Anti-Influenza Activity of Cetraria islandica Lichen Extracts in In Vitro Experiments.

The toxicity and antiviral activity of extracts obtained by the methods of aqueous and ethanol extraction of bioactive substances from Cetraria islandica lichen as a raw material were studied. Aqueous and ethanol extracts of lichen were characterized by low toxicity with respect to the passaged MDCK cell culture and exhibited antiviral activity. The ethanol extract showed more potent in vitro antiviral activity against human A/H3N2 and avian A/H5N1 influenza viruses: in a concentration of 50 µg/ml, it suppressed replication of these viruses by 3.5 and 4 log10, respectively, while the aqueous extract inhibited replication of viruses by 2 and 6 log10, respectively, when taken in a concentration of 500 µg/ml that was 10-fold higher than the concentration of the ethanol extract.

[The effect of physiologically active compounds on the production of ethylene and the activity of polygalacturonase inhibiting protein in fruits].

The treatment of apple and banana fruits with 2-CEFA and ethacyde induced the production of ethylene and accelerated the ripening and accumulation of ACC in apple fruits. Inhibitors AOA, AVG, and CoCl2 acted at the different steps of ethylene biosynthesis, inhibited the physiological aging process and increased storage longevity. Treatment with astaxantine and BOA delayed the pick of ethylene production by fruits. The content of PGIP was correlated with intensity of ethylene production. The infection of fruits with phytopathogenic microorganisms lowered as the result of the inhibition of pathogen PG. The dynamics of PGIP activity in fruits suggests its important role in the processes of ripening.

[The effect of ethylene biosynthesis regulators on metabolic processes in the banana fruits in various physiological states].

The effects of ethylene-evolving preparations-2-chloroethylphosphonic acid (2-CEPA), the new generation binary preparation ethacide, and the specific inhibitor of ethylene biosynthesis aminooxyacetic acid (AOA)--on the ethylene evolution by banana (Musa sp.) fruits at various ripening stages and the content of protein inhibitor of polygalacturonase (PIPG), associated with prevention of fruit tissue softening, were studied. It was demonstrated that the ripening stage was of significant importance for the results of treatment with the mentioned preparations. Their effects were most pronounced in the fruits of medium ripeness. 2-CEPA and ethacide increased the ethylene evolution in banana fruits on the average by 25-30%. AOA treatment decreased the ethylene evolution in these fruits by 30%. The PIPG content in fruit pulp was insignificant; 2-CEPA almost did not change its content in banana skin, while ethacide and AOA somewhat decreased it. Consequently, the regulators of ethylene biosynthesis have a potential for optimizing the state of banana fruits during storage and sale.

Polygalacturonase-inhibiting protein is a structural component of plant cell wall.

It is generally believed that plants "evolved a strategy of defending themselves from a phytopathogen attack" during evolution. This metaphor is used frequently, but it does not facilitate understanding of the mechanisms providing plant resistance to the invasion of foreign organisms and to other unfavorable external factors, as well as the role of these mechanisms in plant growth and development. Information on processes involving one of the plant resistance factors--polygalacturonase-inhibiting protein (PGIP)--is considered in this review. The data presented here indicate that PGIP, being an extracellular leucine-rich repeat-containing protein, performs important functions in the structure of plant cell wall. Amino acid residues participating in PGIP binding to homogalacturonan in the cell wall have been determined. The degree of methylation and the mode of distribution of homogalacturonan methyl groups are responsible for the formation of a complex structure, which perhaps determines the specificity of PGIP binding to pectin. PGIP is apparently one of the components of plant cell wall determining some of its mechanical properties; it is involved in biochemical processes related to growth, expansion, and maceration, and it influences plant morphology. Polygalacturonase (PG) is present within practically all plant tissues, but the manifestation of its activity varies significantly depending on physiological conditions in the tissue. Apparently, the regulation of PG functioning in apoplast significantly affects the development of processes associated with the modification of the structure of plant cell wall. PGIP can regulate PG activity through binding to homogalacturonan. The genetically determined structure of PGIP in plants determines the mode of its interaction with an invader and perhaps is one of the factors responsible for the set of pathogens causing diseases in a given plant species.

[Cloning of polygalacturonase inhibitor protein genes from Solanum brevidens Fill].

New data were obtained for the Solanum brevidens Fill. nucleotide sequences coding for polygalacturonase inhibitor proteins (PGIPs), which are involved in plant defense against phytopathogenic fungi. Highly degenerate primers directed to the conserved regions of the known PGIP genes of tomato, kiwi, apple, carrot, and grape were used to clone four pgip genes and one pseudogene from the genome of S. brevidens, a species that is closely related to cultivated potato, forms no tubers, is highly resistant to phytopathogens, and is often employed in potato breeding. The sequenced part of the coding region of the new genes is 924 bp and codes for a protein of 308 amino acid residues (without the leader peptide). The genes were designated as pgipSbr1(1), pgipSbr1 (2). pgipSbr2, pgipSbr3, and pgipSbr4. The amino acid sequences of the S. brevidens PGIPs have 90.9-99.4% identity to each other and 94% identity to PGIP of Lycopersicon esculentum Mill., another member of the family Solanaceae. The amino acid residues differing between S. brevidens PGIPs were assumed to determine the selectivity of interactions with particular polyglucuronases of phytopathogenic fungi.

[Activity of polygalacturonase-inhibiting protein of banana fruit tissues].

The activity of polygalacturonase and the protein inhibiting this enzyme, which affected polygalacturonases of phytopathogenic fungi Verticillium dahliae and Gloesporium musarium, were detected in banana (Musa acumthata L.) fruit of cultivars Cavendish and Korolevskii. The polygalacturonase from banana fruit was inhibited by the preparations of the protein inhibitor not only from bananas but also from potato (Solanum tuberosum L.) tubers and pepper (Capsicum annuum L.) fruit.

[Activity of a proteinaceous polygalacturonase inhibitor in potato plants]. / Aktivnost' belkovogo ingibitora poligalakturonazy v rasteniiakh kartofelia.

The activity of a protein inhibitor of polygalacturonase (PIPG) was studied in potato tubers during storage and in potato leaves and stems during vegetation. The activity of PIPG in tubers varied from between seasons. The activity of PIPG during dormancy changed depending on the storage stage and temperature. As a rule, it was higher in etiolated sprouts than in the tubers. The activity of PIPG was slightly higher in leaves of adult vegetating plants than in stems and decreased by the end of vegetation. These changes in the activity of PIPG are suggested to be associated with changes in the growth rate.

[Interaction of the enzyme xylonigrine with isolated cytoplasmatic membranes of cells of potato tubers Solanum tuberosum L]. / Vzaimodeistvie fermentnogo preparata ksilonigrina s izolirovannymi tsitoplazmaticheskimi membranami kletok klubnia kartofelia Solanum tuberosum L.

The effect of the enzyme xylonigrine on isolated cytoplasmatic membranes of potato tuber cells was studied. Measurements of protein and carbohydrates in the supernatant following combined incubation and centrifugation as well as morphological characterization of microvesicles by electron microscopy demonstrated a lack of xylonigrine-induced morphological changes in microvesicles. A decrease in the protein quantity in the supernatant after incubation of membranes and xylonigrine for 2 hours at 20 degrees was found. As a result of further incubation for 6 hours the protein quantity approached the initial level. During incubation of membranes with xylonigrine for 6 hours at 40 degrees C the carbohydrate amount increased. The incubation for 2 and 6 hours at 20 degrees C did not cause any significant changes in the carbohydrate content in the supernatant.

[Change in the level of 1-aminochloropropane-1-carbonic acid. Activity of a protein inhibitor of polygalacturonase, intensity of formation of oligouronides in apples during ripening and treatment with haloethane derivatives and aminoethoxyvinylglycine]. / Izmenenie soderzhaniia 1-aminotsiklopropan-1-karbonovoi kisloty, aktivnosti belkovogo ingibitora poligalakturonazy, intensivnosti obrazovaniia oligouronidov v plodakh iabloni pei sozrevanii i deistvii galaétanproizvodnykh i aminoétoksivinilglitsina.

We studied changes in the intensity of ethylene release and accumulation of 1-aminocyclopropane-1-carboxylic acid during ripening of two apple varieties characterized by various physiological states and treated with halothane derivatives and L-alpha-(2-aminoethoxyvinyl)-glycine. We observed changes in activity of the protein polygalacturonase inhibitor in the fruit tissue and accumulation of oligouronides. The data suggest that pretreatment with the inhibitor of 1-aminocyclopropane-1-carboxylic acid synthase affects ethylene release, accumulation of 1-aminocyclopropane-1-carboxylic acid, activity of the protein polygalacturonase inhibitor, and potential intensity of oligouronide formation in apple fruits and tissues.

[Role of a protein inhibitor of polygalacturonase in ripening of apples and their resistance of infection with Monilia fructigena, the causative agent of fruit rot]. / Rol' belkovogo ingibitora poligalakturonazy v sozrevanii plodov iabloni i ikh ustoichivosti k porazheniiu vozbuditelem plodovoi gnili Monilia fructigena.

We investigated the dynamics of the activity of the polygalacturonidase inhibitor protein (PGIP) in apple fruits of six varieties differing in ripening time and correlated it with the degree of damage by the causative agent of fruit rot, Monilia fructigena. The apple varieties studied differed significantly in PGIP activity and degree of damage by Monilia fructigena. The rate of dissemination over fruit tissues was inversely related to PGIP activity. The resistance of apples to M. fructigena increased with ripening. The simultaneous increase in PGIP activity suggests its important role in the reduction of apple damage by fruit rot.

[Structural study of Eremurus glucomannans by electron microscopic and roentgenographic methods]. / Izuchenie stroeniia gliukomannanov éremusov metodami élektronnoi mikroskopii i rentgenografii.

By electron microscopy and roentgenography glucomannanes from four species of Eremurus have been examined and shown to be polymorphic. Deacetylated glucomannane produces a lamellar form with a high degree of crystallinity. Partially acetylated glucomannane produces a fibrillar form representing a poorly ordered structure with a spaced (4.4 A) position of chains going in the same direction. In plants glucomannane can also exist as fibrils. The factors determining the formation of a certain supramolecular form are acetyl substitutes in the chain of the polysaccharide and the degree of its polymerization. The effect of the supramolecular structure on the properties and biological function of glucomannanes is discussed.

[A protein inhibitor of polygalacturonase in apple fruits treated with aminoethoxyvinylglycine and cobalt chloride]. / Belkovyi ingibitor poligalakturonazy v plodakh iabloni, obrabotannykh aminoetoksivinilglitsinomi khloristym kobal'tom.

Ethylene evolution changes were monitored during storage of apple fruits (Malus domestica Borkh., winter variety Mantuanskoe) treated with aminoethoxyvinylglycine and CoCl2. The storage of fruits was shown to be accompanied by changes in the activity of a protein inhibitor of polygalacturonase (PIPG). This inhibitor has been previously isolated from apple fruit tissues. The protein inhibitor of polygalacturonase was also shown to inhibit the activity of an enzyme produced by certain nonpathogenic fungi. The role of PIPG in apple fruit resistance to these fungi is discussed.

[Effect of proteinaceous polygalacturonase inhibitors from apple seed tissue on an enzyme isolated from phytopathogenic fungi]. / Deistvie belkovogo ingibitora poligalakturnoazy iz tkanei plodov iabloni na ferment, vydeliaemyi fitopathogennymi gribami.

A protein polygalacturonidase inhibitor isolated from fruit of the apple varieties Antonovka and Mantuanskoe differently affects the polygalacturonidases of different phytopathogenic fungi. Three groups of fungi were recognized by the sensitivity of their polygalacturonidases to the inhibitory effect. Storage of apples after harvesting is accompanied by changes in the inhibitor activity, and the time pattern of these changes depends on the variety. An increase in the inhibitor activity occurs concurrently with the elevation in ethylene release characteristic of the stage of elevated respiration (a climacteric increase). The data suggest that a decrease in the apple fruit resistance to microbes at the end of the storage period is related, along with other reasons, to a change in the activity of the protein polygalacturonidase inhibitor.

[Effects of treatment with a composite preparation (2-chloroethylphosphonic acid and methacide) or butylated hydroxyanisole on ethylene release in apples]. / Vliianie obrabotki kompleksnym preparatom (2-khlorétilfosfonovaia kislota + metatsid) i butiloksianizolom na vydelenie étilena plodami iabloni.

We studied the effect of a Russian composite preparation (2-chloroethylphosphonic acid and methacide) and butylated hydroxyanisole on ethylene release in whole fruit and peel disks of two apple cultivars, Antonovka obyknovennaya (Antonovka) and Simirenko's rennet (Simirenko). Treatment with the composite preparation was followed by an increase in ethylene release from whole apples and peel disks. The development of microbial infection (fruit rot) in whole apples became less pronounced after the treatment. Treatment of whole apples with the antioxidant butylated hydroxyanisole (BHA) increased the intensity of ethylene release during the first subsequent days; thereafter, ethylene release decreased and was 10-15% lower than in the control on days 10-12. In model experiments, BHA decreased ethylene release from apple peel disks below control levels as early as on day 1 after the treatment. Antonovka apples gave quick responses to the treatment. In the late-ripening Simirenko apples, the response persisted for a longer period. Our results suggest that treatment with physiologically active preparations affects ethylene release, ripening, and preservation of apples in storage.

[The effect of the substance exin on development of microbial infections and isolation of ethylene in plants]. / Vliianie preparata ekzin na razvitie mikrobial'noi infektsii i vydelenie étilena u rastenii.

Effects of Exin on infection of tomato, potato, and cabbage plants with Pseudomonas solanacearum and Erwinia carotovora and a fungus Sclerotium rolfsii were studied. The treatment of infected plants with Exin caused no significant effect on the development of the disease. Treatment with streptomycin as a standard for comparison completely inhibited the growth of these microorganisms. Pretreatment with Exin one to eight days before infecting inhibited the development of diseases. The numbers of tomato and potato plants damaged among those infected with P. solanacearum were lower by 10 and 35% respectively. In field experiments (350 plants per variant), treatment with Exin decreased the development of wilt caused by S. rolfsii and P. solanacearum and rot caused by E. carotovora. Treatment with Exin activated the release of ethylene for not less than 30 days. Possible mechanisms of the effects of Exin are discussed.

GacS-dependent regulation of enzymic and antifungal activities and synthesis of N-acylhomoserine lactones in rhizospheric strain Pseudomonas chlororaphis 449.

Pseudomonas chlororaphis strain 449 isolated from the rhizosphere of maize suppresses numerous plant pathogens in vitro. The strain produces phenazine antibiotics and synthesizes at least three types of quorum sensing signaling molecules, N-acylhomoserine lactones. Here we have shown that the rhizospheric P. chlororaphis strains 449, well known strain 30-84 as well as two other P. chlororaphis strains exhibit polygalacturonase activity. Using mini-Tn5 transposon mutagenesis, four independent mutants of strain P. chlororaphis 449 with insertion of mini-Tn5 Km2 in gene gacS of two-component GacA-GacS system of global regulation were selected. All these mutant strains were deficient in production of extracellular proteinase(s), phenazines, N-acylhomoserine lactones synthesis, and did not inhibit the growth of G(+) bacteria in comparison with the wild type strain. The P. chlororaphis 449-06 gacS (-) mutant studied in greater detail was deficient in polygalacturonase, pectin methylesterase activities, swarming motility and antifungal activity. It is the first time the involvement of GacA-GacS system in the regulation of enzymes of pectin metabolism, polygalacturonase and pectin methylesterase, was demonstrated in fluorescent pseudomonads.

[Quorum-sensing regulation in soil pseudomonads].

228 strains of soil and rhizosphere pseudomonads isolated in different geographic zones were screened, with the use of two tester systems, for the capacity to produce N-acetyl-homoserine lactones (AHLs), which are autoinducers involved in quorum-sensing (QS) regulation. AHL production was found in 11.4% of the strains investigated. In five Pseudomonas chlororaphis strains shown to be active AHL producers and chosen for further study, PCR identified two QS systems that involved the phzI, phzR, csaI, and csaR genes; this finding suggests the conservative nature of these regulation systems in P. chlororaphis. Strain P. chlororaphis 449, chosen as a model object and studied in greater detail, produced three AHL species including N-butanoyl-homoserine lactone and N-hexanoyl-homoserine lactone. This strain produced three types of phenazine antibiotics, as well as siderophores and cyanide; it also exhibited antagonistic properties toward a wide spectrum of phytopathogenic fungi. The phzI and csaI genes, coding for synthases of AHLs of two types, were cloned and sequenced; mutants with knocked-out phzI and csal genes were obtained. With the use of transposon mutagenesis and the gene substitution method, mutations were obtained in the global expression regulator genes gacS, coding for the GacA-GacS regulation system kinase, and rpoS, coding for the sigma S subunit of RNA polymerase. The effect of these mutations on the AHL synthesis and on the regulation of various metabolic processes in P. chlororaphis was studied.

[Microorganism in the hyphae of mycorrhiza-forming fungus]. / Mikroorganizm v gifakh mikorizoobrazuiushchego griba

A microorganism with the cell wall and cytoplasmic membrane was found when the endotrophic mycorrhiza of pea was studied by electron microscopy. The wall of the microorganism was in a close contact with the cytoplasm of the fungus. No changes were found in the ultrastructure of the fungus and microorganism caused by their interaction.

Plasma membrane-bound mechanisms of signal transduction in the control of plant dormancy and resistance.

Data on membrane-bound biochemical mechanisms of control of plant dormancy and resistance to phytopathogens are discussed. Phytohormones are involved in the control of plant dormancy by the modification of activity of membrane-bound enzymes and ion channels. Similar constituents of the plasma membrane are influenced by fungal extracellular metabolites. Proposed interconnections between plasmalemma-bound signaling mechanisms responsible for plant resistance to infection and dormancy regulation are illustrated by a scheme.

[Electrophoretic study of Potato tuber plasmolemmal proteins]. / Elektroforeticheskoe issledovanie belkov plazmalemmy klubnei kartofelia.

The number and qualitative content of proteins extracted from potato tuber plasmolemma by buffer solutions of various ionic strengths and the non-ionic detergent Triton X-100 were investigated. It was shown that treatment with the buffer solutions of various ionic strengths results in separation of various amounts of proteins from the membranes. The proteins extracted at various ionic strengths differ in their electrophoretic mobility and the lipo- and glycoprotein sets. The extraction of the bulk of peripheral proteins by buffer solutions does not affect the vesicular structure and the three-layer structure of the vesicles in the plasmolemmal preparation. On the contrary, Triton X-100 has a destructive effect on the plasmolemmal vesicles. The amount of protein extracted with Triton X-100 is relatively low and does not increase with the increase in the detergent concentration from 1% up to 10%. Pretreatment of the preparation with buffer solutions decreases the amount of protein extracted by Triton X-100 irrespective of the ionic strength of the buffer. The electrophoregrams of the proteins extracted by the buffer solutions and Triton X-100 revealed that the detergent can dissolve both structural and peripheral proteins of the plasmolemma. Treatment of plasmolemma with buffer solutions causes separation of hydrophylic proteins from the membranes and brings about changes in the properties of the membrane-bound proteins.