Induction of defense-related proteins by mixtures of plant growth promoting endophytic bacteria against Banana bunchy top virus

Rhizosphere and endophytic bacterial isolates from the roots and corms of banana were tested for their biocontrol efficiency against Banana bunchy top virus (BBTV). Molecular characterization using RAPD and microsatellite markers revealed genomic variability in the endophytic Pseudomonas and Bacillus isolates. Bio-formulations of mixtures of the rhizobacterial isolate Pseudomonas fluorescens (Pf1) and endophytic Bacillus spp. (EPB22) were effective in reducing the incidence of BBTV under green-house (80%) and field conditions (52%). Reduction in virus titer (0.64) was noticed in the plants treated with compatible mixtures of rhizobacterial and endophytic bacterial isolates as evidenced by ELISA, in comparison to control plants (1.69). In addition to disease control, a significant increase in the yield (53.33%) was noticed in the bacterized plants when compared to the control plants. Pathogenesis-related (PR) proteins, chitinase and β-1,3-glucanase and defense-related proteins, peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase and phenolic compounds were significantly activated in the bacterized plants, thus inducing resistance against bunchy top virus. Populations of endophytic bacteria also remained high and stable throughout the growing period. Thus, application of mixtures of rhizosphere and endophytic bacteria increases yield and has a potential role in inducing resistance against Banana bunchy top virus.     

Zebrafish Rohon-Beard Neuron Development: Cdk5 in the Midst

Cyclin-dependent kinase 5 (cdk5) is a proline-directed serine/threonine kinase that is activated mostly by association with its activators, p35 and p39. Initially projected as a neuron-specific kinase, cdk5 is expressed ubiquitously and its kinase activity solely depends on the presence of its activators, which are also found in some non-neuronal tissues. As a multifunctional protein, cdk5 has been linked to axonogenesis, cell migration, exocytosis, neuronal differentiation and apoptosis. Cdk5 plays a critical role in functions other than normal physiology, especially in neurodegeneration. Its contribution to both normal physiological as well as pathological processes is mediated by its specific substrates. Cdk5-null mice are embryonically lethal, therefore making it difficult to study precisely what cdk5 does to the nervous system at early stages of development, be it neuron development or programmed cell death. Zebrafish model system bypasses the impediment, as it is amenable to reverse genetics studies. One of the functions that we have followed for the cdk5 ortholog in zebrafish in vivo is its effect on the Rohon-Beard (RB) neurons. RB neurons are the primary sensory spinal neurons that die during the first two days of zebrafish development eventually to be replaced by the dorsal root ganglia (DRG). Based on ours studies and others’, here we discuss possible mechanisms that may be involved in cdk5’s role in RB neuron development and survival.     

Synthesis and biological applications of ionic triphenyltin(IV) chloride carboxylate complexes with exceptionally high cytotoxicity

The reaction of N-phthaloylglycine (P-GlyH), N-phthaloyl-l-alanine (P-AlaH), and 1,2,4-benzenetricarboxylic 1,2-anhydride (BTCH) with triethylamine led to the formation of the corresponding ammonium salts [NHEt(3)][P-Gly] (1), [NHEt(3)][P-Ala] (2) and [NHEt(3)][BTC] (3) in very high yields. The subsequent reaction of 1-3 with triphenyltin(iv) chloride (1?:?1) yielded the compounds [NHEt(3)][SnPh(3)Cl(P-Gly)] (4), [NHEt(3)][SnPh(3)Cl(P-Ala)] (5), and [NHEt(3)][SnPh(3)Cl(BTC)] (6), respectively. The molecular structure of 4 was determined by X-ray diffraction studies. The cytotoxic activity of the ammonium salts (1-3) and the triphenyltin(iv) chloride derivatives (4-6) were tested against human tumor cell lines from five different histogenic origins: 8505C (anaplastic thyroid cancer), A253 (head and neck cancer), A549 (lung carcinoma), A2780 (ovarian cancer) and DLD-1 (colon cancer). Triphenyltin(iv) chloride derivatives (4-6) show very high activity against these cell lines while the ammonium salts of the corresponding carboxylic acids (1-3) are totally inactive. The most active compound is 4 which is 50 times more active than cisplatin. Compound 4 is found to induce apoptosis via extrinsic pathways on DLD-1 cell lines, probably by accumulation of caspases 2, 3 and 8. Furthermore, compound 4 seems to cause disturbances in G1 and G2/M phases in cell cycle of DLD-1 cell line.     

Tetra substituted thiophenes as anti-inflammatory agents: exploitation of analogue-based drug design

A series of 17 novel tetra substituted thiophenes was designed, synthesized, and screened for anti-inflammatory activity in carrageenin induced rat paw edema model, an acute in vivo model. The lead molecule selected was Tenidap, a dual COX/LOX inhibitor. Compounds I (43%), III (60%), IV (60%), and VIII (64%) showed moderate to good anti-inflammatory activity. The best candidate among the whole series was VIII, which gave 64% protection to the inflamed paw. The side chain of candidate VIII had resemblance to that of Romazarit, a DMARD, which was withdrawn due to its toxicity profile. A probable reason for the metabolic stability of the proposed side chain not having the possibility of generating peroxy type radicals or acrylic acid moieties, unlike Romazarit, is discussed. The biological activity exhibited by the three designed series was in the order of methyl amino series > ethyl amino series > carbethoxy amino series. The –(CO)–CH₂–COOR side chain at the fifth position as in candidate VIII, the methyl amino group at the second position, and the ester at the third position of the thiophene can be considered as a three-point pharmacophore for designing better anti-inflammatory agents. The present study is a classical example of the exploitation of an analogue based drug design, which culminated in the development of good anti-inflammatory agents that have the potential of becoming dual inhibitors.     

Cyclin-dependent kinase 5 influences Rohon-Beard neuron survival in zebrafish

Cyclin-dependent kinase 5 (cdk5), a member of the cyclin-dependent kinase family, is expressed predominantly in post-mitotic cell populations. Unlike the other cdks, cdk5 is abundant and most active in differentiated neurons. Here, we describe the function of a cdk5 ortholog in zebrafish. Cdk5 catalytic activity is meager but present in early stages of development. However, at 24 h post-fertilization (hpf), the activity is remarkably higher and continues to be high through 48 and 72 hpf. Knocking down cdk5 by micro-injection of a specific siRNA resulted in decreased cdk5 protein level accompanied by reduced kinase activity. In the cdk5 siRNA-injected embryos, the number of primary sensory Rohon-Beard (RB) neurons was significantly reduced and there were more apoptotic cells in the brain. These phenotypes were rescued by co-injection of cdk5 mRNA. Within the first two days of development, RB neurons undergo apoptosis in zebrafish. To examine whether cdk5 has a role in RB neuron survival, cdk5 mRNA was injected into the one- to two-cell embryos. In these embryos, RB neuron apoptosis was inhibited compared with the uninjected control embryos. These results suggest that in zebrafish, cdk5 influences RB neuron survival and potentially regulates early neuronal development.     

Effect of stalk damage on growth and yield of certain maize cultivars by the maize stalk borer Chilo partellus

The effects of different degrees of stem tunneling caused by different levels of artificial infestation by the larvae of Chilo partellus (Swinhoe) on growth and yield of 4 maize cultivars were studied. The susceptible Inbred A suffered much more tunneling than ICZ1-CM, ICZ2-CM and Katumani Composite B. This tunneling influenced significantly the plant growth of all the four cultivars. There was a significant negative correlation between tunneling and yield for the cultivars Inbred A and Katumani Composite B, but such a relationship was not significant for ICZ1-CM and ICZ2-CM. Such differences in the relationships between tunneling and yield among the 4 cultivars are due to different degrees of tunneling caused by C. partellus larvae to the plants of these cultivars.

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Résumé L'étude a porté sur la croissance et la production avec différents niveaux de minage des tiges de 4 cultivars de maïs, lors de divers degrés de contamination artificielle par des chenilles de C. partellus. Le cultivar sensible Inbred A souffre plus des mines de C. partellus que ICZ1-CM, ICZ2-CM et Katumani composite B. Les mines influent significativement sur la croissance des 4 cultivars. Il y a une corrélation négative significative entre le minage des tiges et la production pour les cultivars Inbred A et Katumani composite B, mais la relation n'est pas significative pour ICZ1-CM et ICZ2-CM. Les différences entre le minage des tiges et la récolte des 4 cultivars sont dues aux différents degrés de minage des tiges de ces cultivars par C. partellus.

     

Immunochemical evidence of phosphorylation of a new 23K basic protein in rat brain myelin

Myelin from developing rat brain (8–44 day-old rat) was incubated in vitro with [-³²P]ATP to determine how many basic proteins were phosphorylated. Myelin proteins were separated by polyacrylamide gel electrophoresis and transferred to nitrocellulose sheets. The nitrocellulose sheets were stained with antisera to human basic protein by the immunoblot technique. Five basic proteins with molecular weights of 23K, 21.5K, 18.5K, 17K, and 14K were distinctly immunostained. These basic proteins were found to be phosphorylated when the same nitrocellulose sheets were exposed to x-ray film. The in vitro phosphorylation of 23K and 21.5K basic proteins appear to decrease with maturation of the brain. The result of this study suggests that intense phosphorylation of various forms of basic proteins, in particular 23K and 21.5K basic proteins, during the initial stages of myelin formation, may play a pivotal role in the compaction of myelin membrane.     

Electron Microscopic Immunocytochemical Localization of Myelin Proteolipid Protein and Myelin Basic Protein to Oligodendrocytes in Rat Brain During Myelination

Electron microscopic immunocytochemical studies were carried out to localize myelin basic protein and myelin proteolipid protein during the active period of myelination in the developing rat brain using antisera to purified rat brain myelin proteolipid protein and large basic protein. The anti-large basic protein serum was shown by the immunoblot technique to cross-react with all five forms of basic protein present in the myelin of 8-day-old rat brain. Basic protein was localized diffusely in oligodendrocytes and their processes at very early stages in myelination. The immunostaining for basic protein was not specifically associated with any subcellular structures or organelles. The ultrastructural localization of basic protein suggests that it may be involved in fusion of the cytoplasmic faces of the oligodendrocyte processes during compaction of myelin. Immunoreactivity in the oligodendrocyte and myelin due to proteolipid protein appeared at a later stage of myelination than did that due to basic protein. Staining for proteolipid protein in the oligodendrocyte was restricted to the membranes of the rough endoplasmic reticulum, the Golgi apparatus, and apparent Golgi vesicles. The early, uncompacted periaxonal wrappings of oligodendrocyte processes were well stained with antiserum to large basic protein whereas staining for proteolipid protein was visible only after the compaction of myelin sheaths had begun. Our evidence indicates that basic protein and proteolipid protein are processed differently by the oligodendrocytes with regard to their subcellular localization and their time of appearance in the developing myelin sheath.     

Metabolic studies on myelin. Evidence for a precursor role of a myelin subfraction

Myelin prepared from brain tissue of the developing rat (15 days post partum) can be separated into several subfractions. These are (1) ;myelin-like' and ;purified myelin', by the technique of Davison and co-workers (Agrawal et al., 1970b) and (2) ;membrane fraction,' ;light myelin' and ;heavy myelin' by the discontinuous-sucrose-gradient procedure described in the present paper. ;Myelin-like' and ;membrane-fraction' subfractions appear to be similar in chemical properties, but different in detailed morphology by electron microscopy. Both fractions are related to myelin, on the basis of demonstrable myelin basic protein by polyacrylamide-gel electrophoresis in sodium dodecyl sulphate and the presence of a myelin-marker enzyme, 2':3'-cyclic nucleotide 3'-phosphohydrolase. These two fractions have a low lipid content (17% for ;myelin-like' and 40% for ;membrane-fraction' subfractions) compared with myelin (67-72%). No cerebroside was detected in these two fractions, whereas cerebrosides are a major component of myelin itself. The administration of [2,3-(3)H]tryptophan to young rats results in more rapid incorporation into proteins of the ;myelin-like' and ;membrane-fraction' subfractions when compared with incorporation into myelin. Data are presented which are consistent with a precursor-product relationship for conversion of ;myelin-like' and ;membrane-fraction' subfractions into myelin.     

Methoxyspheroidene and methoxyspheroidenone,two carotenoids from Rhodopseudomonas spheroides

Two new carotenoids isolated from Rhodopseudomonas spheroides (Rhodospirillaceae) have been identified as methoxyspheroidene (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7$\text{,}\text{?}$8′-hexahydro-ψ,ψ-carotene) obtained from anaerobic cultures and methoxyspheroidenone (1,1′-dimethoxy-3,4-didehydro-1,2,1′,2′,7′,8′-hexahydro-ψ,ψ-caroten-2-one) recovered from aerobic cultures.