Statistical optimization of culture conditions for bacterial cellulose production using Box-Behnken design

Culture conditions in a jar fermentor for bacterial cellulose (BC) production from A. xylinum BPR2001 were optimized by statistical analysis using Box-Behnken design. Response surface methodology was used to predict the levels of the factors, fructose (X1), corn steep liquor (CSL) (X2), dissolved oxygen (DO) (X3), and agar concentration (X4). Total 27 experimental runs by combination of each factor were carried out in a 10-L jar fermentor, and a three-dimensional response surface was generated to determine the effect of the factors and to find out the optimum concentration of each factor for maximum BC production and BC yield. The fructose and agar concentration highly influenced the BC production and BC yield. However, the optimum conditions according to changes in CSL and DO concentrations were predicted at almost central values of tested ranges. The predicted results showed that BC production was 14.3 g/L under the condition of 4.99% fructose, 2.85% CSL, 28.33% DO, and 0.38% agar concentration. On the other hand, BC yield was predicted in 0.34 g/g under the condition of 3.63% fructose, 2.90% CSL, 31.14% DO, and 0.42% agar concentration. Under optimized culture conditions, improvement of BC production and BC yield were experimentally confirmed, which increased 76% and 57%, respectively, compared to BC production and BC yield before optimizing the culture conditions.     

后河自然保护区珍稀濒危植物种群分布格局的分形特征：计盒维数

通过4种优势树种和7种珍稀树种种群的计盒维数来反映种群分布格局的分形特征．结果表明,4种优势种群的计盒维数在1．346-1．414之间,在历研究的整个常绿落叶阔叶混交林群落中占据了较大的生态空间;其中尖连蕊茶种群的计盒维数最大,占据最大的生态空间．而7种珍稀树种种群的计量续数除了金钱槭种群大于1之外,其余6个种群的计盒维数都小于1,说明它们占据生态空间的能力较小．并且这11个种群的拐点尺度都出现在5-12．5m之间．根据分形的自相似性,可以推断种群在大于拐点尺度的所有尺度上都为同一分布类型,并且在拐点前后种群的格局类型夏发生变化．种群分布格局的判定结果部分地验证了这一观点,11个物种中有5个物种的种群格局在拐点前后发生变化,另6种没有发生这种变化。     

POTENTIAL USE OF LEAF BIOMASS,ARAUCARIA HETEROPHYLLA FOR REMOVAL OF Pb+2

The present investigation attempt to analyze the biosorption behavior of novel biosorbent, Araucaria heterophylla (green plant) biomass, for removal of Pb⁺² from solution as the function of initial metal ion concentration, pH, temperature, sorbent dosage and biomass particle size. The maximum biosorption was found to be 95.12% at pH 5 and biosorption capacity (q_e) of Cd⁺² is 9.643 mg/g. The Langmuir and Freundlich equilibrium adsorption isotherms were studied and observed that Freundlich model is best fit than the Langmuir model with correlation coefficient of 0.9927. Kinetic studies indicated that the biosorption process of Cd⁺² followed well pseudo second order model with R² 0.999. The process is exothermic and, spontaneous. The chemical functional groups –OH, CH₂ stretching vibrations, C?O of alcohol, C?O of amide, P?O stretching vibrations, –CH, were involved in the process. The XRD pattern of the A. heterophylla was found to be mostly amorphous in nature. The SEM studies showed Pb⁺² biosorption on selective grains of the biosorbent. It was concluded that A. heterophylla leaf powder can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Pb⁺² from aqueous solution.     

关于可以表示成自仿射分形的生物体两种维数的计算

分形维数分析已经有效地被用来确定某些生物过程的主要特征。然而某些分形维数的计算还有待用新的数学方法来进一步研究和推广．而且人们普遍认为一些“自然分形”的盒维数和豪斯托夫维数都相等,但仍未用相关的数学理论来证明．本文就是研究象羊齿叶、青草等这样的“自然分形”两种维数的计算问题,得出了两个新结果．     

Biophysical properties and finger print of Boswellia Sp. Burseraceae

For the first time a finger print analysis via high-performance thin layer chromatography (HPTLC) of Boswellia Sp. Burseraceae was accomplished. A preliminary investigation of the Boswellia Sp. Burseraceae displayed the presence of chemical constituents that could be involved in the production of innovative pharmaceuticals for an array of antiviral, anticancer, and antibacterial uses. Moreover, the finger print analysis would deem useful for establishing HPTLC standardization for natural and herbal photochemical constituents.     

Comparison of endogenous phosphorylation of hen and rat spinal cord proteins and partial characterization of optimal phosphorylation conditions for hen spinal cord

The optimal conditions for the endogenous phosphorylation of hen spinal cord cytosolic and membrane proteins with 5 μM [γ-³²P]ATP, 10 mM MgCl₂, were determined by 10% SDS-polyacrylamide gel electrophoresis, autoradiography, and microdensitometry. Phosphate incorporation increased linearly with concentrations ranging from 35–75 μg/100 μl for cytosolic proteins and 21–125 μg/200 μl for membrane proteins. Optimal incubation times, temperatures, and pH values were 60 s, 30°C, and 6.0, respectively, for spinal cord cytosolic proteins and 15 s, 45°C, and 8.0, respectively, for spinal cord membranes. Prominent species differences in protein phosphorylation between these fractions in hens and similarly prepared fractions in rats, co-electrophoresed, include 80K and 30K protein phosphate acceptors unique to rat spinal cord cytosol, 60K and 16K protein phosphate acceptors characteristic of rat spinal cord membranes, a 50K protein phosphate acceptor present only in hen spinal cord membranes, and greater phosphorylation of a more abundant 20K protein in both hen spinal cord fractions. The functional significance of these differences is presently unclear. However, their characterization provides a basis from which to launch future investigations of the biochemistry, pharmacology, and toxicology of spinal cord protein phosphorylation and indicates that caution should be exercised in the choice of an animal model with characteristics appropriate to those of the system it is representing.     

Microtubules and the organization of the Golgi complex

Electron microscopic and cytochemical studies indicate that microtubules play an important role in the organization of the Golgi complex in mammalian cells. During interphase microtubules form a radiating pattern in the cytoplasm, originating from the pericentriolar region (microtubule-organizing centre). The stacks of Golgi cisternae and the associated secretory vesicles and lysosomes are arranged in a circumscribed juxtanuclear area, usually centered around the centrioles, and show a defined orientation in relation to the rough endoplasmic reticulum. Exposure of cells to drugs such as colchicine, vinblastine and nocodazole leads to disassembly of microtubules and disorganization of the Golgi complex, most typically a dispersion of its stacks of cisternae throughout the cytoplasm. These alterations are accompanied by disturbances in the intracellular transport, processing and release of secretory products as well as inhibition of endocytosis. The observations suggest that microtubules are partly responsible for the maintenance and functioning of the Golgi complex, possibly by arranging its stacks of cisternae three-dimensionally within the cell and in relation to other organelles and ensuring a normal flow of material into and away from them. During mitosis, microtubules disassemble (prophase) and a mitotic spindle is built up (metaphase) to take care of the subsequent separation of the chromosomes (anaphase). The breaking up of the microtubular cytoskeleton is followed by vesiculation of the rough endoplasmic reticulum and partial atrophy, as well as dispersion of the stacks of Golgi cisternae. After completion of the nuclear division (telophase), the radiating microtubule pattern is re-established and the rough endoplasmic reticulum and the Golgi complex resume their normal interphase structure. This sequence of events is believed to fulfil the double function to provide tubulin units and space for construction of the mitotic spindle and to guarantee an approximately equal distribution of the rough endoplasmic reticulum and the Golgi complex on the two daughter cells.     

Repair of potentially lethal damage in yeast induced by fast neutrons

Survival curves of 3 diploid (D7) yeast strains: one wild-type, one deficient in excision of pyrimidine dimers (UV-sensitive) and one blocked in DNA double-strand-break repair (X-ray-sensitive), were compared after irradiation with cyclotron-produced fast neutrons. It was observed that both the UV-sensitive (rad3/rad3) and the X-ray-sensitive (rad52/rad52) mutants were more sensitive to neutrons than the wild-type. The role of DNA double-strand-breaks in neutron-induced cell death was further studied by comparing the relative sensitivity of the rad52/rad52 mutant to gamma-rays and fast neutrons. A comparison of the dose modification factors revealed that the deficiency in DNA double-strand-break repair did not make the yeast cells more sensitive to neutrons than to photons, which suggests that lesions of a different type may also be produced by neutrons. Survival curves obtained upon immediate plating and after delayed plating of neutron-irradiated cells showed that all 3 yeast strains were efficient in liquid holding recovery. The role of different repair pathways in cellular recovery from neutron-induced lethal damage is discussed.     

Beclobrinic acid--a new hypolipidemic agent--inhibits in vitro human platelet activation by blocking prostaglandin synthesis

Effects and the mechanism of the antiplatelet actions of beclobrinic acid, free acid form of a new hypolipidemic agent beclobrate [(+)-2-[d-(P-chlorophenyl)p-tolyl)oxy)-2-methyl-butyrate), were examined using human platelets. Platelet-rich plasma (PRP) which has been prelabeled with (14C)-serotonin was incubated with beclobrinic acid (BBA) for one minute before the addition of various agonists. BBA (0.1-1.5 mM) inhibited platelet aggregation and serotonin secretion induced by ADP, epinephrine, arachidonic acid and collagen in a concentration dependent manner. BBA also inhibited arachidonic acid-induced production of malondialdehyde (MDA), a byproduct of prostaglandins, in a concentration dependent manner. However, up to 1.0 mM BBA did not inhibit platelet aggregation induced by U46619, a stable analog of prostaglandin H2. In other experiments BBA also blocked thrombin-induced release of (3H)-arachidonic acid from platelet phospholipids. These findings suggest that: (a) BBA inhibits platelet aggregation and serotonin secretion by inhibiting prostaglandin synthesis at two steps. First by interfering in the release of arachidonic acid from platelet phospholipids and second by inhibiting its conversion into prostaglandins; and (b) BBA does not inhibit the action of prostaglandins on human platelets.