Phage and the Origins of Molecular Biology

edited by John Cairns, Gunther S. Stent, and James D. Watso

Chewed Out: An Experimental Link between Food Material Properties and Repetitive Loading of the Masticatory Apparatus in Mammals

Using a model organism (rabbits) that resembles a number of mammalian herbivores in key aspects of its chewing behaviors, we examined how variation in dietary mechanical properties a ects food breakdown during mastication. Such data have implications for understanding phenotypic variation in the mammalian feeding apparatus, particularly with respect to linking jaw form to diet-induced repetitive loading. Results indicate that chewing frequency (chews/s) is independent of food properties, whereas chewing investment (chews/g) and chewing duration(s), which are proportional to repetitive loading of the jaws, are positively related to food sti ness and toughness. In comparisons of displacement-limited and stress-limited fragmentation indices, which respectively characterize the intraoral breakdown of tough and sti foods, increases in chewing investment and duration are linked solely to sti ness. This suggests that sti er foods engender higher peak loads and increased cyclical loading. Our ndings challenge conventional wisdom by demonstrating that toughness does not, by itself, underlie increases in cyclical loading and loading duration. Instead, tough foods may be associated with such jaw-loading patterns because they must be processed in greater volumes owing to their lower nutritive quality and for longer periods of time to increase oral exposure to salivary chemicals

Analysis of chronic rejection and obliterative arteriopathy: Possible contributions of donor antigen-presenting cells and lymphatic disruption

Sequential analysis of changes that lead to chronic rejection was undertaken in an animal model of chronic rejection and obliterative arteriopathy. Brown Norway rats are pretreated with a Lewis bone marrow infusion or a Lewis orthotopic liver allograft and a short course of immunosuppression. They are challenged 100 days later with a Lewis heterotopic heart graft without immunosuppression. The heart grafts in both groups undergo a transient acute rejection, but all rats are operationally tolerant; the heart grafts are accepted and remain beating for more than 100 days. Early arterial remodeling, marked by arterial bromodeoxyuridine incorporation, occurred in both groups between 5 and 30 days during the transient acute rejection. It coincided with the presence of interstitial (but not arterial intimal) inflammation and lymphatic disruption and resulted in mild intimal thickening. Significant arterial narrowing occurred only in the bone-marrow-pretreated rats between 60 and 100 days. It was associated with T lymphocyte and macrophage inflammation of the heart graft that accumulated in the endocardium and arterial intima and adventitia near draining lymphatics. There also was loss of passenger leukocytes from the heart graft, up-regulation of cytokine mRNA and major histocompatibility class II on the endothelium, and focal disruption of lymphatics. In contrast, long-surviving heart grafts from the Lewis orthotopic liver allograft pretreated group are near normal and freedom from chronic rejection in this group was associated with persistence of donor major histocompatibility class-II-positive hematolymphoid cells, including OX62+ donor dendritic cells. This study offers insights into two different aspects of chronic rejection: 1) possible mechanisms underlying the persistent immunological injury and 2) the association between immunological injury and the development of obliterative arteriopathy. Based on the findings, it is not unreasonable to raise the testable hypothesis that direct presentation of alloantigen by donor antigen-presenting cells is required for long-term, chronic-rejection-free allograft acceptance. In addition, chronic intermittent lymphatic disruption is implicated as a possible mechanism for the association between chronic interstitial allograft inflammation and the development of obliterative arteriopathy

Sex differences in the influence of body mass index on anatomical architecture of brain networks.

Background/objectivesThe brain has a central role in regulating ingestive behavior in obesity. Analogous to addiction behaviors, an imbalance in the processing of rewarding and salient stimuli results in maladaptive eating behaviors that override homeostatic needs. We performed network analysis based on graph theory to examine the association between body mass index (BMI) and network measures of integrity, information flow and global communication (centrality) in reward, salience and sensorimotor regions and to identify sex-related differences in these parameters.Subjects/methodsStructural and diffusion tensor imaging were obtained in a sample of 124 individuals (61 males and 63 females). Graph theory was applied to calculate anatomical network properties (centrality) for regions of the reward, salience and sensorimotor networks. General linear models with linear contrasts were performed to test for BMI and sex-related differences in measures of centrality, while controlling for age.ResultsIn both males and females, individuals with high BMI (obese and overweight) had greater anatomical centrality (greater connectivity) of reward (putamen) and salience (anterior insula) network regions. Sex differences were observed both in individuals with normal and elevated BMI. In individuals with high BMI, females compared to males showed greater centrality in reward (amygdala, hippocampus and nucleus accumbens) and salience (anterior mid-cingulate cortex) regions, while males compared to females had greater centrality in reward (putamen) and sensorimotor (posterior insula) regions.ConclusionsIn individuals with increased BMI, reward, salience and sensorimotor network regions are susceptible to topological restructuring in a sex-related manner. These findings highlight the influence of these regions on integrative processing of food-related stimuli and increased ingestive behavior in obesity, or in the influence of hedonic ingestion on brain topological restructuring. The observed sex differences emphasize the importance of considering sex differences in obesity pathophysiology

Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis

Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere’s proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system

Preparation of amino acids and derivatives and their effect on the growth of Lactobacillus arabinosus

The d- and l-isomers of the following derivatives of valine, leucine, and tyrosine were prepared: the formyl, phthalyl, and prolyl derivatives of valine and leucine; the methyl ester hydrochlorides of valine and leucine; the glycyl derivatives of leucine; benzoyl, 3-amino, and 3-nitro tyrosine; the ethyl esters of tyrosine and benzoyl tyrosine; and benzoyl tyrosylamide;Of these, the prolyl and phthalyl derivatives of d-leucine, d-valine, and l-valine; the methyl ester hydrochlorides of d- and l-valine; the 3-amino and 3-nitro derivatives of d-tyrosine; and benzoyl-d-tyrosine ethyl ester were new compounds and constants for them were reported;High levels of glycine were found to inhibit the growth of L. arabinosus. The relationship between this inhibition and similar results reported in the literature for Streptococcus lactis was discussed;High levels of d-leucine and d-valine were also found to inhibit the growth of L. arabinosus. The same levels of l-leucine, l-valine, l-alanine, and d-alanine were without appreciable effect. Possible correlations between these results and the nutritional requirements of the organism, the structure of the amino acids, and the amino acids obtained from gramicidin were discussed;Of the valine, leucine, and tyrosine derivatives made, none seemed to show antipodal specificity. 3-Amino-l-tyrosine, 3-amino- d-tyrosine, d- and l-leucine methyl esters, and the phthalyl derivatives of both d- and l-leucine and valine showed more activity than d-leucine, although none of the activities was very high

Evolving Clustering Algorithms And Their Application For Condition Monitoring, Diagnostics, & Prognostics

Applications of Condition-Based Maintenance (CBM) technology requires effective yet generic data driven methods capable of carrying out diagnostics and prognostics tasks without detailed domain knowledge and human intervention. Improved system availability, operational safety, and enhanced logistics and supply chain performance could be achieved, with the widespread deployment of CBM, at a lower cost level. This dissertation focuses on the development of a Mutual Information based Recursive Gustafson-Kessel-Like (MIRGKL) clustering algorithm which operates recursively to identify underlying model structure and parameters from stream type data. Inspired by the Evolving Gustafson-Kessel-like Clustering (eGKL) algorithm, we applied the notion of mutual information to the well-known Mahalanobis distance as the governing similarity measure throughout. This is also a special case of the Kullback-Leibler (KL) Divergence where between-cluster shape information (governed by the determinant and trace of the covariance matrix) is omitted and is only applicable in the case of normally distributed data. In the cluster assignment and consolidation process, we proposed the use of the Chi-square statistic with the provision of having different probability thresholds. Due to the symmetry and boundedness property brought in by the mutual information formulation, we have shown with real-world data that the algorithm’s performance becomes less sensitive to the same range of probability thresholds which makes system tuning a simpler task in practice. As a result, improvement demonstrated by the proposed algorithm has implications in improving generic data driven methods for diagnostics, prognostics, generic function approximations and knowledge extractions for stream type of data. The work in this dissertation demonstrates MIRGKL’s effectiveness in clustering and knowledge representation and shows promising results in diagnostics and prognostics applications

Diffusion tensor MRI of the corpus callosum in amyotrophic lateral sclerosis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106143/1/jmri24218.pd

A method for concentrating dilute protein solutions

A method for concentrating dilute protein solution