京郊典型集约化"农田-畜牧"生产系统氮素流动特征

城郊畜牧业的集约化发展在满足人们日益增长的肉蛋奶等动物性产品需求的同时,也带来了巨大的环境压力。本文利用养分流动和模型分析的方法,分析北京市郊区某村三种不同类型"农田-畜牧"生产系统(大型集约化种猪场、种养结合小规模生态养殖园和集约化单一种植区)的氮素流动特征。结果表明:饲料是集约化种猪场和生态养殖园氮素输入的主要来源,饲料投入氮量分别为12469.0和9268.5 kg.hm-.2a-1);集约化种猪场农牧体系间生产脱节,致使农田氮素输入主要依赖于化肥投入,化肥氮输入量(435.0 kg.hm-.2a-1)占农田氮素输入量的82.7%。相反,生态养殖园农牧体系结合紧密,猪粪尿氮还田比例达28.6%,这使得园区化肥氮输入量仅为135.0 kg.hm-.2a-1,因此畜禽粪尿的合理循环利用可作为减少化肥投入的有效途径;集约化种猪场、生态养殖园和单一种植区农牧生产系统氮素利用效率分别为18.8%、20.6%和17.3%,均处于较低水平;集约化种猪场猪粪尿在猪舍和储藏处理过程的氮素损失率为15.8%和25.4%,分别低于小规模生态养殖园相应损失率约8.7和4.8个百分点;生态养殖园粪肥氮还田量高,导致农田氮素盈余量高达1962.8 kg.hm-.2a-1,未能实现生态型养殖的理想效果,优化氮素管理、确定合理的消纳畜禽粪尿的农田面积和调整畜禽养殖密度是解决该问题的关键。     

Genetic evidence of "American" and "European" type symbiotic algae of Paramecium bursaria Ehrenberg

Paramecium bursaria is composed of a "host" ciliate and a "symbiont" green alga. Based upon physiology, DNA hybridization and virus infection, two types of symbionts, called "American" type and "European" type, have been reported to date. Here, we determined the 18S rDNA and internal transcribed spacer 2 (ITS2) regions for both "American" and "European" types. Sequence features clearly separated into two lineages; NC64A (USA), Syngen 2-3 (USA), Cs2 (Chinese), MRBG1 (Australian), and Japanese strains belong to the "American", whereas PB-SW1 (German) and CCAP 1660/11 (British) strains belong to the "European". In "American" 18S rDNA, three introns were inserted in the same positions as for previously described Japanese symbionts. In "European" 18S rDNA, a single intron occurred in a different position than in the "American". Between the types, sequence differences were seven or eight nucleotides (0.39 %) in the 18S rDNA exon, and more than 48 nucleotides (19.2 %) in ITS2 regions. We subsequently sequenced the host 18S rDNA. As a result, two groups: Cs2, MRBG1, and Japanese strains, and PB-SW1 and CCAP 1660/11 strains, were separated (with 23 substitutions and 4 insertions or deletions between the groups). The congruent separations between hosts and symbionts may imply that the type of symbiont depends on the host type.     

N-glycan structures of a recombinant mouse soluble Fcγ receptor II

N-glycans of a recombinant mouse soluble Fc receptor II (sFcRII) expressed in baby hamster kidney cells were released from glycopeptides by digestion with glycoamidase A (from sweet almond), and the reducing ends of the oligosaccharides were reductively aminated with 2-aminopyridine. The derivatized N-glycans were separated and structurally identified by a three-dimensional high-performance liquid chromatography (HPLC) mapping technique on three kinds of HPLC columns [Takahashi, et al. (1995) Anal. Biochem. 226: 139–46]. Eighteen different major N-glycan structures were identified, of which six were neutral (45%), five mono-sialyl (49%), one di-sialyl (4.6%), five tri-sialyl (1.1%), and one tetra-sialyl (0.3%). All N-glycan structures determined were complex type with fucosylation at the N-acetylglucosamine residue of the reducing end, and N-acetylneuraminic acid, when present, was -(2,3)-linked. The existence of a unique structure containing both N-acetylgalactosamine and -(2,3)-N-acetylneuraminic acid residues at the reducing ends, as below, was confirmed by MALDI-TOF mass spectrometry.     

Characterization of a proteinaceous extracellular coat synthesized by the “slime” variant of Neurospora crassa

Cells of the slime strain of Neurospora crassa synthesize a coherent extracellular material which remains attached to the cell surface, but is released into the liquid medium by shaking. The material was purified and studied by different criteria. By electron microscopy it appears as long wavy sheets which strongly bind concanavalin A, but not wheat germ agglutinin, and maintain their integrity in the absence of structural polysaccharides. Analysis of the purified material revealed that it was free of contaminating membranes; it contained more than 70% protein, 1% neutral sugars (glucose, mannose, fucose and galactose), less than 2% lipids and ca. 4% not-characterized hexosaminelike compounds. Its polypeptide pattern as determined by PAGE was complex. The significance of this material is discussed.Abbreviations used Au-WGA colloidal gold-wheat germ agglutinin - Endo H endo--N-acetylglucosaminidase H - Fe-Con A ferritin labcled concanavalin A - FITC-Con A fluorescent concanavalin A - PEM proteinaceous extracellular material - PMSF phenylmethyl sulfphonyl fluoride - BSDA bovine serum albumin - CTAB cetyltrimethyl-ammonium bromide - DOC-Na sodium deoxychlate - DTT dl-dithiothreitol - EDTA ethylene diamine tetracetic acid     

Isolation and characterization of an ω3-desaturation-defective mutant of an arachidonic acid-producing fungus,Mortierella alpina 1S-4

A mutant considered to be defective in the conversion of n-6 to n-3 fatty acids (3-desaturation) was derived from a 5-desaturation-defective mutant (Mut44) of Mortierella alpina 1S-4, after treating its spores with N-methyl-N-nitro-N-nitrosoguanidine. This mutant cannot produce 8(Z),11(Z),14(Z),17(Z)-eicosatetraenoic acid or any other n-3 fatty acids, of which about 10% was found in its parental strain upon cultivation at 12°C. The mutant's growth rate was comparable to that of the parental strain when grown at 28°C, but it became much slower when the mutant grew at 12°C, at which the lag phase for Mut44 was about 2 d but 5 d for the mutant.Abbreviations 18:33 9(Z),12(Z),15(Z)-octadecatrienoic acid - 18:43 6(Z),9(Z),12(Z),15(Z)-octadecatetraenoic acid - 20:43 8(Z),11(Z),14(Z),17(Z)-eicosatetraenoic acid - AA arachidonic acid - DHGA dihomo--linolenic acid - EPA 5(Z),8(Z),11(Z),14(Z),17(Z)-eicosapentaenoic acid - GLC gas-liquid chromatography - MNNG N-methyl-N-nitro-N-nitrosoguanidine - PC phosphatidylcholine     

Fatty acid composition of vitellogenin from four teleost species

The fatty acid compositions of vitellogenin and liver from cod (Gadus morhua), rainbow trout (Oncorhynchus mykiss), turbot (Scophthalmus maximus) and wolffish (Anarhichas lupus) were determined. Vitellogenin was isolated from plasma of estradiol-17-treated fish by precipitation with EDTA-Mg²⁺ and distilled water or by high-performance ion-exchange chromatography. In all investigated species, vitellogenin contained 16–18% (w/w) lipid, in which polyunsaturated fatty acids, predominantly 20:5 (n-3) and 22:6 (n-3), comprised about 50% of the total fatty acids. The proportions of saturated, monounsaturated, polyunsaturated and (n-3) fatty acids in vitellogenin of the different species were generally similar, although the relative content of specific fatty acids was distinctive for each species. The distribution of fatty acids in total lipids of vitellogenin was highly consistent among individual females of each species. In contrast, liver fatty acid composition varied considerably, both within and between species. Altogether, the differences in the fatty acid composition of vitellogenin and liver from each species indicate that a specific selection of fatty acids occurs during the lipidation of vitellogenin.Abbreviations BHT butylated hydroxytoluene - E-17 estradiol-17 - EDTA ethylenedinitrilo tetra-acetic acid disodium salt dihydrate - FA fatty acids - FAME fatty acid methyl esters - HDL high density lipoproteins - PUFA polyunsaturated fatty acids - SD standard deviation - TLC thin-layer chromatography - VHDL very high density lipoproteins - VLDL very low density lipoproteins - v/v volume per volume - w/v weight per volume - w/w weight per weight     

Possible amelioration of coastal soil salinity using halotolerant nitrogen-fixing cyanobacteria

A brackish-water, nitrogen-fixing cyanobacterium, Anabaena torulosa, could successfully grow and fix nitrogen on moderately saline Kharland soils (soil conductivity 5 to 8.50 dS m-1), typical of Indian coastline. During five weeks of growth under laboratory as well as field conditions, the cyanobacterium exhibited high rates of nitrogen fixation and substantially enriched the nitrogen status of saline soils (43-76%), although the fixed nitrogen remained confined to the cyanobacterial biomass. Most (>90%) of the cell-bound Na+ remained extracellularly trapped in the mucopolysaccharide sheath of A. torulosa; traces of the cation that permeated cyanobacterial cells were found to exist in an osmotically active, free state. No evidence was found for the incorporation of Na+ into any biomolecule, especialty proteins or carbohydrates. Therefore, permanent removal of Na+ from saline soils using cyanobacteria may not be possible, since Na+ is released back into the soil subsequent to the death and decay of cyanobacteria. Removal of top soil containing cyanobacterial mats significantly decreased the soil salinity (between 26-38%). But such a practice removes all the fixed nitrogen and carbon and also does not seem feasible on a large scale. Amelioration of soil salinity by simultaneous application of A. torulosa during crop growth seems to be an attractive possibility, especially since it can also supplement the nitrogen requirement of the crop.     

In vitro shoot regeneration from leaf discs of Betula pendula ‘Dalecarlica’ EM 85

The effect of zeatin, NAA (-naphthaleneacetic acid), putrescine and cefotaxime on the frequency of shoot regeneration from Betula pendula Dalecarlica EM 85 leaf discs has been examined. About 80% of leaf discs were induced to form adventitious shoots when the culture medium contained 45.6 moll^-1 zeatin and 0.1 mmoll^-1 cefotaxime. The addition of NAA to zeatin-containing media prevented shoot regeneration but stimulated root development directly from leaf tissues. Putrescine (0.1 mmoll^-1) and cefotaxime (0.1 mmoll^-1) could both significantly increase the percentage of leaf discs regenerating on optimal zeatin-containing media, and increase the number of shoots per regenerating disc.Abbreviations NAA -naphthaleneacetic acid - BAP 6-benzyladenine     

Chemical induction of interleukin-8, a proinflammatory chemokine,in human epidermal keratinocyte cultures and its relation to cytogenetic toxicity

Tumor promoters, proinflammatory cytokines, endotoxins, and protein synthesis inhibitors can modulate cell cycle kinetics of various cell types, stimulate production of reactive oxygen species, and induce keratinocytes to produce interleukin-8 (IL-8), a potent chemotactant for polymorphonuclear neutrophils and T lymphocytes. The aim of this study was to determine whether perturbations of cytogenetic responses correlated with the induction of IL-8 expression. Cultures of primary human keratinocytes were grown in serum-free medium with 5 mol/L bromodeoxyuridine to label DNA and exposed either to phorbol-13-myristate-12-acetate (PMA) (0.0001–100 ng/ml), cycloheximice (CHX) (0.01–50 g), lipopolysaccharide (0.1–100 g/ml), tumor necrosis factor- (TNF) (3.13–50 ng/ml), or interleukin-1 (IL-1) (1–182 pg/ml). Metaphase chromosome preparations were stained by a fluorescence-plus-Giemsa technique to differentiate sister chromatids. For IL-8 production, keratinocytes were grown to 70% confluency and then exposed to chemicals for 24 h. Immunoreactive IL-8 was quantitated from the supernatants by ELISA. With the exception of benzo(a)pyrene used as a positive control, none of the agents induced sister chromatid exchanges. However, PMA and TNF induced IL-8 production that coincided with significant cell cycle inhibition. IL-1 had no effect on cytogenetic endpoints, yet stimulated a 6.3-fold increase in IL-8. CHX inhibited cell cycle progression and mitotic activity at concentrations that were 200 times lower than required for IL-8 induction; however, puromycin (0.31–10 g/ml), another protein synthesis inhibitor, did not induce IL-8. At all concentrations tested, TNF reduced the mitotic index by 45%, slowed cell cycle progression by 3.5 h, and induced a flat, albeit large, IL-8 response at concentrations 12.5 ng/ml. These agent-specific response patterns suggest that induction of IL-8 production is not always the inevitable result of cell cycle perturbations or genetic damage.Abbreviations B(a)P benzo(a)pyrene - BrdU 5-bromo-2-deoxyuridine - CHX cycloheximide - ICAM intercellular adhesion molecules - IL-1 interleukin-1 - IL-8 interleukin-8 - KGM keratinocyte growth medium - LPS lipopolysaccharide - PKC protein kinase C - PMA phorbol-13-myristate-12-acetate - PMN polymorphonuclear neutrophil - ROS reactive oxygen species - SCE sister chromatid exchange - TNF tumor necrosis factor      

Factors altering DNA synthesis in the cardiac myocyte of the adult newt,Notophthalmus viridescens

To better understand the mechanisms governing the proliferation of cardiac myocytes it is important to identify the factors controlling this phenomenon, and to characterize their actions. DNA synthesis was quantified in vitro in ventricular myocytes from the adult redspotted newt, Notophthalmus viridescens. Ventricles were enzymatically separated and plated onto laminin. Myocytes were fed modified L-15 medium with 10% fetal bovine serum, and were variously treated with transforming growth factor-beta, transforming growth factor-beta combined with platelet-derived growth factor, acidic fibroblast growth factor, basic fibroblast growth factor, 12-0-tetradecanoylphorbol-13-acetate, heparin, or conditioned medium from ventricular myocytes or non-myocytes (primarily endothelial cells). With their final feeding the cells were given 1 Ci/ml of tritiated thymidine, and 24 hours later were fixed and stained. Dishes were coated with photographic emulsion, exposed, and developed. The percent of cells with labeled nuclei was determined. Experimental media that significantly increased DNA synthesis included those containing acidic fibroblast growth factor (121% of control), basic fibroblast growth factor (119% of control), 12-0-tetradecanoylphorbol-13-acetate (233% of control) and conditioned medium from ventricular myocytes (230% of control) or non-myocytes (128% of control). Media significantly inhibiting DNA synthesis were those containing heparin (31% of control), transforming growth factor-beta (38% of control), non-myocyte conditioned medium and heparin (75% of control), or transforming growth factor-beta and platelet-derived growth factor (63% of control).     

Microbial degradation of dehydrodiconiferyl alcohol,a lignin substructure model

Bacteria, yeasts, and molds which grew in a medium containing a synthetic lignin — a dehydrogenation polymer (DHP) of coniferyl alcohol — as a sole carbon source, were isolated from soil. One fungus, Fusarium solani M-13-1, was found to degrade the DHP most vigorously among the isolated organisms. It was shake-cultured in a medium containing dehydrodiconiferyl alcohol (DHCA) (I), an important lignin model compound, and the following six metabolic products were isolated and identified: 1) Phenylcoumaran--aldehydic (II) and -carboxylic compounds, 2) phenylcoumaran--aldehydic compound (IV), formed by release of a 2-carbon fragment from the phenylcoumaran--carboxylic compound, 3) 5-acetylvanillyl alcohol (V), formed by cleavage of the coumaran ring and reduction of the -aldehyde group, 4) 5-carboxyvanillyl alcohol (VI), formed by subsequent oxidation of the acetyl group, and 5) the -ether of DHCA (VII), considered to be a by-product. A degradation pathway for DHCA was proposed on the basis of these metabolic products.Non-Standard Abbreviations DHP dehydrogenation polymer - DHCA dehydrodiconiferyl alcohol - DDQ dichlorodicyano-p-benzoquinone - DDHQ dichlorodicyano-p-hydroquinone - Ar aromatic - TLC thin layer chromatography - GC-MS gas chromatography-mass spectrometry     

Recombinant interferon α-2a in combination with dacarbazine in the treatment of metastatic malignant melanoma: analysis of long-term responding patients

Thirty-four evaluable patients with metastatic malignant melanoma were entered into a phase-II study designed to assess the response rate and analyze the long-term therapeutic efficacy of recombinant interferon (rIFN) -2a and dacarbazine. Patients received 14 days of daily subcutaneous r-IFN-2a (3×10⁶ IU/day), followed by 9×10⁶ IU on alternate days, as long as objective response lasted, in combination with i.v. dacarbazine started on day 7 (400 mg/m²) and repeated every 21 days (dacarbazine doses were escalated to 800 mg/m²). In 11 patients, 6 complete (17.6%) and 5 partial (14.7%) responses were seen, with an overall response rate of 32.3% (95% confidence interval: 16%–48%). The median survival time of the responding patients was significantly better than that of patients with progressive disease (P=0.01) and the median response time of the patients showing complete response was longer than that of the partially responding patients (14 and 7 months respectively,P=0.06).     

Characterization of specific calcitonin gene related peptide receptors present in hamster pancreatic β cells

Calcitonin gene-related peptide (CGRP) shares about 46% and 20% amino acid sequence homology with islet amyloid polypeptide (IAPP) and salmon calcitonin (sCT). We investigated whether these related peptides could cross-react with the specific binding of¹²⁵I-[His]hCGRP I to the CGRP receptor in hamster insulinoma cell membranes. A rapid dissociation of membrane bound¹²⁵I-[His]hCGRP I could be induced in the presence of 1 M chicken CGRP (cCGRP). The specific¹²⁵I-[His]hCGRP I binding was inhibited by the related peptides and their half-maximal inhibitory concentrations (IC₅₀) were: cCGRP (0.1 nM), rat CGRP I and human CGRP I and II (1.0–2.0 nM), fragment of hCGRP I (8-37) (150 nM), human IAPP (440 nM). The non-amidated form of hIAPP; human diabetes-associated peptide (hDAP) did not inhibit the binding of¹²⁵I-[His]hCGRP I and sCT was only effective at a high concentration (1 M). Binding of¹²⁵I-[His]hCGRP I was dose dependently inhibited by guanosine-5-O-(3-thiotriphosphate) or (GTPS) and a 70% reduction of binding was obtained with 0.1 mM GTPS. The IC₅₀ value of cCGRP (0.1 nM) was increased 100-fold in the presence of 0.1 mM GTPS. Human CGRP I and cCGRP at 2.5 M did not stimulate the activity of hamster insulinoma cell membranes adenylate cyclase, while glucagon (1 M) induced a 2-fold increase. Thus, specific CGRP receptors present in hamster cells are associated with G protein (s) and IAPP can interact with these receptors. These results and the observation that cCGRP and hCGRP I did not influence adenylate cyclase activity provide further evidence for CGRP receptor subtypes.Abbreviations CGRP calcitonin gene-related peptide - IAPP islet amyloid polypeptide - IC₅₀ half-maximal inhibitory concentration - GTPS guanosine-5-O-(3-thiotriphosphate) - ¹²⁵I [His]hCGRP I, (2[¹²⁵I]iodohistidyl¹⁰) human CGRP I     

Effects of β-Amyloid-(25-35) Peptides on Radioligand Binding to Excitatory Amino Acid Receptors and Voltage-Dependent Calcium Channels: Evidence for a Selective Affinity for the Glutamate and Glycine Recognition Sites of the NMDA Receptor

The neurotoxic fragment corresponding to residues 25-35 of the -amyloid (A) peptide [A-(25-35)] has been shown to exert effects on (+)-[³H]5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10-imine maleate ([³H]MK-801) binding to the cation channel of the N-methyl-D-aspartate (NMDA) receptor. In the present study, we investigated whether the amidated and carboxylic acid C-terminated forms of A-(25-35) [A-(25-35-NH₂) and A-(25-35-COOH), respectively] exert effects on other excitatory amino acid receptor and cation channel types in rat cortical membranes. Both A-(25-35-NH₂) and A-(25-35-COOH) gave statistically significant dose-dependent inhibitions of [³H]glutamate and [³H]glycine binding to the agonist recognition sites of the NMDA receptor. Ten M A-(25-35-NH₂) and A-(25-35-COOH) gave 25% and 20% inhibitions of [³H]glutamate binding and 75% and 70% inhibitions of [³H]glycine binding, respectively. A-(25-35-NH₂), but not A-(25-35-COOH), gave a small (ca. 17% at 10 M) statistically significant increase of [³H]amino-3-hydroxy-5-methylisoxazole-4-propionate ([³H]AMPA) binding. [³H]kainate binding was not significantly affected by either peptide. Similarly, neither peptide affected either the maximal level or EC₅₀ value for calcium stimulation of [³H]nitrendipine binding. It is concluded that A-(25-35) shows slight affinity for the agonist recognition sites of the NMDA receptor, but not for other excitatory amino acid receptor types or for L-type voltage-dependent calcium channels.     

Rat hepatocytes prepared without collagenase: Prolonged retention of differentiated characteristics in culture

Rat hepatocytes prepared by collagenase digestion or ED TA dissociation were examined in culture for comparison of culture stability and morphology, and retention of selected adult rat liver characteristics. Cells prepared by EDTA perfusion followed by Percoll cen trifugation were deemed to form confluent monolayer cultures more rapidly and monolayers remained intact for up to 21 days without signs of nonparenchymal cell growth or loss of primary hepatocyte appearance. The spectrally determined cytochrome P-450 content remained constant through eight days in culture. Collagenase prepared cells contained an identical amount of P-450 but within 72 hr lost greater than 80% of the spectrally detectable P-450. Glutathione (GSH) content was higher in the EDTA-prepared hepatocytes and remained constant with only a modest effect of transferrin and selenium (TI S) supplementation, while GSH levels in collagenaseprepared cells increased, thereafter decreased with time in culture and was dependent on TI S supplementation. Cells prepared with ED TA also displayed an increase in GSH efflux rate in response to chronic GSH depletion by ethacrynic acid. -Cystathionase (CNase) activity was retained at initial levels in ED TAprepared hepatocytes supplemented with TI S and declined only about 25% in unsupplemented cells. Collagenase-prepared cells lost 75% of CNase activity by 72 hr. The established marker of hepatocyte neoplastic transformation, -glutamyl trans-peptidase (GGT), increased rapidly in collagenase-prepared cells. The accumulation of GGT was slowed by T/S supplementation. GGT activity did not increase in EDTA-prepared hepatocytes. Evaluation of morphological and biochemical criteria suggest that hepatocytes prepared without collagenase present superior model systems for the study of biochemical events through more extended culture times.Abbreviations CNase -cystathionase - EDTA ethylenediamine tetraacetic acid - GGT -glutamyl transpeptidase - GSH reduced glutathione - GSSG oxidized glutathione - HEPES N-2-hydroxyethylpiperizine-N-2-ethane-sulfonic acid - SAH S-adenosylhomocysteine - SAM S-adenosylmethionine - T/S transferrin- and selenite-supplemented     

Evolution of PS IIα and PS IIβ centers during the greening of Euglena gracilis Z: Correlations with changes in lipid content

The building up of the two types of reaction centers, PS II and PS II, was investigated during the greening of Euglena gracilis Z cells in resting medium. The maximal values in the proportion of PS II centers (55%) and in the oxygen evolved per chlorophyll were reached at the outbreak of greening, when accumulation of galactolipids (MGDG and DGDG) rich in unsaturated fatty acids occurred, and when anionic lipids (SQDG and PG) emerged. As the greening progressed, the chlorophyll accumulation corresponded to a secondary enrichment in PS II centers, which built up more rapidly than PS II centers; correlatively, a general saturation of the fatty acids constitutive of all lipid classes took place.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - DGDG digalactosyldiacylglycerol - FAME Tatty acid methyl esters - HEPES acide (N-[2-hydroxyethyl]piperazine-N-[2-ethane sulfonic] - MGDG monogalactosyldiacylglycerol - PC phosphatidylcholine - PE phosphatidylethanolamine - PG phosphatidylglycerol - PQ plastoquinone - PS I Photosystem I - PS II Photosystem II - Q_A primary quinone electron acceptor of PS II - Q_B secondary quinone electron acceptor of PS II - SQDG sulfoquinovosyldiacylglycerol     

Models for glycosidic juvenogens: Enzymic formation of selected alkyl-β-D-glucopyranosides and alkyl-β-D-galactopyranosides under microwave irradiation

2-(4-Methoxybenzyl)-1-cyclohexyl--d-glucopyra nosides (1b and 2b) and 2-(4-methoxybenzyl)-1-cyclohexyl--d-galactopy ranosides (1c and 2c), models for glycosidic juvenogens, were synthesized using either D-glucose or D-galactose [in their natural form (3 and 5) or activated form (4 and 6)], and the respective racemic cis or trans isomers of 2-(4-methoxybenzyl)-1-cyclohexanol (1a and 2a) by either enzymic reverse hydrolysis or transglycosylation under both standard heating and microwave irradiation. Commercially available almond -glucosidase (EC 3.2.1.21) or -galactosidase (EC 3.2.1.23) from Escherichia coli were employed using different acetonitrile/water mixtures [9/1 (v/v) for the reverse hydrolysis, and 4/1 (v/v) for the transglycosylation].     

Inhibition of anthocyanin formation in seedlings and flowers by the enantiomers of α-aminooxy-β-phenylpropionic acid and their N-benzyloxycarbonyl derivatives

Both enantiomers of -aminooxy--phenylpropionic acid (AOPP), potent inhibitors of L-phenylalanine ammonia-lyase, and their N-benzyloxycarbonyl (N-BOC) derivatives inhibit anthocyanin formation in developing flowers of Ipomoea tricolor Cav. and Catharanthus roseus Don. as well as in seedlings of Brassica oleracea var. caulo-rapa DC (kohlrabi) and B. oleracea var. capitata L. (red cabbage) with little interference with their normal development. Kohlrabi seedlings tolerate up to 0.3 mM L-AOPP and N-BOC-L-AOPP without a reduction of fresh weight or chlorophyll content, while anthocyanin is reduced to less than 20%.Abbreviations AOPP -aminooxy--phenylpropionic acid - N-BOC N-benzyloxycarbonyl - PAL L-phenylalanine ammonia-lyase (EC 4.3.1.5)