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PubMed1999

Characterization of the meta-cleavage compound hydrolase gene involved in degradation of the lignin-related biphenyl structure by Sphingomonas paucimobilis SYK-6.

Sphingomonas paucimobilis SYK-6 has the ability to transform a lignin-related biphenyl compound, 2,2'-dihydroxy-3,3'-dimethoxy-5, 5'-dicarboxybiphenyl (DDVA), to 5-carboxyvanillic acid (5CVA) via 2, 2',3-trihydroxy-3'-methoxy-5,5'-dicarboxybiphenyl (OH-DDVA). In the 4.9-kb HindIII fragment containing the OH-DDVA meta-cleavage dioxygenase gene (ligZ), we found a novel hydrolase gene (ligY) responsible for the conversion of the meta-cleavage compound of OH-DDVA to 5CVA. Incorporation of 18O from H218O into 5CVA indicated there was a hydrolytic conversion of the OH-DDVA meta-cleavage compound to 5CVA. LigY exhibited hydrolase activity only toward the meta-cleavage compound of OH-DDVA, suggesting its restricted substrate specificity.

Amino Acid Sequence↗
PubMed2005

Passive air sampling of polychlorinated biphenyls, organochlorine compounds, and polybrominated diphenyl ethers across Asia.

Asia is of global importance economically, yet data on ambient persistent organic pollutant levels are still sparse for the region, despite international efforts under the Stockholm Convention to identify and reduce emissions. A large-scale passive air sampling survey was therefore conducted in Asia, specifically in China, Japan, South Korea, and Singapore. Polyurethane foam disks were deployed simultaneously at 77 sites, between Sept 21 and Nov 16, 2004, and analyzed for polychlorinated biphenyls (PCBs), organochlorine compounds (hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), chlordane), and polybrominated diphenyl ethers (PBDEs). The meteorological conditions prevailing in the region at this time facilitated the assessment of local/regional differences in atmospheric emissions, because large-scale advection effects due to monsoons or dust storms did not occur. Air concentrations estimated assuming an average sampler uptake rate of 3.5 m3/day ranged as follows (pg m(-3)): PCBs, 5-340; HCB, 10-460; DDTs, 0.4-1800; chlordanes, 1-660; PBDEs, < 0.13-340. South Korea and Singapore generally had regionally low concentrations. Elevated concentrations of PCBs, DDTs, and HCB occurred at sites in China, higher than reported in a similar recent sampling campaign in Europe. Chlordane was highest in samples from Japan (which also had elevated levels of PCBs and DDTs) and was also elevated in some Chinese locations. PBDE levels were generally low in the region.

Air Pollutants↗
PubMed1984

Microbial biodegradation of 4-chlorobiphenyl, a model compound of chlorinated biphenyls.

The biodegradation products of 4-chlorobiphenyl were analyzed in an Achromobacter sp. strain and a Bacillus brevis strain. Both strains generated the same metabolites, with 4-chlorobenzoic acid as the major metabolic product. Our results corroborate previous observations whereby most bacterial strains degrade the chlorobiphenyls via a major pathway which proceeds by an hydroxylation in position 2,3 and a meta-1,2 fission. However, we also detected several metabolites whose structure suggests the existence of other routes for the degradation of chlorinated biphenyls.

Alcaligenes↗
PubMed2001

Structure-activity relationships of phenylcyclohexene and biphenyl antitubulin compounds against plant and mammalian cells.

Phenylcyclohexenes (PCHs) [e.g., trans-4-nitro-5-(2,3,4-trimethoxyphenyl)cyclohexene, 2d] were found to bind weakly to the colchicine site of bovine tubulin, but are the first mimics of colchicine found to have high activity towards plant cells. Structure-activity relationships for PCHs and biphenyl AC-ring analogues of colchicine (e.g., 2,3,4,4'-tetramethoxy-2'-methyl-1,1'-biphenyl, 3e) are discussed.

Animals↗
PubMed1997

Anti-AIDS agents--XXVI. Structure-activity correlations of gomisin-G-related anti-HIV lignans from Kadsura interior and of related synthetic analogues.

Bioactivity-directed fractionation of an ethanolic extract of the stems of Kadsura interior led to the isolation and identification of 12 known lignans (1-12). Seven of these compounds (1, 6, 8-12) were active as anti-HIV agents. Gomisin-G (11) exhibited the most potent anti-HIV activity with EC50 and therapeutic index (TI) values of 0.006 microgram/mL and 300, respectively. Schisantherin-D (6), kadsuranin (8), and schisandrin-C (10) showed good activity with EC50 values of 0.5, 0.8, and 1.2 micrograms/mL, and TI values of 110, 56, and 33.3, respectively. Ten related synthetic biphenyl compounds, five variously substituted bismethylenedioxy, dimethoxy, and dimethoxycarbonyl isomers (18-22) and five brominated derivatives (23-27) also were evaluated for inhibitory activity against HIV-1 replication in acutely infected H9 cells. The total syntheses of two new isomers (21 and 22) are reported for the first time. The anti-HIV data indicated that the relative position and types of substituents on the phenolic hydroxy groups of either the natural lignans or the synthetic biphenyl compounds rather than the numbers of bromine(s) on the aromatic rings are of primary importance. In the cyclooctane ring of the natural lignans, the position and substitution of hydroxy groups are also important to enhanced anti-HIV activity.

Anti-HIV Agents↗
PubMed2006

Organochlorine compounds (polychlorinated biphenyls and pesticides) and polycyclic aromatic hydrocarbons in populations of Hexaplex trunculus affected by imposex in the lagoon of Venice, Italy.

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were measured in gastropods from the Lagoon of Venice, Italy. The visceral coil and the rest of the soft body of organisms (Hexaplex trunculus) sampled at two stations inside the lagoon and three stations on the seaward side were analyzed to evaluate their contamination levels. Preferential accumulation of PCBs and pesticides in the visceral coil (>80%) compared with the rest of the soft body was observed, whereas on average, PAHs showed no preferential partitioning. Differences between levels of organochlorine contaminants in the gastropods highlighted a gradient of pollution from the stations inside the lagoon (PCBs, 45-363 ng/g; pesticides, 4-51 ng/g) to the sea (PCBs, 13-131 ng/g; pesticides, 2-29 ng/g). The possible role of the three classes of contaminants, in addition to that of organotin compounds (OTCs), previously analyzed in the same samples, in causing one of the anatomic modifications because of imposex in this gastropod also was studied. A modeling approach by partial least squares (PLS) in latent variables was applied to explain the penis length of imposex-affected females with concentrations of organic pollutants. The synergistic role of PCBs, pesticides, and OTCs was evidenced, whereas the contribution of PAHs appeared to be very low.

Animals↗
PubMed1984

Direct chloride measurement of [4-36Cl]chlorobiphenyl and [4,4'-36Cl]dichlorobiphenyl dechlorination in the rat.

A reverse-phase HPLC system was used for the determination of inorganic chloride liberated in vivo from two biphenyl compounds in the rat. Oral administration of [4-36Cl]chlorobiphenyl resulted in a total yield of 27.6% of the original dose excreted over 10 d in the urine and included 1.7% of the dose as inorganic chloride. For [4,4'-36Cl]dichlorobiphenyl, the radioactivity of the original dose in the urine was 39.8% after 10 d, which included 11.5% of the dose as inorganic chloride. These results appear to represent the first direct determination of dechlorination by measurement of the inorganic chloride and suggest that biodechlorination plays a greater role in the metabolism of these compounds than previously expected.

Animals↗
PubMed2000

Inhibition of bacterial peptide deformylase by biaryl acid analogs.

Peptide deformylase is an essential eubacterial metalloenzyme involved in the maturation of proteins by cleaving the N-formyl group from N-blocked methionine polypeptides. Biaryl acid analogs containing tetrazole, acyl sulfonamide, or carboxylate pharmacophores were found to be potent inhibitors of recombinant Escherichia coli peptide deformylase. Two of these compounds, a biphenyl tetrazole, compound 1, and a biphenyl acyl sulfonamide, compound 4, were competitive inhibitors with K(i) values of 1.2 and 6.0 microM, respectively. By analogy to the binding of related compounds to other metalloenzymes such as Bacteroides fragilis metallo-beta-lactamase CcrA and human carbonic anhydrase, a mechanism of inhibition is proposed for these peptide deformylase inhibitors where the acidic moieties form direct ionic interactions with the active site metal cation.

Amidohydrolases↗
PubMed1991

Conformationally restricted polysubstituted biphenyl derivatives with angiotensin II receptors antagonist properties.

The synthesis and in vitro activity of new nonpeptide angiotensin II antagonists is presented. Compared to previously reported biphenyl compounds, the new analogues 8 and 9 have reduced conformational freedom derived from steric hindrance. Methyl 4'-methyl-2',6'-dimethoxy[1,1'-biphenyl]-2-carboxylate 4 has been synthesized by a Von Pechmann condensation of orcinol with oxocyclohexane-2-carboxylate followed by dehydrogenation. This scheme provided the carbon skeleton of the biphenyl potentially substituted on the 2-, 2'-, 4'-, and 6'-positions. Elaboration of the subsituents led to a biphenyl derivative used to alkylate a 2-n-butyl-4-chloro-5-(hydroxymethyl)imidazole. After coupling with the imidazole two regioisomers were separated and identified by 1H NMR. NOESY experiments were useful to establish regiochemistry of the final products that have angiotensin II blocking activity. Their affinity for angiotensin II receptors was established in a binding assay experiment and in an isolated organ test. The presence of 2',6'-dimethoxy substituent on the biphenyl moiety of the antagonist was found to significantly decrease affinity for the receptor.

Angiotensin II↗
PubMed1992

The in vivo and in vitro genotoxicity of aromatic amines in relationship to the genotoxicity of benzidine.

Benzidine and 12 related aromatic amines have been studied for the effects of substituent groups and pi orbital conjugation on their genotoxicity as measured by their mutagenicity in vitro with Salmonella and by chromosomal aberrations (CA) in vivo in the bone-marrow cells of mice. The in vitro studies indicated increases in mutagenicity with increases in the electron withdrawing ability of para' substituents. Mutagenicity also increases with increased conjugation as shown by the degree of planarity of the biphenyl compounds and by comparing the mutagenicities of biphenyl amines to stilbenes as well as to ethylene bridged diphenyl compounds. The relative in vitro mutagenicity results were not predictive of relative in vivo CA results. The 3 most genotoxic compounds in vivo were the conjugated amines without substituents in the para' position. The CA values for 4-aminostilbene were exceptionally high. These in vivo results indicate increased genotoxicity for benzidine analogs without substitution in the para' position.

Aminobiphenyl Compounds↗
PubMed1994

The biomimetic oxidation of beta-1, beta-0-4, beta-5, and biphenyl lignin model compounds by synthetic iron porphyrins.

The degradation of four dimeric lignin model compounds by meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrin iron chloride (TDCSPPFeCl) (2) are reported. 4-Ethoxy-3-methoxyphenylglycerol-beta-guaiacyl ether (3) (a beta-0-4 dimer) was cleaved to give 4-ethoxy-3-methoxybenzaldehyde (4) and guaiacol (5) as major products. The oxidation of 1-(4-ethoxy-3-methoxyphenyl)-2-(4-methoxyphenyl)-1,3-propandiol (6, a beta-1 dimer) gave 4, 4-methoxybenzaldehyde (7), and 4-methoxy-alpha-hydroxyacetophenone (8) as major products. Side chain oxidation and aromatic ring cleavage reactions were found to occur for the phenylcoumaran (alpha-5) model compound, ethyl dehydrodiisoeugenol (12). A biphenyl model compound, 4,4'-diethyldehydrodivanillin (20), was oxidized to give mono- and dicarboxy derivatives, as well as ring-cleaved products of the acid derivatives.

Agaricales↗