987 resultados para Species-recognition
Resumo:
There is a widely held paradigm that mangroves are critical for sustaining production in coastal fisheries through their role as important nursery areas for fisheries species. This paradigm frequently forms the basis for important management decisions on habitat conservation and restoration of mangroves and other coastal wetlands. This paper reviews the current status of the paradigm and synthesises the information on the processes underlying these potential links. In the past, the paradigm has been supported by studies identifying correlations between the areal and linear extent of mangroves and fisheries catch. This paper goes beyond the correlative approach to develop a new framework on which future evaluations can be based. First, the review identifies what type of marine animals are using mangroves and at what life stages. These species can be categorised as estuarine residents, marine-estuarine species and marine stragglers. The marine-estuarine category includes many commercial species that use mangrove habitats as nurseries. The second stage is to determine why these species are using mangroves as nurseries. The three main proposals are that mangroves provide a refuge from predators, high levels of nutrients and shelter from physical disturbances. The recognition of the important attributes of mangrove nurseries then allows an evaluation of how changes in mangroves will affect the associated fauna. Surprisingly few studies have addressed this question. Consequently, it is difficult to predict how changes in any of these mangrove attributes would affect the faunal communities within them and, ultimately, influence the fisheries associated with them. From the information available, it seems likely that reductions in mangrove habitat complexity would reduce the biodiversity and abundance of the associated fauna, and these changes have the potential to cause cascading effects at higher trophic levels with possible consequences for fisheries. Finally, there is a discussion of the data that are currently available on mangrove distribution and fisheries catch, the limitations of these data and how best to use the data to understand mangrove-fisheries links and, ultimately, to optimise habitat and fisheries management. Examples are drawn from two relatively data-rich regions, Moreton Bay (Australia) and Western Peninsular Malaysia, to illustrate the data needs and research requirements for investigating the mangrove-fisheries paradigm. Having reliable and accurate data at appropriate spatial and temporal scales is crucial for mangrove-fisheries investigations. Recommendations are made for improvements to data collection methods that would meet these important criteria. This review provides a framework on which to base future investigations of mangrove-fisheries links, based on an understanding of the underlying processes and the need for rigorous data collection. Without this information, the understanding of the relationship between mangroves and fisheries will remain limited. Future investigations of mangrove-fisheries links must take this into account in order to have a good ecological basis and to provide better information and understanding to both fisheries and conservation managers.
Resumo:
Carbon monoxide, the chief killer in fires, and other species are modelled for a series of enclosure fires. The conditions emulate building fires where CO is formed in the rich, turbulent, nonpremixed flame and is transported frozen to lean mixtures by the ceiling jet which is cooled by radiation and dilution. Conditional moment closure modelling is used and computational domain minimisation criteria are developed which reduce the computational cost of this method. The predictions give good agreement for CO and other species in the lean, quenched-gas stream, holding promise that this method may provide a practical means of modelling real, three-dimensional fire situations. (c) 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
Resumo:
Objective: To investigate: 1) the impact of clinical varicocele on reactive oxygen species (ROS) levels in neat and washed semen in a proven fertile population; and 2) the correlation between ROS levels, testicular volume, and varicocele grade in the same population of fertile men. Design: Prospective controlled clinical study. Setting: Andrology laboratory at tertiary-care hospital. Patient(s): One hundred fourteen healthy fertile men (81 normal fertile and 33 fertile with clinical varicocele) and 30 infertile patients (control subjects). Intervention(s): Standard semen analysis and measurement of sperm ROS production. Main Outcome Measure(s): Seminal parameters, seminal ROS levels, seminal leukocyte levels, clinical varicocele, and testis size. Result(s): Thirty-three of the 11.4 (29%) fertile men had clinical varicocele (grade 1, n = 14; grade 2, n = 11; and grade 3, n = 8), and the remaining 81 (71%) had a normal physical examination. Levels of ROS and semen quality did not differ significantly between the fertile men with or without varicocele. No significant differences in ROS levels in neat and washed semen were observed compared with fertile men with grades 2 and 3 varicocele and with fertile men with varicocele grade 1. The ROS levels in neat and washed semen were not significantly correlated with varicocele grade in fertile men. No significant correlations between ROS levels and testis volume were observed between the fertile groups. Conclusion(s): The presence of clinical varicocele in fertile men is not associated with higher seminal ROS levels or abnormal semen parameters. Levels of ROS are not correlated with varicocele grade or testis volume in the same population of fertile men.
Resumo:
The genera Lobatocreadium, Pseudocreadium, Hypocreadium and Dermadena are redefined and host lists given. Provisional keys to species of Lobatocreadium, Hypocreadium and Dermadena are presented. The following species are described from (1) the Great Barrier Reef: Lobatocreadium exiguum from Balistapus undulatus and Sufflamen bursa; Hypocreadium cavum n. sp. from Abalistes stellatus (type-host) and Cantheschenia grandisquamis; H. grandisquamis n. sp. from Cantheschenia grandisquamis; Dermadena spatiosa n. sp, from Cantheschenia grandisquamis; and (2) southwestern Australia: D. stirlingi n. sp. from Meeschenia hippocrepis. The following new combinations are made: Lobatocreadium vitellosum (Ozaki, 1936) n. comb. (originally Leptocreadium); Hypocrendium balistes (Nagaty, 1942) n. comb. (originally Pseudocreadium); H. biminensis (Sogandares-Bernal, 1959) n. comb. (originally Pseudocreadium); H. indicum (Madhavi, 1972) n. comb. (originally Pseudocreadium); and H. galapagoensis (Manter, 1945) n. comb. (originally Pseudocreadium). Several nominal species of Pseudocreadium and Hypocreadium are considered incertae sedis.
Resumo:
Previous work examining context effects in children has been limited to semantic context. The current research examined the effects of grammatical priming of word-naming in fourth-grade children. In Experiment 1, children named both inflected and uninflected noun and verb target words faster when they were preceded by grammatically constraining primes than when they were preceded by neutral primes. Experiment 1 used a long stimulus onset asynchrony (SOA) interval of 750 msec. Experiment 2 replicated the grammatical priming effect at two SOA intervals (400 msec and 700 msec), suggesting that the grammatical priming effect does not reflect the operation of any gross strategic effects directly attributable to the long SOA interval employed in Experiment 1. Grammatical context appears to facilitate target word naming by constraining target word class. Further work is required to elucidate the loci of this effect.
Resumo:
Analysis of the 16S rDNA sequence of Conglomeromonas largomobilis subsp. largomobilis supports a phylogenetic relationship with the species of the genus Azospirillum. This confirms results of previous nucleic acid hybridization studies (FALK, E. C., J. L. JOHNSON, V. D. L. BALDANI, J. DOBEREINER, and N. R. KRIEG. 1986. Int. J. Syst. Bacteriol. 36: 80-85). Conglomeromonas largomobilis subsp. largomobilis was most closely related to the species Azospirillim lipoferum and Azospirillum brasilense but sufficiently distant to warrant separate species status. Conglomeromonas largomobilis subsp. parooensis was more distantly related to the existing species of Azospirillum and represents an isolated subline of descent. On the basis of the phylogenetic evidence a prosposal is made to transfer the subspecies Conglom-eromonas largomobilis subsp. largomobilis to the genus Azospirillum as Azospirillum largomobile comb. nov. and to retain the genus Conglomeromonas by elevating the subspecies C. largomobilis subsp. parooensis to the type species of Conglomeromonas as Conglomeromonas parooensis sp. nov.
Resumo:
The phylogenetic relationships among the species of the genus Pedomicrobium were studied by comparing their 16S rRNA sequences, The Pedomicrobium species form a coherent phylogenetic cluster within the genera of the hyphal budding bacteria in the alpha-Proteobacteria. The sequences of two strains of Pedomicrobium australicum were obtained from DNAs extracted from nonviable freeze-dried cells, which are the only source of material available, and were found to be almost identical (level of similarity, 99.9%), Overall, the Pedomicrobium species are closely related, with sequence similarities ranging from 96.2 to 99.9%, Pedomicrobium manganicum is phylogenetically the most distantly related species and exhibits the lowest similarity (96.2%) with Pedomicrobium americanum, Australian isolate Pedomicrobium sp, strain ACM 3067, P, americanum, and P, australicum are all very highly related, with similarities greater than 99%, Pedomicrobium sp, strain ACM 3067 is most closely related to P, australicum (level of similarity, 99.6%) and P, americanum (99.4%), These manganese-oxidizing species are more closely related to the iron-oxidizing species Pedomicrobium ferrugineum than to the other manganese-oxidizing species, P, manganicum. Taxonomic uncertainties resulting from the loss of the type culture of P, australicum are discussed.
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Six Burkholderia solanacearum (formerly Pseudomonas solanacearum) genomic DNA fragments were isolated, using RAPD techniques and cloning, from the three genetically diverse strains: ACH092 (Biovar 4), ACH0158 (Biovar 2) and ACH0171 (Biovar 3) (1). One of these cloned fragments was selected because it was present constantly in all bacterial strains analysed. The remaining five clones were selected because Southern hybridisation revealed that each showed partial or complete specificity towards the strain of origin. A seventh genomic fragment showing a strain-specific distribution in Southern hybridisations was obtained by differential restriction, hybridisation and cloning of genomic DNA. Each of these clones was sequenced and primers to amplify the insert were designed. When DNA from the strain of origin was used as template, PCR amplification for each of these fragments yielded a single band on gel analysis. One pair of primers amplified the species-constant fragment of 281 bp from DNA of all B. solanacearum strains investigated, from DNA of the closely related bacterium which causes ''blood disease'' of banana (BDB) and in P. syzigii. The sensitivity of detection of B. solanacearum using these ubiquitous primers was between 1.3 and 20 bacterial cells. The feasibility and reliability of a PCR approach to detection and identification of B. solanacearum was tested in diverse strains of the bacterium in several countries and laboratories.
Resumo:
The fatty acid composition of 11 species of fish caught off the northeast coast of Australia was determined. No fatty acid profiles have been previously published for fish from this area nor for nine of these species. Although the percentage of polyunsaturated fatty acid (PU FA) was the same as the calculated average for Australian fish (42.3%), the percentage of n-3 fatty acids was lower (24.4 +/- 5.4% vs. 30.7 +/- 10.1%) and the n-6 fatty acids higher (16.5 +/- 4.5% vs. 11.2 +/- 5.9%), P < 0.001 in each case. The major n-3 PUFA were docosahexaenoic (15.6 +/- 6.3%) and eicosapentaenoic acid (4.3 +/- 1.1%) while the major n-6 PUFA were arachidonic (8.3 +/- 3.2%) and n-6 docosatetraenoic acid (3.1 +/- 1.3%). The second-most abundant class of fatty acid was the saturates (31.6 +/- 3.5%) while the monounsaturates accounted for 17.4 +/- 4.3% of the total fatty acids. The monounsaturate with the highest concentration was octadecenoic acid (11.8 +/- 2.6%). There was a positive correlation between the total lipid content and saturated and monounsaturated fatty acids (r = 0.675 and 0.567, respectively) and a negative correlation between the total lipid content and PUFA(r = 0.774).
Resumo:
The following lepocreadiid species are described from Cheilodactylidae from south-western Australia. Cliveus peroni n. g., n. sp, from Nemadactylus valenciennesi is characterised by its attenuated forebody and C. acaenodera n. sp. from Dactylophora nigricans by its attenuated forebody, the pattern of forebody spination and the large cirrus-sac. Jericho chojeri n. g., n. sp. from N. valenciennesi has a large infundibuliform oral sucker and paired ani. Rugocavum n. g. is distinguished by the possession of a blind, wrinkled glandular pit on the postero-ventral surface of the forebody. R. nemadactyli n. sp. from N. valenciennesi has its vitelline field restricted to the hindbody, whereas in R. morwong n. sp, from N. valenciennesi the vitelline field reaches into the forebody. Paraneocreadium australiense Kruse, 1978 from N. valenciennesi is redescribed and its coiled internal seminal vesicle and lobed gonads are considered distinctive features. Scaphatrema nemadactyli (Kurochkin & Korotaeva, 1972) n. g., n. comb. from N. valenciennesi has a wrinkled, boat-shaped body, a 'Lepidapedon-like' cirrus-sac and multiple testes; it was originally placed in the genus Multitestis, but these characters suggest that a new genus should be erected for it within the subfamily Lepidapedinae.
Resumo:
The tannin-degrading species Streptococcus gallolyticus and Streptococcus caprinus have been shown to be subjective synonyms on the basis of their levels of 16S rRNA sequence similarity (98.3%) and DNA-DNA homology (>70%) and the phenotypes of their type strains. S. gallolyticus has nomenclatural priority according to Rule 24b(2) of the International Code of Nomenclature of Bacteria.
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We previously generated a panel of T helper cell 1 (Th1) clones specific for an encephalitogenic peptide of myelin proteolipid protein (PLP) peptide 139-151 (HSLGKWLGHPDKF) that induces experimental autoimmune encephalomyelitis (EAE) upon adoptive transfer. In spite of the differences in their T cell receptor (TCR) gene usage, all these Th1 clones required W144 as the primary and most critical TCR contact residue for the activation. In this study, we determined the TCR contact residues of a panel of Th2/Th0 clones specific for the PLP peptide 139-151 generated either by immunization with the PLP 139-151 peptide with anti-B7-1 antibody or by immunization with an altered peptide Q144. Using alanine-substituted peptide analogues of the native PLP peptide, we show that the Th2 clones have shifted their primary contact residue to the NH2-terminal end of the peptide. These Th2 cells do not show any dependence on the W144, but show a critical requirement for L141/G142 as their major TCR contact residue. Thus, in contrast with the Th1 clones that did not proliferate to A144-substituted peptide, the Th2 clones tolerated a substitution at position 144 and proliferated to A144 peptide. This alternative A144 reactive repertoire appears to have a critical role in the regulation of autoimmune response to PLP 139-151 because preimmunization with A144 to expand the L141/G142-reactive repertoire protects mice from developing EAE induced with the native PLP 139-151 peptide. These data suggest that a balance between two different T cell repertoires specific for same autoantigenic epitope can determine disease phenotype, i.e., resistance or susceptibility to an autoimmune disease.
Resumo:
The aims of this study were to characterize the recently cloned rat norepinephrine transporter (NET) in more detail and in particular to study possible species differences in its pharmacological properties compared with the human and bovine NETs. The study was carried out by measuring the uptake of [3H]norepinephrine in COS-7 cells expressing the NET after transient transfection with rat, human, or bovine NET cDNA. There were small but significant differences between the rat NET and the human or bovine NETs with respect to the affinities of sodium ions (greater for rat than for bovine) of the substrates norepinephrine, epinephrine, and 1-methyl-4-phenylpyridinium (greater for human than for rat), and of the inhibitor cocaine (greater for human and bovine than for rat), whereas the affinities of dopamine and of most inhibitors, including tricyclic antidepressants, showed no species differences. The fact that the affinities for some substrates, cocaine and sodium ions exhibited small but significant interspecies differences among the rat, human, and bovine NETs suggests that ligand recognition, the translocation process, and sodium ion dependence are influenced differentially by just a few amino acid exchanges in the primary sequences of the transporters. On the other hand, the lack of any major differences in the pharmacological properties of the rat, human, and bovine NETs in this study suggests that data obtained in previous studies on rat tissues and bovine cells can be extrapolated, in all except the most quantitative analyses, to the properties of the human NET.