On maturation of the bacteriophage lambda chromosome

Summary Repressed lambda chromosomes that possess a duplication of the cohesive end site (cos site) are matured during lytic growth of 80. This result is in contrast to repressed non-duplication lambda chromosomes that are not matured by 80. DNA molecules matured by 80 are unreplicated and lack the duplication: both cos sites are cleaved. These results indicate that in normal lambda development, mature, unit-length chromosomes are generated from a multichromosomal length of lambda DNA by cleavage of two cos sites.     

Sequential control of phytochrome-mediated synthesis de novo of β-amylase in the cotyledons of mustard (Sinapis alba L.) seedlings

In the cotyledons of mustard (Sinapis alba L.) seedlings irradiated from the time of sowing with continuous red light, the photoreversibility of the phytochrome-mediated increase in -amylase activity (EC 3.2.1.2) is lost 36 h after sowing (coupling point). However, the induced increase of -amylase activity cannot be detected before 46 h after sowing (starting point). Density labeling with deuterium oxide shows that the increase of enzyme activity in light and darkness coincides precisely with the synthesis of -amylase protein. Thus, phytochrome mediates an increase of -amylase synthesis de novo. Since there is no turnover detectable by density labeling, it is concluded that -amylase of mustard cotyledons is a physiologically stable enzyme (half-life >5 d). The 10-h time gap between loss of photoreversibility and onset of light-induced -amylase synthesis points to a relatively stable regulatory element within the signal chain (transmitter) which links -amylase synthesis to the primary action of phytochrome. A 12-h lag between the cessation of phytochrome action and the cessation of induced -amylase synthesis indicates a limited lifetime of the transmitter (about 12 h). The effect of this result on the interpretation of the coupling point is discussed.Abbreviations P_r, P_fr red and far-red absorbing forms of phytochrome     

On the ultrastructure of the abdominal sense organ of the giant scallop,Placopecten magellanicus (Gmelin)

Summary The abdominal sense organ of the giant scallop, Placopecten magellanicus, is composed of two cell types. The presumed receptor cells bear a single cilium 60 to 70 m in length. The microvilli at the apices of these cells may also be modified into microvillous whorls. From eight to twelve ciliated cells are associated with a single mucous cell. The mucous cells have a much greater diameter than the ciliated cells and contain many electron-dense mucous granules. No function has yet been determined for the ciliated cells, although a number of theories are presented.This research was supported by National Research Council of Canada Operating Grant No. A-6444 to Dr. V.C. Barber. Additional support came from the Department of Biology and the School of Graduate Studies, Memorial University. Contribution no. 250 from the Marine Sciences Research Laboratory, Memorial University of Newfoundland     

Cytoarchitectonic pattern of the hypothalamus in the cobra,Naja naja

Summary The distribution and cytoarchitectonic pattern of the magno- and parvocellular hypothalamic nuclei of the cobra, Naja naja, are described at the light-microscopic level. With respect to their tinctorial affinity to paraldehyde fuchsin (AF) as a representative of the Gomori-type of stains, the magnocellular neurons belong to the AF-positive and the parvocellular neurons to the AF-negative elements. In addition to the supraoptic and paraventricular nuclei proper, two accessory aggregations of magnocellular neurons, the nucleus retrochiasmaticus and nucleus circularis, can be identified. Although in a peculiar location, they may be regarded as subunits of the supraopticoparaventricular neurosecretory complex. As many as 22 AF-negative nuclear areas are identified in the hypothalamus of the cobra. The nucleus periventricularis hypothalami of earlier authors is subdivided into several circumscribed neuronal complexes. The nucleus arcuatus, nucleus hypothalamicus lateralis and nucleus lateralis recessus infundibuli are well developed. An attempt is made to interpret the significance of these nuclei on a comparative and phylogenetic basis.On leave from the Department of Zoology, Nagpur University, Nagpur, India     

Neuroanatomical,immunocytochemical, and physiological studies of the pharyngeal retractor muscle and its putative regulatory neurons playing a role in withdrawal and feeding in the snail, <Emphasis Type="Italic">Helix pomatia</Emphasis>

We describe the neurons regulating two separate functions of the pharyngeal retractor muscle (PRM), namely sustained contraction during body withdrawal and rhythmic phasic contractions during feeding, in the snail, Helix pomatia. The distribution of central neurons innervating the PRM is organized into two main units; one in the buccal-cerebral ganglion complex, the other in the subesophageal ganglion complex. Serotonin- (5-HT-), FMRFamide- (FMRFa-), and tyrosine-hydroxylase-immunostained neurons are present among the PRM neurons that densely innervate the PRM. 5HT both decreases and increases the amplitude of the electrically evoked contraction between concentrations of 0.1 M and 1 M. Dopamine (DA) only decreases the amplitude of contraction at a 1-M threshold concentration. In contrast, FMRFa increases the amplitude of the contraction and slightly elevates the tone of the PRM but requires a higher threshold (10 M). Assay by high-performance liquid chromatography of 5HT and DA in the PRM has shown that the 5HT level decreases during locomotion but increases during feeding, whereas the DA level increases during locomotion but slightly decreases during feeding. Thus, different segments of the PRM are innervated by neurons from different loci within the central nervous system. The segments of the PRM distal to the pharynx are innervated from loci of the subesophageal ganglion complex suggesting that they mediate withdrawal. The proximal segment of the PRM is innervated from cerebral and buccal loci indicating that these neurons mediate the feeding rhythm produced by buccal and cerebral feeding central pattern generators to induce rhythmic phasic contractions in the PRM during feeding.This work was supported by Hungarian Scientific Research Fund (OTKA) grants (T034106, T037389, T037505), the Wellcome Trust CRIG Programme, and the Wellcome Trust Travel Grant.     

In vitro organogenesis of elephant apple (Feronia limonia)

Elephant apple (Feronia limonia L.). was micropropagated on MS medium containing 4.4 M benzyladenine and 4.6 M kinetin using cotyledon explants taken from in vitro-grown seedlings. Adventitious buds formed on the cotyledon developed into shoots that were rooted in half-strength MS medium containing 0.57 M indoleacetic acid and 0.49 M indolebutyric acid. Plants were successfully established in soil.Abbreviations BA 6-benzyladenine - IAA 3-indoleacetic acid - IBA 3-indolebutyric acid - MS Murashige & Skoog     

Ultrastructural investigation of spicule formation in the gorgonianLeptogorgia virgulata (Lamarck) (Coelenterata: Gorgonacea)

Summary Ultrastructural examination of original and regenerated branch tips of the gorgonianLeptogorgia virgulata reveals that spicule formation begins with the aggregation of scleroblasts in the mesoglea. Calcite crystal deposition occurs within a Golgi vacuole containing organic matrix. Vacuole size increases while matrix incorporation and subsequent crystal growth continue, filling the vacuole. At approximately this time, the scleroblasts dissociate and wart formation begins. Further spicule growth stretches the cell into a thin envelope. Fusion of vacuole and plasma membrane followed by breach formation during spicule growth, as well as scleroblast atrophy or migration from mature spicules, result in the transition of the spicule from the intracellular to the extracellular environment. The results also reveal aborted spicules and digestive bodies, implying possible relationships among calcification, detoxification, and waste management.Contribution No 436, Belle W. Baruch Institute for Marine Biology and Coastal Research, University of South Carolina, Columbia, South Carolina, 29208, USA     

In vivo estrogen uptake by individual cell types of the rat anterior pituitary after short-term castration-adrenalectomy

Summary In vivo estrogen uptake was measured in five anterior pituitary cell types of the rat by a quantitative autoradiographic-immunocytochemical technique. In male and female rats that had been castrated and adrenalectomized for one day all five cell types showed nuclear concentration of label one hour after injection of ³H-estradiol. The order of labeling intensity was lactotropes > somatotropes > gonadotropes > corticotropes > thyrotropes. No significant overall sex difference in estrogen uptake was apparent although male pituitaries tended to take up slightly more. Physiological correlates to these data are discussed.Supported by PHS grant HD 12173 and Research Career Development Award HD 00243I wish to acknowledge Mr. Sing Kung Lau for his excellent technical assistance and Dr. P. Rodier for her advise and assistance with the statistical analysis. I also wish to thank Dr. A.F. Parlow and NIAMDD for antisera against rLH, hFSH, rPRL and rTSH and Dr. P. Petrusz, University of North Carolina, for antisera against bGH and h endorphin     

Reaction chain in feeding behavior ofHydra: Different specificities of three feeding responses

Summary Hydra shows three types of feeding responses to chemostimulants. They are writhing of tentacles, ball-formation of tentacles and mouth-opening.The chemostimulants can be divided into 3 classes on the basis of specificities of the responses they elicit. The first class includes tripeptides glutathione (reduced form) and S-methyl-glutathione. These chemicals evoke all three types of responses. The second class contains dipeptides-glutamylcysteine,-glutamyl-S-methyl-cysteine and-glutamyl--amino butyrate and amino acidl-arginine. These chemicals evoke mouth-opening and writhing of tentacles, but not ball-formation. The third group contains amino acidsl-leucine,l-tryptophan andl-lysine. These chemicals evoke writhing and ball-formation of tentacles but not moutho-pening. These observations indicate the existence of different specificities of the three feeding responses inHydra to chemostimulants.In addition to evoking tentacular movements, the amino acids of the third group also have the capacity to competitively inhibit the mouthopening response induced by S-methyl-glutathione. Evidence exists which suggests thatHydra has different receptors for those amino acids which inhibit mouth-opening and for those which evoke the tentacular movements.Tentacles cut off animals show the typical writhing response to S-methyl-glutathione. The sensitivity of this response is similar to the response of tentacles on intact animals. This suggests that the entire set of receptor-effector system for writhing response is present in individual tentacles. The present results suggest that each feeding response is executed by a different receptor-effector system.Abbreviations GSH reduced glutathione - GSM S-methyl-glutathione - -Glu-CysH -glutamyl-cysteine - -Glu-CysMe -glutamyl-S-methyl-cysteine - -Glu-Abu -glutamyl--aminobutyr-ate     

Shallow water meiobenthos of the bermuda platform

Summary The distribution and abundance of subtidal meiobenthos were studied monthly from June 1967 through May 1968 at five stations on the Bermuda platform: Two in Castle Harbor, two in Baileys Bay, and one in Harrington Sound. Total number of individuals ranged from 12.2–133.3x10⁴/m² and dry weight biomass from 33–259.3 mg/m². Free-living nematodes constituted 72.6% of the total numbers and 71.8% of the biomass and were the most abundant organisms at all but one station. Harpacticoid copepods were second in overall abundance and were the most abundant organism at one station. Polychaetes, ostracods, a kinorhynch and a priapulid were also common.Distinct seasonal patterns were observed. Total population values were highest in late spring, lowest in the winter. Nematodes often reached maximum values in the winter and appear to be correlated with minimum temperatures. Copepod abundance was related to reproductive cycles and changing sediment conditions. Copepods were abundant in the medium to coarse-grained sands, nematodes in the finer sediments. Meiofauna was greatly reduced in the lower layers of sediment; this reduction was attributed to decreased interstitial water and oxygen content.Field and laboratory results indicated specific grain size preferences of the Harpacticoida. Epigrowth feeding nematodes were dominant in sandy sediments, deposit feeders in the muds. Epigrowth dominance was probably related to carbon rich aggregated particles coating the sediments.Three distinct harpacticoid parallel level bottom communities were defined: (1) the Leptastacus macronyx (T. Scott)— Praeleptomesochra africana (Kunz) community in the submerged beach sands, (2) the Stenhelia (D.) bermudensis mihi—Typhlamphiascus lamellifer (Sars) —Cletodes dissimilis Willey community in the silty-sands and (3) the Phyllopodopsyllus hermani mihi community in the medium to coarse-grained sands.Diversity analyses of the harpacticoid communities indicated highly evolved, stable assemblages in those areas of low physical stress and less stable, variable assemblages in areas of high physical stress.Based on a thesis submitted in partial fulfillment of the requirements for the Ph. D. degree, Lehigh University, 1968. Contribution No. 82 Center for Marine and Environmental Studies, Lehigh University, Bethlehem, Pennsylvania 18015. Contribution No. 482 Bermuda Biological Station, St. George's West, Bermuda.     

Alcataenia atlantiensis n. sp. (Dilepididae) from the razorbill (Alca torda Linnaeus) in the eastern North Atlantic basin

A new species of Alcataenia is described from razorbills Alca torda Linnaeus from the southern region of the North Sea in the coastal waters of Belgium. It differs from known species of the genus in having 18–20 rostellar hooks measuring 63–74 m in length. Other attributes include a cirrus-sac 145–228 m in length, 36–49 testes and a vitelline gland measuring 114–202 × 59–112 m. This is the first species of Alcataenia described from razorbills and appears to be the only member of the genus which is endemic to the North Atlantic basin.     

Hydric constraints upon foraging in a terrestrial salamander,Desmognathus ochrophaeus (Amphibia: Plethodontidae)

Summary The time until salamanders voluntarily abandoned foraging (the water time limit) and the amount of water lost when salamanders abandoned foraging (dehydration deficit) were determined for terrestrial plethodontid salamanders, Desmognathus ochrophaeus, foraging at various vapor pressure gradients in the laboratory. Salamander activity was correlated with the rate of water loss and was inversely related to the water time limit. Animals at 0.35–0.86 kPa vapor pressure gradients abandoned foraging and returned to moist retreats significantly sooner than animals in water-saturated air. The early retreat of animals in dry air was related in part to high rates of water loss and in part to the modest dehydration deficit (3.8%) at which animals abandoned foraging. Locomotor performance and foraging ability were unaffected by dehydration until dehydration deficits exceeded 12%. This suggests that salamanders in unsaturated air abandoned foraging at a low dehydration deficit to conserve and replenish water reserves rather than to avoid outright incapacitation or death. Present address: Department of Zoology, University of Guelph, Guelph, Ontario N1G 2W1, Canada     

The effects of collembola grazing on microbial activity in decomposing leaf litter

Summary Ground leaf litter was inoculated with the fungus Coriolus versicolor and incubated in respirometers for 6 days (fresh cultures) or 33 days (senescent cultures) before different number of Folsomia candida were added. Grazing by 5 animals stimulated O₂ consumption in both series of cultures but 10, 15 or 20 animals inhibited microbial respiration. The stimulatory effect was less marked in the senescent cultures. Bacterial and fungal standing crops increased in fresh cultures during the course of the experiment but grazing by collembola increased bacterial and reduced fungal standing, crops in proportion to the grazing intensity. Microbial standing crops were not determined for senescent cultures. Microarthropod feeding activities can therefore exert a strong differential effect on fungal and bacterial populations which has not been previously recognised.     

Use of15N/14N rations to evaluate the food source of the mysid,Neomysis intermedia Czerniawsky,in a eutrophic lake in Japan

The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in ¹⁵N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in ¹⁵N was found in the mysid. The annual averages of ¹⁵N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of¹⁵N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of ¹⁵N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.     

Über die Bildung der Augenpigmentgranula beiDrosophila v undcn nach Verfütterung von Ommochromvorstufen

Zusammenfassung Bei denDrosophila-Mutantenv undcn, die weder Ommochrom noch leere Pigmentgranula aufweisen, läßt sich durch Verfüttern von Kynurenin, bzw. 3-Hydroxy-kynurenin die Bildung von Pigmentgranula induzieren, die von den Granula des Wildtyps nicht zu unterscheiden sind. Ihr größter Durchmesser beträgt ca. 0,4 , sie sind von einer Membran umgeben und ihre Wachstumsgeschwindigkeit ist identisch.Messung der heranwachsenden Granula in proximalen und distalen Bereichen der Ommatidien erbrachten einen signifikanten Größenunterschied; dieser ist bereits 48 Std nach der Verpuppung erkennbar.

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On the formation of eye pigment granules after feeding ommochrome precursors toDrosophila v andcn

Summary In the mutantsv andcn ofDrosophila, which contain neither ommochrome pigment nor empty pigment granules, feeding of kynurenine or 3-hydroxy-kynurenine causes the formation of pigment granules which cannot be distinguished from wild type granules. Their larger diameter is about 0.4 , they are surrounded by a membrane, and their growth rate is identical.Measurement of growing pigment granules in proximal and more distal regions of the ommatidia has revealed a significant difference in size which can be recognized as early as 48 hours after pupation.

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Wir danken der Deutschen Forschungsgemeinschaft für die finanzielle Unterstützung, Herrn Dr. F. G. Barth, Herrn Prof. H. Altner und seinen Mitarbeitern, sowie Frl. H. Tscharntke für Einweisung und Hilfe in der EM-Technik, und Herrn Dr. F. Schwabl für seinen Rat bei der Auswertung der Messungen.     

Yards,corridors, and mosaics: How to burn a boreal forest

Ethnographic studies have established that, until shortly after World War II, Indians in northern Alberta regularly and systematically fired habitats to influence the local distribution and relative abundance of plant and animal resources. In ways similar to what has been reported for hunter-gatherers in other regions, this pyrotechnology contributed to an overall fire mosaic that, in this case, formerly characterized northern boreal forests. Crosscultural comparisons of these practices with those in other parts of North America, as well as in several parts of Australia, illustrate functionally parallel strategies in the ways that hunter- gatherers employed habitat fires, specifically in the maintenance of fire yards and fire corridors in widely separated and different kinds of biological zones.We would like to thank Ross Wein tor his comments and suggestions on this paper, especially his ideas about the characteristics of fire mosaics as they would occur under natural conditions in boreal forests. We are also indebted to several granting agencies for funds that supported our earlier research. They include the Social Sciences and Humanities Research Council, the Museum of Man, Fire Science Center (University of New Brunswick), the Boreal Institute for Northern Studies (University of Alberta), the Australian Institute for Aboriginal Studies, and the Northern Australian Research Unit (Australian National University).     

Feeding by the aquatic heteropteran,Diplonychus rusticum (Belostomatidae): an effect of prey density on meal size

The behaviour of Diplonychus rusticum feeding on chironomid larvae has been investigated under laboratory conditions. Changes in the percentage of material extracted from prey indicated that feeding for the first two minutes enabled the predator to obtain approximately 33% of the available food; feeding for 10 minutes resulted in only 60% extraction. Comparing the percentage of each prey consumed by D. rusticum exposed to various prey densities, it was apparent that predators were more wasteful and ate less of each prey as chironomid density increased. Because the rate of food intake declined as a greater proportion of each prey was extracted, predators exposed to high chironomid densities reduced the amount of each prey consumed thereby conforming to a simple optimal feeding model.     

DNA polymorphisms in the ψβ1- and β-globin gene regions in asian macaques

DNA polymorphisms in the ₁--globin gene region in nine Asian macaques(Macaca fuscata, M. mulatta, M. nemestrina, M. cyclopis, M. fascicularis, M. arctoides, M. radiata, M. maura, andM. assamensis) were examined using several restriction endonucleases and the human ₁, IVS2, and IVS2 probes. TheBamHI site 3 to the -globin gene was polymorphic inM. fuscata andM. mulatta, while the HincII site and the EcoRI site in the ₁-globin gene region was highly polymorphic inM. fuscata andM. mulatta, respectively. These polymorphic sites also seem to be present in other Asian macaques. The present study of the polymorphism at theBamHI site 3 to the -globin gene in Asian macaques supports, at the nuclear DNA level, the idea that thefascicularis group includingM. fuscata, M. mulatta, M. cyclopis, andM. fascicularis is different from other Asian macaque groups.This study was supported in part by the Cooperation Research Program of the Primate Research Institute, Kyoto University.     

Light response of D1 turnover and photosystem II efficiency in the seagrassZostera capricorni

Biochemical and biophysical parameters, including D1-protein turnover, chlorophyll fluorescence, oxygen evolution activity and zeaxanthin formation were measured in the marine seagrassZostera capricorni (Aschers) in response to limiting (100 mol·m^–2·^–1), saturating (350 mol·m^–2·s^–1) or photoinhibitory (1100 mol·m^–2·s^–1) irradiances. Synthesis of D1 was maximal at 350 mol·m^–2·s^–1 which was also the irradiance at which the rate of photosynthetic O₂ evolution was maximal. Degradation of D1 was saturated at 350 mol·m^–2·s^–1. The rate of D1 synthesis at 1100 mol·m^–2·s^–1 was very similar to that at 350 mol·m^–2·s^–1 for the first 90 min but then declined. At limiting or saturating irradiance little change was observed in the ratio of variable to maximal fluorescence (Fv/Fm) measured after dark adaptation of the leaves, while significant photoinhibition occurred at 1100 mol·m^–2·s^–1. The proportion of zeaxanthin in the total xanthophyll pool increased with increasing irradiance, indicative of the presence of a photoprotective xanthophyll cycle in this seagrass. These results are consistent with a high level of regulatory D1 turnover inZostera under non-photoinhibitory irradiance conditions, as has been found previously for terrestrial plants.We would like to thank Professor Peter Böger (Department of Plant Biochemistry, University of Konstanz, Germany) for the kind gift of D1 antibodies. This work was partly supported by a University of Queensland Enabling Grant to CC.