Active Bacterial Populations and Grazing Impact Revealed by an In Situ Experiment in a Shallow Aquifer

To elucidate bacterial population dynamics in an aquifer, we attempted to reveal the impact of protozoan grazing on bacterial productivity and community structure by an in situ incubation experiment using a diffusion chamber. The abundance and vertical distribution of bacteria and protozoa in the aquifer were revealed using wells that were drilled in a sedimentary rock system in Itako, Ibaraki, Japan. The water column in the wells possessed aerobic and anaerobic layers. Active bacterial populations under the grazing pressure of protozoa were revealed through in situ incubation with grazer eliminating experiment by the filtration. On August 19, 2003, the total number of bacteria (TDC) decreased from 1.5 × 10⁶ cells ml^{? 1} at 2.2 m depth to 3.0 × 10⁵ cells ml^{? 1} at 10 m depth. The relative contribution of the domain Bacteria to TDC ranged between 63% and 84%. Protozoa existed at a density of 4.2 × 10⁴ to 1.9 × 10⁵ cells ml^{? 1} in both aerobic and microaerobic conditions. A grazing elimination experiment in situ for 6 days brought about clearly different bacterial community profiles between the 2.2 m and 10 m samples. The bacterial composition of the initial community was predominantly β- and γ -proteobacteria at 2.2 m, while at 10 m β-, α - and γ -proteobacteria represented 56%, 26% and 13% of the community, respectively. The distribution of bacterial abundance, community composition and growth rates in the subsurface were influenced by grazing as well as by geochemical factors (dissolved oxygen and concentrations of organic carbon, methane and sulfate). Results of the in situ incubation experiment suggested that protozoan grazing contributes significantly to bacterial population dynamics.     

微区XRF技术分析无机元素在植物中的原位分布

植物的无机元素分布特征对植物生理过程具有重要的指标作用, 可揭示营养物质分布、代谢途径及毒理耐受性等多种生命过程。用微区XRF技术测试样品中无机元素的分布, 具有原位无损、可进行较大面积样品连续成像分析以及前处理过程简单等诸多优势。将微区XRF技术应用于植物样品不同器官的无机元素分布检测, 旨在探讨该技术在植物样品测试中的仪器参数选择、样品前处理方法和数据后处理手段等对测试结果的影响。为得到可靠的实验结果, 对不同含水量的器官进行不同的前处理, 并比较不同驻留时间、测试腔体真空与否等仪器条件对测试结果的影响, 同时对数据处理方法进行探索, 包括对获得的数据进行图像叠加及对不同元素浓度比例进行半定量分析。研究结果表明, 微区XRF技术测试植物样品中无机元素分布具有一定的技术优势。     

Analysis of In Situ Distribution of Inorganic Elements in Plants by Micro-XRF

植物的无机元素分布特征对植物生理过程具有重要的指标作用, 可揭示营养物质分布、代谢途径及毒理耐受性等多种生命过程。用微区XRF技术测试样品中无机元素的分布, 具有原位无损、可进行较大面积样品连续成像分析以及前处理过程简单等诸多优势。将微区XRF技术应用于植物样品不同器官的无机元素分布检测, 旨在探讨该技术在植物样品测试中的仪器参数选择、样品前处理方法和数据后处理手段等对测试结果的影响。为得到可靠的实验结果, 对不同含水量的器官进行不同的前处理, 并比较不同驻留时间、测试腔体真空与否等仪器条件对测试结果的影响, 同时对数据处理方法进行探索, 包括对获得的数据进行图像叠加及对不同元素浓度比例进行半定量分析。研究结果表明, 微区XRF技术测试植物样品中无机元素分布具有一定的技术优势。     

化学发光杂交进行菌落克隆的原位筛选

用化学发光杂交试剂代替３２Ｐ进行菌落原位筛选重组Ｐ５３阳性克隆,可减少同位素的放射性损害和污染及半衰期短等缺点．本方法实验周期短、特异性可和同位素相当,可用于重组目的基因的原位杂交筛选．     

Beneficial Effect of Acetic Acid on the Xylose Utilization and Bacterial Cellulose Production by Gluconacetobacter xylinus

In this work, acetic acid was found as one promising substrate to improve xylose utilization by Gluconacetobacter xylinus CH001. Also, with the help of adding acetic acid into medium, the bacterial cellulose (BC) production by G. xylinus was increased significantly. In the medium containing 3 g l⁻¹ acetic acid, the optimal xylose concentration for BC production was 20 g l⁻¹. In the medium containing 20 g l⁻¹ xylose, the xylose utilization and BC production by G. xylinus were stimulated by acetic acid within certain concentration. The highest BC yield (1.35 ± 0.06 g l⁻¹) was obtained in the medium containing 20 g l⁻¹ xylose and 3 g l⁻¹ acetic acid after 14 days. This value was 6.17-fold higher than the yield (0.21 ± 0.01 g l⁻¹) in the medium only containing 20 g l⁻¹ xylose. The results analyzed by FE-SEM, FTIR, and XRD showed that acetic acid affected little on the microscopic morphology and physicochemical characteristics of BC. Base on the phenomenon observed, lignocellulosic acid hydrolysates (xylose and acetic acid are main carbon sources present in it) could be considered as one potential substrate for BC production.     

Temporal Expression of Mouse Glial Fibrillary Acidic Protein mRNA Studied by a Rapid In Situ Hybridization Procedure

A rapid and sensitive in situ hybridization technique is described for the detection of mRNA sequences in 6-8-micron cryostat sections. The method incorporates the use of alpha-thio-35S-labelled nucleoside triphosphates for the generation of high-specific-activity DNA probes and a high-stringency washing procedure that virtually eliminates background without unduly compromising histological integrity. Whereas signal resolution is less than that observed using 3H probes, 35S-labelled probes are well-suited for experiments where resolution at the cellular level is required. The method has been applied to a study of the developmental regulation of glial fibrillary acidic protein (GFAP) mRNA expression in developing mouse brain. GFAP-specific sequences are first detectable after the second postnatal day, and thereafter rise to a level that is maintained throughout development and into adulthood. The distribution of GFAP-encoding sequences broadly reflects the known distribution of astrocytes, but the levels of mRNA within these cells vary by a surprisingly large amount depending on their location. For example, in adult animals, the astrocytes of the glial limitans contain an abundance of GFAP-specific mRNA that is higher than corresponding levels in astrocytes in the cerebellar white matter, whereas these cells in turn contain considerably more GFAP-specific mRNA than astrocytes in the gray matter of the cerebrum. Unexpectedly, parallel RNA blot transfer experiments show the existence of some GFAP-encoding mRNA size heterogeneity that is restricted to the first postnatal week.     

In Situ Hybridization Evidence of Differential Modulation by Pentobarbital of GABAA Receptor α1- and β3-Subunit mRNAs

Abstract: Tolerance to and withdrawal from pentobarbital were induced in rats by continuous intracerebroventricular infusion via subcutaneously implanted osmotic minipumps. In situ hybridization of GABA_A receptor α₁- and β₃-subunit mRNA was conducted using synthetic 3'- end ³⁵S-dATP-labeled oligodeoxynucleotide probes. Results were quantified by film densitometry. In animals that were tolerant to pentobarbital, levels of α₁-subunit mRNA were decreased in hippocampus, superior colliculus, and inferior colliculus, but levels of β₃-subunit mRNA were not affected. Dramatically increased levels of GABA_A receptor subunit mRNA were observed in animals 24 h after withdrawal from chronic pentobarbital treatment. These increases occurred in cerebral cortex and cerebellum for the α₁ subunit and in cerebral cortex only for the β₃-subunit. These data provide further support to the structural and pharmacological GABA_A receptor heterogeneity in discrete brain areas. The observed changes of subunit expression may underlie, at least in part, the receptor up- and down-regulation observed in receptor ligand binding studies.     

Monitoring impact of in situ biostimulation treatment on groundwater bacterial community by DGGE

Changes in bacterial diversity during the field experiment on biostimulation were monitored by denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rDNA fragments. The results revealed that the bacterial community was disturbed after the start of treatment, continued to change for 45 days or 60 days and then formed a relatively stable community different from the original community structure. DGGE analysis of soluble methane monooxygenase (sMMO) hydroxylase gene fragments, mmoX, was performed to monitor the shifts in the numerically dominant sMMO-containing methanotrophs during the field experiment. Sequence analysis on the mmoX gene fragments from the DGGE bands implied that the biostimulation treatment caused a shift of potential dominant sMMO-containing methanotrophs from type I methanotrophs to type II methanotrophs.     

Bacterial diversity and community composition in the chemocline of the meromictic alpine Lake Cadagno as revealed by 16S rDNA analysis

Using different techniques of molecular biology we investigated the bacterial diversity of the chemocline of the meromictic Lake Cadagno. Cloning of a total community 16S rDNA PCR product and subsequent screening with a combination of amplified ribosomal DNA restriction analysis and temporal temperature gradient gel electrophoresis (TTGE) analysis revealed that 30 of 47 randomly selected clones were unique. Partial sequencing and comparative analysis indicated a high bacterial diversity dominated by the gamma-Proteobacteria (33.3%). Most of these rDNA clone sequences were not closely related to any 16S rDNA sequence in the database. In a second approach, the TTGE pattern from an environmental sample was compared with the migration of the cloned 16S rDNA fragments. Four clone types were identified on the environmental pattern by excising and sequencing comigrating bands, three of which were well represented in the library: two Chromatiaceae species and one sequence affiliated with the Desulfobulbus assemblage. Using the fluorescent in situ hybridization technique we essentially confirmed the results of the cloning experiments and the TTGE analysis.     

Enhanced Cyclability of Lithium–Oxygen Batteries with Electrodes Protected by Surface Films Induced via In Situ Electrochemical Process

Although the rechargeable lithium–oxygen (Li–O₂) batteries have extremely high theoretical specific energy, the practical application of these batteries is still limited by the instability of their carbon‐based air‐electrode, Li metal anode, and electrodes, toward reduced oxygen species. Here a simple one‐step in situ electrochemical precharging strategy is demonstrated to generate thin protective films on both carbon nanotubes (CNTs), air‐electrodes and Li metal anodes simultaneously under an inert atmosphere. Li–O₂ cells after such pretreatment demonstrate significantly extended cycle life of 110 and 180 cycles under the capacity‐limited protocol of 1000 mA h g^?1 and 500 mA h g^?1, respectively, which is far more than those without pretreatment. The thin‐films formed from decomposition of electrolyte during in situ electrochemical precharging processes in an inert environment, can protect both CNTs air‐electrode and Li metal anode prior to conventional Li–O₂ discharge/charge cycling, where reactive reduced oxygen species are formed. This work provides a new approach for protection of carbon‐based air‐electrodes and Li metal anodes in practical Li–O₂ batteries, and may also be applied to other battery systems.     

尺神经原位松解术与尺神经皮下前置术治疗肘管综合征近期疗效比较的回顾性研究

目的:比较尺神经原位松解术与尺神经皮下前置术治疗肘管综合征(CuTS)近期疗效。方法:本研究为回顾性研究,选取2016年7月～2017年7月期间我院二部收治的60例CuTS患者,根据手术方式的不同分为A组(n=32,尺神经原位松解术)和B组(n=28,尺神经皮下前置术),比较两组患者优良率、并发症、围术期指标、感觉运动功能(肌力、小指指端两点辨别觉、神经传导速度)以及DASH上肢功能障碍(DASH)评分。结果:B组术后12个月的优良率为92.86%(26/28),高于A组的68.75%(22/32)(P0.05)。两组术后并发症总发生率比较差异无统计学意义(P0.05)。两组术后12个月肌力、神经传导速度升高,且B组高于A组(P0.05),两组术后12个月小指指端两点辨别觉降低,且B组低于A组(P0.05)。两组术后3个月、术后6个月、术后12个月DASH评分呈下降趋势,且B组低于A组(P0.05)。B组手术切口长度、手术时间长于A组(P0.05),两组术后住院时间比较差异无统计学意义(P0.05)。结论:与尺神经原位松解术相比,尺神经皮下前置术治疗CuTS患者,虽然手术切口长度、手术时间相对较长,但其优良率更高,同时可有效恢复患者感觉运动功能及减轻其上肢功能障碍,且不增加并发症发生率,具有一定的临床应用价值。     

Expression of Cytochrome P450 Side-Chain Cleavage Enzyme and 3β-Hydroxysteroid Dehydrogenase in the Rat Central Nervous System: A Study by Polymerase Chain Reaction and In Situ Hybridization

Abstract: In examining steroid synthesis in the CNS, expression of the mRNAs encoding for cytochrome P450 side-chain cleavage enzyme (P450_SCC) and 3β-hydroxysteroid dehydrogenase/Δ⁵-Δ⁴ isomerase (3β-HSD) has been studied in the rat brain. P450_SCC transforms cholesterol into pregnenolone and 3β-HSD transforms pregnenolone into progesterone. PCR was used to amplify cDNA sequences from total RNA extracts. Classical steroidogenic tissues, like adrenal and testis, as well as the non-steroidogenic tissue lung have been used as controls. The expression of P450_SCC and 3β-HSD have been demonstrated by PCR in cortex, cerebellum, and spinal cord. In addition, primary cultures of rat cerebellar glial cells and rat cerebellar granule cells were found to express P450_SCC and 3β-HSD at comparable levels. Furthermore, three of the four known isoenzymes of 3β-HSD were identified, as determined using selective PCR primers coupled with discriminative restriction enzymes and sequencing analysis of the amplified brain products. Using RNA probes, in situ hybridization indicated that P450_SCC and 3β-HSD are expressed throughout the brain at a low level and mainly in white matter. Enrichment of glial cell cultures in oligodendrocytes, however, does not increase the relative abundance of P450_SCC and 3β-HSD mRNA detected by PCR. This discrepancy suggests that the developmental state of cultured cells and their intercellular environment may be critical for regulating the expression of these enzymes. These findings support the proposal that the brain apparently has the capacity to synthesize progesterone from cholesterol, through pregnenolone, but that the expression of these enzymes appears to be quite low. Furthermore, the identification of these messages in cerebellar granule cell cultures implies that certain neurons, in addition to glial cells, may express these steroidogenic enzymes.     

Karyotyping of Brassica napus L. Based on C0t-1 DNA Banding by Fluorescence In Situ Hybridization

In order to precisely recognize and karyotype Brassica napus L. chromosomes, C0t-1 DNA was extracted from its genomic DNA, labeled with biotin-1 1-dUTP and in situ hybridized. The hybridized locations were detected by Cy3-conjugated streptavidin. Specific fluorescence in situ hybridization （FISH） signal bands were detected on all individual chromosome pairs. Each chromosome pair showed specific banding patterns. The B. napus karyotype has been constructed, for the first time, on the basis of both Cot-1 DNA FISH banding patterns and chromosome morphology.     

Deciphering the Reaction Mechanism of Lithium–Sulfur Batteries by In Situ/Operando Synchrotron‐Based Characterization Techniques

Lithium–sulfur (Li–S) batteries have received extensive attention as one of the most promising next‐generation energy storage systems, mainly because of their high theoretical energy density and low cost. However, the practical application of Li–S batteries has been hindered by technical obstacles arising from the polysulfide shuttle effect and poor electronic conductivity of sulfur and discharge products. Therefore, it is of profound significance for understanding the underlying reaction mechanism of Li–S batteries to circumvent these problems and improve the overall battery performance. Advanced characterization techniques, especially synchrotron‐based X‐ray techniques, have been widely applied to the mechanistic understanding of Li–S batteries. Specifically, in situ/operando synchrotron‐based techniques allows chemical and structural evolution to be directly observed under real operation conditions. Here, recent progress in the understanding of the operating principles of Li–S batteries based on in situ/operando synchrotron‐based techniques, including X‐ray absorption spectroscopy, X‐ray diffraction, and X‐ray microscopy, is reviewed. The aim of this progress report is to provide a comprehensive treatise on in situ/operando synchrotron‐based techniques for mechanism understanding of Li–S batteries, and thereby provide guidance for optimizing their overall electrochemical performances.     

Inactivation of Rhodospirillum rubrum coupling factor by 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole. Modification of a tyrosine protected by phosphate

Chemical modification of Rhodospirillum rubrum chromatophores by 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) results in inactivation of photophosphorylation, Mg²⁺-ATPase, oxidative phosphorylation and ATP-driven transhydrogenase, with apparent first-order kinetics. Other energy-linked reactions such as light-driven transhydrogenase and light-dependent proton uptake were insensitive to NBD-Cl. The Ca²⁺-ATPase activity of the soluble coupling factor from chromatophores (R. rubrum F₁) was inactivated by NBD-Cl with kinetics resembling those described for Mg²⁺-ATPase and photophosphorylation activities of chromatophores. Both NBD-chromatophores and NBD-R. rubrum F₁ fully recovered their activities when subjected to thiolysis by dithioerythritol. Phosphoryl transfer reactions of chromatophores and Ca²⁺-ATPase activity of R. rubrum F₁ were fully protected by 5 mM P_i against modification by NBD-Cl. ADP or ATP afforded partial protection. Analysis of the protection of Ca²⁺-ATPase activity by P_i indicated that NBD-Cl and P_i are mutually exclusive ligands. Spectroscopic studies revealed that tyrosine and sulfhydryl residues in R. rubrum F₁ underwent modification by NBD-Cl. However, the inactivation was only related to the modification of tyrosine groups.     

正常与重金属铅注射的兔脑蛋白质双向电泳图谱比较与鉴定

重金属污染对人类健康的威胁日益受到关注,为了了解大量重金属摄入对脑蛋白质的影响,对比研究了正常兔脑组织蛋白质与重金属铅腹腔注射2周后的兔脑组织在蛋白质双向电泳图谱中的差异,分析重金属注射对脑蛋白质表达的可能影响.通过对脑组织蛋白质的提取,分离出水溶性的蛋白质组分,经双向电泳图谱比较正常与注射重金属铅的兔子在脑蛋白质表达上的差异,其中3个蛋白质斑点经提取,反相高效液相色谱(RP-HPLC)分离,基质辅助激光解析电离质谱(MALDI-TOF MS)确定了分子质量,并利用肽质量指纹图谱检索数据库确定蛋白质的归属.实验结果表明正常兔脑与金属铅注射的兔脑在水溶性蛋白质的表达上具有显著性差异.