Use of Plant Extracts as an Effective Manner to Control Clostridium perfringens Induced Necrotic Enteritis in Poultry

Necrotic enteritis (NE) is an important concern in poultry industry since it causes economic losses, increased mortality, reduction of bird welfare, and contamination of chicken products for human consumption. For decades, the use of in-feed antimicrobial growth promoters (AGPs) has been the main strategy to control intestinal pathogens including Clostridium perfringens (CP), the causative agent of NE. However, the use of AGPs in animal diet has been linked to the emergence and transmission of antimicrobial resistance through food-borne microorganisms, which has led to the ban of AGPs in many countries. This scenario has challenged the poultry industry to search for safer alternative products in order to prevent NE. In this context, the utilization of natural plant extracts with antimicrobial properties appears as a promising and feasible tool to control NE in chicken. In this paper, we review the scientific studies analyzing the potential of plant extracts as alternative feed additives to reduce NE in poultry, with focus on two types of plant products that arise as promising candidates: tannins and essential oils. Some of these products showed antimicrobial activity against CP and coccidia in vitro and in vivo and are able to increase productive performance, emulating the bioactive properties of AGPs.Fil: Díaz Carrasco, Juan María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Redondo, Leandro Martin. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Redondo, Enzo Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dominguez, Johana Elizabeth. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chacana, A. P. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; ArgentinaFil: Fernandez Miyakawa, Mariano Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentin

Length of the artificial incubation in red-legged partridge (Alectoris rufa)

La incubación artificial de los huevos es una fase del manejo clave para la viabilidad de las granjas cinegéticas de perdiz roja (Alectoris rufa). Sin embargo, la duración de la incubación artificial y la dispersión de las eclosiones no han sido previamente cuantificadas en esta especie. Con este objetivo se analizaron cuatro ensayos de incubación artificial de huevos de perdiz roja procedentes de tres granjas cinegéticas del sur de España realizados incluyendo variabilidad de factores de manejo de los reproductores y de la incubación. La duración media de la incubación fue de 23,4 días, difiriendo entre ensayos (P = 0,004), con un valor modal de 23 días y finalizando la mayoría de las eclosiones (percentil 95) el día 24,5 de incubación. La eclosión mostró una distribución asimétrica positiva y leptocúrtica, como corresponde al patrón de eclosión de las especies precociales. Las eclosiones, que pueden comenzar el día 21,5 y finalizar el día 26 de incubación, se extendieron en promedio durante cuatro días, periodo mayor que el descrito en la literatura divulgativa probablemente porque en el presente estudio los huevos no estuvieron en contacto entre sí, lo que pudo limitar la sincronía en la eclosión. Los resultados de este estudio son útiles para conocer la distribución de la eclosión en las granjas cinegéticas de perdiz roja, posibilitando la mejora del manejo de los lotes de huevos en la nacedoraThe artificial incubation of the eggs is a key management phase for the feasibility of the red-legged partridge (Alectoris rufa) game farms. However, the length of the artificial incubation and the spreading pattern of the hatching have not been previously quantified in this species. To this end, four trials of artificial incubation of eggs from three red-legged partridge game farms located in southern Spain were analised. The trials included a wide range of variability with regard to management of breeders and incubation process. The average length of the incubation period was 23.4 days, with differences among trials (P = 0,004), showing a modal value of 23 days. Most of the chicks (percentile 95) hatched before 24.5 days of incubation. The distribution of the hatch was leptokurtic and showed positive asymmetry, fitting with the hatching pattern of the precocial species. The hatching, that can start on day 21.5 and finish on day 26 of incubation, were spread over four days on average. This period was longer than that described in the informative literature, probably because in the present study the eggs were not in contact with each other, which could have limited the hatching synchrony. The results of the present study are useful to understand the distribution of hatching in the red-legged game farms, enabling improved management of the batches of eggs in the hatchery

Optimal network topologies for local search with congestion

The problem of searchability in decentralized complex networks is of great importance in computer science, economy and sociology. We present a formalism that is able to cope simultaneously with the problem of search and the congestion effects that arise when parallel searches are performed, and obtain expressions for the average search cost--written in terms of the search algorithm and the topological properties of the network--both in presence and abscence of congestion. This formalism is used to obtain optimal network structures for a system using a local search algorithm. It is found that only two classes of networks can be optimal: star-like configurations, when the number of parallel searches is small, and homogeneous-isotropic configurations, when the number of parallel searches is large.Comment: 4 pages. Final version accepted in PR

Incorporation of europium into gan nanowires by ion implantation

Rare earth (RE)-doped GaN nanowires (NWs), combining the well-defined and controllable optical emission lines of trivalent RE ions with the high crystalline quality, versatility, and small dimension of the NW host, are promising building blocks for future nanoscale devices in optoelectronics and quantum technologies. Europium doping of GaN NWs was performed by ion implantation, and structural and optical properties were assessed in comparison to thin film reference samples. Despite some surface degradation for high implantation fluences, the NW core remains of high crystalline quality with lower concentrations of extended defects than observed in ion-implanted thin films. Strain introduced by implantation defects is efficiently relaxed in NWs and the measured deformation stays much below that in thin films implanted in the same conditions. Optical activation is achieved for all samples after annealing, and while optical centers are similar in all samples, Eu^3+ emission from NW samples is shown to be less affected by residual implantation damage than for the case of thin films. The incorporation of Eu in GaN NWs was further investigated by nano-cathodoluminescence and X-ray absorption spectroscopy (XAS). Maps of the Eu-emission intensity within a single NW agree well with the Eu-distribution predicted by Monte Carlo simulations, suggesting that no pronounced Eu-diffusion takes place. XAS shows that 70-80% of Eu is found in the 3+ charge state while 20-30% is 2+ attributed to residual implantation defects. A similar local environment was found for Eu in NWs and thin films: for low fluences, Eu is mainly incorporated on substitutional Ga-sites, while for high fluences XAS points at the formation of a local EuN-like next neighbor structure. The results reveal the high potential of ion implantation as a processing tool at the nanoscale

Synthesis and Biological Evaluation As Microtubule-Active Agents of Several Tetrahydrofuran and Spiroacetal Derivatives

The stereoselective preparation of several molecules containing structural fragments of the tetrahydrofuran and spiroacetal type is described. Their degree of cytotoxicity and their interactions with tubulin have been investigated. It has been confirmed that the tetrahydrofuran derivatives are cytotoxic but, in contrast to previous reports, it has been found that the cytoxicity is not due to interactions with the microtubule network. Furthermore, and also in contrast to a previous report on closely related compounds, the spiroacetal derivatives do show interactions with tubulin, even though the precise mechanism and the binding site still remain to be established

Structural Determinants of the Dictyostatin Chemotype for Tubulin Binding Affinity and Antitumor Activity Against Taxane- and Epothilone-Resistant Cancer Cells

A combined biochemical, structural, and cell biology characterization of dictyostatin is described, which enables an improved understanding of the structural determinants responsible for the high-affinity binding of this anticancer agent to the taxane site in microtubules (MTs). The study reveals that this macrolide is highly optimized for MT binding and that only a few of the structural modifications featured in a library of synthetic analogues resulted in small gains in binding affinity. The high efficiency of the dictyostatin chemotype in overcoming various kinds of clinically relevant resistance mechanisms highlights its potential for therapeutic development for the treatment of drug-resistant tumors. A structural explanation is advanced to account for the synergy observed between dictyostatin and taxanes on the basis of their differential effects on the MT lattice. The X-ray crystal structure of a tubulin−dictyostatin complex and additional molecular modeling have allowed the rationalization of the structure−activity relationships for a set of synthetic dictyostatin analogues, including the highly active hybrid 12 with discodermolide. Altogether, the work reported here is anticipated to facilitate the improved design and synthesis of more efficacious dictyostatin analogues and hybrids with other MT-stabilizing agents.We thank Peter T. Northcote for peloruside A, W.-S. Fang for Flutax-2, K. H. Altmann for epothilone D, Dr. Paraskevi Giannakakou (Weill Cornell Medical Center, New York) for the 1A9, PTX10, PTX22, and A8 cell lines, and Prof. Richard Ludueñ a (University of Texas) for the HeLa βIII-transfected cells. We thank Matadero INCOVA (Segovia) for the calf brains for tubulin purification. This work was supported in part by grants BIO2013-42984-R (J.F.D.) and SAF2012-39760-C02-02 (F.G.) from Ministerio de Economia y Competitividad, grant S2010/ ́ BMD-2457 BIPEDD2 from Comunidad Autonoma de Madrid ́ (F.G. and J.F.D.), and the Swiss National Science Foundation grants 310030B_138659 and 31003A_166608 (M.O.S.). The authors acknowledge networking contribution by the COST Action CM1407 “Challenging organic syntheses inspired by naturefrom natural products chemistry to drug discovery” and the COST action CM1470. I.P. thanks the EPSRC and AstraZeneca for funding, Dr. John Leonard (AstraZeneca) for useful discussions, Dr. Stuart Mickel (Novartis) for the provision of chemicals, and the EPSRC UK National Mass Spectrometry Facility at Swansea University for mass spectra

Oxidative stress and immunosenescence in spleen of obese mice can be reversed by 2-hydroxyoleic acid.

We aimed to investigate the effects of obesity on oxidative stress and leukocyte function in spleen of mice, and to assess whether supplementation with 2-hydroxyoleic acid (2-OHOA) or n-3 polyunsaturated fatty acids (PUFA) could reverse those effects. Female ICR/CD1 mice (8 weeks old, n = 24) received an obesogenic diet (22% fat for 4 weeks and 60% fat for 14 weeks). After 6 weeks, mice were split in three groups (n = 8/group): no supplementation, 2-OHOA supplementation (1500 mg kg(-1) ) and n-3 PUFA supplementation (EPA + DHA, 3000 mg kg(-1) diet). Eight mice were fed standard diet for the whole duration of the study (control group). At the end of the experiment, the following variables were assessed in spleens: levels of reduced (GSH) and oxidized (GSSG) glutathione, GSH/GSSG, xanthine oxidase (XO) activity, lipid peroxidation, lymphocyte chemotaxis, natural killer (NK) activity and mitogen (ConA and LPS)-induced lymphocyte proliferation. Obese animals presented higher GSSG levels (P = 0.003), GSSG/GSH ratio (P = 0.013), lipid peroxidation (P = 0.004), XO activity (P = 0.015) and lymphocyte chemotaxis (P < 0.001), and lower NK activity (P = 0.003) and proliferation in response to ConA (P < 0.001) than controls. 2-OHOA reversed totally or partially most of the changes (body weight, fat content, GSSG levels, GSH/GSSG, lipid peroxidation, chemotaxis and proliferation, all P < 0.05), while n-3 PUFA reversed the increase in XO activity (P = 0.032). In conclusion, 2-OHOA, and to a lesser extent n-3 PUFA, could ameliorate the oxidative stress and alteration of leukocyte function in spleen of obese mice. Our findings support a link between obesity and immunosenescence and suggest a potential therapeutic tool for obesity-related immune dysfunction. This article is protected by copyright. All rights reserved

Structural Determinants of the Dictyostatin Chemotype for Tubulin Binding Affinity and Antitumor Activity Against Taxane- and Epothilone-Resistant Cancer Cells

A combined biochemical, structural, and cell biology characterization of dictyostatin is described, which enables an improved understanding of the structural determinants responsible for the high-affinity binding of this anticancer agent to the taxane site in microtubules (MTs). The study reveals that this macrolide is highly optimized for MT binding and that only a few of the structural modifications featured in a library of synthetic analogues resulted in small gains in binding affinity. The high efficiency of the dictyostatin chemotype in overcoming various kinds of clinically relevant resistance mechanisms highlights its potential for therapeutic development for the treatment of drug-resistant tumors. A structural explanation is advanced to account for the synergy observed between dictyostatin and taxanes on the basis of their differential effects on the MT lattice. The X-ray crystal structure of a tubulin−dictyostatin complex and additional molecular modeling have allowed the rationalization of the structure−activity relationships for a set of synthetic dictyostatin analogues, including the highly active hybrid 12 with discodermolide. Altogether, the work reported here is anticipated to facilitate the improved design and synthesis of more efficacious dictyostatin analogues and hybrids with other MT-stabilizing agents.We thank Peter T. Northcote for peloruside A, W.-S. Fang for Flutax-2, K. H. Altmann for epothilone D, Dr. Paraskevi Giannakakou (Weill Cornell Medical Center, New York) for the 1A9, PTX10, PTX22, and A8 cell lines, and Prof. Richard Ludueñ a (University of Texas) for the HeLa βIII-transfected cells. We thank Matadero INCOVA (Segovia) for the calf brains for tubulin purification. This work was supported in part by grants BIO2013-42984-R (J.F.D.) and SAF2012-39760-C02-02 (F.G.) from Ministerio de Economia y Competitividad, grant S2010/ ́ BMD-2457 BIPEDD2 from Comunidad Autonoma de Madrid ́ (F.G. and J.F.D.), and the Swiss National Science Foundation grants 310030B_138659 and 31003A_166608 (M.O.S.). The authors acknowledge networking contribution by the COST Action CM1407 “Challenging organic syntheses inspired by naturefrom natural products chemistry to drug discovery” and the COST action CM1470. I.P. thanks the EPSRC and AstraZeneca for funding, Dr. John Leonard (AstraZeneca) for useful discussions, Dr. Stuart Mickel (Novartis) for the provision of chemicals, and the EPSRC UK National Mass Spectrometry Facility at Swansea University for mass spectra