Late Carboniferous intra-arc sediments in the north Chilean Andes: Stratigraphy,paleogeography and paleoclimate

Summary Thick terrestrial Late Carboniferous to Triassic volcanosedimentary successions, a prominent feature of the Chilean and Argentinian High Andes, were formed on the active continental margin of Gondwanaland. Their stratigraphic position and the paleogeographic and paleoclimatic relations to neighbouring successions are poorly defined. A more precise age has been obtained for alluviolimnic intra-arc sediments (Miembro Medio), which are intercalated in the Late Carboniferous-Triassic volcano-sedimentary successions in the Salar de Atacama area of northern Chile. The ostracodesCarbonita cf.pungens andParaparchites sp., which occur in the lower part of the Miembro Medio, are of Late Carboniferous, probably Westphalian age. The diverse taphoflora, which occurs in a higher stratigraphic level than the ostracodes, includes sphenophytes, ferns, gymnosperms and pteridophylls, for which we assume a late Westphalian-Early Permian age. Considering radiometric data of under-and overlying volcanic rocks, a Westphalian-Stephanian (to? Early Permian) age is inferred for the Miembro Medio. Fauna and flora indicate that warm-humid and seasonal climatic conditions existed during the deposition of the lower fossiliferous part of the Miembro Medio. This coincides with the sedimentary paleoclimatic indicators of the Miembro Medio and the climate which was assumed to have predominated in wide parts of the Central and Southern Andes during the Latest Carboniferous.     

月腺大戟根中有效成分乙素和丙素的结构研究

本文主要报道从月腺大戟(Euphorbia ebracteolata Hayata)根中分离出的对结核菌有抑制作用的晶Ⅵ(乙素)和晶Ⅶ(丙素)的化学结构。经化学反应及光谱鉴定,确定晶Ⅵ为2,4-二羟基-6-甲氧基-3-甲基-苯乙酮,晶Ⅶ为2-羟基-6-甲氧基-3-甲基-1-苯乙酮-4-6-葡萄糖甙。乙素为首次分离的天然产物,丙素为新的化合物。该植物提取物对结核病有明显疗效。     

Actin aggregation and embryonic epidermal wound healing

Recent experiments on the response of embryonic epidermis to wounding have revealed a cable of filamentous actin at the wound edge, which may be responsible for healing (Martin and Lewis 1991, 1992). We investigate the important question of how the cable forms as a response to wounding. We modify the mechanical model of Murray and Oster (1984) to investigate the post-wounding equilibrium in the epidermal sheet. We analyse the model in both one-dimensional and radially symmetric two-dimensional geometries, to determine the parameter domain in which a solution exists. We show that in both geometries the model solutions reflect the phenomenon of the actin cable for parameter values close to one edge of this domain. We interpret these results in terms of the relative rates of intracellular reorganization of actin and myosin, and thus suggest a possible mechanism for the formation of the actin cable.     

~（14）C－涕灭威在旱田土壤中的降解

研究了１４Ｃ－涕灭威在５种土壤中（４ｐｐｍ,互．２２μＣｉ·５０ｇ－１土壤干重）的生物降解．模拟试验为密闭系统,土壤中水分含量为２２％,气温２０—３０Ｃ℃在供试的５种土壤中,北京肖家河的土壤降解最快,为施人放射剂量的５１．３％,以“ＣＯ：形式从土壤进出;２６．０％与土壤结合,只有２１．６％可以被抽出．取自浙江义乌的土壤降解较慢,收集到的１４ＣＯ２为施入量的２３．３％．土壤中加入杀菌剂红霉素或敌茵丹降解作用明显减慢．土壤提取物中涕灭威亚砜、涕灭威亚砜肟被确认是主要的代谢产物,还发现了少量的涕灭威砜,涕灭威亚砜腈涕灭威砜腈和涕灭威砜肟等降解物．     

用诺卡氏菌酶法转化顺式环氧琥珀酸生产L（＋）—酒石酸的研究

L(+)酒石酸(又称d-酒石酸),是一种重要的食品添加剂和医药拆分剂,在食品工业、医药工业和化学工业中有广泛用途。传统的L(+)酒石酸是从葡萄酒副产物酒石中提取的。世界主要厂商在西欧。随着世界经济发展,对酒石酸的需求量越来越大,由于酒石供应量有限,酒石酸因此不能满足供应。而且常常受气候、葡萄种植业、葡萄酒酿造业的影响,导致较大的价格波动。因此开发新的酒石酸生产方法就必然引起人们重视。 早年(1929年)就有发酵法直接从葡萄     

Selenium and Behçet's disease

Behçet's disease is an inflammatory disorder of unknown etiology, characterized by recurrent oral and genital aphthous ulcers, ocular inflammation, and skin lesions of erythema nodusum and acneiformeruptions. Selenium (Se) affects all components of the immune system, i.e., the development and expression of nonspecific, humoral, and cell-mediated responses. In general, a deficiency in Se appears to result in immunosuppression, whereas supplementation with low doses of Se appears to result in augmentation and/or restoration of immunoglogic functions. In this study, the distribution of Se and IgG, IgM in serum were compared in samples from healthy adult control and Behçet's disease patients. The serum Se levels were measured by AA-30-40 Varian Spectra, and immunoglobulins were measured by immunodiffusion technique. The mean (SD) serum Se level of 54.24 ± 8.06 ng/mL among Behçet's disease subjects was significantly different (P<0.01) from that in the control subjects (90.01 ± 9.94 ng/mL). We also measured IgG and IgM as 10.01 ± 2.74 mg/mL and 1.26 ± 0.29 mg/mL, respectively for patients, and 15.08 ± 4.73 mg/mL and 1.58 ± 0.43 mg/mL for controls. The mean values of IgG and IgM for patients were significantly (P<0.05) different from the values of controls. It seems, therefore, that a deficiency in selenium impedes the humoral immune response.     

Iron coordination geometry in full-length, truncated, and dehydrated forms of human tyrosine hydroxylase studied by Mössbauer and X-ray absorption spectroscopy

Full-length human tyrosine hydroxylase 1 (hTH1) and a truncated enzyme lacking the 150 N-terminal amino acids were expressed in Escherichia coli and purified either with or without (6×histidine) N-terminal tags. After reconstitution with ⁵⁷Fe(II), the Mössbauer and X-ray absorption spectra of the enzymes were compared before and after dehydration by lyophilization. Before dehydration, >90% of the iron in hTH1 had Mössbauer parameters typical for high-spin Fe(II) in a six-coordinate environment [isomer shift δ(1.8–77?K)=1.26–1.24?mm s^–1 and quadrupole splitting ΔE _Q=2.68?mm s^–1]. After dehydration, the Mössbauer spectrum changed and 63% of the area could be attributed to five-coordinate high-spin Fe(II) (δ=1.07?mm s^–1 and ΔE _Q=2.89?mm s^–1 at 77?K), whereas 28% of the iron remained as six-coordinate high-spin Fe(II) (δ=1.24?mm s^–1 and ΔE _Q=2.87?mm s^–1 at 77?K). Similar changes upon dehydration were observed for truncated TH either with or without the histidine tag. After rehydration of hTH1 the spectroscopic changes were completely reversed. The X-ray absorption spectra of hTH1 in solution and in lyophilized form, and for the truncated protein in solution, corroborate the findings derived from the Mössbauer spectra. The pre-edge peak intensity of the protein in solution indicates six-coordination of the iron, while that of the dehydrated protein is typical for a five-coordinate iron center. Thus, the active-site iron can exist in different coordination states, which can be interconverted depending on the hydration state of the protein, indicating the presence or absence of a water molecule as a coordinating ligand to the iron. The present study explains the difference in iron coordination determined by X-ray crystallography, which has shown a five-coordinate iron center in rat TH, and by our recent spectroscopic study of human TH in solution, which showed a six-coordinated iron center.     

Simultaneous interpretation of Mössbauer, EPR and 57Fe ENDOR spectra of the [Fe4S4] cluster in the high-potential iron protein I Ectothiorhodospira halophila

4 S₄]^3 + and the reduced [Fe₄S₄]^2 + clusters in the high-potential iron protein I from Ectothiorhodospira halophila were measured in a temperature range from 5 K to 240 K. EPR measurements and ⁵⁷Fe electron-nuclear double resonance (ENDOR) experiments were carried out with the oxidized protein. In the oxidized state the cluster has a net spin S = 1/2 and is paramagnetic. As common in [Fe₄S₄]^3 + clusters, the M?ssbauer spectrum was simulated with two species contributing equally to the absorption area: two Fe^3 + atoms couple to the “ferric-ferric” pair, and one Fe^2 + and one Fe^3 + atom give the “ferric-ferrous pair”. For the simulation of the M?ssbauer spectrum, g-values were taken from EPR measurements. A-tensor components were determined by ⁵⁷Fe ENDOR experiments that turned out to be a necessary source of estimating parameters independently. In order to obtain a detailed agreement of M?ssbauer and ENDOR data, electronic relaxation has to be taken into account. Relaxing the symmetry condition in a way that the electric field gradient tensor does not coincide with g- and A-tensors yielded an even better agreement of experimental and theoretical M?ssbauer spectra. Spin-spin and spin-lattice relaxation times were estimated by pulsed EPR; the former turned out to be the dominating mechanism at T = 5 K. Relaxation times measured by pulsed EPR and obtained from the M?ssbauer fit were compared and yield nearly identical values. The reduced cluster has one additional electron and has a diamagnetic (S = 0) ground state. All the four irons are indistinguishable in the M?ssbauer spectrum, indicating a mixed-valence state of Fe^2.5 + for each. Received: 15 February 1999 / Accepted: 31 August 1999     

Investigation of structure and antigenic capacities of Thermococcales cell envelopes and reclassification of "Caldococcus litoralis" Z-1301 as Thermococcus litoralis Z-1301

Fourteen strains of hyperthermophilic organotrophic anaerobic marine Archaea were isolated from shallow water and deep-sea hot vents, and four of them were characterized. These isolates, eight previously published strains, and six type strains of species of the order Thermococcales were selected for the study of cell wall components by means of thin sectioning or freeze-etching electron microscopy. The cell envelopes of most isolates were shown to consist of regularly arrayed surface protein layers, either single or double, with hexagonal lattice (p6) symmetry, as the exclusive constituents outside the cytoplasmic membrane. The S-layers studied differed in center-to-center spacing and molecular mass of the constituent protein subunits. Polyclonal antisera raised against the cells of 10 species were found to be species-specific and allowed 12 new isolates from shallow water hot vents to be identified as representatives of the species Thermococcus litoralis, Thermococcus stetteri, Thermococcus chitonophagus, and Thermococcus pacificus. Of the 7 deep-sea isolates, only 1 was identified as a T. litoralis strain. Thus, hyperthermophilic marine organotrophic isolates obtained from deep-sea hot vents showed greater diversity with regard to their S-layer proteins than shallow water isolates. Received: February 5, 1999 / Accepted: May 11, 1999     

Process monitoring of an industrial fed-batch fermentation

Market demand places great emphasis in industry on product quality. Consequently, process monitoring and control have become important aspects of systems engineering. In this article we detail the results of a 2-year study focusing on the development of a condition monitoring system for a fed-batch fermentation system operated by Biochemie Gmbh in Austria. We also demonstrate the suitability and limitations of current state of the art technologies in this field and suggest novel modifications and configurations to improve their suitability for application to a fed-batch fermentation system.