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941.
Phytohormones from rhizobacterial origin have been linked to their phytostimulation potential. However, while studying the
efficacy of plant growth promoting bacteria, focus has always been on a single hormone. The role of plant hormones often overlay
and they mutually modulate their effect. In current study focus was on the role of two hormones (cytokinins and indole acetic
acid) in phytostimulation by rhizobacteria. Endogenous rhizosphere bacteria were isolated and screened for the presence of
phytohormones. Bacterial strains from three different genera (Pseudomonas, Bacillus and Azospirillum) were screened positive for cytokinins and IAA. Phytohormones were simultaneously determined in SPE purified bacterial extract
by ultra performance liquid chromatography (UPLC) coupled to a tandem mass spectrometer through electrospray interface. Cytokinins
and IAA were determined in positive and negative mode, respectively with MRM scan. Zeatin, zeatin riboside and dihydrozeatin
riboside were detected and quantified in the selected strains. Significant positive correlation between cytokinins and IAA
in bacterial culture and plant endogenous hormones (r = 0.933 and r = 0.983; P = 0.01, respectively) was observed. However, strains with high IAA to cytokinins ratio could hardly enhance in-planta cytokinins, indicating antagonistic relation between the two hormones. Significant correlation of cytokinin with shoot length
(r = 0.797; P = 0.01), fresh weight (r = 0.685; P = 0.01) and dry weight (r = 0.704; P = 0.01) was reported under axenic conditions. Bacterial IAA was correlated negatively to root length (r = 0.853; P = 0.01) and positively correlated to the number of roots (r = 0.964; P = 0.01). In natural conditions maximum increase in spike length (33%), number of tillers (71%) and weight of seeds (39%)
was documented at final harvest in bacterially inoculated plants. 相似文献
942.
Electricity generation in a microbial fuel cell (MFC) using carbon monoxide (CO) or synthesis gas (syngas) as a carbon source has been demonstrated recently. A major challenge associated with CO or syngas utilization is the mass transfer limitation of these sparingly soluble gases in the aqueous phase. This study evaluated the applicability of a dense polymer silicone membrane and thin wall silicone tubing for CO mass transfer in MFCs. Replacing the sparger used in our previous study with the membrane systems for CO delivery resulted in improved MFC performance and CO transformation efficiency. A power output and CO transformation efficiency of up to 18 mW (normalized to anode compartment volume) and 98%, respectively, was obtained. The use of membrane systems offers the advantage of improved mass transfer and reduced reactor volume, thus increasing the volumetric power output of MFCs operating on a gaseous substrate such as CO. 相似文献
943.
The phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was found to be rapidly mineralized in
an agricultural soil in France that had been periodically exposed to IPU. Enrichment cultures from samples of this soil isolated
a bacterial strain able to mineralize IPU. 16S rRNA sequence analysis showed that this strain belonged to the phylogeny of
the genus Sphingomonas (96% similarity with Sphingomonas sp. JEM-14, AB219361) and was designated Sphingomonas sp. strain SH. From this strain, a partial sequence of a 1,2-dioxygenase (catA) gene coding for an enzyme degrading catechol putatively formed during IPU mineralization was amplified. Phylogenetic analysis
revealed that the catA sequence was related to Sphingomonas spp. and showed a lack of congruence between the catA and 16S rRNA based phylogenies, implying horizontal gene transfer of the catA gene cluster between soil microbiota. The IPU degrading ability of strain SH was strongly influenced by pH with maximum degradation
taking place at pH 7.5. SH was only able to mineralize IPU and its known metabolites including 4-isopropylaniline and it could
not degrade other structurally related phenylurea herbicides such as diuron, linuron, monolinuron and chlorotoluron or their
aniline derivatives. These observations suggest that the catabolic abilities of the strain SH are highly specific to the metabolism
of IPU. 相似文献
944.
Bioisosteric approach to the discovery of imidazo[1,2-a]pyrazines as potent Aurora kinase inhibitors
Meng Z Kulkarni BA Kerekes AD Mandal AK Esposite SJ Belanger DB Reddy PA Basso AD Tevar S Gray K Jones J Smith EB Doll RJ Siddiqui MA 《Bioorganic & medicinal chemistry letters》2011,21(1):592-598
Our continued effort toward the development of the imidazo[1,2-a]pyrazine scaffold as Aurora kinase inhibitors is described. Bioisosteric approach was applied to optimize the 8-position of the core. Several new potent Aurora A/B dual inhibitors, such as 25k and 25l, were identified. 相似文献
945.
Zeng H Belanger DB Curran PJ Shipps GW Miao H Bracken JB Arshad Siddiqui M Malkowski M Wang Y 《Bioorganic & medicinal chemistry letters》2011,21(19):5870-5875
A series of substituted imidazo[1,2-a]pyrazin-8-amines were discovered as novel breast tumor kinase (Brk)/protein tyrosine kinase 6 (PTK6) inhibitors. Tool compounds with low-nanomolar Brk inhibition activity, high selectivity towards other kinases and desirable DMPK properties were achieved to enable the exploration of Brk as an oncology target. 相似文献
946.
Avasthi TS Kumar N Baddam R Hussain A Nandanwar N Jadhav S Ahmed N 《Journal of bacteriology》2011,193(16):4272-4273
Uropathogenic Escherichia coli (UPEC) causes serious infections in people at risk and has a significant environmental prevalence due to contamination by human and animal excreta. In developing countries, UPEC assumes importance in certain dwellings because of poor community/personal hygiene and exposure to contaminated water or soil. We report the complete genome sequence of E. coli strain NA114 from India, a UPEC strain with a multidrug resistance phenotype and the capacity to produce extended-spectrum beta-lactamase. The genome sequence and comparative genomics emanating from it will be significant in under-standing the genetic makeup of diverse UPEC strains and in boosting the development of new diagnostics/vaccines. 相似文献
947.
948.
Rider MH Hussain N Dilworth SM Storey JM Storey KB 《Journal of insect physiology》2011,57(11):1453-1462
Winter survival for many insects depends on cold hardiness adaptations as well as entry into a hypometabolic diapause state that minimizes energy expenditure. We investigated whether AMP-activated protein kinase (AMPK) could be involved in this adaptation in larvae of two cold-hardy insects, Eurosta solidaginis that is freeze tolerant and Epiblema scudderiana that uses a freeze avoidance strategy. AMPK activity was almost 2-fold higher in winter larvae (February) compared with animals collected in September. Immunoblotting revealed that phosphorylation of AMPK in the activation loop and phosphorylation of acetyl-CoA carboxylase (ACC), a key target of AMPK, were higher in Epiblema during midwinter whereas no seasonal change was seen in Eurosta. Immunoblotting also revealed a significant increase in ribosomal protein S6 phosphorylation in overwintering Epiblema larvae, and in both Eurosta and Epiblema, phosphorylation of eukaryotic initiation factor 4E-binding protein-1 dramatically increased in the winter. Pyruvate dehydrogenase (PDH) E1α subunit site 1 phosphorylation was 2-fold higher in extracts of Eurosta larvae collected in February versus September while PDH activity decreased by about 50% in Eurosta and 80% in February Eurosta larvae compared with animals collected in September. Glycogen phosphorylase phosphorylation was 3-fold higher in Epiblema larvae collected in February compared with September and also in these animals, triglyceride lipase activity increased by 70% during winter. Overall, our study suggests a re-sculpting of metabolism during insect diapause, which shifted to a more catabolic poise in freeze-avoiding overwintering Epiblema larvae, possibly involving AMPK. 相似文献
949.
Aruna C Bhagwat VR Madhusudhana R Sharma V Hussain T Ghorade RB Khandalkar HG Audilakshmi S Seetharama N 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(8):1617-1630
Shoot fly is one of the most important pests affecting the sorghum production. The identification of quantitative trait loci
(QTL) affecting shoot fly resistance enables to understand the underlying genetic mechanisms and genetic basis of complex
interactions among the component traits. The aim of the present study was to detect QTL for shoot fly resistance and the associated
traits using a population of 210 RILs of the cross 27B (susceptible) × IS2122 (resistant). RIL population was phenotyped in
eight environments for shoot fly resistance (deadheart percentage), and in three environments for the component traits, such
as glossiness, seedling vigor and trichome density. Linkage map was constructed with 149 marker loci comprising 127 genomic-microsatellite,
21 genic-microsatellite and one morphological marker. QTL analysis was performed by using MQM approach. 25 QTL (five each
for leaf glossiness and seedling vigor, 10 for deadhearts, two for adaxial trichome density and three for abaxial trichome
density) were detected in individual and across environments. The LOD and R
2 (%) values of QTL ranged from 2.44 to 24.1 and 4.3 to 44.1%, respectively. For most of the QTLs, the resistant parent, IS2122
contributed alleles for resistance; while at two QTL regions, the susceptible parent 27B also contributed for resistance traits.
Three genomic regions affected multiple traits, suggesting the phenomenon of pleiotrophy or tight linkage. Stable QTL were
identified for the traits across different environments, and genetic backgrounds by comparing the QTL in the study with previously
reported QTL in sorghum. For majority of the QTLs, possible candidate genes were identified. The QTLs identified will enable
marker assisted breeding for shoot fly resistance in sorghum. 相似文献
950.
This study investigated the effects of cinnamic acid (CA) on growth, biochemical and physiological responses of Lactuca sativa L. CA (0.1, 0.5, 1.0 and 1.5 mM) treatments decreased plant height, root length, leaf and root fresh weight, but it did not affect the leaf water status. CA treatment (1.5 mM) significantly reduced Fv, Fm, photochemical efficiency of PSII (Fv/Fm) and quantum yield of PSII (ΦPSII) photochemistry in L. sativa. The photochemical fluorescence quenching (qP) and non-photochemical quenching (NPQ) were reduced after treatment with 1.5 mM CA. Fraction of photon energy absorbed by PS II antennae trapped by “open” PS II reaction centers (P) was reduced by CA (1.5 mM) while, portion of absorbed photon energy thermally dissipated (D) and photon energy absorbed by PSII antennae and trapped by “closed” PSII reaction centers (E) was increased. Carbon isotope composition ratios (δ13C) was less negative (−27.10) in CA (1.5 mM) treated plants as compared to control (−27.61). Carbon isotope discrimination (Δ13C) and ratio of intercellular CO2 concentration (ci/ca) from leaf to air were also less in CA treated plants. CA (1.5 mM) also decreased the leaf protein contents of L. sativa as compared to control. 相似文献