Quantitative field investigations of feeding and territorial behaviour of young-of-the-year brook charr,Salvelinus fontinalis

Synopsis Direct observations of young-of-the-year brook charr, Salvelinus fontinalis, in a second-order woodland stream indicated that most of their feeding effort was directed toward sub-surface, drifting prey (83% of feeding time). Feeding from the substrate and water surface was much less frequent (17% of feeding time). Comparisons of gut contents to drift net and substrate fauna samples corroborated that the most commonly consumed prey (chironomid and trichopteran larvae, ostracods, and ephemeropteran nymphs) were captured primarily from sub-surface, invertebrate drift. The disproportionate numbers of some prey species in the guts of several fish indicate that some prey selection occurred. Territories appeared to be cardioid-shaped, and were often contiguous, with dominance hierarchies evident among the residents. Agonistic interactions were frequent. Charges and chases predominated (91% of interactions) while lateral displays were infrequent (9% of interactions). Overall, these fish spent most of the daylight hours station-holding (77%) and feeding (18%). While only 3% of total time was spent in aggression, this amounted to 14% of the time a fish spent away from its station. There was some indication that territories were defended at a cost of feeding time.     

Histophotometric Evaluation of Glutamate Dehydrogenase Activity of the Rat Hippocampal Formation During Postnatal Development,with Special Reference to the Glutamate Transmitter Metabolism

Transmitter glutamate/aspartate synthesis is known to proceed along different metabolic pathways. In this light, the functional relevance of glutamate dehydrogenase in postnatally maturing glutamatergic/aspartatergic structures was studied by means of quantitative enzyme histochemistry. The basic requirements concerning the kinetics and calibration of the histochemical glutamate dehydrogenase reaction used were proved to be met in order to obtain valid quantitative data. The histochemically demonstrable activity of glutamate dehydrogenase (EC 1.4.1.3) in the hippocampal formation of the rat increased markedly during postnatal development. On day 30, the distribution pattern observed was similar to that in adult animals. While the enzyme activity rose within cell body layers from day 0 to day 30 by 240-285%, the increase in neuropil layers was found to be up to 830%. Maximum values were seen in the stratum lacunosum-moleculare of CA1 and CA3 and the stratum moleculare of the dentate fascia on day 30. Since the hippocampal neuropil is supposed to be copiously provided with glutamatergic (and aspartatergic?) structures which become functional in rats during the first weeks of postnatal life, the increase in enzyme activity is discussed to be primarily a consequence of maturing synaptic systems using glutamate and/or aspartate as transmitters.     

Nitrospira marina gen. nov. sp. nov.: a chemolithotrophic nitrite-oxidizing bacterium

A new chemolithotrophic nitrite-oxidizing bacterium, for which the name Nitrospira marina is proposed, was isolated from the Gulf of Maine. N. marina is a Gramnegative curved rod which may form spirals with 1 to 12 turns. Cells have a unique periplasmic space and lack intracytoplasmic membranes and carboxysomes. N. marina is an obligate chemolithotroph, but best growth is obtained in a mixotrophic medium. N. marina may be one of the most prevalent nitrite-oxidizing bacteria in some oceanic environments. Type strain is field with American Type Culture Collection (ATCC 43039).     

Distribution of polyamines in methanogenic bacteria

Members of all four families of methanogenic bacteria were analyzed for polyamine concentrations. High-performance liquid chromatography analysis of dansylated cell extracts revealed typical polyamine patterns for each family. Members of Methanobacteriaceae (family I) were characterized by very low polyamine concentrations; members of Methanococcaceae (family II) were characterized by putrescine and high spermidine concentrations; members of Methanomicrobiaceae (family III) were characterized by the presence of putrescine, spermidine, and sym-homospermidine; and members of Methanosarcinaceae (family IV) contained only high concentrations of sym-homospermidine in addition to putrescine. The highest polyamine concentration was found in Methanosarcina barkeri Jülich, with 0.35% putrescine in the dry cell material. The polyamine distribution found coincides with the dendrogram based on comparative cataloguing of 16S rRNA and offers a new, rapid chemotaxonomic method for characterizing methanogenic bacteria. Variation of the growth substrates (H2-CO2, methanol, acetate, and trimethylamine) for M. barkeri resulted in quantitative but not qualitative differences in polyamine composition.     

Mechanism of α Factor Biosynthesis in Saccharomyces cerevisiae

The biosynthesis of alpha factor, a mating-type-specific regulatory oligopeptide which is secreted by Saccharomyces cerevisiae cells of alpha mating type, was studied. In batch cultures only small amounts of the peptide were synthesized during the exponential growth phase. During the stationary phase, alpha factor was produced at a constant rate and accumulated in the culture medium. Inhibition of translation in wild-type cells by cycloheximide, or in mutant strains under conditions which blocked protein or ribonucleic acid (RNA) synthesis completely inhibited the production of alpha factor. These results indicate that the factor is produced by ribosomal translation of a specific messenger RNA and not by an extraribosomal mechanism of peptide synthesis.     

Die Brutzeiten einiger Gänsearten und ihrer Bastarde in identischen Bedingungen

Zusammenfassung An Hand von 229 Brutbeginn-Daten von freilebenden Gänsen, die während der Jahre 1956–1966 in Seewiesen (Obb.) (48°N, 11°11E) brüteten, wurden die mittleren Brutbeginn-Daten von 5 Gänsearten und von Artbastarden bestimmt. Es zeigte sich, daß die untersuchten Arten unter diesen Bedingungen in derselben Reihenfolge brüteten, wie ihre Artgenossen in freier Wildbahn. Die mittleren Brutbeginn-Termine wurden allerdings um so mehr vorverlegt, je später die Art normalerweise brütet (Abb. 1). , die mit artfremden verpaart waren, brüteten zur selben Zeit wie ihre Artgenossen, die mit artgleichen verpaart waren (Abb. 1). GraugansxSchneegans-Bastard-, die mit Schneegantern verpaart waren, begannen meist nach den Graugänsen, aber stets vor den Schneegänsen zu brüten (Abb. 1, 2). Das intermediäre Brüten dieser wird als starkes Argument für die Richtigkeit der Hypothese gewertet, nach welcher die artspezifisch verschiedenen Brutzeiten wenigstens zum Teil genetisch bedingt sind. In der Diskussion wird die Frage kritisch erörtert, wie weit schon allein die Tatsache, daß die verschiedenen Arten über Generationen hinweg in derselben Reihenfolge wie ihre wildlebenden Artgenossen zu brüten beginnen, als Beweis für derartige genetische Unterschiede angesehen werden kann.

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Summary In 229 cases onset of breeding was recorded from free-living geese of 5 species and of some hybrids of these species, kept in Seewiesen/Obb. (48° N, 11° 11E) from 1956 to 1966. It was found that the species under these conditions bred in the same seasonal sequence as did wild birds. The mean breeding times, however, were found to be advanced in relation to the onset of breeding in the wild (Fig. 1). This was especially evident in the case of late-breeding species. paired with of another species came into breeding condition at the same time as paired with of the same species (Fig. 1). GraylegxSnowgoose hybrid paired with Snowgoose in most cases started to breed later than Greyleg geese but always earlier than the mean breeding time for Snowgeese (Fig. 1, 2). This intermediate breeding time is taken as a strong argument for the hypothesis that the species specific differences in breeding times are, at least in part, genetic in origin. The question as to the extent to which the differences in breeding times alone, persisting for generations in the same sequence as those of wild birds, can be attributed to genetic differences between the species, is critically discussed.

     

Acetylcholinesterase in der Pars distalis von Zonotrichia leucophrys gambelii (Aves)

Zusammenfassung In beiden Lobi der Pars distalis photosensitiver Zonotrichia leucophrys gambelii-Männchen bewirkt die photoperiodische Stimulation unter Langtagbedingungen das Auftreten von Acetylcholinesterase, die, solange die Vögel unter Kurztagbedingungen gehalten wurden, nicht oder nur in geringer Menge vorhanden war. Das Enzym ist auf PAS-positive Zellen beschränkt, doch nicht in allen von ihnen anzutreffen. Nach dem Erreichen eines Maximums zwischen Tag 31 und Tag 52 sinkt der AChE-Gehalt wieder und nähert sich nach 80 Tagen dem Ausgangsstadium. Der Parallelismus zwischen den Testesgewichten und der AChE-Aktivität läßt vermuten, daß die AChE-Zellen gonadotropes Hormon bilden.

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Acetylcholinesterase in the Pars distalis of Zonotrichia leucophrys gambelii (Aves)

Summary Photoperiodic stimulation of photosensitive male white-crowned sparrows, Zonotrichia leucophrys gambelii, causes the appearance of acetylcholinesterase activity in the cephalic and caudal lobes of the pars distalis. In photosensitive birds held on short daily photoperiods little or no activity can he demonstrated histochemically. The enzyme is restricted to PAS-positive cells. After attaining a maximum between 31 and 52 days after the beginning of photoperiodic stimulation (20 hours of light per day), AChE activity declines and after 80 days returns approximately to the initial level of short-day birds (eight hours of light per day). The correlation between the increase in weight of the testes and AChE activity, and other considerations, suggest that these AChE cells must produce gonadotropic hormones. Our observations are generally consistent with the results of the biochemical studies of Russell (1968) on the AChE activity in the pars distalis of the same species.

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Mit Unterstützung durch National Institutes of Health (Grant 5R01 NB 06187, Prof. Farner, Principal Investigator).

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Institut für Haustierkunde der Universität Kiel (Direktor: Prof. Dr. Dr. h. c. Wolf herre).     

Zur Substantivität von Tetrazoliumsalzen in der Histochemie

Zusammenfassung Die in der Literatur beschriebenen Beziehungen zwischen Substantivität und chemischem Bau der in der Histochemie verwendeten Tetrazoliumsalze wurden an weiteren Tetrazoliumsalzen überprüft. Die Untersuchungen ergaben, daß die Anzahl und die Stellung der Nitrogruppen im Molekül an Bedeutung für die Substantivität des Tetrazoliumsalzes hinter dem Einfluß einer linearen, aromatischen Substitution am N(₃) des Tetrazolringes bzw. einer Molekülverdoppelung zurücktreten. Es ist zwischen einer Substantivität der Tetrazoliumsalze und einer Substantivität der Formazane zu unterscheiden.

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On substantivity of tetrazolium salts in histochemistry

Summary The known correlations between substantivity and chemical constitution of tetrazolium salts used in histochemistry are further examined on several tetrazolium salts. The investigations are demonstrating that number and position of the nitro groups in the molecule are less important for substantivity of the salt than the influence of a linear, aromatic substitution on N(₃) of the tetrazol ring or of doubling the molecule. It is to differentiate between substantivity of tetrazolium salts and the substantivity of the formazans.