V hybridisa?nim pokuse bylo studováno dědi?ně zalo?eni mutaci vzniklě větevnatě formy ?ita, vyzna?ujici se zmno?eným po?tem kvltk? v kláscich a květnich ?ásti ve kvitcich. Zjistilo se, ?e dědi?né zalo?eni těto formy bylo monomerně recesivni v??i odr?dě ?ita Dob?enickě trsnatě, s normálnim utvá?enim klasu. Ukázalo se takě, ?e ani zvlá?? dobré, ani zvlá?? ?patné p?dni podminky neovlivnily ?těpný poměr 3 : 1 v F2 generaci. Studovaná muta?ni forma byla stabilni v dosti ?irokém intervalu p?dnich a klimatických podminek. Jde zde patrně o stabilni poruchu v morfogenetickém procesu, vedoucim k utvá?eni klasu. 相似文献
A methylene group in the fluorinated carbon backbone of 1H,1H,2H,2H,8H,8H–perfluorododecanol (degradable telomer fluoroalcohol, DTFA) renders the molecule cleavable by microbial degradation into two fluorinated carboxylic acids. Several biodegradation products of DTFA are known, but their rates of conversion and fates in the environment have not been determined. We used liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) to quantitatively investigate DTFA biodegradation by the microbial community in activated sludge in polyethylene terephthalate (PET) flasks, which we also determined here showed least adsorption of DTFA. A reduction in DTFA concentration in the medium was accompanied by rapid increases in the concentrations of 2H,2H,8H,8H–perfluorododecanoic acid (2H,2H,8H,8H–PFDoA), 2H,8H,8H-2-perfluorododecenoic acid (2H,8H,8H-2-PFUDoA), and 2H,2H,8H-7-perfluorododecenoic acid and 2H,2H,8H-8-perfluorododecenoic acid (2H,2H,8H-7-PFUDoA/2H,2H,8H-8-PFUDoA), which were in turn followed by an increase in 6H,6H–perfluorodecanoic acid (6H,6H–PFDeA) concentration, and decreases in 2H,2H,8H,8H–PFDoA, 2H,8H,8H-2-PFUDoA, and 2H,2H,8H-7-PFUDoA/2H,2H,8H-8-PFUDoA concentrations. Accumulation of perfluorobutanoic acid (PFBA), a presumed end product of DTFA degradation, was also detected. Our quantitative and time-course study of the concentrations of these compounds reveals main routes of DTFA biodegradation, and the presence of new biodegradation pathways.
We investigated the evolutionary history of the divergent vertebrate linker histones H10, H5, and HIM. We observed that the sequence of the central conserved domain of these vertebrate proteins shares characteristic features with histone H1 proteins of plants and invertebrate animals which otherwise never appear in any vertebrate histone H1 protein. A quantitative analysis of 58 linker histone sequences also reveals that these proteins are more similar to invertebrate and plant histone H1 than to histone H1 of vertebrates. A phylogenetic tree deduced from an alignment of the central domain of all known linker histones places H10, H5, and HIM in close vicinity to invertebrate sperm histone H1 proteins and to invertebrate histone H1 proteins encoded by polyadenylated mRNAs. We therefore conclude that the ancestors of the vertebrate linker histones H10, H5, and HIM diverged from the main group of histone H1 proteins before the vertebrate type of histone H1 was established in evolution. We discuss this observation in the general context of linker histone evolution.
Correspondence to: B. and E. Schulze 相似文献
Les maladies auto-immunes du foie, en particulier la cirrhose biliaire primitive (CBP) et les hépatites auto-immunes (HAI)
sont des maladies spécifiques d’organes dont la définition est à la fois clinique, histologique et biologique. La recherche
des autoanticorps sériques est une étape essentielle à leur diagnostic (1). 相似文献
Summary A sensitive method to assign H protons stereospecifically as well as to determine rotamer populations about 1, in two 3D experiments is presented. The SOFT-HCCH-COSY experiment allowed us to measure the3J(H,C) couplings, using constant time evolution of C in t2 and Caliphatic-selective decoupling during t3. The SOFT-HCCH-E.COSY experiment allowed us to measure the3J(H,H) couplings, using constant time evolution of C in t2, a small flip angle1H excitation pulse in the second mixing time, and double-band-selective decoupling (aliphatic and carbonyl carbons) during t3. The method was applied to ribonuclease T1. 相似文献
We present a theoretical study on the detailed mechanism and kinetics of the H+HCN →H+HNC process. The potential energy surface was calculated at the complete basis set quantum chemical method, CBS-QB3. The vibrational frequencies and geometries for four isomers (H2CN, cis-HCNH, trans-HCNH, CNH2), and seven saddle points (TSn where n = 1 ? 7) are very important and must be considered during the process of formation of the HNC in the reaction were calculated at the B3LYP/6-311G(2d,d,p) level, within CBS-QB3 method. Three different pathways (PW1, PW2, and PW3) were analyzed and the results from the potential energy surface calculations were used to solve the master equation. The results were employed to calculate the thermal rate constant and pathways branching ratio of the title reaction over the temperature range of 300 up to 3000 K. The rate constants for reaction H + HCN → H + HNC were fitted by the modified Arrhenius expressions. Our calculations indicate that the formation of the HNC preferentially occurs via formation of cis–HCNH, the fitted expression is kPW2(T) = 9.98 × 10?22T2.41 exp(?7.62 kcal.mol?1/RT) while the predicted overall rate constant kOverall(T) = 9.45 × 10?21T2.15 exp(?8.56 kcal.mol?1/RT) in cm3 molecule?1s?1.
Calculations performed at the ab initio level using the recently reported planar concentric π-aromatic B18H62+(1) [Chen Q et al. (2011) Phys Chem Chem Phys 13:20620] as a building block suggest the possible existence of a new class of B3nHm polycyclic aromatic hydroboron (PAHB) clusters—B30H8(2), B39H92?(3), B42H10(4/5), B48H10(6), and B72H12(7)—which appear to be the inorganic analogs of the corresponding CnHm polycyclic aromatic hydrocarbon (PAHC) molecules naphthalene C10H8, phenalenyl anion C13H9?, phenanthrene/anthracene C14H10, pyrene C16H10, and coronene C24H12, respectively, in a universal atomic ratio of B:C?=?3:1. Detailed canonical molecular orbital (CMO), adaptive natural density partitioning (AdNDP), and electron localization function (ELF) analyses indicate that, as they are hydrogenated fragments of a boron snub sheet [Zope RR, Baruah T (2010) Chem Phys Lett 501:193], these PAHB clusters are aromatic in nature, and exhibit the formation of islands of both σ- and π-aromaticity. The predicted ionization potentials of PAHB neutrals and electron detachment energies of small PAHB monoanions should permit them to be characterized experimentally in the future. The results obtained in this work expand the domain of planar boron-based clusters to a region well beyond B20, and experimental syntheses of these snub B3nHm clusters through partial hydrogenation of the corresponding bare B3n may open up a new area of boron chemistry parallel to that of PAHCs in carbon chemistry.
Figure
Ab initio calculations predict the existence of polycyclic aromatic hydroboron clusters as fragments of a boron snub sheet; these clusters are analogs of polycyclic aromatic hydrocarbons 相似文献