Field experiments were conducted in Sicily (south Italy) during two seasons to characterize by chlorophyll (Chl) fluorescence four genotypes (Spunta, Sieglinde, Daytona, and Ninfa) of potato (Solanum tuberosum L.) for off-season production during plant aging and to analyse the possible relation between Chl parameters and tuber yield. Chl fluorescence parameters [initial fluorescence (F0), maximum fluorescence (Fm), Fv/Fm, time in which maximal fluorescence occurs (Tmax)] gained from Kautsky kinetics and Chl content were measured weekly, from 5th to 6th leaf appearance to beginning of plant senescence in the first season and to full plant senescence in the second season. F0 and Fv/Fm were the most reliable Chl fluorescence parameters for the definition of genotypic differences while Chl content and Tmax were the most reliable Chl parameters to predict plant aging. Tuber yield was highly correlated with Chl content, Tmax, F0, and Fm.
The rod-like structures containing ribosome particles isolated from cell membranes of the cyanobacterium Phormidium laminosum were sensitive to RNAase and capable to incoiporate in viíro ■'♦C-amino acids into polypeptides. These facts can be considered as an evidence for the presence of protein-synthesizing apparatus in the rod-like structures of cyanobacterial membranes.
The photosynthetic election transport activities in beet spinách thylakoids were studied using ruthenium chloride as an electron acceptor, Like potassium ferricyanide, RUCI3 supported the non-cyclic electron flow with net evolution of oxygen. The rate of oxygen evolution was at its maximum with 0.5 mM RUCI3 at pH of 8.0 and the election flow coupled to translocation of protons into the thylakoid vesicles. Ruthenium chloride-supported oxygen evolution was inhibited by specific photosynthetic electron tiansport inhibitors like diuron, dibromothymoquinone, potassium cyanide, and mercuric chloride Unlike ferricyanide, the RuCl3-supported oxygen evolution was totally inliibited by potassium cyanide and mercuric chloride at both pH 8.0 and 6.5. Since potassium cyanide and mercuric chloride mostly interrupt the electron flow at plastocyanin level, RUCI3 probably accepts electrons mostly from photosystem 1 or its near vicinity. Besides electron acceptance, RUCI3 suppresses the photophosphoiylation activity in a manner similar to energy transfer inhibitors.
Catalytic test reaction of methylbutynol (MBOH) conversion was applied to investigation of natural clays and non-clay minerals from Jordanian (bentonite, kaolinite, diatomite, zeolit e) and Russian (palygorskite, kaolinite, hydromica) deposits as well as H-ZSM-5. Palygorskite and kaolinite containing samples have shown the highest catalytic activity. Conversionove r Jordanian clay minerals decreased in the order: zeolite > bentonite > red kaolinite > white kaolinite > diatomite that agreed to change of acidity, surface area of samples. Sufficient deactivation was observed for H-ZSM-5, kaolinite and hydromica due to adsorption of secondary product in micropores of raw minerals. Products of both acidic and basic pathways of test reaction were formed indicating the presence of acid and basic sites on clays surface, apart from acidic catalyst H-ZSM-5. Theyield ratio of acidic to basic products was above the unity for zeolite, bentonite, red kaolinite, and palygorskite; equal to unity for diatomite and hydromica, and less then unity for white kaolinite. It was observed for kaolinite containing sample that high activation temperature increased conversion of MBOH owing to fo rmation of additional basic sites as a result of mineral dehydroxylation. Rise of montmorillonite content from 30 to 80 % provided 91-97 % of MBOH conversion., Lyudmila Novikova, Larisa Belchinskaya, Frank Roessner and Murad Alsawalha., and Obsahuje bibliografické odkazy
In this review we present immunohistochemical methods for visualization of capillaries and muscle fibres in thick muscle sections. Special attention is paid to the procedures that preserve good morphology. Applying confocal microscopy and virtual 3D stereological grids, or tracing of capillaries in virtual reality, length of capillaries within a muscle volume or length of capillaries adjacent to a muscle fibre per fibre length, fibre surface area or fibre volume can be evaluated by an unbiased approach. Moreover, 3D models of capillaries and muscle fibres can be produced. Comparison of the developed methods with counting capillary profiles from 2D sections is discussed and the reader is warned that counting capillary profiles from 2D sections can underestimate the capillary length by as much as 75 percent. Application of the described 3D methodology is illustrated by the anatomical remodelling of capillarity during acute denervation and early reinnervation in the ra t soleus and extensor digitorum longus muscles., I. Eržen, J. Janáček, L. Kubínová., and Obsahuje bibliografii a bibliografické odkazy
The complete mitochondrial genome (mitogenome) of Spilarctia robusta (Lepidoptera: Noctuoidea: Erebidae) was sequenced and analyzed. The circular mitogenome is made up of 15,447 base pairs (bp). It contains a set of 37 genes, with the gene complement and order similar to that of other lepidopterans. The 12 protein coding genes (PCGs) have a typical mitochondrial start codon (ATN codons), whereas cytochrome c oxidase subunit 1 (cox1) gene utilizes unusually the CAG codon as documented for other lepidopteran mitogenomes. Four of the 13 PCGs have incomplete termination codons, the cox1, nad4 and nad6 with a single T, but cox2 has TA. It comprises six major intergenic spacers, with the exception of the A+T-rich region, spanning at least 10 bp in the mitogenome. The nucleotide composition of the genome is greatly A+T biased (81.09%), with a negative AT skewness (-0.007), indicating the presence of fewer As than Ts, similar to other Noctuoidea. The A+T-rich region is 343 bp long, and contains some conserved regions, including an "ATAGA" motif followed by a 19 bp poly-T stretch, a microsatellite-like (AT)9 and a poly-A element, a characteristic shared with other lepidopteran mitogenomes. Phylogenetic analysis, based on 13 PCGs using Maximum likelihood methods revealed that S. robusta belongs to the superfamily Noctuoidea., Yu Sun, Sen Tian, Cen Qian, Yu-Xuan Sun, Muhammad N. Abbas, Saima Kausar, Lei Wang, Guoqing Wei, Bao-Jian Zhu, Chao-Liang Liu., and Obsahuje bibliografii
A total of 23 genotypes belonging to seven tropical food yams and two wild relative species of different origin and coming from two sampling ecological zones (the Republic of Benin in Africa and Guadeloupe in the Caribbean) was analysed for their 13C content. The δ13C values for all yam samples (from -25.39 and -30.07 ‰) indicated that all species had a C3 photosynthetic type. and D. Cornet, J. Sierra, R. Bonhomme.
Carotenoids (Car) regulate energy flow in photosynthesis by a specific Car-chlorophyll (Chl) interaction in the singlet-excited states, leading to a reduction in Chl fluorescence. We studied quenching of Chl a-fluorescence in benzene by trans-β-carotene. Non-linear analysis of the quenching process enables to explain the possible molecular mechanism leading to the de-excitation of Chl a. The fluorescence intensity was measured at 670 nm for excitation wavelengths of 380, 430, 640, and 650 nm. The β -carotene concentrations ranged from 4×10-5 M to 5×10-3 M. When the samples were excited at 640 and 650 nm, the Stern-Volmer plots showed that the quenching process has high rate constants, hence β-carotene is a very efficient quencher. Two different types of quenching process could take place. and D. M. Gazdaru, B. Iorga.
Morphological characteristics of ripples are analyzed considering bed surfaces as two dimensional random fields of bed elevations. Two equilibrium phases are analyzed with respect to successive development of ripples based on digital elevation models. The key findings relate to the shape of the two dimensional second-order structure functions and multiscaling behavior revealed by higher-order structure functions. Our results suggest that (1) the two dimensional second-order structure functions can be used to differentiate the two equilibrium phases of ripples; and (2) in contrast to the elevational time series of ripples that exhibit significant multiscaling behavior, the DEMs of ripples at both equilibrium phases do not exhibit multiscaling behavior.
The larval period in fishes has several definitions, each one deviating slightly from the other. Small discrepancies in the definitions, especially concerning the end of the larval period, can create misunderstandings when applied in practice. I examine the different definitions of a larva, the larval period, including metamorphosis, and the juvenile period. Various criteria used to identify the transition from the larval to juvenile periods are contradictory and refer mostly to the length of the larval period. Ignorance of definitions used to identify the juvenile period has caused many larvae to be regarded as juveniles. I discuss the feasibility of various definitions and the nomenclature on the basis of character evaluation. The occurrence of larval morphological characters, i.e. larval fin fold, differentiation of fins, temporary organs, absence of scale cover, non-adult like body proportions and pigmentation, is examined and some features are compared in eleven species. Irrespective of the different definitions of a larva, there are considerable differences in the schedule and duration of development in certain characters between species and, in terms of duration, also within species owing to environmental conditions. Ontogenetic processes seem to be sufficiently flexible to allow larvae to adapt to their environment, which on the other hand may also shape the phenotype. Determination of the environment in which a larva develops depends not only on the location of the spawning grounds but also on the dispersion of larvae. Dispersal strategies are examined in light of larval morphology and behaviour. After fin differentiation, the transition from larva to juvenile would seem to be best described by the dominant morphological changes in body proportions and coloration, combined with behavioural aspects and habitat changes. I suggest the differences and functional aspects of larvae be examined. The main character of larvae is that they are adapted to make use of resources not normally used by adults.