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1.
Seven hundred fifty-four strains of mycobacteria were examined using 97 characters, and a “Hypothetical Mean Organism” (HMO) was prepared for each species using numerical classification. The species could be defined as a group of strains showing a mean S-value of 90% or more to a HMO and showing mean S-values of 89% or less to other HMOs. The following species were recognized: (1) M. tuberculosis, combining M. tuberculosis and M. bovis into one species; (2) M. kansasii; (3) M. novum; (4) M. avium, combining M. avium, M. nonchromogenicum, M. gastri, M. intracellulare and M. scrofulaceum into one species; (5) M. marinum; (6) M. thermoresistibile; (7) M. chitae; (8) M. borstelense; (9) M. abscessus; (10) M. fortuitum; (11) M. phlei; (12) M. aurum; (13) M. parafortuitum; (14) M. lacticola; (15) M. smegmatis. Dendrogram of the species showed two main stems, indicating that the genus Mycobacterium be divided into two subgenera, subgenus Mycobacterium (from M. tuberculosis to M. chitae) and subgenus My cornycobacterium (from M. borstelense to M. smegmatis). Some discrepancy was noted between the results of numerical classification using HMOs and that of the “proper” numerical classification, and this discrepancy is discussed.  相似文献   

2.
Sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (2-ME) activated proteolytic enzymes present in extracts of Entamoeba histolytica and E. invadens; SDS (0.5%) and 2-ME (1.4 and 715 mM) doubled the enzymatic activity when assayed on a stained insoluble substrate. Urea (4 M) did not reduce this activity, suggesting that amebic proteases are stable in the above denaturant conditions. Specific reagents for sulfhydryl (-SH) groups completely inhibited proteolytic activity regardless of pH. Inhibition with alkylating agents, such as N-ethylmaleimide and iodoacetamide, was reversed with 715 mM 2-ME as was also observed with papain. We conclude from these results that the main proteolytic enzymes contained in extracts of E. histolytica and E. invadens are dependent on free thiol groups.  相似文献   

3.
Taxonomic studies of Brazilian Meriania species (Merianieae – Melastomataceae) have identified taxonomic and nomenclatural gaps. The present work proposes one new synonym, M. sanchezii, for M. paniculata; one new neotypification of M. glabra; and five lectotypifications for M. calophylla, M. glabra var. parviflora (= M. glabra), M. paniculata, M. pergamentacea (= M. robusta), and M. urceolata.  相似文献   

4.
A phylogeny of blue butterflies of the genus Maculinea and related genera (Lycaenidae) is proposed, based on 91 morphological and ecological characters. The resulting tree shows that: (1) Phengaris is a derived group nested within Maculinea; (2) the Maculinea‐Phengaris clade is probably nested within Glaucopsyche; (3) there are three well supported groups within the Maculinea‐Phengaris clade: (alcon group ((teleius group) (arion‐Phengaris group))). Some species (M. alcon, M. arionides) appear to be non‐monophyletic and require reclassification. The two alternative strategies of parasitic myrmecophily in the Maculinea‐Phengaris clade, viz., “predatory” and “cuckoo”, seem to be derived characters of the alcon group, and of the teleius and arion‐Phengaris groups, respectively. The common ancestor of Maculinea used dorsal nectary organ secretions for ant attraction, while this trait was reduced in the ancestor of the alcon group and in M. nausithous (of the teleius group). The three recent Maculinea lineages utilize taxonomically diverse host plants, the asterid families Gentianaceae (alcon and arion‐Phengaris groups), Lamiaceae (arion‐Phengaris group), Campanulaceae (arion‐Phengaris group), and the rosid family Rosaceae (teleius group).  相似文献   

5.
Macrobrachium (Bate, 1868) is a large and cosmopolitan crustacean genus of high economic importance worldwide. We investigated the morphological and molecular identification of freshwater prawns of the genus Macrobrachium in South, South West, and Littoral regions of Cameroon. A total of 1,566 specimens were examined morphologically using a key described by Konan (Diversité morphologique et génétique des crevettes des genres Atya Leach, 1816 et Macrobrachium Bate, 1868 de Côte d'Ivoire, 2009, Université d'Abobo Adjamé, Côte d'Ivoire), leading to the identification of seven species of Macrobrachium: M. vollenhovenii (Herklots, 1857); M. macrobrachion (Herklots, 1851); M. sollaudii (De Man, 1912); M. dux (Lenz, 1910); M. chevalieri (Roux, 1935); M. felicinum (Holthuis, 1949); and an undescribed Macrobrachium species M. sp. To validate the genetic basis of the identified species, 94 individuals representing the species were selected and subjected to genetic characterization using 1,814 DArT markers. The admixture analysis revealed four groups: M. vollenhovenii and M. macrobrachion; M. chevalieri; M. felicinum and M. sp; and M. dux and M. sollaudii. But, the principal component analysis (PCA) separated M. sp and M. felicinum to create additional group (i.e., five groups). Based on these findings, M. vollenhovenii and M. macrobrachion may be conspecific, as well as M. dux and M. sollaudii, while M. felicinum and M. sp seems to be different species, suggesting a potential conflict between the morphological identification key and the genetic basis underlying speciation and species allocation for Macrobrachium. These results are valuable in informing breeding design and genetic resource conservation programs for Macrobrachium in Africa.  相似文献   

6.
The phylogenetic systematics of the Gigartinaceae is discussed for seven genera and three undescribed generic lineages and 65 taxa representing 62 species based on an analysis of rbcL sequences and morphological evidence. An examination of rbcL trees resulting from analyses of these taxa identifies seven lineages: (i) ‘Gigartina’ alveata; (ii) Rhodoglossum/Gigartina; (iii) Chondracanthus; (iv) Ostiophyllum; (v) Sarcothalia; (vi) ‘Gigartina’ skottsbergii; and (vii) a large clade containing Iridaea/‘Sarcothalia’, Mazzaella and Chondrus. These lineages and Chondrus are strongly supported; however, two groups, Iridaea/‘Sarcothalia’ and Mazzaella, receive no bootstrap support. The morphology of the female reproductive system is investigated with the aid of computer-generated, color-coded tracings of photographs of cystocarps seen in cross section at different developmental stages. Seven basic cystocarp types were found which corresponded to species groups seen in rbcL trees. These were: (i) a ‘Gigartina’ alveata group in which the carposporangia-bearing filaments develop apomictically from gametophytic cells; (ii) a Rhodoglossum/Gigartina group in which gonimoblast filaments penetrate the surrounding envelope fusing progessively with envelope cells; (iii) a Chondracanthus group in which gonimoblast filaments penetrate the envelope but fuse with envelope cells only at late developmental stages; (iv) a Sarcothalia group in which the gonimoblast filaments displace an envelope composed mainly of secondary gametophytic filaments and link to envelope cells by terminal tubular gonimoblast cells; (v) an Iridaea group similar to the Sarcothalia group, but with an envelope composed of a mixture of medullary cells and secondary gametophytic filaments; (vi) a Mazzaella group that lacks a true envelope and in which gonimoblast filaments connect to modified gametophytic cells by means of terminal tubular cells; (vii) a Chondrus group in which gonimoblast filaments penetrate the medulla and link to modified medullary cells by means of conjunctor cells forming secondary pit connections. The further separation of these groups into genera is based largely on tetrasporangial characters.  相似文献   

7.
Fossil species ofMelanopsis from a freshwater formation in the Jordan Valley (near Al-Qarn) were investigated and the deposits containing these species are formally described as Al-Qarn Formation. Four species were found:Melanopsis buccinoidea Olivier,M. tchernovi Heller & Sivan,M. costata Olivier andM. aaronsohni Blanckenhorn.Melanopsis costata was represented by two groups, “stepped” and “non-stepped”, the latter differing in its lower figurativity index. Intermediates were found betweenM. buccinoidea andM. tchernovi; they may be hybrids. TheMelanopsis assemblage bridges the faunal gap, in the Jordan Valley, between the 2 Ma lake of ‘Erq el Ahmar on the one hand and the 0.8–1.7 Ma lake of ‘Ubeidiya on the other. This suggests an early Pleistocene age of about 1.8 million years for the Al-Qarn Formation.  相似文献   

8.
Cladoceran assemblages in a mineralization gradient   总被引:3,自引:3,他引:0  
Boronat  Loles  Miracle  Maria R.  Armengol  Xavier 《Hydrobiologia》2001,442(1-3):75-88
Cladoceran assemblages were studied in littoral samples from 44 water bodies in Central Spain, showing great differences in salinity and permanence of water. Principal component analyses (PCA) were performed with data on cladoceran relative abundances to identify the main groups of species. Five main groups of species were found, defining the following types of environments: (I) Small but deep hard water lakes (II) permanent but shallow hard water lakes fed by surface springs, rich in macrophytes (III) ephemeral and shallow soft waters lakes (IV) subsaline and hyposaline lakes in their lower range, specially the permanent ones and (V) saline lakes (salinities>6 mg l–1) subject to short or long periods of dryness. The main species constituting these groups were: Group (I): Acroperus neglectus, Alona guttata, Pleuroxus truncatus, Daphnia longispina; group II: Phrixura leei, Latonura rectirostris, Eurycercus lamellatus; Alonella excisa, Daphnia pulicaria; group III: Ephemeroporus phintonicus, Macrothrix rosea, Moina micrura; group IV: Alona rectangula, Ceriodaphnia reticulata, Tetrocephala ambigua, Diaphanosoma mongolianum; group V: Alona salina, Pleuroxus letourneuxi, Dunhevedia crassa, Moina brachiata, Daphnia magna and Daphnia mediterranea. Sample scores from PCA extracted from the correlation matrix of cladoceran proportions were correlated with limnological measurements. Significant correlations with salinity, alkalinity anions and cations indicate that salinity is an important factor in the distribution of the species. However, species assemblages also reflect other factors, such as temporality and littoral development.  相似文献   

9.
Cranial variation was studied across the geographical range of the Meriones meridianus species complex using 665 specimens from 112 localities. Morphometric results were compared with previously published data on genetic variation. Unsupervised model‐based clustering analysis implemented in Mclust software was employed to identify the number and content of morphological clusters. Three clearly defined morphological groups corresponding to mtDNA clades were found. The results of the morphometric analysis are consistent with the hypothesis that these 3 groups should be treated as distinct species; specifically, M. psammophilus Milne‐Edwards, 1871, M. penicilliger Heptner, 1933 and M. meridianus Pallas, 1773. M. psammophilus inhabits the Mongolian–Chinese part of the superspecies range, except for the Mongolian Dzungaria region, which is inhabited by M. meridianus. The range of the latter species extends westwards to north‐west Kazakhstan and Kalmykia. M. penicilliger inhabits the southern part of the superspecies range from Tian Shan to Turkmenistan. M. dahli is craniometrically similar to M. meridianus; hence, its species status remains questionable.  相似文献   

10.
11.
Four new species are described and discussed: from BoliviaM. (sect.Habbasia ser.Setosae)huanchacae; from SE brazilM. (sect.Habbasia ser.Pachycarpae)chiliomera andM. (sect.Mimosa)murex; and from EcuadorM. (sect.Mimosa subser.Polycarpae)Loxensis. The two Brazilian species are illustrated.  相似文献   

12.
Moehringia. sect. Pseudomoehringia McNeill is endemic to the western Mediterranean, having its origin and diversification centre in the Iberian Peninsula and mountains of northern Morocco. Both the relationship with the genus Arenaria as well as the taxonomy within the section have been largely controversial. To disentangle these issues, we conducted a morphometric study using herbarium material. We measured 12 relevant morphological traits from 148 selected herbarium sheets. Data were analyzed using different statistical methods: general linear models, multiple factorial analysis and linear discriminant analysis. We found significant differences between Arenaria balearica and the rest of the genus Moehringia taxa. Within this genus, we identified three well-discriminated species: Moehringia fontqueri, M. glochidisperma and M. intricata. Within M. intricata complex, we discerned virtually no differences amongst most of the subspecies (intricata, giennensis and tejedensis) with the exception of subsp. castellana. We propose: (i) to maintain A. balearica separate from Moehringia sect. Pseudomoehringia; (ii) to consider three species in the section Pseudomoehringia: M. fontqueri, M. glochidisperma and M. intricata; (iii) to recognize only two subspecies within M. intricata complex: subsp. intricata and subsp. castellana. To clarify the taxonomy of this threatened group is of great interest because it might help to prioritize conservation measures.  相似文献   

13.
14.
Inhibition of benzo[a]pyrene (B[a]P)-induced cytotoxicity and cytochrome p450 1A (CYP 1A) activity by flavonoids (1–100 M) was examined in terms of the structure-activity relationship in the human liver-derived cell model (HepG2). Two hydroxyl groups in the 5- and 7-position of flavonoids were essential to inhibit B[a]P-induced cytotoxicity. Generally, flavones (IC50; 5.0–17.2 M) were more potent than the corresponding flavonols (IC50; 42.7–131.8 M), and flavonoids such as apigenin (IC50; 7.2 M) were more active than the corresponding isoflavonoids, genistein (IC50; 61.7 M). The planar structure of flavone proved to be important in inhibiting B[a]P-induced toxicity and CYP 1A activity. The inhibitory effect of flavonoids on B[a]P-induced CYP 1A activity was correlated well with the inhibition of B[a]P-induced cytotoxicity (r=0.635, p<;0.01).  相似文献   

15.
沉水植物化感作用对西湖湿地浮游植物群落的影响   总被引:5,自引:0,他引:5  
通过微宇宙实验,在控制光照和营养盐浓度的条件下分别研究了苦草(Vallisneria spiralis)、金鱼藻(Ceratophyllum demersum)和穗花狐尾藻(Myriophyllum spicatum)的化感作用对采集于杭州西湖湖西湿地的藻类密度、叶绿素a浓度、群落结构、多样性指数等的影响。其结果表明,3种沉水植物对微宇宙系统中的藻类都具有明显影响,藻类密度与叶绿素a浓度受到显著抑制,3个草-藻研究系统中藻类群落结构都发生了变化。在实验末期苦草组、金鱼藻组和穗花狐尾藻组中藻类总生物量(以细胞密度计)分别较初始值降低了37.06%、78.37%和83.40%。栅藻对3种沉水植物的化感作用敏感性较弱。藻类生物多样性方面,穗花狐尾藻系统中最高,其次是金鱼藻组,最后是苦草组,其Shannon-Wiener指数(H)分别为2.76、2.06和0.72,穗花狐尾藻组中H的显著高于苦草组(P0.05)。  相似文献   

16.
Summary Light polarized by reflection was tested in the field for its attractiveness to flying insects. Attracted insects include bugs: some living in water (Corixidae, Notonectidae, Pleidae), others living on its surface (Gerridae) or near it (Saldidae). Beetles were also attracted: some are aquatic (Hydrophilinae, Dytiscidae, Haliplidae, Hydraenidae), others inhabit moist substrates (Sphaeridiinae). Also included are Chironomidae among other nematocerans. Non-polarized reflected light failed to attract any of these insects even at intensities far higher.Three response groups emerge. One is attracted whenever the degree of polarization is high in the UV-range, irrespectively of the degree of polarization in other wavelength ranges, and irrespectively of colour or brightness of the background beneath the polarizing, reflecting surface. The polarization vision of these insects operates in the UV-range. Another group was attracted only by the reflecting surface over a dark background, where the reflected light was highly polarized at all wave-lengths visible to insects. The third group ranges in between.Some Helophorus species behave in spring like members of the first group; in fall, like members of the second group.The distribution of the above response groups within various taxa is provided. Sensory mechanisms and eco-physiological implications are discussed.Abbreviations B matt black surface - b; y; w; a black, yellow white material and aluminum foil, reflection characteristics as described in the text; - G glass - G/b; G/y; G/w; G/a glass panes on different materials - Gb, y, w; Gb, y, Gb types of animals differing in behavior  相似文献   

17.
Ochthebiinae, with c. 650 species distributed worldwide, are the second most speciose subfamily of the aquatic beetle family Hydraenidae. They are ecologically the most diverse hydraenid subfamily, with terrestrial species as well as species in almost all types of aquatic habitats, including hypersaline waters. Ochthebiinae include the tribes Ochtheosini (four species in three genera) and Ochthebiini. We provide here the first comprehensive phylogeny of the tribe Ochthebiini, based on 186 species and four subspecies from most genera, subgenera and species groups. We obtained sequence data for a combination of mitochondrial and nuclear gene fragments including the 5′ and 3′ ends of the cytochrome c oxidase subunit 1, the 5′ end of 16S RNA plus the leucine tRNA transfer plus 5′ end of NADH dehydrogenase subunit I, and internal fragments of the large and small ribosomal units. The analyses with maximum likelihood (ML) and Bayesian probabilities consistently recovered a generally well supported phylogeny, with most currently accepted taxa and species groups as monophyletic. We provide a new classification of the tribe based on our phylogenetic results, with six genera: Meropathus Enderlein, Ochthebius Leach, Protochthebius Perkins, Prototympanogaster Perkins, Tympallopatrum Perkins and Tympanogaster Janssens. The genus Ochthebius is here divided into nine subgenera in addition to Ochthebius s.s.: (1) O. (Angiochthebius) Jäch & Ribera; (2) O. (Asiobates) Thomson; (3) O. (Aulacochthebius) Kuwert; (4) O. (Cobalius) Rey; (5) O. (Enicocerus) Stephens; (6) O. (Gymnanthelius) Perkins comb.n. ; (7) O. (Gymnochthebius) Orchymont; (8) O. (Hughleechia) Perkins comb.n. ; and (9) O. (Micragasma) Sahlberg. Within Ochthebius s.s., 17 species groups are proposed, five of them newly established (3, 9, 11, 13 and 16): (1) andraei; (2) atriceps; (3) corrugatus; (4) foveolatus; (5) kosiensis; (6) lobicollis; (7) marinus; (8) metallescens; (9) nitidipennis; (10) notabilis; (11) peisonis; (12) punctatus; (13) quadricollis; (14) rivalis; (15) strigosus; (16) sumatrensis; and (17) vandykei. We elevated to species rank two subspecies of Ochthebius: O. fallaciosus Ganglbauer stat.n. (former subspecies of O. viridis Peyron) and O. deletus Rey stat.rest. (former subspecies of O. subpictus Wollaston).  相似文献   

18.
Summary Extracellular products of Chlorococcum and Chlamydomonas were isolated from culture filtrates. Five groups of substances were found in both species: (i) steam-volatile acids, (ii) yellow water-soluble phenolic compounds, (iii) lipophilic substances, (iv) proteins and (v) polysaccharides. Chlorococcum had higher concentrations of all groups than Chlamydomonas; moreover, the two species differed slightly in the composition of groups (ii) and (iii). Probably, these is a great similarity between green algae in the production of extracellular compounds.  相似文献   

19.
The Top 10 oomycete pathogens in molecular plant pathology   总被引:4,自引:0,他引:4       下载免费PDF全文
Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant‐pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidis; (2, tied) Phytophthora ramorum; (4) Phytophthora sojae; (5) Phytophthora capsici; (6) Plasmopara viticola; (7) Phytophthora cinnamomi; (8, tied) Phytophthora parasitica; (8, tied) Pythium ultimum; and (10) Albugo candida. This article provides an introduction to these 10 taxa and a snapshot of current research. We hope that the list will serve as a benchmark for future trends in oomycete research.  相似文献   

20.
New α,β-unsaturated ketones 4a,b; 5a–c; and 6a,b; as well as 4-H pyran 7; pyrazoline 8a,b; isoxazoline 9; pyridine 10–11; and quinoline-4-carboxylic acid 12a,b derivatives were synthesized and evaluated for in vitro antitumour activity against HepG2, MCF-7, HeLa, and PC-3 cancer cell lines. Antioxidant activity was investigated by the ability of these compounds to scavenge the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS?+). Compounds 6a, 6b, 7, and 8b exhibited potent antitumour activities against all tested cell lines with [IC50] ?5.5–18.1 µΜ), in addition to significantly high ABTS?+ scavenging activities. In vitro EGFR kinase assay for 6a, 6b, 7, and 8b as the most potent antitumour compounds showed that; compounds 6b, and 7 exhibited worthy EGFR inhibition activity with IC50 values of 0.56 and 1.6?µM, respectively, while compounds 6a and 8b showed good inhibition activity with IC50 values of 4.66 and 2.16?µM, respectively, compared with sorafenib reference drug (IC50?=?1.28?µM). Molecular modelling studies for compounds 6b, 7, and 8b were conducted to exhibit the binding mode towards EGFR kinase, which showed similar interaction with erlotinib.  相似文献   

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