Optimization of aquatic-terrestrial ecosystem in relation to soil nitrogen status for the cultivation of fish and aquatic food crops of the Indian subtropics.
(1/10)
A case study was undertaken during wet and postwet seasons to improve the perennial and alternate submerged saucer-shaped ponded lands (tal and semi-tal lands) in the coasts and northeastern plains of the Indian subtropics through pisciculture and cultivation of starch- and protein-rich aquatic food crops like water chestnut (Trapa bispinosa Roxb.) and makhana or fox nut (Euryale ferox Salisb.). The study revealed that the physico-chemical properties of soils (pH, organic C, organic matter, available N, P, and K) as well as quality of water (pH, EC, BOD, COD, CO3 +, HCO3-, NO3-N, SO4-S-, and Cl-), growing fish, makhana, and water chestnut was remarkably influenced by different moisture regimes and exhibited a significant improvement of soil health. The amount of organic C, available N, P, and K content were found significantly highest in the treatment where makhana was grown under alternate flooding and drying situation with a depth >2 m as compared to other treatments. Such enrichment of soil fertility, particularly in available N and P content, might be due to the accumulation of considerable amounts of biomass and fish excreta and their subsequent decomposition in situ in the soils. Therefore, the present study suggests that the N-enriched soil may effectively be utilized further for growing subsequent arable crops surroundings during summer season, which not only saves the amount of applied N fertilizer but also increases the apparent N efficiency with simultaneous increase in yield, and would benefit the farmers in this region. (+info)
Stable isotope food web analysis of a large subtropical lake: alternative explanations for 15N enrichment of pelagic vs. littoral fisheries.
(2/10)
The food webs of littoral, pelagic, and littoral-pelagic ecotone (interface) regions of a large subtropical lake were investigated using stable isotope ratio methods, expanding the focus of a previous fish-only study to include other food web components such as primary producers and invertebrates. In these food webs, delta13C increased approximately 4 per thousand and delta15N increased approximately 10 per thousand from primary producers to fish. The delta15N of fish was approximately 9 per thousand in the littoral zone, approximately 10 per thousand in the ecotone, and approximately 12 per thousand in the pelagic zone. The cross-habitat enrichment in fish 15N corresponded with both an increase in the size of fish and an increase in the d15N of primary consumers (mollusks). Despite larger body size in the pelagic zone, fish in all three habitats appear to occur at the same average trophic level (TL = 4), assuming an enrichment factor of 3.4 per thousand per trophic level, and normalizing to the delta15N of primary consumers. (+info)
Odor-taste interactions: effects of attentional strategies during exposure.
(3/10)
Through repeated pairings with a tastant such as sucrose, odors are able to take on the tastant's qualities, e.g. by becoming more sweet smelling. When such odors are subsequently experienced with a sweet tastant in solution, the mixture is often given a higher sweetness rating than the tastant alone. Odor-induced taste enhancement appears to be sensitive to whether an odor-taste combination is viewed analytically as a set of discrete qualities, or synthetically as a flavor. The present research attempted to determine if adoption of these different perceptual approaches during co-exposure with sucrose would influence the extent to which an odor would become sweet smelling and subsequently enhance sweetness intensity. In Experiment 1, subjects received multiple exposures to mixtures of sucrose with low sweetness, low familiarity odors or, as a control, the odors and sucrose solutions separately. Two groups that received mixtures made intensity ratings that promoted either synthesis or analysis of the individual elements in the mixtures. The odors became sweeter smelling irrespective of group. Only adopting a synthetic strategy produced odors that enhanced sweetness in solution. However, these effects were also shown with a 'non-exposed' control odor. This could be accounted for if the single co-exposure with sucrose that all odors received in the pre-test was able to produce sweeter odors. A second experiment confirmed this prediction. Thus, while even a single co-exposure with sucrose is sufficient to produce a sweeter odor, the adoption of a synthetic perceptual strategy during the co-exposure is necessary to produce an odor that will enhance sweetness. These data are consistent with associative leaning accounts of how odors take on taste qualities and also support the interpretation that these effects reflect the central integration of odors and tastes into flavors. (+info)
Curtobacterium ammoniigenes sp. nov., an ammonia-producing bacterium isolated from plants inhabiting acidic swamps in actual acid sulfate soil areas of Vietnam.
(4/10)
The ammonia-producing bacteria B55(T), CA73, SA69 and SA72 were isolated from the waterweeds Ludwigia adscendens (B55(T)) and Eleocharis dulcis (CA73, SA69 and SA72) grown in highly acidic swamps (pH 2-4) in actual acid sulfate soil areas of Vietnam. The isolates were Gram-positive, irregular rod-shaped, non-spore-forming bacteria. On the basis of 16S rRNA gene sequence similarity, strain B55(T) was shown to belong to the genus Curtobacterium of the class Actinobacteria. Chemotaxonomic data (MK-9 as major isoprenoid quinone, d-ornithine as cell-wall diamino acid, acetyl as the acyl type of peptidoglycan) supported the affiliation of all four strains to this genus. Although their 16S rRNA gene sequence similarity was 99 % to species with validly published names within the genus, they formed a group that was distinct in the phylogenetic tree, and DNA-DNA relatedness values to these established species were less than 10 %. The results of physiological and biochemical tests and major fatty acids (cyclohexyl-C(17 : 0), anteiso-C(17 : 0) and cyclohexyl-C(19 : 0)) allowed phenotypic differentiation of these strains from the species of Curtobacterium with validly published names. Therefore, strains B55(T), CA73, SA69 and SA72 represent a novel species, for which the name Curtobacterium ammoniigenes sp. nov. is proposed. The type strain is B55(T) (=NBRC 101786(T)=VTCC D6-11(T)=JCM 14609(T)). (+info)
Identification of major phenolic compounds of Chinese water chestnut and their antioxidant activity.
(5/10)
Chinese water chestnut (CWC) is one of the most popular foods among Asian people due to its special taste and medical function. Experiments were conducted to test the antioxidant activity and then determine the major phenolic compound components present in CWC. CWC phenolic extract strongly inhibited linoleic acid oxidation and exhibited a dose-dependent free-radical scavenging activity against alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radicals, superoxide anions and hydroxyl radicals, which was superior to ascorbic acid and butylated hydroxytoluene (BHT), two commercial used antioxidants. Furthermore, the CWC extract was found to have a relatively higher reducing power, compared with BHT. The major phenolic compounds present in CWC tissues were extracted, purified and identified by high-performance liquid chromatograph (HPLC) as (-)-gallocatechin gallate, (-)-epicatechin gallate and (+)-catechin gallate. This study suggests that CWC tissues exhibit great potential for antioxidant activity and may be useful for their nutritional and medicinal functions. (+info)
Burkholderia heleia sp. nov., a nitrogen-fixing bacterium isolated from an aquatic plant, Eleocharis dulcis, that grows in highly acidic swamps in actual acid sulfate soil areas of Vietnam.
(6/10)
Burkholderia acidipaludis sp. nov., aluminum-tolerant bacteria isolated from Chinese water chestnut (Eleocharis dulcis) growing in highly acidic swamps in South-East Asia.
(7/10)
Evaluation of in vitro antioxidant potential of aqueous extract of Trapa natans L. fruits.
(8/10)
In the present study, the in vitro antioxidant potential of aqueous extract of Trapa natans L. fruits rind was investigated. The extract was found to contain a large amount of polyphenols and also exhibited an immense reducing ability. The total content of phenolic, flavonoid and tannin compounds was estimated as 63.81 mg of gallic acid equivalents/g of dry material, 21.34 mg of rutin equivalents/g of dry material and 17.11 mg of total tannin equivalent /g of dry material, respectively. IC50 values for different antioxidant model were calculated as 128.86 microg/mL for DPPH radicals, 97.65 microg/mL for O2*-, 148.32 microg/mL for H2O2 and 123.01 microg/mL for NO, respectively. Reducing power and inhibition of *OH radical-induced BSA oxidation were also determined. The data obtained in the present study suggest that the aqueous extract of Trapa natans L. fruit rind have significant antioxidant activity against free radicals. (+info)