Fatty acids of lipids from cultured soybean and rape cells

Lipids from cultured cells, leaves and seeds of two varieties each of soybean (Glycine max) and oil seed rape (Brassica napus) were separated into neutral lipids, glycolipids and phospholipids and their fatty acids were analysed. Usually, the fatty acid composition differed between corresponding fractions from cultured cells, leaves and seeds. Differences were least marked in (i) the phospholipids from cultured cells and leaves of soybean and (ii) the neutral lipids from cultured cells and seeds of rape. In the cultured cells, the fatty acid composition of the phospholipids differed from that of the glycolipids and neutral lipids, and fatty acids of chain length greater than C₁₈ comprised a large proportion of the fatty acids of the glycolipids.     

Fractionation and Biological Activity of Aspergillus oryzae Elicitor Promoting Biosynthesis of Shikonin Derivatives

The Aspergillus oryzae elicitor was extracted from mycelia. The concentrated crude preparation of which was treated through DEAE-Cellulose, Sepharose-4B. Bio-Gel p- 4 and 732 columns. Elicitor activity was associated with fraction F Ⅰ b2-H, which had no affinity for DEAE-Cellulose and 732 resin. Its molecular weight was 1200～2200 D and its carbohydrate content was 6.7% of that of the crude. The elicitor activity was 120 times higher than that of crude preparation. There were also fractions F Ⅱ of nucleic acids and F Ⅰ b2-Na of nucleotides, amino acids in crude elicitor preparation. They did not affect shikonin derivative formation at low concentration, but inhibited shikonin derivative formation at high concentration. Fraction FIa of polysaccharid nature in the crude preparation which strongly inhibited shikonin derivative formation was another kind of elicitor of a new metabolite yellow pigment.     

利用微生物混合培养物生产沙棘果渣单细胞蛋白

以沙棘果渣作为唯一碳源进行了单细胞蛋白发酵研究。经过筛选,从４０多株霉菌、酵母菌和细菌中选育出Ｍｙ－９３１霉菌－酵母混合培养物能迅速地将沙棘果渣转变为单细胞蛋白。在最佳条件下,沙棘果渣经发酵后,其发酵产品粗蛋白含量达４４．１％。动物饲喂试验证明此发酵产品安全无毒,能部分替代鱼粉用作蛋白饲料。     

Comparison of fatty acid patterns in plant parts and respective callus cultures of Cucumis melo

Root, hypocotyl, cotyledon, stem and leaf of Cucumis melo var. utilissimus seedlings were used for callus induction. Comparison was made between these parts, between callus tissues originating from all the parts and between each part and its callus, with respect to the fatty acid composition of total lipids. In all the parts there was a greater proportion of unsaturated fatty acids, the predominant fatty acid in root, stem and leaf being linolenic acid whilst in the cotyledon linoleic predominated. In the hypocotyl these two acids were present in equal amounts. In callus cultures the proportion of saturated acids was greater and the predominant fatty acid was palmitic. The major unsaturated fatty acid in callus cultures was linolenic. The analysis showed that callus tissue and its respective plant part had different fatty acid patterns and that all the callus cultures had very similar patterns irrespective of their origin.     

Targeted gene exchange in plant cells mediated by a zinc finger nuclease double cut

Genome modification by homology‐directed repair (HDR) is an attractive tool for the controlled genetic manipulation of plants. Here, we report the HDR‐mediated gene exchange of expression cassettes in tobacco BY‐2 cells using a designed zinc finger nuclease (ZFN). The target contained a 7‐kb fragment flanked by two ZFN cutting sites. That fragment was replaced with a 4‐kb donor cassette, which integrates gene markers for selection (kanamycin resistance) and for scoring targeting (red fluorescent protein, RFP). Candidates resulting from cassette exchange were identified by molecular analysis of calli generated by transformation via direct DNA delivery. The precision of HDR‐mediated donor integration was evaluated by Southern blot analysis, sequencing of the integration locus and analysis of RFP fluorescence by flow cytometry. Screening of 1326 kanamycin‐resistant calli yielded 18 HDR events, 16 of which had a perfect cassette exchange at the insert junction and 13 of which produced functional RFP. Our results demonstrate that ZFN‐based HDR can be used for high frequency, precise, targeted exchange of fragments of sizes that are commercially relevant in plants.     

Physiological heterogeneity in Lactobacillus casei fermentations on residual yoghurt whey

Lactobacillus casei is a well-known lactic acid-producer with substantial industrial interest. Currently, inexpensive lactic acid substrates such as residual yoghurt whey are being increasingly employed as revalorization strategies for such polluting food industry wastes. However, the influence of different bioprocessing conditions on the cellular functionality and physiological status of L. casei at single cell level has barely been evaluated to date. In the present study, monitoring the different physiological states of L. casei through multiparametric flow cytometry during lactic acid production from residual yoghurt whey showed that the majority of L. casei cells remained in healthy, metabolically active state (∼70%) under uncontrolled-pH conditions (pH <3.6), whereas a progressive increase in population heterogeneity was determined (increasing the damaged and dead subpopulations) with higher production (41.5 g/L lactate titer) and sugar consumption rates when a pH-controlled strategy at 6.5 was adopted. A segregated kinetic model was additionally developed to better describe the physiological behaviour of microbial heterogeneity, gaining deeper knowledge on the lactic acid-producing ability of each subpopulation under pH-controlled conditions in the mixed sugar co-fermentation. This study provides further understanding on the role of physiological heterogeneity in lactobacilli populations useful to enhance bioprocess performance and thus achieve efficient lactic acid production.     

Stimulation of Phosphatidylinositol Hydrolysis by Brain-Derived Neurotrophic Factor and Neurotrophin-3 in Rat Cerebral Cortical Neurons Developing in Culture

Phosphatidylinositol (PI) breakdown represents a powerful system participating in the transduction mechanism of some neurotransmitters and growth factors and producing two second messengers, diacylglycerol and inositol trisphosphate. The transformation of PC12 neuroblastoma cells into neuron-like cells induced by nerve growth factor (NGF) is preceded by a rapid stimulation of PI breakdown; however, it was not known whether PI breakdown mediates actions of other members of the neurotrophin family. The present study analyzed the effects of NGF, brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) on PI breakdown in primary cultures of embryonic rat brain cells. Cultures were grown for 7 days; PI was then labeled by incubating cultures with myo-[3H]inositol, which then were exposed acutely to growth factors. BDNF and NT-3, but not NGF, elevated the levels of labeled inositol phosphates within 10-15 min after addition to the cultures in a dose-dependent manner. ED50 values for BDNF and NT-3 were 12.4 and 64.5 ng/ml, respectively. Comparable effects were found in cultures of cortical, striatal, and septal cells. The actions of BDNF and NT-3 probably reflect actions on neurons, because no effects were seen in cultures of nonneuronal cells. In contrast, basic fibroblast growth factor induced a marked stimulation of PI breakdown in cultures of nonneuronal cells. K252b, which selectively blocks neurotrophin actions by inhibiting trk-type receptor proteins, prevented the PI breakdown mediated by BDNF and NT-3. The findings suggest that rapid and specific induction of PI breakdown is involved in the signal transduction of BDNF and NT-3, and they provide evidence that cortical neurons are functionally responsive to BDNF and NT-3 during development.     

Leaf litter quality and decomposition rates of yellow birch and sugar maple seedlings grown in mono-culture and mixed-culture pots at three soil fertility levels

Seedlings of yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh.) were grown for 2 years in mono-culture and mixed-culture and at three fertility levels. Following the second growing season, senescent leaves were analysed for N concentration, acid hydrolysable substances (AHS), and nonhydrolysable remains (NHR). A litter sub-sample was then inoculated with indigenous soil microflora, incubated 14 weeks, and mass loss was measured. Litter-N was significantly higher at medium than at poor fertility, as well as in yellow birch than in sugar maple litter. The species effect on litter-N increased with increasing fertility. At medium fertility, litter-N of sugar maple litter was lower in mixed-culture than in mono-culture. AHS, NHR as well the NHR/N ratio were significantly higher in yellow birch than in sugar maple litter. At medium fertility, the NHR/N ratio of sugar maple litter was significantly lower in mono-culture than in mixed-culture. Mass loss was significantly greater at medium and rich fertility than at poor fertility, and in yellow birch than in sugar maple litter. At poor fertility, mixed-litter decomposed at a rate comparable to yellow birch, whereas at medium and rich fertility, mixed-litter decomposed at a rate comparable to sugar maple. There was a significant positive relationship between litter-N and mass loss. A similar positive relationship between NHR and mass loss was presumed to be a species effect on decomposition. Results support the hypothesis that species × fertility and species × mixture interactions can be important determinants of litter quality and, by implication, of site nutrient cycling.     

Degradation of 3-chlorobenzoate by benzoate or 3-methylbenzoate-utilising cultures

Abstract 3-Chlorobenzoate (3CB) was incompletely degraded by bacterial cultures growing continuously with benzoate (Ben) or 3-methylbenzoate (3MB). Accumulation of chlorocatechols as dead-end metabolites was avoided if, prior to the exposure to 3CB, the population had been supplemented with Pseudomonas sp. strain B13 as a chlorocatechol-assimilating member. After acclimatisation, the substrate mixture Ben/3CB was completely degraded via 2 compatible ortho -cleavage pathways.
In contrast, 3MB and 3CB were found to be incompatible substrates: as a result of suicide and genetic inactivation of catechol 2,3-dioxygenase, methylcatechols are subject to unproductive ortho -cleavage. In a defined mixed culture ( Pseudomonas putida mt-2 plus strain B13), 4-carboxymethyl-2-methylbut-2-en-4-olide and 4-carboxymethyl-4-methylbut-2-en-4-olide were excreted as dead-end products, whereas in an undefined mixed culture, degraders of these metabolites became stable members of the community.
Characteristically, with increasing 3CB load, the relative number of 3CB-degrading organisms increased which were Ben⁺ or 3MB⁺ and which had acquired from Pseudomonas sp. strain B13 the ability to assimilate chlorocatechols.