Showing papers in "Archives of Microbiology in 1968"

Acetylene reduction by nitrogen-fixing blue-green algae.

Abstract: Known nitrogen-fixing species of blue-green algae are capable of reducing acetylene to ethylene, but acetylene is not reduced by Anacystis nidulans, which does not fix nitrogen. Cycad root nodules which contain blue-green algae as endophytes reduce acetylene. Acetylene reduction is inhibited by carbon monoxide. Nitrate or ammonium-nitrogen has no immediate effect on algae reducing acetylene, but algae grown on nitrate-nitrogen gradually lose their capacity to reduce acetylene. Nitrate-nitrogen also inhibits heterocyst formation in these algae and there is a fairly direct correlation between the abundance of heterocysts in a particular sample and its capacity to reduce acetylene. Aphanizomenon flosaquae reduces acetylene and fixes nitrogen in unialgal culture and there is strong presumptive evidence that these reductions are carried out by the alga rather than by associated bacteria. The molar ratios of ethylene: ammonia produced vary within the range 1.4–1.8.

Electron microscopy of polyphosphate bodies in a blue-green alga, Nostoc pruniforme

Abstract: Preparations of the blue-green alga, Nostoc pruniforme, treated according to the lead-sulfide staining technique of Ebel et al. (1958b) were examined by light and electron microscopy. They were found to contain spherical, electron-dense bodies, generally in close association with the nucleoplasm and polyhedral bodies, and sometimes enclosed by a membrane. In preparations extracted with cold TCA prior to the application of the staining procedure, such electron-dense structures could no longer be found; electron microscopy revealed instead spherical, electron-transparent areas with an electron-dense periphery in positions generally occupied by the electron-dense bodies in preparations not extracted with TCA.

Studies on the biochemistry and fine structure of silica shell formation in diatoms. IV. Fine structure of the apochlorotic diatom Nitzschia alba Lewin and Lewin.

Abstract: The fine structure and pigmentation of an apochlorotic diatom isolated from decaying Macrocystis pyrifera is described. The morphology of acid cleaned shells suggests that the isolate is Nitzschia alba Lewin and Lewin. Light microscope observations indicated a centrally located nucleus and numerous highly refractile bodies which stained differentially with Nile blue and Sudan black B. The stained globules could be correlated in thin-sectioned profiles with either electron dense or lucent areas depending on the fixation technique. In the electron microscope the nucleus, Golgi complex, and mitochondria were similar in appearance to those described for other diatoms. Proplastid-like organelles, delimited by a double membrane, and containing small vesicles were also observed. Neither carotenoids nor chlorophylls could be detected by spectroscopic or spectrofluorometric analysis in vivo or in organic solvent extracts. Deposition of new walls was initiated by formation of silicon deposition-vesicles in the central region of dividing cells. The acentric raphes were deposited last. The genesis and interrelationship of the old plasmalemma, silicalemma, and newly formed plasmalemma are discussed.

Sekundär-Carotinoide in Grünalgen

Abstract: 1. Sekundar-Carotinoide (SC) sind Carotinoide, die in Organismen oder in ihren Organen meist gegen Ende ihrer Entwicklungsperioden an Stelle oder in Erganzung der primaren, normalerweise vorhandenen Carotinoide synthetisiert werden. 2. Bei den SC handelt es sich bevorzugt um Oxoderivate des β-Carotins: 3,3′-Dioxi-4,4′-dioxo-β-carotin (Astaxanthin); 3-Oxi-4,4′-dioxo-β-carotin; 4,4′-Dioxo-β-carotin (Canthaxanthin); 3-Oxi-4-oxo-β-carotin; 4-Oxo-β-carotin (Echinenon). Die Oxi-Polyene sind im nativen Zustand verestert. 3. 164 Stamme aus der Klasse derChlorophyta (148 Chlorococcale, 15 Volvocale, 1 Siphonale) wurden auf ihre Fahigkeit untersucht, SC zu bilden (vgl. Tab. 1) 4. Die SC werden vermutlich innerhalb der Chloroplasten synthetisiert. Synchron dazu verlauft die Bildung fetter Ole. Die SC difundieren in die Fettvacuolen und werden verestert. 5. Die Algen haufen SC bei vermindertem Stoffwechsel, insbesondere bei N-Mangel an. Diese Fahigkeit ist artspezifisch und unabhangig von den Kulturbedingungen (z.B. von der N-Quelle). N-Mangelalgen bauen bei Zusatz von N die SC wieder ab und die primaren Pigmente erneut auf. 6. Licht beeinflust die Biogenese der SC nur indirekt uber die Steigerung des Stoffwechsels. 7. Zusatze von Kohlenhydraten, Acetat, Pyruvat und Succinat erhohen die Konzentration an SC nicht. Der Einflus dieser Substanzen auf die SC-Bildung ist indirekt. Sie steigern das Wachstum, so das die N-Quelle schneller verbraucht wird. Infolgedessen setzt die Synthese der SC fruher als in Normalkulturen ein.

On the ATP generation by Chromatium in darkness.

Abstract: In Chromatium strain 6412 storage carbohydrate synthesized in the light, gradually disappeared in the dark. Simultaneously, poly-β-hydroxybutyric acid (PHB) was produced, CO2 was released and intracellular elemental sulfur was reduced to sulfide. Expressed on a molar base, the ratio between storage carbohydrate monomer (as glucose) consumed, sulfur reduced, PHB monomer produced, and sulfide released was approximately 1 : 3 : 1 : 3. This indicates that sulfur acts electron acceptor in the conversion of storage carbohydrate to PHB. Assuming that in the dark storage carbohydrate is broken down to pyruvate via the Embden-Meyerhoff pathway, whereafter PHB is synthesized from pyruvate via acetyl-CoA and acetoacetyl-CoA, the conversion of storage carbohydrate to PHB results in a net gain of 3 ATP per glycosyl unit converted. Since Thiorhodaceae are photolithotrophs, these processes would provide the organisms with maintenance energy during dark periods. They also explain motility of Chromatium in the dark.

The fine structure of akinete formation and germination in Cylindrospermum

Abstract: Akinete formation and germination were studied in a species of Cylindrospermum using the electron microscope. The differentiation of a vegetative cell into an akinete is characterized by cell enlargement, sheath condensation, deposition of several spore envelope layers, including a dense fibrillar layer and deposition of large cyanophycin granules. The mature akinete in addition to the multilayered envelope retains internally a large number of cyanophycin granules, a photosynthetic thylakoid system, polyhedral bodies, lipid deposits and nucleoplasmic regions. Germination of the akinete can take place in several modes differing in detail. Most frequently the spore envelope remains intact and the germling which may or may not have divided emerges through a pore at one end of the envelope. The photosynthetic thylakoid system appears to increase by the fusion of small vesicles found in the cytoplasm. Alpha-granules are numerous and cyanophycin is nearly absent in the germling.

Feinbau und Carotinoide von Tribonema (Xanthophyceae)

Abstract: Zell-Feinbau und Carotinoidausstattung wurde bei drei Arten der Xanthophyceengattung Tribonema untersucht: Tr. viride (Freilandmaterial), Tr. aequale und Tr. minus (Kulturmaterial). Wahrend die beiden letzteren nur einen Kern je Zelle enthielten, traten bei Tr. viride bis zu sechs Kerne je Zelle auf. Wahrscheinlich handelte es sich dabei um Faden, die im Begriff waren, Zoosporen zu bilden, was auch durch das vereinzelte Auftreten von Geiseln nahegelegt wird.

Fine structure of the mesosome and nucleoid in frozen-etched Bacillus subtilis.

Abstract: An electron microscopical investigation ofBacillus subtilis prepared by freeze-etching revealed the fine structural changes that occur in the cell prior to spore formation. The initiation of growth from lyophilized cells was characterized by the appearance of numerous vesicular structures embedded in and attached to the plasma membrane. As growth continued, the number of vesicular structures decreased and lamellar membrane structures began to appear. Prior to spore formation, a fine, fibrillar material was found in the central portion of the cell and was believed to be the DNA.

[Regulation of glucose-6-phosphate dehydrogenase from Hydrogenomonas by ATP and reduced pyridine nucleotides].

Abstract: 1 Die Bildung der zum Fructoseabbau uber den Entner-Doudoroff-Weg dienenden Enzyme wird in Hydrogenomonas H 16 durch molekularen Wasserstoff reprimiert In volladaptierten, auf Fructose gewachsenen Zellen wird der Fructoseabbau durch H2 gehemmt Die durch H2 bewirkte Hemmung greift wahrscheinlich an der Glucose-6-phosphat-Dehydrogenase an 2 Die aus Hydrogenomonas H 16 100fach angereicherte Glucose-6-phosphat-Dehydrogenase unterscheidet sich vom Hefeenzym durch ihre geringe Substrataffinitat, durch die Fahigkeit sowohl mit NADP als auch mit NAD als Coenzym zu reagieren und durch den sigmoiden Verlauf der Substratsattigungskurve (G-6-P) 3 Das Enzym wird durch ATP und NADH2 gehemmt Durch ATP wird die Sigmoiditat der Substratsattigungskurve verstarkt Aus den gewonnenen kinetischen Daten ist zu schliesen, a) das die durch NADH2 bewirkte Hemmung vor allem auf einer Konkurrenzreaktion zwischen NADP und NADH2 um die Bindungsstelle des Coenzyms am Enzym beruht, b) das G-6-P-DH ein allosterisches Enzym ist, das aus mindestens vier Untereinheiten besteht und fur welches ATP ein negativer allosterischer Effector ist; c) das die Substratbindungsstellen fur G-6-P der Enzymuntereinheiten kooperative Wechselwirkungen aufeinander ausuben; d) das G-6-P-DH ein “K-System”, ist, d h das der allosterische Effector den apparenten K m -Wert,jedoch nicht die maximale Geschwindigkeit (vmax) der Enzymfunktion verandert 5 G-6-P-DH aus H 16 wird durch Magnesium-Ionen nicht aktiviert Hohe MgSO4-Konzentrationen hemmen das Enzym sogar Durch Zusatz von MgSO4 kann die “ATP-Hemmung” vollkommen aufgehoben werden, wenn G-6-P in hoher Konzentration im Reaktionsgemisch vorliegt Die Hemmung wird minimal, wenn das Verhaltnis Mg/ATP den Wert 1,3 ubersteigt

Hydrogenase in pea root nodule bacterioids.

Abstract: Hydrogen uptake has been shown to occur with pea root nodule breis and this uptake has been shown to be confined to the bacteriods. The uptake of hydrogen by washed bacteriods, in the absence of any added substrates, has been shown to be accompanied by oxygen uptake and the ratio of hydrogen uptake to oxygen uptake in these preparations has been found to be 2:1. Substrates, provided to washed bacteriods, inhibit the uptake of hydrogen and it has been found that the utilisation of substrates, as measured by carbon dioxide evolution, is inhibited by hydrogen. It is suggested that hydrogen and substrates compete for electron carriers and that electrons from the hydrogen reduce components of the electron transport pathway and ATP is produced.

Studies on marine occurring yeasts: Respiration, fermentation and salt tolerance

Abstract: The effect of various NaCl concentrations on respiration and fermentation rates in cells with or without added glucose as exogenous substrate as well as on respiratory quotients was determined for Debaryomyces hansenii, Saccharomyces cerevisiae, Cryptococcus albidus, and Candida zeylanoides, all yeasts isolated from marine environment. A given strain had about the same respiratory and fermentatory intensity at 0% and 4% NaCl (w/v). A further increase considerably reduced the oxygen uptake or CO2-evolution. D. hansenii was the most NaCl tolerant yeast tested, giving about 10% activity still at a concentration of 24% NaCl, whether the activities of whole cells or cell homogenates were determined. For S. cerevisiae or Cr. albidus the respiratory activity was reduced to about the same degree at 16% NaCl for whole cells, at 12% NaCl for homogenates of Cr. albidus. A somewhat higher NaCl concentration was evidently tolerated for respiration and fermentation than for growth, very obvious in the case of C. zeylanoides. The minimum values for water activity (a w) permitting 10% respiration activity were higher when produced by electrolytes (NaCl, KCl, or Na2SO4), lower when due to sugars (metabolizable glucose or non-metabolizable lactose) and lowest when due to glycerol. The a w per se was evidently not solely decisive for the limitation of respiration activity. Attempts were made to assess an effect of high NaCl concentrations on the glucose uptake. The potassium content was higher in cells of the highly halotolerant D. hansenii than in those of the other yeasts and decreased with the increase in external, consequently in internal, Na+ concentration. The decrease in K+ content can presumably only proceed to a certain extent, below which the ability for growth and respiration was lost.

Notes on the physiology of Botryococcus braunii Kützing

Abstract: 1. An unialgal clone of the colonial freshwater alga Botryococcus braunii was obtained and its growth in culture studied. 2. Pigments and other aspects of its chemical composition were examined. 3. Changes in chemical composition with age were followed. 4. Rates of endogenous respiration and the use of respiratory substrates were followed manometrically.

Inhibition of rhizobia by a strain of Rhizobium trifolii: Some properties of the antibiotic and of the strain

Abstract: An ineffective strain of Rhizobium trifolii, T24, produced an antibiotic active against other strains from several species of Rhizobium. The antibiotic was relatively stable to heat treatment below 90° C but was irreversibly inactivated by low pH and by unidentified microbial contaminants. Activity was readily destroyed by papain but not by trypsin, chymotrypsin, lysozyme, α-amylase, ribonuclease or deoxyribonuclease. The molecular weight of the active substance was estimated by gel filtration and dialysis procedures to be within the range of 1000 to 2000, probably at the lower end of this range. Growth inhibition of sensitive rhizobia appeared to occur mainly by bacteriostasis, and inhibition was reversible by some basic metabolites. Effective nodulation of clover seedlings by antibiotic-sensitive strains of R. trifolii was strongly suppressed by mixed inocula including T24. Predominance of ineffective symbiosis was apparently due to competitive advantage associated with antibiosis.

Electron microscopy of spore germination and cell wall formation in Mucor rouxii.

Abstract: The fine structure of ungerminated and aerobically germinated sporangiospores of Mucor rouxii was compared. The germination process may be divided into two stages: I, spherical growth; II, emergence of a germ tube. In both stages, germination is growth in its strictest sense with overall increases in cell organelles; e.g., the increase in mitochondria is commensurate with the overall increase in protoplasmic mass. Noticeable changes occurring during germination are the disappearance of electron-dense lipoid bodies, formation of a large central vacuole and, most strikingly, formation of a new cell wall. Unlike many other fungi, M. rouxii does not germinate by converting the spore wall into a vegetative wall. Instead, as in other Mucorales, a vegetative wall is formed de novo under the spore wall during germination stage I. This new wall grows out, rupturing the spore wall, to become the germ tube wall. Associated with the apical wall of the germ tube is an apical corpuscle previously described. The vegetative wall exhibits a nonlayered, uniformly microfibrillar appearance in marked distinction to the spore wall which is triple-layered, with two thin electron dense outer layers, and a thick transparent inner stratum. The lack of continuity between the spore and vegetative walls is correlated with marked differences in wall chemistry previously reported. A separate new wall is also formed under the spore wall during anaerobic germination leading to yeast cell formation. On the other hand, in the development of one vegetative cell from another, such as in the formation of hyphae from yeast cells, the cell wall is structurally continuous. This continuity is correlated with a similarity in chemical composition of the cell wall reported earlier.

Temperature functions of thermal death in yeasts and their relation to the maximum temperature for growth.

Abstract: Parameters of thermal death were determined in 10 strains of yeast species whose maximum temperatures for growth (T max) ranged from 22 to 49°C. Arrhenius plots of the specific thermal death rates (k d) formed a positional sequence at the level of the experimental points that corrresponded in all but one case to the sequence of the respective T max values. Extrapolated k d values at higher or lower temperatures no longer formed this sequence. The correlation of the temperature functions with T max could be characterized in terms of a new activation parameter, for which the name thermal death activation constant is introduced. It has the following form: T.D.A. $$constant = \frac{{\Delta {\rm H} e }}{{T_{\max + n} }}$$ − ΔS≠ where ΔH≠ and ΔS≠ are respectively the apparent heat and entropy of activation of thermal death and n is the number of degrees above T max (expressed in °K) at which the T.D.A. constant exists. Seven mesophilic yeasts had a T.D.A. constant between 72 and 79 calxmol-1 degree-1 at n values between 1 and 4°. This suggested that the destructive process that limits k d in these strains is of the same species as one that contributes to the establishment of T max. Two psychrophilic yeasts apparently had a similar T.D.A. constant but at a high n value (about 12.5°C) which suggested that in these strains T max is governed by a destructive process unrelated to the one that underlies thermal death. The strain of the nearly thermophilic Hansenula angusta (T max 49°C) did not fit in either group. The significance of the T.D.A. constant is discussed and expressions for ΔH≠ and ΔS≠ in terms of bond activation parameters are proposed.

Kleine Mitteilungen über Flagellaten und Algen

Abstract: Porphyridium marinum ist mit P. cruentum identisch. Weder morphologische, noch physiologische Unterschiede liesen sich finden. Die Alge kann ohne organische Verbindungen auskommen und bedarf keiner Vitamine, wird aber durch Erddekokt und Hefeextrakt gefordert.

Host range and infection cycle of a newly isolated strain of Bdellovibrio bacteriovorus

Abstract: Der neu isolierte Stamm W von Bdellovibio bacteriovorus infiziert und lysiert Rhodospirillum rubrum F und alle anderen untersuchten Athiorhodaceae, nicht aber Pseudomonas aeruginosa und Spirillum serpens. Er befallt auch zahlreiche Enterobacteriaceae und von den grampositiven Bakterien Streptococcus faecalis und Lactobacillus plantarum.

Growth measurements of Chromatium cultures

Abstract: The optical density of Chromatium cultures grown anaerobically in the light with sulfide as electron donor is mainly determined by the sulfur content of the cells. Since the sulfur content varies, growth cannot be followed in this way. However, optical density measurements are very useful to characterize the moment of sulfide depletion and maximal sulfur storage. In addition to protein or cell nitrogen, increase in structural cell material in growing cultures of Chromatium can easily be followed by bacteriochlorophyll determinations, provided that the illumination intensity is higher than the saturation intensity.

[Studies on the photoautotrophy in newly isolated non-sulfur purple bacteria with molecular hydrogen].

Abstract: In einer Mineralsalzlosung mit 0,1% NH4Cl und 0,01% Hefeextrakt wurden aus Schlammproben unter einer Atmosphare aus 90% H2 und 10% CO2 im Licht acht verschiedene Stamme von schwefelfreien Purpurbakterien angereichert und isoliert, die zum photoautotrophen Wachstum mit H2-CO2 befahigt sind. Die neuisolierten Stamme wurden aufgrund ihrer mikroskopischen Merkmale und ihrer Fahigkeit zur Verwertung verschiedener organischer C-Verbindungen bestimmt. Drei Rps. capsulata-Stamme benotigen Thiamin als Wachstumsfaktor, zwei R. rubrum-Stamme Biotin und ein Rps. gelatinosa-Stamm benotigt Thiamin und Nicotinsaure. Ein Rps. palustris-Stamm wachst langsam in einem Medium ohne Vitaminzusatz. Der Wachstumsfaktor-Bedarf eines zweiten Rps. palustris-Stammes kann nur durch Hefeextrakt gedeckt werden. Bei allen Stammen wird das Wachstum durch kleine Mengen (0,01%) Casaminosauren bzw. Hefeextrakt merklich beschleunigt. Die kurzesten Verdoppelungszeiten beim photoautotrophen Wachstum mit H2 weisen die drei Rps. capsulata-Stamme auf (17 bis 23 h in einem Mineralmedium mit Thiamin, 10,5–11 h in einem Mineralmedium mit 0,01% Hefeextrakt). Die Hydrogenase-Aktivitaten der Stamme sind in starkem Mase abhangig von der Anzucht der Zellen. Die niedrigsten Aktivitaten werden nach photoheterotropher Anzucht in einem Medium mit NH4Cl als N-Quelle gemessen, mittlere Aktivitaten nach photoheterotropher Anzucht in einem Medium mit Glutamat als N-Quelle und die hochsten Aktivitaten nach photoautotropher Anzucht mit H2-CO2. Die hochsten Raten der H2-abhangigen CO2-Fixierung werden ebenfalls nach photoautotropher Anzucht gemessen.

The classification of free-living spirochetes.

Abstract: The natural relationships among free-living and host-associated spirochetes were studied by investigating aspects of their morphology, physiology and DNA base composition. These studies indicated that the strictly and facultatively anaerobic, free-living spirochetes share characteristics which distinguish them from their host-associated counterparts and from the free-living leptospires.

A new genus of the Actinoplanaceae: Planobispora, gen. nov.

Abstract: A new species of a new genus of the Actinoplanaceae is described, for which the name Planobispora longispora gen. nov. sp. nov. is proposed. The organism is a typical mesophilic, aerobic actinomycete, producing a filamentous growth which is differentiated into a vegetative and an aerial mycelium. The new organism is characterized by the formation of sporangia only on the aerial mycelium and by containing a longitudinal pair of motile spores.

Calorimetric measurement of free energy utilization by Nitrosomonas and Nitrobacter.

Abstract: Calorimetric estimates of the utilization efficiency of the free-energy derived from substrate oxidation by cell suspensions of two nitrifying bacteria, Nitrosomonas and Nitrobacter, provided two ranges of values: 11 to 27% and 15 to 51%, respectively. About 15 to 30% of the utilized free-energy is used for driving endergonic reactions other than CO2 fixation, probably the synthesis of polyphosphates. The molar heat of substrate oxidation does not seem to be influenced by the age of cells harvested during growth or by the length of the incubation period during which cells have been kept in a buffer suspension in a starved condition. The loss of respiratory activity measured either by oxygen uptake or heat evolution in the presence of the specific substrate, nitrite or ammonium, decreases according to kinetics which are influenced by the aerobiosis of the suspension. The viability of the starved cells decreases in a way which is similar to that of the respiratory activity. It seemed impossible to obtain cells which had lost their viability but kept the ability to oxidize their substrate. Two inhibitors of the respiratory chain, quinacrine and cyanide, are without effect on the molar heat of substrate oxidation and consequently on the free-energy utilization efficiency. 2.4 dinitrophenol did decrease the rate of heat evolution during substrate oxidation at concentrations at which the rate of oxygen uptake was not depressed, with the consequences that free-energy efficiency was apparently increased.

Catabolic repression and enzyme repression by molecular hydrogen in Hydrogenomonas

Abstract: 1. Molekularer Wasserstoff verhindert bei Hydrogenomonas H16 die Adaptation and Fructose; die Bildung der Enzyme des Entner-Doudoroff-Abbauweges wird reprimiert. 58 geprufte Stamme von Knallgasbakterien verhielten sich ohne Ausnahme gleichartig. 2. Molekularer Wasserstoff verhindert bei autotroph gewachsenen Zellen von H16 die Adaptation nicht nur an Fructose, sondern auch an Gluconat, Fumarat, Citrat, Isovalerat, Asparagin, L-Leucin und einige andere Aminosaren. 3. Molekularer Wasserstoff beeinflust den Abbau der Fructose auf zweifache Weise: Erstens durch Repression der Synthese der zum Entner-Doudoroff-Weg gehorenden Enzyme und zweitens durch Hemmung des am Fructoseabbau beteiligten Enzymsystems. Diese Hemmung wirkt sich in vivo in einer Herabsetzung der Rate des Wachstums oder der Synthese von Poly-β-hydroxybuttersaure um 80% aus. 4. Hydrogenomonas H16 setzt auch Gluconat uber den ED-Weg um. Im zellfreien Extrakt auf Gluconat gewachsener Zellen liesen sich Gluconokinase und das Entner-Doudoroff-Enzymsystem (6-Phosphogluconsaure-Dehydrase und 2-Keto-3-desoxy-6-phosphogluconsaure-Aldolase) nachweisen. Die Adaptation autotroph gewachsener Zellen an Gluconat wird durch Wasserstoff ebenfalls unterdruckt. Die Funktion der in volladaptierten Zellen enthaltenen Enzyme des Gluconatabbaus wird nicht gehemmt. 5. Die Hemmung des Fructoseabbaus durch molekularen Wasserstoff beruht auf der Hemmung eines oder mehrerer Enzyme des ED-Weges, welche oberhalb der Eintrittsstelle des Gluconats in den ED-Weg liegen. Wahrscheinlich beruht die “Wasserstoff-Hemmung” auf der Hemmung der G-6-P-DH durch ATP bzw. NADH2. Im zellfreien Extrakt lies sich G-6-P-DH durch ATP bzw. NADH2 stark hemmen. Die Substratsattigungskurve hat einen sigmoiden Verlauf.

Fine structure of Ectothiorhodospira mobilis strain 8113 thylakoids: Chemical fixation and freeze-etching studies

Abstract: An electron microscopic examination of thin-sections of chemically fixed cells and of frozen-etched cell preparations of the marine photosynthetic bacterium Ectothiorhodospira mobilis has been carried out. The morphology of cells grown in media with 3,5 or 10% (w/v) NaCl is similar. The photosynthetic apparatus is a lamellar type. The number of thylakoid stacks is a function of light intensity; at low light intensity there is generally only one large thylakoid stack, while at high light intensity 3–4 small, randomly distributed thylakoid stacks occur.

Ultrastructural evidence for the biflagellate origin of the uniflagellate fungal zoospore.

Abstract: The morphological similarities between the kinetosome and the second centriole of the zoospores of Phlyctochytrium kniepii and P. punctatum (Chytridiomycetes) suggest that the second centriole in the chytrid zoospore is a vestigial flagellum base. It is suggested that the term vestigial kinetosome may also be used when referring to the structure which is presently termed the second centriole of the chytrid zoospore. Morphological similarities between the chytrid zoospores of P. kniepii and P. punctatum and the zoospores of Rhizidiomyces apophysatus (Hyphochytridiomycetes) are noted. The possible biflagellate origin of fungi with uniflagellate zoospores is discussed. The third fiber (C fiber) of the kinetosome triplet is shown to form as an outgrowth of the B fiber of the kinetosome doublet.

Variation in the fermentative pattern of some Saccharomyces species.

Abstract: The acquisition of the ability to ferment galactose, maltose, sucrose, raffinose and melibiose by yeast strains of the genus Saccharomyces was investigated During cultivation in selective media 11 strains belonging to 5 species gained the ability to ferment one or several of these sugars De-adaptation was not usually observed after cultivation in glucose medium, indicating that the saltants are stable in this medium

Utilization of reducing power in growing cultures of Chromatium.

Abstract: The overall composition of cell material in the stationary growth phase of cultures of Chromatium strain 6412 cultivated with sulfide as electron donor is approximately (C5H8O2N). At the moment that sulfide became depleted, 42% had been oxidized to sulfur and 58% to sulfate. Thus at this time 69% of the reducing power initially present had been utilized. However, the amount of structural cell material produced was only 56% of the amount present in the stationary phase of growth. This discrepancy appeared to be due to the accumulation of storage carbohydrate. Storage carbohydrate was synthesized as long as sulfide was available and consumed after sulfide depletion. Increase in structural cell material after sulfide depletion could not be accounted for by CO2 fixation only, which indicates that storage carbohydrate can be converted into structural cell material. When stationary-phase cultures were again supplied with sulfide, growth was not observable in the first few hours, even though sulfide was oxidized, mainly to sulfur. Under these conditions reducing power was utilized for the synthesis of storage carbohydrate from CO2.

Chlorobium phaeobacteroides nov. spec. und C. phaeovibrioides nov. spec., zwei neue Arten der grünen Schwefelbakterien

Abstract: Two new species are described which comprise of the brown-colored rod-shaped and vibrio-shaped forms of the phototrophic green sulfur bacteria. In nature they occur at greater depths in lakes and ponds than the green-colored forms.

A serological investigation of hyphal growth in Fusarium culmorum

Abstract: Apical growth of hyphae of Fusarium culmorum was demonstrated using an immunofluorescent labelling technique. An antiserum prepared against hyphal tips contained a series of antibodies, detected by immunodiffusion, not present in antisera against mature hyphae or conidia. Absorption of the tip antiserum with hyphae allowed a specific immunofluorescence reaction with hyphal tips only. The antiserum against mature hyphae gave non-fluorescent tips to the hyphae.

Die Verwertung einfacher organischer Substrate durch Thiorhodaceae

Abstract: Es wurden 22 Gram-negative, Bacteriochlorophyll a enthaltende Stamme der Thiorhodaceae auf die Fahigkeit untersucht, verschiedene anorganische und organische Verbindungen als Wasserstoff-Donatoren und gegebenenfalls als Kohlenstoff-Quelle in Gegenwart von Bicarbonat und einer geringen Menge Sulfid als Reduktionsmittel und Schwefelquelle anaerob im Licht zu nutzen.