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1.
The female reproductive structures and their development, and the vegetative structure are studied in 17 species of red algae in the Cryptonemiales (Rhodophyceae). Three genera, Weeksia, Constantinea, and the type species of Leptocladia, are removed from the Dumontiaceae to a newly created family, the Weeksiaceae, because of differing postfertilization events leading to the development of the gonimoblast from a cell of the carpogonial branch. Three genera of Dumontiaceae are studied: Pikea, including P. californica, the type species, and Pikea robusta a newly described species; Dilsea californica, and a newly described species of Neodilsea, a genus heretofore known only from the northwestern Pacific. Two transfers are made from the genus Leptocladia, 1 to Farlowia, as F. conferta, and 1 to Rhodophyllis (Gigartinales) as R. peruviana. Three species in the Kallymeniaceae are redescribed: Kallymenia pacifica, a rare and nearly unknown species from southern California and adjacent Pacific Mexico; K. norrisii from central California; and K. oblongifructa from Washington, Oregon, and northern California.  相似文献   

2.
Aims: To evaluate the diversity and antimicrobial activity of bacteria from the marine sponges Suberites carnosus and Leucosolenia sp. Methods and Results: Two hundred and thirty‐seven bacteria were isolated from the sponges S. carnosus (Demospongiae) and Leucosolenia sp. (Calcarea). Isolates from the phyla Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria were obtained. Isolates of the genus Pseudovibrio were dominant among the bacteria from S. carnosus, whereas Pseudoalteromonas and Vibrio were the dominant genera isolated from Leucosolenia sp. Approximately 50% of the isolates from S. carnosus displayed antibacterial activity, and c. 15% of the isolates from Leucosolenia sp. demonstrated activity against the test fungal strains. The antibacterial activity observed was mostly from Pseudovibrio and Spongiobacter isolates, while the majority of the antifungal activity was observed from the Pseudoalteromonas, Bacillus and Vibrio isolates. Conclusions: Both sponges possess a diverse range of bioactive and potentially novel bacteria. Differences observed from the sponge‐derived groups of isolates in terms of bioactivity suggest that S. carnosus isolates may be a better source of antibacterial compounds, while Leucosolenia sp. isolates appear to be a better source of antifungal compounds. Significance and Impact of the Study: This is the first study in which cultured bacterial isolates from the marine sponges S. carnosus and a Leucosolenia sp. have been evaluated for their antibacterial activity. The high percentage of antibacterial isolates from S. carnosus and of antifungal isolates from Leucosolenia sp. suggests that these two sponges may be good sources for potentially novel marine natural products.  相似文献   

3.
For the fermentative production of plant-specific flavanones (naringenin, pinocembrin) by Escherichia coli, a plasmid was constructed which carried an artificial biosynthetic gene cluster, including PAL encoding a phenylalanine ammonia-lyase from a yeast, ScCCL encoding a cinnamate/coumarate:CoA ligase from the actinomycete Streptomyces coelicolor A3(2), CHS encoding a chalcone synthase from a licorice plant and CHI encoding a chalcone isomerase from the Pueraria plant. The recombinant E. coli cells produced (2S)-naringenin from tyrosine and (2S)-pinocembrin from phenylalanine. When the two subunit genes of acetyl-CoA carboxylase from Corynebacterium glutamicum were expressed under the control of the T7 promoter and the ribosome-binding sequence in the recombinant E. coli cells, the flavanone yields were greatly increased, probably because enhanced expression of acetyl-CoA carboxylase increased a pool of malonyl-CoA that was available for flavanone synthesis. Under cultural conditions where E. coli at a cell density of 50 g/l was incubated in the presence of 3 mM tyrosine or phenylalanine, the yields of naringenin and pinocembrin reached about 60 mg/l. The fermentative production of flavanones in E. coli is the first step in the construction of a library of flavonoid compounds and un-natural flavonoids in bacteria.  相似文献   

4.
A. vaginal isolate of Neisseria has been reported to resemble Neisseria meningitidis in biochemical characteristics but to react with serological reagents that are specific to the PI porin from Neisseria gonorrhoeae. We have confirmed that this isolate has the biochemical attributes of a meningococcus and have shown that it clusters among meningococcal Isolates on a dendrogram based on isoenzyme variation within housekeeping enzymes from populations of N. meningitidis and N. gonorrhoeae. Furthermore, the sequences of the fbp and adk genes were typical of those of N. meningitidis and were distinct from those of N. gonorrhoeae. However, the porB gene was very similar to the por genes of N. gonorrhoeae isolates that express the PIB class of outer-membrane porin (differing from one gonococcal por allele at only a single nucleotide site), and was clearly distinct from the porB genes of N. meningitidis. The isolate therefore appears to be a typical meningococcus, except that its porB gene has been replaced with the por gene from a gonococcus.  相似文献   

5.
The new genus Melogonimus is defined and adults of its type-species, M. rhodanometra n. sp., are described from Rhina ancylostoma from Moreton Bay, Queensland. This is the first record of a digenean from this host species. It is argued that metacercariae from the portunid crab Portunus pelagicus from Hervey Bay, off Queensland, belong to M. rhodanometra. The definition of the family Ptychogonimidae is amended, and a key to its two genera is given. Melogonimus is characterised by a smooth genital atrium wall, a large sinus-organ, a large muscular seminal vesicle, a weakly developed pars prostatica, a pre-testicular uterus and confluent post-testicular vitelline fields.  相似文献   

6.
From extensive cytological, ecological, and morphological studies, it appears that cultivated rye (Secale cereale L.) originated from weedy products derived from introgression of S. montanum into S. vavilovii. Secale vavilovii appears to have been derived from S. silvestre as a consequence of chromosomal translocations. Secale silvestre was, in turn, derived from S. montanum or a common ancestor. Secale africanum, S. dalmaticum, S. ciliatoglume, and S. kuprijanovii appear to be only slightly modified isolated populations of S. montanum. Populations of S. anatolicum are weedy forms of S. montanum, genealogically and chromosomally distinct from the weedy annual forms from which S. cereale arose.  相似文献   

7.
Nine species of Stephanostomum are described from Australian and Southern Pacific marine fishes: Stephanostomum madhaviae n. sp. [syn. S. orientalis of Madhavi (1976)] from Caranx ignobilis, off Hope Island, Queensland, with 30-34 circum-oral spines and vitelline fields almost reaching to the posterior extremity of the cirrus-sac; S. bicoronatum (Stossich, 1883) from Argyrosomus hololepidotus, off Southport Broadwater, Queensland; S. votonimoli n. sp. from Scomberoides lysan, off Moorea, French Polynesia (type-locality) and Western Samoa, with 33-38 circum-oral spines, a uroproct and the vitelline fields not reaching the cirrus-sac; S. nyoomwa n. sp. from Caranx sexfasciatus, off Heron Island, Queensland, with 33-38 circum-oral spines, a uroproct and the vitelline fields reaching the cirrus-sac; S. cobia n. sp. from Rachycentron canadum, off Heron Island, with 36 circum-oral spines, a uroproct and the vitelline fields reaching the cirrus-sac; S. petimba Yamaguti, 1970 from Seriola hippos, off Rottnest Island, Western Australia; S. pacificum (Yamaguti, 1951) from Pseudocaranx wrighti, off Fremantle, Western Australia; S. aaravi n. sp. from Lethrinus miniatus, off Heron Island, with 36-39 circum-oral spines, probably a uroproct and the vitelline fields reaching the ventral sucker; S. pagrosomi (Yamaguti, 1939) from L. nebulosus, L. miniatus and L. atkinsoni off Heron Island, Pagrus auratus, off Rottnest Island, Western Australia and Gymnocranius audleyi, off Heron Island. A digest of described species of Stephanostomum is included as an appendix.  相似文献   

8.
Volatile chemicals from Citrus and Salix host plants evoke orientation behavior in males of the species Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae). These chemicals are emitted from wounded branches. We hypothesized that when released, these chemicals may indicate the presence of an individual to other conspecifics. Insects that originate from different host plants may use different plant chemicals from their own host to communicate with conspecifics. To further explore this theory, we investigated this communication system in a population of A. malasiaca from a third host plant, blueberry (Vaccinium spp.). Males from a blueberry host (Vaccinium population) were attracted to the odor of wounded Vaccinium branches when released near a female model in the laboratory, as has been observed in males found on Citrus and Salix host plants. The Vaccinium branch extract that was attractive to the males was separated into six fractions, of which two were active. Three active compounds were subsequently identified: β-caryophyllene and sulfur from the hexane fraction, and (E)-phytol in the weakly polar fraction. The latter two active compounds of Vaccinium branches were different from those found in Citrus and Salix.  相似文献   

9.
We present a study of the genetic variation, genetic structure, and outcrossing rate of two wild populations of Phaseolus coccineus ssp. formosus (both from Central Mexico), two cultivated populations of P. coccineus ssp. coccineus (one from Central Mexico, the other from Chiapas), and one cultivated population of P. vulgaris (from Central Mexico), using seven electrophorectic loci. All the populations of P. coccineus showed high and similar levels of genetic variation, without differences among wild and cultivated populations (H ranged between 0.187 to 0.271). In contrast, P. vulgaris has low levels of genetic variation (H = 0.041). The three P. coccineus populations from Central Mexico were genetically similar, while the cultivated P. coccineus from Chiapas and the cultivated P. vulgaris from Central Mexico were very different. In all the loci and all the populations for both species, the fixation indices (F) were positive and differed significantly from random mating expectation in 59% of the cases for P. coccineus. The highest F was the estimated for P. vulgaris. For P. coccineus, the multilocus outcrossing rate estimates ranged from 0.592 to 0.698, and these did not differ significantly among populations. For P. coccineus, we also estimated the outcrossing rate for each of 60 different families, showing great variation, with a majority of families with a t between 0.8 and 1, but a substantial fraction of the families with a t as low as 0.12–0.20. The domestication process has neither eroded the levels of genetic variation of the cultivated populations of P. coccineus nor changed its mating system.  相似文献   

10.
The polysaccharides from the envelopes of heterocysts of Cylindrospermum licheniforme Kütz., and of heterocysts and spores of Anabaena variabilis Kütz., like those from the differentiated cells of Anabaena cylindrica Lemm., have a 1,3-linked backbone consisting of glucosyl and mannosyl residues in a molar ratio of approximately 3:1. As is the case with A. cylindrica the polysaccharides from A. variabilis and from the heterocysts of C. licheniforme have terminal xylosyl and galactosyl residues as side branches. In addition, the polysaccharide from C. licheniforme resembles that from A. cylindrica in having terminal mannosyl residues as side branches (absent from A. variabilis). The polysaccharides from A. variabilis resemble that from A. cylindrica in having glucose-containing side branches (absent from the heterocyst polysaccharide from C. licheniforme), but in contrast to the polysaccharides from the other two species they also have terminal arabinosyl residues as side branches. All of the polysaccharides mentioned appear to be structurally related; we present tentative structures for those not previously investigated. In contrast, the envelope of spores of C. licheniforme contains only a largely 4-linked galactan. The bulk of this envelope is not polysaccharide in nature, and contains aromatic groups.  相似文献   

11.
12.
 In this study we construct a phylogenetic hypothesis for the relatedness among disjunct subspecies of Cyclamen repandum and its two allopatric congeners, C. creticum and C. balearicum in order to examine the evolutionary divergence of currently isolated populations across the western Mediterranean. The most parsimonious phylogenetic tree obtained from sequencing the cpDNA trnL (UAA) intron suggests a major phylogeographic divide in southern Greece between two clades. The first clade comprises samples of C. repandum subsp. peloponnesiacum (from the Peloponnese) and C. creticum (from Crete). The second comprises samples of C. repandum subsp. repandum (from Croatia, Italy, southern France, Corsica, Sardinia and Sicily), C. repandum subsp. rhodense (from Rhodes and Kos) and C. balearicum (from the Balearic Islands and southern France). These data suggest that C. creticum has evolved in allopatry from C. repandum subsp. peloponnesiacum and that C. balearicum and C. repandum ssp. rhodense have diverged from C. repandum subsp. repandum at its western and eastern distribution limits. At one small site on Corsica, a population of C. repandum may have introgressed with relictual populations of C. balearicum. These divergence patterns illustrate how a phylogenetic perspective can be used to better understand the evolution of endemism in the Mediterranean flora. Received February 19, 2001 Accepted August 22, 2001  相似文献   

13.
Numerous individuals of the poorly known species Lecithostaphylus retroflexus (Zoogonidae) and Tergestia acanthocephala (Fellodistomidae) have been recovered from the teleost fish Belone belone gracilis from off the Scandola Nature Reserve, Western Mediterranean. They are redescribed, incorporating previously undescribed features: for L. retroflexus, a post-oral ring, a bipartite seminal vesicle, the shape of the excretory vesicle, the subterminal excretory pore and the flask-shaped gland-cells associated with the distinctly pedunculate ventral sucker; and for T. acanthocephala, the intestinal bifurcation in the forebody, necessitating its return to the genus Tergestia from Theledera. Additionally, T. acanthocephala is compared with T. laticollis from various species of Trachurus from the same geographical area.  相似文献   

14.
Puccinia lagenophorae is a rust fungus originating from Australasia which has spread throughout the world. A phylogenetic analysis of taxa related to this species was performed using rDNA (LSU, ITS) sequence data. The analyses revealed a well-supported cluster including all specimens of P. lagenophorae. By evaluating morphological and sequence data, the species is taxonomically re-defined and a list of synonyms is provided. Puccinia distincta on Bellis perennis, a species recently separated from P. lagenophorae, P. saccardoi, a species on the Goodeniaceae, and P. byliana, a species so far only known from South Africa, are reduced to synonymy in P. lagenophorae, as are several other species. Our analysis indicates that P. lagenophorae is likely not derived from the northern hemisphere species P. obscura, but from a species from Australia host-alternating between Asteraceae (aecial host) and Cyperaceae/Juncaceae (telial host). Another related species, P. stylidii (on Stylidium sp., Stylidiaceae) may have been derived from the same parental species as P. lagenophorae. From ontogenetical and morphological studies, the presence of pycnia could not be confirmed in the life cycle of this species, and the width of the pedicel of teliospores at the point of attachment was found to be highly variable and not a taxonomic character. The number of known host species is approximately 150, including 41 new host plants recorded herein.  相似文献   

15.
Phylogenetic relationships between Nostoc cyanobionts in the lichen genus Pannaria were studied to evaluate their correlation to geography, habitat ecology, and other patterns previously reported. The 16S rRNA gene sequences of a total of 37 samples of 21 Pannaria species from seven countries from the Northern and Southern hemispheres were analyzed and compared with 69 free‐living and symbiotic cyanobacterial strains. The sequences from Pannaria were distributed throughout a branch of Nostoc sequences previously called “the Nephroma guild,” and within two subgroups from another branch, referred to as the “Peltigera guild,” although there was a gradual transition between the two major groups. There is a more diverse pattern of relationships between Nostoc sequences from bipartite versus tripartite lichen species in Pannaria, compared with other well‐studied genera, such as Nephroma and Peltigera. Cyanobionts from several tripartite Pannaria species from the Southern Hemisphere and corticolous bipartite species from both hemispheres were grouped together. Four sequences of Pannaria and Pseudocyphellaria cyanobionts from rocks in the Chilean Juan Fernández Islands were nested within corticolous cyanobionts, whereas the terricolous “Pannaria sphinctrina clade” was placed with other terricolous strains. The cluster patterns derived from phylogenetic analysis were partly reflecting lichen taxonomy, in two groups of lichen species, possibly indicating coevolution. The phylogram partly also reflected lichen ecology. Three Pannaria species have very different cyanobiont strains when they grow in different habitats.  相似文献   

16.
Numerous trehalose synthases (TreS) from thermophilic microorganisms have extra C-terminal domains. To determine the function of the N- and C-terminal domains of TreS from the thermophilic bacterium Meiothermus ruber CBS-01, the two domains were expressed. From the findings, the N-terminal domain from M. ruber was not active when compared with that from Thermus thermophilus, which had been studied previously. The circular dichroism spectrum showed that the secondary structure of N-terminal domain from M. ruber underwent a greater change than that of C terminus. In addition, the N-terminal domain from T. thermophilus and C terminus from M. ruber were fused. The fusion protein TSTtMr was more efficient and thermostable than the TreS from M. ruber. The N-terminal domain from M. ruber and C terminus from T. thermophilus were fused. The optimum temperature and thermostability of fusion protein TSMrTt were similar to the TreS from M. ruber. It was presumed that aside from the C-terminal domain, the N-terminal domain of TreS from thermophilic bacteria could influence thermostability. For the TreS from M. ruber, the mutant protein R392F led to a complete loss in activity, and R392A showed a sharp decrease in activity.  相似文献   

17.
Adenosine kinase (adk) from the moss Physcomitrella patens (Hedw.) B.S.G. was cloned from a cDNA library by functional complementation of an Escherichia coli purine auxotrophic strain. The length of the entire cDNA clone was 1175 bp with an open reading frame coding for a protein with a predicted molecular weight of 37.3 kDa. Southern analysis indicated the presence of a single adenosine kinase gene within the Physcomitrella genome. The deduced amino acid sequence had a 52% identity with the human adenosine kinase. The transfer of phosphate from ATP to adenosine resulting in AMP, as well as the phosphorylation of the cytokinin, isopentenyladenosine, to isopentenyladenosine monophosphate, was shown by in vitro enzyme assays using crude extracts from E. coli mutants expressing the adk cDNA clone and from Physcomitrella chloronemal tissue. Results from in vivo feeding of chloronemal tissue with tritiated isopentenyladenosine suggest that adenosine kinase plays an important role in the conversion of cytokinins towards their nucleotides in Physcomitrella.  相似文献   

18.
We report successful overwintering of Diadromus pulchellus in North America (Ontario) following introduction of this species from Europe to control the leek moth, Acrolepiopsis assectella, a recently established alien species. Field rearing revealed that the native Diadromus subtilicornis emerged only from diamondback moth, Plutella xylostella, whereas D. pulchellus was reared almost exclusively from leek moth. The single D. pulchellus reared from diamondback moth was anticipated because host range studies found this species could develop on both leek moth and diamondback moth in the laboratory, although, it had not been previously reported from diamondback moth in the field in Europe. DNA barcoding of specimens of both Diadromus spp. confirmed their species status and novel morphological characters are presented to distinguish D. pulchellus from D. subtilicornis. In addition, DNA from specimens of D. subtilicornis from Europe clustered with DNA from specimens across Canada, confirming that it is a single Holarctic species. Finally, a new host association for D. subtilicornis is recorded from the dame's rocket moth: Pseudoplutella porrectella.  相似文献   

19.
We investigated the association between a gall midge, Illiciomyia yukawai, and its symbiotic fungi on Japanese star anise, Illicium anisatum. The number of fungal species isolated from the galls increased with development of the galls, whereas those from the leaves showed a different trend. Botryosphaeria dothidea was dominant in the galls from June to October, and after that Phomopsis sp. 1, Colletotrichum sp., and Pestalotiopsis sp. became dominant. Although B. dothidea was not isolated from the leaves, it was detected from mycangia (abdominal sternite VII) of egg-laying adults at a high isolation frequency (>90%). However, B. dothidea was not isolated from mycangia of adults emerging from galls that were enclosed by plastic bags. This indicates that I. yukawai is closely associated with B. dothidea and that its newly emerged adults do not take the fungus into mycangia directly from the galls where they had developed. Also, the fungus from the fungal layers of ambrosia galls has less ability to propagate on artificial media despite the presence of its mycelial mass in mature galls.  相似文献   

20.
Skrjabinelazia Sypliaxov, 1930 comprises 10 species distinguished by several characters typical of the genus including, among the most important, the presence/absence of spicules, cuticle ornamentation and vesicles, head-shape, the presence/absence of a leaflet crown in the buccal cavity, female tail-shape and male cone-shape. The three samples studied are new species: S. boomkeri n. sp., a parasite of Pachydactylus turneri, Gekkonidae, from South Africa (Klaserie Reserve); S. vozae n. sp., a parasite of Lacerta vivipara, Lacertidae, from France (Cévennes), which is close to two lacertid parasites, S. taurica Sypliaxov, 1930 and L. hoffmanni Li, 1934, respectively from the Crimea and North China (Peking); and S. mawsangelae n. sp. (male unknown), a parasite of Christinus marmoratus, Gekkonidae, from Australia (Pearson Island), which is, surprisingly, distinct from Skrjabinelazia sp. of Angel & Mawson (1968) from the same host in another region (North of Adelaide) of South Australia. Two main groups are distinguished in Skrjabinelazia: the species with spicules which are parasitic in the Lacertidae, and the species with a gubernaculum only which are parasitic in the Gekkonidae. The unique species described from the Iguanidae, S. intermedia (Freitas, 1940) from Brazil (Para), also without spicules, seems to be derived from gekkonid parasites, as it also has an evolved oesophagus with a glandular region, unlike the simple oesophagus seen in the larval stages of Skrjabinelazia.  相似文献   

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