Formation and Function of the Rbl2p-beta-Tubulin Complex

The yeast protein Rbl2p suppresses the deleterious effects of excess beta-tubulin as efficiently as does alpha-tubulin. Both in vivo and in vitro, Rbl2p forms a complex with beta-tubulin that does not contain alpha-tubulin, thus defining a second pool of beta-tubulin in the cell. Formation of the complex depends upon the conformation of beta-tubulin. Newly synthesized beta-tubulin can bind to Rbl2p before it binds to alpha-tubulin. Rbl2p can also bind beta-tubulin from the alpha/beta-tubulin heterodimer, apparently by competing with alpha-tubulin. The Rbl2p-beta-tubulin complex has a half-life of ~2.5 h and is less stable than the alpha/beta-tubulin heterodimer. The results of our experiments explain both how excess Rbl2p can rescue cells overexpressing beta-tubulin and how it can be deleterious in a wild-type background. They also suggest that the Rbl2p-beta-tubulin complex is part of a cellular mechanism for regulating the levels and dimerization of tubulin chains

Rbl2p, a yeast protein that binds to β-tubulin and participates in microtubule function in vivo

AbstractGenetic configurations resulting in high ratios of β-tubulin to α-tubulin are toxic in S. cerevisiae, causing microtubule disassembly and cell death. We identified three non-tubulin yeast genes that, when overexpressed, rescue cells from excess β-tubulin. One, RBL2, rescues β-tubulin lethality as efficiently as does α-tubulin. Rbl2p binds to β-tubulin in vivo. Deficiencies or excesses of either RbI2p or α-tubulin affect microtubule-dependent functions in a parallel fashion. RbI2p has functional homology with murine cofactor A, a protein important for in vitro assays of β-tubulin folding. The results suggest that RbI2p participates in microtubule morphogenesis but not in the assembled polymer

Representation and analysis of real-time control structures

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.Bibliography: p. 110-111.by Rowland Frank Archer, Jr.M.S

Student perceptions of adverse health events during ambulance clinical placements

This pilot study intended to augment current literature in the clinical placement field by investigating the frequency and nature of adverse health events experiences by paramedic students undertaking ambulance clinical placements. Supports accessed post event were also reviewed. A purposive sample of fifty-six paramedic students completed the questionnaire. The results indicate that a number of students experience adverse health events while on clinical placement, with fourteen cases of verbal abuse, one case of physical abuse, nine cases of sexualised behavior and seven cases of psychological distress reported. While some case related incidents were flagged by ambulance services and followed up by peer support, students did not initiate any formal support processes themselves. Moreover, no student filed a formal report regarding any of the incidents raised. The results of this pilot study require further investigation. In the interim, the benefits of clinical placements must be weighed against their risks, and processes put in place to minimize the risk to students undertaking clinical placements

Brownian particles with long and short range interactions

We develop a kinetic theory of Brownian particles with long and short range interactions. We consider both overdamped and inertial models. In the overdamped limit, the evolution of the spatial density is governed by the generalized mean field Smoluchowski equation including a mean field potential due to long-range interactions and a generically nonlinear barotropic pressure due to short-range interactions. This equation describes various physical systems such as self-gravitating Brownian particles (Smoluchowski-Poisson system), bacterial populations experiencing chemotaxis (Keller-Segel model) and colloidal particles with capillary interactions. We also take into account the inertia of the particles and derive corresponding kinetic and hydrodynamic equations generalizing the usual Kramers, Jeans, Euler and Cattaneo equations. For each model, we provide the corresponding form of free energy and establish the H-theorem and the virial theorem. Finally, we show that the same hydrodynamic equations are obtained in the context of nonlinear mean field Fokker-Planck equations associated with generalized thermodynamics. However, in that case, the nonlinear pressure is due to the bias in the transition probabilities from one state to the other leading to non-Boltzmannian distributions while in the former case the distribution is Boltzmannian but the nonlinear pressure arises from the two-body correlation function induced by the short-range potential of interaction. As a whole, our paper develops connections between the topics of long-range interactions, short-range interactions, nonlinear mean field Fokker-Planck equations and generalized thermodynamics. It also justifies from a kinetic theory based on microscopic processes, the basic equations that were introduced phenomenologically in gravitational Brownian dynamics, chemotaxis and colloidal suspensions with attractive interactions

Endemism in the genus Pertusaria (Pertusariales, lichenized Ascomycota) from the Galapagos Islands

This revision of Pertusaria in the Galapagos Islands documents twenty-four species, twenty-two being new to the archipelago. Secondary chemistry correlates well with morphology and anatomy and is particularly useful in distinguishing these taxa. Eight species are described as new to science, and seven are known only from the Galapagos: Pertusaria albineoides, P. cerroazulensis, P. darwiniana, P. medullamarilla, P. stictica, P. thioisidiata and P. xanthoisidiata. Pertusaria lueckingii is new, but it also occurs in Central America (El Salvador). Three new endemic varieties are described based on their chemistry: Pertusaria thioisidiata var. isidiogyrophorica, P. tejocotensis var. stictica and P. xantholeucoides var. thamnolica. In contrast with previous studies on other genera where rates of endemism of 8–10% were observed, in Pertusaria 30–37% of all species and 41–46% of all taxa are considered endemic

Evaluation of clinical prediction models (part 1): from development to external validation

Evaluating the performance of a clinical prediction model is crucial to establish its predictive accuracy in the populations and settings intended for use. In this article, the first in a three part series, Collins and colleagues describe the importance of a meaningful evaluation using internal, internal-external, and external validation, as well as exploring heterogeneity, fairness, and generalisability in model performance

Evaluation of clinical prediction models (part 1):from development to external validation

Evaluating the performance of a clinical prediction model is crucial to establish its predictive accuracy in the populations and settings intended for use. In this article, the first in a three part series, Collins and colleagues describe the importance of a meaningful evaluation using internal, internal-external, and external validation, as well as exploring heterogeneity, fairness, and generalisability in model performance