736 research outputs found
Hierarchy of Players in Swap Robust Voting Games
Ordinarily, the process of decision making by a committee through voting is modelled by a monotonic game the range of whose characteristic function is restricted to {0,1}. The decision rule that governs the collective action of a voting body induces a hierarchy in the set of players in terms of the a-priori influence that the players have over the decision making process. In order to determine this hierarchy in a swap robust game, one has to either evaluate a number-based power index (e.g., the Shapley-Shubik index, the Banzhaf-Coleman index) for each player or conduct a pairwise comparison between players in order to find out whether there exists a coalition in which player i is desirable over another player j as a coalition partner. In this paper we outline a much simpler and more elegant mechanism to determine the ranking of players in terms of their a-priori power using only minimal winning coalitions, rather than the entire set of winning coalitions.simple game; swap robust game; desirability; weak desirability; lexicographic ordering
Analysis of gene expression, regulation and function of three symbiotic ABC subfamily-B transporters in Medicago truncatula
The legume M. truncatula overcomes low soil nutrient conditions by forming symbiotic associations with nitrogen-fixing soil bacteria called rhizobia (Root Nodule Symbiosis) and fungi which assist in the acquisition of phosphate, collectively called arbuscular mycorrhizae (Arbuscular Mycorrhizal Symbiosis). Establishment of functional beneficial symbioses requires successful microbial infection. An initial
exchange of signalling molecules between the host and the microbe sets off extensive transcriptional reprogramming of the host developmental programme to accommodate the incoming microbe. Microbial lipochitooligosaccharide molecules trigger a signalling pathway comprising a core set of around seven genes common to both symbioses, central to which is the calcium calmodulin kinase, CCaMK. Here I describe the identification and characterization of three novel M. truncatula ATPBinding cassette containing sub-family B transporters, transcriptionally induced upon infection by both rhizobia and mycorrhizae; therefore named AMN for ABC transporters in Mycorrhization and Nodulation. Promoter-GUS expression reveals
that these genes are exclusive to infection structure containing root hair cells and arbuscule containing root cortical cells. I use different SYM pathway mutants to show that the induction of these transporters is dependent on CCaMK and other members of the symbiotic pathway. Conservation of these transporters across mycorrhizing angiosperms suggested an important evolutionary function therefore I identified and characterized single and double mutants. In the absence of any
aberrant symbiotic phenotype a triple mutant was also generated but remains to be characterized.
Since ABC sub-family B transporters in Arabidopsis are known to efflux auxin I also undertook a multipronged approach to identify a role for auxin in rhizobial infection. Using pharmacological and physiological assays I describe results that indicate a positive role for auxin in infection. Lastly I describe the nodulation phenotype of mtlax2 and mtiaa8; a homologue of the Arabidopsis AtAUX1 auxin influx carrier and an infection induced AUX/IAA repressor respectively. A lower nodule number in both mutants provide the first genetic evidence for auxin’s role in nodule
development
Hierarchy of players in swap robust voting games
Ordinarily, the process of decision making by a committee through voting is modelled by a monotonic game the range of whose characteristic function is restricted to {0,1}. The decision rule that governs the collective action of a voting body induces a hierarchy in the set of players in terms of the a-priori influence that the players have over the decision making process. In order to determine this hierarchy in a swap robust game, one has to either evaluate a number-based power index (e.g., the Shapley-Shubik index, the Banzhaf-Coleman index) for each player or conduct a pairwise comparison between players in order to find out whether there exists a coalition in which player i is desirable over another player j as a coalition partner. In this paper we outline a much simpler and more elegant mechanism to determine the ranking of players in terms of their a-priori power using only minimal winning coalitions, rather than the entire set of winning coalitions
A rulebook for peptide control of legume–microbe endosymbioses
Plants engage in mutually beneficial relationships with microbes, such as arbuscular mycorrhizal fungi or nitrogen-fixing rhizobia, for optimized nutrient acquisition. In return, the microbial symbionts receive photosynthetic carbon from the plant. Both symbioses are regulated by the plant nutrient status, indicating the existence of signaling pathways that allow the host to fine-tune its interactions with the beneficial microbes depending on its nutrient requirements. Peptide hormones coordinate a plethora of developmental and physiological processes and, recently, various peptide families have gained special attention as systemic and local regulators of plant–microbe interactions and nutrient homeostasis. In this review, we identify five \u27rules\u27 or guiding principles that govern peptide function during symbiotic plant–microbe interactions, and highlight possible points of integration with nutrient acquisition pathways
Studies on Phytochemical Analysis, Antioxidant, Antibacterial and Larvicidal Properties of the Acacia nilotica Fruit Extracts
In the present study fruit of Acacia nilotica was chosen to evaluate its antioxidant, larvicidal and antibacterial properties. Phytochemical screening of aqueous and alcohol extracts of the plant fruits affirmed the presence of carbohydrates, reducing sugar, phenol, flavonoid, terpenoid, saponin and steroid. The antioxidant properties of the aqueous and alcohol fruit extracts were noted as 10.11±0.035 and 9.75±0.023 mM of FeSO4 for Ferric Reducing Antioxidant Power (FRAP) assay respectively. The potency of antimicrobial activity of the aqueous and alcohol extract of A. nilotica fruit were tested against Pseudomonas aeruginosa, Staphylococcus aureus, Bacillussubtilis, and Escherichiacoli. The alcohol extract against E. coli, exhibited the highest antimicrobial activity. Aqueous extracts of A. nilotica fruit showed potential toxicity against Aedes albopictus larvae with LC50 value of 142.074 mg L-1. Present findings clearly indicated that A. nilotica fruit extracts could be most effectively used as a natural antioxidant, antibacterial and larvicidal agent
Increasing racial diversity in the North American Plant Phenotyping Network through conference participation support
A key goal of the North American Plant Phenotyping Network (NAPPN) annual conference is to cultivate a new generation of scientists from diverse backgrounds. As part of their effort to diversify the plant phenomics research community, NAPPN acquired funding to cover all attendance costs for participants from historically black colleges and universities (HBCU) for the 2022 annual meeting. Seven award recipients represented the first attendees from HBCUs in the conference’s 6-year history. In this commentary, we report on the impact of the conference awards, including lessons learned, and the future of the award
A study of peripheral neuropathy in cases of type-II diabetes mellitus patients with or without hypothyroidism
Background: Type 2 diabetic patients have a higher prevalence of thyroid disorders, particularly hypothyroidism. Peripheral neuropathy is a common and disabling complication of diabetes mellitus. Peripheral nervous system involvement in hypothyroidism is also a well-documented fact. Nerve conduction studies are generally considered to be the most sensitive and reproducible in the assessment of peripheral neuropathies. This study helped to determine the prevalence of peripheral neuropathy in diabetic hypothyroid patients as well as to compare it in diabetic patients with or without hypothyroidism. It compared the onset latency, amplitude, conduction velocity and F- wave latency of some nerves in type 2 diabetes mellitus patients with or without hypothyroidism.Methods: With RMS, EMG, EP MARK-II, nerve conduction studies are done in 30 cases (type 2 diabetes mellitus patients with hypothyroidism) and 30 controls (type 2 diabetes mellitus patients of diabetes without hypothyroidism) respectively, attending the Diabetic Clinic and Biochemistry Laboratory of North Bengal Medical College.Results: Data were treated with Unpaired t-Test. The study reveals that type 2 diabetes mellitus patients with hypothyroidism have higher prevalence of peripheral neuropathy. There is statistically significant (p<0.00) decrease in motor nerve conduction study in both right and left median nerves in diabetic patients with hypothyroidism than in diabetic patients without hypothyroidism.Conclusions: All diabetic patients should be screened for early detection of hypothyroidism as type 2 diabetic patients with hypothyroidism have higher prevalence of peripheral neuropathy. The nerve conduction study remains the most reliable, accurate, and sensitive method to evaluate peripheral nerve function
First record of a Leucosid crab<em> Paranursia abbreviata</em> Bell, 1855 from Devi estuary, Odisha Coast, India
117-119A leucosid crab Paranursia abbreviata Bell, 1855 is recorded for the first time from Odisha albeit from coastal waters of the Indian peninsula after half a century. Present study is an effort towards documentation of the species from Odisha, indicative of a range extension between the Coromandal coast and Gulf of Martaban, Myanmar
MtLAX2, a functional homologue of the Arabidopsis auxin influx transporter AUX1, is required for nodule organogenesis
Most legume plants can form nodules, specialized lateral organs that form on roots, and house nitrogen-fixing bacteria collectively called rhizobia. The uptake of the phytohormone auxin into cells is known to be crucial for development of lateral roots. To test the role of auxin influx in nodulation we used the auxin influx inhibitors 1-naphthoxyacetic acid (1-NOA) and 2-NOA, which we found reduced nodulation of Medicago truncatula. This suggested the possible involvement of the AUX/LAX family of auxin influx transporters in nodulation. Gene expression studies identified MtLAX2, a paralogue of Arabidopsis (Arabidopsis thaliana) AUX1, as being induced at early stages of nodule development. MtLAX2 is expressed in nodule primordia, the vasculature of developing nodules, and at the apex of mature nodules. The MtLAX2 promoter contains several auxin response elements, and treatment with indole-acetic acid strongly induces MtLAX2 expression in roots. mtlax2 mutants displayed root phenotypes similar to Arabidopsis aux1 mutants, including altered root gravitropism, fewer lateral roots, shorter root hairs, and auxin resistance. In addition, the activity of the synthetic DR5-GUS auxin reporter was strongly reduced in mtlax2 roots. Following inoculation with rhizobia, mtlax2 roots developed fewer nodules, had decreased DR5-GUS activity associated with infection sites, and had decreased expression of the early auxin responsive gene ARF16a. Our data indicate that MtLAX2 is a functional analog of Arabidopsis AUX1 and is required for the accumulation of auxin during nodule formation in tissues underlying sites of rhizobial infection
Genome-wide identification of <i>Medicago</i> peptides involved in macronutrient responses and nodulation
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