金属离子对红霉素合成及组分转化的影响及机理分析

目的研究Co2+、Zn2+和Na2MoO43种金属离子对糖多孢红霉菌发酵生产红霉素及组分转化的影响,并对其影响机理进行相关分析。方法通过摇瓶实验确定金属离子最优配比,并在15L发酵罐上放大;通过菌体在合成培养基中的摇瓶发酵研究红霉素合成途径中羟基化基因eryK、甲基化基因eryG的表达量与红霉素合成及组分转化的关系。结果 3种金属离子的添加使红霉素发酵单位由对照罐8433U/mL提高到11858U/mL,有效组分ErA由对照83.6%提高到89%;eryK和eryG两种基因的表达量显著提高,且eryK/eryG比值与有效组分ErA含量具有较好的相关性。结论 3种金属离子能通过调节菌种相关基因的表达,对红霉素的合成及组分转化产生促进作用。

不同有机酸对石灰性土壤磷的活化效应及机理

【目的】添加低分子量有机酸是活化土壤难溶性磷有效途径。比较研究几种低分子量有机酸及其组合对土壤磷的活化性能,为土壤磷的高效利用提供依据。【方法】低磷和高磷石灰性土壤选自新疆石河子,设置5个低分子有机酸添加处理:草酸、柠檬酸、黄腐酸、柠檬酸+草酸、草酸+柠檬酸+黄腐酸处理,和一个0.01mmol/L KCl对照。采用吸附平衡实验法测定土壤磷的吸附量;采用土壤吸附动力学实验法测定土壤磷的解吸动力学。采用常规和灭菌土壤培养方法,通过连续浸提法研究低分子有机酸及其组合对磷组分动态转化的影响和pH对磷的活化效应。【结果】Langmuir与Elovich模型均可较好地拟合土壤对磷的吸附热力学(R^(2)=0.852~0.994)与吸附动力学过程(R^(2)=0.882~0.975)。低磷土壤的最大吸附量(Q_(max))、最大缓冲容量(MBC)、吸附力常数(K_L)和吸附速率(b)均高于高磷土壤,表明低磷土壤对磷的吸附更强。低分子量有机酸添加均降低了Q_(max)、MBC和b。草酸对Q_(max)和MBC的降幅最大,低磷土壤降幅分别为28.5%和74.9%,高磷土壤分别为14.7%和73.3%。柠檬酸对低磷土壤的b值降幅最大(80.9%),草酸对高磷土壤的b值降幅最大(22.0%)。与CK相比,草酸添加显著提高了Olsen-P含量,草酸+柠檬酸效果次之,黄腐酸对磷的活化效果最差。不灭菌培养条件下,草酸和草酸+柠檬酸处理低磷土壤的Olsen-P含量分别增加了42.6%和18.5%,高磷土壤分别增加了27.3%和1.01%;草酸和草酸+柠檬酸处理的活性磷组分Resin-P在低磷土壤中分别增加了80.9%和77.4%,在高磷土壤中分别增加了79.5%和72.8%;非活性磷组分Di HCl-P在低磷土壤中分别降低了8.87%和5.89%,在高磷土壤中分别降低了8.83%和5.54%;Con HCl-P在低磷土壤中分别降低了25.1%和12.9%,在高磷土壤中分别降低了16.9%和5.30%。柠檬酸处理的Resin-P在低磷和高磷土壤中分别增加了70.2%和79.5%,而NaOH-P则分别降低了14.8%、26.3%,说明草酸、草酸+柠檬酸促进了非活性磷向活性磷组分的转化,柠檬酸则促进了中活性磷向活性磷组分的转化。土壤灭菌培养各处理磷组分含量与不灭菌培养无显著差异,说明微生物对有机酸活化土壤磷的效应无显著影响。不论是否灭菌,土壤Olsen-P含量的增加与pH降低呈负相关,因此致酸效应不是小分子有机酸活化土壤难溶性磷的主要机制。【结论】小分子有机酸通过与磷竞争吸附位点或进行螯合反应活化土壤磷,而不是通过致酸效应或激发磷活化相关的微生物。3种小分子有机酸相比,草酸活化磷的效果最大,其次是柠檬酸、黄腐酸,单一有机酸的活化效果大于有机酸组合。

淹水对石灰性土壤无机磷形态转化的影响

【目的】磷肥施入土壤后大部分转化为与铁氧化物关系密切的Fe-P和O-P,而淹水后土壤中铁的氧化还原过程可能影响与铁氧化物结合的磷的形态及有效性的变化。研究不同施磷处理下淹水土壤Fe(II)、无机磷组分等的变化,以期明确淹水后土壤无机磷形态及磷有效性变化及其与铁氧化还原过程的关系。【方法】用不施磷土壤(P0)和连续6年施用P 180 kg/hm^(2)的土壤(P180)进行室内模拟培养试验。将土壤装于西林瓶内,加水模拟淹水条件,西林瓶密封后,分别在避光或者光照条件下,于(30±1)℃恒温培养40天。测定供试土壤以及淹水培养土壤中的速效磷、无机磷以及不同形态无机磷组分含量,测定培养过程Fe(II)的动态变化,以探讨磷形态转化与铁氧化还原过程的关系。【结果】施用磷肥显著增加土壤中的速效磷含量和无机磷总量,P0处理土壤速效磷含量为(7.65±1.65)mg/kg,P180处理土壤速效磷含量高达(33.5±2.01)mg/kg。施入土壤中的磷只有很小部分以Ca_(2)-P存在,主要以Ca_(10)-P、Ca_(8)-P、Al-P和Fe-P形态存在。避光淹水培养后,土壤速效磷含量增加,P0和P180处理土壤速效磷含量的增量分别为8.44、2.95 mg/kg。淹水培养降低了土壤Ca_(8)-P含量,提升了Fe-P、O-P、Al-P含量。光照和避光条件下P180处理土壤中Ca_(8)-P含量分别降低106.8、156.2 mg/kg,Fe-P含量分别增加23.4、47.0 mg/kg,O-P含量分别增加64.1、92.9 mg/kg,Al-P含量分别增加38.8、34.7 mg/kg,避光时Ca_(8)-P降幅以及Fe-P和O-P的增量均大于光照条件下。避光条件下,铁还原量和还原最大速率与Ca_(8)-P变化量之间存在显著负相关关系,与Fe-P、O-P增量之间存在显著正相关关系。【结论】淹水条件下,石灰性土壤中的Fe(Ⅲ)还原形成Fe(Ⅱ)和Fe(Ⅲ)混合物,增加了铁氧化物的比表面积和磷吸附点,可促进Ca_(8)-P向O-P、Fe-P和Al-P转化。光照降低了Fe(Ⅲ)的还原量,可能是Ca_(8)-P向O-P、Fe-P和Al-P转化率低的原因之一。

阻燃水性带锈涂料研究

介绍一种通过转化组分、成膜组分和助剂组分接技改性研制而成的涂料。它籍着化学作用将铁锈转化为不再被氧化锈蚀的稳定的配位化合物 ,形成一层的保护性漆膜 ,能抑制再生锈 ,成为金属油漆所需的底漆 ,可以和多种面漆配套使用 ,且为水性阻燃耐高温 ,漆膜耐水耐化学腐蚀。

Expression and significance of homeodomain protein Cdx2 in gastric carcinoma and precancerous lesions

AIM： To investigate the expression and significance of caudal-related homeobox transcription factor （Cdx2） in gastric carcinoma （GC） and precancerous lesions. METHODS： The expression of Cdx2 in GC, precancer- ous lesions and normal gastric mucosa were detected using immunohistochemical method. Hematoxylin and eosin staining, alcian blue/periodic acid-schiff and high iron diamine/alcian blue staining were used to classify intestinal metaplasia （IM） and GC. RESULTS： Cdx2 was not detected in normal gas- tric mucosa. Cdx2 expression was detected in 87.1% （101/116） of IM, 50% （36/72） of dysplasia and 48.2% （41/85） of GC. The Cdx2-expressing cells in IM were more prevalent than in dysplasia and carcinoma （P 〈 0.05）. There was no relationship between Cdx2 ex- pression and the classification of IM or the degree of dysplasia. Expression of Cdx2 was significantly higher in intestinal-type carcinoma than in diffuse and mixed- type carcinoma （P 〈 0.05）. Positive expression of Cdx2was mainly found in moderately to well differentiated GC. There was a negative association between nuclear Cdx2 expression and lymph node metastasis and tumor, nodes, metastasis stage of GC （P 〈 0.05）. The patients with Cdx2-positive expression showed a higher survival rate than those with Cdx2-negative expression （P = 0.038）. Multivariate analysis revealed that the expres- sion of Cdx2 and lymph node metastasis were indepen- dent prognostic indicators of GC （P 〈 0.05）.

Expression of Thyroid Transcription Factor-1(TTF-1)in Lung Carcinomas and Its Correlations with Apoptosis and Angiogenesis

OBJECTIVE To investigate the correlations between the expression of thyroid transcription factor-1 （TTF-1） and apoptosis and angiogenesis in lung carcinomas. METHODS A 829 microarray of the paraffin tissue chips was constructed, which contained 196 lung carcinomas, 10 normal lung tissues, and 1 muscular tissue. Terminal deoxynucleotidyl transferase mediated nick end labeling （TUNEL） and immunohistochemical SP method were used to detect apoptosis and expression of TTF-1 and CD34 in different types of lung carcinomas. A Leica Q500 MC image analysis system was used to measure and calculate TTF-1 positive unit （PU）, apoptotic index （AI） and microvessel density （MVD）. RESULTS AI of lung small cell carcinoma and large cell carcinoma were smaller than those of lung adenocarcinoma and squamous cell carcinoma （P = 0.000）. AI of lung carcinomas with lymph node metastases was smaller than that of those without （P = 0.039）. AI of lung carcinomas in TNM stage I-IV was smaller than that in stage I （P = 0.008）. The PU of the TTF-1 was negatively correlated with AI in small cell lung carcinoma （r = -0.752, P = 0.000）. MVD of lung carcinomas without lymph node metastases was smaller than that of those with lymph node metastasis （P = 0.031）. MVD of lung carcinomas in TNM stage I was smaller than that in stage I-IV （P = 0.040）. The PU of TTF-1 was positively correlated with MVD in lung adenocarcinoma （r = 0.708, P = 0.000）. CONCLUSION There is a negative correlation between TTF-1 PU and AI in small cell lung carcinoma. TTF-1 PU and AI may be correlated with each other. There is a positive correlation between TTF-1 PU and MVD in lung adenocarcinoma. TTF-1 may induce the development of lung adenocarcinoma by inducing tumor angiogenesis.

Silver-catalyzed three-component reaction of phenyldiazoacetate with arylamine and imine

A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silver catalyst.The Lewis acidity of the silver catalyst affected the different types of substrate diastereoselectivities;It also led to the formation of amine‐exchange side products.

2014生物质炼制专刊序言

生物质是自然界最丰富的含碳有机大分子功能体,它有望通过"生物炼制"实现"石油炼制"的辉煌。但是由于生物质资源本身及其转化过程的复杂性,生物质产业虽备受关注,却被认为是遥远的未来产业。传统的生物质资源化利用思路都是先耗费一定的能量破坏生物质结构,然后再进行转化,不仅没有考虑到产品的功能需求,而且过程的原子经济性不高。如何实现化学键更加复杂的固相木质纤维素生物质炼制是实现生物质产业的关键和难点。理想的生物质炼制的目的是以最大得率分离木质纤维原料中各个组分,以尽可能地保持分子的完整性,最大可能地优化利用和最终实现最大价值。这就要求生物质炼制应当是基于原料结构、过程转化和产品特点三者的关联,面向原料、面向过程、面向产品的炼制过程。本期专刊报道了我国生物质炼制技术领域专家学者在原料炼制、炼制技术、组分转化等领域取得的最新研究进展。

Artemisinin mimics calorie restriction to extend yeast lifespan via a dual-phase mode: a conclusion drawn from global transcriptome profiling

Calorie restriction(CR) promotes longevity among distinct organisms from yeast to mammals. Although CR-prolonged lifespan is believed to associate with enhanced respiratory activity, it is apparently controversial for accelerated energy consumption regardless of insufficient nutrient intake. In reconciling the contradiction of less food supply versus much metabolite dispense, we revealed a CR-based mode of dual-phase responses that encompass a phase of mitochondrial enhancement(ME) and a phase of post-mitochondrial enhancement(PME), which can be distinguished by the expression patterns and activity dynamics of mitochondrial signatures. ME is characterized by global antioxidative activation, and PME is denoted by systemic metabolic modulation. CR-mediated aging-delaying effects are replicated by artesunate, a semi-synthetic derivative of the antimalarial artemisinin that can alkylate heme-containing proteins, suggesting artesunate-heme conjugation functionally resembles nitric oxide-heme interaction. A correlation of artesunate-heme conjugation with cytochrome c oxidase activation has been established from adduct formation and activity alteration. Exogenous hydrogen peroxide also mimics CR to trigger antioxidant responses, affect signaling cascades, and alter respiratory rhythms, implying hydrogen peroxide is engaged in lifespan extension. Conclusively, artesunate mimics CR-triggered nitric oxide and hydrogen peroxide to induce antioxidative networks for scavenging reactive oxygen species and mitigating oxidative stress, thereby directing metabolic conversion from anabolism to catabolism, maintaining essential metabolic functionality, and extending life expectancy in yeast.

Recent advances in catalytic production of sugar alcohols and their applications

Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, and erythritol can be potentially used as emerging fuels and chemicals. These sugar alcohols can be converted into widely used products(e.g. polymer synthesis, food and pharmaceuticals industry). The heterogeneous catalytic production of sugar alcohols from renewable biomass provides a safe and sustainable approach. Hydrolysis, coupled with hydrogenation and hydrogenolysis has been proved to be more effective strategy for sugar alcohols production from biomass. This review summarizes the recent advances in biomass upgrading reactions for the production of sugar alcohols and their comprehensive applications.