The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios rangin...The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200（m/m）.Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/（mg MLVSS.hr）,respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.展开更多
目的:建立科学的宽体金线蛭种蛭筛选原则,并对产茧后药材进行质量评价。方法:从微山湖地区采集野生宽体金线蛭1193条,对体质量和生殖环带发育等群体特征进行考察。将种蛭分为10、15、20 g 3个试验组,建立卵茧成熟度观察方法以判断适宜...目的:建立科学的宽体金线蛭种蛭筛选原则,并对产茧后药材进行质量评价。方法:从微山湖地区采集野生宽体金线蛭1193条,对体质量和生殖环带发育等群体特征进行考察。将种蛭分为10、15、20 g 3个试验组,建立卵茧成熟度观察方法以判断适宜的挖茧时机,通过产茧数、茧体积、出苗数等指标考察体质量对宽体金线蛭繁殖性能的影响。依照2015年版《中华人民共和国药典》对产茧后水蛭药材的性状和抗凝血酶活性进行质量评价。结果:微山湖地区宽体金线蛭野生种群的体质量普遍较小,15 g及以上的种蛭仅占样本群体的19.53%;宽体金线蛭的繁殖性能随种蛭体质量的增加而显著提高,20 g试验组的产茧数(5.9个)和出苗数(37.3条)分别是10 g试验组的1.59倍和1.45倍。产茧后种蛭的死亡率和体质量损失率可高达37%和59%,药材厚度仅为产茧前的49%~72%,腥味散失严重、脆度下降,但产茧前后抗凝血酶活性变化不大,均为3~5 U·g^-1。结论:微山湖地区野生宽体金线蛭的种群有退化趋势,建议使用15 g及以上的种蛭进行繁殖生产。产茧后药材的商品规格和等级较低,不适宜作为饮片直接用于临床。展开更多
Fenneropenaeus chinensis is confined to the Yellow Sea and Bohai Sea in China and the West Coast of the Korean Peninsula. Intra- and in- tercross populations were produced between Rushany (YP) and Korean (KN) populati...Fenneropenaeus chinensis is confined to the Yellow Sea and Bohai Sea in China and the West Coast of the Korean Peninsula. Intra- and in- tercross populations were produced between Rushany (YP) and Korean (KN) populations. Seven traits were recorded. The heterosis of hybrids was computed and comparison between treatments was performed by ANOVA. At the fourth month after post-larvae, six indexes of growth trait and viability showed a range of heterosis, ranging from 0.514% to 14.950%. At the fifth month after post-larvae, six in- dexes of growth trait and viability ranged from -9.000% to 19.090%. The negative heterosis was observed in CL, HST and viability. The heterosis of KN♀×YP♂ tended generally to increase as the age of the Chinese shrimp increased while the heterosis of YP♀×KN♂ tended to decrease. The results indicated that the viability of reciprocal hybrids were not sig- nificantly different (P>0.05) from their parents during the experiment. The result of ANOVA indicated that the F1 hybrids were significantly different (P<0.05) in WST and TW at the fourth month. The multiple comparisons of LSD test indicated that the hybrids of YP♀×KN♂ were significantly different (P<0.05) from their parents in TW. The hybrids of YP♀×KN♂ were significantly different (P<0.05) from the other three combinations in WST. At the fifth months, the F1 hy- brids had significant difference (P<0.05) in body weight while other traits showed no significant dif-ferences (P>0.05) from their parents. The multiple comparisons of LSD test indicated that the hybrids of KN♀×YP♂ were significantly different (P<0.05) from the KN parents in TW. The results indicate that in experimental conditions, the F1 hybrids created from two populations of Chinese shrimp showed a certain level of heterosis for growth performance and viability. The crossing scheme may improve growth perform- ance and viability in Chinese shrimp, but the im- provement may be limited because effective cross- breeding requires the maintenance of pure, pref展开更多
基金supported by the National Key Technologies R&D Program of China during the Eleventh Five-year Plan Period (No. 2009BAC57B01)the State Key Laboratory of Urban Water Resource and Environment(HIT) (No. QAK201006)
文摘The effect of COD/N ratio on the granulation process and microbial population succession was investigated.Four identical sequencing batch reactors,R1,R2,R3 and R4,were operated with various initial COD/N ratios ranging from 0/200 to 800/200（m/m）.Ethanol was fed as the source of COD.Aerobic granules were successfully cultivated in R2 and R3,operating with the COD/N ratio of 200/200 and 400/200,respectively.Scanning electron microscope observations indicated that short rod-shaped and spherical bacteria were dominant in R2,while granules produced in R3 were surrounded with a large amount of filamentous bacteria.The average specific nitritation rate in R2 and R3 were 0.019 and 0.008 mg N/（mg MLVSS.hr）,respectively.Fluorescence in situ hybridization results demonstrated that nitrifying bacteria population was enriched remarkably in R2.It indicated that nitrification ability and nitrifying bacteria population were enriched remarkably at low COD/N ratio.However,no granules were formed in R1 and R4 which might attribute to either limited or excessive extracellular polymeric substances production.This study contributed to a better understanding of the role of COD/N ratio in nitrifying sludge granulation.
文摘Fenneropenaeus chinensis is confined to the Yellow Sea and Bohai Sea in China and the West Coast of the Korean Peninsula. Intra- and in- tercross populations were produced between Rushany (YP) and Korean (KN) populations. Seven traits were recorded. The heterosis of hybrids was computed and comparison between treatments was performed by ANOVA. At the fourth month after post-larvae, six indexes of growth trait and viability showed a range of heterosis, ranging from 0.514% to 14.950%. At the fifth month after post-larvae, six in- dexes of growth trait and viability ranged from -9.000% to 19.090%. The negative heterosis was observed in CL, HST and viability. The heterosis of KN♀×YP♂ tended generally to increase as the age of the Chinese shrimp increased while the heterosis of YP♀×KN♂ tended to decrease. The results indicated that the viability of reciprocal hybrids were not sig- nificantly different (P>0.05) from their parents during the experiment. The result of ANOVA indicated that the F1 hybrids were significantly different (P<0.05) in WST and TW at the fourth month. The multiple comparisons of LSD test indicated that the hybrids of YP♀×KN♂ were significantly different (P<0.05) from their parents in TW. The hybrids of YP♀×KN♂ were significantly different (P<0.05) from the other three combinations in WST. At the fifth months, the F1 hy- brids had significant difference (P<0.05) in body weight while other traits showed no significant dif-ferences (P>0.05) from their parents. The multiple comparisons of LSD test indicated that the hybrids of KN♀×YP♂ were significantly different (P<0.05) from the KN parents in TW. The results indicate that in experimental conditions, the F1 hybrids created from two populations of Chinese shrimp showed a certain level of heterosis for growth performance and viability. The crossing scheme may improve growth perform- ance and viability in Chinese shrimp, but the im- provement may be limited because effective cross- breeding requires the maintenance of pure, pref
