Culture-based fisheries in small reservoirs in northern Vietnam: effect of stocking density and species combinations

This study was conducted in 20 reservoirs, ranging in size from 4 to 30 ha, in the mountainous, northern region of Vietnam, in ThaiNguyen and YenBai provinces, over two growth cycles in 2002/03 and 2003/04. The reservoirs are leased by farmers for fishery activities from the provincial administration, and the trials were managed by the lessee farmers. Three species combinations in ratios (by fingerling weight) of grass carp: silver carp: bighead carp: common carp: mrigal 1:2:1:1:3 (A), 1:3:1:1:2 (B) and 1:2:1:1:2 (C) were used as seed stock. The overall mean yield of stocked fish in 2002/03 and 2003/04 growth cycles in reservoirs in ThaiNguyen and YenBai provinces was 165 (±21) and 190 (39), and 287 (±22) and 325 (±24) kg ha^?1 respectively. The yield in reservoirs in both provinces, in both growth cycles and irrespective of the species combinations, increased in relation to stocking density. In reservoirs in ThaiNguyen Province, the species combination B gave the lowest yield (both growth cycles and overall), and differed significantly (P<0.05) from combinations A and C. The stocking efficiency (ratio of the yield of stocked fish in kg ha^?1 to the weight of the stocked fish in kg ha^?1) in reservoirs in ThaiNguyen Province ranged from 2.9 to 5.1 over the two growth cycles and that in YenBai from 2.8 to 3.9. There was no discernible trend between growth cycles and/or between species combinations. The major cost incurred was for fingerling procurement. In all instances, a net profit was accrued. The mean (±standard error (SE)) net profit ha^?1 (in 10³VN dong; approximately 15 500 VND=1 US$) was 885 (±270) and 864 (±214), and 1322 (±176) and 1600 (±150) for the growth cycles 2002/03 and 2003/04 for reservoirs in ThaiNguyen and YenBai provinces respectively. Between the two growth cycles, the net profit increased in eight and three reservoirs from YenBai and ThaiNguyen, respectively, the maximum increase being recorded in Khuan Gio (165%) and Dong Man (39%) reservoirs.     

Soil-solution chemistry in a low-elevation spruce-fir ecosystem,Howland, Maine

Soil solutions were collected monthly by tension and zero-tension lysimeters in a low-elevation red spruce stand in east-central Maine from May 1987 through December 1992. Soil solutions collected by Oa tension lysimeters had higher concentrations of most constituents than the Oa zero-tension lysimeters. In Oa horizon soil solutions growing season concentrations for SO₄, Ca, and Mg averaged 57, 43, and 30 μmol L^?1 in tension lysimeters, and 43, 28, and 19 μmol L^?1 in zero-tension lysimeters, respectively. Because tension lysimeters remove water held by the soil at tensions up to 10 kPa, solutions are assumed to have more time to react with the soil compared to freely draining solutions collected by zero-tension lysimeters. Solutions collected in the Bs horizon by both types of collectors were similar which was attributed to the frequency of time periods when the water table was above the Bs lysimeters. Concentrations of SO₄ and NO₃ at this site were lower than concentrations reported for most other eastern U.S. spruce-fir sites, but base cation concentrations fell in the same range. Aluminum concentrations in this study were also lower than reported for other sites in the eastern U.S. and Ca/Al ratios did not suggest inhibition of Ca uptake by roots. Concentrations of SO₄, Ca, K, and Cl decreased significantly in both the Oa and Bs horizons over the 56-month sampling period, which could reflect decreasing deposition rates for sulfur and base cations, climatic influences, or natural variation. A longer record of measured fluxes will be needed to adequately define temporal trends in solution chemistry and their causes.     

Withanolides from the rhizomes of Dioscorea japonica and their cytotoxicity

Edible yams are tropical crops that serve as important staple foods in many parts of the world. The rhizome of Dioscorea japonica , well-known as "Japanese yam", is a food and medicinal source known as "San Yak" in Korea. Bioassay-guided fractionation and chemical investigation of the extract of this yam resulted in the identification of two new withanolides, named dioscorolide A (1) and dioscorolide B (2). The structures of these new compounds were determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR) techniques, high-resolution mass spectrometry (HRMS), and chemical methods. The cytotoxic activities of the isolates (1 and 2) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) and a human normal cell line (HUVEC) using a sulforhodamine B (SRB) bioassay. Compounds 1 and 2 showed cytotoxicity against tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) with IC(50) values ranging from 6.3 to 26.9 μM and exhibited lower activity against the normal cell line (HUVEC) with IC(50) values ranging from 27.1 to 28.8 μM, suggesting selective toxicity among tumor and normal cells.     

Protective Effects of Platycodon grandiflorum Aqueous Extract on Thioacetamide-induced Fulminant Hepatic Failure in Mice

The aim of the present study was to evaluate the protective activity of aqueous extract from Platycodon grandiflorum (BC703) on thioacetamide (TA)-induced hepatotoxicity in mice. We found that BC703 significantly decreased mortality and the change in serum transaminase following TA administration. The group treated with BC703 at doses of 1, 5, and 10 mg/kg produced significant hepatoprotective effects against TA-induced liver damage by decreasing the activities of serum enzymes, nitric oxide and lipid peroxidation in dose-dependent manners. Histopathological studies further substantiated the protective effect of BC703. These results show the hepatoprotective activity of aqueous extract from Platycodon grandiflorum on thioacetamide-induced fulminant hepatic failure.     

Immune-mediated hemolytic anemia in an eclectus parrot

CASE DESCRIPTION: A 2-year-old female Solomon Island eclectus parrot (Eclectus roratus) was evaluated by a veterinarian because of a 4-day history of progressive lethargy, weakness, poor appetite, and inactivity. The bird was referred to a veterinary teaching hospital for further examination. CLINICAL FINDINGS: Clinicopathologic analyses revealed that the parrot had marked regenerative anemia, autoagglutination, and biliverdinuria. Small, rounded RBCs (thought to be spherocytes) were detected in blood smears. The abnormal findings met the diagnostic criteria for dogs with primary immune-mediated hemolytic anemia. However, analyses of blood samples for lead and zinc concentrations and plasma bile acids concentrations; the use of PCR assays for Chlamydophila psittaci, psittacine circovirus 1 (causative agent of beak and feather disease), and polyomavirus; and microbial culture and Gram staining of feces did not reveal a cause for the hemolytic anemia. TREATMENT AND OUTCOME: Although administration of immunosuppressive doses of cyclosporine was initiated, there was a rapid progression of disease, which lead to death of the parrot before this treatment could be continued long-term. Lack of an identifiable underlying disease (confirmed by complete histologic examinations at necropsy) supported the diagnosis of primary immune-mediated hemolytic anemia. CLINICAL RELEVANCE: Primary immune-mediated hemolytic anemia has not been widely reported in psittacine birds. A comprehensive evaluation and complete histologic examination of tissues to rule out underlying disease processes are required to definitively establish a diagnosis of primary immune-mediated hemolytic anemia in parrots. Primary immune-me-diated hemolytic anemia should be considered as a differential diagnosis for regenerative anemia in a parrot.     

猪苓的人工培养条件研究

猪苓的白色长菌丝在PDA培养基上能够形成厚实可剥的菌丝块。猪苓生长菌丝可形成锁状联结、顶端膨大,菌丝真径0.95～2.80um,适宜生长条件为20℃、pH4。振荡培养下,形成15～20um大小的菌丝块,颜色如潜伏其菌核的灰黄色。在6种生长原木上,猪苓形成菌丝块大小为3～5um。在PDA培养基上猪苓与蜜环菌混合培养比单独培养的菌丝粗,菌丝密度大,在原木上,猪苓菌丝与蜜环菌菌丝形成共生联结,同时在与蜜环菌紧连的菌丝块边缘,有多点状的自我防御结构。木质素降解活性检测表明,4个菌株中的A、B、C使澳酚蓝脱色后的吸光度为0.0635～0.0902,而菌株D的活性可以忽略。     

Evaluation of the management practice for controlling herbicide runoff from paddy fields using intermittent and spillover-irrigation schemes

Two water management practices, an intermittent irrigation scheme using automatic irrigation system (AI) and a spillover-irrigation scheme (SI), were compared for the fate and transport of commonly used herbicides, mefenacet (MF) and bensulfuron-methyl (BSM) in experimental paddy plots. Maximum mefenacet concentrations in paddy water were 660 and 540 μg L⁻¹ for AI and SI plot, respectively. The corresponding values for bensulfuron-methyl were 46.0 and 42.0 μg L⁻¹. Dissipation of the herbicides in paddy water appeared to follow the first-order kinetics with half-lives (DT₅₀) of 1.9–4.5 days and DT₉₀ (90% mass dissipation) of 7.8–11.3 days. The AI plot had no surface drainage, hence no herbicide was lost through paddy-water discharge. However, SI plot lost about 38 and 49% of applied mefenacet and bensulfuron-methyl, respectively. The intermittent irrigation scheme using automatic irrigation system with a high drainage gate was recommended to be a best management practice for controlling the herbicide losses from paddy fields. The paddy field managed by spillover-irrigation scheme may cause significant water and herbicide losses depending on the volume of irrigation and precipitation. The water holding period after herbicide application was suggested to be at least 10 days according to the DT₉₀ index.