Analysis of Two Maize Mutations that Arose After Exposure to Radiation from a Plutonium-Beryllium Source and Developing Molecular Markers for Antimorph AEI1-5180, An Alternative to AEI to Increase Amylose Content in Maize Endosperm

This thesis consists of two independent projects dealing with two different aspects of maize. The first project is about the maize reproduction, where we try to uncover the candidate genes of two mutations that affect pollen viability and successful fertilization. The second project is about maize endosperm starch, where we developed molecular markers to characterize a mutant allele that knocks a major starch branching enzyme in maize. Analysis of two maize mutations that arose after exposure to radiation from a plutonium-beryllium source Maize is a monoecious and diclinous plant. Sexual reproduction takes place by the fusion of haploid male and female gametes produced in the anther and ovule, respectively. The male gametophyte is pollen, a trinucleate structure, that consists of two sperm cells and a vegetative cell. The female gametophyte is embryo sac, that consists of an egg cell, two synergids, two central cells and a variable number of antipodal cells. After pollination, the vegetative cell germinates and forms a pollen tube. The pollen tube elongates through the style, penetrates the ovule, and finally burst after reaching embryo sac to release two sperm cells. One sperm cell fuse with the haploid egg cell in embryo sac and forms a diploid embryo, whereas the other fuses with two central cells to form a triploid endosperm. In the first project, we developed two mutant lines, PB1 and PB2 by exposing kernels heterozygous for r1 (colored 1) and c1 (colored-aleurone 1) color factors to a fast neutron source for three and six months, respectively. Two mutagenized plants when crossed with r1 and c1 testers, showed reduced transmission for the R1 marker through pollen, but normal transmission through female. Instead of 50%, the R1 transmission rate through pollen was 23.6% ±0.61% (mean ±se) for PB1, and 1.48% ±0.44% (mean ±se) for PB2. Comparison of whole genome sequences of PB1, PB2 and the unmutated parental line PB1, shows that 32 genes are affected by the deletions in PB1, whereas in PB2, 45 genes are affected. In PB2, genes that code for mechanosensitive ion channel protein, C2H2 type Zinc finger family protein and β-expansin have been previously reported to affect pollen tube germination and elongation, which makes them good candidates. Developing molecular markers for antimorph Ae1-5180, an alternative to ae1 to increase amylose content in maize endospermMaize endosperm consists of mostly starch, which is made of unbranched amylose and branched amylopectin residues. In most Midwestern dents, the endosperm starch is about 75% amylopectin and 25% amylose. Branch formation is catalyzed by starch branching enzymes. Starch branching enzyme IIB (SBEIIb) encoded by ae1 (amylose extender 1), is the primary starch branching enzyme that forms amylopectin. The amylose content increases up to 50% when ae1 is homozygous recessive. An antimorph allele (Ae1-5180), was identified that acts in a dominant fashion to eliminate SBEIIb (Stinard et al., 1993). The essential portion of this mutant allele is a 3kb XhoI fragment that includes Mutator1 (Mu1) element flanked by an inverted duplication of the ae1 gene. Based on the restriction map (Stinard et al., 1993) we developed an approximate predicted sequence for Ae1-5180 using the known sequences of the wildtype ae1 gene and Mu1 transposon. Using this, we designed PCR primers targeted to amplify regions within a 3 kb XhoI restriction fragment that appears crucial for the dominant action of Ae1-5180. The primers amplify two DNA bands from samples expected to have Ae1-5180, but none from B73. The sequence of the lower molecular weight band matches with 181 bp of Mu1 and 364 bp of Ae1 (545 bp). The higher molecular weight band also possesses 181 bp of Mu1 but includes 438 bp of Ae1 (619 bp). The additional 74 bp includes a restriction site for NotI, which was predicted from the original restriction map. Sequencing results indicate that these primers reliably detect the presence or absence of the Ae1-5180 allele. Also, the insertion site of Mu1 in Ae1-5180 is now exactly defined

Quantitative Trait Loci Analysis of Low Temperature Responses in Grapevine F2 Population

Freezing injury, caused by freezing temperatures in the late fall, midwinter, or early spring, can result in significant loss to grape growers. The damage may range from the partial damage of parts of the plants to the total death of the plant, and may vary between years. Freezing tolerance is a multi-genetic, complex quantitative trait that involves many related traits like dormancy induction, growth cessation, acclimation, deacclimation and bud break. Developing an understanding of the genetics behind the complex trait requires connecting the phenotype with the genotype to enable discovering the underlying genes that can contribute to quantifiable differences between individuals. The objective of this thesis is to detect the genomic location(s) underlying genetic variation in low-temperature response traits like freezing tolerance and bud break using quantitative trait loci analysis (QTL). An F2 population developed by selfing a single F1 from a cross between American species Vitis riparia and a hybrid grapevine Seyval, was used to conduct QTL analysis for subzero temperature tolerance. The low temperature exotherms (LTE) obtained from differential thermal analysis (DTA) were used as phenotype data for the QTL analysis. The phenotyping was conducted in multiple months and dormant seasons. LTE results when the supercooled water inside the bud freezes and identifies the temperature at which buds are killed. Best linear unbiased predictors (BLUP) was also calculated using the LTEs to calculate random genetic effects. Composite interval mapping (CIM) was conducted using either the average LTEs or BLUP values in R/QTL with 1000 permutations and error rate of 5%. The LTEs for individual genotypes varied in the different months. QTLs were identified using either average LTEs or BLUP values for all the months and dormant seasons. QTLs appeared on Chromosome 1, 5, 9, 13 and 16 in different months or dormant seasons. Many potential candidate genes associated with calcium signaling, ethylene signaling, ABA signaling, cellular metabolism and dehydration response were found underlying the 1.5 LOD interval of these QTLs. The bud break phenology was studied at three chilling periods to identify bud break related QTL. Bud break occurs upon the exposure to optimal growth conditions, after the chilling requirement fulfillment transitions the bud from endodormancy to ecodormancy. Three one node cuttings of the grapevines were forced at 13 hours of daylength and 25⁰C/20⁰C thermoperiod in the growth chamber for four weeks. Each week the growth stage of the cuttings was scored using Modified Eichhorn-Lorenz (Modified E-L) phenology scale. This was repeated in multiple dormant seasons and months. The bud break data was ordinal, monotonic and based on repeated measurements, thus similar to data in disease epidemiological studies in which disease severity is scored repeatedly over a time period. Therefore, the concept of area under the curve (AUC) was applied to the bud break data. The area under the bud break progression curve (AUBPC) was calculated for the bud break data of each individual for an individual month. CIM was conducted with the average week 3 phenology score data or AUBPC data in R/qtl using 1000 permutations. Both data processing approaches provided similar QTL results on chromosome 3, 7, 8, 9, 13, 18 and 19. These QTLs encompassed candidate genes involved in calcium signaling, auxin signaling, ethylene signaling, circadian clock signaling, cellular metabolism, primary and secondary metabolism, dehydration stress response, drought stress response, fruit ripening and many transcription factors. The results from this study can be useful in developing low temperature response trait markers that can be applied in marker-assisted breeding and selection to develop the grapevine cultivars suitable for northern continental climates where freezing temperatures are common. This will enhance the sustainability of cold climate grape production and promote expansion of grape growing regions

Connectivity Investigation of Channel Quality-Based Adaptive Gossip Flooding Mechanism for AODV

To address the “broadcast storm” problem associated with flooding-based route discovery mechanism of reactive routing protocols, probabilistic approaches are suggested in the literature. In the earlier work, Gossip flooding mechanism of Haas et.al. was extended with signal quality, to propose channel quality based adaptive gossip flooding mechanism for AODV (CQAG-AODV). Following the cross-layer design principle, CQAG-AODV algorithm tried to discover robust routes, as well as address the “broadcast storm” problem by controlling the rebroadcast probability of Route request (RREQ) packets on the basis of signal strength experienced at the physical layer. This paper investigates the connectivity of CQAG-AODV through theoretical and simulation analysis. Results show that, by accounting the signal strength in the route discovery process, not only does the proposed algorithm floods  a lesser number of route requests and controls the broadcast storm, but also maintains a higher level of connectivity to offer high packet delivery ratio; independent of network density and node mobility. Moreover, due to controlled routing overhead and robust route discovery, channel quality based adaptive flooding mechanism offers fringe benefit of energy efficiency as well. CQAG-AODV thus proves its suitability in a variety of use cases of multi-hop ad hoc networks including WSNs and VANETs

STRUCTURAL AND OPTICAL INVESTIGATION OF PURE AND LANTHANUM DOPED ZnO NANOPARTICLES SYNTHESIZED BY CO-PRECIPITATION METHOD

Objective: Zinc oxide nanoparticles are assumed to be the foundation for several applications including environmental applications, optical devices, telecommunication, energy storage and so on. Its very crucial to obtain uniform and good quality nanoparticles in their properties point of view. Materials and Methods: Pure and rare earth material (La) doped ZnO nanoparticles were prepared by co-precipitation route with heating temperature of 200oC and their properties were comparatively studied in this work. The structural properties were carried out by X-Ray diffraction technique and Optical analysis was done by using UV-Vis spectrophotometer. Results: Structural investigations show that all the crystallites are of hexagonal wurtzite structure with preferred orientation along (101) plane. Further, optical analysis indicates that the average transmittance of the prepared samples is 85 % in visible region of spectrum. Moreover, Energy band gap studies reveal the increase in energy band gap from 3.23eV to 3.24 eV with incorporation of La+3 in ZnO lattice. Conclusion: These analyses indicate that doping Zinc oxide with lanthanum varies and enhances the properties of prepared thin films

DBLP-QuAD: A Question Answering Dataset over the DBLP Scholarly Knowledge Graph

In this work we create a question answering dataset over the DBLP scholarly knowledge graph (KG). DBLP is an on-line reference for bibliographic information on major computer science publications that indexes over 4.4 million publications published by more than 2.2 million authors. Our dataset consists of 10,000 question answer pairs with the corresponding SPARQL queries which can be executed over the DBLP KG to fetch the correct answer. DBLP-QuAD is the largest scholarly question answering dataset.Comment: 12 pages ceur-ws 1 column accepted at International Bibliometric Information Retrieval Workshp @ ECIR 202

Histopathological examination of emergency obstetric hysterectomy specimens

Background: Obstetric hysterectomy is done as a lifesaving procedure in very trying circumstances of life threatening severe hemorrhage. The study was undertaken with the aim to evaluate the relative frequency of hysterectomy done for obstetric indication among the hysterectomy specimens and also to assess the histopathological findings in the hysterectomy specimens.Methods: The study was conducted at a tertiary care center over a period of two and half years. Consecutive specimens of hysterectomy done for obstetrical indication were included. Gross and microscopic findings noted and data analysed. The study was approved by the Institute Ethical Committee.Results: Of the total hysterectomy specimens received obstetrical hysterectomy comprised only 1.3%(12/915) of all the hysterectomies. Patient’s age ranged from 20-36 years; mean 28.6 years. Parity ranged from 1 to 5; mean 2. More multiparous women 91.7%(11/12) had hysterectomies as compared to primiparous 8.3%(1/12) cases                         (p value <0.0001). All patients had single pregnancy. All (100%) patients underwent surgery through abdominal route with subtotal hysterectomy with preservation of the bilateral adnexae undertaken in most (11/12; 91.7% cases). About 5(41.6%) cases hysterectomies were performed after previous caesarean section and had abnormal placentation. Histopathological examination revealed adherent placenta in 33.4%(4/12), endometritis in 25%(3/12), rupture in 25%(3/12) and histologically unremarkable in 16.6%(2/12) cases.Conclusions: Obstetric hysterectomy is an emergency lifesaving procedure done in situations of uncontrolled post-partum hemorrhage. In recent years with more number of caesarean sections the incidence of abnormal placentation has drastically increased, thus making adherent placenta as the most common histopathological finding