RESUMO
Study of swirling flows in channels corresponding to the static approximation of flow channels of the heart and major vessels with a longitudinal-radial profile zR2 = const and a concave streamlined surface at the beginning of the longitudinal coordinate has been carried out. A comparative analysis of the flow structure in channel configurations zRN = const, where N = -1, 1, 2, 3, in the absence and presence of a concave surface was carried out. The numerical modeling was compared with the results of hydrodynamic experiments on the flow characteristics and the shape of the flow lines. The numerical model was used to determine the velocity structure, viscous friction losses, and shear stresses. Numerical modeling of steady-state flows for channels without a concave surface showed that in the channel zR2 = const there is a stable vortex flow structure with the lowest viscous friction losses. The presence of a concave surface of sufficient size significantly reduces viscous friction losses and shear stresses in both the steady state and pulsed modes.
Assuntos
Hemodinâmica , Modelos Cardiovasculares , Hemodinâmica/fisiologia , Aorta , Simulação por Computador , CoraçãoRESUMO
Common disadvantages of modern synthetic vascular prostheses are thrombogenicity and lack of biomechanical compatibility with the prothesized vessel. To elucidate the role of these factors in the prosthesis integration, prostheses specimens were made by the electrospinning from the known materials: polycaprolactone, polyurethane and a mixture of fluorine-containing synthetic rubber FKM-26 with fluoroplastic F-26. The germination of the prostheses was compared with standard e-PTFE prosthesis in the pigs infrarenal aorta. The elastic properties of prostheses were studied by elastometry under the physiological range of loads. The thrombogenicity of the materials was determined by the number of platelets adhered to material surface exposed to native blood. The patency of the prostheses was checked by aortography. The germination of prostheses was assessed in the histological examination. It was shown that, with this set of materials, biomechanical compatibility turned out to be a more important factor of integration than the material thrombogenicity.
Assuntos
Prótese VascularRESUMO
This article was designed to report the results of the comprehensive (historical-archival, forensic anthropological, and molecular-genetic) investigation into the holy relics of the righteous martyr Anastasiya of Uglich. The well-reasoned expert conclusion contains the scientifically sound data on the prescription of the martyr's corpse burial, age group and sexual identity of the relics, specific anthropological features of the skeleton, torture instruments, and the immediate cause of death. Taken together, the data thus obtained give evidence that the relics actually belong to one of the well-known saints of the Russian orthodox church.
Assuntos
Antropologia Forense , Santos , Sepultamento , Cadáver , Causas de Morte , Humanos , EsqueletoRESUMO
OBJECTIVE: comparative assessment of informativity of parameters of arterial wall stiï¬ness - the cardio-ankle vascular index (CAVI), the augmentation index (AI) - for solution of problems of screening patients being under threat of realization of complex impact of metabolic syndrome (MS) and elevated vessel wall stiï¬ness, both creators and markers of high risk of severe cardiovascular complications. MATERIALS AND METHODS: We examined mining industry employees (n=206) with cardiac risk factors (arterial hypertension, abdominal obesity, and smoking). Comparative group comprised 75 employees of the same enterprise without above-mentioned risk factors. Studies of arterial wall stiï¬ness included determination of CAVI and AI. The sensitivity, specifcity and accuracy of the screening method were calculated. RESULTS: CAVI and AI parameters had diï¬erent sensitivity, specifcity and accuracy for identifying patients at risk of cardiovascular complications. AI was 2 times more sensitive than CAVI during examination of patients with only clinical and anamnestic cardiovascular risk markers and patients with clinical-anamnestic and laboratory risk markers. Specifcity of AI was lower than specifcity of CAVI and atained only 34.4% in patients with clinical-anamnestic and laboratory risk factors. At the same time, specifcity of CAVI in these patients reached 86.2%. Accuracy of AI for screening study was 1.4 times higher than that of CAVI in patients with only clinical-anamnestic risk markers, and 1.6 times higher in patients with both clinical-anamnestic and laboratory risk markers. Moreover, after comparing patient groups with individually high and normal CAVI and AI, we found the diï¬erences in metabolic laboratory risk factors (glucose, total cholesterol, triglycerides and the Atherogenic Index) only for AI. CONCLUSION: Parameters of arterial stiï¬ness have diï¬erent informative value for screening of patients with clinical-anamnestic or laboratory risk factors. AI compared with CAVI is 2 times more sensitive and 1.6 times more accurate but has lower specifcity for risk factor screening among patients being under threat of realization of complex impact of MS and elevated vessel wall stiï¬ness.
Assuntos
Artérias , Hipertensão , Rigidez Vascular , Pressão Sanguínea , Humanos , Fatores de RiscoRESUMO
Myocardium revascularization in coronary heart disease patients is one of the most important treatment modalities. Considerable improvement of somatic state after surgery for IHD is seen in 82-83% of patients in average, whereas only hardly more than a half return to occupational activity without decrease in preoperative level of qualification and performance. In occupational therapy and industrial medicine clinic with FBSI <
Assuntos
Ponte de Artéria Coronária , Doença das Coronárias , Ocupações em Saúde/normas , Estilo de Vida Saudável/fisiologia , Retorno ao Trabalho/estatística & dados numéricos , Adulto , Fatores Etários , Idoso , Ponte de Artéria Coronária/reabilitação , Ponte de Artéria Coronária/estatística & dados numéricos , Doença das Coronárias/epidemiologia , Doença das Coronárias/psicologia , Doença das Coronárias/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Serviços Preventivos de Saúde/métodos , Serviços Preventivos de Saúde/organização & administração , Fatores de Risco , Gestão de Riscos/métodos , Federação Russa/epidemiologia , Fatores SexuaisRESUMO
Workers of titanium and magnesium production, under occupational exposure to complex of chemical (chlorine, hydrochloride, sulfur dioxide) and physical factors (industrial noise, work hardiness), have arterial hypertension as occupationally related disease, when length of service over 15 years (EF = 71,5%), and nasopharyngitis for length of service over 10 years (EF = 65%). Arterial hypertension risk is mostly associated with increased industrial noise level (F = 1621; R2 0.95; p < 0,001; noise 70,1 dB). Mathematic modelling of nasopharyngitis development probability demonstrated dependence of concentration of chlorine, hydrochloride, sulfur dioxide, chlorine and hydrochloride combination (F = 37-281; R2 = 0,37-0,73; p < 0.001; chlorine 0,63 mg/m3). Complex of parameters (leucocytosis, eosinophilia, increased IgA level), activated cellular immunity (increased CD 16+56+, CD3+CD25+) and absolute phagocytosis characterized nonspecific inflammatory reaction, immunity tension as a response to a complex of chemical factors of titanium and magnesium production. Markers of endoihelial dysfunction and cardiovascular risk (uric acid, VEGF, homocystein, LDLP) and stress marker (cortisol) demonstrate potential effect of occupational factors on vascular wall, metabolic processes and central nervous system, with involvement of Assuntos
Poluentes Ocupacionais do Ar/análise
, Hipertensão
, Metalurgia
, Ruído Ocupacional/efeitos adversos
, Doenças Profissionais
, Carga de Trabalho/normas
, Adulto
, Estudos de Casos e Controles
, Previsões
, Humanos
, Hipertensão/epidemiologia
, Hipertensão/etiologia
, Modelos Teóricos
, Doenças Profissionais/epidemiologia
, Doenças Profissionais/etiologia
, Risco
, Federação Russa
RESUMO
A hybridological study of biotypes of species close to Elymus caninus: E. prokudinii, E. viridiglumis, E. goloskokovii, as well as a number of morphologically deviant biotypes in Russia and Kazakhstan, was carried out. The objectives were to study the levels of reproductive relationships and the degree of integration of the species E. goloskokovii, E. prokudinii, and E. viridiglumis into the E. caninus complex. Our estimates of the seed fertility of natural parental biotypes were within 60-90 %. Among the combinations of crossing in F1, the highest seed setting was found in the hybrids formed by parental pairs from close habitats, regardless of the taxonomic rank of biotypes. The highest fertility values (55.6 and 46.1 %) were found in combinations involving E. caninus, E. viridiglumis and E. goloskokovii. It has been concluded that the biotypes of these species included in sexual hybridization form a single recombination gene pool, within which slight differences in reproductive compatibility are observed. The nature of the inheritance of the diagnostic features of lemmas "presence of trichomes" and "length of awns", according to the digenic and monogenic type, respectively, is shown. The high seed fertility of the created hybrids and the presence of intermediate forms in the F2 generation according to distinctive features indicate the possibility of interspecific introgression when species grow together in natural populations. Thus, the assessment of the inheritance of diagnostic characters makes it possible to classify E. goloskokovii, E. prokudinii, and E. viridiglumis as intraspecific taxa of E. caninus s. l. Data were obtained on the morphological and reproductive properties of interspecific hybrids with the participation of the species E. mutabilis as a possible donor in the speciation of taxa close to E. caninus. In cross combinations of E. caninus × E. mutabilis and E. mutabilis × E. caninus, lower values of seed fertility of hybrids in the F1 and F2 generations were noted compared to hybrids between the species E. caninus, E. goloskokovii, E. prokudinii and E. viridiglumis. Nevertheless, on the basis of chorological and morphological criteria, we concluded that E. caninus and E. mutabilis are independent species.
RESUMO
For the first time the emission of neutron bursts in the process of high-voltage discharge in air was observed. Experiments were carried out at an average electric field strength of â¼1 MV·m(-1) and discharge current of â¼10 kA. Two independent methods (CR-39 track detectors and plastic scintillation detectors) registered neutrons within the range from thermal energies up to energies above 10 MeV and with an average flux density of â³10(6) cm(-2) per shot inside the discharge zone. Neutron generation occurs at the initial phase of the discharge and correlates with x-ray generation. The data obtained allow us to assume that during the discharge fast neutrons are mainly produced.
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AIM: To study the parameters of the structural and functional state of the myocardium in patients with hypertension, to determine their prognostic value on the risk of atrial fibrillation (AF). PATIENTS AND METHODS: The study involved 72 people: patients with hypertension and AF, with isolated hypertension and apparently healthy individuals. All of them performed echocardiography, blood pressure monitoring and monitoring of cardiogram. RESULTS: The dilatation of left atrial was founded: patients with the atrial fibrillation on the background of hypertension observed the most pronounced changes in the left atrial. In patients with hypertension without arrhythmias and in combination with atrial fibrillation severe left ventricular hypertrophy was observed. Left ventricle systolic function in groups has been stored but in patients with atrial fibrillation on the background of hypertension was significantly lower. The risk of atrial fibrillation in patients with hypertension prognostic value are the only values of the age, the volume index of the left atrial to the body surface area and left ventricular ejection fraction. CONCLUSIONS: The risk of AF in hypertension occurs over the age of 55 and each subsequent year increases it in 1,2 times, it increases with an index value of the left atrial to the body surface over 29 ml/m2 and with a decrease in left ventricular ejection fraction less than 58%.
Assuntos
Fibrilação Atrial/diagnóstico , Átrios do Coração/diagnóstico por imagem , Hipertensão/complicações , Função Ventricular Esquerda , Idoso , Fibrilação Atrial/etiologia , Fibrilação Atrial/fisiopatologia , Pressão Sanguínea , Ecocardiografia , Eletrocardiografia , Feminino , Seguimentos , Átrios do Coração/fisiopatologia , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Volume SistólicoRESUMO
PURPOSE: to evaluate the state of the structure and function of the arterial wall in patients with chronic heart failure (CHF) of ischemic etiology in combination with persistent atrial fibrillation (AF) AF and the dynamics of their changes during therapy with omega-3 polyunsaturated fatty acids (omega-3 PUFA). MATERIAL AND METHODS: in the first phase in order to identify characteristics of a CCF and the restructuring of the arterial wall 120 patients with coronary artery disease and chronic heart failure II-III functional class (FC) were included in the study, then were divided into two equal groups according to the presence of persistent AF. In the second phase patients with CHF and persistent AF were randomized into 2 groups of 30 people to determine the vasoprotective effect of omega-3 fatty acids compared with the standard treatment of CHF. The duration of treatment was 6 months. To assess the conductive and damping functions of arteries comprehensive sfigmopletizmografiyu was carried out. To assess the state of the arteries collagen matrix we determined the level of tissue inhibitor of matrix metalloproteinases type I (TIMP-1) by enzyme immunoassay. RESULTS: in patients with chronic heart failure of ischemic etiology in combination with persistent AF we revealed more severe functional impairment of the arterial wall, characterized by an increase in pulse wave velocity in carotid-femoral segment (p=0.037), the aorta (p<0.001), indexes CAVI1 (p less or equal 0.001) and augmentation (p=0.049; p<0.001) in the absence of differences in the group of patients with heart failure and sinus rhythm in terms of structural changes in collagen matrix- TIMP-1. The progress of CHF against the background persistent AF was characterized by higher levels of atrial natriuretic peptide with prevalence of diastolic dysfunction, while the more frequent co-morbidities (hypertension, diabetes mellitus type 2, stroke/transient ischemic attack), and risk factors. Inclusion in the treatment of patients with chronic heart failure of ischemic etiology and persistent AF omega-3 fatty acids provides reliable vasoprotective effect by suppressing the abnormal collagen formation on the dynamics of TIMP-1 (p<0.001) and improving the elastic properties of the arterial wall to the dynamics of high-speed data and indexed blood flow the arterial tree (p<0.001), with the exception of ankle-brachial indexes. CONCLUSION: structurally functional remodeling of the arterial wall in patients with chronic heart failure of ischemic etiology and persistent AF has a definite pattern of forming. Omega-3 fatty acids have a vasoprotective effect, providing improving elastic properties of the arteries by preventing fibrosis.
Assuntos
Artérias , Fibrilação Atrial , Ácidos Graxos Ômega-3/administração & dosagem , Insuficiência Cardíaca , Isquemia Miocárdica/complicações , Resistência Vascular/efeitos dos fármacos , Adulto , Artérias/efeitos dos fármacos , Artérias/fisiopatologia , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/etiologia , Fibrilação Atrial/fisiopatologia , Fármacos Cardiovasculares/uso terapêutico , Técnicas de Diagnóstico Cardiovascular , Monitoramento de Medicamentos/métodos , Feminino , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Substâncias Protetoras/administração & dosagem , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
The paper presents a concise literature review on the concomitant course of the most common nosological entities in the population, such as arterial hypertension (AH) and acid-dependent diseases (ADD). Data on the prevalence, commonness of etiological and pathogenetic factors, the specific features of a clinical course, and diagnostic difficulties are analyzed in persons with AH associated with ulcerative and gastrointestinal reflux diseases. The causes and consequences of these nosological entities are shown; their clinical, morphological, and hemodynamic features are covered. The results of investigations characterizing the specific features of autonomic regulation, diurnal blood pressure variations, and the central hemodynamics in the comorbidity of the diseases in question are given. The rational antihypertensive therapy of AH concurrent with ADD is presented in terms of their impact on gastrointestinal tract disease.
Assuntos
Anti-Hipertensivos/uso terapêutico , Gastroenteropatias/epidemiologia , Hipertensão/epidemiologia , Pressão Sanguínea , Comorbidade , Refluxo Gastroesofágico/epidemiologia , Refluxo Gastroesofágico/fisiopatologia , Gastroenteropatias/fisiopatologia , Humanos , Hipertensão/tratamento farmacológico , PrevalênciaRESUMO
Arrhythmogenic role of proinflammatory cytokines is still unclear despite of wide discussion on inflammatory arrhythmogenic mechanisms. The main goal of study was to compare levels of tumor necrosis factor a, interleukin 6 and interleukin 4 in hypertensive patients with and without ventricular rhythm disturbances. The study included 100 cases, 50 of those had ventricular arrhythmias. Levels of tumor necrosis factor a, interleukin 6 and interleukin 4 were studied. Possible connections of above mentioned biomarkers with ventricular arrhythmias, blood pressure, echocardiography left ventricle data were evaluated. Higher level of biomarkers was associated with presence of ventricular arrhythmias; higher rate of ventricular extrasystoles was accompanied with insignificantly lower biomarker level.
Assuntos
Biomarcadores/sangue , Hipertensão/complicações , Inflamação/sangue , Taquicardia Ventricular/etiologia , Adolescente , Adulto , Pressão Sanguínea , Proteína C-Reativa/metabolismo , Citocinas/sangue , Feminino , Seguimentos , Frequência Cardíaca , Humanos , Hipertensão/sangue , Hipertensão/fisiopatologia , Inflamação/complicações , Masculino , Pessoa de Meia-Idade , Taquicardia Ventricular/sangue , Taquicardia Ventricular/fisiopatologia , Adulto JovemRESUMO
The results of study of the subaqueous acoustic signaling of bottlenose dolphins (Tursiopsis truncatus) in a dolphinarium are shown. Individual patterns of whistling signals of four individuals were described and analyzed. To determine which animal produced the sound, the method of "relative isolation" was used. It was found that the pattern included whistles specific for a particular individual ("signature whistles"). The percentage of these whistles in the patterns varied considerably among individuals. The signatures had variable frequency and duration. The phenomenon of "imitation" was typical for animals at higher positions in the hierarchy: generating "signatures" specific for other individuals. Besides the signatures, variable signals and whistles with simple frequency contours were found in the patterns.
Assuntos
Golfinho Nariz-de-Garrafa/fisiologia , Vocalização Animal/fisiologia , Animais , Feminino , MasculinoRESUMO
Four types of ionic liquids (ILs) of [X]TFSI ([X]+ is a cation such as 1-butyl-3-methylimidazolium BMIm+, 1-butyl-1-methylpyrrolidinium BMPyrr+, 1-butyl-1-methylpiperidinium BMPip+ and methyltrioctylammonium MOc3Am+ and TFSI- is the bis(trifluoromethylsulfonyl)imide anion) were confined in halloysite nanoclay (Hal) at an excess ionic liquid concentration (IL : Hal â¼55 : 45 wt%) and studied by X-ray diffraction, TG, DSC analysis and FTIR spectroscopy. It was found that the physicochemical properties of ILs trapped by halloysite at maximum loading are similar to those of bulk ILs and change depending on the cation type and size. The cold crystallization temperature (T cc) and melting point (T m) of the crystalline mesophase in confined BMIm+ and BMPyrr+ ionic liquids are higher than in the bulk ones, while in the amorphous BMPyrr+ mesophase, the T cc and T m values decrease by 9.7 and 14.2 °C, respectively. Confined BMPip+ and MOc3Am+ only have the glass transition temperature (T g), which increases by 1.5 and 8.0 °C, respectively, compared to bulk ILs. The onset decomposition temperature (T d) decreases by 106.5, 40.7, 19.0 and 7.7 °C in BMIm+, BMPip+, BMPyrr+ and MOc3Am+, respectively. The changes in the properties are explained by the cation and anion interaction with halloysite, as well as by the transformation of the ionic liquid structure. It is found that in this case the amount of the TFSI- anion trans-conformer increases in the following order: BMIm+ > BMPyrr+ â¼ BMPip+ >> MOc3Am+.
RESUMO
This paper proposes a new approach to the quantitative analysis of the hydrodynamic structure of a blood flow in the flow channel running from the left atrium to the end of the aorta. This approach is based on the concept of the structural organization of tornado-like swirling jets in channels with a given geometric configuration. Considering the large amount of experimental data in our possession, it was shown that along the entire length of the flow channel, conditions exist for the generation and maintenance of a swirling structure of the jet throughout the entire cardiac cycle. This study has given rise to a new direction in research in fundamental physiology and medicine, which is of great practical importance for diagnosing and treating circulatory disorders accompanied by changes in the geometric configuration and biomechanical characteristics of the heart and great vessels.
RESUMO
The genus Elymus L., together with wheat, rye, and barley, belongs to the tribe Triticeae. Apart from its economic value, this tribe is characterized by abundance of polyploid taxa formed in the course of remote hybridization. Single-copy nuclear genes are convenient markers for identification of source genomes incorporated into polyploids. In the present work, a CAPS-marker is developed to distinguish basic St, H, and Y genomes comprising polyploid genomes of Asiatic species of the genus Elymus. The test is based on electrophoretic analysis of restriction patterns of a PCR-amplified fragment of the gene coding for beta-amylase. There are about 50 Elymus species in Russia, and most of them are supposed to possess one of three haplome combinations, StH, StY and StHY. Boreal StH-genomic species endemic for Russia are the least studied. On the basis of nucleotide sequences from public databases, TaqI restrictase was selected, as it produced patterns of restriction fragments specific for St, H, and Y haplomes easily recognizable in agarose gel. A sample of 68 accessions belonging to 32 species was analyzed. In 15 species, the earlier known genomic constitutions were confirmed, but in E. kamoji this assay failed to reveal the presence of H genome. This unusual H genome was suggested to originate from a different Hordeum species. In 16 species, genomic constitutions were identified for the first time. Fifteen accessions from Asian Russia possessed the genomic constitution StStHH, and E. amurensis, phylogenetically close to the StY-genomic species E. ciliaris, had the genomic constitution StStYY. It is inferred that the center of species diversity of the StH-genomic group is shifted to the north as compared to the center of origin of StY-genomic species, confined to China. Key words: Elymus; taxonomy; allopolyploids; genome constitution; CAPS markers.
RESUMO
The influenc of cholesterol on the formation of the mitochondrial cyclosporin A (CsA)-insensitive palmitate/Ca(2+)-activated pore has been studied. It has been established that increasing the cholesterol level in mitochondrial membranes results in an increase in the of rate of mitochondrial swelling induced by palmitic acid (> or = 20 microM) and Ca2+ (30 microM). This effect is not related to changes in the functional activity of organelles since cholesterol did not influence the mitochondrial respiration in different metabolic states. At the same time, it was shown that the palmitate/Ca(2+)-induced permeabilization of cholesterol-containing azolectin liposomes was Stronger than that of azolectin liposomes. It was found that, in the liposomal membrane, the Ca(2+)-induced phase separation of palmitic acid into distinct membrane domains takes place. The presence of cholesterol in membranes increases the extent of segregation.
Assuntos
Cálcio/metabolismo , Colesterol/fisiologia , Mitocôndrias Hepáticas/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Ácido Palmítico/metabolismo , Lipossomas Unilamelares/química , Animais , Colesterol/química , Colesterol/farmacologia , Técnicas In Vitro , Membranas Intracelulares/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Dilatação Mitocondrial , Permeabilidade , Fosfatidilcolinas/química , RatosRESUMO
Titanium dioxide nanoparticles, obtained using the sol-gel method and modified with organic solvents, such as acetone, acetonitrile, benzene, diethyl ether, dimethyl sulfoxide, toluene, and chloroform, were used as the filler of polydimethylsiloxane-based electrorheological fluids. The effect of electric field strength on the shear stress and yield stress of electrorheological fluids was investigated, as well as the spectra of their dielectric relaxation in the frequency range from 25 to 106 Hz. Modification of titanium dioxide by polar molecules was found to enhance the electrorheological effect, as compared with unmodified TiO2, in accordance with the widely accepted concept of polar molecule dominated electrorheological effect (PM-ER). The most unexpected result of this study was an increase in the electrorheological effect during the application of nonpolar solvents with zero or near-zero dipole moments as the modifiers. It is suggested that nonpolar solvents, besides providing additional polarization effects at the filler particles interface, alter the internal pressure in the gaps between the particles. As a result, the filler particles are attracted to one another, leading to an increase in their aggregation and the formation of a network of bonds between the particles through liquid bridge contacts. Such changes in the electrorheological fluid structure result in a significant increase in the mechanical strength of the structures that arise when an electric field is applied, and an increase in the observed electrorheological effect in comparison with the unmodified titanium dioxide.
RESUMO
Artificial sexual hybrids between Elymus caninus (L.) L. and E. fibrosus (Schrebk) Tzvel. were experimentally examined in generations F1-F5. The possibility of genetic introgression between these species was shown. Morphologically, the hybrid plants can be assigned to either of the parental species or to variety E. caninus var. muticus (Holmb.) Karlsson. Some traits (spike density, leaf blade width, leaf blade pubescence, awns of lemmas) exhibited considerable variation. Polypeptide spectra of endosperm proteins were characterized in the initial parental biotypes and the hybrid progeny, using a gel-buffer SDS electrophoresis system. It was suggested that successful interspecies hybridization requires backcrosses or normalizing crosses. The possibility of sexual genetic exchange enables to utilize the gene pools of the two species to transfer the required traits in selection forage forms.
Assuntos
Quimera/genética , Elymus/genética , Hibridização Genética , Modelos Genéticos , Poaceae/genética , Quimera/anatomia & histologia , Cruzamentos Genéticos , Eletroforese em Gel de Poliacrilamida , Elymus/anatomia & histologia , Proteínas de Plantas/análise , Poaceae/anatomia & histologiaRESUMO
The dynamics of structural changes in pea chloroplasts in the presence of 25-50 microM dibucaine or tetracaine has been examined using electron microscopy. The light-induced uptake of anesthetic cations by thylakoids is attended by the appearance of local fusions of stroma-exposed thylakoid membranes. The first membrane protrusions and interthylakoid contacts are observed after 4 s illumination and they become numerous by 10 s. As a result, a network of anastomoses is formed which is maintained during at least 10 min. These effects are reversible in the dark and can be reproduced several times. The formation of membrane fusions is inhibited by the addition of protonophore. It is supposed that the energy-dependent uptake of protonated anesthetics by thylakoids leads to an increase in positive surface charge and thus a lateral pressure on the inner side of the thylakoid membrane. The appearance of membrane protrusions (crinkles) having the positive curvature of their inner surface may be considered as a way of compensating for lateral pressure. Presumably, anastomoses result from the fusion of crinkles to adjacent thylakoids.