Significant extension in northern Australia of the known geographic range of the Shield Shrimp Triops australiensis (Crustacea: Notostraca)

The program BIOCLIM predicts the total geographic distribution of species, based upon the biogeoclimatic characteristics common to the localities at which they are known to occur. Field studies in the Northern Territory have located the Shield Shrimp Triops australiensis at localities substantially north of its known and predicted geographic distribution.     

Misting and nitrogen fertilization of shoots of a saltmarsh grass: effects upon fungal decay of leaf blades

We conducted a 12-week field manipulation experiment in which we raised the nitrogen availability (ammonium sulfate fertilization to roots) and/or water potential (freshwater misting) of decaying leaf blades of a saltmarsh grass (smooth cordgrass, Spartina alterniflora) in triplicate 11-m² plots, and compared the manipulated plots to unmanipulated, control plots. The ascomycetous fungi that dominate cordgrass leaf decomposition processes under natural conditions exhibited a boosting (>2-fold) of living standing crop (ergosterol content) by misting at the 1 st week after tagging of senescent leaves, but afterwards, living-fungal standing crop on misted blades was equivalent to that on control blades, confirming prior evidence that Spartina fungi are well adapted to natural, irregular wetting. Misting also caused 2-fold sharper temporal declines than control in instantaneous rates of fungal production (ergosterol synthesis), 5-fold declines in density of sexual reproductive structures that were not shown by controls, and 2-fold higher rates of loss of plant organic mass. Extra nitrogen gave a long-term boost to living-fungal standing crop (about 2-fold at 12 weeks), which was also reflected in rates of fungal production at 4 weeks, suggesting that saltmarsh fungal production is nitrogen-limited. Although bacterial and green-microalgal crops were boosted by manipulations of nitrogen and/or water, their maximal crops remained 0.3 or 2% (bacteria or green microalgae, respectively) of contemporaneous living-fungal crop. The fungal carbon-productivity values obtained, in conjunction with rates of loss of plant carbon, hinted that fungal yield can be high (>50%), and that it is boosted by high availability of nitrogen. We speculate that one partial cause of high fungal yield could be subsidy of fungal growth by dissolved organic carbon from outside decomposing leaves.     

The distribution and colocalization of neuropeptides and catecholamines in nerves supplying the gall bladder of the toad,Bufo marinus

The indirect immunofluorescence technique was used to determine the distribution of peptide-containing axons in the gall bladder of the cane toad, Bufo marinus. In addition, the adrenergic innervation of the gall bladder was examined by use of immunoreactivity to the catecholamine-synthesizing enzyme, tyrosine hydroxylase, and glyoxylic acid-induced fluorescence. On the basis of peptide coexistence, two intrinsic populations of neurones and their projecting fibres could be distinguished substance P neurones and vasoactive intestine peptide neurones. Neither of these two types of neurones contained any other colocalized neuropeptides. Four populations of nerve fibres arising from cell bodies outside the gall bladder were identified: nerves containing colocalized galanin, somatostatin and vasoactive intestinal peptide; nerves containing colocalized calcitonin gene-related peptide and substance P; adrenergic nerves containing neuropeptide Y; and nerves containing only adrenaline.     

Ecomethodology for organoosmotrophs: Prokaryotic unicellular versus eukaryotic mycelial

Although they are very unlikely to play large direct roles in water-column microbial loops, eukaryotic mycelial decomposers (the mycelial true fungi, eumycotes, and zoosporic fungi, oomycotes) have the potential to be important secondary producers in decaying plant material in shallow aquatic systems. Their secondary productivity may lead to important exchanges of material with microbial loops: output of ascospores, conidia, zoosporic flagellates, leaked lysates, and particles of decayed plants containing mycelium; input of dissolved organics and inorganic nutrients. Development of methods for ecological study of the aquatic mycelial eukaryotic decomposers has not advanced as rapidly as that for the prokaryotes of microbial loops, probably because (1) there are fewer aquatic microbial ecologists with mycological training and inclination than with prokaryotic leanings; and (2) the mycelial decomposers are difficult to work with, because they produce their mycelial mass virtually entirely within opaque solid substrates. Direct microscopic methods have emerged as prime tools for the measurement of prokaryotic mass, whereas an index-chemical assay (ergosterol) is currently the most efficient way to measure the mass of eumycotes. For measuring productivity of prokaryotes of microbial loops, microbial ecologists may choose from several (>10) published and field-tested methods, involving direct microscopy or monitoring of radiotracers. Extensive reviews of distribution and dynamics of aquatic bacterial mass and productivity have appeared. For measuring productivity of eukaryotic mycelial decomposers, one has only two published methods from which to choose, a direct-microscopic and a radiotracer method, neither of which has had adequate field testing. We are, furthermore, much less well equipped to obtain mass and productivity information for the poorly known mycelial oomycotes than we are for the eumycotes. Application of productivity techniques and nucleic-acid technology, may within the next decade allow knowledge of ecology of aquatic eukaryotic mycelial decomposers to advance to levels approaching that for the prokaryotes of microbial loops.     

Relation between infection with Helicobacter pylori and living conditions in childhood: evidence for person to person transmission in early life.

OBJECTIVES--To relate the prevalence of infection with Helicobacter pylori in adults to their living conditions in childhood to identify risk factors for infection. DESIGN--Prevalence study of IgG antibodies to H pylori (> 10 micrograms IgG/ml, determined by enzyme linked immunosorbent assay (ELISA)) and reported living conditions and other socioeconomic factors in childhood. SETTING--Three factories in Stoke on Trent. SUBJECTS--471 male volunteers aged 18 to 65 years. MAIN OUTCOME MEASURES--Seroprevalence and variables in childhood. RESULTS--Seroprevalence of H pylori increased with age (22/74 (29.7%) at < 30 years v 29/46 (63%) at 55-65 years; P < 0.001 for trend) and was related to manual occupation (14/65 (21.5%) for non-manual v 162/406 (39.9%) for manual; P = 0.003). After data were adjusted for age and occupation subjects from large families, whose childhood homes were crowded or who regularly shared a bed in childhood, were significantly more likely to be seropositive (adjusted odds ratio (95% confidence interval) 2.15 (1.41 to 3.30) for crowding and 2.13 (1.38 to 3.30) for sharing a bed), but there was no relation with possession of a bathroom, inside toilet, refrigerator, or household pets in childhood. CONCLUSIONS--Close person to person contact in childhood is an important determinant of seroprevalence of H pylori in adulthood, suggesting that the infection is transmitted directly from one person to another and may be commonly acquired in early life.     

Guanine nucleotide regulatory protein alterations in young Milan hypertensive strain rats

Vascular smooth muscle cell membranes from prehypertensive rats of the Milan hypertensive strain (MHS) were used to examine adenylyl cyclase activity and its regulation by guanine nucleotide regulatory proteins (G-proteins). Basal adenylyl cyclase activity was similar in MHS and Milan normontensive strain (MNS) membranes. Forsokolin (10^?4 M) produced a significantly greater stimulatory response in MHS membranes, but this was not observed with NaF (10^?2 M). Isoporterenol (10^?4 M) caused a significantly decreased stimulation of adenylyl cyclase activity in MHS membranes, while prostaglandin E₁ (10^?5 M) produced similar responses in the two strains. G_i function and GTP responses, as observed by biphasic effects of GTP on isoproterenol-stimulated membranes, were similar in both strains. The levels of G_i2α and G_qα/G₁₁α were similar in the two strains, while the levels of G_sα (44 and 42 kDa forms) and the β-subunit were significantly reduced by ～20% in MHS membranes. The α-subunit of G_i3 was dramatically reduced by ～80% in MHS membranes. The affinities of β-adrenergic receptors for the antagonist, cyanophindolol, were similar in the two strains; however, the number of β-adrenoceptors was substantially reduced in MHS membranes. These findings may be of relevance to altered vascular reactivity and transmembrane ion distribution observed in the MHS.     

Regional Distribution and Quantitative Measurement of the Phosphoinositidase C-Linked Guanine Nucleotide Binding Proteins G1α and Gqα in Rat Brain

Abstract: Levels of the guanine nucleotide binding proteins G₁₁α and G_qα, which produce receptor regulation of phosphoinositidase C., were measured immunologically in 13 regions of rat central nervous system. This was achieved by immunoblotting membranes from these regions with antisera (CQ series) that identify these two polypeptides equally, following separation of the membranes using sodium dodecyl sulphate-polyacrylamide gel electrophoresis conditions that can resolve G_qα and G₁₁α. In all regions examined, G_qα was more highly expressed than G₁₁α. Ratios of levels of G_qα to G₁₁α varied between the regions from 5:1 to 2:1. Quantitative measurements of the levels of G_qα and G₁₁α in each region were obtained by comparison with known amounts of purified liver G_qα and G₁₁α and with E. coli expressed recombinant G_qα. Areas that expressed G_qα highly included olfactory bulb (930 ng/ mg of membrane protein), frontal cortex (700 ng/mg of membrane protein), parietal occipital cortex (670 ng/mg of membrane protein), caudate putamen (1,003 ng/mg of membrane protein), hippocampus (1,045 ng/mg of membrane protein), hypothalamus (790 ng/mg of membrane protein), and cerebellum (950 ng/mg of membrane protein). More modest levels were observed in thalamus (450 ng/mg of membrane protein), pituitary (480 ng/mg of membrane protein), optic chiasma (330 ng/mg of membrane protein), and spinal cord (350 ng/mg of membrane protein). Gna was more evenly expressed with values ranging from about 170 ng/mg of membrane protein in spinal cord and optic chiasma to close to 300 ng/mg of membrane protein in regions expressing high levels of G_qα. A third polypeptide could be identified by the CQ antisera in all brain regions. The possibility that this polypeptide is the α subunit of G₁₄ is discussed.     

Getting to the root of the problem: new evidence for the use of plant root foods in Mesolithic hunter-gatherer subsistence in Europe

Vegetation History and Archaeobotany - This paper presents new evidence for the harvesting of edible plant roots and tubers at Northton, a Mesolithic hunter-gatherer site on Harris, in the Western...