998 resultados para Nutritional Ecology


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Traditional measures of termite food preference assess consequences of foraging behavior such as wood consumption, aggregation and/or termite survivorship. Although studies have been done to investigate the specifics of foraging behavior this is not generally integrated into choice assay experiments. Here choice assays were conducted with small isolated (orphaned) groups of workers and compared with choice assays involving foragers from whole nests (non-orphaned) in the laboratory. Aggregation to two different wood types was used as a measure of preference. Specific worker caste and instars participating in initial exploration were compared between assay methods, with samples of termites taken from nest carton material and sites where termites were feeding. Aggregation results differ between choice assay techniques. Castes and instars responsible for initial exploration, as determined in whole nest trials, were not commonly found exploring in isolated group trials, nor were they numerous in termites taken from active feeding sites. Consequently the use of small groups of M. turneri worker termites extracted from active feeding sites may not be appropriate for use in choice assays.

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Unlike exercising mammals, migratory birds fuel very high intensity exercise (e.g., flight) with fatty acids delivered from the adipose tissue to the working muscles by the circulatory system. Given the primary importance of fatty acids for fueling intense exercise, we discuss the likely limiting steps in lipid transport and oxidation for exercising birds and the ecological factors that affect the quality and quantity of fat stored in wild birds. Most stored lipids in migratory birds are comprised of three fatty acids (16:0, 18:1 and 18:2) even though migratory birds have diverse food habits. Diet selection and selective metabolism of lipids play important roles in determining the fatty acid composition of birds which, in turn, affects energetic performance during intense exercise. As such, migratory birds offer an intriguing model for studying the implications of lipid metabolism and obesity on exercise performance. We conclude with a discussion of the energetic costs of migratory flight and stopover in birds, and its implications for bird migration strategies.

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The studies presented in this thesis contribute to the understanding of evolutionary ecology of three major viruses threatening cultivated sweetpotato (Ipomoea batatas Lam) in East Africa: Sweet potato feathery mottle virus (SPFMV; genus Potyvirus; Potyviridae), Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus; Closteroviridae) and Sweet potato mild mottle virus (SPMMV; genus Ipomovirus; Potyviridae). The viruses were serologically detected and the positive results confirmed by RT-PCR and sequencing. SPFMV was detected in 24 wild plant species of family Convolvulacea (genera Ipomoea, Lepistemon and Hewittia), of which 19 species were new natural hosts for SPFMV. SPMMV and SPCSV were detected in wild plants belonging to 21 and 12 species (genera Ipomoea, Lepistemon and Hewittia), respectively, all of which were previously unknown to be natural hosts of these viruses. SPFMV was the most abundant virus being detected in 17% of the plants, while SPMMV and SPCSV were detected in 9.8% and 5.4% of the assessed plants, respectively. Wild plants in Uganda were infected with the East African (EA), common (C), and the ordinary (O) strains, or co-infected with the EA and the C strain of SPFMV. The viruses and virus-like diseases were more frequent in the eastern agro-ecological zone than the western and central zones, which contrasted with known incidences of these viruses in sweetpotato crops, except for northern zone where incidences were lowest in wild plants as in sweetpotato. The NIb/CP junction in SPMMV was determined experimentally which facilitated CP-based phylogenetic and evolutionary analyses of SPMMV. Isolates of all the three viruses from wild plants were genetically similar to those found in cultivated sweetpotatoes in East Africa. There was no evidence of host-driven population genetic structures suggesting frequent transmission of these viruses between their wild and cultivated hosts. The p22 RNA silencing suppressor-encoding sequence was absent in a few SPCSV isolates, but regardless of this, SPCSV isolates incited sweet potato virus disease (SPVD) in sweetpotato plants co-infected with SPFMV, indicating that p22 is redundant for synergism between SCSV and SPFMV. Molecular evolutionary analysis revealed that isolates of strain EA of SPFMV that is largely restricted geographically in East Africa experience frequent recombination in comparison to isolates of strain C that is globally distributed. Moreover, non-homologous recombination events between strains EA and C were rare, despite frequent co-infections of these strains in wild plants, suggesting purifying selection against non-homologous recombinants between these strains or that such recombinants are mostly not infectious. Recombination was detected also in the 5 - and 3 -proximal regions of the SPMMV genome providing the first evidence of recombination in genus Ipomovirus, but no recombination events were detected in the characterized genomic regions of SPCSV. Strong purifying selection was implicated on evolution of majority of amino acids of the proteins encoded by the analyzed genomic regions of SPFMV, SPMMV and SPCSV. However, positive selection was predicted on 17 amino acids distributed over the whole the coat protein (CP) in the globally distributed strain C, as compared to only 4 amino acids in the multifunctional CP N-terminus (CP-NT) of strain EA largely restricted geographically to East Africa. A few amino acid sites in the N-terminus of SPMMV P1, the p7 protein and RNA silencing suppressor proteins p22 and RNase3 of SPCSV were also submitted to positive selection. Positively selected amino acids may constitute ligand-binding domains that determine interactions with plant host and/or insect vector factors. The P1 proteinase of SPMMV (genus Ipomovirus) seems to respond to needs of adaptation, which was not observed with the helper component proteinase (HC-Pro) of SPMMV, although the HC-Pro is responsible for many important molecular interactions in genus Potyvirus. Because the centre of origin of cultivated sweetpotato is in the Americas from where the crop was dispersed to other continents in recent history (except for the Australasia and South Pacific region), it would be expected that identical viruses and their strains occur worldwide, presuming virus dispersal with the host. Apparently, this seems not to be the case with SPMMV, the strain EA of SPFMV and the strain EA of SPCSV that are largely geographically confined in East Africa where they are predominant and occur both in natural and agro-ecosystems. The geographical distribution of plant viruses is constrained more by virus-vector relations than by virus-host interactions, which in accordance of the wide range of natural host species and the geographical confinement to East Africa suggest that these viruses existed in East African wild plants before the introduction of sweetpotato. Subsequently, these studies provide compelling evidence that East Africa constitutes a cradle of SPFMV strain EA, SPCSV strain EA, and SPMMV. Therefore, sweet potato virus disease (SPVD) in East Africa may be one of the examples of damaging virus diseases resulting from exchange of viruses between introduced crops and indigenous wild plant species. Keywords: Convolvulaceae, East Africa, epidemiology, evolution, genetic variability, Ipomoea, recombination, SPCSV, SPFMV, SPMMV, selection pressure, sweetpotato, wild plant species Author s Address: Arthur K. Tugume, Department of Agricultural Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, P.O Box 27, FIN-00014, Helsinki, Finland. Email: tugume.arthur@helsinki.fi Author s Present Address: Arthur K. Tugume, Department of Botany, Faculty of Science, Makerere University, P.O. Box 7062, Kampala, Uganda. Email: aktugume@botany.mak.ac.ug, tugumeka@yahoo.com

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1. How a symbiosis originates and is maintained are important evolutionary questions. Symbioses in myrmecophytes (plants providing nesting for ants) are believed to be maintained by protection and nutrients provided by specialist plant-ants in exchange for nesting spaces (called domatia) and nourishment offered by ant-plants. However, besides the benefits accrued from housing protective ants, the mechanisms contributing to the fitness advantages of bearing domatia have rarely been examined, especially because the domatia trait is usually constitutively expressed, and many myrmecophytes have obligate mutualisms with single ant species resulting in invariant conditions. 2. In the unspecialized ant-plant Humboldtia brunonis (Fabaceae) that offers extrafloral nectar to ants, only some plants produce domatia in the form of hollow internodes. These domatia have a self-opening slit making them more prone to interlopers and are occupied mostly by non-protective ants and other invertebrates, especially arboreal earthworms. The protection mutualism with ants is restricted in geographical extent, occurring only at a few sites in the southernmost part of this plant's range in the Western Ghats of India. 3. We examined nutrient flux from domatia residents to the plant using stable isotopes. We found that between 9% (earthworms) and 17% (protective or non-protective ants) of nitrogen of plant tissues nearest the domatium came from domatia inhabitants. Therefore, interlopers such as earthworms and non-protective ants contributed positively to the nitrogen budget of localized plant modules of this understorey tree. N-15-enriched feeding experiments with protective ants demonstrated that nutrients flowed from domatia inhabitants to nearby plant modules. Fruit set did not differ between paired hand-pollinated inflorescences on domatia and non-domatia bearing branches. This was possibly due to the nutrient flux from domatia to adjacent branches without domatia within localized modules. 4. This study has demonstrated the nutritive role of non-protective ants and non-ant invertebrates, hitherto referred to as interlopers, in an unspecialized myrmecophyte. Our study suggests that even before the establishment of a specialized ant-plant protection mutualism, nutritional benefits conferred by domatia inhabitants can explain the fitness benefits of bearing domatia, and thus the maintenance of a trait that facilitates the establishment of a specialized ant-plant symbiosis.

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CONTENTS: I. U.S.-Japan Cooperation Open Ocean Aquaculture – A Venue for Cooperative Research Between the United States and Japan.............................................................................. 1 C. Helsley II. Growth, Nutrition and Genetic Diversity Daily Ration of Hatchery-Reared Japanese Flounder Paralichthys olivaceus as an Indicator of Release Place, Time and Fry Quality. In situ Direct Estimation and Possibility of New Methods by Stable Isotope............................ 7 O. Tominaga, T. Seikai, T. Tsusaki, Y. Hondo, N. Murakami, K. Nogami, Y. Tanaka and M. Tanaka Nucleic Acids and Protein Content as a Measure to Evaluate the Nutritional Condition of Japanese Flounder Paralichthys olivaceus Larvae and Juveniles........................................................................................................ 25 W. Gwak Genetic Diversity Within and Between Hatchery Strains of Flounder Paralichthys olivaceus Assessed by Means of Microsatellite and Mitochondrial DNA Sequencing Analysis...................................................................... 43 M. Sekino, M. Hara and N. Taniguchi Tracking Released Japanese Flounder Paralichthys olivaceus by Mitochondrial DNA Sequencing................................................................................ 51 T. Fujii Preliminary Aspects of Genetic Management for Pacific Threadfin Polydactylus sexfilis Stock Enhancement Research in Hawaii........................................ 55 M. Tringali, D. Ziemann and K. Stuck Enhancement of Pacific Threadfin Polydactylus sexfilis in Hawaii: Interactions Between Aquaculture and Fisheries............................................................. 75 D. Ziemann Aquaculture and Genetic Structure in the Japanese Eel Anguilla japonica..................... 87 M. Katoh and M. Kobayashi Comparative Diets and Growth of Two Scombrid Species, Chub Mackerel Scomber japonicus and Japanese Spanish Mackerel Scomberomorus niphonius, in the Central Seto Inland Sea, Japan.................................. 93 J. Shoji, M. Tanaka and Tsutomu Maehara iii Evaluating Stock Enhancement Strategies: A Multi-disciplinary Approach................... 105 T. M. Bert, R.H. McMichael, Jr., R.P. Cody, A. B. Forstchen, W. G. Halstead, K. M. Leber, J. O’Hop, C. L. Neidig, J. M. Ransier, M. D. Tringali, B. L. Winner and F. S. Kennedy III. Physiological and Ecological Applications Predation on Juvenile Chum Salmon Oncorhynchus keta by Fishes and Birds in Rivers and Coastal Oceanic Waters of Japan................................... 127 K. Nagasawa and H. Kawamura Interaction Between Cleaner and Host: The Black Porgy Cleaning Behavior of Juvenile Sharpnose Tigerfish Rhyncopelates Oxyrhynchus in the Seto Inland Sea, Western Japan............................................................................. 139 T. Shigeta, H. Usuki and K. Gushima IV. Case Studies Alaska Salmon Enhancement: A Successful Program for Hatchery and Wild Stocks............................................................................................... 149 W. Heard NMFS Involvement with Stock Enhancement as a Management Tool........................... 171 T. McIlwain Stock Enhancement Research with Anadromous and Marine Fishes in South Carolina...................................................................................... 175 T. I. J. Smith, W. E. Jenkins, M. R. Denson and M. R. Collins Comparison of Some Developmental, Nutritional, Behavioral and Health Factors Relevant to Stocking of Striped Mullet, (Mugilidae), Sheepshead (Sparidae), Common Snook (Centropomidae) and Nassau Groupers (Serranidae)........................... 191 J. W. Tucker Jr. and S. B. Kennedy Participants in the Thirtieth U.S.-Japan Meeting on Aquaculture................. Inside Back Cover iv (PDF has 204 pages.)

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Lionfish, Pterois volitans and P. miles, are native to the Indo-Pacific and have recently invaded the Western Atlantic Ocean. Strategies for control of this invasion have included limited removal programs and promotion of lionfish consumption at both local and commercial scales. We demonstrate that lionfish meat contains higher levels of healthy n-3 fatty acids than some frequently consumed native marine fish species. Mean lionfish fillet yield was 30.5% of the total body wet weight, a value that is similar to that of some grouper and porgy species. A sensory evaluation indicated that lionfish meet the acceptability threshold of most consumers.

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ABSTRACT: At a large North Sea pockmark, with active methane seeps, surface sediments were found to have higher insoluble sulphide concentrations than sedlments from the surrounding area. The fauna of the pockmark was characterized by 2 species which have not pi-evlously been reported from the Fladen Ground in the northern North Sea. These species were a b~valve, Thyasira sarsi (which is known to contain endosymbiotic sulphur-oxidising bacteria) and a mouthless and gutless nematode, Astomonerna sp., which also contains endosymbiotic bacteria The nematode was the dominant meiofauna species in the pockmark sediments. Both macro-lnfauna and total nematodes were in low abundance in samples taken from the base of the pockmark. Sediment samples from the pockmark contained numerous otoliths, implying that substantial winnowing of the sediment had taken place. This was supported by studies on the sulphide concentrations in the sediment which showed multiple layering of the sediments on the sides of the pockmark, suggesting displacement. The carbon isotope compositions (6I3c) of the tissues of benthic animals from in and around the pockmark were generally in the range -16 to -2O%, indicating that little methane-derived carbon was contributing to their nutrition. T sarsi had the most 13c-depleted tissues, -31.4 to -35.1 L, confirming the nutritional dependence of this species on chemoautotrophic bacteria that utilize reduced sulphur.

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Tese de doutoramento, Biologia (Biologia Marinha e Aquacultura), Universidade de Lisboa, Faculdade de Ciências, 2015

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The fruit of the date palm (Phoenix dactylifera L.) is a rich source of dietary fibre and polyphenols. We have investigated gut bacterial changes induced by the whole date fruit extract (digested date extract; DDE) and its polyphenol-rich extract (date polyphenol extract; DPE) using faecal, pH-controlled, mixed batch cultures mimicking the distal part of the human large intestine, and utilising an array of microbial group-specific 16S rRNA oligonucleotide probes. Fluorescence microscopic enumeration indicated that there was a significant increase in the growth of bifidobacteria in response to both treatments, whilst whole dates also increased bacteroides at 24 h and the total bacterial counts at later fermentation time points when compared with DPE alone. Bacterial metabolism of whole date fruit led to the production of SCFA, with acetate significantly increasing following bacterial incubation with DDE. In addition, the production of flavonoid aglycones (myricetin, luteolin, quercetin and apigenin) and the anthocyanidin petunidin in less than 1 h was also observed. Lastly, the potential of DDE, DPE and metabolites to inhibit Caco-2 cell growth was investigated, indicating that both were capable of potentially acting as antiproliferative agents in vitro, following a 48 h exposure. This potential to inhibit growth was reduced following fermentation. Together these data suggest that consumption of date fruits may enhance colon health by increasing beneficial bacterial growth and inhibiting the proliferation of colon cancer cells. This is an early suggestion that date intake by humans may aid in the maintenance of bowel health and even the reduction of colorectal cancer development.