Haemaphysalis concinna Koch, 1844 in Italy

The authors provide here the data concerning the first italian finding of tick Hemaphysalis concinna (Ixodidae). Two males of this species--which has a large geographic diffusion--were actually caught for the first time in Italy, in July 1977. They were found on the ground of the Castel Porziano estate (Rome) at sealevel, in two different grassy places. The authors describe their morphological characters and provide some essential data on the environment of Castel Porziano.     

A high throughput assay for inhibitors of HIV-1 protease. Screening of microbial metabolites

A novel method for discovery of HIV-1 protease inhibitors in complex biological samples has been developed. The assay is based on two specific reagents: a recombinant protein constituted by a portion of the HIV-1 Gag polyprotein comprising the p17-p24 cleavage site, fused to E. coli beta-galactosidase, and a monoclonal antibody which binds the fusion protein in the Gag region. Binding occurs only if the fusion protein has not been cleaved by the HIV-1 protease. The assay has been adapted for the screening of large numbers of samples in standard 96-well microtiter plates. Using this method about 12000 microbial fermentation broths have been tested and several HIV-1 protease inhibitory activities have been detected. One of these has been studied in detail.     

Comparative study of Langerhans cells in normal and pathological human scars. I. Atrophic scars.

In the present study, we investigated Langerhans cells (LCs) in the epidermal component of human atrophic scars, comparing them with those in control skin and normotrophic scars. A preliminary analysis of the histological features was first carried out on vertical serial sections, stained with hematoxylin and eosin. The total epidermal thickness and the thickness of the single epidermal layers were then measured, by means of a digitizing tablet and a morphometric program run on an Apple IIe computer. These parameters were found to be significantly lower (40%) in atrophic scars, if compared to control skin and normotrophic scars (p less than 0.05). CDla-positive and HLA-DR-positive LCs were marked by indirect immunofluorescence. Their position among the epidermal layers, their dimensions, their density and their morphology were examined. In atrophic scars, LCs were densely and evenly distributed in all the epidermal layers. Their density was increased (about 1200 cells/mm2 of epidermal area), if compared to control skin and normotrophic scars (both 300-400 cells/mm2 of epidermal area; p less than 0.001). The CDla-positive definite cell bodies, exhibiting an unstained nucleus, were as large as those evidentiated in the normotrophic scars and twice as much the control skin values (p less than 0.001). The present results provide morphological data that distinguish atrophic scars from control skin and normotrophic scars, and suggest an involvement of the Langerhans cells in this particular case of pathological scarring.     

Structural investigation of the capsular polysaccharide of klebsiella serotype K26

The structure of the capsular polysaccharide from Klebsiella K26 has been determined by using the techniques of methylation, periodate oxidation, partial hydrolysis, and β-elimination. N.m.r. spectroscopy (¹H and ¹³C) was used to establish the nature of the anomeric linkages and to identify oligosaccharides obtained by the different degradative techniques employed.The polysaccharide is comprised of repeating units of the heptasaccharide shown.

     

Dictyocaulus viviparus: The role of pepsin in the exsheathment of infective larvae

Following the report of Silverman and Podger (1964) that pepsin formed an association with larval receptor sites on D. viviparus and that exsheathment had an absolute requirement for pepsin, the role of pepsin was studied in greater detail. A range of enzyme incubation, pepsin labeling, histochemical and electron microscopical techniques were used. Pepsin did cause exsheathment of D. viviparus but, it was not an absolute requirement. Exsheathment occurred in a range of proteolytic enzymes each at its optimum pH. Findings suggest that the area of weakness around the anterior end of the larvae is digested by external protease and that, in vivo, exsheathment is caused by the gut enzymes of the host.     

Chelating derivatives of chitosan obtained by reaction with ascorbic acid

Ascorbic acid immediately dissolves Euphausia superba chitosan upon mixing and forms chitosan ascorbate; during the 6-h period after dissolution in water at pH 5–7, ascorbate is oxidized to dehydroascorbate which undergoes Schiff reaction with the amino groups of chitosan, thus yielding a viscous solution of a polymeric ketimine. The latter is characterized by infrared spectrometry, circular dichroism spectropolarimetry, viscometry and alkalimetry. When brought into contact with transition metal ions, the chitosan ascorbate ketimine yields insoluble metal chelates. Upon reduction with sodium cyanoborohydride, the water-insoluble N-[2-(1,2-dihydroxyethyl)tetrahydrofuryl] chitosan (NDTC) is obtained, which shows enhanced capacity for uranium, up to 800 mg U/g from solutions at pH 4·5.     

High CO2 concentration and iron availability determine the metabolic inventory in an Emiliania huxleyi-dominated phytoplankton community

Ocean acidification (OA), a consequence of anthropogenic carbon dioxide (CO₂) emissions, strongly impacts marine ecosystems. OA also influences iron (Fe) solubility, affecting biogeochemical and ecological processes. We investigated the interactive effects of CO₂ and Fe availability on the metabolome response of a natural phytoplankton community. Using mesocosms we exposed phytoplankton to ambient (390 μatm) or future CO₂ levels predicted for the year 2100 (900 μatm), combined with ambient (4.5 nM) or high (12 nM) dissolved iron (dFe). By integrating over the whole phytoplankton community, we assigned functional changes based on altered metabolite concentrations. Our study revealed the complexity of phytoplankton metabolism. Metabolic profiles showed three stages in response to treatments and phytoplankton dynamics. Metabolome changes were related to the plankton group contributing respective metabolites, explaining bloom decline and community succession. CO₂ and Fe affected metabolic profiles. Most saccharides, fatty acids, amino acids and many sterols significantly correlated with the high dFe treatment at ambient pCO₂. High CO₂ lowered the abundance of many metabolites irrespective of Fe. However, sugar alcohols accumulated, indicating potential stress. We demonstrate that not only altered species composition but also changes in the metabolic landscape affecting the plankton community may change as a consequence of future high-CO₂ oceans.