Differentiation of the American and Oriental Maydeae Accessions Using the Maize Simple Sequence Repeat (SSR) Markers

The present study evaluated the utility of maize microsatellite markers in genotype differentiation and analysis of genetic diversity among the Oriental Maydeae accessions (Coix aquatica and Chionachne koenigii) vis-à-vis the American Maydeae (maize, teosintes and maize-teosinte derivatives). Analysis of 27 microsatellite loci distributed throughout the maize genome led to the detection of 89 SSR alleles at average of 3.30 per locus. Polymorphism information content (PIC) values and observed genetic distances showed the existence of large variability among the various accessions. The maize SSR markers, particularly nc013, phi059, bnlg1523 and umc1014, were highly effective in differentiating the Oriental Maydeae accessions from the American Maydeae. Cluster analysis and Principal Component Analysis based on the SSR data clearly indicated significant genetic divergence between the Oriental Maydeae and the American Maydeae accessions, as well as between Coix aquatica and Chionachne koenigii. Molecular analyses would be valuable in gaining a better understanding of genera belonging to the Oriental Maydeae, the lesser known wild relatives of maize.     

Functional characterization of ecdysone receptor gene switches in mammalian cells

Regulated expression of transgene is essential in basic research as well as for many therapeutic applications. The main purpose of the present study is to understand the functioning of the ecdysone receptor (EcR)-based gene switch in mammalian cells and to develop improved versions of EcR gene switches. We utilized EcR mutants to develop new EcR gene switches that showed higher ligand sensitivity and higher magnitude of induction of reporter gene expression in the presence of ligand. We also developed monopartite versions of EcR gene switches with reduced size of the components that are accommodated into viral vectors. Ligand binding assays revealed that EcR alone could not bind to the nonsteroidal ligand, RH-2485. The EcR's heterodimeric partner, ultraspiracle, is required for efficient binding of EcR to the ligand. The essential role of retinoid X receptor (RXR) or its insect homolog, ultraspiracle, in EcR function is shown by RXR knockdown experiments using RNAi. Chromatin immunoprecipitation assays demonstrated that VP16 (activation domain, AD):GAL4(DNA binding domain, DBD):EcR(ligand binding domain, LBD) or GAL4(DBD):EcR(LBD) fusion proteins can bind to GAL4 response elements in the absence of ligand. The VP16(AD) fusion protein of a chimera between human and locust RXR could heterodimerize with GAL4(DBD):EcR(LBD) in the absence of ligand but the VP16(AD) fusion protein of Homo sapiens RXR requires ligand for its heterodimerization with GAL4(DBD):EcR(LBD).     

Synthesis, antioxidant and toxicological study of novel pyrimido quinoline derivatives from 4-hydroxy-3-acyl quinolin-2-one

A series of novel pyrimido and other fused quinoline derivatives like 4-methyl pyrimido [5,4-c]quinoline-2,5(1H,6H)-dione (4a), 4-methyl-2-thioxo-1,2-dihydropyrimido [5,4-c]quinoline-5(6H)-one (4b), 2-amino-4-methyl-1,2-dihydropyrimido [5,4-c]quinolin-5(6H)-one (4c), 3-methylisoxazolo [4,5-c]quinolin-4(5H)-one (4d), 3-methyl-1H-pyrazolo [4,3-c]quinoline-4(5H)-one (5e), 5-methyl-1H-[1,2,4] triazepino [6,5-c]quinoline-2,6(3H,7H)-dione (5f), 5-methyl-2-thioxo-2,3-dihydro-1H-[1,2,4]triazepino [6,5-c]quinolin-6(7H)-one (5 g) were synthesized regioselectively from 4-hydroxy-3-acyl quinolin-2-one 3. They were screened for their in vitro antioxidant activities against radical scavenging capacity using DPPH(), Trolox equivalent antioxidant capacity (TEAC), total antioxidant activity by FRAP, superoxide radical (O(2)(°-)) scavenging activity, metal chelating activity and nitric oxide scavenging activity. Among the compounds screened, 4c and 5 g exhibited significant antioxidant activities.     

Analysis of Genetic Diversity in the North Eastern Himalayan Maize Landraces using Microsatellite Markers

Population DNA fingerprinting of 48 selected North Eastern Himalayan (NEH) landrace accessions was undertaken using 41 polymorphic fluorescent dye-labelled microsatellite/Simple Sequence Repeat (SSR) markers, using a DNA Sequencer. The analysis revealed a large number of SSR alleles (576), with high mean number of alleles per locus (13.8), and Polymorphism Information Content (PIC) of 0.63, reflecting the level of diversity in the NEH accessions and the informativeness of the SSR markers. The study also led to identification of 135 unique alleles, differentiating 44 out of the 48 accessions. Five highly frequent (major) SSR alleles (umc1545 _80bp, phi062 _162bp, umc1367 _159bp, umc2250 _152bp and phi112 _152bp) were detected indicating that chromosomal regions harbouring these S SR alleles might not be selectively neutral. Analysis of population genetic parameters, including Wright’s F statistics, revealed high level of genetic differentiation, very low levels of inbreeding, and restricted gene flow between the NEH landraces. AMOVA (Analysis of Molecular Variance) showed that 67 per cent of the total variation in the accessions could be attributed to within-population diversity, and the rest between the accessions. Cluster analysis of SSR data using Rogers’ genetic distance and UPGMA, showed significant genetic diversity among the landraces from Sikkim. This is the first detailed study of SSR allele frequency-based analysis of genetic diversity in the NEH maize landraces of India.     

Estimation of distribution function in bivariate competing risk models

We consider lifetime data involving pairs of study individuals with more than one possible cause of failure for each individual. Non-parametric estimation of cause-specific distribution functions is considered under independent censoring. Properties of the estimators are discussed and an illustration of their application is given.     

Changes of soluble proteins in leaf and thylakoid exposed in high saline condition of a mangrove taxa Bruguiera gymnorrhiza

One-year-old seedlings of Bruguiera gymnorrhiza (L) Savingay were exposed to 500 mM NaCl for 6d under hydroponic culture condition to characterize the changes in leaf and thylakoid protein profiles in response to short-term salt exposures. Significant changes in leaf dry mass, chlorophylls and soluble leaf proteins were observed in short term of salt exposures, as it happens under tidal situations in nature. Chlorophyll a/b ratio showed decrease of light harvesting efficiency in salt treatment. Total soluble proteins in leaves were extracted from control and NaCl-treated plants at 2d intervals and were analyzed by SDS-PAGE. Intensity of several protein bands of different molecular mass of leaf protein profile ranging from 10 to 86 kDa (10, 16, 23, 33, 37, 42, 44, 50 and 86 kDa) were decreased due to high salt treatment. Out of these, 16, 23 and 33 kDa protein bands decreased dramatically from 1–3 fold but recovered in 7d growth, except the 33 kDa band. SDSPAGE profile of thylakoid protein revealed that both number and the intensity of several protein bands got altered by salt concentration. However, 33 kDa protein band of thylakoid reappeared in recovery that might not be of the same characteristics with same molecular mass as shown in total leaf protein profile. The numbers of major bands found in SDS-PAGE were reduced when analyzed in urea-SDS-PAGE to minimize protein aggregations by high salt. It was noted that 47 kDa disappeared while some proteins of apparent molecular mass like 23 kDa, 33 kDa, 37 kDa and 50 kDa degraded to minor bands. Partial restoration of protein bands occurred when the salt-treated plants were brought back to initial growth condition. These results clearly demonstrate that short term high salt concentration could cause major alterations to photosynthetic apparatus of a true non salt-secreting tree mangrove Bruguiera gymnorrhiza and adapted against fluctuation of salinity by altering leaf protein pool relatively more than the thylakoid proteins.Key words: Bruguiera gymnorrhiza, Mangrove, Polypeptides, Salt shock, Sodium chloride, Thylakoid     

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

This investigation was undertaken to characterize the abundance and genera-wise diversity of cyanobacteria in the rice rhizosphere and nitrogen-fixing ability of the isolated strains. The cyanobacterial strains belonging to the genera Nostoc and Anabaena comprised 80% of the rhizosphere isolates, which were also efficient in enhancing the germination and growth of wheat seeds and exhibited significantly high protein accumulation and IAA production. Distinct profiles for the cyanobacterial strains were obtained on amplification with extended Hip 1 primer — HipTG, indicative of the diversity among these strains. Our investigation helped in identifying promising cyanobacterial isolates from the rhizosphere of rice, which can be utilized in developing efficient plant growth promoting cyanobacterial inoculants.     

Deglycosylated milin unfolds via inactive monomeric intermediates

The effect of deglycosylation on the physiological and functional organization of milin was studied under different denaturizing conditions. Trifluoromethanesulfonic acid mediated deglycosylation resulted in insoluble milin, which was found to be soluble only in 1.5 M GuHCl with native-like folded structure. Kinetic stability, proteolytic activity, and dimeric association were lost in deglycosylated milin. Urea-induced unfolding revealed two inactive, highly stable equilibrium intermediates at pH 7.0 and pH 2.0. These intermediates were stable between 5.5–6.5 and 5.0–6.0 M total chaotropes (urea + 1.5 M GuHCl) at pH 7.0 and pH 2.0, respectively. GuHCl-induced unfolding was cooperative and noncoincidental with a broad transition range (2.0–5.0 M) at pH 7.0 and pH 2.0. Equilibrium unfolding of deglycosylated milin by urea and GuHCl substantiates the involvement of various inactive monomeric intermediates. This study provides a way to understand the role of glycosylation in the unfolding mechanism, stability, and functional activity of the serine protease milin.     

A Fragrant Solution to Soil Remediation

The ability of scented geraniums (Pelargonium sp. ‘Frensham’) plants to tolerate, uptake, and accumulate lead was assessed compared with two well-established metal accumulators, Indian mustard (Brassica juncea) and sunflower (Helianthus annuus), under greenhouse conditions. The efficiency of the photosynthetic apparatus and the number and size of active photosynthetic reaction centers (expressed as chlorophyll a fluorescence ratios of variable fluorescence to maximal fluorescence [Fv/Fm] and variable fluorescence to unquenchable portion of fluorescence [Fv/Fo], respectively) were affected to varying degrees at all metal concentrations in all the plants tested. Lead exposure did not significantly affect the efficiency of photosystem II activity or the number and size of the photosynthetic reaction centers in scented geraniums, but the ratios decreased significantly in Indian mustard and sunflower plants following lead exposure. In addition to tolerating high levels of lead, the scented geraniums accumulated in excess of 3000 mg of lead per kg DW of shoot and above 60,000 mg of lead per kg DW of root tissue. Additionally, scented geraniums exposed to a mixture of metals (lead + cadmium + nickel) had the ability to uptake in excess of 4.72% Pb + 0.44% Cd + 0.52% Ni per kg of root DW, as well as 0.17% Pb + 0.07% Cd + 0.14% Ni per kg of shoot DW within 14 d, indicated the potential for existence of more than one functional tolerance and metal uptake mechanism(s). The cellular localization of lead was assessed using transmission electron microscopy coupled with an X-ray microanalyzer. Lead accumulation was observed in the apoplasm and in the cytoplasm, vacuoles, and as distinct globules (potentially as lead-lignin or lead-phosphate complexes) on the cell membrane and cell wall. We conclude that the ability of scented geraniums to tolerate high lead accumulation in its biomass is due, in part, to limiting damage to photosynthetic apparatus and metal detoxification by formation of metal complexes.     

Identification and Characterization of a New Lipoprotein, NlpI, in Escherichia coli K-12

We report here the identification of a new lipoprotein, NlpI, in Escherichia coli K-12. The NlpI structural gene (nlpI) is located between the genes pnp (polynucleotide phosphorylase) and deaD (RNA helicase) at 71 min on the E. coli chromosome. The nlpI gene encodes a putative polypeptide of approximately 34 kDa, and multiple lines of evidence clearly demonstrate that NlpI is indeed a lipoprotein. An nlpI::cm mutation rendered growth of the cells osmotically sensitive, and incubation of the insertion mutant at an elevated temperature resulted in the formation of filaments. The altered phenotype of the mutant was a direct consequence of the mutation in nlpI, since it was complemented by the wild-type nlpI gene alone. Overexpression of the unaltered nlpI gene in wild-type cells resulted in the loss of the rod morphology and the formation of single prolate ellipsoids and pairs of prolate ellipsoids joined by partial constrictions. NlpI may be important for an as-yet-undefined step in the overall process of cell division.