Proteomic characterization of adipose tissue constituents, a necessary step for understanding adipose tissue complexity

The original concept of adipose tissue as an inert storage depot for the excess of energy has evolved over the last years and it is now considered as one of the most important organs regulating body homeostasis. This conceptual change has been supported by the demonstration that adipose tissue serves as a major endocrine organ, producing a wide variety of bioactive molecules, collectively termed adipokines, with endocrine, paracrine and autocrine activities. Adipose tissue is indeed a complex organ wherein mature adipocytes coexist with the various cell types comprising the stromal-vascular fraction (SVF), including preadipocytes, adipose-derived stem cells, perivascular cells, and blood cells. It is known that not only mature adipocytes but also the components of SVF produce adipokines. Furthermore, adipokine production, proliferative and metabolic activities and response to regulatory signals (i.e. insulin, catecholamines) differ between the different fat depots, which have been proposed to underlie their distinct association to specific diseases. Herein, we discuss the recent proteomic studies on adipose tissue focused on the analysis of the separate cellular components and their secretory products, with the aim of identifying the basic features and the contribution of each component to different adipose tissue-associated pathologies.     

A new genus of Syllidae (Polychaeta) from Western Australia

During a study carried out on the subfamily Exogoninae (Syllidae) from Australia, several specimens of a new genus and species were found in samples of dead coral substrate from Western Australia. They have long palps, fused except for a terminal notch, long median and two short lateral antennae, a single pair of short tentacular cirri, and short dorsal cirri, somewhat longer than the parapodial lobes. These characters resemble those of the genus Exogone Örsted, 1845. However, all these appendages are articulated. The chaetae are very similar to those of several species of Syllis Lamarck, 1818, having coarse spines on the margin of compound chaetal blades and truncated dorsal simple chaetae. Furthermore, the pharynx begins in chaetiger 3, posterior to the peristomium, as in many species of the genus Syllis; this condition does not occur in any described species of Exogone. The new genus is provisionally proposed to belong to the subfamily Syllinae, although it has some characters typical of the Exogoninae. Examination under the SEM shows another peculiar feature, the nuchal organs are distinctly laterally located. Within the Syllinae, only Paratyposyllis Hartmann-Schröder, 1962 has a single pair of tentacular cirri, but in that genus, the palps are only basally fused.     

Metabolic engineering of isoprenoid biosynthesis in Arabidopsis for the production of taxadiene, the first committed precursor of Taxol

Paclitaxel (Taxol) is a widely used anticancer isoprenoid produced by the secondary metabolism of yew (Taxus sp.) trees. However, only limited amounts of Taxol or related metabolites (taxoids) can be obtained from the currently available sources. In this work we have taken the first step toward genetically engineering the biosynthesis of taxoids in angiosperms. The first committed step in Taxol biosynthesis is the production of taxadiene from geranylgeranyl diphosphate (GGPP), catalyzed by the plastid-localized enzyme taxadiene synthase (TXS). A recombinant T. baccata TXS lacking the putative plastid targeting peptide and fused to a C-terminal histidine (His) tag was shown to be enzymatically active in Escherichia coli. Constitutive production of the full-length His-tagged enzyme in Arabidopsis thaliana plants led to the accumulation of taxadiene and concomitant growth retardation and decreased levels of photosynthetic pigment in transgenic plants. Although these phenotypes may derive from a toxic effect of taxadiene, the lower accumulation of endogenous plastid isoprenoid products such as carotenoids and chlorophylls in transgenic plants also suggests that the constitutive production of an active TXS enzyme might alter the balance of the GGPP pool. Induction of transgene expression using a glucocorticoid-mediated system consistently resulted in a more efficient recruitment of GGPP for the production of taxadiene, which reached levels 30-fold higher than those in plants constitutively expressing the transgene. This accomplishment illustrates the possibility of engineering the production of taxoids and other GGPP-derived isoprenoids in crop plants despite the constraints associated with limited knowledge with regard to regulation of GGPP availability.     

Molecular mechanisms for environmentally induced and evolutionarily rapid redistribution (plasticity) of meiotic recombination

It has long been known (circa 1917) that environmental conditions, as well as speciation, can affect dramatically the frequency distribution of Spo11/Rec12-dependent meiotic recombination. Here, by analyzing DNA sequence-dependent meiotic recombination hotspots in the fission yeast Schizosaccharomyces pombe, we reveal a molecular basis for these phenomena. The impacts of changing environmental conditions (temperature, nutrients, and osmolarity) on local rates of recombination are mediated directly by DNA site-dependent hotspots (M26, CCAAT, and Oligo-C). This control is exerted through environmental condition-responsive signal transduction networks (involving Atf1, Pcr1, Php2, Php3, Php5, and Rst2). Strikingly, individual hotspots modulate rates of recombination over a very broad dynamic range in response to changing conditions. They can range from being quiescent to being highly proficient at promoting activity of the basal recombination machinery (Spo11/Rec12 complex). Moreover, each different class of hotspot functions as an independently controlled rheostat; a condition that increases the activity of one class can decrease the activity of another class. Together, the independent modulation of recombination rates by each different class of DNA site-dependent hotspots (of which there are many) provides a molecular mechanism for highly dynamic, large-scale changes in the global frequency distribution of meiotic recombination. Because hotspot-activating DNA sites discovered in fission yeast are conserved functionally in other species, this process can also explain the previously enigmatic, Prdm9-independent, evolutionarily rapid changes in hotspot usage between closely related species, subspecies, and isolated populations of the same species.     

Hydrolysis of adenylyl(2'-5')adenosine in chick embryo sera

Similar to adult chick sera in chick embryo sera the enzyme activity hydrolyzing the core of the dimer of A-5A - adenylyl(2' -5')adenosine is present. The enzyme activity possesses the same properties in both sera. Heating of the serum to 60 degrees C for 30 minutes does not affect the enzyme activity. A marked decrease in activity occurs after heating of the serum to above 65 degrees C. Hydrolysis of A2' p5' A in the serum is more efficient under alkaline conditions (pH 9-10) than at physiological pH 7.2-7.4.     

A diterpene acid from baccharis tucumanensis

The new clerodane diterpene 1 was isolated from the aerial parts of Baccharis tucumanensis (Compositae). Its structure has been determined from spectral data combined with chemical transformations.     

Presence of polioviruses and other enteral viruses in sewage: a survey in the Czech Socialistic Republic 1969-1976

Monitoring polioviruses in sewage is a permanent task within the poliomyelitis vaccination control programme in Czechoslovakia. The results of sewage examination in certain localities of the CSR in the years 1969 to 1976 are reported. During the study years, nearly 3600 samples of sewage were examined. The yield was about 9 percent of samples positive for polioviruses and 22 per cent of samples positive for other viruses. The virus positivity rate was roughly the same in samples from municipal sewers and samples from children's facilities. The majority of polioviruses were detected within 3 to 4 months after mass vaccination campaigns, which in Czechoslovakia are carried out in spring. In some years types 2 and 3 polioviruses tended to occur in later months after vaccination as well. Antigenic characterization of the polioviruses isolated in Prague showed that polioviruses possessing an rct+ marker and antigenically related but not identical with the original vaccine strains were sometimes present late during the intervals between vaccination campaigns. It may be assumed that vaccine strains which have been in circulation for sufficiently long time are subject to a gradual change or that vaccine-like strains have been imported.     

Aluminium Stress Affects Nitrogen Fixation and Assimilation in Soybean (Glycine max L.)

Nitrogen fixation and assimilation in nodules and roots were studied in soybean (Glycine max L.) exposed to different levels of aluminium (Al) stress (0, 50, 200 and 500 μM). Al at 500 μM induced oxidative stress, which became evident from an increase in lipid peroxidation accompanied by a concomitant decline in antioxidant enzyme activities and leghaemoglobin breakdown. Consequently, there was also a reduction in nitrogenase activity. However, the leghaemoglobin levels and nitrogenase activity were unexpectedly found to be higher in nodules when the plants were treated with 200 μM Al. Of the enzymes involved in nitrogen assimilation, the activity of glutamate dehydrogenase-NADH was reduced in nodules under Al stress, but it was significantly higher in roots at 500 μM Al as compared to that in the control. In nodules, the glutamine synthetase/glutamate synthase-NADH pathway, assayed in terms of activity and expression of both the enzymes, was inhibited at >50 μM Al; but in roots this inhibitory effect was apparent only at 500 μM Al. No significant changes in ammonium and protein contents were recorded in the nodules or roots when the plants were treated with 50 μM Al. However, Al at ≥200 μM significantly increased the ammonium levels and decreased the protein content in the nodules. But these contrasting effects on ammonium and protein contents due to Al stress were observed in the roots only at 500 μM Al. The results suggest that the effect of Al stress on nitrogen assimilation is more conspicuous in nodules than that in the roots of soybean plants.     

Immunohistological signposts in central nervous system tumours with neuronal differentiation.

25 neuronal tumours with a panel of antibodies were studied and it was found that vimentin was present in 15 tumours. It was also found in a few cells within rosettes. PGP 9.5 showed a somatic pattern of staining with nuclear and perinuclear positivity in 23. Neurofilament reactivity was found in 14. Retinal S-antigen was detected only in one medulloblastoma, 3/4 pineal tumours and 2/2 retinoblastomas. Reactivity, for synaptophysin was present in 2/5 medulloblastomas, 3/10 neuroblastomas and 2/2 retinoblastomas. GFAP was demonstrated in scattered tumour cells in 4/5 medulloblastomas. Two of these were the only tumours featuring bipolar differentiation whilst it was unipolar in the remainder. The significance of these findings in relation to the ontogeny of these tumours is discussed.