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1.
We have examined bacterial indigo reduction to provide a basis for the development of a sustainable alternative to the present chemical methods used to reduce indigo for denim dyeing. Indigo was reduced by Clostridium isatidis, but not by the related Clostridium aurantibutyricum, Clostridium celatum nor Clostridium papyrosolvens. However C. papyrosolvens could, like C. isatidis, reduce the soluble dye, indigo carmine. Of the bacteria examined only the supernatant from C. isatidis cultures decreased indigo particle size. An anthraquinone-rich madder root extract, the soluble anthraquinone-2,6-disulfonic acid and humic acid all stimulated the reduction of indigo by C. isatidis, without affecting the redox potential of the cultures. C. isatidis cultures generated redox potentials from -476 to -602 mV vs SCE, which were about 100 mV more negative than those of the other bacteria examined. The mechanism of bacterial indigo reduction remains unknown, but the unique features of the indigo-reducing C. isatidis indicate possible mechanisms. 相似文献
2.
Wielinga PR de Vries A van der Goot TH Mank T Mars MH Kortbeek LM van der Giessen JW 《International journal for parasitology》2008,38(7):809-817
The protozoan parasite Cryptosporidium is found world-wide and can cause disease in both humans and animals. To study the zoonotic potential of Cryptosporidium in The Netherlands we isolated this parasite from the faeces of infected humans and cattle and genotyped those isolates for several different markers. The overall genotyping results showed: for humans isolates, 70% Cryptosporidium hominis, 19% Cryptosporidium parvum, 10% a combination of C. hominis and C. parvum, and 1% Cryptosporidium felis; and for cattle isolates 100% C. parvum. Analysis of the genetic variants detected for the HSP70, ML1 and GP60 markers showed: for human isolates, one C. hominis and two C. parvum variants (C. parvum and C. parvum NL) for HSP70, one C. hominis and five C. parvum variants (C1, C2, C3, and C2 NL1 and C2 NL2) for ML1, four C. hominis (mainly IbA10G2) and four C. parvum variants (mainly IIaA15G2R1) for GP60; and the cattle isolates only C. parvum (not C. parvum NL1) for HSP70, C1 and C2 for ML1, and 17 different IIa sub-types (mainly IIaA15G2R1) for GP60. Molecular epidemiological analysis of the human data showed a C. hominis peak in autumn. The majority (80%) of the human cases were children aged between 0 and 9 years and >70% of these were caused by C. hominis. Patients >25 years of age were infected mainly with C. parvum. We conclude that C. hominis IbA10G2 is found at high frequencies in autumn in humans and not in cattle. The high prevalence of C. parvum IIaA15G2R1 in both humans and cattle indicates that cattle may be a reservoir for this sub-type in The Netherlands. 相似文献
3.
Zimin Hu Alan T. Critchley Tianxiang Gao Xiaoqi Zeng Steve L. Morrell Delin Duan 《Marine Biology Research》2007,3(3):145-154
Complete nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) sequences were obtained for 18 Chondrus populations collected at 15 sites from eight countries worldwide. Pairwise comparisons with the multiple alignment revealed that intraspecific divergences of ITS sequences ranged from 0.3 to 1.8% in C. crispus Stackhouse (except for the entity SVLH from France) and from 0.0 to 0.6% in C. ocellatus Holmes, whereas interspecific divergences in Chondrus varied from 1.4 to 5.0%. Three phylogenetic methods (neighbour joining, maximum parsimony and maximum likelihood) confirmed three main lineages: the North Atlantic lineage containing entities of C. crispus from Canada, France, Germany, England, Portugal, Ireland and Wales; a second lineage comprising three species: C. sp. 1, C. armatus (Harvey) Yamada et Mikami, and C. pinnulatus (Harvey) Okamura from the Northern Pacific; and a third lineage containing just one species: C. ocellatus from the Northern Pacific. Chondrus yendoi Yamada et Mikami separated from other Chondrus species singly. nrDNA ITS data indicate that a previous assignment of C. sp. 2 to Mazzaella japonica (Mikami) Hommersand may be incorrect, and additional evidence is needed to resolve the generic placement of this entity. It is inferred from the nrDNA ITS data that three Chondrus species are presently known in China with two, C. ocellatus and C. nipponicus, in Qingdao and two, C. armatus and C. nipponicus, in Dalian. We hypothesize that the ancestor of North Atlantic C. crispus had a Pacific origin, and that the present distribution of C. crispus in the Atlantic Ocean correlates with a trans-Arctic dispersal and vicariance events associated with Pleistocene glaciation maxima. 相似文献
4.
High performance liquid chromatography has been used to measure the quantities of caffeine, theobromine, and theophylline in aqueous extracts of endosperm from immature and mature fruits of Coffea arabica and six other species of Coffea. Caffeine was the alkaloid present in largest amounts and, with one exception, in concentrations that were broadly similar in immature and mature fruit. The highest concentrations of caffeine were found in C. canephora at 35.1 and 24.5 mg g−1, respectively, in immature and mature endosperm. The lowest concentrations were in C. bengalensis, where caffeine was not detected in extracts from mature fruit. [8-3H]Caffeine was metabolised relatively slowly by immature endosperm of C. arabica and C. canephora. In contrast, C. dewevrei, C. eugenioides, C. stenophylla, C. salvatrix and C. bengalensis all appeared to metabolise [8-3H]caffeine much more rapidly, as the percentage recovery of the applied label was much lower and there was more extensive incorporation of radioactivity into theobromine, theophylline, 3-methylxanthine and two unidentified polar metabolites. The endogenous caffeine concentrations and the metabolism data indicate that there may be marked differences in the rate of turnover of caffeine in the various species of Coffea. Potential sources of material for the production of naturally decaffeinated coffee are discussed. 相似文献
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The geographic distribution and host range of Capillaria hepatica (Bancroft) (Nematoda) in Australia. 总被引:2,自引:0,他引:2
G. R. Singleton D. M. Spratt S. C. Barker P. F. Hodgson 《International journal for parasitology》1991,21(8):945-957
The geographic distribution, host range and prevalence of Capillaria hepatica were recorded in 4629 house mice, Mus domesticus, 263 black rats, Rattus rattus, and 58 Norway rats, R. norvegicus. The parasite was found at five localities, all in or near large towns along the coast. The two Rattus species appeared to be the primary hosts of C. hepatica in Australia. Published and unpublished data on helminth infections of Australian native mammals from 1162 murids (26 species), 3018 marsupials (67 species) and 99 monotremes (two species) were compiled. Only seven animals from three murid species were infected with C. hepatica; all were from the same rainforest in northern Queensland. C. hepatica was distributed widely, occurring in the house mouse, black rat and Norway rat on a 10,850 ha farm but there was no infection in cattle, sheep or goats (abattoir records). Also, 52 rabbits, four cats and one fox (shot samples) and 27 marsupial mice, Sminthopsis crassicaudata (museum specimens), had no sign of C. hepatica infection. Overall, the results indicate that transmission of C. hepatica to native, domestic and feral mammals is rare, presumably because of ecological constraints on egg embryonation and survival. In the light of these findings, the potential use of C. hepatica as a biological agent to control mouse plagues in Australia is discussed. 相似文献
6.
武夷山保存了典型的中亚热带原生性森林生态系统。由于以往研究的空间和时间尺度较小, 方法规范性不强, 该地区尚缺少大型的、规范的综合性观测和研究平台。本文依托环境保护部南京环境科学研究所等单位按照CTFS调查技术规范建立的武夷山中亚热带常绿阔叶林9.6 ha动态监测样地开展植物群落调查, 从物种组成、区系特征、径级结构和空间分布格局等方面分析了其群落特征。结果表明: 样地内有维管植物68科135属232种, 其中乔木层内胸径≥ 1 cm的植物有44科86属171种。热带性质的科和属分别占总科数和总属数的68.58%和58.83%, 热带特征明显。珍稀濒危物种较多, 有4种国家II级重点保护野生植物、2种《中国生物多样性红色名录——高等植物卷》中的“近危”物种、1种《濒危野生动植物种国际贸易公约》(CITES)附录II物种以及72种中国特有物种, 具有较高的保护和研究价值。稀有种29种, 占总树种数的16.96%。重要值最大的科是壳斗科和山茶科, 二者的重要值之和大于40%。米槠(Castanopsis carlesii)、毛锥(C. fordii)、甜槠(C. eyrei)和少叶黄杞(Engelhardtia fenzlii)的重要值较大, 但没有明显的优势种。小径木较多, 所有个体的平均胸径为5.10 cm, 整体径级分布呈倒J形。乔木层可分为两个亚层, 米槠、毛锥、甜槠等在第I亚层中占优势。米槠和毛锥呈均匀分布, 甜槠、少叶黄杞、赤楠(Syzygium buxifolium)和木荷(Schima superba)呈聚集分布。 相似文献
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Yeasts similar to Candida kruisii were isolated repeatedly from the digestive tracts of basidioma-feeding beetles, especially nitidulids inhabiting and feeding on a variety of agarics in the southeastern USA and Barro Colorado Island, Panama. Based on the identical sequences of the D1/D2 domains of the LSU rRNA gene (rDNA) and host beetle information, the isolates were grouped into 19 genotypes which varied from C. kruisii by up to 38 nucleotide differences in the D1/D2 region. Phylogenetic analysis of rDNA sequences and phenotypic traits placed the isolates in C. kruisii and in nine undescribed taxa. The new species and type strains are designated as Candida pallodes (NRRL Y-27653T), C. tritomae (NRRL Y-27650T), C. panamensis (NRRL Y-27657T), C. lycoperdinae (NRRL Y-27658T), C. atbi (NRRL Y-27651T), C. barrocoloradensis (NRRL Y-27934T), C. aglyptinia (NRRL Y-27935T), C. stri (NRRL Y-48063T), and C. gatunensis (NRRL Y-48064T). A phylogeny based on analysis of a combined database of sequences of SSU and LSU rDNA and the ITS region showed that the nine new species formed a novel sister clade to C. kruisii that was strongly supported by bootstrap analysis. Candida pallodes, C. tritomae, C. panamensis, and C. lycoperdinae formed one subclade, while C. atbi, C. barrocoloradensis, C. aglyptinia, C. stri, and C. gatunensis formed a second distinct subclade within the larger clade. Candida pallodes and C. atbi showed a strong host specificity to beetle species in the genus Pallodes (Coleoptera: Nitidulidae) collected from a variety of agarics. On the other hand, C. panamensis, C. tritomae, and C. lycoperdinae were associated with several unrelated beetles in Erotylidae, Scarabaeidae, Tenebrionidae, and Curculionidae as well as Lycoperdina ferruginea (Nitidulidae). Candida pallodes, C. tritomae, C. lycoperdinae, and C. atbi have been isolated repeatedly in the USA, while the other five new species have been found only at Barro Colorado Island, Panama. 相似文献
10.
Cotesia flavipes Cameron (Hymenoptera: Braconidae) is a gregarious larval koinobiont parasitoid of gramineous stemborers from the Indo-Australian region. More recently, it has been introduced into several countries in East and southern Africa for regulation of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Establishment has varied from country to country and within country, suggesting that abiotic factors, such as temperature and relative humidity, may influence parasitoid performance. In this work, the effect of temperature and relative humidity on life table parameters of two populations of C. flavipes were measured. The results indicated that the factors and their interactions significantly affected the population growth of C. flavipes. The intrinsic rate of increase of the North Pakistan population of Cotesia flavipes was higher than that of the Indian population at all humidities at 28°C, but there were no differences at other temperatures or humidities. 相似文献
11.
Shuai Qi Alex D. Twyford Jun-Yi Ding James S. Borrell Long-Zhen Wang Yue-Ping Ma Nian Wang 《植物分类学报:英文版》2022,60(6):1281-1290
Understanding hybridization and introgression between natural plant populations can give important insights into the origins of cultivated species. Recent studies suggest differences in ploidy might not create such strong reproductive barriers as once thought, and thus studies into cultivated origins should examine all co-occurring taxa, including those with contrasting ploidy levels. Here, we characterized hybridization between Chrysanthemum indicum L., Chrysanthemum vestitum (Hemsley) Ling and Chrysanthemum vestitum var. latifolium (Zhou & Chen), the most important wild species involved in the origins of cultivated chrysanthemums. We analyzed the population structure of 317 Chrysanthemum accessions based on 13 microsatellite markers and sequenced chloroplast trnL-trnF for a subset of 103 Chrysanthemum accessions. We identified three distinct genetic clusters, corresponding to the three taxa. We detected 20 hybrids between species of different ploidy levels, of which 19 were between C. indicum (4x) and C. vestitum (6x) and one was between C. indicum and C. vestitum var. latifolium (6x). Fourteen hybrids between C. indicum and C. vestitum were from one of the five study sites. Chrysanthemum vestitum and C. vestitum var. latifolium share only one chloroplast haplotype. The substantially different number of hybrids between hybridizing species was likely due to different levels of reproductive isolation coupled with environmental selection against hybrids. In addition, human activities could play a role in the different patterns of hybridization among populations. 相似文献
12.
Ovipositional Rhythmicity in Ladybirds (Coleoptera: Coccinellidae): A Laboratory Study 总被引:1,自引:0,他引:1
Omkar Geetanjali Mishra Shefali Srivastava Avanish K. Gupta 《Biological Rhythm Research》2004,35(4):277-287
Complete and diel ovipositional rhythms have been observed in three aphidophagous ladybirds (Coleoptera: Coccinellidae): Coccinella septempunctata Linnaeus, Coccinella transversalis Fabricius and Propylea dissecta (Mulsant) for the first time. The complete ovipositional rhythm could be described in terms of a polynomial curve and daily fluctuations in all three species. In the diel cycle, all three ladybird species oviposited significantly in the scotophase. C. septempunctata females preferred to oviposit at the end of scotophase in the early morning hours (0300-0700), P. dissecta laid most eggs in the middle of scotophase during the night (2100-2300), and C. transversalis laid most at the beginning of the scotophase at dusk (1700-1900). While the diel ovipositional rhythm of C. septempunctata and P. dissecta did not differ between days, that of C. transversalis changed dramatically; there was a single peak on the first and second day of observation, and four oviposition peaks on the fifth day with the peaks being situated in the two hours preceding and succeeding the onset and end of the scotophase. Diel rhythms of C. septempunctata and P. dissecta appear to be endogenous in nature while that of C. transversalis is partly modified by exogenous factors. 相似文献
13.
利用15N硫铵研究了凋落叶多样性对杉木幼苗生长及养分吸收的影响.结果表明,凋落叶多样性的增加有利于盆栽杉木幼苗的生长.杉木、火力楠、红栲和刺楸4种凋落叶混合处理后,杉木幼苗的生长量最大;杉木、火力楠、刺楸3种凋落叶混合处理后的杉木幼苗生长量次之,其它依次为杉木、火力楠、红栲3种凋落叶混合处理>杉木和刺楸凋落叶处理>杉木和红栲凋落叶处理>对照>杉木和火力楠2种凋落叶混合处理>杉木凋落叶处理.就杉木幼苗对硫铵氮的吸收率而言,不作任何处理的杉木幼苗吸收率最高,其次为杉木、火力楠、红栲和刺楸4种凋落叶混合处理,其它依次为杉木、火力楠、刺楸3种凋落叶混合处理和杉木、火力楠、红栲3种凋落叶混合处理>杉木和刺楸凋落叶处理>杉木和红栲凋落叶处理>杉木和火力楠2种凋落叶混合处理>杉木凋落叶处理.另外,用凋落叶处理后,土壤中硫铵氮的残留量比不作凋落叶处理的土壤多,硫铵氮的总回收量也比不作凋落叶处理的土壤大幅增加,而且凋落叶多样性的增加也会增加硫铵氮的残留量. 相似文献
14.
西藏马鹿为我国特有种,曾一度被认定为野外灭绝。在其生境中有多种食性相近的野生有蹄类及家畜同域分布,探究青藏高原特殊环境下西藏马鹿与这些有蹄类的食物资源种间竞争与共存关系十分必要。2013年和2014年8—9月,采用粪便显微分析法确定了桑日县西藏马鹿自然保护区西藏马鹿、白唇鹿、藏原羚、牦牛、山羊草青期食物组成,并比较分析了西藏马鹿与同域野生有蹄类、家畜之间的食物重叠和分化状况。结果表明: 西藏马鹿与其他有蹄类具有相似的可食植物种类组成,但所占食谱比例不同。西藏马鹿主要可食植物多为其他有蹄类次要可食植物,其中弱小火绒草为西藏马鹿(在动物食谱中的百分比为11.2%)与牦牛(10.2%)共同的主要食物,西藏柳为西藏马鹿(9.6%)和白唇鹿(11.4%)共同的主要食物。从科级水平来看,豆科植物为西藏马鹿(21.4%)与藏原羚(42.5%)的共同主要可食植物,莎草科植物为白唇鹿(49.2%)、牦牛(33.4%)、山羊(50.3%)的共同主要可食植物。菊科植物作为西藏马鹿(29.6%)的主要可食植物,也是白唇鹿(7.6%)、藏原羚(11.6%)、牦牛(17.3%)和山羊(14.1%)的次要可食植物。禾本科植物作为西藏马鹿(7.1%)次要可食植物,较其他4种有蹄类(白唇鹿13.6%、藏原羚12.3%、牦牛11.5%、山羊16.0%)所占比例低。西藏马鹿与其他有蹄类食物重叠度均高于0.5,与牦牛的重叠度最高(0.65)。西藏马鹿食物多样性指数(1.32)、均匀度指数(0.37)和生态位宽度指数(15.79)均较高。与2007—2008年相比,西藏马鹿食物组成变化较大,豆科植物比例增大,莎草科植物比例降低,食物质量总体有所提高。西藏马鹿与家畜之间存在较高的食物资源竞争,这将进一步影响西藏马鹿的分布范围和生存空间。 相似文献
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目的:热带假丝酵母以油脂为底物发酵时会产生副产物甘油,研究对热带假丝酵母gk基因进行过表达,将副产物甘油转化为能量,提高油脂转化利用效率。方法:以热带假丝酵母Candida tropicalis 1798中的甘油激酶(gk)为研究对象,利用PCR技术获得同源臂基因gkpR,通过一步法无缝克隆将同源臂和G418抗性基因(kanr)连接至pPICzαA载体,同时将解脂假丝酵母Candida lipolytica 1457中的启动子基因pGAP无缝连接至载体中的gkpR,构成质粒pPICzαA-gkp,并电转化至C.tropicalis 1798感受态细胞中,通过一次同源单交换,将启动子pGK替换为pGAP。结果:经过G418抗性筛选和PCR鉴定,成功获得pGAP基因替换菌株C.tropicalis 1798-gkPr;发酵验证结果显示,启动子基因替换C.tropicalis 1798在以甘油为底物培养时重组菌OD600值比野生型菌株高46.4%,重组菌培养基中甘油剩余量比野生菌降低56.1%,表明启动子替换能促进C.tropicalis1798对甘油的吸收利用。此外,以油脂为底物进行发酵实验时还发现重组菌产长链二元酸的量比野生菌提高32.7%。结论:通过启动子替换手段构建的重组菌C.tropicalis 1798-gkPr,提高了热带假丝酵母对油脂组分中甘油成分的利用效率。 相似文献
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M. T. Burrows S. J. Hawkins A. J. Southward 《Journal of experimental marine biology and ecology》1992,160(2):229-249
Reproduction in Chthamalus montagui Southward and Chthamalus stellatus (Poli) has been compared along gradients of wave exposure and tidal height. The proportion of barnacles carrying egg masses was greatest at low shore levels in both species, although the difference between levels was more pronounced in C. stellatus. Both species were found to breed between the beginning of May and the end of September. The mean number of broods released per season in both species ranged from 1.0 to 2.1 at high shore levels, from 2.2 to 3.2 at mid shore levels, and from 2.6 to 4.4 at low shore levels. C. stellatus predominated low on the shore at an intermediately exposed site and on the mid and low shore at the most exposed site. At these places it produced more broods per year than C. montagui. Development of the embryos of the two species was complete after 3 wk in vivo at 15°C. Eggs containing embryos of C. stellatus were larger than those of C. montagui, and within each species, larger barnacles produced larger eggs. Egg masses of C. stellanus included more eggs than those of C. montagui. Brood size in both species was greatest in shelter and least in exposure. Egg production was, however, similar in the two species when adjusted for differences in body mass. Egg production per unit body mass was greatest at an intermediately exposed site. 相似文献
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Most lichens of the family Teloschistaceae (Ascomycota) produce yellow-orange-red anthraquinone pigments. However, the genus Pyrenodesmia encompasses species in which anthraquinones are absent and replaced by a gray pigment Sedifolia-gray. It was shown recently that these species are related to taxa with both anthraquinones and Sedifolia-gray (Caloplaca xerica group, C. haematites group, and C. cretensis) and to species with a brown pigment instead of both anthraquinones and Sedifolia-gray (C. demissa, C. obscurella, and C. reptans). Nevertheless, relationships between mentioned anthraquinone-containing and anthraquinone-lacking species remained unclear. In total, 8 DNA loci from 41 species were used here to resolve these uncertainties. We concluded that C. demissa, C. obscurella, and C. reptans are rather distant from the core of Pyrenodesmia, and we place them outside of Pyrenodesmia sensu lato. Within Pyrenodesmia sensu lato, three lineages were revealed and recognized on a generic level: the genus Pyrenodesmia sensu stricto (21 species), the genus Kuettlingeria (14 species), which is resurrected here, and the genus Sanguineodiscus (4 species), which is newly described here. The genus Pyrenodesmia includes taxa that never contain anthraquinones, but Sedifolia-gray. It matches with the former C. variabilis group. Taxa of the genera Kuettlingeria and Sanguineodiscus have anthraquinones in their apothecia and Sedifolia-gray in their thalli. The genus Kuettlingeria includes the former C. xerica group plus C. cretensis and C. diphyodes. The genus Sanguineodiscus includes the former C. haematites group and C. bicolor. The identity of Kuettlingeria (Caloplaca) diphyodes was clarified and the name Pyrenodesmia helygeoides was resurrected. Twenty-four new combinations were proposed. 相似文献
18.
Reports of quinolizidine alkaloids in Styphnolobium Schott and Cladrastis Raf. (Leguminosae) conflict with their position in recent molecular phylogenies because they are not members of a major clade of quinolizidine alkaloid-accumulating taxa. The alkaloid status of these two genera was therefore re-investigated using gas chromatography–mass spectrometry. Quinolizidine alkaloids could not be detected in extracts of leaves, flowers or seeds of S. japonicum (L.) Schott, nor in leaves of S. affine (Torrey & A. Gray) Walp., C. delavayi (Franch.) Prain, C. kentukea (Dum.-Cours.) Rudd or C. platycarpa Mak. In contrast, Calia secundiflora (Ortega) Yakovlev, also currently placed outside the major clade of quinolizidine alkaloid-producing genera in molecular phylogenies, was confirmed to accumulate a range of quinolizidine alkaloids. 相似文献
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We describe watershed-scale habitat associations of three Cantharellus species with respect to stand age. During the 1998 autumn fruiting season we collected chanterelle sporocarps from 18 forest stands in and adjacent to the H.J. Andrews experimental forest in the central Cascade Mountains of Oregon. Sampled stands represented two age categories: old growth (350+ y) and 40–60-y-old second growth naturally regenerated from clear-cut harvest. Old growth and second growth stands were spatially paired to reduce the chance of spurious habitat relationships caused by unmeasured correlated variables. We found stand age to be a good predictor of the distribution of C. subalbidus and C. formosus, but only marginally useful for predicting the occurrence of C. cascadensis. The odds that a randomly located chanterelle sporocarp will be C. subalbidus, compared to other chanterelles, are 3–23.5 times higher in old growth than in second growth. Alternatively, there is only a 4–38 % chance that a randomly located sporocarp will be C. formosus in old growth. C. cascadensis was found to be uncommon throughout the study area and showed no significant habitat associations. The abundance of C. cascadensis increased substantially with decreasing elevation indicating that landscape features other than stand age may be more useful in predicting its occurrence. 相似文献