微囊藻细胞抽提液对小鼠血液的亚慢性毒性

本文研究了注射含微囊藻毒素的微囊藻细胞抽提掖对小鼠血液以及免疫系统的亚慢性毒性作用。实验分为3个处理组和1个对照组（每组10只昆明小鼠,雌雄各半）,采用腹腔注射的染毒方法对3个处理组进行暴露,剂量分别为2.4、4.8 和 9.6 μg microcystin-LR/kg body weigh,对照组注射等量的生理盐水,连续注射14d。实验结果表明,14d 染毒后,小鼠的肝体比和脾体比都明显增大（p < 0.05）, 同时在9.6 μg/kg处理组,血清丙氨酸转移酶、天冬氨酸转移酶、乳酸脱氢酶和碱性磷酸酶活性与对照相比明显升高,但血清总蛋白、白蛋白和白蛋白/球蛋白比率下降。这些指标的变化说明,含微囊藻毒素的微囊藻细胞提取液对处理组小鼠肝脏造成了损伤,肝组织学观察也印证了这个结果,在处理组小鼠肝组织有明显的水样变性。另外,9.6 μg/kg处理组小鼠血液白细胞数量比对照组明显减少。组织细胞学观察发现,处理组小鼠脾脏也有明显的损伤。该实验结果说明,含微囊藻毒素的微囊藻细胞抽提液对小鼠的血液和免役系统都产生了一定程度的损伤。     

Melatonin Regulates the Viability and Differentiation of Rat Midbrain Neural Stem Cells

(1) Neurogenesis driven by neural stem cells (NSCs) is regulated by physiological and pathological factors. Melatonin (MT) has profound neurotrophic and neuroprotective effects. Hence, we studied the role of MT in regulating the viability and differentiation of NSCs derived from rat ventral midbrain. (2) NSCs were isolated from the rat ventral midbrain. The viability of NSCs was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-ulfophenyl)-2H-tetrazolium assay. The differentiation of NSCs was examined by analyzing the expression of the neural markers, MT receptors, brain derived neurotropic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) with semi-quantitative RT-PCR, immunofluorescence cytochemistry, and Western blot. (3) Our results showed that MT could promote the viability of NSCs. In addition, MT could significantly elevate the mRNA and protein levels of tyroxine hydroxylase (TH), a marker of dopaminergic neurons, and decrease the expression of the astrocytes maker glial fibrillary acidic protein (GFAP). MT also increased the production of BDNF and GDNF in the cultured NSCs. Meanwhile, we first found that two subtypes of MT receptors, MT1 and MT2, were expressed in the ventral midbrain NSCs. (4) These results demonstrated that MT could induce NSCs to differentiate into dopaminergic neurons and decrease astrocyte production. These findings also suggest that MT could offer a beneficial tool in guiding directional differentiation of NSCs.     

Cell Surface Beta 1, 4-galactosyltransferase 1 promotes apoptosis by inhibiting epidermal growth factor receptor pathway

Our previous studies have shown that overexpression of β1,4-galactosyltransferase1 (β1,4GT1) leads to increased apoptosis induced by cycloheximide (CHX) in SMMC-7721 human hepatocarcinoma cells. However, the role of β1,4GT1 in apoptosis remains unclear. Here we demonstrated that cell surface β1,4GT1 inhibited the autophosphorylation of epidermal growth factor receptor (EGFR) especially at Try 1068. The phosphorylation of protein kinase B (PKB/Akt) and extracellular signal-regulated protein kinase1/2 (ERK1/2), which are downstream molecules of EGFR, were also reduced in cell surface β1,4GT1-overexpressing cells. Furthermore, the translocations of Bad and Bax that are regulated by PKB/Akt and ERK1/2 were also increased in these cells. As a result, the release of cytochrome c from mitochondria to cytosol was increased and caspase-3 was activated. In contrast, RNAi-mediated knockdown of β1,4GT1 increased the autophosphorylation of EGFR. These results demonstrated that cell surface β1,4GT1 may negatively regulate cell survival possibly through inhibiting and modulating EGFR signaling pathway.     

青海锡铁山矿区铅、锌的植物地球化学特征及其与矿的关系

 通过青海锡铁山铅、锌矿区植物群落和植物中铅,锌含量特征的调查研究表明：该区植被为荒漠植被类型。矿带上的植物群落与非矿带上的相比较,群落中种属数目更少,覆盖度更低,植物生长更低矮。植物灰分中的锌含量(平均)为125.9—1144ppm。膜果麻黄(Ephedra przewalskii)含量最高,变化范围最大,为86.11—5871.88ppm。植物中的铅含量为31.32—1129.6ppm。黑柴(Sympegma regelii)含量较高,变化最大,平均为746ppm,极值为14.3—5561.70ppm。在矿带上含量最高,非矿带对照区含量最低。植物及其生长的土壤中金属元素含量之间的关系,无论是铅还是锌含量都有很好的线性关系。膜果麻黄、黑柴、优若藜(Eurotia ceratoides)和中亚紫菀木(Asterothamnus centrali-asiaticus)等植物相关系数均达显著相关水平(α≤0.05)。 这在植物地球化学勘探上是非常有用的。例如中亚紫菀木和琵琶柴(Reaumuria soongorica)中铅的植物地球化学异常,准确地圈出了铅、锌矿的位置,衬度高,异常范围与矿化区基本吻合。     

粘合材料及其在生物医学中的应用：进展与展望

粘合材料作为一种重要的辅助材料,在工业包装、海洋工程以及生物医药等多个领域都有广泛的应用需求。天然存在的粘合剂如贻贝足丝粘合蛋白等具有良好的生物相容性和生物可降解性,但因其来源受限及在生理环境下较弱的粘合性能,因此在生物医药领域的应用受到了限制。从自然生物的粘合现象中汲取灵感,各种利用化学或生物合成方法制备的仿生粘合材料应运而生,针对生物医药领域的特定需求,一些新兴粘合材料在生物相容性、生物可降解性以及组织粘附等方面都表现出在医药领域应用的潜力。展望未来,受自然粘合材料兼具环境响应、自我再生和自修复等特征的启迪,各种生物灵感和生物仿生粘合材料的开发势必是未来的发展热点,而合成生物学技术为创建具有上述特征的活体粘合材料提供了新的可能。     

土壤微生物对气候变暖和大气N沉降的响应

气候变暖和大气N沉降是近一、二十年来人们非常关注的全球变化现象,它们所带来的一系列生态问题已成为全球变化研究的重要议题。它们不仅影响地上植被生长和群落组成,还直接或间接地影响土壤微生物过程,而土壤微生物对此做出的响应正是生态系统反馈过程中非常重要的环节。该文分别从气候变化对土壤微生物的影响(土壤微生物量、微生物活动和微生物群落结构)和土壤微生物对气候变化的响应(凋落物分解、养分利用与循环以及养分的固持与流失)两个角度,综述近期土壤微生物对气候变暖和大气N沉降响应与适应的研究进展。气候变暖和大气N沉降对土壤微生物的影响更多地反映在微生物群落的结构和功能上,而土壤微生物量、微生物活动和群落结构的变化又会通过改变凋落物分解、养分利用和C、N循环等重要的土壤生态系统功能和过程做出响应,形成正向或负向反馈,加强或削弱气候变化给整个陆地生态系统带来的影响。然而,到目前为止土壤微生物的响应对陆地生态系统产生的最终结果仍是未决的关键性问题。     

香港嘉道理农场次生林区碰撞诱捕网和黑光灯捕虫器采集所得鞘翅目甲虫多样性比较

本文根据1990-1995年在香港嘉道理农场次生林区采集的昆虫标本,首次分析了鞘翅目及其优势科的种类、数量和季节性变化,以及由碰撞诱捕网和黑光灯捕虫器采集所得甲虫在种类、数量和季节性上的差异。在13260号标本中,已鉴定到科的有13253号,分属45科,231种。其中,朽木甲科(Alleculidae)、毛蕈甲科(Biphyllidae)、丸甲科(Byrrhidae)、坚甲科(Colydiidae)、拟球甲科(Corylophidae)、隐食甲科(Cryptophagidae)、水缨甲科(Hydroscaphidae)、伪叶甲科(Lagliidae)、薪甲科(Lathridiidae)、泽甲科(Limnichidae)、黑蕈甲科(Zopheridae)等11个科为香港地区的首次报道,约占本次调查科总数的25％。分析表明：(1)该次生林区的鞘翅目甲虫以蛀木性为主。天牛科(Cerambycidae)、瓢虫科(Coccinellidae)、象甲科(Curculionidae)、花蚤科(Mordellidae)、金龟甲科(Scarabaeidae)、小蠹科(Scolytidae)等6科均为多样性较高(种类≥15或者个体数量≥200)的优势科。(2)鞘翅目个体数量季节性明显,每年自2月开始数量逐渐增加,6—7月为甲虫发生的高峰期,8月显著减少。各优势科甲虫的季节性也存在一定的差异,庞大的小蠹标本数量(85％)说明在此调查期间该科正处于大发生时期。(3)黑光灯捕虫器所捕的甲虫科类和种类较之碰撞诱捕网所捕不尽相同,黑光灯捕虫器所捕的甲虫数量发生高峰期比碰撞诱捕网所捕的甲虫提前一个月。(4)各项多样性指数对不同捕虫器采集所得鞘翅目的测度差异明显,黑光灯捕虫器所捕甲虫的多样度和均匀度指数高于碰撞诱捕网。     

枯草芽孢杆菌微生态制剂发酵研究进展

微生态制剂是饲用抗生素的绿色有效替代品。枯草芽孢杆菌在逆境中可形成抗逆性强的芽孢,在生产和应用过程中保持高活性,是一种高效的微生态制剂菌种。提高枯草芽孢杆菌活菌数及芽孢率是保证微生态制剂产品质量的关键。本文综述了枯草芽孢杆菌芽孢形成的分子生物学机制及影响芽孢形成的重要因素,进一步比较枯草芽孢杆菌微生态制剂不同发酵方式的特点,重点阐述了提高枯草芽孢杆菌有效生物量的工艺优化,最后介绍了枯草芽孢杆菌微生态制剂的应用,并对将来研究思路进行了讨论。     

Heterogeneous impact of cytomegalovirus reactivation on nonrelapse mortality in hematopoietic stem cell transplantation

This study aims to retrospectively analyze the efficacy of penciclovir in the prevention of viral infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Ninety-six patients with allo-HSCT were enrolled, who were treated at the Medical Center of Hematology of Xinqiao Hospital from June 2020 to September 2021. The experimental and control groups were treated with penciclovir and acyclovir, respectively, to prevent viral infection. By February 2022, the infection rates of cytomegalovirus, BK virus, JC virus, and Epstein-Barr virus (EBV) in the experimental group and the control group were 18.8% and 39.06% (P<0.05), 28.1% and 25% (P>0.05), 6.2% and 7.81% (P>0.05), 21.8% and 23.43% (P>0.05), respectively. The infection-related urinary system symptoms of the experimental group and the control group occurred in 4 and 9 patients, respectively, of which 3 and 9 patients died, respectively. Penciclovir can significantly reduce the cytomegalovirus infection rate after allo-HSCT and has better preventive effects than acyclovir without obvious side effects. The effectiveness and safety of penciclovir will be further verified in the future.