Phosphate repression of cephamycin and clavulanic acid production by Streptomyces clavuligerus

Summary Production of cephamycin and clavulanic acid by Streptomyces clavuligerus is controlled by the phosphate concentration. Phosphate represses the biosynthesis of cephamycin synthetase, expandase and clavulanic acid synthetase. In the presence of 2 mM phosphate, the specific activities of expandase, cephamycin synthetase and clavulanic acid synthetase were higher than in the presence of 75 mM phosphate. The specific activity of cephamycin synthetase is maximal with an initial phosphate concentration of 10 mM, whereas the specific activity of expandase is maximal with 1 mM phosphate. A correlation between cephamycin synthetase specific activity and expandase specific activity was established at phosphate concentrations higher than 10 mM. This shows that the expandase is an important enzyme in the mechanism by which the phosphate concentration affects the biosynthesis of cephamycin.     

Die Feinstruktur der Zirbeldrüse normaler,trächtiger und experimentell beeinflußter Meerschweinchen

Zusammenfassung In der Meerschweinchenzirbeldrüse lassen sich elektronenmikroskopisch helle und dunkle Pinealzellen sowie einzelne Gliazellen nachweisen. In den bei weitem überwiegenden hellen Pinealzellen zeichnet sich ein Teil der vesicle-crowned rodlets (VCR) durch lokale Auftreibungen aus. Von VCR deutlich abzugrenzen sind die vesicle-crowned balls (VCB). Erstmalig beschrieben wird das Vorkommen von sog. Zylindern, die als Vorstufen von VCB aufgefaßt werden. In den relativ seltenen dunklen Pinealzellen, die sich durch chromatinreiche Kerne und elektronendichtes Zytoplasma auszeichnen, sind Vesikel, VCR, VCB und Zylinder seltener als in hellen Pinealzellen. Die reichlich vorhandenen marklosen Nervenfasern finden sich vor allem in perivasculären Räumen, seltener im Parenchym. Synapsen zwischen Nerven und Pinealzellen wurden nicht beobachtet. In den Zirbeldrüsen trächtiger Meerschweinchen zeichnen sich in der 2. Hälfte der Tragzeit die hellen Pinealzellen durch stärkere Lappung der Kerne, gehäuftes Auftreten von laktiven Zonen, Vermehrung von Mitochondrien, glattem ER, agranulären Vesikeln, VCR, VCB und Zylindern aus. Die dunklen Pinealzellen nehmen während der Tragzeit an Zahl zu. Post partum bilden sich diese Veränderungen innerhalb einer Woche zurück. Längerer Aufenthalt der Tiere in Dunkelheit führt zu einer Aktivierung der hellen Pinealzellen mit auffallender Vermehrung der VCR und zu einer Zunahme der dunklen Zellen. Unter Dauerbelichtung kommt es in den hellen Zellen zu einer Abnahme fast aller Zellorganellen und zu einer starken Vermehrung der VCR, die nach 70 Tagen auch Formveränderungen aufweisen. Nach Reserpinbehandlung beobachtet man eine Verminderung und degenerative Veränderungen der VCR. Es wird diskutiert, daß die VCR als prae- bzw. postsynaptische Strukturen der Erregungsübertragung von Nerven zu Pinealzellen bzw. von Pinealzellen untereinander dienen könnten.

---

The fine structure of the pineal gland of normal, pregnant and experimentally affected guinea-pigs

Summary By means of electron microscopy light and dark pinealocytes can be distinguished in the guinea-pig pineal gland. Glial cells are rare. In the light pinealocyte. the most frequent cell type, some vesicle-crowned rodlets (VCR) show circumscribed thickenings. From these structures vesicle-crowned balls (VCB) have to be clearly distinguished. Furthermore cylinders occur, which, it is suggested, are precursors of VCB. Dark pinealocytes characterized by chromatin-rich nuclei and electron-dense cytoplasm are rare and contain fewer vesicles, VCR, VCB and cylinders than light pinealocytes. Numerous non-myelinated nerve fibres are situated within perivascular spaces, a few also in the parenchyma. Synapses between nerve fibres and pinealocytes were not observed. In the pineal gland of pregnant guinea-pigs the following changes can be observed in the second half of gestation. The light cells show many nuclear indentations and an increase of active zones, mitochondria, smooth ER, agranular vesicles, VCR, VCB, and cylinders respectively. The dark cells increase in number. After birth these changes reverse to normal within one week. Constant darkness leads to an activation of the light cells accompanied by an increase of the VCR and to an increase in number of the dark cells. Under constant illumination the light cells show a decrease of their organelles and a strong increase of the VCR. After 70 days the VCR also show a change in shape. Following reserpine treatment the VCR decrease in number and show signs of degeneration. It is discussed that the VCR function as pre- or postsynaptic structures and that they are involved either in transmitting impulses from nerve fibres to pinealocytes or from one pinealocyte to the other.

Untersuchung unter Leitung von Univ.-Doz. Dr. L. Vollrath.     

Concluding remarks

On the basis of symposium contributions onChlorella, Hibbertia, Eucalyptus, Ambrosia and on numerical approaches some fundamental problems of (bio)systematics, evolution, and taxonomic categories are discussed: Methods available for analysing affinities; conflicting evidence from phenetic, biochemical, cytogenetic and other analyses; further classification problems in cases of intermediacy, etc. While sibs of various levels and their natural hierarchy often can be objectively defined, this appears impossible for particular taxonomic levels itself (e. g. species). A single objective taxonomic system of organisms is unrealistic. Certain guiding lines for relative and practicable concepts of species and genus are proposed.Presented at the symposium Speciation and the Species Concept during the XIIth International Botanical Congress, Leningrad, July 8, 1975.     

Silver staining the chromosome scaffold

Cytological silver-staining procedures reveal the presence of a core running along the chromatid axes of isolated HeLa mitotic chromosomes. In this communication we examine the relationship between this core and the nonhistone chromosome scaffolding, isolated and characterized in previous publications from this laboratory. When chromosomes on coverslips were subjected to the steps used for scaffold isolation in vitro and subsequently stained with silver, the characteristic core staining was unaffected. Control experiments suggested that the core does not contain large amounts of DNA. When scaffolds were isolated in vitro, centrifuged onto electron microscope grids, and stained with silver, they were found to stain selectively under conditions where specific core staining was observed in intact chromosomes. These results suggest that the nonhistone scaffolding is the principal target of the silver stain in chromosomes.     

Wellenmessungen im Seegebiet der Piep (Deutsche Bucht)

Zusammenfassung 1. In Form von Seegangscharakteristiken werden Meßergebnisse über mittlere und maximale Wellenhöhen sowie mittlere Perioden des Seegangs an vier Beobachtungs-stationen im Seegebiet der Piep (Deutsche Bucht) mitgeteilt.2. Die Ergebnisse zeigen, daß die Abhängigkeit der maximalen Wellenhöhen von der Windrichtung sehr ausgeprägt die Topographie des Beobachtungsortes widerspiegelt. Für die mittleren Wellenhöhen ist das nicht in gleichem Ausmaße der Fall, es gilt nur für einigermaßen frei zur See liegende Stationen.3. Als maximale Wellenhöhe bei WSW-Wind von Beaufort 10 an der Station Trischen ergab sich 3,2 m, bei Tertius, Scholloch und Tonne 16 2,8; 2,5 bzw. 2,4 m.

---

Wave measurements in the sea area of the Piep (German Bight)

In form of wave characteristics, results of measurements of mean and maximum wave heights as well as mean periods of the sea at four observation stations in the sea area of the Piep (German Bight) are presented. The results show a very strong dependence of the maximum wave heights upon the topography of the observatory position. In case of mean wave heights this dependence is not so strong for stations with near coast positions. At Beaufort 10, as maximum wave height at station Trischen 3.2 m resulted; at Tertius, Scholloch and Tonne 16 maxima were 2.8, 2.5 and 2.4 m, respectively.

     

Lipid profile of rat myelin subfractions

Myelin from adult rat brains was separated on a discontinuous sucrose gradient into three subfractions. Analysis of light, heavy and membrane fraction lipid classes was performed by HPTLC and densitometry while fatty acid composition was determinated by GLC. The more interesting results observed are: i) the membrane fraction resembles in its lipid and fatty acid composition other cell membranes (particulary oligodentrocytes); ii) light and heavy myelin are quite similar between them but the former has a higher content of sphingomyelin, a lower hydroxy/nohhydroxy cerebrosides ratio and a lower content of monoenoic fatty acids than the heavy subfraction. The results obtained could explain the different structures observed in each myelin subfraction since fatty acid composition, hydroxy fatty acids, sphingomyelin and cholesterol play a key role in the stability and structure of membranes.     

Methodological problems in evolutionary biology III. Selection and levels of organization

Apparently factual disagreement on the level(s) at which selection operates often results from different interpretations of the term selection. Attempts to resolve terminological problems must come to grips with a dilemma: a narrow interpretation of selection may lead to a restricted view on evolution; a broader, less precise, definition may wrongly suggest that selection is the centre of a unified, integrated theory of evolution. Different concepts of selection, therefore, should carefully be kept apart.     

A quick procedure for anaerobic fermentation tests in the identification of yeasts

Summary The melting-point tube method of Clarke and Cowan (1952) is used for testing anaerobic fermentations with yeast cells produced in aerobic growth tests. The same sugar is used for testing both growth and fermentation. With this procedure, most anaerobic fermentations were detected in <3 h, and even those hitherto described as weak or slow and involving inducible catabolic systems in <18 h.     

Water accessibility to plant roots in different soil structures occurring in the same soil type

The capacity of a soil to supply roots with water and nutrients for crop growth is important when defining sustainable land management which implies maintenance of production and reduction of production risks. Not only the amount of available water is important but also its accessibility, which differs among different soil structures. Different structures within one soil series were associated with three types of management: (i) conventional, temporary grassland (Conv), (ii) biodynamic, temporary grassland (Bio) and (iii) conventional permanent grassland (Perm). Transpiration of barley plants, under identical circumstances, and the associated rooting patterns, were measured in five large undisturbed cores from each of the three soil structures. Management had significantly changed bulk density, organic matter content and porosity. Measured transpiration showed significant differences with highest amounts for Perm followed by Conv and lowest amounts for Bio. Rooting pattern characteristics, defined as the relation between a series of hypothetical extraction zones around each root and the volumes of excluded soil were determined for the three structures. These rooting pattern characteristics were most favourable for Perm, followed by Bio and Conv, respectively. The water supply characteristics, defined as the number of days the soil can satisfy a transpiration demand of 5 mm d^-1 as a function of a hypothetical extraction zone, reflects the capacity of the soil to supply roots with water. These water supply characteristics combined with the rooting pattern characteristics were used to quantify the accessibility of soil water. Accessibility was highest for Perm and Conv with 95% and 94% respectively, followed by Bio with 68%. When used in a simulation model and compared with simulations implicitly assuming total accessibility, measured transpirations were better simulated by introducing the expression for water accessibility.     

Transmembrane electron transport and the neutral theory of evolution

Based on the concept of pairs of basic functional states the evolution of the first chemiosmotic mechanism of energy conversion is discussed in terms of point mutations, gene duplications and of the neutral theory of evolution. A model for estimating the overall probability of the evolutionary step in question is presented, both for the selectionist and neutralist position. It is concluded that, concerning the present stage of knowledge, the evolution of transmembrane electron transport is an unsolved problem in evolutionary biology.     

NADH dehydrogenase: a new molecular marker for homoeology group 4 in Triticeae. A map of the 4RS chromosome arm in rye

Summary Structural gene loci encoding the monomeric isozymes nicotin adenin dinucleotide dehydrogenase (NADH dehydrogenase or NDH) have been located on the 4AL, 4B, and 4DS chromosome arms of Triticum aestivum cv Chinese Spring, on the 4RS chromosome arm of Secale cereale cultivars Imperial, King II, Dakold, and Ailes, on the 4S¹ S/7S¹ chromosome of Aegilops longissima, the 4E of Elytrigia elongata, and the CSU-A of Aegilops umbellulata. All the results support the homoeologous relationships among these chromosomes in the five species studied. In addition, a map of the 4RS chromosome arm in cv Ailes has been realized, linking loci Pgm-1 (located on the 4RS chromosome arm) and Ndh-1 (17.91 cM), with an estimated distance between both loci and the centromere of 20.00 cM and 32.12 cM, respectively.     

The adaptive significance of cultural behavior: Comments and reply

Summary Fundamentally, theoretically, there is only one process underlying genetic and cultural evolution: natural selection. Organism fitness-enhancement (adaptive significance) is one of its practical mechanisms; group formation and maintenance is another, often but not always through fitness-enhancement; and need-fulfillment is still another. If Durham can accept that formulation, and switch from organism-thinking to instruction-thinking (Cloak, 1975: 178), he will free himself from two handicaps: First, he can forget his worries about reductionism and determinism (1976a: 100, 101). Under this general theory of natural selection, cultural evolutionis biological evolution, continued by other (nongenetic) means. Second, he will spare himself the appearance of anthropomorphism, mentalism, and wishy-washiness attendant on his discussion of kinds of significance, other than adaptive significance, of cultural behaviors (1976a: 102–106, 115).     

The rapid switch-off of nitrogenase activity in obligate methane-oxidizing bacteria

Nitrogenase activity in the obligate methaneoxidizing bacterium Methylococcus capsulatus (Bath) was added ammonia. This observation was extended to include other ammonia. This observation was extended to include other representative N₂-fixing species of methanotrophs. The ammonia switch-off of nitrogenase in M. capsulatus (Bath) was reversed on washing cells to remove excess ammonia, in the presence of chloramphenicol, suggesting that a form of covalent modification of nitrogenase may occur. Replacing the oxidizable substrate methanol with formaldehyde, formate, ethanol or hydrogen had no effect on nitrogenase switch-off. A number of potential nitrogen sources or intermediates of nitrogen metabolism such as glutamine, asparagine, glutamate and alanine when tested, did not effect switch-off. However, the rapid inhibition of nitrogenase activity of M. capsulatus (Bath) could be achieved by adding the uncoupler carbonylcyanide m-chlorophenylhydrazone or nitrite. The glutamine synthetase inhibitor methionine sulphoximine blocked the switch-off effect of ammonia, indicating that the metabolism of ammonia may be essential for switch-off to occur. Inhibitors of glutamate synthase did not alleviate the ammonia switch-off response. Methionine sulphoximine did not alleviate the rapid inhibition of nitrogenase by carbonylcyanide m-chlorophenylhydrazone indicating that the shortterm regulation of nitrogenase by uncouplers and ammonia proceed via different mechanisms.Abbreviations MSX methionine-DL-sulphoximine - DON 6-diazo-5-oxo-L-norleucine - GS glutamine synthetase - GOGAT glutamine 2-oxoglutarate aminotransferase (glutamate synthase) - CCCP carbonylcyanide m-chlorophenyl hydrazone     

Ultrastructure of four types of striated muscle fibers in the atlantic hagfish (Myxine glutinosa,L.)

Summary Four types of striated muscle fibers with distinctive ultrastructure were defined in the Atlantic hagfish (Myxine glutinosa, L.): white, intermediate, and red fibers of m. parietalis, and red fibers of m. craniovelaris.White fibers are thick, contain very few mitochondria and fat vacuoles, and possess distinct and separate myofibrils with thin Z-disks and distinct M-lines. Intermediate fibers are thinner, possess largely similar myofibrils that often are even better separated due to a higher content of fat vacuoles and especially mitochondria and glycogen granules. Red fibers of m. parietalis contain large amounts of mitochondria, fat vacuoles, and glycogen granules. Their myofibrils possess M-lines, and although branching more, the myofibrils of red fibers conform with a Fibrillenstruktur pattern like those of white and intermediate fibers. Red fibers of m. craniovelaris are very thin, possess many smaller fat vacuoles, and large amounts of mitochondria and glycogen granules. The myofibrils are significantly thinner than in m. parietalis fibers, run as quite independent well separated units, possess thicker Z-disks, and lack M-lines. Large amounts of myosatellite cells are associated with these red fibers.Triads are located near A/I-junctions in all four fiber types and occur irregularly, the density of triads being different in the various fiber types.We are indebted to Dr. Finn Walvig, Biological Station, University of Oslo, Drøbak, for supply of hagfishes, and we also wish to thank Dr. Jan K. S. Jansen, Institute of Physiology, University of Oslo, for valuable suggestions during this study.     

Heterochromatin variation in Cryptobothrus chrysophorus

Northern and southern races of the Australian grasshopper Cryptobothrus chrysophorus share the same diploid chromosome number (2n=23, 24). The northern race is differentiated from the southern by fixed extra blocks of heterochromatin located distally on five of the six medium pairs of autosomes (M4, 5, 6, 8 and 9). The megameric M7 pair, which is completely heterochromatic in both races, is also frequently larger in the northern race. Additionally, while there is considerable polymorphism for the presence of supernumerary heterochromatic segments on the two smallest autosome pairs (S10, 11) in both races, the precise character of this polymorphism is strikingly different between them. That found in the north is both more extensive and more variable. An analysis of the patterns of C-banding obtained in neuroblast c-mitoses indicates even more variation within and between races than was anticipated from the patterns of heteropycnosis seen at first prophase of male meiosis. Thus, while the distal blocks on the M4, 6, 8 and 9 elements in the northern race invariably C-band those of the M5 never do. On the other hand polymorphisms for C-bands on the M5, 6, 8 and 9 are seen in some populations of the southern race but in regions which are not visibly heteropycnotic at meiosis. Polymorphisms for the pattern of C-banding also occur in the northern race populations in the M4, 6, 8 and 9 elements and some of these are associated with clear length differences in the chromosomes concerned. Others involve differences in the expression of the distal C-bands in M8 and 9 which vary from dark to intermediate. The supernumerary segments on the S10 and 11 pairs are especially variable in respect of their C-banding properties. Some are entirely C-banded, some show no C-banding whatsoever and some are composed of both banded and unhanded regions. Banding is again most pronounced, however, in the northern race. Finally the character of the megameric M7 is strikingly different in the two races not only in respect of its size, which is sometimes larger than that of the south, but also in respect of the extent of C-banding which is always more complex in the northern form irrespective of its size.     

Mitochondrial genetic damage induced in yeast by a photoactivated furocoumarin in combination with ethidium bromide or ultraviolet light

Summary Ethidium bromide (EB) and ultraviolet light (UV) in combination are known to produce a synergistic induction of petite mutants in yeast. Two other agents were combined with EB, 3-Carbethoxypsoralene (3 CPs) activated by 365 nm light or rays. EB in combination with 3 CPs also resulted in an enhanced production of petite mutants. After the photoaddition of 3 CPs in exponential phase cells, recovery of the petite mutation during dark liquid holding was inhibited by the presence of EB producing an enhanced number of petite mutants. The behavior of mitochondrial antibiotic resistance markers after individual and combined treatments with EB and 3 CPs indicates a random loss of markers after EB and a preferential loss of a certain region for the 3 CPs photoaddition. The combination of the two agents leads to an additivity of total drug marker losses rather than a synergistic loss. The combination of EB with rays produced no enhancement in petite induction. A combination of UV and 3 CPs showed a synergistic interaction for petite induction. These results indicate that the three agents, EB, UV and 3 CPs photoaddition may share a common repair step for mitochondrial lesions.     

Über das Verhalten von Champignonstämmen in Mischkultur

Zusammenfassung Mischungen aus dem Mycel sweier weißer oder zweier brauner Stämme des Kulturchampignons hatten keinen Einfluß auf den Fruchtkörperetrag.Bei Mischungen aus einem weißen und einem braunen Stamm was dagegen der Ertrag immer niedriger als erwartet und das Mycel verschwand verhältnismäßig schnell. Der Ertragsausfall beruht in der Regel auf einer Unterdrückung des braunen Stammes.Herrn Prof. von Sengbusch zum 65. Geburtstag in Dankbarkeit und Verehrung gewidment.     

A framework for classifying subsistence production types of Nepal

This paper defines a four-tiered, hierarchical system for classifying subsistence production types in Nepal and uses the system to describe the subsistence communities of central Nepal. The system first divides Nepal into a grid of homogenous parts or cells, second, it divides, the cells into ridge-valley slope sequences, third, defines production types for the ridge-valley slope sequences, and, finally, distinguishes local variants of the production types. After describing these tiers, I apply these categories to the northern portions of the central and western development regions where I have done research. I then define how representatives of Nepal as a whole are the production types defined for the central and western development regions. Finally, the paper locates some completed studies within its framework.     

Preparation and characterization of methyl green tetrafluoroborate

Summary Commercial methyl green dyes were converted to tetrafluoroborate by means of NaBF₄-solution, the compounds thus obtained were analytically pure. It was shown to be possible to distinguish between a methyl and an ethyl compound by means of NMR spectroscopy. The dyes are stable in buffered aqueous solution, and in crystalline form. A spectrophotometric assay is proposed.     

Plant regeneration from cytoplasmic hybrids of rice (Oryza sativa L.)

Summary We obtained cybrid plants by electrofusing -irradiated protoplasts of a cytoplasmic male-sterile line A-58 CMS (Oryza sativa L.) and iodoacetamide (IOA)-treated protoplasts of the fertile (normal) rice cultivar Fujiminori. The cybridity of the plants was confirmed by mitochondrial (mt) DNA restriction endonuclease, and plasmid-like DNA analyses, and by isozyme, cytological and morphological investigations. The chromosome number of the cybrid plants is 24.