Topography of the subunits of Micrococcus lysodeikticus F1-ATPase

Summary The combined use of proteolytic digestion and lactoperoxidase catalyzed labelling with [¹²⁵I] applied to membrane-bound or soluble pure F₁-ATPase from Micrococcus lysodeikticus has allowed us to establish the topography of its , , and subunits within the protein molecule and with respect to the plane of the membrane.The subunit is most externally located to the membrane bilayer looking towards the cytoplasmic face, a position consistent with its proposed catalytic role. The and subunits lie in an intermediate layer between the subunits and the membrane, in which the subunit occupies a central position within the F₁-ATPase molecule in contact with the subunit. The subunit appears to be tightly bound to the F₀ component of the ATPase complex, probably buried in the membrane bilayer. A molecular arrangement of M. lysodeikticus ATPase is proposed that, taking into account the subunit stoichiometry _{3 3 2 2} (MW 420 000), accommodates the role assigned to each subunit and most, if not all, the known properties of this bacterial energy-transducing protein.     

Biosynthesis of (1,3)(1,4)-β-glucan and (1,3)-β-glucan in barley (Hordeum vulgare L.)

Mixed membrane preparations from the coleoptiles and first leaves of young barley (Hordeum vulgare L. cv. Triumph) plants catalysed the synthesis of 55% methanol-insoluble labelled material from UDP[U-¹⁴C]glucose, the main components of which were identified as (1,3)(1,4)-- and (1,3)--D-glucans. The membrane preparations also catalysed the transformation of UDP-glucose into labelled low-molecular-weight products, mainly glucose (by phosphatase action), glucose-1-phosphate (by phosphodiesterase action) and glyco(phospho)lipids (by glycosyltransferase action). The formation of (1,3)(1,4)--glucans, (1,3)--glucans, and the other reactions competing for UDP-glucose, were monitored simultaneously and quantitatively by a novel procedure based on enzymatic analysis, thin-layer chromatography and digital autoradiography. Thus it was possible (i) to optimise conditions to obtain (1,3)(1,4)--glucan synthesis or (1,3)--glucan synthesis in isolation, and (ii) to study the influence of temperature, pH, cofactors, substrate concentration etc. on the (1,3)(1,4) and (1,3)--glucan synthesis reactions even when both occurred together. The synthesis of both -glucans was optimal at 20°C. In Tris-HCl buffer, the pH optima for (1,3)(1,4)--glucan synthesis and (1,3)--glucan synthesis were pH 8.5 and pH 7.0, respectively. Both glucan-synthesis reactions required Mg²⁺: (1,3)--glucan synthesis was optimal at 2 mM, whereas (1,3)(1,4)--glucan synthesis continued to increase up to 200 mM Mg²⁺, when the ion was supplied as the sulphate. (1,3)--Glucan synthesis was Ca²⁺ dependent and this dependence could be abolished by proteinase treatment. The K _m with respect to UDP-glucose was 1.5 mM for (1,3)--glucan synthesis and approximately 1 mM for (1,3)(1,4)--glucan synthesis. The (1,3)(1,4)--glucan formed in vitro had the same ratio of trisaccharide to tetrasaccharide structural blocks irrespective of the experimental conditions used during the synthesis: its enzymatic fragmentation pattern was indistinguishable from that of barley endosperm (1,3)(1,4)--glucan. This indicates either a single synthase enzyme, which is responsible for the formation of both linkage types, or two enzymes which are very tightly coupled functionally.Abbreviations G4G4G3G Glc(1,4)Glc(1,4)Glc(1,3)Glc (-linked) - UDP-Glc uridine-5-diphosphate glucose We are grateful to the Commission of the European Communities for the award of Training Fellowships to Christine Vincent and Martin Becker.     

Genetic Determination of Mental Activity Parameters in the Families of Schizophrenia Patients

Psychological parameters of mental activity (30 in total) and their genetic determination were studied in 67 families of schizophrenia patients (67 patients, 107 parent, and 30 sibs). Abnormalities of most of the examined characteristics were found in both the patients and their healthy relatives. Parameters of attention shifting and emotionality revealed the largest genetic component (25–75 and 17–98%, respectively) in all analyzed groups of relatives (probands–affected sibs, probands–healthy sibs, healthy parents–healthy children, affected parents–affected children). Significant impact of genetic factors was also found in parameters stability of attention under conditions of continuous concentration, mediated retention span productivity of voluntary retention by reproduction data, personal anxiety level, reflection of unusual social groups, and self-assessment. The relationships among the characteristics examined in the system of mental activity were established by means of cluster analysis. The results of this study can be used in medical genetic counseling for identifying subjects at high risk for schizophrenia.     

Molecular screening and fetal diagnosis of β-thalassemia in the Italian population

Summary This paper reports our experience of molecular screening and fetal diagnosis of -thalassemia in 457 at risk couples of Italian descent. Molecular screening was carried out by dot blot analysis on amplified DNA with oligonucleotide probes complementary to the eight most common mutations in Italians [39 (CT); 6 (-A); ⁺-87 (CG); ⁺ IVSI nt 110 (GA); IVSI nt 1 (GA); ⁺ IVSI nt 6 (TC); IVSII nt 1 (GA); ⁺ IVSII nt 745 (CG)]. By using this approach, we have been able to define the mutation in 92.8% of cases. The rest (all but four) were defined by direct sequencing and this led to the detection of nine rare mutations [76 (-C); ⁺ IVSI nt 5 (GA); ⁺ IVSI nt 5 (GC); ⁺ IVSI -1 (cod 30) (GC); ⁺-87 (CT), -290 bp del.; ⁺-101 (CT)], and to the characterization of a novel mutation consisting of the deletion of the G at the invariant AG of the IVSII splice acceptor site of the -globin gene ( IVSII nt 850-1 bp). In the remaining four cases, the -globin gene showed entirely normal sequences and the -globin gene cluster was intact, as indicated by Southern blot analysis. Fetal diagnosis was carried out by dot blot analysis with the oligonucleotide probes defined in the parents. The procedure is simple and reliable, and the results can be obtained within 1 week of sampling. No misdiagnosis has so far occurred. The results indicate that fetal diagnosis of -thalassemia by DNA analysis may be obtained in practically all cases (even in a population showing marked heterogeneity of -thalassemia) by the combination of dot blot analysis for detecting common mutations, and direct sequencing for defining those that are uncommon.     

Synthesis of non-proteinogenic (D)- or (L)-amino acids by asymmetric hydrogenation

Summary Non-proteinogenic amino acids play an increasing role in oligopeptide chemistry. Their pharmacological and chemical properties, caused by D-configuration and unnatural residues, are more and more used for drug design. Different methods of asymmetric synthesis have been developed during the last decade to prepare unusual amino acids. One of them, the asymmetric hydrogenation of dehydroamino aids catalyzed by chiral rhodium (I) complexes, will be described. A series of examples, D- and L-configured, like naphthyl-, thienyl-, furyl-, and pyridylalanines, as well as phenylalanines substituted by chlorine, fluorine, p-nitro, p-methyl, p-trifluoromethyl, p-isopropyl, and p-tert-butyl have been prepared and characterized. Some analytical data like melting points and values of optical rotation are summarized in tables.Abbreviations (–)-DIOP (4R,5R)-4,5-Bis(diphenylphosphinomethyl)-2,2-dimethyl-1,3-dioxolane - (–)-BPPM (2S,4S)-N-tert-Butoxycarbonyl-4-diphenylphosphino-2-diphenylphosphinomethyl-pyrrolidine - Ph--glup Phenyl 4,6-O-(R)-benzylidene-2,3-O-bis(diphenylphosphino)--D-glucopyranoside - DuPHOS 1,2-bis-(phospholano)benzene - PROPRAPHOS 2,3-O,N-bis(diphenylphosphino)-1-(naphthoxy)-2-hydroxy-3-isopropylamino propane - PINDOPHOS 2,3-O,N-bis(diphenylphosphino)-1-(4-indolyloxy)-2-hydroxy-3-isopropylamino propane     

T cells in murine lupus: propagation and regulation of disease

MRL/Mp-lpr/lpr mice develop a spontaneous lupus syndrome, including hypergammaglobulinemia, autoantibodies, glomerulonephritis, and lymphadenopathy. To investigate the role of lymphocyte subsets in the pathogenesis of disease, lupus-prone MRL mice deficient in T cells, T cells, or both were generated. Mice deficient in T cells developed a partially penetrant lupus syndrome, characterized by lymphadenopathy, elevated levels of class-switched immunoglobulins, an increased incidence of antinuclear antibodies, and immune deposits in kidneys which progressed to renal insufficiency over time. In comparison to wild type animals, T cell-deficient animals developed an accelerated and exacerbated disease phenotype, characterized by accelerated hypergammaglobulinemia and enhanced autoantibody production and mortality. Repertoire analysis of these latter animals identified polyclonal expansion (V) of CD4+B220-cells. Mice lacking both and T cells failed to generate class-switched autoantibodies and immune complex renal disease. First, these findings demonstrate that murine lupus in the setting of Fas-deficiency does not absolutely require the presence of T cells, and they also suggest that a significant basis for MRL/lpr disease, including renal disease, involves T cell-independent, T cell dependent, polyreactive B cell autoimmunity, upon which T cell-dependent mechanisms aggravate specific autoimmune responses. Second, these data indicate that T cells partake in the regulation of systemic autoimmunity, presumably via their effects on CD4+B220-T cells that provide B cell help. Finally, these results demonstrate that MRL/lpr B cells, despite their intrinsic abnormalities, cannot per se cause tissue injury without T cell help.Abbreviations snRNPs small nuclear ribonucleoprotein particles     

Different impacts of two species of aphid-attending ants with different aggressiveness on the number of emerging adults of the aphid’s primary parasitoid and hyperparasitoids

The impacts of two species of ants (Lasius niger and Pristomyrmex pungens) attending the cotton aphid (Aphis gossypii) on the number of emerging adults of the aphids primary parasitoid (Lysiphlebus japonicus) and hyperparasitoids were assessed experimentally at a no-pesticide mandarin grove. L.japonicus females were observed foraging frequently in aphid colonies attended by either ant species, with more females in P.pungens-attended than in L.niger-attended colonies, but rarely in aphid colonies where ants were artificially excluded. Females were less often attacked by P.pungens workers than by L.niger workers, so that they stayed longer and oviposited into more aphids in P.pungens-attended than in L.niger-attended colonies. Attendance by each ant species reduced predator numbers in aphid colonies, compared to colonies where ants were absent, although P.pungens was slightly less effective in repelling predators. Therefore, both ant species incidentally protected parasitized aphids from predators. Consequently, L.japonicus-mummies were abundant in colonies attended by either ant species, with more mummies in P.pungens-attended colonies, and were scarce in ant-excluded colonies. The hyperparasitism and predation on L.japonicus larvae within mummies occurred more frequently in P.pungens-attended than in L.niger-attended colonies, but mummy predation rate was only 20% in the former. As a result, the number of emerging L.japonicus adults did not differ significantly between aphid colonies attended by the two ant species, but significantly more hyperparasitoids emerged in colonies attended by the relatively less aggressive P.pungens than in colonies attended by L.niger.     

Interchange-trisomics in barley

Observations on morphology, sterility and cytology of some interchangetrisomics obtained from the progeny of radiation induced interchangeheterozygotes in a 6-rowed barley (Hordeum vulgare L.) var. K₁₂ are described. The different interchange trisomics show distinct phenotypic expression and have been classified as bushy, slender, robust, semi-erect and pseudonormal on the basis of their gross morphology, leaf characteristics, awn and spike lengths. All interchange trisomics show pollen and ovule sterility which varies between plants. Meiotic behaviour is described. The five different interchange trisomics appear to have different extra chromosomes.     

Light and GTP dependence of transducin solubility in retinal rods

The physical origin and functional significance of the near infra-red light scattering changes observable upon flash illumination of diluted suspensions of magnetically oriented, permeabilised frog retinal rods has been reinvestigated with particular attention paid to the degree with which transducin remains attached to the membrane. In the absence of GTP, the so called binding signal is shown to include two components of distinctive origins, widely different kinetics, and whose relative amplitudes depend on the dilution of the suspension and resulting detachment of transducin from the disc membrane. The fast component is a consequence of the fast interaction between photoexcited rhodopsin (R^*) and the transducin remaining on the membrane. Its kinetics monitors a structural modification of the discs caused by a change in electrostatic interaction between closely packed membranes upon the formation of R^*-T complexes. The slow component monitors the slow rebinding to the membrane and possible subsequent interaction with excess R^* of T-GDP which, in spite of its low solubility, had eluted into solution given the high dilution of the permeated rods. In the presence of GTP, the so called dissociation signal includes a fast, anisotropic release component that specifically monitors the release into the interdiscal space of T -GTP formed from the membrane-bound pool, and a slower isotropic loss component monitoring the leakage from the permeated rod of the excess T -GTP which did not interact with the cGMP phosphodiesterase. The amplitudes of both components depend exclusively on the membrane bound T-GDP pool. The kinetics of the loss component is limited by the size and degree of permeation of the rod fragments, rather than by the dissociation rate of T -GTP from the membrane.Abbreviations ROS rod outer segment - R rhodopsin - R^* photoactivated rhodopsin - T, T-GDP, T -GDP, T -GTP, T transducin and its various forms - T _mb, T _sol: T bound to membrane or soluble - PDE cGMP-phosphodiesterase - GTP guanosine 5-triphosphate - GDP guanosine 5-diphosphate - GDP S guanosine 5-O-(2-thiodiphosphate) - cGMP guanosine-3-5 cyclic-monophosphate - DTT dithiothreitol - HEPES 4-(2-hydroxyethyl)-1-piperazine-ethane sulfonic acid - TRIS Tris (hydroxymethyl)aminomethane - SDS sodium dodecyl sulfate     

Problems in estimating growth rates of marine phytoplankton from short-term14C assays

Growth rate estimates () of phytoplankton populations that were sampled from nitrogen-limited continuous cultures and then incubated for short durations in batch culture with added¹⁴C-HCO₃ ^– were significantly different than steady-state growth rates () for 3 of 5 marine phytoplankton species. Two diatoms,Thalassiosira weissflogii andChaetoceros simplex, displayed virtually identical growth rates (=) over a wide range of, whereas for a third diatom,Phaeodactylum tricornutum, was overestimated by an average of 40% compared to. In contrast, was underestimated by the¹⁴C technique for the two remaining species: up to 40% at a steady-state of 1.0 day^–1 for the chlorophyteDunaliella tertiolecta and up to 100% at of 1.4 day^–1 for the haptophytePavlova lutheri. For the latter two species the divergence between and appeared to increase with increasing steady-state. A simple model of labeled and total carbon flow between the aqueous phase and cellular biomass was constructed to demonstrate that respiration was negligible when=, but was significant when>. In the cases in which<, a rapid physiological alteration presumably took place once the steady state was disturbed and cells were placed in the incubation chambers, which perhaps was related to the nutritional state of the cultures at the time of sampling. Questions thus are raised regarding our ability to measure accurately primary productivity from shipboard experiments with confined samples of phytoplankton from nutrient-impoverished waters that probably are less hardy than the laboratory cultures used in these studies.     

Zur Paarbildung der Uferschwalbe (Riparia riparia)

Zusammenfassung Uferschwalben kehren aus den afrikanischen Winterquartieren in Trupps beiderlei Geschlechts zurück. Erste Beringungsergebnisse belegen, daß zunächst mehrjährige, vermutlich untereinander bekannte Vögel eintreffen, die den Brutplatz aus vergangenen Brutperioden her kennen. Die Masse der später ankommenden Vögel dürfte weitgehend aus einjährigen oder ortsfremden Uferschwalben bestehen, die sich größtenteils erst während der Paarbildung persönlich kennenlernen. Der anfängliche Schwarmzusammenhalt der nacheinander eintreffenden Trupps führt zur Bildung von Subkolonien, die für Brutplätze ab einer bestimmten Größenordnung typisch sind. Uferschwalben- gründen nacheinander mehrere Reviere, d. h. sie besetzen Steilwandbereiche, in denen sie ausschließlich mit den Füßen eine Röhre oder Mulde graben, singen und Bogenflüge starten. Bis auf singende oder bekannte werden Artgenossen im Revier geduldet. Uferschwalben- suchen besetzte Reviere auf. Ohne Röhrenbindung verhalten sie sich still und unauffällig, ihre Grabungsaktivitäten sind von untergeordneter Bedeutung. Die Bindung an ein bestimmtes Revier entwickelt sich individuell verschieden und entscheidet über den Abschluß des Röhrenbaues (Herstellung der Nistkammer). Reviere ohne dauerhafte -Bindung werden von den aufgegeben. Aktivitäten, die auf wachsende Revierbindung eines hindeuten, sind: häufige oder/und länger dauernde Aufenthalte des in einem besetzten Revier und sporadisches Mitgraben; aggressives Verhalten gegenüber Artgenossen (i. d. R. fremde ), die im Revier landen wollen; gemeinschaftlicher, leiser Gesang von und im Röhrenbereich. Aktivitäten, die für eine vollzogene Paarbildung sprechen, sind: Fertigstellen der Röhre durch Grabung der Nestkammer; längere gemeinsame Aufenthalte innerhalb und außerhalb der Röhre; Voranfliegen des beim Röhrenanflug; Übernachten von und in der Röhre; Nestbau; ausdauernde Verfolgungsflüge während der Kopulationsphase. Die Paarbildung ist demnach ein individueller Prozeß, bei dem die Aktivitäten der im Revier als Werbung, die der als Revierwahl interpretiert werden.

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On pair-formation in the Sand Martin,Riparia riparia

Summary European Sand Martins arrive at their breeding sites in flocks of usually unmated and . Ringing results of a large population in NW-Germany and own observations indicate that the first flocks about a dozen individuals with an approximately balanced sex ratio appear at traditional breeding places and consist of older, experienced resident birds (presumably acquainted with one another). The birds arriving over the next several weeks are mainly first-year or non-resident individuals. The flocks arrive separately in areas with suitable sandcliffs, synchronize the pair-formation activities and avoid disturbances among paired and unpaired birds. This behaviour causes the formation of subcolonies, which are typical for all densely occupied breeding places. Each settles on a fixed area on the sandcliff (territory) in order to excavate a burrow, to sing the territory-song (fig. 2 b) and to perfor the territory-circle-flight (fig. 2 c, 4 a). Silent birds (normally ) are welcomed or tolerated by the resident . The sexes are monomorphic and therefore courtship displays of the are non-aggressive until establishment of pair-bonds. Only intruding singing or individually known neighbouring are driven away, usually at early stages of territory occupation. Unmated are normally shy and very sensitive to protracted disturbances. visit several occupied territories of the colony (fig. 1–3) in order to choose a burrow. leave territories which do not attract a . They settle new territories on the sandcliff, causing a surplus of burrows compared to breeding pairs in the colony. Activities which indicate the development of pair-bonds are: regular visits of a to a particular occupied territory with sporadic excavations by the ; aggressive activities of the towards other visitors usually , but sometimes at first even against the resident (i. e.: vocal threats, bill-gaping, pecking or pushing with the bill or vigorous face-to-face fights, fig. 3 b, 3 c). and sing the soft mating song at or in the burrow (fig. 1 c). Activities which indicate completed pair-bonds are: completion of the burrow by digging the nestchamber, predominantly done by the ; both birds staying together over long periods, both inside and outside the burrow; invitation-flight by the (fig. 4 b); and spending the night together in the burrow; beginning of nest-building, first only by the , then by both birds and finally only by the , accompanied by the (guarding-flight;, fig. 4c); mate-pursuit flights (sexual chases) during copulation phase, in which the singing pursues the silent , often accompanied by other (cp. fig. 4 d). Pair-formation in the Sand Martin occurs on individual territories and not, according toHickling (1959), within the flock.

     

AMP synthesis in aqueous solution of adenosine and phosphorus pentoxide

Possible formation of a P₄O₁₀ molecule in magma, the stability of the molecule in hydrous volcanic gas at high temperatures and a possible prebiotic phosphate cycle were discussed in relation to chemical evolution. To demonstrate the utility of phosphorus pentoxide as a phosphorylating agent, aqueous solutions of adenosine (0.02M) and phosphorus pentoxide (0.2M) were incubated at 37°C for 5 months. The pH of the solutions was adjusted every day or every few days to each fixed value (9.0, 10.5, 11.5, 12.5) with 10 N NaOH. The HPLC analysis showed the formation of 2-AMP, 3-AMP, 5-AMP, cyclic (2–3)-AMP and cyclic (3–5)-AMP. The main components of the products were 2- and 3-AMP, though cyclic (2–3)-AMP was the main component in the early period of the incubation at pH 9.0. The yields (conversion rate of adenosine to AMPs) were increased almost linearly with the incubation time for 5 months in the case of pH 9.0. The final yields were about 3% (pH 9.0), 6% (pH 9.0, 1 M NaCl), 5% (pH 9.0, 0.01 M CaCl₂, 0.01 M MgCl₂), 7% (pH 9.0, 0.5 M NaCl, 0.01 M CaCl₂, 0.01 M MgCl₂), 9% (pH 9.0, 1 M NaCl, 0.01 M CaCl₂, 0.01 M MgCl₂), 32% (pH 10.5), 43% (pH 11.5), 35% (pH 12.5).     

Rate of free-radical oxidation of C18 diene and triene fatty acids in aqueous micellar solutions and effectiveness of beta-carotene as an inhibitor of their oxidation

The rate of accumulation of conjugated dienes of polyunsaturated fatty acids was measured during free-radical oxidation of linoleic acid (18:2n-6, LA), -linolenic acid (18:3n-3, -LNA), and -linolenic acid (18:3n-6, -LNA) initiated by 2,2"-azo-bis-(2-amidinopropane) hydrochloride in aqueous micellar solutions of sodium dodecyl sulfate and sodium cholate. It was shown that, unlike homogeneous solutions, the oxidative stability of PUFAs in aqueous dispersions increased with an increase in the extent of unsaturation. The rate of LA oxidation was more than tenfold greater than that of - and -LNA. The antioxidant activity of -carotene, in contrast to homogeneous solutions, in both micellar systems studied depended on the degree of PUFA unsaturation. We found that 5 M -carotene effectively inhibited the LA oxidation (almost by 90%), whereas the oxidation of -LNA and -LNA was not inhibited by -carotene even at much greater concentration (30 M). The paradoxical discrepancy between the extent of unsaturation and the PUFA oxidation rate, as well as a decrease in the efficiency of -carotene-dependent inhibition of oxidation of more polyunsaturated fatty acids in reactions conducted in aqueous dispersions is consistent with the model according to which the peroxyl radicals of LA and fatty acids with the doublebond number greater than two exhibit different polarity.     

Existence and uniqueness of a sharp travelling wave in degenerate non-linear diffusion Fisher-KPP equations

In this paper we use a dynamical systems approach to prove the existence of a unique critical value c ^* of the speed c for which the degenerate density-dependent diffusion equation u _ct = [D(u)u _x ] _x + g(u) has: 1. no travelling wave solutions for 0 < c < c ^*, 2. a travelling wave solution u(x, t) = (x - c ^* t) of sharp type satisfying (– ) = 1, () = 0 ^*; '(^*–) = – c ^*/D'(0), '(^*+) = 0 and 3. a continuum of travelling wave solutions of monotone decreasing front type for each c > c ^*. These fronts satisfy the boundary conditions (– ) = 1, '(– ) = (+ ) = '(+ ) = 0. We illustrate our analytical results with some numerical solutions.     

The structure of the incompatibility factors of Schizophyllum commune: Constitution of the three classes of B factors

Summary The B factors of Schizophyllum commune are of 3 classes: The high recombining class I has 7 alleles and 7 alleles; the low recombining classes are class II with 7 allels and probably 2 alleles and class III with probably 2 (or also 2) alleles and 7 allels. A fourth hypothetical class (-) was not found and either does not exist or is indistinguishable from class III by the tests employed. The and alleles differ from and by either (a) mutations affecting both mating specificity and recombination frequency, or (b) deletions involving most of the B region.The research was supported by a grant from the Atomic Energy Commission of the U.S. No. (30-1)-3875 and was performed at the Biological Laboratories, Harvard University, Cambridge, Mass., U.S.A.     

Keratella mexicana sp. nov., a new planktonic rotifer from Aguascalientes,Mexico

A new species of Keratella is described from a small reservoir in Aguascalientes, Mexico. The species appears related to K. slacki Brziss, 1963 and K. lenzi Hauer, 1953.     

Der eilegeapparat der odonaten

Zusammenfassung Der Eilegeapparat mit drei Paar Gonapophysen wind als der ursprünglichste angesehen und vollständiger Eilegeapparat genannt; alle Typen mit weniger als drei Gonapophysenpaaren sind von ihm durch Rudimentation abzuleiten und werden als unvollständiger Eilegeapparat zusammengefaßt.Am vollstandigen Eilegeapparat sind seine Teile durch Gelenke und Muskeln beweglich, am unvollstandigen sind sie starr ; Gelenke und Legemuskeln fehlen. Die fur die Eiablage wichtigen Gelenke und Muskeln werden beschrieben.Die Entwicklung des vollstandigen Eilegeapparates erfolgt bei der Larve in der Reihenfolge, daß zuerst die Gon. laterales, hierauf die mediales und zuletzt die anteriores ausgebildet werden. Die Rudimentation des unvollstandigen geschieht in der gleichen Reihenfolge, indem zuerst die Gon. laterales und als letzte die anteriores zurück-gebildet worden.Die Eiablage erfolgt beim vollstandigen Eilegeapparat primär exophytisch durch Ablage auf dem Boden oder endophytisch durch Einstechen in Pflanzengewebe, beim unvollstandigen Eilegeapparat exophytisch durch Ablage in das Wasser.Es wind angenommen, daß die primär exophytische Ablageart die ursprünglichste ist und alle anderen von ihr abzuleiten sind.Die endophytische Ablage entwickelt an den Gonapophysen verschiedene Anpassungen, die exophytische führt zu ihrer Rudimentation.Anpassungen an die endophytische Ablage sind Verkürzung der Gonapophysen, Entwicklung eines Tastapparates (Styli), eines Schneide-apparate (Gon. mediales), einer Legeröhre (Gon. anteriores) und einer Stützkante an den Gon. laterales, Ablage in Gonaphysenstellung, oder am 10. Sternit, Ablage in Sternitstellung.Ablage in Gonapophysenstellung beansprucht die Gon. laterales und führt bei Ablage in ein Substrat von zunehmender Härte - sie erfolgt in extremen Fallen in Baumstämme — zu verschiedenen Modifikationen ; Ablage in Sternitstellung läßt die Gon. laterales unbeansprucht und könnte bei Ablage in ein Substrat von abnehmender Härte — sie erfolgt in extremen Fallen in Schlamm — zu Rudimentation der Gon. laterales und exophytischer Ablage in das Wasser überleiten.Der unvollständige Eilegeapparat zeigt eine große Formenmannigfaltigkeit, die sich aber auf zwei Grundtypen, einem mit zwei Paar Gonapophysen — es fehlen die Gon. laterales — und einem mit einem Gonapophysenpaar, der Scheidenklappe, einem Rudiment der Gon. anteriores, zurückführen lassen.Der Zweigonapophysentypus ist bei verschiedenen Gruppen erhalten; bei den Cordulegasterinae ist er morphologisch einheitlich, was einen Stillstand des Rudimentationsprozesses andeutet, und an eine bestimmte Eiablageart angepaßt; bei den anderen Gruppen ist er morphologisch sehr verschieden, wobei es sich wohl um verschiedene Rudimentationsstufen handelt, und fur die Eiablage funktionslos geworden.Der Scheidenklappentypus findet sich bei den Gomphidae, Corduliidae und Libellulidae. Ursprünglichere Formen zeigen längere, höher entwickelte, kürzere Scheidenklappen. Bei vielen Arten ist die Scheidenk1appe restlos rudimentiert. Ihre Rolle für die Eiablage ist fraglich, vielleicht nur sinnesphysiologischer Art. Mechanisch zu deutende Formen (Spitzhammerbildung) kommen vor und sind gelegentlich mit Eiablage auf dem Boden verbunden, was als Anklänge an eine primär exophytische Ablage gedeutet wird.Bei den Libellulidae werden vereinzelt sekundäre Apparate aus neuen Elementen entwickelt.Die Eizahl ist bei Formen mit vollständigem Eilegeapparat höher als bei Formen mit ,unvollständigem und bei den Corduliidae und Libellulidae am höchsten.Die morphologische Vielfalt der Eilegeapparate ist das Ergebnis von zwei Verhaltensänderungen, dem Üborgang der Imagines zu einer Ablage durch Einstechen in Pflanzengewebe und dem Übergang der Larven zum Leben im Wasser. Diese Änderungen wurden von den einzelnen Gruppen auf verschiedene Weise und in verschiedenem Ausmaße vollzogen und ließen eine Unzahl von morphologischen Typen entstehen.Das Bestreben, die Eier möglichst nahe dem Wasser abzulegen, führte jene Gruppen, die nicht oder nicht zu weit an die Ablage in Pflanzengewebe angepaßt waren, zur Ablage in das Wasser. Diese Ab lageart führte zur Rudimentation der Gonapophysen und ließ möglicherweise neue, der neuen Ablageart angepaßte Apparate entstehen.Die Rudimentation der Gonapophysen ermöglichte eine Erhöhung der Eizahl und führte these Gruppen zur Besiedlung von neuen Lebensräumen und damit zu ihrer heute dominierenden Stellung innerhalb der Ordnung.     

C(alpha) chemical shift tensors in helical peptides by dipolar-modulated chemical shift recoupling NMR

The C chemical shift tensors of proteins contain information on the backbone conformation. We have determined the magnitude and orientation of the C chemical shift tensors of two peptides with -helical torsion angles: the Ala residue in G*AL (=–65.7°, =–40°), and the Val residue in GG*V (=–81.5°, =–50.7°). The magnitude of the tensors was determined from quasi-static powder patterns recoupled under magic-angle spinning, while the orientation of the tensors was extracted from C–H and C–N dipolar modulated powder patterns. The helical Ala C chemical shift tensor has a span of 36 ppm and an asymmetry parameter of 0.89. Its ₁₁ axis is 116° ± 5° from the C–H bond while the ₂₂ axis is 40° ± 5° from the C–N bond. The Val tensor has an anisotropic span of 25 ppm and an asymmetry parameter of 0.33, both much smaller than the values for -sheet Val found recently (Yao and Hong, 2002). The Val ₃₃ axis is tilted by 115° ± 5° from the C–H bond and 98° ± 5° from the C–N bond. These represent the first completely experimentally determined C chemical shift tensors of helical peptides. Using an icosahedral representation, we compared the experimental chemical shift tensors with quantum chemical calculations and found overall good agreement. These solid-state chemical shift tensors confirm the observation from cross-correlated relaxation experiments that the projection of the C chemical shift tensor onto the C–H bond is much smaller in -helices than in -sheets.     

Pleiotropic transport mutants of Escherichia coli lack porin, a major outer membrane protein.

Summary Four pleiotropic transport mutants of Escherichia coli B/r with decreased affinity for the uptake of most nutrients were found to lack a major outer membrane protein of 36,500 daltons (porin) previously shown to produce transmembrane diffusion channels in in vitro reconstitution experiments. Consequent decrease in outer membrane permeability was confirmed by measuring the transmembrane diffusion rate of 6-aminopenicillanic acid. Quantitative considerations on the porin-dependent permeability of the outer membrane show that (a) there may be very large differences in the actual rates of penetration, even among the permeable substances and (b) the numbers of porin molecules present in wild type cells is several orders of magnitude higher than that necessary for the uptake of rapidly diffusing substrates such as glocose from ordinary culture media. The absence of porin and the pleiotropic transport defect were always contransduced, and the mutation was mapped at 73.7 min between aroB and malT by P1 transduction. When revertants able to grow on low concentrations of lactose were selected, in addition to true revertants suppressor strains with increased amounts of non-porin membrane proteins were isolated.This paper corresponds to paper XVI of the series dealing with the bacterial outer membrane from the laboratory of H.N. The preceding paper in the series is Nikaido, Bavoil, and Hirota, J. Bacteriol., in press