Concentration and Composition of Serum and Plasma Glycosaminoglycans in Domestic Animal Species

Acid glycosaminoglycans (GAGs) were isolated from serum and/or plasma of some domestic animals and the composition of the isolated GAG mixtures were studied. Mean values of total GAG concentration, in terms of hexuronic acid, ranged from a maximum of about 12 mg/l in serum of calves, trained horses and sheep to about 9 mg/l in serum of cows and donkeys and in plasma of trained horses to about 6.5 mg/l in sedentary horse serum and rabbit plasma to a minimum of 4 mg/l in dog serum and sedentary horse plasma. Statistically significant differences in total GAG concentrations (P < 0.0005) were found in horses between plasma and serum and also between sedentary and trained subjects. Chondroitin sulphate was the main component in serum and plasma GAG mixtures, accounting for 81–84% of total GAGs in the examined animals, except in cow serum (72%), trained horse plasma (75.5%) and sheep serum (87%). Keratan sulphate-like structures, measured as galactose, ranged from 12% in sheep serum to 17% in cattle serum. Fucose was associated with galactose in GAG fractions, which supports the hypothesis that articular cartilage is among the sites of origin of circulating GAGs.     

Melanoma and subcutaneous adipose tissue: Role of peritumoral adipokines in disease characterization and prognosis

In the last decades, the concept of adipose organ has emerged, giving adipose tissue an active endocrine and immunologic function through the secretion of multiple cytokines and chemokines that seem to be implicated in the development and progression of several cancer, including cutaneous melanoma. In this pilot experimental study, we analyzed the expression in the peritumor subcutaneous adipose tissue of the most significant adipokines involved in the processes of carcinogenesis and metastasis in a population of melanoma patients and in two control groups composed of melanocytic nevi and epidermoid cysts, respectively. We correlated the results obtained with the main disease prognostic factors observing a statistically significant increase in the expression of PAI1, LEP, CXCL1, NAMPT, and TNF-α at the level of the peritumor tissue of the melanoma samples compared to the control groups and a correlation of the same with the histopathological prognostic factor of melanoma. Our preliminary study shows that the overexpression of PAI1, LEP, CXCL1, NAMPT, and TNF-α may contribute to the growth and to the local aggressiveness of cutaneous melanoma. It opens the hypothesis of a direct oncogenic role of subcutaneous adipose tissue and adipokines in the tumorigenesis of melanoma.     

BAZ2A safeguards genome architecture of ground‐state pluripotent stem cells

Chromosomes have an intrinsic tendency to segregate into compartments, forming long‐distance contacts between loci of similar chromatin states. How genome compartmentalization is regulated remains elusive. Here, comparison of mouse ground‐state embryonic stem cells (ESCs) characterized by open and active chromatin, and advanced serum ESCs with a more closed and repressed genome, reveals distinct regulation of their genome organization due to differential dependency on BAZ2A/TIP5, a component of the chromatin remodeling complex NoRC. On ESC chromatin, BAZ2A interacts with SNF2H, DNA topoisomerase 2A (TOP2A) and cohesin. BAZ2A associates with chromatin sub‐domains within the active A compartment, which intersect through long‐range contacts. We found that ground‐state chromatin selectively requires BAZ2A to limit the invasion of active domains into repressive compartments. BAZ2A depletion increases chromatin accessibility at B compartments. Furthermore, BAZ2A regulates H3K27me3 genome occupancy in a TOP2A‐dependent manner. Finally, ground‐state ESCs require BAZ2A for growth, differentiation, and correct expression of developmental genes. Our results uncover the propensity of open chromatin domains to invade repressive domains, which is counteracted by chromatin remodeling to establish genome partitioning and preserve cell identity.     

An attempt to discriminate catalytic and regulatory proton binding sites in membrane-bound, thiol-reduced chloroplast ATPase.

The question of the possible identity of catalytic and regulatory proton pathways in the chloroplast FoF1 ATPase has been studied using different energy-transfer inhibitors. Venturicidin, a reversible inhibitor of Fo, affects neither the delta mu H(+)-dependent thiol reduction of the membrane-bound chloroplast ATPase nor its ability to be activated by the proton gradient. It seems therefore to block only the proton flow required by the catalytic function of the enzymes. Venturicidin, however, also slows down the deactivation of the thiol-reduced ATPases during uncoupled ATP hydrolysis, following a delta mu H+ activation, but phloridzin, a reversible F1 inhibitor, has the same effect. Tentoxin, an irreversible F1 inhibitor, decreases the rate of ATP hydrolysis but does not affect the rate of deactivation. These findings suggest that catalytic and regulatory H(+)-binding sites are different. No distinction can be made, if any, between protons involved in unmasking the thiol-sensitive groups of F1 and in activating the enzyme. The effect of venturicidin and phloridzin on the deactivation is consistent with an inhibitory effect of newly formed--by ATP hydrolysis--ADP molecules, which might affect the enzyme without passing through the medium. Phosphate at millimolar concentration has an effect similar to low concentrations of phloridzin and venturicidin, probably by a simple back-reaction effect.     

Mapping and ultrastructure of antennal chemosensilla of the wheat bug Eurygaster maura

Antennae of the wheat stink bug Eurygaster maura L. (Hemiptera: Scutelleridae) were investigated to elucidate structure and distribution of antennal chemosensilla in females. Five type of sensilla were identified and characterized using a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Type 1 sensilla are mechanical and contact chemoreceptors with a single apical pore. Types 2 and 3 sensilla are multiporous chemoreceptors both with typical features of olfactory sensilla. Type 4 are multiporous peg-like sensilla, short and with a grooved surface. Type 5 are sensilla coeloconica with a smooth and aporous peg completely inserted in a sub-cuticular chamber. All types are distributed on the two flagellar segments, but we considered only the apical flagellomere in which the largest number of sensilla are located. The most abundant sensilla are type 3, while the less numerous are type 5. All types, except type 2, decreased in number from the tip to the base of the segment. The lower density of sensilla was recorded on the dorsal-internal part of the apical antennomere, while the higher density was recorded on the opposite side (external-ventral).     

Correlation between serum glutathione reductases and bone densitometry values]

Free radicals, because of their marked chemical activity, have often been found to be involved in many human diseases. Enzymatic antioxidant systems, namely glutathione-reductase, present both in red blood cells and in serum, have been demonstrated to play a key role as free radicals scavengers. The present work has been carried out in order to evaluate the possible role played by free radicals in the demineralization process of the bone matrix. Glutathione-reductase activity, assayed by a slightly modified Horn's method, was related to bone density measurements. All the subjects with reduced densitometric values showed reduced glutathione-reductase levels. Our results seem to support the hypothesis of a strict relationship between low activity of antioxidant systems and demineralization process of the bone, in consequence of enhanced free radical levels.     

The Johnston's organ of three homopteran species: A comparative ultrastructural study

A transmission electron-microscopy study has been carried out on the pedicel of three homopteran species, with particular focus on the leafhopper Scaphoideus titanus Ball. The two other species, the planthoppers Hyalesthes obsoletus Signoret and Metcalfa pruinosa Say, were investigated in order to compare the ultrastructure of the Johnston's organ (JO) among representatives of the Auchenorrhyncha group. The results showed the presence of a well developed JO located within the pedicel. Depending on the species the JO is made of 25 up to 72 scolopidia arranged in a coronal array. Each scolopidium is connective, heterodynal, amphinematic and hosts three structurally dissimilar sensory neurons. Two of them have a type 1 ciliary segment while the third bears a type 2 cilium. The type 2 dendrite tip is associated with a tubular cap and is longer than the others, ending into the cuticle at the base of the flagellum. Other scolopidia with one or two neurons were found in S. titanus, forming an accessory organ. The presence of such a well developed mechanosensory apparatus is discussed in relation with the lifestyle of the three species.