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1.
The Dimorphandra group, as traditionally circumscribed, is a rather diverse assemblage of genera in Leguminosae subfamily Caesalpinioideae that share certain morphological characteristics with the basally branching lineages of subfamily Mimosoideae. It currently comprises 51 species in seven genera: Burkea (1 species), Dimorphandra (26 species), Erythrophleum (10 species), Mora (6 species), Pachyelasma (1 species), Stachyothyrsus (2 species) and Sympetalandra (5 species). This study investigates the pollen morphology of 25 samples from 19 species of all seven genera. Pollen of the Dimorphandra group is small, isopolar, trizonocolporate and released in monads. Apertures are almost equal to polar length, with correspondingly small apocolpial areas. The shape of the aperture apices varies from acute to wide and rounded. Surface ornamentation is psilate, perforate, microreticulate, or perforate‐rugulate. The wall structure is usually columellate with a well developed foot layer. The pollen is small and unspecialised, agreeing with a previously noted pattern of more fixed and homogenous pollen structure in the more derived clades in subfamily Caesalpinioideae, compared with the great diversity of pollen types found in the basally branching lineages.  相似文献   

2.
Abstract. Sixty-nine characters of larval structure of twenty-eight genera of the supertribe Trechitae (Coleoptera: Carabidae) were analysed phylogenetically. The monophyly of Trechitae is strongly supported with five unique synapomorphies. The monophyly of Zolini + Bembidiini + Pogonini is supported with two synapomorphies. We propose that the tribe Trechini is a sister group to them and its monophyly is supported with two unique synapomorphies. The inferred branching pattern of Trechini genera is (Perileptus + Thalassophilus) + (Amblystogenium + (Trechimorphus + (Trechus + Epaphius + Aepopsis + Trechisibus))); Perileptus is a member of Trechodina rather than Trechina. The monophyly of Zolini is not supported. The monophyly of Pogonini is supported with two unique synapomorphies; its sister group relationships remain obscure; the branching pattern of pogonine genera is (((Pogonus + Pogonistes) + Cardiaderus) + Thalassotrechus). No evidence for monophyly of the tribe Bembidiini (s. lato; including subtribes Bembidiina, Tachyina, Xystosomina, and Anillina) was found. The relationships of Phrypeus are obscure; no evidence could be found linking it with Bembidiina. Without Phrypeus, Bembidiina might be a monophylum with a single synapomorphy. Sinechostictus branches basal of (Bembidion + Asaphidion) and therefore should be treated as a separate genus. Tachyina and Xystosomina form a monophylum based on two unique synapomorphies; a close relationship with a monophyletic Anillina is suggested. Reduction of the number of claws from two to one in Trechitae has taken place twice: within Trechina (Trechus, Epaphius, Aepopsis and Trechisibus) and in (Zolini + Bembidiini + Pogonini). The previously unknown larvae of the isolated genus Phrypeus are described and illustrated. A key to all twenty-eight analysed Trechitae genera based on characters of larvae and a list of larval autapomorphies for each genus are provided.  相似文献   

3.
Passerine spermatozoa exhibit apomorphies that distinguish them from non‐passerine neognaths and palaeognaths. The acrosome is longer than the nucleus (excepting the suboscines, most Corvida, and a few Passerida). A perforatorium and endonuclear canals are absent. The proximal centriole is absent (except in the suboscines). The distal centriole is secondarily short, contrasting with its elongate condition in palaeognaths and Galloanserae. In the Passerida a single mitochondrial strand winds extensively along the axoneme (restricted to the anterior axoneme in suboscines and Corvida). A fibrous, or amorphous, periaxonemal sheath, seen in palaeognaths and many non‐passerines, respectively, is absent. The acrosome in Myrmecocichla formicivora and Philetairus socius is bipartite: an acrosome core is surmounted by an acrosome crest; the core is ensheathed by a layer which is a posterior extension of the crest. The acrosome helix is a lateral extension of the crest and the crest layer with (Myrmecocichla) or without (Philetairus) protrusion of material of the acrosome core into it. In M. formicivora, as in other muscicapoids, a fibrous helix is intertwined with at least the more proximal region of the mitochondrial helix. The fibrous helix is absent at maturity in Philetairus and other described passeroid spermatozoa with the possible exception of Passer italiae. In Philetairus a granular helix precedes the mitochondrial helix.  相似文献   

4.
The review contains a characteristic (with diagnosis) of the genus Anicetus Howard, 1896, a key to the females of the 12 species known from the New World, the Hawaiian Islands, and Australia, and a synopsis of the species with data on their distribution, hosts, biology, ecesis, and use in biological control of injurious coccids. Two new species are described from Mexico: Anicetus myartsevae sp. n. and A. villarreali sp. n. Anicetus carolinensis J. Meyer, 2001 from the USA is excluded from the genus and transferred to Homosemion Annecke, 1967. A new combination is established: Anicetus argentinus (Fidalgo, 1979), comb. n. from Paraceraptrocerus Girault, 1920, which is a synonym of Anicetus. The paper is based on the author’s work in the insect depositories of the USA (Washington, San Francisco, and Riverside), Mexico (Ciudad Victoria), and Russia (St. Petersburg). Anicetus myartsevae sp. n. is compared with the Mexican A. primus (Howard, 1898), from which it differs in the antennal scape half as long dorsally as at base (as long as that in A. primus), the legs more or less extensively dark (mainly yellow in A. primus), and the face with a dark transverse stripe (without stripe in A. primus). Anicetus villarrieli sp. n. is a short-winged species.  相似文献   

5.
A case of somatic instability affecting aleurone colour in a strain of maize from India with flint background was analysed. The somatic instability is localized to theC 1 (Inhibitor) allele ofC locus on the short arm of chromosome 9. Molecular tests indicated thatAc is not present in the Indian stock and the evidence is consistent with the involvement of theEn (Spm) transposable element in the instability. The presence of theEn (Spm)-like element in the stock would suggest that these elements have been present in the maize genome for a long time. A new allele ofshrunken (sh1) gene with a somewhat unorthodox breeding behaviour is also described.  相似文献   

6.
The recognition of species proceeds by two fairly distinct phases: (1) the sorting of individuals into groups or basic taxa (‘discovery’) (2) the checking of those taxa as candidates for species-hood (‘justification’). The target here is a rational reconstruction of phase 1, beginning with a discussion of key terms. The transmission of ‘meaning’ is regarded as bimodal: definition states the intension of the term, and diagnosis provides a disjunction of criteria for recognition of its extension. The two are connected by a spectrum, with purely theoretical definition at one pole and purely ‘operational’ diagnosis at the other, with the more operational elements explained by the more theoretical. The current plethora of species concepts provides a good example. Accepting the Ghiselin–Hull thesis, that a species is an individual, a basic taxon is therefore also an individual with organisms as its parts. In a generalised synchronic individual its parts are conceptually integrated by an integrating principle (IP), which consists of a relation applying within a plan or rule. Fully developed, such an IP ensures the maximisation of the information content of the individual. A diachronic individual is then the set of its component synchronic parts, and its IP is provided by near-identity in an appropriate space-time (not necessarily physical). The integration of parts of an individual is illuminated by Gasking's concept of a proper group (in this case a chain-group), whose members are related by the relation serially fitting together with, the IP completed by an appropriate plan or rule. Gasking also applied the term cluster to a proper group persisting over a substantial period of time, individuated by any member acting as focus. A basic taxon is therefore a cluster of individuals, integrated by the relation significantly taxonomically similar and the rule in character-space-time. The nature of those concepts is discussed and defended. A species will inherit certain of the attributes of the preceding basic taxon (taxa). In at least the synchronic version its parts (individuals) will resemble each other significantly, providing the intuitive applicability of ‘members of’ and ‘instances of’ a species. Also, the notion that a species’ name is given by pure ostension, via a name-bearer (holotype) is empirically incoherent: the name cannot be applied in practice without an appropriate set of diagnostic traits.  相似文献   

7.
Large deletions in Xq21 often are associated with contiguous gene syndromes consisting of X-linked deafness type 3 (DFN3), mental retardation (MRX), and choroideremia (CHM). The identification of deletions associated with classic CHM or DFN3 facilitated the positional cloning of the underlying genes, REP-1 and POU3F4, respectively, and enabled the positioning of the MRX gene in between these genes. Here, we report the cloning and characterization of a novel gene, ribosomal S6-kinase 4 (RSK4; HGMW-approved symbol RPS6KA6), which maps in the MRX critical region. RSK4 is completely deleted in eight patients with the contiguous gene syndrome including MRX, partially deleted in a patient with DFN3 and present in patients with an Xq21 deletion and normal intellectual abilities. RSK4 is most abundantly expressed in brain and kidney. The predicted protein of 746 amino acids shows a high level of homology to three previously isolated members of the human RSK family. RSK2 is involved in Coffin–Lowry syndrome and nonspecific MRX. The localization of RSK4 in the interval that is commonly deleted in mentally retarded males together with the high degree of amino acid identity with RSK2 suggests that RSK4 plays a role in normal neuronal development. Further mutation analyses in males with X-linked mental retardation must prove that RSK4 is indeed a novel MRX gene.  相似文献   

8.
Pluridigite (Pdt) is a semi-dominant mutation obtained after a mutagenesis experiment with ethyl-nitroso-urea (ENU). The mutant exhibits abnormal skeletal pattern formation characterized by the formation of extra digits (polydactyly) in the preaxial (anterior) part of the hindlimbs. The phenotype shows incomplete penetrance, depending on the genetic background. In an F2 cross with C57BL/6, the phenotype could not be associated with a single locus. Strong linkage was observed with markers located on Chromosome (Chr) 12, in a 2-cM interval between D12Mit136 and D12Mit153. This region contains the Twist gene, and we show that the [Pdt] phenotype is dependent upon a new allele of Twist. We further identified that the whole Chr 4 is associated with the [Pdt] phenotype. The Pluridigite phenotype thus results from the combination of a Twist mutant allele and at least two additional loci.  相似文献   

9.
Based on new evidence obtained from freshly collected fossils, we here provide an emendation of Lunzia and Lunzia austriaca with an updated interpretation of the organ architecture, function and affiliation. The specimens reveal that Lunzia austriaca is a pollen organ resembling structures assigned to Weltrichia. Lunzia austriaca comprises cup-shaped pollen organs that develop up to about ten, basally fused lobes carrying appendices. The appendices are arranged pairwise and inserted laterally to a rachis-like structure, in a pinnate architecture on their adaxial side and are interpreted as prominent segments or fertile pinnae that bear numerous synangia identifying them as microsporophylls. The nature of the rachis-like structure is not straightforward. The rachis-like structure could either be fused with a bract – this fused structure then constituting the lobes – or itself been modified depicting a foliate appearance. The microsporophylls are narrow at the base and involute apically or with a sterile apical cowl. Numerous synangia with contracted bases are arranged on the inner (adaxial) side of the microsporophylls in long rows. The synangia consist of presumably four pollen sacs (microsporangia), are oblong and dehisce longitudinally. The pollen is monosulcate, elliptical and with a smooth exine (psilate). It is identified as Monocolpopollenites (=Cycadopites); from the size range, it fits best into Cycadopites accerimus. The architecture and the epidermal anatomy of Lunzia austriaca is discussed and its structure is compared with several contemporary bennettitaleans; sterile foliage and ovulate structures most likely associated with Lunzia austriaca are Pterophyllum filicoides and Westersheimia pramelreuthensis, respectively.  相似文献   

10.
11.
In September 1993 the marine centric diatom, Bellerochea malleus (Brightwell) Heurck, collected in the Wadden Sea near List/Sylt, was parasitized by a Phagomyxa algarum-like organism. Karling (1944) reported Phagomyxa algarum Karling in North Carolina as a parasite of the filamentous brown algae Ectocarpus and Pylaiella. The Bellerochea parasite develops an endocytoplasmic Plasmodium and incorporates host cytoplasm into a large, central digestion vacuole, by a form of phagocytosis. Later on, the Plasmodium cleaves to form a zoosporangiosorus. Each zoosporangium is surrounded by a thin wall. It releases zoospores (2.5 × 4 μm) with two unequal flagella, an anterior (4 μm long) and a posterior (8 μm long). Cystosori and cysts could not be detected. The ultrastructure of the zoosporangia and zoospores was investigated, with particular attention to the flagellar apparatus and its rearrangement during zoospore release. This process is very similar to that recorded for zoospores of the plasmodiophoromycete Polymyxa graminis Ledigham (Barr and Allan, 1982). The Bellerochea parasite is closely related to or identical with Phagomyxa algarum. The taxonomic position of Phagomyxa is discussed. In spite of its phagotrophic nutrition and the possible lack of cystosori and cysts, Phagomyxa should be regarded as a member of the Plasmodiophoromycota (or Plasmodiophorida) but not included in a separate order Phagomyxida as proposed by Cavalier-Smith (1993a).  相似文献   

12.
Huber, B. A. 1994. Copulatory mechanism in Holocnemus pluchei and Pholcus opilionoides, with notes on male cheliceral apophyses and stridulatory organs in Pholcidae (Araneae).—Acta Zoologica (Stockholm) 76: 291–300. The pholcid spiders Holocnemus pluchei (Scopoli, 1763) and Pholcus opilionoides (Schrank, 1781) are investigated with respect to functional morphology of their genital organs using freeze-fixation of spiders during copula in liquid nitrogen and subsequent preparation of histological serial sections of the copulatory organs in functional contact. Special attention is paid to the mode of male pedipalpal arrestation before copulation, which is achieved in two quite different ways: in Pholcus by contact of the lateral cheliceral apophysis with the pedipalpal trochanter-apophysis, in Holocnemus by locking the pedipalpal trochanter between chelicera and pedipalpal coxa. The condition in Pholcus is considered to be apomorphic and to present a synapomorphy of about a dozen genera for which the name “Pholcus-group” is proposed. The stridulatory apparatus of Holocnemus pluchei is described, its biological significance discussed and an overview of accounts on stridulation in Pholcidae given.  相似文献   

13.
The pollen of 30 taxa (27 species, one subspecies and two varieties) in two genera, viz Polygonum s. str. and Polygonella was investigated with LM and SEM, and some selected taxa with TEM. In all genera investigated the pollen is prolate to spheroidal, and the aperture is mostly tricolporate, rarely panto-hexacolporate (especially Polygonum section Polygonum). The exine sculpturing pattern is the most variable feature. Three types of exine can be recognized. Type 1 (Avicularia-Type, sensu Hedberg) - All species of section Polygonum and section Tephis share the smooth tectate exine with spinules, sometimes the surface is more or less rough (Polygonum afromontanum in section Tephis). Type 2 (Pseudomollia-Type, sensu Hong) - Pollen of Polygonum molliaeforme (section Pseudomollia) has the exine, which is verrucose on both poles and nearby the mesocolpium, and mostly psilate around the ectoaperture. Type 3 (Duravia-Type, sensu Hedberg) - Pollen grains of Polygonum section Duravia and Polygonella have the exine which is semitectate-reticulate at the mesocolpium and the poles, and rugulate/reticulate or sometimes foveolate with microspinules around the ectoapertures. The pollen grains in four taxa (viz Polygonum section Pseudomollia, P. section Duravia and genus Polygonella) have a well-marked dimorphism of the ektexine, which is considered to be a synapomorphic condition. The differences of pollen grain between the genus Polygonella and Polygonum section Duravia are almost non existent and clearly interrelated. It is therefore postulated that the similarity in pollen of both taxa is not the result of convergency, but is interpreted as a homology. It is noteworthy that the pollen of Polygonum molliaeforme (section Pseudomollia) appears as intermediate between the Avicularia-type and the Duravia-type, and is well supported the value of separated section for its own. Additionally, in TEM, some exine ultrastructures (e.g. columellae, foot layer, endexine) appear to be valuable characters for comparison between/among taxa. The systematic potentialities of the pollen data of the studied taxa at various systematic levels are also discussed.  相似文献   

14.
Although Cimicifuga foetida L. (Ranunculaceae) has been shown to be a distinct species distributed only in northern Asia (Siberia, Mongolia), the Sino‐Himalayan species C. frigida Royle remains to be much confused with the Chinese endemic C. mairei H. Lév. The independent species status of C. frigida is recognized by some authors, but refuted by others. A cytogeographical study has shown that the ploidy level is well correlated with the geographical distribution of C. frigida and C. mairei. Cimicifuga frigida is a tetraploid (2n = 32) occurring in the Sino‐Himalayan region, whereas C. mairei is a diploid (2n = 16) occurring in central and southwestern China. There is only minor overlap in their geographical distributions in northwestern Yunnan, China. The ploidy level is also well correlated with the morphological characters, in particular the shape of the staminodes, which has previously been used as the only reliable morphological character to distinguish between C. frigida and C. mairei. The cytogeographical pattern, therefore, lends strong support for the recognition of the independent species status of C. frigida. This species is the only polyploid species currently known in the genus.  相似文献   

15.
Several theorems on estimation and verification of linear hypotheses in some Zyskind-Martin (ZM) models are given. The assumptions are as follows. Let y = Xβ + e or (y, Xβ, σ2V) be a fixed model where y is a vector of n observations, X is a known matrix nXp with rank r(X) = r ≦ p < n, where p is a number of coordinates of the unknown parameter vector β, e is a random vector of errors with covariance matrix σ2V, where σ2 is unknown scalar parameter, V is a known non-negative definite matrix such that R(X) ? R(V). Symbol R(A) denotes a vector space generated by columns of matrix A. The expected value of y is Xβ. In this paper four following Zyskind-Martin (ZM) models are considered: ZMd, ZMa, ZMc and ZMqd (definitions in sec. 1) when vector y y1 y2 involves a vector y1 of m missing values and a vector y2 with (n — m) observed values. A special transformation of ZM model gives again ZM model (cf. theorem 2.1). Ten properties of actual (ZMa) and complete (ZMc) Zyskind-Martin models with missing values (cf. theorem 2.2) test functions F are given in (2.11)) are presented. The third propriety constitutes a generalization of R. A. Fisher's rule from standard model (y, Xβ, σ2I) to ZM model. Estimation of vector y1 (cf. 3.3) of vector β (cf. th. 3.2) and of scalar σ2 (cf. th. 3.4) in actual ZMa model and in diagonal quasi-ZM model (ZMqd) are presented. Relation between y? 1 and β is given in theorem 3.1. The results of section 2 are illustrated by numerical example in section 4.  相似文献   

16.
SYNOPSIS. Tritrichomonas muris shares many fine-structural details with the previously described members of the family Trichomonadidae, and especially with the organisms belonging to the subfamily Tritrichomonadinae. Among the features which T. muris has in common with all Trichomonadidae and in all probability with other Trichomonadida are the arrangement and structure of: the kinetosomes; many rootlet filaments, including the sigmoid filaments of kinetosome #2; the parabasal apparatus; and the pelta-axostyle complex. The structures which T. muris-type flagellates share with other Tritrichomonadinae, and especially with Tritrichomonas augusta-type species (including T. foetus), but not with Trichomonadinae that have been studied to date, are: the Type A costa; a comb-like structure, which appears to have replaced the costal base of Trichomonadinae and of Hypotrichomonas; the suprakinetosomal body, rudimentary in T. muris; and the infrakinetosomal body. The undulating membrane, like that of T. augusta-type organisms, consists of a proximal and a distal part. The proximal part, which contains the proximal marginal lamella, is less developed in T. muris than in T. augusta-type flagellates, being represented by a relatively low ridge for the entire length of the organism. The distal part of the membrane in T. muris, on the other hand, is more highly developed; it is a heavy cord, with a distal marginal lamella which consists of a large triangular organelle having a highly ordered structure and 2 less well defined cords distal to this organelle. The tubules of the recurrent flagellum occupy the area distal to the cords. The sigmoid filaments of kinetosome #2, unlike those of other Trichomonadidae examined to date, extend posteriorly to the peltar-axostylar junction; they seem to terminate within the cytoplasm near, but not connected to the axostyle. In addition to the Type A costa, there is a small rootlet filament, which appears to be homologous to the rudimentary costa noted in Hypotrichomonas. Some of the paraxostylar and paracostal granules consist of an outer, relatively dense layer and an inner “core” of moderate density; between the 2 there is a lucent ring. The discussion deals in some detail with the possible nature of the paraxostylar and paracostal granules in trichomonads. The taxonomic status of Tritrichomonas cricetus (Wantland) [Tritrichomonas criceti (Wantland) emend. Levine] and Trichomonas criceti Ray & Sen Gupta is discussed in an appendix; it is concluded that both of these names are synonyms of T. muris (Grassi).  相似文献   

17.
18.
The flagellar root system of zoospores in two species ofChlorosarcinopsis (C. minuta andC. spec.) has been studied in detail. The biflagellate zoospores show a cruciate root system, two of the four microtubular roots containing two microtubules, the other two four microtubules. The flagellar apparatus is otherwise identical with that ofChlamydomonas reinhardi as described byRingo (1967). Evidence is presented that the genusChlamydomonas is characterized by a bilateral symmetric root system (4-2-4-2) rather than a system with four equally numbered roots (i.e. 4-4-4-4). It is suggested that a root system with four identical cruciate roots is not present in any biflagellate algal cell. The taxonomic significance of cruciate root systems in green algae is discussed refering to the identical root systems ofChlorosarcinopsis andChlamydomonas.  相似文献   

19.
Cell walls of each of five bacterial strains belonging to the genus Kribbella (family Nocardioidaceae, order Actinomycetales) contain a neutral polysaccharide (mannan) and teichulosonic acid of novel structure in different proportions. The novel teichulosonic acid found in strains VKM Ac-2500, VKM Ас-2568, VKM Ас-2572, and VKM Ас-2575 is a heteropolymer with an irregular structure where fragments I (predominant) alternate with fragments II (minor):The teichulosonic acid from Kribbella sp. VKM Ac-2527 has in general a structure similar to that above with the exception that the Pse residue is randomly glycosylated at O-4 with β-l-Rhap (along with α-d-Galp3OMe or α-d-Galp2,3OMe). The strain VKM Ac-2572 contained additionally teichuronic acid with the disaccharide repeating unit consisted of aminomannuronic acid and 2,3-diacetamido-2,3-dideoxy-α-glucopyranose. The mannan, a polysaccharide common to all of the strains, is built of (1→6)-linked α-d-mannopyranose substituted with α-d-mannopyranose at O-2. The structures of all the glycopolymers were established by a combination of chemical and NMR spectroscopic methods.  相似文献   

20.
Abstract

Tuberculosis (TB) is a contagious disease caused by Mycobacterium tuberculosis (M.tb) or tubercule bacillus, and H37Rv is the most studied clinical strain. The recent development of resistance to existing drugs is a global health-care challenge to control and cure TB. Hence, there is a critical need to discover new drug targets in M.tb. The members of peptidoglycan biosynthesis pathway are attractive target proteins for antibacterial drug development. We have performed in silico analysis of M.tb MraY (Rv2156c) integral membrane protein and constructed the three-dimensional (3D) structure model of M.tb MraY based on homology modeling method. The validated model was complexed with antibiotic muraymycin D2 (MD2) and was used to generate structure-based pharmacophore model (e-pharmacophore). High-throughput virtual screening (HTVS) of Asinex database and molecular docking of hits was performed to identify the potential inhibitors based on their mode of interactions with the key residues involved in M.tb MraY–MD2 binding. The validation of these molecules was performed using molecular dynamics (MD) simulations for two best identified hit molecules complexed with M.tb MraY in the lipid bilayer, dipalmitoylphosphatidyl-choline (DPPC) membrane. The results indicated the stability of the complexes formed and retained non-bonding interactions similar to MD2. These findings may help in the design of new inhibitors to M.tb MraY involved in peptidoglycan biosynthesis.  相似文献   

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