Elucidation of molecular kinetic schemes from macroscopic traces using system identification

Overall cellular responses to biologically-relevant stimuli are mediated by networks of simpler lower-level processes. Although information about some of these processes can now be obtained by visualizing and recording events at the molecular level, this is still possible only in especially favorable cases. Therefore the development of methods to extract the dynamics and relationships between the different lower-level (microscopic) processes from the overall (macroscopic) response remains a crucial challenge in the understanding of many aspects of physiology. Here we have devised a hybrid computational-analytical method to accomplish this task, the SYStems-based MOLecular kinetic scheme Extractor (SYSMOLE). SYSMOLE utilizes system-identification input-output analysis to obtain a transfer function between the stimulus and the overall cellular response in the Laplace-transformed domain. It then derives a Markov-chain state molecular kinetic scheme uniquely associated with the transfer function by means of a classification procedure and an analytical step that imposes general biological constraints. We first tested SYSMOLE with synthetic data and evaluated its performance in terms of its rate of convergence to the correct molecular kinetic scheme and its robustness to noise. We then examined its performance on real experimental traces by analyzing macroscopic calcium-current traces elicited by membrane depolarization. SYSMOLE derived the correct, previously known molecular kinetic scheme describing the activation and inactivation of the underlying calcium channels and correctly identified the accepted mechanism of action of nifedipine, a calcium-channel blocker clinically used in patients with cardiovascular disease. Finally, we applied SYSMOLE to study the pharmacology of a new class of glutamate antipsychotic drugs and their crosstalk mechanism through a heteromeric complex of G protein-coupled receptors. Our results indicate that our methodology can be successfully applied to accurately derive molecular kinetic schemes from experimental macroscopic traces, and we anticipate that it may be useful in the study of a wide variety of biological systems

Reduce Tall Fescue Toxicosis in \u3cem\u3eFestuca arundinacea\u3c/em\u3e Forage Systems with Legumes

Tall fescue (Lolium arundinaceum = Festuca arundinacea) is an important cool-season grass because of persistence and spring and autumn productivity. Most existing tall fescue pastures in Tennessee are Kentucky-31 (KY-31) and are infested with the endophytic fungus Neotyphodium coenophialum that causes tall fescue toxicosis. Symptoms in beef cattle include reduced rates of gain, poor conception rates, decreased dry matter intake, a long rough haircoat in summer, and very low serum prolactin. Earlier studies indicated that the performance of cattle grazing endophyte-free (EF) tall fescue is superior to that of cattle grazing endophyte-infected (EI) tall fescue (Fribourg et al., 1995). However, EF tall fescue is not as persistent as EI. Addition of clovers to tall fescue pastures is a recommended practice. Our objective was to compare forage quality, in vitro dry matter disappearance, dry matter intake, and animal performance of EI and EF KY-31 pastures, and inclusion of legumes

Orchardgrass Pastures for Early-Weaned Beef Calves

Orchardgrass (Dactylis glomerata) grown alone or with ladino white (Trifolium repens) and red (T. pratense) clovers, provides a high quality March to June pasture. However, many beef producers have their cows calving in January-March, thus producing offspring that are too young to utilize spring forage well. As an alternative, some producers have their cows bred so that calves are born in autumn (September-November). By spring, these calves are old enough to consume pasture forage. The few earlier studies on early weaning of fall-born calves consist of drylot feeding of high quality hay or concentrates. This study evaluated the potential of orchardgrass and orchardgrass clover pastures to meet the nutritional needs of early-weaned fall-born beef calves (Bos taurus). Fallborn steers, 4.5-mo old, weighing about 144 kg, were used in each of 3 yr. Twenty-four were weaned and allotted at random to one of four duplicate pasture treatments: (1) TN-Syn-2 orchardgrass, grown alone or (2) with ladino white and red clovers ; (3) ‘Benchmark’ orchardgrass, grown alone or (4) with the clovers; another 24 remained with their dams. Early-weaned calves on high quality pastures performed well, with daily gains between 640 and 925 g d-1. Dams which were not suckled were in better body condition going into the summer than those with calves

MIXED MODELS COMBINED ANALYSIS OF INDEPENDENT GRAZING TRIALS

The mixed models procedure (MMP) was used to analyze pooled data sets from 12 independent studies over 13 yr at 9 locations in 7 states to provide combined estimates of daily gains by beef steers grazing tall fescue pastures with different levels of infestation by Acremonium coenophialum, with and without clover. Spring, summer, and combined spring + summer data were analyzed separately. The MMP permitted estimation of the fixed effects of treatments over a broad inference space of future years and different tall fescue pastures over a wide geographic range, detected some relationships not apparent in the individual studies, and provided a more coherent body of information than do the results obtained from each discrete study. Logistical and financial constraints that force undesirable compromises in the conduct of future grazing and other expensive or time-consuming research may be avoided by using MMP within the context of cooperative projects

Grazing Endophyte Infested Tall Fescue and Changes in Bovine Blood Components and Gain

Tall fescue (Festuca arundinacea) is utilized on more than 15 million ha of pasture in the eastern USA and over 80% of the plants in this area are infested with the endophyte Neotyphodium coenophialum. Tall fescue toxicosis results from consumption of the infested (E+) grass host and is an important problem that causes considerable economic loss to producers. However, the agronomic attributes of tall fescue make it an attractive forage because of its ability to withstand cool temperatures, drought, poor soil conditions and intensive defoliation. There is need to understand mechanisms of animal physiology that are affected by the alkaloids produced by the endophyte/grass association. Blood serum samples were collected from steers (Bos taurus) grazing either E+ or endophyte free (E-) tall fescue in spring and summer during three consecutive years and were related to animal performance. Consistent and significant changes associated with E+ tall fescue were noted for daily gain, prolactin, albumin/globulin ratio, alanine aminotransferase, cholesterol, creatinine, globulin, total bilirubin, total serum protein, copper, red blood cells, mean corpuscular volume, mean corpuscular hemoglobin, and eosinophils. Thus, repeatable changes that occur in serum biochemical and blood cellular values of cattle grazing E+ tall fescue were identified and will aid in understanding the pathogenesis of the toxicosis

Forward Analysis and Model Checking for Trace Bounded WSTS

We investigate a subclass of well-structured transition systems (WSTS), the bounded---in the sense of Ginsburg and Spanier (Trans. AMS 1964)---complete deterministic ones, which we claim provide an adequate basis for the study of forward analyses as developed by Finkel and Goubault-Larrecq (Logic. Meth. Comput. Sci. 2012). Indeed, we prove that, unlike other conditions considered previously for the termination of forward analysis, boundedness is decidable. Boundedness turns out to be a valuable restriction for WSTS verification, as we show that it further allows to decide all $\omega$-regular properties on the set of infinite traces of the system

Evaluation of the antigen-antibody complex vaccine of Gumboro disease administered in ovo in broiler chickens challenged with F52/70 strain

El objetivo del presente estudio fue evaluar la protección y seguridad del complejo vacunal antígeno-anticuerpo administrado in ovo frente a un desafío experimental con la cepa F52/70 de la Enfermedad de Gumboro en pollos de carne. Se utilizaron 450 pollos de la línea Cobb Vantress, de un día de edad, distribuidos en tres grupos: Grupo A, vacunado, vía agua de bebida, a los 9 días con la cepa intermedia suave tipo Lukert y revacunado a los 19 días con la cepa intermedia intermedia 2512; grupo B, vacunado vía in ovo a los 18 días de incubación con el complejo vacunal antígeno-anticuerpo; y grupo C, control no vacunado. A los 35 días de edad, 20 aves de cada grupo fueron desafiadas, vía ocular, con la cepa F52/70 de la enfermedad de Gumboro. La seguridad del complejo vacunal se evaluó semanalmente hasta los 47 días de edad mediante la determinación del índice bursal, lesiones macroscópicas, lesiones histopatológicas de bursa y respuesta serológica. Las lesiones post desafío se caracterizaron por edema y hemorragias petequiales en la bursa. El grupo B presentó la mejor protección con 75% comparado con el grupo A (68%) y el grupo control (30%). Las lesiones post desafío se caracterizaron por edema y hemorragias petequiales en la bursa. En las aves no desafiadas no se observó diferencias significativas entre los grupos A y B para el índice bursal y lesiones histopatológicas hasta los 28 días de edad; sin embargo, a partir de los 35 días el grupo A fue significativamente diferente de los grupos B y C (p<0.05). Al final del estudio el grupo A obtuvo títulos de 1948 y 2047 más de anticuerpos que el grupo B y el control, respectivamente.The objective of the study was to evaluate the protection and safety for in ovo vaccination against Infection Bursal Disease. Cobb Vantress broilers of one day of age (n=450) were distributed in three groups: Group A, vaccinated at 9 and 19 days with two commercial live vaccines containing Lukert and 2512 strains, respectively; group B, vaccinated in ovo with the antigen-antibody complex at 18 days of incubation; and group C, unvaccinated. At 35 days of age, 20 birds from each group were challenged, ocular via, with the F52/70 strain of Gumboro disease. The security of the complex vaccine was evaluated weekly until 47 days of age by determining the bursal index, gross lesions, histopathological lesions of the bursa, and serological response. Group B showed the best protection with 75% as compared with groups A (68%) and C (30%). Injuries after challenge were characterized by swelling, bleeding, and petechiae in the bursa. In non-challenged birds were none significant differences between groups A and B for the index and bursal histopathology lesions until 28 days of age; however, group A differed from groups B and C at 35 days of age (p<0.05). At the end of the study, group A had 1948 and 2047 antibodies titers higher than groups B and control respectively

Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors

Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects