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1.
Antonie Van Leeuwenhoek ; 117(1): 99, 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38985203

ABSTRACT

A novel Gram-negative, white-pigmented, and auxin-producing strain, 20NA77.5T, was isolated from fresh water during cyanobacterial bloom period. Pairwise comparison of the 16S rRNA gene sequences showed that strain 20NA77.5T belonged to the genus Undibacterium and exhibited the highest sequence similarity to the type strains of Undibacterium danionis (98.00%), Undibacterium baiyunense (97.93%), Undibacterium macrobrachii (97.92%), and Undibacterium fentianense (97.71%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain 20NA77.5T and its related type strains were below 79.93 and 23.80%, respectively. The predominant fatty acids (> 10% of the total fatty acids) were C16:0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c). The genomic DNA G + C content of strain 20NA77.5T was found to be 48.61%. Based on the phylogenetic distinctness, chemotaxonomic features, and phenotypic features, strain 20NA77.5T is considered to represent a novel species of the genus Undibacterium, for which the name Undibacterium cyanobacteriorum sp. nov is proposed. The type strain is 20NA77.5T (= KCTC 8005T = LMG 33136T).


Subject(s)
Bacterial Typing Techniques , Base Composition , Cyanobacteria , DNA, Bacterial , Fatty Acids , Fresh Water , Indoleacetic Acids , Phylogeny , RNA, Ribosomal, 16S , RNA, Ribosomal, 16S/genetics , DNA, Bacterial/genetics , Fresh Water/microbiology , Indoleacetic Acids/metabolism , Fatty Acids/analysis , Cyanobacteria/genetics , Cyanobacteria/classification , Cyanobacteria/isolation & purification , Cyanobacteria/metabolism , Nucleic Acid Hybridization , Sequence Analysis, DNA , Water Microbiology
2.
Chemosphere ; 358: 142197, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38692365

ABSTRACT

Microalgae, including cyanobacteria and eukaryotic algae, are hotspots of primary production and play a critical role in global carbon cycling. However, these species often form blooms that poses a threat to aquatic ecosystems. Although the use of bacteria-derived cyanocides is regarded as an environmentally friendly method for controlling cyanobacterial blooms, only a few studies have examined their potential impact on ecosystems. This study is the first to explore the response of particle-attached (PA) and free-living (FL) bacteria to the dynamics of microalgal communities induced by the biological cyanocide paucibactin A. The microalgal community dynamics were divided into two distinct phases [phase I (days 0-2) and phase II (days 3-7)]. In phase I, paucibactin A caused a sudden decrease in the cyanobacterial concentration. Phase II was characterized by increased growth of eukaryotic microalgae (Scenedesmus, Pediastrum, Selenastrum, and Coelastrum). The stability of the bacterial community and the contribution of stochastic processes to community assembly were more pronounced in phase II than in phase I. The microalgal dynamics triggered by paucibactin A coincided with the succession of the PA and FL bacterial communities. The lysis of cyanobacteria in phase I favored the growth of microbial organic matter degraders in both the PA (e.g., Aeromonas and Rheinheimera) and FL (e.g., Vogesella) bacterial communities. In phase II, Lacibacter, Phycisphaeraceae, and Hydrogenophaga in the PA bacterial community and Lacibacter, Peredibacter, and Prosthecobacter in the FL bacterial community showed increased relative abundances. Overall, the FL bacterial community exhibited greater sensitivity to the two sequential processes compared with the PA bacterial community. These results highlight the need for studies evaluating the impact of biological cyanocides on aquatic ecosystems when used to control natural cyanobacterial blooms.


Subject(s)
Cyanobacteria , Microalgae , Microalgae/metabolism , Cyanobacteria/metabolism , Cyanobacteria/growth & development , Ecosystem , Bacteria/metabolism , Eutrophication , Microbiota
3.
Sci Total Environ ; 928: 172482, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38621529

ABSTRACT

Various environmental factors play a role in the formation and collapse of Microcystis blooms. This study investigates the impact of heavy rainfall on cyanobacterial abundance, microbial community composition, and functional dynamics in the Nakdong River, South Korea, during typical and exceptionally rainy years. The results reveal distinct responses to rainfall variations, particularly in cyanobacterial dominance and physicochemical characteristics. In 2020, characterized by unprecedented rainfall from mid-July to August, Microcystis blooms were interrupted significantly, exhibiting lower cell densities and decreased water temperature, compared to normal bloom patterns in 2019. Moreover, microbial community composition varied, with increases in Gammaproteobacteria and notably in genera of Limnohabitans and Fluviicola. These alterations in environmental conditions and bacterial community were similar to those of the post-bloom period in late September 2019. It shows that heavy rainfall during summer leads to changes in environmental factors, consequently causing shifts in bacterial communities akin to those observed during the autumn-specific post-bloom period in typical years. These changes also accompany shifts in bacterial functions, primarily involved in the degradation of organic matter such as amino acids, fatty acids, and terpenoids, which are assumed to have been released due to the significant collapse of cyanobacteria. Our results demonstrate that heavy rainfall in early summer induces changes in the environmental factors and subsequently microbial communities and their functions, similar to those of the post-bloom period in autumn, leading to the earlier breakdown of Microcystis blooms.


Subject(s)
Microbiota , Microcystis , Rain , Rivers , Microcystis/growth & development , Republic of Korea , Rivers/microbiology , Eutrophication , Environmental Monitoring , Seasons
4.
Article in English | MEDLINE | ID: mdl-38500018

ABSTRACT

BACKGROUND: The global burden of type 2 diabetes (T2D) is growing, and the age of onset is widening, resulting in increasing numbers of young adults and elderly patients with T2D. Age-specific diabetes care needs have yet to be fully explored. AIMS: This study examined (1) differences in patient-reported and clinical characteristics by age group and (2) the effect of age on two proxy measures assessing psychological health and self-care adherence after adjusting for potential mediators. METHODS: A cross-sectional, correlational design was used. Adults with type 2 diabetes (T2D) were recruited from a university hospital in Korea between 2019 and 2020. Participants were divided into four groups based on years of age (40s and younger group [n = 27]; 50s group [n = 47]; 60s group [n = 54]; and 70s and older group [n = 48]) to compare patient-reported and clinical characteristics. Chi-square tests, ANOVA, Kruskal-Wallis tests, and logistic regression analysis were performed to assess group differences and effect of age on psychological health and self-care adherence. RESULTS: Of 178 participants, two-thirds were men (n = 114; 64.41%). The mean ages in the 40s and younger, 50s, 60s, and 70s and older groups were 39.4, 54.7, 63.9, and 76.0 years, respectively. There were significant differences in patient-reported and clinical characteristics by age group. The youngest group reported the poorest psychological health and self-care behaviors. Although the oldest group showed the poorest physical functioning, this group also showed the highest self-care adherence and the best psychological health. Regarding clinical characteristics, traditional diabetes-related blood test results showed no significant group differences. LINKING EVIDENCE TO ACTION: Age-specific diabetes care needs were identified in adults with T2D. Interventions to improve psychological health and priming effects of behavioral adherence need to be developed. Furthermore, meticulous investigation to detect potential complications early is essential in adults with T2D.

5.
Int J Biol Macromol ; 259(Pt 1): 129130, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38181917

ABSTRACT

In this study, the recovery of Atrina pectinata posterior adductor polysaccharides (APP-PS) using subcritical water extraction (SWE) was optimized by response surface methodology (RSM) and the physicochemical and biological properties of the recovered APP-PS were evaluated. The optimal extraction conditions, which resulted in a maximum yield of 55.58 ± 1.12 %, were temperature, 152.08 °C; extraction time, 10 min; solid-liquid ratio, 30 g/600 mL. The obtained APP-PS was found to be 88.05 ± 0.17 % total sugar. Fourier transform infrared (FT-IR) and Nuclear magnetic resonance (NMR) analyses confirmed the presence of the α-coordination of D-glucan in the polymer sample. The analysis of monosaccharide composition, along with thermogravimetric analysis, revealed the typical structure of the sample, composed of glucose alone. Total phenolic contents of APP-PS were measured as 5.47 ± 0.01 mg Gallic acid/g of dry sample and total flavonoids contents were determined to be 0.78 ± 0.06 mg Quercetin/g of dry sample. For biological activities, ABTS+, DPPH and FRAP antioxidant activities were measured to be 20.00 ± 0.71, 2.35 ± 0.05 and 4.02 ± 0.07 µg Trolox equivalent/100 g of dry sample, respectively. Additionally ACE inhibitory was confirmed to be 87.02 ± 0.47 %. These results showed that SWE is an effective method to recover biofunctional materials from marine organisms.


Subject(s)
Biological Products , Water , Water/chemistry , Spectroscopy, Fourier Transform Infrared , Plant Extracts/chemistry , Antioxidants/pharmacology , Antioxidants/chemistry , Polysaccharides/pharmacology , Polysaccharides/chemistry
6.
Sci Diabetes Self Manag Care ; 49(5): 351-361, 2023 10.
Article in English | MEDLINE | ID: mdl-37658651

ABSTRACT

PURPOSE: The purpose of the study was to examine the associations between perceived hypoglycemia and psycho-behavioral and clinical factors in persons with type 2 diabetes (T2D). METHODS: Adults with T2D were recruited from outpatient clinics in a university hospital in Korea. Sociodemographics, psycho-behavioral and clinical factors, and body composition were assessed. The participants were divided into 2 groups reporting perceived hypoglycemia or not in the previous month based on an item of the Control Problem Scale. Group differences were compared at α = .05 using SPSS (version 26.0). RESULTS: Of 177 participants, approximately one-third (n = 67) perceived hypoglycemia. The hypoglycemia group reported poor health-related quality of life, frequent blood monitoring and foot care, and sleep difficulties. However, no differences between groups were identified for diet, exercise, or glycosylated hemoglobin. The hypoglycemia group had a lower body mass index and a trend toward a lower skeletal muscle mass and fat free mass. CONCLUSIONS: Perceived hypoglycemia was associated with psycho-behavioral factors and body composition. Importantly, some persons on oral antidiabetic medications that do not cause hypoglycemia still perceived hypoglycemia. Further investigation is warranted to examine the efficacy of strategies to minimize hypoglycemia and inappropriate fear of hypoglycemia. In addition, clinicians should be aware of the potential risk of hypoglycemia in persons with lower muscle mass.


Subject(s)
Diabetes Mellitus, Type 2 , Hypoglycemia , Humans , Adult , Diabetes Mellitus, Type 2/drug therapy , Quality of Life , Hypoglycemic Agents , Body Composition
7.
J Obes Metab Syndr ; 32(3): 259-268, 2023 Sep 30.
Article in English | MEDLINE | ID: mdl-37752708

ABSTRACT

Background: This study investigates differences in telomere length according to obesity, cardiovascular disease (CVD) risk factors, and fitness level in South Korean males. Methods: The subjects of this study were males in their 10s to 50s (n=249). We measured obesity indices, CVD risk factors, leukocyte telomere length (LTL), and cardiorespiratory fitness (CRF). Correlation and regression analyses were performed to analyze the data. Results: Measurement of participants' obesity indices, CVD risk factors, and maximum oxygen intake and analyzing their correlations with LTL revealed that LTL and CRF decreased with age and the levels and numbers of obesity indices and CVD risk factors increased. The LTL showed differences according to whether subjects exhibited obesity or dyslipidemia and by CRF level. When all the variables that influence the LTL were adjusted, the LTL became shorter as the age and low-density lipoprotein cholesterol (LDL-C) level increased, and it became longer as the maximum rate of oxygen utilization (VO2max) increased. When the age and CVD risk factors that influence the LTL were adjusted according to obesity and CRF for the obese group, the LTL became shorter as the age and LDL-C level increased (P<0.01), and it became longer as VO2max increased (P<0.01). Conclusion: We found that obesity influenced the LTL by increasing the levels of CVD risk factors and decreasing CRF, whereas maintaining high CRF could alleviate the effects of obesity and CVD risk factors according to age while maintaining and influencing the elongation of LTL.

8.
Antonie Van Leeuwenhoek ; 116(12): 1317-1326, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37773469

ABSTRACT

A novel species of the genus Emticicia, designated BHSR1T, was isolated from a water sample that was collected from the Nakdong River, Republic of Korea, and its taxonomic affiliation was studied using a polyphasic approach. This bacterium was Gram-stain-negative, non-motile, aerobic, curved, rod-shaped, and oxidase- and catalase-negative. The bacterium grew optimally at 37 °C, pH 7.5 and 0% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain BHSR1T should be affiliated with the genus Emticicia, with a high similarity to Emticicia fontis KCTC 52248T (98.10%). Phylogenomic analysis also suggested that the strain represents a novel species in the genus Emticicia. The genomic G + C content was 41.9%. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization between strain BHSR1T and its closely related relatives in the genus Emticicia were in ranges of 71.1-75.8%, 69.4-77.5% and 18.6-19.9%, respectively. The gene cluster within BHSR1T contained genes encoding enzymes that could be involved in hormone degradation. The major cellular fatty acids (> 10%) were summed feature 3 (comprising C16:1ω6c and/or C16:1ω7c) and iso-C15:0. With regards to the polar lipid profile, phosphatidylethanolamine (PE), two unidentified aminolipids and three unidentified lipids were identified as the major compounds. The major respiratory quinone was menaquinone (MK)-7. Based on its phylogenetic, phenotypic, chemotaxonomic, and genomic features, strain BHSR1T should be considered a novel species in the genus Emticicia of the family Spirosomaceae, for which the name Emticicia fluvialis sp. nov. is proposed. The type strain was considered BHSR1T (= KCTC 92622T = GDMCC 1.3740T).


Subject(s)
Fatty Acids , Rivers , Rivers/microbiology , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Bacterial Typing Techniques , DNA, Bacterial/genetics , Fatty Acids/chemistry , Republic of Korea
9.
Mar Drugs ; 21(6)2023 May 26.
Article in English | MEDLINE | ID: mdl-37367653

ABSTRACT

In this study, we characterized the bioactive properties of three important brown seaweed species, Sargassum thunbergii, Undaria pinnatifida, and Saccharina japonica, by subcritical water extraction (SWE), as these species are well known for their beneficial health effects. Their physiochemical properties, including potential antioxidant, antihypertensive, and α-glucosidase inhibitory activity, and the antibacterial activity of the hydroysates were also analyzed. The highest total phlorotannin, total sugar content, and reducing sugar content in the S. thunbergii hydrolysates were 38.82 ± 0.17 mg PGE/g, 116.66 ± 0.19 mg glucose/g dry sample, and 53.27 ± 1.57 mg glucose/g dry sample, respectively. The highest ABTS+ and DPPH antioxidant activities were obtained in the S. japonica hydrolysates (124.77 ± 2.47 and 46.35 ± 0.01 mg Trolox equivalent/g, respectively) and the highest FRAP activity was obtained in the S. thunbergii hydrolysates (34.47 ± 0.49 mg Trolox equivalent/g seaweed). In addition, the seaweed extracts showed antihypertensive (≤59.77 ± 0.14%) and α-glucosidase inhibitory activity (≤68.05 ± 1.15%), as well as activity against foodborne pathogens. The present findings provide evidence of the biological activity of brown seaweed extracts for potential application in the food, pharmaceutical, and cosmetic sectors.


Subject(s)
Seaweed , Water , Water/chemistry , alpha-Glucosidases , Antioxidants/chemistry , Antihypertensive Agents/analysis , Seaweed/chemistry , Glucose , Plant Extracts/pharmacology
10.
Cancers (Basel) ; 14(23)2022 Nov 27.
Article in English | MEDLINE | ID: mdl-36497331

ABSTRACT

G protein-coupled receptors (GPCRs) are a diverse family of cell surface receptors implicated in various physiological functions, making them common targets for approved drugs. Many GPCRs are abnormally activated in cancers and have emerged as therapeutic targets for cancer. Neuropeptide FF receptor 2 (NPFFR2) is a GPCR that helps regulate pain and modulates the opioid system; however, its function remains unknown in cancers. Here, we found that NPFFR2 is significantly up-regulated in liver cancer and its expression is related to poor prognosis. Silencing of NPFFR2 reduced the malignancy of liver cancer cells by decreasing cell survival, invasion, and migration, while its overexpression increased invasion, migration, and anchorage-independent cell growth. Moreover, we found that the malignant function of NPFFR2 depends on RhoA and YAP signaling. Inhibition of Rho kinase activity completely restored the phenotypes induced by NPFFR2, and RhoA/F-Actin/YAP signaling was controlled by NPFFR2. These findings demonstrate that NPFFR2 may be a potential target for the treatment of hepatocellular carcinoma.

11.
J Bone Metab ; 29(2): 103-111, 2022 May.
Article in English | MEDLINE | ID: mdl-35718927

ABSTRACT

BACKGROUND: Aging leads to significant bone loss and elevated osteoporosis risk. Exercise slows age-related bone loss; however, the effects of various moderate-intensity exercise training volumes on bone metabolism remain unclear. This study aimed to determine the degree to which different volumes of moderate-intensity aerobic exercise training influence bone mineral density (BMD), bone mineral content (BMC), femoral trabecular bone microarchitecture, and cortical bone in middle-aged mice. METHODS: Twenty middle-aged male C57BL/6 mice were randomly assigned 8 weeks of either (1) non-exercise (CON); (2) moderate-intensity with high-volume exercise (EX_MHV); or (3) moderate-intensity with low-volume exercise (EX_MLV) (N=6-7, respectively). Femoral BMD and BMC were evaluated using dual energy X-ray absorptiometry, and trabecular and cortical bone were measured using micro-computed tomography. RESULTS: Femoral BMD in EX_MHV but not EX_MLV was significantly higher (P<0.05) than in CON. The distal femoral fractional trabecular bone volume/tissue volume (BV/TV, %) was significantly higher (P<0.05) in both EX_MHV and EX_MLV than in CON mice. Increased BV/TV was induced by significantly increased trabecular thickness (mm) and tended to be higher (P<0.10) in BV (mm3) and lower in trabecular separation (mm) in EX_MHV and EX_MLV than in CON. The femoral mid-diaphysis cortical bone was stronger in EX_MLV than EX_MHV. CONCLUSIONS: Long-term moderate-intensity aerobic exercise with low to high volumes can be thought to have a positive effect on hindlimb BMD and attenuate age-associated trabecular bone loss in the femur. Moderate-intensity aerobic exercise may be an effective and applicable exercise regimen to prevent age-related loss of BMD and BV.

12.
J Microbiol ; 60(6): 602-609, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35489018

ABSTRACT

Protein phosphatase (PPase) inhibition assay (PPIA) is widely used to analyze the concentration of microcystins (MCs) because it is comparatively less expensive and faster than other assays. This study aimed to optimize the PPIA by determining a suitable reaction terminator and an optimal methanol concentration in the sample. The most suitable reaction time was 90 min, with the corresponding methanol concentration in the sample being 15% or less. When p-nitrophenyl phosphate (pNPP) was used as a substrate, copper chloride solution was suitably used as a reaction terminator, and when 4-methylumbelliferyl phosphate (MUP) was used, a glycine buffer not only increased the measurement sensitivity of the reaction product but also terminated the enzymatic reaction. When PPase 1 and MUP were used as an enzyme and a substrate, respectively, the limit of quantitation for MC-leucine/arginine (LR) was 0.02 µg/L, whereas it was 0.1 µg/L when pNPP was used as a substrate. The proposed method facilitated the measurement of MC-LR concentration without additional pretreatments, such as concentration or purification; therefore, this method was suitable and feasible for the continuous monitoring of MCs in drinking water.


Subject(s)
Drinking Water , Microcystins , Methanol , Phosphoprotein Phosphatases
13.
Toxins (Basel) ; 14(2)2022 02 08.
Article in English | MEDLINE | ID: mdl-35202155

ABSTRACT

Blooms of harmful cyanobacteria Microcystis aeruginosa lead to an adverse effect on freshwater ecosystems, and thus extensive studies on the control of this cyanobacteria's blooms have been conducted. Throughout this study, we have found that the two bacteria Aeromonas bestiarum HYD0802-MK36 and Pseudomonas syringae KACC10292T are capable of killing M. aeruginosa. Interestingly, these two bacteria showed different algicidal modes. Based on an algicidal range test using 15 algal species (target and non-target species), HYD0802-MK36 specifically attacked only target cyanobacteria M. aeruginosa, whereas the algicidal activity of KACC10292T appeared in a relatively broad algicidal range. HYD0802-MK36, as a direct attacker, killed M. aeruginosa cells when direct cell (bacterium)-to-cell (cyanobacteria) contact happens. KACC10292T, as an indirect attacker, released algicidal substance which is located in cytoplasm. Interestingly, algicidal activity of KACC10292T was enhanced according to co-cultivation with the host cyanobacteria, suggesting that quantity of algicidal substance released from this bacterium might be increased via interaction with the host cyanobacteria.


Subject(s)
Aeromonas/chemistry , Bacterial Toxins/toxicity , Harmful Algal Bloom/drug effects , Herbicides/toxicity , Microcystis/drug effects , Pseudomonas syringae/chemistry
15.
J Obes Metab Syndr ; 30(2): 81-92, 2021 Jun 30.
Article in English | MEDLINE | ID: mdl-34045368

ABSTRACT

Obesity is a prevalent and complex disease. The prevalence of obesity in Korea increased from 29.7% in 2010 to 35.7% in 2018, with the prevalence of abdominal obesity being 23.8% in 2018. Obesity contributes to medical costs and socioeconomic burden due to associated comorbidities. The treatment and management of obesity is changing based on new clinical evidence. The 2020 Korean Society for the Study of Obesity Guideline for the Management of Obesity in Korea summarizes evidence-based recommendations and treatment guidelines.

16.
Front Physiol ; 12: 800301, 2021.
Article in English | MEDLINE | ID: mdl-35273515

ABSTRACT

Advancing age is associated with bone loss and an increased risk of osteoporosis. Exercise training improves bone metabolism and peripheral nerve regeneration, and may play a critical role in osteogenesis and increase in skeletal nerve fiber density. In this study, the potential positive role of aerobic exercise training in bone metabolism and skeletal nerve regeneration was comprehensively evaluated in 14-month-old male C57BL/6 mice. The mice were divided into two groups: no exercise (non-exercise group) and 8-weeks of aerobic exercise training (exercise group), with six mice in each group. Dual-energy X-ray absorptiometry and micro-computed tomography showed that femoral and tibial bone parameters improved after aerobic exercise training. Greater skeletal nerve fiber density was also observed in the distal femoral and proximal tibial periostea, measured and analyzed by immunofluorescence staining and confocal microscopy. Pearson correlation analysis revealed a significant association between skeletal nerve densities and trabecular bone volume/total volume ratios (distal femur; R 2 = 0.82, p < 0.05, proximal tibia; R 2 = 0.59, p = 0.07) in the exercise group; while in the non-exercise group no significant correlation was found (distal femur; R 2 = 0.10, p = 0.54, proximal tibia; R 2 = 0.12, p = 0.51). Analysis of archival microarray database confirmed that aerobic exercise training changed the microRNA profiles in the mice femora. The differentially expressed microRNAs reinforce the role of aerobic exercise training in the osteogenic and neurogenic potential of femora and tibiae. In conclusion, 8-weeks of aerobic exercise training positively regulate bone metabolism, an effect that paralleled a significant increase in skeletal nerve fiber density. These findings suggest that aerobic exercise training may have dual utility, both as a direct stimulator of bone remodeling and a positive regulator of skeletal nerve regeneration.

17.
Nutrients ; 12(11)2020 Oct 26.
Article in English | MEDLINE | ID: mdl-33114585

ABSTRACT

We have recently demonstrated in young adults that an anabolic response with mixed meal protein intake above ~35 g/meal, previously recognized as an "optimal" protein dose, was further stimulated. However, it is unknown if this applies to older adults. We therefore examined anabolic response to a mixed meal containing either 35 g (MOD, moderate amount of protein) or 70 g (HIGH, high amount of protein) in a randomized cross-over metabolic study in older adults (n = 8). Primed continuous infusions of L-[2H5] phenylalanine and L-[2H2]tyrosine were performed to determine whole-body protein kinetics and muscle protein fractional synthesis rate (MPS) in basal fasted and fed states. Whole-body protein kinetics (NB, net protein balance; PS, protein synthesis; PB, protein breakdown) and MPS was expressed as changes from the baseline post-absorptive state. Consistent with our previous findings in young adults, both feedings resulted in a positive NB, with HIGH being more positive than MOD. Furthermore, NB (expressed as g protein∙240 min) increased linearly with an increasing amount of protein intake, expressed relative to lean body mass. The positive NB was achieved due mainly to the suppression of PB in both MOD and to a greater extent HIGH, while PS was only increased in HIGH. Consistent with the whole-body data, MPS was significantly higher in HIGH than MOD. Plasma concentrations of essential amino acids and insulin were greater in HIGH vs. MOD. We conclude that in the context of mixed meals, whole-body anabolic response linearly increases with increasing protein intake primarily through the suppression of PB, and MPS was further stimulated with protein intake above the previously considered "optimal" protein dose in older adults.


Subject(s)
Dietary Proteins/metabolism , Eating/physiology , Meals/physiology , Postprandial Period/physiology , Protein Biosynthesis/physiology , Absorptiometry, Photon , Aged , Basal Metabolism/physiology , Body Composition/physiology , Cross-Over Studies , Fasting/physiology , Female , Healthy Volunteers , Humans , Kinetics , Male
18.
Environ Sci Technol ; 54(12): 7185-7193, 2020 06 16.
Article in English | MEDLINE | ID: mdl-32496782

ABSTRACT

Despite the implementation of intensive phosphorus reduction measures, periodic outbreaks of cyanobacterial blooms in large rivers remain a problem in Korea, raising the need for more effective solutions to reduce their occurrence. This study sought to evaluate whether phosphorus or nitrogen limitation is an effective approach to control cyanobacterial (Microcystis) blooms in river conditions that favor this non-nitrogen-fixing genus. These conditions include nutrient enrichment, high water temperature, and thermal stratification during summer. Mesocosm bioassays were conducted to investigate the limiting factors for cyanobacterial blooms in a river reach where severe Microcystis blooms occur annually. We evaluated the effect of five different nitrogen (3, 6, 9, 12, and 15 mg/L) and phosphorus (0.01, 0.02, 0.05, 0.1, and 0.2 mg/L) concentrations on algae growth. The results indicate that nitrogen treatments stimulated cyanobacteria (mostly Microcystis aeruginosa) more than phosphorus. Interestingly, phosphorus additions did not stimulate cyanobacteria, although it did stimulate Chlorophyceae and Bacillariophyceae. We conclude that phosphorus reduction might have suppressed the growth of Chlorophyceae and Bacillariophyceae more than that of cyanobacteria; therefore, nitrogen or at least both nitrogen and phosphorus control appears more effective than phosphorus reductions alone for reducing cyanobacteria in river conditions that are favorable for non-nitrogen-fixing genera.


Subject(s)
Microcystis , Eutrophication , Lakes , Nitrogen/analysis , Phosphorus/analysis , Republic of Korea , Rivers
19.
J Obes Metab Syndr ; 29(1): 18-25, 2020 Mar 30.
Article in English | MEDLINE | ID: mdl-32146733

ABSTRACT

Global average data suggest that the prevalence of obese and overweight males is much higher than that of females in some regions. The gender gap in obese and overweight individuals has deepened in many countries, and the gap is more prominent in overweight than in obesity. In particular, the prevalence of male obesity has continuously increased in the Republic of Korea over the past two decades, whereas the increase in female obesity has slowed and may even have plateaued. The cutoff point for obesity in Korea is a body mass index of ≥25 kg/m2, which is equivalent to the international classification of being overweight. Researching obesity in males is not as prevalent as studying obesity in females. Previous studies have rarely considered obesity type (android vs. gynoid), hormones (testosterone, androgen, etc.), awareness of body shape, or special resources such as exercise interventions to improve male weight issues. Adaptations to exercise interventions show individual variability as well as differences between men and women. Therefore, integrated approaches to research should be adopted, including evaluation of socio-demographic and physiological characteristics, to ensure that such interventions are not simply a symptomatic treatment but are actually treating the root cause of the obesity.

20.
J Exerc Rehabil ; 15(5): 663-666, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31723554

ABSTRACT

The purpose of this study was to compare performance-related physical fitness factors and anaerobic power between national and backup players to enhance the performance of wheelchair badminton players and to discover and foster new athletes. This study included 12 wheel-chair badminton players divided into two groups: national players (n=7) and backup players (n=5). Collected data included cardiorespiratory endurance, muscle endurance, muscle strength, power, agility, and anaerobic power. Results indicated that the national players achieved a significantly higher level of muscle endurance, peak power, and mean power than the backup players. Although none of the parameters showed statistically significant differences, the performance levels of the national players were higher than those of the backup players. Because the physical fitness aspects of wheelchair players vary according to their ability and are essential factors, individualized training programs for enhancing performance and preventing injuries among wheelchair badminton players should be developed.

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