BACKGROUND & AIMS: :Of the sugars recovered from lignocellulose, D-glucose can be readily converted into ethanol by baker's or brewer's yeast (Saccharomyces cerevisiae). However, xylose that is obtained by the hydrolysis of the hemicellulosic portion is not fermentable by the same species of yeasts. Xylose fermentation by native yeasts can be achieved via isomerization of xylose to its ketose isomer, xylulose. Isomerization with exogenous xylose isomerase (XI) occurs optimally at a pH of 7-8, whereas subsequent fermentation of xylulose to ethanol occurs at a pH of 4-5. We present a novel scheme for efficient isomerization of xylose to xylulose at conditions suitable for the fermentation by using an immobilized enzyme system capable of sustaining two different pH microenvironments in a single vessel. The proof-of-concept of the two-enzyme pellet is presented, showing conversion of xylose to xylulose even when the immobilized enzyme pellets are suspended in a bulk solution whose pH is sub-optimal for XI activity. The co-immobilized enzyme pellets may prove extremely valuable in effectively conducting "simultaneous isomerization and fermentation" (SIF) of xylose. To help further shift the equilibrium in favor of xylulose formation, sodium tetraborate (borax) was added to the isomerization solution. Binding of tetrahydroxyborate ions to xylulose effectively reduces the concentration of xylulose and leads to increased xylose isomerization. The formation of tetrahydroxyborate ions and the enhancement in xylulose production resulting from the complexation was studied at two different bulk pH values. The addition of 0.05 M borax to the isomerization solution containing our co-immobilized enzyme pellets resulted in xylose to xylulose conversion as high as 86% under pH conditions that are suboptimal for XI activity. These initial findings, which can be optimized for industrial conditions, have significant potential for increasing the yield of ethanol from xylose in an SIF approach.

背景与目标： : 在从木质纤维素中回收的糖中，D-葡萄糖可以很容易地通过面包师或啤酒酵母 (酿酒酵母) 转化为乙醇。但是，通过半纤维素部分的水解获得的木糖不能被相同种类的酵母发酵。天然酵母的木糖发酵可以通过将木糖异构化为其酮糖异构体木酮糖来实现。外源木糖异构酶 (XI) 的异构化最佳地发生在7-8的pH下，而随后的木糖发酵为乙醇发生在4-5的pH下。我们提出了一种新颖的方案，该方案通过使用能够在单个容器中维持两个不同pH微环境的固定化酶系统，在适合发酵的条件下将木糖高效异构化为木酮糖。提出了两酶颗粒的概念验证，即使将固定化的酶颗粒悬浮在pH对于XI活性次优的本体溶液中，也显示了木糖向木酮糖的转化。共固化酶颗粒在有效进行木糖的 “同时异构化和发酵” (SIF) 方面可能非常有价值。为了帮助进一步改变平衡以促进木酮糖的形成，将四硼酸钠 (硼砂) 添加到异构化溶液中。四羟基硼酸根离子与木酮糖的结合有效地降低了木酮糖的浓度，并导致木糖异构化增加。在两个不同的本体ph值下研究了四羟基硼酸根离子的形成和络合引起的木酮糖生产的增强。向含有我们的共固定化酶颗粒的异构化溶液中添加0.05 M硼砂导致木糖到木酮糖的转化率在pH条件下高达86%，这对于XI活性而言是次优的。这些初步发现可以针对工业条件进行优化，具有通过SIF方法提高木糖乙醇产量的巨大潜力。

BACKGROUND & AIMS: :In this study, cellulose hydrolysis activity of two mixed bacterial consortia (NS and QS) was investigated. Combination of NS culture and BHM medium exhibited better hydrolytic activity under the optimal condition of 35 degrees C, initial pH 7.0, and 100rpm agitation. The NS culture could hydrolyze carboxymethyl cellulose (CMC), rice husk, bagasse and filter paper, among which CMC gave the best hydrolysis performance. The CMC hydrolysis efficiency increased with increasing CMC concentration from 5 to 50g/l. With a CMC concentration of 10g/l, the total reducing sugar (RS) production and the RS producing rate reached 5531.0mg/l and 92.9mg/l/h, respectively. Furthermore, seven H2-producing bacterial isolates (mainly Clostridium species) were used to convert the cellulose hydrolysate into H2 energy. With an initial RS concentration of 0.8g/l, the H2 production and yield was approximately 23.8ml/l and 1.21mmol H2/g RS (0.097mmol H2/g cellulose), respectively.

背景与目标： : 在这项研究中，研究了两个混合细菌群落 (NS和QS) 的纤维素水解活性。在35 ℃，初始pH 7.0和100rpm搅拌的最佳条件下，NS培养物和BHM培养基的组合表现出更好的水解活性。NS培养物可以水解羧甲基纤维素 (CMC)，稻壳，蔗渣和滤纸，其中CMC的水解性能最佳。CMC水解效率随着CMC浓度从5增加到50g/l而增加。CMC浓度为10g/l时，总还原糖 (RS) 产量和RS产量分别达到5531.0mg/l和92.9mg/l/h。此外，使用七个H2-producing细菌分离物 (主要是梭状芽孢杆菌属) 将纤维素水解产物转化为H2能量。初始RS浓度为0.8g/l时，H2产量和产率分别约为23.8毫升/l和1.21mmol H2/g RS (0.097mmol H2/g纤维素)。

BACKGROUND & AIMS: :The development of more productive strains of microorganisms and processes that increase enzyme levels can contribute to the economically efficient production of second generation ethanol. To this end, cellulases and xylanases were produced with the S1M29 mutant strain of Penicillium echinulatum, using different concentrations of cellulose (20, 40, and 60 g L(-1)) in batch and fed-batch processes. The highest activities of FPase (8.3 U mL(-1)), endoglucanases (37.3 U mL(-1)), and xylanases (177 U mL(-1)) were obtained in fed-batch cultivation with 40 g L(-1) of cellulose. The P. echinulatum enzymatic broth and the commercial enzyme Cellic CTec2 were tested for hydrolysis of pretreated sugar cane bagasse. Maximum concentrations of glucose and xylose were achieved after 72 h of hydrolysis. Glucose yields of 28.0% and 27.0% were obtained using the P. echinulatum enzymatic extract and Cellic CTec2, respectively.

背景与目标： : 开发更具生产力的微生物菌株和提高酶水平的工艺可以有助于经济高效地生产第二代乙醇。为此，在分批和补料分批过程中，使用不同浓度的纤维素 (20、40和60g L(-1))，用棘青霉的S1M29突变菌株生产纤维素酶和木聚糖酶。在用40g L(-1) 纤维素补料分批培养中获得最高的FPase (8.3 U mL(-1)) 、内切葡聚糖酶 (37.3 U mL(-1)) 和木聚糖酶 (177 U mL(-1)) 活性。测试了棘皮草酶肉汤和商业酶Cellic CTec2对预处理的甘蔗渣的水解作用。水解72小时后达到最大浓度的葡萄糖和木糖。分别使用棘皮草酶提取物和Cellic CTec2获得28.0% 和27.0% 的葡萄糖产量。

BACKGROUND & AIMS: :Female entertainment workers (FEWs) in China are at increased risk of HIV and other sexually transmitted infections, but correlates of their risky sexual behaviour remain poorly understood. Using data from a series of four surveys, this paper employs repeated measures analysis to identify individual and social correlates of consistent condom use among FEWs in Shanghai. Results reveal that both individual cognitive and social influence factors are statistically significant in their bivariate relationships to consistent condom use with a stable or non-stable partner; only prevention motivation and perceived self-efficacy in condom use remain significant in the multiple regressions. When individual and social correlates are examined together, only peer support for condom use remains a significant and independent correlate of consistent condom use in sex with a non-stable partner. Behavioural intervention is urgently needed and should take a multilevel approach, emphasizing individual prevention motivation and behavioural skills training and promoting peer/social support.

背景与目标： : 中国的女性娱乐工作者 (few) 感染艾滋病毒和其他性传播感染的风险增加，但对其危险性行为的相关性仍知之甚少。本文利用四项调查的数据，采用重复措施分析，以识别上海few中持续使用安全套的个人和社会相关性。结果表明，个体认知和社会影响因素在与稳定或非稳定伴侣一致使用安全套的双变量关系中具有统计学意义; 在多元回归中，只有预防动机和安全套使用中的自我效能感仍然显着。当将个人和社会相关性一起检查时，只有同伴对避孕套使用的支持仍然是与不稳定伴侣在性行为中一致使用避孕套的重要且独立的相关性。迫切需要行为干预，并应采取多层次的方法，强调个人预防动机和行为技能培训，并促进同伴/社会支持。

BACKGROUND & AIMS: :Catch crop candidates (corn, guinea grass) for recovering nutrients from farm soil and aquatic plants (water caltrop, water hyacinth) were utilized to produce L-lactic acid. The efficiencies ofpre-treatment methods for enzymatic saccharification and L-lactate production of two fermentation processes, thermophilic simultaneous saccharification and fermentation (SSF), as well as separate saccharification and fermentation, were compared. Conditions were set at 55 degrees C and pH 5.5 for non-sterile fermentation. Alkaline/peroxide pre-treatment proved the most effective for saccharification in pre-treated corn, guinea grass, water caltrop and water hyacinth with glucose yields of 0.23, 0.20, 0.11 and 0.14 g/g-dry native biomass (24-hour incubation period), respectively. Examination of the two types of thermophilic L-lactate fermentation employed following alkaline/peroxide pre-treatment and saccharification demonstrated that the L-lactate yield obtained using SSF (0.15 g/g in the case of corn) was lower than that obtained using separate saccharification and fermentation (0.28 g/g in the case of corn). The lower yield obtained from SSF is likely to have resulted from the saccharification conditions used in the present study, as the possibility of cellulase deactivation during SSF by thermophilic L-lactate producing bacteria existed. A cellulase that retains high activity levels under non-sterile conditions and a L-lactate producer without cellulose hydrolysis activity would be required in order for SSF to serve as an effective method of L-lactate production.

背景与目标： : 用于从农场土壤和水生植物 (水caltrop，水葫芦) 中回收养分的农作物候选物 (玉米，几内亚草) 用于生产L-乳酸。比较了嗜热同时糖化和发酵 (SSF) 以及单独糖化和发酵两种发酵过程的酶促糖化和L-乳酸生产预处理方法的效率。将非无菌发酵的条件设定在55 ℃ 和pH 5.5。碱性/过氧化物预处理被证明对经预处理的玉米，豚草，水caltrop和水葫芦的糖化最有效，葡萄糖产量分别为0.23，0.20，0.11和0.14g/g干天然生物质 (24小时孵育期)。对碱性/过氧化物预处理和糖化后使用的两种嗜热L-乳酸发酵的检查表明，使用SSF获得的L-乳酸产量 (玉米为0.15g/g) 低于使用单独糖化和发酵获得的L-乳酸产量 (在该情况下为0.28g/g) 玉米)。从SSF获得的较低产量可能是由于本研究中使用的糖化条件所致，因为存在嗜热L-乳酸产生细菌在SSF期间纤维素酶失活的可能性。为了使SSF用作生产L-乳酸的有效方法，将需要在非无菌条件下保持高活性水平的纤维素酶和无纤维素水解活性的L-乳酸生产者。

BACKGROUND & AIMS: :To achieve high time-space efficiency for sophorolipid production with yeast Candida bombicola, a strategy of high cell density fermentation was employed. The approach consisted of two sequential stages: (1) the optimization of the carbon source and the nutrient concentration to achieve the maximal cell density and (2) the computer-aided adjustment of physical parameters and the controlled feeding of substrates for enhanced volumetric productivity. Both stages have been successfully implemented in a 10-L fermenter, where up to 80 g dry cell weight/L was obtained and a remarkably high volumetric productivity (> 200 g isolated sophorolipids/L/day) was achieved. Both the biomass and volumetric productivity were markedly higher than previously reported. Specifically, the high productivity of sophorolipids could be attained on a very short time scale (24 h), highlighting the industrial potential of the platform developed in this work.

背景与目标： : 为了实现酵母念珠菌生产槐糖脂的高时空效率，采用了高细胞密度发酵策略。该方法包括两个连续的阶段 :( 1) 优化碳源和养分浓度以实现最大细胞密度; (2) 计算机辅助调节物理参数和受控进料底物以提高体积生产率。这两个阶段都已在10-l发酵罐中成功实施，其中获得了高达80 g的干细胞重量/L，并且实现了非常高的体积生产率 (> 200g分离的槐糖脂/L/天)。生物量和体积生产率均明显高于先前报道的水平。具体来说，可以在非常短的时间范围内 (24小时) 实现槐糖脂的高生产率，这突显了在这项工作中开发的平台的工业潜力。

BACKGROUND & AIMS: :Four types of neutral glycosphingolipids (LacCer, Gb3Cer, Gb4Cer, and IV3αGalNAc-Gb4Cer; 10 pmol each) were analyzed using high-performance liquid chromatography (HPLC)-electrospray ionization quadrupole ion trap time-of-flight (ESI-QIT-TOF) mass spectrometry (MS) with a repeated high-speed polarity and MSn switching system. This system can provide six types of mass spectra, including positive and negative ion MS, MS2, and MS3 spectra, within 1 s per cycle. Using HPLC with a normal-phase column, information on the molecular weights of major molecular species of four neutral glycosphingolipids was obtained by detecting [M+Na]+ in the positive ion mode mass spectra and [M−H]− in the negative ion mode mass spectra. Sequences of glycosphingolipid oligosaccharide were obtained in the negative ion MS2 spectra. In addition, information on the ceramide structures was clearly obtained in the negative ion MS3 mass spectra. GlcCer molecular species were analyzed by HPLC-ESI-QIT-TOF MS with a reversed-phase column using 1 pmole of GlcCer. The structures of the seven molecular species of GlcCer, namely, d18:1-C16:0, d18:1-C18:0, d18:1-C20:0, d18:1-C22:0, d18:1-C23:0, d18:1-C24:1, and d18:1-C24:0, were characterized using positive ion MS and negative ion MS, MS2, and MS3. The established HPLC-ESI-QIT-TOF MS with MSn switching and a normal phase column has been successfully applied to the structural characterization of LacCer and Gb4Cer in a crude mixture prepared from human erythrocytes.

背景与目标： : 四种类型的中性鞘糖脂 (LacCer，Gb3Cer，Gb4Cer和IV3αGalNAc-Gb4Cer; 使用高效液相色谱 (HPLC)-电喷雾电离四极杆离子阱飞行时间 (ESI-qit-tof) 质谱 (MS) 分析，并具有重复的高速极性和MSn切换系统。该系统可以在每个周期1 s内提供六种类型的质谱，包括正负离子MS，MS2和MS3光谱。使用带有正相色谱柱的HPLC，通过在正离子模式质谱中检测 [M Na] 和在负离子模式质谱中检测 [M-h]-，获得了有关四种中性鞘糖脂的主要分子种类的分子量的信息。在负离子MS2光谱中获得了鞘糖脂寡糖序列。此外，在负离子MS3质谱中清楚地获得了有关神经酰胺结构的信息。GlcCer分子种类通过hplc-esi-QIT-TOF MS用反相色谱柱使用1 pmole的GlcCer进行分析。GlcCer的七个分子物种的结构，即d18:1-C16:0，d18:1-C18:0，d18:1-C20:0，d18:1-C22:0，d18:1-C23:0，d18:1-C24:1和d18:1-C24:0，使用正离子MS和负离子MS，MS2和ms3进行表征。建立的具有MSn切换和正相柱的hplc-esi-QIT-TOF MS已成功应用于由人红细胞制备的粗混合物中LacCer和Gb4Cer的结构表征。

BACKGROUND & AIMS: :The effects of pre-treatment methods on saccharification and hydrogen fermentation of Chlorella pyrenoidosa biomass were investigated. When raw biomass and biomass pre-treated by steam heating, by microwave heating, and by ultrasonication were used as feedstock, the hydrogen yields were only 8.8-12.7 ml/g total volatile solids (TVS) during dark fermentation. When biomass was pre-treated by steam heating with diluted acid and by microwave heating with diluted acid, the dark hydrogen yields significantly increased to 75.6 ml/g TVS and 83.3 ml/g TVS, respectively. Steam heating with diluted acid is the preferred pre-treatment method of C. pyrenoidosa biomass to improve hydrogen yield during dark fermentation and photofermentation, which is followed by methanogenesis to increase energy conversion efficiency (ECE). A total hydrogen yield of 198.3 ml/g TVS and a methane yield of 186.2 ml/g TVS corresponding to an overall ECE of 34.0% were obtained through the three-stage process (dark fermentation, photofermentation, and methanogenesis).

背景与目标： : 研究了预处理方法对小球藻生物质糖化和氢发酵的影响。当使用通过蒸汽加热，通过微波加热和通过超声处理的原始生物质和生物质作为原料时，在黑暗发酵期间，氢产率仅为8.8-12.7毫升/g总挥发性固体 (TVS)。当通过用稀酸进行蒸汽加热和用稀酸进行微波加热对生物质进行预处理时，暗氢产量分别显著增加至75.6毫升/g TVS和83.3毫升/g TVS。用稀酸蒸汽加热是C. pyrenoidosa生物质的首选预处理方法，以提高黑暗发酵和光发酵过程中的氢产量，随后是甲烷生成以提高能量转化效率 (ECE)。通过三阶段过程 (暗发酵、光发酵和产甲烷) 获得了198.3毫升/g TVS的总氢产率和186.2毫升/g TVS的甲烷产率，对应于34.0% 的总ECE。

BACKGROUND & AIMS: :Repeated exposure to a moderately intense stressor typically produces attenuation of the hypothalamic-pituitary-adrenal (HPA) axis response (habituation) on re-presentation of the same stressor; however, if a novel stressor is presented to the same animals, the HPA axis response may be augmented (sensitization). The extent to which this adaptation is also evident within neural activity patterns is unknown. This study tested whether repeated ferret odor (FO) exposure, a moderately intense psychological stressor for rats, leads to both same-stressor habituation and novel-stressor sensitization of the HPA axis response and neuronal activity as determined by immediate early gene induction (c-fos mRNA). Rats were presented with FO in their home cages for 30 min a day for up to 2 wk and subsequently challenged with FO or restraint. Rats displayed HPA axis activity habituation and widespread habituation of c-fos mRNA expression (in situ hybridization) throughout the brain in as few as three repeated presentations of FO. However, repeated FO exposure led to a more gradual development of sensitized HPA-axis and c-fos mRNA responses to restraint that were not fully evident until after 14 d of prior FO exposure. The sensitized response was evident in many of the same brain regions that displayed habituation, including primary sensory cortices and the prefrontal cortex. The shared spatial expression but distinct temporal development of habituation and sensitization neural response patterns suggests two independent processes with opposing influences across overlapping brain systems.

背景与目标： : 反复暴露于中等强度的应激源通常会在重新呈现相同的应激源时导致下丘脑-垂体-肾上腺 (HPA) 轴反应 (习惯) 的减弱; 但是，如果向同一动物呈现一种新型的应激源，则可能会增强HPA轴反应 (敏化)。在神经活动模式中这种适应的程度也很明显是未知的。这项研究测试了反复暴露的雪貂气味 (FO) (一种中等强度的大鼠心理压力源) 是否会导致HPA轴反应和神经元活动的相同压力源习惯和新压力源敏化 (由立即的早期基因诱导确定) (c-fos mRNA)。每天在家养中给大鼠30分钟的FO，最多2周，然后用FO或约束对大鼠进行攻击。大鼠在整个大脑中显示出HPA轴活动的习惯性和c-fos mRNA表达的广泛习惯性 (原位杂交)，其中只有三个重复的FO表现。然而，反复的FO暴露导致致敏的HPA轴和c-fos mRNA对约束的反应逐渐发展，直到先前的FO暴露14 d后才完全明显。在许多表现出习惯性的相同大脑区域 (包括初级感觉皮层和前额叶皮层) 中，敏化反应都很明显。习惯和敏化神经反应模式的共享空间表达但时间上的不同发展表明，两个独立的过程在重叠的大脑系统中具有相反的影响。

BACKGROUND & AIMS: :Ethanol fermentation from sweet sorghum juice containing 240 g/l of total sugar by Saccharomyces cerevisiae TISTR 5048 and S. cerevisiae NP 01 immobilized on low-cost support materials, corncob pieces, was investigated. In batch fermentation, S. cerevisiae TISTR 5048 immobilized on 6 × 6 × 6 mm(3) corncobs gave higher ethanol production than those immobilized on 12 × 12 × 12 mm(3) corncobs in terms of ethanol concentration (P), yield (Y ( p/s )) and productivity (Q ( p )) with the values of 102.39 ± 1.11 g/l, 0.48 ± 0.01 and 2.13 ± 0.02 g/l h, respectively. In repeated-batch fermentation, the yeasts immobilized on the 6 × 6 × 6 mm(3) corncobs could be used at least eight successive cycles with the average P, Y ( p/s ) and Q ( p ) of 97.19 ± 5.02 g/l, 0.48 ± 0.02 and 2.02 ± 0.11 g/l h, respectively. Under the same immobilization and repeated-batch fermentation conditions, P (90.75 ± 3.05 g/l) and Q ( p ) (1.89 ± 0.06 g/l h) obtained from S. cerevisiae NP 01 were significantly lower than those from S. cerevisiae TISTR 5048 (P < 0.05), while Y ( p/s ) from both strains were not different. S. cerevisiae TISTR 5048 immobilized on the corncobs also gave significantly higher P, Y ( p/s ) and Q ( p ) than those immobilized on calcium alginate beads (P < 0.05).

背景与目标： : 研究了固定在低成本支持材料玉米芯上的酿酒酵母TISTR 5048和酿酒酵母NP 01从含有240g/l总糖的甜高粱汁中进行的乙醇发酵。在分批发酵中，就乙醇浓度 (P) 而言，固定在6 × 6毫米 (3) 玉米芯上的酿酒酵母5048的乙醇产量高于固定在12 × 12毫米 (3) 玉米芯上的乙醇产量，产量 (Y ( p/s )) 和生产率 (Q ( p )) 分别为102.39 ± 1.11g/l，0.48 ± 0.01和2.13 ± 0.02g/l h。在重复分批发酵中，固定在6 × 6毫米 (3) 玉米芯上的酵母可以连续使用至少八个循环，平均P，Y (p/s) 和Q (p) 为97.19 ± 5.02g/l，分别为0.48 ± 0.02和2.02 ± 0.11g/l h。在相同的固定化和重复分批发酵条件下，酿酒酵母NP 01的P (90.75 ± 3.05g/l) 和Q (p ) (1.89 ± 0.06g/l h) 明显低于酿酒酵母5048 (P <0.05)，而两种菌株的Y (p/s) 没有不同。固定在玉米芯上的酿酒酵母 (S. cerevisiae TISTR) 5048也比固定在藻酸钙珠上的P，Y (p/s) 和Q (p) 明显更高 (P <0.05)。

BACKGROUND & AIMS: :The study investigated effect of high influent nitrate concentration on poly-beta-hydroxybutyrate, (PHB), storage in a sequencing batch reactor, (SBR), under anoxic conditions. Acetate was fed as pulse during anoxic phase, sustained with external nitrate feeding. SBR operation involved three runs at steady state with COD/N ratios of 3.84, 2.93 and 1.54 gCOD/gN, where external nitrate concentrations gradually increased from 50 mg N/l to 114 mg N/l and 226 mg N/l, in 1st, 2nd and 3rd runs, respectively. In 1st run, acetate was fully converted into PHB with the storage yield value of 0.57-0.59 gCOD/gCOD, calculated both in terms of PHB formation and NO(X) utilization, confirming storage was the sole substrate utilization mechanism. In the following runs, PHB formation was reduced and the storage yield based on PHB dropped down to 0.40 and 0.33 gCOD/gCOD with increasing influent nitrate concentrations, indicating that higher portions of acetate were diverted to simultaneous direct growth. The observations suggested that nitrite accumulation detected at low COD/N ratios was responsible for inhibition of PHB storage.

背景与目标： : 该研究调查了高进水硝酸盐浓度对在缺氧条件下在序批式反应器 (SBR) 中储存的聚-β-羟基丁酸酯 (PHB) 的影响。在缺氧阶段将乙酸盐作为脉冲饲喂，并通过外部硝酸盐饲喂维持。SBR操作涉及稳态下的三次运行，COD/N比为3.84、2.93和1.54 gCOD/gN，其中外部硝酸盐浓度在第一、第二和第三次运行中分别从50 mg N/l逐渐增加到114 mg N/l和226 mg N/l。在第一个运行中，乙酸盐完全转化为PHB，储存产量值为0.57-0.59 gCOD/gCOD，根据PHB形成和NO(X) 利用率计算，确认储存是唯一的底物利用机制。在接下来的运行中，PHB形成减少，基于PHB的储存产量下降到0.40，并且随着进水硝酸盐浓度的增加0.33 gCOD/gCOD，表明较高部分的乙酸盐被转移到同时直接生长。观察结果表明，在低COD/N比下检测到的亚硝酸盐积累是抑制PHB储存的原因。

BACKGROUND & AIMS: :Fish sauce production relies on a natural fermentation process requiring 12-18 months for process completion. Virgibacillus sp. SK37 has been shown to be a potential strain for fish sauce acceleration. However, hydrolytic activity of proteinases bound at cell surface of this strain has not been well elucidated. Addition of 0.2 % CaCl(2) (w/w) in conjunction with starter cultures of Virgibacillus sp. SK 37 increased protein hydrolysis as measured by α-amino group content throughout fermentation (P < 0.05). Cell-bound proteinases from Virgibacillus sp. SK 37 were extracted into a free form by incubating the washed cells in Ca(2+)-free buffer at 37 °C for 2 h. Cell-bound proteinases revealed molecular mass of 19, 20, 22, 32, 34, and 44 kDa based on a synthetic peptide zymogram. The proteinases showed subtilisin-like serine characteristics with the highest activity at 50 °C and pH 8 and 11. Activity of the extracted proteinases increased ~4 times at ≥100 mM CaCl(2). In addition, CaCl(2) enhanced thermal stability of the extracted proteinases. Enzymes showed proteolytic activity in either the absence or presence of 10 and 25 % NaCl toward fish muscle, soy protein isolate, and casein substrates. Cell-bound proteinases were likely to play an important role in protein hydrolysis during fish sauce fermentation.

背景与目标： : 鱼露生产依赖于自然发酵过程，需要12-18个月才能完成过程。Virgibacillus sp。SK37已被证明是鱼露加速的潜在菌株。然而，尚未很好地阐明该菌株细胞表面结合的蛋白酶的水解活性。添加0.2% CaCl(2) (w/w) 与Virgibacillus sp. SK 37的发酵剂培养物一起增加了蛋白质水解，如在整个发酵过程中通过 α-氨基含量测量 (P <0.05)。通过将洗涤过的细胞在不含Ca(2) 的缓冲液中于37 °C孵育2小时，将来自Virgibacillus sp. SK 37的细胞结合蛋白酶提取为游离形式。根据合成肽酶谱，细胞结合蛋白酶的分子量为19、20、22、32、34和44 kDa。蛋白酶表现出枯草杆菌蛋白酶样丝氨酸特征，在50 °C和pH 8和11时活性最高。提取的蛋白酶的活性在 ≥ 100 mM CaCl(2) 时增加了约4倍。此外，CaCl(2) 增强了提取的蛋白酶的热稳定性。在不存在或存在10和25% NaCl的情况下，酶对鱼肌肉，大豆分离蛋白和酪蛋白底物表现出蛋白水解活性。在鱼露发酵过程中，细胞结合的蛋白酶可能在蛋白质水解中起重要作用。

BACKGROUND & AIMS: :This study endeavored to investigate the diversity of microbes present during the shaping, ripening and drying of Daqu, a fermentation starter culture and substrata complex of Maotai alcoholic spirit. A nested PCR-denaturing gradient gel electrophoresis technique was utilized with different combinations of primers. The results showed the presence of bacteria, yeasts and molds. The microflora, which originate from wheat, were readily detectable during every stage of the fermentation process. However, the microbial structure had clear differences in the shaping, ripening and drying processes. In the shaping stage, there was a high level of diversity of the LAB (lactic acid bacteria) and fungi in the shaped samples. In the ripening stage, however, a reduction of diversity of fungi with a high level of diversity of the Bacilli was observed in the ripened samples. In the drying stage, the diversity of Bacilli and fungi, especially acid-producing bacteria, reduced dramatically. Interestingly, uncultured Lactococcus sp., Microbacterium testaceum, Cochliobolus sp., and Thermoascus crustaceus were the first to be detected in the fermentation starters used in liquor production. This study revealed the microbial diversity and distributions during the shaping, ripening and drying of Daqu-making, facilitating evaluation of the hygienic conditions and aiding in the design of specific starter and/or adjunct cultures.

背景与目标： : 本研究致力于研究茅台酒精发酵发酵剂和基质复合物大曲的成型，成熟和干燥过程中存在的微生物多样性。将巢式PCR变性梯度凝胶电泳技术与不同的引物组合一起使用。结果表明存在细菌，酵母和霉菌。在发酵过程的每个阶段都很容易检测到源自小麦的微生物区系。然而，微生物结构在成型，成熟和干燥过程中存在明显差异。在成型阶段，成型样品中实验室 (乳酸菌) 和真菌的多样性很高。然而，在成熟阶段，在成熟的样品中观察到真菌多样性的减少以及细菌的高水平多样性。在干燥阶段，细菌和真菌，尤其是产酸细菌的多样性急剧减少。有趣的是，未培养的乳球菌属，微细菌testaceum，Cochliobolus sp。和甲壳纲Thermoascus是在白酒生产中使用的发酵发酵剂中首次检测到的。这项研究揭示了大曲成型，成熟和干燥过程中的微生物多样性和分布，有助于评估卫生条件，并有助于设计特定的发酵剂和/或辅助培养物。

BACKGROUND & AIMS: :Denitrification and arginine fermentation are major parts of the anaerobic metabolism of Pseudomonas aeruginosa, which is important for biofilm formation and infection. The two-component regulatory system NarX-NarL is part of the underlying network and is required for denitrifying growth. All target promoters identified so far are activated by NarL. In this study the effect of NarL on arginine fermentation was investigated using proteome, Northern blot and lacZ reporter gene analyses. NarL-dependent repression of the arcDABC operon was observed and the corresponding NarL-binding site in the arcD promoter region was functionally localized at -60 bp upstream of the transcriptional start site using site-directed promoter mutagenesis and reporter gene fusion experiments. The results clearly show that in the presence of nitrate NarL represses the arginine-dependent activation of the arcDABC operon mediated by ArgR. It does not influence the oxygen-tension-dependent activation via Anr. Thus, the anaerobic energy metabolism of P. aeruginosa is coordinated via NarX-NarL activity. In the presence of nitrate the highly efficient denitrification is preferred over the less attractive arginine fermentation.

背景与目标： : 反硝化和精氨酸发酵是铜绿假单胞菌厌氧代谢的主要组成部分，对生物膜的形成和感染具有重要意义。两部分监管系统narx-narl是基础网络的一部分，是反硝化增长所必需的。到目前为止，所有鉴定的靶启动子都被NarL激活。在这项研究中，使用蛋白质组，Northern印迹和lacZ报告基因分析研究了NarL对精氨酸发酵的影响。使用定点启动子诱变和报告基因融合实验，观察到arcDABC操纵子的NarL依赖性抑制，并且arcD启动子区域中相应的NarL结合位点功能定位在转录起始位点上游-60 bp。结果清楚地表明，在存在硝酸盐的情况下，NarL抑制arcDABC操纵子的精氨酸依赖性激活。它不会通过Anr影响氧张力依赖性激活。因此，铜绿假单胞菌的厌氧能量代谢是通过NarX-NarL活性协调的。在硝酸盐存在下，与吸引力较小的精氨酸发酵相比，高效的反硝化作用是优选的。

BACKGROUND & AIMS: :Agmatine, an endogenous amine derived from decarboxylation of L-arginine catalyzed by arginine decarboxylase, has been proposed as a neurotransmitter or neuromodulator in the brain. In the present study, we examined whether agmatine has neuroprotective effects against repeated immobilization-induced morphological changes in brain tissues and possible effects of immobilization stress on endogenous agmatine levels and arginine decarboxylase expression in rat brains. Sprague-Dawley rats were subjected to 2h immobilization stress daily for 7 days. This paradigm significantly increased plasma corticosterone levels, and the glutamate efflux in the hippocampus as measured by in vivo microdialysis. Immunohistochemical staining with beta-tubulin III showed that repeated immobilization caused marked morphological alterations in the hippocampus and medial prefrontal cortex that were prevented by simultaneous treatment with agmatine (50mg/kg/day), i.p.). Likewise, endogenous agmatine levels measured by high-performance liquid chromatography in the prefrontal cortex, hippocampus, striatum and hypothalamus were significantly increased by immobilization, as compared to controls. The increased endogenous agmatine levels, ranging from 92 to 265% of controls, were accompanied by a significant increase of arginine decarboxylase protein levels in the same regions. These results demonstrate that the administration of exogenous agmatine protects the hippocampus and medial prefrontal cortex against neuronal insults caused by repeated immobilization. The parallel increase in endogenous brain agmatine and arginine decarboxylase protein levels triggered by repeated immobilization indicates that the endogenous agmatine system may play an important role in adaptation to stress as a potential neuronal self-protection mechanism.

背景与目标： : Agmatine是一种内源性胺，由精氨酸脱羧酶催化的L-精氨酸脱羧衍生而来，已被提议作为大脑中的神经递质或神经调节剂。在本研究中，我们检查了agmatine是否对反复固定诱导的脑组织形态学变化具有神经保护作用，以及固定应激对大鼠脑中内源性agmatine水平和精氨酸脱羧酶表达的可能影响。Sprague-Dawley大鼠每天进行2小时的固定应激7天。通过体内微透析测量，这种范例显着增加了血浆皮质酮水平和海马中的谷氨酸外排。用 β-微管蛋白III进行的免疫组织化学染色显示，反复固定会导致海马和内侧前额叶皮层发生明显的形态学改变，而同时用agmatine (50 mg/kg/天) 进行治疗则可以防止这种改变。同样，与对照组相比，通过固定，通过高效液相色谱法测量的前额叶皮层，海马，纹状体和下丘脑中的内源性agmatine水平显着增加。增加的内源性苯丙胺水平 (从92到265% 的对照范围) 伴随着相同区域中精氨酸脱羧酶蛋白水平的显着增加。这些结果表明，外源性agmatine的给药可保护海马和内侧前额叶皮层免受反复固定引起的神经元损伤。反复固定化引发的内源性脑agmatine和精氨酸脱羧酶蛋白水平平行升高，表明内源性agmatine系统可能作为一种潜在的神经元自我保护机制在适应压力方面发挥重要作用。