Modeling individual’s aging within a bacterial population using a pi-calculus paradigm

We propose an aging mechanism which develops in artificial bacterial populations fighting against antibiotic molecules. The mechanism is based on very elementary information gathered by each individual and elementary reactions as well. Though we do not interpret the aging process in strictly biological terms, it appears compliant with recent studies on the field, and physically feasible. The root of the aging mechanism is an adaptation strategy based on a thresholding operation that derives from theoretical results on stochastic monotone games. The methods for implementing it denote their rationale in that they represent a sophisticated dialect of pi-calculus, a widespread computational paradigm for implementing dynamics of massive populations with bipolar reactions. As a result we may implement processes that explain some typical patterns of the evolution of the immunosystems.     

Intracranial meningioma and astrocytoma in the same patient. Case report and review of the literature

St. Jude Medical Center, a Sisters of St. Joseph Health System Corporation in Fullerton California, in their efforts at work redesign, realized that the success of a patient-centered care delivery system largely depended upon successful selection of the most suitable team members. The interviewing and selection process used at St. Jude Medical Center includes a structured interview process with integration of both situational and behavioral styles in conjunction with objective rating scales and values driven questions. A common thread woven into the hiring criteria for all levels of personnel in the patient-centered care delivery model was creativity, adaptability, interpersonal skills and compatibility of values. Additionally, the clinical competence of the caregiver within the scope of practice/responsibility was essential for their expanded role. Management and leadership abilities for the managers are also addressed in the interview and selection process to provide the best team members for the overall success of the patient-care redesign.     

Selection methods regulate evolution of cooperation in digital evolution

A key, yet often neglected, component of digital evolution and evolutionary models is the ‘selection method’ which assigns fitness (number of offspring) to individuals based on their performance scores (efficiency in performing tasks). Here, we study with formal analysis and numerical experiments the evolution of cooperation under the five most common selection methods (proportionate, rank, truncation-proportionate, truncation-uniform and tournament). We consider related individuals engaging in a Prisoner''s Dilemma game where individuals can either cooperate or defect. A cooperator pays a cost, whereas its partner receives a benefit, which affect their performance scores. These performance scores are translated into fitness by one of the five selection methods. We show that cooperation is positively associated with the relatedness between individuals under all selection methods. By contrast, the change in the performance benefit of cooperation affects the populations’ average level of cooperation only under the proportionate methods. We also demonstrate that the truncation and tournament methods may introduce negative frequency-dependence and lead to the evolution of polymorphic populations. Using the example of the evolution of cooperation, we show that the choice of selection method, though it is often marginalized, can considerably affect the evolutionary dynamics.     

Pectolytic Enzymes in Sweet Bell Peppers (Capsicum annuum L.)

Low levels of polygalacturonase (PG) and pectinesterase (PE) activities were quantitated in sweet bell peppers at four stages of maturity based on surface ground color (dark green, light green, turning, and red). The PG activity increased during pepper ripening and was maximal at the turning stage while the PE activity declined during ripening and was maximal at the light green stage. Pepper texture measurements were found to decline concomitantly with the increase in PG activity. Pepper PG showed pH optimum between 4.8 to 5.0 and increased temperature stability with advanced ripening. Compared to tomatoes, pepper PG activity was 116- to 164-fold lower and pepper PE activity was 429- to 1900-fold lower than the corresponding tomato enzymes.     

Bioluminescent Optogenetics: A Novel Experimental Therapy to Promote Axon Regeneration after Peripheral Nerve Injury

Functional recovery after peripheral nerve injury (PNI) is poor, mainly due to the slow and incomplete regeneration of injured axons. Experimental therapies that increase the excitability of the injured axons have proven remarkably successful in promoting regeneration, but their clinical applicability has been limited. Bioluminescent optogenetics (BL-OG) uses luminopsins, fusion proteins of light-generating luciferase and light-sensing ion channels that could be used to increase neuronal excitability if exposed to a suitable substrate. Excitatory luminopsins were expressed in motoneurons of transgenic mice and in wildtype mice transduced with adeno-associated viral vectors. Intraperitoneal administration of coelenterazine (CTZ), a known luciferase substrate, generated intense bioluminescence in peripheral axons. This bioluminescence increased motoneuron excitability. A single administration of CTZ immediately after sciatic nerve transection and repair markedly enhanced motor axon regeneration. Compound muscle action potentials were 3–4 times larger than controls by 4 weeks after injury. The results observed with transgenic mice were comparable to those of mice in which the luminopsin was expressed using viral vectors. Significantly more motoneurons had successfully reinnervated muscle targets four weeks after nerve injury in BL-OG treated mice than in controls. Bioluminescent optogenetics is a promising therapeutic approach to enhancing axon regeneration after PNI.     

Unraveling the Link between Interferon-α and Systemic Lupus Erythematosus: From the Molecular Mechanisms to Target Therapies

Systemic lupus erythematosus (SLE) is a chronic, systemic autoimmune disease with a wide range of clinical expressions. The kidney is often affected, usually within 5 years of the onset of SLE, and lupus nephropathy (LN) carries a high risk for increased morbidity. The clinical heterogeneity of the disease is accompanied by complex disturbances affecting the immune system with inflammation and tissue damage due to loss of tolerance to nuclear antigens and the deposition of immune complexes in tissues. Several studies have reported that in human SLE, there is an important role of the Type-I-interferons (INF) system suggested by the upregulation of INF-inducible genes observed in serial gene expression microarray studies. This review aims to describe the transduction pathways of Type-I-interferons, in particular INFα, and its immune-regulatory function in the pathogenesis of SLE and, in particular, in LN. In addition, recent novelties concerning biologic therapy in LN will be discussed.     

Metabolic Pathways for Observed Impacts of Crop Load on Floral Induction in Apple

The triggers of biennial bearing are thought to coincide with embryonic development in apple and occurs within the first 70 days after full bloom (DAFB). Strong evidence suggests hormonal signals are perceived by vegetative apple spur buds to induce flowering. The hormonal response is typically referred to as the floral induction (FI) phase in bud meristem development. To determine the metabolic pathways activated in FI, young trees of the biennial bearing cultivar ‘Nicoter’ and the less susceptible cultivar ‘Rosy Glow’ were forced into an alternate cropping cycle over five years and an inverse relationship of crop load and return bloom was established. Buds were collected over a four-week duration within 70 DAFB from trees that had maintained a four-year biennial bearing cycle. Metabolomics profiling was undertaken to determine the differentially expressed pathways and key signalling molecules associated with biennial bearing. Marked metabolic differences were observed in trees with high and low crop load treatments. Significant effects were detected in members of the phenylpropanoid pathway comprising hydroxycinnamates, salicylates, salicylic acid biosynthetic pathway intermediates and flavanols. This study identifies plant hormones associated with FI in apples using functional metabolomics analysis.