Atmospheric concentration of pollen grains at human height

An atmospheric survey at human height (1.5–1.8 ft) was carried out from February 1988 to January 1990, in four different ecozones of the Delhi metropolis. The samples were collected by using Burkard Personal Volumetric Sampler at weekly intervals. The sampler was operating for 15 min three times a day (07, 14, 20 hrs). Altogether, 84 pollen types were identified. Some of the dominant pollen types recorded were Poaceae (25.1%), Cheno/Amaranthaceae (14.5%) and Ricinus communis (12.3%) followed by Morus, Cannabis, Prosopis, Parthenium and Artemisia. Weekly variations were recorded for the total number of pollen of different types in different months. Two major pollen seasons 1. February — April and 2. August — October were observed, although pollen was recorded throughout the year. Significant variation in total and individual pollen concentration was recorded from different inhabited areas in the same urban locality. Any definite daily pattern in the occurrence of pollen was not recorded. The concentration at lower height was also poor.     

QTL Mapping of Agronomic Waterlogging Tolerance Using Recombinant Inbred Lines Derived from Tropical Maize (Zea mays L) Germplasm

Waterlogging is an important abiotic stress constraint that causes significant yield losses in maize grown throughout south and south-east Asia due to erratic rainfall patterns. The most economic option to offset the damage caused by waterlogging is to genetically incorporate tolerance in cultivars that are grown widely in the target agro-ecologies. We assessed the genetic variation in a population of recombinant inbred lines (RILs) derived from crossing a waterlogging tolerant line (CAWL-46-3-1) to an elite but sensitive line (CML311-2-1-3) and observed significant range of variation for grain yield (GY) under waterlogging stress along with a number of other secondary traits such as brace roots (BR), chlorophyll content (SPAD), % stem and root lodging (S&RL) among the RILs. Significant positive correlation of GY with BR and SPAD and negative correlation with S&RL indicated the potential use of these secondary traits in selection indices under waterlogged conditions. RILs were genotyped with 331 polymorphic single nucleotide polymorphism (SNP) markers using KASP (Kompetitive Allele Specific PCR) Platform. QTL mapping revealed five QTL on chromosomes 1, 3, 5, 7 and 10, which together explained approximately 30% of phenotypic variance for GY based on evaluation of RIL families under waterlogged conditions, with effects ranging from 520 to 640 kg/ha for individual genomic regions. 13 QTL were identified for various secondary traits associated with waterlogging tolerance, each individually explaining from 3 to 14% of phenotypic variance. Of the 22 candidate genes with known functional domains identified within the physical intervals delimited by the flanking markers of the QTL influencing GY and other secondary traits, six have previously been demonstrated to be associated with anaerobic responses in either maize or other model species. A pair of flanking SNP markers has been identified for each of the QTL and high throughput marker assays were developed to facilitate rapid introgression of waterlogging tolerance in tropical maize breeding programs.     

Development of co-dominant KASP markers co-segregating with Ug99 effective stem rust resistance gene <Emphasis Type="Italic">Sr26</Emphasis> in wheat

Stem rust of wheat, caused by Puccinia graminis f. sp. tritici (Pgt), is a threat to global food security due to its ability to cause total crop failures. The Pgt race TTKSK (Ug99) and its derivatives detected in East Africa carry virulence for many resistance genes present in modern cultivars. However, stem rust resistance gene Sr26 remains effective to all races of Pgt worldwide. Sr26 is carried on the Agropyron elongatum (syn. Thinopyrum ponticum) segment 6Ae#1L translocated to chromosome 6AL of wheat. In this study, a recombinant inbred line (RIL) population derived from a cross between the landrace Aus27969 and Avocet S, which carries Sr26, was used to develop co-dominant kompetitive allele-specific polymerase chain reaction (KASP) markers that co-segregate with Sr26. Four KASP markers (sunKASP_216, sunKASP_218, sunKASP_224 and sunKASP_225) were also shown to co-segregate with Sr26 in four additional RIL populations. When tested on Australian cultivars and breeding lines, these markers amplified alleles alternate to that linked with Sr26 in all cultivars known to lack this gene and Sr26-linked alleles in cultivars and genotypes known to carry Sr26. Genotypes WA-1 and WA-1/3*Yitpi carrying the shortest Sr26 translocation segment were positive only for markers sunKASP_224 and sunKASP_225. Our results suggest the four KASP markers are located on the original translocation and sunKASP_224 and sunKASP_225 are located on the shortened version. Therefore, sunKASP_224 and sunKASP_225 can be used for marker-assisted pyramiding of Sr26 with other stem rust resistance genes to achieve durable resistance in wheat.     

Discovery of 3(S)-thiomethyl pyrrolidine ERK inhibitors for oncology

Compound 5 (SCH772984) was identified as a potent inhibitor of ERK1/2 with excellent selectivity against a panel of kinases (0/231 kinases tested @ 100?nM) and good cell proliferation activity, but suffered from poor PK (rat AUC PK @10?mpk?=?0?μM?h; F%?=?0) which precluded further development. In an effort to identify novel ERK inhibitors with improved PK properties with respect to 5, a systematic exploration of sterics and composition at the 3-position of the pyrrolidine led to the discovery of a novel 3(S)-thiomethyl pyrrolidine analog 28 with vastly improved PK (rat AUC PK @10?mpk?=?26?μM?h; F%?=?70).     

Synthesis and biological evaluation of longanlactone analogues as neurotrophic agents

Longanlactone analogues were synthesized using a route featuring Friedel-Crafts acylation, Sonogashira coupling and 1,3-dipolar cycloaddition reactions. Structure–activity relationships were investigated for neurotrophic activity. Compound 6 was found to have the most potent neurotrophic activity among all the synthesized analogues in Neuro2a cells as evidenced by a battery of in vitro/cell based assays for assessment of neurogenic and potential neurotrophic activity including neurite outgrowth assay and real time PCR for popular markers of augmented neurotrophic activity. Compound 6 might serve as a template for further development of highly effective neurotrophic molecules.     

The structure of DLP12 endolysin exhibiting alternate loop conformation and comparative analysis with other endolysins

The lytic enzyme, endolysin, is encoded by bacteriophages (phages) to destroy the peptidoglycan layer of host bacterial cells. The release of phage progenies to start the new infection cycle is dependent on the cell lysis event. Endolysin encoded by DLP12 cryptic prophage is a SAR endolysin which is retained by the bacterium presumably due to the benefit it confers. The structure of DLP12 endolysin (Id: 4ZPU) determined at 2.4 Å resolution is presented here. The DLP12 endolysin structure shows a modular nature and is organized into distinct structural regions. One of the monomers has the loops at the active site in a different conformation. This has led to a suggestion of depicting possibly active and inactive state of DLP12 endolysin. Comparison of DLP12 endolysin structure and sequence with those of related endolysins shows the core three‐dimensional fold is similar and the catalytic triad geometry is highly conserved despite the sequence differences. Features essential for T4 lysozyme structure and function such as the distance between catalytic groups, salt bridge and presence of nucleophilic water are conserved in DLP12 endolysin and other endolysins analyzed.     

Plant Responses to High CO2 Concentration in the Atmosphere

The impact of continuous rise in ambient CO₂ concentration (AC) in the atmosphere on different facets of growth of crop plants is assessed. The effects of CO₂ enrichment (EC) on plant growth, C₃ and C₄ photosynthesis, source-sink ratio, partitioning and translocation of metabolites, photosynthetic enzymes, respiratory rate, leaf area index, stomatal conductance (q _s ), transpiration rate, biomass production and water use efficiency are reviewed. The CO₂ fertilization effects are studied in both short-term (open top chambers) and long-term experiments. Long-term experiments suggest that ribulose-1,5-bisphosphate carboxylase is inactivated at high CO₂ concentrations. Also g _s is lowered. One of the conspicuous effects of EC is the closure of stomata in C₃ plants. Photosystem (PS) 2 electron transport is more affected than PS1. Starch is the immediate product accumulated in the leaf of C₃ plants. The “CO₂ fertilization effect” does not confer any great advantage even in C₃ plants. This revised version was published online in September 2006 with corrections to the Cover Date.     

Identification and validation of genomic regions influencing kernel zinc and iron in maize

Key message

Genome-wide association study (GWAS) on 923 maize lines and validation in bi-parental populations identified significant genomic regions for kernel-Zinc and-Iron in maize.

Abstract

Bio-fortification of maize with elevated Zinc (Zn) and Iron (Fe) holds considerable promise for alleviating under-nutrition among the world’s poor. Bio-fortification through molecular breeding could be an economical strategy for developing nutritious maize, and hence in this study, we adopted GWAS to identify markers associated with high kernel-Zn and Fe in maize and subsequently validated marker-trait associations in independent bi-parental populations. For GWAS, we evaluated a diverse maize association mapping panel of 923 inbred lines across three environments and detected trait associations using high-density Single nucleotide polymorphism (SNPs) obtained through genotyping-by-sequencing. Phenotyping trials of the GWAS panel showed high heritability and moderate correlation between kernel-Zn and Fe concentrations. GWAS revealed a total of 46 SNPs (Zn-20 and Fe-26) significantly associated (P?≤?5.03?×?10^?05) with kernel-Zn and Fe concentrations with some of these associated SNPs located within previously reported QTL intervals for these traits. Three double-haploid (DH) populations were developed using lines identified from the panel that were contrasting for these micronutrients. The DH populations were phenotyped at two environments and were used for validating significant SNPs (P?≤?1?×?10^?03) based on single marker QTL analysis. Based on this analysis, 11 (Zn) and 11 (Fe) SNPs were found to have significant effect on the trait variance (P?≤?0.01, R²?≥?0.05) in at least one bi-parental population. These findings are being pursued in the kernel-Zn and Fe breeding program, and could hold great value in functional analysis and possible cloning of high-value genes for these traits in maize.