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1.
Notes on Siphonodon celastrineus (Celastraceae). Hydnocarpus sharmae , a new species described recently from Andaman Islands, India, is Siphonodon celastrineus of Celastraceae and not a species of Flacourtiaceae.  相似文献   

2.
Summary A population ofHalictus (S.) tumulorum, a species whose biology is poorly known, was studied in eastern France. The polyphenism was evaluated by comparing a sample of foundresses (1991) with two samples of summer females (1991 and 1992).H. tumulorum is a primitively eusocial species with castes differing only slightly in size, but more in function, and producing numerous males in the first brood. The social level of the species appears rather low.  相似文献   

3.
The acid-base and copper (II) complexing properties of the heteropolynucleotide poly(inosinic)-poly(cytidylic) acid were studied by means of potentiometric, spectrophotometric, CD, and molecular fluorescence titrations in a working aqueous medium of 0.15 M ionic strength at 37°C. The study of the acid-base equilibria has proved the existence of four different species in the pH interval 2–11. Two new species are detected in the presence of copper(II) ion, at acidic and neutral pH values. Spectrophotometric, CD, melting, and fluorescence data were treated with a multivariate curve resolution procedure that allowed the determination of the number of species simultaneously present in each system [acid-base equilibria, copper(II) complexation equilibria], and the estimation of their concentration profiles and of the pure spectra for each species. From the concentration profiles an unambiguous assignment of which species are present at any pH conditions can be made. Furthermore, the knowledge of the pure uv-visible, fluorescence, and CD spectra recovered by the proposed resolution method for each species brings important structural information. When this mathematical approach was applied to the thermal denaturation data, the melting profile and the uv pure spectra for all the different species or conformations formed in the melting process, were calculated. © 1997 John Wiley & Sons, Inc. Biopoly 42: 271–283, 1997  相似文献   

4.
5.
Australian species of Sinella (Sinella) Brook (Collembola: Entomobryidae)   总被引:1,自引:0,他引:1  
Abstract  The Australian subgenus Sinella ( Sinella ) Brook is revised. Two species are recognised. A new species from New South Wales and South Australia, Sinella ( Sinella ) samueli , is described and the widely distributed species Sinella ( Sinella ) termitum Schött is redescribed based on examination of a specimen from the type series and fresh collections from a wide range of localities in south-eastern Australia. New patterns of chaetotaxy for the genus are described from these species.  相似文献   

6.
Legume species distribution and abundance and selected environmental variables were quantified across a complex gradient (varying in both water-holding capacity and fertility) for frequently burned longleaf pine (Pinus palustris)–wiregrass (Aristida stricta) ecosystems. Legumes were present in all months; however, abundance peaked in June and was minimal after killing frosts in October. Legume species were prominent in the flora (43 species encountered) ubiquitous (94% of 2-m2 subplots had at least one legume species), and abundant (nearly 120 000 stems/ha). Although most species were widely distributed throughout the gradient, Lespedeza angustifolia was distinctly associated with the more hydric end of the gradient, while both Petalostemon pinnatum and Galactia microphylla were located in the more xeric extreme. The percentage variation in species that could be accounted for by environmental variation was low (27%). Of the variation that could be accounted for, a number of environmental variables were important, including soil moisture, pine basal area (i.e., light), and bivalent base cations (e.g., Ca2+). Although gradients in resource availability among sites did not affect the distribution of species or abundance of legumes strongly, variation in resources are likely to regulate N2-fixation rates of the various native legume species, and thereby affect ecological functions such as maintenance of N capital and productivity.  相似文献   

7.
The infectivity of Apatemon (Australapatemon) minor cercariae to 7 species of freshwater leech was examined under laboratory conditions. The leech species exposed to infection were; Erpobdella octoculata, Helobdella stagnalis, Glossiphonia heteroclita, Glossiphonia complanata, Hemiclepsis marginata, Piscicola geometra, and Theromyzon tessulatum. Five species were capable of acting as second intermediate hosts. Despite this broad specificity only Erpobdella octoculata and Helobdella stagnalis could be considered to show a high degree of compatibility with the parasite. In these 2 leech species more than 38% of the cercariae successfully penetrated and established metacercarial cyst infections. The leeches Piscicola geometra and Theromyzon tessulatum did not become infected. Close parallels were found between the species order of host utilization determined experimentally and that revealed by a range of field surveys in Britain, Eastern Europe and Russia. This suggests that the order of second intermediate host utilization in the natural environment has, at least in part, a physiological basis. The degree to which different leeches are utilized as hosts may relate to the opportunity which they afford for transmission of A. minor to wildfowl definitive hosts.  相似文献   

8.
The fixation of trans-(NH3)2Cl2 Pt(II) to poly(I)·poly(C) at low rb (< 0.05) leads to the formation of two complexed species. The major species (ca. 82% of bound platinum) involves coordination of platinum to a single hypoxanthine base, while the other species involves coordination of two hypoxanthine bases, which are either far apart on the same strand or on separate poly(I) strands, to the platinum. These same two species are found after reaction with poly(I), as are two other species throughout the entire rb range studied (rb = 0–0.30). The latter two species are assigned to trans-Pt bound to two bases on a poly(I) strand with (a) one or (b) two free bases between the two bound bases. These two species, (a) and (b), account for ca. 35% of the bound platinum, although the 1:1 species remains dominant (ca. 55%). These two additional species are observed at high rb (>0.075) after reaction with poly(I)·poly(C) but as very minor species. They are formed by reaction with melted poly(I) loops. Also at high rb, we have observed a shifted cytidine H5 resonance arising from interaction of trans-Pt with a melted loop of poly(C). Most probably, this arises from an intramolecular poly(I) to poly(C) crosslink. Results from the reaction of trans-Pt with poly(C) are presented for comparison.  相似文献   

9.
A taxonomic review of Phlebotomus (Idiophlebotomus) (Psychodidae)   总被引:1,自引:0,他引:1  
Five known species (asperulus Quate & Fairchild, erebicolus Quate, pholetor Quate & Fairchild, sejunctus Quate, and stellae Quate) of the caverni-colous subgenus Phlebotomus (Idiophlebotomus) are discussed in relation to newly recognized species from West Malaysia and India. P. frondifer n.sp. and P. tubifer n.sp. are described and a key to the adults of all seven species is given. General features of the subgenus are discussed, with particular reference to the functional relationships between the specialized morphology of the mouthparts and the probable bat hosts of these species.  相似文献   

10.
Non-phagocytic NAD(P)H oxidases have been implicated as major sources of reactive oxygen species in blood vessels. These oxidases can be activated by cytokines, thereby generating O(2), which is subsequently converted to H(2)O(2) and other oxidant species. The oxidants, in turn, act as important second messengers in cell signaling cascades. We hypothesized that reactive oxygen species, themselves, can activate the non-phagocytic NAD(P)H oxidases in vascular cells to induce oxidant production and, consequently, cellular injury. The current report demonstrates that exogenous exposure of non-phagocytic cell types of vascular origin (smooth muscle cells and fibroblasts) to H(2)O(2) activates these cell types to produce O(2) via an NAD(P)H oxidase. The ensuing endogenous production of O(2) contributes significantly to vascular cell injury following exposure to H(2)O(2). These results suggest the existence of a feed-forward mechanism, whereby reactive oxygen species such as H(2)O(2) can activate NAD(P)H oxidases in non-phagocytic cells to produce additional oxidant species, thereby amplifying the vascular injury process. Moreover, these findings implicate the non-phagocytic NAD(P)H oxidase as a novel therapeutic target for the amelioration of the biological effects of chronic oxidant stress.  相似文献   

11.
Sorocarpus Pringsh. is a later synonym forBotrytella Bory. Four species of the genus are known from northern European coasts. Three of them are found at Helgoland (North Sea), type locality of bothBotrytella uvaeformis (Pringsh.) andB. reinboldii (Reinke). A third species, most frequently seen, still remains unnamed. Plants of similar habit, however, have been described from Japan. The type species for the genus,Botrytella micromora Bory, was originally published asEctocarpus siliculosus β.uvaeformis by Lyngbye. A sample from Danish waters proved to be identical with it. In a previous paper (Kornmann & Sahling, 1984), the life history of two species was studied and the investigation is now extended to include the other two, demonstrating the conformity of the four species with the genus characters as to morphological and developmental features.   相似文献   

12.
A new nematode species, Freitascapillaria moraveci n. sp., is described; it was obtained from specimens recovered from the gall bladder of the 2-spot livebearer Heterandrá bimaculata (Heckel, 1848) from La Antigua River, State of Veracruz, Mexico. The new species is assigned to Freitascapillaria Moravec 1982; it is largely characterized by the posterior end of the males, which is laterally expanded without distinct projections. Freitascapillaria moraveci n. sp. differs from the only other species of the genus, F. maxillosa, by the absence of wing-like cells at the esophago-intestinal junction, which are present in the latter species; stichosoma consists of 30-36 stichocytes (F. moraveci) versus 40-60 stichocytes (F. maxillosa) in both males and females and the presence of a well-developed spicule.  相似文献   

13.
The taxonomic status of petrels from the North East Atlantic has long been a matter of debate. Breeding colonies of petrels occurring on the islands of Madeira, Bugio and Cape Verde were originally thought to be outlying populations of the polytypic species Pterodroma mollis . Subsequent taxonomic treatments have varied considerably in their classification of birds from these islands. The petrel populations on Madeira and Bugio represent some of Europe's rarest breeding birds and their exact species designation, and hence relation to conservation mandates, is a question of considerable importance. In this study we use molecular techniques alongside more traditional taxonomic characters to confirm the existence of two species of the genus Pterodroma in the Archipelago of Madeira. We also discuss identification of these species in the field and the implications for their conservation management.  相似文献   

14.
The genusPittosporum includes about 160 species. Four species ofPittosporum occur in the Bonin Islands, and all of these are endemic to the islands. Electrophoretic studies of the four endemic species,P. tobira, from the Japanese mainland, andP. lutchuense var.denudatum from the Ryukyu Islands, were used to determine the origin and speciation pattern of the endemic species. 259 individuals were sampled from ten populations. Twenty loci in nine enzyme systems were resolved and used to calculate the gene frequencies for each population. A low genetic diversity was observed in three of the Bonin Island species, as is reported for other oceanic island plants. The exception,P. boninense, has the largest population size and widest distribution. A dendrogram generated by the UPGMA method shows two clusters. One consists of only the Bonin endemics, suggesting a monophyletic origin for these species.  相似文献   

15.
Between 2000–2002, the structure of communities of lepidopteran larvae was studied in leaf bearing crowns of Quercus cerris in the central and northern part of the Malé Karpaty Mts (SW Slovakia). Caterpillars were collected using the beating method in four study plots. In total, 58 species were found. The families Geometridae, Noctuidae and Tortricidae comprised the highest number of species found. The family Geometridae comprised the highest number of pests. The most abundant species for individual plots were Lymantria dispar, Operophtera brumata, Ypsolopha alpella and Cyclophora ruficiliaria. Most of the recorded species belonged to the trophic group of generalists (39 species). Shannon-Wiener’s diversity index and Pielou’s equitability (evenness) value indicated there were marked differences between the Horny háj study plot (an insular forest with ants as the predators of caterpillars) and other plots. The main ecological gradient along DCA-1 related to the host specificity of caterpillars and consisted of three groups: (a) polyphagous species; (b) specialist species feeding chiefly on oaks or exclusively on oaks and (c) species preferring some oak species, mainly Q. cerris. The fragmentation of growth was identified along DCA-2.  相似文献   

16.
The complex typification and nomenclature of the eight species of Geissorhiza based on Thunberg's Cape collections, is reviewed critically in preparation for a complete revision of the genus. These species, initially assigned to Ixia , were described by Thunberg and von Linné fil., founded on collections of twelve different species. Some well known species require changes to their nomenclature; G. rochensis sensu Ker becomes G. radians (Thunb.) Goldbl.; while Ixia scillaris Thunb. nom. illeg., based on three different species is lectotypified and shown to be G. scillaris Spreng., a species quite distinct from G. juncea , with which it has often been confused. Arguments for considering the name G. secunda illegitimate are reviewed. The species long known by this epithet must be called G. aspera Goldbl. Lectotypes have been designated for G. monanthos, G. radians, G. scillaris and G. setacea , none of which have been satisfactorily typified before.  相似文献   

17.
Twenty-two species of benthic hydroids, belonging to ten families and 14 genera, were found in a hydroid collection obtained in the Balleny Islands during the BioRoss expedition with the NIWA research vessel Tangaroa in 2004. Twenty of those species constitute new records for the Balleny Islands, raising the total number of known species in the area to 25. Most are members of the subclass Leptothecata, although the subclass Anthoathecata is also relatively well represented. Kirchenpaueriidae and Sertulariidae constitute families with the greatest numbers of species in the collection, with five species (20%) each. Oswaldella with five species (20%) and Staurotheca with four (16%), were the most diverse genera. Twelve species (63%) are endemic to Antarctic waters, most of them with a circum-Antarctic distribution, and 17 (89%) are restricted to Antarctic or Antarctic/sub-Antarctic waters. Although the Balleny Islands hydroid fauna seems to be a typical Antarctic assemblage, it has some striking peculiarities, namely the absence or low representation of some typical and widespread Antarctic genera (Antarctoscyphus and Schizotricha/Symplectoscyphus, respectively).  相似文献   

18.
Homoploid hybrid speciation has traditionally been considered a rare event, dependent on the establishment of both a novel, balanced genotype and reproductive isolating barriers between the new species and its progenitors. However, more recent studies have shown that synthetic hybrids converge toward the chromosomal structure of natural hybrids after only a few generations, suggesting that this phenomenon may be more frequent than previously assumed. Here, the possibility that the diploid hybrid species Helianthus deserticola arose from more than one hybrid speciation event was investigated using patterns of variation from cpDNA, 18 nuclear microsatellite loci, and population interfertility. Helianthus deserticola contains cpDNA haplotypes characteristic of both parental species, is polyphyletic with one parental species based on nine microsatellite loci, and has a high degree of interfertility among populations. The data are consistent with either a single origin followed by introgression with the parental species or multiple origins. Analysis of microsatellite variation places the origin of H. deserticola between 170?000 and 63?000 years before present, making it unlikely that anthropogenic disturbances influenced its origin. Finally, the hybrid species generally has lower levels of genetic diversity but higher levels of differentiation among populations than either parental species.  相似文献   

19.
J Zhang  S Wang  H Li  B Hu  X Yang  Z Wang 《PloS one》2012,7(7):e41657
The diffuse coevolution between two moth species (Epicephala lativalvaris and E. mirivalvata) and two plant species (Breynia fruticosa and B. rostrata) is reported based on field observations and indoor experiments conducted in Hainan and Fujian, China. Study results showed that the two Epicephala species jointly pollinated the two Breynia species, which led to a unique obligate pollination mutualism of two-to-two species specificity. A single Epicephala larva exclusively fed on seeds of host plants and developed to maturity by consuming all six seeds of each fruit, whereas a fraction of intact fruits were left to ensure the reproduction of plants within the whole population. Larvae of the two Epicephala species are competitive for resources; the population of E. mirivalvata is much smaller than that of E. lativalvaris, which has resulted from the differences in the female ovipositor structures and oviposition mode. The life history of Epicephala species highly coincides with the phenology of Breynia plants, and different phenology of B. fruticosa resulted in the different life history of the two Epicephala species in Hainan and Fujian. The natural hybridization of two host plants, possibly induced by the alternate pollination of two Epicephala species, is briefly discussed.  相似文献   

20.
Four allelic forms of serum plasminogen (PLG) were detected in baboons (Papio hamadryas Linneaus 1758) by isoelectric focusing and were determined to be inherited as autosomal codominant traits. Linkage analysis of data from 179 progeny and their parents revealed that PLG is tightly linked (lod score = 30.20) to the gene encoding apolipoprotein(a) (LPA), as in humans. No recombinant individuals were identified. This is the first linkage detected between PLG and LPA in any species other than humans and is the first genetic linkage identified in a nonhuman primate species by family studies.  相似文献   

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