Attempted Cross-Transmission of Coccidia Between Sheep and Goats and Description of Eimeria ovinoidalis sp. n.

SYNOPSIS.
Attempted infection of 2 young lambs with oocysts of Eimeria christenseni from a goat was unsuccessful. Negative results were obtained also when young kids were fed oocysts of Eimeria ninakohlyakimovae from sheep. There was no difficulty in infecting lambs with the sheep coccidium resembling E. ninakohlyakimovae nor goats with the goat coccidium E. christenseni. Oocysts from the goat measured 38.4 × 26.7 m, but were easily distinguished from Eimeria ahsata from the sheep by sporocyst size and shape, and from Eimeria ovina by oocyst size. Eimeria ninakohlyakimovae -like oocysts from sheep averaged 23.0 ×18.2 m and were morphologically indistinguishable from previously reported goat coccidia.
Since no cross infections of sheep and goats could be accomplished with oocysts of Eimeria sp. characteristic of one or the other host, I concluded that sheep coccidia previously known as E. ninakohlyakimovae are distinct from morphologically similar goat coccidia and therefore constitute a separate species. Since the name E. ninakohlyakimovae was first used for coccidia from the goat, the sheep coccidium is renamed Eimeria ovinoidalis with oocyst structure and endogenous stages similar to those previously described from the sheep.     

Attempted cross-transmission of coccidia between sheep and goats and description of Eimeria ovinoidalis sp. n.

Attempted infection of 2 young lambs with oocysts of Eimeria christenseni from a goat was unsuccessful. Negative results were obtained also when young kids were fed oocysts of Eimeria ninakohlyakimovae from sheep. There was no difficulty in infecting lambs with the sheep coccidium resembling E. ninakohlyakimovae nor goats with the goat coccidium E. christenseni. Oocysts from the goat measured 38.4 X 26.7 microns, but were easily distinguished from Eimeria ahsata from the sheep by sporocyst size and shape, and from Eimeria ovina by oocyst size. Eimeria ninakohlyakimovae-like oocysts from sheep averaged 23.0 X 18.2 microns and were morphologically indistinguishable from previously reported goat coccidia. Since no cross infections of sheep and goats could be accomplished with oocysts of Eimeria sp. characteristic of one or the other host, I concluded that sheep coccidia previously known as E. ninakohlykimovae are distinct from morphologically similar goat coccidia and therefore constitute a separate species. Since the name E. ninakohlyakimovae was first used for coccidia from the goat, the sheep coccidium is renamed Eimeria ovinoidalis with oocyst structure and endogenous stages similar to those previously described from the sheep.     

Experiments with defined multispecific coccidial infections in lambs.

The behaviour of four species of Eimeria was studied in lambs which were given either monospecific or multispecific infections. In the presence of other species the patency of oocyst production of E. ovina and E. weybridgensis was extended and the total number of oocysts produced by all species except E. ninakohlyakimovae was increased. Clinical symptoms were observed only in lambs which received E. ninakohlyakimovae.     

Adaptive divergence and speciation among sexual and pseudoviviparous populations of Festuca

Pseudovivipary is an environmentally induced flowering abnormality in which vegetative shoots replace seminiferous (sexual) inflorescences. Pseudovivipary is usually retained in transplantation experiments, indicating that the trait is not solely induced by the growing environment. Pseudovivipary is the defining characteristic of Festuca vivipara, and arguably the only feature separating this species from its closest seminiferous relative, Festuca ovina. We performed phylogenetic and population genetic analysis on sympatric F. ovina and F. vivipara samples to establish whether pseudovivipary is an adaptive trait that accurately defines the separation of genetically distinct Festuca species. Chloroplast and nuclear marker-based analyses revealed that variation at a geographical level can exceed that between F. vivipara and F. ovina. We deduced that F. vivipara is a recent species that frequently arises independently within F. ovina populations and has not accumulated significant genetic differentiation from its progenitor. We inferred local gene flow between the species. We identified one amplified fragment length polymorphism marker that may be linked to a pseudovivipary-related region of the genome, and several other markers provide evidence of regional local adaptation in Festuca populations. We conclude that F. vivipara can only be appropriately recognized as a morphologically and ecologically distinct species; it lacks genetic differentiation from its relatives. This is the first report of a 'failure in normal flowering development' that repeatedly appears to be adaptive, such that the trait responsible for species recognition constantly reappears on a local basis.     

施肥和刈割对垂穗披碱草（Elymus nutans）、中华羊茅（Festuca sinensis）和羊茅（Festuca ovina）种间竞争力的影响

试验选用青藏高原东部高寒草甸普遍存在的3种禾本科牧草垂穗披碱草(Elymus nutans)、中华羊茅(Festuca sinensis)以及羊茅(Festuca ovina)进行种间竞争的野外研究.通过测定3种牧草生物量的干重,对其进行方差分析并计算了相对产量总和(RYT)以及竞争率(CR).结果如下:对实验物种竞争率(CR)的分析表明垂穗披碱草的竞争力最强,中华羊茅次之,羊茅最差.施肥和刈割处理对于原来的竞争格局没有影响,即在施肥、刈割及其交互作用下3种牧草的竞争等级均是一致的.对试验物种混播的相对产量总和(RYT)的分析表明:在中华羊茅与垂穗披碱草的混播中,两种组成物种利用相同的资源,表现出相互竞争的趋势,这种趋势是非密度依赖的;垂穗披碱草和羊茅混播,在低密度时,羊茅和垂穗披硷草可以共享资源,但是随着密度增加,羊茅和垂穗披碱草表现出竞争相同资源的趋势;在中华羊茅和羊茅的混播中,二者在生长过程中能够共享资源,有相互促进的趋势,表现出共生的关系,且是非密度依赖的.     

A new taxonomic treatment of the Festuca ovina L. aggregate (Poaceae) in the British Isles

A new taxonomic treatment of the Festuca ovina L. aggregate (Poaceae) in the British Isles. A wide range of morphological, anatomical and cytological characters was collected and analysed by a variety of methods, some taxometric. As a result nine species are recognized in the British Isles, one (F. glauca Vill.) only as a garden plant and two (F. huonii Auquier and F. armoricana Kerguélen) only in the Channel Isles. Two other species sometimes claimed for the British Isles (F. guestfalica Boenn. ex Reichb. and F. indigesta Boiss.) are excluded for various reasons given. One species (F. ovina L.) is divided into three subspecies: the diploid subsp. ovina (commonest in the north); and the tetraploid subsp. hirtula (Hackel ex Travis) M. Wilkinson (the commonest taxon of the aggregate in the British Isles) and subsp. ophioliticola (Kerguélen) M. Wilkinson (scattered throughout the British Isles, but commonest on chalk and limestone and not restricted to serpentine soils as once thought).     

A comparison of the susceptibility of Arrhen atherum elatius (L.) beauv. Ex J. C. Presl,Agrostis tenuis sibth,Deschampsia flexuosa and Festuca ovina L. to manganese toxicity

Summary In a solution-culture experiment in a controlled environment, seedlings of four native grasses of contrasted ecology were compared with respect to their response to manganese concentrations over the range 5–200 mg/l. The order of susceptibility to manganese toxicity (Arrhenatherum elatius > Agrostis tenuis > Festuca ovina > Deschampsia flexuosa) is inversely correlated with the ability of these species to colonise acidic soils. re]19760213     

Respiratory costs and rate of protein turnover in the roots of a fast-growing (Dactylis glomerata L.) and a slow-growing (Festuca ovina L.) grass species

Protein turnover is generally regarded as one of the most important maintenance processes in plants in terms of energy requirements. In this study, the contribution of protein turnover to the respiratory costs for maintenance in the roots of two grass species, the fast-growing D. actylis glomerata L. and the slow-growing F. estuca ovina L., is evaluated. Plants were grown under controlled-environment conditions in a nutrient solution to which NO(3)- was added at a relative addition rate of 0.2 and 0.1 mol N mol(-1) N already present in the plant d(-1) for D. glomerata and F. ovina, respectively, so as to obtain a steady exponential growth rate close to the plants' maximum relative growth rate. Pulse-chase labelling with (14)C-leucine was used to determine the rate of protein turnover in the grass roots. The rate of turnover of the total protein pool did not differ significantly between the two species. The protein degradation constant in D. glomerata and F. ovina was 0.156 and 0.116 g protein g(-1) protein d(-1), respectively, which corresponds with a total protein half-life of 4 d and 6 d. Assuming specific respiratory costs for protein turnover of 148 mmol ATP g(-1) protein, the estimated respiratory costs for protein turnover in the roots were 2.8 and 2.4 mmol ATP g(-1) root DM d(-1) in D. glomerata and F. ovina, respectively. Both the fast- and the slow-growing grass spent between 22-30% of their daily ATP production for maintenance on protein turnover, which corresponds to 11-15% of the total root ATP production per day. Note that the data presented in this abstract are based on the assumption that 50% recycling of the (14)C-labelled leucine took place in the roots of both grass species.     

Variation in the Festuca brachyphylla (Poaceae) complex in Svalbard, elucidated by chromosome numbers and isozymes

Contrasting with former taxonomic treatments, chromosome numbers and isozyme data support the delimitation of the seminiferous representatives of the Festuca brachyphylla complex in Svalbard into four species: F. baffinensis, F. brachyphylla, F. hyperborea and F. edlundiae. Unique enzyme markers were found for all species. Festuca brachyphylla proved hexaploid, and the others, tetraploid. The chromosome numbers of F. hyperborea and F brachyphylla (as circumscribed at present) are new to Svalbard. Festuca baffinensis is the most distinct species within the complex, probably representing a separate evolutionary lineage. The three other species seem closely related, showing mutually equidistant relationships. Some deviating plants found on disturbed ground might represent hybrid derivatives or an introduced foreign strain of the elsewhere variable F. brachyphylla. Materials of diploid F. ovina from northern Fennoscandia was enzymatically closely related to the F brachyphylla complex in Svalbard. Festuca brachyphylla, F. edlundiae , and F. hyperborea all had a stronger affinity to F ovina than to F baffinensis , indicating that the F brachyphylla complex is an artificial taxonomic group. There are reasons to believe that the origin of the polyploid taxa of the F brachyphylla complex can be traced to diploid species of the F. brachyphylla and F ovina complexes.     

Root length/leaf area ratios of chalk grassland perennials and their importance for competitive interactions

Abstract. The use of root / shoot ratios to describe allocation of dry weight to structures for capturing soil resources and light is limited due to other functions of the root and shoot such as support and storage. The ratio of fine-root length to leaf area (RLA) provides a better expression of the relative sizes of above-and below-ground exchange surfaces. Dry matter partitioning, leaf area and root lengths were determined for five species of chalk grassland perennial (Carex flacca, Cirsium acaule, Festuca ovina, Leontodon hispidus and Scabiosa columbaria) by extraction of soil cores from an intact sward. The forb species had a greater proportion of their dry matter below-ground. Interspecific variation in values of RLA was considerable, mean values ranging from 137 m/m² in Cirsium acaule to ca. 27 000 m/m² for Festuca ovina. The implications of this interspecific variation in RLA for the competitive interactions in infertile calcareous grasslands are discussed in relation to phenology and internal nutrient cycling.     

Distribution of nematode parasites of the digestive system in sheep (Ovis aries) and goats (Capra hircus) of the Piedmontese and Valdostano Alpine arc

A survey, carried out on gastro-intestinal nematodes of sheep and goats of Piemonte and of Valle d'Aosta (87 sheep and 12 goats) has shown the presence of the following species in sheep, Bunostomum trigonocephalum, Chabertia ovina, Cooperia curticei, Haemonchus contortus, Marshallagia marshalli, Nematodirus abnormalis, Nematodirus filicollis, Nematodirus helvetianus, Nematodirus spathiger, Oesophagostomum venulosum, Ostertagia circumcincta, Ostertagia lyrata, Ostertagia trifurcata, Skrjabinema ovis, Trichostrongylus axei, Trichostronglus colubriformis, Trichostronglus vitrinus, Trichuris ovis and Trichuris skrjabini; in goats, Bunostomum trigonocephalum, Chabertia ovina, Haemonchus contortus, Nematodirus filicollis, Nematodirus helvetianus, Oesophagostomum venulosum, Ostertagia circumcincta, Ostertagia ostertagi, Ostertagia trifurcata, Trichostrongylus axei, Trichostrongylus colubriformis and Trichostrongylus vitrinus. The percentage of each species in the two host is given in the text table.     

The introgression of a functional nuclear gene from Poa to Festuca ovina

In sheep's fescue, Festuca ovina, genes coding for the cytosolic enzyme phosphoglucose isomerase, PGIC, are not only found at the standard locus, PgiC1, but also at a segregating second locus, PgiC2. We have used PCR-based sequencing to characterize the molecular structure and evolution of five PgiC1 and three PgiC2 alleles in F. ovina. The three PgiC2 alleles were complex in that they carried two gene copies: either two active genes or one active and one pseudogene. All the PgiC2 sequences were very similar to each other but highly diverged from the five PgiC1 sequences. We also sequenced PgiC genes from several other grass species. Phylogenetic analysis of these sequences indicates that PgiC2 has introgressed into F. ovina from the distant genus Poa. Such an introgression may, for example, follow from a non-standard fertilization with more than one pollen grain, or a direct horizontal gene transfer mediated by a plant virus.     

青藏高原东缘人工草地群落物种丰富度对杂草入侵的影响

物种丰富度和生态系统功能间的关系是近年来生物多样性研究的中心问题,其中群落抗杂草入侵是其功能的重要表现形式。本文利用青藏高原东缘地区3种野生优良牧草：垂穗披碱草(Elymus nutans)、中华羊茅(Festuca sinensis)和羊茅(F. ovina),构建人工草地群落,探讨了物种丰富度与杂草入侵能力间的相互关系及其潜在的作用机理。结果表明：随着群落中物种丰富度的增加,入侵杂草的物种数、秧苗数和生物量均表现为显著下降趋势(P＜0.05);杂草的物种数、秧苗数和生物量间存在极显著的正相关(P＜0.01);群落的物种丰富度与入侵杂草间的负相关关系可能是选择效应和补偿效应共同作用的结果;2004—2007年,群落中入侵杂草的物种数和生物量有增加趋势,而秧苗数的变化趋势不明显。     

Low variability of internal transcribed spacer rDNA and trnL (UAA) intron sequences of several taxa in the Festuca ovina aggregate (POACEAE)

Identification and classification of numerous Festuca species is still a difficult problem due to the close morphological resemblance. The most difficult fine fescues to identify belong to the Festuca ovina aggregate, which is the largest group in the genus Festuca. Many taxons are considered to be separate species based on quantitative taxonomic characters, differences in ploidy level or the structure of sclerenchyma cells. In order to evaluate the taxonomic value of DNA-based markers, sequence analysis of the internal transcribed spacer (ITS1-5.8S-ITS2) region and the chloroplast trnL (UAA) intron was performed in the ten most problematic fine fescues belonging to the Festuca ovina aggregate. Intraspecific ITS variants were found in a single case while in other cases only intragenomic ITS polymorphisms were detected with 1-2 ambiguous positions. Among the sequences of the trnL (UAA) intron even intragenomic polymorphisms were not detected in any of the Festuca species studied. Thus, the results do not support the species status of these ten taxa.     

Partitioning of Electrons between the Cytochrome and Alternative Pathways in Intact Roots

To test the hypothesis that the cytochrome pathway is not invariably saturated when the alternative pathway is engaged, we titrated root respiration of several species with KCN (an inhibitor of the cytochrome pathway), both in the absence and presence of an inhibitor of the alternative pathway (salicylhydroxamic acid, SHAM). The slopes of the resultant KCN [rho] plots ([rho]cyt) were then used to determine whether the cytochrome pathway was saturated in each species. The species used were Festuca ovina ssp. ovina L., Phaseolus vulgaris L., and six Poa species (Poa pratensis L., Poa compressa L., Poa trivialis L., Poa alpina L., Poa costiniana Vick., and Poa fawcettiae Vick.). Although the cytochrome pathway was saturated in a number of species (i.e. [rho]cyt values were 1.0), several others exhibited [rho]cyt values of less than 0.5. Alternative pathway capacity correlated negatively with [rho]cyt, with [rho]cyt values of less than 1.0 occurring in tissues in which the alternative pathway capacity was greater than 25 to 30% of total respiration. The species that did not show full engagement of the cytochrome pathway rarely exhibited SHAM inhibition in the absence of KCN. We conclude that this lack of SHAM inhibition is not due to a lack of alternative pathway engagement but rather to the diversion of electrons from the alternative pathway to the unsaturated cytochrome path following the addition of SHAM.     

A numerical study of successions in an abandoned,damp calcareous meadow in S Sweden

Summary Two sites at Örup, SE skåne, Sweden, have been investigated, viz. a grazed, unimproved, tussocky pasture on a calcareous moraine clay; and an originally similar, adjacent area that was abandoned about 1960. On the grazed site the vegetation is extremely rich in species. This vegetation type was formerly widespread, but nowadays it is rare and therefore it is important to try to conserve examples of it. In total, 80 0.1 m² quadrates distributed at random within 4 homogeneous plots were investigated. The species composition and the cover, the height of the vegetation, the position on a tussock or in a depression and the amount of litter were recorded. The cover data were ordinated (PCA). The differentiation between tussocks and depressions and the effects of ceasing grazing were clearly separated. The connections between the vegetation and the position of the quadrat, grazing intensity etc. were investigated. The vegetation of the ungrazed parts had become dominated by Filipendula ulmaria and Carex disticha; on an average there were 5.5 species/0.1 m². The grazed quadrats contained three times as many species and showed much higher spatial variation, important species being Carex panicea, C. flacca, Molinia caerulea, Festuca ovina, Potentilla erecta, Centaurea jacea and Serratula tinctoria.Nomenclature of vascular plants follows Lid (1974), for names of bryophytes see Nyholm (1954–69) and Arnell (1956).This paper is mainly based on a more detailed paper in Swedish (Regnéll 1979).I thank Dr. E. van der Maarel, Prof. Nils Malmer, Fil. lic. Anders Larsson, Fil. Dr. Eva Waldemarsson-Jensén and Fil. kand. Stefan Persson for valuable discussions and encouragement.     

高寒草场优势杂草黄帚橐吾水浸液对牧草的化感作用

研究了高寒草场中主要毒杂草——黄帚橐吾水浸液对同域分布的5种牧草的化感作用.将反应指数(RI)相加平均后分为一、二、三级敏感指数,分别评价不同测定指标、不同发育期和物种水平对化感作用的敏感性;从供体角度对相应RI值做同样处理,以综合评价不同水浸液及其不同浓度的化感效应.结果表明,5种牧草对黄帚橐吾化感作用的敏感性从强到弱依次为早熟禾>大雀麦>中华羊茅>羊茅>垂穗披碱草;牧草种子萌发期的敏感性强于幼苗生长期,尤以萌发指数受化感作用的影响明显.黄帚橐吾根、叶水浸液对牧草生物测定结果大多达到显著差异水平,物种水平的化感效应均表现为抑制作用,说明雨水淋溶是黄帚橐吾向环境中释放化感物质的途径之一.黄帚橐吾根部化感效应强于叶片,可能与其地下种间激烈的资源竞争有关.化感作用在增强黄帚橐吾生存竞争力、扩大种群和入侵草场中起着不容忽视的作用,可能是黄帚橐吾单优势种群落形成和草场退化的原因之一.     

Mycorrhizal inoculation of cloned hazels by Tuber melanosporum: effect of soil disinfestation and co-culture with Festuca ovina

A pot experiment was conducted to determine the effects of soil disinfestation and presence of Festuca ovina L. on the formation of Tuber melanosporum Vitt. mycorrhizae by Corylus avellana L. Festuca ovina reduced colonization of young hazels by T. melanosporum. Co-culture with F. ovina resulted in necrosis of hazel roots, leading to 33% plant mortality. The surviving hazels were poorly colonized by T. melanosporum and highly colonized by other symbionts. Roots of F. ovina did not seem to attract mycelium or to be infected by T. melanosporum. Relatively poor mycorrhizal colonization developed in non-disinfested soil containing native inoculum of Tuber melanosporum. Mycorrhization by T. melanosporum developed very efficiently in disinfested soil inoculated with a spore suspension with relatively little colonization by competing symbionts. Growth of host plant was also affected.     

Variation in the abundance of fungal endophytes in fescue grasses along altitudinal and grazing gradients

Epichloë festucae, a common fungal symbiont of the genus Festuca (family Poaceae), can provide its host plant with protection against herbivores. However, infection might also be associated with a cost to its host plant. We examined the distribution of Epichloë festucae infection in natural populations of three fescue grasses, Festuca rubra , F. ovina and F. vivipara, on mountains in northern Sweden to determine whether infection frequency varied with reindeer Rangifer tarandus grazing pressure and altitude. Two differently-scaled approaches were used: 1) infection frequency was measured at a local scale along ten elevational transects within a ca 400 km² area and 2) infection frequency was measured on a regional scale along elevational transects on 17 mountains classified as having a history of high or low reindeer grazing pressure. Mean infection frequencies in F. rubra were 10% (vegetative tillers at a local scale), and 23% (flowering culms at a regional scale), and in F. ovina they were 13% (local scale) and 15% (regional scale). Endophyte infection frequency in F. vivipara , was, on average, 12% (local scale) and 37% (regional scale). In F. rubra , infection decreased significantly with increasing altitude at both the local and regional scale, and was positively correlated with grazing pressure. In F. ovina , an opposite trend was found at the regional scale: infection frequency increased significantly with increasing altitude, while no discernible distribution pattern was observed at the local scale. No elevational trends were observed in infection of F. vivipara . These patterns in the distribution of endophyte-infected grasses in non-agricultural ecosystems may be explained by both biotic (grazing) and abiotic factors (altitude). Differences in ecology and life history of the studied grass species may also be of importance for the different results observed among species.