25 research outputs found
Inactivation of the geranylgeranyl reductase (ChlP) gene in the cyanobacterium Synechocystis sp. PCC 6803
AbstractGeranylgeranyl reductase catalyses the reduction of geranylgeranyl pyrophosphate to phytyl pyrophosphate required for synthesis of chlorophylls, phylloquinone and tocopherols. The gene chlP (ORF sll1091) encoding the enzyme has been inactivated in the cyanobacterium Synechocystis sp. PCC 6803. The resulting ΞchlP mutant accumulates exclusively geranylgeranylated chlorophyll a instead of its phytylated analogue as well as low amounts of Ξ±-tocotrienol instead of Ξ±-tocopherol. Whereas the contents of chlorophyll and total carotenoids are decreased, abundance of phycobilisomes is increased in ΞchlP cells. The mutant assembles functional photosystems I and II as judged from 77 K fluorescence and electron transport measurements. However, the mutant is unable to grow photoautotrophically due to instability and rapid degradation of the photosystems in the absence of added glucose. We suggest that instability of the photosystems in ΞchlP is directly related to accumulation of geranylgeranylated chlorophyll a. Increased rigidity of the chlorophyll isoprenoid tail moiety due to three additional CC bonds is the likely cause of photooxidative stress and reduced stability of photosynthetic pigmentβprotein complexes assembled with geranylgeranylated chlorophyll a in the ΞchlP mutant
Π€ΡΠ°ΠΊΡΠΈΠΎΠ½Π½Π°Ρ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΡ Π±Π΅Π»ΠΎΠ³ΠΎ ΠΈ ΡΠ΅ΡΠΎΠ³ΠΎ Π²Π΅ΡΠ΅ΡΡΠ²Π° Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π° Π² ΠΎΡΡΡΠΎΠΌ ΠΏΠ΅ΡΠΈΠΎΠ΄Π΅ ΠΈΡΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈΠ½ΡΡΠ»ΡΡΠ° ΠΊΠ°ΠΊ ΠΌΠ°ΡΠΊΠ΅Ρ Π½Π΅Π²ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ, ΠΊΠΎΠ³Π½ΠΈΡΠΈΠ²Π½ΠΎΠ³ΠΎ ΠΈ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΡΠ°ΡΡΡΠ°
Aim. To study the fractional anisotropy of white and gray brain matter and its associations with clinical and instrumental data in acute ischemic stroke. Materials and methods. The parameters of fractional anisotropy of 10 areas of white and gray brain matter were analyzed in 30 acute ischemic stroke patients by diffusion-tensor imaging. The neurological (NIHSS), cognitive (MMSE), functional (Rivermead Mobility Index and Modified Rankin Scale) and some laboratory and instrumental data were assessed. Results. The fraction anisotropy was analyzed on the side of lesion and symmetrically. The decline of anisotropy was revealed in posterior limb of internal capsule on the side of stroke independently of the lesion location. Also the interactions between fraction anisotropy and stroke severity, global cognitive status and duration of hospital treatment were found. Conclusion. The obtained data may suggest that in acute period of stroke the neurodegeneration and neuroreparational ready start. It appears the changes of white and gray matter integrity. According to the concept βheart-vessels-brainβ we received the data indicating the significance of vascular risk factors which lead to hypoperfusion and hypoxia in the development of microstructural changes. Some parameters of fractional anisotropy may predict clinical and functional outcome on discharge.Π¦Π΅Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ: ΠΎΡΠ΅Π½ΠΈΡΡ ΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΡΡ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΡ Π±Π΅Π»ΠΎΠ³ΠΎ ΠΈ ΡΠ΅ΡΠΎΠ³ΠΎ Π²Π΅ΡΠ΅ΡΡΠ²Π° Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π° ΠΈ Π΅Π΅ ΡΠ²ΡΠ·Ρ Ρ ΠΊΠ»ΠΈΠ½ΠΈΠΊΠΎ-ΠΈΠ½ΡΡΡΡΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ Π² ΠΎΡΡΡΠΎΠΌ ΠΏΠ΅ΡΠΈΠΎΠ΄Π΅ ΠΈΡΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈΠ½ΡΡΠ»ΡΡΠ°. ΠΠ°ΡΠ΅ΡΠΈΠ°Π» ΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ. ΠΠ·ΠΌΠ΅ΡΠ΅Π½Ρ ΠΏΠΎΠΊΠ°Π·Π°ΡΠ΅Π»ΠΈ ΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠΈ 10 Π·ΠΎΠ½ Π±Π΅Π»ΠΎΠ³ΠΎ ΠΈ ΡΠ΅ΡΠΎΠ³ΠΎ Π²Π΅ΡΠ΅ΡΡΠ²Π° Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π° Ρ 30 ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² Π² ΠΎΡΡΡΠΎΠΌ ΠΏΠ΅ΡΠΈΠΎΠ΄Π΅ ΠΈΡΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈΠ½ΡΡΠ»ΡΡΠ° ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π΄ΠΈΡΡΡΠ·ΠΈΠΎΠ½Π½ΠΎ-ΡΠ΅Π½Π·ΠΎΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΡ. ΠΡΠ΅Π½Π΅Π½Ρ ΠΏΠΎΠΊΠ°Π·Π°ΡΠ΅Π»ΠΈ Π½Π΅Π²ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ (NIHSS), ΠΊΠΎΠ³Π½ΠΈΡΠΈΠ²Π½ΠΎΠ³ΠΎ (MMSE), ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΡΠ°ΡΡΡΠΎΠ² (ΠΈΠ½Π΄Π΅ΠΊΡ ΠΌΠΎΠ±ΠΈΠ»ΡΠ½ΠΎΡΡΠΈ Π ΠΈΠ²Π΅ΡΠΌΠΈΠ΄ ΠΈ ΠΌΠΎΠ΄ΠΈΡΠΈΡΠΈΡΠΎΠ²Π°Π½Π½Π°Ρ ΡΠΊΠ°Π»Π° Π Π΅Π½ΠΊΠΈΠ½Π°), Π° ΡΠ°ΠΊΠΆΠ΅ Π»Π°Π±ΠΎΡΠ°ΡΠΎΡΠ½ΠΎ-ΠΈΠ½ΡΡΡΡΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. ΠΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ ΡΠ°Π·Π»ΠΈΡΠΈΡ ΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠΈ Π½Π° ΡΡΠΎΡΠΎΠ½Π΅ ΠΎΡΠ°Π³Π° ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΡ ΠΈ ΡΠΈΠΌΠΌΠ΅ΡΡΠΈΡΠ½ΡΡ
ΡΡΠ°ΡΡΠΊΠ°Ρ
Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π°. ΠΡΡΠ²Π»Π΅Π½ΠΎ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΠ΅ ΠΏΠΎΠΊΠ°Π·Π°ΡΠ΅Π»Ρ Π² Π·ΠΎΠ½Π΅ Π·Π°Π΄Π½Π΅ΠΉ Π½ΠΎΠΆΠΊΠΈ Π²Π½ΡΡΡΠ΅Π½Π½Π΅ΠΉ ΠΊΠ°ΠΏΡΡΠ»Ρ Π½Π° ΡΡΠΎΡΠΎΠ½Π΅ ΠΎΡΠ°Π³Π° ΠΏΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ Ρ ΡΠΈΠΌΠΌΠ΅ΡΡΠΈΡΠ½ΡΠΌΠΈ Π·ΠΎΠ½Π°ΠΌΠΈ ΠΈΠ½ΡΠ°ΠΊΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»ΡΡΠ°ΡΠΈΡ Π²Π½Π΅ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΎΡ ΡΠ°ΡΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΡ Π·ΠΎΠ½Ρ ΠΈΠ½ΡΠ°ΡΠΊΡΠ°. ΠΡΠΎΠ΄Π΅ΠΌΠΎΠ½ΡΡΡΠΈΡΠΎΠ²Π°Π½Π° Π²Π·Π°ΠΈΠΌΠΎΡΠ²ΡΠ·Ρ ΠΌΠ΅ΠΆΠ΄Ρ Π·Π½Π°ΡΠ΅Π½ΠΈΡΠΌΠΈ ΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠΈ Π² ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π½ΡΡ
Π·ΠΎΠ½Π°Ρ
ΡΠΎ ΡΡΠ΅ΠΏΠ΅Π½ΡΡ Π½Π΅Π²ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π΄Π΅ΡΠΈΡΠΈΡΠ° ΠΈ ΠΊΠΎΠ³Π½ΠΈΡΠΈΠ²Π½ΡΠΌ ΡΡΠ°ΡΡΡΠΎΠΌ ΠΏΡΠΈ Π²ΡΠΏΠΈΡΠΊΠ΅, Π° ΡΠ°ΠΊΠΆΠ΅ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡΡ Π»Π΅ΡΠ΅Π½ΠΈΡ. ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. ΠΡΠΎΠ²Π΅Π΄Π΅Π½Π½ΠΎΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΌΠΎΠΆΠ΅Ρ ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΠΎΠ²Π°ΡΡ ΠΎ ΡΠΎΠΌ, ΡΡΠΎ ΡΠΆΠ΅ Π² ΠΎΡΡΡΠΎΠΌ ΠΏΠ΅ΡΠΈΠΎΠ΄Π΅ ΠΈΡΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈΠ½ΡΡΠ»ΡΡΠ° ΠΏΠ°ΡΠ°Π»Π»Π΅Π»ΡΠ½ΠΎ ΠΈΠ½ΠΈΡΠΈΠΈΡΡΡΡΡΡ ΠΏΡΠΎΡΠ΅ΡΡΡ Π½Π΅ΠΉΡΠΎΠ΄Π΅Π³Π΅Π½Π΅ΡΠ°ΡΠΈΠΈ ΠΈ Π½Π΅ΠΉΡΠΎΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠΈ, ΠΏΡΠΎΡΠ²Π»ΡΡΡΠΈΠ΅ΡΡ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ΠΌ ΠΈΠ½ΡΠ΅Π³ΡΠ°Π»ΡΠ½ΠΎΡΡΠΈ Π±Π΅Π»ΠΎΠ³ΠΎ ΠΈ ΡΠ΅ΡΠΎΠ³ΠΎ Π²Π΅ΡΠ΅ΡΡΠ²Π° Π³ΠΎΠ»ΠΎΠ²Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ·Π³Π°. Π ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π΅Π½ΠΈΠ΅ ΠΊΠΎΠ½ΡΠ΅ΠΏΡΠΈΠΈ βΡΠ΅ΡΠ΄ΡΠ΅-ΡΠΎΡΡΠ΄Ρ-ΠΌΠΎΠ·Π³β ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ Π΄Π°Π½Π½ΡΠ΅ ΠΎ Π·Π½Π°ΡΠΈΠΌΠΎΡΡΠΈ ΡΠΎΡΡΠ΄ΠΈΡΡΡΡ
ΡΠ°ΠΊΡΠΎΡΠΎΠ² ΡΠΈΡΠΊΠ°, ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»ΠΈΠ²Π°ΡΡΠΈΡ
Π³ΠΈΠΏΠΎΠΏΠ΅ΡΡΡΠ·ΠΈΡ ΠΈ Π³ΠΈΠΏΠΎΠΊΡΠΈΡ, Π² ΡΠ°Π·Π²ΠΈΡΠΈΠΈ ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΠ½ΡΡ
ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΉ ΠΈΠ·ΡΡΠ΅Π½Π½ΡΡ
Π·ΠΎΠ½ ΠΌΠΎΠ·Π³Π°. Π ΡΠ΄ ΠΏΠΎΠΊΠ°Π·Π°ΡΠ΅Π»Π΅ΠΉ ΡΡΠ°ΠΊΡΠΈΠΎΠ½Π½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠΈ, ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½Π½ΡΡ
Π² ΡΠ°Π±ΠΎΡΠ΅, ΠΌΠΎΠ³ΡΡ ΡΠ»ΡΠΆΠΈΡΡ ΠΏΡΠ΅Π΄ΠΈΠΊΡΠΎΡΠ°ΠΌΠΈ Π½Π΅Π²ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΈΡΡ
ΠΎΠ΄Π° ΠΏΡΠΈ Π²ΡΠΏΠΈΡΠΊΠ΅ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² ΠΈΠ· ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ°
Limit Distributions for the Estimates of the Digamma Distribution Parameters Constructed from a Random Size Sample
In this paper, we study a new type of distribution that generalizes distributions from the gamma and beta classes that are widely used in applications. The estimators for the parameters of the digamma distribution obtained by the method of logarithmic cumulants are considered. Based on the previously proved asymptotic normality of the estimators for the characteristic index and the shape and scale parameters of the digamma distribution constructed from a fixed-size sample, we obtain a statement about the convergence of these estimators to the scale mixtures of the normal law in the case of a random sample size. Using this result, asymptotic confidence intervals for the estimated parameters are constructed. A number of examples of the limit laws for sample sizes with special forms of negative binomial distributions are given. The results of this paper can be widely used in the study of probabilistic models based on continuous distributions with an unbounded non-negative support
Asymptotically Normal Estimators for the Parameters of the Gamma-Exponential Distribution
Currently, much research attention has focused on generalizations of known mathematical objects in order to obtain adequate models describing real phenomena. An important role in the applied theory of probability and mathematical statistics is the gamma class of distributions, which has proven to be a convenient and effective tool for modeling many real processes. The gamma class is quite wide and includes distributions that have useful properties such as, for example, infinite divisibility and stability, which makes it possible to use distributions from this class as asymptotic approximations in various limit theorems. One of the most important tasks of applied statistics is to obtain estimates of the parameters of the model distribution from the available real data. In this paper, we consider the gamma-exponential distribution, which is a generalization of the distributions from the gamma class. Estimators for some parameters of this distribution are given, and the asymptotic normality of these estimators is proven. When obtaining the estimates, a modified method of moments was used, based on logarithmic moments calculated on the basis of the Mellin transform for the generalized gamma distribution. On the basis of the results obtained, asymptotic confidence intervals for the estimated parameters are constructed. The results of this work can be used in the study of probabilistic models based on continuous distributions with an unbounded non-negative support
The Estimators of the Bent, Shape and Scale Parameters of the Gamma-Exponential Distribution and Their Asymptotic Normality
When modeling real phenomena, special cases of the generalized gamma distribution and the generalized beta distribution of the second kind play an important role. The paper discusses the gamma-exponential distribution, which is closely related to the listed ones. The asymptotic normality of the previously obtained strongly consistent estimators for the bent, shape, and scale parameters of the gamma-exponential distribution at fixed concentration parameters is proved. Based on these results, asymptotic confidence intervals for the estimated parameters are constructed. The statements are based on the method of logarithmic cumulants obtained using the Mellin transform of the considered distribution. An algorithm for filtering out unnecessary solutions of the system of equations for logarithmic cumulants and a number of examples illustrating the results obtained using simulated samples are presented. The difficulties arising from the theoretical study of the estimates of concentration parameters associated with the inversion of polygamma functions are also discussed. The results of the paper can be used in the study of probabilistic models based on continuous distributions with unbounded non-negative support
Post-operative insulin resistance
Post-operative insulin resistance (IR) is a recognised marker of surgical stress. However, the reasons underlying post-operative IR and its clinical value are still unclear. IR has been described as a pathological condition, in which organs and tissues fail to respond to the hormone insulin, resulting in acute hyperglycaemia. Post-operative IR in patients without type 2 diabetes has been identified as an independent, negative predictor of post-operative outcome. Studies have shown a direct relationship between post-operative morbidity (including complications from infection) and total mortality in patients with acute hyperglycaemia compared with diabetic patients. IR and stress-induced hyperglycaemia in the early post-operative period may be corrected by insulin infusion; however, this has often been associated with hypoglycaemia. Detection and modification of risk factors in the pre- and intra-operative periods may decrease the frequency of IR and hyperglycaemia and eliminate the use of insulin. In this literature review, the mechanisms underlying the development and prevention of post-operative IR, and its clinical value are discussed. This study demonstrates the relationship between IR and post-operative morbidity, highlighting the benefits of a complex approach to prevent the adverse events of post-operative IR and stress-induced hyperglycaemia
Formation of solitons in a waveguide at second harmonic generation
Second harmonic generation in a quadratic nonlinear waveguide is analyzed analytically and numerically. Formation of spatio-temporal solitons is demonstrated. They can form both positive and negative coefficients of group velocity dispersion due to the waveguide geometry. Analytical results are confirmed by computer simulations
Formation of solitons in a waveguide at second harmonic generation
Second harmonic generation in a quadratic nonlinear waveguide is analyzed analytically and numerically. Formation of spatio-temporal solitons is demonstrated. They can form both positive and negative coefficients of group velocity dispersion due to the waveguide geometry. Analytical results are confirmed by computer simulations