Entire genome of a strain of human immunodeficiency virus type 1 with a deletion of nef that was recovered 20 years after primary infection: large pool of proviruses with deletions of env

We report the complete sequence analysis of the provirus harbored in a long-term nonprogressor (patient SG1) 20 years after the first infection with a human immunodeficiency virus type 1 strain lacking nef. The sequencing showed large deletions in the nef-nef and nef-U3 regions. Except for vpu, all of the other accessory genes were intact. The gag and pol genes did not show significant alterations. We found large deletions in env, spanning the V1, V2, V3, V4, and V5 regions. We believe that, when down-regulation of the class 1 major histocompatibility complex molecules is inhibited by the lack of nef function, the cells containing Env-defective molecules evade cytotoxic T lymphocyte killing and accumulate progressively.     

Involvement of adenosine A1 and A2A receptors in (-)-linalool-induced antinociception

In recent studies performed in our laboratory we have shown that acute administration of (-)-linalool, the natural occurring enantiomer in essential oils, possesses anti-inflammatory, antihyperalgesic and antinociceptive effects in different animal models. The antihyperalgesic and antinociceptive effects of (-)-linalool have been ascribed to its capacity in stimulating the opioidergic, cholinergic and dopaminergic systems, as well as to its interaction with K+ channels, or to its local anaesthetic activity and/or to the negative modulation of glutamate transmission. Activation of A1 or A2A receptors has been shown to induce antinociceptive effects, and the possible involvement of adenosine in (-)-linalool antinociceptive effect, has not been elucidated yet. Therefore, in the present study, we have investigated the effects of 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), a selective adenosine A1 receptor antagonist and the effects of 3,7-dimethyl-1-propargilxanthine (DMPX), a selective adenosine A2A receptor antagonist on the antinociception of (-)-linalool in mice, measured in the hot-plate test. Both DPCPX (0.1 mg/kg; i.p.) and DMPX (0.1 mg/kg; i.p.) pre-treatment significantly depressed the antinociceptive effect of (-)-linalool at the highest doses tested. These findings demonstrated that the effect of (-)-linalool on pain responses is, at least partially, mediated by the activity of adenosine A1 and A2A receptors.     

Cloricromene effect on the enzyme activities of the tryptophan-nicotinic acid pathway in diabetic/hyperlipidemic rabbits

Since alterations of tryptophan metabolism have been reported in diabetes and atherosclerosis, it was thought of interest to investigate any role of cloricromene through the influence on the oxidative metabolism of the amino acid by using diabetic/hyperlipidemic rabbits.Male 4-month-old New Zealand white rabbits, fed a diet enriched with 1% cholesterol and 10% corn oil, were made diabetic with alloxan. During the hyperlipidemic diet, a group of rabbits was treated with cloricromene (10 mg/kg/day subcutaneously plus 1.5 mg/kg/day intravenously, for 5 weeks). The other group received saline. Normometabolic New Zealand rabbits fed standard diet, treated or not with cloricromene, were used as control.The specific activities of liver tryptophan 2,3-dioxygenase and small intestine indole 2,3-dioxygenase were not significantly changed by the drug treatment. Also the specific activities of other enzymes of the kynurenine pathway in the liver and kidneys, specifically kynurenine 3-monooxygenase, kynureninase and kynurenine-oxoglutarate transaminase, did not show any significant difference in both tissues between the two groups of rabbits. On the contrary, 3-hydroxyanthranilate 3,4-dioxygenase activity in the liver of diabetic/hyperlipidemic rabbits and control rabbits treated with cloricromene showed a slight increase in comparison with untreated animals. Conversely, the specific activity of the enzyme in kidneys was not affected by the drug treatment in diabetic/hyperlipidemic animals but was reduced in controls. Aminocarboxymuconate-semialdehyde decarboxylase specific activity remained unchanged in the liver following cloricromene treatment, instead the specific activity of the enzyme in the kidneys of the diabetic/hyperlipidemic rabbits was significantly increased by the drug, with a value more than double in comparison to untreated animals. The activity of the scavenger enzyme Cu/Zn superoxide dismutase (Cu/Zn SOD) in the small intestine was also determined and found significantly increased of about twice as much in the group of diabetic/hyperlipidemic rabbits treated with cloricromene.In conclusion, in diabetic/hyperlipidemic rabbits, cloricromene appeared to influence the enzymes involved in the last steps of tryptophan oxidative metabolism through the kynurenine pathway. This, together with the antioxidant action through the activation of Cu/Zn SOD, might deserve further investigation for evaluating any link between the observed experimental findings at the level of the kynurenine pathway and the clinical effect of the drug.     

Reduced spontaneous relaxation in immature guinea pig airway smooth muscle is associated with increased prostanoid release

Airway smooth muscle (ASM) from infant guinea pigs has less spontaneous relaxation during stimulation than ASM from adults. Inhibition of cyclooxygenase (COX), which catalyzes the production of prostanoids, increases this relaxation in infant ASM and abolishes age differences, thus suggesting that prostanoids reduce relaxation in infant ASM. In this study, we investigated whether leukotrienes are also involved in reducing spontaneous relaxation; whether the two COX isoforms, COX-1 and COX-2, differentially regulate spontaneous relaxation; and whether prostanoid release is developmentally regulated in guinea pig ASM. In different age groups, we measured relaxation during and after electrical stimulation in tracheal strips as well as prostanoid release from tracheal segments. Relaxation was studied in the absence and in the presence of a lipoxygenase inhibitor, a cysteinyl leukotriene receptor-1 antagonist, a COX-1 inhibitor, or a COX-2 inhibitor. We found that inhibition of lipoxygenase or cysteinyl leukotriene receptor-1 antagonism did not increase spontaneous relaxation at any age, thus excluding a role for leukotrienes in this phenomenon. Inhibition of COX-2, but not COX-1, promoted spontaneous relaxation. The basal release of prostanoids was more abundant in tissue from infant animals and decreased significantly with age. Thromboxane B2 was the most abundant metabolite released at all ages. Electrical stimulation and epithelium removal did not affect the age difference in prostanoid release. We conclude that increased basal prostanoid release contributes to the reduced spontaneous relaxation in immature guinea pig ASM compared with older animals. By regulating ASM relaxation, prostanoids may play a role in the airway hyperresponsiveness at a young age.     

Targeting the X-linked inhibitor of apoptosis protein through 4-substituted azabicyclo[5.3.0]alkane smac mimetics. Structure, activity, and recognition principles

The X-linked inhibitor of apoptosis protein (XIAP) is overexpressed in several malignant cells where it prevents apoptosis by binding to, and blocking, the activation of caspase-3, -7, and -9. Human XIAP (479 residues) is composed of three tandem-repeated baculoviral IAP repeat (BIR) domains (BIR1-3), and by a C-terminal RING domain. Smac-DIABLO [second mitochondria-derived activator of caspases (Smac)-direct IAP binding protein with low pI (DIABLO)], the natural antagonist of XIAP, binds through its N-terminal sequence AVPI to the same surface groove, in the BIR domains, that binds caspases. Synthetic compounds mimicking such tetrapeptide motif effectively block the interaction between IAP and active caspases, thus triggering apoptosis. Peptidomimetics based on an azabicyclo[x.y.0]alkane scaffolds, have been shown to bind the BIR3 domain of XIAP with micromolar to nanomolar affinities, thus presenting attractive features for drug lead optimization. Here we report a study on three newly synthesized Smac mimetics, which have been characterized in their complexes with XIAP BIR3 domain through X-ray crystallography and molecular modelling/docking simulations. Based on analysis of the crystal structures, we show that specific substitutions at the 4-position of the azabicyclo[5.3.0]alkane scaffold results in sizeable effects on the peptidomimetic-BIR3 domain affinity. By means of functional, biophysical and simulative approaches we also propose that the same Smac mimetics can bind XIAP BIR2 domain at a location structurally related to the BIR3 domain AVPI binding groove. Details of the XIAP-Smac mimetic recognition principles highlighted by this study are discussed in light of the drug-like profile of the three (potentially proapoptotic) compounds developed that show improved performance in ADMET (adsorption, distribution, metabolism, excretion and toxicity) tests.     

Physical and functional interaction between the Bloom's syndrome gene product and the largest subunit of chromatin assembly factor 1

Bloom's syndrome (BS) is a genomic instability disorder characterized by cancer susceptibility. The protein defective in BS, BLM, belongs to the RecQ family of DNA helicases. In this study, we found that BLM interacts with hp150, the largest subunit of chromatin assembly factor 1 (CAF-1), in vitro and in vivo. Colocalization of a proportion of the cellular complement of these two proteins is found at specific nuclear foci coinciding with sites of DNA synthesis in the S phase. This colocalization increases in the presence of agents that damage DNA or inhibit DNA replication. In support of a functional interaction between BLM and CAF-1, we show that BLM inhibits CAF-1-mediated chromatin assembly during DNA repair in vitro. Although CAF-1 activity is not altered in BLM-deficient cells, the absence of BLM does impair the ability of CAF-1 to be mobilized within the nucleus in response to hydroxyurea treatment. Our results provide the first link between BLM and chromatin assembly coupled to DNA repair and suggest that BLM and CAF-1 function in a coordinated way to promote survival in response to DNA damage and/or replication blockade.     

Impact of two fluorescent pseudomonads and an arbuscular mycorrhizal fungus on tomato plant growth,root architecture and P acquisition

The ability of fluorescent pseudomonads and arbuscular mycorrhizal fungi (AMF) to promote plant growth is well documented but knowledge of the impact of pseudomonad-mycorrhiza mixed inocula on root architecture is scanty. In the present work, growth and root architecture of tomato plants (Lycopersicon esculentum Mill. cv. Guadalete), inoculated or not with Pseudomonas fluorescens 92rk and P190r and/or the AMF Glomus mosseae BEG12, were evaluated by measuring shoot and root fresh weight and by analysing morphometric parameters of the root system. The influence of the microorganisms on phosphorus (P) acquisition was assayed as total P accumulated in leaves of plants inoculated or not with the three microorganisms. The two bacterial strains and the AMF, alone or in combination, promoted plant growth. P. fluorescens 92rk and G. mosseae BEG12 when co-inoculated had a synergistic effect on root fresh weight. Moreover, co-inoculation of the three microorganisms synergistically increased plant growth compared with singly inoculated plants. Both the fluorescent pseudomonads and the myco-symbiont, depending on the inoculum combination, strongly affected root architecture. P. fluorescens 92rk increased mycorrhizal colonization, suggesting that this strain is a mycorrhization helper bacterium. Finally, the bacterial strains and the AMF, alone or in combination, improved plant mineral nutrition by increasing leaf P content. These results support the potential use of fluorescent pseudomonads and AMF as mixed inoculants for tomato and suggest that improved tomato growth could be related to the increase in P acquisition.     

The mesolimbic dopaminergic response to novel palatable food consumption increases dopamine-D1 receptor-mediated signalling with complex modifications of the DARPP-32 phosphorylation pattern

Acute cocaine administration increases extraneuronal dopamine and Thr34 phosphorylation of dopamine- and cAMP-regulated phosphoprotein (M(r) 32 kDa; DARPP-32) in striatal and cortical areas. Novel palatable food consumption increases extraneuronal dopamine in the same areas. We examined the DARPP-32 phosphorylation pattern in food non-deprived rats at different times after vanilla sugar consumption. The phosphorylation state of DARPP-32 and two cAMP-dependent protein kinase (PKA) substrates, GluR1 and NR1, were detected by immunoblotting. Thirty to 45 min after vanilla sugar consumption, phospho-Thr34 DARPP-32, GluR1 and NR1 levels increased in the nucleus accumbens, and phospho-Thr75 DARPP-32 levels decreased. At 60 min, all parameters returned to baseline values. However, 2 and 3 h after vanilla sugar consumption, phospho-Thr34 DARPP-32 levels decreased, while phospho-Thr75 DARPP-32 levels increased. In contrast to the pattern observed in the NAcS, no delayed changes in DARPP-32 phosphorylation were observed in the mPFC. Both early and delayed DARPP-32, GluR1 and NR1 phosphorylation changes were prevented by a dopamine D1 receptor antagonist administration. The delayed modifications in nucleus accumbens DARPP-32 phosphorylation were prevented by an mGluR5 antagonist administration. The mesolimbic dopaminergic response to an unfamiliar taste is correlated to a gustatory memory trace development, and the observed changes in DARPP-32 phosphorylation may be part of this process.     

Influence of age on Cu/Zn-superoxide dismutase and indole 2,3-dioxygenase activities in rat tissues

The aim of this study was to investigate in vitro the variations with age of the activities of the two antioxidant enzymes Cu/Zn-superoxide dismutase (SOD) and indole 2,3-dioxygenase (IDO) in metabolically active tissues of rats of various ages. In rats aged one week and 2-3 months the highest Cu/Zn-SOD activity was found in the liver and the lowest in the small intestine. At 12 and 18 months of age, the activity was higher in the brain and kidneys, when compared to the small intestine, lungs and liver. Cu/Zn-SOD activity decreased significantly after 2-3 months of age with advancing age in all tissues examined. In newborn rats IDO activity was present only in the small intestine. In the group of rats aged 2-3 months, the highest specific activity was observed in the small intestine and the lowest in the lungs and kidneys, whereas at 12 months of age, the highest IDO activity was found in the brain, with kidneys presenting the lowest activity. At 18 months, IDO returned to be more elevated in the small intestine. At 12 months of age the values of IDO in the tissues varied slightly, while at 18 months similar activities were found between the lungs and brain and between the small intestine and kidneys. In relation to age, IDO specific activity declined in the small intestine, after 2-3 months of age. In the lungs, the activity remained unchanged; in the brain and in the kidneys activity decreased significantly from 2-3 to 18 months of age. In conclusion, this study demonstrates an age-related decline in Cu/Zn-SOD and IDO activities, the two enzymes responsible for scavenging O2*-.