Disinfection of striped trumpeter (Latris lineata) eggs with glutaraldehyde     

D.T. Morehead  P.R. Hart 《Aquaculture International》2003,11(3):255-260

This study assessed the effect of immersing striped trumpeter eggs in 0 (control), 200, 400, 800, 1600 or 3200 ppm glutaraldehyde for 10 minutes, two days before hatching. High concentrations of glutaraldehyde (1600 and 3200 ppm) resulted in no eggs hatching and only 1% of eggs hatched after treatment with 800 ppm glutaraldehyde. Hatching success of eggs treated with 0, 200 or 400 ppm glutaraldehyde did not differ (77 ± 6%, n = 3). However, only 2% of larvae from the control treatment survived to day 5 post-hatching, compared to 45 and 69%, respectively of the larvae from the 200 and 400 ppm glutaraldehyde treatment. By day 9 post-hatching, larvae from the 400 ppm glutaraldehyde treatment had significantly higher survival (59%) than larvae from the 200 ppm glutaraldehyde treatment (28%). Thiosulphate citrate bile salt sucrose agar (TCBS) medium confirmed the presence of bacteria within the seawater medium, on all control eggs and on 83% of eggs disinfected with 200 ppm glutaraldehyde, but no bacterial colonies formed on eggs treated with 400, 800, 1600 or 3200 ppm glutaraldehyde. This study found highest survival of striped trumpeter larvae from eggs disinfected with 400 ppm glutaraldehyde and suggests that increased survival was a result of reduced bacterial loading.  相似文献   

Intraspecific food competition in fishes   总被引：3，自引：0，他引：3  

Ashley J. W. Ward  Michael M. Webster  & Paul J. B. Hart 《Fish and Fisheries》2006,7(4):231-261

Intraspecific food competition exerts powerful selective forces on all animals; successful foragers thrive relative to weaker conspecifics. Understanding competition is therefore fundamental both to ecological insight and to conservation efforts. Fish are adaptable and tractable experimental organisms, offering excellent model systems for studies on competition, and they lend themselves to two approaches: (i) studies of short‐term competition, which quantify the components of behavioural interactions; (ii) studies of long‐term interactions, in which the indeterminate nature of fish growth makes it possible to measure rates directly and correlate them with competitive success. The nature and the intensity of competition vary according to resource characteristics and distributions in time and space, the ecological context, and the relative competitive abilities of the foragers. Second‐order effects, such as winner and loser consequences, add to the complexity and frustrated early attempts to develop realistic models of intraspecific competition. Recently, however, considerable advances have been made in both laboratory and field studies on fishes adding to our understanding of these interacting effects. At the same time, the application of individual‐based modelling offers the prospect of progress towards greater realism and accuracy in predicting competitive outcomes. This review draws together a wide and disparate literature on intraspecific competition in fishes to facilitate the work of both empiricists and theoreticians towards these important goals. In the short term, competing individuals may adopt different behavioural strategies and feeding patterns or establish dominance hierarchies and feeding territories. In the longer term, competition can drive character displacement and the formation of species pairs and fish provide some of the most compelling examples of these processes in evolutionary biology. The challenge for the future is to further develop our understanding of the relationship between the competitive environment and the responses of fishes, particularly with closer co‐operation between empiricists and theoreticians, and to apply this knowledge to aquaculture and to better management of exploited fish stocks.  相似文献   

Molecular characterization of the fish-pathogenic fungus Aphanomyces invadans     

Lilley JH  Hart D  Panyawachira V  Kanchanakhan S  Chinabut S  Söderhäll K  Cerenius L 《Journal of fish diseases》2003,26(5):263-275

Aphanomyces invadans (Saprolegniaceae) is a peronosporomycete fungus associated with the serious fish disease, epizootic ulcerative syndrome (EUS), also known as mycotic granulomatosis. In this study, interspecific relationships were examined between A. invadans isolates and other aquatic animal pathogenic Saprolegniaceae, and saprophytic Saprolegniaceae from EUS-affected areas. Restriction fragment length polymorphisms and sequences of ribosomal DNA confirmed that A. invadans is distinct from all other species studied. A sequence from the internal transcribed spacer region ITS1, unique to A. invadans, was used to design primers for a PCR-based diagnostic test. Intraspecific relationships were also examined by random amplification of polymorphic DNA using 20 isolates of A. invadans from six countries. The isolates showed a high degree of genetic homogeneity using 14 random ten-mer primers. This provides evidence that the fungus has spread across Asia in one relatively rapid episode, which is consistent with reports of outbreaks of EUS. Physiological distinctions between A. invadans and other Aphanomyces species based on a data set of 16 growth parameters showed remarkable taxonomic congruence with the molecular phylogeny.  相似文献   

Fishery Science: The Unique Contributions of Early Life Stages     

Paul J. B. Hart 《Fish and Fisheries》2003,4(4):377-378

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Effect of temperature on hatching success and size of striped trumpeter (Latris lineata) larvae     

D. T. Morehead  P. R. Hart 《Aquaculture (Amsterdam, Netherlands)》2003,220(1-4):595-606

Egg samples were collected from captive striped trumpeter maintained under phase-shifted and simulated ambient photothermal regimes and incubated at 9, 10, 11, 12, 13, 14, 15 or 16 °C. No eggs hatched at 9 °C. Time to hatch decreased from 9.6 to 4.2 days as temperature increased from 10 to 16 °C. Survival to hatch was low at 10 and 11 °C, but similar within the range 12–16 °C. Larval length at hatching was greatest at 14 °C, with no significant difference in yolk volume or muscle depth at vent across the range of temperatures. The results of our study suggest that the optimal temperature for the incubation of striped trumpeter eggs is 14 °C, which is higher than found previously.  相似文献   

C and N availability affects the ¹⁵N natural abundance of the soil microbial biomass across a cattle manure gradient     

P. Dijkstra  O. V. Menyailo  R. R. Doucett  S. C. Hart  E. Schwartz  & B. A. Hungate 《European Journal of Soil Science》2006,57(4):468-475

The availability of C and N to the soil microbial biomass is an important determinant of the rates of soil N transformations. Here, we present evidence that changes in C and N availability affect the ¹⁵N natural abundance of the microbial biomass relative to other soil N pools. We analysed the ¹⁵N natural abundance signature of the chloroform‐labile, extractable, NO₃^–, NH₄⁺ and soil total N pools across a cattle manure gradient associated with a water reservoir in semiarid, high‐desert grassland. High levels of C and N in soil total, extractable, NO₃^–, NH₄⁺ and chloroform‐labile fractions were found close to the reservoir. The δ¹⁵N value of chloroform‐labile N was similar to that of extractable (organic + inorganic) N and NO₃^– at greater C availability close to the reservoir, but was ¹⁵N‐enriched relative to these N‐pools at lesser C availability farther away. Possible mechanisms for this variable ¹⁵N‐enrichment include isotope fractionation during N assimilation and dissimilation, and changes in substrate use from a less to a more ¹⁵N‐enriched substrate with decreasing C availability.  相似文献   

Interactions Between Sediments and Water Summary of the 7th International Symposium     

Evans  R. D.  Provini  A.  Mattice  J.  Hart  B.  Wisniewski  J. 《Water, air, and soil pollution》1997,99(1-4):1-7

The interactions between sediments and water have received increased emphasis over the last two decades, leading to a greater understanding of physical, chemical and biological processes in a wide range of aquatic systems including river, lake, estuarine and coastal systems. This new understanding has fostered research and assessment projects, and focused awareness on the implications of sediment/water interactions for policy and regulation. The international symposium on “The Interactions Between Sediments and Water” held in Baveno, Italy from 22–26 September 1996 was the seventh in a series of symposia held since 1976. All focused on issues relating to processes which occur near the sediment/water interface as well as responses to interactions between sediments and water. Previous symposia were held in Amsterdam in 1976, Kingston (Canada) in 1982, Geneva in 1984, Melbourne in 1986, Uppsala in 1990 and Santa Barbara in 1993. Almost 200 oral and poster presentations were made by attendees representing 27 nations, including dozens of participants from developing countries. The scientific sessions were organized around the following themes: sediment/water dynamics, contaminant interactions, sediment/nutrient relationships, sediments as historical records of deposition, sediment/water science in remote areas, sediment/organism interactions, and novel methods and analytical quality control. This paper attempts to summarize the key highlights of the various sessions.  相似文献   

Two classes of PDGF receptor recognize different isoforms of PDGF   总被引：75，自引：0，他引：75  

C E Hart  J W Forstrom  J D Kelly  R A Seifert  R A Smith  R Ross  M J Murray  D F Bowen-Pope 《Science (New York, N.Y.)》1988,240(4858):1529-1531

Previous studies involving platelet-derived growth factor (PDGF) have been based on the premise that a single cell-surface receptor binds all three isoforms of PDGF (AA, BB, and AB). It is now shown that two populations of PDGF receptor exist and can be distinguished by their ligand binding specificity. The B receptor binds only the BB dimer, whereas the A/B receptor binds AA, BB, and AB dimers. Human dermal fibroblasts appear to express seven times as much B receptor as A/B receptor. The B receptor is responsible for most PDGF receptor phosphorylation.  相似文献   

Energy extraction and use in a nomadic pastoral ecosystem     

Coughenour MB  Ellis JE  Swift DM  Coppock DL  Galvin K  McCabe JT  Hart TC 《Science (New York, N.Y.)》1985,230(4726):619-625

An analysis of annual energy flows in an arid tropical ecosystem inhabited by nomadic pastoralists provides insight into a subsistence life-style that has persisted in droughted environments for hundreds to thousands of years. Although a large fraction of the total energy consumed by the Ngisonyoka of Kenya followed a single pathway from plant to animal to human, they also harvested solar energy from a relatively diverse assemblage of energy flow channels. Energy utilization and conversion efficiencies were generally low, as the system is maintenance-rather than production-oriented. Energy flow to maintenance must be relatively high to support biotic responses that enable tolerance of abiotic variability and to stabilize energy flow under the stress of severe droughts. Energy utilization by the Ngisonyoka is therefore consistent with ecological patterns that promote rather than diminish ecological stability under stress.  相似文献   

THE EFFECT OF 1,2,5,6-DIBENZANTHRACENE ON THE GROWTH AND RESPIRATION OF YEAST     

Cook ES  Hart MJ  Joly RA 《Science (New York, N.Y.)》1938,87(2258):331-332

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