一株中温淀粉酶菌株的分离鉴定及其产酶条件分析

利用固体淀粉筛选培养基,从安阳市郊区面粉厂附近的土壤里分离筛选出1株产淀粉酶的菌株,编号为MF-3-2.经过菌株形态、革兰氏染色、16S rDNA鉴定及系统进化树分析,初步确定其为枯草芽孢杆菌(Bacillus subtilis).摇瓶培养后对其酶学性质研究发现,该菌株淀粉酶的最适温度为65℃,最适pH值为6.0,在pH值4.8～6.0范围内仍能残余70％以上的酶活力.该菌株的最适生长温度为40℃,最适生长pH值为6.5.产酶条件优化结果表明:最适碳源为马铃薯淀粉,最适氮源为豆粕粉,最适碳氮比为1∶15,发酵温度30℃,发酵pH值6.0,装液量10％,种龄10h,接种量5％,转速200 r/min,48 h达到产酶高峰.通过发酵产酶条件优化,其淀粉酶活性达到86.8 U/mL,是优化前的35倍.另外,在酸性条件下还具有较好的活性.因此,该菌株的淀粉酶具有潜在的工业应用前景.     

短期生长环境光强骤增导致典型阴生植物三七光系统受损的机制

阴生植物突然暴露在强光下造成光损伤的情况时有发生, 但其对高光敏感的潜在机制尚不十分清楚。为阐明阴生植物无法在自然全光照环境下生存的相关机制, 该研究以典型阴生植物三七(Panax notoginseng)为材料, 将遮阴环境下(10%透光率)生长的植株转移到全日光环境下3天, 研究其相对叶绿素含量(SPAD值)、光合参数以及叶绿素荧光参数的变化。结果表明, 全光环境下三七光合日变化呈现“双峰”曲线特征, 且净光合速率在处理期间逐日降低。全日光下三七叶片SPAD值、水分利用率和光能利用率显著降低; 叶片光系统I (PSI)反应中心P700最大荧光信号、光系统II (PSII)电子传递速率、暗适应下PSII最大量子效率和光下PSII最大量子效率显著低于遮阴环境下的植株, 且至傍晚不能完全恢复。而参与调节性能量耗散的量子产量、PSI受体侧限制引起的非光化学量子产量、环式电子流则显著高于遮阴环境下的三七。此外, 生长环境光照强度骤增导致荧光诱导动力学曲线发生明显变化, 并显著升高了PSII供体侧和受体侧的荧光产量。当阴生植物三七突然暴露于全光环境下时, 强烈的光照会导致PSII供体侧的放氧复合体活性受损, 抑制受体侧的电子传递, 过度还原PSI的受体侧进而引发PSI光抑制。该研究结果揭示, 全日光导致的PSII不可逆损伤和PSI光抑制可能是典型阴生植物三七为什么不能在全日照光环境下存活的重要原因。     

抗生素诱导的呼吸道菌群缺失对小鼠RSV感染的影响

目的探究抗生素雾化暴露引起的呼吸道菌群缺失对小鼠呼吸道合胞病毒(RSV)感染的影响,为临床合理使用抗生素提供指导意见。方法32只BALB/c小鼠分为2组:雾化ddH₂O对照组和雾化ABX组合抗生素组,处理6 d后,进行细菌16S rRNA基因PCR检测,构建呼吸道菌群缺失小鼠模型。上述2组组内再随机分为2小组,即PBS对照组(ddH₂O+PBS,ABX+PBS)和RSV感染组(ddH₂O+RSV,ABX+RSV),饲养至第14天。检测和分析各组小鼠支气管肺泡灌洗液(BALF)中的炎症细胞和相关细胞因子(TNF-α、IL-8、IL-10及MCP-1)的数量和水平,观察肺组织病理学状况及检测病毒载量。结果BALF中细菌DNA提取和16S rRNA基因PCR检测显示,雾化ABX组合抗生素处理能够有效地剔除呼吸道菌群。BALF中炎症细胞和相关细胞因子检测显示,ABX+RSV组炎症细胞总数明显增多(P<0.05),分类以巨噬细胞和淋巴细胞为主;且细胞因子TNF-α、IL-8、MCP-1及IL-10水平显著升高(均P<0.05)。肺部HE染色显示,感染RSV后ddH₂O+RSV组和ABX+RSV组小鼠肺部损伤明显加重(均P≤0.01),与ddH₂O+RSV组相比较,ABX+RSV组的病毒载量明显升高(t=2.7160,P=0.0217)。结论雾化ABX组合抗生素不仅能够有效地剔除呼吸道菌群,而且明显增加了小鼠感染RSV的风险,导致呼吸道炎症加重,以及病毒载量升高。     

北京市主城区不透水面时空演变及其热环境效应研究

城市不透水面是表征城市化进程的重要指标,开展城市不透水面研究对生态环境监测及城市建设规划具有重要意义。以北京市主城区为研究区,基于Landsat影像采用支持向量机(SVM)和线性光谱混合分解模型(LSMM)相结合的方法提取研究区2002年、2009年和2017年三期不透水面;同时采用辐射传输方程法反演研究区地表温度,分析北京市主城区不透水面时空格局演变及其与城市热环境的相关性。研究结果表明:2002—2017年,北京市主城区近15年不透水面聚集度较高且呈持续增长趋势,东、西城区不透水面面积占比最高,朝阳区和海淀区不透水面增长速率和增长强度相对较大。北京市主城区不透水面呈放射状扩张趋势且增长集中在四环以外的区域,不透水面盖度高值区面积不断增加。研究区近15年地表温度持续升高,热岛效应加剧,地表温度高值区与城市建筑区空间分布存在一致性。不透水面空间格局与热环境高度相关,不透水面的斑块密度和破碎度与地表温度呈负相关,斑块所占景观比例及最大斑块指数与地表温度呈正相关,可通过合理控制相关景观指标、优化不透水面空间格局控制地表温度。在此基础上提出了缓解城市热岛效应的建议:增加树木、草地等用地类型;将不透水面分割成许多小斑块,减少大面积不透水面区域分布;使用透水性材料等。     

阿特拉津降解菌ATR3的分离鉴定与土壤修复

阿特拉津因效率高、价格低廉,是我国玉米田施用最广泛的除草剂之一,但其结构稳定,残留时间长,因此对生态环境和人类健康造成了一定的危害。从长期受阿特拉津污染的玉米田土壤中筛选并鉴定阿特拉津降解菌,明确其在不同类型土壤中的去除能力。对分离出的阿特拉津降解菌ATR3进行生理生化分析和16S rRNA序列鉴定,确定菌株ATR3为节杆菌属（Arthrobacter sp.）。该菌株以阿特拉津为唯一氮源,培养48 h后对1 000 mg/L阿特拉津的去除率达到97%以上。敏感作物盆栽试验结果表明,阿特拉津在棕壤上去除最快,褐土次之,黑土最慢,说明阿特拉津在土壤中的去除过程与土壤本身的理化性质呈相关关系。同时,该菌株处理14 d后,能明显恢复玉米的各项生物学指标,说明该菌株对阿特拉津污染土壤具有良好的修复能力。为阿特拉津降解菌剂的推广利用提供参考。     

贵州省藜芦科一新记录属——白丝草属

报道贵州省藜芦科一新记录属——白丝草属Chamaelirium Willd.,一新记录种——中国白丝草Chamaelirium chinense (K. Krause) N. Tanaka,并对该种的形态特征、生境、分类变动进行描述及讨论。     

Characterization of complement 1q binding protein of tiger shrimp,Penaeus monodon,and its C1q binding activity

The receptor for the globular heads of C1q, C1qBP/gC1qR/p33, is a multicompartmental, multifunctional cellular protein with an important role in infection and in inflammation. In the present study, we identified and characterized the complement component 1q subcomponent binding protein (C1qBP) from the tiger shrimp Penaeus monodon (designated as PmC1qBP). The open reading frame of PmC1qBP encodes 262 amino acid residues with a conserved MAM33 domain, an arginine-glycine-aspartate cell adhesion motif, and a mitochondrial targeting sequence in the first 53 amino acids. PmC1qBP shares 32%–81% similarity with known C1qBPs and clusters with lobster gC1qR under phylogenetic analysis. The temporal PmC1qBP mRNA expression in the hepatopancreas was significantly enhanced at 9 h after Vibrio vulnificus challenge. The native PmC1qBP was expressed in the gills, hepatopancreas, ovaries, and intestines as a precursor (38 kDa) and the active peptide (35 kDa). The recombinant PmC1qBP protein was expressed in Escherichia coli BL21, and was purified using nickel–nitrilotriacetic acid agarose. A complement 1q binding assay indicated that the rC1qBP protein competitively binds to C1q in mouse serum. The data reveal that PmC1qBP is not only involved in shrimp immune responses to pathogenic infections, but also cross-binding to the mouse C1q.     

RGMb/DRAGON与BMP信号转导

RGMb/DRAGON为RGM家族成员之一,在许多组织和器官中存在并表达.最初它作为粘附分子在神经系统中调节轴突排斥被发现.近来研究发现,它还是BMP的辅助受体,与BMP配体和受体结合,通过调控BMP信号通路在繁殖、肾脏机能的维持以及免疫疾病等生理和病理条件下发挥重要作用.本文评述了RGMb的基因及蛋白结构特征、表达定位及其在神经系统中的作用,并重点介绍了其在BMP信号通路中的作用机制和生物学研究进展.     

A Novel PRPF31 Mutation in a Large Chinese Family with Autosomal Dominant Retinitis Pigmentosa and Macular Degeneration

Purpose

This study was intended to identify the disease causing genes in a large Chinese family with autosomal dominant retinitis pigmentosa and macular degeneration.

Methods

A genome scan analysis was conducted in this family for disease gene preliminary mapping. Snapshot analysis of selected SNPs for two-point LOD score analysis for candidate gene filter. Candidate gene PRPF31 whole exons'' sequencing was executed to identify mutations.

Results

A novel nonsense mutation caused by an insertion was found in PRPF31 gene. All the 19 RP patients in 1085 family are carrying this heterozygous nonsense mutation. The nonsense mutation is in PRPF31 gene exon9 at chr19:54629961-54629961, inserting nucleotide “A” that generates the coding protein frame shift from p.307 and early termination at p.322 in the snoRNA binding domain (NOP domain).

Conclusion

This report is the first to associate PRPF31 gene''s nonsense mutation and adRP and JMD. Our findings revealed that PRPF31 can lead to different clinical phenotypes in the same family, resulting either in adRP or syndrome of adRP and JMD. We believe our identification of the novel “A” insertion mutation in exon9 at chr19:54629961-54629961 in PRPF31 can provide further genetic evidence for clinical test for adRP and JMD.     

Impact of Functional Constipation on Health-Related Quality of Life in Preschool Children and Their Families in Xi’an,China

Aim

Functional constipation (FC) is one of the common diseases among children. The aim of this study was to investigate the health-related quality of life (HRQOL) in preschool children diagnosed with FC and the impact of the condition on affected families.

Methods

In this cross-sectional, case-control study, 152 children aged 3–6 years with FC, 176 healthy children aged 3–6 years without FC, and their primary caregivers were selected. Chinese versions of the PedsQL^TM 4.0 Generic Core Scale and the Family Impact Module (FIM) were used to assess childhood HRQOL and the impact of FC on family members, respectively. HRQOL scores were compared between children with FC and healthy children. In addition, a multiple step-wise regression with demographic variables of children and their caregivers, family economic status, duration and symptoms of FC, as independent variables, was used to determine factors that influenced HRQOL in children and had impacted caregivers.

Results

Scores of physical, emotional, social and school functions, and summary scales were significantly lower in children with FC than in healthy children (p < 0.05). Physical, emotional, social, cognitive, and communication scores for caregivers, as well as daily activities and relationships for families of children with FC, were significantly lower than those of caregivers and families with healthy children (p < 0.05). Children’s ages, duration of FC, symptoms of FC, the child-caregiver relationship, family economic status, and caregiver education level emerged as the main factors influencing HRQOL in children, caregivers, and family members.

Conclusions

FC had a significant impact on HRQOL of affected children and their caregivers, as well as their family functions. Social characteristics of children and caregivers, duration and symptoms of FC and family economic status significantly affected HRQOL of children and caregivers, as well as family functions of children with FC.