Perceived racial discrimination and mental distress in older Korean Americans: the moderating role of ethnic resources.

OBJECTIVES: To examine associations among perceived racial discrimination, ethnic resources, and mental distress in older Korean Americans. Ethnic resources included ethnic identity (how closely individuals identify themselves with other members of the same ethnic background) and sense of community (individuals' feelings of belonging to their ethnic group). We examined the direct effect of perceived racial discrimination and these ethnic resources, as well as their interactions, hypothesizing that mental distress associated with perceived racial discrimination would be reduced by ethnic resources. DESIGN: Using survey data from the Study of Older Korean Americans (N = 2,150), linear regression models of mental distress were examined for direct and interactive roles of perceived racial discrimination and ethnic resources. RESULTS: Mental distress was directly associated with perceived racial discrimination (B = 1.90, SE = .20, p < .001), ethnic identity (B = -.41, SE = .13, p < .01), and sense of community (B = -.45, SE = .12, p < .001). Perceived racial discrimination interacted significantly with sense of community (B = -1.86, SE = .28, p < .001). Subgroup analyses suggested that in the context of experiencing racial discrimination, a high sense of community can serve as a buffer against mental distress. CONCLUSIONS: Ethnic resources are a benefit in coping with experiences of discrimination. The moderating role of sense of community suggests the value of fostering social capital in ethnic communities to protect and promote older immigrants' mental health.

Intimate Partner Violence Among Hispanic/Latinx and White College Students.

Hispanic/Latinx individuals disproportionately experience intimate partner violence (IPV) compared to their non-Hispanic/Latinx counterparts, and little is known about IPV among college-aged Hispanic/Latinx students. This study examines the rates of IPV victimization and perpetration and their correlates among Hispanic/Latinx and non-Hispanic White college students by analyzing cross-sectional survey data of 3,397 Hispanic/Latinx and White college students enrolled in seven universities. Compared to their White counterparts, Hispanic/Latinx students reported higher rates of IPV victimization and perpetration. Age, gender, drug use, and adverse childhood experience were associated with both IPV victimization and perpetration, while ethnicity was only associated with IPV perpetration. This study's findings highlight the urgent need for more culturally sensitive IPV prevention services and responses to support Hispanic/Latinx college students.

Neighborhood Social Cohesion and the Health of Native Hawaiian and Other Pacific Islander Older Adults.

Native Hawaiian and other Pacific Islander (NHPI) older adults experience various social and health challenges. There is a growing literature linking neighborhood conditions with health, yet few have focused on NHPI older adults. This study examines associations between neighborhood social cohesion and health outcomes (i.e., self-rated health, psychological distress, and memory) in this population. Data from the 2014 Native Hawaiian and Pacific Islander National Health Interview Survey (n=1,045 with respondents aged 50+) were analyzed with logistic regression models. The level of neighborhood social cohesion was determined by responses to items on perceptions of mutual help, dependability, trust, and close relationships within the neighborhood. Higher perceived neighborhood social cohesion was associated with lower odds of having serious psychological distress or memory problems. There was no statistical association of social cohesion with self-rated health. Socially cohesive neighborhoods are important to the health of NHPI. We discuss methods to improve neighborhood social cohesion as a way to promote health equity for NHPI older adults in the United States (U.S.).

The role of self-rated mental health in seeking professional mental health services among older Korean immigrants.

OBJECTIVES: The gap between mental health needs and service use in racial/ethnic minorities continues to be a major public health concern. Focusing on older Korean immigrants, the present study examined linkages among mental distress, self-rated mental health (SRMH), and the use of professional mental health services. We hypothesized that SRMH would play a mediating role in the relationship between mental distress and the use of professional mental health services. METHOD: Using data from the Study of Older Korean Americans (SOKA; N = 2,150, Mean age = 73.4), the direct and indirect effect models were tested. RESULTS: Nearly 30% of the sample fell within the category of experiencing mental distress, but only a small proportion (5.7%) had used professional mental health services. Supporting our hypothesis, the pathway from mental distress to the use of professional mental health services was influenced by an individual's subjective perception of mental health status: the indirect effect of mental distress on service use through SRMH (.04 [.01]) was significant (bias-corrected 95% confidence interval for the indirect effect = .02, .06). CONCLUSION: The findings of this study not only contribute to our understanding of help-seeking processes in a group at high mental health risk but also suggest avenues to promote their use of mental health services.

Examining Housing Environments and Health Status of Older Adults with Physical Disabilities in South Korea.

The present study examined the relationships between housing environments and health and well-being among older adults with physical disabilities in South Korea. Data are from the 2014 National Survey on Persons with Disabilities. We modelled four health and well-being outcomes - perceived stress, depressive symptoms, suicidal ideation, and life satisfaction - by various housing environments among 2,077 older adults with physical disabilities. The results illustrate that home ownership and perceived house accessibility are associated with health and well-being. Findings indicate that efforts to promote the health of older adults with physical disabilities need to be accompanied by improvements in their housing environment.

Regiospecificity of a novel bacterial lipoxygenase from Myxococcus xanthus for polyunsaturated fatty acids.

Lipoxygenase (LOX) is the key enzyme involved in the synthesis of oxylipins as signaling compounds that are important for cell growth and development, inflammation, and pathogenesis in various organisms. The regiospecificity of LOX from Myxococcus xanthus, a gram-negative bacterium, was investigated. The enzyme catalyzed oxygenation at the n-9 position in C20 and C22 polyunsaturated fatty acids (PUFAs) to form 12S- and 14S-hydroxy fatty acids (HFAs), respectively, and oxygenation at the n-6 position in C18 PUFAs to form 13-HFAs. The 12S-form products of C20 and C22 PUFAs by M. xanthus LOX is the first report of bacterial LOXs. The residues involved in regiospecificity were determined to be Thr397, Ala461, and Ile664 by analyzing amino acid alignment and a homology model based on human arachidonate 15-LOX with a sequence identity of 25%. Among these variants, the regiospecificity of the T397Y variant for C20 and C22 PUFAs was changed. This may be because of the reduced size of the substrate-binding pocket by substitution of the smaller Thr to the larger Tyr residue. The T397Y variant catalyzed oxygenation at the n-6 position in C20 and C22 PUFAs to form 15- and 17-hydroperoxy fatty acids, respectively. However, the oxygenation position of T397Y for C18 PUFAs was not changed. The discovery of bacterial LOX with novel regiospecificity will facilitate the biosynthesis of regiospecific­oxygenated signaling compounds.

Death Attitudes Among Middle-Aged Koreans: Role of End-of-Life Care Planning and Death Experiences.

The purpose of this study was to examine factors affecting death attitudes among middle-aged Koreans. In addition, the study explored the interaction effect between knowledge about end-of-life care planning and the experience of death of family or friends on death attitudes. The sample was obtained from a national survey with middle-aged adults in South Korea ( n = 2,026). Multivariate regression analysis revealed significant main effects and an interaction effect between knowledge about end-of-life care planning and the experience of death on death attitudes. Greater knowledge of end-of-life care planning was associated with more positive attitudes toward death; however, the effect was stronger for those who had not experienced the death of family or friends. Being older and having greater life satisfaction were also associated with more positive attitudes toward death. This study suggests that end-of-life education can help middle-aged adults embrace the final stage of life and prepare for their own death.

High-yield production of pure tagatose from fructose by a three-step enzymatic cascade reaction.

OBJECTIVE: To produce tagatose from fructose with a high conversion rate and to establish a high-yield purification method of tagatose from the reaction mixture. RESULTS: Fructose at 1 M (180 g l-1) was converted to 0.8 M (144 g l-1) tagatose by a three-step enzymatic cascade reaction, involving hexokinase, plus ATP, fructose-1,6-biphosphate aldolase, phytase, over 16 h with a productivity of 9 g l-1 h-1. No byproducts were detected. Tagatose was recrystallized from ethanol to a purity of 99.9% and a yield of 96.3%. Overall, tagatose at 99.9% purity was obtained from fructose with a yield of 77%. CONCLUSION: This is the first biotechnological production of tagatose from fructose and the first application of solvent recrystallization for the purification of rare sugars.

Alternative Biotransformation of Retinal to Retinoic Acid or Retinol by an Aldehyde Dehydrogenase from Bacillus cereus.

UNLABELLED: A novel bacterial aldehyde dehydrogenase (ALDH) that converts retinal to retinoic acid was first identified in Bacillus cereus The amino acid sequence of ALDH from B. cereus (BcALDH) was more closely related to mammalian ALDHs than to bacterial ALDHs. This enzyme converted not only small aldehydes to carboxylic acids but also the large aldehyde all-trans-retinal to all-trans-retinoic acid with NAD(P)(+) We newly found that BcALDH and human ALDH (ALDH1A1) could reduce all-trans-retinal to all-trans-retinol with NADPH. The catalytic residues in BcALDH were Glu266 and Cys300, and the cofactor-binding residues were Glu194 and Glu457. The E266A and C300A variants showed no oxidation activity. The E194S and E457V variants showed 15- and 7.5-fold higher catalytic efficiency (kcat/Km) for the reduction of all-trans-retinal than the wild-type enzyme, respectively. The wild-type, E194S variant, and E457V variant enzymes with NAD(+) converted 400 µM all-trans-retinal to 210 µM all-trans-retinoic acid at the same amount for 240 min, while with NADPH, they converted 400 µM all-trans-retinal to 20, 90, and 40 µM all-trans-retinol, respectively. These results indicate that BcALDH and its variants are efficient biocatalysts not only in the conversion of retinal to retinoic acid but also in its conversion to retinol with a cofactor switch and that retinol production can be increased by the variant enzymes. Therefore, BcALDH is a novel bacterial enzyme for the alternative production of retinoic acid and retinol. IMPORTANCE: Although mammalian ALDHs have catalyzed the conversion of retinal to retinoic acid with NAD(P)(+) as a cofactor, a bacterial ALDH involved in the conversion is first characterized. The biotransformation of all-trans-retinal to all-trans-retinoic acid by BcALDH and human ALDH was altered to the biotransformation to all-trans-retinol by a cofactor switch using NADPH. Moreover, the production of all-trans-retinal to all-trans-retinol was changed by mutations at positions 194 and 457 in BcALDH. The alternative biotransformation of retinoids was first performed in the present study. These results will contribute to the biotechnological production of retinoids, including retinoic acid and retinol.

KOREAN AMERICAN PARENTS' PERCEPTIONS OF EFFECTIVE PARENTING STRATEGIES IN THE UNITED STATES.

This study aimed to explore the perceptions of Korean American parents on effective parenting strategies taught in a standardized U.S. parenting program. Participants in the study were interviewed using semi-structured open-ended questions, and audio taped interview data were transcribed and analyzed using content analysis. Themes that emerged were: effective parenting strategies, impact of learning effective parenting strategies on parents, and learning effective parenting strategies: impact on children. Findings indicated that Korean American parents felt the program was based on Western parenting strategies but they were effective. They also believed the program strategies would be useful in regulating their emotions, increasing their abilities to be patient and consistent with their children, and helping them explore issues from their child's perspective, all of which they believed improved their parenting self-efficacy and intimacy with their children. Additionally, parents reported that their children acquired more self-confidence, better self-expression, increased obedience and decreased misbehaviors, and increased emotion regulation and problem solving as a result of their participation in the program. These findings could contribute to develop an effective, culturally and linguistically relevant parenting program for Korean American parents.

Intention to Use Long-Term Care Facilities: Differences beween Korean Pre-elderly and Korean Baby-boomers.

With the rapidly increasing number of older adults, dealing with long-term care (LTC) needs becomes an emerging issue in South Korea. This study aims to examine factors affecting the intention to use longtermcare facilities with two groups of young-old adults: (1) Korean pre-elderly (KPE) and (2) Korean babyboomers (KBB). Guided by Andersen's behavioral model of health service use and prior research, predisposing characters, enabling resources, need factors, availabilities of informal care and self-care activities were used as predictors. In the final analyses, 803 KPE and 966 KBB were included. The results of logistic regression analyses showed different findings in two groups. Age, education, spouse's physicalhealth, and self-care activities for relationship with family and friends are significantly associated with intention to use LTC facilities among KPE. However, income, physical health of respondents, and relationship satisfaction with children are significantly related to intention of use LTC facilities in the group of KBB. This study suggests different LTC needs between KPE and KBB. Health care professionals and policy makers need to consider such differences to provide quality LTC care for them.

Unveiling of novel regio-selective fatty acid double bond hydratases from Lactobacillus acidophilus involved in the selective oxyfunctionalization of mono- and di-hydroxy fatty acids.

The aim of this study is the first time demonstration of cis-12 regio-selective linoleate double-bond hydratase. Hydroxylation of fatty acids, abundant feedstock in nature, is an emerging alternative route for many petroleum replaceable products thorough hydroxy fatty acids, carboxylic acids, and lactones. However, chemical route for selective hydroxylation is still quite challenging owing to low selectivity and many environmental concerns. Hydroxylation of fatty acids by hydroxy fatty acid forming enzymes is an important route for selective biocatalytic oxyfunctionalization of fatty acids. Therefore, novel fatty acid hydroxylation enzymes should be discovered. The two hydratase genes of Lactobacillus acidophilus were identified by genomic analysis, and the expressed two recombinant hydratases were identified as cis-9 and cis-12 double-bond selective linoleate hydratases by in vitro functional validation, including the identification of products and the determination of regio-selectivity, substrate specificity, and kinetic parameters. The two different linoleate hydratases were the involved enzymes in the 10,13-dihydroxyoctadecanoic acid biosynthesis. Linoleate 13-hydratase (LHT-13) selectively converted 10 mM linoleic acid to 13S-hydroxy-9(Z)-octadecenoic acid with high titer (8.1 mM) and yield (81%). Our study will expand knowledge for microbial fatty acid-hydroxylation enzymes and facilitate the designed production of the regio-selective hydroxy fatty acids for useful chemicals from polyunsaturated fatty acid feedstocks.

Biochemical properties of retinoid-converting enzymes and biotechnological production of retinoids.

Retinoids are a class of compounds that are forms of vitamin A and include retinal, retinol, retinoic acid, and retinyl ester. Retinal is involved in visual cycle, retinol has anti-infective, anticancer, antioxidant, and anti-wrinkle functions, and retinoic acid is used to treat acne and cancer. Retinol, retinoic acid, and retinyl ester are used in cosmetic and pharmaceutical industries. In this article, the biochemical properties and active sites and reaction mechanisms of retinoid-converting enzymes in animals and bacteria, including retinol dehydrogenase, alcohol dehydrogenase, aldo-keto reductase, and aldehyde dehydrogenase, are reviewed. The production of retinoids, using retinoid-producing enzymes and metabolically engineered cells, is also described. Uncharacterized bacterial proteins are suggested as retinoid-converting enzymes, and the production of retinoids using metabolically engineered cells is proposed as a feasible method.

An amino acid at position 512 in ß-glucosidase from Clavibacter michiganensis determines the regioselectivity for hydrolyzing gypenoside XVII.

A recombinant ß-glucosidase from Clavibacter michiganensis specifically hydrolyzed the outer and inner glucose linked to the C-3 position in protopanaxadiol (PPD)-type ginsenosides and the C-6 position in protopanaxatriol (PPT)-type ginsenosides except for the hydrolysis of gypenoside LXXV (GypLXXV). The enzyme converted gypenoside XVII (GypXVII) to GypLXXV by hydrolyzing the inner glucose linked to the C-3 position. The substrate-binding residues obtained from the GypXVII-docked homology models of ß-glucosidase from C. michiganensis were replaced with alanine, and the amino acid residue at position 512 was selected because of the changed regioselectivity of W512A. Site-directed mutagenesis for the amino acid residue at position 512 was performed. W512A and W512K hydrolyzed the inner glucose linked to the C-3 position and the outer glucose linked to the C-20 position of GypXVII to produce GypLXXV and F2. W512R hydrolyzed only the outer glucose linked to the C-20 position of GypXVII to produce F2. However, W512E and W512D exhibited no activity for GypXVII. Thus, the amino acid at position 512 is a critical residue to determine the regioselectivity for the hydrolysis of GypXVII. These wild-type and variant enzymes produced diverse ginsenosides, including GypXVII, GypLXXV, F2, and compound K, from ginsenoside Rb1. To the best of our knowledge, this is the first report of the alteration of regioselectivity on ginsenoside hydrolysis by protein engineering.

Characterization of an omega-6 linoleate lipoxygenase from Burkholderia thailandensis and its application in the production of 13-hydroxyoctadecadienoic acid.

A recombinant putative lipoxygenase from Burkholderia thailandensis with a specific activity of 26.4 U mg(-1) was purified using HisTrap affinity chromatography. The native enzyme was a 75-kDa dimer with a molecular mass of 150 kDa. The enzyme activity and catalytic efficiency (k cat/K m) were the highest for linoleic acid (k cat of 93.7 s(-1) and K m of 41.5 µM), followed by arachidonic acid, α-linolenic acid, and γ-linolenic acid. The enzyme was identified as an omega-6 linoleate lipoxygenase (or a linoleate 13S-lipoxygenase) based on genetic and HPLC analyses as well as substrate specificity. The reaction conditions for the enzymatic production of 13-hydroxy-9,11(Z,E)-octadecadienoic acid (13-HODE) were optimal at pH 7.5, 25 °C, 20 g l(-1) linoleic acid, 2.5 g l(-1) enzyme, 0.1 mM Cu(2+), and 6% (v/v) methanol. Under these conditions, linoleate 13-lipoxygenase from B. thailandensis produced 20.8 g l(-1) 13-HODE (70.2 mM) from 20 g l(-1) linoleic acid (71.3 mM) for 120 min, with a molar conversion yield of 98.5% and productivity of 10.4 g l(-1) h(-1). The molar conversion yield and productivity of 13-HODE obtained using B. thailandensis lipoxygenase were 151 and 158% higher, respectively, than those obtained using commercial soybean lipoxygenase under the optimum conditions for each enzyme at the same concentrations of substrate and enzyme.

Characterization of alcohol dehydrogenase from Kangiella koreensis and its application to production of all-trans-retinol.

A recombinant alcohol dehydrogenase (ADH) from Kangiella koreensis was purified as a 40 kDa dimer with a specific activity of 21.3 nmol min(-1) mg(-1), a K m of 1.8 µM, and a k cat of 1.7 min(-1) for all-trans-retinal using NADH as cofactor. The enzyme showed activity for all-trans-retinol using NAD (+) as a cofactor. The reaction conditions for all-trans-retinol production were optimal at pH 6.5 and 60 °C, 2 g enzyme l(-1), and 2,200 mg all-trans-retinal l(-1) in the presence of 5% (v/v) methanol, 1% (w/v) hydroquinone, and 10 mM NADH. Under optimized conditions, the ADH produced 600 mg all-trans-retinol l(-1) after 3 h, with a conversion yield of 27.3% (w/w) and a productivity of 200 mg l(-1) h(-1). This is the first report of the characterization of a bacterial ADH for all-trans-retinal and the biotechnological production of all-trans-retinol using ADH.

Characterization of a F280N variant of L-arabinose isomerase from Geobacillus thermodenitrificans identified as a D-galactose isomerase.

The double-site variant (C450S-N475K) L-arabinose isomerase (L-AI) from Geobacillus thermodenitrificans catalyzes the isomerization of D-galactose to D-tagatose, a functional sweetener. Using a substrate-docking homology model, the residues near to D-galactose O6 were identified as Met186, Phe280, and Ile371. Several variants obtained by site-directed mutagenesis of these three residues were analyzed, and a triple-site (F280N) variant enzyme exhibited the highest activity for D-galactose isomerization. The k cat/K m of the triple-site variant enzyme for D-galactose was 2.1-fold higher than for L-arabinose, whereas the k cat/K m of the double-site variant enzyme for L-arabinose was 43.9-fold higher than for D-galactose. These results suggest that the triple-site variant enzyme is a D-galactose isomerase. The conversion rate of D-galactose to D-tagatose by the triple-site variant enzyme was approximately 3-fold higher than that of the double-site variant enzyme for 30 min. However, the conversion yields of L-arabinose to L-ribulose by the triple-site and double-site variant enzymes were 10.6 and 16.0 % after 20 min, respectively. The triple-site variant enzyme exhibited increased specific activity, turnover number, catalytic efficiency, and conversion rate for D-galactose isomerization compared to the double-site variant enzyme. Therefore, the amino acid at position 280 determines the substrate specificity for D-galactose and L-arabinose, and the triple-site variant enzyme has the potential to produce D-tagatose on an industrial scale.

Expression, crystallization and preliminary X-ray crystallographic analysis of cellobiose 2-epimerase from Dictyoglomus turgidum DSM 6724.

Cellobiose 2-epimerase epimerizes and isomerizes ß-1,4- and α-1,4-gluco-oligosaccharides. N-Acyl-D-glucosamine 2-epimerase (DT_epimerase) from Dictyoglomus turgidum has an unusually high catalytic activity towards its substrate cellobiose. DT_epimerase was expressed, purified and crystallized. Crystals were obtained of both His-tagged DT_epimerase and untagged DT_epimerase. The crystals of His-tagged DT_epimerase diffracted to 2.6 Šresolution and belonged to the monoclinic space group P21, with unit-cell parameters a=63.9, b=85.1, c=79.8 Å, ß=110.8°. With a Matthews coefficient VM of 2.18 Å3 Da(-1), two protomers were expected to be present in the asymmetric unit with a solvent content of 43.74%. The crystals of untagged DT_epimerase diffracted to 1.85 Šresolution and belonged to the orthorhombic space group P212121, with unit-cell parameters a=55.9, b=80.0, c=93.7 Å. One protomer in the asymmetric unit was expected, with a corresponding VM of 2.26 Å3 Da(-1) and a solvent content of 45.6%.

Expression, crystallization and preliminary X-ray crystallographic analysis of alcohol dehydrogenase (ADH) from Kangiella koreensis.

Alcohol dehydrogenases (ADHs) are a group of dehydrogenase enzymes that facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of NAD(+) to NADH. In bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD(+). The adh gene from Kangiella koreensis was cloned and the protein (KkADH) was expressed, purified and crystallized. A KkADH crystal diffracted to 2.5 Šresolution and belonged to the monoclinic space group P2(1), with unit-cell parameters a = 94.1, b = 80.9, c = 115.6 Å, ß = 111.9°. Four monomers were present in the asymmetric unit, with a corresponding VM of 2.55 Å(3) Da(-1) and a solvent content of 51.8%.

Health disparities among childrearing women with disabilities.

This study examines leading health indicators for childrearing women with disabilities, including health-related quality of life, chronic health conditions, adverse and preventive health behaviors, health care access, and social and emotional support. The study analyzes aggregated data from the Washington State Behavioral Risk Factor Surveillance System (n = 28,629). The weighted prevalence of key health indicators of childrearing women with disabilities (aged 18-59) are compared with childrearing women without disabilities. A series of adjusted logistic regression analyses are applied, controlling for confounding variables. When compared to childrearing women without disabilities, childrearing women with disabilities are less likely to have a partner or spouse, report lower income and education levels and are older. Childrearing women with disabilities, compared to childrearing women without disabilities, report significantly lower health-related quality of life including poor general health (adjusted odds ratio[AOR] = 6.85; p < .001), frequent mental distress (AOR = 4.02; p < .001), and frequent poor physical health (AOR = 9.34; p < .001); higher prevalence of chronic health conditions, including arthritis, cardiovascular diseases, diabetes, asthma, high blood pressure and cholesterol, and obesity (the range of AORs = 1.59 to 5.65; p < .001); higher prevalence of adverse health behaviors including smoking (AOR = 2.14; p < .001) and lack of exercise (AOR = 1.61; p < .001); more financial barriers to health care (AOR = 2.11; p < .001) and lack of social and emotional support (AOR = 2.05; p < .001) while controlling for age, education, income, and relationship status. Based on population level data, the study reveals that childrearing women with disabilities experience elevated risks of health disparities across many key health indicators, many of which are preventable and modifiable. These findings underscore the importance of identifying contributing factors and developing interventions to improve the health and quality of life of childrearing women with disabilities.