Characterization of a metal resistant Pseudomonas sp. isolated from uranium mine for its potential in heavy metal (Ni2+, Co2+, Cu2+, and Cd2+) sequestration

Heavy metal sequestration by a multimetal resistant Pseudomonas strain isolated from a uranium mine was characterized for its potential application in metal bioremediation. 16S rRNA gene analysis revealed phylogenetic relatedness of this isolate to Pseudomonas fluorescens. Metal uptake by this bacterium was monophasic, fast saturating, concentration and pH dependent with maximum loading of 1048 nmol Ni²⁺ followed by 845 nmol Co²⁺, 828 nmol Cu²⁺ and 700 nmol Cd²⁺ mg^?1 dry wt. Preferential metal deposition in cell envelope was confirmed by TEM and cell fractionation. FTIR spectroscopy and EDX analysis revealed a major role of carboxyl and phosphoryl groups along with a possible ion exchange mechanism in cation binding. Binary system demonstrated selective metal binding affinity in the order of Cu²⁺ > Ni²⁺ > Co²⁺ > Cd²⁺. A comparison with similar metal uptake reports considering live bacteria strongly indicated the superiority of this strain in metal sequestration, which could be useful for developing efficient metal removal system.     

Synthesis of bis-Schiff bases of isatins and their antiglycation activity

Bis-Schiff bases 1–27 have been synthesized and their in vitro antiglycation potential has been evaluated. Compounds 21 (IC₅₀ = 243.95 ± 4.59 μM), 20 (IC₅₀ = 257.61 ± 5.63 μM), and 7 (IC₅₀ = 291.14 ± 2.53 μM) showed an excellent antiglycation activity better than the standard (rutin, IC₅₀ = 294.46 ± 1.50 μM). This study has identified a series of potential molecules as antiglycation agents. A structure–activity relationship has been studied, and all the compounds were characterized by spectroscopic techniques.     

Unsymmetrically disubstituted urea derivatives: A potent class of antiglycating agents

A series of unsymmetrically disubstituted urea derivatives 1–28 has been synthesized and screened for their antiglycation activity in vitro. Compounds 26 (IC₅₀ = 4.26 ± 0.25 μM), 1 (IC₅₀ = 5.8 ± 0.08 μM), 22 (IC₅₀ = 4.26 ± 0.25 μM), 6 (IC₅₀ = 6.4 ± 0.02 μM), 5 (IC₅₀ = 6.6 ± 0.26 μM), 2 (IC₅₀ = 7.02 ± 0.31 μM), 3 (IC₅₀ = 7.14 ± 0.84 μM), 27 (IC₅₀ = 7.27 ± 0.36 μM), 4 (IC₅₀ = 8.16 ± 1.04 μM), 21 (IC₅₀ = 8.4 ± 0.15 μM), 23 (IC₅₀ = 9.0 ± 0.35 μM) and 13 (IC₅₀ = 15.22 ± 6.7 μM) showed an excellent antiglycation activity far better than the standard (rutin, IC₅₀ = 41.9 ± 2.3 μM). This study thus provides a series of potential molecules for further studies of antiglycation agents.     

Population ecology of yew (<Emphasis Type="Italic">Taxus baccata</Emphasis> L.) in the Central Apennines: spatial patterns and their relevance for conservation strategies

Understanding the ecological mechanisms that allow a species to transition from an occasional understory component to the dominant type in the forest canopy is essential for predicting future shifts in the distribution of species. We investigated this issue with regard to yew, also because mature yew trees have been reported to inhibit self-regeneration and seedling survival, prompting concerns for the long-term preservation of the species. Our objectives were (a) to quantify spatial patterns of yew (Taxus baccata L.) populations near the southern limit of the species’ ecological distribution, (b) to determine the relationships between yew presence and topographic gradients, and (c) to answer the question of how yew regeneration is affected by such patterns and relationships. We analyzed three extensive yew populations (90–165 ha, including 3–12 thousand established individuals) that mostly occupy the understory of beech forests located in protected areas of the central Apennines (Italy). Overall, the realized niche of yew (either as established trees, saplings, or seedlings) followed the expected bell-shaped curve of a species response to an environmental gradient. Yew was mainly found at 1,000–1,600 m elevation on mesic exposures (north and west) and intermediate slopes (30–60%). Geostatistical analysis revealed that yew occurred in patches, as shown by variogram ranges of 40–110 m for yew tree basal area and regeneration abundance. Yew regeneration over the landscape was directly related to basal area of yew trees. At local scales (~10 m), presence of established trees favored regeneration in relatively less developed stands, whereas high density of mature yews suppressed regeneration. Healthy yew populations in beech forests had a minimum size of 0.5–3 ha. As yew density increased within these patches, regeneration dropped, so that yew conservation cannot be limited to presently occurring populations, despite the longevity and potential for vegetative reproduction of the species. Disturbance from grazing and wildfire was also found to impact yew survival. Long-term existence of yew in the Italian Apennines depends on maintaining and expanding old-growth beech forests that incorporate yew patches, and have a minimum continuous cover equivalent to a relatively undisturbed regime (10–50 ha).     

Protein glycation inhibitory activities of Lawsonia inermis and its active principles

The protein glycation inhibitory activity of ethanolic extract of Lawsonia inermis (henna) plant tissues was evaluated in vitro using the model system of bovine serum albumin and glucose. Protein oxidation and glycation are posttranslational modifications that are implicated in the pathological development of many age-related disease processes. This study investigated the effects of Lawsonia inermis ethanolic extract and its components, on protein damage induced by a free radical generator in in vitro assay system. We found that alcoholic extract of Lawsonia inermis can effectively protect against protein damage and showed that its action is mainly due to Lawsone. In addition, the presence of gallic acid also plays an important role in the protective activity against protein oxidation and glycation. Two known compounds, namely, Lawsone and gallic acid previously isolated from this plant were subjected to glycation bioassay for the first time. It was found that the alcoholic extract, lawsone (1) and gallic acid (2) showed significant inhibition of Advanced Glycated End Products (AGEs) formation and exhibit 77.95%, 79.10% and 66.98% inhibition at a concentration of 1500 microg/mL, 1000 microg/mL and 1000 microM respectively. Lawsonia inermis, compounds 1 and 2 were found to be glycation inhibitors with IC(50) 82.06 +/- 0.13 microg/mL, 67.42 +/- 1.46 microM and 401.7 +/- 6. 23 microM respectively. This is the first report on the glycation activity of these compounds and alcoholic extract of Lawsonia inermis.     

Absence of TGFβ signaling in embryonic vascular smooth muscle leads to reduced lysyl oxidase expression,impaired elastogenesis,and aneurysm

To address the requirement for TGFβ signaling in the formation and maintenance of the vascular matrix, we employed lineage‐specific mutation of the type II TGFβ receptor gene (Tgfbr2) in vascular smooth muscle precursors in mice. In both neural crest‐ and mesoderm‐derived smooth muscle, absence of TGFβ receptor function resulted in a poorly organized vascular elastic matrix in late‐stage embryos which was prone to dilation and aneurysm. This defect represents a failure to initiate formation of the elastic matrix, rather than a failure to maintain a preexisting matrix. In mutant tissue, lysyl oxidase expression was substantially reduced, which may contribute to the observed pathology. genesis 47:115–121, 2009. © 2009 Wiley‐Liss, Inc.     

Privileged structure based ligands for melanocortin receptors--4,4-disubstituted piperidine derivatives

Homologation and cyclization back to the chiral methine of compound 3 yields achiral 4,4-disubstituted piperidine privileged structures (e.g., 8a) useful in the construction of melanocortin 4 receptor (MC4R) ligands. The piperidine nitrogen was replaced with carbon, oxygen, sulfur, and sulfone with minor erosion of binding. The methyl cyclohexane substituent was the most potent while significant affinity was still seen for smaller lipophilic groups such as ethyl.     

Synthesis and radiosynthesis of [(18)F]FPhEP, a novel alpha(4)beta(2)-selective, epibatidine-based antagonist for PET imaging of nicotinic acetylcholine receptors

FPhEP (1, (+/-)-2-exo-(2'-fluoro-3'-phenyl-pyridin-5'-yl)-7-azabicyclo[2.2.1]heptane) belongs to a recently described novel series of 3'-phenyl analogues of epibatidine, which not only possess subnanomolar affinity and high selectivity for brain alpha4beta2 neuronal nicotinic acetylcholine receptors (nAChRs), but also were reported as functional antagonists of low toxicity (up to 15 mg/kg in mice). FPhEP (1, K(i) of 0.24 nM against [(3)H]epibatidine) as reference as well as the corresponding N-Boc-protected chloro- and bromo derivatives (3a,b) as precursors for labelling with fluorine-18 were synthesized in eight and nine steps, respectively, from commercially available N-Boc-pyrrole (overall yields=17% for 1, 9% for 3a and 8% for 3b). FPhEP (1) was labelled with fluorine-18 using the following two-step radiochemical process: (1) no-carrier-added nucleophilic heteroaromatic ortho-radiofluorination from the corresponding N-Boc-protected chloro- or bromo derivatives (3 a,b-1mg) and the activated K[(18)F]F-Kryptofix(222) complex in DMSO using microwave activation at 250 W for 1.5 min, followed by (2) quantitative TFA-induced removal of the N-Boc-protective group. Radiochemically pure (>99%) [(18)F]FPhEP ([(18)F]-1, 2.22-3.33 GBq, 66-137 GBq/micromol) was obtained after semi-preparative HPLC (Symmetry C18, eluent aq 0.05 M NaH(2)PO(4)/CH(3)CN, 80:20 (v:v)) in 75-80 min starting from a 18.5 GBq aliquot of a cyclotron-produced [(18)F]fluoride production batch (10-20% nondecay-corrected overall yield). In vitro binding studies on rat whole-brain membranes demonstrated a subnanomolar affinity (K(D) 660 pM) of [(18)F]FPhEP ([(18)F]-1) for nAChRs. In vitro autoradiographic studies also showed a good contrast between nAChR-rich and -poor regions with a low non-specific binding. Comparison of in vivo Positron Emission Tomography (PET) kinetics of [(18)F]FPhEP ([(18)F]-1) and [(18)F]F-A-85380 in baboons demonstrated faster brain kinetics of the former compound (with a peak uptake at 20 min post injection only). Taken together, the preliminary data obtained confirm that [(18)F]FPhEP ([(18)F]-1) has potential for in vivo imaging nAChRs in the brain with PET.     

Synthesis, radiosynthesis and in vivo preliminary evaluation of [11C]LBT-999, a selective radioligand for the visualisation of the dopamine transporter with PET

LBT-999 (8-((E)-4-fluoro-but-2-enyl)-3beta-p-tolyl-8-aza-bicyclo[3.2.1]octane-2beta-carboxylic acid methyl ester), a cocaine derivative belonging to a new generation of highly selective dopamine transporter (DAT) ligands, and its corresponding carboxylic acid derivative, the latter used as precursor for labelling both with tritium and the positron-emitter carbon-11 (half-life: 20.38 min), were synthesized from (R)-cocaine. [(3)H]LBT-999 (>99% radiochemically pure, specific radioactivity of 3.1 TBq/mmol) was prepared from [(3)H]methyl iodide, allowing its in vitro pharmacological evaluation (K(D): 9 nM for DAT and IC(50) > 1000 nM for SERT and NET). Routine production batches of 4.5-9.0 GBq of iv injectable solutions of [(11)C]LBT-999 (with specific radioactivities ranging from 30 to 45 GBq/mumol) were prepared in 25-30 min (HPLC purification and formulation included) using the efficient methylation reagent [(11)C]methyl triflate. The preliminary in vivo pharmacological evaluation of [(11)C]LBT-999, using both biodistributions in rats and brain imaging in monkeys with positron emission tomography (PET), clearly illustrates that this ligand is an excellent candidate for quantification with PET of DAT in humans.