A POLARLY FLAGELLATED MEMBER OF THE ENTEROBACTERIACEAE

SUMMARY: An organism which has been frequently isolated from the rhizosphere of plants of Lolium perenne (Perennial Rye-grass) is described; it has the typical morphology and flagellation of Pseudomonas but the biochemical reactions of Klebsiella.     

Observed relationships between El Niño‐Southern Oscillation,rainfall variability and vegetation and fire history on Halmahera,Maluku, Indonesia

A temporally high‐resolution palynological study of the uppermost section of core MD98‐2180 from Kau Bay, Halmahera, Indonesia, provides a vegetation and fire record covering the last 250 years. The record is compared with the Maluku Rainfall Index, Southern Oscillation Index (SOI) and southern hemisphere winter sea surface temperatures (SST) for the central Pacific Ocean based on instrumental data, as well as reconstructions of the SOI and the central Pacific SST and historically recorded El Niño events. The results show that significant El Niño events are generally associated with increased representation of Dipterocarpaceae pollen, probably reflecting the mass‐flowering of this taxon during El Niño‐Southern Oscillation (ENSO) droughts, and elevated charcoal levels, reflecting a greater incidence of fires during these extremely dry periods, while humid phases show increased fern numbers. Our findings demonstrate that pollen records ‘ecological’ in scale can provide useful additional proxy records of ENSO events.     

A migration-selection model for the morph frequency variation in the peppered moth over England and Wales

A migration-selection model for the spatial and temporal variation of morph frequencies over England and Wales for the peppered moth has been constructed. The morph frequencies have been obtained by computer simulation using the model for various assumptions regarding selection and migration within the boundaries of experimental observation. The selection, in this case, has been assumed to be wholly caused by bird predation and non-visual selection is taken to be same for all phenotypes. The results are compared with available experimental data along three transects. Reasonable agreement with the data is obtained for the Manchester-North Wales transect and the South Wales-London transect. The simulation fails, on the other hand, to reproduce observations along the Central Wales-Birmingham-East Anglia transect. Thus it is concluded that the hypothesis ol balance of selection and migration is untenable as it stands. Either the visual selection pressures are incorrectly or incompletely specified, or else non-visual selection is also operating.     

Tympanal organs of geometrid moths: a review of their morphology, function, and systematic importance

Abstract. The basic components of the tympanal organs of Geometridae are described against the background of the relevant literature. The work is prefaced by a summary of the occurrence of hearing organs within adult Lepidoptera as a whole, and the systematic value of these structures is assessed. A Latin-based nomenclature is proposed to standardize the terminology. An assessment of the morphological variation of these organs within the Geometridae was based on the study of over 230 species representing numerous examples from all the subfamilies. Morphological variation between and within the geometrid subfamilies is discussed.     

The oviduct musculature of the horsefly, Tabanus sulcifrons, and its response to 5-hydroxytryptamine and proctolin

ABSTRACT. A delicate lace-like membrane covers the ovaries of Tabanus sulcifrons. These membranes were found to contain muscle fibres that provide the organs with motile properties. The lateral oviducts consist of a single layer of longitudinal muscles that form a structural syncytium by means of an extensive anastomosis of the fibres comprising it. The common oviduct is composed of two muscle layers, an outer sheath of circular muscle and an inner substratum of longitudinal muscle. Both of these layers showed evidence of a structural syncytium. When isolated in saline, the oviduct was spontaneously active and gave a simple phasic pattern of contraction. Such muscle preparations were sensitive to both 5-hydroxytryptamine (5HT) and the insect myotropic peptide, proctolin. Excitation was generally indicated by a rise in muscle tonus or an increase in the frequency and amplitude of individual phasic contractions, or all three characteristics. The threshold for activation with 5HT was variable, ranging from as low as 4 × 10^-9M to 1 × 10^-7M. Proctolin evoked a noticeable increase in the tonus of most oviducts at 10^-10M. However, several preparations responded to as little as 3 × 10^-11M proctolin.     

FIELD STUDIES OF HOMING IN THE PULMONATE SLUG LIMAX PSEUDOFLAVUS (EVANS)

Excursions of Limax pseudoflavus (Evans) were recorded over9 days using time lapse cinematography. Excursions were madeat night, ending before sunrise, and were significantly morefrequent in wet than in dry weather. The homes of these slugsare species rather than population or individual specific. Animalstended to home upwind but the direction in which they left homewas not significantly correlated with wind direction. Trailfollowing may be involved in homing. All but one example ofhoming may be interpreted in terms of distant chemoreception,rheotaxis and trail following. Using these mechanisms alonea slug's best strategy for feeding and homing is discussed. (Received 15 March 1979;     

Role of Energized States of (Na<Superscript>+</Superscript> + K<Superscript>+</Superscript>-ATPase in the Sodium Pump

IN an earlier paper¹ we have presented a model for a sodium pump based on the operation of the adenosine triphosphatase component of membranes which is sensitive to ouabain and is activated by sodium and potassium; that is (Na⁺+K⁺)-ATPase. We attempted to correlate the biochemical properties of this enzyme system as they were then known with the essential properties of Na⁺ transport systems. The model suggested further experiments which could clarify the role of (Na⁺ + K ⁺)-ATPase in ion transport and some experimental evidence is now available for the stoichiometry of ouabain binding to isolated enzyme preparations^2,3 although differences in the experimental techniques which have been used make the data equivocal.