Structure of Porriolide,a New Metabolite from Alternaria porri

Compounds from a soil isolate of Penicillium sp. MG-11 showed remarkable convulsive activity against silkworms. Activity-based fractionation of an acetone extract of the fermentation products resulted in the isolation of four compounds. One was identified as verruculogen, which was an active principle. Another compound, acetoxydehydroaustin, was new and was structurally characterized by spectral data and a single-crystal X-ray analysis. The two other compounds were identified as dehydroaustin and austin on the basis of the spectral data. Although the latter three compounds were not active themselves, they enhanced the convulsive activity of verruculogen in a silkworm bioassay. Three additional compounds with no identifiable activity were also isolated. Two of them were identified as austinol and dehydroaustinol, and the third was determined to be a new related compound named neoaustin by an X-ray analysis of crystals.     

Polyethylene glycol‐based low generation dendrimers functionalized with β‐cyclodextrin as cryo‐ and dehydro‐protectant of catalase formulations

Polyethylene glycol (PEG)‐based low generation dendrimers are analyzed as single excipient or combined with trehalose in relation to their structure and efficiency as enzyme stabilizers during freeze‐thawing, freeze‐drying, and thermal treatment. A novel functional dendrimer (DG_o‐CD) based on the known PEG's ability as cryo‐protector and β‐CD as supramolecular stabilizing agent is presented. During freeze‐thawing, PEG and β‐CD failed to prevent catalase denaturation, while dendrimers, and especially DG_o‐CD, offered the better protection to the enzyme. During freeze‐drying, trehalose was the best protective additive but DG_o‐CD provided also an adequate catalase stability showing a synergistic behavior in comparison to the activities recovered employing PEG or β‐CD as unique additives. Although all the studied dendrimers improved the enzyme remaining activity during thermal treatment of freeze‐dried formulations, the presence of amorphous trehalose was critical to enhance enzyme stability. The crystallinity of the protective matrix, either of PEG derivatives or of trehalose, negatively affected catalase stability in the freeze‐dried systems. When humidified at 52% of relative humidity, the dendrimers delayed trehalose crystallization in the combined matrices, allowing extending the protection at those conditions in which normally trehalose fails. The results show how a relatively simple covalent combination of a polymer such as PEG with β‐CD could significantly affect the properties of the individual components. Also, the results provide further insights about the role played by polymer–enzyme supramolecular interactions (host–guest crosslink, hydrogen bonding, and hydrophobic interactions) on enzyme stability in dehydrated models, being the effect on the stabilization also influenced by the physical state of the matrix. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:786–795, 2013     

核桃壳提取液用于单针藻Monoraphidium sp.QLZ-3培养产油脂

[目的] 研究核桃壳提取液（walnut shell extracts,WSE）对单针藻Monoraphidium sp.QLZ-3生长和油脂积累的影响。[方法] 向BG-11培养基中添加不同量的WSE（培养基中保留有BG-11中全部营养成分）。[结果] 结果显示,当BG-11培养基中的WSE含量为40%时,单针藻的生物量产率及油脂产率达到（534.70±4.07）mg/（L·d）和（296.35±15.36）mg/（L·d）,相比对照组分别提高了的14.82%和33.50%,蛋白质和碳水化合物含量分别有不同程度的上调和下调。与对照组相比,微藻中谷胱甘肽（glutathione,GSH）和超氧化物歧化酶（superoxide dismutase,SOD）含量与活性均上调。此外,WSE作用下,微藻对多酚的移除达到84.37%,同时上调了核酮糖1,5-二磷酸羧化酶基因（ribulose 1,5-bisphosphate carboxylase/oxygenase,rbcL）和乙酰辅酶A羧化酶（acetyl coenzyme A carboxylase,accD）基因的表达量。[结论] 研究表明,WSE联合BG-11可以提高微藻的生物量产率和油脂产率,降低微藻培养的原料成本,为核桃壳的资源化利用及微藻的工业化生产提供了一定的技术支撑。     

Components of the cytosolic and released virtosomes from stimulated and non-stimulated human lymphocytes

Abstract aimThis work intends to analyse the structure and the composition of virtosomes and their role.BackgroundVirtosomes are newly synthesized DNA-RNA-lipoprotein complexes released from living cells in a regulated and energy-dependent manner.MethodsVirtosome fractions were isolated by ultracentrifugation from human lymphocytes cytoplasm and from culture medium before and after stimulation with phitoemoagglutinin (PHA). The composition in DNA, RNA, protein and lipids was determined. The virtosomes present in the culture medium were put in contact with lymphocytes.ResultsVirtosome fractions released from non-stimulated lymphocytes are shown to reduce replication of stimulated lymphocytes and those from stimulated lymphocytes to increase multiplication of non-stimulated lymphocytes. Biochemical analyses of the virtosomal complexes have shown that those from stimulated lymphocytes have five proteins that are absent from non-stimulated virtosome fractions. A comparison of the cytosolic versus released virtosome fractions from non-stimulated lymphocytes indicated that there is a greater percentage of phospholipids in the released virtosomes with a corresponding decrease in the percentage of protein.ConclusionAlthough there is a presence of cholesterol in the virtosomes, the low levels of phosphatidylcholine and cholesterol, together with the low ratios of cholesterol: phospholipids leads to a confirmation of the apparent lack of a limiting membrane around the virtosomes.General significanceVirtosomes are structural particles formed in the cytoplasm, released from the cells and capable to be transferred in other cells influencing their behaviour.     

Serum replacement with albumin‐associated lipids prevents excess aggregation and enhances growth of induced pluripotent stem cells in suspension culture

Suspension culture systems are currently under investigation for the mass production of pluripotent stem (PS) cells for tissue engineering; however, the control of cell aggregation in suspension culture remains challenging. Existing methods to control aggregation such as microwell culture are difficult to scale up. To address this issue, in this study a novel method that incorporates the addition of KnockOut Serum Replacement (KSR) to the PS cell culture medium was described. The method regulated cellular aggregation and significantly improved cell growth (a 2‐ to 10‐fold increase) without any influence on pluripotency. In addition, albumin‐associated lipids as the major working ingredient of KSR responsible for this inhibition of aggregation were identified. This is one of the simplest methods described to date to control aggregation and requires only chemically synthesizable reagents. Thus, this method has the potential to simplify the mass production process of PS cells and thus lower their cost. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1009–1016, 2016     

Chlorella vulgaris as a lipid source: Cultivation on air and seawater‐simulating medium in a helicoidal photobioreactor

The freshwater microalga Chlorella vulgaris was cultured batchwise on the seawater‐simulating Schlösser medium either in a 1.1‐L‐working volume helicoidal photobioreactor (HeP) or Erlenmeyer flask (EF) as control and continuously supplying air as CO₂ source. In these systems, maximum biomass concentration reached 1.65 ± 0.17 g L^?1 and 1.25 ± 0.06 g L^?1, and maximum cell productivity 197.6 ± 20.4 mg L^?1 day^?1 and 160.8 ± 12.2 mg L^?1 day^?1, respectively. Compared to the Bold's Basal medium, commonly employed to cultivate this microorganism on a bench‐scale, the Schlösser medium ensured significant increases in all the growth parameters, namely maximum cell concentration (268% in EF and 126% in HeP), maximum biomass productivity (554% in EF and 72% in HeP), average specific growth rate (67% in EF and 42% in HeP), and maximum specific growth rate (233% in EF and 22% in HeP). The lipid fraction of biomass collected at the end of runs was analyzed in terms of both lipid content and fatty acid profile. It was found that the seawater‐simulating medium, despite of a 56–63% reduction of the overall biomass lipid content compared to the Bold's Basal one, led in HeP to significant increases in both the glycerides‐to‐total lipid ratio and polyunsaturated fatty acid content compared to the other conditions taken as an average. These results as a whole suggest that the HeP configuration could be a successful alternative to the present means to cultivate C. vulgaris as a lipid source. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:279–284, 2016     

Phospholipase Dε enhances Braasca napus growth and seed production in response to nitrogen availability

Phospholipase D (PLD), which hydrolyses phospholipids to produce phosphatidic acid, has been implicated in plant response to macronutrient availability in Arabidopsis. This study investigated the effect of increased PLDε expression on nitrogen utilization in Brassica napus to explore the application of PLDε manipulation to crop improvement. In addition, changes in membrane lipid species in response to nitrogen availability were determined in the oil seed crop. Multiple PLDε over expression (PLDε‐OE) lines displayed enhanced biomass accumulation under nitrogen‐deficient and nitrogen‐replete conditions. PLDε‐OE plants in the field produced more seeds than wild‐type plants but have no impact on seed oil content. Compared with wild‐type plants, PLDε‐OE plants were enhanced in nitrate transporter expression, uptake and reduction, whereas the activity of nitrite reductase was higher under nitrogen‐depleted, but not at nitrogen‐replete conditions. The level of nitrogen altered membrane glycerolipid metabolism, with greater impacts on young than mature leaves. The data indicate increased expression of PLDε has the potential to improve crop plant growth and production under nitrogen‐depleted and nitrogen‐replete conditions.