Molecular mechanisms regulating early cone development in Norway spruce Picea abies (Karst)

Flower development progress through distinct phases that are controlled by complex genetic networks, which in turn are regulated by both endogenous and exogenous factors. A large number of functional studies have been conducted over the past decades to understand the genetic networks that regulate flower development in angiosperm model species. In gymnosperms, however, the gene regulatory networks behind distinct phases of cone development are largely unknown due to the lack of functional studies. In a morphological study of early cone development in Picea abies, three distinct growth phases were defined. Transcriptome comparisons of female and vegetative buds in the three growth phases identified members of the MADS-box gene family, LEAFY-orthologs, bZIP- , AP2-, and SBP-domain proteins as being highly expressed in the different phases of female cone development. In a separate study different isoform of the MADS-box gene, DAL19 were identified. Isoforms specific expression in male, female and vegetative bud meristems provided evidence that alternative splicing may influence cone formation in a bud identity specific manner. In the early cone-setting acrocona mutant, P. abies var. acrocona, leading shoots often have needles at the base, but ovuliferous scale-like structures in the top. Hence, during shoot development, the leading shoots make a morphological shift and produce transition shoots. RNA sequencing of acrocona transition shoots demonstrated that the MADS-box genes DAL10 and DAL21, which previously have been associated with reproductive shoot identity were expressed at high levels in transition shoot meristems before the morphological shift. In addition, genes encoding FT/TFL-like, bZIP-, SOC1-like and gymnosperm specific MADS-domain proteins co-expressed with DAL10 and DAL21, suggesting at a putative role for these genes in the early development of reproductive meristems. In addition, genes encoding F-box protein and ubiquitin were expressed at high levels in late acrocona transition shoots, which possibly reflects an involvement of hormonal signalling in the acrocona transition shoot phenotype

Chemical, biochemical, and cellular aspects of S-nitrosothiols.

Nitric oxide is involved in many physiological processes including vascular control, immune responses and neurotransmission under physiological conditions. Many functions of NO are triggered by the formation of its metabolite, S-nitrosothiol. S-nitrosothiols play an important role in the delivery, storage and transport of NO. In addition, they regulate the activity of a variety of proteins and enzymes. The first part of my study is focused on studying the regulatory role of S-nitrosothiol. In this study, S-nitrosothiols including S-nitrosoglutathione (GSNO) have been demonstrated to regulate the activity of a key protein in plasma, fibrinogen, without chemically modifying it. GSNO and a few other RSNO derivatives have demonstrated the ability to inhibit thrombin catalyzed fibrinogen polymerization via their effects on fibrinogen, whereas the activity of thrombin itself remained intact upon incubation with GSNO. The percentage of inhibition obtained ranged from 43% to 68%. Upon incubation with GSNO, the alpha-helix content of fibrinogen increased by 15%. The GSNO fibrinogen interaction was allosteric and reversible with an estimated dissociation constant of 3-10 muM. Fibrinogen has been demonstrated to contain 2 binding sites for GSNO. The second part of my study deals with the chemical and cellular aspects of S-nitrosothiols. I formed a coloured nitrite adduct of sinapinic acid (SA) which has shown the ability to S-nitrosate thiol-containing amino acids and proteins. In addition, this nitrite adduct has demonstrated the potential for spectrophotometric detection of NO derived species, NO+ or peroxynitrite in vitro or under physiological conditions. In addition, I synthesized an S-nitroso derivative of 1-octadecane thiol, S-nitrosooctadecane (SNOD). We also designed SNOD-BSA nanoparticles, which were capable of delivering large amounts of SNOD to human fibroblasts. In preliminary studies, the illumination of SNOD-BSA loaded fibroblasts induced apoptosis in 58% of the fibroblasts. The third part of my study deals with the molecular aspects of S-nitrosothiols. Under physiological conditions, the reaction between NO and O2 •- produces peroxynitrite. I have shown previously that upon exposure to light, an air-saturated GSNO solution can also give rise to peroxynitrite. Peroxynitrite causes inactivation of many proteins and enzymes by nitrating their tyrosine residues. We created three different tyrosine mutants of rat calmodulin namely, CaM Y99A CaM Y138A, and CaM Y99AY138A for assessing the roles of its two tyrosine residues. Mutations of the tyrosine residues apparently affected calmodulin\u27s stability and its Ca2+ binding ability. S-nitrosothiols are also capable of causing DNA damage. For the purpose of decontaminating platelet-rich plasma, we synthesized two fluorophore labelled S-nitrosthiols namely N-dansyl-S-nitrosohomocysteine (Dns-HCysNO) and N-dansyl-S-nitrosoglutathione (Dns-GSNO), which could mediate the cleavage of DNA upon exposure to light. Dns-HcysNO solutions degraded R773 plasmid DNA completely upon exposure to light and the extent of degradation was a function of exposure time. In contrast, only a high concentration of Dns-HCysNO degraded plasmid DNA partially without exposure to light. Thus, Dns-HCysNO could be potentially utilized for light-induced DNA cleavage in order to decontaminate platelet rich plasma.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .A44. Source: Dissertation Abstracts International, Volume: 64-08, Section: B, page: 3800. Adviser: Bulent Mutus. Thesis (Ph.D.)--University of Windsor (Canada), 2003

Interactions between Rhizobium, antagonistic bacteria and fungal pathogens in faba bean

Plant associated micro-organisms such as nitrogen-fixing Rhizobium, and plant growth- promoting rhizobacteria (PGPR) Pseudomonas spp. and Serratia spp. are well recognised for their vital role in soil fertility and plant health. Most cultivated soils contain large populations of such micro-organisms. A diversity of interactions occur between rhizobia and PGPR with leguminous plants in natural conditions, however, their associations and functions in field crops such as faba bean is less studied. In Sweden, faba bean cultivation is increasing because of increasing demand for self-sufficiency of native protein feed. Two of the most serious diseases to limit the yield of faba beans are chocolate spot disease and Ascochyta blight. This thesis contains several studies. One study was done on the microbial communities naturally associated with faba bean seeds of two different cultivars. In another study, the role of selected bacteria for health of faba bean was examined. Furthermore, the antagonistic ability of Rhizobium and PGPR towards faba bean pathogens, and the compatibility and root colonization competence of the two beneficial bacteria was investigated. Cultivation-dependent and cultivation-independent approaches used to study the seed microbial community structure revealed high diversity, which seemed to be affected by the health status of the seeds. Enterobacteriaceae dominated the bacterial flora and Serratia, Pseudomonas and Burkholderia were among the numerous genera that inhabited the seeds. Higher bacterial growth in cv. Aurora seed exudates compared to cv. Fuego suggested differences in the chemical composition between the two varieties. Both rhizobial and PGPR isolates were shown to be antagonistic but PGPR proved to be stronger antagonists than rhizobia. Serratia proteamaculans S4 was strongest antagonist and produced both diffusible and volatilic antifungal metabolites. In greenhouse, rhizobia and PGPR colonised roots of both cultivars after single or co- inoculation but the level of colonisation differed depending on the cultivar and the isolate combination. Colonisation by Rhizobium leguminosarum was stimulated by fluorescent Pseudomonas sp. Positive effects of seed bacterisation with Rhizobium in greenhouse were evident in terms of emergence and plant growth in both Aurora and Fuego. The results presented here highlight the importance of multifarious interactions between bacteria, plant and pathogens for sustainability in crop production of faba bean

Being Cared for in the Context of Crisis: Austerity, COVID-19, and Racialized Politics

This article presents an investigation into the racialized and gendered dynamics of the intensifying crisis in care for older people in the United Kingdom. Deploying a feminist political economy framework, we reveal how the care crisis is an intersectional crisis of social reproduction worsened by both austerity and COVID-19. We do this through an analysis of a small set of interviews with South Asian older women with care needs, conducted during the first period of UK national lockdown in 2020. This was a pilot study, focusing on the challenges faced in accessing formal and informal care during this period of the pandemic. The experiences, fears, and vulnerabilities that came through in the interviews are located within a broader analysis of the racialized care crisis—one that reveals the long-term harms that austerity, including “austerity Islamophobia,” generated for these older women and their families as they struggled to provide and access un/paid care

Response of morphological and biochemical traits of maize genotypes under waterlogging stress

Maize (Zea mays L.) is one of the most important cereal crops cultivated around the world. Waterlogging stress is a major production constraint of maize production in rain-fed agricultural systems. The main objective of this experiment was to investigate the effect of continuous waterlogging on morphological and biochemical traits of maize genotypes at the vegetative stage. Ten maize genotypes were treated under no waterlogging (control) and continuous waterlogging of five centimeters depth for 10 days. The treatments were applied to the plants at their 45 days of age. Visual leaf injury scores from Leaf 4 (youngest leaf is the reference point) to Leaf 7 separated tolerant and susceptible genotypes. Waterlogging stress significantly reduced the total number of live leaves and chlorophyll content in leaf tissues in susceptible genotypes. The anatomical study revealed that tolerant maize genotypes produce a large number of aerenchyma cells under waterlogging stress compared to susceptible genotypes. The enzymatic activities of ascorbate peroxidase (APX) and peroxidase (POD) exhibited a greater increase in tolerant genotypes than susceptible genotypes whereas the contents of reactive oxygen species (H2O2) greatly increased in susceptible genotypes than tolerant genotypes under waterlogging stress compared to control. Principal component 2 (PC2) indicated that increasing plant height in the genotypes BHM-14, BHM-13 and BHM-9 was associated with waterlogging tolerance. The findings of this experiment will add value to maize breeding to screen out maize genotypes for waterlogging stress tolerance

Cone-setting in spruce is regulated by conserved elements of the age-dependent flowering pathway

Reproductive phase change is well characterized in angiosperm model species, but less studied in gymnosperms. We utilize the early cone-setting acrocona mutant to study reproductive phase change in the conifer Picea abies (Norway spruce), a gymnosperm. The acrocona mutant frequently initiates cone-like structures, called transition shoots, in positions where wild-type P. abies always produces vegetative shoots. We collect acrocona and wild-type samples, and RNA-sequence their messenger RNA (mRNA) and microRNA (miRNA) fractions. We establish gene expression patterns and then use allele-specific transcript assembly to identify mutations in acrocona. We genotype a segregating population of inbred acrocona trees. A member of the SQUAMOSA BINDING PROTEIN-LIKE (SPL) gene family, PaSPL1, is active in reproductive meristems, whereas two putative negative regulators of PaSPL1, miRNA156 and the conifer specific miRNA529, are upregulated in vegetative and transition shoot meristems. We identify a mutation in a putative miRNA156/529 binding site of the acrocona PaSPL1 allele and show that the mutation renders the acrocona allele tolerant to these miRNAs. We show co-segregation between the early cone-setting phenotype and trees homozygous for the acrocona mutation. In conclusion, we demonstrate evolutionary conservation of the age-dependent flowering pathway and involvement of this pathway in regulating reproductive phase change in the conifer P. abies

Addition of fructooligosaccharides and dried plum to soy-based diets reverses bone loss in the ovariectomized rat

Dietary bioactive components that play a role in improving skeletal health have received considerable attention in complementary and alternative medicine practices as a result of their increased efficacy to combat chronic diseases. The objectives of this study were to evaluate the additive or synergistic effects of dried plum and fructooligosaccharides (FOS) and to determine whether dried plum and FOS or their combination in a soy protein-based diet can restore bone mass in ovarian hormone deficient rats. For this purpose, 72 3-month-old female Sprague-Dawley rats were divided into six groups (n = 12) and either ovariectomized (Ovx, five groups) or sham-operated (sham, one group). The rats were maintained on a semipurified standard diet for 45 days after surgery to establish bone loss. Thereafter, the rats were placed on one of the following dietary treatments for 60 days: casein-based diet (Sham and Ovx), soy-based diet (Ovx + soy) or soy-based diet with dried plum (Ovx + soy + plum), FOS (Ovx + soy + FOS) and combination of dried plum and FOS (Ovx + soy + plum + FOS). Soy protein in combination with the test compounds significantly improved whole-body bone mineral density (BMD). All test compounds in combination with soy protein significantly increased femoral BMD but the combination of soy protein, dried plum and FOS had the most pronounced effect in increasing lumbar BMD. Similarly, all of the test compounds increased ultimate load, indicating improved biomechanical properties. The positive effects of these test compounds on bone may be due to their ability to modulate bone resorption and formation, as shown by suppressed urinary deoxypyridinoline excretion and enhanced alkaline phosphatase activity.Peer reviewedNutritional Science

Antinociceptive Activity of Methanol Extract of Areca catechu L. (Arecaceae) Stems and Leaves in Mice

ABSTRACT The antinociceptive effect of crude methanol extracts of stems and leaves of Areca catechu L. (Arecaceae) was evaluated in acetic acid-induced gastric pain writhing model in Swiss albino mice. The methanol extract of Areca catechu stems dose-dependently reduced the number of writhings (constrictions) in mice, when tested at doses of 50, 100, 200, and 400 mg extract administered per kg body weight. Significant reductions in the number of writhings were noted with all administered doses. The percent inhibitions of acetic acid-induced writhings with the four different doses were, respectively, 30.8, 36.6, 40.9 and 59.6. The standard antinociceptive drug, aspirin, when administered at doses of 200 and 400 mg per kg body weight reduced writhings by 42.3 and 55.8%, respectively. A significant dose-dependent inhibition of writhings was also observed with crude methanol extract of Areca catechu leaves, where the extract at doses of 50, 100, 200 and 400 mg per kg body weight significantly inhibited writhings by 55.8, 57.7, 86.5 and 88.5%, respectively. Dose for dose, the leaf extract demonstrated higher antinociceptive activity than the stem extract. At even the lowest dose of 50 mg extract per kg body weight, the antinociceptive activity of leaf extract was comparable to that of 400 mg aspirin per kg body weight. The results suggest that both stem and leaf extract possess good antinociceptive activity, which merits further scientific studies as to isolation of responsible phytochemical component(s)

Being cared for in the context of crisis : austerity, COVID-19 and racialized politics

This article presents an investigation into the racialized and gendered dynamics of the intensifying crisis in care for older people in the UK. Deploying a feminist political economy framework, we reveal how the care crisis is an intersectional crisis of social reproduction worsened by both austerity and COVID-19. We do this through an analysis of a small set of interviews with South Asian older women with care needs, conducted during the first period of UK national lockdown in 2020. This was a pilot study, focusing on the challenges faced in accessing formal and informal care during this period of the pandemic. The experiences, fears and vulnerabilities that came through in the interviews are located within a broader analysis of the racialized care crisis – one that reveals the long-term harms that austerity, including ‘austerity Islamophobia,’ generated for these older women and their families as they struggled to provide and access un/paid care