组合HB-2处理。采用"V"字型平板共培养法测定菌株间是否存在互作,并在96孔板中测定了菌丝际细菌培养滤液对其他菌株及自身生长的影响结果表明,4个细菌之间存在互作,菌株76的培养滤液明显促进菌株77的生长,菌株77代谢物抑制其自身生长。在96孔板中测定了4个细菌对黄瓜根分泌物合成培养液中不同碳源的利用能力结果表明,菌株76对各种碳源利用能力最强,菌株252在葡萄糖为主要碳源的根分泌物中生长最好;HB-1组合和HB-2组合在5种不同碳源根分泌物中都能较好生长。对4个菌株产IAA能力的测定结果表明：菌株76的IAA产量较高且持久,最高可达19.4 mg/L,菌株252的IAA产量在60 h达到峰值,最高可达22.1 mg/L;组合HB-1产生IAA能力始终高于组合HB-2。上述结果表明,菌株互作和对黄瓜根分泌物的利用能力是黄瓜枯萎病菌菌丝际细菌种群变化的重要影响因素;菌丝际细菌比例变化影响黄瓜生长,菌株互作产生IAA能力是影响黄瓜生长的重要因子。该研究为维护连作条件下黄瓜健康生长提供了新的线索。     

Genetic characterisation of Giardia duodenalis in dairy cattle in Brazil

The intestinal protozoan parasite Giardia duodenalis (Lambl, 1859) Kofoid & Christiansen, 1915 [syn. Giardia intestinalis and Giardia lamblia] has emerged as a widespread enteric pathogen in humans and domestic animals. In recent years, G. duodenalis has been found in cattle worldwide and longitudinal studies have reported cumulative prevalence of 100% in some herds. In the present study, we determined the prevalence and genetic characterisation of G. duodenalis in 200 dairy cattle from 10 dairy farms in S?o Paulo state, Brazil. All faecal specimens were screened for the presence of G. duodenalis using microscopy examination, enzyme immunoassay (EIA) and polymerase chain reaction (PCR). DNA was extracted from faecal samples and G. duodenalis were identified by amplification of the small subunit ribosomal (SSU-rDNA) and glutamate dehydrogenase (GDH) genes followed by restriction fragment length polymorphism (RFLP) or sequencing analysis. Giardia was identified in eight farm locations (80% prevalence). Overall, 15/200 (7.5%) animals were positive for infection, only one of which was a cow. Giardia duodenalis genotype E was present in 14 of the animals tested. Zoonotic genotype AI was present in one positive sample. Genotype E and genotype A represented 93% and 7% of G. duodenalis infections, respectively. This study demonstrates that G. duodenalis infection was prevalent in dairy calves in S?o Paulo state and that the non-zoonotic genotype E predominates in cattle in this region. Nevertheless, calves naturally infected in Brazil can shed Giardia cysts that can potentially infect humans, and thus, they may represent a public health risk.     

Can a specialist parasite species of a widespread and common host species be rare? The case of Spinitectus inermis (Nematoda: Cystidicolidae) in eels Anguilla anguilla

The claim by many authors that Spinitectus inermis (Zeder, 1800), a narrowly specific parasite of European eels Anguilla anguilla (L.), is a rare species is considered at three levels: its geographical range, its frequency of occurrence compared to other eel parasites and its relative abundance in component communities. The parasite is widely distributed in freshwater throughout the European range of the eel but its occurrence is erratic and unpredictable, being known from only 8 countries. Surveys of eel parasites in the United Kingdom and in Continental Europe show that it is present in only 13% of British and 29% of continental localities. This satisfies one of the criteria for rarity. When present, its prevalence ranges from 1.8% to 43.3%, so it can be considered rare in some localities but in a few it may be common and on occasion it may be the dominant species in the gastro-intestinal community. Populations of S. inermis are almost always characterised by high levels of overdispersion, even at low prevalence. The species also displays an ability to colonise a locality following introduction there. Overall it meets many of the criteria of a rare species including a restricted distribution and a low frequency of occurrence and so it can be considered to exhibit diffusive rarity.     

Lamellodiscus (Monogenea: Diplectanidae) parasites of Dentex macrophthalmus (Teleostei: Sparidae) from the North Atlantic coast of Africa, with a redescription of L. dentexi Aljoshkina, 1984, and description of three new species

Lamellodiscus dentexi Aljoshkina, 1984, a gill parasite of Dentex macrophthalmus (Bloch), is redescribed based on new material from the northwest coast of Africa (Senegal and Morocco). Three new species of Lamellodiscus Johnston et Tiegs, 1922 from D. macrophthalmus are described, Lamellodiscus toguebayei sp. n., L. vicinus sp. n., and L. triacies sp. n., all belonging to the "ignoratus" group. They can be distinguished from all other species of this group by the size and shape of male copulatory organ and sclerotised parts of the haptor. Considering the peculiar morphology of the male copulatory organ (long and thin tube) we propose to put together L. dentexi, L. virgula Euzet et Oliver, 1967 and L. obeliae Oliver, 1973 to form the "elongatus" type within the "elegans" group.     

Diversity of soil bacteria and fungi communities in artificial forests of the sandy-hilly region of Northwest China

Soil erosion is a serious issue in the sandy-hilly region of Shanxi Province, Northwest China. There has been gradual improvement due to vegetation restoration, but soil microbial community characteristics in different vegetation plantation types have not been widely investigated. To address this, we analyzed soil bacterial and fungal community structures, diversity, and microbial and soil environmental factors in Caragana korshinskii Kom., Populus tomentosa Carr., Populus simonii Carr., Salix matsudana Koidz, and Pinus tabulaeformis Carr. forests. There were no significant differences in the dominant bacterial community compositions among the five forest types. The alpha diversity of the bacteria and fungi communities showed that ACE (abundance-based coverage estimator), Chao1, and Shannon indices in C. korshinskii forest were significantly higher than those in the other four forest types (P<0.05). Soil organic matter, total nitrogen, and urease had a greater impact on bacterial community composition, while total nitrogen, β-glucosidase, and urease had a greater impact on fungal community composition. The relative abundance of beneficial and pathogenic microorganisms was similar across all forest types. Based on microbial community composition, diversity, and soil fertility, we ranked the plantations from most to least suitable as follows: C. korshinskii, S. matsudana, P. tabulaeformis, P. tomentosa, and P. simonii.     

艾比湖湿地盐生植物区系研究

对艾比湖湿地盐生植物区系和常见群落的土壤盐分特征进行了分析。结果表明:艾比湖湿地盐生植物物种多样性较为丰富,共有31科73属144种,分别占新疆盐生植物39科128属358种的79.5%、57.0%和40.2%,占中国盐生植物73科239属566种的42.5%、30.5%和25.4%;艾比湖湿地盐生植物地理成分在科的分布有4个类型4个变型;属的分布有9个类型7个变型,其中古地中海成分明显,没有区系特有成分。常见盐生植物群落冠下土壤盐分含量均显著低于裸地,能有效改良盐碱地。     

毒死蜱对南方稻区水域生态效应的室内微宇宙模拟研究

利用浙江诸暨稻田附近池塘底泥和池塘水构建了体积为100 L的室内微宇宙系统,分别以质量浓度为50和5 μg/L的毒死蜱在排沟和池塘中进行单次施药模拟试验,研究了其对水生浮游动物的影响及生态效应。结果表明:浮游动物种群对毒死蜱的敏感性依次为枝角目>桡足类>轮虫类;高浓度处理组中枝角目种群数量在实验结束时未能恢复;桡足类种群数量有所下降,但在施药14 d后开始恢复;轮虫对毒死蜱最不敏感,且由于节肢动物减少,处理组轮虫数量反而出现明显的上升。PRC分析结果表明,毒死蜱对水生浮游动物群落的生态毒性效应与其在微宇宙体系中的浓度相关,且在35 d实验周期内,微宇宙体系中部分生物种群尚难以恢复到正常水平。     

An experimental transmission of porcine strains of Blastocystis sp. in the laboratory mice and gerbils.

Outbred laboratory mice were successfully infected with porcine strains of Blastocystis sp. using faecal stages as well as stages from fresh or passaged cultures. In contrast, inbred BALB/c mice and gerbils were only rarely infected and the intensity of their infection was mostly negligible. Blastocystis sp. was never observed inside the host cells. These results indicate a low host specificity of Blastocystis sp. as well as different sensitivity of investigated hosts to Blastocystis sp. infection.     

黄芪根腐病病株和健株根围微生物菌群变化分析

通过分析黄芪根腐病病株和健株根围微生物菌群的变化,探究根腐病的发病机理,寻找预警病害发生的生物指示因子,为土壤微生态的生物调控提供依据。试验通过菌落计数、PCR-DGGE和16S rRNA V3区基因测序的方法,分析不同年限下黄芪根围病/健土中微生物区系、多样性及群落结构的变化。结果表明:细菌作为黄芪根围土中的优势种群,是影响病土中微生物数量升高的关键因子,其多样性降低是影响病害加重的主要原因之一。假单胞菌属Pseudomonas和无色杆菌属Achromobacter为土壤中的优势菌群,健土中的1号和4号特异条带分别为未培养的假单胞菌Uncultured Pseudomonas sp.和荧光假单胞菌P.fluorescens;6号未培养假单胞菌Uncultured Pseudomonas sp.的丰度与根腐病发病率负相关,16号无色杆菌Achromobacter sp.的丰度则在3年生土壤中显著升高,随后急剧下降。上述4个菌可作为潜在的土壤健康或发病指示因子进一步研究。     

盐碱化梯度上草原植被空间异质性的数量分析

以物种出现的频率(p)作为植被空间分布的观测指标,采用幂函数法则(Power-law)对鄂尔多斯高原不同盐碱化草原上植物群落的空间异质性进行定量研究。结果表明:不同盐碱化梯度上,群落种类结构发生明显改变。轻度、中度、重度盐碱化梯度上出现频率最高的物种分别为羊草、寸草苔、碱蓬。植物群落以中生-旱中生植物为主要建群种;多年生草本植物占有优势;丛生型植物在不同盐碱化梯度上普遍分布,丛生型和分枝型植物分布广泛;种子传播方式为重力传播的物种占有较高比例。物种多样性随盐碱化程度加深而明显下降,均质性增高,不同盐碱区的群落的空间异质性表现出明显差异性,中度退化梯度上生态优势度最高。盐碱退化梯度上的群落变化与种群的繁殖策略、生活史对策、群落的再生产策略等生理与生态特性密切相关。     

Myxobolus buckei sp. n. (Myxozoa), a new pathogenic parasite from the spinal column of three cyprinid fishes from the United Kingdom

Myxobolus buckei sp. n. is described from the spinal column of Leuciscus cephalus (L.), Rutilus rutilus (L.) and Abramis brama (L.) from freshwater rivers in the North of England. The plasmodia develop within the remnants of the embryonic notochord in the intervertebral spaces. The spores are large, measuring (in microm) 14.0 +/- 0.7 x 11.5 +/- 0.6 (mean +/- SD), smooth, round to ellipsoid in valvular view with several sutural edge markings. The polar capsules are pyriform and of equal size, measuring 7.5 +/- 0.5 x 4.2 +/- 0.2 (mean +/- SD), with 11-12 turns of the polar filament arranged perpendicularly to the longitudinal axis of the polar capsule. The parasite has a large intercapsular appendix and large iodinophorous vacuole. The parasite can be differentiated from all known species of Myxobolus Bütschli, 1882 by a combination of the morphological characters defined. Infected fish show marked longitudinal compression of the body compared to uninfected individuals of the same year class, a feature which is pathognomonic for the disease. Histologically, host responses ranged from mild hypertrophy of the zygapophyseal process and expansion of the intervertebral membrane to complete hypertrophy and fusion of the vertebrae. Prominent notochord is present in the intervertebral spaces of infected fish and sporogony of the parasite leads to a vigorous focal inflammatory response involving proliferating fibroblast and osteogenic cells. The parasite causes a radial expansion of the centra and extensive dorsal and ventral outgrowths of the vertebrae leading to compression of the spinal cord and blood vessels running through the neural and haemal spines respectively. The parasite is considered highly pathogenic to juvenile cyprinids.