Functional Motifs in SIAMESE, a Plant Cyclin-Dependent Kinase Inhibitor

SIAMESE (SIM) and SIAMESE-RELATED-PROTEIN1 (SMR1), the founding members of the SIM/SMRs gene family, suppress mitosis and onset of endoreplication in the Arabidopsis’s trichome and sepal development, respectively, and hence have been suggested to be CDK inhibitors. In this study, I have investigated the exact role of SIM and SMRs and their evolutionarily conserved function throughout land plant evolution. Using split luciferase complementation (SLC), I have shown that both SIM and a distantly related a bryophyte “Physcomitrella patens” SMR (pSMR1) interacts with multiple types of Cyclin Dependent Kinases (CDKs). I have multiple lines of evidence that establish SIM and SMRs as CDKs inhibitors and demonstrating that their evolutionary function is conserved. Almost all SIAMESE-RELATED PROTEINS (SMRs) of Arabidopsis as well as a SMR from the bryophyte Physcomitrella patens complement the sim mutant phenotype strongly. Genetic studies of sim mutants in combination with cyclind and cdkb1 mutants also support the conclusion that SIM inhibits the activity of both CDKA;1 and CDKB1;1-containing complexes. In an in vitro kinase assay, SIM inhibits CDK kinase activity; moreover, the Physcomitrella SMR also inhibits the same set of CYC/CDK complexes as SIM. These results indicate that SIM and other SMRs inhibit multiple CDK complexes and share a molecular mechanism that is conserved among all land plants. Finally, we have investigated the functional role of conserved protein sequence motifs in SIM. Two motifs, termed Motif-1 and Motif-2, play important roles in SIM function. Surprisingly, a motif previously thought to be a putative cyclin-binding motif is not essential for function of SIM. We have also identified a putative CDK phosphorylation site in Motif-1, and two nuclear localization sequences that are essential for SIM function. The work described here gives new insights into the biochemical role of SIM in regulating the cell cycle. The conserved function of widely divergent SMRs indicates that this protein family plays important roles in all land plants. These studies will provide a foundation for future work on the biochemical functions of SIM in the cell cycle, as well as for understanding the roles of individual SMRs in plant growth and development

Decision Making and Reform Within the United States Criminal Justice System

The United States Criminal Justice System has undergone massive legislative reform in the past decade. These reforms have prompted a demand to analyze the benefits and potential unintended consequences of proposed policies and legislation. The following dissertation measures policy implications across three types of actors in the criminal justice system: 911 call-takes, prosecutors, and law enforcement. As most citizen-officer interactions arise from 911 calls for service, the first chapter of this dissertation is a study on the “priming” effect 911-call-takers have on officer decision to arrest and use force on calls for service in Dallas, Texas (2013-2018). In this work, I leverage random assignment of incoming calls to 911- call-takers to explore the effect of call-takers’ high propensity to mention Hispanic/Latino, Black or White race on call outcomes. I find that marginal assignment of a call-taker with a high propensity to mention Black, Latino and White races results in a decrease in Black and Latino arrests and decrease in Black force use incidents compared to calls where no race is mentioned. The novel contribution of this research is to fill a gap in the empirical literature of 911-call-taker idiosyncrasies in transcribing information on officer decision-making. The second chapter of this work explores the role of a recent California legislative reform, Proposition 57, on the role of prosecution. The value of a criminal case, often determined by identifying the level of punishment that is appropriate given the severity of the offense, can be determined by potential consequences for a defendant, harm being redressed, and public, office, or prosecutors’ interests. Actors within the legal process must handle cases according to the value of the case while facing time and resource constraints. Legislation that changes the determinants of a case’s value will likewise affect the behavior of the agents. Given a case that is deemed to have a higher value, a rational agent prioritizes select cases and dispenses more readily with other lower value cases. Three testable predictions result from this model: (i) prosecutors seek the higher value for threshold cases; (ii) prosecutors resolve lesser cases quickly, through not filing, diversion, or plea; (iii) prosecutors adopt alternative consequences to offset any decrease in cases’ value. We test this hypotheses within the context of California’s recent legislation, Proposition 57, using difference-in-differences analysis. Our results support these predictions, legislation introduction contributes to case valuation. The third chapter examines the effect of a low priority local initiative on contracted and non-contracted police and prosecutors. Moreover, the extant empirical literature has primarily focused on how norms affect the design of legal rules, paying less attention to their role in the enforcement or prosecution of laws. This work investigates whether social norms affect law enforcement and prosecution practices when laws and norms are not necessarily aligned. This empirical analysis focuses on the impact of the adoption of a low priority initiative (LPI) on police and prosecutor behavior in Los Angeles County. LPIs are not legally binding and while such initiatives signal underlying norms, they may conflict with police and prosecutor preferences. Results suggest that following the introduction of an LPI there is a rise in the number of misdemeanor arrests, but not in the rate that misdemeanor marijuana offenses are dismissed. We then relax our parallel trends assumption in our main analysis using synthetic difference-in-differences and show that results remain consistent. We conclude that law enforcement preferences have a stronger influence over law enforcement behavior than community norms, while prosecutor behavior is unchanged with regards to the local norms

Strategies to succeed in an emerging market: a study of Australian service sector MNEs in India

This study focuses on post entry strategies of Multinational enterprises (MNEs) from a developedeconomy (Australia) operating in an emerging market (India). The research is organised around two core questions: (a) What are the post entry institutional challenges for service sector MNEs operating in an emerging market and (b) How do firms respond to institutional distance following their initial entry into an emerging economy? These questions are closely allied to the fundamental questions confronting international business (IB) such as “What drives firm strategy in international business (IB)?” and “What determines the success and failure of firms around the world?” (Peng et al., 20081920). This study draws on institutional theory (IT) and the network perspective to identify challenges faced by Australian service MNEs in India and the strategies they adapt to mitigate the liability of foreignness (LOF). The institutions in emerging economies are quite different from those in the developed economies, and recent research suggests that both formal and informal institutions, more commonly known as the "rules of the game" (North 1990) have an impact on the strategy and operations of MNEs (Hoskisson, et al., 2000; Wright, et al., 2005). Operating in emerging markets is challenging as the rule of law is poorly enforced (Hoskisson et al., 2000), proprietary technology and knowledge cannot be protected through enforceable legal mechanisms (Delios and Henisz, 2000) and there are large differences in culture and business norms. Contemporary institutional theory (Scott, 1995) indicates that, in order to survive, organisations must conform to the rules and belief systems prevailing in the environment (DiMaggio and Powell, 1983; Meyer and Rowan, 1977). Scott (1995) defined the institutional environment in terms of three pillars - regulative, normative and culturalcognitive. These unfamiliar institutions in the emerging markets often lead to unforeseen transaction costs as a result of which MNEs struggle to implement successful strategies in emerging markets. This thesis describes how the Australian service MNEs adaptively curb these costs by developing strategies that suit emerging markets as they acquire relevant local knowledge, re-script mental models and adapt plans and tactics. This study investigates key areas of concern to MNEs seeking competitive advantage in emerging markets through the development of superior strategies post-entry within the institutional framework of India. The AT. Kearney FDl Confidence Index 2007 rates India as the second most attractive destination for FDI. Its dynamic environment provides a rich context for examining the success strategies of Australian service MNEs. Finding effective strategies that can overcome the challenges of operating in an emerging market is the central issue in this thesis

Mass-based separation of active Brownian particles in an asymmetric channel

The inertial effects should be considered for micro- and nano-swimmers moving in a low-density medium confined by irregular structures that create entropic barriers, where viscous effects are no longer paramount. Here, we present a separation mechanism of self-propelled particles in a two-dimensional asymmetric channel, which leads to the drift of particles of different masses in opposite directions. In particular, this mechanism is based on the combined action of the spatial asymmetry of the channel structure, temporal asymmetry inherent in particles dynamics, and an external static force. This work is relevant for potential applications that can be found in the development of lab-on-a-chip devices and artificial channels for separating particles of different masses.Comment: 6 pages, 5 figures. This article is submitted to the journa

Structural and genetical studies on legumin of pisum sativum L. and vicia faba L.

studies have been made on the structure and genetics of the major seed storage protein, legumin, in Pisum sativum L. and Vicia faba L. Two dimensional gel electrophoresis, using non-reducing conditions in the first dimension and reducing conditions in the second dimension, used in conjunction with other different combinations of various electrophoretic techniques, has been found to be of great value in elucidating the structure of legumin. In both these legumes, legumin has been shown to be composed of a number of subunit pairs of different molecular weights, Vicia legumin (subunit pairs of mol. wt. 37,000-79,000) being more heterogeneous in this respect than the Pisum legumin (subunit pairs of mol. wt. 35,000-58,000). The subunit pairs are associated into hexameric molecules by non-covalent interactions? there exist a number of different molecular forms containing the subunit pairs in different combinations. Each subunit pair contains a large, relatively acidic subunit (mol. wt. 22700-58,000 in Vicia and 24,500-43,000 in Pisum? pI range 4.6-6.1 in Vicia and 4.85-6.15 in Pisum) and a smaller, relatively basic subunit (mol. wt. 21,000-23,000 in Vicia and 20,700-22,700 in Pisum; pI range 8.2-8.5 in Vicia and 6.2-8,0 in Pisum) linked covalently by one or more disulphide bonds. Genetic studies on Pisum sativum have shown that various legumin subunits all followed monogenic inheritance the alleles showing co-dominance with respect to each other. The genes for some but not all different types of legumin subunits have been shown to be inherited independently. The gene(s) for the acidic subunits of the major legumin subunit pair (s) is located 15 map units distant from the t l locus on the side away from the r locus on chromosome 7. A further storage protein gene has been mapped in that the gene for the convicilin subunits is strongly linked to the locus k on chromosome 2

Studies on antimicrobial activity of Lawsonia inermis L. against different strains of bacteria and fungi

Natural plant products are a significant source of synthetic and traditional medicines. The majority of the world population, especially in developing countries, is dependent on herbal formulations for their primary health care needs. Lawsonia inermis is a popular medicinal plant and possess many pharmacological properties. The present study was carried out to estimate the antimicrobial activity of L inermis leaves of the mother plant, regenerated plants and callus extract to justify the pharmaceutical aspect of the plant to provide herbal plant products as phytochemistry in Ayurveda as well as ethnobotanical aspect of the plant.The antimicrobial activity was determined with the help of the agar well diffusion method by using some Gram-positive;Bacillu subtilius MTCC441, Bacillus cereus MTCC430, Staphylococcus aureus MTCC96,Gram-negative; Escherichia coli MTCC1885,Pseudomonas aeruginosa  MTCC424 and fungal strains Candida albicans MTCC227.Leaves and callus extract were tested against these microorganisms in different types of solvent as Methanolic, Ethanolic, Aqueous, Acetone, Hexane, Chloroform and Diethyl ether were investigated by agar well diffusion method. Different extraction procedures were done by using the soxhlet apparatus.Dilutions were made for the extract and it was noticed that the zones of inhibitions were increased ith the concentration of the extracts. Methanolic leaves extract was found best extract for antimicrobial activity of L. inermis in comparison to other extracts.The maximum zone of inhibition was 13.79±1.7mm in methanolic extracts of leaves against B. subtilis and the minimum zone of inhibition was noticed  09.40±1.7   mm against B. cereus.The value of the zone of inhibition was more in the case of leaves extracts as compared to callus extracts.This study showed that methanolic leaves extracts of L. inermis inhibit the growth of microorganisms dose-dependently.The leaves of Lawsonia inermis support the traditional use of the plant in therapy of bacterial infection

Clustering of chemically propelled nanomotors in chemically active environments

Synthetic nanomotors powered by chemical reactions have been designed to act as vehicles for active cargo transport, drug delivery as well as a variety of other uses. Collections of such motors, acting in consort, can self-assemble to form swarms or clusters, providing opportunities for applications on various length scales. While such collective behavior has been studied when the motors move in a chemically inactive fluid environment, when the medium in which they move is a chemical network that supports complex spatial and temporal patterns we show that collective behavior changes. Spatial patterns in the environment can guide and control motor collective states, and interactions of the motors with their environment can give rise to distinctive spatiotemporal motor patterns. The results are illustrated by studies of the motor dynamics in systems that support Turing patterns and spiral waves. This work is relevant for potential applications that involve many active nanomotors moving in complex chemical or biological environments.Comment: 7 pages, 5 figures. This article is submitted to the journa

An unusual presentation of low ulnar nerve palsy: a case report

Ulnar nerve compression at the Guyon’s canal is an uncommon cause of ulnar nerve neuropathy. Among various reasons like trauma, non-union of hook of hamate, anomalous muscle anatomy, thrombosis of the ulnar artery or pseudoaneurysm, ganglion is a common lesion which can compress the ulnar nerve at this site. With proper history taking and physical examination consisting of assessing motor functions and sensation of the hand, a clinician can localize the site of the lesion. Ultrasound is cheap and non-invasive technique which helps to localize the site of lesion and can suggest the nature of the lesion. Surgical decompression of the canal and careful removal of the lesion can help ameliorate the symptoms. In our study the patient presented with sudden onset weakness of the right hand and symptoms progressing within one and half month. With proper muscle charting, sensory examination and with the help of sonography, the main culprit was localized to Guyon’s canal. Excision of the lesion helped in recovery of hand function within 5 months