摄食不同淀粉含量饲料对军曹鱼血清生化指标的影响

实验旨在研究经过10周投喂不同淀粉含量的饲料的养殖实验后, 禁食1d后再投喂对170 g军曹鱼血清生化指标的影响. 饲料以鱼粉为蛋白源, 鱼油、豆油、大豆卵磷脂为脂肪源, 分别添加0%(对照组)、6%、12%、18%、24%和30%的小麦淀粉(以微晶纤维素调平), 养殖实验期间每天饱食投喂2次. 结果表明, 饥饿再投喂饲料后各处理组军曹鱼血糖含量均在(0-5)h升高, 在5h时达到峰值, 并显著高于其他时间组, 摄食5h后开始下降, 7h时基本恢复到投喂前水平; 血清总蛋白含量在不同处理组以及同一处理组的不同时间点上均没有显著差异; 血清中甘油三酯含量在(0-5)h显著升高, 5h后其含量开始下降, 7h时基本恢复到投喂前水平. 其中0%、6%和12%组, 摄食5h后其甘油三酯含量显著高于摄食前与摄食后7h和24h, 而在18%、24%和30%组中, 其含量无显著差异; 0%淀粉组血清中胆固醇含量在(0-2)h显著升高, 2h时达到峰值, 在(2-7)h呈下降趋势, 之后趋于平稳. 其他处理组都是在(0-5)h升高, 5h后开始下降, 在7h时基本恢复到投喂前水平. 18%-30%组, 摄食后5h血清中胆固醇含量显著高于摄食前与摄食后24h. 军曹鱼血清中低密度脂蛋白-胆固醇在(0-5)h显著升高, 摄食5h后其含量开始下降, 7h时基本恢复到投喂前水平, 但各组不同时间点间均无显著性差异. 而血清中高密度脂蛋白-胆固醇含量除在24%添加组中, 摄食后5h显著高于摄食前(0h)及投喂结束后24h处理组, 其他处理之间无显著差异. 综上所述: 170 g军曹鱼禁食再摄入不同含量的小麦淀粉后其血清中血糖含量先升高后降低, 随着饲料中糖添加量的增加, 其峰值先增加, 后趋于平稳. 军曹鱼血清甘油三酯和胆固醇的含量会升高, 对其血清中低密度脂蛋白-胆固醇及高密度脂蛋白-胆固醇影响不显著.       

光照对蒙古裸腹溞摄食强度的影响

利用细胞计数法对不同光照强度、光谱成分、光周期对蒙古裸腹摄食强度的影响进行了研究。结果表明 :光强在 70 0 0 lx时蒙古裸腹对小球藻的摄食强度最高 ,成的滤水率和摄食率分别为 0 .5 2 8± 0 .0 0 9ml/ (ind· h)和 1.113± 0 .0 15μg C/ (ind· h) ,幼的滤水率分别为 0 .4 95± 0 .0 14 ml/ (ind· h)和 1.0 5 1± 0 .0 0 8μg C/ (ind· h)。在蓝光下蒙古裸腹对小球藻的摄食强度明显高于绿光组。光周期 L∶ D为 12∶ 12时蒙古裸腹对小球藻的摄食强度最高 ,成和幼的滤水率分别为0 .4 6 1和 0 .35 5 ml/ (ind· h) ,摄食率分别为 1.2 4 2和 1.0 0 5μg C/ (ind· h) ,而在 L∶ D为 0 :2 4时摄食强度最差 ,成和幼的滤水率分别为 0 .0 70和 0 .0 5 0 ml/ (ind· h)。在自然光照下 ,蒙古裸腹对小球藻的摄食强度在 7∶ 0 0～ 11:0 0和 15 :0 0～ 19:0 0最高     

饥饿对食蚊鱼仔鱼摄食、生长和形态的影响

本文研究了饥饿胁迫下食蚊鱼仔鱼的摄食、生长和外部形态的变化规律.结果表明,在水温(28.5±1.2)℃时,仔鱼产出2h后鳔完成充气即建立巡游模式并开始觅食,摄食比率迅速达到100%,其混合营养期仅有4h.实验期间,投喂组仔鱼的摄食比率一直保持在100%;饥饿组仔鱼在饥饿0-3d内初次摄食比率同样可达到或接近100%,但第4天开始下降,第6天初次摄食比率降至0,抵达饥饿不可逆点(PNR)时间为产出后第5.5天左右.投喂组初产仔鱼对1-2龄期库蚊幼虫的摄食强度为(2.9±1.4)ind/individual·h,摄食强度随日龄显著增长;饥饿组仔鱼在饥饿0-5d内其初次摄食强度也随日龄及饥饿时间的延长显著增长,但均显著低于相应日龄的投喂组仔鱼,其初次摄食比率与初次摄食强度之间并无显著相关关系.饥饿仔鱼在PNR前约1.5d时其累计死亡率已超半数,达(64.4±18.1)%,抵达PNR后数小时内残存个体全部死亡.实验结束(6d)时投喂组仔鱼5项生长指标呈不等速增长,其中体重增长最为显著,瞬时增长率达0.0275/d,此时腹鳍发育基本完备,进入幼鱼期.而同期饥饿组仔鱼形态发育停滞,多项生长指标出现负增长,其中体高负增长最为明显,其瞬时增长率为-0.0511/d;体重次之,体长负增长则不甚明显.饥饿仔鱼在接近或处在PNR期时腹部萎缩呈弧形,体长/体高>5,而同期投喂组仔鱼体长/体高<4.5,两者差异显著,可作为鉴别饥饿仔鱼和健康仔鱼较理想的形态数量指标.     

丙氨酰-谷氨酰胺投喂方式对建鲤生长、抗氧化及免疫力的影响

以初始质量为(33.52±0.17)g建鲤鱼种为研究对象,在室内单循环养殖系统中进行8周(w)生长试验,分别配制添加0.0%(对照饲料)和0.5%(试验饲料)丙氨酰-谷氨酰胺(Ala-Gln)的等氮(35 g/kg粗蛋白)、等能(17kJ/g能量)饲料,采用5种不同的Ala-Gln投喂方式[连续8w投喂对照饲料(I,对照组);试验饲料2w交替投喂(II);前4w投喂试验饲料、后4w投喂对照饲料(III);前4w投喂对照饲料、后4w投喂试验饲料(IV);8w连续投喂试验饲料(V)],探讨Ala-Gln投喂方式对建鲤生长、抗氧化及免疫力的影响。结果表明:Ala-Gln连续投喂和不连续投喂的生长都显著高于对照组(P<0.05)。2w交替投喂的生长率显著高于4w交替和连续8w投喂试验饲料组(P<0.05),前4w投喂试验饲料且后4w投喂对照饲料的生长率要高于8w连续投喂试验饲料组(P<0.05)。后4w投喂试验饲料组和连续8w投喂试验饲料组的血清SOD显著高于对照组(P<0.05);连续8w投喂试验饲料组显著高于2w交替投喂试验饲料组和前4w投喂试验饲料组的血清SOD(P<0.05)。Ala-Gln各种投喂方式组的肝胰脏谷胱甘肽过氧化物酶(GSH-Px)都显著高于对照组(P<0.05)。后4w投喂试验饲料组和连续8w投喂试验饲料组的血清GSH-Px显著高于对照组(P<0.05)。在Ala-Gln四种投喂方式组中,除2w交替投喂组外,其他三种投喂方式组的头肾LZM都显著高于对照组(P<0.05)。后4w投喂试验饲料组和8w连续投喂试验饲料组的脾脏LZM都显著高于对照组(P<0.05)。对照组头肾NO要显著高于各投喂方式组(P<0.05)。在试验条件下,饲料中添加Ala-Gln可提高建鲤的生长、抗氧化和免疫力。不同投喂方式间亦有显著差异,从生长、抗氧化和免疫的角度,结合经济性和适用性等进行考虑,建议采用2w间隔投喂的方式。     

北朱雀、燕雀和白腰朱顶雀的能量代谢特征和体温调节

本实验采用封闭式流体压力呼吸计 ,测定了环境温度在 5 - 34℃范围内北朱雀 (Carpodacusroseus)、燕雀 (Fringillamontifringilla)和白腰朱顶雀 (Acanthisflammea)的耗氧量、热传导、体温等指标 ,探讨了其代谢产热特征。结果表明 :在环境温度 (Ta)为 5 - 30℃的范围内 ,北朱雀的体温基本维持恒定 ,平均体温为4 0 4 6± 0 1 0℃ ,热中性区为 2 2 5 - 2 7 5℃ ,基础代谢率为 4 30± 0 0 8mlO2 /(g·h) ;环境温度在 5 - 2 0℃范围内 ,代谢率 (MR)与Ta 呈负相关 ,回归方程为MR [mlO2 /(g·h) ]=9 34- 0 2 1Ta (℃ ) ;在此范围内 ,北朱雀的热传导率最低且基本保持恒定 ,平均为 0 2 4± 0 0 0mlO2 /(g·h·℃ )。在环境温度为 5 - 34℃的范围内 ,燕雀的体温基本保持稳定 ,为 4 0 4 0± 0 1 1℃ ,热中性区为 2 5 - 30℃ ,基础代谢率为 4 1 9± 0 0 5mlO2 /(g·h) ;环境温度在 5 - 2 5℃范围内 ,MR与Ta 的回归方程为 :MR [mlO2 / (g·h) ]=1 1 6 4 - 0 2 9Ta (℃ ) ;在 5- 30℃内 ,燕雀的热传导最低 ,平均为 0 2 9± 0 0 1mlO2 / (g·h·℃ )。白腰朱顶雀的热中性区为 2 5 - 2 8℃ ,平均体温为 4 0 4 8± 0 1 1℃ (5 - 34℃ ) ,最低代谢率为 4 4 5± 0 1 4mlO2 / (g·h) ,最低热传导为 0 3     

分离自象山港的15种海洋微藻脂肪酸比较研究

在160μmol.m-2.s-1光强、（20±2）℃条件下对分离自象山港的15种海洋微藻进行培养,在稳定期离心收集,冷冻干燥后用Bligh-Dyer法提取总脂,皂化衍生化后用气相色谱-质谱联用分析系统对其含有的脂肪酸进行定量和定性的分析。结果表明,这15种微藻总脂含量均较高,其中有9种微藻的总脂含量超过干重的10%,中心硅藻纲中共有的含量相对较高的主要脂肪酸为C14∶0、C16∶0、C16∶1（n-7）脂肪酸和EPA,针胞藻纲的赤潮异湾藻则含有高比例的C16∶0、C18∶4（n-3）和EPA,纵裂甲藻纲和甲藻纲中共有的含量相对较高的主要脂肪酸为C16∶0、C18∶4（n-3）、C18∶5（n-3）和DHA,而隶属于定鞭藻门颗石藻纲的颗石藻含量相对较高的主要脂肪酸分别为C16∶0、C18∶4（n-3）和DHA。这些藻是否可以作为生物饵料还需实际养殖投喂效果决定。     

人工食物对高原鼠兔稳定性碳和氮同位素组成的影响

以玉米面、小米面和绿豆粉 (质量比为 5∶3∶2 )的混合食物饲喂青藏高原地区特有种高原鼠兔 ,4 0d后断头杀死 ,取其后腿肌肉测定稳定性碳和氮同位素组成。结果表明 ,用混合食物饲喂后 ,高原鼠兔的稳定性碳同位素比值显著升高 ,由对照的 (- 2 4 6 6± 0 2 5 )‰上升为 (- 19 0 5± 0 0 9)‰ ;稳定性氮同位素的组成变化较小 ,仅由对照的 (3 2 8± 0 13)‰增加为饲喂后的 (3 6 1± 0 32 )‰。经人工食物饲喂后 ,高原鼠兔与其食物间稳定性碳同位素的分馏效应为 4 73‰ ,稳定性氮同位素的分馏效应为 2 79‰。C4组分食物的加入影响高原鼠兔的稳定性同位素 (特别是氮同位素 )代谢模式 ,其稳定性同位素代谢周转率可能高于原来预测的 4 0d。     

延迟初次投喂对太门哲罗鱼仔鱼生长和存活的影响

在水温为10.4～14.9℃条件下,研究了延迟初次投喂对太门哲罗鱼仔鱼的生长、存活和个体大小差异的影响.该试验共分5组:S0(饥饿0d,对照)、S1(开口9d后投喂)、S2(开口12 d后投喂)、S3(开口15 d后投喂)、S4(开口18d后投喂).结果表明:经过36 d试验,S1组生长率和初次摄食率高于S0组,试验结束时总体的死亡率低于S0组,两组个体大小和体质量均无显著性差异;S2组生长率和初次摄食率高于S0组,两组个体大小差异不显著,但S2组体质量明显低于S0组,且总死亡率和自残死亡率均高于S0组;S3组初次摄食率高于S0组,总死亡率、自残死亡率和个体大小均高于S0组,虽然生长率接近S0组,但体质量明显低于S0组;S4组生长率和体质量均小于S0组,总死亡率和自残死亡率高于S0组.相同条件下延迟9d投喂太门哲罗鱼仔鱼出现了“完全补偿生长”,可应用于太门哲罗鱼初次摄食期仔鱼的培育.     

投喂频率对红鳍东方鲀生长和行为的影响

以红鳍东方鲀(Takifugu rubripes)幼鱼为实验对象,研究在日投喂量相同的条件下,不同投喂频率[3次/d(F3)、4次/d(F4)和5次/d(F5)]对幼鱼生长和行为的影响。结果表明:(1) F4组幼鱼的生长性能显著高于F3和F5组(P<0.05);(2)在实验结束时,不同处理组幼鱼的游泳速度差异显著,从大到小依次为F4>F3>F5(P<0.05),F4组幼鱼的角速度显著高于F3和F5组(P<0.05), F4组幼鱼的加速度和活跃度显著低于F3和F5组(P<0.05), F3组幼鱼的对象间距离显著高于F4和F5组(P<0.05);(3) GLMMs的结果表明, F4组幼鱼的游速受到实验时间与投喂频率交互效应的影响显著(P<0.05),各处理组之间的比较结果显示,实验时间和投喂频率的交互效应对F5组幼鱼的加速度有正向效果,但其显著降低了F5组幼鱼的对象间距离。综上所述,不同投喂频率对幼鱼的生长性能和行为表现具有显著影响。实验推测4次/d的投喂频率可能改变了幼鱼的能量分配,更多的能量被用于生长和游泳,使得幼鱼的生长性能有所提高,并...     

外源激素对中华鳖胚胎期性别决定及仔稚鳖第一性征的影响

中华鳖(Trionyx sinensis)属于温度依赖型性别决定。为研究外源性17α-甲基睾酮(17α-methyltestosterone,MT)和雌二醇(estradiol,E_2)对中华鳖胚胎敏感期的性别决定及仔稚鳖第一性征的影响,本实验通过激素注入法,在胚胎性别决定敏感期,进行MT和E_2处理。结果表明:激素处理显著影响胚胎存活率; E_2组平均孵化时间比对照组提前5.5 d,MT组平均孵化时间稍晚于对照组; E_2组全为雌鳖,MT组全为雄鳖,对照组的雌雄比例为3∶11;给驯养20 d后的稚鳖投喂40 d拌有不同浓度MT和E_2的饲料,设置25、50和100mg·kg-1三个处理组和对照组;激素处理对仔稚鳖的存活率无显著影响,对其形态发育具有一定的促进作用;投喂40 d后,50 mg·kg-1处理E_2组的性别比例(雄性只数∶性别待定只数∶雌性只数)由19∶6∶15变为19∶0∶4,最终雌性比例(17. 39%)与对照组(16.67%)无显著差异,25 mg·kg-1处理E_2组与100 mg·kg~(-1)处理E_2组的雌性比例为0,MT各处理组性别比例(雄性只数∶性别待定只数∶雌性只数)分别为9∶0∶0、19∶0∶0和8∶0∶0,全为雄性群体,第一性征较E_2组和对照组更加明显。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.