Biological Synthesis of Size-Controlled Cadmium Sulfide Nanoparticles Using Immobilized Rhodobacter sphaeroides

Size-controlled cadmium sulfide nanoparticles were successfully synthesized by immobilized Rhodobacter sphaeroides in the study. The dynamic process that Cd²⁺ was transported from solution into cell by living R. sphaeroides was characterized by transmission electron microscopy (TEM). Culture time, as an important physiological parameter for R. sphaeroides growth, could significantly control the size of cadmium sulfide nanoparticles. TEM demonstrated that the average sizes of spherical cadmium sulfide nanoparticles were 2.3 ± 0.15, 6.8 ± 0.22, and 36.8 ± 0.25 nm at culture times of 36, 42, and 48 h, respectively. Also, the UV–vis and photoluminescence spectral analysis of cadmium sulfide nanoparticles were performed.     

葛仙米脆粒含浸调理工艺研究

先将葛仙米进行预干燥,再通过真空含浸技术使干燥的葛仙米内部浸入海藻糖、奶油的含浸液,使其具有奶油的香甜口感。最后再次利用干燥,除去含浸后葛仙米内部的水分,最大程度的保持葛仙米的形状和营养成分。首先,确定葛仙米的预干燥方式为脉冲喷动微波真空冷冻干燥;其次,研究不同真空度、不同抽真空时间和不同常压浸渍时间对葛仙米品质的影响,确定最佳的真空含浸工艺为:75℃,-0.08 MPa,真空含浸30 min,再常压浸渍30 min;最后,比较热风干燥与真空微波干燥2种不同的干燥方式对葛仙米品质的影响,确定最佳的二次干燥工艺为:真空微波干燥,150 W。     

葛仙米的研究现状及应用前景

本文综述了葛仙米的营养成分及最新的研究进展,重点分析了葛仙米的营养结构与保健意义,并对葛仙米的开发利用作了展望,还提出了需要解决的问题及主要措施。     

葛仙米多糖的提取、分离与纯化技术研究

葛仙米中富含多糖,并且具有优异的生物和生理活性,本文对葛仙米多糖的提取、分离进行了初步的研究,以期获得性能优良的葛仙米多糖。葛仙米经破碎、脱色、去脂、提取、Sevage法沉淀蛋白质、酒精沉淀多糖、离心、得到粗多糖,最后,通过真空冷冻干燥得到白色的水溶性多糖和褐色的碱溶性多糖,经红外光谱证实：水溶性多糖和碱溶性多糖具有一般多糖的特征。水溶性多糖的最佳提取参数是：90℃,6h,1：90加水,水提取4次,其提取率是14．09％;碱溶性多糖的最佳提取参数是：1mol／L的NaOH溶液,提取6h,加1：25的碱液,提取4次,其提取率是5,70％。     

Enhancement of phototrophic hydrogen production by Rhodobacter sphaeroides ZX-5 using a novel strategy — shaking and extra-light supplementation approach

Biohydrogen has gained attention due to its potential as a sustainable alternative to conventional methods for hydrogen production. In this study, the effect of light intensity as well as cultivation method (standing- and shaking-culture) on the cell growth and hydrogen production of Rhodobacter sphaeroides ZX-5 were investigated in 38-ml anaerobic photobioreactor with RCVBN medium. Thus, a novel shaking and extra-light supplementation (SELS) approach was developed to enhance the phototrophic H₂ production by R. sphaeroides ZX-5 using malate as the sole carbon source. The optimum illumination condition for shaking-culture by strain ZX-5 increased to 7000–8000 lux, markedly higher than that for standing-culture (4000–5000 lux). Under shaking and elevated illumination (7000–8000 lux), the culture was effective in promoting photo-H₂ production, resulting in a 59% and 56% increase of the maximum and average hydrogen production rate, respectively, in comparison with the culture under standing and 4000–5000 lux conditions. The highest hydrogen-producing rate of 165.9 ml H₂/l h was observed under the application of SELS approach. To our knowledge, this record is currently the highest hydrogen production rate of non-immobilized purple non-sulphur (PNS) bacteria. This optimal performance of photo-H₂ production using SELS approach is a favorable choice of sustainable and economically feasible strategy to improve phototrophic H₂ production efficiency.     

Relationship between molecular hydrogen production,proton transport and the F0F1-ATPase activity in Rhodobacter sphaeroides strains from mineral springs

This article aims to study hydrogen production and proton transport in two strains of purple non-sulfur bacterium Rhodobacter sphaeroides isolated from mineral springs of Armenia. This bacterium is able to grow and produce molecular hydrogen (H₂) in anaerobic conditions upon illumination. Along with H₂ production, a marked decrease in redox potential and the alkalization of the medium have been observed; the latter might be the evidence of proton influx. H₂ production and alkalization of the medium by whole cells both are suppressed by the F₀F₁-ATPase inhibitors – N,N′-dicyclohexylcarbodiimide (DCCD), sodium azide (NaN₃) and protonophore – carbonyl cyanide m-chlorophenylhydrazone (CCCP). Membrane vesicles of two strains of R. sphaeroides demonstrate ATPase activity, inhibited by DCCD and NaN₃, but not by CCCP. These results indicate a relationship between H₂ production, proton transport and the F₀F₁-ATPase activity that might be a pathway to regulate bacterial activity under anaerobic conditions.     

葛仙米藻粉对便秘大鼠肠神经递质、ICC及水通道蛋白的影响

研究葛仙米藻粉对便秘大鼠的通便作用机理。实验进行4周,随机将大鼠分为对照组、模型组、葛仙米组。对照组连续灌胃生理盐水4周;葛仙米组大鼠连续灌胃0.8 g/kg的葛仙米4周,同时从第4周起葛仙米组灌胃3 mg/kg的盐酸洛哌丁胺;模型组从第1周到第3周灌胃等量生理盐水,第4周灌胃等量盐酸洛哌丁胺。酶联免疫吸附实验法（enzyme-linked immunosorbent assays,ELISA）测定大鼠结肠组织神经递质含量,免疫组化法测定大鼠结肠水通道蛋白表达以及Cajal间质细胞（interstitial cell of Cajal,ICC）标志物c-kit含量。结果显示：（1）模型组大鼠产生首粒黑便的时间显著高于对照组和葛仙米组（p<0.01）。（2）模型组结肠组织5-羟色胺（5-hydroxytryptamine,5-HT）、P 物质（substance P,SP）含量显著低于对照组和葛仙米组（p<0.05）,血管活性肠肽（vasoacticeintestinalpolypeptide,VIP）含量显著高于对照组和葛仙米组（p<0.05）。（3）模型组结肠水通道蛋白3（aquaporm3,AQP3）水平显著低于对照组和葛仙米组,水通道蛋白4（aquaporm4,AQP4）水平显著高于对照组和葛仙米组（p<0.05）。（4）模型组结肠ICC细胞c-kit表达显著低于对照组和葛仙米组（p<0.01）。上述结果表明,葛仙米藻粉对便秘大鼠的通便作用,其机理可能与肠神经递质5-HT、SP以及VIP分泌、ICC细胞的结构与功能以及水通道蛋白表达有关。