RESUMEN
In the present work, the potential for the enhancement of the adaptive capacity of microbe-plant systems (MPSs) through the integration of the symbiosis partners' genomes is considered on the example of different types of symbiotic relationships. The accumulated data on the genetic control of interactions for both the plant and microbe, which are discussed in the paper with respect to signaling genes, suggest that it is the complementarity of genetic determinants that underlies the successful formation of MPSs. A eukaryotic genome with limited information content, which is stable throughout a generation, is complemented by a virtually unlimited prokaryotic metagenome. The microsymbiont's ability to adapt to different living conditions is based on the restructuring of the accessory genome by different mechanisms, which are likely to be activated under the influence of plants, although the details of such a regulation remain unknown. Features of the genetic control of the interaction, particularly its universal character for different symbionts, allow us to formulate a principle of genome-complementarity with respect to interacting organisms and consider it an important factor, an adaptation that enhances the abilities of M PSs for their sustainable development in natural ecosystems and for high plant productivity in agrocenoses.
Asunto(s)
Adaptación Fisiológica/genética , Genes de Plantas/fisiología , Metagenoma/fisiología , Plantas/genética , Simbiosis/genéticaRESUMEN
The efficiency of different drugs for sedation was studied in 51 patients after large abdominal operations complicated by postoperative delirium. Diagnosis of postoperative delirium was established according to CAM-ICU criteria. Dexmedetomidine has demonstrated significantly decreased duration of delirium and hospital stay in intensive care unit in comparison with haloperidol. Besides, patients which received dexmedetomidine preserved opportunity for verbal contact. Also these patients interacted better with department's stuff.
Asunto(s)
Cavidad Abdominal/cirugía , Delirio , Dexmedetomidina , Complicaciones Posoperatorias , Procedimientos Quirúrgicos Operativos/efectos adversos , Adulto , Anciano , Delirio/diagnóstico , Delirio/tratamiento farmacológico , Delirio/etiología , Dexmedetomidina/administración & dosificación , Dexmedetomidina/efectos adversos , Femenino , Humanos , Hipnóticos y Sedantes/administración & dosificación , Hipnóticos y Sedantes/efectos adversos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/tratamiento farmacológico , Resultado del TratamientoRESUMEN
Based on currently available data, the energy transfer efficiency in the successive photophysical and photochemical stages has been analyzed for purple bacteria. This analysis covers the stages starting from migration of the light-induced electronic excitations from the bulk antenna pigments to the reaction centers up to irreversible stage of the electron transport along the transmembrane chain of cofactors-carriers. Some natural factors are revealed that significantly increase the rates of efficient processes in these stages. The influence on their efficiency by the "bottleneck" in the energy migration chain is established. The overall quantum yield of photosynthesis in these stages is determined.
Asunto(s)
Fotosíntesis/fisiología , Proteobacteria/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Transferencia de Energía , Cinética , Modelos Moleculares , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Teoría CuánticaRESUMEN
The atomic structures of photosynthetic reaction centers of two species of purple bacteria and two photosystems 2 of cyanobacteria were resolved in the late last century. In this work I put forward the idea that of the huge body of data available thus far, only three structural factors are responsible for the unique function of conversion of physical energy of electronic excitation into electrochemical energy of separated opposite charges in reaction centers at least in purple bacteria and, perhaps, in other photosynthetic organisms.
Asunto(s)
Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Proteínas del Complejo del Centro de Reacción Fotosintética/química , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Bacterioclorofilas/química , Bacterioclorofilas/metabolismo , Transporte de Electrón , Cinética , Modelos Biológicos , Fotosíntesis , Rhodopseudomonas/química , Rhodopseudomonas/metabolismoRESUMEN
The contradiction between two groups of experimental data, which fails to be resolved within the framework of the widely accepted model of excitation migration and trapping (at least in case of purple bacteria), is discussed in the introduction to this review. Three directions of studies intended to resolve this conflict are reviewed in the three further sections: II. Exciton models; III. Water-polarization (water-latch) mechanism of excitation trapping; IV. Quantum-mechanical models. The maximum efficiency of these models in resolving the contradiction mentioned above was assessed. The advantages and disadvantages of the mechanisms described in sections II, III, and IV are discussed in the last section of this review. It is concluded that none of these mechanisms taken alone is able to solve this problem. Therefore, the fundamental problem of the primary excitation conversion in reaction centers remains unsolved and requires additional experimental research.
Asunto(s)
Modelos Biológicos , Proteínas del Complejo del Centro de Reacción Fotosintética/metabolismo , Proteobacteria/metabolismo , Transferencia de Energía , Cinética , Fotoquímica , Teoría Cuántica , Agua/químicaRESUMEN
A locus for binding a mobile water molecule was searched for in the immediate vicinity of the special pair in the reaction center. Using the PROTEUS PC-program (a part of the GRASP package) atomic structures of the reaction centers were analyzed in purple bacteria Rhodopseudomonas viridis and Rhodobacter sphaeroides. In both structures the loci for binding mobile water molecules were found at the distance of about 4.5 A from the middle of the special pair in the reaction center. The reorientation of a hydrogen atom of this water molecule in the electric field of the excited special pair required energy of no less than 40 MeV that corresponded to predictions of the water-polarization model of trapping of electron excitation which was developed by M. V. Fok and one of the authors of this article.