Amino acids and their metabolites in Sarcocystis fusiformis and S. gigantea cysts

It has been established that cysts S. fusiformis and S. gigantea of parasites isolated from the esophagi of infected buffaloes and sheep have the identical set of free amino acids and their metabolites. These species differ from each other in 7 components of 34 studied that points to their metabolic closeness and to specific differences of sarcocysts from different hosts.     

Identification of Synapomorphic Characteris in the Genus Sarcocystis Based on 18S rDNA Sequence Comparison

ABSTRACT. In order to further investigate synapomorphic characters in the genus Sarcocystis , the small subunit ribosomal RNA gene sequences of Sarcocystis capracanis and Sarcocystis moulei were determined and used to infer the phylogenetic position of these two organisms within the cyst-forming coccidia. Phylogenies derived using distance, maximum parsimony and maximum likelihood methods demonstrated that S. capracanis groups with Sarcoystis tenella and Sarcocystis arieticanis as a clade that shares the characteristic of using canids as their definitive host. S. moulei was shown to group with Sarcocystis gigantea and Sarcocystis fusiformis as a clade that shares the characteristic of using felids as their definitive host.     

Identification of Sarcocystis hominis-like (Protozoa: Sarcocystidae) cyst in water buffalo (Bubalus bubalis) based on 18S rRNA gene sequences

DNA templates were extracted from isolates of Sarcocystis hominis-like cysts collected from cattle and water buffalo, as well as from Sarcocystis fusiformis cysts and Sarcocystis suihominis cysts. The 18S rRNA genes were amplified using DNA from a single cyst as the templates. Approximately 1,367-1,440 bp sequences were obtained. The sequence difference in isolates of Sarcocystis hominis-like cysts from water buffaloes, and isolates of S. hominis cysts from cattle were very low, only about 0.1%, much lower than the lowest value (1.7%) among different species. Combined with their morphological structure, these sequence data indicate that the 4 isolates from cattle and water buffalo might be the same species, i.e., S. hominis, suggesting that both cattle and water buffalo may serve as the intermediate hosts for this parasite. Apparently, this is the first report using a single cyst to do such work and is a useful way to distinguish the Sarcocystis cyst in an intermediate host that may be simultaneously infected by several different Sarcocystis species.     

Studies of Sarcocystis in Malaysia. II. Comparative ultrastructure of the cyst wall and zoites of Sarcocystis levinei and Sarcocystis fusiformis from the water buffalo, Bubalus bubalis.

The two species of Sarcocystis--S. levinei and S. fusiformis from the water buffalo, Bubalus bubalis, show some ultrastructural similarities in their cyst wall and zoites. The zoites of both species are of about the same size, banana-shaped and have 22 subpellicular microtubules, numerous micronemes, eight rhoptries, a micropore in the region of the micronemes, an elongated mitochondrion, and a nucleus. S. levinei has 200--300 micronemes and S. fusiformis has about 400. The sarcocysts of both species are trabeculated and their cyst walls have cytophaneres containing annulated fibrils and coarse, electron dense granules. The cytophaneres of S. levinei are sloping, with irregular, wavy outlines, whereas S. fusiformis has the cauliflower-type of cytophaneres. This difference in the appearance of the cytophaneres, together with the difference in size of the sarcocysts and their definitive hosts, further confirms that S. levinei and S. fusiformis are two distinct species in the water buffalo.     

Fine structure and development of Sarcocystis aucheniae in llamas

Isolated cysts of Sarcocystis aucheniae of the llama (Lama glama) were fed to one dog and one cat. Only the dog excreted sporocysts, measuring 13.1-15.7 (15.0 +/- 0.54) X 9.0-11.3 (10.4 +/- 0.36) micron after 11 days for 21 days. A second cat, which had ingested meat of a llama containing macrocysts of S. aucheniae as well as sarcosporidial cysts visible only under a microscope also did not excrete sporocysts. The cysts of S. aucheniae are surrounded by a folded primary cyst wall forming cauliflower-like protrusions into the muscle fibre. The protrusions contain numerous microfilaments. In addition, the primary cyst wall forms numerous tiny vesicles. The parasitized muscle fibre is located in a large cavity within the normal muscle tissue. The cyst wall of S. aucheniae is similarly structured to that of S. gigantea of the sheep.     

Morphological and biochemical correlates in the characterization of Sarcocystis spp

Isoenzyme electrophoretic techniques were applied to the characterization of seven Sarcocystis spp. that had been identified by conventional morphological studies. Cystozoites were harvested from macroscopic cysts from sheep, cattle, and mice and from microscopic cysts from sheep, cattle, and goats. Soluble cystozoite extracts were subjected to cellulose acetate gel electrophoresis and characterized at 15 of the 39 enzyme loci examined. Genetic relationships among isolates were examined by simple phenetic clustering. Two different morphological types of macroscopic cysts from sheep, identified as S. gigantea (syn. S. ovifelis) and S. medusiformis, consistently differed at 40% of the loci examined. Such genetic divergence confirms their separate morphotypic classification. Both differed from microscopic cyst isolates from sheep at 87% of the loci examined; however, two different morphotypes of microscopic cysts were found in the sheep sampled (thick-walled and thin-walled cysts). Until sufficient numbers of each type can be isolated and examined separately, both were regarded as belonging to the species S. tenella (syn. S. ovicanis). Macroscopic and microscopic cysts from cattle consistently differed at 80% of the loci thereby supporting their separate classification as S. hirsuta (syn. S. bovifelis) and S. cruzi (syn. S. bovicanis), respectively. Isolates from goats (microscopic cysts identified as S. capracanis) differed from S. tenella and S. cruzi at 20% and 47% of the loci, respectively. All macroscopic cyst isolates from the various host animal species (including S. muris from mice) differed from each other at nearly all loci. Isoenzyme electrophoretic techniques therefore provided genetic evidence supporting the classification of these various Sarcocystis spp. by their morphological characteristics.     

Genetics, experience, and host-plant preference in Eurosta solidaginis: implications for host shifts and speciation

Host-associated mating is crucial in maintaining the partial reproductive isolation between the host races of Eurosta solidaginis (Diptera: Tephritidae), a fly that forms galls on Solidago altissima and S. gigantea. (We refer to flies reared from S. gigantea as gigantea flies and those reared from S. altissima as altissima flies.) We measured the host preference of males and females of both host races, F1 hybrids between the host races, F2, and backcrosses to both host races. Male and female altissima flies and female gigantea flies had high host fidelity, whereas male gigantea flies had low host fidelity. This result suggests that there may be gene flow between the host races due to nonassortative mating that occurs when male gigantea mate with altissima females on S. altissima. This indicates assortative-mating mechanisms in addition to host-associated mating are required to produce the partial reproductive isolation between the host races that has been observed. Nongenetic factors had no influence on host preference. Larval conditioning did not influence host preference: reciprocal F1 hybrids reared in S. altissima and S. gigantea both preferred S. gigantea. Adult experience had no impact on host preference: females preferred their natal host plant regardless of which host they encountered first as an adult. The hypothesis that maternal effects influence preferences was rejected because male and female flies did not show a consistent preference for the host plant of their mother. We also found no evidence that preference was a sex-linked trait because F1 and backcrosses to the host races with different combinations of X chromosomes from the two host races preferred S. gigantea. Our results indicate that host preference is not determined by a large number of genes because preference of hybrids did not correspond to the proportion of the genome derived from each host race. The strength of the ovipuncture preference for S. gigantea by gigantea females, the females of both reciprocal F1 hybrids, the backcross to gigantea, and F2s indicates that preference is inherited nonadditively at a limited number of loci. The F1 female hybrids, however, had a weaker host preference for S. gigantea than the pure gigantea host race, indicating that there may be incomplete dominance or modifier loci. Males had different host preference patterns than females, with individual male gigantea and male F1 hybrids usually exhibiting preference exclusively for S. gigantea or S. altissima. One hypothesis explaining the difference in host preference between males and females is that the same gene influences both female and male host preference, but it is a sex-influenced gene. Thus, males carrying the gene for S. gigantea preference have an intermediate host preference, whereas females have a strong host preference to S. gigantea. In summary, we found that the host preference that produces host-associated mating is inherited nonadditively at a relatively small number of loci on autosomal genes. This mode of inheritance meets the assumptions of models of sympatric speciation, indicating that the host races could have evolved in sympatry.     

An electron microscopic study of the macro- and microcysts of coccidia in the genus Sarcocystis from buffalo

Two sarcosporidian species from muscles of the water buffalo examined in Azerbaijan were studied. The one making macrocysts was identified as S. fusiformis, whereas the other producing microcysts appeared to be not S. levinei as it might have been expected. Indeed, the microcysts found in the muscles of the buffalo in the slaughterhouse [correction of slaughtery] of Baku differed essentially in morphology of the cyst wall from that of S. levinei, sooner resembling that of S. cruzi from cattle. The cyst wall of these microcysts was seen to make deep invaginations towards the ground substance of cysts. From these invaginations some curved channels were grown outlined with a filamentous material. The described pattern of cyst wall is not characteristic of the S. cruzi sarcocyst. No specification was achieved, and the sarcocysts found in the bubaline muscles are designated as Sarcocystis sp. from the buffalo.     

Sarcocystis Infection in Sheep from South-Western Norway

The occurrence of Sarcocystis infection and pathological changes were recorded in samples of the heart, diaphragm, and oesophagus from 198 healthy sheep representing 3 different age groups, obtained from an abattoir. The infection rate of S. gigantea (syn. S. tenella) was 18.2 %, and the distribution within groups was: ewes 30.0 %, yearlings 11.6 %, lambs nil. The infection rate of S. tenella (syn. S. ovicanis) was 65.1 %, and the corresponding distribution was: ewes 83.5 %, yearlings 74.4 %, and lambs 25.0 %. A third type of Sarcocystis sp. displaying thick wall was found in 3 samples. Focal interstitial infiltrates of mononuclear cells were demonstrated in 47.9 % of the hearts, in 19.6 % of the diaphragms and in 31.3 % of the oesophagi. The occurrence of Sarcocystis and the focal interstitial mononuclear cell infiltrates were positively correlated (P < 0.0001). Morphologically identical sporocysts typical of S. tenella were produced by dogs and foxes fed naturally infected sheep tissues. A cat fed S. gigantea macrocysts produced sporocysts characteristic for the species. Sarcocystis; pathology; life cycle; final hosts; sheep.     

西藏半干旱区3种柏树对干旱胁迫的生理响应特征

以巨柏、大果圆柏和香柏3年生盆栽苗为材料,采用自然干燥法控水,在4个土壤含水量梯度(T1、T2、T3、T4)下测定了3种柏树光合-光响应曲线、光合作用参数和保护酶的活性,以探讨它们对干旱胁迫的生理响应特征。结果显示:(1)3种柏树光合-光响应曲线随干旱胁迫加剧的变化趋势基本相同,当光量子通量密度(PFD)<200μmol.m-2.s-1,净光合速率随PFD的增强基本呈直线增长;当PFD达到1 200μmol.m-2.s-1左右时,净光合速率达到最大。(2)随着干旱胁迫的加剧,3种柏树的光饱和点下降而光补偿点升高,表观量子效率降低;水分利用效率在巨柏和大果圆柏中呈持续下降趋势,而香柏为先上升后下降,但水分利用效率平均值以香柏最大。(3)随着干旱胁迫的加剧,3种柏树SOD活性先升高后降低;巨柏和大果圆柏POD活性呈持续上升趋势,而香柏为先升高后降低;巨柏和大果圆柏的CAT活性先升高后降低,而香柏呈持续上升趋势;3种柏树的MDA含量均呈现逐渐升高趋势,但香柏的脂质过氧化程度远低于巨柏和大果圆柏。研究表明,香柏比巨柏和大果圆柏具有更强的抗旱适应性。     

不同成熟期大秃马勃子实体提取物的抑菌活性及其挥发油成分分析

对不同成熟期大秃马勃Calvatia gigantea子实体的提取物抑菌活性进行了初步研究,并采用水蒸气蒸馏法提取挥发油,利用GC-MS联用仪对成分进行了分析鉴定,还对挥发油的抑菌活性进行了研究。结果表明,对大肠杆菌ATCC8099和金黄色葡萄球菌ATCC6538抑制作用较强的是未成熟大秃马勃的氯仿提取物,浓度为50mg/mL时抑菌率分别为57.57%和50.12%,MIC值均为12.5mg/mL。不同成熟期的挥发油在成分组成上的主要区别是未成熟子实体的挥发油含有雪松醇、α-石竹烯及石竹烯氧化物,而成熟子     

东海原甲藻对羊栖菜合子生长及光合活性的化感作用研究

为评估东海原甲藻(Prorocentrum donghaiense)赤潮发生对羊栖菜(Sargassum fusiformis)幼苗产量的影响并探讨其化感机理,在实验室条件下分别利用浓度为1.00×10⁵cells/mL东海原甲藻活细胞悬浮液(LC)、细胞破碎液(RC)和无细胞滤液(FC)培养羊栖菜合子,并对其生长发育及光合活性进行测定。结果显示,LC、RC和FC均会抑制羊栖菜合子的生长、叶绿素a合成和光合活性,其中FC及LC对合子的抑制程度相似且均大于RC。JIP-test分析表明,FC及LC对合子的最大量子产率(φP_o)、性能指数(PI)及PSⅡ反应中心密度(RCs/ABS)的抑制作用显著大于RC。表明东海原甲藻主要通过向细胞外释放化感物质产生抑制作用,这些化感物质抑制了羊栖菜合子PSⅡ的电子传递,使PSⅡ部分光化学反应中心(RCs)失活,进而使大量激发能转化为热能被耗散掉。而RC中可能含有某些能够刺激羊栖菜合子生长的物质,从而在一定程度上抵消了化感物质的抑制作用。结果表明东海原甲藻对羊栖菜合子的抑制作用主要是由化感物质引起的,东海原甲藻赤潮可以抑制羊栖菜合子的发育和光合活性,减少羊栖菜种苗产量,并最终阻碍了羊栖菜产业的发展。     

东海原甲藻对羊栖菜合子生长及光合活性的化感作用研究

为评估东海原甲藻(Prorocentrum donghaiense)赤潮发生对羊栖菜(Sargassum fusiformis)幼苗产量的影响并探讨其化感机理,在实验室条件下分别利用浓度为1.00×10⁵cells/mL东海原甲藻活细胞悬浮液(LC)、细胞破碎液(RC)和无细胞滤液(FC)培养羊栖菜合子,并对其生长发育及光合活性进行测定。结果显示,LC、RC和FC均会抑制羊栖菜合子的生长、叶绿素a合成和光合活性,其中FC及LC对合子的抑制程度相似且均大于RC。JIP-test分析表明,FC及LC对合子的最大量子产率(φP_o)、性能指数(PI)及PSⅡ反应中心密度(RCs/ABS)的抑制作用显著大于RC。表明东海原甲藻主要通过向细胞外释放化感物质产生抑制作用,这些化感物质抑制了羊栖菜合子PSⅡ的电子传递,使PSⅡ部分光化学反应中心(RCs)失活,进而使大量激发能转化为热能被耗散掉。而RC中可能含有某些能够刺激羊栖菜合子生长的物质,从而在一定程度上抵消了化感物质的抑制作用。结果表明东海原甲藻对羊栖菜合子的抑制作用主要是由化感物质引起的,东海原甲藻赤潮可以抑制羊栖菜合子的发育和光合活性,减少羊栖菜种苗产量,并最终阻碍了羊栖菜产业的发展。     

The dynamics of plant invasions: a case study of three exotic goldenrod species (Solidago L.) in Europe

The patterns of spread of the three exotic species Solidago altissima L., S. gigantea Ait. and S. graminifolia (L.) Salisb. after their introduction to Europe were investigated, based on herbarium specimens and literature records. The spread was analysed by mapping the localities for each decade since 1850. Cumulative numbers of localities as well as numbers of occupied grid squares showed a continuous increase since 1850 for all three species. The slopes, however, were significantly different among the species. Solidago gigantea had the highest colonization rate, followed by S. altissima , and finally S. graminifolia . The latter showed only a slight increase in abundance over time. The increase in diameter of the range in central Europe was logistic for S. altissima and S. gigantea with a rapid increase between 1850 and 1880. The spread of the species in area and time over Europe showed no clear front; new localities at large distances were simultaneously colonized. A large part of the actual range of S. altissima and S. gigantea was already achieved about 1950. It is assumed that the spread of the species followed the hierarchical diffusion model with several independent foci from which the species began to spread. The data suggest that S. altissima and S. gigantea will successfully spread further, leading to an increase in abundance and area, while S. graminifolia seems to spread slowly.     

Purification of c-phycocyanin from Spirulina fusiformis and its effect on the induction of urokinase-type plasminogen activator from calf pulmonary endothelial cells

c-Phycocyanin (c-pc), a blue coloured, fluorescent protein was purified from blue-green alga, Spirulina fusiformis and its effect on fibrinolytic system in vascular endothelial cells was investigated.The c-pc consisted of two subunits, alpha and beta, whose molecular masses were 16 and 17 kDa, respectively. N-terminal sequences of both subunits were well conserved compared with other blue green algal phycobiliproteins. Fibrinolytic activity in the medium conditioned by calf pulmonary arterial endothelial cells was measured by the fibrin plate method.The c-pc increased the fibrinolytic activity in dose- and time-dependent manners. Fibrin zymographic studies indicated that c-pc-induced urokinase-type plasminogen activator in the cells. These in vitro results suggest that c-pc from S. fusiformis is a potent profibrinolytic protein in the vascular endothelial system.     

Two new species and combinations of Stipa L. (Graminae) from northwest Africa

Two new species of Stipa L. S. meridionalis and S. magrebensis, are described from northern Africa, and two new combinations have been made: V. barbata subsp. breripila and S. gigantea subsp. maroccana.     

Isolation and characterization of diazotrophic growth promoting bacteria from rhizosphere of agricultural crops of Korea

Free-living nitrogen fixing bacteria were isolated from rhizosphere of seven different plant namely sesame, maize, wheat, soybean, lettuce, pepper and rice grown in Chungbuk Province, Korea. Five isolates with nitrogenase activity above 150nmol(-1) mg(-1) protein were identified based on, phenotypic and 16S rDNA sequences analysis. The strains were identified as Stenotrophomonas maltophilia (PM-1, PM-26), Bacillus fusiformis (PM-5, PM-24) and Pseudomonas fluorescens (PM-13), respectively. All the isolates produced indole-3-acetic acid (IAA), in the presence of tryptophan, ranging from 100.4 microg ml(-1) (PM-13) to 255 microg ml(-1) (PM-24). The isolate PM-24 (Bacillus fusiformis) exhibiting highest nitrogenase activity (3677.81 nmol h(-1) mg(-1) protein) and IAA production (255microg ml(-1)) has a promising potential for developing as a plant growth promoting rhizobacteria.     

Mitochondrial differentiation, introgression and phylogeny of species in the Tegenaria atrica group (Araneae: Agelenidae)

The relationships between the three members of the Tegenaria atrica group ( T. atrica , T. saeva and T. gigantea ) were examined with DNA sequence data from mitochondrial CO1, 16S rRNA, tRNA^leu(CUN) and ND1 genes. Members of this group of large house spiders have overlapping distributions in western Europe and hybridize with each other to a variable degree. The close relatedness of all three species was supported by all analyses. T. saeva and T. gigantea are more closely affiliated than either is to T. atrica . Haplotypes clearly assignable to T. gigantea were also present in many specimens of T. saeva , suggesting asymmetrical introgression of mtDNA from T. gigantea into T. saeva . Molecular clock calibrations (CO1) suggest that deeper divisions within the genus Tegenaria may be in excess of 10 million years old, and that the evolutionary history of the T. atrica group has been moulded by Quaternary glacial–interglacial cycles.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 79–89.     

Fucoxanthin as the major antioxidant in Hijikia fusiformis, a common edible seaweed

The radical scavenging activity of Japanese edible seaweeds was screened by the DPPH (1-diphenyl-2-picrylhydrazyl) assay to evaluate the DPPH radical scavenging activity in organic extracts. The fresh brown alga Hijikia fusiformis showed the strongest DPPH radical scavenging activity, followed by Undaria pinnatifida and Sargassum fulvellum. The major active compound from Hijikia fusiformis in its acetone extract was identified as fucoxanthin by 13C-NMR spectroscopy.     

Ecological divergence among five co-occurring species of old-field goldenrods

Approximately 130 species of goldenrods are native to North America and many occur sympatrically. Such cooccurrence among closely related species raises the question of whether differences among the species in smallscale distribution and growth forms facilitate their co-occurrence. We investigated five goldenrods that frequently co-occur within their native ranges in Pennsylvania USA old fields. We measured goldenrod abundances, soil textures, nutrients, pH, and moisture within 30 old fields, and determined biomass allocation and flower and seed traits for each goldenrod species at a common site. Ordination revealed that Solidago altissima and S. gigantea were associated with fields having circum-neutral soils, whereas Euthamia graminifolia and S. rugosa achieved their highest abundances on acidic soils. Soil clay content and moisture may be associated with a further separation of species as the abundance of S. altissima tended to be higher on well-drained soils while S. gigantea had a tendency to attain its highest abundances on moist soils that had relatively stable moisture levels over time. Euthamia was more likely to be abundant on clay-rich soils while S. rugosa was often associated with soils containing little clay. Solidago juncea tended to associate with droughty soils that underwent marked soil-moisture changes over time. The latter goldenrod had the greatest absolute and relative root mass, the least absolute and relative leaf mass, highest seed-reproductive allocation, and heaviest achenes. In contrast, S. gigantea and Euthamia, which were often associated with more mesic and stable soil moisture conditions, allocated the least to roots and relatively high amounts of mass to leaves. Solidago gigantea, S. altissima, and Euthamia are invasive species across Europe. The species with the highest colonization rate across Europe, S. gigantea, allocated the most to reproduction in our study, while S. altissima, with the second highest colonization rate, was highly clonal producing the most rhizome mass. Life-history trait variation among goldenrods appears to be linked to differences in small-scale distributions and rates of colonization.