Semisynthesis of a Bacterium with Non-canonical Cell-Wall Cross-Links.

The cell wall is an elaborate framework of peptidoglycan that serves to protect the bacterium against osmotic challenge. This exoskeleton is composed of repeating saccharides covalently cross-linked by peptide stems. The general structure of the cell wall is widely conserved across diverse Gram-negative bacteria. To begin to explore the biological consequence of introducing non-canonical cross-links into the cell wall of Escherichia coli, we generated a bacterium where up to 31% of the cell-wall cross-links are formed by a non-enzymatic reaction between a sulfonyl fluoride and an amino group. Bacteria with these non-canonical cell-wall cross-links achieve a high optical density in culture, divide and elongate successfully, and display no loss of outer membrane integrity. This work represents a first step in the design of bacteria with non-canonical "synthetic" cell walls.

Design, Synthesis, and Mechanism Study of Benzenesulfonamide-Containing Phenylalanine Derivatives as Novel HIV-1 Capsid Inhibitors with Improved Antiviral Activities.

The HIV-1 CA protein has gained remarkable attention as a promising therapeutic target for the development of new antivirals, due to its pivotal roles in HIV-1 replication (structural and regulatory). Herein, we report the design and synthesis of three series of benzenesulfonamide-containing phenylalanine derivatives obtained by further structural modifications of PF-74 to aid in the discovery of more potent and drug-like HIV-1 CA inhibitors. Structure-activity relationship studies of these compounds led to the identification of new phenylalanine derivatives with a piperazinone moiety, represented by compound 11l, which exhibited anti-HIV-1NL4-3 activity 5.78-fold better than PF-74. Interestingly, 11l also showed anti-HIV-2ROD activity (EC50 = 31 nM), with almost 120 times increased potency over PF-74. However, due to the higher significance of HIV-1 as compared to HIV-2 for the human population, this manuscript focuses on the mechanism of action of our compounds in the context of HIV-1. SPR studies on representative compounds confirmed CA as the binding target. The action stage determination assay demonstrated that these inhibitors exhibited antiviral activities with a dual-stage inhibition profile. The early-stage inhibitory activity of compound 11l was 6.25 times more potent as compared to PF-74 but appeared to work via the accelerating capsid core assembly rather than stabilization. However, the mechanism by which they exert their antiviral activity in the late stage appears to be the same as PF-74 with less infectious HIV-1 virions produced in their presence, as judged p24 content studies. MD simulations provided the key rationale for the promising antiviral potency of 11l. Additionally, 11l exhibited a modest increase in HLM and human plasma metabolic stabilities as compared to PF-74, as well as a moderately improved pharmacokinetic profile, favorable oral bioavailability, and no acute toxicity. These studies provide insights and serve as a starting point for subsequent medicinal chemistry efforts in optimizing these promising HIV inhibitors.

Toxicity profiling of 24 l-phenylalanine derived ionic liquids based on pyridinium, imidazolium and cholinium cations and varying alkyl chains using rapid screening Vibrio fischeri bioassay.

A library of 24 pyridinium-, imidazolium-, and cholinium-based ionic liquids (ILs) with varying alkyl chain from C2 to C16 was toxicologically profiled using naturally luminescent marine bacteria Vibrio fischeri. The toxicity (30-min EC50) of studied ILs to Vibrio fischeri ranged from 7.82 µM (4.2 mg/L) (PyC12Phe) to 3096 µM (1227 mg/L) (ImidC2Phe), i.e. from "toxic" (EC50 1-10 mg/L) to "not harmful" (EC50 > 100 mg/L). Inhibition of the bacterial luminescence upon 30-min exposure to ILs correlated well with bacterial viability (exposure for 4 h). The toxicity of studied ILs was largely driven by the length of the alkyl chain (hydrophobicity) and not the type of cationic part of the IL: starting from C10 all the ILs irrespective of the cationic part proved "toxic". The toxicity of the studied ILs was increasing in parallel to their hydrophobicity up to log Kow = 1 (C8-C10) and then levelling up, being consistent with the previously obtained analogous data sets. The "cut-off" effect reported in this study for longer chain length members of the ILs series leads to the "limit" toxicity level for this type of ILs to be ca. 8 mM. Two open-access online tools (www.molinspiration.com and www.vcclab.org) have been applied for the calculation of the Kow values for the 24 ILs reported in this study and 21 ILs reported in the literature. This lead to plotting two nonlinear monotonic correlations between the values of experimental log (1/EC50) and calculated log Kow. The limitation of the online tools and an effect of the ILs structure on the "cut-off" effect have been discussed. The challenge of developing low microbial toxicity surface active ILs remains a significant task to overcome. Our results shed light on the new approaches for designing environmentally benign ILs and functional surfactants. As the hydrophobicity of the ILs significantly correlated with the toxicity, the Vibrio fischeri assay could be considered a powerful tool in providing toxicity data for building and evaluating the QSAR toxicity models for ILs.

Phenyl alanine & Tyrosine Amino acids Coated Magnetic Nanoparticles: Preparation and Toxicity study.

In this study we reported the synthesis of L-phenyl alanine (Phe) & L-tyrosine (Tyr) Natural Amino acids coated iron oxide magnetic nanoparticles under one-pot and in situ reaction. Functionalized iron oxide magnetic nanoparticles were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Vibrating Sample Magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) techniques. Cellular toxicity of amino acids coated iron oxide magnetic nanoparticles was also investigated on HEK-293 cell lines. Additionally, a hemolysis test of as prepared magnetic nanoparticles were performed. It was found that the synthesized Phe and Tyr coated magnetic nanoparticles (F@Phe NPs and F@Tyr NPs) were spherical in shape with an average size less than 25 nm, also the saturation magnetization (Ms) of the F@Phe NPs and F@Tyr NPs were about 30.02 and 58.23 emu/g, respectively, which was lower than those of bare Fe3O4. The TGA results show that apart from this weight loss, the coated sample shows a weight loss of 5.48, and 6.88% respectively corresponding to loss of Tyr, and Phe which is coated on the Fe3O4 nanoparticles. At a high concentration, less than 2.92 and 3.13% hemolytic activity were observed for F@Phe NPs and F@Tyr NPs, respectively. The F@Phe NPs and F@Tyr NPs show the possibility of using this nanoparticles in the development of in vitro and in vivo pharmaceutical and biomedical fields due to do not possess a toxic effect, good ζ-potential and related small and narrow size distribution.

Development of Novel Peptide-Based Michael Acceptors Targeting Rhodesain and Falcipain-2 for the Treatment of Neglected Tropical Diseases (NTDs).

This paper describes the development of a class of peptide-based inhibitors as novel antitrypanosomal and antimalarial agents. The inhibitors are based on a characteristic peptide sequence for the inhibition of the cysteine proteases rhodesain of Trypanosoma brucei rhodesiense and falcipain-2 of Plasmodium falciparum. We exploited the reactivity of novel unsaturated electrophilic functions such as vinyl-sulfones, -ketones, -esters, and -nitriles. The Michael acceptors inhibited both rhodesain and falcipain-2, at nanomolar and micromolar levels, respectively. In particular, the vinyl ketone 3b has emerged as a potent rhodesain inhibitor (k2nd = 67 × 106 M-1 min-1), endowed with a picomolar binding affinity (Ki = 38 pM), coupled with a single-digit micromolar activity against Trypanosoma brucei brucei (EC50 = 2.97 µM), thus being considered as a novel lead compound for the discovery of novel effective antitrypanosomal agents.

Amphiphilic Peptide Nanorods Based on Oligo-Phenylalanine as a Biocompatible Drug Carrier.

Peptide nanostructure has been widely explored for drug-delivery systems in recent studies. Peptides possess comparatively lower cytotoxicity and are more efficient than polymeric carriers. Here, we propose a peptide nanorod system, composed of an amphiphilic oligo-peptide RH3F8 (Arg-His3-Phe8), as a drug-delivery carrier. Arginine is an essential amino acid in typical cell-penetration peptides, and histidine induces endo- and lysosomal escape because of its proton sponge effect. Phenylalanine is introduced to provide rich hydrophobicity for stable self-assembly and drug encapsulation. The self-assembled structure of RH3F8 showed nanorod-shaped morphology, positive surface charge, and retained formation in water for 35 days. RH3F8, labeled with Nile Red, showed high cellar uptake and accumulation in both cytoplasm and nucleus. The RH3F8 nanorods demonstrated negligible cytotoxicity, as shown by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and hemolysis assays. To confirm the efficiency of drug delivery, curcumin was encapsulated in the RH3F8 nanorod system (RH3F8-Cur). RH3F8-Cur showed high encapsulation efficiency (24.63%) under the conditions of 200 µM curcumin. The RH3F8-Cur retained nanoscale size and positive surface charge, similar to those of the empty RH3F8 nanorods. RH3F8-Cur displayed a robust anticancer effect in HeLa and A549 cells, and inhibited the proliferation of cancer cells in a zebrafish model. These results indicate that the RH3F8 nanorods may be a promising candidate for a safe and effective drug-delivery system.

Allelopathic effects of exogenous phenylalanine: a comparison of four monocot species.

MAIN CONCLUSION: Exogenous phenylalanine stunted annual ryegrass but not switchgrass or winter grain rye, with deuterium incorporation up to 3% from phenyalanine-d 8 . Toxicity to duckweed varied with illumination intensity and glucose uptake. Isotopic labeling of biomolecules through biosynthesis from deuterated precursors has successfully been employed for both structural studies and metabolic analysis. Phenylalanine is the precursor of many products synthesized by plants, including the monolignols used for synthesis of lignin. Possible allelochemical effects of phenylalanine have not been reported, although its deamination product cinnamic acid is known to have deleterious effects on root elongation and growth of several plant species. The effects of phenylalanine and its deuterated analog phenylalanine-d 8 added to growth media were studied for annual ryegrass (Lolium multiflorum), winter grain rye (Secale cereale), and switchgrass (Panicum virgatum) cultivated under hydroponic conditions. Growth of annual ryegrass was inhibited by phenylalanine while switchgrass and rye were not significantly affected. Growth was less affected by deuterated phenylalanine-d 8 than by its protiated counterpart, which may be a typical deuterium kinetic isotope effect resulting in slower enzymatic reaction rates. Deuterium incorporation levels of 2-3% were achieved in biomass of switchgrass and annual ryegrass. Both protiated and deuterated phenylalanine were moderately toxic (IC25 values 0.6 and 0.8 mM, respectively) to duckweed (Lemna minor) grown using a 12 h diurnal cycle under photoautotrophic conditions. A significant increase in toxicity, greater for the deuterated form, was noted when duckweed was grown under higher intensity, full spectrum illumination with a metal halide lamp compared to fluorescent plant growth lamps emitting in the blue and red spectral regions. Supplementation with glucose increased toxicity of phenylalanine consistent with synergy between hexose and amino acid uptake that has been reported for duckweed.

Parachlorophenylalanine-induced 5-HT depletion alters behavioral and brain neurotransmitters levels in 6-Hz psychomotor seizure model in mice.

The present study was designed to investigate the role of serotonin and other neurotransmitters namely dopamine (DA), histamine, nor-epinephrine (NE), glutamate, and γ-aminobutyric acid (GABA) in the 6-Hz-induced psychomotor seizures in Swiss albino mice. Parachlorophenylalanine (PCPA, 300 mg/kg/day, i.p for 3 days)-treated mice were given 6-Hz stimulation. Sodium valproate (SVP) (200 mg/kg/day, p.o for 3 days) was used as a reference antiepileptic drug. The behavioral changes induced by 6 Hz including increased rearing and grooming, Straub's tail, behavioral arrest, stun position were amplified by PCPA. The 6-Hz-induced seizures were accompanied by reduced brain 5-HT, DA, NE, histamine, GABA, and enhanced glutamate levels. PCPA facilitated further reduction of endogenous 5-HT and DA levels but not NE, histamine, GABA, and glutamate levels. Pre- and post-treatment with SVP protected the mice from 6-Hz seizures and attenuated PCPA-induced changes in the levels of 5-HT and DA in the mice brain suggesting the protective effect of SVP in the pharmacoresistant model of epilepsy involving mainly serotonergic mechanism. However, the study also suggests modulation of other neurotransmitters both in 6-Hz psychomotor seizures and in the action of SVP against such seizures.

Ecotoxicological Perspectives of Sex Determination.

Sex determination or the commitment of the embryo to its sexual fate is a fundamental developmental process with paramount consequences in ecology and evolution. This process, whether triggered by environmental factors or genotypic constitution, can be derailed by environmental contaminants that alter the endocrine system, which is a key component of the regulatory network underlying vertebrate sex determination. Here, we review the molecular basis of sex determination, the endocrine components of its regulation, the maternal and endogenous sources of hormones to the developing embryo, and the routes through which endocrine disrupting chemicals (EDCs) affect gonadal development in reptiles, especially turtles. Among EDCs, we focus on PCBs, BPA, pesticides like atrazine, nitrates, and heavy metals. We also consider whether adaptation might be possible in the face of persistent chemical insult and conclude that, while plausible, contemporary environmental change may outpace adaptive evolution, particularly for many species that are already endangered and suffer from small population sizes.

Nanoparticles based on phenylalanine ethyl ester-alginate conjugate as vitamin B2 delivery system.

Phenylalanine ethyl ester (PAE)-alginate (Alg) conjugate (PAE-Alg, PEA) was synthesized and formation of an amide bond between PAE and Alg was confirmed by Fourier transformed-infrared and (1)H nuclear magnetic resonance spectroscopy. The degree of PAE substitution was 3.5-4.7 (PAE group per hundred sugar residues of Alg) which was determined by elemental analysis. The critical aggregation concentration values determined for PEA conjugates PEA1, PEA2, and PEA3 were 0.20, 0.12, and 0.10 mg/ml, respectively. The particle size of PEA nanoparticles (PEA-NPs) decreased from 425 nm to 226 nm with the increasing degree of PAE substitution. Vitamin B2 (VB2), as a model nutrient, was encapsulated into the nanoparticles. The drug-loading content increased with increasing degree of PAE substitution. The maximum VB2 loading capacity and loading efficiency of PEA3 nanoparticles were 3.53 ± 0.03% and 91.48 ± 0.80%, respectively. The in vitro release behavior of VB2 from the PEA-NPs showed a biphasic release profile with an initial burst release of about 40-50% of VB2 in the first 10 h followed by a steady and continuous release phase for the following 50 h in PBS, pH 7.4. The human colorectal carcinoma cell line was used to investigate the cytotoxicity of PEA-NPs. Our results showed that various concentrations of nanoparticles did not cause significant cytotoxicity against cell lines at normal concentrations.

APC targeted micelle for enhanced intradermal delivery of hepatitis B DNA vaccine.

Chronic hepatitis B is a serious liver disease and puts people at high risk of death from cirrhosis and liver cancer. Although DNA vaccination has been emerged as a potential immunotherapeutic strategy for the treatment of chronic hepatitis B, the efficiencies were not adequate in clinical trials. Here we describe the design, synthesis, and evaluation of mannosylated phenylalanine grafted chitosan (Man-CS-Phe) as a DNA delivery vector for direct transfection of antigen presenting cells to improve cellular and humoral immunity to plasmid-coded antigen. The cationic Man-CS-Phe micelles condense plasmid DNA into nanoscale polyplexes and provide efficient protection of complexed DNA from nuclease degradation. The mannose receptor-mediated enhanced cell uptake and high in vitro transfection efficiency of the polyplexes were demonstrated in RAW 264.7 and DC 2.4 cells using GFP-expressing plasmid DNA. Furthermore, intradermal immunization of BALB/c mice indicated that hepatitis B DNA vaccine/Man-CS-Phe polyplexes not only induced multi-fold higher serum antibody titer in comparison to all other formulations including FuGENE HD, but also significantly stimulated T-cell proliferation and skewed T helper toward Th1 polarization. These results illustrate that the Man-CS-Phe can serve as a promising DNA delivery vector to harness both cellular and humoral arms of immune system.

Protective effect of L-carnitine on Phenylalanine-induced DNA damage.

The pathogenesis and the progression of phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, have been associated with oxidative damage. Moreover, it has been increasingly postulated the antioxidant properties of L-Carnitine (LC). The aim of this study was to verify the effect of LC on Phe-induced DNA damage. The in vitro effect of different concentrations of LC (15, 30, 120 and 150 µM) on DNA damage-induced by high phenylalanine levels (1000 and 2500 µM) was examined in white blood cells from normal individuals using the comet assay. Urinary 8-hydroxydeoguanosine (8-OHdG) levels, a biomarker of oxidative DNA damage, and plasmatic sulfhydryl content were measured in eight patients with classical PKU, under therapy with protein restriction and supplemented with a special formula containing LC, and in controls individuals. Both in vitro tested Phe concentrations (1000 and 2500 µM) have resulted in DNA damage index significantly higher than control group. The in vitro co-treatment with Phe and LC reduced significantly DNA damage index when compared to Phe group. The urinary excretion of 8-OHdG and plasmatic sulfhydryl content presented similar levels in both groups analyzed (controls and treated PKU patients). In treated PKU patients, urinary 8-OHdG levels were positively correlated with blood Phe levels and negatively correlated with blood LC concentration and plasmatic sulfhydryl content. The present work yields experimental evidence that LC can reduce the in vitro DNA injury induced by high concentrations of phenylalanine, as well as, allow to hypothesize that LC protect against DNA damage in patients with PKU.

Blood-brain barrier (BBB) toxicity and permeability assessment after L-(4-¹°Boronophenyl)alanine, a conventional B-containing drug for boron neutron capture therapy, using an in vitro BBB model.

Since brain tumours are the primary candidates for treatment by Boron Neutron Capture Therapy, one major challenge in the selective drug delivery to CNS is the crossing of the blood-brain barrier (BBB). The present pilot study investigated (i) the transport of a conventional B-containing product (i.e., L-(4-(10)Boronophenyl)alanine, L-(10)BPA), already used in medicine but still not fully characterized regarding its CNS interactions, as well as (ii) the effects of the L-(10)BPA on the BBB integrity using an in vitro model, consisting of brain capillary endothelial cells co-cultured with glial cells, closely mimicking the in vivo conditions. The multi-step experimental strategy (i.e. Integrity test, Filter study, Transport assay) checked L-(10)BPA toxicity at 80 µg Boron equivalent/ml, and its ability to cross the BBB, additionally by characterizing the cytoskeletal and TJ's proteins by immunocytochemistry and immunoblotting. In conclusion, a lack of toxic effects of L-(10)BPA was demonstrated, nevertheless accompanied by cellular stress phenomena (e.g. vimentin expression modification), paralleled by a low permeability coefficient (0.39 ± 0.01 × 10(-3)cm min(-1)), corroborating the scarce probability that L-(10)BPA would reach therapeutically effective cerebral concentration. These findings emphasized the need for novel strategies aimed at optimizing boron delivery to brain tumours, trying to ameliorate the compound uptake or developing new targeted products suitable to safely and effectively treat head cancer. Thus, the use of in vitro BBB model for screening studies may provide a useful early safety assessment for new effective compounds.

Co-administration of creatine plus pyruvate prevents the effects of phenylalanine administration to female rats during pregnancy and lactation on enzymes activity of energy metabolism in cerebral cortex and hippocampus of the offspring.

Phenylketonuria (PKU) is the most frequent inborn error of metabolism. It is caused by deficiency in the activity of phenylalanine hydroxylase, leading to accumulation of phenylalanine and its metabolites. Untreated maternal PKU or hyperphenylalaninemia may result in nonphenylketonuric offspring with low birth weight and neonatal sequelae, especially microcephaly and intellectual disability. The mechanisms underlying the neuropathology of brain injury in maternal PKU syndrome are poorly understood. In the present study, we evaluated the possible preventive effect of the co-administration of creatine plus pyruvate on the effects elicited by phenylalanine administration to female Wistar rats during pregnancy and lactation on some enzymes involved in the phosphoryltransfer network in the brain cortex and hippocampus of the offspring at 21 days of age. Phenylalanine administration provoked diminution of body, brain cortex an hippocampus weight and decrease of adenylate kinase, mitochondrial and cytosolic creatine kinase activities. Co-administration of creatine plus pyruvate was effective in the prevention of those alterations provoked by phenylalanine, suggesting that altered energy metabolism may be important in the pathophysiology of maternal PKU. If these alterations also occur in maternal PKU, it is possible that pyruvate and creatine supplementation to the phenylalanine-restricted diet might be beneficial to phenylketonuric mothers.

Thermo-/pH-dual responsive properties of hyperbranched polyethylenimine grafted by phenylalanine.

Novel thermo- and pH-dual responsive amphiphilic copolymers were synthesized based on hyperbranched polyethylenimine (PEI) by grafting L-phenylalanine. The phenylalanine-modified PEI exhibited lower cytotoxicity than commercial PEI. These copolymers showed the phenomena of phase transitions in response to pH and temperature. The dilute copolymer solution at lower pH displayed the higher LCST. Furthermore, LCST increased with the increasing of phenylalanine grafting density. LCST of these copolymers were tunable from 7.2 to 59.6 °C by the degree of amidation and pH of solution. DLS and TEM experiments certified that the copolymer chains aggregated to form small size particles as increasing the temperature above LCST. For these reasons, the obtained smart copolymers were considered to be potential gene/drug carriers in biomedical field.

Motility changes induced by intraluminal FeSO4 in guinea pig jejunum.

BACKGROUND: Dietary iron supplementation is associated with gastrointestinal (GI) side effects including vomiting, nausea, and diarrhea. Although inorganic iron in high concentrations may be damaging to the intestinal mucosa, we hypothesize that there are physiological effects on the GI tract that occur at concentrations achieved by supplementation. Thus, our aim was to investigate the effect of intraluminal ferrous sulfate (FeSO4 ) on jejunal motility. METHODS: Segments of guinea pig jejunum were cannulated and the intraluminal pressure recorded with a transducer, while movements were recorded with a video camera. Peristaltic threshold was the oral pressure that evoked four consecutive propulsive contractions. The nutrients decanoic acid (1 mM), l-phenylalanine (50 mM), or the micronutrient FeSO4 (1 mM) were infused intraluminally. We also tested the effect of FeSO4 on electrochemically detected serotonin (5-HT, 5-hydroxytryptamine) released from in vitro tissues, both at rest and following mechanical stimulation. KEY RESULTS: The jejuna peristaltic threshold was significantly decreased by all three nutrients: FeSO4 : 31 ± 2-23 ± 3 mmH2 O; decanoic acid: 27 ± 2-14 ± 2 mmH2 O; and l-phenylalanine: 30 ± 3-14 ± 3mmH2 O. Of the three, only decanoic acid induced segmentation, while FeSO4 inhibited decanoic acid-induced segmentation. Resting 5-HT release was increased by FeSO4 (128% of control), but mechanically evoked 5-HT release was reduced (70% of control). CONCLUSIONS & INFERENCES: These data suggest that some luminal effects of inorganic iron on jejunal motility could be mediated through a pathway involving altered release of 5-HT. A better understanding of the interaction between luminal iron and 5-HT containing enterochromaffin cells could improve iron supplementation strategies, thus reducing side effects.

Unconjugated bisphenol A cord blood levels in boys with descended or undescended testes.

BACKGROUND: Human toxicity of bisphenol A (BPA), a weak estrogenic environmental endocrine disrupting compound, widely used in plastics, baby bottles, cans and dental sealants, is under investigation. Fetal or perinatal exposure in rodents is associated with programmed adult reproductive diseases. Human epidemiological studies remain scarce, especially concerning testicular development. We have investigated the relationship between fetal exposure to BPA and cryptorchidism. METHODS: Using a radioimmunoassay performed after extraction, validated by high-performance liquid chromatography and mass spectrometry, active levels of unconjugated BPA (uBPA) in cord blood (CB) were measured in 152 boys born after 34 weeks gestation, with cryptorchid or descended testes. RESULTS: Active uBPA was detectable in all CB samples, with values in the control group (n = 106) of 0.14-4.76 ng/ml, median: 0.9 ng/ml; mean ± SD: 1.12 ng/ml ± 0.86 ng/ml, which did not differ from cryptorchid boys (n = 46, 1.26 ± 1.13 ng/ml, P = 0.38). uBPA in controls correlated with CB inhibin B (P < 0.01) and total testosterone (P < 0.05), and with maternal milk polychlorinated bisphenyl 138 (P < 0.03). uBPA did not correlate with clinical maternal or fetal parameters or with other steroid or polypeptide CB hormones assessed. CONCLUSIONS: The presence of uBPA in all CB samples suggests placental transfer and fetal exposure. Similar uBPA levels in the control and cryptorchid groups make the participation of fetal exposure to uBPA in the physiopathology of undescended testes unlikely. However, the observed nanomolar uBPA concentrations support assessment of epidemiological relationships between CB uBPA and other human diseases.

Antimycobacterial activity of UDP-galactopyranose mutase inhibitors.

The galactofuran region of the mycobacterial cell wall consists of alternating 5- and 6-linked beta-d-galactofuranose (beta-D-Galf) residues, essential for viability. UDP-galactofuranose (UDP-Galf), the donor for Galf, is synthesised from UDP-galactopyranose (UDP-Galp) by the enzyme UDP-galactopyranose mutase (UGM), which is not found in humans, rendering it a therapeutic target. The in vitro properties, i.e. enzymatic activity, antimycobacterial activity, cellular toxicity, activity in mycobacterial-infected macrophages and activity against non-replicating persistent mycobacteria, of (4-chlorophenyl)-[1-(4-chlorophenyl)-3-hydroxy-5-methyl-1H-pyrazol-4-yl]-methanone and 3-(4-iodophenyl)-2-[4-(3,4-dichlorophenyl)-thiazol-2-ylamino]-propionic acid were studied. The former compound, a pyrazole, was an inhibitor of UGM from Mycobacterium tuberculosis and Klebsiella pneumoniae and was effective against Mycobacterium smegmatis, Mycobacterium bovis BCG and M. tuberculosis but ineffective against other bacterial strains tested. This compound showed potency against mycobacteria in infected macrophages but exhibited moderate cellular toxicity and was ineffective against non-replicating persistent mycobacteria. This is the first report of a compound both with UGM inhibitory properties and broad antimycobacterial activities. The latter compound, an aminothiazole, was active against UGM from K. pneumoniae and M. tuberculosis but was ineffective against M. bovis BCG or M. tuberculosis as well as demonstrating higher cellular toxicity. These data validate the choice of UGM as a target for active antimycobacterial therapy and confirm the pyrazole compound as a viable lead candidate.

Preparation of photocontrollable, nontoxicity complex of phenylazophenylalanine modified CdS quantum dots with cyclodextrin.

A novel complex of beta-cyclodextrin with phenylazophenylalanine (PAP)-conjugated CdS quantum dot (Fazo-CdS QD) was fabricated for a photocontrollable toxicity study of CdS. Photocontrolling release of Fazo-CdS QDs from the complex was confirmed under UV irradiation by the steady state photoluminescence (PL) spectroscopy. The cytotoxicity of the surface modified CdS QDs was evaluated in vivo. The results suggest that the Fazo-CdS QDs conjugated with beta-CD could be almost nontoxicity, which may have great potential applications in biological labeling and imaging.

Effect of short- and long-term exposition to high phenylalanine blood levels on oxidative damage in phenylketonuric patients.

Phenylketonuria is the most frequent disturbance of amino acid metabolism. Treatment for phenylketonuric patients consists of phenylalanine intake restriction. However, there are patients who do not adhere to treatment and/or are not submitted to neonatal screening. These individuals are more prone to develop brain damage due to long-lasting toxic effects of high levels of phenylalanine and/or its metabolites. Oxidative stress occurs in late-diagnosed phenylketonuric patients, probably contributing to the neurological damage in this disorder. In this work, we aimed to compare the influence of time exposition to high phenylalanine levels on oxidative stress parameters in phenylketonuric patients who did not adhere to protein restricted diet. We evaluated a large spectrum of oxidative stress parameters in plasma and erythrocytes from phenylketonuric patients with early and late diagnosis and of age-matched healthy controls. Erythrocyte glutathione peroxidase activity and glutathione levels, as well as plasma total antioxidant reactivity were significantly reduced in both groups of patients when compared to the control group. Furthermore, protein oxidative damage, measured by carbonyl formation and sulfhydryl oxidation, and lipid peroxidation, determined by malondialdehyde levels, were significantly increased only in patients exposed for a long time to high phenylalanine concentrations, compared to early diagnosed patients and controls. In conclusion, exposition to high phenylalanine concentrations for a short or long time results in a reduction of non-enzymatic and enzymatic antioxidant defenses, whereas protein and lipid oxidative damage only occurs in patients with late diagnosis.