High yield and rapid growth of Neoparamoeba pemaquidensis in co-culture with a rainbow trout gill-derived cell line RTgill-W1

Neoparamoeba pemaquidensis is an ubiquitous amphizoic marine protozoan and has been implicated as the causative agent for several diseases in marine organisms, most notably amoebic gill disease (AGD) in Atlantic salmon. Despite several reports on the pathology of AGD, relatively little is known about the protozoan and its relationship to host cells. In this study, an in vitro approach using monolayers of a rainbow trout gill cell line (RTgill-W1, ATCC CRL-2523) was used to rapidly grow large numbers of N. pemaquidensis (ATCC 50172) and investigate cell-pathogen interactions. Established cell lines derived from other tissues of rainbow trout and other fish species were also evaluated for amoeba growth support. The amoebae showed preference and highest yield when grown with RTgill-W1 over nine other tested fish cell lines. Amoeba yields could reach as high as 5 x 10(5) cells mL(-1) within 3 days of growth on the gill cell monolayers. The amoebae caused visible focal lesions in RTgill-W1 monolayers within 24 h of exposure and rapidly proliferated and spread with cytopathic effects destroying the neighbouring pavement-like cells within 48-72 h after initial exposure in media above 700 mOsm kg(-1). Disruption of the integrity of the gill cell monolayers could be noted within 30 min of exposure to the amoeba suspensions by changes in transepithelial resistance (TER) compared with control cell monolayers maintained in the exposure media. This was significantly different by 2 h (P < 0.05) compared with control cells and remained significantly different (P < 0.01) for the remaining 72 h that the TER was monitored. The RTgill-W1 cell line is thus a convenient model for growing N. pemaquidensis and for studying host-pathogen interactions in AGD.     

天津重点水域底栖生物调查分析

于2018年9月,对天津大港,宝坻,华苑等地区的12个站点的大型底栖生物的群落结构及生物多样性进行了调查分析。结果表明,调查区共鉴定出大型底栖生物3门10种,其中软体动物4种,环节动物4种,水生昆虫2种,各站位丰度波动范围为20～840 ind/m^2,平均为205.33 ind/m^2,生物量范围为0.012～308.63 g/m^2,平均为59.69 g/m^2;囊螺为该地区绝对优势种。丰富度指数Margalefs.index在1.48～3.334之间波动, Goodnight修正指数在0.523～1之间波动。     

以法兴渔、促进渔业又好又快发展——就《河北省渔业条例》实施采访河北省农业厅副厅长、河北省水产局局长王进

为加强渔业资源保护、增殖、开发和合理利用,维护渔业生产者的合法权益,保障渔业生产安全和水产品质量安全,促进渔业发展,经修订后的《河北省渔业条例》,于2007年11月23日省十届人大常委会第三十一次会议审议通过,2008年1月1日起施行。     

Effects of different dietary copper sources on the growth and intestinal microbial communities of Pacific white shrimp (Litopenaeus vannamei)

An 8‐week feeding trial was conducted to evaluate the effects of dietary copper sources on growth performance and intestinal microbial communities of juvenile Pacific white shrimp (Litopenaeus vannamei). Four isonitrogenous (420 g/kg crude protein) and isolipidic (70 g/kg crude lipid) experimental diets were formulated to contain different copper sources, Diet NSC (no‐supplemented copper), Diet CS (copper sulphate), Diet Availa (copper amino acid complex from Availa^®Cu100) and Diet M (1:1, copper sulphate + copper amino acid complex). A total of 360 Pacific white shrimp juveniles (initial weight: 1.86 ± 0.03 g) were randomly allocated into four groups, with three replicates per group and 30 shrimps each replicate. An Illumina‐based sequencing method was used to analyse the intestinal bacterial composition of shrimp juveniles. The results revealed that shrimps fed Diet M had significantly higher percent weight gain (PWG) than that fed Diet NSC and Diet CS, while there were no significant differences between Diet M and Diet Availa. Survival was not affected by the dietary copper sources. Proteobacteria and Bacteroidetes were dominant in the intestines of Pacific white shrimp. Shrimps fed Diet M and Diet Availa had higher bacterial richness and diversity than those fed Diet NSC and Diet CS with no significant differences among all treatments. Furthermore, Diet M and Diet Availa which contained copper amino acid complex reduced the relative abundance of Vibrionaceae in shrimp intestinal tract. This study indicated that dietary copper sources could affect the intestinal microbial communities and diets supplemented with Availa^®Cu100 could have a positive impact on the growth performance and decrease the potential risk of disease in Pacific white shrimp.     

Changes in thyroid hormone levels in eggs and larvae and in iodide uptake by eggs of coho and chinook salmon,Oncorhynchus kisutsch andO. tschawytscha

Developmental profiles of thyroxin (T₄), triiodothyronine (T₃) and radioactive iodide uptake were established for eggs and T₄ and T₃ profiles were established for larvae (whole-body, yolk-only and body-only) of coho and chinook salmon. T₄ and T₃ were consistently present in all samples. In eggs, hormone levels remained fairly constant in all cohorst for at least the first three weeks of incubation, but then fluctuated in both directions in some sample groups. Large increases in T₄ (from 9 ng/g to 245 ng/g) were seen in 1985 chinook eggs 28 days after fertilization. Radioactive iodide uptake (which was used as a possible indicator of thyroxinogenesis) increased at least 10-fold in both 1986 coho and chinook eggs from 23–30 days after fertilization. T₄ (62 ng/g) and T₃ (393 ng/g) were found in the bodies of 28-day-old 1986 chinook embryos. In whole larvae, hormone levels varied depending upon the cohort studied. In general, initial body-only concentrations of both T₄ and T₃ decreased as body weight increased, but before yolksac resorption was completed, both thyroid hormone content and concentration increased (except for chinook T₃). T₄ and T₃ content in larval yolk stayed constant as yolksac size decreased, resulting in increased thyroid hormone concentration in the yolksac. All of these data suggest that the initial source of thyroid hormones in coho and chinook salmon eggs is maternal, but that by approximately 3–4 weeks after fertilization, the developing embryos begin to produce their own thyroid hormones. After hatching, increases in tissue T₄ and T₃ concentration coupled with constant T₄ and T₃ content in diminishing yolksacs suggest that larvae also produce their own thyroid hormones; yolksac content then may reflect both the original maternal hormones and the larva-producted hormones.     

Isolation and characteristics of eight novel polymorphic microsatellite loci from the genome of garlic (Allium sativum L.)

Here we characterized eight novel polymorphic SSR markers, developed from an enriched genomic library of garlic (Allium sativum L.). These SSRs produced a total of 64 alleles across 90 garlic accessions, with an average of 8 alleles per locus. Values for observed (H_O) and expected (H_E) heterozygosity ranged from 0.16 to 0.77 (mean = 0.44) and from 0.22 to 0.86 (mean = 0.65), respectively. Six loci deviated significantly (P < 0.05) from Hardy–Weinberg equilibrium (HWE). The averages of gene diversity and PIC values were 0.65 and 0.62, respectively. The mean genetic similarity coefficient was 0.4380, indicating that among garlic accessions existed wide genetic variation. Based on 64 alleles obtained by 8 SSRs, a phenogram was constructed to understand the relationships among the 90 accessions. These newly developed SSRs should prove very useful tools for genotypes identification, assessment of genetic diversity and population structure in garlic.     

Effect of inhibiting nuclear factor-kappa B on TNF-α-induced expression of angiotensinogen and production of angiotensinⅡ in glomerular mesangial cells

AIM: To study the effect of inhibiting nuclear factor-kappa B (NF-κB) activity on the expression of angiotensinogen (AGT) and the production of angiotensinⅡ (AngⅡ) induced by tumor necrosis factor-α (TNF-α) in glomerular mesangial cells (MCs) of SD rats. METHODS: The MCs of SD rats were isolated and divided into three groups as follows: control; MCs treated with TNF-α, and the MCs treated with TNF-α + pyrrolidinedithiocarbamate (PDTC). The activity of nuclear factor-kappa B was measured by electrophoretic mobility shift assay. The expression of AGT was determined by RT-PCR for mRNA and Western blotting for protein. The concentration of angiotensinⅡ in supernatant was measured by RIA. RESULTS: The NF-κB activity in the MCs treated with TNF-α (20.67±9.14)×102 μg/cell was significantly higher than that in control cells ［(8.25±4.35)×102 μg/cell, P<0.01］ and the MCs treated with TNF-α+PDTC ［(7.20±4.57)×102 μg/cell, P<0.01］, and no significant difference was found between control and the MCs treated with TNF-α＋PDTC (P>0.05). The AGT mRNA level in the MCs treated with TNF-α (0.27±0.05) was higher than that in the control cells (0.20±0.05, P<0.05), and no significant difference was observed when compared with that in the MCs treated with TNF-α＋PDTC (0.22±0.06, P>0.05). The expression of AGT protein in the MCs treated with TNF-α (0.60±0.19) μg/cell was higher than that in the control ［(0.37±0.15)μg/cell, P＜0.05］ and the MCs treated with TNF-α＋PDTC ［(0.37±0.17)μg/cell, P<0.05］, and no significance was found between the MCs treated TNF-α＋PDTC and the control (P>0.05). The AngⅡ level in supernatant of cultured MCs treated with TNF-α ［(9.73±2.38)×10-5 ng·L-1/cell］ was significantly higher than that in the control ［(7.50±1.51)×10-5 ng·L-1/cell, P<0.05］ and in the MCs treated with TNF-α＋PDTC ［(6.94±1.46)×10-5 ng·L-1/cell, P<0.05］, however, the difference between the MCs treated with TNF-α＋PDTC and the control was of no significance (P>0.05). CONCLUSION: TNF-α activates the NF-κB in glomerular MCs, induces the AGT expression and the production of AngⅡ. Inhibition of NF-κB decreases the AGT expression and the production of AngⅡ. Therefore, the effects of TNF-α on AGT and AngⅡ may be mediated by NF-κB.     

2BYS—6型水田中耕除草机设计与试验

简述了2BYS-6型水田中耕除草机的结构、工作原理及关键部件的设计,对该机旋转除草和摆动除草两种工作部件运动作了理论分析.田间试验结果表明:该机用于机插秧水稻田除草行间杂草平均除净率(相对除净率)78.1%,中耕深度4.39 cm,作物损伤率不大于6.89%.     

黄糊精/秸秆纤维复合材料弯曲性能分

利用模压方法制备了黄糊精/秸秆纤维复合材料,并利用试验方法研究黄糊精/秸秆纤维复合材料的弯曲性能.研究结果表明:在试验条件下,通过对黄糊精/秸秆纤维复合材料弯曲强度和弯曲弹性模量的极差分析发现最优组合相同,即热压温度A=170℃、热压压力B=9.8 MPa、热压时间C=20 min、黄糊精质量D=30 g,并对最优组合进行了试验验证,得出其弯曲强度为15.34 MPa,弯曲弹性模量为2 522.78 MPa.通过对复合材料的弯曲强度和弯曲弹性模量的方差分析发现,热压时间是不显著因素,而热压压力是显著因素.