Mao Yuze

EFFECT OF MARINE ACIDIFICATION ON CALCIFICATION AND RESPIRATION OF CHLAMYS FARRERI

ABSTRACT Marine acidification will be an important environmental problem in the near future as a result of persistent emissions of CO2 and dissolution into seawater. In this study, we found that calcification and respiration of the Zhikong scallop (Chlamys farreri) are likely to be severely affected by increasing acidification. Calcification and respiration significantly declined as pH decreased. The calcification rate decreased by 33% when the pH of water was 7.9 compared with a pH of 8.1, and decreased close to 0 when the pH was reduced to 7.3. CO2 and O2 respiratory rates were reduced by 14% and 11%, respectively, when pH decreased from 7.9 to 7.3. Increasing acidification also led to changes in the metabolic pathways of C. farreri. Under acidic conditions, proteins may replace carbohydrates as the metabolic substrate. The survival of C. farreri is likely to be severely threatened in the next few centuries.

魁蚶 C 型凝集素基因 cDNA 的克隆及表达分析

通过cDNA末端快速扩增(Rapid amplification of cDNA ends，RACE)技术克隆得到魁蚶(Scapharca broughtonii) C型凝集素(C-type lectin，Sb-Lec1)基因，该基因全长为700 bp，其中，5′-UTR为29 bp，3′-UTR为167 bp，开放阅读框长度为504 bp，编码167个氨基酸，包括长度为23个氨基酸的信号肽序列、129个氨基酸的糖识别结构域(CRD)以及参与二硫键形成的6个半胱氨酸。预测蛋白分子量为19.11 kDa，理论等电点为4.74。多序列比对结果显示，Sb-Lec1基因CRD编码的氨基酸序列与长牡蛎(Crassostrea gigas)、紫贻贝(Mytilus galloprovincialis)和海湾扇贝(Argopecten irradians) C型凝集素的同源性分别为38%~40%、34%~35%和38%~39%，Sb-Lec1基因编码的氨基酸序列与其他物种的凝集素基因具有相似的结构，均含有形成二硫键的4个保守半胱氨酸。系统进化分析结果显示，魁蚶先与贝类聚为一支，再与脊椎动物聚在一起，表明魁蚶Sb-Lec1基因在进化树上的位置与其传统分类所处位置一致。采用荧光定量PCR技术，检测了Sb-Lec1基因在组织中的表达情况，发现其在肝胰腺、血淋巴、鳃、外套膜、闭壳肌、斧足中均有表达，其中，肝胰腺表达量最高。同时，分析了Sb-Lec1基因在鳗弧菌(Vibrio anguillarum)刺激下的mRNA表达量变化情况。结果显示，与对照组相比，菌刺激组Sb-Lec1基因mRNA在各检测组织中的表达量均显著上调(P < 0.05)，随着刺激时间的延长，表达量呈先升高后降低的趋势。本研究表明，魁蚶Sb-Lec1基因在机体免疫防御方面发挥重要功能。

牡蛎壳粉缓释剂对魁蚶( Scapharca broughtonii )生长的影响

2015年4月6日—10月26日，在桑沟湾海区现场研究了牡蛎壳粉缓释剂(Careshell)对魁蚶(Scapharca broughtonii)生长和存活的影响。按照缓释剂的重量比设置4个处理组，其中，魁蚶的初始体重均为160 g/组，缓释剂的重量分别为0(对照组C0)、80 g(C1组)、160 g(C2组)和320 g(C3组)。实验共进行200 d，每40 d测量各实验组魁蚶的生长参数(壳长、壳宽、壳高、湿重)，计录死亡个体数，计算不同阶段(40 d间隔)魁蚶的特定生长率(SGR)及死亡率。结果显示，C3组魁蚶各生长参数显著高于C0组(P 0.05)。经过200 d的养殖实验，C3组壳长、壳宽、壳高和湿重的特定生长率分别为(0.34±0.01)%/d、(0.46±0.02)%/d、(0.39±0.01)%/d、(1.11±0.002)%/d，均极显著高于C0组(P 0.05)。

Effect of mariculture activities on bacterial community structure in the water of Sanggou Bay

We evaluated the bacterial community structure in water collected from several mariculture zones in Sanggou Bay in summer 2007 using PCR-DGGE.Some of the bands were shared by two or more stations,while others were unique to a particular location.Based on the DGGE profiles,we distinguished four areas,including a no-culture area(outer bay),kelp farming area(bay-mouth),integrated mariculture area(majority of the area in the middle of the bay),and a mollusk monoculture or fish farming area(bottom of the bay).The highest similarity in the bacterial community structure was between the scallop and oyster culture areas(94%),while the lowest was between the no-culture and mollusk monoculture or fish farming area(41%).Sequence analysis of twelve major bands from the DGGE profiles revealed that these sequences were highly similar to those of Actinobacteria,Firmicutes,and Proteobacteria,including class Alpha and Gamma proteobacteria.The similarity of the nucleotide sequences ranged from 92% to 98%.Roseobacter,which can remove nitrogen-containing pollutants,was only present in the fish farming area.Our results suggest that seaweed culture had a lower impact on the environment then shellfish monoculture and fish culture.Thus practicing IMTA can reduce the degree of pollution from shellfish and fish monoculture.