Effects of cooked molasses blocks and fermentation extract or brown seaweed meal inclusion on intake, digestion, and microbial efficiency in steers fed low-quality hay.
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Five ruminally, duodenally, and ileally cannulated steers (376 +/- 8.1 kg of initial BW) were used in a 5 x 5 Latin square to evaluate effects of cooked molasses block supplementation and inclusion of fermentation extract (Aspergillus oryzae) or brown seaweed meal (Ascophyllum nodosum) on intake, site of digestion, and microbial efficiency. Diets consisted of switchgrass hay (6.0% CP; DM basis) offered ad libitum, free access to water, and one of three molasses blocks (0.341 kg of DM/d; one-half at 0600 and one-half at 1800). Treatments were no block (control), block with no additive (40.5% CP; POS), block plus fermentation extract bolused directly into the rumen via gelatin capsules (2.0 g/d; FS), fermentation extract included in the block (2.0 g/d; FB), and seaweed meal included in the block (10 g/d; SB). Steers were adapted to diets for 14 d followed by a 7-d collection period. Overall treatment effect on hay OM intake tended (8.1 vs. 7.6 +/- 0.5 kg/d; P = 0.14) to increase with block supplementation. Total OM intake (8.4 vs. 7.6 +/- 0.5 kg/d; P = 0.01) increased in steers consuming block compared with control. Apparent and true ruminal OM digestibility increased (P = 0.05) with block consumption. Steers fed SB had greater (P = 0.10) true ruminal OM digestibility compared with steers fed POS (61.0 vs. 57.9 +/- 1.6%). True ruminal CP digestibility increased (P = 0.01) with block supplementation compared with control (37.5 vs. 23.6 +/- 3.7%). Addition of fermentation extract did not affect intake or digestion. Treatments did not alter ruminal pH, total VFA, or individual VFA proportions; however, ruminal ammonia increased (P = 0.01) with block supplementation. In situ disappearance rates of hay DM (3.14 +/- 0.44 %/h), NDF (3.18 +/- 0.47 %/h), and ADF (3.02 +/- 0.57 %/h) were not altered by treatment. Seaweed block increased (P = 0.01) slowly degraded CP fraction compared with POS (39.5 vs. 34.0 +/- 2.07%). Similarly, SB increased (P = 0.01) the extent of CP degradability (74.2 vs. 68.9 +/- 1.81%). No treatment effects (P = 0.24) were observed for microbial efficiency. Block supplementation increased intake, and use of brown seaweed meal seemed to have beneficial effects on forage digestibility in low-quality forage diets. (+info)
Isolation and structure determination of algicidal compounds from Ulva fasciata.
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Thirty-seven species of seaweeds including 10 Chlorophyta, 13 Phaeophyta, and 14 Rhodophyta collected from the coast of Nagasaki Prefecture, Japan, were screened for algicidal activity against the red-tide phytoplankton Heterosigma akashiwo. The green alga Ulva fasciata (Ulvaceae, Chlorophyta) showed the strongest algicidal activity among the seaweeds tested. Bioassay-guided fractionation of the methanol extract of U. fasciata led to isolation of three algicidal compounds whose structures were determined to be hexadeca-4,7,10,13-tetraenoic acid (HDTA), octadeca-6,9,12,15-tetraenoic acid (ODTA), and alpha-linolenic acid on the basis of spectroscopic information. These polyunsaturated fatty acids (PUFAs) showed potent algicidal activity against H. akashiwo (LC(50) 1.35 microg/ml, 0.83 microg/ml, and 1.13 microg/ml for HDTA, ODTA, and alpha-linolenic acid, respectively), and the result demonstrated the potential of these PUFAs for practical harmful algal bloom control. (+info)
Isolation and molecular characterization of toxigenic Vibrio parahaemolyticus from the Kii Channel, Japan.
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Studies were conducted on the ecology of potentially pathogenic Vibrio parahaemolyticus in three coastal areas of Kii Channel, Tokushima, Japan. Seawater and seaweed samples were collected seasonally between June 2003 and May 2004. Total and toxigenic strains of V. parahaemolyticus were isolated using most probable number culture and colony blot hybridization. Toxigenic strains were serotyped and further characterized by random amplified polymorphic DNA (RAPD) and ribotyping. Six thousand strains of V. parahaemolyticus were isolated and 18 were found positive for tdh. V. parahaemolyticus were detected in all samples during summer and autumn, and from some samples during winter and spring. Among the toxigenic strains seven serotypes, five ribotypes and RAPD patterns were observed. Seven strains belonged to O3:K6 clone with identical ribotypes and RAPD patterns to that of a pandemic reference strain. The presence of toxigenic V. parahaemolyticus with pandemic potential might indicate a human health risk due to consumption of marine food sources. (+info)
PCR-identification of Dunaliella salina (Volvocales, Chlorophyta) and its growth characteristics.
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The saline pond microalga, Dunaliella salina (Dunal) Teod. maintained in De Walne's (basal) medium under laboratory conditions was confirmed by amplifying the chromosomal DNA of the microalga by PCR with specific primers MA1 and MA2. Seaweed extracts obtained from Sargassum wightii and Ulva lactuca were amended separately at 1.0%, 1.5%, 2.0% and 2.5% levels to the basal medium in order to assess their potential on the growth and concentration of pigments, viz. Chl a, Chl b and beta-carotene of the alga. beta-Carotene was isolated and visible absorption spectrum was taken at 443 and 475 nm confirmed the presence of 9-cis-beta-carotene and all-trans-beta-carotene isomers. Maximum yield, highest division rate (mu) and highest pigment concentrations were observed in the cells grown in 1.5% S. wightii and 2.0% U. lactuca amended medium and these cells were subjected to DAPI staining. The results of epifluorescence microscopy and image analysis revealed a significant enhancement of the cell and nuclear area of the microalgae. (+info)
Hydrodynamic consequences of flexural stiffness and buoyancy for seaweeds: a study using physical models.
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An upright posture in the water column may expose benthic marine organisms to faster flow higher in the water column than near the substratum, potentially increasing rates of mass exchange while also exposing the organisms to higher hydrodynamic forces. Benthic organisms maintain upright postures in the water column by one of two mechanisms, stiffness or buoyancy. Turbinaria ornata is a tropical macroalga that uses either buoyancy or flexural stiffness (EI), depending on its flow habitat. This study used physical models of T. ornata to compare the effect of different magnitudes of these two mechanisms on relative water velocity and hydrodynamic forces in both unidirectional and wavy flow. Models of the alga were constructed to span and exceed natural levels of T. ornata's EI and buoyancy. Models with high EI and high buoyancy maintained upright postures in both unidirectional flow and waves, and experienced higher forces than models with low EI and moderate or low buoyancy that deflected in the direction of water motion. In waves, buoyant models that were deflected by high velocity rebounded back into upright positions when the flow slowed. Non-buoyant, flexible models were also pushed over by flow but lacked the ability to rebound upright, which led to decreased force in unidirectional flow, but high force in waves. (+info)
Phycicoccus jejuensis gen. nov., sp. nov., an actinomycete isolated from seaweed.
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A marine actinomycete strain, designated KSW2-15(T), was isolated from a dried seaweed sample collected from a sandy beach on the coast of Jeju in the Republic of Korea. The organism produced non-motile, non-endospore-forming, Gram-positive, coccoid cells. The colonies were circular, translucent and yellow in colour with entire margins. meso-Diaminopimelic acid was present as the diamino acid of the peptidoglycan. The acyl type of the muramic acid was acetyl. Mycolic acids were not present. The predominant menaquinone was MK-8(H(4)). The polar lipids were phosphatidylethanolamine, phosphatidylinositol and diphosphatidylglycerol. The major cellular fatty acids were of the saturated, unsaturated and iso-branched methyl types. The DNA G+C content was 74 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain KSW2-15(T) formed a loose association with 'Candidatus Nostocoida limicola', within the radiation of the family Intrasporangiaceae of the suborder Micrococcineae. The organism showed the highest levels of sequence similarity with 'Candidatus Nostocoida limicola' (96.1 %), Terrabacter tumescens (96.1 %) and Terrabacter terrae (96.0 %). The levels of 16S rRNA gene sequence similarity between the isolate and members of other genera of the family Intrasporangiaceae were in the range 92.1-95.5 %. On the basis of the polyphasic evidence, the isolate should be classified within a novel genus and species, for which the name Phycicoccus jejuensis gen. nov., sp. nov. is proposed. The type strain of Phycicoccus jejuensis is strain KSW2-15(T) (=KCCM 42315(T)=NRRL B-24460(T)). (+info)
Extraction of hydrocarbons from seaweed samples using sonication and microwave-assisted extraction: a comparative study.
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A sonication method is compared with a microwave-assisted extraction method for recovering polycyclic aromatic hydrocarbons and aliphatic hydrocarbons from seaweed and acid humic samples. Different extracting solvents and adsorbents for the purification step are tested. For the sonication extraction, 10 g of the sample are extracted in an ultrasonic bath (60 degrees C for 15 min with 20 mL of hexane). For the microwave-assisted extraction two steps are carried out, each step at 90 degrees C under pressure in closed vessels with 20 mL of hexane for 10 min at 950 W. A clean-up step is performed for both extraction techniques. The results indicate that the recovery of hydrocarbons is dependent on both the extraction technique and the type of matrix. The most suitable technique appears to be sonication employing hexane as the extraction solvent. The recoveries obtained for aliphatic hydrocarbons are higher than those achieved for the polycyclic aromatic hydrocarbons, with values ranging within 81-109% and 40-76%, respectively. (+info)
Aeromicrobium tamlense sp. nov., isolated from dried seaweed.
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A Gram-positive, non-motile, rod-shaped actinomycete strain, designated SSW1-57T, was isolated from a dried seaweed sample from the coast of Jeju Island, Republic of Korea and subjected to a polyphasic taxonomic study. A neighbour-joining tree based on 16S rRNA gene sequences showed that the organism was related to members of the family Nocardioidaceae and formed a separate branch at the base of a taxon encompassing members of the genus Aeromicrobium, whereas it occupied an intermediate position between Aeromicrobium alkaliterrae-Aeromicrobium marinum and Aeromicrobium erythreum-Aeromicrobium fastidiosum clusters in maximum-parsimony and maximum-likelihood trees. The phylogenetic association of the isolate with the genus Aeromicrobium was supported by the following chemotaxonomic properties: ll-diaminopimelic acid in the peptidoglycan, MK-9(H4) as the major menaquinone and major fatty acids cis-9-octadecenoic acid, hexadecanoic acid, 10-methyl octadecanoic acid and 2-hydroxy hexadecanoic acid. The polar lipid profile contained phosphatidylinositol, diphosphatidylglycerol and phosphatidylglycerol. Levels of 16S rRNA gene sequence similarity between the novel organism and the type strains of the four recognized Aeromicrobium species were in the range 96.5-96.7 %. On the basis of phylogenetic analyses and phenotypic data, it is proposed that the organism should be classified as representing a novel species of the genus Aeromicrobium, with the name Aeromicrobium tamlense sp. nov. The type strain is SSW1-57T (=JCM 13811T=NRRL B-24466T). (+info)