Differences in fish assemblage structures between fragmented and continuous seagrass beds in Trang,southern Thailand

Fish assemblage structures in fragmented and continuous seagrass habitats in Trang Province, Thailand, were examined in detail to elucidate the effects of habitat fragmentation. The assemblage structures clearly differed: fish species diversity was apparently higher in the fragmented seagrass beds, although total fish numbers did not differ between them. A total of 37 fish species were collected, including 24 and 34 species from the continuous and fragmented beds, respectively. Thirteen species were restricted to the fragmented beds, compared with three restricted to the continuous beds. In addition, eight species were more abundant in the fragmented beds and only two in the continuous beds. Such differences may have arisen, at least in part, from differences in microhabitat diversity and the relative amounts of microhabitats between the two habitat types, as well as specific microhabitat preferences of the resident fishes. Although fragmented beds supported greater fish species diversity at the present study sites, it is axiomatic that habitat fragmentation caused by anthropogenic disturbance is unacceptable, with seagrass-habitat conservation being essential for both the preservation of high overall biodiversity and the successful management of local fisheries.     

Kujigamberol, a new dinorlabdane diterpenoid isolated from 85million years old Kuji amber using a biotechnological assay

A new compound, 15,20-dinor-5,7,9-labdatriene-18-ol (1), named kujigamberol, was isolated from amber, fossilized tree resin from the Kuji area in Japan, has been dated as being 85 million years old (late Cretaceous). Kujigamberol was identified using the hypersensitive mutant yeast (zds1? erg3? pdr1? pdr3?) with respect to Ca²⁺-signal transduction. The structure was elucidated on the basis of spectroscopic analysis including 1D NMR, 2D NMR and HR-EI-MS. It was different from known diterpenoids with a similar activity isolated from Baltic amber (agathic acid 15-monomethyl ester (2), dehydroabietic acid (3) and pimaric acid (4)). Kujigamberol showed glycogen synthase kinase-3β (GSK-3β) inhibition activity involving the growth restored activity against the mutant yeast and was cytotoxic to HL60 cells (IC₅₀ = 19.6 μM).     

Effect of α-cyclodextrin-allyl isothiocyanate on ruminal microbial methane production in vitro

The objective of the present study was to investigate the effects of α‐cyclodextrin‐allyl isothiocyanate (CD‐AI) on ruminal microbial methane production and rumen fermentation of corn starch, soluble potato starch or hay plus concentrate (1.5:1) by mixed rumen microorganisms. Diluted rumen fluid (30 mL) was incubated anaerobically at 38°C for 6 and 24 h with or without CD‐AI (0, 0.4, 0.8, 1.6 and 3.2 g/L). The pH of the medium was unchanged by CD‐AI in all substrates. The molar proportion of acetate was decreased and propionate was increased with a corresponding decrease in acetate : propionate ratio (P < 0.05). Total volatile fatty acids and butyrate were increased (P < 0.05). Ammonia‐N was decreased (P < 0.05). Except with soluble potato starch, numbers of protozoa were unchanged after 6 h. As concentration of CD‐AI increased from 0 to 3.2 g/L, fermentation of corn starch, soluble potato starch and hay plus concentrate resulted in decreased (P < 0.05) methane production of 49–100% (6 h) and 14–100% (24 h); 39–100% (6 h) and 16–100% (24 h); and 45–100% (6 h) and 17–100% (24 h), respectively. When hay plus concentrate was used as substrate, methanogenic bacteria were decreased (P < 0.05) with 0.8 g/L of CD‐AI after 6 h. Excluding the lower dose level (0.4 g/L) of CD‐AI, digestibility of neutral detergent fiber of hay plus concentrate was decreased (P < 0.05) after 24 h. A suitable level of CD‐AI could therefore be used as a supplement to inhibit methane production and improve rumen fermentation without detrimental effects on fiber digestion.     

First step of non‐fish meal,non‐fish oil diet development for red seabream, (Pagrus major), with plant protein sources and microalgae Schizochytrium sp

A feeding experiment was conducted to develop non‐fish meal and non‐fish oil diet for red seabream by using plant protein source and Schizochytrium meal which is rich in 22:6n‐3 (DHA). Three iso‐nitrogenous and iso‐lipidic experimental diets were prepared (CP 41.2% ± 0.4%, CL 16.4% ± 1%). Control diet contained both fish meal (40%) and fish oil (6%). In the second diet, fish meal was replaced by plant meals (soy protein concentrate, soybean meal, corn gluten meal) [FO]. In the third diet, fish meal and fish oil were replaced by algae meal (Schizochytrium sp. powder) and plant proteins [AO]. Duplicated groups of juvenile red seabream (8.8 g ± 1.5) were fed the experimental diets for 12 weeks to near satiation. There was no statistical difference among treatment in specific growth rate. Feed conversion ratio of AO diet group was higher than that of control. In wet basis, whole body protein level was significantly higher in AO diet than FO group while lipid content was lower than control group. In fatty acid profile, AO group had significantly lower 18:4n‐3, 20:4n‐3, 22:5n‐3 and 20:5n‐3 (EPA) level, but significantly higher 18:3n‐3 and DHA level than the other two diet fed fish. The results might suggest that further developments in microalgae diet offer a promising lipid source of n‐3 PUFA as essential fatty acid on marine fish. And it showed possibility to develop non‐fish meal and non‐fish oil feed for marine aquaculture fish by using microalgae.     

Development and age‐related change of cerebrovascular noradrenergic (NA) innervation in the Japanese quail

Development of cerebrovascular noradrenergic (NA) innervation was investigated in the Japanese quail, using histofluorescence technique and quantitative analysis. Cerebral perivascular NA nerves arose from the cerebral carotid (CCA), internal ethmoidal (IEA) and vertebral (VA) arteries before hatching, with the first appearance on the CCA and IEA at embryonic day (E) 8 and of the VA at E14. Nerves arising from the IEA were greater in number and spread more rapidly than those from the CCA and VA. On E16, fluorescent fiber bundles lying on the anterior circulation subdivided rapidly into thin fibers. Consequently, the number of NA nerves over the arterial system increased greatly at hatching, particularly along the distal portion of the anterior ramus. At the same developmental stage, all the major arteries of the anterior and posterior circulation were almost entirely covered by NA nerves. The abrupt reorganization of cerebrovascular NA innervation in newborn quails may be related to some specific trophic and vasomotor roles for structural and functional improvement of the cerebral circulation that is required for its brain differentiation at this critical period of development. The supply of NA nerves to the anterior and posterior circulations sequentially increased during development from posthatching day (P) 1–15. Plexuses of NA nerves in each of the major cerebral arteries at P22 and P42–50 were similar in meshwork construction to each other, and to those seen at P15. Likewise, there was no clear statistical difference in the nerve density of the corresponding arteries among the three posthatching ages, except for the caudal basilar artery.     

In vitro safety assessments and antimicrobial activities of Lactobacillus rhamnosus strains isolated from a fermented mare's milk

Safety and probiotic characteristics such as antimicrobial activities of three Lactobacillus rhamnosus strains, FSMM15, FSMM22 and FSMM26, previously isolated as potential probiotics from fermented mare's milk were investigated. The three FSMM strains were susceptible to ampicillin, gentamycin, kanamycin, streptomycin, tetracycline and chloramphenicol, whereas they were resistant to erythromycin (minimal inhibitory concentration (MIC) = 4?8 µg/mL) and clindamycin (MIC = 4 µg/mL); bioconversion of bile salts, hemolytic activity and mucin degradation activity were negative; enzymatic activities of α‐chymotrypsin and β‐glucosidase were detected, but those of α‐galactosidase, β‐glucuronidase and N‐acetyl‐β‐glucosaminidase, were undetectable. Among the strains, strain FSMM15 was chosen as a safer probiotic candidate due mainly to the lack of plasminogen binding ability. Despite lower acid production of strain FSMM15 than others, its cell‐free culture supernatant inhibited growths of Salmonella Typhimurium LT‐2, Shigella sonnei , Listeria monocytogenes , and Escherichia coli O157 with comparable levels of ampicillin, suggesting a favorable aspect of strain FSMM15 as a probiotic strain.     

Localization of aquaporin water channels in the airway of the musk shrew (Suncus murinus) and the rat

Aquaporins (AQPs) constitute a family of water channels that facilitate membrane water permeability in various tissues of animals. In this study, we compared the expression and localization of AQPs in the respiratory system of the musk shrew (Suncus murinus), which is an insectivore, and the rat by immunohistochemical methods. In both the musk shrew and the rat, AQP1 was expressed throughout the airway in endothelial cells of subepithelial blood vessels and in nasal submucosal fibroblasts. AQP3 and AQP4 were detected in neither the epithelium nor the subepithelial layer of the musk shrew airway, but were abundant in the rat airway epithelium. Musk shrew AQP5 was distributed in the superficial epithelial cells facing the airspaces and in submucosal glandular cells, but, unlike in the rat, not in lung alveolar cells. Additionally, the expression patterns of AQP4 and AQP5 of the musk shrew were partly similar to those of the human previously reported, absence of AQP4 and presence of AQP5 in the upper airway. The expression differences of AQPs between species in the airway indicate that the physiological importance of each AQP may be different in each species.     

Mutual antagonism between sterol demethylation inhibitors and phosphorothiolate fungicides on Pyricularia oryzae and the implications for their mode of action

Joint action between a phosphorothiolate (PTL) fungicide, iprobenfos, and a sterol demethylation inhibitor (DMI), pefurazoate, was tested by crossed paper technique on three types of field isolates of Pyricularia oryzae Cavara that differed in PTL sensitivity and metabolism. Mutual antagonism in anti-fungal action between iprobenfos and pefurazoate was observed in a wild-type field isolate of the fungus sensitive to PTL and in an isolate moderately resistant to PTL, but not in a PTL-resistant isolate lacking the ability to metabolize PTL. Antagonism of the antifungal action of iprobenfos by pefurazoate seemed to be a result of inhibition of activation by cleavage of the P-S bond of iprobenfos mediated by mixed-function oxygenase (mfo) activity, while antagonism of the anti-fungal action of pefurazoate by iprobenfos may be caused by the binding of pefurazoate by large amounts of an iprobenfos-induced mfo which results in reduced inhibition of ergosterol biosynthesis. In the PTL-resistant isolate, the mutually antagonistic action was not observed, presumably because the induction of the mfo-metabolizing iprobenfos was lacking. Similar antagonism was also observed when another PTL, edifenphos, was used instead of iprobenfos, and when other DMIs, propiconazole, prochloraz and hexaconazole were used instead of pefurazoate. The results of the present experiment indicate that DMIs may also bind to and inhibit an inducible type of fungal mfo which metabolizes xenobiotics, and that PTLs may be activated by an mfo prior to their anti-fungal action.