Conformational Changes Allow Processing of Bulky Substrates by a Haloalkane Dehalogenase with a Small and Buried Active Site.

PubMed

Kokkonen, Piia; Bednar, David; Dockalova, Veronika; Prokop, Zbynek; Damborsky, Jiri

2018-06-01

Haloalkane dehalogenases catalyze the hydrolysis of halogen-carbon bonds in organic halogenated compounds and as such are of great utility as biocatalysts. The crystal structures of the haloalkane dehalogenase DhlA from the bacterium from Xanthobacter autotrophicus GJ10, specifically adapted for the conversion of the small 1,2-dichloroethane (DCE) molecule, display the smallest catalytic site (110 Å3) within this enzyme family. However, during a substrate-specificity screening, we noted that DhlA can catalyze the conversion of far bulkier substrates, such as the 4-(bromomethyl)-6,7-dimethoxy-coumarin (220 Å3). This large substrate cannot bind to DhlA without conformational alterations. These conformational changes have been previously inferred from kinetic analysis, but their structural basis has not been understood. Using molecular dynamic simulations, we demonstrate here the intrinsic flexibility of part of the cap domain that allows DhlA to accommodate bulky substrates. The simulations displayed two routes for transport of substrates to the active site, one of which requires the conformational change and which is likely the route for bulky substrates. These results provide insights into the structure-dynamics-function relationships in enzymes with deeply buried active sites. Moreover, understanding the structural basis for the molecular adaptation of DhlA to DCE introduced into the biosphere during the industrial revolution provides a valuable lesson in enzyme design by nature. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahl, C.; Morisseau, C; Bomberger, J

Cystic fibrosis transmembrane conductance regulator (CFTR) inhibitory factor (Cif) is a virulence factor secreted by Pseudomonas aeruginosa that reduces the quantity of CFTR in the apical membrane of human airway epithelial cells. Initial sequence analysis suggested that Cif is an epoxide hydrolase (EH), but its sequence violates two strictly conserved EH motifs and also is compatible with other {alpha}/{beta} hydrolase family members with diverse substrate specificities. To investigate the mechanistic basis of Cif activity, we have determined its structure at 1.8-{angstrom} resolution by X-ray crystallography. The catalytic triad consists of residues Asp129, His297, and Glu153, which are conserved across themore » family of EHs. At other positions, sequence deviations from canonical EH active-site motifs are stereochemically conservative. Furthermore, detailed enzymatic analysis confirms that Cif catalyzes the hydrolysis of epoxide compounds, with specific activity against both epibromohydrin and cis-stilbene oxide, but with a relatively narrow range of substrate selectivity. Although closely related to two other classes of {alpha}/{beta} hydrolase in both sequence and structure, Cif does not exhibit activity as either a haloacetate dehalogenase or a haloalkane dehalogenase. A reassessment of the structural and functional consequences of the H269A mutation suggests that Cif's effect on host-cell CFTR expression requires the hydrolysis of an extended endogenous epoxide substrate.« less

Dichloromethane dehalogenase of Hyphomicrobium sp. strain DM2.

PubMed

Kohler-Staub, D; Leisinger, T

1985-05-01

Dichloromethane dehalogenase, a highly inducible glutathione-dependent enzyme catalyzing the conversion of dichloromethane into formaldehyde and inorganic chloride, was purified fivefold with 60% yield from Hyphomicrobium sp. strain DM2. The electrophoretically homogeneous purified enzyme exhibited a specific activity of 17.3 mkat/kg of protein. Its pH optimum was 8.5. The enzyme was stable at -20 degrees C for at least 6 months. A subunit molecular weight of 33,000 was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel filtration of native dichloromethane dehalogenase yielded a molecular weight of 195,000. Subunit cross-linking with dimethyl suberimidate confirmed the hexameric tertiary structure of the enzyme. Dichloromethane dehalogenase was highly specific for dihalomethanes. Its apparent Km values were 30 microM for CH2Cl2, 15 microM for CH2BrCl, 13 microM for CH2Br2, 5 microM for CH2I2, and 320 microM for glutathione. Several chlorinated aliphatic compounds inhibited the dichloromethane dehalogenase activity of the pure enzyme. The Ki values of the competitive inhibitors 1,2-dichloroethane and 1-chloropropane were 3 and 56 microM, respectively.

Dichloromethane dehalogenase of Hyphomicrobium sp. strain DM2.

PubMed Central

Kohler-Staub, D; Leisinger, T

1985-01-01

Dichloromethane dehalogenase, a highly inducible glutathione-dependent enzyme catalyzing the conversion of dichloromethane into formaldehyde and inorganic chloride, was purified fivefold with 60% yield from Hyphomicrobium sp. strain DM2. The electrophoretically homogeneous purified enzyme exhibited a specific activity of 17.3 mkat/kg of protein. Its pH optimum was 8.5. The enzyme was stable at -20 degrees C for at least 6 months. A subunit molecular weight of 33,000 was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel filtration of native dichloromethane dehalogenase yielded a molecular weight of 195,000. Subunit cross-linking with dimethyl suberimidate confirmed the hexameric tertiary structure of the enzyme. Dichloromethane dehalogenase was highly specific for dihalomethanes. Its apparent Km values were 30 microM for CH2Cl2, 15 microM for CH2BrCl, 13 microM for CH2Br2, 5 microM for CH2I2, and 320 microM for glutathione. Several chlorinated aliphatic compounds inhibited the dichloromethane dehalogenase activity of the pure enzyme. The Ki values of the competitive inhibitors 1,2-dichloroethane and 1-chloropropane were 3 and 56 microM, respectively. Images PMID:3988708

Chloroethene degradation and expression of Dehalococcoides dehalogenase genes in cultures originating from Yangtze sediments.

PubMed

Kranzioch, Irene; Ganz, Selina; Tiehm, Andreas

2015-02-01

The anaerobic Dehalococcoides spp. is the only microorganism known to completely dechlorinate the hazardous compounds tetrachloroethene (PCE) or trichloroethene (TCE) via dichloroethene (DCE) and vinyl chloride (VC) to the terminal product, ethene. In this study, growth of Dehalococcoides spp. (DHC) and the expression of DHC dehalogenase genes were demonstrated for Yangtze enrichment cultures. Reductive dechlorination of chloroethenes occurred in Yangtze sediment without the addition of any external auxiliary substrates. All Yangtze enrichment cultures completely dechlorinated PCE and cis-DCE to ethene. To investigate expression of the dehalogenase genes pceA, tceA, vcrA, and bvcA, a protocol for messenger RNA (mRNA) extraction followed by reverse transcription and quantitative PCR analysis was established. During dechlorination, an increase in gene copy numbers of pceA, tceA, and vcrA was observed. However, temporary formation of mRNA was only measured in the case of the dehalogenase genes tceA and vcrA. Comparison of DHC dehalogenase patterns indicated that the Yangtze DHC community does not match any of the previously published enrichment cultures that were obtained from contaminated areas in the USA or Europe.

Armored Enzyme Nanoparticles for Remediation of Subsurface Contaminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jonathan S. Dordick; Jay Grate; Jungbae Kim

2007-02-19

The remediation of subsurface contaminants is a critical problem for the Department of Energy, other government agencies, and our nation. Severe contamination of soil and groundwater exists at several DOE sites due to various methods of intentional and unintentional release. Given the difficulties involved in conventional removal or separation processes, it is vital to develop methods to transform contaminants and contaminated earth/water to reduce risks to human health and the environment. Transformation of the contaminants themselves may involve conversion to other immobile species that do not migrate into well water or surface waters, as is proposed for metals and radionuclides;more » or degradation to harmless molecules, as is desired for organic contaminants. Transformation of contaminated earth (as opposed to the contaminants themselves) may entail reductions in volume or release of bound contaminants for remediation. Research at Rensselaer focused on the development of haloalkane dehalogenase as a critical enzyme in the dehalogenation of contaminated materials (ultimately trichloroethylene and related pollutants). A combination of bioinformatic investigation and experimental work was performed. The bioinformatics was focused on identifying a range of dehalogenase enzymes that could be obtained from the known proteomes of major microorganisms. This work identified several candidate enzymes that could be obtained through relatively straightforward gene cloning and expression approaches. The experimental work focused on the isolation of haloalkane dehalogenase from a Xanthobacter species followed by incorporating the enzyme into silicates to form biocatalytic silicates. These are the precursors of SENs. At the conclusion of the study, dehalogenase was incorporated into SENs, although the loading was low. This work supported a single Ph.D. student (Ms. Philippa Reeder) for two years. The project ended prior to her being able to perform substantive bioinformatics efforts that would identify more promising dehalogenase enzymes. The SEN synthesis, however, was demonstrated to be partially successful with dehalogenases. Further work would provide optimized dehalogenases in SENs for use in pollution remission.« less

CHARACTERIZATION AND APPLICATIONS OF REDUCTIVE DEHALOGENASE GENES IN ENHANCEMENT AND MONITORING OF BIODEGRADATION OF CHLORINATED POLLUTANTS

EPA Science Inventory

Of the currently known reductive dehalogenase genes, few have functions assigned, and it seems likely that many more remain to be discovered. Very little is known of the ecology of the organisms that harbor these genes, that encode enzymes that are key to the anaerobic dechlorina...

Identification of a multi-protein reductive dehalogenase complex in Dehalococcoides mccartyi strain CBDB1 suggests a protein-dependent respiratory electron transport chain obviating quinone involvement.

PubMed

Kublik, Anja; Deobald, Darja; Hartwig, Stefanie; Schiffmann, Christian L; Andrades, Adarelys; von Bergen, Martin; Sawers, R Gary; Adrian, Lorenz

2016-09-01

Dehalococcoides mccartyi strain CBDB1 is an obligate organohalide-respiring bacterium using only hydrogen as electron donor and halogenated organics as electron acceptor. Here, we studied proteins involved in the respiratory chain under non-denaturing conditions. Using blue native gel electrophoresis (BN-PAGE), gel filtration and ultrafiltration an active dehalogenating protein complex with a molecular mass of 250-270 kDa was identified. The active subunit of reductive dehalogenase (RdhA) colocalised with a complex iron-sulfur molybdoenzyme (CISM) subunit (CbdbA195) and an iron-sulfur cluster containing subunit (CbdbA131) of the hydrogen uptake hydrogenase (Hup). No colocalisation between the catalytically active subunits of hydrogenase and reductive dehalogenase was found. By two-dimensional BN/SDS-PAGE the stability of the complex towards detergents was assessed, demonstrating stepwise disintegration with increasing detergent concentrations. Chemical cross-linking confirmed the presence of a higher molecular mass reductive dehalogenase protein complex composed of RdhA, CISM I and Hup hydrogenase and proved to be a potential tool for stabilising protein-protein interactions of the dehalogenating complex prior to membrane solubilisation. Taken together, the identification of the respiratory dehalogenase protein complex and the absence of indications for quinone participation in the respiration suggest a quinone-independent protein-based respiratory electron transfer chain in D. mccartyi. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Biochemistry of Catabolic Reductive Dehalogenation.

PubMed

Fincker, Maeva; Spormann, Alfred M

2017-06-20

A wide range of phylogenetically diverse microorganisms couple the reductive dehalogenation of organohalides to energy conservation. Key enzymes of such anaerobic catabolic pathways are corrinoid and Fe-S cluster-containing, membrane-associated reductive dehalogenases. These enzymes catalyze the reductive elimination of a halide and constitute the terminal reductases of a short electron transfer chain. Enzymatic and physiological studies revealed the existence of quinone-dependent and quinone-independent reductive dehalogenases that are distinguishable at the amino acid sequence level, implying different modes of energy conservation in the respective microorganisms. In this review, we summarize current knowledge about catabolic reductive dehalogenases and the electron transfer chain they are part of. We review reaction mechanisms and the role of the corrinoid and Fe-S cluster cofactors and discuss physiological implications.

Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications.

PubMed

Ang, Thiau-Fu; Maiangwa, Jonathan; Salleh, Abu Bakar; Normi, Yahaya M; Leow, Thean Chor

2018-05-07

The variety of halogenated substances and their derivatives widely used as pesticides, herbicides and other industrial products is of great concern due to the hazardous nature of these compounds owing to their toxicity, and persistent environmental pollution. Therefore, from the viewpoint of environmental technology, the need for environmentally relevant enzymes involved in biodegradation of these pollutants has received a great boost. One result of this great deal of attention has been the identification of environmentally relevant bacteria that produce hydrolytic dehalogenases—key enzymes which are considered cost-effective and eco-friendly in the removal and detoxification of these pollutants. These group of enzymes catalyzing the cleavage of the carbon-halogen bond of organohalogen compounds have potential applications in the chemical industry and bioremediation. The dehalogenases make use of fundamentally different strategies with a common mechanism to cleave carbon-halogen bonds whereby, an active-site carboxylate group attacks the substrate C atom bound to the halogen atom to form an ester intermediate and a halide ion with subsequent hydrolysis of the intermediate. Structurally, these dehalogenases have been characterized and shown to use substitution mechanisms that proceed via a covalent aspartyl intermediate. More so, the widest dehalogenation spectrum of electron acceptors tested with bacterial strains which could dehalogenate recalcitrant organohalides has further proven the versatility of bacterial dehalogenators to be considered when determining the fate of halogenated organics at contaminated sites. In this review, the general features of most widely studied bacterial dehalogenases, their structural properties, basis of the degradation of organohalides and their derivatives and how they have been improved for various applications is discussed.

Reductive dehalogenase structure suggests a mechanism for B12-dependent dehalogenation

PubMed Central

Fisher, Karl; Dunstan, Mark S; Collins, Fraser A; Sjuts, Hanno; Levy, Colin; Hay, Sam; Rigby, Stephen EJ; Leys, David

2015-01-01

Organohalide chemistry underpins many industrial and agricultural processes, and a large proportion of environmental pollutants are organohalides1. Nevertheless, organohalide chemistry is not exclusively of anthropogenic origin, with natural abiotic and biological processes contributing to the global halide cycle2–3. Reductive dehalogenases are responsible for biological dehalogenation in organohalide respiring bacteria4–5, with substrates including the notorious polychlorinated biphenyls (PCBs) or dioxins6–7. These proteins form a distinct subfamily of cobalamin (B12) dependent enzymes that are usually membrane-associated and oxygen-sensitive, hindering detailed studies8–12. We report the characterisation of a soluble, oxygen-tolerant reductive dehalogenase and, by combining structure determination with EPR spectroscopy and simulation, show that a direct interaction between the cobalamin cobalt and the substrate halogen underpins catalysis. In contrast to the carbon-Co bond chemistry catalyzed by the other cobalamin-dependent subfamilies13 we propose that reductive dehalogenases achieve reduction of the organohalide substrate via halogen-Co bond formation. This presents a new paradigm in both organohalide and cobalamin (bio)chemistry that will guide future exploitation of these enzymes in bioremediation or biocatalysis. PMID:25327251

Purifying, cloning and characterizing a novel dehalogenase from Bacillus sp. GZT to enhance the biodegradation of 2,4,6-tribromophenol in water.

PubMed

Liang, Zhishu; Li, Guiying; An, Taicheng

2017-06-01

2,4,6-Tribromophenol (TBP), an intermediate of brominated flame retardants, can easily release to environment and recalcitrant to degradation. Previously, Bacillus sp. GZT, a pure aerobic strain capable of simultaneously debrominating and mineralizing TBP, was successfully isolated by us. To further obtain a practical application and dig up its TBP degradation mechanism, a total of 46.7-fold purification of a novel dehalogenase with a final specific activity of 18.9 U mg -1 and a molecular mass of 63.4 kDa was achieved. Under optimal conditions (35 °C and 200 rpm), up to 80% degradation efficiencies were achieved within 120 min. Adding H 2 O 2 , NADPH, Mn 2+ and Mg 2+ promoted enzyme reaction effectively; while EDTA, methyl viologen, Ni 2+ , Cu 2+ , Ca 2+ and Fe 2+ strongly inhibited reaction activities. The debromination of TBP was catalyzed by the enzyme at a Km of 78 μM and a Vmax of 0.65 min -1  mg protein -1 , which indicated that this dehalogenase could specifically eliminate TBP with a high efficiency and stability. Based on MALDI-TOF/TOF analysis, the dehalogenase shared 98% identity with peptide ABC transporter substrate-binding protein. One open reading frame (ORF) encoding this peptide was found in Strain GZT genome, subjected to clone and expressed in Escherichia coli (E. coli) to characterize the encoding gene. Result showed that this recombinant strain could also remove as similar amount of TBP as Bacillus sp. GZT under the identical condition. Based on these results, we suggest that this newly-isolated TBP dehalogenase highlights a new approach for remediating TBP pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reaction of rat liver glutathione S-transferases and bacterial dichloromethane dehalogenase with dihalomethanes.

PubMed

Blocki, F A; Logan, M S; Baoli, C; Wackett, L P

1994-03-25

Dichloromethane dehalogenase from Methylophilus sp. DM11 is a glutathione S-transferase homolog that is specifically active with dihalomethane substrates. This bacterial enzyme and rat liver glutathione S-transferases were purified to investigate their relative reactivity with CH2Cl2 and related substrates. Rat liver alpha class glutathione transferases were inactive and mu class enzymes showed low activity (7-23 nmol/min/mg of protein) with CH2Cl2. theta class glutathione transferase 5-5 from rat liver and Methylophilus sp. dichloromethane dehalogenase showed specific activities of > or = 1 mumol/min/mg of protein. Apparent Kcat/Km were determined to be 3.3 x 10(4) and 6.0 x 10(4) L M-1 S-1 for the two enzymes, respectively. Dideutero-dichloromethane was processed to dideutereo-formaldehyde, consistent with a nucleophilic halide displacement mechanism. The possibility of a GSCH2X reaction intermediate (GS, glutathione; X, halide) was probed using CH2ClF to generate a more stable halomethylglutathione species (GSCH2F). The reaction of CH2ClF with dichloromethane dehalogenase produced a kinetically identifiable intermediate that decomposed to formaldehyde at a similar rate to synthetic HOCH2CH2SCH2F. 19F-NMR revealed the transient formation of an intermediate identified as GSCH2F by its chemical shift, its triplet resonance, and H-F coupling constant consistent with a fluoromethylthioether. Its decomposition was matched by a stoichiometric formation of fluoride. These studies indicated that the bacterial dichloromethane dehalogenase directs a nucleophilic attack of glutathione on CH2Cl2 to produce a halomethylthioether intermediate. This focuses attention on the mechanism used by theta class glutathione transferases to generate a halomethylthioeter from relatively unreactive dihalomethanes.

Thermophilic archaeal enzymes and applications in biocatalysis.

PubMed

Littlechild, Jennifer A

2011-01-01

Thermophilic enzymes have advantages for their use in commercial applications and particularly for the production of chiral compounds to produce optically pure pharmaceuticals. They can be used as biocatalysts in the application of 'green chemistry'. The thermophilic archaea contain enzymes that have already been used in commercial applications such as the L-aminoacylase from Thermococcus litoralis for the resolution of amino acids and amino acid analogues. This enzyme differs from bacterial L-aminoacylases and has similarities to carboxypeptidases from other archaeal species. An amidase/γ-lactamase from Sulfolobus solfataricus has been used for the production of optically pure γ-lactam, the building block for antiviral carbocyclic nucleotides. This enzyme has similarities to the bacterial signature amidase family. An alcohol dehydrogenase from Aeropyrum pernix has been used for the production of optically pure alcohols and is related to the zinc-containing eukaryotic alcohol dehydrogenases. A transaminase and a dehalogenase from Sulfolobus species have also been studied. The archaeal transaminase is found in a pathway for serine synthesis which is found only in eukaryotes and not in bacteria. It can be used for the asymmetric synthesis of homochiral amines of high enantioselective purity. The L-2-haloacid dehalogenase has applications both in biocatalysis and in bioremediation. All of these enzymes have increased thermostability over their mesophilic counterparts.

Degradation of halogenated aliphatic compounds by Xanthobacter autotrophicus GJ10.

PubMed Central

Janssen, D B; Scheper, A; Dijkhuizen, L; Witholt, B

1985-01-01

A bacterium that is able to utilize a number of halogenated short-chain hydrocarbons and halogenated carboxylic acids as sole carbon source for growth was identified as a strain of Xanthobacter autotrophicus. The organism constitutively produces two different dehalogenases. One enzyme is specific for halogenated alkanes, whereas the other, which is more heat stable and has a higher pH optimum, is specific for halogenated carboxylic acids. Haloalkanes were hydrolyzed in cell extracts to produce alcohols and halide ions, and a route for the metabolism of 1,2-dichlorethane is proposed. Both dehalogenases show a broad substrate specificity, allowing the degradation of bromine- and chlorine-substituted organic compounds. The results show that X. autotrophicus may play a role in the degradation of organochlorine compounds and that hydrolytic dehalogenases may be involved in the microbial metabolism of short-chain halogenated hydrocarbons in microorganisms. Images PMID:3994371

Identification of Two Glutathione-dependent 3,6-Dichlorogentisate Dehalogenases and Their Roles in the Catabolism of the Herbicide Dicamba in Rhizorhabdus dicambivorans Ndbn-20.

PubMed

Li, Na; Tong, Ren-Lei; Yao, Li; Chen, Qing; Yan, Xin; Ding, De-Rong; Qiu, Ji-Guo; He, Jian; Jiang, Jian-Dong

2018-06-22

The herbicide dicamba is initially demethylated to 3,6-dichlorosalicylate (3,6-DCSA) in Rhizorhabdus dicambivorans Ndbn-20 and is subsequently 5-hydroxylated to 3,6-dichlorogentisate (3,6-DCGA). In the present study, two glutathione-dependent 3,6-DCGA dehalogenases, DsmH1 and DsmH2, were identified in strain Ndbn-20. DsmH2 shared low identity (only 31%) with the tetrachlorohydroquinone (TCHQ) dehalogenase PcpC from Sphingobium chlorophenolicum ATCC 39723, while DsmH1 shared high identity (79%) with PcpC. In the phylogenetic tree of related glutathione S-transferases (GSTs), DsmH1 and DsmH2, together with PcpC and the 2,5-dichlorohydroquinone dehalogenase LinD, formed a separate clade. DsmH1 and DsmH2 were synthesized in Escherichia coli BL21 and purified as His-tagged enzymes. Both enzymes required glutathione (GSH) as a co-factor and could 6-dechlorinate 3,6-DCGA to 3-chlorogentisate in vitro DsmH2 had significantly higher catalytic efficiency toward 3,6-DCGA than DsmH1. Transcription and disruption analysis revealed that DsmH2 but not DsmH1 was responsible for the 6-dechlorination of 3,6-DCGA in strain Ndbn-20 in vivo Furthermore, we propose a novel 'eta' class of GSTs to accommodate the four bacterial dehalogenases PcpC, LinD, DsmH1, and DsmH2. IMPORTANCE Dicamba is an important herbicide, and its use and leakage into the environment have dramatically increased since the large-scale planting of genetically modified (GM) dicamba-resistant crops in 2015. However, the complete catabolic pathway of dicamba has remained unknown, which limits its ecotoxicological studies. Our previous study revealed that 3,6-DCGA was an intermediate of dicamba degradation in strain Ndbn-20. In this study, we identified two glutathione-dependent 3,6-DCGA dehalogenases, DsmH1 and DsmH2, and demonstrated that DsmH2 was physiologically responsible for the 6-dechlorination of 3,6-DCGA in strain Ndbn-20. GSTs play an important role in the detoxification and degradation of a variety of endogenous and exogenous toxic compounds. Based on their sequence identities, phylogenetic status and functions, the four bacterial GSH-dependent dehalogenases (PcpC, LinD, DsmH1, and DsmH2) were reclassified as a new 'eta' class of GSTs. This study helps us to elucidate the microbial catabolism of dicamba and enhances our understanding of the diversity and functions of GSTs. Copyright © 2018 American Society for Microbiology.

The uteroglobin fold.

PubMed

Callebaut, I; Poupon, A; Bally, R; Demaret, J P; Housset, D; Delettré, J; Hossenlopp, P; Mornon, J P

2000-01-01

Uteroglobin (UTG) forms a fascinating homodimeric structure that binds small- to medium-sized ligands through an internal hydrophobic cavity, located at the interface between the two monomers. Previous studies have shown that UTG fold is not limited to the UTG/CC10 family, whose sequence/structure relationships are highlighted here, but can be extended to the cap domain of Xanthobacter autotrophicus haloalkane dehalogenase. We show here that UTG fold is adopted by several other cap domains within the alpha/beta hydrolase family, making it a well-suited "geode" structure allowing it to sequester various hydrophobic molecules. Additionally, some data about a new crystal form of oxidized rabbit UTG are presented, completing previous structural studies, as well as results from molecular dynamics, suggesting an alternative way for the ligand to reach the internal cavity.

Insights into the molecular mechanism of dehalogenation catalyzed by D-2-haloacid dehalogenase from crystal structures.

PubMed

Wang, Yayue; Feng, Yanbin; Cao, Xupeng; Liu, Yinghui; Xue, Song

2018-01-23

D-2-haloacid dehalogenases (D-DEXs) catalyse the hydrolytic dehalogenation of D-2-haloacids, releasing halide ions and producing the corresponding 2-hydroxyacids. A structure-guided elucidation of the catalytic mechanism of this dehalogenation reaction has not been reported yet. Here, we report the catalytic mechanism of a D-DEX, HadD AJ1 from Pseudomonas putida AJ1/23, which was elucidated by X-ray crystallographic analysis and the H 2 18 O incorporation experiment. HadD AJ1 is an α-helical hydrolase that forms a homotetramer with its monomer including two structurally axisymmetric repeats. The product-bound complex structure was trapped with L-lactic acid in the active site, which is framed by the structurally related helices between two repeats. Site-directed mutagenesis confirmed the importance of the residues lining the binding pocket in stabilizing the enzyme-substrate complex. Asp205 acts as a key catalytic residue and is responsible for activating a water molecule along with Asn131. Then, the hydroxyl group of the water molecule directly attacks the C2 atom of the substrate to release the halogen ion instead of forming an enzyme-substrate ester intermediate as observed in L-2-haloacid dehalogenases. The newly revealed structural and mechanistic information on D-DEX may inspire structure-based mutagenesis to engineer highly efficient haloacid dehalogenases.

Molecular characterization of the enzymes involved in the degradation of a brominated aromatic herbicide.

PubMed

Chen, Kai; Huang, Linglong; Xu, Changfeng; Liu, Xiaomei; He, Jian; Zinder, Stephen H; Li, Shunpeng; Jiang, Jiandong

2013-09-01

Dehalogenation is the key step in the degradation of halogenated aromatics, while reductive dehalogenation is originally thought to rarely occur in aerobes. In this study, an aerobic strain of Comamonas sp. 7D-2 was shown to degrade the brominated aromatic herbicide bromoxynil completely and release two equivalents of bromides under aerobic conditions. The enzymes involved in the degradation of bromoxynil to 4-carboxy-2-hydroxymuconate-6-semialdehyde, including nitrilase, reductive dehalogenase (BhbA), 4-hydroxybenzoate 3-monooxygenase and protocatechuate 4,5-dioxygenase, were molecularly characterized. The novel dehalogenase BhbA was shown to be a complex of a respiration-linked reductive dehalogenase (RdhA) domain and a NAD(P)H-dependent oxidoreductase domain and to have key features of anaerobic respiratory RdhAs, including two predicted binding motifs for [4Fe-4S] clusters and a close association with a hydrophobic membrane protein (BhbB). BhbB was confirmed to anchor BhbA to the membrane. BhbA was partially purified and found to use NAD(P)H as electron donors. Full-length bhbA homologues were found almost exclusively in marine aerobic proteobacteria, suggesting that reductive dehalogenation occurs extensively in aerobes and that bhbA is horizontally transferred from marine microorganisms. The discovery of a functional reductive dehalogenase and ring-cleavage oxygenases in an aerobe opens up possibilities for basic research as well as the potential application for bioremediation. © 2013 John Wiley & Sons Ltd.

Enhanced degradation of haloacid by heterologous expression in related Burkholderia species.

PubMed

Su, Xianbin; Deng, Liyu; Kong, Ka Fai; Tsang, Jimmy S H

2013-10-01

Haloacids are environmental pollutant and can be transformed to non-toxic alkanoic acids by microbial dehalogenase. Bacterium Burkholderia species MBA4 was enriched from soil for its ability to bioremediate haloacids such as mono-chloroacetate (MCA), mono-bromoacetate (MBA), 2-mono-chloropropionate, and 2-mono-bromopropionate. MBA4 produces an inducible dehalogenase Deh4a that catalyzes the dehalogenation process. The growth of MBA4 on haloacid also relies on the presence of a haloacid-uptake system. Similar dehalogenase genes can be found in the genome of many related species. However, wildtype Burkholderia caribensis MWAP64, Burkholderia phymatum STM815, and Burkholderia xenovorans LB400 were not able to grow on MCA. When a plasmid containing the regulatory and structural gene of Deh4a was transformed to these species, they were able to grow on haloacid. The specific enzyme activities in these recombinants ranges from 2- to 30-fold that of MBA4 in similar condition. Reverse transcription-quantitative real-time PCR showed that the relative transcript levels in these recombinant strains ranges from 9 to over 1,600 times that of MBA4 in similar condition. A recombinant has produced nearly five times of dehalogenase that MBA4 could ever achieve. While the expressions of Deh4a were more relaxed in these phylogenetically related species, an MCA-uptake activity was found to be inducible. These metabolically engineered strains are better degraders than the haloacid-enriched MBA4. Copyright © 2013 Wiley Periodicals, Inc.

Expression, purification and preliminary X-ray characterization of dl-2-haloacid dehalogenase from Methylobacterium sp. CPA1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omi, Rie; Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585; Jitsumori, Keiji

A recombinant form of dl-2-haloacid dehalogenase from Methylobacterium sp. CPA1 has been expressed in E. coli, purified and crystallized. The crystal belongs to space group P6{sub 3}. Diffraction data have been collected to 1.75 Å resolution. dl-2-Haloacid dehalogenase from Methylobacterium sp. CPA1 (dl-DEX Mb) is a unique enzyme that catalyzes the dehalogenation reaction without the formation of an ester intermediate. A recombinant form of dl-DEX Mb has been expressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystal belongs to the hexagonal space group P6{sub 3}, with unit-cell parameters a = b = 186.2, c =more » 114.4 Å. The crystals are likely to contain between four and eight monomers in the asymmetric unit, with a V{sub M} value of 4.20–2.10 Å{sup 3} Da{sup −1}. A self-rotation function revealed peaks on the χ = 180° section. X-ray data have been collected to 1.75 Å resolution.« less

Characterization of the Corrinoid Iron-Sulfur Protein Tetrachloroethene Reductive Dehalogenase of Dehalobacter restrictus

PubMed Central

Maillard, Julien; Schumacher, Wolfram; Vazquez, Francisco; Regeard, Christophe; Hagen, Wilfred R.; Holliger, Christof

2003-01-01

The membrane-bound tetrachloroethene reductive dehalogenase (PCE-RDase) (PceA; EC 1.97.1.8), the terminal component of the respiratory chain of Dehalobacter restrictus, was purified 25-fold to apparent electrophoretic homogeneity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a single band with an apparent molecular mass of 60 ± 1 kDa, whereas the native molecular mass was 71 ± 8 kDa according to size exclusion chromatography in the presence of the detergent octyl-β-d-glucopyranoside. The monomeric enzyme contained (per mol of the 60-kDa subunit) 1.0 ± 0.1 mol of cobalamin, 0.6 ± 0.02 mol of cobalt, 7.1 ± 0.6 mol of iron, and 5.8 ± 0.5 mol of acid-labile sulfur. Purified PceA catalyzed the reductive dechlorination of tetrachloroethene and trichloroethene to cis-1,2-dichloroethene with a specific activity of 250 ± 12 nkat/mg of protein. In addition, several chloroethanes and tetrachloromethane caused methyl viologen oxidation in the presence of PceA. The Km values for tetrachloroethene, trichloroethene, and methyl viologen were 20.4 ± 3.2, 23.7 ± 5.2, and 47 ± 10 μM, respectively. The PceA exhibited the highest activity at pH 8.1 and was oxygen sensitive, with a half-life of activity of 280 min upon exposure to air. Based on the almost identical N-terminal amino acid sequences of PceA of Dehalobacter restrictus, Desulfitobacterium hafniense strain TCE1 (formerly Desulfitobacterium frappieri strain TCE1), and Desulfitobacterium hafniense strain PCE-S (formerly Desulfitobacterium frappieri strain PCE-S), the pceA genes of the first two organisms were cloned and sequenced. Together with the pceA genes of Desulfitobacterium hafniense strains PCE-S and Y51, the pceA genes of Desulfitobacterium hafniense strain TCE1 and Dehalobacter restrictus form a coherent group of reductive dehalogenases with almost 100% sequence identity. Also, the pceB genes, which may code for a membrane anchor protein of PceA, and the intergenic regions of Dehalobacter restrictus and the three desulfitobacteria had identical sequences. Whereas the cprB (chlorophenol reductive dehalogenase) genes of chlorophenol-dehalorespiring bacteria are always located upstream of cprA, all pceB genes known so far are located downstream of pceA. The possible consequences of this feature for the annotation of putative reductive dehalogenase genes are discussed, as are the sequence around the iron-sulfur cluster binding motifs and the type of iron-sulfur clusters of the reductive dehalogenases of Dehalobacter restrictus and Desulfitobacterium dehalogenans identified by electron paramagnetic resonance spectroscopy. PMID:12902251

Structure-function studies on the active site of the coelenterazine-dependent luciferase from Renilla.

PubMed

Woo, Jongchan; Howell, Matthew H; von Arnim, Albrecht G

2008-04-01

Renilla luciferase (RLUC) is a versatile tool for gene expression assays and in vivo biosensor applications, but its catalytic mechanism remains to be elucidated. RLUC is evolutionarily related to the alpha/beta hydrolase family. Its closest known homologs are bacterial dehalogenases, raising the question of how a protein with a hydrolase fold can function as a decarboxylating oxygenase. Molecular docking simulations with the coelenterazine substrate against an RLUC homology model as well as a recently determined RLUC crystal structure were used to build hypotheses to identify functionally important residues, which were subsequently tested by site-directed mutagenesis, heterologous expression, and bioluminescence emission spectroscopy. The data highlighted two triads of residues that are critical for catalysis. The putative catalytic triad residues D120, E144, and H285 bear only limited resemblance to those found in the active site of aequorin, a coelenterazine-utilizing photoprotein, suggesting that the reaction scheme employed by RLUC differs substantially from the one established for aequorin. The role of H285 in catalysis was further supported by inhibition using diethylpyrocarbonate. Multiple substitutions of N53, W121, and P220--three other residues implicated in product binding in the homologous dehalogenase Sphingomonas LinB--also supported their involvement in catalysis. Together with luminescence spectra, our data lead us to propose that the conserved catalytic triad of RLUC is directly involved in the decarboxylation reaction of coelenterazine to produce bioluminescence, while the other active-site residues are used for binding of the substrate.

Molecular Bases of Enantioselectivity of Haloalkane Dehalogenase DbjA

NASA Astrophysics Data System (ADS)

Sato, Yukari; Natsume, Ryo; Prokop, Zbynek; Brezovsky, Jan; Chaloupkova, Radka; Damborsky, Jiri; Nagata, Yuji; Senda, Toshiya

Enzymes are widely used for the synthesis of pharmaceuticals, agrochemicals, and food additives because they can catalyze high enantioselective transformations. In order to construct selective enzymes by protein engineering, it is important to understand the molecular basis of enzyme-substrate interactions that contribute to enantioselectivity. The haloalkane dehalogenase DbjA showed high enantioselectivity for two racemic mixtures: α-bromoesters and β-bromoalkanes. Thermodynamic analysis, protein crystallography, and computer simulations indicated that DbjA carries two bases for the enantiodiscrimination of each racemic mixture. This study helps us understand the molecular basis of the enantioselectivity and opens up new possibilities for constructing enantiospecific biocatalysts through protein engineering.

A metagenomic-based survey of microbial (de)halogenation potential in a German forest soil

PubMed Central

Weigold, Pascal; El-Hadidi, Mohamed; Ruecker, Alexander; Huson, Daniel H.; Scholten, Thomas; Jochmann, Maik; Kappler, Andreas; Behrens, Sebastian

2016-01-01

In soils halogens (fluorine, chlorine, bromine, iodine) are cycled through the transformation of inorganic halides into organohalogen compounds and vice versa. There is evidence that these reactions are microbially driven but the key enzymes and groups of microorganisms involved are largely unknown. Our aim was to uncover the diversity, abundance and distribution of genes encoding for halogenating and dehalogenating enzymes in a German forest soil by shotgun metagenomic sequencing. Metagenomic libraries of three soil horizons revealed the presence of genera known to be involved in halogenation and dehalogenation processes such as Bradyrhizobium or Pseudomonas. We detected a so far unknown diversity of genes encoding for (de)halogenating enzymes in the soil metagenome including specific and unspecific halogenases as well as metabolic and cometabolic dehalogenases. Genes for non-heme, no-metal chloroperoxidases and haloalkane dehalogenases were the most abundant halogenase and dehalogenase genes, respectively. The high diversity and abundance of (de)halogenating enzymes suggests a strong microbial contribution to natural halogen cycling. This was also confirmed in microcosm experiments in which we quantified the biotic formation of chloroform and bromoform. Knowledge on microorganisms and genes that catalyze (de)halogenation reactions is critical because they are highly relevant to industrial biotechnologies and bioremediation applications. PMID:27353292

Specificity and kinetics of haloalkane dehalogenase.

PubMed

Schanstra, J P; Kingma, J; Janssen, D B

1996-06-21

Haloalkane dehalogenase converts halogenated alkanes to their corresponding alcohols. The active site is buried inside the protein and lined with hydrophobic residues. The reaction proceeds via a covalent substrate-enzyme complex. This paper describes a steady-state and pre-steady-state kinetic analysis of the conversion of a number of substrates of the dehalogenase. The kinetic mechanism for the "natural" substrate 1,2-dichloroethane and for the brominated analog and nematocide 1,2-dibromoethane are given. In general, brominated substrates had a lower Km, but a similar kcat than the chlorinated analogs. The rate of C-Br bond cleavage was higher than the rate of C-Cl bond cleavage, which is in agreement with the leaving group abilities of these halogens. The lower Km for brominated compounds therefore originates both from the higher rate of C-Br bond cleavage and from a lower Ks for bromo-compounds. However, the rate-determining step in the conversion (kcat) of 1, 2-dibromoethane and 1,2-dichloroethane was found to be release of the charged halide ion out of the active site cavity, explaining the different Km but similar kcat values for these compounds. The study provides a basis for the analysis of rate-determining steps in the hydrolysis of various environmentally important substrates.

Comparative proteomic analysis of virulent Korean Mycobacterium tuberculosis K-strain with other mycobacteria strain following infection of U-937 macrophage.

PubMed

Ryoo, Sung Weon; Park, Young Kil; Park, Sue-Nie; Shim, Young Soo; Liew, Hyunjeong; Kang, Seongman; Bai, Gill-Han

2007-06-01

In Korea, the Mycobacterium tuberculosis K-strain is the most prevalent clinical isolates and belongs to the Beijing family. In this study, we conducted comparative porteomics of expressed proteins of clinical isolates of the K-strain with H37Rv, H37Ra as well as the vaccine strain of Mycobacterium bovis BCG following phagocytosis by the human monocytic cell line U-937. Proteins were analyzed by 2-D PAGE and MALDITOF-MS. Two proteins, Mb1363 (probable glycogen phosphorylase GlgP) and MT2656 (Haloalkane dehalogenase LinB) were most abundant after phagocytosis of M. tuberculosis K-strain. This approach provides a method to determine specific proteins that may have critical roles in tuberculosis pathogenesis.

Crystallographic analysis of 1,2,3-trichloropropane biodegradation by the haloalkane dehalogenase DhaA31.

PubMed

Lahoda, Maryna; Mesters, Jeroen R; Stsiapanava, Alena; Chaloupkova, Radka; Kuty, Michal; Damborsky, Jiri; Kuta Smatanova, Ivana

2014-02-01

Haloalkane dehalogenases catalyze the hydrolytic cleavage of carbon-halogen bonds, which is a key step in the aerobic mineralization of many environmental pollutants. One important pollutant is the toxic and anthropogenic compound 1,2,3-trichloropropane (TCP). Rational design was combined with saturation mutagenesis to obtain the haloalkane dehalogenase variant DhaA31, which displays an increased catalytic activity towards TCP. Here, the 1.31 Å resolution crystal structure of substrate-free DhaA31, the 1.26 Å resolution structure of DhaA31 in complex with TCP and the 1.95 Å resolution structure of wild-type DhaA are reported. Crystals of the enzyme-substrate complex were successfully obtained by adding volatile TCP to the reservoir after crystallization at pH 6.5 and room temperature. Comparison of the substrate-free structure with that of the DhaA31 enzyme-substrate complex reveals that the nucleophilic Asp106 changes its conformation from an inactive to an active state during the catalytic cycle. The positions of three chloride ions found inside the active site of the enzyme indicate a possible pathway for halide release from the active site through the main tunnel. Comparison of the DhaA31 variant with wild-type DhaA revealed that the introduced substitutions reduce the volume and the solvent-accessibility of the active-site pocket.

Haloalkane hydrolysis with an immobilized haloalkane dehalogenase.

PubMed

Dravis, B C; Swanson, P E; Russell, A J

2001-11-20

Haloalkane dehalogenase from Rhodococcus rhodochrous was covalently immobilized onto a polyethyleneimine impregnated gamma-alumina support. The dehalogenating enzyme was found to retain greater than 40% of its original activity after immobilization, displaying an optimal loading (max. activity/supported protein) of 70 to 75 mg/g with an apparent maximum (max. protein/support) of 156 mg/g. The substrate, 1,2,3-trichloropropane, was found to favorably partition (adsorb) onto the inorganic alumina carrier (10 to 20 mg/g), thereby increasing the local reactant concentration with respect to the catalyst's environment, whereas the product, 2,3-dichloropropan-1-ol, demonstrated no affinity. Additionally, the inorganic alumina support exhibited no adverse effects because of solvent/component incompatibilities or deterioration due to pH variance (pH 7.0 to 10.5). As a result of the large surface area to volume ratio of the support matrix and the accessibility of the bound protein, the immobilized biocatalyst was not subject to internal mass transfer limitations. External diffusional restrictions could be eliminated with simple agitation (mixing speed: 50 rpm; flux: 4.22 cm/min). The pH-dependence of the immobilized dehalogenase was essentially the same as that for the native enzyme. Finally, both the thermostability and resistance toward inactivation by organic solvent were improved by more than an order of magnitude after immobilization. Copyright 2001 John Wiley & Sons, Inc.

Specificity in transition state binding: the Pauling model revisited.

PubMed

Amyes, Tina L; Richard, John P

2013-03-26

Linus Pauling proposed that the large rate accelerations for enzymes are caused by the high specificity of the protein catalyst for binding the reaction transition state. The observation that stable analogues of the transition states for enzymatic reactions often act as tight-binding inhibitors provided early support for this simple and elegant proposal. We review experimental results that support the proposal that Pauling's model provides a satisfactory explanation for the rate accelerations for many heterolytic enzymatic reactions through high-energy reaction intermediates, such as proton transfer and decarboxylation. Specificity in transition state binding is obtained when the total intrinsic binding energy of the substrate is significantly larger than the binding energy observed at the Michaelis complex. The results of recent studies that aimed to characterize the specificity in binding of the enolate oxygen at the transition state for the 1,3-isomerization reaction catalyzed by ketosteroid isomerase are reviewed. Interactions between pig heart succinyl-coenzyme A:3-oxoacid coenzyme A transferase (SCOT) and the nonreacting portions of coenzyme A (CoA) are responsible for a rate increase of 3 × 10(12)-fold, which is close to the estimated total 5 × 10(13)-fold enzymatic rate acceleration. Studies that partition the interactions between SCOT and CoA into their contributing parts are reviewed. Interactions of the protein with the substrate phosphodianion group provide an ~12 kcal/mol stabilization of the transition state for the reactions catalyzed by triosephosphate isomerase, orotidine 5'-monophosphate decarboxylase, and α-glycerol phosphate dehydrogenase. The interactions of these enzymes with the substrate piece phosphite dianion provide a 6-8 kcal/mol stabilization of the transition state for reaction of the appropriate truncated substrate. Enzyme activation by phosphite dianion reflects the higher dianion affinity for binding to the enzyme-transition state complex compared with that of the free enzyme. Evidence is presented that supports a model in which the binding energy of the phosphite dianion piece, or the phosphodianion group of the whole substrate, is utilized to drive an enzyme conformational change from an inactive open form E(O) to an active closed form E(C), by closure of a phosphodianion gripper loop. Members of the enolase and haloalkanoic acid dehalogenase superfamilies use variable capping domains to interact with nonreacting portions of the substrate and sequester the substrate from interaction with bulk solvent. Interactions of this capping domain with the phenyl group of mandelate have been shown to activate mandelate racemase for catalysis of deprotonation of α-carbonyl carbon. We propose that an important function of these capping domains is to utilize the binding interactions with nonreacting portions of the substrate to activate the enzyme for catalysis.

Specificity in Transition State Binding: The Pauling Model Revisited

PubMed Central

Amyes, Tina L.; Richard, John P.

2013-01-01

Linus Pauling proposed that the large rate accelerations for enzymes are due to the high specificity of the protein catalyst for binding the reaction transition state. The observation that stable analogs of the transition states for enzymatic reactions often act as tight-binding binding inhibitors provided early support for this simple and elegant proposal. We review experimental results which support the proposal that Pauling’s model provides a satisfactory explanation for the rate accelerations for many heterolytic enzymatic reactions through high energy reaction intermediates, such as proton transfer and decarboxylation. Specificity in transition state binding is obtained when the total intrinsic binding energy of the substrate is significantly larger than the binding energy observed at the Michaelis complex. The results of recent studies to characterize the specificity in binding of the enolate oxygen at the transition state for the 1,3-isomerization reaction catalyzed by ketosteroid isomerase are reviewed. Interactions between pig heart succinyl-CoA:3-oxoacid coenzyme A transferase (SCOT) and the nonreacting portions of CoA are responsible for a rate increase of 3 × 1012-fold, which is close to the estimated total 5 × 1013-fold enzymatic rate acceleration. Studies that partition the interactions between SCOT and CoA into their contributing parts are reviewed. Interactions of the protein with the substrate phosphodianion group provide a ca. 12 kcal/mol stabilization of the transition state for the reactions catalyzed by triosephosphate isomerase, orotidine 5′-monophosphate decarboxylase and α-glycerol phosphate dehydrogenase. The interactions of these enzymes with the substrate piece phosphite dianion provide a 6 – 8 kcal/mol stabilization of the transition state for reaction of the appropriate truncated substrate. Enzyme activation by phosphite dianion reflects the higher dianion affinity for binding to the enzyme-transition state complex compared with the free enzyme. Evidence is presented that supports a model in which the binding energy of the phosphite dianion piece, or the phosphodianion group of the whole substrate, is utilized to drive an enzyme conformational change from an inactive open form EO to an active closed form EC, by closure of a phosphodianion gripper loop. Members of the enolase and haloalkanoic acid dehalogenase superfamilies use variable capping domains to interact with nonreacting portions of the substrate and sequester the substrate from interaction with bulk solvent. Interactions of this capping domain with the phenyl group of mandelate have been shown to activate mandelate racemase for catalysis of deprotonation of α-carbonyl carbon. We propose that an important function of these capping domains is to utilize the binding interactions with nonreacting portions of the substrate to activate the enzyme for catalysis. PMID:23327224

Dehalogenation Activities and Distribution of Reductive Dehalogenase Homologous Genes in Marine Subsurface Sediments▿ †

PubMed Central

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H.; Inagaki, Fumio

2009-01-01

Halogenated organic compounds serve as terminal electron acceptors for anaerobic respiration in a diverse range of microorganisms. Here, we report on the widespread distribution and diversity of reductive dehalogenase homologous (rdhA) genes in marine subsurface sediments. A total of 32 putative rdhA phylotypes were detected in sediments from the southeast Pacific off Peru, the eastern equatorial Pacific, the Juan de Fuca Ridge flank off Oregon, and the northwest Pacific off Japan, collected at a maximum depth of 358 m below the seafloor. In addition, significant dehalogenation activity involving 2,4,6-tribromophenol and trichloroethene was observed in sediment slurry from the Nankai Trough Forearc Basin. These results suggest that dehalorespiration is an important energy-yielding pathway in the subseafloor microbial ecosystem. PMID:19749069

Dehalogenation activities and distribution of reductive dehalogenase homologous genes in marine subsurface sediments.

PubMed

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H; Inagaki, Fumio

2009-11-01

Halogenated organic compounds serve as terminal electron acceptors for anaerobic respiration in a diverse range of microorganisms. Here, we report on the widespread distribution and diversity of reductive dehalogenase homologous (rdhA) genes in marine subsurface sediments. A total of 32 putative rdhA phylotypes were detected in sediments from the southeast Pacific off Peru, the eastern equatorial Pacific, the Juan de Fuca Ridge flank off Oregon, and the northwest Pacific off Japan, collected at a maximum depth of 358 m below the seafloor. In addition, significant dehalogenation activity involving 2,4,6-tribromophenol and trichloroethene was observed in sediment slurry from the Nankai Trough Forearc Basin. These results suggest that dehalorespiration is an important energy-yielding pathway in the subseafloor microbial ecosystem.

The Membrane-Bound C Subunit of Reductive Dehalogenases: Topology Analysis and Reconstitution of the FMN-Binding Domain of PceC

PubMed Central

Buttet, Géraldine F.; Willemin, Mathilde S.; Hamelin, Romain; Rupakula, Aamani; Maillard, Julien

2018-01-01

Organohalide respiration (OHR) is the energy metabolism of anaerobic bacteria able to use halogenated organic compounds as terminal electron acceptors. While the terminal enzymes in OHR, so-called reductive dehalogenases, are well-characterized, the identity of proteins potentially involved in electron transfer to the terminal enzymes remains elusive. Among the accessory genes identified in OHR gene clusters, the C subunit (rdhC) could well code for the missing redox protein between the quinol pool and the reductive dehalogenase, although it was initially proposed to act as transcriptional regulator. RdhC sequences are characterized by the presence of multiple transmembrane segments, a flavin mononucleotide (FMN) binding motif and two conserved CX3CP motifs. Based on these features, we propose a curated selection of RdhC proteins identified in general sequence databases. Beside the Firmicutes from which RdhC sequences were initially identified, the identified sequences belong to three additional phyla, the Chloroflexi, the Proteobacteria, and the Bacteriodetes. The diversity of RdhC sequences mostly respects the phylogenetic distribution, suggesting that rdhC genes emerged relatively early in the evolution of the OHR metabolism. PceC, the C subunit of the tetrachloroethene (PCE) reductive dehalogenase is encoded by the conserved pceABCT gene cluster identified in Dehalobacter restrictus PER-K23 and in several strains of Desulfitobacterium hafniense. Surfaceome analysis of D. restrictus cells confirmed the predicted topology of the FMN-binding domain (FBD) of PceC that is the exocytoplasmic face of the membrane. Starting from inclusion bodies of a recombinant FBD protein, strategies for successful assembly of the FMN cofactor and refolding were achieved with the use of the flavin-trafficking protein from D. hafniense TCE1. Mass spectrometry analysis and site-directed mutagenesis of rFBD revealed that threonine-168 of PceC is binding FMN covalently. Our results suggest that PceC, and more generally RdhC proteins, may play a role in electron transfer in the metabolism of OHR. PMID:29740408

Inherited hypothyroidism.

PubMed

Jackson, I M

1976-03-01

Familial hypothyroidism results from both thyroidal and extrathyroidal dysfunction. Specific intrathyroidal abnormalities in thyroid hormone synthesis causing goitrous hypothyroidism are iodide trap defect, organification defect, "coupling" defect, iodoprotein defect, and dehalogenase defect. The diagnostic studies for each are outlined utilizing radioiodine(131I) studies. Other causes of cretinism include failure of the thyroid gland to respond to TSH and lack of pituitary TSH (or hypothalamic TRH). The syndrome of peripheral resistance to thyroid hormone is discussed. The diagnosis of inherited hypothyrodism rests on an adequate family history and measurement of both T4 and TSH levels which can be determined in cord blood or peripheral blood from the infant. The importance of early treatment of hypothyroidism in the neonatal period to prevent brain damage is emphasized. The rec:nt discovery of the importance of reverse T3 (RT3) in fetal thyroid metabolism is described, and the possibility of amniocentesis as an aid in prenatal diagnosis is considered. The place of intrauterine administration of thyroid hormone to the fetus at risk from hypothyroidism is uncertain at this time and requires carefully controlled studies and long-term follow-up.

Enhancing the biocatalytic manufacture of the key intermediate of atorvastatin by focused directed evolution of halohydrin dehalogenase.

PubMed

Luo, Yu; Chen, Yangzi; Ma, Hongmin; Tian, ZhenHua; Zhang, Yeqi; Zhang, Jian

2017-02-06

Halohydrin dehalogenases (HHDHs) are biocatalytically interesting enzymes due to their ability to form C-C, C-N, C-O, and C-S bonds. One of most important application of HHDH was the protein engineering of HheC (halohydrin dehalogenase from Agrobacterium radiobacter AD1) for the industrial manufacturing of ethyl (R)-4-cyano-3-hydroxybutanoate (HN), a key chiral synthon of a cholesterol-lowering drug of atorvastatin. During our development of an alternative, more efficient and economic route for chemo-enzymatic preparation of the intermediate of atorvastatin, we found that the HheC2360 previously reported for HN manufacture, had insufficient activity for the cyanolysis production of tert-butyl (3 R,5 S)-6-cyano-3,5-dihydroxyhexanoate (A7). Herein, we present the focused directed evolution of HheC2360 with higher activity and enhanced biocatalytic performance using active site mutagenesis. Through docking of the product, A7, into the crystal structure of HheC2360, 6 residues was selected for combined active sites testing (CASTing). After library screening, the variant V84G/W86F was identified to have a 15- fold increase in activity. Time course analysis of the cyanolysis reaction catalyzed by this variant, showed 2- fold increase in space time productivity compared with HheC2360. These results demonstrate the applicability of the variant V84G/W86F as a biocatalyst for the efficient and practical production of atorvastatin intermediate.

Anaerobic reductive dechlorination of tetrachloroethene: how can dual Carbon-Chlorine isotopic measurements help elucidating the underlying reaction mechanism?

NASA Astrophysics Data System (ADS)

Badin, Alice; Buttet, Géraldine; Maillard, Julien; Holliger, Christof; Hunkeler, Daniel

2014-05-01

Chlorinated ethenes (CEs) such as tetrachloroethene (PCE) are common persistent groundwater contaminants. Among clean-up strategies applied to sites affected by such pollution, bioremediation has been considered with a growing interest as it represents a cost-effective, environmental friendly approach. This technique however sometimes leads to an incomplete and slow biodegradation of CEs resulting in an accumulation of toxic metabolites. Understanding the reaction mechanisms underlying anaerobic reductive dechlorination would thus help assessing PCE biodegradation in polluted sites. Stable isotope analysis can provide insight into reaction mechanisms. For chlorinated hydrocarbons, carbon (C) and chlorine (Cl) isotope data (δ13C and δ37Cl) tend to show a linear correlation with a slope (m ≡ ɛC/ɛCl) characteristic of the reaction mechanism [1]. This study hence aims at exploring the potential of a dual C-Cl isotope approach in the determination of the reaction mechanisms involved in PCE reductive dechlorination. C and Cl isotope fractionation were investigated during anaerobic PCE dechlorination by two bacterial consortia containing members of the Sulfurospirillum genus. The specificity in these consortia resides in the fact that they each conduct PCE reductive dechlorination catalysed by one different reductive dehalogenase, i.e. PceADCE which yields trichloroethene (TCE) and cis-dichloroethene (cDCE), and PceATCE which yields TCE only. The bulk C isotope enrichment factors were -3.6±0.3 o for PceATCE and -0.7±0.1o for PceADCE. The bulk Cl isotope enrichment factors were -1.3±0.2 o for PceATCE and -0.9±0.1 o for PceADCE. When applying the dual isotope approach, two m values of 2.7±0.1 and 0.7±0.2 were obtained for the reductive dehalogenases PceATCE and PceADCE, respectively. These results suggest that PCE can be degraded according to two different mechanisms. Furthermore, despite their highly similar protein sequences, each reductive dehalogenase seems to catalyse PCE reductive dechlorination according to a different mechanism. In another study, an m value of 2.5±0.8 was found for PCE anaerobic dechlorination by a bacterial consortium dominated by species closely related to Desulfitobacterium aromaticivorans strain UKTL (consortia A) [2]. This value is indistinguishable from the one found for PceATCE within a 95% confidence interval although the reductive dehalogenase protein sequence of consortia A is distinctly different from the sequences of our two cultures. This suggests that the reaction mechanism is not related to the similarities between reductive dehalogenases. References 1. Abe, Y., et al., Carbon and Chlorine Isotope Fractionation during Aerobic Oxidation and Reductive Dechlorination of Vinyl Chloride and cis-1,2-Dichloroethene. Environmental Science & Technology, 2009. 43(1): p. 101-107. 2. Wiegert, C., et al., Carbon and Chlorine Isotope Fractionation During Microbial Degradation of Tetra- and Trichloroethene. Environmental Science & Technology, 2013. 47(12): p. 6449-6456.

Biominerlization and possible endosulfan degradation pathway adapted by Aspergillus niger.

PubMed

Bhalerao, Tejomyee S

2013-11-28

Endosulfan is a chlorinated pesticide; its persistence in the environment and toxic effects on biota are demanding its removal. This study aims at improving the tolerance of the previously isolated fungus Aspergillus niger (A. niger) ARIFCC 1053 to endosulfan. Released chloride, dehalogenase activity, and released proteins were estimated along with analysis of endosulfan degradation and pathway identification. The culture could tolerate 1,000 mg/ml of technical grade endosulfan. Complete disappearance of endosulfan was seen after 168 h of incubation. The degradation study could easily be correlated with increase in released chlorides, dehalogenase activity and protein released. Comparative infrared spectral analysis suggested that the molecule of endosulfan was degraded efficiently by A. niger ARIFCC 1053. Obtained mass ion values by GC-MS suggested a hypothetical pathway during endosulfan degradation by A. niger ARIFCC 1053. All these results provide a basis for the development of bioremediation strategies to remediate the pollutant under study in the environment.

Regio- and Enantioselective Sequential Dehalogenation of rac-1,3-Dibromobutane by Haloalkane Dehalogenase LinB.

PubMed

Gross, Johannes; Prokop, Zbyněk; Janssen, Dick; Faber, Kurt; Hall, Mélanie

2016-08-03

The hydrolytic dehalogenation of rac-1,3-dibromobutane catalyzed by the haloalkane dehalogenase LinB from Sphingobium japonicum UT26 proceeds in a sequential fashion: initial formation of intermediate haloalcohols followed by a second hydrolytic step to produce the final diol. Detailed investigation of the course of the reaction revealed favored nucleophilic displacement of the sec-halogen in the first hydrolytic event with pronounced R enantioselectivity. The second hydrolysis step proceeded with a regioselectivity switch at the primary position, with preference for the S enantiomer. Because of complex competition between all eight possible reactions, intermediate haloalcohols formed with moderate to good ee ((S)-4-bromobutan-2-ol: up to 87 %). Similarly, (S)-butane-1,3-diol was formed at a maximum ee of 35 % before full hydrolysis furnished the racemic diol product. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Degradation of n-haloalkanes and alpha, omega-dihaloalkanes by wild-type and mutants of Acinetobacter sp. strain GJ70.

PubMed Central

Janssen, D B; Jager, D; Witholt, B

1987-01-01

A 1,6-dichlorohexane-degrading strain of Acinetobacter sp. was isolated from activated sludge. The organism could grow with and quantitatively release halide from 1,6-dichlorohexane, 1,9-dichlorononane, 1-chloropentane, 1-chlorobutane, 1-bromopentane, ethylbromide, and 1-iodopropane. Crude extracts contained an inducible novel dehalogenase that liberated halide from the above compounds and also from 1,3-dichloropropane, 1,2-dibromoethane, and 2-bromoethanol. The latter two compounds were toxic suicide substrates for the organism at concentrations of 10 and 5 microM, respectively. Mutants resistant to 1,2-dibromoethane (3 mM) lacked dehalogenase activity and did not utilize haloalkanes for growth. Mutants resistant to both 1,2-dibromoethane (3 mM) and 2-bromoethanol (30 mM) could no longer oxidize or utilize alcohols and were capable of hydrolytic dehalogenation of 1,2-dibromoethane to ethylene glycol. PMID:3579270

Organohalide Respiring Bacteria and Reductive Dehalogenases: Key Tools in Organohalide Bioremediation

PubMed Central

Jugder, Bat-Erdene; Ertan, Haluk; Bohl, Susanne; Lee, Matthew; Marquis, Christopher P.; Manefield, Michael

2016-01-01

Organohalides are recalcitrant pollutants that have been responsible for substantial contamination of soils and groundwater. Organohalide-respiring bacteria (ORB) provide a potential solution to remediate contaminated sites, through their ability to use organohalides as terminal electron acceptors to yield energy for growth (i.e., organohalide respiration). Ideally, this process results in non- or lesser-halogenated compounds that are mostly less toxic to the environment or more easily degraded. At the heart of these processes are reductive dehalogenases (RDases), which are membrane bound enzymes coupled with other components that facilitate dehalogenation of organohalides to generate cellular energy. This review focuses on RDases, concentrating on those which have been purified (partially or wholly) and functionally characterized. Further, the paper reviews the major bacteria involved in organohalide breakdown and the evidence for microbial evolution of RDases. Finally, the capacity for using ORB in a bioremediation and bioaugmentation capacity are discussed. PMID:26973626

Compositional profile of α/β-hydrolase fold proteins in mangrove soil metagenomes: prevalence of epoxide hydrolases and haloalkane dehalogenases in oil-contaminated sites

PubMed Central

Jiménez, Diego Javier; Dini-Andreote, Francisco; Ottoni, Júlia Ronzella; de Oliveira, Valéria Maia; van Elsas, Jan Dirk; Andreote, Fernando Dini

2015-01-01

The occurrence of genes encoding biotechnologically relevant α/β-hydrolases in mangrove soil microbial communities was assessed using data obtained by whole-metagenome sequencing of four mangroves areas, denoted BrMgv01 to BrMgv04, in São Paulo, Brazil. The sequences (215 Mb in total) were filtered based on local amino acid alignments against the Lipase Engineering Database. In total, 5923 unassembled sequences were affiliated with 30 different α/β-hydrolase fold superfamilies. The most abundant predicted proteins encompassed cytosolic hydrolases (abH08; ∼ 23%), microsomal hydrolases (abH09; ∼ 12%) and Moraxella lipase-like proteins (abH04 and abH01; < 5%). Detailed analysis of the genes predicted to encode proteins of the abH08 superfamily revealed a high proportion related to epoxide hydrolases and haloalkane dehalogenases in polluted mangroves BrMgv01-02-03. This suggested selection and putative involvement in local degradation/detoxification of the pollutants. Seven sequences that were annotated as genes for putative epoxide hydrolases and five for putative haloalkane dehalogenases were found in a fosmid library generated from BrMgv02 DNA. The latter enzymes were predicted to belong to Actinobacteria, Deinococcus-Thermus, Planctomycetes and Proteobacteria. Our integrated approach thus identified 12 genes (complete and/or partial) that may encode hitherto undescribed enzymes. The low amino acid identity (< 60%) with already-described genes opens perspectives for both production in an expression host and genetic screening of metagenomes. PMID:25171437

Evaluating iodide recycling inhibition as a novel molecular initiating event for thyroid axis disruption

EPA Science Inventory

The enzyme iodotyrosine deiodinase (dehalogenase, IYD) catalyzes iodide recycling and promotes iodide retention in thyroid follicular cells. Loss of function or chemical inhibition of IYD reduces available iodide for thyroid hormone synthesis, which leads to hormone insufficiency...

Effects of 3-nitro-l-tyrosine on thyroid function in the rat: an experimental model for the dehalogenase defect

PubMed Central

Green, William L.

1971-01-01

The effects on thyroid function of an inhibitor of tyrosine dehalogenase, 3-nitro-L-tyrosine (MNT) have been investigated in rats. In preliminary studies, marked inhibition of iodotyrosine deiodination was demonstrated in rats drinking 8 mM MNT. A series of experiments was then performed in which rats received Remington low iodine diet and 8 mM MNT as drinking fluid. This regimen had the following effects, compared to the effects of a low iodine diet alone: (a) a decrease in serum protein-bound iodine, elevation of serum thyrotropin level, goiter, and growth inhibition all prevented or reversed by iodine supplements: (b) on initiation of MNT, a 2- to 3-fold increase in the rate of release of radioiodine from the thyroid and concomitant urinary excretion of large amounts of organic iodine: and (c) after 2 wk of MNT, a greatly increased rate of thyroidal uptake and release of 131I, an increase in the ratio of monoiodotyrosine-131I to diiodotyrosine-131I in thyroid proteolysates and the appearance of labeled iodotyrosines in serum. Acute administration of MNT intraperitoneally to rats on either an iodine-deficient or iodine-sufficient diet did not inhibit thyroidal uptake of 131I or alter the distribution of 131I among thyroidal iodoamino acids. It is concluded that MNT is an effective inhibitor of iodotyrosine deiodination in vivo, without other important actions on thyroid function. Thus, MNT treatment affords a model for the human dehalogenase defect. By provoking iodotyrosine secretion and consequent urinary loss of iodine, MNT can exaggerate the effects of a low iodine intake, producing goitrous hypothyroidism despite a rapid rate of iodine turnover in the thyroid. Images PMID:5129302

Degradation of 1,2-dichloroethane by Ancylobacter aquaticus and other facultative methylotrophs.

PubMed Central

van den Wijngaard, A J; van der Kamp, K W; van der Ploeg, J; Pries, F; Kazemier, B; Janssen, D B

1992-01-01

Cultures of the newly isolated bacterial strains AD20, AD25, and AD27, identified as strains of Ancylobacter aquaticus, were capable of growth on 1,2-dichloroethane (DCE) as the sole carbon and energy source. These strains, as well as two other new DCE utilizers, were facultative methylotrophs and were also able to grow on 2-chloroethanol, chloroacetate, and 2-chloropropionate. In all strains tested, DCE was degraded by initial hydrolytic dehalogenation to 2-chloroethanol, followed by oxidation by a phenazine methosulfate-dependent alcohol dehydrogenase and an NAD-dependent aldehyde dehydrogenase. The resulting chloroacetic acid was converted to glycolate by chloroacetate dehalogenase. The alcohol dehydrogenase was induced during growth on methanol or DCE in strain AD20, but no activity was found during growth on glucose. However, in strain AD25 the enzyme was synthesized to a higher level during growth on glucose than on methanol, and it reached levels of around 2 U/mg of protein in late-exponential-phase cultures growing on glucose. The haloalkane dehalogenase was constitutively produced in all strains tested, but strain AD25 synthesized the enzyme at a level of 30 to 40% of the total cellular protein, which is much higher than that found in other DCE degraders. The nucleotide sequences of the haloalkane dehalogenase (dhlA) genes of strains AD20 and AD25 were the same as the sequence of dhlA from Xanthobacter autotrophicus GJ10 and GJ11. Hybridization experiments showed that the dhlA genes of six different DCE utilizers were all located on an 8.3-kb EcoRI restriction fragment, indicating that the organisms may have obtained the dhlA gene by horizontal gene transmission. Images PMID:1575500

Compositional profile of α / β-hydrolase fold proteins in mangrove soil metagenomes: prevalence of epoxide hydrolases and haloalkane dehalogenases in oil-contaminated sites.

PubMed

Jiménez, Diego Javier; Dini-Andreote, Francisco; Ottoni, Júlia Ronzella; de Oliveira, Valéria Maia; van Elsas, Jan Dirk; Andreote, Fernando Dini

2015-05-01

The occurrence of genes encoding biotechnologically relevant α/β-hydrolases in mangrove soil microbial communities was assessed using data obtained by whole-metagenome sequencing of four mangroves areas, denoted BrMgv01 to BrMgv04, in São Paulo, Brazil. The sequences (215 Mb in total) were filtered based on local amino acid alignments against the Lipase Engineering Database. In total, 5923 unassembled sequences were affiliated with 30 different α/β-hydrolase fold superfamilies. The most abundant predicted proteins encompassed cytosolic hydrolases (abH08; ∼ 23%), microsomal hydrolases (abH09; ∼ 12%) and Moraxella lipase-like proteins (abH04 and abH01; < 5%). Detailed analysis of the genes predicted to encode proteins of the abH08 superfamily revealed a high proportion related to epoxide hydrolases and haloalkane dehalogenases in polluted mangroves BrMgv01-02-03. This suggested selection and putative involvement in local degradation/detoxification of the pollutants. Seven sequences that were annotated as genes for putative epoxide hydrolases and five for putative haloalkane dehalogenases were found in a fosmid library generated from BrMgv02 DNA. The latter enzymes were predicted to belong to Actinobacteria, Deinococcus-Thermus, Planctomycetes and Proteobacteria. Our integrated approach thus identified 12 genes (complete and/or partial) that may encode hitherto undescribed enzymes. The low amino acid identity (< 60%) with already-described genes opens perspectives for both production in an expression host and genetic screening of metagenomes. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

A tiered approach to evaluate an iodine recycling inhibition adverse outcome pathway (AOP) in amphibians

EPA Science Inventory

The enzyme iodotyrosine deiodinase (dehalogenase, IYD) catalyzes iodide recycling and promotes iodide retention in thyroid follicular cells. Loss of function or chemical inhibition of IYD reduces thyroid hormone synthesis, which leads to insufficiency in tissues and subsequent ne...

Diverse Reductive Dehalogenases Are Associated with Clostridiales-Enriched Microcosms Dechlorinating 1,2-Dichloroethane

PubMed Central

Merlino, Giuseppe; Marzorati, Massimo; Rizzi, Aurora; Lavazza, Davide; de Ferra, Francesca; Carpani, Giovanna

2015-01-01

The achievement of successful biostimulation of active microbiomes for the cleanup of a polluted site is strictly dependent on the knowledge of the key microorganisms equipped with the relevant catabolic genes responsible for the degradation process. In this work, we present the characterization of the bacterial community developed in anaerobic microcosms after biostimulation with the electron donor lactate of groundwater polluted with 1,2-dichloroethane (1,2-DCA). Through a multilevel analysis, we have assessed (i) the structural analysis of the bacterial community; (ii) the identification of putative dehalorespiring bacteria; (iii) the characterization of functional genes encoding for putative 1,2-DCA reductive dehalogenases (RDs). Following the biostimulation treatment, the structure of the bacterial community underwent a notable change of the main phylotypes, with the enrichment of representatives of the order Clostridiales. Through PCR targeting conserved regions within known RD genes, four novel variants of RDs previously associated with the reductive dechlorination of 1,2-DCA were identified in the metagenome of the Clostridiales-dominated bacterial community. PMID:26273600

Crystallization and preliminary X-ray diffraction analysis of the wild-type haloalkane dehalogenase DhaA and its variant DhaA13 complexed with different ligands.

PubMed

Stsiapanava, Alena; Chaloupkova, Radka; Fortova, Andrea; Brynda, Jiri; Weiss, Manfred S; Damborsky, Jiri; Smatanova, Ivana Kuta

2011-02-01

Haloalkane dehalogenases make up an important class of hydrolytic enzymes which catalyse the cleavage of carbon-halogen bonds in halogenated aliphatic compounds. There is growing interest in these enzymes owing to their potential use in environmental and industrial applications. The haloalkane dehalogenase DhaA from Rhodococcus rhodochrous NCIMB 13064 can slowly detoxify the industrial pollutant 1,2,3-trichloropropane (TCP). Structural analysis of this enzyme complexed with target ligands was conducted in order to obtain detailed information about the structural limitations of its catalytic properties. In this study, the crystallization and preliminary X-ray analysis of complexes of wild-type DhaA with 2-propanol and with TCP and of complexes of the catalytically inactive variant DhaA13 with the dye coumarin and with TCP are described. The crystals of wild-type DhaA were plate-shaped and belonged to the triclinic space group P1, while the variant DhaA13 can form prism-shaped crystals belonging to the orthorhombic space group P2(1)2(1)2(1) as well as plate-shaped crystals belonging to the triclinic space group P1. Diffraction data for crystals of wild-type DhaA grown from crystallization solutions with different concentrations of 2-propanol were collected to 1.70 and 1.26 Å resolution, respectively. A prism-shaped crystal of DhaA13 complexed with TCP and a plate-shaped crystal of the same variant complexed with the dye coumarin diffracted X-rays to 1.60 and 1.33 Å resolution, respectively. A crystal of wild-type DhaA and a plate-shaped crystal of DhaA13, both complexed with TCP, diffracted to atomic resolutions of 1.04 and 0.97 Å, respectively.

Inactivation of Cg10062, a cis-3-chloroacrylic acid dehalogenase homologue in Corynebacterium glutamicum, by (R)- and (S)-oxirane-2-carboxylate: analysis and implications.

PubMed

Robertson, Brooklyn A; Johnson, William H; Lo, Herng-Hsiang; Whitman, Christian P

2008-08-19

( R)- and ( S)-oxirane-2-carboxylate were determined to be active site-directed irreversible inhibitors of the cis-3-chloroacrylic acid dehalogenase ( cis-CaaD) homologue Cg10062 found in Corynebacterium glutamicum. Kinetic analysis indicates that the ( R) enantiomer binds more tightly and is the more potent inhibitor, likely reflecting more favorable interactions with active site residues. Pro-1 is the sole site of covalent modification by the ( R) and ( S) enantiomers. Pro-1, Arg-70, Arg-73, and Glu-114, previously identified as catalytic residues in Cg10062, have also been implicated in the inactivation mechanism. Pro-1, Arg-70, and Arg-73 are essential residues for the process as indicated by the observation that the enzymes with the corresponding alanine mutations are not covalently modified by either enantiomer. The E114Q mutant slows covalent modification of Cg10062 but does not prevent it. The results are comparable to those found for the irreversible inactivation of cis-CaaD by ( R)-oxirane-2-carboxylate with two important distinctions: the alkylation of cis-CaaD is stereospecific, and Glu-114 does not take part in the cis-CaaD inactivation mechanism. Cg10062 exhibits low-level cis-CaaD and trans-3-chloroacrylic acid dehalogenase (CaaD) activities, with the cis-CaaD activity predominating. Hence, the preference of Cg10062 for the cis isomer correlates with the observation that the ( R) enantiomer is the more potent inactivator. Moreover, the factors responsible for the relaxed substrate specificity of Cg10062 may account for the stereoselective inactivation by the enantiomeric epoxides. Delineation of these factors would provide a more complete picture of the substrate specificity determinants for cis-CaaD. This study represents an important step toward this goal by setting the stage for a crystallographic analysis of inactivated Cg10062.

The X-ray Crystallographic Structure and Activity Analysis of a Pseudomonas-Specific Subfamily of the HAD Enzyme Superfamily Evidences a Novel Biochemical Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peisach,E.; Wang, L.; Burroughs, A.

2008-01-01

The haloacid dehalogenase (HAD) superfamily is a large family of proteins dominated by phosphotransferases. Thirty-three sequence families within the HAD superfamily (HADSF) have been identified to assist in function assignment. One such family includes the enzyme phosphoacetaldehyde hydrolase (phosphonatase). Phosphonatase possesses the conserved Rossmanniod core domain and a C1-type cap domain. Other members of this family do not possess a cap domain and because the cap domain of phosphonatase plays an important role in active site desolvation and catalysis, the function of the capless family members must be unique. A representative of the capless subfamily, PSPTO{_}2114, from the plant pathogenmore » Pseudomonas syringae, was targeted for catalytic activity and structure analyses. The X-ray structure of PSPTO{_}2114 reveals a capless homodimer that conserves some but not all of the intersubunit contacts contributed by the core domains of the phosphonatase homodimer. The region of the PSPTO{_}2114 that corresponds to the catalytic scaffold of phosphonatase (and other HAD phosphotransfereases) positions amino acid residues that are ill suited for Mg+2 cofactor binding and mediation of phosphoryl group transfer between donor and acceptor substrates. The absence of phosphotransferase activity in PSPTO{_}2114 was confirmed by kinetic assays. To explore PSPTO{_}2114 function, the conservation of sequence motifs extending outside of the HADSF catalytic scaffold was examined. The stringently conserved residues among PSPTO{_}2114 homologs were mapped onto the PSPTO{_}2114 three-dimensional structure to identify a surface region unique to the family members that do not possess a cap domain. The hypothesis that this region is used in protein-protein recognition is explored to define, for the first time, HADSF proteins which have acquired a function other than that of a catalyst. Proteins 2008.« less

Development of a Dehalogenase-Based Protein Fusion Tag Capable of Rapid, Selective and Covalent Attachment to Customizable Ligands

PubMed Central

Encell, Lance P; Friedman Ohana, Rachel; Zimmerman, Kris; Otto, Paul; Vidugiris, Gediminas; Wood, Monika G; Los, Georgyi V; McDougall, Mark G; Zimprich, Chad; Karassina, Natasha; Learish, Randall D; Hurst, Robin; Hartnett, James; Wheeler, Sarah; Stecha, Pete; English, Jami; Zhao, Kate; Mendez, Jacqui; Benink, Hélène A; Murphy, Nancy; Daniels, Danette L; Slater, Michael R; Urh, Marjeta; Darzins, Aldis; Klaubert, Dieter H; Bulleit, Robert F; Wood, Keith V

2012-01-01

Our fundamental understanding of proteins and their biological significance has been enhanced by genetic fusion tags, as they provide a convenient method for introducing unique properties to proteins so that they can be examinedin isolation. Commonly used tags satisfy many of the requirements for applications relating to the detection and isolation of proteins from complex samples. However, their utility at low concentration becomes compromised if the binding affinity for a detection or capture reagent is not adequate to produce a stable interaction. Here, we describe HaloTag® (HT7), a genetic fusion tag based on a modified haloalkane dehalogenase designed and engineered to overcome the limitation of affinity tags by forming a high affinity, covalent attachment to a binding ligand. HT7 and its ligand have additional desirable features. The tag is relatively small, monomeric, and structurally compatible with fusion partners, while the ligand is specific, chemically simple, and amenable to modular synthetic design. Taken together, the design features and molecular evolution of HT7 have resulted in a superior alternative to common tags for the overexpression, detection, and isolation of target proteins. PMID:23248739

Identification and environmental distribution of dcpA encoding the 1,2-dichloropropane-to-propene reductive dehalogenase in organohalide-respiring Chloroflexi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padilla-Crespo, Elizabeth; Yan, Jun; Swift, Cynthia M

2014-01-01

Dehalococcoides mccartyi (Dhc) strains KS and RC grow with 1,2-dichloropropane (1,2-D) as an electron acceptor in enrichment cultures derived from hydrocarbon-contaminated and pristine river sediments, respectively. Transcription, expression, enzymatic and PCR analyses implicated the reductive dehalogenase gene dcpA in 1,2-D dichloroelimination to propene and inorganic chloride. Quantitative real-time PCR (qPCR) analyses demonstrated Dhc cell increase during growth with 1,2-D and suggested that both Dhc strains carried a single dcpA gene copy per genome. Dhc strain RC and strain KS produced 1.8 0.1 x 107 and 1.4 0.5 x 107 cells per mole of propene formed, respectively. The dcpA gene wasmore » identified in 1,2-D-to-propene-dechlorinating microcosms established with sediment samples collected from different geographical locations in Europe and North and South America. Clone library analysis revealed two distinct dcpA phylogenetic clusters, both of which the dcpA gene-targeted qPCR assay captured, suggesting the qPCR assay is useful for site assessment and bioremediation monitoring at 1,2-D-contaminated sites.« less

Pre-Steady State Kinetic Analysis of cis-3-Chloroacrylic Acid Dehalogenase: Analysis and Implications†

PubMed Central

Robertson, Brooklyn A.; Schroeder, Gottfried K.; Jin, Zhinan; Johnson, Kenneth A.; Whitman, Christian P.

2009-01-01

Isomer-specific 3-chloroacrylic acid dehalogenases catalyze the hydrolytic dehalogenation of the cis- and trans-isomers of 3-chloroacrylate to yield malonate semialdehyde. These reactions represent key steps in the degradation of the nematocide, 1,3-dichloropropene. The kinetic mechanism of cis-3-chloroacrylic acid dehalogenase (cis-CaaD) has now been examined using stopped-flow and chemical-quench techniques. Stopped-flow analysis of the reaction, following the fluorescence of an active site tryptophan, is consistent with a minimal three-step model involving substrate binding, chemistry, and product release. Chemical quench experiments show burst kinetics, indicating that product release is at least partially rate limiting. Global fitting of all of the kinetic results by simulation is best accommodated by a four-step mechanism. In the final kinetic model, the enzyme binds substrate and isomerizes to an alternate fluorescent form, chemistry occurs, and is followed by the ordered release of two products, with the release of the first product as the rate-limiting step. Bromide ion is a competitive inhibitor of the reaction indicating that it binds to the free enzyme rather than to the enzyme with one product still bound. This observation suggests that malonate semialdehyde is the first product released by the enzyme (rate limiting), followed by halide. A comparison of the unliganded cis-CaaD crystal structure with that of an inactivated cis-CaaD where the prolyl nitrogen of Pro-1 is covalently attached to (R)-2-hydroxypropanoate provides a possible explanation for the isomerization step. The structure of the covalently modified enzyme shows that a 7-residue loop comprised of residues 32-38 is closed down on the active site cavity where the backbone amides of two residues (Phe-37 and Leu-38) interact with the carboxylate group of the adduct. In the unliganded form, the same loop points away from the active site cavity. Similarly, substrate binding may cause this loop to close down on the active site and sequester the reaction from the external environment. PMID:19856961

Kinetics of Bacterial Growth on Chlorinated Aliphatic Compounds

PubMed Central

van den Wijngaard, Arjan J.; Wind, Richèle D.; Janssen, Dick B.

1993-01-01

With the pure bacterial cultures Ancylobacter aquaticus AD20 and AD25, Xanthobacter autotrophicus GJ10, and Pseudomonas sp. strain AD1, Monod kinetics was observed during growth in chemostat cultures on 1,2-dichloroethane (AD20, AD25, and GJ10), 2-chloroethanol (AD20 and GJ10), and 1,3-dichloro-2-propanol (AD1). Both the Michaelis-Menten constants (Km) of the first catabolic (dehalogenating) enzyme and the Monod half-saturation constants (Ks) followed the order 2-chloroethanol, 1,3-dichloro-2-propanol, epichlorohydrin, and 1,2-dichloroethane. The Ks values of strains GJ10, AD20, and AD25 for 1,2-dichloroethane were 260, 222, and 24 μM, respectively. The low Ks value of strain AD25 was correlated with a higher haloalkane dehalogenase content of this bacterium. The growth rates of strains AD20 and GJ10 in continuous cultures on 1,2-dichloroethane were higher than the rates predicted from the kinetics of the haloalkane dehalogenase and the concentration of the enzyme in the cells. The results indicate that the efficiency of chlorinated compound removal is indeed influenced by the kinetic properties and cellular content of the first catabolic enzyme. The cell envelope did not seem to act as a barrier for permeation of 1,2-dichloroethane. PMID:16348981

Production of chlorothalonil hydrolytic dehalogenase from agro-industrial wastewater and its application in raw food cleaning.

PubMed

He, Qin; Xu, Xi-Hui; Zhang, Fan; Tai, Yu-Kai; Luo, Yan-Fei; He, Jian; Hong, Qing; Jiang, Jian-Dong; Yan, Xin

2017-06-01

To reduce the fermentation cost for industrialization of chlorothalonil hydrolytic dehalogenase (Chd), agro-industrial wastewaters including molasses, corn steep liquor (CSL) and fermentation wastewater were used to substitute for expensive carbon and nitrogen sources and fresh water for lab preparation. The results showed that molasses and CSL could replace 5% carbon source and 100% organic nitrogen source respectively to maintain the same fermentation level. Re-fermentation from raffinate of ultra-filtered fermentation wastewater could achieve 61.03% of initial Chd activity and reach 96.39% activity when cultured in a mixture of raffinate and 50% of original medium constituent. Typical raw foods were chosen to evaluate the chlorothalonil removal ability of Chd. After Chd treatment for 2 h at room temperature, 97.40 and 75.55% of 30 mg kg -1 chlorothalonil on cherry tomato and strawberry respectively and 60.29% of 50 mg kg -1 chlorothalonil on Chinese cabbage were removed. Furthermore, the residual activity of the enzyme remained at 78-82% after treatment, suggesting its potential for reuse. This study proved the cost-feasibility of large-scale production of Chd from agro-industrial wastewater and demonstrated the potential of Chd in raw food cleaning. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Chloride-associated adaptive response in aerobic methylotrophic dichloromethane-utilising bacteria.

PubMed

Torgonskaya, Maria L; Doronina, Nina V; Hourcade, Edith; Trotsenko, Yuri A; Vuilleumier, Stéphane

2011-06-01

Aerobic methylotrophic bacteria able to grow with dichloromethane (DCM) as the sole carbon and energy source possess a specific glutathione S-transferase, DCM dehalogenase, which transforms DCM to formaldehyde, used for biomass and energy production, and hydrochloric acid, which is excreted. Evidence is presented for chloride-specific responses for three DCM-degrading bacteria, Methylobacterium extorquens DM4, Methylopila helvetica DM6 and Albibacter methylovorans DM10. Chloride release into the medium was inhibited by sodium azide and m -chlorophenylhydrazone, suggesting an energy-dependent process. In contrast, only nigericin affected chloride excretion in Mb. extorquens DM4 and Mp. helvetica DM6, while valinomycin had the same effect in A. methylovorans DM10 only. Chloride ions stimulated DCM-dependent induction of DCM dehalogenase expression for Mp. helvetica DM6 and A. methylovorans DM10, and shortened the time for onset of chloride release into the medium. Striking chloride-containing structures were observed by electron microscopy and X-ray microanalysis on the cell surface of Mp. helvetica DM6 and A. methylovorans DM10 during growth with DCM, and with methanol in medium supplemented with sodium chloride. Taken together, these data suggest the existence of both general and specific chloride-associated adaptations in aerobic DCM-degrading bacteria. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and application of a rapid, user-friendly, and inexpensive method to detect Dehalococcoides sp. reductive dehalogenase genes from groundwater.

PubMed

Kanitkar, Yogendra H; Stedtfeld, Robert D; Hatzinger, Paul B; Hashsham, Syed A; Cupples, Alison M

2017-06-01

TaqMan probe-based quantitative polymerase chain reaction (qPCR) specific to the biomarker reductive dehalogenase (RDase) genes is a widely accepted molecular biological tool (MBT) for determining the abundance of Dehalococcoides sp. in groundwater samples from chlorinated solvent-contaminated sites. However, there are significant costs associated with this MBT. In this study, we describe an approach that requires only low-cost laboratory equipment (a bench top centrifuge and a water bath) and requires less time and resources compared to qPCR. The method involves the concentration of biomass from groundwater, without DNA extraction, and loop-mediated isothermal amplification (LAMP) of the cell templates. The amplification products are detected by a simple visual color change (orange/green). The detection limits of the assay were determined using groundwater from a contaminated site. In addition, the assay was tested with groundwater from three additional contaminated sites. The final approach to detect RDase genes, without DNA extraction or a thermal cycler, was successful to 1.8 × 10 5  gene copies per L for vcrA and 1.3 × 10 5  gene copies per L for tceA. Both values are below the threshold recommended for effective in situ dechlorination.

PCB dechlorination hotspots and reductive dehalogenase genes in sediments from a contaminated wastewater lagoon.

PubMed

Mattes, Timothy E; Ewald, Jessica M; Liang, Yi; Martinez, Andres; Awad, Andrew; Richards, Patrick; Hornbuckle, Keri C; Schnoor, Jerald L

2017-08-12

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that are distributed worldwide. Although industrial PCB production has stopped, legacy contamination can be traced to several different commercial mixtures (e.g., Aroclors in the USA). Despite their persistence, PCBs are subject to naturally occurring biodegradation processes, although the microbes and enzymes involved are poorly understood. The biodegradation potential of PCB-contaminated sediments in a wastewater lagoon located in Virginia (USA) was studied. Total PCB concentrations in sediments ranged from 6.34 to 12,700 mg/kg. PCB congener profiles in sediment sample were similar to Aroclor 1248; however, PCB congener profiles at several locations showed evidence of dechlorination. The sediment microbial community structure varied among samples but was dominated by Proteobacteria and Firmicutes. The relative abundance of putative dechlorinating Chloroflexi (including Dehalococcoides sp.) was 0.01-0.19% among the sediment samples, with Dehalococcoides sp. representing 0.6-14.8% of this group. Other possible PCB dechlorinators present included the Clostridia and the Geobacteraceae. A PCR survey for potential PCB reductive dehalogenase genes (RDases) yielded 11 sequences related to RDase genes in PCB-respiring Dehalococcoides mccartyi strain CG5 and PCB-dechlorinating D. mccartyi strain CBDB1. This is the first study to retrieve potential PCB RDase genes from unenriched PCB-contaminated sediments.

Isolation and Identification of Sodium Fluoroacetate Degrading Bacteria from Caprine Rumen in Brazil

PubMed Central

Camboim, Expedito K. A.; Almeida, Arthur P.; Tadra-Sfeir, Michelle Z.; Junior, Felício G.; Andrade, Paulo P.; McSweeney, Chris S.; Melo, Marcia A.; Riet-Correa, Franklin

2012-01-01

The objective of this paper was to report the isolation of two fluoroacetate degrading bacteria from the rumen of goats. The animals were adult goats, males, crossbred, with rumen fistula, fed with hay, and native pasture. The rumen fluid was obtained through the rumen fistula and immediately was inoculated 100 μL in mineral medium added with 20 mmol L−1 sodium fluoroacetate (SF), incubated at 39°C in an orbital shaker. Pseudomonas fluorescens (strain DSM 8341) was used as positive control for fluoroacetate dehalogenase activity. Two isolates were identified by 16S rRNA gene sequencing as Pigmentiphaga kullae (ECPB08) and Ancylobacter dichloromethanicus (ECPB09). These bacteria degraded sodium fluoroacetate, releasing 20 mmol L−1 of fluoride ion after 32 hours of incubation in Brunner medium containing 20 mmol L−1 of SF. There are no previous reports of fluoroacetate dehalogenase activity for P. kullae and A. dichloromethanicus. Control measures to prevent plant intoxication, including use of fences, herbicides, or other methods of eliminating poisonous plants, have been unsuccessful to avoid poisoning by fluoroacetate containing plants in Brazil. In this way, P. kullae and A. dichloromethanicus may be used to colonize the rumen of susceptible animals to avoid intoxication by fluoroacetate containing plants. PMID:22919294

The restricted metabolism of the obligate organohalide respiring bacterium Dehalobacter restrictus: lessons from tiered functional genomics

PubMed Central

Rupakula, Aamani; Kruse, Thomas; Boeren, Sjef; Holliger, Christof; Smidt, Hauke; Maillard, Julien

2013-01-01

Dehalobacter restrictus strain PER-K23 is an obligate organohalide respiring bacterium, which displays extremely narrow metabolic capabilities. It grows only via coupling energy conservation to anaerobic respiration of tetra- and trichloroethene with hydrogen as sole electron donor. Dehalobacter restrictus represents the paradigmatic member of the genus Dehalobacter, which in recent years has turned out to be a major player in the bioremediation of an increasing number of organohalides, both in situ and in laboratory studies. The recent elucidation of the D. restrictus genome revealed a rather elaborate genome with predicted pathways that were not suspected from its restricted metabolism, such as a complete corrinoid biosynthetic pathway, the Wood–Ljungdahl (WL) pathway for CO2 fixation, abundant transcriptional regulators and several types of hydrogenases. However, one important feature of the genome is the presence of 25 reductive dehalogenase genes, from which so far only one, pceA, has been characterized on genetic and biochemical levels. This study describes a multi-level functional genomics approach on D. restrictus across three different growth phases. A global proteomic analysis allowed consideration of general metabolic pathways relevant to organohalide respiration, whereas the dedicated genomic and transcriptomic analysis focused on the diversity, composition and expression of genes associated with reductive dehalogenases. PMID:23479754

Mechanism of enhanced conversion of 1,2,3-trichloropropane by mutant haloalkane dehalogenase revealed by molecular modeling

NASA Astrophysics Data System (ADS)

Banáš, Pavel; Otyepka, Michal; Jeřábek, Petr; Petřek, Martin; Damborský, Jiří

2006-06-01

1,2,3-Trichloropropane (TCP) is a highly toxic, recalcitrant byproduct of epichlorohydrin manufacture. Haloalkane dehalogenase (DhaA) from Rhodococcus sp. hydrolyses the carbon-halogen bond in various halogenated compounds including TCP, but with low efficiency ( k cat/ K m = 36 s-1 M-1). A Cys176Tyr-DhaA mutant with a threefold higher catalytic efficiency for TCP dehalogenation has been previously obtained by error-prone PCR. We have used molecular simulations and quantum mechanical calculations to elucidate the molecular mechanisms involved in the improved catalysis of the mutant, and enantioselectivity of DhaA toward TCP. The Cys176Tyr mutation modifies the protein access and export routes. Substitution of the Cys residue by the bulkier Tyr narrows the upper tunnel, making the second tunnel "slot" the preferred route. TCP can adopt two major orientations in the DhaA enzyme, in one of which the halide-stabilizing residue Asn41 forms a hydrogen bond with the terminal halogen atom of the TCP molecule, while in the other it bonds with the central halogen atom. The differences in these binding patterns explain the preferential formation of the ( R)- over the ( S)-enantiomer of 2,3-dichloropropane-1-ol in the reaction catalyzed by the enzyme.

Chloromuconolactone dehalogenase ClcF of actinobacteria.

PubMed

Solyanikova, Inna P; Plotnikova, Elena G; Shumkova, Ekaterina S; Robota, Irina V; Prisyazhnaya, Natalya V; Golovleva, Ludmila A

2014-01-01

This work investigated the distribution of the clcF gene in actinobacteria isolated from different ecotopes. The gene encodes chloromuconolactone dehalogenase (CMLD) ClcF, the enzyme found to date in only one representative of Gram-positive bacteria, Rhodococcus opacus 1CP, adapted to 2-chlorophenol (2CP). Using primers specific to the clcF gene, from the DNA matrix of rhodococcal strains closely related to species Rhodococcus wratislaviensis (P1, P12, P13, P20, G10, KT112, KT723, BO1) we obtained PCR products whose nucleotide sequences were 100% identical to that of the clcF gene from strain R. opacus 1CP. CMLDs isolated from the biomass of strains Rhodococcus spp. G10 and P1 grown on 2CP did not differ by their subunit molecular mass deduced from the known amino acid sequence of the clcF gene from the ClcF of strain R. opacus 1CP. Matrix-assisted laser dissociation/ionization time-of-flight mass spectrometry showed the presence of a peak with m/z 11,194-11,196 Da both in whole cells and in protein solutions with a ClcF activity. Thus, we have first time shown the distribution of ClcF among actinobacteria isolated from geographically distant habitats.

Evidence for 4-chlorobenzoic acid dehalogenation mediated by plasmids related to pSS50.

PubMed Central

Layton, A C; Sanseverino, J; Wallace, W; Corcoran, C; Sayler, G S

1992-01-01

The biodegradation of 4-chlorobiphenyl usually proceeds through the intermediate 4-chlorobenzoate. Few bacterial strains can degrade 4-chlorobiphenyl to 4-chlorobenzoate and 4-chlorobenzoate to CO2. This study demonstrates that the 4-chlorobiphenyl-degrading Alcaligenes sp. strain ALP83 can degrade 4-chlorobenzoate to 4-hydroxybenzoate. The dehalogenase activity is correlated with a 10-kb fragment carried on plasmid pSS70. Images PMID:1539985

Sister Dehalobacter Genomes Reveal Specialization in Organohalide Respiration and Recent Strain Differentiation Likely Driven by Chlorinated Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Shuiquan; Wang, Po Hsiang; Higgins, Steven A.

Here we report that the genomes of two closely related Dehalobacter strains (strain CF and strain DCA) were assembled from the metagenome of an anaerobic enrichment culture that reductively dechlorinates chloroform (CF), 1,1,1-trichloroethane (1,1,1-TCA) and 1,1-dichloroethane (1,1-DCA). The 3.1 Mbp genomes of strain CF (that dechlorinates CF and 1,1,1-TCA) and strain DCA (that dechlorinates 1,1-DCA) each contain 17 putative reductive dehalogenase homologous (rdh) genes. These two genomes were systematically compared to three other available organohalide-respiring Dehalobacter genomes (Dehalobacter restrictus strain PER-K23, Dehalobacter sp. strain E1 and Dehalobacter sp. strain UNSWDHB), and to the genomes of Dehalococcoides mccartyi strain 195 andmore » Desulfitobacterium hafniense strain Y51. This analysis compared 42 different metabolic and physiological categories. The genomes of strains CF and DCA share 90% overall average nucleotide identity and >99.8% identity over a 2.9 Mbp alignment that excludes large insertions, indicating that these genomes differentiated from a close common ancestor. This differentiation was likely driven by selection pressures around two orthologous reductive dehalogenase genes, cfrA and dcrA, that code for the enzymes that reduce CF or 1,1,1-TCA and 1,1-DCA. The many reductive dehalogenase genes found in the five Dehalobacter genomes cluster into two small conserved regions and were often associated with Crp/Fnr transcriptional regulators. Specialization is on-going on a strain-specific basis, as some strains but not others have lost essential genes in the Wood-Ljungdahl (strain E1) and corrinoid biosynthesis pathways (strains E1 and PER-K23). The gene encoding phosphoserine phosphatase, which catalyzes the last step of serine biosynthesis, is missing from all five Dehalobacter genomes, yet D. restrictus can grow without serine, suggesting an alternative or unrecognized biosynthesis route exists. In contrast to D. mccartyi, a complete heme biosynthesis pathway is present in the five Dehalobacter genomes. This pathway corresponds to a newly described alternative heme biosynthesis route first identified in Archaea. Ultimately, this analysis of organohalide-respiring Firmicutes and Chloroflexi reveals profound evolutionary differences despite very similar niche-specific metabolism and function.« less

Sister Dehalobacter Genomes Reveal Specialization in Organohalide Respiration and Recent Strain Differentiation Likely Driven by Chlorinated Substrates

DOE PAGES

Tang, Shuiquan; Wang, Po Hsiang; Higgins, Steven A.; ...

2016-02-12

Here we report that the genomes of two closely related Dehalobacter strains (strain CF and strain DCA) were assembled from the metagenome of an anaerobic enrichment culture that reductively dechlorinates chloroform (CF), 1,1,1-trichloroethane (1,1,1-TCA) and 1,1-dichloroethane (1,1-DCA). The 3.1 Mbp genomes of strain CF (that dechlorinates CF and 1,1,1-TCA) and strain DCA (that dechlorinates 1,1-DCA) each contain 17 putative reductive dehalogenase homologous (rdh) genes. These two genomes were systematically compared to three other available organohalide-respiring Dehalobacter genomes (Dehalobacter restrictus strain PER-K23, Dehalobacter sp. strain E1 and Dehalobacter sp. strain UNSWDHB), and to the genomes of Dehalococcoides mccartyi strain 195 andmore » Desulfitobacterium hafniense strain Y51. This analysis compared 42 different metabolic and physiological categories. The genomes of strains CF and DCA share 90% overall average nucleotide identity and >99.8% identity over a 2.9 Mbp alignment that excludes large insertions, indicating that these genomes differentiated from a close common ancestor. This differentiation was likely driven by selection pressures around two orthologous reductive dehalogenase genes, cfrA and dcrA, that code for the enzymes that reduce CF or 1,1,1-TCA and 1,1-DCA. The many reductive dehalogenase genes found in the five Dehalobacter genomes cluster into two small conserved regions and were often associated with Crp/Fnr transcriptional regulators. Specialization is on-going on a strain-specific basis, as some strains but not others have lost essential genes in the Wood-Ljungdahl (strain E1) and corrinoid biosynthesis pathways (strains E1 and PER-K23). The gene encoding phosphoserine phosphatase, which catalyzes the last step of serine biosynthesis, is missing from all five Dehalobacter genomes, yet D. restrictus can grow without serine, suggesting an alternative or unrecognized biosynthesis route exists. In contrast to D. mccartyi, a complete heme biosynthesis pathway is present in the five Dehalobacter genomes. This pathway corresponds to a newly described alternative heme biosynthesis route first identified in Archaea. Ultimately, this analysis of organohalide-respiring Firmicutes and Chloroflexi reveals profound evolutionary differences despite very similar niche-specific metabolism and function.« less

Imaging Prostate Cancer Microenvironment by Collagen Hybridization

DTIC Science & Technology

2015-10-01

group and the adjacent bulky dye . In an effort to move away from radioiodine and what appears to be in vivo dehalogenase activity, we next...undesirable and will prompt the pursuit of dye -free CMP analogs as the dye is targeting this excretion pathway. We finished probing the library of PCa...integrity of the dye and/or the nitrobenzoyl photo cage group. Deviations away from pH 6-8 and heating are to be avoided. Our current strategy of using

Draft Genome Sequence of a Hexachlorocyclohexane-Degrading Bacterium, Sphingobium baderi Strain LL03T

PubMed Central

Kaur, Jasvinder; Verma, Helianthous; Tripathi, Charu; Khurana, J. P.

2013-01-01

Sphingobium baderi strain LL03T was isolated from hexachlorocyclohexane (HCH)-contaminated soil from Spolana, Czech Republic. Strain LL03T is a mutant that is deficient in linB and linC (genes that encode hexachlorocyclohexane haloalkane dehalogenase and dehydrogenase, respectively). The draft genome sequence of LL03T (~4.85 Mb) consists of 92 contigs and 4,914 coding sequences, with a G+C content of 63.5%. PMID:24051322

Coexistence of two distinct Sulfurospirillum populations respiring tetrachloroethene-genomic and kinetic considerations.

PubMed

Buttet, Géraldine Florence; Murray, Alexandra Marie; Goris, Tobias; Burion, Mélissa; Jin, Biao; Rolle, Massimo; Holliger, Christof; Maillard, Julien

2018-05-01

Two anaerobic bacterial consortia, each harboring a distinct Sulfurospirillum population, were derived from a 10 year old consortium, SL2, previously characterized for the stepwise dechlorination of tetrachloroethene (PCE) to cis-dichloroethene (cis-DCE) via accumulation of trichloroethene (TCE). Population SL2-1 dechlorinated PCE to TCE exclusively, while SL2-2 produced cis-DCE from PCE without substantial TCE accumulation. The reasons explaining the long-term coexistence of the populations were investigated. Genome sequencing revealed a novel Sulfurospirillum species, designated 'Candidatus Sulfurospirillum diekertiae', whose genome differed significantly from other Sulfurospirillum spp. (78%-83% ANI). Genome-wise, SL2-1 and SL2-2 populations are almost identical, but differences in their tetrachloroethene reductive dehalogenase sequences explain the distinct dechlorination patterns. An extended series of batch cultures were performed at PCE concentrations of 2-200 μM. A model was developed to determine their dechlorination kinetic parameters. The affinity constant and maximal growth rate differ between the populations: the affinity is 6- to 8-fold higher and the growth rate 5-fold lower for SL2-1 than SL2-2. Mixed cultivation of the enriched populations at 6 and 30 μM PCE showed that a low PCE concentration could be the driving force for both functional diversity of reductive dehalogenases and niche specialization of organohalide-respiring bacteria with overlapping substrate ranges.

A computational study of the dechlorination of β-hexachlorocyclohexane (β-HCH) catalyzed by the haloalkane dehalogenase LinB.

PubMed

Manna, Rabindra Nath; Dybala-Defratyka, Agnieszka

2014-11-15

LinB, a haloalkane dehalogenase from Sphingomonas paucimobilis UT26, is known to metabolize halohydrocarbons to halide ions and the respective alcohols. Its broad substrate specificity allowed its consideration for bioremediation. Herein, we have shown its catalytic action toward β-hexachlorocyclohexane (β-HCH) - an example of large-size substrates that can be accommodated in its active site. We have analyzed the capability of combined QM/MM schemes to describe in detail the SN2 dechlorination reaction between β-HCH and Asp108 in the active site of LinB. Free energy surfaces have been calculated using one and two dimensional potentials of mean force (PMF) obtained at the PM3/MM (MM=amberff99SB, TIP3P) level of theory. The overestimated energetic barriers by the PM3 Hamiltonian were corrected using a DFT functional (M06-2X). The resulted activation energies (16 and 19 kcal mol(-1) from 1D and 2D-PMF profiles, respectively) for the dechlorination reaction of β-HCH in the active site of LinB enzyme are in qualitative agreement with the experimentally determined value of 17 kcal mol(-1). The binding of β-HCH to the active site of LinB has been compared to the binding of smaller 1-chlorobutane (1-CB) and larger δ-hexabromocyclododecane (δ-HBCD). Copyright © 2014 Elsevier Inc. All rights reserved.

Functional Diversity of Haloacid Dehalogenase Superfamily Phosphatases from Saccharomyces cerevisiae: BIOCHEMICAL, STRUCTURAL, AND EVOLUTIONARY INSIGHTS.

PubMed

Kuznetsova, Ekaterina; Nocek, Boguslaw; Brown, Greg; Makarova, Kira S; Flick, Robert; Wolf, Yuri I; Khusnutdinova, Anna; Evdokimova, Elena; Jin, Ke; Tan, Kemin; Hanson, Andrew D; Hasnain, Ghulam; Zallot, Rémi; de Crécy-Lagard, Valérie; Babu, Mohan; Savchenko, Alexei; Joachimiak, Andrzej; Edwards, Aled M; Koonin, Eugene V; Yakunin, Alexander F

2015-07-24

The haloacid dehalogenase (HAD)-like enzymes comprise a large superfamily of phosphohydrolases present in all organisms. The Saccharomyces cerevisiae genome encodes at least 19 soluble HADs, including 10 uncharacterized proteins. Here, we biochemically characterized 13 yeast phosphatases from the HAD superfamily, which includes both specific and promiscuous enzymes active against various phosphorylated metabolites and peptides with several HADs implicated in detoxification of phosphorylated compounds and pseudouridine. The crystal structures of four yeast HADs provided insight into their active sites, whereas the structure of the YKR070W dimer in complex with substrate revealed a composite substrate-binding site. Although the S. cerevisiae and Escherichia coli HADs share low sequence similarities, the comparison of their substrate profiles revealed seven phosphatases with common preferred substrates. The cluster of secondary substrates supporting significant activity of both S. cerevisiae and E. coli HADs includes 28 common metabolites that appear to represent the pool of potential activities for the evolution of novel HAD phosphatases. Evolution of novel substrate specificities of HAD phosphatases shows no strict correlation with sequence divergence. Thus, evolution of the HAD superfamily combines the conservation of the overall substrate pool and the substrate profiles of some enzymes with remarkable biochemical and structural flexibility of other superfamily members. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Expansion of access tunnels and active-site cavities influence activity of haloalkane dehalogenases in organic cosolvents.

PubMed

Stepankova, Veronika; Khabiri, Morteza; Brezovsky, Jan; Pavelka, Antonin; Sykora, Jan; Amaro, Mariana; Minofar, Babak; Prokop, Zbynek; Hof, Martin; Ettrich, Rudiger; Chaloupkova, Radka; Damborsky, Jiri

2013-05-10

The use of enzymes for biocatalysis can be significantly enhanced by using organic cosolvents in the reaction mixtures. Selection of the cosolvent type and concentration range for an enzymatic reaction is challenging and requires extensive empirical testing. An understanding of protein-solvent interaction could provide a theoretical framework for rationalising the selection process. Here, the behaviour of three model enzymes (haloalkane dehalogenases) was investigated in the presence of three representative organic cosolvents (acetone, formamide, and isopropanol). Steady-state kinetics assays, molecular dynamics simulations, and time-resolved fluorescence spectroscopy were used to elucidate the molecular mechanisms of enzyme-solvent interactions. Cosolvent molecules entered the enzymes' access tunnels and active sites, enlarged their volumes with no change in overall protein structure, but surprisingly did not act as competitive inhibitors. At low concentrations, the cosolvents either enhanced catalysis by lowering K(0.5) and increasing k(cat), or caused enzyme inactivation by promoting substrate inhibition and decreasing k(cat). The induced activation and inhibition of the enzymes correlated with expansion of the active-site pockets and their occupancy by cosolvent molecules. The study demonstrates that quantitative analysis of the proportions of the access tunnels and active-sites occupied by organic solvent molecules provides the valuable information for rational selection of appropriate protein-solvent pair and effective cosolvent concentration. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Changes of chlorine isotope composition characterize bacterial dehalogenation of dichloromethane].

PubMed

Ziakun, A M; Firsova, Iu E; Torgonskaia, M L; Doronina, N V; Trotsenko, Iu A

2007-01-01

Fractionation of dichloromethane (DCM) molecules with different chlorine isotopes by aerobic methylobacteria Methylobacterium dichloromethanicum DM4 and Albibacter nethylovorans DM10; cell-free extract of strain DM4; and transconjugant Methylobacterium evtorquens Al1/pME 8220, expressing the dcmA gene for DCM dehalogenase but unable to grow on DCM, was studied. Kinetic indices of DCM isotopomers for chlorine during bacterial dehalogenation and diffusion were compared. A two-step model is proposed, which suggests diffusional DCM transport to bacterial cells.

Lipin 2 binds phosphatidic acid by the electrostatic hydrogen bond switch mechanism independent of phosphorylation.

PubMed

Eaton, James M; Takkellapati, Sankeerth; Lawrence, Robert T; McQueeney, Kelley E; Boroda, Salome; Mullins, Garrett R; Sherwood, Samantha G; Finck, Brian N; Villén, Judit; Harris, Thurl E

2014-06-27

Lipin 2 is a phosphatidic acid phosphatase (PAP) responsible for the penultimate step of triglyceride synthesis and dephosphorylation of phosphatidic acid (PA) to generate diacylglycerol. The lipin family of PA phosphatases is composed of lipins 1-3, which are members of the conserved haloacid dehalogenase superfamily. Although genetic alteration of LPIN2 in humans is known to cause Majeed syndrome, little is known about the biochemical regulation of its PAP activity. Here, in an attempt to gain a better general understanding of the biochemical nature of lipin 2, we have performed kinetic and phosphorylation analyses. We provide evidence that lipin 2, like lipin 1, binds PA via the electrostatic hydrogen bond switch mechanism but has a lower rate of catalysis. Like lipin 1, lipin 2 is highly phosphorylated, and we identified 15 phosphosites. However, unlike lipin 1, the phosphorylation of lipin 2 is not induced by insulin signaling nor is it sensitive to inhibition of the mammalian target of rapamycin. Importantly, phosphorylation of lipin 2 does not negatively regulate either membrane binding or PAP activity. This suggests that lipin 2 functions as a constitutively active PA phosphatase in stark contrast to the high degree of phosphorylation-mediated regulation of lipin 1. This knowledge of lipin 2 regulation is important for a deeper understanding of how the lipin family functions with respect to lipid synthesis and, more generally, as an example of how the membrane environment around PA can influence its effector proteins. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Arabidopsis TH2 Encodes the Orphan Enzyme Thiamin Monophosphate Phosphatase[OPEN

PubMed Central

Niehaus, Thomas D.; Hasnain, Ghulam; Gidda, Satinder K.; Nguyen, Thuy N.D.; Anderson, Erin M.; Brown, Greg; Yakunin, Alexander F.; de Crécy-Lagard, Valérie; Gregory, Jesse F.

2016-01-01

To synthesize the cofactor thiamin diphosphate (ThDP), plants must first hydrolyze thiamin monophosphate (ThMP) to thiamin, but dedicated enzymes for this hydrolysis step were unknown and widely doubted to exist. The classical thiamin-requiring th2-1 mutation in Arabidopsis thaliana was shown to reduce ThDP levels by half and to increase ThMP levels 5-fold, implying that the THIAMIN REQUIRING2 (TH2) gene product could be a dedicated ThMP phosphatase. Genomic and transcriptomic data indicated that TH2 corresponds to At5g32470, encoding a HAD (haloacid dehalogenase) family phosphatase fused to a TenA (thiamin salvage) family protein. Like the th2-1 mutant, an insertional mutant of At5g32470 accumulated ThMP, and the thiamin requirement of the th2-1 mutant was complemented by wild-type At5g32470. Complementation tests in Escherichia coli and enzyme assays with recombinant proteins confirmed that At5g32470 and its maize (Zea mays) orthologs GRMZM2G148896 and GRMZM2G078283 are ThMP-selective phosphatases whose activity resides in the HAD domain and that the At5g32470 TenA domain has the expected thiamin salvage activity. In vitro and in vivo experiments showed that alternative translation start sites direct the At5g32470 protein to the cytosol and potentially also to mitochondria. Our findings establish that plants have a dedicated ThMP phosphatase and indicate that modest (50%) ThDP depletion can produce severe deficiency symptoms. PMID:27677881

Engineering a Catabolic Pathway in Plants for the Degradation of 1,2-Dichloroethane1[OA

PubMed Central

Mena-Benitez, Gilda L.; Gandia-Herrero, Fernando; Graham, Stuart; Larson, Tony R.; McQueen-Mason, Simon J.; French, Christopher E.; Rylott, Elizabeth L.; Bruce, Neil C.

2008-01-01

Plants are increasingly being employed to clean up environmental pollutants such as heavy metals; however, a major limitation of phytoremediation is the inability of plants to mineralize most organic pollutants. A key component of organic pollutants is halogenated aliphatic compounds that include 1,2-dichloroethane (1,2-DCA). Although plants lack the enzymatic activity required to metabolize this compound, two bacterial enzymes, haloalkane dehalogenase (DhlA) and haloacid dehalogenase (DhlB) from the bacterium Xanthobacter autotrophicus GJ10, have the ability to dehalogenate a range of halogenated aliphatics, including 1,2-DCA. We have engineered the dhlA and dhlB genes into tobacco (Nicotiana tabacum ‘Xanthi’) plants and used 1,2-DCA as a model substrate to demonstrate the ability of the transgenic tobacco to remediate a range of halogenated, aliphatic hydrocarbons. DhlA converts 1,2-DCA to 2-chloroethanol, which is then metabolized to the phytotoxic 2-chloroacetaldehyde, then chloroacetic acid, by endogenous plant alcohol dehydrogenase and aldehyde dehydrogenase activities, respectively. Chloroacetic acid is dehalogenated by DhlB to produce the glyoxylate cycle intermediate glycolate. Plants expressing only DhlA produced phytotoxic levels of chlorinated intermediates and died, while plants expressing DhlA together with DhlB thrived at levels of 1,2-DCA that were toxic to DhlA-expressing plants. This represents a significant advance in the development of a low-cost phytoremediation approach toward the clean-up of halogenated organic pollutants from contaminated soil and groundwater. PMID:18467461

Effect of Zn2+ on halohydrin dehalogenase expression and accumulation through multi-parameter correlation research with Escherichia coli P84A/MC1061

PubMed Central

Li, Xiao; Luo, Yu-Di; Pan, Dong-Rui; Shi, Xiao-Dan; Tan, Ya-Li; Li, Zhi-Hong

2017-01-01

ABSTRACT Using 5 Zn2+ supplementation strategies in a 50 L batch bioreactor named FUS-50L(A), possible correlations among Zn2+ content and addition timing, physiologic activity (PA), halohydrin dehalogenase (HheC) accumulation of Escherichia coli P84A/MC1061 were systematically investigated. First, Zn2+ was confirmed as the significant factor, and its optimal concentration for HheC expression was 3.87 mg/L through fermentation experiments in shaking flasks. Second, based on experimental results from the different strategies, it was found that PA, nutrient consumption rate (NCR) and specific growth rate (μ) for E. coli P84A/MC1061 were promoted in the log phase (4–8 h) under appropriate Zn2+ concentrations in the lag phase and late log phase. Furthermore cell biomass was also increased to a higher level and the maximum HheC activity (i.e. HheCmax) was increased by 9.80%, and the time to reach HheCmax was reduced from 16 to 12 hours. Furthermore, appropriate supplementation of Zn2+ caused higher μ for E. coli P84A/MC1061, which resulted in more rapid accumulation of increased acetic acid concentrations, leading to higher acetic acid consumption avoiding any negative effects on producing HheC because of carbon source being exhausted prematurely and acetic acid being consumed rapidly. PMID:28282255

Understanding the impact of water distribution system conditions on the biodegradation of haloacetic acids and expression of bacterial dehalogenase genes.

PubMed

Behbahani, Mohsen; Lin, Boren; Phares, Tamara L; Seo, Youngwoo

2018-06-05

The objective of this study is to evaluate the influence of water distribution system conditions (pH, total organic carbon, residual chlorine, and phosphate) on haloacetic acids (HAAs) biodegradation. A series of batch microcosm tests were conducted to determine biodegradation kinetics and collected biomass was used for real time quantitative reverse transcription polymerase chain reaction analyses to monitor how these drinking water distribution system conditions affect the relative expression of bacterial dehalogenase genes. It was observed that tested water distribution system conditions affected HAA biodegradation with different removal efficiencies (0-100%). HAA biodegradation was improved in tested samples with TOC (3 mg/L) and pH 8.5 compared to those of TOC (0 mg/L) and pH 7, respectively. However, slight improvement was observed with the increased PO 4 concentration (3.5 mg/L), and the presence of residual chlorine even at low concentration prohibited biodegradation of HAAs. The observed trend in the relative expression of dehII genes was compatible with the HAA biodegradation trend. Overall relative expression ratio of dehII genes was lower at pH 7, phosphate (0.5 mg/L), and TOC (0 mg/L) in comparison with pH 8.5, phosphate (3.5 mg/L), and TOC (3 mg/L) in the same experimental conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of sulfur oxyanions on reductive dehalogenation activities in Desulfomonile tiedjei.

PubMed Central

Townsend, G T; Suflita, J M

1997-01-01

The inhibition of aryl reductive dehalogenation reactions by sulfur oxyanions has been demonstrated in environmental samples, dehalogenating enrichments, and the sulfate-reducing bacterium Desulfomonile tiedjei; however, this phenomenon is not well understood. We examined the effects of sulfate, sulfite, and thiosulfate on reductive dehalogenation in the model microorganism D. tiedjei and found separate mechanisms of inhibition due to these oxyanions under growth versus nongrowth conditions. Dehalogenation activity was greatly reduced in extracts of cells grown in the presence of both 3-chlorobenzoate, the substrate or inducer for the aryl dehalogenation activity, and either sulfate, sulfite, or thiosulfate, indicating that sulfur oxyanions repress the requisite enzymes. In extracts of fully induced cells, thiosulfate and sulfite, but not sulfate, were potent inhibitors of aryl dehalogenation activity even in membrane fractions lacking the cytoplasmically located sulfur oxyanion reductase. These results suggest that under growth conditions, sulfur oxyanions serve as preferred electron acceptors and negatively influence dehalogenation activity in D. tiedjei by regulating the amount of active aryl dehalogenase in cells. Additionally, in vitro inhibition by sulfur oxyanions is due to the interaction of the reactive species with enzymes involved in dehalogenation and need not involve competition between two respiratory processes for reducing equivalents. Sulfur oxyanions also inhibited tetrachloroethylene dehalogenation by the same mechanisms, further indicating that chloroethylenes are fortuitously dehalogenated by the aryl dehalogenase. The commonly observed inhibition of reductive dehalogenation reactions under sulfate-reducing conditions may be due to similar regulation mechanisms in other dehalogenating microorganisms that contain multiple respiratory activities. PMID:9293011

Structural basis for the substrate selectivity of a HAD phosphatase from Thermococcus onnurineus NA1.

PubMed

Ngo, Tri Duc; Van Le, Binh; Subramani, Vinod Kumar; Thi Nguyen, Chi My; Lee, Hyun Sook; Cho, Yona; Kim, Kyeong Kyu; Hwang, Hye-Yeon

2015-05-22

Proteins in the haloalkaloic acid dehalogenase (HAD) superfamily, which is one of the largest enzyme families, is generally composed of a catalytic core domain and a cap domain. Although proteins in this family show broad substrate specificities, the mechanisms of their substrate recognition are not well understood. In this study, we identified a new substrate binding motif of HAD proteins from structural and functional analyses, and propose that this motif might be crucial for interacting with hydrophobic rings of substrates. The crystal structure of TON_0338, one of the 17 putative HAD proteins identified in a hyperthermophilic archaeon, Thermococcus onnurineus NA1, was determined as an apo-form at 2.0 Å resolution. In addition, we determined the crystal structure TON_0338 in complex with Mg(2+) or N-cyclohexyl-2-aminoethanesulfonic acid (CHES) at 1.7 Å resolution. Examination of the apo-form and CHES-bound structures revealed that CHES is sandwiched between Trp58 and Trp61, suggesting that this Trp sandwich might function as a substrate recognition motif. In the phosphatase assay, TON_0338 was shown to have high activity for flavin mononucleotide (FMN), and the docking analysis suggested that the flavin of FMN may interact with Trp58 and Trp61 in a way similar to that observed in the crystal structure. Moreover, the replacement of these tryptophan residues significantly reduced the phosphatase activity for FMN. Our results suggest that WxxW may function as a substrate binding motif in HAD proteins, and expand the diversity of their substrate recognition mode. Copyright © 2015 Elsevier Inc. All rights reserved.

Biochemical and biophysical characterisation of haloalkane dehalogenases DmrA and DmrB in Mycobacterium strain JS60 and their role in growth on haloalkanes.

PubMed

Fung, Herman K H; Gadd, Morgan S; Drury, Thomas A; Cheung, Samantha; Guss, J Mitchell; Coleman, Nicholas V; Matthews, Jacqueline M

2015-08-01

Haloalkane dehalogenases (HLDs) catalyse the hydrolysis of haloalkanes to alcohols, offering a biological solution for toxic haloalkane industrial wastes. Hundreds of putative HLD genes have been identified in bacterial genomes, but relatively few enzymes have been characterised. We identified two novel HLDs in the genome of Mycobacterium rhodesiae strain JS60, an isolate from an organochlorine-contaminated site: DmrA and DmrB. Both recombinant enzymes were active against C2-C6 haloalkanes, with a preference for brominated linear substrates. However, DmrA had higher activity against a wider range of substrates. The kinetic parameters of DmrA with 4-bromobutyronitrile as a substrate were Km  = 1.9 ± 0.2 mM, kcat  = 3.1 ± 0.2 s(-1) . DmrB showed the highest activity against 1-bromohexane. DmrA is monomeric, whereas DmrB is tetrameric. We determined the crystal structure of selenomethionyl DmrA to 1.7 Å resolution. A spacious active site and alternate conformations of a methionine side-chain in the slot access tunnel may contribute to the broad substrate activity of DmrA. We show that M. rhodesiae JS60 can utilise 1-iodopropane, 1-iodobutane and 1-bromobutane as sole carbon and energy sources. This ability appears to be conferred predominantly through DmrA, which shows significantly higher levels of upregulation in response to haloalkanes than DmrB. © 2015 John Wiley & Sons Ltd.

Grape pomace compost harbors organohalide-respiring Dehalogenimonas species with novel reductive dehalogenase genes

DOE PAGES

Yang, Yi; Higgins, Steven A.; Yan, Jun; ...

2017-08-15

Here, organohalide-respiring bacteria play key roles in the natural chlorine cycle; however, most of the current knowledge is based on cultures from contaminated environments. We demonstrate that grape pomace compost without prior exposure to chlorinated solvents harbors a Dehalogenimonas ( Dhgm) species capable of using chlorinated ethenes, including the human carcinogen and common groundwater pollutant vinyl chloride (VC) as electron acceptors. Grape pomace microcosms and derived solid-free enrichment cultures were able to dechlorinate trichloroethene (TCE) to less chlorinated daughter products including ethene. 16S rRNA gene amplicon and qPCR analyses revealed the predominance of Dhgm sequences, but no Dehalococcoides mccartyi (more » Dhc) biomarker genes were detected. The enumeration of Dhgm 16S rRNA genes demonstrated VC-dependent growth, and 6.55 ± 0.64 x 10 8 cells were produced per µmole of chloride released. Metagenome sequencing enabled the assembly of a Dhgm draft genome, and 52 putative reductive dehalogenase (RDase) genes were identified. Proteomic workflows identified a putative VC RDase with 49% and 56.1% amino acid similarity to the known VC RDases VcrA and BvcA, respectively. A survey of 1,173 groundwater samples collected from 111 chlorinated solvent-contaminated sites revealed that Dhgm 16S rRNA genes were frequently detected and outnumbered Dhc in 65% of the samples. Dhgm may be more relevant contributors to chlorinated solvent reductive dechlorination in contaminated aquifers than is currently recognized, and non-polluted environments are a source of strictly organohalide-respiring bacteria with novel RDase genes.« less

Grape pomace compost harbors organohalide-respiring Dehalogenimonas species with novel reductive dehalogenase genes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yi; Higgins, Steven A.; Yan, Jun

Here, organohalide-respiring bacteria play key roles in the natural chlorine cycle; however, most of the current knowledge is based on cultures from contaminated environments. We demonstrate that grape pomace compost without prior exposure to chlorinated solvents harbors a Dehalogenimonas ( Dhgm) species capable of using chlorinated ethenes, including the human carcinogen and common groundwater pollutant vinyl chloride (VC) as electron acceptors. Grape pomace microcosms and derived solid-free enrichment cultures were able to dechlorinate trichloroethene (TCE) to less chlorinated daughter products including ethene. 16S rRNA gene amplicon and qPCR analyses revealed the predominance of Dhgm sequences, but no Dehalococcoides mccartyi (more » Dhc) biomarker genes were detected. The enumeration of Dhgm 16S rRNA genes demonstrated VC-dependent growth, and 6.55 ± 0.64 x 10 8 cells were produced per µmole of chloride released. Metagenome sequencing enabled the assembly of a Dhgm draft genome, and 52 putative reductive dehalogenase (RDase) genes were identified. Proteomic workflows identified a putative VC RDase with 49% and 56.1% amino acid similarity to the known VC RDases VcrA and BvcA, respectively. A survey of 1,173 groundwater samples collected from 111 chlorinated solvent-contaminated sites revealed that Dhgm 16S rRNA genes were frequently detected and outnumbered Dhc in 65% of the samples. Dhgm may be more relevant contributors to chlorinated solvent reductive dechlorination in contaminated aquifers than is currently recognized, and non-polluted environments are a source of strictly organohalide-respiring bacteria with novel RDase genes.« less

A single mutation in a tunnel to the active site changes the mechanism and kinetics of product release in haloalkane dehalogenase LinB.

PubMed

Biedermannová, Lada; Prokop, Zbyněk; Gora, Artur; Chovancová, Eva; Kovács, Mihály; Damborsky, Jiří; Wade, Rebecca C

2012-08-17

Many enzymes have buried active sites. The properties of the tunnels connecting the active site with bulk solvent affect ligand binding and unbinding and also the catalytic properties. Here, we investigate ligand passage in the haloalkane dehalogenase enzyme LinB and the effect of replacing leucine by a bulky tryptophan at a tunnel-lining position. Transient kinetic experiments show that the mutation significantly slows down the rate of product release. Moreover, the mechanism of bromide ion release is changed from a one-step process in the wild type enzyme to a two-step process in the mutant. The rate constant of bromide ion release corresponds to the overall steady-state turnover rate constant, suggesting that product release became the rate-limiting step of catalysis in the mutant. We explain the experimental findings by investigating the molecular details of the process computationally. Analysis of trajectories from molecular dynamics simulations with a tunnel detection software reveals differences in the tunnels available for ligand egress. Corresponding differences are seen in simulations of product egress using a specialized enhanced sampling technique. The differences in the free energy barriers for egress of a bromide ion obtained using potential of mean force calculations are in good agreement with the differences in rates obtained from the transient kinetic experiments. Interactions of the bromide ion with the introduced tryptophan are shown to affect the free energy barrier for its passage. The study demonstrates how the mechanism of an enzymatic catalytic cycle and reaction kinetics can be engineered by modification of protein tunnels.

[Physiological and biochemical analysis of the transformants of aerobic methylobacteria expressing the dcm A gene of dichloromethane dehydrogenase].

PubMed

Firsova, Iu E; Doronina, N V; Trotsenko, Iu A

2004-01-01

The transformants of Methylobacterium dichloromethanicum DM4 (DM4-2cr-/pME8220 and DM4-2cr-/pME8221) and of Methylobacterium extorquens AM1 (AM1/pME8220 and AM1/pME8221) that express the dcm A gene of dichloromethane dehalogenase undergo lysis when incubated in the presence of dichloromethane and are sensitive to acidic shock. The lysis of the transformants was found to be related neither to the accumulation of Cl- ions, CH2O, and HCOOH, nor to the impairment of glutathione synthesis or to the maintenance of intracellular pH. The (exo-) Klenow fragment-mediated incorporation of [alpha-32P]dATP into the DNA of the transformants DM4-2cr-/pME8220 and AM1/pME8220 was considerably greater when the transformed cells were incubated with CH2Cl2 than when they were incubated with CH3OH, indicating the occurrence of a significant increase in the total length of gaps. At the same time, the strain AM1 (which lacks dichloromethane dehalogenase) and the dichloromethane-degrading strain DM4 incubated with CH2Cl2 showed an insignificant increase in the total length of the gaps. The transformed cells are likely to lyse due to the relatively inefficient repair of DNA lesions that are induced in response to the alkylating action of S-chloromethylglutathione, an intermediate product of CH2Cl2 degradation. The data obtained suggest that the bacterial mineralization of dichloromethane requires an efficient DNA repair system.

Bacterial diversity and reductive dehalogenase redundancy in a 1,2-dichloroethane-degrading bacterial consortium enriched from a contaminated aquifer

PubMed Central

2010-01-01

Background Bacteria possess a reservoir of metabolic functionalities ready to be exploited for multiple purposes. The use of microorganisms to clean up xenobiotics from polluted ecosystems (e.g. soil and water) represents an eco-sustainable and powerful alternative to traditional remediation processes. Recent developments in molecular-biology-based techniques have led to rapid and accurate strategies for monitoring and identification of bacteria and catabolic genes involved in the degradation of xenobiotics, key processes to follow up the activities in situ. Results We report the characterization of the response of an enriched bacterial community of a 1,2-dichloroethane (1,2-DCA) contaminated aquifer to the spiking with 5 mM lactate as electron donor in microcosm studies. After 15 days of incubation, the microbial community structure was analyzed. The bacterial 16S rRNA gene clone library showed that the most represented phylogenetic group within the consortium was affiliated with the phylum Firmicutes. Among them, known degraders of chlorinated compounds were identified. A reductive dehalogenase genes clone library showed that the community held four phylogenetically-distinct catalytic enzymes, all conserving signature residues previously shown to be linked to 1,2-DCA dehalogenation. Conclusions The overall data indicate that the enriched bacterial consortium shares the metabolic functionality between different members of the microbial community and is characterized by a high functional redundancy. These are fundamental features for the maintenance of the community's functionality, especially under stress conditions and suggest the feasibility of a bioremediation treatment with a potential prompt dehalogenation and a process stability over time. PMID:20170484

High frequency of phylogenetically diverse reductive dehalogenase-homologous genes in deep subseafloor sedimentary metagenomes

PubMed Central

Kawai, Mikihiko; Futagami, Taiki; Toyoda, Atsushi; Takaki, Yoshihiro; Nishi, Shinro; Hori, Sayaka; Arai, Wataru; Tsubouchi, Taishi; Morono, Yuki; Uchiyama, Ikuo; Ito, Takehiko; Fujiyama, Asao; Inagaki, Fumio; Takami, Hideto

2014-01-01

Marine subsurface sediments on the Pacific margin harbor diverse microbial communities even at depths of several hundreds meters below the seafloor (mbsf) or more. Previous PCR-based molecular analysis showed the presence of diverse reductive dehalogenase gene (rdhA) homologs in marine subsurface sediment, suggesting that anaerobic respiration of organohalides is one of the possible energy-yielding pathways in the organic-rich sedimentary habitat. However, primer-independent molecular characterization of rdhA has remained to be demonstrated. Here, we studied the diversity and frequency of rdhA homologs by metagenomic analysis of five different depth horizons (0.8, 5.1, 18.6, 48.5, and 107.0 mbsf) at Site C9001 off the Shimokita Peninsula of Japan. From all metagenomic pools, remarkably diverse rdhA-homologous sequences, some of which are affiliated with novel clusters, were observed with high frequency. As a comparison, we also examined frequency of dissimilatory sulfite reductase genes (dsrAB), key functional genes for microbial sulfate reduction. The dsrAB were also widely observed in the metagenomic pools whereas the frequency of dsrAB genes was generally smaller than that of rdhA-homologous genes. The phylogenetic composition of rdhA-homologous genes was similar among the five depth horizons. Our metagenomic data revealed that subseafloor rdhA homologs are more diverse than previously identified from PCR-based molecular studies. Spatial distribution of similar rdhA homologs across wide depositional ages indicates that the heterotrophic metabolic processes mediated by the genes can be ecologically important, functioning in the organic-rich subseafloor sedimentary biosphere. PMID:24624126

High frequency of phylogenetically diverse reductive dehalogenase-homologous genes in deep subseafloor sedimentary metagenomes.

PubMed

Kawai, Mikihiko; Futagami, Taiki; Toyoda, Atsushi; Takaki, Yoshihiro; Nishi, Shinro; Hori, Sayaka; Arai, Wataru; Tsubouchi, Taishi; Morono, Yuki; Uchiyama, Ikuo; Ito, Takehiko; Fujiyama, Asao; Inagaki, Fumio; Takami, Hideto

2014-01-01

Marine subsurface sediments on the Pacific margin harbor diverse microbial communities even at depths of several hundreds meters below the seafloor (mbsf) or more. Previous PCR-based molecular analysis showed the presence of diverse reductive dehalogenase gene (rdhA) homologs in marine subsurface sediment, suggesting that anaerobic respiration of organohalides is one of the possible energy-yielding pathways in the organic-rich sedimentary habitat. However, primer-independent molecular characterization of rdhA has remained to be demonstrated. Here, we studied the diversity and frequency of rdhA homologs by metagenomic analysis of five different depth horizons (0.8, 5.1, 18.6, 48.5, and 107.0 mbsf) at Site C9001 off the Shimokita Peninsula of Japan. From all metagenomic pools, remarkably diverse rdhA-homologous sequences, some of which are affiliated with novel clusters, were observed with high frequency. As a comparison, we also examined frequency of dissimilatory sulfite reductase genes (dsrAB), key functional genes for microbial sulfate reduction. The dsrAB were also widely observed in the metagenomic pools whereas the frequency of dsrAB genes was generally smaller than that of rdhA-homologous genes. The phylogenetic composition of rdhA-homologous genes was similar among the five depth horizons. Our metagenomic data revealed that subseafloor rdhA homologs are more diverse than previously identified from PCR-based molecular studies. Spatial distribution of similar rdhA homologs across wide depositional ages indicates that the heterotrophic metabolic processes mediated by the genes can be ecologically important, functioning in the organic-rich subseafloor sedimentary biosphere.

One-step methodology for the direct covalent capture of GPCRs from complex matrices onto solid surfaces based on the bioorthogonal reaction between haloalkane dehalogenase and chloroalkanes† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc03887a

PubMed Central

Zeng, Kaizhu; Li, Qian; Wang, Jing; Yin, Guowei; Zhang, Yajun; Xiao, Chaoni; Fan, Taiping; Zheng, Xiaohui

2017-01-01

Protein immobilization techniques play an important role in the development of assays for disease diagnosis and drug discovery. However, many of these approaches are not applicable to transmembrane proteins. G protein-coupled receptors (GPCRs) are the largest protein superfamily encoded by the human genome and are targeted by a quarter of all prescription drugs. GPCRs are highly dynamic and sensitive to changes in the ambient environment, and current immobilization methodologies are not suitable for GPCRs. We used haloalkane dehalogenase (Halo) as an immobilization tag fused to the β2-adrenoceptor (β2-AR), angiotensin II type 1 (AT1) and angiotensin II type 2 (AT2) receptors. The engineered Halo-tag covalently binds to a specific substrate chloroalkane through Asp 106 in the catalytic pocket. The Halo-tagged GPCRs were expressed in Escherichia coli at a suitable yield. Accordingly, we loaded cell lysate containing Halo-tagged GPCRs onto a macroporous silica gel coated with chloroalkane. Morphological characterization indicated a homogeneous monolayer of immobilized Halo-tagged GPCRs on the silica gel surface. The immobilized receptors proved to be surrounded by specific bound phospholipids including PG C18:1/C18:1. We observed a radio-ligand binding ability and ligand-induced conformational changes in the immobilized GPCRs, suggesting the preservation of bioactivity. This method is a one-step approach for the specific immobilization of GPCRs from cell lysates and validates that immobilized receptors retain canonical ligand binding capacity. Our immobilization strategy circumvents labor-intensive purification procedures and minimizes loss of activity. The immobilized receptors can be applied to high-throughput drug and interaction partner screening for GPCRs. PMID:29629116

Genomic, proteomic, and biochemical analysis of the organohalide respiratory pathway in Desulfitobacterium dehalogenans.

PubMed

Kruse, Thomas; van de Pas, Bram A; Atteia, Ariane; Krab, Klaas; Hagen, Wilfred R; Goodwin, Lynne; Chain, Patrick; Boeren, Sjef; Maphosa, Farai; Schraa, Gosse; de Vos, Willem M; van der Oost, John; Smidt, Hauke; Stams, Alfons J M

2015-03-01

Desulfitobacterium dehalogenans is able to grow by organohalide respiration using 3-chloro-4-hydroxyphenyl acetate (Cl-OHPA) as an electron acceptor. We used a combination of genome sequencing, biochemical analysis of redox active components, and shotgun proteomics to study elements of the organohalide respiratory electron transport chain. The genome of Desulfitobacterium dehalogenans JW/IU-DC1(T) consists of a single circular chromosome of 4,321,753 bp with a GC content of 44.97%. The genome contains 4,252 genes, including six rRNA operons and six predicted reductive dehalogenases. One of the reductive dehalogenases, CprA, is encoded by a well-characterized cprTKZEBACD gene cluster. Redox active components were identified in concentrated suspensions of cells grown on formate and Cl-OHPA or formate and fumarate, using electron paramagnetic resonance (EPR), visible spectroscopy, and high-performance liquid chromatography (HPLC) analysis of membrane extracts. In cell suspensions, these components were reduced upon addition of formate and oxidized after addition of Cl-OHPA, indicating involvement in organohalide respiration. Genome analysis revealed genes that likely encode the identified components of the electron transport chain from formate to fumarate or Cl-OHPA. Data presented here suggest that the first part of the electron transport chain from formate to fumarate or Cl-OHPA is shared. Electrons are channeled from an outward-facing formate dehydrogenase via menaquinones to a fumarate reductase located at the cytoplasmic face of the membrane. When Cl-OHPA is the terminal electron acceptor, electrons are transferred from menaquinones to outward-facing CprA, via an as-yet-unidentified membrane complex, and potentially an extracellular flavoprotein acting as an electron shuttle between the quinol dehydrogenase membrane complex and CprA. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Genomic, Proteomic, and Biochemical Analysis of the Organohalide Respiratory Pathway in Desulfitobacterium dehalogenans

PubMed Central

van de Pas, Bram A.; Atteia, Ariane; Krab, Klaas; Hagen, Wilfred R.; Goodwin, Lynne; Chain, Patrick; Boeren, Sjef; Maphosa, Farai; Schraa, Gosse; de Vos, Willem M.; van der Oost, John; Smidt, Hauke

2014-01-01

Desulfitobacterium dehalogenans is able to grow by organohalide respiration using 3-chloro-4-hydroxyphenyl acetate (Cl-OHPA) as an electron acceptor. We used a combination of genome sequencing, biochemical analysis of redox active components, and shotgun proteomics to study elements of the organohalide respiratory electron transport chain. The genome of Desulfitobacterium dehalogenans JW/IU-DC1T consists of a single circular chromosome of 4,321,753 bp with a GC content of 44.97%. The genome contains 4,252 genes, including six rRNA operons and six predicted reductive dehalogenases. One of the reductive dehalogenases, CprA, is encoded by a well-characterized cprTKZEBACD gene cluster. Redox active components were identified in concentrated suspensions of cells grown on formate and Cl-OHPA or formate and fumarate, using electron paramagnetic resonance (EPR), visible spectroscopy, and high-performance liquid chromatography (HPLC) analysis of membrane extracts. In cell suspensions, these components were reduced upon addition of formate and oxidized after addition of Cl-OHPA, indicating involvement in organohalide respiration. Genome analysis revealed genes that likely encode the identified components of the electron transport chain from formate to fumarate or Cl-OHPA. Data presented here suggest that the first part of the electron transport chain from formate to fumarate or Cl-OHPA is shared. Electrons are channeled from an outward-facing formate dehydrogenase via menaquinones to a fumarate reductase located at the cytoplasmic face of the membrane. When Cl-OHPA is the terminal electron acceptor, electrons are transferred from menaquinones to outward-facing CprA, via an as-yet-unidentified membrane complex, and potentially an extracellular flavoprotein acting as an electron shuttle between the quinol dehydrogenase membrane complex and CprA. PMID:25512312

Three dehalogenases and physiological restraints in the biodegradation of haloalkanes by Arthrobacter sp. strain HA1.

PubMed Central

Scholtz, R; Messi, F; Leisinger, T; Cook, A M

1988-01-01

Arthrobacter sp. strain HA1 utilizes 18 C2-to-C8 1-haloalkanes for growth and synthesizes an inducible 1-bromoalkane debrominase of unknown physiological function (R. Scholtz, T. Leisinger, F. Suter, and A.M. Cook, J. Bacteriol. 169:5016-5021, 1987) in addition to an inducible 1-chlorohexane halidohydrolase which dehalogenates some 50 substrates, including alpha, omega-dihaloalkanes. alpha, omega-Dihaloalkanes were utilized by cultures of strain HA1 under certain conditions only. C9 and C8 homologs prevented growth. At suitable concentrations, C7-to-C5 homologs could serve as sole sources of carbon and energy for growth. C4 and C3 homologs could be utilized only in the presence of a second substrate (e.g., butanol), and the C2 homolog was not degraded. Kinetics of growth and substrate utilization indicated that cells of strain HA1 growing in butanol-salts medium could be used to test whether compounds induced the 1-chlorohexane halidohydrolase. No gratuitous induction of synthesis of the enzyme was observed. Many enzyme substrates (e.g., bromobenzene) did not induce synthesis of the enzyme, though the enzyme sequence to degrade the product (phenol) was present. Some inducers (e.g., bromomethane) were enzyme substrates but not growth substrates. In an attempt to find a physiological role for the 1-bromoalkane debrominase, we observed that several long-chain haloaliphatic compounds (greater than C9; e.g., 1-bromohexadecane and 1-chlorohexadecane) were utilized for growth and that induced cells could dehalogenate several 1-haloalkanes (at least C4 to C16). The dehalogenation of the long-chain compounds could not be assayed in the cell extract, so we presume that a third haloalkane dehalogenase was present.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3223767

Biochemical Characterization of a Haloalkane Dehalogenase DadB from Alcanivorax dieselolei B-5

PubMed Central

Li, Anzhang; Shao, Zongze

2014-01-01

Recently, we found that Alcanivorax bacteria from various marine environments were capable of degrading halogenated alkanes. Genome sequencing of A. dieselolei B-5 revealed two putative haloalkane dehalogenase (HLD) genes, which were supposed to be involved in degradation of halogenated compounds. In this report, we confirm for the first time that the Alcanivorax bacterium encodes a truly functional HLD named DadB. An activity assay with 46 halogenated substrates indicated that DadB possesses broad substrate range and has the highest overall activity among the identified HLDs. DadB prefers brominated substrates; chlorinated alkenes; and the C2-C3 substrates, including the persistent pollutants of 1,2-dichloroethane, 1,2-dichloropropane and 1,2,3-trichloropropane. As DadB displays no detectable activity toward long-chain haloalkanes such as 1-chlorohexadecane and 1-chlorooctadecane, the degradation of them in A. dieselolei B-5 might be attributed to other enzymes. Kinetic constants were determined with 6 substrates. DadB has highest affinity and largest k cat/K m value toward 1,3-dibromopropane (K m = 0.82 mM, k cat/K m = 16.43 mM−1·s−1). DadB aggregates fast in the buffers with pH≤7.0, while keeps stable in monomer form when pH≥7.5. According to homology modeling, DadB has an open active cavity with a large access tunnel, which is supposed important for larger molecules as opposed to C2-C3 substrates. Combined with the results for other HLDs, we deduce that residue I247 plays an important role in substrate selection. These results suggest that DadB and its host, A. dieselolei B-5, are of potential use for biocatalysis and bioremediation applications. PMID:24586552

The 38K-Mediated Specific Dephosphorylation of the Viral Core Protein P6.9 Plays an Important Role in the Nucleocapsid Assembly of Autographa californica Multiple Nucleopolyhedrovirus.

PubMed

Lai, Qingying; Wu, Wenbi; Li, Ao; Wang, Wei; Yuan, Meijin; Yang, Kai

2018-05-01

Encapsidation of the viral genomes, leading to the assembly of the nucleocapsids to form infectious progeny virions, is a key step in many virus life cycles. Baculovirus nucleocapsid assembly is a complex process that involves many proteins. Our previous studies showed that the deletion of the core gene 38K ( ac98 ) interrupted the nucleocapsid assembly by producing capsid sheaths devoid of viral genomes by an unknown mechanism. All homologs of 38K contain conserved motifs of the haloacid dehalogenase superfamily, which are involved in phosphoryl transfer. The requirements of these motifs for nucleocapsid assembly, confirmed in the present study, suggest that 38K may be a functioning haloacid dehalogenase. P6.9 is also encoded by a core gene ( ac100 ) and is required for viral genome encapsidation. It has been reported that multiple phosphorylated species of P6.9 are present in virus-infected cells, while only an unphosphorylated species is detected in the budded virus. Therefore, whether 38K mediates the dephosphorylation of P6.9 was investigated. An additional phosphorylated species of P6.9 in 38K -deleted or -mutated virus-transfected cells was detected, and the dephosphorylated sites mediated by 38K were determined by mass spectrometry. To assess the effects of dephosphorylation of P6.9 mediated by 38K on virus replication, these sites were mutated to glutamic acids (phosphorylation-mimic mutant) or to alanines (phosphorylation-deficient mutant). Studies showed that the nucleocapsid assembly was interrupted in phosphorylation-mimic mutant virus-transfected cells. Taken together, our findings demonstrate that 38K mediates the dephosphorylation of specific sites at the C terminus of P6.9, which is essential for viral genome encapsidation. IMPORTANCE Genome packaging is a fundamental process in the virus life cycle, and viruses have different strategies to perform this step. For several double-stranded DNA (dsDNA) viruses, the procapsid is formed before genome encapsidation, which may require basic proteins that help to neutralize the nucleic acid charge repulsion to facilitate the compaction of the genome within the confined capsid space. Baculovirus encodes a small basic protein, P6.9, which is required for a variety of processes in the virus infection cycle. The phosphorylation of P6.9 is thought to result in nucleocapsid uncoating, while the dephosphorylation of P6.9 is involved in viral DNA encapsidation during nucleocapsid assembly. Here, we demonstrate that a haloacid dehalogenase homolog encoded by baculovirus core gene 38K is involved in nucleocapsid assembly by mediating the dephosphorylation of 5 specific sites at the C terminus of P6.9. This finding contributes to the understanding of the mechanisms of virus nucleocapsid assembly. Copyright © 2018 Lai et al.

The 38K-Mediated Specific Dephosphorylation of the Viral Core Protein P6.9 Plays an Important Role in the Nucleocapsid Assembly of Autographa californica Multiple Nucleopolyhedrovirus

PubMed Central

Lai, Qingying; Li, Ao; Wang, Wei; Yuan, Meijin

2018-01-01

ABSTRACT Encapsidation of the viral genomes, leading to the assembly of the nucleocapsids to form infectious progeny virions, is a key step in many virus life cycles. Baculovirus nucleocapsid assembly is a complex process that involves many proteins. Our previous studies showed that the deletion of the core gene 38K (ac98) interrupted the nucleocapsid assembly by producing capsid sheaths devoid of viral genomes by an unknown mechanism. All homologs of 38K contain conserved motifs of the haloacid dehalogenase superfamily, which are involved in phosphoryl transfer. The requirements of these motifs for nucleocapsid assembly, confirmed in the present study, suggest that 38K may be a functioning haloacid dehalogenase. P6.9 is also encoded by a core gene (ac100) and is required for viral genome encapsidation. It has been reported that multiple phosphorylated species of P6.9 are present in virus-infected cells, while only an unphosphorylated species is detected in the budded virus. Therefore, whether 38K mediates the dephosphorylation of P6.9 was investigated. An additional phosphorylated species of P6.9 in 38K-deleted or -mutated virus-transfected cells was detected, and the dephosphorylated sites mediated by 38K were determined by mass spectrometry. To assess the effects of dephosphorylation of P6.9 mediated by 38K on virus replication, these sites were mutated to glutamic acids (phosphorylation-mimic mutant) or to alanines (phosphorylation-deficient mutant). Studies showed that the nucleocapsid assembly was interrupted in phosphorylation-mimic mutant virus-transfected cells. Taken together, our findings demonstrate that 38K mediates the dephosphorylation of specific sites at the C terminus of P6.9, which is essential for viral genome encapsidation. IMPORTANCE Genome packaging is a fundamental process in the virus life cycle, and viruses have different strategies to perform this step. For several double-stranded DNA (dsDNA) viruses, the procapsid is formed before genome encapsidation, which may require basic proteins that help to neutralize the nucleic acid charge repulsion to facilitate the compaction of the genome within the confined capsid space. Baculovirus encodes a small basic protein, P6.9, which is required for a variety of processes in the virus infection cycle. The phosphorylation of P6.9 is thought to result in nucleocapsid uncoating, while the dephosphorylation of P6.9 is involved in viral DNA encapsidation during nucleocapsid assembly. Here, we demonstrate that a haloacid dehalogenase homolog encoded by baculovirus core gene 38K is involved in nucleocapsid assembly by mediating the dephosphorylation of 5 specific sites at the C terminus of P6.9. This finding contributes to the understanding of the mechanisms of virus nucleocapsid assembly. PMID:29444944

A puzzling homology: a brittle star using a putative cnidarian-type luciferase for bioluminescence.

PubMed

Delroisse, Jérôme; Ullrich-Lüter, Esther; Blaue, Stefanie; Ortega-Martinez, Olga; Eeckhaut, Igor; Flammang, Patrick; Mallefet, Jérôme

2017-04-01

Bioluminescence relies on the oxidation of a luciferin substrate catalysed by a luciferase enzyme. Luciferins and luciferases are generic terms used to describe a large variety of substrates and enzymes. Whereas luciferins can be shared by phylogenetically distant organisms which feed on organisms producing them, luciferases have been thought to be lineage-specific enzymes. Numerous light emission systems would then have co-emerged independently along the tree of life resulting in a plethora of non-homologous luciferases. Here, we identify for the first time a candidate luciferase of a luminous echinoderm, the ophiuroid Amphiura filiformis Phylogenomic analyses identified the brittle star predicted luciferase as homologous to the luciferase of the sea pansy Renilla (Cnidaria), contradicting with the traditional viewpoint according to which luciferases would generally be of convergent origins. The similarity between the Renilla and Amphiura luciferases allowed us to detect the latter using anti- Renilla luciferase antibodies. Luciferase expression was specifically localized in the spines which were demonstrated to be the bioluminescent organs in vivo However, enzymes homologous to the Renilla luciferase but unable to trigger light emission were also identified in non-luminous echinoderms and metazoans. Our findings strongly indicate that those enzymes, belonging to the haloalkane dehalogenase family, might then have been convergently co-opted into luciferases in cnidarians and echinoderms. In these two benthic suspension-feeding species, similar ecological pressures would constitute strong selective forces for the functional shift of these enzymes and the emergence of bioluminescence. © 2017 The Authors.

A puzzling homology: a brittle star using a putative cnidarian-type luciferase for bioluminescence

PubMed Central

Ullrich-Lüter, Esther; Blaue, Stefanie; Ortega-Martinez, Olga; Eeckhaut, Igor; Flammang, Patrick; Mallefet, Jérôme

2017-01-01

Bioluminescence relies on the oxidation of a luciferin substrate catalysed by a luciferase enzyme. Luciferins and luciferases are generic terms used to describe a large variety of substrates and enzymes. Whereas luciferins can be shared by phylogenetically distant organisms which feed on organisms producing them, luciferases have been thought to be lineage-specific enzymes. Numerous light emission systems would then have co-emerged independently along the tree of life resulting in a plethora of non-homologous luciferases. Here, we identify for the first time a candidate luciferase of a luminous echinoderm, the ophiuroid Amphiura filiformis. Phylogenomic analyses identified the brittle star predicted luciferase as homologous to the luciferase of the sea pansy Renilla (Cnidaria), contradicting with the traditional viewpoint according to which luciferases would generally be of convergent origins. The similarity between the Renilla and Amphiura luciferases allowed us to detect the latter using anti-Renilla luciferase antibodies. Luciferase expression was specifically localized in the spines which were demonstrated to be the bioluminescent organs in vivo. However, enzymes homologous to the Renilla luciferase but unable to trigger light emission were also identified in non-luminous echinoderms and metazoans. Our findings strongly indicate that those enzymes, belonging to the haloalkane dehalogenase family, might then have been convergently co-opted into luciferases in cnidarians and echinoderms. In these two benthic suspension-feeding species, similar ecological pressures would constitute strong selective forces for the functional shift of these enzymes and the emergence of bioluminescence. PMID:28381628

Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

NASA Technical Reports Server (NTRS)

Smith, G. B.

1996-01-01

The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

Phenol Is the Initial Product Formed during Growth and Degradation of Bromobenzene by Tropical Marine Yeast, Yarrowia lipolytica NCIM 3589 via an Early Dehalogenation Step.

PubMed

Vatsal, Aakanksha A; Zinjarde, Smita S; RaviKumar, Ameeta

2017-01-01

Bromobenzene (BrB), a hydrophobic, recalcitrant organic compound, is listed by the environmental protection agencies as an environmental and marine pollutant having hepatotoxic, mutagenic, teratogenic, and carcinogenic effects. The tropical marine yeast Yarrowia lipolytica 3589 was seen to grow aerobically on BrB and displayed a maximum growth rate (μ max ) of 0.04 h -1 . Furthermore, we also observed an increase in cell size and sedimentation velocity for the cells grown on BrB as compared to the glucose grown cells. The cells attached to the hydrophobic bromobenzene droplets through its hydrophobic and acid-base interactions. The BrB (0.5%, 47.6 mM) was utilized by the cells with the release of a corresponding amount of bromide (12.87 mM) and yielded a cell mass of 1.86 g/L after showing 34% degradation in 96 h. Maximum dehalogenase activity of 16.16 U/mL was seen in the cell free supernatant after 24 h of growth. Identification of metabolites formed as a result of BrB degradation, namely, phenol, catechol, cis, cis muconic acid, and carbon dioxide were determined by LC-MS and GC-MS. The initial attack on bromobenzene by Y. lipolytica cells lead to the transient accumulation of phenol as an early intermediate which is being reported for the first time. Degradation of phenol led to catechol which was degraded by the ortho- cleavage pathway forming cis, cis muconic acid and then to Krebs cycle intermediates eventually leading to CO 2 production. The study shows that dehalogenation via an extracellular dehalogenase occurs prior to ring cleavage with phenol as the preliminary degradative compound being produced. The yeast was also able to grow on the degradative products, i.e., phenol and catechol, to varying degrees which would be of potential relevance in the degradation and remediation of xenobiotic environmental bromoaromatic pollutants such as bromobenzene.

Phenol Is the Initial Product Formed during Growth and Degradation of Bromobenzene by Tropical Marine Yeast, Yarrowia lipolytica NCIM 3589 via an Early Dehalogenation Step

PubMed Central

Vatsal, Aakanksha A.; Zinjarde, Smita S.; RaviKumar, Ameeta

2017-01-01

Bromobenzene (BrB), a hydrophobic, recalcitrant organic compound, is listed by the environmental protection agencies as an environmental and marine pollutant having hepatotoxic, mutagenic, teratogenic, and carcinogenic effects. The tropical marine yeast Yarrowia lipolytica 3589 was seen to grow aerobically on BrB and displayed a maximum growth rate (μmax) of 0.04 h-1. Furthermore, we also observed an increase in cell size and sedimentation velocity for the cells grown on BrB as compared to the glucose grown cells. The cells attached to the hydrophobic bromobenzene droplets through its hydrophobic and acid–base interactions. The BrB (0.5%, 47.6 mM) was utilized by the cells with the release of a corresponding amount of bromide (12.87 mM) and yielded a cell mass of 1.86 g/L after showing 34% degradation in 96 h. Maximum dehalogenase activity of 16.16 U/mL was seen in the cell free supernatant after 24 h of growth. Identification of metabolites formed as a result of BrB degradation, namely, phenol, catechol, cis, cis muconic acid, and carbon dioxide were determined by LC–MS and GC–MS. The initial attack on bromobenzene by Y. lipolytica cells lead to the transient accumulation of phenol as an early intermediate which is being reported for the first time. Degradation of phenol led to catechol which was degraded by the ortho- cleavage pathway forming cis, cis muconic acid and then to Krebs cycle intermediates eventually leading to CO2 production. The study shows that dehalogenation via an extracellular dehalogenase occurs prior to ring cleavage with phenol as the preliminary degradative compound being produced. The yeast was also able to grow on the degradative products, i.e., phenol and catechol, to varying degrees which would be of potential relevance in the degradation and remediation of xenobiotic environmental bromoaromatic pollutants such as bromobenzene. PMID:28690604

Site-Specific, Covalent Immobilization of Dehalogenase ST2570 Catalyzed by Formylglycine-Generating Enzymes and Its Application in Batch and Semi-Continuous Flow Reactors.

PubMed

Jian, Hui; Wang, Yingwu; Bai, Yan; Li, Rong; Gao, Renjun

2016-07-11

Formylglycine-generating enzymes can selectively recognize and oxidize cysteine residues within the sulfatase sub motif at the terminus of proteins to form aldehyde-bearing formylglycine (FGly) residues, and are normally used in protein labeling. In this study, an aldehyde tag was introduced to proteins using formylglycine-generating enzymes encoded by a reconstructed set of the pET28a plasmid system for enzyme immobilization. The haloacid dehalogenase ST2570 from Sulfolobus tokodaii was used as a model enzyme. The C-terminal aldehyde-tagged ST2570 (ST2570CQ) exhibited significant enzymological properties, such as new free aldehyde groups, a high level of protein expression and improved enzyme activity. SBA-15 has widely been used as an immobilization support for its large surface and excellent thermal and chemical stability. It was functionalized with amino groups by aminopropyltriethoxysilane. The C-terminal aldehyde-tagged ST2570 was immobilized to SBA-15 by covalent binding. The site-specific immobilization of ST2570 avoided the chemical denaturation that occurs in general covalent immobilization and resulted in better fastening compared to physical adsorption. The site-specific immobilized ST2570 showed 3-fold higher thermal stability, 1.2-fold higher catalytic ability and improved operational stability than free ST2570. The site-specific immobilized ST2570 retained 60% of its original activity after seven cycles of batch operation, and it was superior to the ST2570 immobilized to SBA-15 by physical adsorption, which loses 40% of its original activity when used for the second time. It is remarkable that the site-specific immobilized ST2570 still retained 100% of its original activity after 10 cycles of reuse in the semi-continuous flow reactor. Overall, these results provide support for the industrial-scale production and application of site-specific, covalently immobilized ST2570.

A Pre-Steady State Kinetic Analysis of the αY60W mutant of trans-3-Chloroacrylic Acid Dehalogenase: Implications for the Mechanism of the Wild-type Enzyme†

PubMed Central

Huddleston, Jamison P.; Schroeder, Gottfried K.; Johnson, Kenneth A.; Whitman, Christian P.

2012-01-01

The bacterial degradation of the nematicide 1,3-dichloropropene, an isomeric mixture, requires the action of trans- and cis-3-chloracrylic acid dehalogenase (CaaD and cis-CaaD, respectively). Both enzymes are tautomerase superfamily members and share a core catalytic mechanism for the hydrolytic dehalogenation of the respective isomer of 3-haloacrylate. The observation that cis-CaaD requires two additional residues raises the question of how CaaD carries out a comparable reaction with fewer catalytic residues. As part of an effort to determine the basis for the apparently simpler CaaD-catalyzed reaction, the kinetic mechanism was determined by stopped-flow and chemical quench techniques using a fluorescent mutant form of the enzyme, αY60W-CaaD, and trans-3-bromoacrylate as the substrate. The data from these experiments as well as bromide inhibition studies are best accommodated by a six-step model that provides individual rate constants for substrate binding, chemistry, and a proposed conformational change occurring after chemistry followed by release of malonate semialdehyde and bromide. The conformational change and product release rates are comparable and together they limit the rate of turnover. The kinetic analysis and modeling studies validate the αY60W-CaaD mutant as an accurate reporter of active site events during the course of the enzyme-catalyzed reaction. The kinetic mechanism for the αY60W-CaaD-catalyzed reaction is comparable to that obtained for the cis-CaaD-catalyzed reaction. The kinetic model and the validated αY60W-CaaD mutant set the stage for an analysis of active site mutants to explore the contributions of individual catalytic residues and the basis for the simplicity of the reaction. PMID:23110338

Degradation of 2-chloroallylalcohol by a Pseudomonas sp.

PubMed Central

van der Waarde, J J; Kok, R; Janssen, D B

1993-01-01

Three Pseudomonas strains capable of utilizing 2-chloroallylalcohol (2-chloropropenol) as the sole carbon source for growth were isolated from soil. The fastest growth was observed with strain JD2, with a generation time of 3.6 h. Degradation of 2-chloroallylalcohol was accompanied by complete dehalogenation. Chloroallylalcohols that did not support growth were dechlorinated by resting cells; the dechlorination level was highest if an alpha-chlorine substituent was present. Crude extracts of strain JD2 contained inducible alcohol dehydrogenase activity that oxidized mono- and dichloroallylalcohols but not trichloroallylalcohol. The enzyme used phenazine methosulfate as an artificial electron acceptor. Further oxidation yielded 2-chloroacrylic acid. The organism also produced hydrolytic dehalogenases converting 2-chloroacetic acid and 2-chloropropionic acid. PMID:8434917

[Adaptation of aerobic methylobacteria to dichloromethane degradation].

PubMed

Torgonskaia, M L; Firsova, Iu E; Doronina, N V; Trotsenko, Iu A

2007-01-01

A shortening of the lag phase in dichloromethane (DCM) consumption was observed in the methylobacteria Methylopila helvetica DM6 and Albibacter methylovorans DM10 after prior growth on methanol with the presence of 1.5% NaCI. Neither heat nor acid stress accelerated methylobacterium adaptation to DCM consumption. Sodium azide (1 mM) and potassium cyanide (1 mM) inhibited consumption of DCM by these degraders but not by transconjugants Methylobacterium extorquens AM1, expressing DCM dehalogenase but unable to grow on DCM. This indicates that the degrader strains possess energy-dependent systems of transport of DCM or chloride anions produced during DCM dehalogenation. Inducible proteins were found in the membrane fraction of A. methylovorans DM10 cells adapted to DCM and elevated NaCl concentration.

Large Plasmids from Soil Bacteria Enriched on Halogenated Alkanoic Acids

PubMed Central

Hardman, David J.; Gowland, Peter C.; Slater, J. Howard

1986-01-01

Four Pseudomonas species and two Alcaligenes species were isolated from soil with a capacity to grow on halogenated alkanoic acids. They were shown to contain one of five large plasmids. The plasmids had molecular weights ranging from 98,800 to 190,000. They were associated with the ability to utilize the halogenated substrates 2-monochloropropionic acid and 2-monochloroacetic acid and with resistance towards one or more of the heavy metals mercury, selenium, and tellurium. The largest plasmid, pUU204, was shown to be unstable in continuous-flow culture when the organism was supplied with succinate as the sole carbon source. The dehalogenase gene associated with pUU204 appeared to be readily transferred to an incP group plasmid, R68-45. PMID:16346975

Anaerobic microbial dehalogenation of organohalides-state of the art and remediation strategies.

PubMed

Nijenhuis, Ivonne; Kuntze, Kevin

2016-04-01

Contamination and remediation of groundwater with halogenated organics and understanding of involved microbial reactions still poses a challenge. Over the last years, research in anaerobic microbial dehalogenation has advanced in many aspects providing information about the reaction, physiology of microorganisms as well as approaches to investigate the activity of microorganisms in situ. Recently published crystal structures of reductive dehalogenases (Rdh), heterologous expression systems and advanced analytical, proteomic and stable isotope approaches allow addressing the overall reaction and specific enzymes as well as co-factors involved during anaerobic microbial dehalogenation. In addition to Dehalococcoides spp., Dehalobacter and Dehalogenimonas strains have been recognized as important and versatile organohalide respirers. Together, these provide perspectives for integrated concepts allowing to improve and monitor in situ biodegradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Metagenomics as a Tool for Enzyme Discovery: Hydrolytic Enzymes from Marine-Related Metagenomes.

PubMed

Popovic, Ana; Tchigvintsev, Anatoly; Tran, Hai; Chernikova, Tatyana N; Golyshina, Olga V; Yakimov, Michail M; Golyshin, Peter N; Yakunin, Alexander F

2015-01-01

This chapter discusses metagenomics and its application for enzyme discovery, with a focus on hydrolytic enzymes from marine metagenomic libraries. With less than one percent of culturable microorganisms in the environment, metagenomics, or the collective study of community genetics, has opened up a rich pool of uncharacterized metabolic pathways, enzymes, and adaptations. This great untapped pool of genes provides the particularly exciting potential to mine for new biochemical activities or novel enzymes with activities tailored to peculiar sets of environmental conditions. Metagenomes also represent a huge reservoir of novel enzymes for applications in biocatalysis, biofuels, and bioremediation. Here we present the results of enzyme discovery for four enzyme activities, of particular industrial or environmental interest, including esterase/lipase, glycosyl hydrolase, protease and dehalogenase.

Phytoremediation of small organic contaminants using transgenic plants

PubMed Central

James, C Andrew; Strand, Stuart E

2010-01-01

The efficacy of transgenic plants in the phytoremediation of small organic contaminants has been investigated. Two principal strategies have been pursued (1) the manipulation of phase I metabolic activity to enhance in planta degradation rates, or to impart novel metabolic activity, and (2) the enhanced secretion of reactive enzymes from roots leading to accelerated ex planta degradation of organic contaminants. A pair of dehalogenase genes from Xanthobacter autotrophicus was expressed in tobacco resulting in the dehalogenation of 1,2-dichloroethane, which was otherwise recalcitrant. A laccase gene from cotton was overexpressed in Arabidopsis thaliana resulting in increased secretory laccase activity and the enhanced resistance to trichlorophenol in soils. Although the results to date are promising, much of the work has been limited to laboratory settings; field demonstrations are needed. PMID:19342219

Reductive Dechlorination of Carbon Tetrachloride by Tetrachloroethene and Trichloroethene Respiring Anaerobic Mixed Cultures

NASA Astrophysics Data System (ADS)

Vickstrom, K. E.; Azizian, M.; Semprini, L.

2015-12-01

Carbon tetrachloride (CT) is a toxic and recalcitrant groundwater contaminant with the potential to form a broad range of transformation products. Of the possible biochemical pathways through which CT can be degraded, reductive dehalogenation to less chlorinated compounds and mineralization to carbon dioxide (CO2) appear to be the most frequently utilized pathways by anaerobic organisms. Results will be presented from batch experiments of CT degradation by the Evanite (EV), Victoria Strain (VS) and Point Mugu (PM) anaerobic dechlorinating cultures. The cultures are grown in chemostats and are capable of transforming tetrachloroethene (PCE) or trichloroethene (TCE) to ethene by halorespiration via reductive dehalogenase enzymes. For the batch CT transformation tests, the cells along with supernatant were harvested from chemostats fed PCE or TCE, but never CT. The batch reactors were initially fed 0.0085 mM CT and an excess of formate (EV and VS) or lactate (PM) as electron donor. Transformation of CT was 100% with about 20% converted to chloroform (CF) and undetected products. Multiple additions of CT showed a slowing of pseudo first-order CT transformation rates across all cultures. Batch reactors were then established and fed 0.085 mM CT with an excess of electron donor in order to better quantify the reductive pathway. CT was transformed to CF and dichloromethane (DCM), with trace amounts of chloromethane (CM) detected. Between 60-90% of the mass added to the system was accounted for, showing that the majority of the carbon tetrachloride present is being reductively dehalogenated. Results from batch reactors that were poisoned using sodium azide, and from reactors not provided electron donor will be presented to distinguish between biotic and abiotic reactions. Furthermore, results from reactors prepared with acetylene (a potent, reversible inhibitor of reductive dehalogenases (1)) will be presented as a means of identifying the enzymes involved in the transformation of CT. The results clearly demonstrate that reductive dechlorination of CT can be promoted by anaerobic cultures not previously acclimated to CT. 1. G. Pon, M. R. Hyman, L. Semprini, Environ. Sci. Technol. 37, 3181-3188 (2003).

Comparative Single-Cell Genomics of Chloroflexi from the Okinawa Trough Deep-Subsurface Biosphere.

PubMed

Fullerton, Heather; Moyer, Craig L

2016-05-15

Chloroflexi small-subunit (SSU) rRNA gene sequences are frequently recovered from subseafloor environments, but the metabolic potential of the phylum is poorly understood. The phylum Chloroflexi is represented by isolates with diverse metabolic strategies, including anoxic phototrophy, fermentation, and reductive dehalogenation; therefore, function cannot be attributed to these organisms based solely on phylogeny. Single-cell genomics can provide metabolic insights into uncultured organisms, like the deep-subsurface Chloroflexi Nine SSU rRNA gene sequences were identified from single-cell sorts of whole-round core material collected from the Okinawa Trough at Iheya North hydrothermal field as part of Integrated Ocean Drilling Program (IODP) expedition 331 (Deep Hot Biosphere). Previous studies of subsurface Chloroflexi single amplified genomes (SAGs) suggested heterotrophic or lithotrophic metabolisms and provided no evidence for growth by reductive dehalogenation. Our nine Chloroflexi SAGs (seven of which are from the order Anaerolineales) indicate that, in addition to genes for the Wood-Ljungdahl pathway, exogenous carbon sources can be actively transported into cells. At least one subunit for pyruvate ferredoxin oxidoreductase was found in four of the Chloroflexi SAGs. This protein can provide a link between the Wood-Ljungdahl pathway and other carbon anabolic pathways. Finally, one of the seven Anaerolineales SAGs contains a distinct reductive dehalogenase homologous (rdhA) gene. Through the use of single amplified genomes (SAGs), we have extended the metabolic potential of an understudied group of subsurface microbes, the Chloroflexi These microbes are frequently detected in the subsurface biosphere, though their metabolic capabilities have remained elusive. In contrast to previously examined Chloroflexi SAGs, our genomes (several are from the order Anaerolineales) were recovered from a hydrothermally driven system and therefore provide a unique window into the metabolic potential of this type of habitat. In addition, a reductive dehalogenase gene (rdhA) has been directly linked to marine subsurface Chloroflexi, suggesting that reductive dehalogenation is not limited to the class Dehalococcoidia This discovery expands the nutrient-cycling and metabolic potential present within the deep subsurface and provides functional gene information relating to this enigmatic group. Copyright © 2016 Fullerton and Moyer.

Improved catalytic properties of halohydrin dehalogenase by modification of the halide-binding site.

PubMed

Tang, Lixia; Torres Pazmiño, Daniel E; Fraaije, Marco W; de Jong, René M; Dijkstra, Bauke W; Janssen, Dick B

2005-05-03

Halohydrin dehalogenase (HheC) from Agrobacterium radiobacter AD1 catalyzes the dehalogenation of vicinal haloalcohols by an intramolecular substitution reaction, resulting in the formation of the corresponding epoxide, a halide ion, and a proton. Halide release is rate-limiting during the catalytic cycle of the conversion of (R)-p-nitro-2-bromo-1-phenylethanol by the enzyme. The recent elucidation of the X-ray structure of HheC showed that hydrogen bonds between the OH group of Tyr187 and between the Odelta1 atom of Asn176 and Nepsilon1 atom of Trp249 could play a role in stabilizing the conformation of the halide-binding site. The possibility that these hydrogen bonds are important for halide binding and release was studied using site-directed mutagenesis. Steady-state kinetic studies revealed that mutant Y187F, which has lost both hydrogen bonds, has a higher catalytic activity (k(cat)) with two of the three tested substrates compared to the wild-type enzyme. Mutant W249F also shows an enhanced k(cat) value with these two substrates, as well as a remarkable increase in enantiopreference for (R)-p-nitro-2-bromo-1-phenylethanol. In case of a mutation at position 176 (N176A and N176D), a 1000-fold lower catalytic efficiency (k(cat)/K(m)) was obtained, which is mainly due to an increase of the K(m) value of the enzyme. Pre-steady-state kinetic studies showed that a burst of product formation precedes the steady state, indicating that halide release is still rate-limiting for mutants Y187F and W249F. Stopped-flow fluorescence experiments revealed that the rate of halide release is 5.6-fold higher for the Y187F mutant than for the wild-type enzyme and even higher for the W249F enzyme. Taken together, these results show that the disruption of two hydrogen bonds around the halide-binding site increases the rate of halide release and can enhance the overall catalytic activity of HheC.

Single-Cell Genome and Group-Specific dsrAB Sequencing Implicate Marine Members of the Class Dehalococcoidia (Phylum Chloroflexi) in Sulfur Cycling

PubMed Central

Cooper, Myriel; Schreiber, Lars; Lloyd, Karen G.; Baker, Brett J.; Petersen, Dorthe G.; Jørgensen, Bo Barker; Stepanauskas, Ramunas; Reinhardt, Richard; Schramm, Andreas; Loy, Alexander; Adrian, Lorenz

2016-01-01

ABSTRACT The marine subsurface sediment biosphere is widely inhabited by bacteria affiliated with the class Dehalococcoidia (DEH), phylum Chloroflexi, and yet little is known regarding their metabolisms. In this report, genomic content from a single DEH cell (DEH-C11) with a 16S rRNA gene that was affiliated with a diverse cluster of 16S rRNA gene sequences prevalent in marine sediments was obtained from sediments of Aarhus Bay, Denmark. The distinctive gene content of this cell suggests metabolic characteristics that differ from those of known DEH and Chloroflexi. The presence of genes encoding dissimilatory sulfite reductase (Dsr) suggests that DEH could respire oxidized sulfur compounds, although Chloroflexi have never been implicated in this mode of sulfur cycling. Using long-range PCR assays targeting DEH dsr loci, dsrAB genes were amplified and sequenced from various marine sediments. Many of the amplified dsrAB sequences were affiliated with the DEH Dsr clade, which we propose equates to a family-level clade. This provides supporting evidence for the potential for sulfite reduction by diverse DEH species. DEH-C11 also harbored genes encoding reductases for arsenate, dimethyl sulfoxide, and halogenated organics. The reductive dehalogenase homolog (RdhA) forms a monophyletic clade along with RdhA sequences from various DEH-derived contigs retrieved from available metagenomes. Multiple facts indicate that this RdhA may not be a terminal reductase. The presence of other genes indicated that nutrients and energy may be derived from the oxidation of substituted homocyclic and heterocyclic aromatic compounds. Together, these results suggest that marine DEH play a previously unrecognized role in sulfur cycling and reveal the potential for expanded catabolic and respiratory functions among subsurface DEH. PMID:27143384

A novel helper phage for HaloTag-mediated co-display of enzyme and substrate on phage.

PubMed

Delespaul, Wouter; Peeters, Yves; Herdewijn, Piet; Robben, Johan

2015-05-01

Phage display is an established technique for the molecular evolution of peptides and proteins. For the selection of enzymes based on catalytic activity however, simultaneous coupling of an enzyme and its substrate to the phage surface is required. To facilitate this process of co-display, we developed a new helper phage displaying HaloTag, a modified haloalkane dehalogenase that binds specifically and covalently to functionalized haloalkane ligands. The display of functional HaloTag was demonstrated by capture on streptavidin-coated magnetic beads, after coupling a biotinylated haloalkane ligand, or after on-phage extension of a DNA oligonucleotide primer with a biotinylated nucleotide by phi29 DNA polymerase. We also achieved co-display of HaloTag and phi29 DNA polymerase, thereby opening perspectives for the molecular evolution of this enzyme (and others) towards new substrate specificities. Copyright © 2015 Elsevier Inc. All rights reserved.

An enzymatic method for determination of azide and cyanide in aqueous phase.

PubMed

Wan, Nan-Wei; Liu, Zhi-Qiang; Xue, Feng; Zheng, Yu-Guo

2015-11-20

A halohydrin dehalogenase (HHDH-PL) from Parvibaculum lavamentivorans DS-1 was characterized and applied to determine azide and cyanide in the water. In this methodology, HHDH-PL catalysed azide and cyanide to react with butylene oxide and form corresponding β-substituted alcohols 1-azidobutan-2-ol (ABO) and 3-hydroxypentanenitrile (HPN) that could be quantitatively detected by gas chromatograph. The detection calibration curves for azide (R(2)=0.997) and cyanide (R(2)=0.995) were linear and the lower limits of detection for azide and cyanide were 0.1 and 0.3mM, respectively. Several other nucleophiles were identified having no effect on the analysis of azide and cyanide, excepting nitrite which influenced the detection of cyanide. This was the first report of a biological method to determine the inorganic azide and cyanide by converting them to the measurable organics. Copyright © 2015 Elsevier B.V. All rights reserved.

[Effect of DNA-damaging agents on the aerobic methylobacteria capable and incapable of utilizing dichloromethane].

PubMed

Firsova, Iu E; Torgonskaia, M L; Doronina, N V; Trotsenko, Iu A

2005-01-01

Methylobacterium dichloromethanicum DM4, a degrader of dichloromethane (DCM), was more tolerant to the effect of H2O2 and UV irradiation than Methylobacterium extorquens AM1, which does not consume DCM. Addition of CH2Cl2 to methylobacteria with active serine, ribulose monophosphate, and ribulose bisphosphate pathways of C1 metabolism, grown on methanol, resulted in a 1.1- to 2.5-fold increase in the incorporation of [alpha-32P]dATP into DNA Klenow fragment (exo-). As DCM dehalogenase was not induced in this process, the increase in total lengths of DNA gaps resulted from the action of DCM rather than S-chloromethylglutathione (intermediate of primary dehalogenation). The degree of DNA damage in the presence of CH2Cl2 was lower in DCM degraders than methylobacteria incapable of degrading this pollutant. This suggests that DCM degraders possess a more efficient mechanism of DNA repair.

Cobamide-mediated enzymatic reductive dehalogenation via long-range electron transfer

PubMed Central

Kunze, Cindy; Bommer, Martin; Hagen, Wilfred R.; Uksa, Marie; Dobbek, Holger; Schubert, Torsten; Diekert, Gabriele

2017-01-01

The capacity of metal-containing porphyrinoids to mediate reductive dehalogenation is implemented in cobamide-containing reductive dehalogenases (RDases), which serve as terminal reductases in organohalide-respiring microbes. RDases allow for the exploitation of halogenated compounds as electron acceptors. Their reaction mechanism is under debate. Here we report on substrate–enzyme interactions in a tetrachloroethene RDase (PceA) that also converts aryl halides. The shape of PceA’s highly apolar active site directs binding of bromophenols at some distance from the cobalt and with the hydroxyl substituent towards the metal. A close cobalt–substrate interaction is not observed by electron paramagnetic resonance spectroscopy. Nonetheless, a halogen substituent para to the hydroxyl group is reductively eliminated and the path of the leaving halide is traced in the structure. Based on these findings, an enzymatic mechanism relying on a long-range electron transfer is concluded, which is without parallel in vitamin B12-dependent biochemistry and represents an effective mode of RDase catalysis. PMID:28671181

Cobamide-mediated enzymatic reductive dehalogenation via long-range electron transfer.

PubMed

Kunze, Cindy; Bommer, Martin; Hagen, Wilfred R; Uksa, Marie; Dobbek, Holger; Schubert, Torsten; Diekert, Gabriele

2017-07-03

The capacity of metal-containing porphyrinoids to mediate reductive dehalogenation is implemented in cobamide-containing reductive dehalogenases (RDases), which serve as terminal reductases in organohalide-respiring microbes. RDases allow for the exploitation of halogenated compounds as electron acceptors. Their reaction mechanism is under debate. Here we report on substrate-enzyme interactions in a tetrachloroethene RDase (PceA) that also converts aryl halides. The shape of PceA's highly apolar active site directs binding of bromophenols at some distance from the cobalt and with the hydroxyl substituent towards the metal. A close cobalt-substrate interaction is not observed by electron paramagnetic resonance spectroscopy. Nonetheless, a halogen substituent para to the hydroxyl group is reductively eliminated and the path of the leaving halide is traced in the structure. Based on these findings, an enzymatic mechanism relying on a long-range electron transfer is concluded, which is without parallel in vitamin B 12 -dependent biochemistry and represents an effective mode of RDase catalysis.

Microorganisms living on macroalgae: diversity, interactions, and biotechnological applications.

PubMed

Martin, Marjolaine; Portetelle, Daniel; Michel, Gurvan; Vandenbol, Micheline

2014-04-01

Marine microorganisms play key roles in every marine ecological process, hence the growing interest in studying their populations and functions. Microbial communities on algae remain underexplored, however, despite their huge biodiversity and the fact that they differ markedly from those living freely in seawater. The study of this microbiota and of its relationships with algal hosts should provide crucial information for ecological investigations on algae and aquatic ecosystems. Furthermore, because these microorganisms interact with algae in multiple, complex ways, they constitute an interesting source of novel bioactive compounds with biotechnological potential, such as dehalogenases, antimicrobials, and alga-specific polysaccharidases (e.g., agarases, carrageenases, and alginate lyases). Here, to demonstrate the huge potential of alga-associated organisms and their metabolites in developing future biotechnological applications, we first describe the immense diversity and density of these microbial biofilms. We further describe their complex interactions with algae, leading to the production of specific bioactive compounds and hydrolytic enzymes of biotechnological interest. We end with a glance at their potential use in medical and industrial applications.

Crystal Structure of Haloalkane Dehalogenase LinB from Sphingomonas paucimobilis UT26 at 0.95 Å Resolution: Dynamics of Catalytic Residues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oakley, Aaron J.; Klvana, Martin; Otyepka, Michal

We present the structure of LinB, a 33-kDa haloalkane dehalogenase from Sphingomonas paucimobilis UT26, at 0.95 {angstrom} resolution. The data have allowed us to directly observe the anisotropic motions of the catalytic residues. In particular, the side-chain of the catalytic nucleophile, Asp108, displays a high degree of disorder. It has been modeled in two conformations, one similar to that observed previously (conformation A) and one strained (conformation B) that approached the catalytic base (His272). The strain in conformation B was mainly in the C{sub {alpha}}-C{sub {beta}}-C{sub {gamma}} angle (126{sup o}) that deviated by 13.4{sup o} from the 'ideal' bond anglemore » of 112.6{sup o}. On the basis of these observations, we propose a role for the charge state of the catalytic histidine in determining the geometry of the catalytic residues. We hypothesized that double-protonation of the catalytic base (His272) reduces the distance between the side-chain of this residue and that of the Asp108. The results of molecular dynamics simulations were consistent with the structural data showing that protonation of the His272 side-chain nitrogen atoms does indeed reduce the distance between the side-chains of the residues in question, although the simulations failed to demonstrate the same degree of strain in the Asp108 C{sub {alpha}}-C{sub {beta}}-C{sub {gamma}} angle. Instead, the changes in the molecular dynamics structures were distributed over several bond and dihedral angles. Quantum mechanics calculations on LinB with 1-chloro-2,2-dimethylpropane as a substrate were performed to determine which active site conformations and protonation states were most likely to result in catalysis. It was shown that His272 singly protonated at N{sub {delta}1} and Asp108 in conformation A gave the most exothermic reaction ({Delta}H = -22 kcal/mol). With His272 doubly protonated at N{sub {delta}1} and N{sub {epsilon}2}, the reactions were only slightly exothermic or were endothermic. In all calculations starting with Asp108 in conformation B, the Asp108 C{sub {alpha}}-C{sub {beta}}-C{sub {gamma}} angle changed during the reaction and the Asp108 moved to conformation A. The results presented here indicate that the positions of the catalytic residues and charge state of the catalytic base are important for determining reaction energetics in LinB.« less

Marine-Derived Biocatalysts: Importance, Accessing, and Application in Aromatic Pollutant Bioremediation

PubMed Central

Nikolaivits, Efstratios; Dimarogona, Maria; Fokialakis, Nikolas; Topakas, Evangelos

2017-01-01

The aim of the present review is to highlight the potential use of marine biocatalysts (whole cells or enzymes) as an alternative bioprocess for the degradation of aromatic pollutants. Firstly, information about the characteristics of the still underexplored marine environment and the available scientific tools used to access novel marine-derived biocatalysts is provided. Marine-derived enzymes, such as dioxygenases and dehalogenases, and the involved catalytic mechanisms for the degradation of aromatic and halogenated compounds, are presented, with the purpose of underpinning their potential use in bioremediation. Emphasis is given on persistent organic pollutants (POPs) that are organic compounds with significant impact on health and environment due to their resistance in degradation. POPs bioaccumulate mainly in the fatty tissue of living organisms, therefore current efforts are mostly focused on the restriction of their use and production, since their removal is still unclear. A brief description of the guidelines and criteria that render a pollutant POP is given, as well as their potential biodegradation by marine microorganisms by surveying recent developments in this rather unexplored field. PMID:28265269

Enzymes from Extreme Environments and Their Industrial Applications

PubMed Central

Littlechild, Jennifer A.

2015-01-01

This article will discuss the importance of specific extremophilic enzymes for applications in industrial biotechnology. It will specifically address those enzymes that have applications in the area of biocatalysis. Such enzymes now play an important role in catalyzing a variety of chemical conversions that were previously carried out by traditional chemistry. The biocatalytic process is carried out under mild conditions and with greater specificity. The enzyme process does not result in the toxic waste that is usually produced in a chemical process that would require careful disposal. In this sense, the biocatalytic process is referred to as carrying out “green chemistry” which is considered to be environmentally friendly. Some of the extremophilic enzymes to be discussed have already been developed for industrial processes such as an l-aminoacylase and a γ-lactamase. The industrial applications of other extremophilic enzymes, including transaminases, carbonic anhydrases, dehalogenases, specific esterases, and epoxide hydrolases, are currently being assessed. Specific examples of these industrially important enzymes that have been studied in the authors group will be presented in this review. PMID:26528475

A sugar phosphatase regulates the methylerythritol phosphate (MEP) pathway in malaria parasites

PubMed Central

Edwards, Rachel L.; Kelly, Megan L.; Hodge, Dana M.; Tolia, Niraj H.; Odom, Audrey R.

2014-01-01

Isoprenoid biosynthesis through the methylerythritol phosphate (MEP) pathway generates commercially important products and is a target for antimicrobial drug development. MEP pathway regulation is poorly understood in microorganisms. We employ a forward genetics approach to understand MEP pathway regulation in the malaria parasite, Plasmodium falciparum. The antimalarial fosmidomycin inhibits the MEP pathway enzyme deoxyxylulose 5-phosphate reductoisomerase (DXR). Fosmidomycin-resistant P. falciparum are enriched for changes in the PF3D7_1033400 locus (hereafter referred to as PfHAD1), encoding a homologue of haloacid dehalogenase (HAD)-like sugar phosphatases. We describe the structural basis for loss-of-function PfHAD1 alleles and find that PfHAD1 dephosphorylates a variety of sugar phosphates, including glycolytic intermediates. Loss of PfHAD1 is required for fosmidomycin resistance. Parasites lacking PfHAD1 have increased MEP pathway metabolites, particularly the DXR substrate, deoxyxylulose 5-phosphate. PfHAD1 therefore controls substrate availability to the MEP pathway. Because PfHAD1 has homologs in plants and bacteria, other HAD proteins may be MEP pathway regulators. PMID:25058848

Vibrational Stark Effects of Carbonyl Probes Applied to Reinterpret IR and Raman Data for Enzyme Inhibitors in Terms of Electric Fields at the Active Site.

PubMed

Schneider, Samuel H; Boxer, Steven G

2016-09-15

IR and Raman frequency shifts have been reported for numerous probes of enzyme transition states, leading to diverse interpretations. In the case of the model enzyme ketosteroid isomerase (KSI), we have argued that IR spectral shifts for a carbonyl probe at the active site can provide a connection between the active site electric field and the activation free energy (Fried et al. Science 2014, 346, 1510-1514). Here we generalize this approach to a much broader set of carbonyl probes (e.g., oxoesters, thioesters, and amides), first establishing the sensitivity of each probe to an electric field using vibrational Stark spectroscopy, vibrational solvatochromism, and MD simulations, and then applying these results to reinterpret data already in the literature for enzymes such as 4-chlorobenzoyl-CoA dehalogenase and serine proteases. These results demonstrate that the vibrational Stark effect provides a general framework for estimating the electrostatic contribution to the catalytic rate and may provide a metric for the design or modification of enzymes. Opportunities and limitations of the approach are also described.

Valence bond and enzyme catalysis: a time to break down and a time to build up.

PubMed

Sharir-Ivry, Avital; Varatharaj, Rajapandian; Shurki, Avital

2015-05-04

Understanding enzyme catalysis and developing ability to control of it are two great challenges in biochemistry. A few successful examples of computational-based enzyme design have proved the fantastic potential of computational approaches in this field, however, relatively modest rate enhancements have been reported and the further development of complementary methods is still required. Herein we propose a conceptually simple scheme to identify the specific role that each residue plays in catalysis. The scheme is based on a breakdown of the total catalytic effect into contributions of individual protein residues, which are further decomposed into chemically interpretable components by using valence bond theory. The scheme is shown to shed light on the origin of catalysis in wild-type haloalkane dehalogenase (wt-DhlA) and its mutants. Furthermore, the understanding gained through our scheme is shown to have great potential in facilitating the selection of non-optimal sites for catalysis and suggesting effective mutations to enhance the enzymatic rate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of Chloroethylene Dehalogenation by Cell Extracts of Desulfomonile tiedjei and Its Relationship to Chlorobenzoate Dehalogenation

PubMed Central

Townsend, G. T.; Suflita, J. M.

1996-01-01

We characterized the reductive dehalogenation of tetrachloroethylene in cell extracts of Desulfomonile tiedjei and compared it with this organism's 3-chlorobenzoate dehalogenation activity. Tetrachloroethylene was sequentially dehalogenated to trichloro- and dichloroethylene; there was no evidence for dichloroethylene dehalogenation. Like the previously characterized 3-chlorobenzoate dehalogenation activity, tetrachloroethylene dehalogenation was heat sensitive, not oxygen labile, and increased in proportion to the amount of protein in assay mixtures. In addition, both dehalogenation activities were dependent on hydrogen or formate as an electron donor and had an absolute requirement for either methyl viologen or triquat as an electron carrier in vitro. Both activities appear to be catalyzed by integral membrane proteins with similar solubilization characteristics. Dehalogenation of tetrachloroethylene was inhibited by 3-chlorobenzoate but not by the structural isomers 2- and 4-chlorobenzoate. The last two compounds are not substrates for D. tiedjei. These findings lead us to suggest that the dehalogenation of tetrachloroethylene in D. tiedjei is catalyzed by a dehalogenase previously thought to be specific for meta-halobenzoates. PMID:16535377

Efficient Use and Recycling of the Micronutrient Iodide in Mammals

PubMed Central

Rokita, Steven E.; Adler, Jennifer M.; McTamney, Patrick M.; Watson, James A.

2010-01-01

Daily ingestion of iodide alone is not adequate to sustain production of the thyroid hormones, tri- and tetraiodothyronine. Proper maintenance of iodide in vivo also requires its active transport into the thyroid and its salvage from mono- and diiodotyrosine that are formed in excess during hormone biosynthesis. The enzyme iodotyrosine deiodinase responsible for this salvage is unusual in its ability to catalyze a reductive dehalogenation reaction dependent on a flavin cofactor, FMN. Initial characterization of this enzyme was limited by its membrane association, difficult purification and poor stability. The deiodinase became amenable to detailed analysis only after identification and heterologous expression of its gene. Site-directed mutagenesis recently demonstrated that cysteine residues are not necessary for enzymatic activity in contrast to precedence set by other reductive dehalogenases. Truncation of the N-terminal membrane anchor of the deiodinase has provided a soluble and stable source of enzyme sufficient for crystallographic studies. The structure of an enzyme•substrate co-crystal has become invaluable for understanding the origins of substrate selectivity and the mutations causing thyroid disease in humans. PMID:20167242

Binding of anions in triply interlocked coordination catenanes and dynamic allostery for dehalogenation reactions.

PubMed

Yang, Linlin; Jing, Xu; An, Bowen; He, Cheng; Yang, Yang; Duan, Chunying

2018-01-28

By synergistic combination of multicomponent self-assembly and template-directed approaches, triply interlocked metal organic catenanes that consist of two isolated chirally identical tetrahedrons were constructed and stabilized as thermodynamic minima. In the presence of suitable template anions, the structural conversion from the isolated tetrahedral conformers into locked catenanes occurred via the cleavage of an intrinsically reversible coordination bond in each of the tetrahedrons, followed by the reengineering and interlocking of two fragments with the regeneration of the broken coordination bonds. The presence of several kinds of individual pocket that were attributed to the triply interlocked patterns enabled the possibility of encapsulating different anions, allowing the dynamic allostery between the unlocked/locked conformers to promote the dehalogenation reaction of 3-bromo-cyclohexene efficiently, as with the use of dehalogenase enzymes. The interlocked structures could be unlocked into two individual tetrahedrons through removal of the well-matched anion templates. The stability and reversibility of the locked/unlocked structures were further confirmed by the catching/releasing process that accompanied emission switching, providing opportunities for the system to be a dynamic molecular logic system.

Single cell genomic study of Dehalococcoidites in deep sea sediments of Peru Margin 1230

NASA Astrophysics Data System (ADS)

Kaster, A.; Meyer-Blackwell, K.; Spormann, A. M.

2013-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites Dhc were originally discovered as the key microorganisms mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene. Molecular and genomic studies on their key enzymes for energy conservation, reductive dehalogenases rdh, have provided evidence for ubiquitous horizontal gene transfer. A pioneering study by Futagami et al. discovered novel putative rdh phylotypes in sediments from the Pacific, revealing an unknown and surprising abundance of rdh genes in pristine habitats. The frequent detection of Dhc-related 16S rRNA genes from these environments implied the occurrence of dissimilatory dehalorespiration in marine subsurface sediments, however, pristine Dhc could never be linked to this activity. Despite being ubiquitous in those environments, metabolic life style or ecological function of Dhc in the absence of anthropogenic contaminants is still completely unknown. We therefore analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site by a single cell genomic (SGC) approach. We present for the first time data on three single Dhc cells, helping to elucidate their role in the poorly understood oligotrophic marine sub-surface environment.

Electron transport chains in organohalide-respiring bacteria and bioremediation implications.

PubMed

Wang, Shanquan; Qiu, Lan; Liu, Xiaowei; Xu, Guofang; Siegert, Michael; Lu, Qihong; Juneau, Philippe; Yu, Ling; Liang, Dawei; He, Zhili; Qiu, Rongliang

In situ remediation employing organohalide-respiring bacteria represents a promising solution for cleanup of persistent organohalide pollutants. The organohalide-respiring bacteria conserve energy by utilizing H 2 or organic compounds as electron donors and organohalides as electron acceptors. Reductive dehalogenase (RDase), a terminal reductase of the electron transport chain in organohalide-respiring bacteria, is the key enzyme that catalyzes halogen removal. Accumulating experimental evidence thus far suggests that there are distinct models for respiratory electron transfer in organohalide-respirers of different lineages, e.g., Dehalococcoides, Dehalobacter, Desulfitobacterium and Sulfurospirillum. In this review, to connect the knowledge in organohalide-respiratory electron transport chains to bioremediation applications, we first comprehensively review molecular components and their organization, together with energetics of the organohalide-respiratory electron transport chains, as well as recent elucidation of intramolecular electron shuttling and halogen elimination mechanisms of RDases. We then highlight the implications of organohalide-respiratory electron transport chains in stimulated bioremediation. In addition, major challenges and further developments toward understanding the organohalide-respiratory electron transport chains and their bioremediation applications are identified and discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

Novel Dehalogenase Mechanism for 2,3-Dichloro-1-Propanol Utilization in Pseudomonas putida Strain MC4

PubMed Central

Arif, Muhammad Irfan; Samin, Ghufrana; van Leeuwen, Jan G. E.; Oppentocht, Jantien

2012-01-01

A Pseudomonas putida strain (MC4) that can utilize 2,3-dichloro-1-propanol (DCP) and several aliphatic haloacids and haloalcohols as sole carbon and energy source for growth was isolated from contaminated soil. Degradation of DCP was found to start with oxidation and concomitant dehalogenation catalyzed by a 72-kDa monomeric protein (DppA) that was isolated from cell lysate. The dppA gene was cloned from a cosmid library and appeared to encode a protein equipped with a signal peptide and that possessed high similarity to quinohemoprotein alcohol dehydrogenases (ADHs), particularly ADH IIB and ADH IIG from Pseudomonas putida HK. This novel dehalogenating dehydrogenase has a broad substrate range, encompassing a number of nonhalogenated alcohols and haloalcohols. With DCP, DppA exhibited a kcat of 17 s−1. 1H nuclear magnetic resonance experiments indicated that DCP oxidation by DppA in the presence of 2,6-dichlorophenolindophenol (DCPIP) and potassium ferricyanide [K3Fe(CN)6] yielded 2-chloroacrolein, which was oxidized to 2-chloroacrylic acid. PMID:22752160

Degradation pathway of 2-chloroethanol in Pseudomonas stutzeri strain JJ under denitrifying conditions.

PubMed

Dijk, John A; Gerritse, Jan; Schraa, Gosse; Stams, Alfons J M

2004-12-01

The pathway of 2-chloroethanol degradation in the denitrifying Pseudomonas stutzeri strain JJ was investigated. In cell-free extracts, activities of a phenazine methosulfate (PMS)-dependent chloroethanol dehydrogenase, an NAD-dependent chloroacetaldehyde dehydrogenase, and a chloroacetate dehalogenase were detected. This suggested that the 2-chloroethanol degradation pathway in this denitrifying strain is the same as found in aerobic bacteria that degrade chloroethanol. Activity towards primary alcohols, secondary alcohols, diols, and other chlorinated alcohols could be measured in cell-free extracts with chloroethanol dehydrogenase (CE-DH) activity. PMS and phenazine ethosulfate (PES) were used as primary electron acceptors, but not NAD, NADP or ferricyanide. Cells of strain JJ cultured in a continuous culture under nitrate limitation exhibited chloroethanol dehydrogenase activity that was a 12 times higher than in cells grown in batch culture. However, under chloroethanol-limiting conditions, CE-DH activity was in the same range as in batch culture. Cells grown on ethanol did not exhibit CE-DH activity. Instead, NAD-dependent ethanol dehydrogenase (E-DH) activity and PMS-dependent E-DH activity were detected.

Directed evolution of enzymes using microfluidic chips

NASA Astrophysics Data System (ADS)

Pilát, Zdeněk.; Ježek, Jan; Šmatlo, Filip; Kaůka, Jan; Zemánek, Pavel

2016-12-01

Enzymes are highly versatile and ubiquitous biological catalysts. They can greatly accelerate large variety of reactions, while ensuring appropriate catalytic activity and high selectivity. These properties make enzymes attractive biocatalysts for a wide range of industrial and biomedical applications. Over the last two decades, directed evolution of enzymes has transformed the field of protein engineering. We have devised microfluidic systems for directed evolution of haloalkane dehalogenases in emulsion droplets. In such a device, individual bacterial cells producing mutated variants of the same enzyme are encapsulated in microdroplets and supplied with a substrate. The conversion of a substrate by the enzyme produced by a single bacterium changes the pH in the droplet which is signalized by pH dependent fluorescence probe. The droplets with the highest enzymatic activity can be separated directly on the chip by dielectrophoresis and the resultant cell lineage can be used for enzyme production or for further rounds of directed evolution. This platform is applicable for fast screening of large libraries in directed evolution experiments requiring mutagenesis at multiple sites of a protein structure.

Single cell genomic study of dehalogenating Chloroflexi from deep sea sediments of Peruvian Margin

NASA Astrophysics Data System (ADS)

Spormann, A.; Kaster, A.; Meyer-Blackwell, K.; Biddle, J.

2012-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites (Dhc), are members of the rare biosphere of deep sea sediments but were originally discovered as the key microbes mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene to ethene. Dhc are slow growing, highly niche adapted microbes that are specialized to organohalide respiration as the sole mode of energy conservation. These strictly anaerobic microbes depend on a supporting microbial community to mitigate electron donor and cofactor requirements among other factors. Molecular and genomic studies on the key enzymes for energy conservation, reductive dehalogenases, have provided evidence for rapid adaptive evolution in terrestrial environments. However, the metabolic life style of Dhc in the absence of anthropogenic contaminants, such as in pristine deep sea sediments, is still unknown. In order to provide fundamental insights into life style, genomic population structure and evolution of Dhc, we analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site collected 6 mbf by a metagenomic and single cell genomic. We present for the first time single cell genomic data on dehalogenating Chloroflexi, a significant microbial population in the poorly understood oligotrophic marine sub-surface environments.

Single cell genomic study of dehalogenating Chloroflexi in deep sea sediments of Peru Margin 1230

NASA Astrophysics Data System (ADS)

Kaster, A.; Meyer-Blackwell, K.; Biddle, J.; Spormann, A.

2012-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites (Dhc), are members of the rare biosphere of deep sea sediments but were originally discovered as the key microbes mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene to ethene. Dhc are slow growing, highly niche adapted microbes that are specialized to organohalide respiration as the sole mode of energy conservation. They are strictly anaerobic microbes that depend on a supporting microbial community for electron donor and cofactor requirements among other factors. Molecular and genomic studies on the key enzymes for energy conservation, reductive dehalogenases, have provided evidence for rapid adaptive evolution in terrestrial environments. However, the metabolic life style of Dhc in the absence of anthropogenic contaminants, such as in pristine deep sea sediments, is still unknown. In order to provide fundamental insights into life style, genomic population structure and evolution of Dhc, we analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site collected 6 mbsf by a metagenomic and single cell genomic approach. We present for the first time single cell genomic data on dehalogenating Chloroflexi, a significant microbial population in the poorly understood oligotrophic marine sub-surface environment.

Reductive dehalogenation of 3,5-dibromo-4-hydroxybenzoate by an aerobic strain of Delftia sp. EOB-17.

PubMed

Chen, Kai; Jian, Shanshan; Huang, Linglong; Ruan, Zhepu; Li, Shunpeng; Jiang, Jiandong

2015-12-01

To confirm the reductive dehalogenation ability of the aerobic strain of Delftia sp. EOB-17, finding more evidences to support the hypothesis that reductive dehalogenation may occur extensively in aerobic bacteria. Delftia sp. EOB-17, isolated from terrestrial soil contaminated with halogenated aromatic compounds, completely degraded 0.2 mM DBHB in 28 h and released two equivalents of bromides under aerobic conditions in the presence of sodium succinate. LC-MS analysis revealed that DBHB was transformed to 4-hydroxybenzoate via 3-bromo-4-hydroxybenzoate by successive reductive dehalogenation. Highly conserved DBHB-degrading genes, including reductive dehalogenase gene (bhbA3) and the extra-cytoplasmic binding receptor gene (bhbB3), were also found in strain EOB-17 by genome sequencing. The optimal temperature and pH for DBHB reductive dehalogenation activity are 30 °C and 8, respectively, and 0.1 mM Cd(2+), Cu(2+), Hg(2+) and Zn(2+) strongly inhibited dehalogenation activity. The aerobic strain of Delftia sp. EOB-17 was confirmed to reductively dehalogenate DBHB under aerobic conditions, providing another evidence to support the hypothesis that reductive dehalogenation occurs extensively in aerobic bacteria.

Proteomics of the organohalide-respiring Epsilonproteobacterium Sulfurospirillum multivorans adapted to tetrachloroethene and other energy substrates

PubMed Central

Goris, Tobias; Schiffmann, Christian L.; Gadkari, Jennifer; Schubert, Torsten; Seifert, Jana; Jehmlich, Nico; von Bergen, Martin; Diekert, Gabriele

2015-01-01

Organohalide respiration is an environmentally important but poorly characterized type of anaerobic respiration. We compared the global proteome of the versatile organohalide-respiring Epsilonproteobacterium Sulfurospirillum multivorans grown with different electron acceptors (fumarate, nitrate, or tetrachloroethene [PCE]). The most significant differences in protein abundance were found for gene products of the organohalide respiration region. This genomic region encodes the corrinoid and FeS cluster containing PCE reductive dehalogenase PceA and other proteins putatively involved in PCE metabolism such as those involved in corrinoid biosynthesis. The latter gene products as well as PceA and a putative quinol dehydrogenase were almost exclusively detected in cells grown with PCE. This finding suggests an electron flow from the electron donor such as formate or pyruvate via the quinone pool and a quinol dehydrogenase to PceA and the terminal electron acceptor PCE. Two putative accessory proteins, an IscU-like protein and a peroxidase-like protein, were detected with PCE only and might be involved in PceA maturation. The proteome of cells grown with pyruvate instead of formate as electron donor indicates a route of electrons from reduced ferredoxin via an Epsilonproteobacterial complex I and the quinone pool to PCE. PMID:26387727

Metabolomics of hexachlorocyclohexane (HCH) transformation: ratio of LinA to LinB determines metabolic fate of HCH isomers.

PubMed

Geueke, Birgit; Garg, Nidhi; Ghosh, Sneha; Fleischmann, Thomas; Holliger, Christof; Lal, Rup; Kohler, Hans-Peter E

2013-04-01

Although the production and use of technical hexachlorocyclohexane (HCH) and lindane (the purified insecticidal isomer γ-HCH) are prohibited in most countries, residual concentrations still constitute an immense environmental burden. Many studies describe the mineralization of γ-HCH by bacterial strains under aerobic conditions. However, the metabolic fate of the other HCH isomers is not well known. In this study, we investigated the transformation of α-, β-, γ-, δ-, ε-HCH, and a heptachlorocyclohexane isomer in the presence of varying ratios of the two enzymes that initiate γ-HCH degradation, a dehydrochlorinase (LinA) and a haloalkane dehalogenase (LinB). Each substrate yielded a unique metabolic profile that was strongly dependent on the enzyme ratio. Comparison of these results to those of in vivo experiments with different bacterial isolates showed that HCH transformation in the tested strains was highly optimized towards productive metabolism of γ-HCH and that under these conditions other HCH-isomers were metabolized to mixtures of dehydrochlorinated and hydroxylated side-products. In view of these results, bioremediation efforts need very careful planning and toxicities of accumulating metabolites need to be evaluated. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

FireProt: Energy- and Evolution-Based Computational Design of Thermostable Multiple-Point Mutants.

PubMed

Bednar, David; Beerens, Koen; Sebestova, Eva; Bendl, Jaroslav; Khare, Sagar; Chaloupkova, Radka; Prokop, Zbynek; Brezovsky, Jan; Baker, David; Damborsky, Jiri

2015-11-01

There is great interest in increasing proteins' stability to enhance their utility as biocatalysts, therapeutics, diagnostics and nanomaterials. Directed evolution is a powerful, but experimentally strenuous approach. Computational methods offer attractive alternatives. However, due to the limited reliability of predictions and potentially antagonistic effects of substitutions, only single-point mutations are usually predicted in silico, experimentally verified and then recombined in multiple-point mutants. Thus, substantial screening is still required. Here we present FireProt, a robust computational strategy for predicting highly stable multiple-point mutants that combines energy- and evolution-based approaches with smart filtering to identify additive stabilizing mutations. FireProt's reliability and applicability was demonstrated by validating its predictions against 656 mutations from the ProTherm database. We demonstrate that thermostability of the model enzymes haloalkane dehalogenase DhaA and γ-hexachlorocyclohexane dehydrochlorinase LinA can be substantially increased (ΔTm = 24°C and 21°C) by constructing and characterizing only a handful of multiple-point mutants. FireProt can be applied to any protein for which a tertiary structure and homologous sequences are available, and will facilitate the rapid development of robust proteins for biomedical and biotechnological applications.

Functional genomics of corrinoid starvation in the organohalide-respiring bacterium Dehalobacter restrictus strain PER-K23

PubMed Central

Rupakula, Aamani; Lu, Yue; Kruse, Thomas; Boeren, Sjef; Holliger, Christof; Smidt, Hauke; Maillard, Julien

2015-01-01

De novo corrinoid biosynthesis represents one of the most complicated metabolic pathways in nature. Organohalide-respiring bacteria (OHRB) have developed different strategies to deal with their need of corrinoid, as it is an essential cofactor of reductive dehalogenases, the key enzymes in OHR metabolism. In contrast to Dehalococcoides mccartyi, the genome of Dehalobacter restrictus strain PER-K23 contains a complete set of corrinoid biosynthetic genes, of which cbiH appears to be truncated and therefore non-functional, possibly explaining the corrinoid auxotrophy of this obligate OHRB. Comparative genomics within Dehalobacter spp. revealed that one (operon-2) of the five distinct corrinoid biosynthesis associated operons present in the genome of D. restrictus appeared to be present only in that particular strain, which encodes multiple members of corrinoid transporters and salvaging enzymes. Operon-2 was highly up-regulated upon corrinoid starvation both at the transcriptional (346-fold) and proteomic level (46-fold on average), in line with the presence of an upstream cobalamin riboswitch. Together, these data highlight the importance of this operon in corrinoid homeostasis in D. restrictus and the augmented salvaging strategy this bacterium adopted to cope with the need for this essential cofactor. PMID:25610435

Genetically encoded multispectral labeling of proteins with polyfluorophores on a DNA backbone.

PubMed

Singh, Vijay; Wang, Shenliang; Chan, Ke Min; Clark, Spencer A; Kool, Eric T

2013-04-24

Genetically encoded methods for protein conjugation are of high importance as biological tools. Here we describe the development of a new class of dyes for genetically encoded tagging that add new capabilities for protein reporting and detection via HaloTag methodology. Oligodeoxyfluorosides (ODFs) are short DNA-like oligomers in which the natural nucleic acid bases are replaced by interacting fluorescent chromophores, yielding a broad range of emission colors using a single excitation wavelength. We describe the development of an alkyl halide dehalogenase-compatible chloroalkane linker phosphoramidite derivative that enables the rapid automated synthesis of many possible dyes for protein conjugation. Experiments to test the enzymatic self-conjugation of nine different DNA-like dyes to proteins with HaloTag domains in vitro were performed, and the data confirmed the rapid and efficient covalent labeling of the proteins. Notably, a number of the ODF dyes were found to increase in brightness or change color upon protein conjugation. Tests in mammalian cellular settings revealed that the dyes are functional in multiple cellular contexts, both on the cell surface and within the cytoplasm, allowing protein localization to be imaged in live cells by epifluorescence and laser confocal microscopy.

Mechanistic insights into the dehalogenation reaction of fluoroacetate/fluoroacetic acid

NASA Astrophysics Data System (ADS)

Miranda-Rojas, Sebastián; Toro-Labbé, Alejandro

2015-05-01

Fluoroacetate is a toxic compound whose environmental accumulation may represent an important contamination problem, its elimination is therefore a challenging issue. Fluoroacetate dehalogenase catalyzes its degradation through a two step process initiated by an SN2 reaction in which the aspartate residue performs a nucleophilic attack on the carbon bonded to the fluorine; the second step is hydrolysis that releases the product as glycolate. In this paper, we present a study based on density functional theory calculations of the SN2 initiation reaction modeled through the interaction between the substrate and the propionate anion as the nucleophile. Results are analyzed within the framework of the reaction force and using the reaction electronic flux to identify and characterize the electronic activity that drives the reaction. Our results reveal that the selective protonation of the substrate catalyzes the reaction by decreasing the resistance of the structural and electronic reorganization needed to reach the transition state. Finally, the reaction energy is modulated by the degree of stabilization of the fluoride anion formed after the SN2 reaction. In this way, a site-induced partial protonation acts as a chemical switch in a key process that determines the output of the reaction.

A 13-week research-based biochemistry laboratory curriculum.

PubMed

Lefurgy, Scott T; Mundorff, Emily C

2017-09-01

Here, we present a 13-week research-based biochemistry laboratory curriculum designed to provide the students with the experience of engaging in original research while introducing foundational biochemistry laboratory techniques. The laboratory experience has been developed around the directed evolution of an enzyme chosen by the instructor, with mutations designed by the students. Ideal enzymes for this curriculum are able to be structurally modeled, solubly expressed, and monitored for activity by UV/Vis spectroscopy, and an example curriculum for haloalkane dehalogenase is given. Unique to this curriculum is a successful implementation of saturation mutagenesis and high-throughput screening of enzyme function, along with bioinformatics analysis, homology modeling, structural analysis, protein expression and purification, polyacrylamide gel electrophoresis, UV/Vis spectroscopy, and enzyme kinetics. Each of these techniques is carried out using a novel student-designed mutant library or enzyme variant unique to the lab team and, importantly, not described previously in the literature. Use of a well-established set of protocols promotes student data quality. Publication may result from the original student-generated hypotheses and data, either from the class as a whole or individual students that continue their independent projects upon course completion. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(5):437-448, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

Application of bioinformatics tools and databases in microbial dehalogenation research (a review).

PubMed

Satpathy, R; Konkimalla, V B; Ratha, J

2015-01-01

Microbial dehalogenation is a biochemical process in which the halogenated substances are catalyzed enzymatically in to their non-halogenated form. The microorganisms have a wide range of organohalogen degradation ability both explicit and non-specific in nature. Most of these halogenated organic compounds being pollutants need to be remediated; therefore, the current approaches are to explore the potential of microbes at a molecular level for effective biodegradation of these substances. Several microorganisms with dehalogenation activity have been identified and characterized. In this aspect, the bioinformatics plays a key role to gain deeper knowledge in this field of dehalogenation. To facilitate the data mining, many tools have been developed to annotate these data from databases. Therefore, with the discovery of a microorganism one can predict a gene/protein, sequence analysis, can perform structural modelling, metabolic pathway analysis, biodegradation study and so on. This review highlights various methods of bioinformatics approach that describes the application of various databases and specific tools in the microbial dehalogenation fields with special focus on dehalogenase enzymes. Attempts have also been made to decipher some recent applications of in silico modeling methods that comprise of gene finding, protein modelling, Quantitative Structure Biodegradibility Relationship (QSBR) study and reconstruction of metabolic pathways employed in dehalogenation research area.

Biodegradation of 2,4'-dichlorobiphenyl, a congener of polychlorinated biphenyl, by Pseudomonas isolates GSa and GSb.

PubMed

Gayathri, D; Shobha, K J

2015-08-01

Bioegradation of 2,4'-dichlorobiphenyl (2,4 CB), by two isolates of Pseudomonas (GSa and GSb) was compared using GC-MS. Transformer oil polluted soil was used for the isolation of 2,4 CB degrading bacteria. GC-MS analysis of the solvent extracts obtained from Pseudomonas sp. GSa spent culture indicated the presence of Phenol 2,6-bis (1,1-dimethyl)-4-methyl (C15H24O). Further, the enzyme analysis of the cell free extracts showed the presence of 2,4'-dichlorobiphenyl dehalogenase (CBD), 2,4'-dichlorobiphenyl-NADPH-oxido-reductase (2,4 CBOR) and 2,3-dihydroxybiphenyl-NADPH-oxido-reductase (2,3 DHOR) with specific activity of 6.00, 0.4 and 0.22 pmol/min/mg of protein, suggesting that dechlorination as an important step during 2,4 CB catabolism. Further, the cell free extract of GSb showed only 2,4'-dichlorobiphenyl-NADPH-oxido-reductase (2,4 CBOR) and 2,3-dihydroxybiphenyl-NADPH-oxido-reductase (2,3 DHOR), with specific activity of 0.3 and 0.213 μmol/min/mg of protein, suggesting attack on non-chlorinated aromatic ring of 2,4 CB, releasing chlorinated intermediates which are toxic to the environment. Although, both the isolated bacteria (GSa and GSb) belong to Pseudomonas spp., they exhibited different metabolic potential.

MDC-Analyzer: a novel degenerate primer design tool for the construction of intelligent mutagenesis libraries with contiguous sites.

PubMed

Tang, Lixia; Wang, Xiong; Ru, Beibei; Sun, Hengfei; Huang, Jian; Gao, Hui

2014-06-01

Recent computational and bioinformatics advances have enabled the efficient creation of novel biocatalysts by reducing amino acid variability at hot spot regions. To further expand the utility of this strategy, we present here a tool called Multi-site Degenerate Codon Analyzer (MDC-Analyzer) for the automated design of intelligent mutagenesis libraries that can completely cover user-defined randomized sequences, especially when multiple contiguous and/or adjacent sites are targeted. By initially defining an objective function, the possible optimal degenerate PCR primer profiles could be automatically explored using the heuristic approach of Greedy Best-First-Search. Compared to the previously developed DC-Analyzer, MDC-Analyzer allows for the existence of a small amount of undesired sequences as a tradeoff between the number of degenerate primers and the encoded library size while still providing all the benefits of DC-Analyzer with the ability to randomize multiple contiguous sites. MDC-Analyzer was validated using a series of randomly generated mutation schemes and experimental case studies on the evolution of halohydrin dehalogenase, which proved that the MDC methodology is more efficient than other methods and is particularly well-suited to exploring the sequence space of proteins using data-driven protein engineering strategies.

A tiered approach to evaluate an iodine recycling inhibition ...

EPA Pesticide Factsheets

The enzyme iodotyrosine deiodinase (dehalogenase, IYD) catalyzes iodide recycling and promotes iodide retention in thyroid follicular cells. Loss of function or chemical inhibition of IYD reduces thyroid hormone synthesis, which leads to insufficiency in tissues and subsequent negative developmental consequences. Iodide recycling by IYD is especially critical for low iodine diets and low iodine environments, including most freshwater ecosystems. We developed a putative adverse outcome pathway for IYD inhibition in amphibians and evaluated IYD inhibition with a tiered approach: 1) development of an in vitro IYD enzyme inhibition assay for chemical screening of compounds of interest to the US EPA, 2) ex vivo thyroid culture to establish thyroglobulin iodination as a biomarker of IYD inhibition, and 3) in vivo bioassays to characterize an organismal adverse outcome and test essentiality of IYD activity. An in vitro colorimetric assay was developed to measure activity of recombinant human IYD enzyme in a 96-well format, establishing the feasibility of medium to high throughput screening of chemicals for IYD inhibition. In ex vivo thyroid culture studies, thyroxine (T4), monoiodotyrosine (MIT), and diiodotyrosine (DIT) were quantified in individual thyroid glands and the media using a ultrahigh performance LC-MS/MS. In vivo exposure of developing Xenopus laevis to a suspected IYD inhibitor (3-L-nitro-tyrosine) resulted in markedly delayed metamorphosis and glandular

Sulfobacillus thermosulfidooxidans strain Cutipay enhances chalcopyrite bioleaching under moderate thermophilic conditions in the presence of chloride ion.

PubMed

Bobadilla-Fazzini, Roberto A; Cortés, Maria Paz; Maass, Alejandro; Parada, Pilar

2014-12-01

Currently more than 90% of the world's copper is obtained through sulfide mineral processing. Among the copper sulfides, chalcopyrite is the most abundant and therefore economically relevant. However, primary copper sulfide bioleaching is restricted due to high ionic strength raffinate solutions and particularly chloride coming from the dissolution of ores. In this work we describe the chalcopyrite bioleaching capacity of Sulfobacillus thermosulfidooxidans strain Cutipay (DSM 27601) previously described at the genomic level (Travisany et al. (2012) Draft genome sequence of the Sulfobacillus thermosulfidooxidans Cutipay strain, an indigenous bacterium isolated from a naturally extreme mining environment in Northern Chile. J Bacteriol 194:6327-6328). Bioleaching assays with the mixotrophic strain Cutipay showed a strong increase in copper recovery from chalcopyrite concentrate at 50°C in the presence of chloride ion, a relevant inhibitory element present in copper bioleaching processes. Compared to the abiotic control and a test with Sulfobacillus acidophilus DSM 10332, strain Cutipay showed an increase of 42 and 69% in copper recovery, respectively, demonstrating its high potential for chalcopyrite bioleaching. Moreover, a genomic comparison highlights the presence of the 2-Haloacid dehalogenase predicted-protein related to a potential new mechanism of chloride resistance in acidophiles. This novel and industrially applicable strain is under patent application CL 2013-03335.

Identification and characterization of a gene encoding for a nucleotidase from Phaseolus vulgaris.

PubMed

Cabello-Díaz, Juan Miguel; Gálvez-Valdivieso, Gregorio; Caballo, Cristina; Lambert, Rocío; Quiles, Francisco Antonio; Pineda, Manuel; Piedras, Pedro

2015-08-01

Nucleotidases are phosphatases that catalyze the removal of phosphate from nucleotides, compounds with an important role in plant metabolism. A phosphatase enzyme, with high affinity for nucleotides monophosphate previously identified and purified in embryonic axes from French bean, has been analyzed by MALDI TOF/TOF and two internal peptides have been obtained. The information of these peptide sequences has been used to search in the genome database and only a candidate gene that encodes for the phosphatase was identified (PvNTD1). The putative protein contains the conserved domains (motif I-IV) for haloacid dehalogenase-like hydrolases superfamily. The residues involved in the catalytic activity are also conserved. A recombinant protein overexpressed in Escherichia coli has shown molybdate resistant phosphatase activity with nucleosides monophosphate as substrate, confirming that the identified gene encodes for the phosphatase with high affinity for nucleotides purified in French bean embryonic axes. The activity of the purified protein was inhibited by adenosine. The expression of PvNTD1 gene was induced at the specific moment of radicle protrusion in embryonic axes. The gene was also highly expressed in young leaves whereas the level of expression in mature tissues was minimal. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.

Distribution of dehalogenation activity in subseafloor sediments of the Nankai Trough subduction zone

PubMed Central

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H.; Inagaki, Fumio

2013-01-01

Halogenated organic matter buried in marine subsurface sediment may serve as a source of electron acceptors for anaerobic respiration of subseafloor microbes. Detection of a diverse array of reductive dehalogenase-homologous (rdhA) genes suggests that subseafloor organohalide-respiring microbial communities may play significant ecological roles in the biogeochemical carbon and halogen cycle in the subseafloor biosphere. We report here the spatial distribution of dehalogenation activity in the Nankai Trough plate-subduction zone of the northwest Pacific off the Kii Peninsula of Japan. Incubation experiments with slurries of sediment collected at various depths and locations showed that degradation of several organohalides tested only occurred in the shallow sedimentary basin, down to 4.7 metres below the seafloor, despite detection of rdhA in the deeper sediments. We studied the phylogenetic diversity of the metabolically active microbes in positive enrichment cultures by extracting RNA, and found that Desulfuromonadales bacteria predominate. In addition, for the isolation of genes involved in the dehalogenation reaction, we performed a substrate-induced gene expression screening on DNA extracted from the enrichment cultures. Diverse DNA fragments were obtained and some of them showed best BLAST hit to known organohalide respirers such as Dehalococcoides, whereas no functionally known dehalogenation-related genes such as rdhA were found, indicating the need to improve the molecular approach to assess functional genes for organohalide respiration. PMID:23479745

Binding of anions in triply interlocked coordination catenanes and dynamic allostery for dehalogenation reactions† †Electronic supplementary information (ESI) available: Characterization data and additional tables and figures. CCDC 1515722 and 1515723. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc04070a

PubMed Central

Yang, Linlin; Jing, Xu; An, Bowen; Yang, Yang

2017-01-01

By synergistic combination of multicomponent self-assembly and template-directed approaches, triply interlocked metal organic catenanes that consist of two isolated chirally identical tetrahedrons were constructed and stabilized as thermodynamic minima. In the presence of suitable template anions, the structural conversion from the isolated tetrahedral conformers into locked catenanes occurred via the cleavage of an intrinsically reversible coordination bond in each of the tetrahedrons, followed by the reengineering and interlocking of two fragments with the regeneration of the broken coordination bonds. The presence of several kinds of individual pocket that were attributed to the triply interlocked patterns enabled the possibility of encapsulating different anions, allowing the dynamic allostery between the unlocked/locked conformers to promote the dehalogenation reaction of 3-bromo-cyclohexene efficiently, as with the use of dehalogenase enzymes. The interlocked structures could be unlocked into two individual tetrahedrons through removal of the well-matched anion templates. The stability and reversibility of the locked/unlocked structures were further confirmed by the catching/releasing process that accompanied emission switching, providing opportunities for the system to be a dynamic molecular logic system. PMID:29675152

Distribution of dehalogenation activity in subseafloor sediments of the Nankai Trough subduction zone.

PubMed

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H; Inagaki, Fumio

2013-04-19

Halogenated organic matter buried in marine subsurface sediment may serve as a source of electron acceptors for anaerobic respiration of subseafloor microbes. Detection of a diverse array of reductive dehalogenase-homologous (rdhA) genes suggests that subseafloor organohalide-respiring microbial communities may play significant ecological roles in the biogeochemical carbon and halogen cycle in the subseafloor biosphere. We report here the spatial distribution of dehalogenation activity in the Nankai Trough plate-subduction zone of the northwest Pacific off the Kii Peninsula of Japan. Incubation experiments with slurries of sediment collected at various depths and locations showed that degradation of several organohalides tested only occurred in the shallow sedimentary basin, down to 4.7 metres below the seafloor, despite detection of rdhA in the deeper sediments. We studied the phylogenetic diversity of the metabolically active microbes in positive enrichment cultures by extracting RNA, and found that Desulfuromonadales bacteria predominate. In addition, for the isolation of genes involved in the dehalogenation reaction, we performed a substrate-induced gene expression screening on DNA extracted from the enrichment cultures. Diverse DNA fragments were obtained and some of them showed best BLAST hit to known organohalide respirers such as Dehalococcoides, whereas no functionally known dehalogenation-related genes such as rdhA were found, indicating the need to improve the molecular approach to assess functional genes for organohalide respiration.

Reductive dehalogenation activity of indigenous microorganism in sediments of the Hackensack River, New Jersey.

PubMed

Sohn, Seo Yean; Häggblom, Max M

2016-07-01

Organohalogen pollutants are of concern in many river and estuarine environments, such as the New York-New Jersey Harbor estuary and its tributaries. The Hackensack River is contaminated with various metals, hydrocarbons and halogenated organics, including polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins. In order to examine the potential for microbial reductive dechlorination by indigenous microorganisms, sediment samples were collected from five different estuarine locations along the Hackensack River. Hexachlorobenzene (HCB), hexabromobenzene (HBB), and pentachloroaniline (PCA) were selected as model organohalogen pollutants to assess anaerobic dehalogenating potential. Dechlorinating activity of HCB and PCA was observed in sediment microcosms for all sampling sites. HCB was dechlorinated via pentachlorobenzene (PeCB) and trichlorobenzene (TriCB) to dichlorobenzene (DCB). PCA was dechlorinated via tetrachloroaniline (TeCA), trichloroanilines (TriCA), and dichloroanilines (DCA) to monochloroaniline (MCA). No HBB debromination was observed over 12 months of incubation. However, with HCB as a co-substrate slow HBB debromination was observed with production of tetrabromobenzene (TeBB) and tribromobenzene (TriBB). Chloroflexi specific 16S rRNA gene PCR-DGGE followed by sequence analysis detected Dehalococcoides species in sediments of the freshwater location, but not in the estuarine site. Analysis targeting 12 putative reductive dehalogenase (rdh) genes showed that these were enriched concomitant with HCB or PCA dechlorination in freshwater sediment microcosms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reductive tetrachloroethene dehalogenation in the presence of oxygen by Sulfurospirillum multivorans: physiological studies and proteome analysis.

PubMed

Gadkari, Jennifer; Goris, Tobias; Schiffmann, Christian L; Rubick, Raffael; Adrian, Lorenz; Schubert, Torsten; Diekert, Gabriele

2018-01-01

Reductive dehalogenation of organohalides is carried out by organohalide-respiring bacteria (OHRB) in anoxic environments. The tetrachloroethene (PCE)-respiring Epsilonproteobacterium Sulfurospirillum multivorans is one of few OHRB able to respire oxygen. Therefore, we investigated the organism's capacity to dehalogenate PCE in the presence of oxygen, which would broaden the applicability to use S. multivorans, unlike other commonly oxygen-sensitive OHRB, for bioremediation, e.g. at oxic/anoxic interphases. Additionally, this has an impact on our understanding of the global halogen cycle. Sulfurospirillum multivorans performs dehalogenation of PCE to cis-1,2-dichloroethene at oxygen concentrations below 0.19 mg/L. The redox potential of the medium electrochemically adjusted up to +400 mV had no influence on reductive dehalogenation by S. multivorans in our experiments, suggesting that higher levels of oxygen impair PCE dechlorination by inhibiting or inactivating involved enzymes. The PCE reductive dehalogenase remained active in cell extracts of S. multivorans exposed to 0.37 mg/L oxygen for more than 96 h. Analysis of the proteome revealed that superoxide reductase and cytochrome peroxidase amounts increased with 5% oxygen in the gas phase, while the response to atmospheric oxygen concentrations involved catalase and hydrogen peroxide reductase. Taken together, our results demonstrate that reductive dehalogenation by OHRB is not limited to anoxic conditions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Characterization of key triacylglycerol biosynthesis processes in rhodococci

DOE PAGES

Amara, Sawsan; Seghezzi, Nicolas; Otani, Hiroshi; ...

2016-04-29

In this study, oleaginous microorganisms have considerable potential for biofuel and commodity chemical production. Under nitrogen-limitation, Rhodococcus jostii RHA1 grown on benzoate, an analog of lignin depolymerization products, accumulated triacylglycerols (TAGs) to 55% of its dry weight during transition to stationary phase, with the predominant fatty acids being C16:0 and C17:0. Transcriptomic analyses of RHA1 grown under conditions of N-limitation and N-excess revealed 1,826 dysregulated genes. Genes whose transcripts were more abundant under N-limitation included those involved in ammonium assimilation, benzoate catabolism, fatty acid biosynthesis and the methylmalonyl-CoA pathway. Of the 16 atf genes potentially encoding diacylglycerol O-acyltransferases, atf8 transcriptsmore » were the most abundant during N-limitation (~50-fold more abundant than during N-excess). Consistent with Atf8 being a physiological determinant of TAG accumulation, a Δ atf8 mutant accumulated 70% less TAG than wild-type RHA1 while atf8 overexpression increased TAG accumulation 20%. Genes encoding type-2 phosphatidic acid phosphatases were not significantly expressed. By contrast, three genes potentially encoding phosphatases of the haloacid dehalogenase superfamily and that cluster with, or are fused with other Kennedy pathway genes were dysregulated. Overall, these findings advance our understanding of TAG metabolism in mycolic acid-containing bacteria and provide a framework to engineer strains for increased TAG production.« less

Characterization of key triacylglycerol biosynthesis processes in rhodococci

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amara, Sawsan; Seghezzi, Nicolas; Otani, Hiroshi

In this study, oleaginous microorganisms have considerable potential for biofuel and commodity chemical production. Under nitrogen-limitation, Rhodococcus jostii RHA1 grown on benzoate, an analog of lignin depolymerization products, accumulated triacylglycerols (TAGs) to 55% of its dry weight during transition to stationary phase, with the predominant fatty acids being C16:0 and C17:0. Transcriptomic analyses of RHA1 grown under conditions of N-limitation and N-excess revealed 1,826 dysregulated genes. Genes whose transcripts were more abundant under N-limitation included those involved in ammonium assimilation, benzoate catabolism, fatty acid biosynthesis and the methylmalonyl-CoA pathway. Of the 16 atf genes potentially encoding diacylglycerol O-acyltransferases, atf8 transcriptsmore » were the most abundant during N-limitation (~50-fold more abundant than during N-excess). Consistent with Atf8 being a physiological determinant of TAG accumulation, a Δ atf8 mutant accumulated 70% less TAG than wild-type RHA1 while atf8 overexpression increased TAG accumulation 20%. Genes encoding type-2 phosphatidic acid phosphatases were not significantly expressed. By contrast, three genes potentially encoding phosphatases of the haloacid dehalogenase superfamily and that cluster with, or are fused with other Kennedy pathway genes were dysregulated. Overall, these findings advance our understanding of TAG metabolism in mycolic acid-containing bacteria and provide a framework to engineer strains for increased TAG production.« less

A conserved tryptophan within the WRDPLVDID domain of yeast Pah1 phosphatidate phosphatase is required for its in vivo function in lipid metabolism.

PubMed

Park, Yeonhee; Han, Gil-Soo; Carman, George M

2017-12-01

PAH1 -encoded phosphatidate phosphatase, which catalyzes the dephosphorylation of phosphatidate to produce diacylglycerol at the endoplasmic reticulum membrane, plays a major role in controlling the utilization of phosphatidate for the synthesis of triacylglycerol or membrane phospholipids. The conserved N-LIP and haloacid dehalogenase-like domains of Pah1 are required for phosphatidate phosphatase activity and the in vivo function of the enzyme. Its non-conserved regions, which are located between the conserved domains and at the C terminus, contain sites for phosphorylation by multiple protein kinases. Truncation analyses of the non-conserved regions showed that they are not essential for the catalytic activity of Pah1 and its physiological functions ( e.g. triacylglycerol synthesis). This analysis also revealed that the C-terminal region contains a previously unrecognized WRDPLVDID domain (residues 637-645) that is conserved in yeast, mice, and humans. The deletion of this domain had no effect on the catalytic activity of Pah1 but caused the loss of its in vivo function. Site-specific mutational analyses of the conserved residues within WRDPLVDID indicated that Trp-637 plays a crucial role in Pah1 function. This work also demonstrated that the catalytic activity of Pah1 is required but is not sufficient for its in vivo functions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Expanding the Enzyme Universe: Accessing Non-Natural Reactions by Mechanism-Guided Directed Evolution

PubMed Central

Renata, Hans; Wang, Z. Jane

2015-01-01

High selectivities and exquisite control over reaction outcomes entice chemists to use biocatalysts in organic synthesis. However, many useful reactions are not accessible because they are not in nature’s known repertoire. We will use this review to outline an evolutionary approach to engineering enzymes to catalyze reactions not found in nature. We begin with examples of how nature has discovered new catalytic functions and how such evolutionary progressions have been recapitulated in the laboratory starting from extant enzymes. We then examine non-native enzyme activities that have been discovered and exploited for chemical synthesis, emphasizing reactions that do not have natural counterparts. The new functions have mechanistic parallels to the native reaction mechanisms that often manifest as catalytic promiscuity and the ability to convert from one function to the other with minimal mutation. We present examples of how non-natural activities have been improved by directed evolution, mimicking the process used by nature to create new catalysts. Examples of new enzyme functions include epoxide opening reactions with non-natural nucleophiles catalyzed by a laboratory-evolved halohydrin dehalogenase, cyclopropanation and other carbene transfer reactions catalyzed by cytochrome P450 variants, and non-natural modes of cyclization by a modified terpene synthase. Lastly, we describe discoveries of non-native catalytic functions that may provide future opportunities for expanding the enzyme universe. PMID:25649694

Proton Shuttles and Phosphatase Activity in Soluble Epoxide Hydrolase

PubMed Central

De Vivo, Marco; Ensing, Bernd; Peraro, Matteo Dal; Gomez, German A.; Christianson, David W.; Klein, Michael L.

2008-01-01

Recently, a novel metal (Mg2+)-dependent phosphatase activity has been discovered in the N-terminal domain of the soluble epoxide hydrolase (sEH), opening a new branch of fatty acid metabolism and providing an additional site for drug targeting. Importantly, the sEH N-terminal fold belongs to the haloacid dehalogenase (HAD) superfamily, which comprises a vast majority of phosphotransferases. Herein we present the results of a computational study of the sEH phosphatase activity, which includes classical molecular dynamics (MD) simulations and mixed quantum mechanical/molecular mechanics (QM/MM) calculations. Based on experimental results, a two-step mechanism has been proposed and herein investigated: 1) phosphoenzyme intermediate formation; 2) phosphoenzyme intermediate hydrolysis. Building on our earlier work, we now provide a detailed description of the reaction mechanism for the whole catalytic cycle along with its free energy profile. The present computations suggest metaphosphate-like transition states for these phosphoryl transfers. They also reveal that the enzyme promotes water deprotonation and facilitates shuttling of protons via a metal-ligand connecting water-bridge (WB). These WB mediated proton shuttles are crucial for the activation of the solvent nucleophile and for the stabilization of the leaving-group. Moreover, due to the conservation of structural features in the N-terminal catalytic site of sEH and other members of the HAD superfamily, we suggest a generalization of our findings to these other metal-dependent phosphatases. PMID:17212419

Assessment of In-Situ Reductive Dechlorination Using Compound-Specific Stable Isotopes, Functional-Gene Pcr, and Geochemical Data

PubMed Central

Carreón-Diazconti, Concepción; Santamaría, Johanna; Berkompas, Justin; Field, James A.; Brusseau, Mark L.

2010-01-01

Isotopic analysis and molecular-based bioassay methods were used in conjunction with geochemical data to assess intrinsic reductive dechlorination processes for a chlorinated-solvent contaminated site in Tucson, Arizona. Groundwater samples were obtained from monitoring wells within a contaminant plume comprising tetrachloroethene and its metabolites trichloroethene, cis-1,2-dichloroethene, vinyl chloride, and ethene, as well as compounds associated with free-phase diesel present at the site. Compound specific isotope (CSI) analysis was performed to characterize biotransformation processes influencing the transport and fate of the chlorinated contaminants. PCR analysis was used to assess the presence of indigenous reductive dechlorinators. The target regions employed were the 16s rRNA gene sequences of Dehalococcoides sp. and Desulfuromonas sp., and DNA sequences of genes pceA, tceA, bvcA, and vcrA, which encode reductive dehalogenases. The results of the analyses indicate that relevant microbial populations are present and that reductive dechlorination is presently occurring at the site. The results further show that potential degrader populations as well as biotransformation activity is non-uniformly distributed within the site. The results of laboratory microcosm studies conducted using groundwater collected from the field site confirmed the reductive dechlorination of tetrachloroethene to dichloroethene. This study illustrates the use of an integrated, multiple-method approach for assessing natural attenuation at a complex chlorinated-solvent contaminated site. PMID:19603638

Determinants of the microbial community structure of eutrophic, hyporheic river sediments polluted with chlorinated aliphatic hydrocarbons.

PubMed

Hamonts, Kelly; Ryngaert, Annemie; Smidt, Hauke; Springael, Dirk; Dejonghe, Winnie

2014-03-01

Chlorinated aliphatic hydrocarbons (CAHs) often discharge into rivers as contaminated groundwater baseflow. As biotransformation of CAHs in the impacted river sediments might be an effective remediation strategy, we investigated the determinants of the microbial community structure of eutrophic, CAH-polluted sediments of the Zenne River. Based on PCR-DGGE analysis, a high diversity of Bacteria, sulfate-reducing bacteria, Geobacteraceae, methanogenic archaea, and CAH-respiring Dehalococcoides was found. Depth in the riverbed, organic carbon content, CAH content and texture of the sediment, pore water temperature and conductivity, and concentrations of toluene and methane significantly contributed to the variance in the microbial community structure. On a meter scale, CAH concentrations alone explained only 6% of the variance in the Dehalococcoides and sulfate-reducing communities. On a cm-scale, however, CAHs explained 14.5-35% of the variation in DGGE profiles of Geobacteraceae, methanogens, sulfate-reducing bacteria, and Bacteria, while organic carbon content explained 2-14%. Neither the presence of the CAH reductive dehalogenase genes tceA, bvcA, and vcrA, nor the community structure of the targeted groups significantly differed between riverbed locations showing either no attenuation or reductive dechlorination, indicating that the microbial community composition was not a limiting factor for biotransformation in the Zenne sediments. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Diversity of Cobalamin Riboswitches in the Corrinoid-Producing Organohalide Respirer Desulfitobacterium hafniense

PubMed Central

Choudhary, Pallavi K.; Duret, Aurélie; Rohrbach-Brandt, Emmanuelle; Holliger, Christof; Sigel, Roland K. O.

2013-01-01

The strategic adaptation of prokaryotes in polluted niches involves the efficient regulation of their metabolism. The obligate anaerobe and metabolically versatile Desulfitobacterium hafniense reductively dechlorinates halogenated organic compounds (so-called organohalides). Some D. hafniense strains carry out organohalide respiration (OHR), a process which requires the use of corrinoid as a cofactor in reductive dehalogenases, the key enzymes in OHR. We report here the diversity of the cobalamin riboswitches that possibly regulate the corrinoid metabolism for D. hafniense. The analysis of available D. hafniense genomes indicates the presence of 18 cobalamin riboswitches located upstream of genes whose products are mainly involved in corrinoid biosynthesis and transport. To obtain insight into their function, the secondary structures of three of these RNA elements were predicted by Mfold, as well as analyzed by in-line probing. These RNA elements both display diversity in their structural elements and exhibit various affinities toward adenosylcobalamin that possibly relates to their role in the regulation of corrinoid metabolism. Furthermore, adenosylcobalamin-induced in vivo repression of RNA synthesis of the downstream located genes indicates that the corrinoid transporters and biosynthetic enzymes in D. hafniense strain TCE1 are regulated at the transcriptional level. Taken together, the riboswitch-mediated regulation of the complex corrinoid metabolism in D. hafniense could be of crucial significance in environments polluted with organohalides both to monitor their intracellular corrinoid level and to coexist with corrinoid-auxotroph OHR bacteria. PMID:24039263

Identifying and sequencing a Mycobacterium sp. strain F4 as a potential bioremediation agent for quinclorac.

PubMed

Li, Yingying; Chen, Wu; Wang, Yunsheng; Luo, Kun; Li, Yue; Bai, Lianyang; Luo, Feng

2017-01-01

Quinclorac is a widely used herbicide in rice filed. Unfortunately, quinclorac residues are phytotoxic to many crops/vegetables. The degradation of quinclorac in nature is very slow. On the other hand, degradation of quinclorac using bacteria can be an effective and efficient method to reduce its contamination. In this study, we isolated a quinclorac bioremediation bacterium strain F4 from quinclorac contaminated soils. Based on morphological characteristics and 16S rRNA gene sequence analysis, we identified strain F4 as Mycobacterium sp. We investigated the effects of temperature, pH, inoculation size and initial quinclorac concentration on growth and degrading efficiency of F4 and determined the optimal quinclorac degrading condition of F4. Under optimal degrading conditions, F4 degraded 97.38% of quinclorac from an initial concentration of 50 mg/L in seven days. Our indoor pot experiment demonstrated that the degradation products were non-phytotoxic to tobacco. After analyzing the quinclorac degradation products of F4, we proposed that F4 could employ two pathways to degrade quinclorac: one is through methylation, the other is through dechlorination. Furthermore, we reconstructed the whole genome of F4 through single molecular sequencing and de novo assembly. We identified 77 methyltransferases and eight dehalogenases in the F4 genome to support our hypothesized degradation path.

Identifying and sequencing a Mycobacterium sp. strain F4 as a potential bioremediation agent for quinclorac

PubMed Central

Li, Yingying; Chen, Wu; Wang, Yunsheng; Luo, Kun; Li, Yue; Bai, Lianyang

2017-01-01

Quinclorac is a widely used herbicide in rice filed. Unfortunately, quinclorac residues are phytotoxic to many crops/vegetables. The degradation of quinclorac in nature is very slow. On the other hand, degradation of quinclorac using bacteria can be an effective and efficient method to reduce its contamination. In this study, we isolated a quinclorac bioremediation bacterium strain F4 from quinclorac contaminated soils. Based on morphological characteristics and 16S rRNA gene sequence analysis, we identified strain F4 as Mycobacterium sp. We investigated the effects of temperature, pH, inoculation size and initial quinclorac concentration on growth and degrading efficiency of F4 and determined the optimal quinclorac degrading condition of F4. Under optimal degrading conditions, F4 degraded 97.38% of quinclorac from an initial concentration of 50 mg/L in seven days. Our indoor pot experiment demonstrated that the degradation products were non-phytotoxic to tobacco. After analyzing the quinclorac degradation products of F4, we proposed that F4 could employ two pathways to degrade quinclorac: one is through methylation, the other is through dechlorination. Furthermore, we reconstructed the whole genome of F4 through single molecular sequencing and de novo assembly. We identified 77 methyltransferases and eight dehalogenases in the F4 genome to support our hypothesized degradation path. PMID:28968436

Lindane degradation by Candida VITJzN04, a newly isolated yeast strain from contaminated soil: kinetic study, enzyme analysis and biodegradation pathway.

PubMed

Salam, Jaseetha Abdul; Das, Nilanjana

2014-04-01

A new yeast strain was isolated from sugarcane cultivation field which was able to utilize lindane as sole carbon source for growth in mineral medium. The yeast was identified and named as Candida sp. VITJzN04 based on a polyphasic approach using morphological, biochemical and 18S rDNA, D1/D2 and ITS sequence analysis. The isolated yeast strain efficiently degraded 600 mg L⁻¹ of lindane within 6 days in mineral medium under the optimal conditions (pH 7; temperature 30 °C and inoculum dosage 0.06 g L⁻¹) with the least half-life of 1.17 days and degradation constant of 0.588 per day. Lindane degradation was tested with various kinetic models and results revealed that the reaction could be described best by first-order and pseudo first-order models. In addition, involvement of the enzymes viz. dechlorinase, dehalogenase, dichlorohydroquinone reductive dechlorinase, lignin peroxidase and manganese peroxidase was noted during lindane degradation. Addition of H2O2 in the mineral medium showed 32 % enhancement of lindane degradation within 3 days. Based on the metabolites identified by GC-MS and FTIR analysis, sequential process of lindane degradation by Candida VITJzN04 was proposed. To the best of our knowledge, this is the first report of isolation and characterization of lindane-degrading Candida sp. and elucidation of enzyme systems during the degradation process.

Genome Sequence of the Mesophilic Thermotogales Bacterium Mesotoga prima MesG1.Ag.4.2 Reveals the Largest Thermotogales Genome To Date

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhaxybayeva, Olga; Swithers, Kristen S; Foght, Julia

2012-01-01

Here we describe the genome of Mesotoga prima MesG1.Ag4.2, the first genome of a mesophilic Thermotogales bacterium. Mesotoga prima was isolated from a polychlorinated biphenyl (PCB)-dechlorinating enrichment culture from Baltimore Harbor sediments. Its 2.97 Mb genome is considerably larger than any previously sequenced Thermotogales genomes, which range between 1.86 and 2.30 Mb. This larger size is due to both higher numbers of protein-coding genes and larger intergenic regions. In particular, the M. prima genome contains more genes for proteins involved in regulatory functions, for instance those involved in regulation of transcription. Together with its closest relative, Kosmotoga olearia, it alsomore » encodes different types of proteins involved in environmental and cell-cell interactions as compared with other Thermotogales bacteria. Amino acid composition analysis of M. prima proteins implies that this lineage has inhabited low-temperature environments for a long time. A large fraction of the M. prima genome has been acquired by lateral gene transfer (LGT): a DarkHorse analysis suggests that 766 (32%) of predicted protein-coding genes have been involved in LGT after Mesotoga diverged from the other Thermotogales lineages. A notable example of a lineage-specific LGT event is a reductive dehalogenase gene - a key enzyme in dehalorespiration, indicating M. prima may have a more active role in PCB dechlorination than was previously assumed.« less

Microbial reductive dehalogenation of trihalomethanes by a Dehalobacter-containing co-culture.

PubMed

Zhao, Siyan; Rogers, Matthew J; He, Jianzhong

2017-07-01

Trihalomethanes such as chloroform and bromoform, although well-known as a prominent class of disinfection by-products, are ubiquitously distributed in the environment due to widespread industrial usage in the past decades. Chloroform and bromoform are particularly concerning, of high concentrations detected and with long half-lives up to several hundred days in soils and groundwater. In this study, we report a Dehalobacter- and Desulfovibrio-containing co-culture that exhibits dehalogenation of chloroform (~0.61 mM) to dichloromethane and bromoform (~0.67 mM) to dibromomethane within 10-15 days. This co-culture was further found to dechlorinate 1,1,1-trichloroethane (1,1,1-TCA) (~0.65 mM) to 1,1-dichloroethane within 12 days. The Dehalobacter species present in this co-culture, designated Dehalobacter sp. THM1, was found to couple growth with dehalogenation of chloroform, bromoform, and 1,1,1-TCA. Strain THM1 harbors a newly identified reductive dehalogenase (RDase), ThmA, which catalyzes chloroform, bromoform, and 1,1,1-TCA dehalogenation. Additionally, based on the sequences of thmA and other identified chloroform RDase genes, ctrA, cfrA, and tmrA, a pair of chloroform RDase gene-specific primers were designed and successfully applied to investigate the chloroform dechlorinating potential of microbial communities. The comparative analysis of chloroform RDases with tetrachloroethene RDases suggests a possible approach in predicting the substrate specificity of uncharacterized RDases in the future.

Interaction Mode and Regioselectivity in Vitamin B12-Dependent Dehalogenation of Aryl Halides by Dehalococcoides mccartyi Strain CBDB1.

PubMed

Zhang, Shangwei; Adrian, Lorenz; Schüürmann, Gerrit

2018-02-20

The bacterium Dehalococcoides, strain CBDB1, transforms aromatic halides through reductive dehalogenation. So far, however, the structures of its vitamin B 12 -containing dehalogenases are unknown, hampering clarification of the catalytic mechanism and substrate specificity as basis for targeted remediation strategies. This study employs a quantum chemical donor-acceptor approach for the Co(I)-substrate electron transfer. Computational characterization of the substrate electron affinity at carbon-halogen bonds enables discriminating aromatic halides ready for dehalogenation by strain CBDB1 (active substrates) from nondehalogenated (inactive) counterparts with 92% accuracy, covering 86 of 93 bromobenzenes, chlorobenzenes, chlorophenols, chloroanilines, polychlorinated biphenyls, and dibenzo-p-dioxins. Moreover, experimental regioselectivity is predicted with 78% accuracy by a site-specific parameter encoding the overlap potential between the Co(I) HOMO (highest occupied molecular orbital) and the lowest-energy unoccupied sigma-symmetry substrate MO (σ*), and the observed dehalogenation pathways are rationalized with a success rate of 81%. Molecular orbital analysis reveals that the most reactive unoccupied sigma-symmetry orbital of carbon-attached halogen X (σ C-X * ) mediates its reductive cleavage. The discussion includes predictions for untested substrates, thus providing opportunities for targeted experimental investigations. Overall, the presently introduced orbital interaction model supports the view that with bacterial strain CBDB1, an inner-sphere electron transfer from the supernucleophile B 12 Co(I) to the halogen substituent of the aromatic halide is likely to represent the rate-determining step of the reductive dehalogenation.

Acetylene fuels TCE reductive dechlorination by defined Dehalococcoides/Pelobacter consortia

USGS Publications Warehouse

Mao, Xinwei; Oremland, Ronald S.; Liu, Tong; Landers, Abigail A; Baesman, Shaun; Alvarez-Cohen, Lisa

2017-01-01

Acetylene (C2H2) can be generated in contaminated groundwater sites as a consequence of chemical degradation of trichloroethene (TCE) by in situ minerals, and C2H2 is known to inhibit bacterial dechlorination. In this study, we show that while high C2H2 (1.3 mM) concentrations reversibly inhibit reductive dechlorination of TCE by Dehalococcoides mccartyi isolates as well as enrichment cultures containing D. mccartyi sp., low C2H2 (0.4 mM) concentrations do not inhibit growth or metabolism of D. mccartyi. Cocultures of Pelobacter SFB93, a C2H2-fermenting bacterium, with D. mccartyi strain 195 or with D. mccartyi strain BAV1 were actively sustained by providing acetylene as the electron donor and carbon source while TCE or cis-DCE served as the electron acceptor. Inhibition by acetylene of reductive dechlorination and methanogenesis in the enrichment culture ANAS was observed, and the inhibition was removed by adding Pelobacter SFB93 into the consortium. Transcriptomic analysis of D. mccartyi strain 195 showed genes encoding for reductive dehalogenases (e.g., tceA) were not affected during the C2H2-inhibition, while genes encoding for ATP synthase, biosynthesis, and Hym hydrogenase were down-regulated during C2H2 inhibition, consistent with the physiological observation of lower cell yields and reduced dechlorination rates in strain 195. These results will help facilitate the optimization of TCE-bioremediation at contaminated sites containing both TCE and C2H2.

Co-occurrence of genes for aerobic and anaerobic biodegradation of dichloroethane in organochlorine-contaminated groundwater.

PubMed

Munro, Jacob E; Kimyon, Önder; Rich, Deborah J; Koenig, Joanna; Tang, Sihui; Low, Adrian; Lee, Matthew; Manefield, Mike; Coleman, Nicholas V

2017-11-01

1,2-Dichloroethane (DCA) is a problematic groundwater pollutant. Factors influencing the distribution and activities of DCA-degrading bacteria are not well understood, which has hampered their application for bioremediation. Here, we used quantitative PCR to investigate the distribution of putative DCA-dehalogenating bacteria at a DCA-impacted site in Sydney (Australia). The dehalogenase genes dhlA, tceA and bvcA were detected in all groundwater samples (n = 15), while vcrA was found in 11/15 samples. The 16S rRNA gene sequences specific to the dehalogenating genera Dehalobacter, Desulfitobacterium and Dehalogenimonas were detected in 15/15, 13/15 and 13/15 samples, respectively, while Dehalococcoides sequences were found in 9/15 samples. The tceA, bvcA and vcrA genes occurred in the same samples as Dehalococcoides and Dehalobacter. Microcosm experiments confirmed the presence of bacteria capable of dechlorination under anoxic conditions. The abundance of the dhlA gene, which is found in hydrolytic DCA degraders, was positively correlated to the DCA concentration, and was unexpectedly most abundant in samples with low oxygen conditions. A dhlA-containing bacterium isolated from the site (Xanthobacter EL8) was capable of anaerobic growth on DCA under denitrifying conditions. The presence of diverse DCA-dehalogenating bacteria at this site indicates that natural attenuation or biostimulation could be valid approaches for site cleanup. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Acetylene Fuels TCE Reductive Dechlorination by Defined Dehalococcoides/Pelobacter Consortia.

PubMed

Mao, Xinwei; Oremland, Ronald S; Liu, Tong; Gushgari, Sara; Landers, Abigail A; Baesman, Shaun M; Alvarez-Cohen, Lisa

2017-02-21

Acetylene (C 2 H 2 ) can be generated in contaminated groundwater sites as a consequence of chemical degradation of trichloroethene (TCE) by in situ minerals, and C 2 H 2 is known to inhibit bacterial dechlorination. In this study, we show that while high C 2 H 2 (1.3 mM) concentrations reversibly inhibit reductive dechlorination of TCE by Dehalococcoides mccartyi isolates as well as enrichment cultures containing D. mccartyi sp., low C 2 H 2 (0.4 mM) concentrations do not inhibit growth or metabolism of D. mccartyi. Cocultures of Pelobacter SFB93, a C 2 H 2 -fermenting bacterium, with D. mccartyi strain 195 or with D. mccartyi strain BAV1 were actively sustained by providing acetylene as the electron donor and carbon source while TCE or cis-DCE served as the electron acceptor. Inhibition by acetylene of reductive dechlorination and methanogenesis in the enrichment culture ANAS was observed, and the inhibition was removed by adding Pelobacter SFB93 into the consortium. Transcriptomic analysis of D. mccartyi strain 195 showed genes encoding for reductive dehalogenases (e.g., tceA) were not affected during the C 2 H 2 -inhibition, while genes encoding for ATP synthase, biosynthesis, and Hym hydrogenase were down-regulated during C 2 H 2 inhibition, consistent with the physiological observation of lower cell yields and reduced dechlorination rates in strain 195. These results will help facilitate the optimization of TCE-bioremediation at contaminated sites containing both TCE and C 2 H 2 .

Studies on Mono- and Diiodohistidine. I. THE IDENTIFICATION OF IODOHISTIDINES FROM THYROIDAL IODOPROTEINS AND THEIR PERIPHERAL METABOLISM IN THE NORMAL MAN AND RAT

PubMed Central

Savoie, J. C.; Thomopoulos, P.; Savoie, F.

1973-01-01

The problem as to whether iodohistidines are normally biosynthetized in thyroglobulin and thyralbumin has been examined both in man and the rat. Evidence has been obtained for the first time that diiodohistidine (DIH) is present in both species in these two iodoproteins. The biosynthesis of monoiodohistidine (MIH) in the thyroglobulin of the normal rat has been confirmed and extended to rat thyralbumin and to human thyroid iodoproteins. The iodohistidine identification is based on five original methods including: (a) the preparation of stable and radioiodine-labeled iodohistidines; (b) the protection of the labile iodohistidines during the iodoprotein enzymatic hydrolysis; (c) the isolation of iodohistidines by ion-exchange resin chromatography; (d) their separation from each other and from iodinated cationic butanol-insoluble compounds by Sephadex G-10 chromatography; and (e) their purification by successive crystallizations to a constant specific activity. Iodohistidine levels (in percent of protein radioactivity from iodide given in vivo) were found comparable in man and the rat. However, the values (mean ±SE) for thyroglobulin (MIH, 0.61±0.10%; DIH, 0.050±0.015%) and for thyralbumin (MIH, 2.61±0.57%; DIH, 0.28±0.09%) differ significantly (P < 0.05). Iodohistidines are stable during in vitro exposure to iodotyrosine dehalogenase preparations. In contrast to iodotyrosines the iodohistidines when given in vivo to man either orally or intravenously were in large part recovered in 24-h urines. PMID:4682378

Differential protein accumulations in isolates of the strawberry wilt pathogen Fusarium oxysporum f. sp. fragariae differing in virulence.

PubMed

Fang, Xiangling; Barbetti, Martin J

2014-08-28

This study was conducted to define differences in Fusarium oxysporum f. sp. fragariae (Fof) isolates with different virulence efficiency to strawberry at the proteome level, in combination with their differences in mycelial growth, conidial production and germination. Comparative proteome analyses revealed substantial differences in mycelial proteomes between Fof isolates, where the 54 differentially accumulated protein spots were consistently over-accumulated or exclusively in the highly virulent isolate. These protein spots were identified through MALDI-TOF/TOF mass spectrometry analyses, and the identified proteins were mainly related to primary and protein metabolism, antioxidation, electron transport, cell cycle and transcription based on their putative functions. Proteins of great potential as Fof virulence factors were those involved in ubiquitin/proteasome-mediated protein degradation and reactive oxygen species detoxification; the hydrolysis-related protein haloacid dehalogenase superfamily hydrolase; 3,4-dihydroxy-2-butanone 4-phosphate synthase associated with riboflavin biosynthesis; and those exclusive to the highly virulent isolate. In addition, post-translational modifications may also make an important contribution to Fof virulence. F. oxysporum f. sp. fragariae (Fof), the causal agent of Fusarium wilt in strawberry, is a serious threat to commercial strawberry production worldwide. However, factors and mechanisms contributing to Fof virulence remained unknown. This study provides knowledge of the molecular basis for the differential expression of virulence in Fof, allowing new possibilities towards developing alternative and more effective strategies to manage Fusarium wilt. Copyright © 2014 Elsevier B.V. All rights reserved.

Dehalococcoides abundance and alternate electron acceptor effects on large, flow-through trichloroethene dechlorinating columns.

PubMed

Mirza, Babur S; Sorensen, Darwin L; Dupont, R Ryan; McLean, Joan E

2016-03-01

Trichloroethene (TCE) in groundwater is a major health concern and biostimulation/bioaugmentation-based strategies have been evaluated to achieve complete reductive dechlorination with varying success. Different carbon sources were hypothesized to stimulate different extents of TCE reductive dechlorination. Ecological conditions that developed different dechlorination stages were investigated by quantitating Dehalococcoides 16S rRNA (Dhc) and reductive dehalogenase gene abundance, and by describing biogeochemical properties of laboratory columns in response to this biostimulation. Eight large columns (183 cm × 15.2 cm), packed with aquifer material from Hill AFB, Utah, that were continuously fed TCE for 7.5 years. Duplicate columns were biostimulated with whey or one of two different Newman Zone® emulsified oil formulations containing either nonionic surfactant (EOLN) or standard surfactant (EOL). Two columns were non-stimulated controls. Complete (whey amended), partial (EOLN amended), limited (EOL), and non-TCE dehalogenating systems (controls) developed over the course of the study. Bioaugmentation of half of the columns with Bachman Road culture 3 years prior to dismantling did not influence the extent of TCE dehalogenation. Multivariate analysis clustered samples by biostimulation treatments and extent of TCE dehalogenation. Dhc, tceA, and bvcA gene concentrations did not show a consistent relationship with TCE dehalogenation but the vcrA gene was more abundant in completely dehalogenating, whey-treated columns. The whey columns developed strongly reducing conditions producing Fe(II), sulfide, and methane. Biostimulation with different carbon and energy sources can support high concentrations of diverse Dhc, but carbon addition has a major influence on biogeochemical processes effecting the extent of TCE dehalogenation.

Bacterial diversity and real-time PCR based assessment of linA and linB gene distribution at hexachlorocyclohexane contaminated sites.

PubMed

Lal, Devi; Jindal, Swati; Kumari, Hansi; Jit, Simran; Nigam, Aeshna; Sharma, Pooja; Kumari, Kirti; Lal, Rup

2015-03-01

The disposal of hexachlorocyclohexane (HCH) muck has created large number of HCH dumpsites all over the world from where the harmful HCH isomers are leaking into the environment. Bacteria have evolved at such contaminated sites that have the ability to degrade HCH. Degradation of various HCH isomers in bacterial strains is mediated primarily by two genes: linA and linB which encode dehydrochlorinase and haloalkane dehalogenase respectively. In this study we explored one such highly contaminated HCH dumpsite located in Lucknow, Uttar Pradesh, India. To assess the biostimulation potential of the contaminated site, microbial diversity study and real-time PCR based quantification of lin genes was carried out. The soil samples from dumpsite and surrounding areas were found to be highly contaminated with HCH residue levels as high as 1.8 × 10(5)  mg kg(-1). The residues were detected in areas upto 13 km from the dumpsite. Sphingomonads, Chromohalobacter, and Marinobacter were the dominant genera present at the dump-site. Role of Sphingomonads in HCH degradation has been well documented. The highest copy numbers of linA and linB genes as determined using real-time PCR were 6.2 × 10(4) and 5.3 × 10(5), respectively, were found in sample from the dump site. The presence of Sphingomonads, linA, and linB genes from HCH contaminated soil indicates the presence of indigenous bacterial communities capable of HCH degradation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combined C and Cl isotope effects indicate differences between corrinoids and enzyme (Sulfurospirillum multivorans PceA) in reductive dehalogenation of tetrachloroethene, but not trichloroethene.

PubMed

Renpenning, Julian; Keller, Sebastian; Cretnik, Stefan; Shouakar-Stash, Orfan; Elsner, Martin; Schubert, Torsten; Nijenhuis, Ivonne

2014-10-21

The role of the corrinoid cofactor in reductive dehalogenation catalysis by tetrachloroethene reductive dehalogenase (PceA) of Sulfurospirillum multivorans was investigated using isotope analysis of carbon and chlorine. Crude extracts containing PceA--harboring either a native norpseudo-B12 or the alternative nor-B12 cofactor--were applied for dehalogenation of tetrachloroethene (PCE) or trichloroethene (TCE), and compared to abiotic dehalogenation with the respective purified corrinoids (norpseudovitamin B12 and norvitamin B12), as well as several commercially available cobalamins and cobinamide. Dehalogenation of TCE resulted in a similar extent of C and Cl isotope fractionation, and in similar dual-element isotope slopes (εC/εCl) of 5.0-5.3 for PceA enzyme and 3.7-4.5 for the corrinoids. Both observations support an identical reaction mechanism. For PCE, in contrast, observed C and Cl isotope fractionation was smaller in enzymatic dehalogenation, and dual-element isotope slopes (2.2-2.8) were distinctly different compared to dehalogenation mediated by corrinoids (4.6-7.0). Remarkably, εC/εCl of PCE depended in addition on the corrinoid type: εC/εCl values of 4.6 and 5.0 for vitamin B12 and norvitamin B12 were significantly different compared to values of 6.9 and 7.0 for norpseudovitamin B12 and dicyanocobinamide. Our results therefore suggest mechanistic and/or kinetic differences in catalytic PCE dehalogenation by enzymes and different corrinoids, whereas such differences were not observed for TCE.

CAVER 3.0: A Tool for the Analysis of Transport Pathways in Dynamic Protein Structures

PubMed Central

Strnad, Ondrej; Brezovsky, Jan; Kozlikova, Barbora; Gora, Artur; Sustr, Vilem; Klvana, Martin; Medek, Petr; Biedermannova, Lada; Sochor, Jiri; Damborsky, Jiri

2012-01-01

Tunnels and channels facilitate the transport of small molecules, ions and water solvent in a large variety of proteins. Characteristics of individual transport pathways, including their geometry, physico-chemical properties and dynamics are instrumental for understanding of structure-function relationships of these proteins, for the design of new inhibitors and construction of improved biocatalysts. CAVER is a software tool widely used for the identification and characterization of transport pathways in static macromolecular structures. Herein we present a new version of CAVER enabling automatic analysis of tunnels and channels in large ensembles of protein conformations. CAVER 3.0 implements new algorithms for the calculation and clustering of pathways. A trajectory from a molecular dynamics simulation serves as the typical input, while detailed characteristics and summary statistics of the time evolution of individual pathways are provided in the outputs. To illustrate the capabilities of CAVER 3.0, the tool was applied for the analysis of molecular dynamics simulation of the microbial enzyme haloalkane dehalogenase DhaA. CAVER 3.0 safely identified and reliably estimated the importance of all previously published DhaA tunnels, including the tunnels closed in DhaA crystal structures. Obtained results clearly demonstrate that analysis of molecular dynamics simulation is essential for the estimation of pathway characteristics and elucidation of the structural basis of the tunnel gating. CAVER 3.0 paves the way for the study of important biochemical phenomena in the area of molecular transport, molecular recognition and enzymatic catalysis. The software is freely available as a multiplatform command-line application at http://www.caver.cz. PMID:23093919

CAVER 3.0: a tool for the analysis of transport pathways in dynamic protein structures.

PubMed

Chovancova, Eva; Pavelka, Antonin; Benes, Petr; Strnad, Ondrej; Brezovsky, Jan; Kozlikova, Barbora; Gora, Artur; Sustr, Vilem; Klvana, Martin; Medek, Petr; Biedermannova, Lada; Sochor, Jiri; Damborsky, Jiri

2012-01-01

Tunnels and channels facilitate the transport of small molecules, ions and water solvent in a large variety of proteins. Characteristics of individual transport pathways, including their geometry, physico-chemical properties and dynamics are instrumental for understanding of structure-function relationships of these proteins, for the design of new inhibitors and construction of improved biocatalysts. CAVER is a software tool widely used for the identification and characterization of transport pathways in static macromolecular structures. Herein we present a new version of CAVER enabling automatic analysis of tunnels and channels in large ensembles of protein conformations. CAVER 3.0 implements new algorithms for the calculation and clustering of pathways. A trajectory from a molecular dynamics simulation serves as the typical input, while detailed characteristics and summary statistics of the time evolution of individual pathways are provided in the outputs. To illustrate the capabilities of CAVER 3.0, the tool was applied for the analysis of molecular dynamics simulation of the microbial enzyme haloalkane dehalogenase DhaA. CAVER 3.0 safely identified and reliably estimated the importance of all previously published DhaA tunnels, including the tunnels closed in DhaA crystal structures. Obtained results clearly demonstrate that analysis of molecular dynamics simulation is essential for the estimation of pathway characteristics and elucidation of the structural basis of the tunnel gating. CAVER 3.0 paves the way for the study of important biochemical phenomena in the area of molecular transport, molecular recognition and enzymatic catalysis. The software is freely available as a multiplatform command-line application at http://www.caver.cz.

A global view of structure–function relationships in the tautomerase superfamily

PubMed Central

Davidson, Rebecca; Baas, Bert-Jan; Akiva, Eyal; Holliday, Gemma L.; Polacco, Benjamin J.; LeVieux, Jake A.; Pullara, Collin R.; Zhang, Yan Jessie; Whitman, Christian P.

2018-01-01

The tautomerase superfamily (TSF) consists of more than 11,000 nonredundant sequences present throughout the biosphere. Characterized members have attracted much attention because of the unusual and key catalytic role of an N-terminal proline. These few characterized members catalyze a diverse range of chemical reactions, but the full scale of their chemical capabilities and biological functions remains unknown. To gain new insight into TSF structure–function relationships, we performed a global analysis of similarities across the entire superfamily and computed a sequence similarity network to guide classification into distinct subgroups. Our results indicate that TSF members are found in all domains of life, with most being present in bacteria. The eukaryotic members of the cis-3-chloroacrylic acid dehalogenase subgroup are limited to fungal species, whereas the macrophage migration inhibitory factor subgroup has wide eukaryotic representation (including mammals). Unexpectedly, we found that 346 TSF sequences lack Pro-1, of which 85% are present in the malonate semialdehyde decarboxylase subgroup. The computed network also enabled the identification of similarity paths, namely sequences that link functionally diverse subgroups and exhibit transitional structural features that may help explain reaction divergence. A structure-guided comparison of these linker proteins identified conserved transitions between them, and kinetic analysis paralleled these observations. Phylogenetic reconstruction of the linker set was consistent with these findings. Our results also suggest that contemporary TSF members may have evolved from a short 4-oxalocrotonate tautomerase–like ancestor followed by gene duplication and fusion. Our new linker-guided strategy can be used to enrich the discovery of sequence/structure/function transitions in other enzyme superfamilies. PMID:29184004

Haloacetic acid-degrading bacterial communities in drinking water systems as determined by cultivation and by terminal restriction fragment length polymorphism of PCR-amplified haloacid dehalogenase gene fragments.

PubMed

Grigorescu, A S; Hozalski, R M; Lapara, T M

2012-04-01

To characterize the HAA-degrading bacteria in drinking water systems. Haloacetic acid (HAA)-degrading bacteria were analysed in drinking water systems by cultivation and by a novel application of terminal restriction fragment length polymorphism (tRFLP). Substantial similarities were observed among the tRFLP patterns of dehI and dehII gene fragments in drinking water samples obtained from three different cities (Minneapolis, MN; St Paul, MN; Bucharest, Romania) and from one biologically active granular activated carbon filter (Hershey, PA). The dominant fragment in the tRFLP profiles of dehI genes from the drinking water samples matched the pattern from an Afipia sp. that was previously isolated from drinking water. In contrast, the dominant fragment in the tRFLP profiles of dehII genes did not match any previously characterized dehII gene fragment. PCR cloning was used to characterize this gene fragment, which had <65% nucleotide sequence identity with any previously characterized dehII gene. Afipia spp. are an appropriate model organism for studying the biodegradation of HAAs in drinking water distribution systems as encoded by dehI genes; the organism that harbours the most prominent dehII gene in drinking water has yet to be cultivated and identified. The development of a novel application of tRFLP targeting dehI and dehII genes could be broadly useful in understanding HAA-degrading bacteria in numerous environments. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Algorithms and semantic infrastructure for mutation impact extraction and grounding.

PubMed

Laurila, Jonas B; Naderi, Nona; Witte, René; Riazanov, Alexandre; Kouznetsov, Alexandre; Baker, Christopher J O

2010-12-02

Mutation impact extraction is a hitherto unaccomplished task in state of the art mutation extraction systems. Protein mutations and their impacts on protein properties are hidden in scientific literature, making them poorly accessible for protein engineers and inaccessible for phenotype-prediction systems that currently depend on manually curated genomic variation databases. We present the first rule-based approach for the extraction of mutation impacts on protein properties, categorizing their directionality as positive, negative or neutral. Furthermore protein and mutation mentions are grounded to their respective UniProtKB IDs and selected protein properties, namely protein functions to concepts found in the Gene Ontology. The extracted entities are populated to an OWL-DL Mutation Impact ontology facilitating complex querying for mutation impacts using SPARQL. We illustrate retrieval of proteins and mutant sequences for a given direction of impact on specific protein properties. Moreover we provide programmatic access to the data through semantic web services using the SADI (Semantic Automated Discovery and Integration) framework. We address the problem of access to legacy mutation data in unstructured form through the creation of novel mutation impact extraction methods which are evaluated on a corpus of full-text articles on haloalkane dehalogenases, tagged by domain experts. Our approaches show state of the art levels of precision and recall for Mutation Grounding and respectable level of precision but lower recall for the task of Mutant-Impact relation extraction. The system is deployed using text mining and semantic web technologies with the goal of publishing to a broad spectrum of consumers.

Functional metagenomics of oil-impacted mangrove sediments reveals high abundance of hydrolases of biotechnological interest.

PubMed

Ottoni, Júlia Ronzella; Cabral, Lucélia; de Sousa, Sanderson Tarciso Pereira; Júnior, Gileno Vieira Lacerda; Domingos, Daniela Ferreira; Soares Junior, Fábio Lino; da Silva, Mylenne Calciolari Pinheiro; Marcon, Joelma; Dias, Armando Cavalcante Franco; de Melo, Itamar Soares; de Souza, Anete Pereira; Andreote, Fernando Dini; de Oliveira, Valéria Maia

2017-07-01

Mangroves are located in coastal wetlands and are susceptible to the consequences of oil spills, what may threaten the diversity of microorganisms responsible for the nutrient cycling and the consequent ecosystem functioning. Previous reports show that high concentration of oil favors the incidence of epoxide hydrolases and haloalkane dehalogenases in mangroves. This finding has guided the goals of this study in an attempt to broaden the analysis to other hydrolases and thereby verify whether oil contamination interferes with the prevalence of particular hydrolases and their assigned microorganisms. For this, an in-depth survey of the taxonomic and functional microbial diversity recovered in a fosmid library (Library_Oil Mgv) constructed from oil-impacted Brazilian mangrove sediment was carried out. Fosmid DNA of the whole library was extracted and submitted to Illumina HiSeq sequencing. The resulting Library Oil_Mgv dataset was further compared with those obtained by direct sequencing of environmental DNA from Brazilian mangroves (from distinct regions and affected by distinct sources of contamination), focusing on hydrolases with potential use in biotechnological processes. The most abundant hydrolases found were proteases, esterases and amylases, with similar occurrence profile in all datasets. The main microbial groups harboring such hydrolase-encoding genes were distinct in each mangrove, and in the fosmid library these enzymes were mainly assigned to Chloroflexaceae (for amylases), Planctomycetaceae (for esterases) and Bradyrhizobiaceae (for proteases). Assembly and analysis of Library_Oil Mgv reads revealed three potentially novel enzymes, one epoxide hydrolase, one xylanase and one amylase, to be further investigated via heterologous expression assays.

DC-Analyzer-facilitated combinatorial strategy for rapid directed evolution of functional enzymes with multiple mutagenesis sites.

PubMed

Wang, Xiong; Zheng, Kai; Zheng, Huayu; Nie, Hongli; Yang, Zujun; Tang, Lixia

2014-12-20

Iterative saturation mutagenesis (ISM) has been shown to be a powerful method for directed evolution. In this study, the approach was modified (termed M-ISM) by combining the single-site saturation mutagenesis method with a DC-Analyzer-facilitated combinatorial strategy, aiming to evolve novel biocatalysts efficiently in the case where multiple sites are targeted simultaneously. Initially, all target sites were explored individually by constructing single-site saturation mutagenesis libraries. Next, the top two to four variants in each library were selected and combined using the DC-Analyzer-facilitated combinatorial strategy. In addition to site-saturation mutagenesis, iterative saturation mutagenesis also needed to be performed. The advantages of M-ISM over ISM were that the screening effort is greatly reduced, and the entire M-ISM procedure was less time-consuming. The M-ISM strategy was successfully applied to the randomization of halohydrin dehalogenase from Agrobacterium radiobacter AD1 (HheC) when five interesting sites were targeted simultaneously. After screening 900 clones in total, six positive mutants were obtained. These mutants exhibited 4.0- to 9.3-fold higher k(cat) values than did the wild-type HheC toward 1,3-dichloro-2-propanol. However, with the ISM strategy, the best hit showed a 5.9-fold higher k(cat) value toward 1,3-DCP than the wild-type HheC, which was obtained after screening 4000 clones from four rounds of mutagenesis. Therefore, M-ISM could serve as a simple and efficient version of ISM for the randomization of target genes with multiple positions of interest.

Yarrowia lipolytica NCIM 3589, a tropical marine yeast, degrades bromoalkanes by an initial hydrolytic dehalogenation step.

PubMed

Vatsal, Aakanksha; Zinjarde, Smita S; Kumar, Ameeta Ravi

2015-04-01

The widespread industrial use of organobromines which are known persistent organic pollutants has led to their accumulation in sediments and water bodies causing harm to animals and humans. While degradation of organochlorines by bacteria is well documented, information regarding degradation pathways of these recalcitrant organobromines is scarce. Hence, their fates and effects on the environment are of concern. The present study shows that a tropical marine yeast, Yarrowia lipolytica NCIM 3589 aerobically degrades bromoalkanes differing in carbon chain length and position of halogen substitution viz., 2-bromopropane (2-BP), 1-bromobutane (1-BB), 1,5 dibromopentane (1,5-DBP) and 1-bromodecane (1-BD) as seen by an increase in cell mass, release of bromide and concomitant decrease in concentration of brominated compound. The amount of bromoalkane degraded was 27.3, 21.9, 18.0 and 38.3 % with degradation rates of 0.076, 0.058, 0.046 and 0.117/day for 2-BP, 1-BB, 1,5-DBP and 1-BD, respectively. The initial product formed respectively were alcohols viz., 2-propanol, 1-butanol, 1-bromo, 5-pentanol and 1-decanol as detected by GC-MS. These were further metabolized to fatty acids viz., 2-propionic, 1-butyric and 1-decanoic acid eventually leading to carbon dioxide formation. Neither higher chain nor brominated fatty acids were detected. An inducible extracellular dehalogenase responsible for removal of bromide was detected with activities of 21.07, 18.82, 18.96 and 26.67 U/ml for 2-BP, 1-BB, 1,5-DBP and 1-BD, respectively. We report here for the first time the proposed aerobic pathway of bromoalkane degradation by an eukaryotic microbe Y. lipolytica 3589, involving an initial hydrolytic dehalogenation step.

Site-Specific Mobilization of Vinyl Chloride Respiration Islands by a Mechanism Common in Dehalococcoides

PubMed Central

2011-01-01

Background Vinyl chloride is a widespread groundwater pollutant and Group 1 carcinogen. A previous comparative genomic analysis revealed that the vinyl chloride reductase operon, vcrABC, of Dehalococcoides sp. strain VS is embedded in a horizontally-acquired genomic island that integrated at the single-copy tmRNA gene, ssrA. Results We targeted conserved positions in available genomic islands to amplify and sequence four additional vcrABC -containing genomic islands from previously-unsequenced vinyl chloride respiring Dehalococcoides enrichments. We identified a total of 31 ssrA-specific genomic islands from Dehalococcoides genomic data, accounting for 47 reductive dehalogenase homologous genes and many other non-core genes. Sixteen of these genomic islands contain a syntenic module of integration-associated genes located adjacent to the predicted site of integration, and among these islands, eight contain vcrABC as genetic 'cargo'. These eight vcrABC -containing genomic islands are syntenic across their ~12 kbp length, but have two phylogenetically discordant segments that unambiguously differentiate the integration module from the vcrABC cargo. Using available Dehalococcoides phylogenomic data we estimate that these ssrA-specific genomic islands are at least as old as the Dehalococcoides group itself, which in turn is much older than human civilization. Conclusions The vcrABC -containing genomic islands are a recently-acquired subset of a diverse collection of ssrA-specific mobile elements that are a major contributor to strain-level diversity in Dehalococcoides, and may have been throughout its evolution. The high similarity between vcrABC sequences is quantitatively consistent with recent horizontal acquisition driven by ~100 years of industrial pollution with chlorinated ethenes. PMID:21635780

Two candidate genes for two quantitative trait loci epistatically attenuate hypertension in a novel pathway.

PubMed

Chauvet, Cristina; Ménard, Annie; Deng, Alan Y

2015-09-01

Multiple quantitative trait loci (QTLs) for blood pressure (BP) have been detected in rat models of human polygenic hypertension. They influence BP physiologically via epistatic modules. Little is known about the causal genes and virtually nothing is known on modularized mechanisms governing their regulatory connections. Two genes responsible for two individual BP QTLs on rat Chromosome 18 have been identified that belong to the same epistatic module. Treacher Collins-Franceschetti syndrome 1 (Tcof1) gene is the only function candidate for C18QTL3. Haloacid dehalogenase like hydrolase domain containing 2 (Hdhd2), although a gene of previously unknown function, is C18QTL4, and encodes a newly identified phosphatase. The current work has provided the premier evidence that Hdhd2/C18QTL4 and Tcof1/C18QTL3 may be involved in polygenic hypertension. Hdhd2/C18QTL4 can regulate the function of Tcof1/C18QTL3 via de-phosphorylation, and, for the first time, furbishes a molecular mechanism in support of a genetically epistatic hierarchy between two BP QTLs, and thus authenticates the epistasis-common pathway paradigm. The pathway initiated by Hdhd2/C18QTL4 upstream of Tcof1/C18QTL3 reveals novel mechanistic insights into BP modulations. Their discovery might yield innovative therapeutic targets and diagnostic tools predicated on a novel BP cause and mechanism that is determined by a regulatory hierarchy. Optimizing the de-phosphorylation capability and its downstream target could be antihypertensive. The conceptual paradigm of an order and regulatory hierarchy may help unravel genetic and molecular relationships among certain human BP QTLs.

Absolute quantification of Dehalococcoides proteins: enzyme bioindicators of chlorinated ethene dehalorespiration.

PubMed

Werner, Jeffrey J; Ptak, A Celeste; Rahm, Brian G; Zhang, Sheng; Richardson, Ruth E

2009-10-01

The quantification of trace proteins in complex environmental samples and mixed microbial communities would be a valuable monitoring tool in countless applications, including the bioremediation of groundwater contaminated with chlorinated solvents. Measuring the concentrations of specific proteins provides unique information about the activity and physiological state of organisms in a sample. We developed sensitive (< 5 fmol), selective bioindicator assays for the absolute quantification of select proteins used by Dehalococcoides spp. when reducing carbon atoms in the common pollutants trichloroethene (TCE) and tetrachloroethene (PCE). From complex whole-sample digests of two different dechlorinating mixed communities, we monitored the chromatographic peaks of selected tryptic peptides chosen to represent 19 specific Dehalococcoides proteins. This was accomplished using multiple-reaction monitoring (MRM) assays using nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS), which provided the selectivity, sensitivity and reproducibility required to quantify Dehalococcoides proteins in complex samples. We observed reproducible peak areas (average CV = 0.14 over 4 days, n = 3) and linear responses in standard curves (n = 5, R(2) > 0.98) using synthetic peptide standards spiked into a background matrix of sediment peptides. We detected and quantified TCE reductive dehalogenase (TceA) at 7.6 +/- 1.7 x 10(3) proteins cell(-1) in the KB1 bioaugmentation culture, previously thought to be lacking TceA. Fragmentation data from MS/MS shotgun proteomics experiments were helpful in developing the MRM targets. Similar shotgun proteomics data are emerging in labs around the world for many environmentally relevant microbial proteins, and these data are a valuable resource for the future development of MRM assays. We expect targeted peptide quantification in environmental samples to be a useful tool in environmental monitoring.

Sustainable growth of Dehalococcoides mccartyi 195 by corrinoid salvaging and remodeling in defined lactate-fermenting consortia.

PubMed

Men, Yujie; Seth, Erica C; Yi, Shan; Allen, Robert H; Taga, Michiko E; Alvarez-Cohen, Lisa

2014-04-01

Corrinoids are essential cofactors of reductive dehalogenases in Dehalococcoides mccartyi, an important bacterium in bioremediation, yet sequenced D. mccartyi strains do not possess the complete pathway for de novo corrinoid biosynthesis. Pelosinus sp. and Desulfovibrio sp. have been detected in dechlorinating communities enriched from contaminated groundwater without exogenous cobalamin corrinoid. To investigate the corrinoid-related interactions among key members of these communities, we constructed consortia by growing D. mccartyi strain 195 (Dhc195) in cobalamin-free, trichloroethene (TCE)- and lactate-amended medium in cocultures with Desulfovibrio vulgaris Hildenborough (DvH) or Pelosinus fermentans R7 (PfR7) and with both in tricultures. Only the triculture exhibited sustainable dechlorination and cell growth when a physiological level of 5,6-dimethylbenzimidazole (DMB), the lower ligand of cobalamin, was provided. In the triculture, DvH provided hydrogen while PfR7 provided corrinoids to Dhc195, and the initiation of dechlorination and Dhc195 cell growth was highly dependent on the growth of PfR7. Corrinoid analysis indicated that Dhc195 imported and remodeled the phenolic corrinoids produced by PfR7 into cobalamin in the presence of DMB. Transcriptomic analyses of Dhc195 showed the induction of the CbiZ-dependent corrinoid-remodeling pathway and BtuFCD corrinoid ABC transporter genes during corrinoid salvaging and remodeling. In contrast, another operon annotated to encode a putative iron/cobalamin ABC transporter (DET1174-DET1176) was induced when cobalamin was exogenously provided. Interestingly, a global upregulation of phage-related genes was observed when PfR7 was present. These findings provide insights into both the gene regulation of corrinoid salvaging and remodeling in Dhc195 when it is grown without exogenous cobalamin and microbe-to-microbe interactions in dechlorinating microbial communities.

Reductive Dehalogenation of Brominated Phenolic Compounds by Microorganisms Associated with the Marine Sponge Aplysina aerophoba

PubMed Central

Ahn, Young-Beom; Rhee, Sung-Keun; Fennell, Donna E.; Kerkhof, Lee J.; Hentschel, Ute; Häggblom, Max M.

2003-01-01

Marine sponges are natural sources of brominated organic compounds, including bromoindoles, bromophenols, and bromopyrroles, that may comprise up to 12% of the sponge dry weight. Aplysina aerophoba sponges harbor large numbers of bacteria that can amount to 40% of the biomass of the animal. We postulated that there might be mechanisms for microbially mediated degradation of these halogenated chemicals within the sponges. The capability of anaerobic microorganisms associated with the marine sponge to transform haloaromatic compounds was tested under different electron-accepting conditions (i.e., denitrifying, sulfidogenic, and methanogenic). We observed dehalogenation activity of sponge-associated microorganisms with various haloaromatics. 2-Bromo-, 3-bromo-, 4-bromo-, 2,6-dibromo-, and 2,4,6-tribromophenol, and 3,5-dibromo-4-hydroxybenzoate were reductively debrominated under methanogenic and sulfidogenic conditions with no activity observed in the presence of nitrate. Monochlorinated phenols were not transformed over a period of 1 year. Debromination of 2,4,6-tribromophenol, and 2,6-dibromophenol to 2-bromophenol was more rapid than the debromination of the monobrominated phenols. Ampicillin and chloramphenicol inhibited activity, suggesting that dehalogenation was mediated by bacteria. Characterization of the debrominating methanogenic consortia by using terminal restriction fragment length polymorphism (TRFLP) and denaturing gradient gel electrophoresis analysis indicated that different 16S ribosomal DNA (rDNA) phylotypes were enriched on the different halogenated substrates. Sponge-associated microorganisms enriched on organobromine compounds had distinct 16S rDNA TRFLP patterns and were most closely related to the δ subgroup of the proteobacteria. The presence of homologous reductive dehalogenase gene motifs in the sponge-associated microorganisms suggested that reductive dehalogenation might be coupled to dehalorespiration. PMID:12839794

Ecology and distribution of a new biomarker linked to 1,2-dichloropropane dechlorination in subsurface environments

NASA Astrophysics Data System (ADS)

Padilla-Crespo, E.; Loeffler, F. E.

2011-12-01

Reductive dechlorination plays a major role in the transformation and detoxification of chlorinated solvents, including chlorinated ethenes. Molecular biological tools are being applied at contaminated sites in order to assess the process-specific biomarkers that impact site performance, and to monitor the progress of bioremediation approaches. The few current biomarker genes in use provide an incomplete picture of the reductively dechlorinating bacterial community; this is a limitation for implementing enhanced bioremediation and monitored natural attenuation as cleanup strategies at chlorinated solvent contaminated sites. Reductively dehalogenating organisms, particularly Dehalococcoides (Dhc) strains, possess multiple reductive dehalogenase (RDase) genes, which are promising targets to specifically monitor dehalogenation processes of interest. Dehalococcoides populations in two highly enriched cultures (RC and KS) have been implicated in the reductive dechlorination of dechlorination of 1,2-dichloropropane (1,2-D), a widespread halogenated organic pollutant, to the non-toxic propene. Using a combined approach of transcription, expression and molecular analysis a new biomarker linked to 1,2-dichloropropane has been identified in Dhc strains RC and KS providing for the first time, convincing evidence of a specific RDase implicated in 1,2-D dechlorination to propene. Further analyses imply that new biomarker is in a "mobile DNA segment", a genomic island (GI) of horizontal gene transfer origin. A valid quantitative PCR approach was designed to detect and enumerate this gene in cultures and environmental samples; this will be a useful to bioremediation practitioners to more efficiently implement reductive dechlorination as a remediation tool. The new biomarker has been identified in fresh water sediment samples from different geographical locations in Europe, North and South America. Further research aims to shed light on RDase gene dissemination and the adaptation of dehalospiring populations in subsurface environments.

Structure of Human B12 Trafficking Protein CblD Reveals Molecular Mimicry and Identifies a New Subfamily of Nitro-FMN Reductases.

PubMed

Yamada, Kazuhiro; Gherasim, Carmen; Banerjee, Ruma; Koutmos, Markos

2015-12-04

In mammals, B12 (or cobalamin) is an essential cofactor required by methionine synthase and methylmalonyl-CoA mutase. A complex intracellular pathway supports the assimilation of cobalamin into its active cofactor forms and delivery to its target enzymes. MMADHC (the methylmalonic aciduria and homocystinuria type D protein), commonly referred to as CblD, is a key chaperone involved in intracellular cobalamin trafficking, and mutations in CblD cause methylmalonic aciduria and/or homocystinuria. Herein, we report the first crystal structure of the globular C-terminal domain of human CblD, which is sufficient for its interaction with MMADHC (the methylmalonic aciduria and homocystinuria type C protein), or CblC, and for supporting the cytoplasmic cobalamin trafficking pathway. CblD contains an α+β fold that is structurally reminiscent of the nitro-FMN reductase superfamily. Two of the closest structural relatives of CblD are CblC, a multifunctional enzyme important for cobalamin trafficking, and the activation domain of methionine synthase. CblD, CblC, and the activation domain of methionine synthase share several distinguishing features and, together with two recently described corrinoid-dependent reductive dehalogenases, constitute a new subclass within the nitro-FMN reductase superfamily. We demonstrate that CblD enhances oxidation of cob(II)alamin bound to CblC and that disease-causing mutations in CblD impair the kinetics of this reaction. The striking structural similarity of CblD to CblC, believed to be contiguous in the cobalamin trafficking pathway, suggests the co-option of molecular mimicry as a strategy for achieving its function. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Structural basis of the inhibition of class C acid phosphatases by adenosine 5;#8242;-phosphorothioate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Harkewal; Reilly, Thomas J.; Tanner, John J.

2012-01-20

The inhibition of phosphatases by adenosine 5'-phosphorothioate (AMPS) was first reported in the late 1960s; however, the structural basis for the inhibition has remained unknown. Here, it is shown that AMPS is a submicromolar inhibitor of class C acid phosphatases, a group of bacterial outer membrane enzymes belonging to the haloacid dehalogenase structural superfamily. Furthermore, the 1.35-{angstrom} resolution crystal structure of the inhibited recombinant Haemophilus influenzae class C acid phosphatase was determined; this is the first structure of a phosphatase complexed with AMPS. The conformation of AMPS is identical to that of the substrate 5'-AMP, except that steric factors forcemore » a rotation of the thiophosphoryl out of the normal phosphoryl-binding pocket. This conformation is catalytically nonproductive, because the P atom is not positioned optimally for nucleophilic attack by Asp64, and the O atom of the scissile O-P bond is too far from the Asp (Asp66) that protonates the leaving group. The structure of 5'-AMP complexed with the Asp64 {yields} Asn mutant enzyme was also determined at 1.35-{angstrom} resolution. This mutation induces the substrate to adopt the same nonproductive binding mode that is observed in the AMPS complex. In this case, electrostatic considerations, rather than steric factors, underlie the movement of the phosphoryl. The structures not only provide an explanation for the inhibition by AMPS, but also highlight the precise steric and electrostatic requirements of phosphoryl recognition by class C acid phosphatases. Moreover, the structure of the Asp64 {yields} Asn mutant illustrates how a seemingly innocuous mutation can cause an unexpected structural change.« less

Streptomyces sp. is a powerful biotechnological tool for the biodegradation of HCH isomers: biochemical and molecular basis.

PubMed

Cuozzo, S A; Sineli, P E; Davila Costa, J; Tortella, G

2018-08-01

Actinobacteria are well-known degraders of toxic materials that have the ability to tolerate and remove organochloride pesticides; thus, they are used for bioremediation. The biodegradation of organochlorines by actinobacteria has been demonstrated in pure and mixed cultures with the concomitant production of metabolic intermediates including γ-pentachlorocyclohexene (γ-PCCH); 1,3,4,6-tetrachloro-1,4-cyclohexadiene (1,4-TCDN); 1,2-dichlorobenzene (1,2-DCB), 1,3-dichlorobenzene (1,3-DCB), or 1,4-dichlorobenzene (1,4-DCB); 1,2,3-trichlorobenzene (1,2,3-TCB), 1,2,4-trichlorobenzene (1,2,4-TCB), or 1,3,5-trichlorobenzene (1,3,5-TCB); 1,3-DCB; and 1,2-DCB. Chromatography coupled to mass spectrometric detection, especially GC-MS, is typically used to determine HCH-isomer metabolites. The important enzymes involved in HCH isomer degradation metabolic pathways include hexachlorocyclohexane dehydrochlorinase (LinA), haloalkane dehalogenase (LinB), and alcohol dehydrogenase (LinC). The metabolic versatility of these enzymes is known. Advances have been made in the identification of actinobacterial haloalkane dehydrogenase, which is encoded by linB. This knowledge will permit future improvements in biodegradation processes using Actinobacteria. The enzymatic and genetic characterizations of the molecular mechanisms involved in these processes have not been fully elucidated, necessitating further studies. New advances in this area suggest promising results. The scope of this paper encompasses the following: (i) the aerobic degradation pathways of hexachlorocyclohexane (HCH) isomers; (ii) the important genes and enzymes involved in the metabolic pathways of HCH isomer degradation; and (iii) the identification and quantification of intermediate metabolites through gas chromatography coupled to mass spectrometry (GC-MS).

Phosphorylation Regulates the Ubiquitin-independent Degradation of Yeast Pah1 Phosphatidate Phosphatase by the 20S Proteasome*

PubMed Central

Hsieh, Lu-Sheng; Su, Wen-Min; Han, Gil-Soo; Carman, George M.

2015-01-01

Saccharomyces cerevisiae Pah1 phosphatidate phosphatase, which catalyzes the conversion of phosphatidate to diacylglycerol for triacylglycerol synthesis and simultaneously controls phosphatidate levels for phospholipid synthesis, is subject to the proteasome-mediated degradation in the stationary phase of growth. In this study, we examined the mechanism for its degradation using purified Pah1 and isolated proteasomes. Pah1 expressed in S. cerevisiae or Escherichia coli was not degraded by the 26S proteasome, but by its catalytic 20S core particle, indicating that its degradation is ubiquitin-independent. The degradation of Pah1 by the 20S proteasome was dependent on time and proteasome concentration at the pH optimum of 7.0. The 20S proteasomal degradation was conserved for human lipin 1 phosphatidate phosphatase. The degradation analysis using Pah1 truncations and its fusion with GFP indicated that proteolysis initiates at the N- and C-terminal unfolded regions. The folded region of Pah1, in particular the haloacid dehalogenase-like domain containing the DIDGT catalytic sequence, was resistant to the proteasomal degradation. The structural change of Pah1, as reflected by electrophoretic mobility shift, occurs through its phosphorylation by Pho85-Pho80, and the phosphorylation sites are located within its N- and C-terminal unfolded regions. Phosphorylation of Pah1 by Pho85-Pho80 inhibited its degradation, extending its half-life by ∼2-fold. The dephosphorylation of endogenously phosphorylated Pah1 by the Nem1-Spo7 protein phosphatase, which is highly specific for the sites phosphorylated by Pho85-Pho80, stimulated the 20S proteasomal degradation and reduced its half-life by 2.6-fold. These results indicate that the proteolysis of Pah1 by the 20S proteasome is controlled by its phosphorylation state. PMID:25809482

Dichloromethane biodegradation in multi-contaminated groundwater: Insights from biomolecular and compound-specific isotope analyses.

PubMed

Hermon, L; Denonfoux, J; Hellal, J; Joulian, C; Ferreira, S; Vuilleumier, S; Imfeld, G

2018-05-31

Dichloromethane (DCM) is a widespread and toxic industrial solvent which often co-occurs with chlorinated ethenes at polluted sites. Biodegradation of DCM occurs under both oxic and anoxic conditions in soils and aquifers. Here we investigated in situ and ex situ biodegradation of DCM in groundwater sampled from the industrial site of Themeroil (France), where DCM occurs as a major co-contaminant of chloroethenes. Carbon isotopic fractionation (ε C ) for DCM ranging from -46 to -22‰ were obtained under oxic or denitrifying conditions, in mineral medium or contaminated groundwater, and for laboratory cultures of Hyphomicrobium sp. strain GJ21 and two new DCM-degrading strains isolated from the contaminated groundwater. The extent of DCM biodegradation (B%) in the aquifer, as evaluated by compound-specific isotope analysis (δ 13 C), ranged from 1% to 85% applying DCM-specific ε C derived from reference strains and those determined in this study. Laboratory groundwater microcosms under oxic conditions showed DCM biodegradation rates of up to 0.1 mM·day -1 , with concomitant chloride release. Dehalogenase genes dcmA and dhlA involved in DCM biodegradation ranged from below 4 × 10 2 (boundary) to 1 × 10 7 (source zone) copies L -1 across the contamination plume. High-throughput sequencing on the 16S rrnA gene in groundwater samples showed that both contaminant level and terminal electron acceptor processes (TEAPs) influenced the distribution of genus-level taxa associated with DCM biodegradation. Taken together, our results demonstrate the potential of DCM biodegradation in multi-contaminated groundwater. This integrative approach may be applied to contaminated aquifers in the future, in order to identify microbial taxa and pathways associated with DCM biodegradation in relation to redox conditions and co-contamination levels. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinetic and Structural Characterization of a Heterohexamer 4-Oxalocrotonate Tautomerase from Chloroflexus aurantiacus J-10-fl: Implications for Functional and Structural Diversity in the Tautomerase Superfamily

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burks, Elizabeth A.; Fleming, Christopher D.; Mesecar, Andrew D.

2010-09-30

4-Oxalocrotonate tautomerase (4-OT) isozymes play prominent roles in the bacterial utilization of aromatic hydrocarbons as sole carbon sources. These enzymes catalyze the conversion of 2-hydroxy-2,4-hexadienedioate (or 2-hydroxymuconate) to 2-oxo-3-hexenedioate, where Pro-1 functions as a general base and shuttles a proton from the 2-hydroxyl group of the substrate to the C-5 position of the product. 4-OT, a homohexamer from Pseudomonas putida mt-2, is the most extensively studied 4-OT isozyme and the founding member of the tautomerase superfamily. A search of five thermophilic bacterial genomes identified a coded amino acid sequence in each that had been annotated as a tautomerase-like protein butmore » lacked Pro-1. However, a nearby sequence has Pro-1, but the sequence is not annotated as a tautomerase-like protein. To characterize this group of proteins, two genes from Chloroflexus aurantiacus J-10-fl were cloned, and the corresponding proteins were expressed. Kinetic, biochemical, and X-ray structural analyses show that the two expressed proteins form a functional heterohexamer 4-OT (hh4-OT), composed of three {alpha}{beta} dimers. Like the P. putida enzyme, hh4-OT requires the amino-terminal proline and two arginines for the conversion of 2-hydroxymuconate to the product, implicating an analogous mechanism. In contrast to 4-OT, hh4-OT does not exhibit the low-level activity of another tautomerase superfamily member, the heterohexamer trans-3-chloroacrylic acid dehalogenase (CaaD). Characterization of hh4-OT enables functional assignment of the related enzymes, highlights the diverse ways the {beta}-{alpha}-{beta} building block can be assembled into an active enzyme, and provides further insight into the molecular basis of the low-level CaaD activity in 4-OT.« less

Diversity of hydrolases from hydrothermal vent sediments of the Levante Bay, Vulcano Island (Aeolian archipelago) identified by activity-based metagenomics and biochemical characterization of new esterases and an arabinopyranosidase.

PubMed

Placido, Antonio; Hai, Tran; Ferrer, Manuel; Chernikova, Tatyana N; Distaso, Marco; Armstrong, Dale; Yakunin, Alexander F; Toshchakov, Stepan V; Yakimov, Michail M; Kublanov, Ilya V; Golyshina, Olga V; Pesole, Graziano; Ceci, Luigi R; Golyshin, Peter N

2015-12-01

A metagenomic fosmid expression library established from environmental DNA (eDNA) from the shallow hot vent sediment sample collected from the Levante Bay, Vulcano Island (Aeolian archipelago) was established in Escherichia coli. Using activity-based screening assays, we have assessed 9600 fosmid clones corresponding to approximately 350 Mbp of the cloned eDNA, for the lipases/esterases/lactamases, haloalkane and haloacid dehalogenases, and glycoside hydrolases. Thirty-four positive fosmid clones were selected from the total of 120 positive hits and sequenced to yield ca. 1360 kbp of high-quality assemblies. Fosmid inserts were attributed to the members of ten bacterial phyla, including Proteobacteria, Bacteroidetes, Acidobateria, Firmicutes, Verrucomicrobia, Chloroflexi, Spirochaetes, Thermotogae, Armatimonadetes, and Planctomycetes. Of ca. 200 proteins with high biotechnological potential identified therein, we have characterized in detail three distinct α/β-hydrolases (LIPESV12_9, LIPESV12_24, LIPESV12_26) and one new α-arabinopyranosidase (GLV12_5). All LIPESV12 enzymes revealed distinct substrate specificities tested against 43 structurally diverse esters and 4 p-nitrophenol carboxyl esters. Of 16 different glycosides tested, the GLV12_5 hydrolysed only p-nitrophenol-α-(L)-arabinopyranose with a high specific activity of about 2.7 kU/mg protein. Most of the α/β-hydrolases were thermophilic and revealed a high tolerance to, and high activities in the presence of, numerous heavy metal ions. Among them, the LIPESV12_24 was the best temperature-adapted, retaining its activity after 40 min of incubation at 90 °C. Furthermore, enzymes were active in organic solvents (e.g., >30% methanol). Both LIPESV12_24 and LIPESV12_26 had the GXSXG pentapeptides and the catalytic triads Ser-Asp-His typical to the representatives of carboxylesterases of EC 3.1.1.1.

Enzymes involved in the biodegradation of hexachlorocyclohexane: a mini review.

PubMed

Camacho-Pérez, Beni; Ríos-Leal, Elvira; Rinderknecht-Seijas, Noemí; Poggi-Varaldo, Héctor M

2012-03-01

The scope of this paper encompasses the following subjects: (i) aerobic and anaerobic degradation pathways of γ-hexachlorocyclohexane (HCH); (ii) important genes and enzymes involved in the metabolic pathways of γ-HCH degradation; (iii) the instrumental methods for identifying and quantifying intermediate metabolites, such as gas chromatography coupled to mass spectrometry (GC-MS) and other techniques. It can be concluded that typical anaerobic and aerobic pathways of γ-HCH are well known for a few selected microbial strains, although less is known for anaerobic consortia where the possibility of synergism, antagonism, and mutualism can lead to more particular routes and more effective degradation of γ-HCH. Conversion and removals in the range 39%-100% and 47%-100% have been reported for aerobic and anaerobic cultures, respectively. Most common metabolites reported for aerobic degradation of lindane are γ-pentachlorocyclohexene (γ-PCCH), 2,5-dichlorobenzoquinone (DCBQ), Chlorohydroquinone (CHQ), chlorophenol, and phenol, whereas PCCH, isomers of trichlorobenzene (TCB), chlorobenzene, and benzene are the most typical metabolites found in anaerobic pathways. Enzyme and genetic characterization of the involved molecular mechanisms are in their early infancy; more work is needed to elucidate them in the future. Advances have been made on identification of enzymes of Sphingomonas paucimobilis where the gene LinB codifies for the enzyme haloalkane dehalogenase that acts on 1,3,4,6-tetrachloro 1,4-cyclohexadiene, thus debottlenecking the pathway. Other more common enzymes such as phenol hydroxylase, catechol 1,2-dioxygenase, catechol 2,3-dioxygenase are also involved since they attack intermediate metabolites of lindane such as catechol and less substituted chlorophenols. Chromatography coupled to mass spectrometric detector, especially GC-MS, is the most used technique for resolving for γ-HCH metabolites, although there is an increased participation of HPLC-MS methods. Scintillation methods are very useful to assess final degradation of γ-HCH. Copyright © 2011 Elsevier Ltd. All rights reserved.

Biological Chlorine Cycling in Arctic Peat Soils

NASA Astrophysics Data System (ADS)

Zlamal, J. E.; Raab, T. K.; Lipson, D.

2014-12-01

Soils of the Arctic tundra near Barrow, Alaska are waterlogged and anoxic throughout most of the profile due to underlying permafrost. Microbial communities in these soils are adapted for the dominant anaerobic conditions and are capable of a surprising diversity of metabolic pathways. Anaerobic respiration in this environment warrants further study, particularly in the realm of electron cycling involving chlorine, which preliminary data suggest may play an important role in arctic anaerobic soil respiration. For decades, Cl was rarely studied outside of the context of solvent-contaminated sites due to the widely held belief that it is an inert element. However, Cl has increasingly become recognized as a metabolic player in microbial communities and soil cycling processes. Organic chlorinated compounds (Clorg) can be made by various organisms and used metabolically by others, such as serving as electron acceptors for microbes performing organohalide respiration. Sequencing our arctic soil samples has uncovered multiple genera of microorganisms capable of participating in many Cl-cycling processes including organohalide respiration, chlorinated hydrocarbon degradation, and perchlorate reduction. Metagenomic analysis of these soils has revealed genes for key enzymes of Cl-related metabolic processes such as dehalogenases and haloperoxidases, and close matches to genomes of known organohalide respiring microorganisms from the Dehalococcoides, Dechloromonas, Carboxydothermus, and Anaeromyxobacter genera. A TOX-100 Chlorine Analyzer was used to quantify total Cl in arctic soils, and these data were examined further to separate levels of inorganic Cl compounds and Clorg. Levels of Clorg increased with soil organic matter content, although total Cl levels lack this trend. X-ray Absorption Near Edge Structure (XANES) was used to provide information on the structure of Clorg in arctic soils, showing great diversity with Cl bound to both aromatic and alkyl groups. Incubations were conducted in the laboratory providing arctic soils with Clorg, and measurements taken to assess rates of organohalide respiration show an increase in chloride production due to microbial activity. Investigating these soils with diverse techniques affirms the importance of Cl-cycling in a pristine arctic tundra ecosystem.

Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation.

PubMed

Sutton, Nora B; Atashgahi, Siavash; Saccenti, Edoardo; Grotenhuis, Tim; Smidt, Hauke; Rijnaarts, Huub H M

2015-01-01

While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the abundance of organohalide respiring bacteria (OHRB) and reductive dehalogenase (rdh) genes using quantitative PCR, and microbial community composition through sequencing of 16S rRNA genes. A PCE degrading enrichment was repeatedly treated with low (25 μmol), medium (50 μmol), or high (100 μmol) permanganate doses, or no oxidant treatment (biotic control). Low and medium treatments led to higher OHR rates and enrichment of several OHRB and rdh genes, as compared to the biotic control. Improved degradation rates can be attributed to enrichment of (1) OHRB able to also utilize Mn oxides as a terminal electron acceptor and (2) non-dechlorinating community members of the Clostridiales and Deltaproteobacteria possibly supporting OHRB by providing essential co-factors. In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control. High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB. Although OTUs classified within the OHR-supportive order Clostridiales and OHRB increased in abundance over the course of 213 days following the final 100 μmol permanganate treatment, only limited regeneration of PCE dechlorination was observed in one of three microcosms, suggesting strong chemical oxidation treatments can irreversibly disrupt OHR. Overall, this detailed investigation into dose-dependent changes of microbial composition and activity due to permanganate treatment provides insight into the mechanisms of OHR stimulation or disruption upon chemical oxidation.

Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation

PubMed Central

Sutton, Nora B.; Atashgahi, Siavash; Saccenti, Edoardo; Grotenhuis, Tim; Smidt, Hauke; Rijnaarts, Huub H. M.

2015-01-01

While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the abundance of organohalide respiring bacteria (OHRB) and reductive dehalogenase (rdh) genes using quantitative PCR, and microbial community composition through sequencing of 16S rRNA genes. A PCE degrading enrichment was repeatedly treated with low (25 μmol), medium (50 μmol), or high (100 μmol) permanganate doses, or no oxidant treatment (biotic control). Low and medium treatments led to higher OHR rates and enrichment of several OHRB and rdh genes, as compared to the biotic control. Improved degradation rates can be attributed to enrichment of (1) OHRB able to also utilize Mn oxides as a terminal electron acceptor and (2) non-dechlorinating community members of the Clostridiales and Deltaproteobacteria possibly supporting OHRB by providing essential co-factors. In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2–4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control. High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB. Although OTUs classified within the OHR-supportive order Clostridiales and OHRB increased in abundance over the course of 213 days following the final 100 μmol permanganate treatment, only limited regeneration of PCE dechlorination was observed in one of three microcosms, suggesting strong chemical oxidation treatments can irreversibly disrupt OHR. Overall, this detailed investigation into dose-dependent changes of microbial composition and activity due to permanganate treatment provides insight into the mechanisms of OHR stimulation or disruption upon chemical oxidation. PMID:26244346

Loop-Mediated Isothermal Amplification (LAMP) for Rapid Detection and Quantification of Dehalococcoides Biomarker Genes in Commercial Reductive Dechlorinating Cultures KB-1 and SDC-9

PubMed Central

Kanitkar, Yogendra H.; Stedtfeld, Robert D.; Steffan, Robert J.; Hashsham, Syed A.

2016-01-01

Real-time quantitative PCR (qPCR) protocols specific to the reductive dehalogenase (RDase) genes vcrA, bvcA, and tceA are commonly used to quantify Dehalococcoides spp. in groundwater from chlorinated solvent-contaminated sites. In this study, loop-mediated isothermal amplification (LAMP) was developed as an alternative approach for the quantification of these genes. LAMP does not require a real-time thermal cycler (i.e., amplification is isothermal), allowing the method to be performed using less-expensive and potentially field-deployable detection devices. Six LAMP primers were designed for each of three RDase genes (vcrA, bvcA, and tceA) using Primer Explorer V4. The LAMP assays were compared to conventional qPCR approaches using plasmid standards, two commercially available bioaugmentation cultures, KB-1 and SDC-9 (both contain Dehalococcoides species). DNA was extracted over a growth cycle from KB-1 and SDC-9 cultures amended with trichloroethene and vinyl chloride, respectively. All three genes were quantified for KB-1, whereas only vcrA was quantified for SDC-9. A comparison of LAMP and qPCR using standard plasmids indicated that quantification results were similar over a large range of gene concentrations. In addition, the quantitative increase in gene concentrations over one growth cycle of KB-1 and SDC-9 using LAMP was comparable to that of qPCR. The developed LAMP assays for vcrA and tceA genes were validated by comparing quantification on the Gene-Z handheld platform and a real-time thermal cycler using DNA isolated from eight groundwater samples obtained from an SDC-9-bioaugmented site (Tulsa, OK). These assays will be particularly useful at sites subject to bioaugmentation with these two commonly used Dehalococcoides species-containing cultures. PMID:26746711

Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE-DNAPL source zone

NASA Astrophysics Data System (ADS)

Cápiro, Natalie L.; Löffler, Frank E.; Pennell, Kurt D.

2015-11-01

Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE-DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis-1,2-dichloroethene (cis-DCE) formation after 1 PV (ca. 7 days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90 μM) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0 ± 1.3 and 4.0 ± 1.7 fold in the pool and ganglia regions, respectively. Dhc and GeoSZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE-DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (≥ 155 μM) and ethene (≥ 65 μM) concentrations were measured in zones where Dhc and GeoSZ were predominately attached to the solids. These findings demonstrate dynamic responses of organohalide-respiring bacteria in a heterogeneous DNAPL source zone, and emphasize the influence of source zone architecture on bioremediation performance.

Metabolism of 4-chloro-2-nitrophenol in a Gram-positive bacterium, Exiguobacterium sp. PMA

PubMed Central

2012-01-01

Background Chloronitrophenols (CNPs) are widely used in the synthesis of dyes, drugs and pesticides, and constitute a major group of environmental pollutants. 4-Chloro-2-nitrophenol (4C2NP) is an isomer of CNPs that has been detected in various industrial effluents. A number of physicochemical methods have been used for treatment of wastewater containing 4C2NP. These methods are not as effective as microbial degradation, however. Results A 4C2NP-degrading bacterium, Exiguobacterium sp. PMA, which uses 4C2NP as the sole carbon and energy source was isolated from a chemically-contaminated site in India. Exiguobacterium sp. PMA degraded 4C2NP with the release of stoichiometeric amounts of chloride and ammonium ions. The effects of different substrate concentrations and various inoculum sizes on degradation of 4C2NP were investigated. Exiguobacterium sp. PMA degraded 4C2NP up to a concentration of 0.6 mM. High performance liquid chromatography and gas chromatography–mass spectrometry identified 4-chloro-2-aminophenol (4C2AP) and 2-aminophenol (2AP) as possible metabolites of the 4C2NP degradation pathway. The crude extract of 4C2NP-induced PMA cells contained enzymatic activity for 4C2NP reductase and 4C2AP dehalogenase, suggesting the involvement of these enzymes in the degradation of 4C2NP. Microcosm studies using sterile and non-sterile soils spiked with 4C2NP were carried out to monitor the bioremediation potential of Exiguobacterium sp. PMA. The bioremediation of 4C2NP by Exiguobacterium sp. PMA was faster in non-sterilized soil than sterilized soil. Conclusions Our studies indicate that Exiguobacterium sp. PMA may be useful for the bioremediation of 4C2NP-contaminated sites. This is the first report of (i) the formation of 2AP in the 4C2NP degradation pathway by any bacterium and (iii) the bioremediation of 4C2NP by any bacterium. PMID:23171039

Metabolism of 4-chloro-2-nitrophenol in a gram-positive bacterium, Exiguobacterium sp. PMA.

PubMed

Arora, Pankaj Kumar; Sharma, Ashutosh; Mehta, Richa; Shenoy, Belle Damodara; Srivastava, Alok; Singh, Vijay Pal

2012-11-21

Chloronitrophenols (CNPs) are widely used in the synthesis of dyes, drugs and pesticides, and constitute a major group of environmental pollutants. 4-Chloro-2-nitrophenol (4C2NP) is an isomer of CNPs that has been detected in various industrial effluents. A number of physicochemical methods have been used for treatment of wastewater containing 4C2NP. These methods are not as effective as microbial degradation, however. A 4C2NP-degrading bacterium, Exiguobacterium sp. PMA, which uses 4C2NP as the sole carbon and energy source was isolated from a chemically-contaminated site in India. Exiguobacterium sp. PMA degraded 4C2NP with the release of stoichiometeric amounts of chloride and ammonium ions. The effects of different substrate concentrations and various inoculum sizes on degradation of 4C2NP were investigated. Exiguobacterium sp. PMA degraded 4C2NP up to a concentration of 0.6 mM. High performance liquid chromatography and gas chromatography-mass spectrometry identified 4-chloro-2-aminophenol (4C2AP) and 2-aminophenol (2AP) as possible metabolites of the 4C2NP degradation pathway. The crude extract of 4C2NP-induced PMA cells contained enzymatic activity for 4C2NP reductase and 4C2AP dehalogenase, suggesting the involvement of these enzymes in the degradation of 4C2NP. Microcosm studies using sterile and non-sterile soils spiked with 4C2NP were carried out to monitor the bioremediation potential of Exiguobacterium sp. PMA. The bioremediation of 4C2NP by Exiguobacterium sp. PMA was faster in non-sterilized soil than sterilized soil. Our studies indicate that Exiguobacterium sp. PMA may be useful for the bioremediation of 4C2NP-contaminated sites. This is the first report of (i) the formation of 2AP in the 4C2NP degradation pathway by any bacterium and (iii) the bioremediation of 4C2NP by any bacterium.

Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation: Comparison of in vitro and in silico results.

PubMed

Heeb, Norbert V; Mazenauer, Manuel; Wyss, Simon; Geueke, Birgit; Kohler, Hans-Peter E; Lienemann, Peter

2018-05-12

LinB is a haloalkane dehalogenase found in Sphingobium indicum B90A, an aerobic bacterium isolated from contaminated soils of hexachlorocyclohexane (HCH) dumpsites. We showed that this enzyme also converts hexabromocyclododecanes (HBCDs). Here we give new insights in the kinetics and stereochemistry of the enzymatic transformation of δ-HBCD, which resulted in the formation of two pentabromocyclododecanols (PBCDols) as first- (P 1δ , P 2δ ) and two tetrabromocyclododecadiols (TBCDdiols) as second-generation products (T 1δ , T 2δ ). Enzymatic transformations of δ-HBCD, α 1 -PBCDol, one of the transformation products, and α 2 -PBCDol, its enantiomer, were studied and modeled with Michaelis-Menten (MM) kinetics. Respective MM-parameters K M , v max , k cat /K M indicated that δ-HBCD is the best LinB substrate followed by α 2 - and α 1 -PBCDol. The stereochemistry of these transformations was modeled in silico, investigating respective enzyme-substrate (ES) and enzyme-product (EP) complexes. One of the four predicted ES-complexes led to the PBCDol product P 1δ , identical to α 2 -PBCDol with the 1R,2R,5S,6R,9R,10S-configuration. An S N 2-like substitution of bromine at C6 of δ-HBCD by Asp-108 of LinB and subsequent hydrolysis of the alkyl-enzyme led to α 2 -PBCDol. Modeling results further indicate that backside attacks at C1, C9 and C10 are reasonable too, selectively binding leaving bromide ions in a halide pocket found in LinB. Docking with α 2 -PBCDol, also allowed productive enzyme binding. A TBCD-1,5-diol with the 1S,2S,5R,6R,9S,10R-configuration is the predicted second-generation product T 1δ . In conclusion, in vitro- and in silico findings now allow a detailed description of step-wise enzymatic dehalohydroxylation reactions of δ-HBCD to specific PBCDols and TBCDdiols at Å-resolution and predictions of their stereochemistry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genomic and Transcriptomic Analysis of Growth-Supporting Dehalogenation of Chlorinated Methanes in Methylobacterium

PubMed Central

Chaignaud, Pauline; Maucourt, Bruno; Weiman, Marion; Alberti, Adriana; Kolb, Steffen; Cruveiller, Stéphane; Vuilleumier, Stéphane; Bringel, Françoise

2017-01-01

Bacterial adaptation to growth with toxic halogenated chemicals was explored in the context of methylotrophic metabolism of Methylobacterium extorquens, by comparing strains CM4 and DM4, which show robust growth with chloromethane and dichloromethane, respectively. Dehalogenation of chlorinated methanes initiates growth-supporting degradation, with intracellular release of protons and chloride ions in both cases. The core, variable and strain-specific genomes of strains CM4 and DM4 were defined by comparison with genomes of non-dechlorinating strains. In terms of gene content, adaptation toward dehalogenation appears limited, strains CM4 and DM4 sharing between 75 and 85% of their genome with other strains of M. extorquens. Transcript abundance in cultures of strain CM4 grown with chloromethane and of strain DM4 grown with dichloromethane was compared to growth with methanol as a reference C1 growth substrate. Previously identified strain-specific dehalogenase-encoding genes were the most transcribed with chlorinated methanes, alongside other genes encoded by genomic islands (GEIs) and plasmids involved in growth with chlorinated compounds as carbon and energy source. None of the 163 genes shared by strains CM4 and DM4 but not by other strains of M. extorquens showed higher transcript abundance in cells grown with chlorinated methanes. Among the several thousand genes of the M. extorquens core genome, 12 genes were only differentially abundant in either strain CM4 or strain DM4. Of these, 2 genes of known function were detected, for the membrane-bound proton translocating pyrophosphatase HppA and the housekeeping molecular chaperone protein DegP. This indicates that the adaptive response common to chloromethane and dichloromethane is limited at the transcriptional level, and involves aspects of the general stress response as well as of a dehalogenation-specific response to intracellular hydrochloric acid production. Core genes only differentially abundant in either strain CM4 or strain DM4 total 13 and 58 CDS, respectively. Taken together, the obtained results suggest different transcriptional responses of chloromethane- and dichloromethane-degrading M. extorquens strains to dehalogenative metabolism, and substrate- and pathway-specific modes of growth optimization with chlorinated methanes. PMID:28919881

Homoacetogenesis in Deep-Sea Chloroflexi, as Inferred by Single-Cell Genomics, Provides a Link to Reductive Dehalogenation in Terrestrial Dehalococcoidetes

PubMed Central

Sewell, Holly L.; Kaster, Anne-Kristin

2017-01-01

ABSTRACT The deep marine subsurface is one of the largest unexplored biospheres on Earth and is widely inhabited by members of the phylum Chloroflexi. In this report, we investigated genomes of single cells obtained from deep-sea sediments of the Peruvian Margin, which are enriched in such Chloroflexi. 16S rRNA gene sequence analysis placed two of these single-cell-derived genomes (DscP3 and Dsc4) in a clade of subphylum I Chloroflexi which were previously recovered from deep-sea sediment in the Okinawa Trough and a third (DscP2-2) as a member of the previously reported DscP2 population from Peruvian Margin site 1230. The presence of genes encoding enzymes of a complete Wood-Ljungdahl pathway, glycolysis/gluconeogenesis, a Rhodobacter nitrogen fixation (Rnf) complex, glyosyltransferases, and formate dehydrogenases in the single-cell genomes of DscP3 and Dsc4 and the presence of an NADH-dependent reduced ferredoxin:NADP oxidoreductase (Nfn) and Rnf in the genome of DscP2-2 imply a homoacetogenic lifestyle of these abundant marine Chloroflexi. We also report here the first complete pathway for anaerobic benzoate oxidation to acetyl coenzyme A (CoA) in the phylum Chloroflexi (DscP3 and Dsc4), including a class I benzoyl-CoA reductase. Of remarkable evolutionary significance, we discovered a gene encoding a formate dehydrogenase (FdnI) with reciprocal closest identity to the formate dehydrogenase-like protein (complex iron-sulfur molybdoenzyme [CISM], DET0187) of terrestrial Dehalococcoides/Dehalogenimonas spp. This formate dehydrogenase-like protein has been shown to lack formate dehydrogenase activity in Dehalococcoides/Dehalogenimonas spp. and is instead hypothesized to couple HupL hydrogenase to a reductive dehalogenase in the catabolic reductive dehalogenation pathway. This finding of a close functional homologue provides an important missing link for understanding the origin and the metabolic core of terrestrial Dehalococcoides/Dehalogenimonas spp. and of reductive dehalogenation, as well as the biology of abundant deep-sea Chloroflexi. PMID:29259088

Genomic and Transcriptomic Analysis of Growth-Supporting Dehalogenation of Chlorinated Methanes in Methylobacterium.

PubMed

Chaignaud, Pauline; Maucourt, Bruno; Weiman, Marion; Alberti, Adriana; Kolb, Steffen; Cruveiller, Stéphane; Vuilleumier, Stéphane; Bringel, Françoise

2017-01-01

Bacterial adaptation to growth with toxic halogenated chemicals was explored in the context of methylotrophic metabolism of Methylobacterium extorquens , by comparing strains CM4 and DM4, which show robust growth with chloromethane and dichloromethane, respectively. Dehalogenation of chlorinated methanes initiates growth-supporting degradation, with intracellular release of protons and chloride ions in both cases. The core, variable and strain-specific genomes of strains CM4 and DM4 were defined by comparison with genomes of non-dechlorinating strains. In terms of gene content, adaptation toward dehalogenation appears limited, strains CM4 and DM4 sharing between 75 and 85% of their genome with other strains of M. extorquens . Transcript abundance in cultures of strain CM4 grown with chloromethane and of strain DM4 grown with dichloromethane was compared to growth with methanol as a reference C 1 growth substrate. Previously identified strain-specific dehalogenase-encoding genes were the most transcribed with chlorinated methanes, alongside other genes encoded by genomic islands (GEIs) and plasmids involved in growth with chlorinated compounds as carbon and energy source. None of the 163 genes shared by strains CM4 and DM4 but not by other strains of M. extorquens showed higher transcript abundance in cells grown with chlorinated methanes. Among the several thousand genes of the M. extorquens core genome, 12 genes were only differentially abundant in either strain CM4 or strain DM4. Of these, 2 genes of known function were detected, for the membrane-bound proton translocating pyrophosphatase HppA and the housekeeping molecular chaperone protein DegP. This indicates that the adaptive response common to chloromethane and dichloromethane is limited at the transcriptional level, and involves aspects of the general stress response as well as of a dehalogenation-specific response to intracellular hydrochloric acid production. Core genes only differentially abundant in either strain CM4 or strain DM4 total 13 and 58 CDS, respectively. Taken together, the obtained results suggest different transcriptional responses of chloromethane- and dichloromethane-degrading M. extorquens strains to dehalogenative metabolism, and substrate- and pathway-specific modes of growth optimization with chlorinated methanes.

Selection of clc, cba, and fcb Chlorobenzoate-Catabolic Genotypes from Groundwater and Surface Waters Adjacent to the Hyde Park, Niagara Falls, Chemical Landfill

PubMed Central

Peel, Michelle C.; Wyndham, R. Campbell

1999-01-01

The frequency of isolation of three nonhomologous chlorobenzoate catabolic genotypes (clc, cba, and fcb) was determined for 464 isolates from freshwater sediments and groundwater in the vicinity of the Hyde Park industrial landfill site in the Niagara watershed. Samples were collected from both contaminated and noncontaminated sites during spring, summer, and fall and enriched at 4, 22, or 32°C with micromolar to millimolar concentrations of chlorobenzoates and 3-chlorobiphenyl (M. C. Peel and R. C. Wyndham, Microb. Ecol: 33:59–68, 1997). Hybridization at moderate stringency to restriction-digested genomic DNA with DNA probes revealed the chlorocatechol 1,2-dioxygenase operon (clcABD), the 3-chlorobenzoate 3,4-(4,5)-dioxygenase operon (cbaABC), and the 4-chlorobenzoate dehalogenase (fcbB) gene in isolates enriched from all contaminated sites in the vicinity of the industrial landfill. Nevertheless, the known genes were found in less than 10% of the isolates from the contaminated sites, indicating a high level of genetic diversity in the microbial community. The known genotypes were not enriched from the noncontaminated control sites nearby. The clc, cba, and fcb isolates were distributed across five phenotypically distinct groups based on Biolog carbon source utilization, with the breadth of the host range decreasing in the order clc > cba > fcb. Restriction fragment length polymorphism (RFLP) patterns showed that the cba genes were conserved in all isolates whereas the clc and fcb genes exhibited variation in RFLP patterns. These observations are consistent with the recent spread of the cba genes by horizontal transfer as part of transposon Tn5271 in response to contaminant exposure at Hyde Park. Consistent with this hypothesis, IS1071, the flanking element in Tn5271, was found in all isolates that carried the cba genes. Interestingly, IS1071 was also found in a high proportion of isolates from Hyde Park carrying the clc and fcb genes, as well as in type strains carrying the clcABD operon and the biphenyl (bph) catabolic genes. PMID:10103260

Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE-DNAPL source zone.

PubMed

Cápiro, Natalie L; Löffler, Frank E; Pennell, Kurt D

2015-11-01

Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE-DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis-1,2-dichloroethene (cis-DCE) formation after 1 PV (ca. 7 days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90 μM) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0±1.3 and 4.0±1.7 fold in the pool and ganglia regions, respectively. Dhc and GeoSZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE-DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (≥155 μM) and ethene (≥65 μM) concentrations were measured in zones where Dhc and GeoSZ were predominately attached to the solids. These findings demonstrate dynamic responses of organohalide-respiring bacteria in a heterogeneous DNAPL source zone, and emphasize the influence of source zone architecture on bioremediation performance. Copyright © 2015 Elsevier B.V. All rights reserved.

Chlorinated Electron Acceptor Abundance Drives Selection of Dehalococcoides mccartyi (D. mccartyi) Strains in Dechlorinating Enrichment Cultures and Groundwater Environments

PubMed Central

Pérez-de-Mora, Alfredo; Lacourt, Anna; McMaster, Michaye L.; Liang, Xiaoming; Dworatzek, Sandra M.; Edwards, Elizabeth A.

2018-01-01

Dehalococcoides mccartyi (D. mccartyi) strains differ primarily from one another by the number and identity of the reductive dehalogenase homologous catalytic subunit A (rdhA) genes within their respective genomes. While multiple rdhA genes have been sequenced, the activity of the corresponding proteins has been identified in only a few cases. Examples include the enzymes whose substrates are groundwater contaminants such as trichloroethene (TCE), cis-dichloroethene (cDCE) and vinyl chloride (VC). The associated rdhA genes, namely tceA, bvcA, and vcrA, along with the D. mccartyi 16S rRNA gene are often used as biomarkers of growth in field samples. In this study, we monitored an additional 12 uncharacterized rdhA sequences identified in the metagenome in the mixed D. mccartyi-containing culture KB-1 to monitor population shifts in more detail. Quantitative PCR (qPCR) assays were developed for 15 D. mccartyi rdhA genes and used to measure population diversity in 11 different sub-cultures of KB-1, each enriched on different chlorinated ethenes and ethanes. The proportion of rdhA gene copies relative to D. mccartyi 16S rRNA gene copies revealed the presence of multiple distinct D. mccartyi strains in each culture, many more than the two strains inferred from 16S rRNA analysis. The specific electron acceptor amended to each culture had a major influence on the distribution of D. mccartyi strains and their associated rdhA genes. We also surveyed the abundance of rdhA genes in samples from two bioaugmented field sites (Canada and United Kingdom). Growth of the dominant D. mccartyi strain in KB-1 was detected at the United Kingdom site. At both field sites, the measurement of relative rdhA abundances revealed D. mccartyi population shifts over time as dechlorination progressed from TCE through cDCE to VC and ethene. These shifts indicate a selective pressure of the most abundant chlorinated electron acceptor, as was also observed in lab cultures. These results also suggest that reductive dechlorination at contaminated sites is brought about by multiple strains of D. mccartyi whether or not the site is bioaugmented. Understanding the driving forces behind D. mccartyi population selection and activity is improving predictability of remediation performance at chlorinated solvent contaminated sites.

An Evaluation of Family-Centered Rounds in the PICU: Room for Improvement Suggested by Families and Providers.

PubMed

Levin, Amanda B; Fisher, Kiondra R; Cato, Krista D; Zurca, Adrian D; October, Tessie W

2015-11-01

To identify areas for improvement in family-centered rounds from both the family and provider perspectives. Prospective, cross-sectional mixed-methods study, including an objective measure (direct observation of family-centered rounds) and subjective measures (surveys of English-speaking families and providers) of family-centered rounds. PICU in a single, tertiary children's hospital. Families of children admitted to the PICU, physicians, and nurses. None. Two hundred thirty-two family-centered round encounters were observed over a 10-week period. Family-centered round encounters averaged 10.5 minutes per child. Multivariable regression analysis revealed that family presence was independently associated with length of family-centered rounds (p < 0.002) despite family talk time accounting for an average of 25 seconds (4%) of the encounter. Non-English-speaking families were less likely to attend family-centered rounds compared with English-speaking families even when physically present at the patient's bedside (p < 0.001). Most commonly families and providers agreed that family-centered rounds keep the family informed and reported positive statements about family presence on family-centered rounds; however, PICU fellows did not agree that families provided pertinent information and nurses reported that family presence limited patient discussions. The primary advice families offered providers to improve family-centered rounds was to be more considerate and courteous, including accommodating family schedules, minimizing distractions, and limiting computer viewing. Family presence increased the length of family-centered rounds despite a small percentage of time spoken by families, suggesting longer rounds are due to changes in provider behavior when families are present. Also, non-English-speaking families may need more support to be able to attend and benefit from family-centered rounds. Lastly, in an era of full family-centered rounds acceptance, families and most providers, except fellows, report benefit from family presence during family-centered rounds. However, providers should be aware of the perception of their behaviors to optimize the experience for families.

Patterns of family management of childhood chronic conditions and their relationship to child and family functioning.

PubMed

Knafl, Kathleen A; Deatrick, Janet A; Knafl, George J; Gallo, Agatha M; Grey, Margaret; Dixon, Jane

2013-01-01

Understanding patterns of family response to childhood chronic conditions provides a more comprehensive understanding of their influence on family and child functioning. In this paper, we report the results of a cluster analysis based on the six scales comprising the Family Management Measure (FaMM) and the resulting typology of family management. The sample of 575 parents (414 families) of children with diverse chronic conditions fell into four patterns of response (Family Focused, Somewhat Family Focused, Somewhat Condition Focused, Condition Focused) that differed in the extent family life was focused on usual family routines or the demands of condition management. Most (57%) families were in either the Family Focused or Somewhat Family Focused pattern. Patterns of family management were related significantly to family and child functioning, with families in the Family Focused and Somewhat Family Focused patterns demonstrating significantly better family and child functioning than families in the other two patterns. Copyright © 2013. Published by Elsevier Inc.

Factors associated with family-centered involvement in family practice--a cross-sectional multivariate analysis.

PubMed

Deutsch, Tobias; Frese, Thomas; Sandholzer, Hagen

2014-01-01

The importance of a family-centered approach in family practice has been emphasized. Knowledge about factors associated with higher family-centered involvement seems beneficial to stimulate its realization. German office-based family physicians completed a questionnaire addressing several aspects of family-centered care. Logistic regression was used to identify associations with the involvement overall and in different domains: routine inquiry and documentation of family-related information, family orientation regarding diagnosis and treatment, family-oriented dialogues, family conferences, and case-related collaboration with marriage and family therapists. We found significant associations between physicians' family-centered involvement and expected patient receptiveness, perceived impact of the family's influence on health, self-perceived psychosocial family-care competences (overall and concerning concepts for family orientation, psychosocial intervention in family conferences, and the communication of the idea of family counseling), advanced training in psychosocial primary care (PPC), personal acquaintance with family therapists (regarding case-related collaboration), and rural office environment. Increased emphasis on the family's influence on health in medical education and training, the provision of concepts for a family-centered perspective, and versatile skills for psychosocial intervention and inquiry of patient preferences, as well as the strengthening of networking between family physicians and family therapists, might promote the family-centered approach in family practice.

Methodological issues in interviewing families in family nursing research.

PubMed

Astedt-Kurki, P; Paavilainen, E; Lehti, K

2001-07-01

The aim of this study is to discuss what methodological problems can be met in family research with one family member as an interviewee speaking on behalf of the whole family and, vice versa, what is the meaning of having multiple family members or the whole family unit as informants. Family nursing research is part of multidisciplinary research with families. It is a basis for family nursing and contributes to research, especially from the perspective of family welfare and its promotion. Family nursing research generates knowledge concerning families' and family members' wellbeing and experiences and expectations of nursing and health care. The examination of methodological problems while pursuing family research is based on two studies conducted in Finland. Quantitative methods add to the general knowledge of families. Qualitative methods are well suited to the study of family experiences. Family interviews performed for research purposes differ from interviews aiming at caring for families. They aim at obtaining knowledge of families on a general level so as to improve family nursing. Family research has to be looked at as a whole. It faces many challenges such as the definition of the family, gaining access, methods of data collection and data management. A family is a complex system and research with families need flexible, sensitive and practical methods. Family research should also aim at developing new methods for data collection and analysis.

Family demands, social support and family functioning in Taiwanese families rearing children with Down syndrome.

PubMed

Hsiao, C-Y

2014-06-01

Down syndrome (DS) affects not only children but also their families. Much remains to be learned about factors that influence how families of children with DS function, especially families in non-Western populations. The purpose of this cross-sectional, correlational study was to examine how family demographics, family demands and social support relate to family functioning as well as the potential mediating effect of social support on the relationship between family demands and family functioning in Taiwanese families of children with DS. One hundred and fifty-five parents (80 mothers and 75 fathers) from 83 families independently completed mailed questionnaires. Data were analysed using a principal component analysis and mixed linear modelling. Families having older children with DS, greater parental education, higher family income, fewer family demands and greater social support contributed to healthier family functioning. Social support partially mediated the effects of family demands on family functioning. Family demographics, family demands and social support appear to be important factors that may play a critical role in how Taiwanese families respond to the birth of a child with DS. Care of children with DS and their families is likely to be more effective if professionals working with these families are aware of factors that contribute to healthy family functioning. © 2013 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Patterns of Family Management of Childhood Chronic Conditions and Their Relationship to Child and Family Functioning

PubMed Central

Knafl, Kathleen A.; Deatrick, Janet A.; Knafl, George J.; Gallo, Agatha M.; Grey, Margaret; Dixon, Jane

2015-01-01

Understanding patterns of family response to childhood chronic conditions based on a configuration of multiple variables or qualitative themes provides a comprehensive understanding of health-related challenges and their influence on family and child functioning. In this paper, we used the six scales comprising the Family Management Measure (FaMM) in a cluster analysis to describe a typology of family management and data from other measures of child and family functioning to validate and explain those clusters. The sample of 575 parents from 414 families of children who had diverse chronic conditions endorsed four patterns of response (Family Focused, Somewhat Family Focused, Somewhat Condition Focused, Condition Focused). We also considered the extent to which couples had shared or discrepant views of family management. Most (57%) families were in either the Family Focused or Somewhat Family Focused pattern. Single mothers were significantly less likely to be in the two patterns reflecting greater ease in family management and significantly more likely to be in the two patterns reflecting more difficulty. Patterns of family management were related significantly to family and child functioning, with families in the Family Focused and Somewhat Family Focused patterns demonstrating significantly better family and child functioning than families in the other two patterns. PMID:23602651

The ideology of small family.

PubMed

Lakshminarayana, H D

1991-01-01

Data are obtained and analyzed from 4232 rural families of handloom weavers in Karnataka state, India. 60.20% families are small families with 6 or fewer family members, of whom 25% have 3 members. 96.78% of small families have only one occupation. 30.50% of large families and 12.42% of medium sized families have more than one occupation. About 74% of families have income under the poverty line (under Rs 3500/year). 83% of small families are under the poverty line. The dependency ratio of small families is 1:2. 33% of all dependents are found among small families which are below the poverty line. 82% of dependents in small families are in small families under the poverty line. Almost 50% of dependents belong to small families. Small families are found to have slightly lower levels of education, although average level of education is very similar regardless of family size. The findings are used as evidence that small families do not necessarily augment the economy and that economic, educational, and cultural thresholds may be necessary before small family size affects economic development and improves the general well-being of family members. The social system that the small family is operating in is considered an important factor affecting the quality of life of the family.

Balancing act: the influence of adaptability and cohesion on satisfaction and communication in families facing TBI in Mexico.

PubMed

Lehan, Tara J; Stevens, Lillian Flores; Arango-Lasprilla, Juan Carlos; Díaz Sosa, Dulce María; Espinosa Jove, Irma Guadalupe

2012-01-01

Much of what is known about family functioning in the face of traumatic brain injury (TBI) is based on research conducted in the United States. The purpose of this study was to (1) describe the levels of family adaptability, cohesion, communication, and satisfaction as reported by Mexican TBI survivors and their family caregivers, (2) test the hypothesis of the Circumplex Model that balanced families would exhibit better communication and greater satisfaction, and (3) explore how TBI survivors' and their family caregivers' perceptions of family adaptability and cohesion influenced their own and the other's perceptions of family communication and satisfaction. In the majority of dyads, both the TBI survivor and the family caregiver endorsed balanced family adaptability and cohesion. Both TBI survivors and their family caregivers reported a relatively high level of family communication and satisfaction. TBI survivors and family caregivers who reported greater levels of family adaptability and cohesion also endorsed better family communication and greater family satisfaction. In addition, individuals with TBI whose family caregiver endorsed balanced family adaptability and cohesion reported better family communication. Further, family caregivers of TBI survivors who reported balanced family adaptability and cohesion reported better family communication. Implications for research and practice are discussed.

Factors of caregiver burden and family functioning among Taiwanese family caregivers living with schizophrenia.

PubMed

Hsiao, Chiu-Yueh; Tsai, Yun-Fang

2015-06-01

To assess the degree of caregiver burden and family functioning among Taiwanese primary family caregivers of people with schizophrenia and to test its association with demographic characteristics, family demands, sense of coherence and family hardiness. Family caregiving is a great concern in mental illness. Yet, the correlates of caregiver burden and family functioning in primary family caregivers of individuals with schizophrenia still remain unclear. A cross-sectional descriptive study. A convenience sample of 137 primary family caregivers was recruited from two psychiatric outpatient clinics in Taiwan. Measures included a demographic information sheet and the Chinese versions of the Family Stressors Index, Family Strains Index, 13-item Sense of Coherence Scale, 18-item Caregiver Burden Scale, Family Hardiness Index and Family Adaptability, Partnership, Growth, Affection, and Resolve Index. Data analysis included descriptive statistics, Pearson's product-moment correlation coefficients, t-test, one-way analysis of variance and a stepwise multiple linear regression. Female caregivers, additional dependent relatives, increased family demands and decreased sense of coherence significantly increased caregiver burden, whereas siblings as caregivers reported lower degrees of burden than parental caregivers. Family caregivers with lower family demands, increased family hardiness and higher educational level had significantly enhanced family functioning. Sense of coherence was significantly correlated with family hardiness. Our findings highlighted the importance of sense of coherence and family hardiness in individual and family adaptation. Special attention needs to focus on therapeutic interventions that enhance sense of coherence and family hardiness, thereby improving the perception of burden of care and family functioning. Given the nature of family caregiving in schizophrenia, understanding of correlates of caregiver burden and family functioning would help provide useful avenues for the development of family-focused intervention in psychiatric mental health nursing practice. © 2014 John Wiley & Sons Ltd.

Family functioning of child-rearing Japanese families on family-accompanied work assignments in Hong Kong.

PubMed

Hohashi, Naohiro; Honda, Junko

2011-11-01

Although the number of employees on overseas assignments accompanied by their families has increased steadily, little is known about the effects of this experience on family functioning. Japanese families on family-accompanied assignments living in Hong Kong were compared with families living in Japan (consisting of 135 and 248 paired partners, respectively). Applying an ecological framework, family functioning was examined using the Feetham Family Functioning Survey-Japanese (FFFS-J). Japanese wives living in Hong Kong rated family functioning lower, particularly in the area of "relationship between family and family members." Between paired marital partners living in Hong Kong, the level of satisfaction in the area of "relationship between family and society" was significantly lower for wives than for husbands. This study provides application of the family ecological framework in families in a multicultural environment and identifies potential areas for family assessment and intervention that may of interest to health care professionals who care for families living away from their home countries.

Using family paradigms to improve evidence-based practice.

PubMed

Hidecker, Mary Jo Cooley; Jones, Rebecca S; Imig, David R; Villarruel, Francisco A

2009-08-01

Evidence-based practice (EBP) describes clinical decision making using research, clinical experience, and client values. For family-centered practices, the client's family is integral to this process. This article proposes that using family paradigms, a family science framework, may help elicit and understand client/family values within family-centered EBP. This article describes the family paradigms framework: 4 classic paradigms of "closed," "random," "open," and "synchronous." Its applicability to family-centered EBP is proposed using augmentative and alternative communication examples. A family-centered approach to EBP requires families to be an integral part of clinical decision making, but some families may need assistance in enumerating their views and values. Family paradigms (which consider how a family uses its resources of time, space, energy, and material in the pursuit of its goals of control, affect, meaning, and content) may be a way to elicit family values and preferences relevant to clinical decisions. Family and client values can be incorporated throughout the EBP steps. Considering family paradigms may increase awareness and understanding of how families' views of their goals and resources affect clinical decisions. Further research is needed into both the processes and effectiveness of using family paradigms to conduct family-centered EBP.

Family Structure and Family Processes in Mexican American Families

PubMed Central

Zeiders, Katharine H.; Roosa, Mark W.; Tein, Jenn-Yun

2010-01-01

Despite increases in single-parent families among Mexican Americans (MA), few studies have examined the association of family structure and family adjustment. Utilizing a diverse sample of 738 Mexican American families (21.7% single parent), the current study examined differences across family structure on early adolescent outcomes, family functioning, and parent-child relationship variables. Results revealed that early adolescents in single parent families reported greater school misconduct, CD/ODD and MDD symptoms, and greater parent-child conflict than their counterparts in two parent families. Single parent mothers reported greater economic hardship, depression and family stress. Family stress and parent-child conflict emerged as significant mediators of the association between family structure and early adolescent outcomes, suggesting important processes linking MA single parent families and adolescent adjustment. PMID:21361925

Exploring families' experiences of health: contributions to a model of family health.

PubMed

Smith, Sarah L; DeGrace, Beth; Ciro, Carrie; Bax, Ami; Hambrick, Andrea; James, Jennifer; Evans, Alexandra

2017-12-01

Child health and developmental outcomes are influenced by the health of the family and the context created. Research suggests symptoms of poor family health (e.g. suboptimal family interactions, parenting stress) yet there is limited understanding of the factors which contribute to robust family health which may unveil opportunities for targeted intervention and family health promotion. The present study examined families' experiences of family health and factors contributing to family health. We performed a qualitative study using constructivist grounded theory methods to guide our understanding of family health for families with typically developing children aged 5-18. Interviews were conducted in family homes and all members were invited to participate. Data from interviews were transcribed, coded, thematically analyzed, and verified with select families. Ten families, including 10 mothers, 8 fathers, and 15 children participated in the study. Participants described family health as a process of balance, living purposefully, and sharing experiences together in alignment with family identity. Mediating family health were processes of awareness and reflection, and adapting, adjusting, and changing in response to family life including external stress factors. Results highlight the possibility for healthcare practitioners to facilitate families' self-reflection and awareness about their health in order to mediate family health development.

A Comparison Study of Single-Parent Families Living on Remote, Rural Islands and in Urban Settings in Japan.

PubMed

Hiratani, Yuko; Hohashi, Naohiro

2016-06-01

Nursing interventions that aim to enhance the family environment are necessary to help single-parent families with children to improve family functioning. The cultural and social factors that are unique to Japan's remote islands should be considered to assess the influence of this unique setting on family functioning. The objectives of this study were to evaluate the family functioning of child-rearing single-parent families living in different environments and to investigate the association between family demographics and family functioning. A self-administered questionnaire, the Japanese version of the Survey of Family Environment, was used to evaluate the sufficiency of family functioning. The participants were families with children enrolled in nurseries and kindergartens who were either living in remote, rural islands or in an urban city on the mainland in Japan. Family functioning was significantly higher for single-parent families living on the islands than for those living in the city in terms of media use, participation in community activities, and the collaboration of family members in child-rearing. Family functioning of single-parent families correlated significantly with household income, the parent's gender, family members' health, and family life cycle. Single-parent families living on Japanese offshore islands maintained family functioning through mutual support and the effective use of information technology. Nevertheless, single-parent families require additional support to improve their healthcare and financial situations.

National Foster Care and Adoption Directory Search

MedlinePlus

... Home Topics Family-Centered Practice Philosophy and Key Elements of Family-Centered Practice Family-Centered Practice Across the Service Continuum Engaging Families Family-Centered Casework Practice Family Group Decision-Making Engaging Communities to Support Families Creating a Family- ...

A systematic review of the literature on family functioning across all eating disorder diagnoses in comparison to control families.

PubMed

Holtom-Viesel, Anita; Allan, Steven

2014-02-01

The objectives of this review were to systematically identify and evaluate quantitative research comparing family functioning (a) in eating disorder families with control families, (b) in families with different eating disorder diagnoses (c) perceptions of different family members and (d) the relationship between family functioning and recovery. This adds to the findings of previous reviews of family functioning by including data from control families, the range of diagnoses, and focusing on recovery. Findings were considered in relation to models of family functioning. Using specific search criteria, 17 research papers were identified and evaluated. Findings indicated that eating disorder families reported worse family functioning than control families but there was little evidence for a typical pattern of family dysfunction. A consistent pattern of family dysfunction for different diagnoses was not suggested but patients consistently rated their family as more dysfunctional than one or both of their parents. With respect to outcome and recovery, those with more positive perceptions of family functioning generally had more positive outcomes, irrespective of severity of eating disorder. Conclusions were limited by inconsistent findings and methodological issues. Further research is needed into the relationship between family functioning and outcome and the assessment of family functioning beyond self-report. © 2013.

Family functioning in the families of psychiatric patients: a comparison with nonclinical families.

PubMed

Trangkasombat, Umaporn

2006-11-01

To examine family functioning in the families of psychiatric patients. Families of psychiatric patients and nonclinical families were compared. There were 60 families in each group. The instrument included a semistructured interview of family functioning and the Chulalongkorn Family Inventory (CFI), a self-report questionnaire designed to assess the perception of one's family. From the assessment by semistructured interview, 83.3% of psychiatric families and 45.0% of nonclinical families were found to be dysfunctional in at least one dimension. The difference was statistically significant (p < 0.001). The average number of dysfunctional dimensions in the psychiatric families was significantly higher than in the nonclinical control group, 3.5 +/- 1.9 and 0.98 +/- 1.5 respectively, p < 0.0001. The CFI scores of the psychiatric families were significantly lower than the control group, reflecting poor family functioning. The dysfunctions were mostly in the following dimensions: problem-solving, communication, affective responsiveness, affective involvement, and behavior control. Psychiatric families faced more psychosocial stressors and the average number of stressors was higher than the control families, 88.3% vs. 56.7% and 4.2 +/- 2.7 vs. 1.3 +/- 1.47 stressors respectively, p < 0.0001. Family functioning of psychiatric patients was less healthy than the nonclinical control. The present study underlined the significance of family assessment and family intervention in the comprehensive care of psychiatric patients.

Who counts as family? Family typologies, family support, and family undermining among young adult gay and bisexual men.

PubMed

Soler, Jorge H; Caldwell, Cleopatra H; Córdova, David; Harper, Gary; Bauermeister, José A

2018-06-01

Gay and bisexual men may form chosen families in addition to or in place of families of origin. However, the characteristics of these diverse families remain largely unexamined in the quantitative literature. The purpose of this study was to develop a family typology based on responses from a racially and ethnically diverse sample of young adult gay and bisexual men (YGBM) recruited from the Detroit Metropolitan Area (N=350; 18-29 years old). To explore the role of family, we then examined family social support and social undermining in relation to YGBM psychological distress within different family types. A series of multivariate regressions were used to examine associations between family social support and social undermining with depression and anxiety outcomes. The majority (88%) of YGBM included family of origin in their definitions of family and 63% indicated having chosen families. Associations between family social processes and psychological outcomes varied by type of family, suggesting that family composition shapes how perceptions of support and undermining relate to experiencing symptoms of depression and anxiety. Chosen families play a prominent role in the lives of YGBM and should not be overlooked in family research. Findings also highlight the importance of examining co-occurring family social support and social stress processes to further address psychological distress symptoms among YGBM.

Strengthening Families: Exploring the Impacts of Family Camp Experiences on Family Functioning and Parenting

ERIC Educational Resources Information Center

Garst, Barry A.; Baughman, Sarah; Franz, Nancy K.; Seidel, Richard W.

2013-01-01

Research suggests that family camp experiences can enhance family relationships. Families often participate in family camp experiences for a vacation, as part of a therapeutic and/or intervention strategy, or to gain general enrichment or engagement. To better understand the impacts of family camp experiences on family functioning, a mixed-methods…

Family Issues for the Nineties.

ERIC Educational Resources Information Center

Mirabelli, Alan

This presentation reviews the characteristics of the Canadian family at present. Discussion focuses on divorce, family structure, reproductive technology, fertility, family size, family mobility, family support, government role, women's participation in the labor force, daily family routines, television viewing, work and the family, the need for…

The effect of families on the process of outpatient visits in family practice.

PubMed

Main, D S; Holcomb, S; Dickinson, P; Crabtree, B F

2001-10-01

Our goal was to describe how physician knowledge of patients' families affects the processes of patient care in family practices. Using a multimethod comparative case study design, detailed dictated field notes were recorded after direct observation of patient encounters and the office environment as part of the Prevention and Competing Demands in Primary Care Study. We identified domains of outpatient visits in which patients were accompanied by a family member or in which family-oriented content was discussed. Outpatient encounters with 1637 patients presenting in 18 family practices in the Midwest were analyzed using an editing style. We developed a typology for ways in which family context affects outpatient visits. Patients were accompanied during 35% of all outpatient visits, the vast majority of these visits involving children. Family history or a family member's problems were discussed during 35% of visits during which no family member was present. An analysis of these "family-oriented" visits resulted in a typology of 6 ways that family context informs and affects the outpatient visit: (1) using family social context to illuminate patient disease, illness, and health; (2) using family to discover the source of an illness; (3) discussing and managing the health and illness of family members; (4) family concern for patient's health; (5) using the family as a care resource and care collaborator; and, (6) giving family members unscheduled care. Family context is an important feature of family practice that influences the processes of patient care. Since family-oriented care is an essential feature of family practice, outcomes of this largely hidden part of care deserve further study.

Small Families

MedlinePlus

... Life Family Life Family Life Medical Home Family Dynamics Media Work & Play Getting Involved in Your Community ... Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care Communication & Discipline Types of Families ...

Family ties and economic stability concerns of migrant labour families in Jordan.

PubMed

Kamiar, M S; Ismail, H F

1991-12-01

74 labor migrant families from various socioeconomic classes in Amman, Jordan were interviewed to examine changes in relationships among family members, extended family, and neighbors and their concerns about economic stability in the host country, Jordan, and the world market. Another purpose was to determine how current migration policies of the Arab oil-producing countries which prohibit labor migrants from bringing their families to the host country affect labor migration among families. The families consisted of either those who did or did not accompany the labor migrant. Overall labor migration affected unaccompanied families more than accompanied families, e.g., only 19% of the unaccompanied families reported increased family unity compared with 56% of accompanied families. Problems within unaccompanied families increased in 43% of the cases but in only 6% of the accompanied families. Many of these problems resulted in children dropping out of school which reflected the control fathers had within the family, separation, or divorce. Yet labor migration reduced family ties with extended family members and neighbors almost equally for both groups. Accompanied families were not as concerned about economic stability in Jordan as unaccompanied families (38% vs. 50%). Perhaps these families tended not to invest remittances received from the labor migrants working in Arab oil-producing countries in Jordan. Both groups were quite concerned about the economic stability in the host countries (66% and 72%, respectively) and the world market (59% and 62%, respectively), however. Since family unity suffers when families do not accompany labor migrants, it is suggested that oil-producing nations that depend on foreign labor should guarantee family unity as a human right.

Family First? The Costs and Benefits of Family Centrality for Adolescents with High-Conflict Families.

PubMed

Yuen, Cynthia X; Fuligni, Andrew J; Gonzales, Nancy; Telzer, Eva H

2018-02-01

Youth who do not identify with or value their families (i.e., low family centrality) are considered to be at risk for maladjustment. However, the current study investigated whether low family centrality may be adaptive in negative family contexts (i.e., high family conflict) because youth's self-worth should be less tied to the quality of their family relationships. Multilevel models using daily diaries and latent variable interactions using longitudinal questionnaires indicated that, among a sample of 428 Mexican American adolescents (49.8% male, M age  = 15.02 years), lower family centrality was generally detrimental to youth's well-being. However, for youth in adverse family environments, low family centrality ceased to function as a risk factor. The present findings suggest that family centrality values play a more nuanced role in youth well-being than previously believed, such that low family centrality may be an adaptive response to significant family challenges.

Normal Functioning Family

MedlinePlus

... Life Family Life Family Life Medical Home Family Dynamics Media Work & Play Getting Involved in Your Community ... Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care Communication & Discipline Types of Families ...

Family resources study: part 1: family resources, family function and caregiver strain in childhood cancer.

PubMed

Panganiban-Corales, Avegeille T; Medina, Manuel F

2011-10-31

Severe illness can disrupt family life, cause family dysfunction, strain resources, and cause caregiver burden. The family's ability to cope with crises depends on their resources. This study sought to assess families of children with cancer in terms of family function-dysfunction, family caregiver strain and the adequacy of family resources using a new family resources assessment instrument. This is a cross-sectional study involving 90 Filipino family caregivers of children undergoing cancer treatment. This used a self-administered questionnaire composed of a new 12-item family resources questionnaire (SCREEM-RES) based on the SCREEM method of analysis, Family APGAR to assess family function-dysfunction; and Modified Caregiver Strain Index to assess strain in caring for the patient. More than half of families were either moderately or severely dysfunctional. Close to half of caregivers were either predisposed to strain or experienced severe strain, majority disclosed that their families have inadequate economic resources; many also report inaccessibility to medical help in the community and insufficient educational resources to understand and care for their patients. Resources most often reported as adequate were: family's faith and religion; help from within the family and from health providers. SCREEM-RES showed to be reliable with Cronbach's alpha of 0.80. There is good inter-item correlation between items in each domain: 0.24-0.70. Internal consistency reliability for each domain was also good: 0.40-0.92. Using 2-point scoring system, Cronbach's alpha were slightly lower: full scale (0.70) and for each domain 0.26-.82. Results showed evidence of association between family resources and family function based on the family APGAR but none between family resources and caregiver strain and between family function and caregiver strain. Many Filipino families of children with cancer have inadequate resources, especially economic; and are moderately or severely dysfunctional. Many caregivers are predisposed to caregiver strain or are already experiencing severe strain. To provide appropriate care for these families, physicians should regularly assess family function, resources and strain experienced by caregivers. The SCREEM-RES questionnaire used in this study is a helpful and reliable instrument to assess adequacy of family resources.

Too close and too rigid: applying the Circumplex Model of Family Systems to first-generation family firms.

PubMed

Michael-Tsabari, Nava; Lavee, Yoav

2012-06-01

Despite growing research interest in family businesses, little is known about the characteristics of the families engaging in them. The present paper uses Olson's (Journal of Psychotherapy & the Family, 1988, 4(12), 7-49; Journal of Family Therapy, 2000, 22, 144-167) Circumplex Model of Marital and Family Systems to look at first-generation family firms. We describe existing typologies of family businesses and discuss similarities between the characteristics of first-generation family firms and the rigidly enmeshed family type described in the Circumplex Model. The Steinberg family business (Gibbon & Hadekel (1990) Steinberg: The breakup of a family empire. ON, Canada: MacMillan) serves to illustrate the difficulties of rigidly enmeshed first-generation family firms. Implications for understanding troubled family businesses are discussed together with guidelines for the assessment of a family business in crisis and for intervention: enhancing open communication; allowing for more flexible leadership style, roles, and rules; and maintaining a balance between togetherness and separateness. © 2012 American Association for Marriage and Family Therapy.

A model of adaptation for families of elderly patients with dementia: focusing on family resilience.

PubMed

Kim, Geun Myun; Lim, Ji Young; Kim, Eun Joo; Kim, Sang Suk

2017-07-19

We constructed a model explaining families' positive adaptation in chronic crisis situations such as the problematic behavior of elderly patients with dementia and attendant caregiving stress, based on the family resilience model. Our aim was to devise an adaptation model for families of elderly patients with dementia. A survey of problematic behavior in elderly patients with dementia, family stress, family resilience, and family adaptation was conducted with 292 consenting individuals. The collected data were analyzed using structural equation modeling. The communication process, family stress, and problematic behavior of elderly patients with dementia had direct and indirect effects on family adaptation, while belief system, organization pattern, and social support had indirect effects. Specifically, family stress and more severe problematic behavior by elderly patients with dementia negatively influenced family adaptation, while greater family resilience improved such adaptation. Interventions aiming to enhance family resilience, based on the results of this study, are required to help families with positive adaptation. Such family programs might involve practical support such as education on the characteristics of elderly persons with dementia and coping methods for their problematic behavior; forming self-help groups for families; revitalizing communication within families; and activating communication channels with experts.

Family members' unique perspectives of the family: examining their scope, size, and relations to individual adjustment.

PubMed

Jager, Justin; Bornstein, Marc H; Putnick, Diane L; Hendricks, Charlene

2012-06-01

Using the McMaster Family Assessment Device (Epstein, Baldwin, & Bishop, 1983) and incorporating the perspectives of adolescent, mother, and father, this study examined each family member's "unique perspective" or nonshared, idiosyncratic view of the family. We used a modified multitrait-multimethod confirmatory factor analysis that (a) isolated for each family member's 6 reports of family dysfunction the nonshared variance (a combination of variance idiosyncratic to the individual and measurement error) from variance shared by 1 or more family members and (b) extracted common variance across each family member's set of nonshared variances. The sample included 128 families from a U.S. East Coast metropolitan area. Each family member's unique perspective generalized across his or her different reports of family dysfunction and accounted for a sizable proportion of his or her own variance in reports of family dysfunction. In addition, after holding level of dysfunction constant across families and controlling for a family's shared variance (agreement regarding family dysfunction), each family member's unique perspective was associated with his or her own adjustment. Future applications and competing alternatives for what these "unique perspectives" reflect about the family are discussed. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Family Members' Unique Perspectives of the Family: Examining their Scope, Size, and Relations to Individual Adjustment

PubMed Central

Jager, Justin; Bornstein, Marc H.; Diane, L. Putnick; Hendricks, Charlene

2012-01-01

Using the Family Assessment Device (FAD; Epstein, Baldwin, & Bishop, 1983) and incorporating the perspectives of adolescent, mother, and father, this study examined each family member's “unique perspective” or non-shared, idiosyncratic view of the family. To do so we used a modified multitrait-multimethod confirmatory factor analysis that (1) isolated for each family member's six reports of family dysfunction the non-shared variance (a combination of variance idiosyncratic to the individual and measurement error) from variance shared by one or more family members and (2) extracted common variance across each family member's set of non-shared variances. The sample included 128 families from a U.S. East Coast metropolitan area. Each family member's unique perspective generalized across his or her different reports of family dysfunction and accounted for a sizable proportion of his or her own variance in reports of family dysfunction. Additionally, after holding level of dysfunction constant across families and controlling for a family's shared variance (agreement regarding family dysfunction), each family member's unique perspective was associated with his or her own adjustment. Future applications and competing alternatives for what these “unique perspectives” reflect about the family are discussed. PMID:22545933

Myth of the Perfect Family

MedlinePlus

... Life Family Life Family Life Medical Home Family Dynamics Media Work & Play Getting Involved in Your Community ... Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care Communication & Discipline Types of Families ...

Family Health History and Diabetes

MedlinePlus

... Risk Test Family Health History Quiz Family Health History Quiz Family health history is an important risk ... Should Ask Your Family About Diabetes & Family Health History Knowing your family health history is important. Here ...

Family Efficacy within Ethnically Diverse Families: A Qualitative Study.

PubMed

Kao, Tsui-Sui A; Caldwell, Cleopatra H

2017-03-01

Family efficacy, which refers to a family's belief in its ability to produce a desired outcome, has been shown to protect adolescents from risky health behaviors. Few studies have examined family efficacy within diverse populations, however, and understanding of how efficacy is framed and formed within the context of cultural and familial values is limited. This descriptive qualitative study examined sources of family efficacy within ethnically and socioeconomically diverse families, evaluating how such families develop and exercise family efficacy with the intent to protect adolescents from risky health behaviors (i.e., marijuana and alcohol use and early sexual activity). We collected qualitative data via two semi-structured interviews, 4-6 months apart, with 31 adolescents (ages 12-14) and their parent/s, for total of 148 one-on-one interviews. Thematic analysis identified three distinct domains of family efficacy: relational, pragmatic, and value-laden. Prior experiences and cultural background influenced the domain/s utilized by families. Significantly, families that consistently tapped into all three domains were able to effectively manage personal and family difficulties; these families also had family strategies in place to prevent adolescents from risky behaviors. Health professionals could utilize this concept of multidimensional family efficacy to promote health within culturally diverse families. © 2015 Family Process Institute.

The context of collecting family health history: examining definitions of family and family communication about health among African American women.

PubMed

Thompson, Tess; Seo, Joann; Griffith, Julia; Baxter, Melanie; James, Aimee; Kaphingst, Kimberly A

2015-04-01

Public health initiatives encourage the public to discuss and record family health history information, which can inform prevention and screening for a variety of conditions. Most research on family health history discussion and collection, however, has predominantly involved White participants and has not considered lay definitions of family or family communication patterns about health. This qualitative study of 32 African American women-16 with a history of cancer-analyzed participants' definitions of family, family communication about health, and collection of family health history information. Family was defined by biological relatedness, social ties, interactions, and proximity. Several participants noted using different definitions of family for different purposes (e.g., biomedical vs. social). Health discussions took place between and within generations and were influenced by structural relationships (e.g., sister) and characteristics of family members (e.g., trustworthiness). Participants described managing tensions between sharing health information and protecting privacy, especially related to generational differences in sharing information, fear of familial conflict or gossip, and denial (sometimes described as refusal to "own" or "claim" a disease). Few participants reported that anyone in their family kept formal family health history records. Results suggest family health history initiatives should address family tensions and communication patterns that affect discussion and collection of family health history information.

Impact of chronic obstructive pulmonary disease on family functioning.

PubMed

Kanervisto, Merja; Paavilainen, Eija; Astedt-Kurki, Päivi

2003-01-01

The purpose of this study was to ascertain family dynamics of Finnish patients with severe chronic obstructive pulmonary disease (COPD) on the basis of Barnhill's framework for healthy family functioning. This study used description and comparison and an interview-administered questionnaire and survey. Participants were patients with COPD and their family members (n = 65) living in the Tampere University Hospital catchment area. The sample consisted of families of home oxygen therapy patients (n = 36) and families of inpatients (n = 29). Families consisted of patients and their family members. Data were collected from patients by interview-administered questionnaires and from family members by survey. The instrument used was the Family Dynamics Measure 2, operationalized and tested by the American Family Research Group. Families of home oxygen therapy patients experienced significantly more mutuality (P =.03) and made decisions about their illness and life significantly more independently (P =.05) than families of inpatients. Families of home oxygen therapy patients handled change significantly more flexibly (P =.03) than families of inpatients. For the most part, families of both patient groups functioned well, but overall family functioning was clearly better in families of home oxygen therapy patients. The sample included some dysfunctional and even severely dysfunctional families. The results of this study cannot be generalized beyond the study sample because of the small sample size, but they provide suggestions for developing the care of patients with COPD and their families.

The impact of changes in China's family patterns on family pension functions.

PubMed

Su, Zhongxin; Hu, Z; Peng, Xizhe

2017-07-01

Using data from the Chinese census and the China Statistical Yearbook, this paper will analyze the historical changes and future trends of family households in China over the past 30 years and explore the changes of family pension functions and corresponding policies. Our analysis yielded 3 notable results. First, in family size miniaturization and structural simplification, 1- and 2-generation family households are the main body of contemporary China. Second, for family aging and changes in living patterns, which primarily manifest as an increase in; the proportion of elderly households and in middle-aged and elderly people in the family, the elderly model and the "multigenerational model" have become the 2 major residence models for the elderly in China. Third, nontraditional families have emerged in large numbers, such as the exclusively elderly family, empty nest family, grandparents family, Double Income, No Kids (DINK) family, older single family, and single-parent family. We argue that in the process of simplification, China's family structure is increasingly showing characteristics of networking. The change in family patterns entails the restoration of traditional functions and taking on new functions of the family by issuing relevant social policies. Only when these social policies are based on family functions and demands can they provide effective help to social members, particularly regarding the family's responsibilities to parent children and support the elderly. Copyright © 2017 John Wiley & Sons, Ltd.

Resilience in families in which a member has been diagnosed with schizophrenia.

PubMed

Bishop, M; Greeff, A P

2015-09-01

Due to the extensive focus of the literature on the burden placed on families in which a member has been diagnosed with a mental illness such as schizophrenia, there is a need to identify factors that may help these families to be resilient and adapt to their crisis. The aim of this study was to identify family resilience qualities in families in which a member has been diagnosed with schizophrenia. The study comprised 42 families, represented by 33 parents and 9 siblings of the diagnosed family member. Families were recruited from three support groups within the Cape Metropolitan area, Western Cape, South Africa. Qualitative data were obtained through an open-ended question and quantitative data were collected with seven self-report questionnaires. The following family resilience qualities were identified: family income; finding support in their community; family togetherness; family communication style during crises; affirming and supportive communication patterns; family hardiness; commitment to the family; reframing crises as a challenge; and an internal locus of control within the family. The findings may be used by professionals and support group facilitators to enhance the resilience and functioning of families living with a member with schizophrenia. With approximately 1% of the world's population diagnosed with schizophrenia, it is clear that many families are affected when a member has been diagnosed. There is a need to identify factors that may help these families to be resilient. The aim of this study was to identify family resilience qualities in families in which a member has been diagnosed with schizophrenia. The following family resilience qualities were identified as resources that helped them to adapt to the many challenges put to them: family income, finding support in their community, the availability of hospitals, churches and professionals, family togetherness, family communication, family hardiness, commitment to the family, reframing crises as a challenge, and an internal locus of control within the family. Due to the limited studies on resilience in families in which a member has been diagnosed with schizophrenia, we suggest that the current study may contribute to this literature and provide a more comprehensive look at resilience in these families. Furthermore, the current study may contribute to knowledge about factors and resources that are associated with resilience in families in which a member has been diagnosed with schizophrenia. Finally, the findings of this study may be used in interventions to help families from different cultures and socio-economic statuses to adapt and hence be resilient. © 2015 John Wiley & Sons Ltd.

A perfect fit: connecting family therapy skills to family business needs.

PubMed

Cole, Patricia M; Johnson, Kit

2012-06-01

The purpose of this article is to encourage family therapists to become more interested in family business practice. It does so in three ways: (a) highlighting the number of therapists already involved in family business issues; (b) showing the parallels between family business and family therapy by applying family business research findings to couples therapy; (c) discussing how family therapists already have the practice wisdom to be effective in working with family business clients. Limitations of this practice are also discussed along with suggestions for overcoming them. © 2012 American Association for Marriage and Family Therapy.

Spiritual Coping: A Gateway to Enhancing Family Communication During Cancer Treatment.

PubMed

Prouty, Anne M; Fischer, Judith; Purdom, Ann; Cobos, Everardo; Helmeke, Karen B

2016-02-01

The researchers examined the spiritual coping, family communication, and family functioning of 95 participants in 34 families by an online survey. Multilevel linear regression was used to test whether individuals' and families' higher endorsement of more use of spiritual coping strategies to deal with a member's cancer would be associated with higher scores on family communication and family functioning, and whether better communication would also be associated with higher family functioning scores. Results revealed that spiritual coping was positively associated with family communication, and family communication was positively associated with healthier family functioning. The researchers provide suggestions for further research.

A family beliefs framework for socially and culturally specific preventive interventions with refugee youths and families.

PubMed

Weine, Stevan; Feetham, Suzanne; Kulauzovic, Yasmina; Knafl, Kathleen; Besic, Sanela; Klebic, Alma; Mujagic, Aida; Muzurovic, Jasmina; Spahovic, Dzemila; Pavkovic, Ivan

2006-01-01

To assist in designing socially and culturally specific preventive interventions for refugee youths and families, this study identified the processes by which refugee families adapt and apply family beliefs concerning youths. A grounded-theory model constructed with ATLAS/ti for Windows and named the family beliefs framework describes (a) family beliefs concerning refugee youths, (b) contextual factors interacting with these family beliefs, (c) adaptation of family beliefs concerning refugee youths, and (d) the interplay of adapting family beliefs and behaviors concerning refugee youths. Preventive interventions for refugee youths and families would be more socially and culturally specific if they addressed the specific processes of adapting family beliefs experienced by refugee youths and their families amid transitions and traumas. 2006 APA, all rights reserved

Family influence on volunteering intention and behavior among Chinese adolescents in Hong Kong.

PubMed

Law, Ben M F; Shek, Daniel T L

2009-01-01

Based on the responses of 5,946 adolescents (mean age = 14.77), the relationships among family influence, adolescents' volunteering intention, and volunteering behavior in a Chinese context were examined. A 9-item Chinese Family Influence on Adolescent Volunteerism Scale (C-FIAV) was used to measure nine kinds of influence of the family (such as family support) which could be subsumed under two underlying domains (positive family influence and extrinsic family influence). Results showed that family support, family belief, and family modeling were positively associated with both intention and behavior. Family reward and coercion were negatively associated with both intention and behavior. Family belief in volunteerism was the most critical factor. Grade and gender differences were found only in the associations between family influence and volunteering intention. Path models showed that positive and extrinsic family influence had an effect on volunteering behavior directly or via the mediation of volunteering intention. Implications and limitations are discussed.

Parents' Romantic Attachment Predicts Family Ritual Meaning and Family Cohesion Among Parents and Their Children With Cancer.

PubMed

Santos, Susana; Crespo, Carla; Canavarro, M Cristina; Kazak, Anne E

2017-01-01

Family functioning is associated with adaptation in pediatric illness. This study examines the role of parents’ relationships (specifically romantic attachment) as a predictor of family ritual meaning and family cohesion for parents and their children with cancer. The dyads, 58 partnered Portuguese parents and their children in treatment, reported on family ritual meaning and family cohesion at Time 1 (T1) and after 6 months (T2). Parents also completed the questionnaire assessing romantic attachment at T1. Parents’ avoidant attachment, but not anxious attachment, predicted lower family ritual meaning and family cohesion after 6 months. T2 family ritual meaning mediated the relationship between T1 avoidant attachment and T2 family cohesion. Parents’ avoidant attachment may have a negative effect on family functioning in parents and children. Clinical intervention to address avoidant attachment or/and to promote family ritual meaning may help strengthen family ties.

[Different approaches to the family in the context of the family health program/strategy].

PubMed

Ribeiro, Edilza Maria

2004-01-01

This study presents the scenario that favored the inclusion of the family as a care focus in public policies. The strategies to interrupt the impoverishment and vulnerability of families in the XXth century occur in a different form, according to different "welfare states" in capitalist societies. However, in view of the welfare state crisis and the increasing costs of public and private services and privates, at least a partial family solution is required in terms of reducing its dependency. The Family Health Program (PSF) put the family on the Brazilian social policy agenda in 1994, reflecting interests from the neoliberal model as well as from solidary social forces. This inclusion generated different approaches, such as: family/individual; family/home; family/individual/home; family/community; family/social risk; family/family. These approaches, due to the lack of a mutual dialogue, end up composing an insufficiently identified picture, thus turning care more difficult. The conditions indicated here should be examined as a way of giving a true chance to the family

Development and Examination of a Family Triadic Measure to Examine Quality of Life Family Congruence in Nursing Home Residents and Two Family Members.

PubMed

Aalgaard Kelly, Gina

2015-01-01

Objective: The overall purpose of this study was to propose and test a conceptual model and apply family analyses methods to understand quality of life family congruence in the nursing home setting. Method: Secondary data for this study were from a larger study, titled Measurement, Indicators and Improvement of the Quality of Life (QOL) in Nursing Homes . Research literature, family systems theory and human ecological assumptions, fostered the conceptual model empirically testing quality of life family congruence. Results: The study results supported a model examining nursing home residents and two family members on quality of life family congruence. Specifically, family intergenerational dynamic factors, resident personal and social-psychological factors, and nursing home family input factors were examined to identify differences in quality of life family congruence among triad families. Discussion: Formal family involvement and resident cognitive functioning were found as the two most influential factors to quality of life family congruence (QOLFC).

Development and Examination of a Family Triadic Measure to Examine Quality of Life Family Congruence in Nursing Home Residents and Two Family Members

PubMed Central

Aalgaard Kelly, Gina

2015-01-01

Objective: The overall purpose of this study was to propose and test a conceptual model and apply family analyses methods to understand quality of life family congruence in the nursing home setting. Method: Secondary data for this study were from a larger study, titled Measurement, Indicators and Improvement of the Quality of Life (QOL) in Nursing Homes. Research literature, family systems theory and human ecological assumptions, fostered the conceptual model empirically testing quality of life family congruence. Results: The study results supported a model examining nursing home residents and two family members on quality of life family congruence. Specifically, family intergenerational dynamic factors, resident personal and social-psychological factors, and nursing home family input factors were examined to identify differences in quality of life family congruence among triad families. Discussion: Formal family involvement and resident cognitive functioning were found as the two most influential factors to quality of life family congruence (QOLFC). PMID:28138474

24 CFR 982.515 - Family share: Family responsibility.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Family share: Family responsibility... Assistance Payment § 982.515 Family share: Family responsibility. (a) The family share is calculated by subtracting the amount of the housing assistance payment from the gross rent. (b) The family rent to owner is...

24 CFR 982.515 - Family share: Family responsibility.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Family share: Family responsibility... Assistance Payment § 982.515 Family share: Family responsibility. (a) The family share is calculated by subtracting the amount of the housing assistance payment from the gross rent. (b) The family rent to owner is...

Family boundary characteristics, work-family conflict and life satisfaction: A moderated mediation model.

PubMed

Qiu, Lin; Fan, Jinyan

2015-10-01

Although work-family border and boundary theory suggest individuals' boundary characteristics influence their work-family relationship, it is largely unknown how boundary flexibility and permeability mutually influence work-family conflict and subsequent employee outcomes. Moreover, the existing work-family conflict research has been mainly conducted in the United States and other Western countries. To address these gaps in the work-family literature, the present study examines a moderated mediation model regarding how family boundary characteristics may influence individuals' work-family conflict and life satisfaction with a sample of 278 Chinese full-time employees. Results showed that employees' family flexibility negatively related to their perceived work interference with family (WIF) and family interference with work (FIW), and both these two relationships were augmented by individuals' family permeability. In addition, WIF mediated the relationship between family flexibility and life satisfaction; the indirect effect of family flexibility on life satisfaction via WIF was stronger for individuals with higher family permeability. The theoretical and managerial implications of these findings are discussed. © 2014 International Union of Psychological Science.

Family interactions in adoptive compared to nonadoptive families.

PubMed

Rueter, Martha A; Keyes, Margaret A; Iacono, William G; McGue, Matt

2009-02-01

Despite the large and growing numbers of adoptive families, little research describes interactions in families with adopted adolescents. Yet, adopted adolescents' increased risk for adjustment problems, combined with the association between family interactions and adolescent adjustment in nonadoptive families, raises questions about differences in adoptive and nonadoptive family interactions. We compared observed and self-reported family interactions between 284 adoptive and 208 nonadoptive families and within 123 families with 1 adopted and 1 nonadopted adolescent. Adolescents averaged 14.9 years of age. Comparisons were made using analysis of variance incorporating hierarchical linear methods in SAS PROC MIXED to control family-related correlations in the data. Parents and children reported more conflict in adoptive families when compared with nonadoptive families. Families with 1 adopted and 1 nonadopted adolescent reported more conflict between parents and adopted adolescents. Observed parental behavior was similar across adoptive and nonadoptive children although adopted adolescents were less warm and, in families with 2 adopted children, more conflictual than nonadopted adolescents. These findings suggest a need for further investigation of the association between family interactions and adopted adolescent problem behavior. Copyright 2009 APA, all rights reserved.

Family Interactions in Adoptive Compared to Nonadoptive Families

PubMed Central

Rueter, Martha A.; Keyes, Margaret A.; Iacono, William G.; McGue, Matt

2009-01-01

Despite the large and growing numbers of adoptive families, little research describes interactions in families with adopted adolescents. Yet, adopted adolescents’ increased risk for adjustment problems, combined with the association between family interactions and adolescent adjustment in nonadoptive families, raises questions about differences in adoptive and nonadoptive family interactions. We compared observed and self-reported family interactions between 284 adoptive and 208 nonadoptive families and within 123 families with 1 adopted and 1 nonadopted adolescent. Adolescents averaged 14.9 years of age. Comparisons were made using analysis of variance incorporating hierarchical linear methods in SAS PROC MIXED to control family-related correlations in the data. Parents and children reported more conflict in adoptive families when compared with nonadoptive families. Families with 1 adopted and 1 nonadopted adolescent reported more conflict between parents and adopted adolescents. Observed parental behavior was similar across adoptive and nonadoptive children although adopted adolescents were less warm and, in families with 2 adopted children, more conflictual than nonadopted adolescents. These findings suggest a need for further investigation of the association between family interactions and adopted adolescent problem behavior. PMID:19203160

Family involvement in cancer treatment decision-making: A qualitative study of patient, family, and clinician attitudes and experiences.

PubMed

Laidsaar-Powell, Rebekah; Butow, Phyllis; Bu, Stella; Charles, Cathy; Gafni, Amiram; Fisher, Alana; Juraskova, Ilona

2016-07-01

Little is known about how family are involved in cancer treatment decision-making. This study aimed to qualitatively explore Australian oncology clinicians', patients', and family members' attitudes towards, and experiences of, family involvement in decision-making. Semi-structured interviews were conducted with 30 cancer patients, 33 family members, 10 oncology nurses and 11 oncologists. Framework analysis methods were used. Three main themes were uncovered: (i) how family are involved in the decision-making process: specific behaviours of family across 5 (extended) decision-making stages; (ii) attitudes towards family involvement in the decision-making process: balancing patient authority with the rights of the family; and (iii) factors influencing family involvement: patient, family, cultural, relationship, and decision. This study highlighted many specific behaviours of family throughout the decision-making process, the complex participant attitudes toward retaining patient authority whilst including the family, and insight into influencing factors. These findings will inform a conceptual framework describing family involvement in decision-making. Clinicians could ascertain participant preferences and remain open to the varying forms of family involvement in decision-making. Given the important role of family in the decision-making process, family inclusive consultation strategies are needed. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Towards a model of resilience for transnational families of Filipina domestic workers

PubMed Central

Garabiles, Melissa R.; Ofreneo, Mira Alexis P.

2017-01-01

Many Filipinos experience poverty and poor employment opportunities. In order to alleviate poverty and provide sufficient resources for their families, numerous mothers leave the Philippines to become domestic workers. The present study aimed to build a model of family resilience for transnational families. A total of 33 participants consisting of Filipino transnational families, domestic workers, and key informants participated in a series of focus group discussions and interviews. A new model of resilience among transnational families of Filipina domestic helpers was created using a constructivist grounded theory approach. The model highlighted how temporal and spatial elements are embedded in collective migration experiences. Family narratives begin with the sacrifice of separation, where mothers leave their families for a chance to solve economic problems. To successfully adapt to their separation, the families undergo five relational processes. First, families communicate across space using technology to bridge relational distance. Second, families restructure across space through role sharing and the validation of each other’s efforts in their family roles. Third, families rebuild ties through temporary family reunification that bridge physical and relational distance. Fourth, families have the collective goal of permanent family reunification by ending migration to become complete again. Fifth, they strive to commit to their families by prioritizing them instead of succumbing to difficulties. Family resilience for transnational migrants is a collectivistic process, negotiated by each family member. PMID:28837633

Where are family theories in family-based obesity treatment?: conceptualizing the study of families in pediatric weight management

PubMed Central

Skelton, JA; Buehler, C; Irby, MB; Grzywacz, JG

2014-01-01

Family-based approaches to pediatric obesity treatment are considered the ‘gold-standard,’ and are recommended for facilitating behavior change to improve child weight status and health. If family-based approaches are to be truly rooted in the family, clinicians and researchers must consider family process and function in designing effective interventions. To bring a better understanding of family complexities to family-based treatment, two relevant reviews were conducted and are presented: (1) a review of prominent and established theories of the family that may provide a more comprehensive and in-depth approach for addressing pediatric obesity; and (2) a systematic review of the literature to identify the use of prominent family theories in pediatric obesity research, which found little use of theories in intervention studies. Overlapping concepts across theories include: families are a system, with interdependence of units; the idea that families are goal-directed and seek balance; and the physical and social environment imposes demands on families. Family-focused theories provide valuable insight into the complexities of families. Increased use of these theories in both research and practice may identify key leverage points in family process and function to prevent the development of or more effectively treat obesity. The field of family studies provides an innovative approach to the difficult problem of pediatric obesity, building on the long-established approach of family-based treatment. PMID:22531090

Parental experience of family resources in single-parent families having a child with cancer.

PubMed

Huang, I-Chen; Mu, Pei-Fan; Chiou, Tzeon-Jye

2008-10-01

The purpose of this study was to explore the essence of family experiences in terms of family resources and how these assist a single-parent caring for a child with cancer. When families face stresses caused by cancer, they need to readjust their roles, interactive patterns and relationships, both inside and outside the family. During the adaptation process, family resources may assist recovery from stress and a return to equilibrium. Most research has emphasised the support resources available to two-parent families during the treatment process. There is a lack of information on the experiences of single-parent families and their available resources together with the functions and roles played by family resources during the adjustment process. Qualitative. Five major themes were identified: (i) facing the disease with courage; (ii) hope kindled by professionals; (iii) constructing parental role ability; (iv) assisting the children to live with the illness; and (v) family flexibility. The results of the current study demonstrate that single-parent families with a child suffering from cancer employ family resources to assist family adjustment and to maintain family function/equilibrium. These results explain the dynamic interactions between the multiple levels of resources available to the family. The study results provide evidence-based information that identifies the nature of family resources in single-parent families and describes how these resources can be applied to assist the families.

[A Structural Equation Model on Family Strength of Married Working Women].

PubMed

Hong, Yeong Seon; Han, Kuem Sun

2015-12-01

The purpose of this study was to identify the effect of predictive factors related to family strength and develop a structural equation model that explains family strength among married working women. A hypothesized model was developed based on literature reviews and predictors of family strength by Yoo. This constructed model was built of an eight pathway form. Two exogenous variables included in this model were ego-resilience and family support. Three endogenous variables included in this model were functional couple communication, family stress and family strength. Data were collected using a self-report questionnaire from 319 married working women who were 30~40 of age and lived in cities of Chungnam province in Korea. Data were analyzed with PASW/WIN 18.0 and AMOS 18.0 programs. Family support had a positive direct, indirect and total effect on family strength. Family stress had a negative direct, indirect and total effect on family strength. Functional couple communication had a positive direct and total effect on family strength. These predictive variables of family strength explained 61.8% of model. The results of the study show a structural equation model for family strength of married working women and that predicting factors for family strength are family support, family stress, and functional couple communication. To improve family strength of married working women, the results of this study suggest nursing access and mediative programs to improve family support and functional couple communication, and reduce family stress.

A discussion of HIV/AIDS family interventions: implications for family-focused nursing practice.

PubMed

Eustace, Rosemary W

2013-07-01

This article presents a discussion on the role of family interventions in HIV/AIDS disease prevention and care. Although HIV/AIDS epidemic and its impact on the society traditionally has been measured in terms of individual risk behaviours and individual-level HIV prevention, HIV/AIDS family-focused prevention and management strategies are increasingly becoming a priority. However, little is known as to what constitutes a HIV/AIDS family intervention. The search was limited to English and published literature starting in the year 1983 to date. CINAHL and PubMed were emphasized using a combination of text words and subject headings. Cochrane Library, PsycInfo, Scopus, and the ISI Web of Science databases were also searched using keywords and in the case of PsycInfo, subject headings were used. The main keywords were 'nurse', or 'nursing', 'HIV/AIDS', 'family interventions', 'family support' and 'family education', and/or 'family subsystems'. The process of theorizing about 'family interventions' and 'HIV/AIDS-family interventions' is critical for putting forth essential components unique for designing culturally specific HIV/AIDS family interventions. In addition, any proposed design of HIV/AIDS family intervention should consider the impact of HIV/AIDS on the family across the family life span, disease trajectory, and from an interdisciplinary perspective. Training needs of family nurses should be met when designing multidisciplinary HIV/AIDS-FIs. Furthermore, nurses should be proactive in advocating for HIV/AIDS family intervention and HIV/AIDS family policies to improve outcomes in family functioning, processes, and relationships. More needs to be done in regard to research on families, family interventions, effectiveness, and cost of family-focused approaches. © 2012 Blackwell Publishing Ltd.

A structural model of family empowerment for families of children with special needs.

PubMed

Han, Kuem Sun; Yang, Yunkyung; Hong, Yeong Seon

2018-03-01

To explain and predict family empowerment in families of children with special needs. Family empowerment of families of children with special needs can be explained using the Double ABCX model. Although constant stressors such as parenting stress and family demands can have negative effects on family empowerment, family resources and parenting efficacy can mediate the negative effect through effective coping strategies. A cross-sectional research design was employed. A survey was conducted with 240 parents of children with special needs. Upon exclusion of four responses deemed inadequate to the statistics process, 236 responses were selected for the analysis. Based on the items used in the previous research, we used the scale of family demands 38, the scale of parenting stress 24, the scale of parenting efficacy 37, the scale of pattern of organisation 30, the scale of communication process 16 and the scale of family empowerment 32. In families of children with special needs, parenting stress had a negative effect on parenting efficacy and family resources, namely, pattern of organisation and communication process. Family needs had a positive effect on parenting efficacy. Parenting stress and family demands influenced family empowerment through parenting efficacy and family resources (pattern of organisation and communication process), while parenting efficacy contributed to family empowerment. This study empirically analysed the usefulness of the Double ABCX model in predicting family empowerment. Family resource factors (organisation pattern and communication process) and perception or judgement factors (such as parenting efficacy) were found to mediate the negative impact of various stressors experienced by families of children with special needs. The study findings suggest that clinical practice and management should focus on providing efficient intervention methods to lower stress in families of children with special needs. Reinforcing factors contributing to family empowerment, such as parenting efficacy, organisation pattern and communication process, will alleviate families' stress, resulting in a positive educational and developmental impact on children with special needs. © 2017 John Wiley & Sons Ltd.

Family resources study: part 1: family resources, family function and caregiver strain in childhood cancer

PubMed Central

2011-01-01

Background Severe illness can disrupt family life, cause family dysfunction, strain resources, and cause caregiver burden. The family's ability to cope with crises depends on their resources. This study sought to assess families of children with cancer in terms of family function-dysfunction, family caregiver strain and the adequacy of family resources using a new family resources assessment instrument. Methods This is a cross-sectional study involving 90 Filipino family caregivers of children undergoing cancer treatment. This used a self-administered questionnaire composed of a new 12-item family resources questionnaire (SCREEM-RES) based on the SCREEM method of analysis, Family APGAR to assess family function-dysfunction; and Modified Caregiver Strain Index to assess strain in caring for the patient. Results More than half of families were either moderately or severely dysfunctional. Close to half of caregivers were either predisposed to strain or experienced severe strain, majority disclosed that their families have inadequate economic resources; many also report inaccessibility to medical help in the community and insufficient educational resources to understand and care for their patients. Resources most often reported as adequate were: family's faith and religion; help from within the family and from health providers. SCREEM-RES showed to be reliable with Cronbach's alpha of 0.80. There is good inter-item correlation between items in each domain: 0.24-0.70. Internal consistency reliability for each domain was also good: 0.40-0.92. Using 2-point scoring system, Cronbach's alpha were slightly lower: full scale (0.70) and for each domain 0.26-.82. Results showed evidence of association between family resources and family function based on the family APGAR but none between family resources and caregiver strain and between family function and caregiver strain. Conclusion Many Filipino families of children with cancer have inadequate resources, especially economic; and are moderately or severely dysfunctional. Many caregivers are predisposed to caregiver strain or are already experiencing severe strain. To provide appropriate care for these families, physicians should regularly assess family function, resources and strain experienced by caregivers. The SCREEM-RES questionnaire used in this study is a helpful and reliable instrument to assess adequacy of family resources. PMID:22040272

Work, Family, and Mental Health: Testing Different Models of Work-Family Fit.

ERIC Educational Resources Information Center

Grzywacz, Joseph G.; Bass, Brenda L.

2003-01-01

Using family resilience theory, this study examined the effects of work-family conflict and work-family facilitation on mental health among working adults to gain a better understanding of work-family fit. Results suggest that family to work facilitation is a family protective factor that offsets and buffers the deleterious effects of work-family…

Family Involvement in PSE: International Schools Easing the Transition of Mobile Families

ERIC Educational Resources Information Center

McLachlan, Debra A.

2008-01-01

The impact of family mobility from domestic or international moves can be challenging for families. Some families adjust and other families experience crisis. For some families, relocation may be due to a job promotion and transfer, while for other families moving may be due to divorce, loss of employment or other stressful circumstances.…

Human Service Employees Coping with Job Stress, Family Stress and Work-Family Conflict.

ERIC Educational Resources Information Center

Carbone, Dominic J.

The intersection of work and family life has always been a popular topic of discussion among family theorists. This study examined human service employees in direct service positions coping with work stress, family stress, and work-family conflict. The effects of work stress, family stress and work-family conflict on depression were examined.…

Family Demands, Social Support and Family Functioning in Taiwanese Families Rearing Children with Down Syndrome

ERIC Educational Resources Information Center

Hsiao, C-Y.

2014-01-01

Background: Down syndrome (DS) affects not only children but also their families. Much remains to be learned about factors that influence how families of children with DS function, especially families in non-Western populations. The purpose of this cross-sectional, correlational study was to examine how family demographics, family demands and…

A Perfect Fit: Connecting Family Therapy Skills to Family Business Needs

ERIC Educational Resources Information Center

Cole, Patricia M.; Johnson, Kit

2012-01-01

The purpose of this article is to encourage family therapists to become more interested in family business practice. It does so in three ways: (a) highlighting the number of therapists already involved in family business issues; (b) showing the parallels between family business and family therapy by applying family business research findings to…

[THE NEW FAMILY TYPES IN THE HEALTH SYSTEM].

PubMed

Grau Rubio, Claudia; Fernández Hawrylak, María

2015-11-01

Changes in the Spanish families are critical in the planning of health services, in the evolution oftheirdemands, and in their relationships with healthcare staff We describe the characteristics of the new family structures (single-parent families, LGBT families, older families, multiple birth families, stepfamilies, adoptive families and families that resort to assisted reproductive techniques), what are their concerns, their needs and their requirements, and what are the implications for the health system.

Bridging the gap from values to actions: a family systems framework for family-centered AAC services.

PubMed

Mandak, Kelsey; O'Neill, Tara; Light, Janice; Fosco, Gregory M

2017-03-01

Despite the growing recognition of the importance of family involvement in augmentative and alternative communication (AAC) intervention, little guidance exists on how professionals can establish successful collaborative relationships with families. In this paper, we discuss family systems theory and ecological systems theory as a framework to guide family-centered AAC practice, review family-focused research in AAC, consider how AAC may impact the family system, and provide examples of the clinical implications of using the proposed family systems framework to improve family-centered AAC practice.

Family Involvement and Parent-Teacher Relationships for Students with Autism Spectrum Disorders

PubMed Central

Garbacz, S. Andrew; McIntyre, Laura Lee; Santiago, Rachel T.

2016-01-01

Family educational involvement and parent-teacher relationships are important for supporting student outcomes and have unique implications for families of children with autism spectrum disorder (ASD). However, little research has examined child and family characteristics among families of children with ASD as predictors of family involvement and parent-teacher relationships. The present study examined child and family variables that may affect family involvement and parent-teacher relationships for families of children with ASD. Findings suggested (a) parents of children with higher developmental risk reported less family involvement and poorer relationships with their child's teacher and (b) family histories accessing services predicted family involvement and parent-teacher relationships. Limitations of the current study and implications for science and practice are discussed. PMID:27929318

[Family dysfunction and paediatric patients with asthma].

PubMed

Guzmán-Pantoja, Jaime Eduardo; Reyes Barajas-Mendoza, Eduardo; Luce-González, Elba Graciela; Valadez-Toscano, Francisco Javier; Gutiérrez-Román, Elsa Armida; Robles-Romero, Miguel Angel

2008-11-01

To determine family function of pediatric patients with asthma. Cross-sectional study. Family medicine clinic number 51, Mexican Institute of Social Security, Primary Care, in Guadalajara, Jalisco, Mexico. Fifty families were studied; 25 of which had a pediatric patient previously diagnosed with asthma, and a control group of 25 with pediatric patients without asthma. From September 2006 to February 2007 family function was evaluated using family APGAR and associations were estimated using odds ratio (OR) and 95% confidence interval (CI). Family dysfunction was more often present in families with asthmatic patients compared to those without; OR=3.7 (95% CI, 1.1-13). Severe dysfunction is markedly higher in families with asthmatic members. Family dysfunction is more frequent in families with asthmatic children; family functionality should be seen as an important part of the integral approach in those families.

Si dios quiere: Hispanic families' experiences of caring for a seriously mentally ill family member.

PubMed

Guarnaccia, P J; Parra, P; Deschamps, A; Milstein, G; Argiles, N

1992-06-01

Among Hispanics, the family is viewed as the primary care giver for seriously mentally ill family members. This paper reports on a study of minority families' conceptions of serious mental illness, of their interaction with mental health resources, and on the burdens experienced by families in caring for a seriously mentally ill family member. The focus of this paper is on Hispanic families in New Jersey, with some comparative data from other ethnic group families. Families' conceptions of serious mental illness are explored and analyzed to demonstrate the importance of concepts of nervios and fallo mental in shaping families' responses to their ill family member. Social support systems for families are also explored with particular attention to the role of religious institutions and religious healing as a major source of solace.

Associations of family meal frequency with family meal habits and meal preparation characteristics among families of youth with type 1 diabetes

PubMed Central

Kornides, M. L.; Nansel, T. R.; Quick, V.; Haynie, D. L.; Lipsky, L. M.; Laffel, L. M. B.; Mehta, S. N.

2014-01-01

Background While benefits of family mealtimes, such as improved dietary quality and increased family communication, have been well-documented in the general population, less is known about family meal habits that contribute to more frequent family meals in youth with type 1 diabetes. Methods This cross-sectional study surveyed 282 youth ages 8–18 years with type 1 diabetes and their parents on measures regarding diabetes-related and dietary behaviours. T-tests determined significant differences in youth's diet quality, adherence to diabetes management and glycaemic control between those with and without regular family meals (defined as ≥5 meals per week). Logistic regression analyses determined unadjusted and adjusted associations of age, socio-demographics, family meal habits, and family meal preparation characteristics with regular family meals. Results 57% of parents reported having regular family meals. Families with regular family meals had significantly better diet quality as measured by the Healthy Eating Index (P < 0.05) and the NRF9.3 (P < 0.01), and adherence to diabetes management (P < 0.001); the difference in glycaemic control approached statistical significance (P = 0.06). Priority placed on, pleasant atmosphere and greater structure around family meals were each associated with regular family meals (P < 0.05). Meals prepared at home were positively associated with regular family meals, while convenience and fast foods were negatively associated (P < 0.05). Families in which at least one parent worked part-time or stayed at home were significantly more likely to have regular family meals than families in which both parents worked full-time (P < 0.05). In the multivariate logistic regression model, greater parental priority given to family mealtimes (P < 0.001) and more home-prepared meals (P < 0.001) predicted occurrence of regular family meals; adjusting for parent work status and other family meal habits. Conclusions Strategies for promoting families meals should not only highlight the benefits of family meals, but also facilitate parents' skills for and barriers to home-prepared meals. PMID:23731337

Associations of family meal frequency with family meal habits and meal preparation characteristics among families of youth with type 1 diabetes.

PubMed

Kornides, M L; Nansel, T R; Quick, V; Haynie, D L; Lipsky, L M; Laffel, L M B; Mehta, S N

2014-05-01

While benefits of family mealtimes, such as improved dietary quality and increased family communication, have been well-documented in the general population, less is known about family meal habits that contribute to more frequent family meals in youth with type 1 diabetes. This cross-sectional study surveyed 282 youth ages 8-18 years with type 1 diabetes and their parents on measures regarding diabetes-related and dietary behaviours. T-tests determined significant differences in youth's diet quality, adherence to diabetes management and glycaemic control between those with and without regular family meals (defined as ≥ 5 meals per week). Logistic regression analyses determined unadjusted and adjusted associations of age, socio-demographics, family meal habits, and family meal preparation characteristics with regular family meals. 57% of parents reported having regular family meals. Families with regular family meals had significantly better diet quality as measured by the Healthy Eating Index (P < 0.05) and the NRF9.3 (P < 0.01), and adherence to diabetes management (P < 0.001); the difference in glycaemic control approached statistical significance (P = 0.06). Priority placed on, pleasant atmosphere and greater structure around family meals were each associated with regular family meals (P < 0.05). Meals prepared at home were positively associated with regular family meals, while convenience and fast foods were negatively associated (P < 0.05). Families in which at least one parent worked part-time or stayed at home were significantly more likely to have regular family meals than families in which both parents worked full-time (P < 0.05). In the multivariate logistic regression model, greater parental priority given to family mealtimes (P < 0.001) and more home-prepared meals (P < 0.001) predicted occurrence of regular family meals; adjusting for parent work status and other family meal habits. Strategies for promoting families meals should not only highlight the benefits of family meals, but also facilitate parents' skills for and barriers to home-prepared meals. © 2013 John Wiley & Sons Ltd.

Family-nurse co-construction of meaning: a central phenomenon of family caring.

PubMed

Meiers, Sonja J; Tomlinson, Patricia S

2003-06-01

The purpose of the study was to understand and interpret caring in the family health experience by exploring the interactional phenomenon of family-nurse co-construction of meaning in the paediatric intensive care unit (PICU). A hermeneutic phenomenological method within a framework of existentialism and symbolic interactionism was used in the investigation. The convenience sample for this study was four family-nurse dyads, that is four families of critically ill children (all with positive outcomes) and the four nurses assigned to their care who were participating in a larger study. Data were derived from semi-structured interviews regarding significant interactions throughout the child's illness and subsequent significant interactions of families with other nurses and nurses with other families. Trustworthiness of the study was addressed through the criteria of credibility, dependability, transferability and confirmability. Co-construction of meaning in the family health experience was found to have two dimensions: interdependent and independent. Both families and nurses described being like family as an essential component of the interdependent experience. Independent dimensions for families were journeying through troubled waters of learning the meaning of the illness event and sensing family comfort through the nurse's care. Independent dimensions described by nurses were journeying through troubled waters of learning to care for families and living with another's fear. The family-nurse interaction, the relational connection and the evolution of meanings that families and nurses construct, was affirmed as the major vehicle in the co-construction experience. Family caring is influenced by the existential meaning constructing, process-oriented, interactional nature of the family health experience. Caring in the family health experience is enhanced through actions the nurse performs on behalf of, and with, the family while understanding the family's unique situation. Caring enacted by nurses in participation with families holds abundant potential for enhancing the family health experience and honor the ethic of caring as central to nursing.

Perceived Family Functioning Predicts Baseline Psychosocial Characteristics in U.S. Participants of a Family Focused Grief Therapy Trial.

PubMed

Schuler, Tammy A; Zaider, Talia I; Li, Yuelin; Masterson, Melissa; McDonnell, Glynnis A; Hichenberg, Shira; Loeb, Rebecca; Kissane, David W

2017-07-01

Screening and baseline data on 170 American families (620 individuals), selected by screening from a palliative care population for inclusion in a randomized controlled trial of family-focused grief therapy, were examined to determine whether family dysfunction conferred higher levels of psychosocial morbidity. We hypothesized that greater family dysfunction would, indeed, be associated with poorer psychosocial outcomes among palliative care patients and their family members. Screened families were classified according to their functioning on the Family Relationships Index (FRI) and consented families completed baseline assessments. Mixed-effects modeling with post hoc tests compared individuals' baseline psychosocial outcomes (psychological distress, social functioning, and family functioning on a different measure) according to the classification of their family on the FRI. Covariates were included in all models as appropriate. For those who completed baseline measures, 191 (30.0%) individuals were in low-communicating families, 313 (50.5%) in uninvolved families, and 116 (18.7%) in conflictual families. Family class was significantly associated (at ps ≤ 0.05) with increased psychological distress (Beck Depression Inventory and Brief Symptom Inventory) and poorer social adjustment (Social Adjustment Scale) for individual family members. The family assessment device supported the concurrent accuracy of the FRI. As predicted, significantly greater levels of individual psychosocial morbidity were present in American families whose functioning as a group was poorer. Support was generated for a clinical approach that screens families to identify those at high risk. Overall, these baseline data point to the importance of a family-centered model of care. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Family functioning and perceived support from nurses during cancer treatment among Danish and Australian patients and their families.

PubMed

Dieperink, Karin B; Coyne, Elisabeth; Creedy, Debra K; Østergaard, Birte

2018-01-01

This study aimed to compare family functioning and perceptions of support from nurses among Danish and Australian adult oncology patients and family members. Family can have a strong influence on the health of individuals, providing support during a health crisis such as cancer. However, family functioning and supportive care from nurses may vary across cultures and settings. A descriptive, cross-sectional comparative design with patients and family members from Denmark and Australia. Participants were asked to fill in translated versions of the Iceland-Expressive Family Functioning Questionnaire (ICE-EFFQ) and Iceland-Expressive Family Perceived Support Questionnaire (ICE-FPSQ). In total, 232 participants were recruited. The Danish cohort consisted of 56 patients and 54 family members. The Australian cohort consisted of 83 patients and 39 family members. Mean age was 59 years. No significant differences were found between Danish and Australian families. However, compared to patients, family members reported significantly lower overall family functioning, expressive emotions and communication, as well as less emotional support from nurses. Family functioning was comparable between Denmark and Australia. Family members reported less emotional support than patients. Nurses need to consider the patient and the family as a unit with complex needs that require monitoring and attention during oncology treatment. Families supporting a member with cancer have significant and often unmet needs. Assessment, information-sharing and health education need to include the family. Supportive care information may be shared between Denmark and Australia and inspires the development of common guidelines for optimal family nursing practice. © 2017 John Wiley & Sons Ltd.

Synthesis, solubilization, and surface functionalization of highly fluorescent quantum dots for cellular targeting through a small molecule

NASA Astrophysics Data System (ADS)

Galloway, Justin F.

To achieve long-term fluorescence imaging with quantum dots (QDs), a CdSe core/shell must first be synthesized. The synthesis of bright CdSe QDs is not trivial and as a consequence, the role of surfactant in nucleation and growth was investigated. It was found that the type of surfactant used, either phosphonic or fatty acid, played a pivotal role in the size of the CdSe core. The study of surfactant on CdSe synthesis, ultimately led to an electrical passivation method that utilized a short-chained phosphonic acid and highly reactive organometallic precursors to achieve high quantum yield (QY) as has been previously described. The synthesis of QDs using organometallic precursors and a phosphonic acid for passivation resulted in 4 out of 9 batches of QDs achieving QYs greater than 50% and 8 out of 9 batches with QYs greater than 35%. The synthesis of CdSe QDs was done in organic solutions rendering the surface of the particle hydrophobic. To perform cell-targeting experiments, QDs must be transferred to water. The transfer of QDs to water was successfully accomplished by using single acyl chain lipids. A systematic study of different lipid combinations and coatings demonstrated that 20-40 mol% single acyl chained lipids were able to transfer QDs to water resulting in monodispersed, stable QDs without adversely affecting the QY. The advantage to water solubilization using single acyl chain lipids is that the QD have a hydrodynamic radius less than 15 nm, QYs that can exceed 50% and additional surface functionalization can be down using the reactive sites incorporated into the lipid bilayer. QDs that are bright and stable in water were studied for the purpose of targeting G protein-coupled Receptors (GPCR). GPCRs are transmembrane receptors that internalize extracellular cues, and thus mediate signal transduction. The cyclic Adenosine Monophosphate Receptor 1 of the model organism Dictyostelium disodium was the receptor of interest. The Halo protein, a genetically modified dehalogenase, was added to the N-terminus of the cAR1 receptor without resulting in a phenotype. The Halo protein fused to cAR1 was then shown to bind an organic fluorophore by the cleavage of a chloroalkane bond. Though QDs functionalized with a chloroalkane were able to bind free Halo protein, no specific binding to the Halo protein fused to cAR1 was observed.

A Functional Genomic Approach to Chlorinated Ethenes Bioremediation

NASA Astrophysics Data System (ADS)

Lee, P. K.; Brodie, E. L.; MacBeth, T. W.; Deeb, R. A.; Sorenson, K. S.; Andersen, G. L.; Alvarez-Cohen, L.

2007-12-01

With the recent advances in genomic sciences, a knowledge-based approach can now be taken to optimize the bioremediation of trichloroethene (TCE). During the bioremediation of a heterogeneous subsurface, it is vital to identify and quantify the functionally important microorganisms present, characterize the microbial community and measure their physiological activity. In our field experiments, quantitative PCR (qPCR) was coupled with reverse-transcription (RT) to analyze both copy numbers and transcripts expressed by the 16S rRNA gene and three reductive dehalogenase (RDase) genes as biomarkers of Dehalococcoides spp. in the groundwater of a TCE-DNAPL site at Ft. Lewis (WA) that was serially subjected to biostimulation and bioaugmentation. Genes in the Dehalococcoides genus were targeted as they are the only known organisms that can completely dechlorinate TCE to the innocuous product ethene. Biomarker quantification revealed an overall increase of more than three orders of magnitude in the total Dehalococcoides population and quantification of the more liable and stringently regulated mRNAs confirmed that Dehalococcoides spp. were active. Parallel with our field experiments, laboratory studies were conducted to explore the physiology of Dehalococcoides isolates in order to develop relevant biomarkers that are indicative of the metabolic state of cells. Recently, we verified the function of the nitrogenase operon in Dehalococcoides sp. strain 195 and nitrogenase-encoding genes are ideal biomarker targets to assess cellular nitrogen requirement. To characterize the microbial community, we applied a high-density phylogenetic microarray (16S PhyloChip) that simultaneous monitors over 8,700 unique taxa to track the bacterial and archaeal populations through different phases of treatment. As a measure of species richness, 1,300 to 1,520 taxa were detected in groundwater samples extracted during different stages of treatment as well as in the bioaugmentation culture. We found that the community structure was sensitive to manipulation such as the injection of whey. In addition to Dehalococcoides spp., the PhyloChip also detected dechlorinating bacteria from other phyla such as Sulfurospirillum multivorans and Dehalobacter restrictus. Although these organisms only dechlorinate TCE to dichloroethene, their populations increase at the site over time suggested they also played an important role. Over 600 subfamilies were also found to be active in the microbial community with many of those being important players in geochemical processes. Overall, through the use of high throughput molecular techniques, a comprehensive view of the functionally important organisms and the microbial community was obtained, providing knowledge that can be used to guide the manipulation of the bioremediation processes to achieve the most efficient treatment.

Homoacetogenesis in Deep-Sea Chloroflexi, as Inferred by Single-Cell Genomics, Provides a Link to Reductive Dehalogenation in Terrestrial Dehalococcoidetes.

PubMed

Sewell, Holly L; Kaster, Anne-Kristin; Spormann, Alfred M

2017-12-19

The deep marine subsurface is one of the largest unexplored biospheres on Earth and is widely inhabited by members of the phylum Chloroflexi In this report, we investigated genomes of single cells obtained from deep-sea sediments of the Peruvian Margin, which are enriched in such Chloroflexi 16S rRNA gene sequence analysis placed two of these single-cell-derived genomes (DscP3 and Dsc4) in a clade of subphylum I Chloroflexi which were previously recovered from deep-sea sediment in the Okinawa Trough and a third (DscP2-2) as a member of the previously reported DscP2 population from Peruvian Margin site 1230. The presence of genes encoding enzymes of a complete Wood-Ljungdahl pathway, glycolysis/gluconeogenesis, a Rhodobacter nitrogen fixation (Rnf) complex, glyosyltransferases, and formate dehydrogenases in the single-cell genomes of DscP3 and Dsc4 and the presence of an NADH-dependent reduced ferredoxin:NADP oxidoreductase (Nfn) and Rnf in the genome of DscP2-2 imply a homoacetogenic lifestyle of these abundant marine Chloroflexi We also report here the first complete pathway for anaerobic benzoate oxidation to acetyl coenzyme A (CoA) in the phylum Chloroflexi (DscP3 and Dsc4), including a class I benzoyl-CoA reductase. Of remarkable evolutionary significance, we discovered a gene encoding a formate dehydrogenase (FdnI) with reciprocal closest identity to the formate dehydrogenase-like protein (complex iron-sulfur molybdoenzyme [CISM], DET0187) of terrestrial Dehalococcoides/Dehalogenimonas spp. This formate dehydrogenase-like protein has been shown to lack formate dehydrogenase activity in Dehalococcoides/Dehalogenimonas spp. and is instead hypothesized to couple HupL hydrogenase to a reductive dehalogenase in the catabolic reductive dehalogenation pathway. This finding of a close functional homologue provides an important missing link for understanding the origin and the metabolic core of terrestrial Dehalococcoides/Dehalogenimonas spp. and of reductive dehalogenation, as well as the biology of abundant deep-sea Chloroflexi IMPORTANCE The deep marine subsurface is one of the largest unexplored biospheres on Earth and is widely inhabited by members of the phylum Chloroflexi In this report, we investigated genomes of single cells obtained from deep-sea sediments and provide evidence for a homacetogenic lifestyle of these abundant marine Chloroflexi Moreover, genome signature and key metabolic genes indicate an evolutionary relationship between these deep-sea sediment microbes and terrestrial, reductively dehalogenating Dehalococcoides . Copyright © 2017 Sewell et al.

Biosynthetic Approaches to Isotope Enrichment for Applications in Neutron Scattering and High Field NMR Spectroscopy: Methylotrophic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mary E. lidstrom

Limitations in current isotopic labeling methods present a substantial bottleneck for the application of advanced structural techniques to many important biochemical problems. New tools are required to efficiently produce the necessary labeling patterns in biochemical precursors and incorporate them into protein molecules for structural studies. This project proposed involved one aspect of this problem, the development of expression vectors for a methylotrophic bacterium, Methylobacterium extorquens AM1. If high-level, efficient expression could be obtained in such a bacterium, it would be possible to use low-cost {sup 2}H- and/or {sup 13}C-labeled substrates such as methanol to label proteins. The Lidstrom laboratory atmore » the University of Washington worked closely with the collaborators at Los Alamos National Laboratories in the development and use of these vectors. (1) Overexpression of a target gene, bacterial dehalogenase--This enzyme was expressed in Methylobacterium extorquens AM1 using a high level methanol-inducible promoter, the mxaF promoter. High expression was achieved, but most was in an insoluble form. They expressed this protein in a mutant lacking polybetahydroxybutyrate granules, and high expression was achieved, up to 10% of the total soluble protein. The recombinant protein was purified and shown to be active, with characteristics similar to the enzyme produced in E. coli. (2) Development of regulated expression systems--A number of regulated promoters were tested in M. extorquens AM1, the most promising of which appeared to be the E. coli lac promoter coupled to the Laciq regulator. The repressor was shown to be active and a chromosomal insertion construct was generated that repressed the low-level lac promoter activity in M. extorquens AM1. However, IPTG induced this system only poorly. A number of studies were carried out leading to the conclusion that IPTG entered the cell but was exported by one or more export pumps. Target genes for such pumps were mutated but none of these showed increased induction. A number of methods were used to permeabilize the cell, and a 2-fold increase in induction was obtained with one of these. The activity of the lac promoter was increased by inserting a recently-identified M. extorquens AM1 enhancer element upstream. The promoter increased in activity 5-6 fold with this addition. In summary, they have developed a suite of expression tools and host mutant strains for expressing a variety of heterologous proteins in this methylotroph. These are now available for testing by the LANL collaborators in labeling reactors to obtain labeled proteins of interest.« less

Are family characteristics associated with attendance at family centered rounds in the PICU?.

PubMed

Drago, Matthew J; Aronson, Paul L; Madrigal, Vanessa; Yau, Jennifer; Morrison, Wynne

2013-02-01

The objective of this study was to identify if family characteristics or opinions affected participation in family centered rounds. Observational study of 431 patient encounters on daily work rounds, followed by 100 questionnaires completed by family members of patients in the unit during observation. PICU at a tertiary care, academic, free-standing children's hospital. Patients and families admitted to the PICU during the observation period. None. The most frequent family members present for rounds were mothers (40%). Race, educational level, age of the family member, age of the child, whether the admission was expected, and whether the family member was a medical professional had no association with whether the family member attended rounds. Both family members who were present and those who were not present felt being at rounds would improve the care of their child (87% vs. 100%, p = 0.57). A family's response that they preferred to attend rounds was the only factor associated with a higher likelihood of attending rounds (odds ratio 3.4, 95% confidence interval 1.1-10.8, p = 0.03). Families feel that participating in family centered rounds improves the care of their children. Those that like attending rounds are more likely to participate in family centered rounds, but family demographic characteristics were not associated with rounds attendance. Future studies are needed to identify barriers to family participation in family centered rounds.

Empowering the "Cheerers": Role of Surgical Intensive Care Unit Nurses in Enhancing Family Resilience.

PubMed

Ellis, Lauren; Gergen, Jessica; Wohlgemuth, Leah; Nolan, Marie T; Aslakson, Rebecca

2016-01-01

Supporting family resilience, the ability of families to rebound from stressful events, is a goal of family nursing. Critical care nurses act as liaisons between patients' families and other clinicians and thus are uniquely situated to promote family resilience. To explore how nurses perceive the experiences of long-stay surgical intensive care unit patients and their families in order to gain insights on how nurses could cultivate family resilience. A qualitative study including semistructured interviews (n = 13) and 4 focus groups (n = 17) with nurses in 3 surgical intensive care units in a large teaching hospital. Three themes were identified: expectations, support, and communication. Nurses noted that clinicians' and families' unrealistic expectations regarding the patient's recovery can foster false hope. Nurses recognized families as "cheerers" who provide support by being involved in patient care and observed how extensive family involvement can be beneficial to patients but overwhelming for families. Nurses noted that communication among providers, families, and patients is the cornerstone of creating meaningful relationships. Nurses stated that with many teams involved, discrepancies in information can occur and often confuse and disturb patients' families. Thus, nurses identified ways to enhance family resilience through routine and consistent communication. Nurses note unique stresses faced by families of patients in surgical intensive care units. Using the family resilience model, nurses can identify and enhance key family resilience factors. ©2016 American Association of Critical-Care Nurses.

A dyadic model of the work-family interface: a study of dual-earner couples in China.

PubMed

Ho, Man Yee; Chen, Xuefei; Cheung, Fanny M; Liu, Huimin; Worthington, Everett L

2013-01-01

This study adopted a spillover-crossover model to examine the roles of personality and perceived social support as antecedents of the work-family interface among dual-earner couples in China. Married couples (N = 306) from 2 major cities in China (Shanghai and Jinan) completed questionnaires measuring a relationship-oriented personality trait (i.e., family orientation), perceived family and work support, and work-family conflict and enhancement. The results showed that family orientation and perceived family support was positively associated with family-to-work enhancement and negatively associated with family-to-work conflict for both husbands and wives. Perceived work support was positively associated with family-to-work enhancement for wives and negatively associated with work-to-family conflict for husbands. Similarities in family orientation between partners were positively correlated with the individual's family-to-work enhancement. This study also illustrated the crossover of the work-family interface between dual-earner couples by using the actor-partner interdependence model. The pattern of associations between personality trait and perceived social support varied by gender. Husbands' family orientation was negatively correlated with work-to-family enhancement experienced by wives, and husbands' perceived work support was positively correlated with work-to-family enhancement experienced by wives. Wives' perceived work support was positively correlated with family-to-work conflict experienced by husbands.

A model of work-family conflict and well-being among Malaysian working women.

PubMed

Aazami, Sanaz; Akmal, Syaqirah; Shamsuddin, Khadijah

2015-01-01

Work and family are the two most important domains in a person's life. Lack of balance between work and family can lead to adverse consequences such as psychological distress; however, the effect of work-family conflict on psychological distress might be mediated by job and family dissatisfaction. This study examines a model of the four dimensions of work-family conflict and their consequences on psychological distress. In particular, we test whether job and family satisfaction mediate the effect of the four dimensions of work-family conflict on psychological distress. This cross-sectional study was conducted among 567 Malaysian women who are working in the public services. Structural Equation Modeling confirmed the mediating role of family satisfaction in the effect of strain-based work interference into family and time-based family interference into work on psychological distress. In addition, our results revealed a significant path that links job to family satisfaction. Moreover, time-based work interference into family and strain-based family interference into work significantly and negatively affect job satisfaction, which in turn influence family satisfaction and eventually affect psychological distress. The results of our study show that organizations need to develop and adapt family friendly policies to mitigate level of employees' work-family conflict.

Family Therapy, Family Practice, and Child and Family Poverty: Historical Perspectives and Recent Developments

ERIC Educational Resources Information Center

Frankel, Harvy; Frankel, Sid

2006-01-01

This paper assesses the engagement of family therapy and family practice with families with children, who are living in poverty. It analyzes four promising models from two perspectives. The first perspective relates to critiques, which have been made of the practice of family therapy with families living in poverty; and the second relates to the…

Family Care Responsibilities and Employment: Exploring the Impact of Type of Family Care on Work-Family and Family-Work Conflict

ERIC Educational Resources Information Center

Stewart, Lisa M.

2013-01-01

This study compared work-family and family-work conflict for employed family caregivers with disability-related care responsibilities in contrast to employed family caregivers with typical care responsibilities. Using data from the 2002 National Study of the Changing Workforce, a population-based survey of the U.S. workforce, formal and informal…

Engaging with Families Is a Challenge: Beliefs among Healthcare Professionals in Forensic Psychiatric Care

PubMed Central

Hörberg, Ulrica; Erlingsson, Christen; Syrén, Susanne

2015-01-01

Being healthcare professionals in the complex field of forensic psychiatry care (FPC) seems particularly challenging. Historically, families have almost been invisible in FPC. The aim of this study was to uncover beliefs among healthcare professionals concerning families of patients admitted for FPC. Using a hermeneutical approach inspired by Gadamer's philosophy, group interviews with healthcare professionals in four Swedish forensic psychiatric clinics were analyzed. Analysis resulted in seven key beliefs. There were three beliefs about families: family belongingness is a resource for the patient; most families are broken and not possible to trust; and most families get in the way of the patient's care. Four beliefs concerned encounters with families: it is important to achieve a balance and control over the family; it is essential to set aside one's own values and morals; family-oriented work is an impossible mission; and family oriented work requires welcoming the families. Despite ethical dilemmas of working with families in FPC, healthcare professionals showed a willingness and desire to work in a more family-oriented manner. More knowledge, understanding, and caring tools are needed in order to meet the needs of the family as well as support the family's resources. PMID:26448874

The Family-centered Action Model of Intervention Layout and Implementation (FAMILI): the example of childhood obesity.

PubMed

Davison, Kirsten K; Lawson, Hal A; Coatsworth, J Douglas

2012-07-01

Parents play a fundamental role in shaping children's development, including their dietary and physical activity behaviors. Yet family-centered interventions are rarely used in obesity prevention research. Less than half of childhood obesity prevention programs include parents, and those that do include parents or a family component seldom focus on sustainable change at the level of the family. The general absence of a family-centered approach may be explained by persistent challenges in engaging parents and families and the absence of an intervention framework explicitly designed to foster family-centered programs. The Family-centered Action Model of Intervention Layout and Implementation, or FAMILI, was developed to address these needs. FAMILI draws on theories of family development to frame research and intervention design, uses a mixed-methods approach to conduct ecologically valid research, and positions family members as active participants in the development, implementation, and evaluation of family-centered obesity prevention programs. FAMILI is intended to facilitate the development of culturally responsive and sustainable prevention programs with the potential to improve outcomes. Although childhood obesity was used to illustrate the application of FAMILI, this model can be used to address a range of child health problems.

Children's loneliness, sense of coherence, family climate, and hope: developmental risk and protective factors.

PubMed

Sharabi, Adi; Levi, Uzi; Margalit, Malka

2012-01-01

The study examined the contributions of individual and familial variables for the prediction of loneliness as a developmental risk and the sense of coherence as a protective factor. The sample consisted of 287 children from grades 5-6. Their loneliness, sense of coherence, hope, effort, and family climate were assessed. Separate hierarchical multiple regression analyses revealed that family cohesion and children's hope contributed to the explanation of the risk and protective outcomes. Yet, the contribution of the family adaptability was not significant. Cluster analysis of the family climate dimensions (i.e., cohesion and adaptability) was performed to clarify the interactive roles of family adaptability together with family cohesion. The authors identified 4 separate family profiles: Children in the 2 cohesive families' clusters (Cohesive Structured Families and Cohesive Adaptable Families) reported the lowest levels of loneliness and the highest levels of personal strengths. Children within rigid and noncohesive family cluster reported the highest levels of loneliness and the lowest levels of children's sense of coherence. The unique role of the family flexibility within nonsupportive family systems was demonstrated. The results further clarified the unique profiles' characteristics of the different family clusters and their adjustment indexes in terms of loneliness and personal strengths.

Engaging with Families Is a Challenge: Beliefs among Healthcare Professionals in Forensic Psychiatric Care.

PubMed

Hörberg, Ulrica; Benzein, Eva; Erlingsson, Christen; Syrén, Susanne

2015-01-01

Being healthcare professionals in the complex field of forensic psychiatry care (FPC) seems particularly challenging. Historically, families have almost been invisible in FPC. The aim of this study was to uncover beliefs among healthcare professionals concerning families of patients admitted for FPC. Using a hermeneutical approach inspired by Gadamer's philosophy, group interviews with healthcare professionals in four Swedish forensic psychiatric clinics were analyzed. Analysis resulted in seven key beliefs. There were three beliefs about families: family belongingness is a resource for the patient; most families are broken and not possible to trust; and most families get in the way of the patient's care. Four beliefs concerned encounters with families: it is important to achieve a balance and control over the family; it is essential to set aside one's own values and morals; family-oriented work is an impossible mission; and family oriented work requires welcoming the families. Despite ethical dilemmas of working with families in FPC, healthcare professionals showed a willingness and desire to work in a more family-oriented manner. More knowledge, understanding, and caring tools are needed in order to meet the needs of the family as well as support the family's resources.

Family caring strategies in neutropenia.

PubMed

Eggenberger, Sandra K; Krumwiede, Norma; Meiers, Sonja J; Bliesmer, Mary; Earle, Patricia

2004-12-01

Aggressive chemotherapy protocols result in neutropenia in approximately half of all patients receiving chemotherapy. Thus, neutropenia continues to be a significant and potentially life-threatening side effect of treatment, even with use of colony-stimulating factors. Families of patients with neutropenia often provide the primary healing environment because most chemotherapy protocols are managed on an outpatient basis. To learn about the family's experience of managing chemotherapy-induced neutropenia (CIN), a grounded-theory methodology was used to analyze data from seven families. The central theme revealed by these families was "turbulent waiting with intensified connections." This meant that when families had a sense of greater vulnerability in response to the waiting after diagnosis of CIN, they connected intensely with each other and healthcare providers. Families reported that connections with nurses became more significant when neutropenia interrupted chemotherapy. Families also developed family caring strategies to manage this period of waiting for the chemotherapy to resume. These strategies included family inquiry, family vigilance, and family balancing. Nurses need to be aware of approaches to support the family's ability to manage CIN. Interventions and approaches constructed from the perspective of a family-professional partnership will enhance the family cancer experience as well as ongoing family growth and function.

Organizational work-family resources as predictors of job performance and attitudes: the process of work-family conflict and enrichment.

PubMed

Odle-Dusseau, Heather N; Britt, Thomas W; Greene-Shortridge, Tiffany M

2012-01-01

The goal of the current study was to test a model where organizational resources (aimed at managing work and family responsibilities) predict job attitudes and supervisor ratings of performance through the mechanisms of work-family conflict and work-family enrichment. Employees (n = 174) at a large metropolitan hospital were surveyed at two time periods regarding perceptions of family supportive supervisor behaviors (FSSB), family supportive organizational perceptions (FSOP), bidirectional work-family conflict, bidirectional work-family enrichment, and job attitudes. Supervisors were also asked to provide performance ratings at Time 2. Results revealed FSSB at Time 1 predicted job satisfaction, organizational commitment and intention to leave, as well as supervisor ratings of performance, at Time 2. In addition, both work-family enrichment and family-work enrichment were found to mediate relationships between FSSB and various organizational outcomes, while work-family conflict was not a significant mediator. Results support further testing of supervisor behaviors specific to family support, as well models that include bidirectional work-family enrichment as the mechanism by which work-family resources predict employee and organizational outcomes.

WORKPLACE SOCIAL SUPPORT AND WORK–FAMILY CONFLICT: A META-ANALYSIS CLARIFYING THE INFLUENCE OF GENERAL AND WORK–FAMILY-SPECIFIC SUPERVISOR AND ORGANIZATIONAL SUPPORT

PubMed Central

KOSSEK, ELLEN ERNST; PICHLER, SHAUN; BODNER, TODD; HAMMER, LESLIE B.

2011-01-01

This article uses meta-analysis to develop a model integrating research on relationships between employee perceptions of general and work–family-specific supervisor and organizational support and work–family conflict. Drawing on 115 samples from 85 studies comprising 72,507 employees, we compared the relative influence of 4 types of workplace social support to work–family conflict: perceived organizational support (POS); supervisor support; perceived organizational work–family support, also known as family-supportive organizational perceptions (FSOP); and supervisor work–family support. Results show work–family-specific constructs of supervisor support and organization support are more strongly related to work–family conflict than general supervisor support and organization support, respectively. We then test a mediation model assessing the effects of all measures at once and show positive perceptions of general and work–family-specific supervisor indirectly relate to work–family conflict via organizational work–family support. These results demonstrate that work–family-specific support plays a central role in individuals’ work–family conflict experiences. PMID:21691415

WORKPLACE SOCIAL SUPPORT AND WORK-FAMILY CONFLICT: A META-ANALYSIS CLARIFYING THE INFLUENCE OF GENERAL AND WORK-FAMILY-SPECIFIC SUPERVISOR AND ORGANIZATIONAL SUPPORT.

PubMed

Kossek, Ellen Ernst; Pichler, Shaun; Bodner, Todd; Hammer, Leslie B

2011-01-01

This article uses meta-analysis to develop a model integrating research on relationships between employee perceptions of general and work-family-specific supervisor and organizational support and work-family conflict. Drawing on 115 samples from 85 studies comprising 72,507 employees, we compared the relative influence of 4 types of workplace social support to work-family conflict: perceived organizational support (POS); supervisor support; perceived organizational work-family support, also known as family-supportive organizational perceptions (FSOP); and supervisor work-family support. Results show work-family-specific constructs of supervisor support and organization support are more strongly related to work-family conflict than general supervisor support and organization support, respectively. We then test a mediation model assessing the effects of all measures at once and show positive perceptions of general and work-family-specific supervisor indirectly relate to work-family conflict via organizational work-family support. These results demonstrate that work-family-specific support plays a central role in individuals' work-family conflict experiences.

Family dynamics across pregnant Latina adolescents' transition to parenthood.

PubMed

East, Patricia L; Chien, Nina C

2010-12-01

Growth curve models were conducted on assessments of family functioning at four time points from the third-trimester of pregnancy through the first year postpartum for 96 Latino families in which an adolescent daughter was pregnant. Results indicated significant family-level change following an adolescent's childbearing, though there were notable differences between family members in their perceptions of family functioning. Family conflict, as perceived by parenting teens, increased in the latter half of the first year after an initial decline, and family companionship (as rated by mothers and siblings) decreased. Parenting adolescents and siblings perceived significant increases in family cohesion, whereas mothers perceived a significant decline. Unplanned pregnancies, family financial hardship, and expected stress predicted unfavorable family functioning at 1 year. Contrary to expectations, adolescents' greater prenatal efforts to prepare for parenting predicted subsequent family conflict and declines in family cohesion (particularly as rated by mothers). Family members' acculturation level and attitudes of familism, gender roles, and the status attained by parenthood also had predictive effects. Implications of study findings for family adjustment following an adolescent's childbearing are discussed.

Bulimia Nervosa: A Review of Family Characteristics.

ERIC Educational Resources Information Center

Lau, DeeAnne Karyl

The purpose of this literature review was to demonstrate that a family systems conceptualization of family dysfunction could be applied to bulimic families. In general, self-report and observational family characteristics studies support the hypothesis that bulimic families, like anorectic families, have significant systemic dysfunction in…

Family System Characteristics, Parental Behaviors, and Adolescent Family Life Satisfaction.

ERIC Educational Resources Information Center

Henry, Carolyn S.

1994-01-01

Describes investigation examining adolescents' perceptions of overall family system characteristics, parental behaviors, and demographic factors in relation to adolescent family life satisfaction. Results indicate family bonding, family flexibility, parental support, and adolescent age are positively related to adolescent family life satisfaction,…

Family Structure and Child Well-Being: Integrating Family Complexity

PubMed Central

Brown, Susan L.; Manning, Wendy D.; Stykes, J. Bart

2014-01-01

Although children’s family lives are diverse, the measurement of children’s living arrangements has lagged, focusing on the relationships of children to parents while largely ignoring sibling composition. Using data from the 2008 Survey of Income and Program Participation (N = 23,985) the authors documented patterns of family complexity among a nationally representative sample of children ages 0–17 living in a range of family structures. They also examined the independent and joint associations of family structure and family complexity on child economic well-being. Family complexity was independently related to economic disadvantage, namely, a lower income-to-needs ratio and a higher likelihood of public assistance receipt. The role of family complexity was partially contingent on family structure, with the positive association between family complexity and receipt of public assistance more pronounced for children in families with 2 married biological parents. This study demonstrates the utility of integrating family structure and family complexity in studies of children’s well-being. PMID:25620810

Family psychology: Past and future reflections on the field.

PubMed

Parke, Ross D

2017-04-01

Prominent issues in the field of family psychology during my term as editor (1998-2003) of this journal were briefly noted, including a focus on marital issues, divorce, remarriage and family conflict. Parenting, attachment and parent-child relationships were also significant topics in this period. Special sections of the journal focused on cultural variations, families and the law, families and religion, and family routines and rituals. Several neglected issues that need more attention in the future were noted. These include the need to recognize the embeddedness of families in socioecological contexts, the importance of monitoring the impact of secular changes on families, and the value and limitations of viewing family psychology as a separate field. Other topics for a future agenda include the challenge of defining "family" in the midst of changing family forms, the effects of technological change on families, and the challenges of integrating biological research into the family psychology agenda. A multilevel bio-social approach to family research was recommended. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Family and family therapy in the Netherlands.

PubMed

Wagenaar, Karin; Baars, Jan

2012-04-01

This article describes how families are functioning in the Netherlands, and how family therapy is used in mental healthcare. In the open Dutch society, new ideas are easily incorporated, as exemplified by the rapid introduction and growth of family therapy in the 1980s. In recent decades, however, family therapy has lost ground to other treatment models that are more individually orientated, and adhere to stricter protocols. This decline of family therapy has been exacerbated by recent budget cuts in mental healthcare. In regular healthcare institutes family therapy now has a marginal position at best, although family treatment models are used in specific areas such as forensic treatments. In addition, the higher trained family therapists have found their own niches to work with couples and families. We argue that a stronger position of family therapy would be beneficial for patients and for families, in order to counteract the strong individualization of Dutch society.

Indicators of family resilience after the death of a child.

PubMed

Greeff, Abraham P; Vansteenwegen, Alfons; Herbiest, Tina

2011-01-01

The aim of this study was to identify and describe resilience qualities in families after losing a child. Questionnaires, including an open-ended question, were utilized to collect data independently from the parents and siblings of the deceased in 89 Belgian families. The results indicate that family strengths in general, and commitment to the family in particular, helped the families' adaptation after the loss. In addition, the adaptation process after the loss was aided if the family members viewed the crisis as a challenge. Both the siblings and the parents indicated that the extent to which a family experienced support from the community was directly related to family adaptation after the loss. Redefining the situation and utilizing social support from friends and family were underlined as effective family coping strategies. The findings could be used in interventions to promote family resilience, thereby affirming the reparative potential of families.

"Not a Real Family": Microaggressions Directed toward LGBTQ Families.

PubMed

Haines, Kari M; Boyer, C Reyn; Giovanazzi, Casey; Galupo, M Paz

2018-01-01

The present study investigates microaggressions toward individuals in lesbian, gay, bisexual, transgender, and queer (LGBTQ) families. Microaggressions are subtle forms of discrimination experienced on a daily basis as verbal or behavioral slights against individuals in oppressed groups. LGBTQ microaggressions are often studied at an individual level and understood as being directed toward an individual based on perceived identity. The present study allows for an understanding of bias directed at the family system level. Participants included 46 adults who identified as being part of an LGBTQ family. Participants completed an online questionnaire and described their experiences of LGBTQ family microaggressions. Thematic analysis revealed that LGBTQ family microaggressions were salient to individuals across multiple family roles. Three specific themes emerged: family legitimacy, conflicts with family values, and gender violation within family. These findings highlight the way LGBTQ microaggressions are influenced by cultural notions of family and impact the family system.

The relationship among work-family conflict and enhancement, organizational work-family culture, and work outcomes for older working women.

PubMed

Gordon, Judith R; Whelan-Berry, Karen S; Hamilton, Elizabeth A

2007-10-01

This article examines the relationship among work-family conflict and enhancement, organizational work-family culture, and four work outcomes for 489 working women over the age of 50. Survey results from two U.S. health care organizations and one U.S. financial services organization indicate that older working women experience differing amounts of work-to-family conflict, family-to-work conflict, work-to-family enhancement, and family-to-work enhancement. Hypotheses relating organizational work-family culture to work-family conflict and enhancement were partially supported, and hypotheses relating conflict and enhancement to four work outcomes were partially supported. Work-to-family conflict and work-to-family enhancement partially mediate the relationship between organizational work-family culture and selected work outcomes. Implications for theory and practice, limitations of this study, and directions for future research are also presented.

Family identity: black-white interracial family health experience.

PubMed

Byrd, Marcia Marie; Garwick, Ann Williams

2006-02-01

The purpose of this interpretive descriptive study was to describe how eight Black-White couples with school-aged children constructed their interracial family identity through developmental transitions and interpreted race to their children. Within and across-case data analytic strategies were used to identify commonalities and variations in how Black men and White women in couple relationships formed their family identities over time. Coming together was the core theme described by the Black-White couples as they negotiated the process of forming a family identity. Four major tasks in the construction of interracial family identity emerged: (a) understanding and resolving family of origin chaos and turmoil, (b) transcending Black-White racial history, (c) articulating the interracial family's racial standpoint, and (d) explaining race to biracial children across the developmental stages. The findings guide family nurses in promoting family identity formation as a component of family health within the nurse-family partnership with Black-White mixed-race families.

Natural disasters: an assessment of family resiliency following Hurricane Katrina.

PubMed

Hackbarth, Maria; Pavkov, Thomas; Wetchler, Joseph; Flannery, Michael

2012-04-01

This study explored the role of family characteristics in the coping process of a family after having experienced Hurricane Katrina to gain an understanding of the relationship between family resiliency, hope, family hardiness, and spirituality for survivors of this natural disaster. It was hypothesized that families who demonstrate higher levels of hope, family hardiness, and spirituality would be more likely to effectively cope after the storm. Further, great resource loss was hypothesized to diminish a family's ability to cope. Four hundred fifty-two participants completed the survey. Results indicate a relationship between hope, family hardiness and spirituality, and the criterion variable, family coping. The importance of these findings in terms of exploring family resiliency following a natural disaster is discussed. © 2011 American Association for Marriage and Family Therapy.

Examining the impact of child parent relationship therapy (CPRT) on family functioning.

PubMed

Cornett, Nick; Bratton, Sue C

2014-07-01

Research supports that child parent relationship therapy (CPRT), a filial therapy approach, has strong effects on participating parents and children. Some speculate that filial therapy improves the family system; however, minimal research exists to support this claim. Using a single-case design, researchers examined CPRT's impact on the functioning of 8 families. Results revealed that 6 families experienced statistically significant improvements in targeted areas of family functioning. Results from self-reported measures indicated that 7 families improved in family satisfaction, 4 in cohesion, 3 in communication, and 1 in flexibility. Observational measures also revealed improvements: 5 families in flexibility, 4 families in cohesion, and 4 families in communication. The results support that the benefits of CPRT may extend to the family system. © 2013 American Association for Marriage and Family Therapy.

Family Quality of Life of South African Families Raising Children with Autism Spectrum Disorder.

PubMed

Schlebusch, Liezl; Dada, Shakila; Samuels, Alecia E

2017-07-01

This article describes the family quality of life among families who are raising a young child with autism spectrum disorder. Survey research was conducted with 180 families of children with autism spectrum disorder who were receiving disability-related services in the Gauteng province of South Africa. The principle measure used was the Beach Center Family Quality of Life Scale to assess five subdomains: family interaction, parenting, emotional well-being, material/physical well-being, and disability-related support. Results indicated that families felt the most satisfied with disability-related support and the least satisfied with the family's emotional well-being. Family income, family type, and the severity level of autism were significantly associated with how satisfied families felt about their quality of life.

Family involvement and parent-teacher relationships for students with autism spectrum disorders.

PubMed

Garbacz, S Andrew; McIntyre, Laura Lee; Santiago, Rachel T

2016-12-01

Family educational involvement and parent-teacher relationships are important for supporting student outcomes and have unique implications for families of children with autism spectrum disorder (ASD). However, little research has examined child and family characteristics among families of children with ASD as predictors of family involvement and parent-teacher relationships. The present study examined child and family variables that may affect family involvement and parent-teacher relationships for families of children with ASD. Findings suggested (a) parents of children with higher developmental risk reported less family involvement and poorer relationships with their child's teacher and (b) family histories accessing services predicted family involvement and parent-teacher relationships. Limitations of the current study and implications for science and practice are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Predictors of adaptation in Icelandic and American families of young children with chronic asthma.

PubMed

Svavarsdottir, Erla Kolbrun; Rayens, Mary Kay; McCubbin, Marilyn

2005-01-01

The purposes of this international study were to determine the predictors of adaptation and to assess potential moderating effects of parents' sense of coherence and family hardiness on the relationship of severity of illness of a child with asthma and family and caregiving demands as predictors of family adaptation. For both parents, sense of coherence and family hardiness predicted family adaptation. Icelandic mothers perceived their family's adaptation more favorably than did their American counterparts. For the fathers, family demands predicted adaptation. Sense of coherence moderated the effect of family demands on adaptation for both parents. These findings underscore the importance of strengthening individual and family resiliency as a mechanism for improving family adaptation.

Family medical leave as a resilience resource for family caregivers.

PubMed

Swanke, Jayme; Zeman, Laura Dreuth

2009-01-01

Case managers mobilize family networks to care for patients. Family medical leave can be a resource for case managers who seek to enhance resilience among family caregivers. The Family Medical Leave Act, passed in 1993, was the first U.S. policy to regulate employee leaves from work for family care purposes (29 CFR 825.102). This policy offers family caregivers increased flexibility and equality. Current and emerging policies also can reduce financial strain. The discussion examines how case managers can integrate family medical leave into best-practice models to support patients and family caregivers.

Roles within the Family

MedlinePlus

... Adoption & Foster Care Communication & Discipline Types of Families Media Work & Play Getting Involved in Your Community Healthy Children > Family Life > Family Dynamics > Roles Within the Family Family Life Listen Español Text ...

Thinking About Adoption

MedlinePlus

... Life Family Life Family Life Medical Home Family Dynamics Media Work & Play Getting Involved in Your Community ... Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care Communication & Discipline Types of Families ...

The Relationship between Dysfunctional Family Environments and Family Member Food Intake.

ERIC Educational Resources Information Center

Kintner, Martha; And Others

1981-01-01

Explores relationships between family environment and family food intake. Findings indicate a significant negative relationship between the family's dysfunctional environment (indicated by high conflict, control, and organization) and family dietary intake. A significant positive relationship was found between the family's cohesive and independent…

1993--Twenty-Fifth Annual National Council on Family Relations Videotape Competition.

ERIC Educational Resources Information Center

Gentry, Deborah; And Others

1994-01-01

Lists and annotates winning entries in 1993 National Council on Family Relations Videotape Competition in categories of substance abuse, aging, social issues, divorce/remarriage, families with special needs, family violence, human development, reproduction and family planning, marital/family issues, mental health, nontraditional families,…

Using Information and Communication Technologies for Family Communication and Its Association With Family Well-Being in Hong Kong: FAMILY Project.

PubMed

Wang, Man Ping; Chu, Joanna T W; Viswanath, Kasisomayajula; Wan, Alice; Lam, Tai Hing; Chan, Sophia S

2015-08-24

Family communication is central to the family and its functioning. It is a mutual process in which family members create, share, and regulate meaning. Advancement and proliferation of information and communication technologies (ICTs) continues to change methods of family communication. However, little is known about the use of different methods for family communication and the influence on family well-being. We investigated the sociodemographic factors associated with different methods of family communication and how they are associated with perceived family harmony, happiness, and health (3Hs) among Chinese adults in Hong Kong. Data came from a territory-wide probability-based telephone survey using the Family and Health Information Trend survey (FHInTs). Frequency of family communication using different methods (ie, face-to-face, phone, instant messaging [IM], social media sites, and email) were recoded and classified as frequent (always/sometimes) and nonfrequent (seldom/never) use. Family well-being was measured using 3 questions of perceived family harmony, happiness, and health with higher scores indicating better family well-being. Adjusted odds ratios for family communication methods by sociodemographic characteristics and adjusted beta coefficients for family well-being by communication methods were calculated. A total of 1502 adults were surveyed. Face-to-face (94.85%, 1408/1484) was the most frequent means of communication followed by phone (78.08%, 796/1484), IM (53.64%, 796/1484), social media sites (17.60%, 261/1484), and email (13.39%, 198/1484). Younger age was associated with the use of phone, IM, and social media sites for family communication. Higher educational attainment was associated with more frequent use of all modes of communication, whereas higher family income was only significantly associated with more frequent use of IM and email (P=.001). Face-to-face (beta 0.65, 95% CI 0.33-0.97) and phone use (beta 0.20, 95% CI 0.02-0.38) for family communication were associated with significantly higher levels of perceived family well-being. Socioeconomic disparities in using these information and communication technologies (ICT) methods for family communication were observed. Although traditional methods remain as the main platform for family communication and were associated with better family well-being, a notable proportion of respondents are using new ICT methods, which were not associated with perceived family well-being. Because ICTs will continue to diversify modes of family communication, more research is needed to understand the impact of ICTs on family communication and well-being.

Using Information and Communication Technologies for Family Communication and Its Association With Family Well-Being in Hong Kong: FAMILY Project

PubMed Central

Wang, Man Ping; Chu, Joanna TW; Viswanath, Kasisomayajula; Wan, Alice; Chan, Sophia S

2015-01-01

Background Family communication is central to the family and its functioning. It is a mutual process in which family members create, share, and regulate meaning. Advancement and proliferation of information and communication technologies (ICTs) continues to change methods of family communication. However, little is known about the use of different methods for family communication and the influence on family well-being. Objective We investigated the sociodemographic factors associated with different methods of family communication and how they are associated with perceived family harmony, happiness, and health (3Hs) among Chinese adults in Hong Kong. Methods Data came from a territory-wide probability-based telephone survey using the Family and Health Information Trend survey (FHInTs). Frequency of family communication using different methods (ie, face-to-face, phone, instant messaging [IM], social media sites, and email) were recoded and classified as frequent (always/sometimes) and nonfrequent (seldom/never) use. Family well-being was measured using 3 questions of perceived family harmony, happiness, and health with higher scores indicating better family well-being. Adjusted odds ratios for family communication methods by sociodemographic characteristics and adjusted beta coefficients for family well-being by communication methods were calculated. Results A total of 1502 adults were surveyed. Face-to-face (94.85%, 1408/1484) was the most frequent means of communication followed by phone (78.08%, 796/1484), IM (53.64%, 796/1484), social media sites (17.60%, 261/1484), and email (13.39%, 198/1484). Younger age was associated with the use of phone, IM, and social media sites for family communication. Higher educational attainment was associated with more frequent use of all modes of communication, whereas higher family income was only significantly associated with more frequent use of IM and email (P=.001). Face-to-face (beta 0.65, 95% CI 0.33-0.97) and phone use (beta 0.20, 95% CI 0.02-0.38) for family communication were associated with significantly higher levels of perceived family well-being. Conclusions Socioeconomic disparities in using these information and communication technologies (ICT) methods for family communication were observed. Although traditional methods remain as the main platform for family communication and were associated with better family well-being, a notable proportion of respondents are using new ICT methods, which were not associated with perceived family well-being. Because ICTs will continue to diversify modes of family communication, more research is needed to understand the impact of ICTs on family communication and well-being. PMID:26303434

Family Functioning Differences Across the Deployment Cycle in British Army Families: The Perceptions of Wives and Children.

PubMed

Pye, Rachel E; Simpson, Leanne K

2017-09-01

Military deployment can have an adverse effect on a soldier's family, though little research has looked at these effects in a British sample. We investigated wives' of U.K.-serving soldiers perceptions of marital and family functioning, across three stages of the deployment cycle: currently deployed, postdeployment and predeployed, plus a nonmilitary comparison group. Uniquely, young (aged 3.5-11 years) children's perceptions of their family were also investigated, using the parent-child alliance (PCA) coding scheme of drawings of the family. Two hundred and twenty British military families of regular service personnel from the British Army's Royal Armoured Corps, were sent survey packs distributed with a monthly welfare office newsletter. Wives were asked to complete a series of self-report items, and the youngest child in the family between the ages of 3.5 and 11 years was asked to draw a picture of their family. Complete data were available for 78 military families, and an additional 34 nonmilitary families were recruited via opportunity sampling. Results indicated wives of currently deployed and recently returned personnel were less satisfied with their family and its communication, and children's pictures indicated higher levels of dysfunctional parent-child alliance, whereas predeployed families responded similarly to nonmilitary families. Marital satisfaction was similar across all groups except predeployed families who were significantly more satisfied. Nonmilitary and predeployed families showed balanced family functioning, and currently and recently deployed families demonstrated poor family functioning. In comparison to nonmilitary families, predeployed families showed a large "spike" in the rigidity subscale of the Family Adaptability and Cohesion Evaluation Scale IV. Wives' perceptions of family functioning, but not marital satisfaction, differed between the deployment groups. The results from the coded children's drawings correlated with the self-report measures from the wife/mother, indicating that children's drawings could be a useful approach when working with younger children in this area. It is tentatively suggested that the differences across deployment stage on family functioning could be mediated not only by communication difficulties between deployed personnel and their families, but also by its effect on the children in the family. Larger-scale longitudinal research is needed to investigate this further. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

South African Families Raising Children with Autism Spectrum Disorders: Relationship between Family Routines, Cognitive Appraisal and Family Quality of Life

ERIC Educational Resources Information Center

Schlebusch, L.; Samuels, A. E.; Dada, S.

2016-01-01

Background: The purpose of this study was to investigate the relationship between family routines, cognitive appraisal of the impact of autism spectrum disorders (ASD) on the family and family quality of life (FQOL) in families raising children with ASD in South Africa. Methods: A sample of 180 families of young children with ASD who were…

Next-generation leadership development in family businesses: the critical roles of shared vision and family climate.

PubMed

Miller, Stephen P

2014-01-01

The multigenerational survival rate for family-owned businesses is not good. Lack of a shared vision for the family enterprise and weak next-generation leadership are often cited as two of the leading reasons for the failure of family firms to successfully transition from one generation of family ownership to the next. The climate of the business-owning family has also been suggested as important to the performance of the family enterprise. Despite these commonly held tenets, there is a lack of rigorous quantitative research that explores the relationships among these three factors. To address this gap, a quantitative study of 100 next-generation family firm leaders and 350 family and non-family leaders and employees with whom they work was conducted. The results demonstrate that a shared vision for the family business has a strong effect on the leadership effectiveness of next-generation family leaders and a moderate effect on the degree to which they are positively engaged with their work. The findings also show that two dimensions of family climate significantly influence the likelihood that a shared vision for the family firm has been created. Open communication in the family is positively related to the presence of a shared vision for the business. Intergenerational authority, which refers to a senior generation that exercises unquestioned authority and sets the rules, is negatively related to the presence of a shared vision. Surprisingly, a third dimension of family climate, cognitive cohesion, which includes shared values in the family, had no relationship with the degree to which there was a shared vision for the family business. The implications for family business owners is that they would be wise to spend as much time on fostering a positive family climate characterized by open communication as they do on creating and executing a successful business strategy if their goal is to pass the business from one generation of family owners to the next.

Next-generation leadership development in family businesses: the critical roles of shared vision and family climate

PubMed Central

Miller, Stephen P.

2014-01-01

The multigenerational survival rate for family-owned businesses is not good. Lack of a shared vision for the family enterprise and weak next-generation leadership are often cited as two of the leading reasons for the failure of family firms to successfully transition from one generation of family ownership to the next. The climate of the business-owning family has also been suggested as important to the performance of the family enterprise. Despite these commonly held tenets, there is a lack of rigorous quantitative research that explores the relationships among these three factors. To address this gap, a quantitative study of 100 next-generation family firm leaders and 350 family and non-family leaders and employees with whom they work was conducted. The results demonstrate that a shared vision for the family business has a strong effect on the leadership effectiveness of next-generation family leaders and a moderate effect on the degree to which they are positively engaged with their work. The findings also show that two dimensions of family climate significantly influence the likelihood that a shared vision for the family firm has been created. Open communication in the family is positively related to the presence of a shared vision for the business. Intergenerational authority, which refers to a senior generation that exercises unquestioned authority and sets the rules, is negatively related to the presence of a shared vision. Surprisingly, a third dimension of family climate, cognitive cohesion, which includes shared values in the family, had no relationship with the degree to which there was a shared vision for the family business. The implications for family business owners is that they would be wise to spend as much time on fostering a positive family climate characterized by open communication as they do on creating and executing a successful business strategy if their goal is to pass the business from one generation of family owners to the next. PMID:25538639

Determining the familial risk distribution of colorectal cancer: a data mining approach.

PubMed

Chau, Rowena; Jenkins, Mark A; Buchanan, Daniel D; Ait Ouakrim, Driss; Giles, Graham G; Casey, Graham; Gallinger, Steven; Haile, Robert W; Le Marchand, Loic; Newcomb, Polly A; Lindor, Noralane M; Hopper, John L; Win, Aung Ko

2016-04-01

This study was aimed to characterize the distribution of colorectal cancer risk using family history of cancers by data mining. Family histories for 10,066 colorectal cancer cases recruited to population cancer registries of the Colon Cancer Family Registry were analyzed using a data mining framework. A novel index was developed to quantify familial cancer aggregation. Artificial neural network was used to identify distinct categories of familial risk. Standardized incidence ratios (SIRs) and corresponding 95% confidence intervals (CIs) of colorectal cancer were calculated for each category. We identified five major, and 66 minor categories of familial risk for developing colorectal cancer. The distribution the major risk categories were: (1) 7% of families (SIR = 7.11; 95% CI 6.65-7.59) had a strong family history of colorectal cancer; (2) 13% of families (SIR = 2.94; 95% CI 2.78-3.10) had a moderate family history of colorectal cancer; (3) 11% of families (SIR = 1.23; 95% CI 1.12-1.36) had a strong family history of breast cancer and a weak family history of colorectal cancer; (4) 9 % of families (SIR = 1.06; 95 % CI 0.96-1.18) had strong family history of prostate cancer and weak family history of colorectal cancer; and (5) 60% of families (SIR = 0.61; 95% CI 0.57-0.65) had a weak family history of all cancers. There is a wide variation of colorectal cancer risk that can be categorized by family history of cancer, with a strong gradient of colorectal cancer risk between the highest and lowest risk categories. The risk of colorectal cancer for people with the highest risk category of family history (7% of the population) was 12-times that for people in the lowest risk category (60%) of the population. Data mining was proven an effective approach for gaining insight into the underlying cancer aggregation patterns and for categorizing familial risk of colorectal cancer.

The family health, functioning, social support and child maltreatment risk of families expecting a baby.

PubMed

Lepistö, Sari; Ellonen, Noora; Helminen, Mika; Paavilainen, Eija

2017-08-01

To describe the family health, functioning, social support and child maltreatment risk and associations between them in families expecting a baby. Finland was one of the first countries in banning corporal punishment against children over 30 years ago. Despite of this, studies have shown that parents physically abuse their children. In addition, professionals struggle in intervention of this phenomenon. Abusive parents should be recognised and helped before actual violent behaviour. A follow-up case-control study, with a supportive intervention in the case group (families with a heightened risk) in maternity and child welfare clinics. The baseline results of families are described here. Child maltreatment risk in families expecting a baby was measured by Child Abuse Potential Inventory. The health and functioning was measured by Family Health, Functioning and Social Support Scale. Data included 380 families. A total of 78 families had increased risk for child maltreatment. Heightened risk was associated with partners' age, mothers' education, partners' father's mental health problems, mothers' worry about partners' drinking and mothers' difficulties in talking about the family's problems. Risk was associated with family functioning and health. Families with risk received a less support from maternity clinics. Families with child maltreatment risk and related factors were found. This knowledge can be applied for supporting families both during pregnancy and after the baby is born. Professionals working with families in maternity clinics need tools to recognise families with risk and aid a discussion with them about the family life situation. The Child Abuse Potential, as a part of evaluating the family life situation, seems to prove a useful tool in identifying families at risk. The results offer a valid and useful tool for recognising families with risk and provide knowledge about high-risk family situations. © 2016 John Wiley & Sons Ltd.

Determining the familial risk distribution of colorectal cancer: A data mining approach

PubMed Central

Chau, Rowena; Jenkins, Mark A.; Buchanan, Daniel D.; Ouakrim, Driss Ait; Giles, Graham G.; Casey, Graham; Gallinger, Steven; Haile, Robert W.; Le Marchand, Loic; Newcomb, Polly A.; Lindor, Noralane M.; Hopper, John L.; Win, Aung Ko

2016-01-01

This study was aimed to characterize the distribution of colorectal cancer risk using family history of cancers by data mining. Family histories for 10,066 colorectal cancer cases recruited to population cancer registries of the Colon Cancer Family Registry were analyzed using a data mining framework. A novel index was developed to quantify familial cancer aggregation. Artificial neural network was used to identify distinct categories of familial risk. Standardized incidence ratios (SIRs) and corresponding 95% confidence intervals (CIs) of colorectal cancer were calculated for each category. We identified five major, and sixty-six minor categories of familial risk for developing colorectal cancer. The distribution the major risk categories were: (i) 7% of families (SIR=7.11; 95%CI=6.65–7.59) had a strong family history of colorectal cancer; (ii) 13% of families (SIR=2.94; 95%CI=2.78–3.10) had a moderate family history of colorectal cancer; (iii) 11% of families (SIR=1.23; 95%CI=1.12–1.36) had a strong family history of breast cancer and weak family history of colorectal cancer; (iv) 9% of families (SIR=1.06; 95% CI=0.96–1.18) had a strong family history of prostate cancer and a weak family history of colorectal cancer; and (v) 60% of families (SIR=0.61; 95%CI=0.57–0.65) had weak family history of all cancers. There is a wide variation of colorectal cancer risk that can be categorized by family history of cancer, with a strong gradient of colorectal cancer risk between the highest and lowest risk categories. The risk of colorectal cancer for people with the highest risk category of family history (7% of the population) was 12-times that for people in the lowest risk category (60%) of the population. Data mining was proven an effective approach for gaining insight into the underlying cancer aggregation patterns and for categorizing familial risk of colorectal cancer. PMID:26681340

Families and Health: An Empirical Resource Guide for Researchers and Practitioners

ERIC Educational Resources Information Center

Proulx, Christine M.; Snyder, Linley A.

2009-01-01

As evidence mounts indicating that the quality of family relationships affects family member health and that the health of family members influences the quality of family relationships and family functioning, it becomes crucial for family scientists to determine and understand the mechanisms underlying these associations. An empirical resource…

The Needs of Families: Results of a Statewide Survey in Massachusetts.

ERIC Educational Resources Information Center

Agosta, John M.; And Others

The report presents findings from a survey of 243 caregiving families in Massachusetts which explored family needs and characteristics, as well as those of their developmentally disabled family members. Survey questions focused on family information, characteristics of the disabled family member, information on family needs, care-related costs…

Positive Family Functioning.

ERIC Educational Resources Information Center

Sussman, Marvin B.

The persistence of the nuclear family as the primary social unit in the United States and most all other societies, especially complex ones, is a fact. Values shape the definition of family, especially the "good family," and the "great debate" of this period on family failure, family corruption and the family's near demise originates in…

Today's Changing Families and their Needs.

ERIC Educational Resources Information Center

Thierman, Susan B.

This paper discusses the changing concept of the American family, identifying four major trends in family structure: (1) a dramatic increase in two-wage-earner families; (2) more working women; (3) more single-parent families; and (4) restructuring of families through divorces and remarriages. The family has been losing many of its traditional…

Patient-centered family meetings in palliative care: a quality improvement project to explore a new model of family meetings with patients and families at the end of life.

PubMed

Sanderson, Christine R; Cahill, Philippa J; Phillips, Jane L; Johnson, Anne; Lobb, Elizabeth A

2017-12-01

Family meetings in palliative care can enhance communication with family members and identify unmet needs. However, the patient's voice may not be heard. This pre and post-test quality improvement project was conducted from 2013-2014 and investigated a patient-centered family meeting, which is a different approach to palliative care family meetings, to determine its feasibility and acceptability for patients, family and the palliative care team. Newly admitted patients to an Australian in-patient specialist palliative care unit were invited to ask anyone they wished to join them in a meeting with the palliative care team and to identify issues they wished to discuss. Consenting inpatients were interviewed shortly after admission; participated in a family meeting and re-interviewed 2-3 days after the meeting. Family members provided feedback at the end of the meeting. A focus group was held with staff for feedback on this new approach for family meetings. Meetings were observed, documented and thematically analyzed. Thirty-one newly admitted patients were approached to participate in a family meeting. Eighty-four percent had family meetings and the majority (96%) was attended by the patient. Thematic analysis revealed 69% of patient-centered meetings raised end-of-life concerns and 54% were "family-focused". Patient-centered family meetings in palliative care were shown to be feasible and acceptable for staff, patients and family members. Many patients and families spontaneously shared end-of-life concerns. A patient-centered approach to family meetings that includes active patient involvement may provide additional and valued opportunities for patients and families to: express mutual concerns, deliver messages of comfort and appreciation, and prepare for death. Further investigation of this approach, including families' bereavement outcomes, is warranted.

Preferences for family involvement in care among consumers with serious mental illness.

PubMed

Cohen, Amy N; Drapalski, Amy L; Glynn, Shirley M; Medoff, Deborah; Fang, Li Juan; Dixon, Lisa B

2013-03-01

Despite robust evidence of efficacy, family services for individuals diagnosed as having serious mental illness are of limited availability and drastically underutilized. This underutilization may be due to a mismatch between consumer and family preferences and the services offered. This study is the first systematic report on preferences expressed by consumers with serious mental illness for family involvement. The study enrolled 232 mental health consumers with serious mental illness who had contact with family but did not have any family regularly involved in their mental health care. Consumers were recruited from outpatient mental health clinics at three large medical centers in two Veterans Integrated Service Networks. Interviews elicited demographic characteristics, treatment preferences regarding family involvement, and perceived benefits and barriers to involvement. Chart diagnoses and measures of symptom severity, family functioning, and contact were collected. Seventy-eight percent (171 of 219) of the consumers wanted family members to be involved in their care, and many desired involvement through several methods. Consumers were concerned with the impact of involvement on both themselves and their family member. The consumer's degree of perceived benefit of family involvement significantly predicted the degree of desire for family involvement after analyses controlled for service need (family conflict, family-related quality of life, and symptom severity), enabling factors (family contact and family capacity), demographic variables (age, gender, race, living with family, and marital status), and barriers perceived by the consumer. The extent of overall support for family involvement in care coupled with the heterogeneity of preferred modes and concerns and anticipated benefits underscore the imperative to offer diverse family services and to elicit consumers' preferences regarding whether and how to involve their families.

Family Relationships and Psychosocial Dysfunction Among Family Caregivers of Patients With Advanced Cancer.

PubMed

Nissen, Kathrine G; Trevino, Kelly; Lange, Theis; Prigerson, Holly G

2016-12-01

Caring for a family member with advanced cancer strains family caregivers. Classification of family types has been shown to identify patients at risk of poor psychosocial function. However, little is known about how family relationships affect caregiver psychosocial function. To investigate family types identified by a cluster analysis and to examine the reproducibility of cluster analyses. We also sought to examine the relationship between family types and caregivers' psychosocial function. Data from 622 caregivers of advanced cancer patients (part of the Coping with Cancer Study) were analyzed using Gaussian Mixture Modeling as the primary method to identify family types based on the Family Relationship Index questionnaire. We then examined the relationship between family type and caregiver quality of life (Medical Outcome Survey Short Form), social support (Interpersonal Support Evaluation List), and perceived caregiver burden (Caregiving Burden Scale). Three family types emerged: low-expressive, detached, and supportive. Analyses of variance with post hoc comparisons showed that caregivers of detached and low-expressive family types experienced lower levels of quality of life and perceived social support in comparison to supportive family types. The study identified supportive, low-expressive, and detached family types among caregivers of advanced cancer patients. The supportive family type was associated with the best outcomes and detached with the worst. These findings indicate that family function is related to psychosocial function of caregivers of advanced cancer patients. Therefore, paying attention to family support and family members' ability to share feelings and manage conflicts may serve as an important tool to improve psychosocial function in families affected by cancer. Copyright © 2016 American Academy of Hospice and Palliative Medicine. All rights reserved.

Family dynamics in families with children with Attention Deficit Hyperactivity Disorder.

PubMed

Chu, Kangkang; Li, Shasha; Chen, Yixin; Wang, Mingchun

2012-10-01

Development of adjunctive family therapy for the treatment of children with Attention Deficit Hyperactivity Disorder (ADHD) in China requires a detailed understanding of the family dynamics of these families. Assess the family dynamics of families with children who have ADHD in Nanjing, China. Forty-six children 10 to 17 years of age treated at the Nanjing Brain Hospital for ADHD and 46 control children of the same age and gender from schools in Nanjing completed the 19-item Questionnaire of Systematic Family Dynamics (QSFD) which assesses four dimensions of family functioning: Family Atmosphere, Individuation, Moral Absolutism, and Personal Responsibility for Psychological Problems. There were no differences between groups in the perceived causes of psychological problems but the ADHD children reported a poorer family atmosphere, less independence from parents, and more ambiguity about 'right' and 'wrong' in the family. After adjustment for the potential confounding effects of parental education and family economic status, the findings of poorer family atmosphere and less individuation in the ADHD children remained statistically significant. The internal consistency of the four dimensions of the QSFD as completed by the children were poor (alpha=0.44-0.53). This preliminary study on the family dynamics of families with children that have ADHD finds that the ADHD children report a poor family atmosphere and little independence from parents. Further work is needed to validate the methods for assessing family dynamics in Chinese families, particularly when using children as informants, but this method provides valuable information that could be used as the focus of adjunctive family therapy to augment the traditional pharmacological and behavioral approaches to the treatment of ADHD.

Associations between TV Viewing at Family Meals and the Emotional Atmosphere of the Meal, Meal Healthfulness, Child Dietary Intake, and Child Weight Status

PubMed Central

Trofholz, Amanda C.; Tate, Allan D.; Miner, Michael H.; Berge, Jerica M.

2016-01-01

Background Research on family meals has demonstrated that family meals are protective for many aspects of child and adolescent health. It is unclear whether distractions at family meals, such as watching TV, are associated with child weight and weight-related behaviors, the emotional atmosphere at the meal, or family meal healthfulness. Methods Direct observational and objective data were collected on primarily low-income and minority families (n=120) with 6–12 year old children. Data were collected during home visits and included 24-hr dietary recalls, anthropometry, and video-recorded family meals. Video-recorded family meals were coded to assess the presence of TV, whether the family was paying attention to the TV, family group enjoyment and the dietary healthfulness of the foods served at family meals. Results The presence of TV was negatively associated with the dietary healthfulness and emotional atmosphere of the meal and the child’s overall dietary quality. It was positively associated with serving fast food for family meals. Those families who were paying attention to the TV had significantly worse meal dietary healthfulness and were more likely to have fast food at family meals compared to those who were not paying attention. No significant findings were found between the presence of TV at family meals and child overweight status. Conclusions Study results show that TV is frequently present at family meals. Even if families are not paying attention to the TV, it appears that simply having the TV on as background noise is associated with deleterious outcomes. In addition to increasing family meals, families should be given guidance on turning off the TV and making the family meal a time to connect with one another. PMID:27756638

The effects of family structure and function on mental health during China's transition: a cross-sectional analysis.

PubMed

Cheng, Yao; Zhang, Liuyi; Wang, Fang; Zhang, Ping; Ye, Beizhu; Liang, Yuan

2017-05-05

Social change, intensified by industrialization and globalization, has not only changed people's work lives but also their personal lives, especially in developing countries. The aim of this study was to provide evidence and recommendations regarding family structure, function, and mental health to actively respond to rapid social change. A cross-sectional survey was conducted face-to-face and door-to-door from July 2011 to September 2012 in Hubei Province, central China. Family structure comprised alone, couple, nuclear family, and extended family; family function was measured using the family APGAR (Adaptation, Partnership, Growth, Affection, and Resolve) scale, and mental health was measured using the Chinese version of the 12-item General Health Questionnaire (GHQ-12). The urban-vs-rural difference of family structure among alone, couple, nuclear family, and extended family was statistically significant (5.21% vs 4.62%; 27.36% vs 13.14%; 33.22% vs 27.74%; 34.20% vs 54.50%, respectively; p < 0.0001); and those difference of family function was not statistically significant (8.11 ± 2.13 vs 8.09 ± 2.27, p = 0.9372). The general linear regression showed that the effect of family structure on mental health, whether urban or rural, was not significant, however, the effect of family function was significant, especially regarding better family functioning with better mental health. Combined the effects of family structure and function on mental health, the external form of family (family structure) may not be important; while the internal quality of role (family function) might be key. Improving the residents' family function would be a priority strategy for family practice with their mental health.

Associations between TV viewing at family meals and the emotional atmosphere of the meal, meal healthfulness, child dietary intake, and child weight status.

PubMed

Trofholz, Amanda C; Tate, Allan D; Miner, Michael H; Berge, Jerica M

2017-01-01

Research on family meals has demonstrated that family meals are protective for many aspects of child and adolescent health. It is unclear whether distractions at family meals, such as watching TV, are associated with child weight and weight-related behaviors, the emotional atmosphere at the meal, or family meal healthfulness. Direct observational and objective data were collected on primarily low-income and minority families (n = 120) with 6-12 year old children. Data were collected during home visits and included 24-hr dietary recalls, anthropometry, and video-recorded family meals. Video-recorded family meals were coded to assess the presence of TV, whether the family was paying attention to the TV, family group enjoyment and the dietary healthfulness of the foods served at family meals. The presence of TV was negatively associated with the dietary healthfulness and emotional atmosphere of the meal and the child's overall dietary quality. It was positively associated with serving fast food for family meals. Those families who were paying attention to the TV had significantly worse meal dietary healthfulness and were more likely to have fast food at family meals compared to those who were not paying attention. No significant findings were found between the presence of TV at family meals and child overweight status. Study results show that TV is frequently present at family meals. Even if families are not paying attention to the TV, it appears that simply having the TV on as background noise is associated with deleterious outcomes. In addition to increasing family meals, families should be given guidance on turning off the TV and making the family meal a time to connect with one another. Copyright © 2016 Elsevier Ltd. All rights reserved.

Family dynamics in families with children with Attention Deficit Hyperactivity Disorder

PubMed Central

Chu, Kangkang; Li, Shasha; Chen, Yixin; Wang, Mingchun

2012-01-01

Background Development of adjunctive family therapy for the treatment of children with Attention Deficit Hyperactivity Disorder (ADHD) in China requires a detailed understanding of the family dynamics of these families. Aim Assess the family dynamics of families with children who have ADHD in Nanjing, China. Methods Forty-six children 10 to 17 years of age treated at the Nanjing Brain Hospital for ADHD and 46 control children of the same age and gender from schools in Nanjing completed the 19-item Questionnaire of Systematic Family Dynamics (QSFD) which assesses four dimensions of family functioning: Family Atmosphere, Individuation, Moral Absolutism, and Personal Responsibility for Psychological Problems. Results There were no differences between groups in the perceived causes of psychological problems but the ADHD children reported a poorer family atmosphere, less independence from parents, and more ambiguity about ‘right’ and ‘wrong’ in the family. After adjustment for the potential confounding effects of parental education and family economic status, the findings of poorer family atmosphere and less individuation in the ADHD children remained statistically significant. The internal consistency of the four dimensions of the QSFD as completed by the children were poor (alpha=0.44-0.53). Conclusion This preliminary study on the family dynamics of families with children that have ADHD finds that the ADHD children report a poor family atmosphere and little independence from parents. Further work is needed to validate the methods for assessing family dynamics in Chinese families, particularly when using children as informants, but this method provides valuable information that could be used as the focus of adjunctive family therapy to augment the traditional pharmacological and behavioral approaches to the treatment of ADHD. PMID:25328351

Development and testing of the Survey of Family Environment (SFE): a novel instrument to measure family functioning and needs for family support.

PubMed

Hohashi, Naohiro; Honda, Junko

2012-01-01

Hohashi's Concentric Sphere Family Environment Model (CSFEM; Hohashi & Honda, 2011) is a newly proposed family nursing theory for holistically understanding the family environment that acts on family well-being. The purpose of this article is to develop and psychometrically test the Japanese version of the Survey of Family Environment (SFE-J), grounded in the CSFEM, for measuring family's perceived family functioning and family's perceived needs for family support. The SFE-J is a 30-item self-administered instrument that assesses five domains (suprasystem, macrosystem, microsystem, family internal environment system, and chronosystem) and has been subjected to rigorous reliability and validity investigations among paired partners in child-rearing families (N of family = 1,990). Internal consistency reliability was high as measured by Cronbach's alpha coefficients. Temporal stability over a 2-week interval was supported by high (substantial or perfect) and significant intraclass correlation coefficients. The total score for the SFE-J was significantly correlated with the Japanese version of the Feetham Family Functioning Survey (FFFS-J), indicating an acceptable concurrent validity. Construct validity was supported by a confirmatory factor analysis that evaluated the five-factor structure to measure the concept of CSFEM. Results also demonstrate that the SFE-J family functioning scores show no significant differences between paired partners. The SFE-J is a reliable and valid instrument to assess not only intrafamily functioning but also interfamily functioning and, by identifying items/domains with high requirements for family support, serves to facilitate the providing of appropriate support to families.

Childhood Obesity and Interpersonal Dynamics During Family Meals

PubMed Central

Rowley, Seth; Trofholz, Amanda; Hanson, Carrie; Rueter, Martha; MacLehose, Richard F.; Neumark-Sztainer, Dianne

2014-01-01

BACKGROUND: Family meals have been found to be associated with a number of health benefits for children; however, associations with obesity have been less consistent, which raises questions about the specific characteristics of family meals that may be protective against childhood obesity. The current study examined associations between interpersonal and food-related family dynamics at family meals and childhood obesity status. METHODS: The current mixed-methods, cross-sectional study included 120 children (47% girls; mean age: 9 years) and parents (92% women; mean age: 35 years) from low-income and minority communities. Families participated in an 8-day direct observational study in which family meals were video-recorded in their homes. Family meal characteristics (eg, length of the meal, types of foods served) were described and associations between dyadic (eg, parent-child, child-sibling) and family-level interpersonal and food-related dynamics (eg, communication, affect management, parental food control) during family meals and child weight status were examined. RESULTS: Significant associations were found between positive family- and parent-level interpersonal dynamics (ie, warmth, group enjoyment, parental positive reinforcement) at family meals and reduced risk of childhood overweight. In addition, significant associations were found between positive family- and parent-level food-related dynamics (ie, food warmth, food communication, parental food positive reinforcement) and reduced risk of childhood obesity. CONCLUSIONS: Results extend previous findings on family meals by providing a better understanding of interpersonal and food-related family dynamics at family meals by childhood weight status. Findings suggest the importance of working with families to improve the dyadic and family-level interpersonal and food-related dynamics at family meals. PMID:25311603

Adopted Children and Discipline

MedlinePlus

... Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care Communication & Discipline Types of Families Media Work & ... Community Healthy Children > Family Life > Family Dynamics > Adoption & Foster Care > Adopted Children & Discipline Family Life Listen Español ...

Comparison of Families with and without a Suicide Prevention Plan Following a Suicidal Attempt by a Family Member

PubMed Central

Cho, Heung-Don; Kim, Nam-Young; Gil, Hyo-wook; Jeong, Du-shin

2015-01-01

The frequency and extent of the existence of a familial suicide prevention plan may differ across cultures. The aim of this work was, therefore, to determine how common it was for families to develop a suicide prevention plan and to compare the main measures used by families with and without such a plan, after an attempt to commit suicide was made by a member of a family living in a rural area of Korea. On the basis of the presence or absence of a familial suicide prevention plan, we compared 50 recruited families that were divided into 2 groups, with Group A (31 families) employing a familial suicide prevention plan after a suicide attempt by a family member, and Group B (19 families) not doing so. The strategy that was employed most frequently to prevent a reoccurrence among both populations was promoting communication among family members, followed by seeking psychological counseling and/or psychiatric treatment. Contrary to our expectation, the economic burden from medical treatment after a suicide attempt did not influence the establishment of a familial suicide prevention plan. It is a pressing social issue that 38% (19 of 50) of families in this study did not employ a familial suicide prevention plan, even after a family member had attempted suicide. Regional suicide prevention centers and/or health authorities should pay particular attention to these patients and their families. PMID:26130963

Comparison of Families with and without a Suicide Prevention Plan Following a Suicidal Attempt by a Family Member.

PubMed

Cho, Heung-Don; Kim, Nam-Young; Gil, Hyo-wook; Jeong, Du-shin; Hong, Sae-yong

2015-07-01

The frequency and extent of the existence of a familial suicide prevention plan may differ across cultures. The aim of this work was, therefore, to determine how common it was for families to develop a suicide prevention plan and to compare the main measures used by families with and without such a plan, after an attempt to commit suicide was made by a member of a family living in a rural area of Korea. On the basis of the presence or absence of a familial suicide prevention plan, we compared 50 recruited families that were divided into 2 groups, with Group A (31 families) employing a familial suicide prevention plan after a suicide attempt by a family member, and Group B (19 families) not doing so. The strategy that was employed most frequently to prevent a reoccurrence among both populations was promoting communication among family members, followed by seeking psychological counseling and/or psychiatric treatment. Contrary to our expectation, the economic burden from medical treatment after a suicide attempt did not influence the establishment of a familial suicide prevention plan. It is a pressing social issue that 38% (19 of 50) of families in this study did not employ a familial suicide prevention plan, even after a family member had attempted suicide. Regional suicide prevention centers and/or health authorities should pay particular attention to these patients and their families.

Predicting resident confidence to lead family meetings.

PubMed

Butler, D J; Holloway, R L; Gottlieb, M

1998-05-01

Family physicians frequently encounter patients' family members in family meetings regarding health care. Although residents are expected to learn how to interview families, no quantitative studies have examined variables associated with building residents' confidence in their ability to lead family meetings. The current study sought to clarify the relationship between a number of training, participant, and situational components and resident confidence. All family practice residents (n = 90) in a five-residency program system were sent a survey that examined their experience in and perceived competence to conduct family meetings. Responses were analyzed with a hierarchical regression analysis and an ex post facto univariate analysis. Residents with higher perceived confidence in their ability to run a family meeting were male, had specific training for leading family meetings, had participated in and initiated more family meetings, perceived stronger family physician faculty support, and had more family systems training than lower-confidence residents. The results highlight the experiential, curricular, and environmental variables that are associated with building resident confidence to lead family meetings. Residents may benefit from early exposure to the skills needed for family meetings and from reinforcement of these skills through observations of skilled practitioners, the expectation that they will initiate meetings, and the opportunity to debrief meetings with supportive faculty. Family meeting curricula should include conflict management skills and incorporate input from other specialists and hospital personnel who meet with families.

Relationship between family quality of life and day occupations of young people with Down syndrome.

PubMed

Foley, Kitty-Rose; Girdler, Sonya; Downs, Jenny; Jacoby, Peter; Bourke, Jenny; Lennox, Nick; Einfeld, Stewart; Llewellyn, Gwynnyth; Parmenter, Trevor R; Leonard, Helen

2014-09-01

To explore relationships between family quality of life, day occupations and activities of daily living (ADL) of young persons with Down syndrome. Data were collected from 150 families with a young person with Down syndrome aged 16-30 years participating in the Down syndrome "Needs Opinions Wishes" database. Data described the young person's characteristics (including functional abilities, behaviour and day occupations) and family characteristics (including income, family and community supports and quality of life). Compared to families of young people attending open employment, families of young people participating in sheltered employment tended to report poorer family quality of life, after adjusting for personal characteristics, behaviour and income (coeff -6.78, 95 % CI -14.38, 0.81). Family supports reduced this relationship (coeff -6.00, 95 % CI -12.76, 0.76). Families of young people with greater functioning in ADL reported better family quality of life regardless of personal and environmental factors (coeff 0.45, 95 % CI 0.05, 0.85) and inclusion of family factors such as family supports reduced this association (coeff 0.29, 95 % CI -0.10, 0.67). Participation of young people with Down syndrome in open employment may positively influence family quality of life. Services that facilitate functioning in ADL and assist the families in accessing suitable family supports have the potential to positively influence family quality of life.

Work-family fit: the impact of emergency medical services work on the family system.

PubMed

Roth, Sheila Gillespie; Moore, Crystal Dea

2009-01-01

The stress associated with a career in emergency medical services (EMS) can impact the work-family fit and function of the family system for EMS personnel. Little research has been conducted on how the demands associated with a career in EMS influences family life. Objective. To describe salient EMS work factors that can impact the family system. Twelve family members (11 spouses and one parent) of EMS workers were interviewed using a semistructured qualitative interview guide that explored issues related to their family members' work that could impact the quality of family life. Using a phenomenological approach, transcribed interview data were examined for themes that illuminated factors that influence work-family fit. Data analysis revealed that shift work impacts numerous aspects of family life, including marital and parental roles, leisure and social opportunities, and home schedules and rhythms. Furthermore, families coped with challenges associated with their loved one's EMS work through negotiating role responsibilities, developing their own interests, giving their family member "space," and providing support by listening and helping the EMS worker process his or her reactions to difficult work. In addition, family members reported concern over their EMS worker's physical safety. Implications from the data are discussed vis-a-vis the work-family fit and family systems models. Education, communication, support systems, and individual interests are key ways to promote a healthy work-family fit.

Family functioning, burden and parenting stress 2 years after very preterm birth.

PubMed

Treyvaud, Karli; Doyle, Lex W; Lee, Katherine J; Roberts, Gehan; Cheong, Jeanie L Y; Inder, Terrie E; Anderson, Peter J

2011-06-01

Examining rates of difficulties in family functioning following very preterm birth has been a relatively neglected area of research. To examine family functioning, burden and parenting stress in families with very preterm compared with term born children, and investigate influences of parental mental health problems and child neurodevelopmental disability on family outcomes in families with preterm children. Participants were 184 very preterm and 71 term children and their parents. Parents completed the Family Assessment Device, Parenting Stress Index and Impact on Family questionnaires when their children were 2 years old (corrected for prematurity). Parental mental health and social risk information were also collected. Children were assessed for neurodevelopmental disability. Families with very preterm children reported poorer family functioning (p=.03) compared with families with term born children, with less evidence for differences between families with very preterm and term born children in parenting stress and family burden. Within very preterm families, parental mental health problems were associated with higher levels of parenting stress (p=.001), and parents of children with a neurodevelopmental disability were more likely to report higher family burden (p=.04). For families with very preterm children, parental mental health symptoms and child neurodevelopmental disability may identify families at risk of greater stress and burden who may benefit from additional support. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Identifying factors related to family management during the coping process of families with childhood chronic conditions: a multi-site study.

PubMed

Zhang, Ying; Wei, Min; Shen, Nanping; Zhang, Yaqing

2015-01-01

This study was designed to determine the key predictors for each aspect of family management of families with children who have chronic conditions in China. The participants included 399 caregivers whose children have chronic illnesses. We used the following instruments: Child Behavior Checklist; Feetham Family Functioning Survey; and Family Management Measures. The final modes of the hierarchical regression explained 29-48% of the variance in aspects of family management. More family support should be provided for those with low family income, children with renal and genetic disorders and rheumatic diseases and those living in rural areas. Child and family functioning affects family management. Copyright © 2015 Elsevier Inc. All rights reserved.

Is work-family balance more than conflict and enrichment?

PubMed

Carlson, Dawn S; Grzywacz, Joseph G; Zivnuska, Suzanne

2009-10-01

This study deepens our theoretical and practical understanding of work-family balance, defined as the 'accomplishment of role-related expectations that are negotiated and shared between an individual and his/her role-related partners in the work and family domains' (Grzywacz & Carlson, 2007: 458). We develop a new measure of work-family balance and establish discriminant validity between it, work-family conflict, and work-family enrichment. Further, we examine the relationship of work-family balance with six key work and family outcomes. Results suggest that balance explains variance beyond that explained by traditional measures of conflict and enrichment for five of six outcomes tested: job satisfaction, organizational commitment, family satisfaction, family performance, and family functioning. We conclude with a discussion of the applications of our work.

Family Smoking, Exposure to Secondhand Smoke at Home and Family Unhappiness in Children

PubMed Central

Chen, Jian Jiu; Ho, Sai Yin; Au, Wing Man; Wang, Man Ping; Lam, Tai Hing

2015-01-01

Tobacco use adversely affects many aspects of well-being and is disliked by non-smokers. However, its association with family happiness is unknown. We investigated the associations of family unhappiness with smoking in family members and secondhand smoke (SHS) exposure at home in Hong Kong children. In a school-based survey in 2012–2013, 1238 primary school students (mean age 8.5 years, standard deviation 0.9; 42.6% boys) reported family smoking, SHS exposure at home and whether their families had any unpleasant experience caused by smoking or SHS in the past 30 days (tobacco-related unpleasant experience), and rated the overall level of happiness in their families (family unhappiness). Multivariable logistic regression was used to study the associations of tobacco-related unpleasant experience and family unhappiness with family smoking and SHS exposure at home. Tobacco-related unpleasant experience and family unhappiness were reported by 27.5% and 16.5% of students. Unpleasant experience was more strongly associated with family smoking than SHS exposure at home. Family unhappiness was associated with both family smoking (odds ratio 2.37; 95% confidence interval 1.51–3.71) and SHS exposure at home (1.82; 1.39–2.40). These results suggest a previously neglected possible impact of tobacco use on family happiness. PMID:26580642

Psychological health of military children: Longitudinal evaluation of a family-centered prevention program to enhance family resilience

PubMed Central

Lester, Patricia; Stein, Judith A.; Saltzman, William; Woodward, Kirsten; MacDermid, Shelley W.; Milburn, Norweeta; Mogil, Catherine; Beardslee, William

2014-01-01

Family-centered preventive interventions have been proposed as relevant to mitigating psychological health risk and promoting resilience in military families facing wartime deployment and reintegration. This study evaluates the impact of a family-centered prevention program, Families OverComing Under Stress Family Resilience Training (FOCUS), on the psychological adjustment of military children. Two primary goals include: 1) Understanding the relationships of distress among family members using a longitudinal path model to assess relations at the child and family level, and 2) Determining pathways of program impact on child adjustment. Multilevel data analysis using structural equation modeling was conducted with de-identified service delivery data from 280 families (505 children ages 3-17) in two follow-up assessments. Standardized measures included Service Member and Civilian parental distress (Brief Symptom Inventory, PTSD Checklist – Military), child adjustment (Strengths and Difficulties Questionnaire), and family functioning (McMaster Family Assessment Device). Distress was significantly related among the service member parent, civilian parent and children. FOCUS improved family functioning, which in turn significantly reduced child distress at follow-up. Salient components of improved family functioning in reducing child distress mirrored resilience processes targeted by FOCUS. These findings underscore the public health potential of family-centered prevention for military families, and suggest areas for future research. PMID:23929043

Pathways between profiles of family functioning, child security in the interparental subsystem, and child psychological problems.

PubMed

Davies, Patrick T; Cummings, E Mark; Winter, Marcia A

2004-01-01

This study was designed to delineate pathways between systems profiles of family functioning, children's emotional insecurity in the interparental relationship, and their psychological adjustment in a sample of 221 children and their parents. Consistent with family systems theory, cluster analyses conducted with assessments of marital, coparental, and parent-child functioning indicated that families fit into one of four profiles: (a) cohesive families, characterized by warmth, affection, and flexible well-defined boundaries in family relationships; (b) disengaged families, reflected in high levels of adversity and low levels of support across family subsystems; (c) enmeshed families, evidenced by high levels of discord and weak maintenance of relationship boundaries in the family unit; and (d) adequate families, defined by elevated parental psychological control within a larger family context of low discord and high warmth. In comparison to children in cohesive families, children in enmeshed and disengaged families exhibited greater signs of insecurity in the interparental relationship concurrently and internalizing and externalizing symptoms both concurrently and 1 year later. Structural equation models revealed that a latent, multimethod measure of insecurity in the interparental relationship partially mediated associations between family enmeshment and disengagement and children's psychological symptoms 1 year later. Results are discussed in relation to how they inform and refine a family-wide model of the emotional security hypothesis.

Parent Perceptions of Family Social Supports in Families With Children With Epilepsy.

PubMed

Decker, Kim A; Miller, Wendy R; Buelow, Janice M

2016-12-01

When a child is diagnosed with epilepsy, not only has the child's life been disrupted but also the family's sense of normalcy. Although there is considerable literature discussing family concerns and social support issues in families with chronically ill children, a major gap lies in the exploration of how the specifics of childhood epilepsy affect parents and family operations. The purpose of this study was to identify psychosocial care needs of parents of children with epilepsy. Utilizing the Family Systems Nursing theory as a framework, this correlation study examined the relationships among social and community support, family needs, family empowerment, and family quality of life in 29 primary caregivers of a child with epilepsy. These families felt highly supported; they had low needs and high perceptions of empowerment. There was a negative association between social supports and the total family needs survey scale and the subscales of financial support, help regarding explaining to others, and professional support. There was no association between family empowerment or quality of life with parental perceptions of social support. In general, as parental perceptions of family needs increased, perceptions of familial social supports decreased. Further research is recommended to investigate varying socioeconomic status effects in families with children with pediatric epilepsy.

Families and Education: An Educator's Resource for Family Involvement. (Revised Edition).

ERIC Educational Resources Information Center

App, Marie, Comp.; Grinde, Jane, Comp.

This handbook for educators offers guidance on ways to understand families, family-teacher communication, the process of reinforcing classwork at home, caring for the whole child, and selected resources. Chapter 1 discusses the climate for family involvement, different perceptions of teachers and families, what families want to know, today's…

Development of the Work-Family Interface Scale.

ERIC Educational Resources Information Center

Curbow, Barbara; McDonnell, Karen; Spratt, Kai; Griffin, Joan; Agnew, Jacqueline

2003-01-01

Developed and tested a 20-item measure of work-family interface with child care providers. Confirmed five factors: general overload, conflict of family to work, spillover of family to work, spillover of work to family, and conflict of work to family. Regression lines for low, medium, and high levels of work-family interface indicated that high…

A Descriptive Model of a Family Communiversity.

ERIC Educational Resources Information Center

Kohut, Nester C.

Family conservation is a new approach for strengthening nuclear families on a system level. The family communiversity is an agency developed to effect that approach. A discussion of family conservation on the systems level concerns the need for coping with those forces detrimental to families. The objective of family conservation is to maximize…

Psychologists and Families of the Severely Mentally Ill: The Role of Family Consultation.

ERIC Educational Resources Information Center

Bernheim, Kayla F.

1989-01-01

The needs of families of the mentally ill are being newly evaluated. While family burden remains a real concomitant of mental disorders, assistance from mental health professionals often falls short of family needs. Family consultation seeks to address these serious family problems. Issues for graduate psychology education are discussed. (AF)

Reclaiming Family Privilege

ERIC Educational Resources Information Center

Seita, John

2012-01-01

The pull for family is strong, almost primeval, most likely it is evolutionary, and for those lacking the benefit of family or Family Privilege, the loss of family is painful and profoundly sad. Young people who struggle to cope without stable family connections are profoundly aware of their lack of "Family Privilege." In this article, the author…

Examining Claims of Family Process Differences Ensuing from the Choice to Home-School

ERIC Educational Resources Information Center

Butler, Mark H.; Harper, James M.; Call, Matthew L.; Bird, Mark H.

2015-01-01

Advocates of home-schooling claim a variety of positive educational and familial outcomes. Research is needed to examine possible effects of home-schooling on family relationships. We investigated family environment differences between home-schooling and public-schooling families matched in terms of family-centric orientation. Family cohesion was…

Family Communication Standards: What Counts as Excellent Family Communication and How Are Such Standards Associated with Family Satisfaction?

ERIC Educational Resources Information Center

Caughlin, John P.

2003-01-01

Investigates the standards by which people judge communication in families. Presents three investigations that examine communication standards in family relationships. Suggests that both distressful ideals and unmet ideals are associated with family satisfaction. Notes that the results were consistent with the notion that family communication…

Family Physician Support for a Family With a Mentally Ill Member.

PubMed

McBride, J LeBron

2016-09-01

Mentally ill family members can have a formidable impact on the families in which they reside. Family physicians can intervene in powerful ways when they are sensitive to those who are mentally ill and their families and can provide much needed compassionate support. © 2016 Annals of Family Medicine, Inc.

Family losses following truncation selection in populations of half-sib families

Treesearch

J. H. Roberds; G. Namkoong; H. Kang

1980-01-01

Family losses during truncation selection may be sizable in populations of half-sib families. Substantial losses may occur even in populations containing little or no variation among families. Heavier losses will occur, however, under conditions of high heritability where there is considerable family variation. Standard deviations and therefore variances of family loss...

Family, Employment, and Individual Resource-Based Antecedents of Maternal Work-Family Enrichment from Infancy through Middle Childhood

PubMed Central

Zhou, Nan; Buehler, Cheryl

2015-01-01

This study used data from the NICHD Study of Early Child Care and Youth Development (N = 1,019) to examine family, employment, and individual antecedents of maternal work-family enrichment from infancy through middle childhood. Work-family conflict and important confounding factors were controlled. From the family domain, higher income-to-needs ratio and social support were associated with higher work-family enrichment. From the employment domain, greater job rewards, benefits of employment for children, and work commitment were associated with higher work-family enrichment. From the individual domain, higher maternal education and extroversion were associated with higher work-family enrichment. No family, employment, and individual characteristics were associated with work-family conflict across time except for partner intimacy. In general, the results supported antecedents of work-family enrichment that supply needed resources. The present study contributed to the literature by identifying antecedents of maternal work-family enrichment across early child developmental stages, which goes beyond examinations of particular life stages and a work-family conflict perspective. Implications for theory and practice are discussed. PMID:26641483

Influence and adaptability in families with deaf parents and hearing children.

PubMed

Rienzi, B M

1990-12-01

This study assessed the influence of individual family members in functional families, primarily to determine whether hearing children of deaf parents have more influence than do hearing children of hearing parents. Eight families with deaf parents and a hearing child and eight all hearing families were videotaped while planning a family meal together. It was found that deaf-parented families share many traits with hearing families. However, there were some differences. The hearing children of deaf parents had a greater number and percentage of their ideas accepted than did the hearing children of hearing parents. Differences were also noted between the deaf fathers and the hearing fathers. The deaf-parented families were more adaptable, as measured by the Family Adaptability and Cohesion Evaluation Scale. The observed difference in child influence, in and of itself, is neither good nor bad. Deafness of one family member, in an auditory dependent environment, may require a more flexible family power structure. Professionals assessing deaf-parented families should be sensitive to the special adaptive needs required for healthy functioning of the family.

Family-centered Care in the Outpatient General Psychiatry Clinic.

PubMed

Heru, Alison M

2015-09-01

Although family research supports family-centered care for all medical specialties, the benefit of family-centered care has not been fully realized in outpatient practice. Physicians, including psychiatrists, are not routinely taught how to work with families and may not be aware of the evidence-base for family interventions. However, some medical specialties, such as family medicine and palliative care, have a clinical practice that routinely includes the family. Clinicians working in medical clinics, such as diabetes clinics, know that successful management of chronic illness requires family involvement. Psychiatric clinics, such as The Family Center for Bipolar Disorder at Beth Israel Medical Center in New York City, also have a family-centered practice and show improved patient outcomes. This article provides guidelines, including clinical interview questions, to help psychiatrists practice family-centered care, either in a private office or in a general psychiatric outpatient clinic. The guidelines include questions that identify when to seek an in-depth family assessment or consultation. Family-centered care will become more useful when health care reimbursement focuses on patient outcome.

Out of the picture: a study of family drawings by children from step-, single-parent, and non-step families.

PubMed

Dunn, Judy; O'Connor, Thomas G; Levy, Irit

2002-12-01

Investigated the family drawings of 180 children ages 5 to 7 years in various family settings, including stepfather, single-parent, complex stepfamilies, and 2-parent control families. The relations of family type and biological relatedness to omission of family members and grouping of parents were examined. Children from step- and single-parent families were more likely to exclude family members than children from "control" non-step families, and exclusion was predicted from biological relatedness. Children who were biologically related to both resident parents were also more likely to group their parents together. Omission of family members was found to be associated with children's adjustment (specifically more externalizing and internalizing behavior) as reported by teachers and parents. The results indicate that biological relatedness is a salient aspect of very young children's representations of their families. The association between adjustment and exclusion of family members and grouping of parents indicates that family drawings may be useful research and clinical tools, when used in combination with other methods of assessment.

Family Management Style Framework: a new tool with potential to assess families who have children with brain tumors.

PubMed

Deatrick, Janet A; Thibodeaux, Annaka G; Mooney, Kim; Schmus, Cynthia; Pollack, Rosanna; Davey, Barbara Hieb

2006-01-01

Qualitative studies of families with children who have cancer or other serious illnesses have found that families often come to view their child and their lives as normal. They manage illness-related demands using family management styles that sustain usual patterns of family and child functioning. Few studies have addressed the family management styles of families who express less satisfaction with family and child functioning or who are identified by health care professionals as having difficulty with family functioning. Such families are likely to be overrepresented among those whose children are being treated for brain tumors that entail extremely burdensome treatments as well as a range of unfavorable prognoses and long-term sequelae. In fact, little is known about how these families manage on a day-to-day basis and how the interdisciplinary team can best provide supportive care to optimize their functioning. The purpose of this article is to present the Family Management Styles Framework as a tool that is useful in both clinical practice and research for assessing families who have children with cancer, including those with brain tumors.

Concordance Between Patient and Family Reports of Family Functioning in Bipolar I Disorder and Major Depressive Disorder

PubMed Central

Weinstock, Lauren M.; Wenze, Susan J.; Munroe, Mary K.; Miller, Ivan W.

2013-01-01

Despite the extensive literature on family functioning and mood disorders, less is known about concordance between patient- and family-reported family functioning. To address this question, adults with bipolar I disorder (BD; n = 92), major depressive disorder (MDD; n = 121), and their family members (ns = 135 and 201, respectively) were recruited from hospital sources. All patients and their family members completed the Family Assessment Device (Epstein et al., 1983). Intraclass correlation coefficients revealed that, in contrast to the moderate degree of concordance in the MDD sample, degree of concordance between patient- and family-reported family functioning was significantly weaker in BD. Subsequent analysis revealed that this discordance was driven by the reports of the child and young adolescent family members of the patients with BD. Results highlight the importance of collateral reports in the assessment of family functioning, especially among families of patients with BD, in research and treatment. PMID:23588224

Unfavourable family characteristics and their associations with childhood obesity: a cross-sectional study.

PubMed

Moens, Ellen; Braet, Caroline; Bosmans, Guy; Rosseel, Yves

2009-07-01

This cross-sectional study explores the influence of multiple familial factors on children's weight status and the interaction between parenting stress and unfavourable family characteristics. A total of 197 families with children between 6 and 14 years participated in this study. Of this group, 97 families had a child with normal weight and 100 families had a child with overweight. Parents reported on seven family factors (maternal BMI, number of children, family structure, socioeconomic position, life events, parental psychopathology and parenting stress). Families with overweight children experience more parenting stress. A regression analysis revealed that familial factors explain 27% in the variance in child's weight status. The hypothesis that a combination of familial factors will be more able to explain child's adiposity could not be confirmed. Familial factors have moderate ability to predict children's weight status. There is a need to identify other familial mechanisms taking into account developmental and temporal evolutions over the past decade. 2009 John Wiley & Sons, Ltd and Eating Disorders Association

Parenting approaches, family functionality, and internet addiction among Hong Kong adolescents.

PubMed

Wu, Cynthia Sau Ting; Wong, Ho Ting; Yu, Kin Fai; Fok, Ka Wing; Yeung, Sheung Man; Lam, Cheuk Ho; Liu, Ka Man

2016-08-18

Internet addiction (IA) among adolescents has become a global health problem, and public awareness of it is increasing. Many IA risk factors relate to parents and the family environment. This study examined the relationship between IA and parenting approaches and family functionality. A cross-sectional study was conducted with 2021 secondary students to identify the prevalence of IA and to explore the association between adolescent IA and familial variables, including parents' marital status, family income, family conflict, family functionality, and parenting approaches. The results revealed that 25.3 % of the adolescent respondents exhibited IA, and logistic regression positively predicted the IA of adolescents from divorced families, low-income families, families in which family conflict existed, and severely dysfunctional families. Interestingly, adolescents with restricted Internet use were almost 1.9 times more likely to have IA than those whose use was not restricted. Internet addiction is common among Chinese adolescents in Hong Kong, and family-based prevention strategies should be aligned with the risk factors of IA.

The family assessment device: an update.

PubMed

Mansfield, Abigail K; Keitner, Gabor I; Dealy, Jennifer

2015-03-01

The current study set out to describe family functioning scores of a contemporary community sample, using the Family Assessment Device (FAD), and to compare this to a currently help-seeking sample. The community sample consisted of 151 families who completed the FAD. The help-seeking sample consisted of 46 families who completed the FAD at their first family therapy appointment as part of their standard care at an outpatient family therapy clinic at an urban hospital. Findings suggest that FAD means from the contemporary community sample indicate satisfaction with family functioning, while FAD scores from the help-seeking sample indicate dissatisfaction with family functioning. In addition, the General Functioning scale of the FAD continues to correlate highly with all other FAD scales, except Behavior Control. The cut-off scores for the FAD indicating satisfaction or dissatisfaction by family members with their family functioning continue to be relevant and the FAD continues to be a useful tool to assess family functioning in both clinical and research contexts. © 2014 Family Process Institute.

Family-centered end-of-life care in the ICU.

PubMed

Wiegand, Debra L; Grant, Marian S; Cheon, Jooyoung; Gergis, Mary A

2013-08-01

Families of older adults are intricately involved in the end-of-life decision-making process for a family member with a serious illness in the intensive care unit (ICU) setting. However, families are not always as involved and as informed as they would like to be. Creating a culture that assesses family needs and supports families is an important component of family-centered care. There are several strategies that nurses and other members of the interdisciplinary team can use to promote family-centered end-of-life care in the ICU. Nurses can get to know the family by spending time talking with them, assessing them, seeking to understand their perspectives on their family member's condition, and discussing previously verbalized patient wishes for care. This article offers strategies nurses can use to help guide the family through the end-of-life decision-making process, support families as difficult and complex decisions are made in collaboration with the health care team, and prepare families for the dying process. Copyright 2013, SLACK Incorporated.

Antecedents and outcomes of a fourfold taxonomy of work-family balance in Chinese employed parents.

PubMed

Lu, Jia-Fang; Siu, Oi-Ling; Spector, Paul E; Shi, Kan

2009-04-01

The study provided validity evidence for a fourfold taxonomy of work-family balance that comprises direction of influence (work to family vs. family to work) and types of effect (work-family conflict vs. work-family facilitation). Data were collected from 189 employed parents in China. The results obtained from a confirmatory factor analysis supported the factorial validity of the fourfold taxonomy of work-family balance with a Chinese sample. Child care responsibilities, working hours, monthly salary, and organizational family-friendly policy were positively related to the conflict component of work-family balance; whereas new parental experience, spouse support, family-friendly supervisors and coworkers had significant positive effects on the facilitation component of work-family balance. In comparison with the inconsistent effects of work-family conflict, work to family facilitation had consistent positive effects on work and life attitudes. The implications of findings in relation to China and other countries are discussed in the paper.

Concordance between patient and family reports of family functioning in bipolar I disorder and major depressive disorder.

PubMed

Weinstock, Lauren M; Wenze, Susan J; Munroe, Mary K; Miller, Ivan W

2013-05-01

Despite the extensive literature on family functioning and mood disorders, less is known about concordance between patient- and family-reported family functioning. To address this question, adults with bipolar I disorder (BD; n = 92) or major depressive disorder (MDD; n = 121) and their family members (n = 135 and 201, respectively) were recruited from hospital sources. All patients and their family members completed the Family Assessment Device (Epstein, Baldwin, Bishop. J Marital Fam Ther. 9:171-180, 1983). Intraclass correlation coefficients revealed that, in contrast to the moderate degree of concordance in the MDD sample, degree of concordance between patient- and family-reported family functioning was significantly weaker in BD. Subsequent analysis revealed that this discordance was driven by the reports of the child and young adolescent family members of the patients with BD. Results highlight the importance of collateral reports in the assessment of family functioning, especially among families of patients with BD, in research and treatment.

Liminality and low-income aging families by choice: meanings of family and support.

PubMed

McDaniel, Susan; Gazso, Amber

2014-12-01

Through the lens of individualization, aging families demonstrate changes both in family composition and in meanings of family and support. So, also, do low-income families that - in order to survive - choose flexible, sometimes novel, social-support relations, including kin and non-kin: these are aging families by choice. Applying the concept of liminality (transitional states of being) created through individualization, we explored the experiences of close relations in low-income families consisting of aging kin and non-kin members. Qualitative interviews with respondents representing two or three generations of aging families of choice illustrated how these families perceive the meanings of family and social support. We find that reciprocity is less vital to relationships of older with younger members in familial networks than may be expected. Liminality contours meanings and exchanges in low-income aging families of choice such that no matter how tenuous relations may be, they provide a sense of belonging and meaning.

Use of the Family Interaction Macro-coding System with Families of Adolescents: Psychometric Properties Among Pediatric and Healthy Populations

PubMed Central

Zebracki, Kathy; Kichler, Jessica C.; Fitzgerald, Christopher J.; Neff Greenley, Rachel; Alemzadeh, Ramin; Holmbeck, Grayson N.

2011-01-01

Objective To examine reliability and validity data for the Family Interaction Macro-coding System (FIMS) with adolescents with spina bifida (SB), adolescents with type 1 diabetes mellitus (T1DM), and healthy adolescents and their families. Methods Sixty-eight families of children with SB, 58 families of adolescents with T1DM, and 68 families in a healthy comparison group completed family interaction tasks and self-report questionnaires. Trained coders rated family interactions using the FIMS. Results Acceptable interrater and scale reliabilities were obtained for FIMS items and subscales. Observed FIMS parental acceptance, parental behavioral control, parental psychological control, family cohesion, and family conflict scores demonstrated convergent validity with conceptually similar self-report measures. Conclusions Preliminary evidence supports the use of the FIMS with families of youths with SB and T1DM and healthy youths. Future research on overall family functioning may be enhanced by use of the FIMS. PMID:21097956

Digital Inequalities of Family Life Information Seeking and Family Well-Being Among Chinese Adults in Hong Kong: A Population Survey

PubMed Central

2014-01-01

Background Inequalities in Internet use and health information seeking are well documented, but less is known about information for family life activities. Objective We investigated the social determinants of online family life information seeking behaviors and its associations with family well-being among Chinese adults in Hong Kong. Methods A probability-based telephone survey was conducted in 2012 to record family life information seeking behaviors, including frequency of seeking and paying attention to family life information, levels of trust, and perceived usefulness of family life information. Family well-being was assessed using 3 single items on perceived family harmony, happiness, and health, with higher scores indicating greater well-being. Adjusted odds ratios for family life information seeking behaviors by socioeconomic characteristics and lifestyle behaviors, and adjusted beta coefficients for family well-being by family life information seeking behaviors were calculated. Results Of 1537 respondents, 57.57% (855/1537) had ever and 26.45% (407/1537) sought monthly family life information through the Internet. Lower educational attainment and household income, smoking, and physical inactivity were associated with less frequent seeking and paying attention (all P<.05). Greater perceived family health was associated with more frequent attention (adjusted β=.32, 95% CI.11-.52), greater levels of trust (adjusted β=.28, 95% CI .07-.48), and perceived usefulness (adjusted β=.23, 95% CI .01-.45) of family life information. Frequent attention and higher level of trust were also associated with greater family harmony (adjusted β=.22, 95% CI .002-.41) and happiness (adjusted β=.23, 95% CI .003-.42), respectively. Conclusions This is the first study investigating family life information seeking behaviors and suggested inequalities of online family life information seeking behaviors. The association between family life information seeking behavior and family well-being needs to be confirmed in prospective studies. PMID:25281831

A family nursing educational intervention supports nurses and families in an adult intensive care unit.

PubMed

Eggenberger, Sandra K; Sanders, Marita

2016-11-01

The family experience of critical illness is filled with distress that may have a lasting impact on family coping and family health. A nurse can become a source of comfort that helps the family endure. Yet, nurses often report a lack of confidence in communicating with families and families report troubling relationships with nurses. In spite of strong evidence supporting nursing practice focused on the family, family nursing interventions often not implemented in the critical care setting. This pilot study examined the influence of an educational intervention on nurses' attitudes towards and confidence in providing family care, as well as families' perceptions of support from nurses in an adult critical care setting. An academic-clinical practice partnership used digital storytelling as an educational strategy. A Knowledge to Action Process Framework guided this study. Results of pre-intervention data collection from families and nurses were used to inform the educational intervention. A convenience sample of family members completed the Iceland Family Perceived Support Questionnaire (ICE-FPSQ) to measure perception of support provided by nurses. Video, voice, and narrative stories of nurses describing their experiences caring for family members during a critical illness and family members' experiences with a critically ill family member also guided education plans. When comparing the pre and post results of the Family Nurse Practice Scale (FNPS), nurses reported increased confidence, knowledge, and skill following the educational intervention. Qualitative data from nurses reported satisfaction with the educational intervention. Findings suggest that engaging nurses in educational opportunities focused on families while using storytelling methods encourages empathic understandings. Academic-clinician teams that drive directions show promise in supporting families and nurses in critical care settings. Plans are moving forward to use this study design and methods in other critical care settings. Copyright © 2016 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.

The change of family size and structure in China.

PubMed

1992-04-01

With the socioeconomic development and change of people's values, there is some significant change in family size and structure in China. According to the 10% sample data from the 4th Census, 1 family has 3.97 persons on an average, less than the 3rd Census by 0.44 persons; among all types of families, 1-generation families account for 13.5%, 3 generation families for 18.5%, and 2-generation families account for 68%. Instead of large families consisting of several generations and many members, small families has now become a principal family type in China. According to the analysis of the sample data from the 4th Census, the family size is mainly decided by the fertility level in particular regions, and it also depends on the economic development. So family size is usually smaller in more developed regions, such as in Beijing, Tianjin, Zhejiang, Liaoning as well as in Shanghai of which family size is only 3.08 persons; and family size is generally larger in less developed regions such as in Qinghai, Guangxi, Gansu, Xinjiang, and in Tibet of which family size is as large as 5.13 persons. Specialists regard the increase of the number of families as 1 of the major consequences of the economic development, change of living style, and improvement of living standard, Young people now are more inclined to live separately from their parents. However, the increase of the number of families will undoubtedly place more pressure on housing and require more furniture and other durable consumer goods from the market. Therefore, the government and other social sectors related should make corresponding plans and policies to cope with the increase of families and minifying of family size so as to promote family planning and socioeconomic development, and to create better social circumstances for small families. full text

Executing Military Family Programs in the New Fiscal Reality

DTIC Science & Technology

2013-03-01

these family programs to the Army’s Installation Management Command (IMCOM) G9, Family Moral Welfare and Recreation. IMCOM G9 refines policy and... Family Support Centers manages Navy Family Support Initiatives. 35F36 Additionally, to ensure that family needs are met, the Navy places family ...service members and their families . The 2008 DOD survey of active duty spouses concluded that managing childcare during deployment was a problem for 65

"Shared Destiny": The Dynamics of Relationships in Families of Patients With Brain Injury.

PubMed

Segev, Einav; Levinger, Miriam; Hochman, Yael

2018-01-01

This qualitative research focused on the relationships between family members of patients with acquired brain injury (ABI). The aim was to explore the dynamics between caregivers of the family member with a brain injury during rehabilitation hospitalization, and the relationships between them and the rest of the extended family. Twenty semistructured interviews were conducted with family members. In each family, the spouse of the patient and another family member involved in caregiving were interviewed. The importance of the relationships between family members during rehabilitation hospitalization justifies the examination undertaken in this research. Findings point at the change that took place in the relationships between family members because of the need to cope with a relative's injury. It is possible that direct intervention in the dynamics of the relationship, especially between the family of origin and the nuclear family of the injured person, can benefit extended families in coping with the crisis.

Maternal Employment Effects on Families and Preterm Infants at 18 Months

PubMed Central

YOUNGBLUT, JoANNE M.; LOVELAND-CHERRY, CAROL J.; HORAN, MARY

1994-01-01

The purposes of this study were to investigate the effects of maternal employment, maternal employment attitude/behavior consistency, and degree of choice and satisfaction with the employment decision on family functioning and preterm infant development and to describe changes in family functioning over time. Data were collected in the family’s home (N = 79) when the infant was 3, 9, and 18 months old. Parents in nonemployed-mother families were more satisfied with their families at 18 months than parents in employed-mother families. Decreases in family cohesion and/or adaptability from 9 to 18 months were seen for fathers in employed-mother families, for mothers in nonemployed-mother families, and for mothers in families where the mother’s employment attitudes and behaviors were consistent. Degree of choice was positively related to the child’s mental development, mother’s perception of family cohesion, and mother’s and father’s satisfaction with family. PMID:7971296

["And suddenly I have a tumor" - the situation of family S./N].

PubMed

Ries-Gisler, Tobias; Spirig, Rebecca

2014-04-01

Many families affected by a terminal illness need professional help and support. In order to be able to cope with emotional stress, loss of light-heartedness and changes in family structure thorough information is important for patients and their families. The Calgary Family-Assessment and Calgary Family Intervention-Model are suitable to determine the needs of concerned families and hence to offer appropriate interventions. In an instrumental case study the situation of Mrs. S.2 and her family was analyzed. Mrs. S. is suffering from an inoperable adenocarcinoma. An assessment classified the different information given during the first meeting and determined the focus of the interventions. Interventions concentrated on cognitive and emotional support. The case study showed how family models for nurses could systematically guide professionals in supporting families. Listening and spending time with the concerned person and their families showed to offer important factors, which were perceived as very helpful by the families.

The Nature of Family Engagement in Interventions for Children With Chronic Conditions.

PubMed

Knafl, Kathleen A; Havill, Nancy L; Leeman, Jennifer; Fleming, Louise; Crandell, Jamie L; Sandelowski, Margarete

2017-05-01

Recognizing the bi-directional relationship between family functioning and child well-being in the context of childhood chronic conditions, researchers have tested family-focused interventions aimed at promoting both child and family well-being through improving the family's condition management capacity. Based on a sample of 70 interventions for families in which there was a child with a chronic physical condition, this analysis examined the nature of family engagement in the interventions. Data were extracted from the intervention reports using a standardized template; conventional content analysis was used to describe family engagement. Interventions varied in focus, structure, and level of family engagement. Investigators most often sought to improve condition control or management, with parent engagement focused on improving capacity to manage the treatment regimen. Few investigators addressed capacity building in the context of family functioning. Recommendations are made for reporting standards for family-focused interventions and for enhancing the family systems grounding of interventions.

Putting Families Into Place: Using Neighborhood-Effects Research and Activity Spaces to Understand Families

PubMed Central

Noah, Aggie J.

2015-01-01

Neighborhood is an important context in which individuals and families are embedded. Yet family studies researchers have been relatively slow to incorporate spatial approaches into family science. Although limited theoretical and methodological attention has been devoted to families in neighborhood-effects research, family scholars can contribute greatly to theories about neighborhood effects, and neighborhood-effects research can help move the field of family studies forward. This article reviews the theories, applications, and limitations of research on neighborhood effects and discusses how family studies can benefit from incorporating a spatial perspective from neighborhood-effects research. I then present an innovative methodology—referred to as activity spaces—emerging in neighborhood-effects research, and I discuss how this approach can be used to better understand the complexity and heterogeneity of families. Last, I highlight ways to incorporate space into family studies by “putting families into place.” PMID:26681979

Spider fauna in Caspian Costal region of Iran.

PubMed

Ghavami, Sahra

2007-03-01

The current study investigated spider fauna of Caspian Costal region of Iran (Guilan, Mazandaran and Golestan provinces) during 2005-2006. Spiders were collected from on the ground and under the stones and grasses by bottle, aspirator, Pitfall trap and pans and from branches, leaves and trunks of different trees and bushes by Steiner and Baggiolini method and insect net. They transferred to the laboratory and classified in 52 species and 51 genera belonged to 20 families. Thirty species, 13 genera and 2 families are reported for the first time from Iran, as follows: Family Agelenidae: Agelena labyrinthica (Clerck, 1757), Cicurina sp., Family Araneidae: Agalenatea redii (Scopoli, 1763), Araniella inconspicua (Simon, 1874), Araniella alpica (C.L. Koch, 1869), Araneus diadematus Clerck, 1757, Cercidia sp., Cyclosa conica (Pallas, 1772), Hypsosinga sanguinea (C.L. Koch,1845), Family Clubionidae: Clubiona neglecta O.P. Camridge, 1862, Family Amaurobiidae, Family Eresidae: Eresus sp., Dresserus sp., Family Gnaphosidae: Aphantaulax sp., Micaria sp., Family Metidae: Zygiella x-notata (Clerck,1757), Family Miturgidae: Cheiracanthium erraticum (Walckenaer, 1802), Cheiracanthium pennyi O.P. Cambridge, 1873, Family Linyphiidae: Microlinyphia sp., Family Lycosidae: Alopecosa pulverulenta (Clerck, 1757), Pardosa amentata (Clerck, 1757), Pardosa agrestis (Westring, 1861), Pardosa monticola (Clerck, 1757), Family Oxyopidae: Oxyopes salticus (Hentx, 1802), Family Philodromidae: Philodromus cespitum (Walckenaer, 1802),Family Pholcidae: Psilochorus simoni (Berland, 1911), Pholcus phalangioides (Fuesslin, 1775), Family Salticidae: Salticus scenicus (Clerck, 1757), Family Tetragnathidae: Tetragnatha montana, Simon, 1874, Tetragnatha javana (Thorell, 1890), Family Theridiidae: Dipoena prona (Menge, 1868), Steatoda albomaculata (Degeer, 1778), Theridion impressum C. L. Koch, Theridion simile C.L. Koch,1836, Family Thomisidae: Misumena vatia (Clerck, 1757), Thanatus formicinus (Clerck, 1757), Thanatus striatus C.L. Koch, 1845, Xysticus cristatus (Clerck, 1757).

Pathways of Risk and Resilience: Impact of a Family Resilience Program on Active-Duty Military Parents.

PubMed

Saltzman, William R; Lester, Patricia; Milburn, Norweeta; Woodward, Kirsten; Stein, Judith

2016-12-01

Over the past decade, studies into the impact of wartime deployment and related adversities on service members and their families have offered empirical support for systemic models of family functioning and a more nuanced understanding of the mechanisms by which stress and trauma reverberate across family and partner relationships. They have also advanced our understanding of the ways in which families may contribute to the resilience of children and parents contending with the stressors of serial deployments and parental physical and psychological injuries. This study is the latest in a series designed to further clarify the systemic functioning of military families and to explicate the role of resilient family processes in reducing symptoms of distress and poor adaptation among family members. Drawing upon the implementation of the Families Overcoming Under Stress (FOCUS) Family Resilience Program at 14 active-duty military installations across the United States, structural equation modeling was conducted with data from 434 marine and navy active-duty families who participated in the FOCUS program. The goal was to better understand the ways in which parental distress reverberates across military family systems and, through longitudinal path analytic modeling, determine the pathways of program impact on parental distress. The findings indicated significant cross-influence of distress between the military and civilian parents within families, families with more distressed military parents were more likely to sustain participation in the program, and reductions in distress among both military and civilian parents were significantly mediated by improvements in resilient family processes. These results are consistent with family systemic and resilient models that support preventive interventions designed to enhance family resilient processes as an important part of comprehensive services for distressed military families. © 2016 Family Process Institute.

Family quality of life of Chinese families of children with intellectual disabilities.

PubMed

Hu, X; Wang, M; Fei, X

2012-01-01

The concepts of quality of life and family quality of life (FQOL) are increasingly being studied in the field of intellectual disabilities (ID) in China as important frameworks for: (1) assessing families' need for supports and services; (2) guiding organisational and service delivery system changes; and (3) evaluating quality family outcomes. The present study focused on exploring the perceptions of Chinese families who have a child with an ID regarding FQOL as well as examining the factor structure of FQOL concept from Chinese families. The Chinese version of the Family Quality of Life Scale was used to survey Chinese families living in the urban and suburban areas of Beijing who have a child with ID. A total of 442 families participated in this study. Confirmatory factor analysis was used to test the factor structure of FQOL. Multivariate analysis was also used to examine group differences among families in terms of family demographic variables. A five-factor structure of the FQOL construct was found in the Chinese sample, suggesting a similar factor structure found from US families in the literature. Different living conditions (e.g. housing and transportation) tended to affect significantly families' satisfaction ratings of their FQOL. It is also found that family income and severity of disability of the child are predictors of families' satisfaction ratings of FQOL. The preliminary findings of this study suggest a cross-cultural factor structure comparability of FQOL between samples in the USA and China. Results call for further examination of the family-centred service and support as a mediator on the interactive relationship between family characteristics, family needs and FQOL outcomes. © 2011 The Authors. Journal of Intellectual Disability Research © 2011 Blackwell Publishing Ltd.

Effectiveness of resource-enhancing family-oriented intervention.

PubMed

Häggman-Laitila, Arja; Tanninen, Hanna-Mari; Pietilä, Anna-Maija

2010-09-01

The purpose of the study was to assess the effectiveness of a resource-enhancing family-oriented intervention. There is very little empirical knowledge of how nurses working in a home context develop relationships with families, what methods they use to enhance families' resources and how such relationships affect the families' health outcomes. The study was designed as a descriptive service evaluation. A total of 129 family members from 30 families with small children participated in the study. Data were collected with family care plans and client reports in 2004-2005. Data were analysed by qualitative content analysis and by descriptive statistical methods. Resource-enhancing discussions were carried out in all family meetings. Other methods were video guidance, creation of a family tree and parents' role map, network collaboration, observation and parent-child group activity. The families needed support mostly in parents' health and well-being, coping with parenthood, upbringing and child care, parents' relationships, social relations and children's health and growth. The families had an average of five support needs at the beginning of the intervention and 1·8 needs at the completion. The families set on average 3·6 and achieved 4·5 goals during the family nursing process. The resource-enhancing family nursing can be used for supporting parenthood, the raising of and caring for the children, strengthening of social support networks, decreasing the need for support from the authorities and enhancing the parents' resources to manage the duties related to their work and studies. The study resulted in empirically based concepts that can be used in the future to construct instruments to evaluate the effectiveness of resource-enhancing family nursing from the perspective of families and family health. The findings add to our professional understanding of resource-enhancing family nursing. © 2010 Blackwell Publishing Ltd.

Family climates: family factors specific to disturbed eating and bulimia nervosa.

PubMed

Laliberté, M; Boland, F J; Leichner, P

1999-09-01

More than a decade of research has characterized the families of individuals with bulimia and bulimia anorexia (Anorexia Nervosa, Binge/Purging Type) as less expressive, less cohesive, and experiencing more conflicts than normal control families. This two-part study investigated variables believed more directly related to disturbed eating and bulimia as contributing to a "family climate for eating disorders." In Study 1. a nonclinical sample of 324 women who had just left home for college and a sample of 121 mothers evaluated their families. Principal-components analyses revealed the same factor structure for both students and mothers, with Family Body Satisfaction, Family Social Appearance Orientation, and Family Achievement Emphasis loading together, representing the hypothesized family climate for eating disorders: the remaining variables loaded with the more traditional family process variables (conflict, cohesion, expressiveness), representing a more general family dysfunction. As predicted, the family climate for eating disorders factor score was a more powerful predictor of disturbed eating. Study 2 extended these findings into a clin ical population, examining whether the family climate for eating disorders variables would distinguish individuals with bulimia from both depressed and healthy controls. Groups of eating-disordered patients (n = 40) and depressed (n = 17) and healthy (n = 27) controls completed family measures. The eating-disordered group scored significantly higher on family climate variables than control groups. Family process variables distinguished clinical groups (depressed and eating disordered) from healthy controls, but not from one another. Controlling for depression removed group differences on family process variables, but family climate variables continued to distinguish the eating-disordered group from both control groups. Indications for further research are discussed.

Family Structure, Family Stability, and Outcomes of Five-Year-Old Children

PubMed Central

Brooks-Gunn, Jeanne; Waldfogel, Jane

2013-01-01

This study exploits data from the Fragile Families and Child Wellbeing Study, a birth cohort study of a diverse sample of children from twenty U.S. cities (N = 3,676), to examine how cognitive, behavioural, and health outcomes of five-year old children differ according to their family structure and family stability. We define three models: one that measures family structure at birth only, a second that measures current family structure at year five conditional on family structure at birth, and a third that measures changes in family structure from birth to age five. We find that while family structure has persistent links to child outcomes, the effects are significantly altered by stability of the family structure over time. These findings remain robust even after addressing selection. PMID:24163735

Family ties: constructing family time in low-income families.

PubMed

Tubbs, Carolyn Y; Roy, Kevin M; Burton, Linda M

2005-03-01

"Family time" is reflected in the process of building and fortifying family relationships. Whereas such time, free of obligatory work, school, and family maintenance activities, is purchased by many families using discretionary income, we explore how low-income mothers make time for and give meaning to focused engagement and relationship development with their children within time constraints idiosyncratic to being poor and relying on welfare. Longitudinal ethnographic data from 61 low-income African American, European American, and Latina American mothers were analyzed to understand how mothers construct family time during daily activities such as talking, play, and meals. We also identify unique cultural factors that shape family time for low-income families, such as changing temporal orientations, centrality of television time, and emotional burdens due to poverty. Implications for family therapy are also discussed.

Treatment Techniques and Outcomes in Multidimensional Family Therapy for Adolescent Behavior Problems

PubMed Central

Hogue, Aaron; Dauber, Sarah; Samuolis, Jessica; Liddle, Howard A.

2010-01-01

The link between treatment techniques and long-term treatment outcome was examined in an empirically supported family-based treatment for adolescent drug abuse. Observational ratings of therapist interventions were used to predict outcomes at 6 and 12 months posttreatment for 63 families receiving multidimensional family therapy. Greater use of in-session family-focused techniques predicted reduction in internalizing symptoms and improvement in family cohesion. Greater use of family-focused techniques also predicted reduced externalizing symptoms and family conflict, but only when adolescent focus was also high. In addition, greater use of adolescent-focused techniques predicted improvement in family cohesion and family conflict. Results suggest that both individual and multiperson interventions can exert an influential role in family-based therapy for clinically referred adolescents. PMID:17176187

The Family in Us: Family History, Family Identity and Self-Reproductive Adaptive Behavior.

PubMed

Ferring, Dieter

2017-06-01

This contribution is an essay about the notion of family identity reflecting shared significant experiences within a family system originating a set of signs used in social communication within and between families. Significant experiences are considered as experiences of events that have an immediate impact on the adaptation of the family in a given socio-ecological and cultural context at a given historical time. It is assumed that family history is stored in a shared "family memory" holding both implicit and explicit knowledge and exerting an influence on the behavior of each family member. This is described as transgenerational family memory being constituted of a system of meaningful signs. The crucial dimension underlying the logic of this essay are the ideas of adaptation as well as self-reproduction of systems.

Is work–family balance more than conflict and enrichment?

PubMed Central

Carlson, Dawn S.; Grzywacz, Joseph G.; Zivnuska, Suzanne

2009-01-01

This study deepens our theoretical and practical understanding of work–family balance, defined as the ‘accomplishment of role-related expectations that are negotiated and shared between an individual and his/her role-related partners in the work and family domains’ (Grzywacz & Carlson, 2007: 458). We develop a new measure of work–family balance and establish discriminant validity between it, work–family conflict, and work–family enrichment. Further, we examine the relationship of work–family balance with six key work and family outcomes. Results suggest that balance explains variance beyond that explained by traditional measures of conflict and enrichment for five of six outcomes tested: job satisfaction, organizational commitment, family satisfaction, family performance, and family functioning. We conclude with a discussion of the applications of our work. PMID:20148121

Family environment patterns in families with bipolar children.

PubMed

Belardinelli, Cecilia; Hatch, John P; Olvera, Rene L; Fonseca, Manoela; Caetano, Sheila C; Nicoletti, Mark; Pliszka, Steven; Soares, Jair C

2008-04-01

We studied the characteristics of family functioning in bipolar children and healthy comparison children. We hypothesized that the family environment of bipolar children would show greater levels of dysfunction as measured by the Family Environment Scale (FES). We compared the family functioning of 36 families that included a child with DSM-IV bipolar disorder versus 29 comparison families that included only healthy children. All subjects and their parents were assessed with the K-SADS-PL interview. The parents completed the FES to assess their current family functioning. Multivariate analysis of variance was used to compare the family environment of families with and without offspring with bipolar disorder. Parents of bipolar children reported lower levels of family cohesion (p<0.001), expressiveness (p=0.005), active-recreational orientation (p<0.001), intellectual-cultural orientation (p=0.04) and higher levels of conflict (p<0.001) compared to parents with no bipolar children. Secondary analyses within the bipolar group revealed lower levels of organization (p=0.031) and cohesion (p=0.014) in families where a parent had a history of mood disorders compared to families where parents had no history of mood disorders. Length of illness in the affected child was inversely associated with family cohesion (r=-0.47, p=0.004). Due to the case-control design of the study, we cannot comment on the development of these family problems or attribute their cause specifically to child bipolar disorder. Families with bipolar children show dysfunctional patterns related to interpersonal interactions and personal growth. A distressed family environment should be addressed when treating children with bipolar disorder.

Family Partner Intervention Influences Self-Care Confidence and Treatment Self-Regulation in Patients with Heart Failure

PubMed Central

Stamp, Kelly D.; Dunbar, Sandra B.; Clark, Patricia C.; Reilly, Carolyn M.; Gary, Rebecca A.; Higgins, Melinda; Ryan, Richard M

2015-01-01

Background Heart failure self-care requires confidence in one’s ability and motivation to perform a recommended behavior. Most self-care occurs within a family context, yet little is known about the influence of family on heart failure self-care or motivating factors. Aims To examine the association of family functioning and the self-care antecedents of confidence and motivation among heart failure participants and determine if a family partnership intervention would promote higher levels of perceived confidence and treatment self-regulation (motivation) at four and eight months compared to patient-family education or usual care groups. Methods Heart failure patients (N = 117) and a family member were randomized to a family partnership intervention, patient-family education or usual care groups. Measures of patient’s perceived family functioning, confidence, motivation for medications and following a low-sodium diet were analyzed. Data were collected at baseline, four and eight months. Results Family functioning was related to self-care confidence for diet (p=.02) and autonomous motivation for adhering to their medications (p=.05 and diet p=0.2). The family partnership intervention group significantly improved confidence (p=.05) and motivation (medications (p=.004; diet p=.012) at four months whereas patient-family education group and usual care did not change. Conclusion Perceived confidence and motivation for self-care was enhanced by family partnership intervention, regardless of family functioning. Poor family functioning at baseline contributed to lower confidence. Family functioning should be assessed to guide tailored family-patient interventions for better outcomes. PMID:25673525

Free-choice family learning experiences at informal astronomy observing events

NASA Astrophysics Data System (ADS)

Wenger, Matthew C.

This qualitative study is an exploratory look at family experiences at night time telescope observing events, often called star parties. Four families participated in this study which looked at their expectations, experiences and agendas as well as the roles that identity and family culture played in the negotiation of meaning. Two families who had prior experience with attending star parties were recruited ahead of time and two other families who were first time visitors were recruited on-site at the observing event. Data were collected at two star parties. At each event, one experienced family was paired with an on-site family for the purposes of facilitating conversations about expectations and prior experiences. The results of this study showed that learning is constantly occurring among families, and that star parties and family culture were mediational means for making meaning. Expectations and agendas were found to affect the families' star party experiences and differences were observed between the expectations and experiences of families based on their prior experiences with star parties. These data also showed that family members are actively negotiating their individual and family identities. These families use their cultural history together to make sense of their star party experiences; however, the meaning that families were negotiating was often focused more on developing family and individual identity rather than science content. The families in this study used the star party context as a way to connect with each other, to make sense of their prior experiences, and as raw material for making sense of future experiences.

The Dyadic Effects of Family Cohesion and Communication on Health-Related Quality of Life: The Moderating Role of Sex.

PubMed

Lim, Jung-Won; Shon, En-Jung

Spouses' ability to care for survivors can be particularly challenging because patients and spouses are interdependent and mutually influence one another. Family functioning such as family cohesion and communication may play a primary role in improving the health-related quality of life (HRQOL) of couples, given that cancer can influence family dynamics. The aims of this study were to investigate the mediating effect of family communication on the relationship between family cohesion and HRQOL and examine the moderating effect of sex on this relationship among cancer survivor-spouse dyads. A total of 91 cancer survivors with a diagnosis of breast, colorectal, or prostate cancer and their spouses were recruited from the University Hospital Registry in Cleveland, Ohio. The dyadic data were analyzed using structural equation modeling with the actor-partner interdependence mediation model. Findings demonstrated that the spouses' own perceived family communication mediated the associations between their own family cohesion and physical HRQOL and between the survivors' family cohesion and physical HRQOL. The spouse actor effects between family communication and HRQOL significantly differed by sex. Enhancing family cohesion and communication within the family can improve the spouses' HRQOL. Findings regarding sex differences serve as a rationale for gender-based approaches to improving HRQOL in survivorship care in the family context. Couple- and/or family-based interventions should be designed to enhance family cohesion and improve family communication skills for effective adjustments within couples and families. Supportive care within the family context can be promoted to address the diverse challenges of survivorship care.

Asteroid Family Associations of Active Asteroids

NASA Astrophysics Data System (ADS)

Hsieh, Henry H.; Novaković, Bojan; Kim, Yoonyoung; Brasser, Ramon

2018-02-01

We report on the results of a systematic search for associated asteroid families for all active asteroids known to date. We find that 10 out of 12 main-belt comets (MBCs) and five out of seven disrupted asteroids are linked with known or candidate families, rates that have ∼0.1% and ∼6% probabilities, respectively, of occurring by chance, given the overall family association rate of 37% for asteroids in the main asteroid belt. We find previously unidentified family associations between 238P/Read and the candidate Gorchakov family, 311P/PANSTARRS and the candidate Behrens family, 324P/La Sagra and the Alauda family, 354P/LINEAR and the Baptistina family, P/2013 R3-B (Catalina-PANSTARRS) and the Mandragora family, P/2015 X6 (PANSTARRS) and the Aeolia family, P/2016 G1 (PANSTARRS) and the Adeona family, and P/2016 J1-A/B (PANSTARRS) and the Theobalda family. All MBCs with family associations belong to families that contain asteroids with primitive taxonomic classifications and low average reported albedos (\\overline{{p}V}≲ 0.10), while disrupted asteroids with family associations belong to families that contain asteroids that span wider ranges of taxonomic types and average reported albedos (0.06< \\overline{{p}V}< 0.25). These findings are consistent with MBC activity being closely correlated to composition (i.e., whether an object is likely to contain ice), while disrupted asteroid activity is not as sensitive to composition. Given our results, we describe a sequence of processes by which the formation of young asteroid families could lead to the production of present-day MBCs.

[Experiences of the family living with severe mental illness: a qualitative study in Navarre].

PubMed

Acero González, A R; Cano-Prous, A; Canga, A

2016-01-01

It is estimated that 1% of the general population suffers from severe mental illness (SMI). In most cases, families are the ones providing support and direct care to the ill relative, which in turn results in the family being the unit that lives with the mental illness. In Spain, two key aspects have been barely explored: the relationship between the family and the mental health system; and the knowledge of families and the possible transfer of such knowledge to other families. The aim of this paper is to contribute to exploring these two aspects. A qualitative study with a narrative approach was implemented in the Foral Community of Navarre (Spain). The study consisted of in-depth interviews with families living with SMI. Two interviews were conducted with each family (which included the individual diagnosed with a mental illness). A multimodal analysis (structural, thematic and dialogical) was conduc-ted with each family. Comparative analyses between families were also performed. A total of 6 families were interviewed with a total of 18 participants. Findings were grouped around two central catego-ries: requirements of families and family to family. The first category includes improving relationships with mental health provi-ders, medications, psychosocial rehabilitation centers and supporting families. The second category includes recommendations from the perspective of the relative with a SMI and those without it. Families would like to receive a higher degree of support from mental-health providers. At the same time, families should be considered as important sources of knowledge and support for the treatment of other families living with SMI.

An Integrated Framework for Effective and Efficient Communication with Families in the Adult Intensive Care Unit.

PubMed

Seaman, Jennifer B; Arnold, Robert M; Scheunemann, Leslie P; White, Douglas B

2017-06-01

The increased focus on patient and family-centered care in adult intensive care units (ICUs) has generated multiple platforms for clinician-family communication beyond traditional interdisciplinary family meetings (family meetings)-including family-centered rounds, bedside or telephone updates, and electronic family portals. Some clinicians and administrators are now using these platforms instead of conducting family meetings. For example, some institutions are moving toward using family-centered rounds as the main platform for clinician-family communication, and some physicians rely on brief daily updates to the family at the bedside or by phone, in lieu of family meetings. We argue that although each of these platforms is useful in some circumstances, there remains an important role for family meetings. We outline five goals of clinician-family communication-establishing trust, providing emotional support, conveying clinical information, understanding the patient as a person, and facilitating careful decision making-and we examine the extent to which various communication platforms are likely to achieve the goals. We argue that because no single platform can achieve all communication goals, an integrated strategy is needed. We present a model that integrates multiple communication platforms to effectively and efficiently support families across the arc of an ICU stay. Our framework employs bedside/telephone conversations and family-centered rounds throughout the admission to address high informational needs, along with well-timed family meetings that attend to families' emotions as well as patients' values and goals. This flexible model uses various communication platforms to achieve consistent, efficient communication throughout the ICU stay.

Exploring Multilevel Factors for Family Engagement in Home Visiting Across Two National Models.

PubMed

Latimore, Amanda D; Burrell, Lori; Crowne, Sarah; Ojo, Kristen; Cluxton-Keller, Fallon; Gustin, Sunday; Kruse, Lakota; Hellman, Daniela; Scott, Lenore; Riordan, Annette; Duggan, Anne

2017-07-01

The associations of family, home visitor and site characteristics with family engagement within the first 6 months were examined. The variation in family engagement was also explored. Home visiting program participants were drawn from 21 Healthy Families America sites (1707 families) and 9 Nurse-Family Partnership sites (650 families) in New Jersey. Three-level nested generalized linear mixed models assessed the associations of family, home visitor and site characteristics with family receipt of a high dose of services in the first 6 months of enrollment. A family was considered to have received a high dose of service in the first 6 months of enrollment if they were active at 6 months and had received at least 50% of their expected visits in the first 6 months. In general, both home visiting programs engaged, at a relatively high level (Healthy Families America (HFA) 59%, Nurse-Family Partnership (NFP) 64%), with families demonstrating high-risk characteristics such as lower maternal education, maternal smoking, and maternal mental health need. Home visitor characteristics explained more of the variation (87%) in the receipt of services for HFA, while family characteristics explained more of the variation (75%) in the receipt of services for NFP. At the family level, NFP may improve the consistency with which they engage families by increasing retention efforts among mothers with lower education and smoking mothers. HFA sites seeking to improve engagement consistency should consider increasing the flexible in home visitor job responsibilities and examining the current expected-visit policies followed by home visitors on difficult-to-engage families.

Impact of Family History Assessment on Communication with Family Members and Health Care Providers: A report from the Family Healthware™ Impact Trial (FHITr)

PubMed Central

Wang, Catharine; Sen, Ananda; Plegue, Melissa; Ruffin, Mack T.; O'Neill, Suzanne M.; Rubinstein, Wendy S.; Acheson, Louise S.

2015-01-01

Objective This study examines the impact of Family Healthware™ on communication behaviors; specifically, communication with family members and health care providers about family health history. Methods A total of 3786 participants were enrolled in the Family Healthware™ Impact Trial (FHITr) in the United States from 2005-7. The trial employed a two-arm cluster-randomized design, with primary care practices serving as the unit of randomization. Using generalized estimating equations (GEE), analyses focused on communication behaviors at 6 month follow-up, adjusting for age, site and practice clustering. Results A significant interaction was observed between study arm and baseline communication status for the family communication outcomes (ps<.01), indicating that intervention had effects of different magnitude between those already communicating at baseline and those who were not. Among participants who were not communicating at baseline, intervention participants had higher odds of communicating with family members about family history risk (OR=1.24, p=0.042) and actively collecting family history information at follow-up (OR=2.67, p=0.026). Family Healthware™ did not have a significant effect on family communication among those already communicating at baseline, or on provider communication, regardless of baseline communication status. Greater communication was observed among those at increased familial risk for a greater number of diseases. Conclusion Family Healthware™ prompted more communication about family history with family members, among those who were not previously communicating. Efforts are needed to identify approaches to encourage greater sharing of family history information, particularly with health care providers. PMID:25901453

Impact of family history assessment on communication with family members and health care providers: A report from the Family Healthware™ Impact Trial (FHITr).

PubMed

Wang, Catharine; Sen, Ananda; Plegue, Melissa; Ruffin, Mack T; O'Neill, Suzanne M; Rubinstein, Wendy S; Acheson, Louise S

2015-08-01

This study examines the impact of Family Healthware™ on communication behaviors; specifically, communication with family members and health care providers about family health history. A total of 3786 participants were enrolled in the Family Healthware™ Impact Trial (FHITr) in the United States from 2005-7. The trial employed a two-arm cluster-randomized design, with primary care practices serving as the unit of randomization. Using generalized estimating equations (GEE), analyses focused on communication behaviors at 6month follow-up, adjusting for age, site and practice clustering. A significant interaction was observed between study arm and baseline communication status for the family communication outcomes (p's<.01), indicating that intervention had effects of different magnitude between those already communicating at baseline and those who were not. Among participants who were not communicating at baseline, intervention participants had higher odds of communicating with family members about family history risk (OR=1.24, p=0.042) and actively collecting family history information at follow-up (OR=2.67, p=0.026). Family Healthware™ did not have a significant effect on family communication among those already communicating at baseline, or on provider communication, regardless of baseline communication status. Greater communication was observed among those at increased familial risk for a greater number of diseases. Family Healthware™ prompted more communication about family history with family members, among those who were not previously communicating. Efforts are needed to identify approaches to encourage greater sharing of family history information, particularly with health care providers. Copyright © 2015 Elsevier Inc. All rights reserved.

20 CFR 229.49 - Adjustment of benefits under family maximum for change in family group.

Code of Federal Regulations, 2010 CFR

2010-04-01

... for change in family group. 229.49 Section 229.49 Employees' Benefits RAILROAD RETIREMENT BOARD... Overall Minimum Rate § 229.49 Adjustment of benefits under family maximum for change in family group. (a) Increase in family group. If an overall minimum rate is adjusted for the family maximum and an additional...

Single-Parent Families. Sage Sourcebooks for the Human Services Series, Volume 24.

ERIC Educational Resources Information Center

Kissman, Kris; Allen, Jo Ann

More than one fourth of all families today are one-parent families, and almost 90 percent of those families are headed by women. This book focuses on assessment and intervention with one-parent families, particularly mother-headed families, based on gender-sensitive principles combined with other family-centered strategies to help accentuate the…

24 CFR 5.518 - Types of preservation assistance available to mixed families and other families.

Code of Federal Regulations, 2011 CFR

2011-04-01

... available to mixed families and other families. 5.518 Section 5.518 Housing and Urban Development Office of... Restrictions on Assistance to Noncitizens § 5.518 Types of preservation assistance available to mixed families and other families. (a) Continued assistance—(1) General. A mixed family may receive continued housing...

24 CFR 5.518 - Types of preservation assistance available to mixed families and other families.

Code of Federal Regulations, 2013 CFR

2013-04-01

... available to mixed families and other families. 5.518 Section 5.518 Housing and Urban Development Office of... Restrictions on Assistance to Noncitizens § 5.518 Types of preservation assistance available to mixed families and other families. (a) Continued assistance—(1) General. A mixed family may receive continued housing...

24 CFR 5.518 - Types of preservation assistance available to mixed families and other families.

Code of Federal Regulations, 2012 CFR

2012-04-01

... available to mixed families and other families. 5.518 Section 5.518 Housing and Urban Development Office of... Restrictions on Assistance to Noncitizens § 5.518 Types of preservation assistance available to mixed families and other families. (a) Continued assistance—(1) General. A mixed family may receive continued housing...

24 CFR 5.518 - Types of preservation assistance available to mixed families and other families.

Code of Federal Regulations, 2014 CFR

2014-04-01

... available to mixed families and other families. 5.518 Section 5.518 Housing and Urban Development Office of... Restrictions on Assistance to Noncitizens § 5.518 Types of preservation assistance available to mixed families and other families. (a) Continued assistance—(1) General. A mixed family may receive continued housing...

Conflict between Work and Family among New Zealand Teachers with Dependent Children

ERIC Educational Resources Information Center

Palmer, Melanie; Rose, Dennis; Sanders, Matthew; Randle, Fiona

2012-01-01

Changes in family and employment patterns have lead to an increasing need for families to balance work and family roles. Little research has examined work and family conflict among teachers. In the present study, 69 New Zealand teachers completed a survey examining occupational-related demands, family-related demands, work and family conflict, and…

Australian Family Research Conference Proceedings (Canberra, Australia, November 23-25, 1983). Volume VI: Family Life.

ERIC Educational Resources Information Center

Institute of Family Studies, Melbourne (Australia).

Family life is the focus of this sixth volume in a series containing the proceedings of the 1983 Australian Family Research Conference. The papers are organized under two major sections: Children and Families and Family Environments. Papers and authors included are: "Family Conflict and Child Competence" (Gay Ochiltree and Paul Amato),…

The Influence of Family Climate and Family Process on Child Development.

ERIC Educational Resources Information Center

Bell, Linda G.; Bell, David C.

This study investigates the relationship between the degree of individuation in families and the personality development of adolescent family members. A subsample of 30 white, middle-class families were chosen for analysis from a larger sample of 99 families. Fifteen families from the subsample had adolescent girls who scored high, and fifteen had…

From Family Deficit to Family Strength: Viewing Families' Contributions to Children's Learning from a Family Resilience Perspective

ERIC Educational Resources Information Center

Amatea, Ellen S.; Smith-Adcock, Sondra; Villares, Elizabeth

2006-01-01

This article presents an overview of a research-informed family resilience framework, developed as a conceptual map to guide school counselors' preventive and interventive efforts with students and their families. Key processes that characterize children's and families' resilience are outlined along with recommendations for how school counselors…

Stressors and Enhancers in the Marital/Family Life of Family Professionals and Their Spouses.

ERIC Educational Resources Information Center

Duncan, Stephen F.; Goddard, H. Wallace

1993-01-01

Assessed how work as family professional is uniquely enhancing and stressful and whether enhancers and stressors are correlated with marital and family quality. Findings from 59 family professionals and their spouses strengthen idea that there are marital and family life enhancers and stressors uniquely associated with work as family professional.…

Family Support Builds Stronger Families: The Roots of Family-Supportive Child Care

ERIC Educational Resources Information Center

Seiderman, Ethel

2009-01-01

Parent Services Project (PSP) is one model of family support that emerged from the heightened awareness of families' needs. Founded in 1980 to integrate family support into four San Francisco Bay Area early childhood programs, PSP since has spread to more than 800 organizations serving 30,000 families in Alaska, California, Delaware, Florida,…

[The total-quality-management-analysis of the continuation and discontinuation of alcohol family treatment: a grassroots approach].

PubMed

Nishikawa, K; Tatsuki, S

2001-06-01

A family support/treatment program was provided to thirty-three cases where a drinking family member (identified patient) had shown alcohol related problems but not yet admitted the problem. After a period of between thirteen and twenty-one months of family treatment, fourteen (42.4%) identified patients started their own treatment. The only statistically significant factor that was related to the patients' treatment program participation was the continuation of family members' involvement in a family treatment program. Among the thirty-three cases, a little less than one half (48.5%) continued the family program. In order to increase the patients' participation, it is crucial to encourage family members to continue their family support/treatment program. In order to identify factors that contribute treatment continuation as well as dropouts, workshops were held with those who dropped out and those who continued the family treatment program. The Total-Quality-Management (TQM) affinity and arrow diagram techniques were employed to classify the participants' statements and to find cause-effect relationships among the identified factors, respectively. Five family treatment discontinuation factors were identified: 1) a lack of information about family support program, 2) resistance against a "family change" orientation in family treatment program, 3) family member burnout, 4) a misfit between family needs for immediate problem solutions and what family program offers, and 5) a temporal improvement of patients' drinking problems. While widely varied factors were found to contribute discontinuation, only a very few factors were identified to facilitate the treatment continuation. It was concluded that treatment discontinuation, rather than continuation, was the norm among the families of problem drinkers. Based on the above findings, three kaizen plans were proposed. First, in order to make sure that family members obtain necessary information about the family support/treatment program, a pamphlet would be created and handed out to those who come to family treatment. Second, family support efforts would be emphasized more. Treatment staff is expected to become more cautious with regard to the family behavior change facilitation, especially at the early stage. Third, treatment staff is expected to become more aggressive about contacting family group members when they do not show up to a meeting.

[Family dynamics and chronic illness: children with diabetes in the context of their families].

PubMed

Wirlach-Bartosik, S; Schubert, M T; Freilinger, M; Schober, E

2005-01-01

The present study is based on the assumption of an interaction between family functioning and chronic illness. Using a systemic approach, the intra-familial situation of families with a diabetes-affected child is examined. 44 families were evaluated using a family diagnostic instrument ("Familienbögen") and compared with 31 control families with a healthy child. Furthermore, the study looked at the influence of the level of family functioning on glycemic control, as measured by HbA1c values, and vice versa. Families with a child affected by diabetes showed significantly more dysfunctional domains and higher discrepancies of the ratings in the family diagnostic instrument (p < 0.05). Unexpectedly, no significant interaction between family functioning and glycemic control was found. Poor glycemic control therefore did not have any negative effects on the family dynamics, in fact, the opposite was often the case. Also, the relationship between siblings was judged more positively when one of the siblings was chronically ill (p < 0.05). The results show that despite the fact that diabetes in children may lead to an increase in impairment of intra-familial dynamics, it may, at the same time, offer opportunities for an improvement of family relationships. However, if physiological parameters deteriorate in the child (poor glycemic control), family problems seem to become less important. Success in the treatment of diabetes patients should therefore not only be measured by the quality of glycemic control, but also by considering psychological factors and aspects of family dynamics.

'You put it all together' - families' evaluation of participating in Family Health Conversations.

PubMed

Benzein, Eva; Olin, Cecilia; Persson, Carina

2015-03-01

To evaluate the Family Health Conversations from the perspective of families living with chronic illness. This study has a descriptive qualitative design using semi-structured evaluative family interviews and conventional content analysis. The study was approved by a Regional Ethical Review Board. Family Health Conversations were used as an intervention with 14 families living with chronic illness. The outcome measures consisted of evaluative family interviews. Families' experiences of the conversations embraced their structure and the interactions with the conversation leaders. All families were satisfied with the conversations, pointing to the importance of having them early in the illness process. The opportunity to talk with someone outside the family was strongly emphasised as promoting well-being. The experienced significance of the conversations was captured in four categories: creating a whole picture, that is, being given the opportunity to listen to other family members' experiences and fill in potential memory gaps; making the situation manageable, that is, receiving support from other participants in order to handle problems and gain control; facilitating healing, that is, being able to tell their story about what had previously been 'the unspeakable'; and strengthened family cohesion, that is, increased understanding for each other's experiences, thus bringing family members closer together. Most families were partners, which could possibly limit transferability of the findings to families constituted by couples. Family Health Conversations should be offered as a part of standard care shortly after diagnosis and at various transitions in life. © 2014 Nordic College of Caring Science.

Family diabetes matters: a view from the other side.

PubMed

Samuel-Hodge, Carmen D; Cene, Crystal W; Corsino, Leonor; Thomas, Chelsea; Svetkey, Laura P

2013-03-01

Typically, chronic disease self-management happens in a family context, and for African American adults living with diabetes, family seems to matter in self-management processes. Many qualitative studies describe family diabetes interactions from the perspective of adults living with diabetes, but we have not heard from family members. To explore patient and family perspectives on family interactions around diabetes. Qualitative study using focus group methodology. PARTICIPANTS & APPROACH: We conducted eight audiotaped focus groups among African Americans (four with patients with diabetes and four with family members not diagnosed with diabetes), with a focus on topics of family communication, conflict, and support. The digital files were transcribed verbatim, coded, and analyzed using qualitative data analysis software. Directed content analysis and grounded theory approaches guided the interpretation of code summaries. Focus groups included 67 participants (81 % female, mean age 64 years). Family members primarily included spouses, siblings, and adult children/grandchildren. For patients with diabetes, central issues included shifting family roles to accommodate diabetes and conflicts stemming from family advice-giving. Family members described discomfort with the perceived need to police or "stand over" the diabetic family member, not wanting to "throw diabetes in their [relative's] face," perceiving their communications as unhelpful, and confusion about their role in diabetes care. These concepts generated an emergent theme of "family diabetes silence." Diabetes silence, role adjustments, and conflict appear to be important aspects to address in family-centered diabetes self-management interventions. Contextual data gathered through formative research can inform such family-centered intervention development.

Information and professional support: key factors in the provision of family-centred early childhood intervention services.

PubMed

Fordham, L; Gibson, F; Bowes, J

2012-09-01

Much has been written on the principles of family-centred practice and on the service delivery methods and skills required of its practitioners. Far less has been written from the perspective of families whose children have a disability. The aims of this study were twofold: firstly to understand families' experiences of family-centred early childhood intervention services and secondly to explore other factors that might impact on these experiences. One hundred and thirty families attending two established early childhood intervention services in New South Wales, Australia completed a survey incorporating the Measure of Processes of Care-56, the Family Empowerment Scale, the Family Support Scale and the Parenting Daily Hassles Scale. Consistent with previous research using the Measure of Processes of Care-56, 'respectful and supportive care' was the domain of care families rated to occur most and 'provision of general information' was the domain they rated to occur least. Significant positive relationships existed between families' ratings of family-centred care and feelings of empowerment. Being provided with general information was strongly correlated with family empowerment. Families' social support networks played an important role but support from professionals was most strongly correlated with families' experiences of family-centred care. Finally, families whose children's early intervention services were co-ordinated by a professional experienced significantly better care. The provision of general information and professional support are key components of family-centred early childhood intervention services. © 2011 Blackwell Publishing Ltd.

Family ecology of young children with cerebral palsy.

PubMed

LaForme Fiss, A; Chiarello, L A; Bartlett, D; Palisano, R J; Jeffries, L; Almasri, N; Chang, H-J

2014-07-01

Family ecology in early childhood may influence children's activity and participation in daily life. The aim of this study was to describe family functioning, family expectations of their children, family support to their children, and supports for families of young children with cerebral palsy (CP) based on children's gross motor function level. Participants were 398 children with CP (mean age = 44.9 months) and their parents residing in the USA and Canada. Parents completed four measures of family ecology, the Family Environment Scale (FES), Family Expectations of Child (FEC), Family Support to Child (FSC) and Family Support Scale (FSS). The median scores on the FES indicated average to high family functioning and the median score on the FSS indicated that families had helpful family supports. On average, parents reported high expectations of their children on the FEC and strong support to their children on the FSC. On the FES, higher levels of achievement orientation were reported by parents of children in Gross Motor Function Classification System (GMFCS) level II than parents of children in level I, and higher levels of control were reported by parents of children in level I than parents of children in level IV. On the FEC, parents of children with limited gross motor function (level V) reported lower expectations than parents of children at all other levels. Family ecology, including family strengths, expectations, interests, supports and resources, should be discussed when providing interventions and supports for young children with CP and their families. © 2013 John Wiley & Sons Ltd.

A qualitative exploration of oncology nurses' family assessment practices in Denmark and Australia.

PubMed

Coyne, Elisabeth; Dieperink, Karin B

2017-02-01

The nurses' ability to provide supportive care to the patient and the family is influenced by their family assessment skills, which provide them with understanding of the family needs and strengths. When a patient is diagnosed with cancer, it is the family who provides the long-term support for the patient, and nurses need to understand the family needs in order to provide holistic care. The objective of the present study is to understand the factors that influence nurses' family assessment practices in adult oncology setting in Denmark and Australia. An interpretive qualitative study was conducted guided by the family systems theory. Focus groups were completed with 62 nurses working in adult oncology areas in Denmark and Australia. A thematic analysis and a computer-generated concept mapping were completed to identify themes within the data. Overall, the nurses valued family as part of the patient care and worked to understand the family concerns. However, the family assessment process was unstructured and did not enable holistic family support. Nurses from both countries discussed that experience and ability to engage with the family influenced the nurse's role in family assessment. This study identified that nurses value family as part of patient care, however struggle to assess and support families during oncology care. There is a need for a structured assessment approach and education on family assessment, which could be used across the two countries and possibly internationally.

Latino values in the context of palliative care: illustrative cases from the Family Focused Grief Therapy trial.

PubMed

Del Gaudio, F; Hichenberg, S; Eisenberg, M; Kerr, E; Zaider, T I; Kissane, D W

2013-05-01

Clinicians meet a variety of ethnicities among patients and families in hospice programs. This article focuses on Latino families. Within a controlled trial of family therapy in the context of palliative care, 17 families identified as Hispanic. Five were examined qualitatively herein. A synopsis of each family's narrative is presented here. Patterns of strong family loyalty (Familismo), the gender roles of Machismo and Marianismo, the importance of family tradition, expectations about caregiving, and the place of faith and religion emerged as prominent and able potentially to impact on the therapy. Family therapists need to be thoughtful about cultural issues as they strive to support families.

Predictors of family strength: the integrated spiritual-religious/resilient perspective for understanding the healthy/strong family.

PubMed

Ghaffari, Majid; Fatehizade, Maryam; Ahmadi, Ahmad; Ghasemi, Vahid; Baghban, Iran

2013-01-01

The present study aimed to investigate the effects of spiritual well-being and family protective factors on the family strength in a propositional structural model. The research population consisted of all the married people of the Isfahan, Iran, in 2012 with preschool-aged children and in the first decade of marriage with at least eight grades of educational level. Three hundred and ninety five voluntary and unpaid participants were selected randomly through multi-stage sampling from seven regions of the city. The instruments used were the Spiritual Well-being Scale, Inventory of Family Protective Factors, and Family Strength Scale. Descriptive statistics and a structural equation modeling analytic approach were used. The analytic model predicted 82% of the variance of the family strength. The total effect of the spiritual well-being on the family strength was higher compared to the family protective factors. Furthermore, spiritual well-being predicted 43% of the distribution of the family protective factors and had indirect effect on the family strength through the family protective factors (p < 0.001). The results of this study confirmed the interrelationships among spiritual well-being and family protective factors, and their simultaneous effects on family strength. Family counselors may employ an integrated spiritual-religious/resilient perspective to inform their strength-based work with individuals and their families. None.

Implementation of a Nurse-Led Family Meeting in a Neuroscience Intensive Care Unit.

PubMed

Wu, Huixin; Ren, Dianxu; Zinsmeister, Glenn R; Zewe, Gretchen E; Tuite, Patricia K

2016-01-01

The aims of this study were to develop, implement, and evaluate the impact of early intensive care unit (ICU) nurse-led family meetings on nurse-family communication, family decision making, and satisfaction of family members. Intensive care unit nurses are in an ideal position to meet family needs, and family members may cope better with the crisis of an ICU admission if consistent honest information is provided by nurses; however, there are no early ICU family meetings led by bedside nurses. This quality improvement project was implemented in a 10-bed neuroscience ICU over a 3-month period. A convenience sample of 23 nurses participated in the project. Following development of a communication protocol to facilitate nurse-led meetings, the nurses received education and then implemented the protocol. Thirty-one family members participated in the project. Family members were surveyed before and after the meetings. Mean meeting time was 26 (SD, 14) minutes. Following implementation of the meetings, findings demonstrated that families felt that communication improved (P = .02 and P = .008), they had appropriate information for decision making allowing them to feel in control (P = .002), and there was an increase in family satisfaction (P = .001). Early ICU nurse-led family meetings were feasible, improved communication between ICU nurses and family members, facilitated decision making in ICU families, and increased satisfaction of family members.

Psychological health of military children: longitudinal evaluation of a family-centered prevention program to enhance family resilience.

PubMed

Lester, Patricia; Stein, Judith A; Saltzman, William; Woodward, Kirsten; MacDermid, Shelley W; Milburn, Norweeta; Mogil, Catherine; Beardslee, William

2013-08-01

Family-centered preventive interventions have been proposed as relevant to mitigating psychological health risk and promoting resilience in military families facing wartime deployment and reintegration. This study evaluates the impact of a family-centered prevention program, Families OverComing Under Stress Family Resilience Training (FOCUS), on the psychological adjustment of military children. Two primary goals include (1) understanding the relationships of distress among family members using a longitudinal path model to assess relations at the child and family level and (2) determining pathways of program impact on child adjustment. Multilevel data analysis using structural equation modeling was conducted with deidentified service delivery data from 280 families (505 children aged 3-17) in two follow-up assessments. Standardized measures included service member and civilian parental distress (Brief Symptom Inventory, PTSD Checklist-Military), child adjustment (Strengths and Difficulties Questionnaire), and family functioning (McMaster Family Assessment Device). Distress was significantly related among the service member parent, civilian parent, and children. FOCUS improved family functioning, which in turn significantly reduced child distress at follow-up. Salient components of improved family functioning in reducing child distress mirrored resilience processes targeted by FOCUS. These findings underscore the public health potential of family-centered prevention for military families and suggest areas for future research. Reprint & Copyright © 2013 Association of Military Surgeons of the U.S.

Mental Health and Family Relations: Correlated Reports from People Who Inject Drugs and their Family Members in Vietnam

PubMed Central

Li, Li; Tuan, Nguyen Anh; Liang, Li-Jung; Lin, Chunqing; Farmer, Shu C.; Flore, Martin

2013-01-01

Background This article explores the association of people who inject drugs and their family members in terms of mental health and family relations. The objective was to understand the family context and its impact on people who inject drugs in a family-oriented culture in Vietnam. Methods Cross-sectional assessment data were gathered from 83 people who inject drugs and 83 of their family members recruited from four communes in Phú Thọ province, Vietnam. Depressive symptoms and family relations were measured for both people who inject drugs and family members. Internalized shame and drug-using behavior were reported by people who inject drugs, and caregiver burden was reported by family members. Results We found that higher level of drug using behavior of people who inject drugs was significantly associated with higher depressive symptoms and lower family relations reported by themselves as well as their family members. Family relations reported by people who inject drugs and their family members were positively correlated. Conclusion The findings highlight the need for interventions that address psychological distress and the related challenges faced by family members of people who inject drugs. The article has policy implication which concludes with an argument for developing strategies that enhance the role of families in supporting behavioral change of people who inject drugs. PMID:23910167

Mental health and family relations among people who inject drugs and their family members in Vietnam.

PubMed

Li, Li; Tuan, Nguyen Anh; Liang, Li-Jung; Lin, Chunqing; Farmer, Shu C; Flore, Martin

2013-11-01

This article explores the association of people who inject drugs and their family members in terms of mental health and family relations. The objective was to understand the family context and its impact on people who inject drugs in a family-oriented culture in Vietnam. Cross-sectional assessment data were gathered from 83 people who inject drugs and 83 of their family members recruited from four communes in Phú Thọ province, Vietnam. Depressive symptoms and family relations were measured for both people who inject drugs and family members. Internalized shame and drug-using behavior were reported by people who inject drugs, and caregiver burden was reported by family members. We found that higher level of drug using behavior of people who inject drugs was significantly associated with higher depressive symptoms and lower family relations reported by themselves as well as their family members. Family relations reported by people who inject drugs and their family members were positively correlated. The findings highlight the need for interventions that address psychological distress and the related challenges faced by family members of people who inject drugs. The article has policy implication which concludes with an argument for developing strategies that enhance the role of families in supporting behavioral change among people who inject drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Perceptions of Family Participation in Intensive Care Unit Rounds and Telemedicine: A Qualitative Assessment.

PubMed

Stelson, Elisabeth A; Carr, Brendan G; Golden, Kate E; Martin, Niels; Richmond, Therese S; Delgado, M Kit; Holena, Daniel N

2016-09-01

Family-centered rounds involve purposeful interactions between patients' families and care providers to refocus the delivery of care on patients' needs. To examine perspectives of patients' family members and health care providers on family participation in rounds in the surgical intensive care unit (ICU) and the potential use of telemedicine to facilitate this process. Patients' family members and surgical ICU care providers were recruited for semistructured interviews exploring stakeholders' perspectives on family participation in ICU rounds and the potential role of telemedicine. Thirty-two interviews were conducted, audio recorded, and transcribed verbatim. Common coding methods were facilitated by using NVivo 10. A mean coding agreement of 97.3% was calculated for 22% of transcripts. Both patients' family members and health care providers described inconsistent practices surrounding family participation in ICU rounds as well as barriers to and facilitators of family participation. Family members identified 3 primary logistical challenges to participation in ICU rounds: distance to hospitals, work/family obligations, and the rounding schedule. Both family members and providers reported receptivity to virtual participation as a potential solution to these challenges. Understanding the barriers to and facilitators of family participation in ICU rounds is key to encouraging adoption of family-centered rounds. For families that live far away or have competing demands, telemedical options may facilitate participation. ©2016 American Association of Critical-Care Nurses.

Family accommodation in obsessive-compulsive disorder: Relation to symptom dimensions, clinical and family characteristics.

PubMed

Albert, Umberto; Bogetto, Filippo; Maina, Giuseppe; Saracco, Paola; Brunatto, Cinthia; Mataix-Cols, David

2010-09-30

Family accommodation is the term used to indicate the process whereby family members of patients with obsessive-compulsive disorder (OCD) assist or participate in the patients' rituals. Family accommodation is a relatively under-researched phenomenon in OCD but an important one because it may be predictive of poor treatment outcome. This study systematically examined several socio-demographic and clinical variables that are associated with family accommodation in a well-characterized sample of adult patients and their healthy family members. Experienced clinicians administered the Family Accommodation Scale (FAS) to 141 psychopathology-free family members cohabiting with 97 patients with OCD. The items of the FAS were first subjected to principal component analysis (PCA) and the resulting domains of family accommodation (Participation, Modification, and Distress and Consequences) introduced as dependent variables in a series of multiple regression models assessing the relationship between family accommodation domains and a wide range of clinical variables, including Axis I and II psychopathology and symptom dimensions derived from the Yale-Brown Obsessive-Compulsive Scale (YBOCS) Symptom Checklist. The results showed that family accommodation was common, with the provision of reassurance, participation in rituals and assisting the patient in avoidance being the most frequent practices (occurring on a daily basis in 47%, 35%, and 43% of family members, respectively). The PCA of the YBOCS Symptom Checklist yielded four symptom dimensions, which were identical to those previously identified in the international literature. Multiple linear regression analyses showed that a higher score on the contamination/washing symptom dimension and a positive family history for an anxiety disorder other than OCD (referring to a family member other than the participant in this study) predicted greater scores on several domains of family accommodation. Our study confirms that family accommodation is frequent and distressing in psychopathology-free family members cohabiting with adult OCD patients. Family accommodation is particularly frequent and distressing when the patient has prominent contamination/washing symptoms and/or when another family member has a history of an anxiety disorder. Such families may be more likely to benefit from family-based interventions but this remains to be tested in controlled trials. Copyright © 2009 Elsevier Ltd. All rights reserved.

Adolescent risk behaviours and mealtime routines: does family meal frequency alter the association between family structure and risk behaviour?

PubMed

Levin, Kate A; Kirby, Joanna; Currie, Candace

2012-02-01

Family structure is associated with a range of adolescent risk behaviours, with those living in both parent families generally faring best. This study describes the association between family structure and adolescent risk behaviours and assesses the role of the family meal. Data from the 2006 Health Behaviour in School-Aged Children survey were modelled using Multilevel Binomial modelling for six risk behaviour outcomes. Significantly more children from 'both parent' families ate a family meal every day and fewer 'hardly ever or never' did. Family structure was associated with boys' and girls' smoking, drinking, cannabis use and having sex and with girls' fighting. Frequency of eating a family meal was associated with a reduced likelihood of all risk behaviours among girls and all but fighting and having sex among boys. Eating a family meal regularly nullified the association between family structure and drinking alcohol for boys and girls and cannabis use for boys and reduced the effect size of alternative family structures on boys having sex and smoking. The family meal, associated with a reduced likelihood of many adolescent risk behaviours, reduces or eliminates the association with family structure and may therefore help to overcome inequalities in adolescent risk behaviours.

Examining the relationship between family meal frequency and individual dietary intake: does family cohesion play a role?

PubMed

Welsh, Ericka M; French, Simone A; Wall, Melanie

2011-01-01

To confirm previously reported associations between family meal frequency and dietary intake, and to examine family cohesion as a potential mediator of this relationship. Cross-sectional observational study. Data collected at baseline via questionnaire. Randomized, controlled household weight gain prevention trial. Participants were 152 adults and 75 adolescents from 90 community households. Family meal frequency assessed with a single question. Perceived family cohesion measured by the Family Adaptability and Cohesion Evaluation Scale-III. Usual intake of targeted food items assessed with modified food frequency questionnaire. Hierarchical linear regression with mediation analysis. Statistical significance set at α-level .05. Family meal frequency was associated with intake of fruits and vegetables in adults, and sweets and sugar-sweetened beverages in adolescents. Family meal frequency was positively correlated with perceived family cohesion (r = 0.41, P < .01). Partial mediation by family cohesion was observed for family meal frequency and sweets intake in adolescents. Results suggest that family cohesion is not a consistent mediator of relationship between family meal frequency and individual dietary intake. Future studies should assess additional plausible mediators of this relationship in order to better understand the effect of family meals on dietary intake. Copyright © 2011 Society for Nutrition Education. Published by Elsevier Inc. All rights reserved.

Family needs of critically ill patients in the emergency department.

PubMed

Hsiao, Ping-Ru; Redley, Bernice; Hsiao, Ya-Chu; Lin, Chun-Chih; Han, Chin-Yen; Lin, Hung-Ru

2017-01-01

Family members' experience a range of physiological, psychological and emotional impacts when accompanying a critically ill relative in the emergency department. Family needs are influenced by their culture and the context of care, and accurate clinician understanding of these needs is essential for patient- and family-centered care delivery. The aim of this study was to describe the needs of Taiwanese family members accompanying critically ill patients in the emergency department while waiting for an inpatient bed and compare these to the perceptions of emergency nurses. A prospective cross-sectional survey was conducted in a large medical center in Taiwan. Data were collected from 150 family members and 150 emergency nurses who completed a Chinese version of the Critical Care Family Needs Inventory. Family members ranked needs related to 'communication with family members,' as most important, followed by 'family member participation in emergency department care', 'family member support' and 'organizational comfort'; rankings were similar to those of emergency nurses. Compared to nurses, family members reported higher scores for the importance of needs related to 'communication with family members' and 'family members' participation in emergency department care'. Family members place greater importance than emergency nurses on the need for effective communication. Copyright © 2016 Elsevier Ltd. All rights reserved.

Family participation in intensive care unit rounds: Comparing family and provider perspectives.

PubMed

Au, Selena S; Roze des Ordons, Amanda; Soo, Andrea; Guienguere, Simon; Stelfox, Henry T

2017-04-01

To describe and compare intensive care unit (ICU) patient family member and provider experiences, preferences, and perceptions of family participation in ICU rounds. Cross-sectional survey of ICU family members and providers of patients admitted to 4 medical-surgical ICUs from September 2014 to March 2015. Surveys were completed by 63 (62%) family members and 258 (43%) providers. Provider respondents included physicians (9%), nurses (56%), respiratory therapists (24%), and other ICU team members (11%). Although 38% of providers estimated only moderate family member interest in participating in rounds, 97% of family members expressed high interest. Family members and providers reported listening (95% vs 96%; P=.594) and sharing information about the patient (82% vs 82%; P=.995) as appropriate roles for family members during rounds, but differed in their perceptions on asking questions (75% vs 86%; P=.043) and participating in decision making (36% vs 59%; P=.003). Compared with family members, providers were more likely to perceive family participation in rounds to cause family stress (7% vs 22%; P=.020) and confusion (0% vs 28%; P<.001). Family members and providers share some perspectives on family participation in ICU rounds although other perspectives are discordant, with implications for communication strategies and collaborative decision making. Copyright © 2016 Elsevier Inc. All rights reserved.

The family empowerment program: an interdisciplinary approach to working with multi-stressed urban families.

PubMed

Cleek, Elizabeth N; Wofsy, Matt; Boyd-Franklin, Nancy; Mundy, Brian; Howell Lcsw, Tamika J

2012-06-01

The family empowerment program (FEP) is a multi-systemic family therapy program that partners multi-stressed families with an interdisciplinary resource team while remaining attached to a "traditional" mental health clinic. The rationale for this model is that far too often, families presenting at community mental health centers struggle with multiple psychosocial forces, for example problems with housing, domestic violence, child care, entitlements, racism, substance abuse, and foster care, as well as chronic medical and psychiatric illnesses, that exacerbate symptoms and impact traditional service delivery and access to effective treatment. Thus, families often experience fragmented care and are involved with multiple systems with contradictory and competing agendas. As a result, services frequently fail to harness the family's inherent strengths. The FEP partners the family with a unified team that includes representatives from Entitlements Services, Family Support and Parent Advocacy, and Clinical Staff from the agency's Outpatient Mental Health Clinic practicing from a strength-based family therapy perspective. The goal of the FEP is to support the family in achieving their goals. This is accomplished through co-construction of a service plan that addresses the family's needs in an efficient and coherent manner-emphasizing family strengths and competencies and supporting family self-sufficiency. © FPI, Inc.

[Comparison of the factors influencing young adolescents' aggression according to family structure].

PubMed

Yun, Eun Kyoung; Shin, Sung Hee

2013-06-01

This cross-sectional study was done to compare factors influencing young adolescents' aggression according to family structure. Participants were 680 young adolescents aged 11 to 15 years (113 in single father families, 136 in single mother families, 49 in grandparent families, and 382 in both-parent families). All measures were self-administered. Data were analyzed using SPSS 18.0 program and factors affecting young adolescents' aggression were analyzed by stepwise multiple regression. Levels of young adolescents' aggression and all variables were significantly different among the four family structure groups. Factors influencing young adolescents' aggression were also different according to these 4 groups. For single father families, depression-anxiety and family hardiness significantly predicted the level of young adolescents' aggression (adjusted R square=.37, p<.001). For single mother families, depression-anxiety, gender, and friends' support significantly predicted the level of young adolescents' aggression (adjusted R square=.58, p<.001). For grandparent families, depression-anxiety and family support significantly predicted the level of young adolescents' aggression (adjusted R square=.58, p<.001). For both-parent families, depression-anxiety, family hardiness, and friends' support significantly predicted the level of young adolescents' aggression (adjusted R square=.48, p<.001). Nurses working with young adolescents should consider family structure-specific factors influencing aggression in this population.

Does public insurance provide better financial protection against rising health care costs for families of children with special health care needs?

PubMed

Yu, Hao; Dick, Andrew W; Szilagyi, Peter G

2008-10-01

Health care costs grew rapidly since 2001, generating substantial economic pressures on families, especially those with children with special health care needs (CSHCN). To examine how the growth of health care costs affected financial burden for families of CSHCN between 2001 and 2004 and to determine the extent to which health insurance coverage protected families of CSHCN against financial burden. In 2001-2004, 5196 families of CSHCN were surveyed by the national Medical Expenditure Panel Survey (MEPS). The main outcome was financial burden, defined as the proportion of family income spent on out-of-pocket (OOP) health care expenditures for all family members, including OOP costs and premiums. Family insurance coverage was classified as: (1) all members publicly insured, (2) all members privately insured, (3) all members uninsured, (4) partial coverage, and (5) a mix of public and private with no uninsured periods. An upward trend in financial burden for families of CSHCN occurred and was associated with growth of economy-wide health care costs. A multivariate analysis indicated that, given the economy-wide increase in medical costs between 2001 and 2004, a family with CSHCN was at increased risk in 2004 for having financial burden exceeding 10% of family income [odds ratio (OR) = 1.39; P < 0.01]. Similar findings were noted for financial burden exceeding 20% of family income. Over 15% of families with public insurance had financial burden exceeding 10% of family income compared with 20% of families with private insurance (P < 0.05; chi2 test). After controlling for covariates, publicly-insured families of CSHCN had significantly lower likelihood of financial burden of >10% or 20% of family income than privately-insured families. Rising health care costs increased financial burden on families of CSHCN in 2001-2004. Public insurance coverage provided better financial protection than private insurance against the rapidly rising health care costs for families of CSHCN.

Family meals then and now: A qualitative investigation of intergenerational transmission of family meal practices in a racially/ethnically diverse and immigrant population.

PubMed

Trofholz, Amanda C; Thao, Mai See; Donley, Mia; Smith, Mireya; Isaac, Hassan; Berge, Jerica M

2018-02-01

Having frequent family meals has consistently been associated with better health outcomes in children/adolescents. It is important to identify how intergenerational transmission of family meal practices occurs to help families benefit from the protective nature of family meals. Limited studies exist that explore the intergenerational transmission of family meal practices, particularly among racially/ethnically diverse and immigrant populations. This study explores how parents describe differences and similarities between meals "then" and "now", lessons they learned as children about family meals, lessons they passed onto their children, the challenges of carrying out family meals, and how families handle the barriers/challenges to intergenerational transmission of family meal practices. The study was conducted with a sample of African American, Native American, Latino, Hmong, Somali, and White families (25/category). Qualitative themes were explored with the overall sample, by race/ethnicity, immigrant status, and by time in the United States (US) as an immigrant. Parents overwhelmingly reported learning as children that family meals were important and conveying this message to their own children. Differences existed among racial/ethnic groups and time in the US as an immigrant. For example, Somali parents frequently endorsed having no challenges with intergenerational transmission of family meal practices. Immigrant parents in the US for a longer period of time were more likely to endorse learning/teaching about family meal importance, that the food eaten now is different than growing up, that a chaotic environment is a challenge to having family meals, and that they accommodate family member's schedules when planning family meals. Results demonstrate that exploring a parent's early family meal experiences may be important when intervening with parents from diverse racial/ethnic and immigrant populations when trying to improve or increase family meal practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Perceived Family Functioning and Family Resources of Hong Kong Families: Implications for Social Work Practice

ERIC Educational Resources Information Center

Ma, Joyce L. C.; Wong, Timothy K. Y.; Lau, Luk King; Pun, Shuk Han

2009-01-01

This article reports the results of a telephone survey (n = 1,015 respondents) that aims to identify the perceived general family functioning and family resources of Hong Kong Chinese families and their linkage to each other in a rapidly transforming society. The perceived general family functioning of the respondents was average, and the five…

FACT SHEET ON WOMEN'S EARNINGS IN POOR FAMILIES.

ERIC Educational Resources Information Center

Women's Bureau (DOL), Washington, DC.

IN 1964 THERE WERE 6.8 MILLION FAMILIES LIVING IN POVERTY. THE INCIDENCE OF POVERTY AMONG FAMILIES WOULD BE GREATER, HOWEVER, IF IT WERE NOT FOR THE CONTRIBUTION MADE BY WORKING WIVES TO FAMILY INCOME. NEARLY 5 MILLION OF THE FAMILIES LIVING IN POVERTY WERE HUSBAND-WIFE FAMILIES. OF ALL HUSBAND-WIFE FAMILIES, ONLY 6 PERCENT WERE POOR IF THE WIFE…

Responses to Children's Media Use in Families with and without Siblings: A Family Development Perspective

ERIC Educational Resources Information Center

Davies, John J.; Gentile, Douglas A.

2012-01-01

Drawing on family development theory, this study provides insight into how family stages with and without siblings are related to media habits and effects. Two national samples (N = 527 and N = 1,257) present a cross-sectional snapshot of media uses in families across three stages of family life: families with preschoolers (2-6 years), with…

Parental Stress, Family-Professional Partnerships, and Family Quality of Life: Families of Children with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Hsiao, Yun-Ju

2013-01-01

The purpose of this study was to investigate the relationship among the quality of life of families that have at least one child with autism spectrum disorder, parental stress level, and partnerships between the family and professionals. Also, parent perceptions of parental stress, family quality of life, and family-professional partnerships were…

Family, employment, and individual resource-based antecedents of maternal work-family enrichment from infancy through middle childhood.

PubMed

Zhou, Nan; Buehler, Cheryl

2016-07-01

This study used data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (N = 1,019) to examine family, employment, and individual antecedents of maternal work-family enrichment from infancy through middle childhood. Work-family conflict and important confounding factors were controlled. From the family domain, higher income-to-needs ratio and social support were associated with higher work-family enrichment. From the employment domain, greater job rewards, benefits of employment for children, and work commitment were associated with higher work-family enrichment. From the individual domain, higher maternal education and extroversion were associated with higher work-family enrichment. No family, employment, and individual characteristics were associated with work-family conflict across time except for partner intimacy. In general, the results supported antecedents of work-family enrichment that supply needed resources. The present study contributed to the literature by identifying antecedents of maternal work-family enrichment across early child developmental stages, which goes beyond examinations of particular life stages and a work-family conflict perspective. Implications for theory and practice are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Social Policies and Families in Stress: Gender and Educational Differences in Work-Family Conflict from a European Perspective.

PubMed

Notten, Natascha; Grunow, Daniela; Verbakel, Ellen

2017-01-01

In modern welfare states, family policies may resolve the tension between employment and care-focused demands. However these policies sometimes have adverse consequences for distinct social groups. This study examined gender and educational differences in working parents' perceived work-family conflict and used a comparative approach to test whether family policies, in particular support for child care and leave from paid work, are capable of reducing work-family conflict as well as the gender and educational gaps in work-family conflict. We use data from the European Social Survey 2010 for 20 countries and 5296 respondents (parents), extended with information on national policies for maternity and parental leave and child care support from the OECD Family Database. Employing multilevel analysis, we find that mothers and the higher educated report most work-family conflict. Policies supporting child care reduce the level of experienced work-family conflict; family leave policy appears to have no alleviating impact on working parents' work-family conflict. Our findings indicate that family policies appear to be unable to reduce the gender gap in conflict perception and even widen the educational gap in work-family conflict.

Income, family characteristics, and physical violence toward children.

PubMed

Berger, Lawrence M

2005-02-01

This paper discusses the ways in which existing microeconomic theories of partner abuse, intra-family bargaining, and distribution of resources within families may contribute to our current understanding of physical child abuse. The empirical implications of this discussion are then tested on data from the 1985 National Family Violence Survey (NFVS) in order to estimate the effects of income, family characteristics, and state characteristics on physical violence toward children. The sample consists of 2,760 families with children from the NFVS. Probit and ordered probit models are used to explore relationships between income, family characteristics, state characteristics, and physical violence toward children among single-parent and two-parent families. In both single-parent and two-parent families, depression, maternal alcohol consumption, and history of family violence affect children's probabilities of being abused. Additionally, income is significantly related to violence toward children in single-parent families. These results reinforce earlier findings that demographic characteristics, maternal depression, maternal alcohol use, and intra-family patterns of violence may largely contribute to child abuse. This research also suggests that income may play a substantially more important role in regard to parental violence in single-parent families than in two-parent families.

The relation between family adversity and social anxiety among adolescents in Taiwan: effects of family function and self-esteem.

PubMed

Yen, Cheng-Fang; Yang, Pinchen; Wu, Yu-Yu; Cheng, Chung-Ping

2013-11-01

This study aimed to examine the relationship between three indicators of family adversity (domestic violence, family substance use, and broken parental marriage) and the severity of social anxiety among adolescents in Taiwan, as well as the mediating effects of perceived family function and self-esteem on that relationship, using structural equation modeling (SEM). A total of 5607 adolescents completed the social anxiety subscale of the Multidimensional Anxiety Scale for Children; the Family APGAR Index; the Rosenberg Self-Esteem Scale; and a questionnaire for domestic violence, family substance use, and broken parental marriage. The relation between family adversity and social anxiety, as well as the mediating effects of family function and self-esteem, was examined using SEM. SEM analysis revealed that all three indicators of family adversity reduced the level of family function, that decreased family function compromised the level of self-esteem, and that a low level of self-esteem further increased the severity of social anxiety. The results indicated that, along with intervening to change family adversity, evaluating and improving adolescents' self-esteem and family function are also important clinical issues when helping adolescents reduce their social anxiety.

Typology of perceived family functioning in an American sample of patients with advanced cancer.

PubMed

Schuler, Tammy A; Zaider, Talia I; Li, Yuelin; Hichenberg, Shira; Masterson, Melissa; Kissane, David W

2014-08-01

Poor family functioning affects psychosocial adjustment and the occurrence of morbidity following bereavement in the context of a family's coping with advanced cancer. Family functioning typologies assist with targeted family-centered assessment and intervention to offset these complications in the palliative care setting. Our objective was to identify the number and nature of potential types in an American palliative care patient sample. Data from patients with advanced cancer (N = 1809) screened for eligibility for a larger randomized clinical trial were used. Cluster analyses determined whether patients could be classified into clinically meaningful and coherent groups, based on similarities in their perceptions of family functioning across the cohesiveness, expressiveness, and conflict resolution subscales of the Family Relations Index. Patients' reports of perceived family functioning yielded a model containing five meaningful family types. Cohesiveness, expressiveness, and conflict resolution appear to be useful dimensions by which to classify patient perceptions of family functioning. "At risk" American families may include those we have called hostile, low-communicating, and less-involved. Such families may benefit from adjuvant family-centered psychosocial services, such as family therapy. Copyright © 2014 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Does TV viewing during family meals make a difference in adolescent substance use?

PubMed

Eisenberg, Marla E; Neumark-Sztainer, Dianne; Feldman, Shira

2009-06-01

Family meals are important to adolescent health, but relatively little is known about TV viewing during family meals. The present paper examines the role that TV viewing during family meals may have on substance use behaviors among adolescents. A diverse sample of 806 Minnesota high school students (mean age 17.2 years) provided survey data in 2003-2004 regarding family meal frequency, substance use behavior and general family connectedness. General linear modeling was used to compare substance use across three family meal/TV categories in a cross-sectional analysis. 28.6% of participants ate regular family meals without TV, and 27.5% had regular family meals while watching TV. Significant differences in cigarette smoking, alcohol and marijuana use were found for females reporting regular family meals versus no regular family meals, but did not differ significantly by TV viewing. No significant differences were found across groups of males. Results from this study indicate that TV viewing during family meals does not appear to attenuate the previously observed protective relationship between family meals and substance use for females. Benefits of family meals may be derived simply from having adolescents at home during mealtimes.

Happy Family Kitchen: A community-based research for enhancing family communication and well-being in Hong Kong.

PubMed

Ho, Henry C Y; Mui, Moses; Wan, Alice; Ng, Yin-Lam; Stewart, Sunita M; Yew, Carol; Lam, Tai Hing; Chan, Sophia S

2016-09-01

Urban families worldwide are often characterized by busy working lives which leave little time for family gatherings and communication. The Happy Family Kitchen project, which emphasized cooking and dining with family members, was conducted in a deprived district in Hong Kong. We hypothesized that the community-based family intervention, derived from a positive psychology framework, can improve family communication, family well-being, and subjective happiness. Twenty-three social service units organized and delivered the intervention programs for 1,419 individuals from 612 families. The core intervention was developed with emphasis on 1 of 5 positive psychology themes: gratitude, flow, happiness, health, and savoring. Intervention outcomes were assessed at preintervention, immediate postintervention, and 6 weeks and 12 weeks postintervention. Results showed that family communication, family well-being, and subjective happiness improved with small effect sizes which were sustained up to 12 weeks. The gratitude intervention improved all of the outcome measures. Qualitative data provided additional evidence for effectiveness with in-depth insights into family dynamics. We concluded that this brief intervention was a low-cost and simple approach to improve family communication and well-being. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Adolescents' perceptions and experiences of family meals.

PubMed

Prior, Amie-Louise; Limbert, Caroline

2013-12-01

Benefits of family meals include diet quality, social interaction and wellbeing, yet previous research indicates only one in four adolescents eats a meal with their family every day. This study identified factors relating to the frequency and importance of family meals. A focus group conducted with seven adolescents was analysed thematically. The themes and findings of past research were used to develop a Family Meals Questionnaire (FMQ), completed by 76 adolescents. Regular engagement in healthy family meals eaten around the table was reported, with the majority of participants reporting that their meals included a variety of foods and portions of vegetables. Frequency of family meals was associated with increased family togetherness for both males and females. The nutritional value of meals was found to be most important to females, whereas the impact of family meals on mood was more salient for males. Findings suggest that the views and behaviour of other family members may influence adolescents' enjoyment and perceptions of the importance of family meals, and therefore impact on their frequency. These findings may inform the development of future interventions aimed at increasing adolescent engagement in family meals by adopting a family systems approach to improve the frequency and experience of family meals.

The role of social support, family identification, and family constraints in predicting posttraumatic stress after cancer.

PubMed

Swartzman, Samantha; Sani, Fabio; Munro, Alastair J

2017-09-01

We compared social support with other potential psychosocial predictors of posttraumatic stress after cancer. These included family identification, or a sense of belonging to and commonality with family members, and family constraints, or the extent to which family members are closed, judgmental, or unreceptive in conversations about cancer. We also tested the hypothesis that family constraints mediate the relationship between family identification and cancer-related posttraumatic stress. We used a cross-sectional design. Surveys were collected from 205 colorectal cancer survivors in Tayside, Scotland. Both family identification and family constraints were stronger independent predictors of posttraumatic stress than social support. In multivariate analyses, social support was not a significant independent predictor of posttraumatic stress. In addition, there was a significant indirect effect of family identification on posttraumatic stress through family constraints. Numerous studies demonstrate a link between social support and posttraumatic stress. However, experiences within the family may be more important in predicting posttraumatic stress after cancer. Furthermore, a sense of belonging to and commonality with the family may reduce the extent to which cancer survivors experience constraints on conversations about cancer; this may, in turn, reduce posttraumatic stress. Copyright © 2016 John Wiley & Sons, Ltd.

Parent-Adolescent Conflict in African American Families.

PubMed

Skinner, Olivenne D; McHale, Susan M

2016-10-01

Parent-adolescent conflict is frequent in families and has implications for youth adjustment and family relationships. Drawing on a family systems perspective, we examined mothers', fathers', and two adolescent-aged siblings' (50.5 % females) reports of parent-adolescent conflict in 187 African American families. Using latent profile analysis in the context of an ethnic homogeneous design, we identified three family types based on levels of and differences between parent and youth conflict reports: low conflict, father high conflict, and younger sibling high conflict. Compared to low conflict families, youth in younger sibling high conflict families reported more depressive symptoms and risky behaviors. The results for parents' acceptance revealed that, in comparison to low conflict families, older siblings in father high conflict families reported lower acceptance from mothers, and mothers in these families reported lower acceptance of their children; further, older siblings in younger sibling high conflict families reported less acceptance from fathers, and fathers in these families reported less acceptance of their children. Results underscore the significance of levels of and both differences between and direction of differences in parents' and youth's reports of their "shared" experiences, as well as the importance of examining the larger family contexts of dyadic parent-relationships.

Family Resilience in the Military

PubMed Central

Meadows, Sarah O.; Beckett, Megan K.; Bowling, Kirby; Golinelli, Daniela; Fisher, Michael P.; Martin, Laurie T.; Meredith, Lisa S.; Osilla, Karen Chan

2016-01-01

Abstract Military life presents a variety of challenges to military families, including frequent separations and relocations as well as the risks that service members face during deployment; however, many families successfully navigate these challenges. Despite a recent emphasis on family resilience, the U.S. Department of Defense (DoD) does not have a standard and universally accepted definition of family resilience. A standard definition is a necessary for DoD to more effectively assess its efforts to sustain and improve family resilience. RAND authors reviewed the literature on family resilience and, in this study, recommend a definition that could be used DoD-wide. The authors also reviewed DoD policies related to family resilience, reviewed models that describe family resilience and identified key family resilience factors, and developed several recommendations for how family-resilience programs and policies could be managed across DoD. PMID:28083409

Topical Review: Integrating Findings on Direct Observation of Family Communication in Studies Comparing Pediatric Chronic Illness and Typically Developing Samples.

PubMed

Murphy, Lexa K; Murray, Caitlin B; Compas, Bruce E

2017-01-01

To review research on observed family communication in families with children with chronic illnesses compared with families with healthy, typically developing children, and to integrate findings utilizing a unifying family communication framework. Topical review of studies that have directly observed family communication in pediatric populations and included a typically developing comparison group. Initial findings from 14 studies with diverse approaches to quantifying observed family communication suggest that families with children with chronic illnesses may demonstrate lower levels of warm and structured communication and higher levels of hostile/intrusive and withdrawn communication compared with families with healthy, typically developing children. An integrative framework of family communication may be used in future studies that examine the occurrence, correlates, and mechanisms of family communication in pediatric populations.

The Family and Addictions: An Introduction.

ERIC Educational Resources Information Center

Lewis, Robert A.

1989-01-01

Discusses issues related to families and addictions in the context of family-related helping professions and addictions counseling. Describes family systems approach to addictions and some family-based addiction interventions. Notes research articles that have made significant contributions to families and addictions field. (Author/CM)

Family breakup and adolescents' psychosocial maladjustment: public health implications of family disruptions.

PubMed

Roustit, Christelle; Chaix, Basile; Chauvin, Pierre

2007-10-01

Recent changes in family structure are associated with an increase in psychosocial maladjustment in adolescents. We examined, from a public health intervention perspective, the association between family breakup and psychosocial maladjustment in adolescents and assessed the mediating role of family-functioning variables. We analyzed data from the Social and Health Survey of Children and Adolescents in Quebec, Montreal, Canada, which was conducted in 1999. Sample-weighted logistic regression analyses were performed to determine the risk of internalizing disorders, externalizing disorders, substance abuse, and alcohol consumption in relation to family breakups and family-functioning variables, after adjusting for socioeconomic factors. All 4 of the indicators of psychosocial maladjustment were significantly associated with family breakup. The association between family breakups and internalizing disorders was mediated by parental psychological distress and low paternal emotional support. Independently, the witnessing of interparental violence was also strongly associated with internalizing disorders. For the other 3 outcomes, that is, externalizing disorders, substance abuse, and alcohol consumption, family breakup and family-functioning variables had independent effects. Family-based interventions and social approaches are complementary support modalities for adolescents experiencing family disruptions.

Family Communication about End-of-Life Decisions and the Enactment of the Decision-Maker Role.

PubMed

Trees, April R; Ohs, Jennifer E; Murray, Meghan C

2017-06-07

End-of-life (EOL) decisions in families are complex and emotional sites of family interaction necessitating family members coordinate roles in the EOL decision-making process. How family members in the United States enact the decision-maker role in EOL decision situations was examined through in-depth interviews with 22 individuals who participated in EOL decision-making for a family member. A number of themes emerged from the data with regard to the enactment of the decision-maker role. Families varied in how decision makers enacted the role in relation to collective family input, with consulting, informing and collaborating as different patterns of behavior. Formal family roles along with gender- and age-based roles shaped who took on the decision-maker role. Additionally, both family members and medical professionals facilitated or undermined the decision-maker's role enactment. Understanding the structure and enactment of the decision-maker role in family interaction provides insight into how individuals and/or family members perform the decision-making role within a cultural context that values autonomy and self-determination in combination with collective family action in EOL decision-making.

Families living with chronic illness: beliefs about illness, family, and health care.

PubMed

Årestedt, Liselott; Benzein, Eva; Persson, Carina

2015-05-01

Beliefs can be described as the lenses through which we view the world. With emerging illness, beliefs about the illness experience become important for nurses to understand to enhance well-being and healing. The aim of this study was to illuminate illness beliefs of families living with chronic illness. A qualitative design was chosen, including repeated narrative research interviews with seven Swedish families living with chronic illness. Hermeneutic analysis was used to interpret the transcribed family interviews. The result described beliefs in families, both within and across families. Both core beliefs and secondary beliefs about illness, family, and health care were revealed. Illness beliefs have importance for how families respond to and manage situations that arise from their encounters with illness. Nurses have to make space for and listen to families' stories of illness to become aware of what beliefs may support and encourage family well-being and healing. The Illness Beliefs Model provides a touchstone whereby nurses can distinguish both individual and shared beliefs within families living with chronic illness and provide ideas for family intervention if needed. © The Author(s) 2015.

Strengths and resources used by Australian and Danish adult patients and their family caregivers during treatment for cancer.

PubMed

Coyne, E; Dieperink, K B; Østergaard, B; Creedy, D K

2017-08-01

Family plays an essential role in supporting the patient with cancer, however, relatively little attention has been given to understanding the strengths and resources of the family unit across different settings and countries. This study aims to investigate the strengths and resources of patients and family members in Australia and Denmark. Using a descriptive, cross-sectional design, 232 patient and family participants from inpatient and outpatient oncology services in Australia and Denmark completed paper based surveys that included the Family Hardiness Index (FHI) and Family Crisis Orientated Personal Evaluation Scales (F-COPES), together with demographic and health information. The family's appraisal of the cancer and ways the family worked together predicted the level of external resources used to manage their circumstances. After a cancer diagnosis patients and family respond in different ways related to their family functioning. There is a need for nurses to work closely with the family to understand their strengths and resources, and tailor support and information for family to promote optimal patient outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Family Cultures in The Context of Migration and Ageing.

PubMed

Albert, Isabelle; Coimbra, Stephanie Barros

2017-06-01

Intergenerational family relations are embedded in family cultures which influence how families regulate their relations over the whole life span with regard to key issues, such as autonomy and relatedness, or support exchange and reciprocity, and which may vary inter- and intraculturally. Migrant families undoubtedly face a special situation as values and expectations from the culture of origin and from the host cultural context might differ. Not much is known yet about how migrant families adapt their family cultures to the host cultural context. The present article will focus on aspects of intergenerational family regulation by taking into account family cultures of migrant compared to non-migrant families in a life span perspective. We will illustrate our theoretical outline by presenting first results from the IRMA-study comparing Luxembourgish and Portuguese immigrant families living in Luxembourg. We focus on issues of family cohesion, enmeshment and normative expectations regarding adult children's support for their ageing parents, by drawing both on quantitative questionnaire as well as qualitative interview data. Implications for the experience of ambivalence and conflicts as well as well-being of family members from both generations will be discussed.

Worker, workplace or families: What influences family focused practices in adult mental health?

PubMed

Maybery, D; Goodyear, M; Reupert, A E; Grant, A

2016-04-01

WHAT IS KNOWN ON THE SUBJECT?: Family focused practice leads to positive outcomes for parents and children. There are barriers and enablers for practitioners being family focused. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Worker skill, knowledge and confidence about family work are the most important factors associated with family focused practices. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Mental health nurses require specific skill training in family focused practices, time to engage with clients on parenting issues and that there are adequate services to refer family members to. Introduction Family focused practice is thought to lead to positive outcomes for all family members. However, there are multiple barriers and enablers in adult mental health services to practitioners undertaking these actions. Aim The aim of this study was to examine the relative importance of worker, workforce and family factors to predict family focused practices (FFPs) in adult mental health services. Method Three hundred and seven adult mental health workers completed a 45 items family focused practice measure of 16 family focused practices. Thesis It was found that worker skill and knowledge about family work and an ability to assess the degree of parental insight into the child's connections to other family members and the community were important predictors of FFP, along with the closely related-worker confidence. While aspects of the worker, workplace and family each contribute to FFPs, this study highlighted the importance of worker skill, knowledge and confidence as central issues for adult mental health workers. Implications for practice Study implications include the need for training in specific FFPs, the provision of time to engage with clients on parenting issues and the need 5 to ensure that there are adequate services for workers to refer family members to. © 2016 John Wiley & Sons Ltd.

Validity and reliability of the personnel version of the Family Empowerment Scale (FES) for the social, health and educational services in Finland.

PubMed

Vuorenmaa, Maaret; Halme, Nina; Åstedt-Kurki, Päivi; Kaunonen, Marja; Perälä, Marja-Leena

2014-04-01

This paper reports a study testing of the validity and reliability of the personnel version of the Family Empowerment Scale in family services in Finland. The role of family services in parental reinforcement is important, given their extensive reach to most families and their aim of promoting family welfare. No instruments applicable to this situation were available in Finland. The Family Empowerment Scale is a widely used instrument that measures parent's empowerment. The personnel version of the Family Empowerment Scale enables an evaluation of the reinforcement of empowerment. This study used a cross-sectional survey design. The Family Empowerment Scale was modified to measure how family services personnel evaluate reinforcement of parental empowerment. In May 2009, a questionnaire was sent to unit heads (n = 457) in public social, health and educational services for families with children aged 0-9 years. The construct, convergent and discriminant validities, reliability and responsiveness of the personnel version of the Family Empowerment Scale were assessed. According to confirmatory factor analysis, the personnel version of the Family Empowerment Scale comprised three subscales (family, service system and community) as in the original Family Empowerment Scale. Confirmed convergent and discriminant validities supported the same construct. The reliability of the personnel version of the Family Empowerment Scale was acceptable. The reinforcement level of parental empowerment was high. Parental empowerment was reinforced most in health and least in educational services. The psychometric properties of the personnel version of the Family Empowerment Scale were acceptable. It can serve as a generic instrument for assessing reinforcement of empowerment in family services in Finland. © 2013 John Wiley & Sons Ltd.

The behavior of Italian family physicians regarding the health problems of women and, in particular, family planning (both contraception and NFP).

PubMed

Girotto, S; Del Zotti, F; Baruchello, M; Gottardi, G; Valente, M; Battaggia, A; Rosa, B; Fedrizzi, P; Campanella, M; Zumerle, M; Bressan, F

1997-01-01

The hospital-centered trend that has dominated medical culture and the management of health care during this entire century has, in the last few years, undergone a reversal in Italy. Conditions in other countries suggest that similar changes have or will become increasingly common. The family physician today manages many of the functions previously handled by hospitals and specialists. In the field of reproductive health, family physicians are responsible not only for diagnosis and treatment, but also for prevention and education. The present study considers this new context with the objective of investigating the knowledge and behavior of Italian family physicians in the field of women's health, with particular regard to family planning (including natural family planning), through (1) a qualitative study (focus groups) of a small group of family physicians and (2) a questionnaire sent to 500 family physicians throughout Italy. The results of the focus group are summarized in the form of obstacles that the family physician finds in providing family planning services and proposals for change. The results indicate that because of their holistic approach, the family physician is an appropriate provider of family planning services although continued use of specialists' services, changes in logistics of the family physicians' practice, increased gender sensitivity, and additional training and information are necessary. The results of the questionnaire (121 responses, 24.2%) indicate that the Italian family physician currently lacks certain important information about family planning and would require logistical support to provide these services but is interested in acquiring information and is an appropriate family planning provider. An additional challenge for encouraging family practitioners to provide natural methods is that they favor a "medical" approach rather than a "behavioral" one in their treatment preferences for several other conditions.

Similarities and differences between families who have frequent and infrequent family meals: A qualitative investigation of low-income and minority households.

PubMed

Berge, Jerica M; Draxten, Michelle; Trofholz, Amanda; Hanson-Bradley, Carrie; Justesen, Kathryn; Slattengren, Andrew

2018-04-01

Numerous quantitative studies have examined the association between family meal frequency and child/adolescent weight and weight-related behaviors. However, limited qualitative research has been conducted to identify mealtime characteristics (e.g., child behavior during meals, rules/expectations, family dynamics) that occur during family meals that may explain why some families engage in frequent family meals and others do not. This is particularly important within racially/ethnically diverse households, as these demographic groups are at higher risk for weight-related problems. The current study aimed to identify similarities and differences in mealtime characteristics between households that have frequent and infrequent family meals within a low-income and minority population. This qualitative study included 118 parents who participated in Family Meals, LIVE!, a mixed-methods, cross-sectional study. Parents (90% female; mean age = 35) were racially/ethnically diverse (62% African American, 19% White, 4% Native American, 4% Asian, 11% Mixed/Other) and from low-income (73% < $35,000/yr.) households. Data were analyzed using inductive content analysis. Results indicated some similar mealtime characteristics (i.e., picky eating, involving family members in meal preparation) between households having frequent and infrequent family meals. Additionally, several differences in mealtime characteristics were identified between households having frequent (i.e., importance of family meals, flexibility in the definition of family meals, family meal rules, no pressure-to-eat feeding practices) versus infrequent family meals (i.e., pressure-to-eat parent feeding practices, family meals are dinner meals only, and difficult meal time behaviors). Study findings may be useful for developing intervention targets for low-income and racially/ethnically diverse households so more families can benefit from the protective nature of family meals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Family presence during trauma activations and medical resuscitations in a pediatric emergency department: an evidence-based practice project.

PubMed

Kingsnorth, Jennifer; O'Connell, Karen; Guzzetta, Cathie E; Edens, Jacki Curreri; Atabaki, Shireen; Mecherikunnel, Anne; Brown, Kathleen

2010-03-01

The existing family presence literature indicates that implementation of a family presence policy can result in positive outcomes. The purpose of our evidence-based practice project was to evaluate a family presence intervention using the 6 A's of the evidence cycle (ask, acquire, appraise, apply, analyze, and adopt/adapt). For step 1 (ask), we propose the following question: Is it feasible to implement a family presence intervention during trauma team activations and medical resuscitations in a pediatric emergency department using national guidelines to ensure appropriate family member behavior and uninterrupted patient care? Regarding steps 2 through 4 (acquire, appraise, and apply), our demonstration project was conducted in a pediatric emergency department during the implementation of a new family presence policy. Our family presence intervention incorporated current appraisal of literature and national guidelines including family screening, family preparation, and use of family presence facilitators. We evaluated whether it was feasible to implement the steps of our intervention and whether the intervention was safe in ensuring uninterrupted patient care. With regard to step 5 (analyze), family presence was evaluated in 106 events, in which 96 families were deemed appropriate and chose to be present. Nearly all families (96%) were screened before entering the room, and all were deemed appropriate candidates. Facilitators guided the family during all events. One family presence event was terminated. In all cases patient care was not interrupted. Regarding step 6 (adopt/adapt), our findings document the feasibility of implementing a family presence intervention in a pediatric emergency department while ensuring uninterrupted patient care. We have adopted family presence as a standard practice. This project can serve as the prototype for others. Copyright (c) 2010 Emergency Nurses Association. Published by Mosby, Inc. All rights reserved.

Family demands, social support and caregiver burden in Taiwanese family caregivers living with mental illness: the role of family caregiver gender.

PubMed

Hsiao, Chiu-Yueh

2010-12-01

The purpose of this study was to assess gender effects on family demands, social support and caregiver burden as well as to examine contributing factors of caregiver burden in caring for family members with mental illness. Providing continued care and support for people with mental illness is demanding and challenging. Findings of earlier caregiving studies on the role of caregiver gender in response to caregiver burden and caregiving-related factors have been inconsistent. Little research has been undertaken to examine gender effect on family demands, social support and caregiver burden in Taiwanese family caregivers of individuals with mental illness. Cross-sectional, descriptive correlation design. Data from 43 families, including at least one male and female family caregiver in each family, were analysed using descriptive statistics, principal component analysis and mixed linear modelling. Demographic data, Perceived Stress Scale, Perceived Social Support and Caregiver Burden Scale-Brief were used to collect data. Female family caregivers perceived less social support and experienced higher degrees of caregiver burden compared with male family caregivers. In contrast, no significant gender effect was associated with family demands. Family caregivers with greater family demands and less social support experienced higher degrees of caregiver burden. The results reinforced those of previously published studies that caregiver burden is highly prevalent among female family caregivers. Caregiver gender appears to be highly valuable for explaining family demands, social support and caregiver burden. Health care professionals should continue to collaborate with family caregivers to assess potential gender effects on available support and design gender-specific interventions to alleviate caregiver burden. © 2010 Blackwell Publishing Ltd.

Correlates and Predictors of Conflict at the End of Life Among Families Enrolled in Hospice.

PubMed

Kramer, Betty J; Boelk, Amy Z

2015-08-01

Despite the palliative care mandate to view family as the unit of care, and the high prevalence and detrimental consequences of conflict at the end of life, little research has been conducted with hospice families to understand what contributes to family conflict. Using a recently generated explanatory matrix of family conflict at the end of life, this study sought to identify the correlates and predictors of family conflict. As part of a larger mixed methods cross-sectional study, a 100-item survey was administered to 161 hospice family caregivers enrolled in a Medicare/Medicaid certified non-profit hospice organization located in the Midwest U.S. Although overall levels of conflict were relatively low, 57% of hospice caregivers reported experiencing some family conflict at the end of life. Contextual variables associated with family conflict included a history of family conflict, female gender, younger caregiver age, presence of children in the home, and less advance care planning discussions. Significant main effects in the prediction of family conflict in the final hierarchical multiple regression model included prior family conflict, caregiver age, caregiver gender, advance care planning discussions, family "coming out of the woodwork," communication constraints, and family members asserting control. The model explained 59% of the variance in family conflict. Results support the multidimensional theoretical model of family conflict specifying the importance of the family context, key conditions that set the stage for conflict, and essential contributing factors. Implications for routine assessment and screening to identify families at risk and recommendations for future research are highlighted. Copyright © 2015 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Mother-Child Discrepancy in Perceived Family Functioning and Adolescent Developmental Outcomes in Families Experiencing Economic Disadvantage in Hong Kong.

PubMed

Leung, Janet T Y; Shek, Daniel T L; Li, Lin

2016-10-01

Though growing attention has been devoted to examining informant discrepancies of family attributes in social science research, studies that examine how interactions between mother-reported and adolescent-reported family functioning predict adolescent developmental outcomes in underprivileged families are severely lacking. The current study investigated the difference between mothers and adolescents in their reports of family functioning, as well as the relationships between mother-reported and adolescent-reported family functioning and adolescent developmental outcomes in a sample of 432 Chinese single-mother families (mean age of adolescents = 13.7 years, 51.2 % girls, mean age of mothers = 43.5 years, 69.9 % divorced) experiencing economic disadvantage in Hong Kong. Polynomial regression analyses were conducted to assess whether discrepancy in family functioning between mother reports and adolescent reports predicted resilience, beliefs in the future, cognitive competence, self-efficacy and self-determination of adolescents. The results indicated that adolescents reported family functioning more negatively than did their mothers. Polynomial regression analyses showed that the interaction term between mothers' reports and adolescents' reports of family functioning predicted adolescent developmental outcomes in Chinese single-mother families living in poverty. Basically, under poor adolescent-reported family functioning, adolescent development would be relatively better if their mothers reported more positive family functioning. In contrast, under good adolescent-reported family functioning, adolescents expressed better developmental outcomes when mothers reported lower levels of family functioning than those mothers who reported higher levels of family functioning. The findings provide insights on how congruency and discrepancy between informant reports of family functioning would influence adolescent development. Theoretical and practical implications of the findings are discussed.

Family Therapy

MedlinePlus

Family therapy Overview Family therapy is a type of psychological counseling (psychotherapy) that can help family members improve communication and resolve conflicts. Family therapy is usually provided by a psychologist, ...

Making time for family meals: Parental influences, home eating environments, barriers and protective factors.

PubMed

Jones, Blake L

2018-04-06

Frequent family mealtimes have been associated with numerous positive dietary, health, and behavioral outcomes for children and families. This review article summarizes some of the beneficial outcomes associated with having frequent family dinners. Current trends in family dinner frequency are discussed in the context of barriers that influence how often families eat dinner together, including time issues, work issues, and distractions in the home environment. Next, several parental influences and home environment factors that promote healthy and consistent family dinners are outlined. Finally, limitations are discussed and a few practical suggestions are mentioned to help encourage families, employers, and policy-makers to make family mealtimes a regular practice for as many families as possible. Copyright © 2018. Published by Elsevier Inc.

Problems with veteran-family communication during operation enduring freedom/operation Iraqi freedom military deployment.

PubMed

Hinojosa, Ramon; Hinojosa, Melanie Sberna; Högnäs, Robin S

2012-02-01

Twenty Reserve component (Army and Marines) and Army National Guard male veterans of Operational Enduring Freedom/Operation Iraqi Freedom discuss their deployment and postdeployment family reintegration experiences. A Grounded Theory approach is used to highlight some of the ways in which family miscommunication during deployment can occur. Communication with civilian family members is affected by the needs of operational security, technical problems with communication tools, miscommunication between family members, or because veterans have "nothing new to say" to family back home. These communication difficulties may lead to an initial gulf of understanding between veterans and family members that can cause family strain during postdeployment family reintegration. We end with a discussion of veteran family reintegration difficulties.

A novel healthy blood pressure phenotype in the Long Life Family Study.

PubMed

Marron, Megan M; Singh, Jatinder; Boudreau, Robert M; Christensen, Kaare; Cosentino, Stephanie; Feitosa, Mary F; Minster, Ryan L; Perls, Thomas; Schupf, Nicole; Sebastiani, Paola; Ukraintseva, Svetlana; Wojczynski, Mary K; Newman, Anne B

2018-01-01

Hypertension tends to run in families and has both genetic and environmental determinants. We assessed the hypothesis that a novel healthy blood pressure (BP) phenotype is also familial and sought to identify its associated factors. We developed a healthy BP phenotype in the Long Life Family Study, a cohort of two-generation families selected for longevity. Participants from the offspring generation (n = 2211, ages 32-88) were classified as having healthy BP if their age-adjusted and sex-adjusted SBP z-score was between -1.5 and -0.5. Offspring on antihypertensive medications were classified as not having healthy BP. Families with at least two offspring (n = 419 families) were defined as meeting the healthy BP phenotype if at least two and at least 50% of their offspring had healthy BP. Among 2211 offspring, 476 (21.5%) met the healthy BP phenotype. When examining the 419 families, only 44 (10.5%) families met the criteria for the healthy BP phenotype. Both offspring and probands from families with healthy BP performed better on neuropsychological tests that place demands on complex attention and executive function when compared with offspring and probands from remaining families. Among families with the healthy BP phenotype compared with families without, a higher proportion of offspring met the American Heart Association definition of ideal cardiovascular health (10.8 versus 3.8%, respectively; driven by BP, smoking status, and BMI components). In this cohort of familial longevity, few families had a novel healthy BP phenotype in multiple members. Families with this healthy BP phenotype may represent a specific pathway to familial longevity.

The role of family meals in the treatment of eating disorders: a scoping review of the literature and implications.

PubMed

Cook-Darzens, Solange

2016-09-01

Family meal research is a fast growing field that has significant implications for the prevention and treatment of eating disorders (ED). Using a scoping review procedure, this article overviewed major historical and clinical trends that have guided the use of family meals or lunch sessions in adolescent ED family therapy over the past 40 years, and synthesized essential findings from current therapeutic family meal research. The relevant body of literature is reported within the framework of three models of family therapy (Maudsley model, family-based treatment, multi-family therapy), with a focus on their specific use of family lunch sessions and related empirical evidence. Although promising, current evidence remains contradictory, tentative and colored by therapists' convictions, resistance and fears. Future research priorities are discussed, including the need for a more direct examination of the impact of the family meal practice on therapeutic change, as well as a better understanding of its active ingredients and of the characteristics of patients/families that may benefit most from it. This review of the literature may help clinicians and family therapists (1) adhere more reliably and confidently to ED-focused treatment protocols that include a strong family meal component, and (2) make more informed decisions regarding the inclusion or exclusion of family meals in their practice. When feasibility or acceptability issues preclude their use, alternatives to family meals are also discussed, including family meal role-plays and drawings, coaching of home-based family meals and manual/DVD-based guidance.