Ubiquitin-protein ligase Ubr5 cooperates with hedgehog signalling to promote skeletal tissue homeostasis

Mammalian Hedgehog (HH) signalling pathway plays an essential role in tissue homeostasis and its deregulation is linked to rheumatological disorders. UBR5 is the mammalian homologue of the E3 ubiquitin-protein ligase Hyd, a negative regulator of the Hh-pathway in Drosophila. To investigate a possible role of UBR5 in regulation of the musculoskeletal system through modulation of mammalian HH signaling, we created a mouse model for specific loss of Ubr5 function in limb bud mesenchyme. Our findings revealed a role for UBR5 in maintaining cartilage homeostasis and suppressing metaplasia. Ubr5 loss of function resulted in progressive and dramatic articular cartilage degradation, enlarged, abnormally shaped sesamoid bones and extensive heterotopic tissue metaplasia linked to calcification of tendons and ossification of synovium. Genetic suppression of smoothened (Smo), a key mediator of HH signalling, dramatically enhanced the Ubr5 mutant phenotype. Analysis of HH signalling in both mouse and cell model systems revealed that loss of Ubr5 stimulated canonical HH-signalling while also increasing PKA activity. In addition, human osteoarthritic samples revealed similar correlations between UBR5 expression, canonical HH signalling and PKA activity markers. Our studies identified a crucial function for the Ubr5 gene in the maintenance of skeletal tissue homeostasis and an unexpected mode of regulation of the HH signalling pathway.     

Evaluation of the effect of cloxacillin on human lymphocyte chromosomes through the study of karyotypic changes and sister chromatid exchanges

The aim of this work was the evaluation of the possible mutagenic effect of an antibiotic, the Cloxacillin. Therefore the authors have performed the analysis of the chromosomal alterations and the study of the SCE (Sister Chromatid Exchanges) induced with the exposition of cultures of lymphocytes to different concentrations of this drug. The work reveals that Cloxacillin induces chromosomal alterations at high concentrations, while at concentrations similar to its therapeutic levels the drug does not seem to interfere with human DNA.     

Effect of vanadate and pyridoxal phosphate on S-adenosylmethionine

Vanadate in the presence of pyridoxal phosphate promotes the decarboxylation of S-adenosylmethionine. Pyridoxal has a lower effect; pyridoxine none. The rate of decarboxylation depends on pyridoxal phosphate and vanadate concentration. Vanadate as low as 10(-7) M gives significant decarboxylation. The reaction seems to occur through the formation of a Schiff base. The spectral shift elicited by S-adenosylmethionine on pyridoxal phosphate due to the presence of the sulfonium function is influenced by vanadate. Orthovanadate is a little less effective then metavanadate; vanadyl sulfate is even less efficient, and the effect of Cu2+ at the same concentration is still lower. Bleomycin partially prevents the vanadium effect. In vivo, vanadate promotes a marked increase in chicken liver S-adenosylmethionine and S-adenosylhomocysteine concentration, whereas the polyamine concentration is unaffected.     

Neurotransmitter control of pupillary motoricity in man

The pupillary responses to different agonists and antagonists of the sympathetic and parasympathetic systems have been studied in normal volunteers. The eyedrops were instilled unilaterally and the responses were evaluated by measuring the changes in diameter of the pupils (in millimeters). All the eyedrops induced an unilateral response on the instilled side. The mydriatic substances (phenylephrine, thropamide, tyramine) showed an evident and lasting action. Phenylephrine 1% was found to be a threshold dose to acquire the mydriatic effect. The beta blocking agent (timolol) induced a short mydriatic response, while methaproterenol did not change the pupillary diameter. Clonidine caused an unilateral mydriasis. The alpha blocking agent and the parasympathetic system stimulation agent induced miotic effects The results are discussed with particular reference to the possible mechanism of the pupillary response to timolol and clonidine.     

Regulation of spermidine acetyltransferase activity by phosphorylation and dephosphorylation

Spermidine acetyltransferase activity is more than 10-fold higher in the pancreas of a 20-hr-fasted than in that of a fed chicken. The preparation of the fed bird inactivates the other. The effect is due to a thermolabile component of microsomes, and is also obtained with alkaline phosphatase. The inactivated preparation partially recovers its activity through phosphorylation catalyzed by a cAMP-dependent protein kinase. The results presented strongly suggest that spermidine acetyltransferase activity is regulated by phosphorylation and dephosphorylation.     

Seed image analysis provides evidence of taxonomical differentiation within the Lavatera triloba aggregate (Malvaceae)

Thirty-four seed morphometric and colorimetric features of the five taxa belonging to the Lavatera triloba aggregate were measured using an image analysis system. Data were statistically analysed using a Linear Discriminant Analysis (LDA), which provided evidence to reassess the taxonomic position of some neglected or doubtful taxa. The results confirm the differentiation of the insular endemics L. agrigentina, L. triloba ssp. pallescens and L. triloba ssp. minoricensis. Moreover, the Sardinian populations of L. triloba ssp. triloba are clearly differentiated from their Iberian counterparts, but on the other hand, the seed morpho-colorimetric variation between L. triloba ssp. triloba and L. flava is not easy to interpret.     

Chemical composition and antimicrobial activity of cuticular and internal lipids of the insect Rhynchophorus palmarum

Insect cuticle lipids are involved in various types of chemical communication between species, and reduce the penetration of insecticides, chemicals, and toxins, as well as provide protection against the attack of microorganisms, parasitic insects, and predators. Ecological studies related to the insect Rhynchophorus palmarum are well-known; however, very little is known about its resistance mechanisms, which includes its lipid composition and its importance, specifically the cuticle layer. This study aimed to characterize the cuticle and internal lipid compounds of the male and female R. palmarum adult insects and to evaluate the presence of antimicrobial activity. We performed by gas chromatography coupled to mass spectrometry (GC–MS) analyzes of lipid extracts fractions and we identified 10 methyl esters of fatty acids esters of C14 to C23, with variation between the sexes of C22:0, C21:0, present only in male cuticle, and C20:2 in female. The lipid content of this insect showed relevant amount of C16:1, C18:1, and C18:2. The antimicrobial activity of the cuticular and internal fractions obtained was tested, which resulted in minimum inhibitory concentrations between 12.5 and 20 μg/ml against Gram-positive bacteria (Staphylococcus epidermidis, Enterococcus faecalis), Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia), and fungal species (Candida albicans e Candida tropicalis). The antimicrobial effect of the R. palmarum cuticle open perspectives for a new source to bioinsecticidal strategies, in addition to elucidating a bioactive mixture against bacteria and fungi.