Study on immunobiology in endoparasites of public health interest: echinococcosis-hydatidosis

Cystic echinococcosis caused by Echinococcus granulosus is one of the most widespread zoonoses in the Mediterranean, endemic in some regions such as Sardinia. Some aspects of the research conducted in this area are briefly reviewed for an integrated analysis of both epidemiological and immunobiological knowledge, gained from field observations and experimental studies. Data on epidemiology in intermediate hosts, immunological assessment of exposure in humans, immune response and Th1/Th2 polarization in secondary experimental hydatidosis, kinetics of response in definitive host and cytokine production in experimental models are briefly reported. They confirm the usefulness of an immunobiological approach both in intermediate and definitive hosts and their potential in prevention, monitoring and control of E/H.     

Effect of hyaluronic acid on human chondrocyte cell lines from articular cartilage

The effects of hyaluronic acid (HA) derivative on the proliferation and metabolism of human chondrocytes were examined. Cells were obtained from cartilage from metatarsal phalangeal joints of 20 adult humans (aged 22-63) and from femoral knee condyles of 10 subjects (aged 22-77). Chondrocytes isolated by collagenase/Dnase digestion were cultured with addition of different doses of HA for 4 weeks. Morphological studies demonstrated that HA enhanced the adhesion of cells to substrate; HA-treated chondrocytes proliferated better than chondrocytes cultured in HA-free medium. This study shows that HA improves in vitro substrate adhesion ability and proliferative activity of human cartilage cells and that the response to the treatment varies on an individual basis.     

西双版纳不同热带森林下土壤氮矿化和硝化作用研究

 1998年7月,用埋袋法对西双版纳热带季节雨林、崖豆藤(Mellettia leptobotrya)次生林、季节雨林内林窗和轮歇地土壤的氮矿化和硝化作用进行了研究。研究结果表明季节雨林和崖豆藤次生林的格局基本相同,氮净矿化速率分别为6.55mgN·kg-1·30d-1和6.37mgN·kg-1·30d-1,硝化速率分别为16.28mgN·kg-1·30d-1和16.38mgN·kg-1·30d-1。而林窗下和轮歇地土壤的氮净矿化速率和硝化速率均为负值,氮净矿化速率分别为–7.85mgN·kg-1·30d-1和–10.69mgN·kg-1·30d-1,硝化速率分别为–2.78N·kg-1·30d-1和–3.69mg N·kg-1·30d-1。从实验结果看,在30d的培养过程中,NH4–N消耗较多,导致硝化速率大于氮净矿化速率。     

Separation and quantitation of metallothionein isoforms from liver of untreated rats by ion-exchange high-performance liquid chromatography and atomic absorption spectrometry

A sensitive method for determination of metallothionein (MT) isoform levels in rat liver by ion-exchange high-performance liquid chromatography and atomic absorption spectrometry was developed. Critical steps in sample preparation, like MT extraction, MT saturation with Cd and protein separation, were optimized. This method is capable of measuring levels of 2.0 μg/g liver for metallothionein-1 (MT-1) and 1.3 μg/g liver for metallothionein-2 (MT-2), respectively, with a high recovery of 103% on average. The method described, thus, proved suitable for analyzing metallothionein isoform concentrations even in untreated animals. The ratio of MT-1 to MT-2 was found to be 1:1 on average. MT decomposition during storage was very high in whole livers, but could be reduced by about 80% when extracted liver samples were used.     

Zooplankton Successions in Neighboring Lakes with Contrasting Impacts of Amphibian and Fish Predators

Two pairs of neighboring subalpine lakes located in the Northern Calcareous Alps of Austria were investigated. Each pair comprised a deeper lake containing European minnows (Phoxinus phoxinus ), and a corresponding shallower lake harboring Alpine newts (Triturus alpestris ) as top predators. Plankton successions within fish and amphibian lakes differed markedly from each other. Throughout the year rotifers numerically dominated within the minnow lakes, while pigmented copepods (Genera Heterocope, Acanthodiaptomus , Arctodiaptomus , Mixodiaptomus ) and Daphnia were prominent in the amphibian lakes, at least early during the ice‐free period. We argue that size‐selective predation by minnows was the ultimate reason for this predominance of smaller zooplankton. While one of the minnow lakes was characterized by a succession of spatially and temporally segregated rotifer species, the other minnow lake permitted the development of populations of small‐sized Bosmina and Ceriodaphnia during summer, probably due to the existence of a strong oxycline allowing zooplankton crustaceans to avoid predation from shore‐based shoals of minnows. Once trout were introduced into this lake, minnows were visibly reduced in abundance. Bosmina and Ceriodaphnia disappeared and Daphnia together with a predacious copepod (Heterocope ) emerged either from egg banks or arrived from nearby source populations. We argue that the crustacean communities within the fishless lakes were adapted to the comparatively weak predation rates of Alpine newts. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Unexpected specificity in the thioredoxin activation of fructose-bis-phosphatases from different plants

Green seedlings of soy bean and wheat contain, like the plant seeds, multiple thioredoxin proteins which possess all typical thioredoxin properties but are inactive in the stimulation assay with spinach fructose-bis-phosphatase. However the pure proteins do have thioredoxin f activity when tested with homologous enzymes isolated from soy bean or wheat leaves, respectively, in the presence of Mg++. This new type of species specificity, unknown in all other in vitro assays of reduced thioredoxins, has to be considered in characterizing complete thioredoxin profiles in plants.     

PEG-immobilization of cardol and soluble polymer-supported synthesis of some cardol–coumarin derivatives: Preliminary evaluation of their inhibitory activity on mushroom tyrosinase

In this work, the PEG-immobilization and the liquid phase synthesis of some coumarins derived from cardol are presented. Some preliminary results on their tyrosinase inhibitory activity are also included.     

Enhanced production of undecylprodigiosin in Streptomyces coelicolor by co-cultivation with the corallopyronin A-producing myxobacterium,Corallococcus coralloides

Prolific producers of natural products like streptomycetes and myxobacteria live in complex natural frameworks consisting of many microorganisms. Presumably intricate physiological and metabolic regulatory networks have evolved to enable the organisms to respond to intra- and interspecies interactions, e.g. biosynthesis of specific natural products is up-regulated due to competitors in the surrounding area. The soil-dwelling bacterium, Streptomyces coelicolor, produces the biologically-active compound, undecylprodigiosin (Red). Co-incubation with the corallopyronin A-producer, Corallococcus coralloides, was performed to explore the hypothesis that Red production can be enhanced by a myxobacterial competitor. Co-cultivation resulted in earlier onset and increased production of Red (60-fold increase of the intra-cellular concentration). Using different Corallococcus-derived extracts for elicitation, revealed that water-soluble factors triggered the enhanced production of Red which shows antimicrobial, immunosuppressive and anticancer properties.