Development of a water quality index model for lakes and reservoirs

Lake water quality and trophic state are evaluated using various parameters which may have different interpretations. Therefore, it is useful to adopt a proxy index that shows normalized values of parameters having different units and distribution characteristics. In this study, a model for integrated water quality index was developed for lakes and reservoirs in Korea. Water quality and phytoplankton were examined in 36 lakes, two natural lakes and 34 artificial lakes. The study lakes were selected to represent the range geographic regions and lake morphology in Korea. After investigating the interrelationships among water quality parameters, four parameters (total organic carbon, chlorophyll-a, total phosphorus, and turbidity) were selected as surrogate indicators of overall water quality. A relative evaluation system was developed by adopting a logistic function index that describes a cumulative distribution function and reflects the relative position of each parameter among the study lakes. The cumulative distribution probability ranging from 0 to 1 was multiplied by 100 and then transformed into the Korean Lake Water Quality Index (LQI) ranging from 0 to 100. A score of 50 was assigned to the median value of the dataset, 0 to the highest concentration value and 100 to the lowest concentration value. Thus, the LQI is an integrated easy-to-understand index that provides information about the relative status of each lake. The results of this study can represent a model to provide a relative evaluation system for lake and reservoir water quality, which can be useful for ecosystem management within an ecoregion or a jurisdictional district.     

Assessing the effect of watershed slopes on recharge/baseflow and soil erosion

Aquatic ecosystems are threatened by increasing variability in the hydrologic responses. In particular, the health of river ecosystems in steeply sloping watersheds is aggravated due to soil erosion and stream depletion during dry periods. This study suggested and assessed a method to improve the adaptation ability of a river system in a steep watershed. For this, this study calibrated soil and water assessment tool (SWAT) for runoff and sediment, and quantified the changes in hydrologic responses such as groundwater recharge rate soil erosion and baseflow according to two scenarios for adjustment of the watershed slope (steep to mild). Here, one scenario was set by three measured slopes, and the other was set by fixing the entire watershed slopes with 5 %. Moreover, SWAT and web-based hydrograph analysis tool (WHAT) models were applied to estimate groundwater recharge, soil erosion, and baseflow in the Haean-myeon watershed in South Korea. The results show that the reduction of watershed slope increased groundwater recharge and baseflow, and decreased sediment. Specifically, groundwater recharge rate was increased from 257.10 to 364.60 mm, baseflow was increased from 0.86 to 1.19 m³/s, and sediment was decreased from 194.6 to 58.1 kg/km². Based on these results, the suggested method will positively contribute to aquatic ecosystems and farming environments in a steeply sloping watershed due to improvements in the quantity and quality of river water.     

LDL-antioxidant pterocarpans from roots of Glycine max (L.) Merr

The methanolic root extract of Glycine max (L.) Merr. was chromatographed, which yielded 10 flavonoids, including three isoflavones 1-3, five pterocarpans 4-8, one flavonol 9, and one anthocyanidin 10. All isolated compounds were examined for LDL-antioxidant activities using four different assay systems on the basis of Cu2+-mediated oxidation. Among them, seven compounds showed potent LDL-antioxidant activities in the thiobarbituric acid reactive substances (TBARS) assay, the lag time of conjugated diene formation, relative electrophoretic mobility (REM), and fragmentation of apoB-100 on copper-mediated LDL oxidation. Three pterocarpans 4, 6, and 7, never reported as LDL-antioxidant, showed potent activities with IC50 values of 19.8, 0.9, 45.0 microM, respectively, in comparison with probucol (IC50 = 5.6 microM) as positive control. Interestingly, coumestrol 6 (IC50 = 0.9 microM) showed 20 times more activity in the TBARS assay than genistein (IC50 = 30.1 microM) and daidzein (IC50 = 21.6 microM), representative antioxidants in soybean. Moreover, coumestrol 6 had an extended lag time of 190 min at 3.0 microM in measuring conjugated diene formation, while both genistein (120 min) and daidzein (93 min) lag times were extended to less than 120 min at the same concentration.     

Isolation and antifungal and antioomycete activities of staurosporine from Streptomyces roseoflavus strain LS-A24

The actinomycete strain LS-A24 active against some plant fungal and oomycete pathogens was isolated from a soil sample of the Sunghwan Lake in Korea. The cell wall composition and spore shape of strain LS-A24 were LL-diaminopimelic acid and spiral type, respectively. On the basis of the physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, strain LS-A24 was identical to Streptomyces roseoflavus. An antifungal and antioomycete antibiotic was isolated from LS-A24 using various chromatographic procedures. The molecular formular of the antibiotic was determined to be C(28)H(26)N(4)O(3), and on the basis of the NMR data, the antibiotic was confirmed to be staurosporine, 2,3,10,11,12,13-hexahydro-10R-methoxy-9S-methyl-11R-methylamino-9S,13R-epoxy-1H,9H-diindolo[1,2,3-gh:3',2',1'-lm]pyrrolo[3,4-j][1,7]benzodiazonin-1-one. Staurosporine completely inhibited the mycelial growth of Colletotrichum orbiculare, Phytophthora capsici, Rhizoctonia solani, Botrytis cinerea, and Cladosporium cucumerinum with minimum inhibitory concentration (MIC) values of 1-50 microg/mL for MICs. Staurosporine also was active against Saccharomyces cerevisiae, Bacillus subtilis ssp. subtilis, and Xanthomonas vesicatoria. Staurosporine and the commercial fungicide metalaxyl inhibited the development of Phytophthora blight on pepper plants. However, the control efficacy of staurosporine against the Phytophthora disease was somewhat less than that of metalaxyl. This is the first study to isolate staurosporine from S. roseoflavus and demonstrate its in vitro and in vivo antioomycete activity against P. capsici.     

The effects of transplacental porcine circovirus type 2 infection on porcine epidemic diarrhoea virus-induced enteritis in preweaning piglets

The effects of transplacental porcine circovirus type 2 (PCV2) infection on porcine epidemic diarrhoea virus (PEDV)-induced enteritis were examined in neonatal piglets. Six pregnant sows were randomly allocated to an infected (n=3) or control group (n=3). Three pregnant sows were inoculated intranasally with 6 mL of tissue culture fluid containing 1.2 x 10(5) tissue culture infective doses 50% (TCID(50))/mL of PCV2 strain SNUVR000470 three weeks before the expected farrowing date. Three control pregnant sows were similarly exposed to uninfected cell culture supernatants. Thirty piglets from PCV2-infected sows were randomly assigned to two groups (A and B) of 15 piglets each. Another 30 piglets from noninfected sows were randomly assigned to two groups (C and D) of 15 piglets each. The piglets in groups A and C were dosed orally at three days of age with 2mL of virus stock (1 x 10(6.5) TCID(50)/mL) of the PEDV strain, SNUVR971496, at the third passage. The mean villous height and crypt depth (VH:CD) ratio in PEDV-infected piglets from PCV2-infected sows (group A) were significantly different from those of the PEDV-infected piglets from PCV2 negative sows (group C) at 36, 48, and 72 h post-inoculation (hpi) (P<0.05). In PEDV-infected piglets from PCV2-infected sows (group A), significantly more PEDV nucleic acid was detected in the jejunal tissues (P<0.05) at 24 hpi than in the same tissues of the PEDV-infected piglets from PCV2 negative sows (group C). Thereafter, at 36, 48, 60, and 70 hpi significantly more PEDV nucleic acid (P<0.05) was detected in the jejunal tissues of the PEDV-infected piglets from PCV2 negative sows (group C) than those of the PEDV-infected piglets from the PCV2-infected sows (group A). It is concluded that the clinical course of PEDV disease was markedly affected by transplacental infection of PCV2.     

IMAGING DIAGNOSIS—A LUMINAL LAMINATED DEBRIS BALL IN THE URINARY BLADDER OF A DOG

A 5‐year‐old dog presented with pollakiuria and urinary incontinence. Abdominal radiographs revealed an oval, multilayered structure with soft tissue opacity and gas lucency in the urinary bladder. Ultrasonography showed an oval luminal structure with hyper‐ and hypoechoic layers and internal reverberation artifacts. Following cystotomy, the hemisected plane showed a layered, pale whitish matrix with a gas layer around the core. Histopathological examination showed no evidence of cells, bacteria, or fungi. The core and laminae comprised fibrinous and mineral debris. A final diagnosis of a freely floating, gas‐filled laminated debris ball was made.     

Sequence variation in the bolting time regulator BTC1 changes the life cycle regime in sugar beet

In beet production, flowering is an undesirable trait which drastically reduces yield. BOLTING TIME CONTROL 1 (BTC1) and BvBBX19 are major floral regulators in beet. Their proteins have been suggested to interact to jointly regulate their downstream targets BvFT1 and BvFT2. Annual and biennial BTC1 haplotypes differ by six non‐synonymous SNPs and a large insertion in the promoter of the biennial btc1 allele. We describe a new BTC1 allele which displays three nucleotide polymorphisms in the coding sequence and an 8‐bp insertion in the promoter region compared to the annual BTC1_d allele. The protein lacks a low‐complexity region, which likely alters its suggested ability to bind BvBBX19. Our findings demonstrate that little sequence variation in BTC1 is sufficient to turn an annual into a biennial genotype. Our results shed new light on the evolution of cultivated beets, and the identified btc1_l allele offers new possibilities to breed winter beets.     

复合益生素对生长育肥猪生产性能、盲肠菌群及代谢产物的影响

试验旨在研究饲粮中添加复合益生素(JS菌)对生长育肥猪生产性能、盲肠菌群、挥发性脂肪酸及蛋白质腐败产物的影响。试验选择120头体重10 kg左右的健康DLY仔猪,随机分为对照组、抗生素组、0.1%JS菌组和0.2%JS菌组,每组5个重复。结果表明:与对照组相比,添加0.2%JS菌显著提高试猪30~50 kg阶段的平均日增重和采食量(P0.05);添加0.1%JS菌显著提高试猪80~100 kg阶段的平均日增重(P0.05);从试验全期来看,抗生素组、0.1%JS菌组和0.2%JS菌组试猪平均日增重和采食量均有所提高,但各组间差异不显著(P0.05)。添加JS菌趋于增加盲肠内容物乳酸杆菌数量,减少大肠杆菌数量(P0.05),从而提高二者的比值,分析PCR-DGGE图谱发现添加JS菌对菌群多样性和相似性也有一定影响。与对照组相比,0.1%JS菌组和0.2%JS菌组盲肠内容物乙酸含量分别提高2.35倍和2.99倍,丁酸含量分别提高58.87%和62.10%,挥发性盐基氮含量分别降低31.91%和28.53%(P0.05)。在本试验条件下,添加JS菌对生长育肥猪的生产性能有一定改善,效果与抗生素基本相当,这可能与其对肠道健康的保护作用有关。