Antagonistic Activity of Oroxylin A against Fusarium graminearum and Its Inhibitory Effect on Zearalenone Production.

Fusarium graminearum produces zearalenone (ZEA), a mycotoxin that is widely found in food and feed products and is toxic to humans and livestock. Piper sarmentosum extract (PSE) inhibits F. graminearum, and Oroxylin A appears to be a major antifungal compound in PSE. The aim of this study is to quantify the Oroxylin A content in PSE using UPLC-QTOF-MS/MS, and to investigate the antagonistic activity of Oroxylin A against F. graminearum and its inhibitory effect on ZEA production. The results indicate that Oroxylin A inhibits both fungal growth and ZEA production in a dose-dependent manner. Oroxylin A treatment downregulated the mRNA expression of zearalenone biosynthesis protein 1 (ZEB1) and zearalenone biosynthesis protein 2 (ZEB2). The metabolomics analysis of F. graminearum mycelia indicated that the level of ribose 5-phosphate (R5P) deceased (p < 0.05) after Oroxylin A treatment (64-128 ng/mL). Moreover, as the Oroxylin A treatment content increased from 64 to 128 ng/mL, the levels of cis-aconitate (p < 0.05) and fumarate (p < 0.01) were upregulated successively. A correlation analysis further showed that the decreased R5P level was positively correlated with ZEB1 and ZEB2 expression, while the increased cis-aconitate and fumarate levels were negatively correlated with ZEB1 and ZEB2 expression. These findings demonstrate the potential of Oroxylin A as a natural agent to control toxigenic fungi and their mycotoxin.

Singlet oxygen-induced signalling depends on the metabolic status of the Chlamydomonas reinhardtii cell.

Using a mutant screen, we identified trehalose 6-phosphate phosphatase 1 (TSPP1) as a functional enzyme dephosphorylating trehalose 6-phosphate (Tre6P) to trehalose in Chlamydomonas reinhardtii. The tspp1 knock-out results in reprogramming of the cell metabolism via altered transcriptome. As a secondary effect, tspp1 also shows impairment in 1O2-induced chloroplast retrograde signalling. From transcriptomic analysis and metabolite profiling, we conclude that accumulation or deficiency of certain metabolites directly affect 1O2-signalling. 1O2-inducible GLUTATHIONE PEROXIDASE 5 (GPX5) gene expression is suppressed by increased content of fumarate and 2-oxoglutarate, intermediates in the tricarboxylic acid cycle (TCA cycle) in mitochondria and dicarboxylate metabolism in the cytosol, but also myo-inositol, involved in inositol phosphate metabolism and phosphatidylinositol signalling system. Application of another TCA cycle intermediate, aconitate, recovers 1O2-signalling and GPX5 expression in otherwise aconitate-deficient tspp1. Genes encoding known essential components of chloroplast-to-nucleus 1O2-signalling, PSBP2, MBS, and SAK1, show decreased transcript levels in tspp1, which also can be rescued by exogenous application of aconitate. We demonstrate that chloroplast retrograde signalling involving 1O2 depends on mitochondrial and cytosolic processes and that the metabolic status of the cell determines the response to 1O2.

Insecticidal potential of extracts, fractions, and molecules of Aconitum heterophyllum Wall ex. Royle against aphid Aphis craccivora Koch (Hemiptera: Aphididae).

BACKGROUND: Aphis craccivora is the major sap-sucking pest of leguminous crops and vector of plant viruses that cause damage to plants and reduce yield. Indiscriminate and nonjudicious use of synthetic insecticides led to resistance development and harmful to environment. Therefore, it is important to discover plant-based lead(s) which can replace synthetic insecticides. In the current study the residual toxicity of extracts, fractions, and isolated compounds of Aconitum heterophyllum were evaluated against A. craccivora to identify lead(s) for further development of botanical formulation. RESULTS: In residual contact assay, ethanolic (LC50  = 2837.17 mg L-1 ) and aqueous methanolic extracts (LC50  = 2971.59 mg L-1 ) were effective against A. craccivora. Among fractions, the n-butanol fraction of the aqueous methanolic extract (LC50  = 986.96 mg L-1 ) was found to be most effective, followed by the ethyl acetate fraction of the ethanolic extract (LC50  = 1037.52 mg L-1 ) and the n-hexane fraction of both extracts (LC50  = 1113.85 to 1233.11 mg L-1 ). Among pure molecules, aconitic acid was found to be the most effective (68% mortality; LC50  = 1313.19 mg L-1 ) and was on a par with azadirachtin 0.15% EC (66% mortality; LC50  = 1921.10 mg L-1 ). Furthermore, from the effect of ethanoic extract on detoxification enzyme inhibition in A. craccivora we concluded that the target site of action of this extract in A. craccivora might be glutathione S-transferase. CONCLUSIONS: The parent extract/fractions of A. heterophylum showed promising activity against A. craccivora. Among phytoconstituents of the active extract and fractions, aconitic acid was found to be on a par with azadirachtin 0.15% EC. © 2022 Society of Chemical Industry.

Flavonifractor plautii Protects Against Elevated Arterial Stiffness.

BACKGROUND: Dysbiosis of gut microbiota plays a pivotal role in vascular dysfunction and microbial diversity was reported to be inversely correlated with arterial stiffness. However, the causal role of gut microbiota in the progression of arterial stiffness and the specific species along with the molecular mechanisms underlying this change remain largely unknown. METHODS: Participants with elevated arterial stiffness and normal controls free of medication were matched for age and sex. The microbial composition and metabolic capacities between the 2 groups were compared with the integration of metagenomics and metabolomics. Subsequently, Ang II (angiotensin II)-induced and humanized mouse model were employed to evaluate the protective effect of Flavonifractor plautii (F plautii) and its main effector cis-aconitic acid. RESULTS: Human fecal metagenomic sequencing revealed a significantly high abundance and centrality of F plautii in normal controls, which was absent in the microbial community of subjects with elevated arterial stiffness. Moreover, blood pressure only mediated part of the effect of F plautii on lower arterial stiffness. The microbiome of normal controls exhibited an enhanced capacity for glycolysis and polysaccharide degradation, whereas, those of subjects with increased arterial stiffness were characterized by increased biosynthesis of fatty acids and aromatic amino acids. Integrative analysis with metabolomics profiling further suggested that increased cis-aconitic acid served as the main effector for the protective effect of F plautii against arterial stiffness. Replenishment with F plautii and cis-aconitic acid improved elastic fiber network and reversed increased pulse wave velocity through the suppression of MMP-2 (matrix metalloproteinase-2) and inhibition of MCP-1 (monocyte chemoattractant protein-1) and NF-κB (nuclear factor kappa-B) activation in both Ang II-induced and humanized model of arterial stiffness. CONCLUSIONS: Our translational study identifies a novel link between F plautii and arterial function and raises the possibility of sustaining vascular health by targeting gut microbiota.

cis-Aconitic Acid, a Constituent of Echinodorus grandiflorus Leaves, Inhibits Antigen-Induced Arthritis and Gout in Mice.

cis-Aconitic acid is a constituent from the leaves of Echinodorus grandiflorus, a medicinal plant traditionally used in Brazil to treat inflammatory conditions, including arthritic diseases. The present study aimed to investigate the anti-arthritic effect of cis-aconitic acid in murine models of antigen-induced arthritis and monosodium urate-induced gout. The possible underlying mechanisms of action was evaluated in THP-1 macrophages. Oral treatment with cis-aconitic acid (10, 30, and 90 mg/kg) reduced leukocyte accumulation in the joint cavity and C-X-C motif chemokine ligand 1 and IL-1ß levels in periarticular tissue. cis-Aconitic acid treatment reduced joint inflammation in tissue sections of antigen-induced arthritis mice and these effects were associated with decreased mechanical hypernociception. Administration of cis-aconitic acid (30 mg/kg p. o.) also reduced leukocyte accumulation in the joint cavity after the injection of monosodium urate crystals. cis-Aconitic acid reduced in vitro the release of TNF-α and phosphorylation of IκBα in lipopolysaccharide-stimulated THP-1 macrophages, suggesting that inhibition of nuclear factor kappa B activation was an underlying mechanism of cis-aconitic acid-induced anti-inflammatory effects. In conclusion, cis-aconitic acid has significant anti-inflammatory effects in antigen-induced arthritis and monosodium urate-induced arthritis in mice, suggesting its potential for the treatment of inflammatory diseases of the joint in humans. Additionally, our findings suggest that this compound may contribute to the anti-inflammatory effect previously reported for E. grandiflorus extracts.

Microenvironment-Induced In Situ Self-Assembly of Polymer-Peptide Conjugates That Attack Solid Tumors Deeply.

In cancer treatment, the unsatisfactory solid-tumor penetration of nanomaterials limits their therapeutic efficacy. We employed an in vivo self-assembly strategy and designed polymer-peptide conjugates (PPCs) that underwent an acid-induced hydrophobicity increase with a narrow pH-response range (from 7.4 to 6.5). In situ self-assembly in the tumor microenvironment at appropriate molecular concentrations (around the IC50 values of PPCs) enabled drug delivery deeper into the tumor. A cytotoxic peptide KLAK, decorated with the pH-sensitive moiety cis-aconitic anhydride (CAA), and a cell-penetrating peptide TAT were conjugated onto poly(ß-thioester) backbones to produce PT-K-CAA, which can penetrate deeply into solid tumors owing to its small size as a single chain. During penetration in vivo, CAA responds to the weak acid, leading to the self-assembly of PPCs and the recovery of therapeutic activity. Therefore, a deep-penetration ability for enhanced cancer therapy is provided by this in vivo assembly strategy.

Bromocatechol conjugates from a Chinese marine red alga, Symphyocladia latiuscula.

This study describes an investigation into polybromocatechol conjugates isolated from a marine red alga, Symphyocladia latiuscula (Harvey) Yamada, collected from coastal waters off Qingdao, China. We report on the isolation and characterisation of eight undescribed aconitic acid conjugates, symphyocladins R-X, including a likely solvolysis artifact of symphyocladin S, and an undescribed furanoyl conjugate, symphyocladin Y. Structure elucidation was achieved by detailed spectroscopic analysis. A plausible biosynthetic pathway linking all these co-metabolites through a cascade of quinone methide additions is proposed.

Trans-aconitic acid inhibits the growth and photosynthesis of Glycine max.

Grasses producing trans-aconitic acid, a geometric isomer of cis-aconitic acid, are often used in Glycine max rotation systems. However, the effects of trans-aconitic acid on Glycine max are unknown. We conducted a hydroponic experiment to evaluate the effects of 2.5-10 mM trans-aconitic acid on Glycine max growth and photosynthesis. The results revealed that the enhanced H2O2 production in the roots increased the membrane permeability and reduced the water uptake. These effects culminated with a reduced stomatal conductance (gs), which seems to be the main cause for a decreased photosynthetic rate (A). Due to low gs, the limited CO2 assimilation may have overexcited the photosystems, as indicated by the high production of H2O2 in leaves. After 96 h of incubation, and due to H2O2-induced damage to photosystems, a probable non-stomatal limitation for photosynthesis contributed to reducing A. This is corroborated by the significant decrease in the quantum yield of electron flow through photosystem II in vivo (ΦPSII) and the chlorophyll content. Taken together, the damage to the root system and photosynthetic apparatus caused by trans-aconitic acid significantly reduced the Glycine max plant growth.

Esterification of trans-aconitic acid improves its anti-inflammatory activity in LPS-induced acute arthritis.

trans-Aconitic acid (TAA) is an abundant constituent in the leaves of Echinodorus grandiflorus, a medicinal plant used to treat rheumatoid arthritis in Brazil. Esterification was explored as a strategy to increase lipophilicity and biopharmaceutical properties of TAA, a highly polar tricarboxylic acid. We herein report the synthesis of TAA esters via Fischer esterification with ethanol, n-butanol and n-octanol. The reaction kinetics was investigated to produce mono-, di- and tri- derivatives. Mono- and diesters of TAA were obtained as a mixture of positional isomers, whereas the triesters were recovered as pure compounds. The obtained esters were screened in a model of acute arthritis induced by the injection of LPS in the knee joint of Swiss mice. The diesters were the most active compounds, regardless of the alcohol employed in the reaction, whereas bioactivity of the derivatives improved by increasing the length of the aliphatic chain of the alcohol employed in esterification. In general, the esters showed higher potency than TAA. When administered orally to mice at doses of 0.017-172.3 µmol/Kg, the diethyl, di-n-butyl and di-n-octyl esters of TAA reduced the cellular infiltration into the knee joint, especially of neutrophils. The study identified diesters of TAA as potential useful derivatives for the management of rheumatoid arthritis and other inflammatory diseases.

A dihydrochalcone derivative and further steroidal saponins from Sansevieria trifasciata Prain.

Phytochemical investigation of the aerial parts of Sansevieria trifasciata, one of the most common Dracaenaceae plants, has resulted in the isolation of a new dihydrochalcone derivative named trifasciatine C (1), four previously unreported steroidal saponins as two pairs of inseparable regioisomers: trifasciatosides K/L (2/3), M/N (4/5), together with the known 1,2-(dipalmitoyl)-3-O-ß-D-galactopyranosylglycerol (6), aconitic acid (7), and 1-methyl aconitic acid (8). Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D nuclear magnetic resonance) and high-resolution electronspray ionization-mass spectrometry, as well as chemical methods and comparison of their spectral data with those of related compounds. Compounds 2/3 and 4/5 were evaluated for their antiproliferative activity on Hela cells, and no significant effect was observed.

Molecular control of irreversible bistability during trypanosome developmental commitment.

The life cycle of Trypanosoma brucei involves developmental transitions that allow survival, proliferation, and transmission of these parasites. One of these, the differentiation of growth-arrested stumpy forms in the mammalian blood into insect-stage procyclic forms, can be induced synchronously in vitro with cis-aconitate. Here, we show that this transition is an irreversible bistable switch, and we map the point of commitment to differentiation after exposure to cis-aconitate. This irreversibility implies that positive feedback mechanisms operate to allow commitment (i.e., the establishment of "memory" of exposure to the differentiation signal). Using the reversible translational inhibitor cycloheximide, we show that this signal memory requires new protein synthesis. We further performed stable isotope labeling by amino acids in cell culture to analyze synchronized parasite populations, establishing the protein and phosphorylation profile of parasites pre- and postcommitment, thereby defining the "commitment proteome." Functional interrogation of this data set identified Nek-related kinase as the first-discovered protein kinase controlling the initiation of differentiation to procyclic forms.

Antifungal activity of homoaconitate and homoisocitrate analogs.

Thirteen structural analogs of two initial intermediates of the L-α-aminoadipate pathway of L-lysine biosynthesis in fungi have been designed and synthesized, including fluoro- and epoxy-derivatives of homoaconitate and homoisocitrate. Some of the obtained compounds exhibited at milimolar range moderate enzyme inhibitory properties against homoaconitase and/or homoisocitrate dehydrogenase of Candida albicans. The structural basis for homoisocitrate dehydrogenase inhibition was revealed by molecular modeling of the enzyme-inhibitor complex. On the other hand, the trimethyl ester forms of some of the novel compounds exhibited antifungal effects. The highest antifungal activity was found for trimethyl trans-homoaconitate, which inhibited growth of some human pathogenic yeasts with minimal inhibitory concentration (MIC) values of 16-32 mg/mL.

Antiedematogenic activity and phytochemical composition of preparations from Echinodorus grandiflorus leaves.

The leaves of Echinodorus grandiflorus (Alismataceae) are traditionally used in Brazil to treat inflammatory conditions. The aim of the present study was to evaluate the antidematogenic activity of crude aqueous, dichloromethane and hydroethanolic extracts from E. grandiflorus leaves using the carrageenan-induced paw edema model in mice, along with of fractions enriched in diterpenes, flavonoids and hydroxycinnamoyltartaric acids (HCTA). Significant inhibitions of paw edema were elicited by the 50% and 70% EtOH extracts (1000 mg/kg, p.o.), as well as by the fractions enriched in diterpenes (70-420 mg/kg, p.o.) and flavonoids (7.2-36 mg/kg, p.o.). Isovitexin, isoorientin, trans-aconitic and chicoric acids were identified in all extracts by HPLC analysis. Trans-aconitic acid itself exhibited significant antiedematogenic effect (270 mg/kg, p.o.). The biological activity correlated positively with the contents of flavonoids and diterpenes, but negatively with HCTA concentrations, demonstrating the participation of the two classes of compounds in the antiedematogenic activity of E. grandiflorus.

Allelopathic effects of aconitic acid on wild poinsettia (Euphorbia heterophylla) and morningglory (Ipomoea grandifolia).

High infestations of alexandergrass (Brachiaria plantaginea) in experimental area have reduced seedbank of some weed species in soil at a greater degree compared to those obtained with the use of an efficient herbicide. Aconitic acid (AA) has been identified in those plants in high concentration. Thus, two experiments were carried out in the laboratory to determine the effects of pure AA on weed seed germination and on endophytic fungi in wild poinsettia (Euphorbia heterophylla) and morningglory (Ipomoea grandifolia) weed species. Doses of AA (0, 0.5, 1.0, and 2.0 mM) were introduced in agar-water 0.5% medium and weed seeds treated with and without external sterilization by sodium hypochloride. Four replications of fifty seeds of each species by treatment were sown in plastic boxes with cover and maintained in germination chamber for 12 days. Reduction in germination rate, root and stem growth were observed in both species, as well as reduction in root number in morningglory were also observed at 2.0 mM concentration of AA. An increase in number of seeds with presence of endophytic fungi was also observed in both species, independently of seed sterilization, mainly of a green type fungi coloration in wild poinsettia. Aconitic acid presents allelopathic activity and can stimulate endophytic fungi species growth in weed seeds.

Cold shock and regulation of surface protein trafficking convey sensitization to inducers of stage differentiation in Trypanosoma brucei.

Transmission of a protozoan parasite from a vertebrate to invertebrate host is accompanied by cellular differentiation. The signals from the environment that trigger the process are poorly understood. The model parasite Trypanosoma brucei proliferates in the mammalian bloodstream and in the tsetse fly. On ingestion by the tsetse, the trypanosome undergoes a rapid differentiation that is marked by replacement of the variant surface glycoprotein (VSG) coat with GPI-anchored EP and GPEET procyclins. Here we show that a cold shock of DeltaT > 15 degrees C is sufficient to reversibly induce high-level expression of the insect stage-specific EP gene in the mammalian bloodstream stages of T. brucei. The 3'-UTR of the EP mRNA is necessary and sufficient for the increased expression. During cold shock, EP protein accumulates in the endosomal compartment in the proliferating, slender, bloodstream stage, whereas the EP is present on the plasma membrane in the quiescent, stumpy, bloodstream stage. Thus, there is a novel developmentally regulated cell surface access control mechanism for a GPI-anchored protein. In addition to inducing EP expression, cold shock results in the acquisition of sensitivity to micromolar concentrations of cis-aconitate and citrate by stumpy but not slender bloodstream forms. The cis-aconitate and citrate commit stumpy bloodstream cells to differentiation to the procyclic stage along with rapid initial proliferation. We propose a hierarchical model of three events that regulate differentiation after transmission to the tsetse: sensing the temperature change, surface access of a putative receptor, and sensing of a chemical cue.

Chemical interactions of Brachiaria plantaginea with Commelina bengalensis and Acanthospermum hispidum in soybean cropping systems.

Previous results obtained in soybean-wheat rotations under no-tillage conditions showed reductions in the seedbank of the weed species Commelina benghalensis, but no alteration in the seedbank of Acanthospermum hispidum in areas infested with Brachiaria plantaginea. Analyses of the soluble fraction of B. plantaginea indicated the predominance of aconitic acid (AA) among the aliphatic acids and ferulic acid (FA) among the phenolic acids. Laboratory bioassays using C. benghalensis and A. hispidum were carried out to evaluate phytotoxic effects of pure organic acid solutions and dilute extracts of B. plantaginea on seed germination, root development, and fungal germination. Solutions of AA and FA were prepared at 0.25, 0.50, and 1.0 mM. Extracts of B. plantaginea were diluted to obtain concentrations of AA similar to those in the prepared solutions. Seeds were sown on 0.5% agar (containing AA, FA, or diluted extract) in plastic-covered receptacles and maintained in a germination chamber for 10 days. AA and FA solutions and the B. plantaginea extract reduced germination and root length, mainly of C. benghalensis. AA also stimulated the development of endophytic fungi (Fusarium solani), which had complementary adverse effects on C. benghalensis germination. FA and AA may play important roles in reducing the seedbank of some weed species, acting directly on germination and development and, indirectly, by stimulating endophytic fungi that alter germination.

Depressive symptoms and taste reactivity in humans.

Animal studies suggest that induction of depression-like states may alter preference for sweet tastants. A major goal of the present study was to search for correlations between depressive symptoms measured by the Beck Depression Inventory (BDI) and taste responses to sweet and bitter substances. Thirty-three nonclinical volunteers rated intensity and pleasantness of chocolate and vanilla milk as well as of sucrose- and quinine-soaked filter paper disks. Reactivity to citric acid (sour) and sodium chloride (salty) was also tested with the paper disk methodology. Taste detection thresholds were assessed by means of electrogustometry. A weak inverse relationship was found between the BDI scores (range: 3-33) and rated intensity of paper disks soaked in 60% sucrose. No correlations were found between depressive symptoms and intensity, pleasantness or identification of the other samples. Similarly, there was no relationship between the BDI scores and responses to chocolate and vanilla milk. BDI scores were not associated with electrogustometric thresholds. These data suggest that depressive symptoms may not influence taste reactivity in nonclinical population.

Unexpected anthracycline-mediated alterations in iron-regulatory protein-RNA-binding activity: the iron and copper complexes of anthracyclines decrease RNA-binding activity.

Anthracyclines are effective antineoplastic agents. However, the interaction of these drugs with iron (Fe) is an important cause of myocardial toxicity, limiting their therapeutic use (J Lab Clin Med 122:245-251, 1993). To overcome this limitation, it is crucial to understand how anthracyclines interact with the Fe metabolism of myocardial and neoplastic cells. Iron-regulatory proteins (IRPs) play vital roles in regulating cellular Fe metabolism via their mRNA-binding activity. We showed that doxorubicin (DOX) and its analogs interfere with tumor and myocardial cell Fe metabolism by affecting the RNA-binding activity of IRPs. Unexpectedly, experiments with the free radical scavengers, catalase, superoxide dismutase, ebselen, and Mn(III) tetrakis (4-benzoic acid) porphyrin complex, suggested that the effects of DOX on IRP-RNA-binding activity were not due to anthracycline-mediated free radical production. In contrast to previous studies, we showed that the DOX metabolite, doxorubicinol, had no effect on IRP-RNA-binding activity. Rather, the anthracycline-Fe and -copper (Cu) complexes decreased IRP-RNA-binding activity, indicating that formation of anthracycline-metal complexes may affect cellular Fe metabolism. In addition, anthracyclines prevented the response of IRPs to the depletion of intracellular Fe by chelators. This information may be useful in designing novel therapeutic strategies against tumor cells by combining chelators and anthracyclines. Interestingly, the effect of DOX on primary cultures of cardiomyocytes was similar to that observed using neoplastic cells, and particularly notable was the decrease in IRP2-RNA-binding activity. Our results add significant new information regarding the effects of anthracyclines on Fe metabolism that may lead to the design of more effective treatments.

The influence of charge clustering on the anti-HIV-1 activity and in vivo distribution of negatively charged albumins.

The substitution of human serum albumin with negatively charged molecules, such as succinic acid (Suc-HSA) or aconitic acid (Aco-HSA), resulted in proteins with potent anti-HIV activities, by binding to viral gp120 (V3 loop). The aim of the present study was to investigate whether the distribution of negative charges on the albumin backbone influences the anti-HIV activity. Therefore, we prepared albumins with clusters of negatively charged groups by coupling of heparin. The effects of this substitution on anti-HIV activity, in vivo distribution and the protein structure as compared to random succinylation were assessed. In vitro studies indicated that HSA-modified with heparin 6 or 13 kD displayed anti-HIV activity (IC50=660 and 37 nM, respectively) and exhibited affinity for gp120-V3 loop, although the activity was lower than that of Suc-HSA. Combined derivatization of HSA with heparin 13 kD and aconitic acid groups resulted in significantly increased inhibitory actions (IC50=2.8 nM). Structural analysis showed that modification of HSA with heparin did not lead to extensive unfolding of the protein, meaning that these modified proteins were still globular in structure. In contrast, succinylation of HSA resulted in a highly randomly coiled conformation. Dynamic light scattering experiments revealed that, at neutral pH, the heparin fragments attached to the protein were wrapped around the molecule rather than sticking out into the solution. In conclusion, coupling of sufficient clustered negative charges, by coupling of Hep-fragments, on HSA resulted in a clear anti-HIV activity of the protein. Yet, random distribution of anionic groups in the albumin seemed more optimal for in vitro anti-HIV activity. The higher plasma and lymphatic concentrations of Hep-HSA compared to Suc-HSA seemed more favorable for an anti-HIV activity in vivo.

[Characteristics of NADP-dependent isocitrate dehydrogenase functioning in pea leaves during salt stress]. / Nekotorye osobennosti funktsionirovaniia NADF-izotsitratdegidrogenazy list'ev gorokha pri solevom stresse.

In pea seedlings transferred to a medium containing 3% NaCl, NADP-dependent isocitrate dehydrogenase (NADP-IDH) activity in leaves increased more than twofold during the first hour, decreased, and increased again (approximately 1.5 times) by the 14th hour of exposure. Some catalytic and regulatory properties of NADP-IDH were studied using enzyme preparations purified from normal plants and plants exposed to salt stress. The results showed that Km for NADP-IDH in reactions with isocitrate and NADP decreased under stress by factors of 2 and 3, respectively. Specific features of enzyme activity regulation by citrate and trans-aconitate under these conditions were revealed. The inhibitory effects of gamma-aminobutyric acid (GABA) and 2-oxoglutarate on NADP-IDH from plants exposed to salt stress was stronger than that on the enzyme from normal plants. Glutamine and glutamate slightly activated the enzyme in both cases.