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1.
Aging Ment Health ; 28(1): 54-61, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37227056

RESUMO

OBJECTIVES: Prior research into the factors linked to mental health of caregivers of older adults have largely focused on individual- or household-level characteristics, but neighborhood supports and stressors may also matter for caregiver mental health. The current study fills this knowledge gap by examining the association of neighborhood social cohesion and disorder and depressive symptoms among spousal caregivers. METHOD: We used data from the 2006 to 2016 waves of the Health and Retirement Study, which include 2,322 spousal caregivers. Negative binomial regression models were estimated to examine the association of perceived neighborhood social cohesion and disorder with depressive symptoms. RESULTS: A higher level of perceived neighborhood social cohesion was associated with fewer depressive symptoms (b = -0.06, 95% CI: -0.10, -0.02). On the other hand, greater perceived neighborhood disorder was associated with more symptoms (b = 0.04, 95% CI: 0.01, 0.08). The association of perceived social cohesion with depressive symptoms remained even after controlling for perceived disorder, but neighborhood disorder was no longer associated with depressive symptoms after accounting for reported neighborhood social cohesion. CONCLUSIONS: This study suggests neighborhood supports and stressors matter for caregiver well-being. Neighborhood-based social support may be particularly important for caregivers as they navigate the challenges caregiving for an aging spouse can bring. Future studies should determine if enhancing positive characteristics of the neighborhood promotes well-being of spousal caregivers.


Assuntos
Cuidadores , Depressão , Humanos , Idoso , Depressão/epidemiologia , Depressão/psicologia , Coesão Social , Apoio Social , Saúde Mental , Características de Residência
2.
Public Health Nutr ; 24(7): 1638-1647, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33557974

RESUMO

OBJECTIVE: A suboptimal diet and nutritional deficiencies can have important influences on health with significant impact among older adults. This study aims to assess the presence of suboptimal dietary intake among older Americans and identify risk and protective factors influencing diet quality. DESIGN: Cross-sectional secondary analysis. SETTING: USA. PARTICIPANTS: A nationally representative sample of 5614 community-dwelling older adults over age 54 in the Health and Retirement Study - Health Care and Nutrition Survey. RESULTS: Overall, only 10·7 % of respondents had a good quality diet (Healthy Eating Index score 81 and above); the majority had diets considered poor or needing improvement. Less than 50 % of respondents met dietary guidelines and nutritional goals for most individual food groups and nutrients. Respondents with low socio-economic status, fewer psychosocial resources and those who had limited access to healthy food outlets were more likely to have a diet of suboptimal quality. CONCLUSIONS: Efforts to remove identified barriers that put older adults at risk for poor nutrition and to provide resources that increase access to healthy food should be made to encourage healthy eating and enhance diet quality.


Assuntos
Dieta , Ingestão de Energia , Idoso , Estudos Transversais , Ingestão de Alimentos , Alimentos , Humanos , Pessoa de Meia-Idade , Estados Unidos
3.
J Urban Health ; 97(4): 471-485, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32601773

RESUMO

This study aims to identify age-friendly community features that are associated with better health for older adults. This cross-sectional study utilized the 2015 AARP Age-Friendly Communities (AFC) Survey, which includes 66 home and community features that fall within the eight domains specified by the World Health Organization (WHO)'s age-friendly cities guidelines. Two measures of health (self-rated health and functional limitations) were examined using multi-level linear and logistic regressions. Both a greater perceived availability of age-friendly features in communities and a good person-environment fit were associated with better self-rated health and a lower likelihood of reporting functional limitations. The domains of outdoor spaces and buildings, transportation, and social participation and inclusion were consistently associated with these outcomes. Promoting age-friendliness in outdoor spaces and buildings, transportation, and social participation and inclusion domains by providing green spaces, neighborhood safety programs, transportation options, and social opportunities may be the most effective way to support healthy and active aging.


Assuntos
Autoavaliação Diagnóstica , Características de Residência , Idoso , Idoso de 80 Anos ou mais , Cidades , Estudos Transversais , Feminino , Humanos , Masculino , Características de Residência/estatística & dados numéricos , Autorrelato
4.
Public Health Nutr ; 23(18): 3315-3323, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32792025

RESUMO

OBJECTIVE: A social network is a valuable resource in later life. Therefore, the current study aims to investigate whether social networks within homes and neighbourhoods are associated with older adults' daily fruit and vegetable consumption. DESIGN: Cross-sectional secondary data analysis. SETTING: USA. PARTICIPANTS: A nationally representative sample of 6865 community-dwelling older adults over age 53 in the Health and Retirement Study - Health Care and Nutrition Survey. RESULTS: Older adults who lived alone with no children or friends nearby had the lowest fruit and vegetable consumption. However, the daily fruit and vegetable consumption of respondents who lived alone and had children or friends nearby or those who lived with someone and had no children or friends nearby was not statistically different from those who lived with someone and had children or friends nearby. This suggests that having a social network either at home or in the neighbourhood complements the absence of living with someone or having children or friends nearby and attenuates the negative association between limited social networks and daily fruit and vegetable consumption. A greater decrease in the number of fruits and vegetables consumed was observed among men when they lived alone with no children or friends nearby. CONCLUSIONS: Special attention should be given to older adults with limited social networks, especially older adults living alone with no children or friends nearby. Provision of help with grocery shopping and meal preparation as well as social support networks and more opportunities that can improve social engagement appear to be necessary.


Assuntos
Comportamento Alimentar , Frutas , Características de Residência , Rede Social , Verduras , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Dieta , Dieta Saudável , Características da Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Apoio Social , Fatores Socioeconômicos , Estados Unidos
5.
J Gerontol Soc Work ; 61(8): 792-816, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30395791

RESUMO

The purpose of this study was to evaluate the feasibility and outcomes of the Engaged4Life program, an intervention to encourage inactive community-dwelling older adults to embed physical activity, cognitive activity, and social interaction into their everyday lives in contexts that are personally meaningful and natural for them. Fifteen participants were randomized to the intervention group (technology-assisted self-monitoring of daily activity via pedometers and daily tablet-based surveys; psychoeducation + goal-setting via a 3-hour workshop; and peer mentoring via phone 2×/week for 2.5 weeks) and 15 to the control (technology-assisted self-monitoring only). Recruitment was shown to be feasible and efficient, but not able to reach the target for men. Retention rate was 83% and participants manifested high adherence and engagement with the intervention. Though this pilot trial was not powered to demonstrate significant differences between groups, daily steps increased by 431 (11% increase) from baseline to Week 4 for the intervention (p < .05), but decreased by 458 for the control, for a net difference of 889 steps (p < .05). Findings were sustained at Week 8 (p < .01). In a future trial, difficulties in recruiting men, barriers due to the technology-intensive design, and the optimization of secondary outcome measures should be addressed.


Assuntos
Atividades Cotidianas/psicologia , Promoção da Saúde/normas , Idoso , Idoso de 80 Anos ou mais , Boston , Distribuição de Qui-Quadrado , Computadores de Mão , Exercício Físico/psicologia , Feminino , Promoção da Saúde/métodos , Humanos , Masculino , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Projetos Piloto , Avaliação de Programas e Projetos de Saúde/métodos , Autoeficácia , Inquéritos e Questionários
6.
Bioengineering (Basel) ; 11(4)2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38671801

RESUMO

XRD diffraction and IR absorption were investigated for raw loess powder and heat-treated loess powder. Raw loess retains its useful minerals, but loses their beneficial properties when calcined at 850 °C and 1050 °C. To utilize the useful minerals, loess balls were made using a low-temperature wet-drying method. The radiant energy and transmittance were measured for the loess balls. Far-infrared ray (FIR) emitted from loess bio-balls is selectively absorbed as higher vibrational energy by water molecules. FIR can raise the body's core temperature, thereby improving blood flow through the body's thermoregulatory mechanism. In an exploratory study with 40 participants, when the set temperature of the loess ball mat was increased from 25 °C to 50 °C, blood flow increased by 39.01%, from 37.48 mL/min to 52.11 mL/min, in the left middle finger; in addition, it increased by 39.62%, from 37.15 mL/min to 51.87 mL/min, in the right middle finger. The FIR emitted from loess balls can be widely applied, in various forms, to diseases related to blood flow, such as cold hands and feet, diabetic foot, muscle pain, and menstrual pain.

7.
J Immigr Minor Health ; 25(3): 608-615, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36401712

RESUMO

Guided by the theories of social capital and stress-buffering, we examined how the association between low acculturation and poor mental health among older immigrants would be modified by social capital in ethnic communities (social cohesion, social engagement, perceived ethnic density, and the quality of social interaction). Using data from the Study of Older Korean Americans (N = 2,150, Mean age = 73.4), direct and interactive effect models were examined. Lower acculturation was associated with a greater level of psychological distress, and their link was modified by social cohesion (ß = .19, p < .01) and negative social interactions (ß = - .97, p < .01). Findings suggest that the mental health risk associated with low acculturation could be intensified when older immigrants perceive low sense of cohesion in their ethnic communities or have negative interactions with ethnic community members.


Assuntos
Aculturação , Emigrantes e Imigrantes , Angústia Psicológica , Capital Social , Idoso , Humanos , Asiático/etnologia , Asiático/psicologia , Emigrantes e Imigrantes/psicologia , Saúde Mental/etnologia , Estados Unidos , Coesão Social/etnologia
8.
Gerontologist ; 62(1): 46-55, 2022 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-34043782

RESUMO

BACKGROUND AND OBJECTIVES: Promoting age-friendliness of communities and supporting aging in place (AIP) are of great importance. Based on processes of belonging and agency, which suggest that person-environment interactions influence residents' evaluations and behaviors related to the environment, this study aims to examine the interrelationship between the availability of age-friendly features, perceived age-friendliness of community, and intention toward AIP. RESEARCH DESIGN AND METHODS: This study used the 2015 AARP Age-Friendly Community Survey, which includes 66 home and neighborhood features under the 8 domains specified by the World Health Organization's Age-Friendly Cities Guidelines. A series of regression and mediational analyses were conducted to test hypotheses. RESULTS: Overall, a greater availability of age-friendly features was positively associated with perceived age-friendliness of community and AIP intention. The relationship between age-friendly features and AIP intention was mediated by perceived age-friendliness of community (50.3%-96% of the total effects). When perceived age-friendliness of community was introduced to models, the direct effects of housing, outdoor spaces and buildings, and transportation domains remained significant. DISCUSSION AND IMPLICATIONS: Findings suggest that a greater availability of age-friendly features influences older adults' perception on their community, leading to the development of a desire to age in place, supporting processes of belonging and agency. Domains of housing, outdoor spaces and buildings, and transportation may be the most important features in promoting age-friendliness of community and the key determinants of AIP. Policymakers and practitioners may need to prioritize promoting an age-friendly built environment before the social environment in building age-friendly communities.


Assuntos
Vida Independente , Intenção , Idoso , Envelhecimento , Humanos , Características de Residência , Meio Social
9.
Prev Med Rep ; 29: 101912, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35911578

RESUMO

Food insecurity, reflecting a household's low ability to purchase healthy food, is a public health concern that is associated with poor diet and obesity. Poor food environments, characterized as a neighborhood with low access to healthy, affordable food, may amplify the negative impact of food insecurity on diet and obesity. This study aims to investigate whether food insecurity and food environments are jointly associated with an increased risk of poor diet quality and obesity. We used data from a nationally representative sample of community-dwelling older adults in the Health and Retirement Study Health Care and Nutrition Survey and the National Neighborhood Data Archive to investigate the role of household and neighborhood characteristics on diet and obesity. Weighted regression models were estimated to examine the relationship between food insecurity and food environments as well as their interaction with diet quality and obesity. Food insecure respondents had lower Healthy Eating Index scores and were more likely to be obese than food secure respondents. Living in a poor food environment was associated with lower Healthy Eating Index scores, but not with obesity. We did not find any interaction between food insecurity and food environment in determining either healthy eating or obesity. Reducing food insecurity and increasing access to healthy food environments may encourage healthier eating among older adults, while alleviating food-related hardship may also reduce their obesity risk.

10.
J Aging Health ; 34(4-5): 539-549, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34779298

RESUMO

Objectives: Using comprehensive measures of biological risk, this study aims to investigate the relationship between intake of individual dietary components, overall diet quality, and biological dysregulation. Methods: We analyzed nationally representative data from 3734 older adults who participated in the Health and Retirement Study Venous Blood Study in 2016 and Health Care and Nutrition Survey in 2013. Results: Eleven out of 13 individual dietary components were associated with lower biological risk. Respondents with poor/suboptimal quality diet had higher biological risk than those with good quality diet. Discussion: Findings from this study emphasize the importance of healthy eating in improving health of older adults. Encouraging intake of fruits, greens and beans, whole grains, and fatty acids, while limiting consumption of sodium, added sugar, and saturated fat would improve overall diet quality and contribute to the prevention of chronic diseases and morbidity.


Assuntos
Dieta , Ingestão de Energia , Idoso , Dieta Saudável , Frutas , Humanos , Inquéritos Nutricionais , Estados Unidos
11.
J Korean Med Sci ; 26(6): 814-23, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21655070

RESUMO

The influence of spinal cord injury (SCI) on protein expression in the rat urinary bladder was assessed by proteomic analysis at different time intervals post-injury. After contusion SCI between T9 and T10, bladder tissues were processed by 2-DE and MALDI-TOF/MS at 6 hr to 28 days after SCI to identify proteins involved in the healing process of SCI-induced neurogenic bladder. Approximately 1,000 spots from the bladder of SCI and sham groups were visualized and identified. At one day after SCI, the expression levels of three protein were increased, and seven spots were down-regulated, including heat shock protein 27 (Hsp27) and heat shock protein 20 (Hsp20). Fifteen spots such as S100-A11 were differentially expressed seven days post-injury, and seven proteins including transgelin had altered expression patterns 28 days after injury. Of the proteins with altered expression levels, transgelin, S100-A11, Hsp27 and Hsp20 were continuously and variably expressed throughout the entire post-SCI recovery of the bladder. The identified proteins at each time point belong to eight functional categories. The altered expression patterns identified by 2-DE of transgelin and S100-A11 were verified by Western blot. Transgelin and protein S100-A11 may be candidates for protein biomarkers in the bladder healing process after SCI.


Assuntos
Proteoma/biossíntese , Traumatismos da Medula Espinal/metabolismo , Bexiga Urinária/metabolismo , Cicatrização , Animais , Biomarcadores/metabolismo , Eletroforese em Gel Bidimensional , Feminino , Proteínas de Choque Térmico HSP20/metabolismo , Proteínas de Choque Térmico HSP27/metabolismo , Proteínas dos Microfilamentos/metabolismo , Proteínas Musculares/metabolismo , Proteômica , Ratos , Ratos Sprague-Dawley , Proteínas S100/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Traumatismos da Medula Espinal/patologia
12.
Seniors Hous Care J ; 27(1): 51-61, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31929851

RESUMO

THE PROBLEM: The availability and use of certain services that can compensate for older adults' decreased abilities and capabilities may help them maintain their independence and improve their psychological well-being. Therefore, this study investigated whether service availability and service use were associated with the psychological well-being of residents of residential care facilities and nursing homes. THE RESOLUTION: Residents who used services that provide help with activities of daily living and instrumental activities of daily living were more likely to report a worse mood, poor psychological health, and low self-efficacy compared with those living in facilities where the services were not available. On the other hand, older residents who used social and wellness-related services were more likely to have a better mood, good psychological health, and high self-efficacy. TIPS FOR SUCCESS: Senior living facilities should consider providing more social and wellness-related services and encourage residents' use of such services to improve their psychological well-being.

13.
Gerontologist ; 58(1): 196-206, 2018 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-28082279

RESUMO

PURPOSE OF THE STUDY: We aimed to investigate the interactive effects of perceived neighborhood safety and social cohesion on the psychological health of older adults with and without functional impairments. DESIGN AND METHODS: This cross-sectional study included 13,897 community-dwelling older adults (aged 65 years and older) from the 2011-2012 California Health Interview Survey (CHIS). Hypotheses were tested using weighted moderated ordinary least squared regression analysis. RESULTS: Perceived neighborhood safety was significantly associated with psychological health regardless of respondents' physical functioning, although the effect was greater among older adults with functional limitations. Perceived social cohesion, however, was only significantly related to psychological health among those with functional limitations. Among physically impaired respondents, social cohesion buffered the ill-effect of an unsafe neighborhood on psychological health. IMPLICATIONS: Findings suggest that efforts to promote perceived neighborhood safety and social cohesion are essential to the well-being of older adults. Special attention should be paid to older adults with functional limitations, who appear to be more vulnerable to the negative effects of neighborhood environments.


Assuntos
Vida Independente , Relações Interpessoais , Saúde Mental , Características de Residência , Segurança , Apoio Social , Idoso , Estudos Transversais , Pessoas com Deficiência/psicologia , Saúde Ambiental , Feminino , Disparidades nos Níveis de Saúde , Humanos , Vida Independente/psicologia , Vida Independente/estatística & dados numéricos , Masculino , Fatores Socioeconômicos , Estados Unidos/epidemiologia
14.
J Evid Inf Soc Work ; 15(4): 473-480, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29578835

RESUMO

Established in 2011, the Center for Social Innovation at Boston College has focused on fostering "effective, sustainable social innovations that enhance social justice." the Center is committed to building research evidence that is used for changing practice and works to disseminate findings through a three-channel approach: traditional research publications, convening of practitioners, and through use of media outlets.


Assuntos
Pesquisa/organização & administração , Serviço Social/educação , Serviço Social/organização & administração , Universidades/organização & administração , Boston , Fortalecimento Institucional/organização & administração , Relações Comunidade-Instituição , Humanos , Liderança , Inovação Organizacional , Publicações Periódicas como Assunto
16.
Artigo em Inglês | MEDLINE | ID: mdl-22421644

RESUMO

BACKGROUND: As the demand for noninvasive procedures for skin rejuvenation is increasing, combined diode laser and radiofrequency and combined infrared and radiofrequency devices have recently emerged. AIM: To compare Polaris WRA(TM), a combination device of diode light and RF, and ReFirme ST(TM), a combination device of infrared and bipolar RF, in terms of safety and efficacy on skin rejuvenation. METHODS: Fourteen Korean volunteers of skin type II-IV, with facial laxity and periorbital rhytids, received three treatments at 3-week intervals with combined diode laser and bipolar radiofrequency (laser fluence 30 J/cm2, RF fluence 90 J/cm3) on the right half of their faces and combined infrared light and bipolar radiofrequency (RF fluence 120 J/cm3) on the left half of their faces. Clinical photos of front and bilateral sides of the subjects' faces were taken at baseline and at 6, 9, 12 weeks after the treatment initiation. The investigators' and the subjects' global assessments were performed. RESULTS: There is no statistically significant difference in the overall outcome between Polaris WRA(TM) and Refirme ST(TM) based on pre- and post-treatment objective measurements. Polaris WRA(TM) was more effective than Refirme ST(TM) at reducing wrinkles when therapeutic results of the two appliances were compared based on the patient satisfaction measurements. After the treatment with both instruments, histological increase in the production and rearrangement of collagen fibers at the dermal layer was observed. The density of the collagen fibers was more increased with the Polaris WRA(TM)-treated facial area than that of Refirme ST(TM). Treatment was generally well tolerated, and there was no serious complication. CONCLUSION: In this study, both the lasers appeared to be safe, and effective methods for treating skin laxity and facial wrinkles. Combined diode laser and radiofrequency was more effective than combined infrared and radiofrequency at reducing wrinkles and pores when the therapeutic results of both the appliances were compared.


Assuntos
Técnicas Cosméticas/instrumentação , Raios Infravermelhos/uso terapêutico , Lasers Semicondutores/uso terapêutico , Terapia por Radiofrequência , Rejuvenescimento , Adulto , Biópsia , Face/patologia , Feminino , Humanos , Raios Infravermelhos/efeitos adversos , Lasers Semicondutores/efeitos adversos , Pessoa de Meia-Idade , Satisfação do Paciente , Ondas de Rádio/efeitos adversos , Envelhecimento da Pele/patologia
17.
Ann Dermatol ; 23 Suppl 1: S119-22, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22028557

RESUMO

Familial cutaneous collagenoma is a rare hereditary disease that is inherited in an autosomal dominant pattern. It is characterized by early onset of multiple, skin-colored, sometimes hypopigmented cutaneous nodules, which initially show a symmetrical arrangement on the trunk, and later on the neck and upper limbs. We report on a case of a 45-year-old female who presented with multiple oval to round hypopigmented papules measuring 5~15 mm on her trunk. Histopathologically, the lesions showed an increased amount of collagen fibers and decreased, fragmented elastic fibers in the dermis. The skin lesions were diagnosed as familial cutaneous collagenoma and no treatment was administered. To the best of our knowledge, our case is the first reported case of familial cutaneous collagenoma (FCC) in the Korean literature.

18.
Ann Dermatol ; 22(1): 61-2, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20548884

RESUMO

We present a case of accessory tragus (AT) which developed at an unusual site, the nasal vestibule, of a 1-day-old girl. To our knowledge, this is the first report of an accessory tragus that appears on the nasal vestibule.

19.
Biochem Biophys Res Commun ; 339(1): 392-8, 2006 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-16298337

RESUMO

SigH, an alternative sigma factor in Mycobacterium tuberculosis, is a central regulator in responses to the oxidative and heat stress. This SigH activity is specifically controlled by an anti-sigma factor RshA during expression of stress-related genes. Thus, the specific interaction (k(on)=1.15x10(5) (M(-1) s(-1)), k(off)=1.7x10(-3) (s(-1)), KD=15 nM, determined in this study) between SigH and RshA is crucial for the survival and pathogenesis of M. tuberculosis. Using phage-display peptide library, we defined three specific regions on RshA responsible for SigH binding. Three RshA mimetic peptides (DAHADHD, AEVWTLL, and CTPETRE) specifically inhibited the transcription initiated by SigH in vitro. One of them (DAHADHD) diminished the extent of binding of RshA to SigH in a dose-dependent manner. The binding affinity (KD) of this peptide to SigH was about 1.2 microM. These findings might provide some insights into the development of new peptide-based drugs for TB.


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Mycobacterium tuberculosis/metabolismo , Peptídeos/farmacologia , Fator sigma/metabolismo , Transcrição Gênica , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Peptídeos e Proteínas de Sinalização Intracelular/química , Dados de Sequência Molecular , Biblioteca de Peptídeos , Ligação Proteica , Fator sigma/genética , Ressonância de Plasmônio de Superfície
20.
Appl Environ Microbiol ; 70(8): 4522-31, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15294781

RESUMO

For the enzymatic production of chitosan oligosaccharides from chitosan, a chitosanase-producing bacterium, Bacillus sp. strain KCTC 0377BP, was isolated from soil. The bacterium constitutively produced chitosanase in a culture medium without chitosan as an inducer. The production of chitosanase was increased from 1.2 U/ml in a minimal chitosan medium to 100 U/ml by optimizing the culture conditions. The chitosanase was purified from a culture supernatant by using CM-Toyopearl column chromatography and a Superose 12HR column for fast-performance liquid chromatography and was characterized according to its enzyme properties. The molecular mass of the enzyme was estimated to be 45 kDa by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme demonstrated bifunctional chitosanase-glucanase activities, although it showed very low glucanase activity, with less than 3% of the chitosanase activity. Activity of the enzyme increased with an increase of the degrees of deacetylation (DDA) of the chitosan substrate. However, the enzyme still retained 72% of its relative activity toward the 39% DDA of chitosan, compared with the activity of the 94% DDA of chitosan. The enzyme produced chitosan oligosaccharides from chitosan, ranging mainly from chitotriose to chitooctaose. By controlling the reaction time and by monitoring the reaction products with gel filtration high-performance liquid chromatography, chitosan oligosaccharides with a desired oligosaccharide content and composition were obtained. In addition, the enzyme was efficiently used for the production of low-molecular-weight chitosan and highly acetylated chitosan oligosaccharides. A gene (csn45) encoding chitosanase was cloned, sequenced, and compared with other functionally related genes. The deduced amino acid sequence of csn45 was dissimilar to those of the classical chitosanase belonging to glycoside hydrolase family 46 but was similar to glucanases classified with glycoside hydrolase family 8.


Assuntos
Bacillus/enzimologia , Quitina/análogos & derivados , Quitina/metabolismo , Oligossacarídeos/metabolismo , Sequência de Aminoácidos , Bacillus/crescimento & desenvolvimento , Sequência de Bases , Quitosana , Clonagem Molecular , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/isolamento & purificação , Glicosídeo Hidrolases/metabolismo , Microbiologia Industrial/métodos , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade por Substrato
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