Thirty-nine isolates and additional refcrcnce strains of methanotrophic bacteria were studied with respect to mol yo G + C of their DNA and the type of intracytoplasmatic membranes. The results on the whole confirm the former classification scheme of WHITTEKBURY et-al. (1970). However, problematic groups such a s "Methylocyatis" and "41 ethylobacter" are in need of additional taxonomic studies.The present situation in nomenclature and taxonomy of methanotrophic bacteria is confused in spite of the recommendations of "Approved Lists" (SKERMANN ef nl. 1980) and the quite recently issued BERGEY 9th edit. (vol. 1). This is due partly to the lack of information and the neglect of taxonomically useful characters, and partly t o the lack of a generally accepted taxonomic guideline. However, there seems t o exist a general consensus that the scheme of WHITTENBURY et al. Type I is characterized by closely packed bundles (stacks) of membranes (flattened Type I1 is characterized by pairs of periphcrically and loosely arranged mcnihranes I n the course of ecological and taxonomic studies of obligately methanotrophic bacteria, 39 own isolates and 8 reference strains have bccri examined with reference t o their membrane type and the moly; guanine and cytosine (G T C ) of their DNA.vesicles) (Pig. 1). (Fig. 2).
Matorials and methodsThe strains studied and their sources are listed in Table 1. Intracytoplasmatic membranes were investigated by thin sectioning following the procedure of HAUBOLD (1978). The mol yo G + C of the DNA was calculated from T m values according to the method of MAEMUR and DOTY (1962) modified by HEYER and BOCKEL.Culture conditions : The methanotrophic bacteria were grown in a mineral medium (LEADBETTER and FOSTER 1958) in a 5 1 glass fermenter, which was supplied with a methane/air/CO, mixture arvested by centrifugation and conserved by freezing (-20 "C).checked microscopically.at 37 'C, followed by the addition of sodium dodecylsulfate (see under a)).
Die Spaltung von Verbindungen des Typs R2EER2 und RE′E′R (E = P, As; E′ = S, Se; R = CH3 CF3) mit den Komplexen π‐C5H5(CO)3MH (M = Cr, Mo, W) dient (a) zur Darstellung bekannter und neuer komplexsubstituierter Phosphane, Arsane, Sulfane oder Selane π‐C5H5(CO)3MER2 (I) bzw. π‐C5H5(CO)3ME′R (II), (b) zur Ermittlung der Reaktivitätsabstufung als Funktion von E, E′, R [As2(CF3)4 ≈ P2(CF3)4 > Se2Me2 ≧ S2(CF3)2 ≥ Se2(CF3)2> As2Me4 > (CF3)2AsSeMe] und M (Mo > Cr ≫ W). Die als Folgereakltion beobachtete Umwandlung der Einkernkomplexe I und II in die Zweikernverbindungen [π‐C5H5(CO)2ER2]2 bzw. [π‐C5H5(CO)2ME′R]2 zeigt in den Reihen W ≪ Mo ≪ Cr und SeCF3 < As(CF3)2 < SCF3 ≈︁ P(CF3)2 < SeMe < AsMe2 ≪ PMe2 ≈︁ SMe zunehmende Tendenz.
Abstract-We investigated exterior and interior subsamples from the Martian shergottite meteorites Allan Hills (ALH) A77005 and Roberts Massif (RBT) 04261 for secondary minerals, oxygen isotopes, Ar-Ar, and noble gas signatures. Electron microprobe investigations revealed that RBT 04261 does not contain any visible alteration even in its most exterior fractures, whereas fracture fillings in ALHA77005 penetrate into the meteorite up to 300 lm, beyond which the fractures are devoid of secondary minerals. Light noble gases seem to be almost unaffected by terrestrially induced alteration in both meteorites. Thus, a shock metamorphic overprint of 30-35 GPa can be deduced from the helium measurements in RBT 04261. Oxygen isotopes also seem unaffected by terrestrially weathering and variations can easily be reconciled with the differences in modal mineralogy of the exterior and interior subsamples. The measurements on irradiated samples (Ar-Ar) showed a clear Martian atmospheric contribution in ALHA77005, but this is less apparent in our sample of RBT 04261. Exterior and interior subsamples show slight differences in apparent ages, but the overall results are very similar between the two. In contrast, krypton and xenon are severely affected by terrestrial contamination, demonstrating the ubiquitous presence of elementally fractionated air in RBT 04261. Although seemingly contradictory, our results indicate that RBT 04261 was more affected by contamination than ALHA77005. We conclude that irrespective of on which planet the alteration occurred, exposure of Martian rocks to atmosphere (or brine) introduces noble gases with signatures elementally fractionated relative to the respective atmospheric composition into the rock, and relationships of that process with oxygen isotopes or mineralogical observations are not straightforward.
Der Einfluß der Komplexfragmente π‐C5H5(CO)3M (M Cr, Mo, W) auf die Basizität der metallierten Phosphane bzw. Arsane π‐C5H5(CO)3MER2 (E P, As; R CF3, CN) wird durch Umsetzungen mit Schwefel, Methyliodid, Fluortrichlormethan und W(CO)5THF untersucht. Die Reaktion von π‐C5H5(CO)3ME(CF3)2 (E P: 1a–c; E As: 2a–c) mit Schwefel ist nur für E P erfolgreich und liefert die Komplexe π‐C5H5(CO)3P(S)(CF3)2 (5a–c) in guten Ausbeuten. Die thermische Umwandlung der Phosphansulfide in Verbindungen mit η2‐gebundenem (CF3)2PS‐Liganden gelingt nicht. Die Umsetzungen von 1a–c, 2a–c und π‐C5H5(CO)3MP(CN)2 (3a–c) mit CH3I oder CCl3F führen nicht zu Oniumsalzen, sondern zur Spaltung der M–E‐Bindungen unter Bildung von π‐C5H5(CO)3MX (X I, Cl) und CH3ER2 bzw. R2ECCl2F. Für die Reaktivitätsabstufung als Funktion von ER2 bzw. M gilt: P(CF3)2 > P(CN)2 > As(CF3)2; Cr > Mo > W. Wegen der geringen Donorstärke der Komplexe 1a–c, 2a–c und 3a–c werden Zweikernverbindungen π‐C5H5(CO)3MER2W(CO)5 (E As, R CF3: 11a–c; E P, R CN: 12a–c; ER2 = P(CN)Ph: 13a, b) nur mit dem hochreaktiven W(CO)5THF erhalten. Bei den (CF3)2P‐verbrückten Derivaten führt spontane CO‐Abspaltung zu den Dreiringsystemen (10a–c) mit M–W‐Bindung.
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