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101.
R Martin DS Buchan JS Baker J Young N Sculthorpe FM Grace 《Biology of sport / Institute of Sport》2015,32(4):307-313
The present study examined the physiological impact of a school based sprint interval training (SIT) intervention in replacement of standard physical education (SPE) class on cardio-respiratory fitness (CRF) and glucose homeostasis during the semester following summer vacation. Participants (n=49) were randomly allocated to either intervention (SIT; n=26, aged 16.9 ± 0.3 yrs) or control group who underwent standard physical education (SPE; n=23, aged 16.8 ± 0.6 yrs). CRF (VO2max) and glucose homeostasis were obtained prior-to and following 7 weeks of SIT exercise. Significant group x time interaction was observed for CRF (P < 0.01) with non-significant trends for fasting insulin (P= 0.08), and HOMA-IR (P=0.06). CRF decreased (P < 0.01) in SPE such that POST intervention CRF was significantly lower (P< 0.05) in SPE. Fasting plasma glucose (P < 0.01), insulin (P< 0.01) and HOMA-IR (P< 0.01) increased significantly amongst SPE. The main finding of the present study is that 7-weeks of SIT exercise is an effective method of maintaining (but not improving) CRF and fasting insulin homeostasis amongst school-going adolescents. SIT exercise demonstrates potential as a time efficient physiological adjunct to standard PE class in order to maintain CRF during the school term. 相似文献
102.
Background
The integrity of DNA molecules is fundamental for maintaining life. The DNA repair proteins protect organisms against genetic damage, by removal of DNA lesions or helping to tolerate them. DNA repair genes are best known from the gamma-proteobacterium Escherichia coli, which is the most understood bacterial model. However, genome sequencing raises questions regarding uniformity and ubiquity of these DNA repair genes and pathways, reinforcing the need for identifying genes and proteins, which may respond to DNA damage in other bacteria. 相似文献103.
Paul P Tak Maartje S Klapwijk Sophie FM Broersen Deliana A van de Geest Marieke Overbeek Gary S Firestein 《Arthritis research & therapy》2000,2(3):229-7
The kinetics of apoptosis and the apoptosis-regulating gene p53 in adjuvant arthritis (AA) were investigated to assess the value of the AA rat model for testing apoptosis-inducing therapies. Very few terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end-labeling (TUNEL)-positive cells were detected during the early phases of AA, but on day 23 (chronic arthritis) the percentage of TUNEL-positive cells was significantly increased. Expression of p53 in synovial tissue gradually increased from days 5-23, which was markedly higher than p53 levels in rheumatoid arthritis (RA) synovium. Significant apoptosis only occurs late in rat AA and is concordant with marked p53 overexpression, making it useful model for testing proapoptotic therapies, but rat AA is not the best model for p53 gene therapy because dramatic p53 overexpression occurs in the latter stages of the disease. 相似文献
104.
Chemical and kinetic evidence for an essential histidine in the phosphotriesterase from Pseudomonas diminuta 总被引:1,自引:0,他引:1
The pH rate profile for the hydrolysis of diethyl-p-nitrophenyl phosphate catalyzed by the phosphotriesterase from Pseudomonas diminuta shows a requirement for the deprotonation of an ionizable group for full catalytic activity. This functional group has an apparent pKa of 6.1 +/- 0.1 at 25 degrees C, delta Hion of 7.9 kcal/mol, and delta Sion of -1.4 cal/K.mol. The enzyme is not inactivated in the presence of the chemical modification reagents dithiobis-(2-nitrobenzoate), methyl methane thiosulfonate, carbodiimide, pyridoxal, butanedione, or iodoacetic acid and thus cysteine, asparate, glutamate, lysine, and arginine do not appear to be critical for catalytic activity. However, the phosphotriesterase is inactivated completely with methylene blue, Rose Bengal, or diethyl pyrocarbonate. The enzyme is not inactivated by diethyl pyrocarbonate in the presence of bound substrate analogs, and inactivation with diethyl pyrocarbonate is reversible upon addition of neutralized hydroxylamine. The modification of a single histidine residue by diethyl pyrocarbonate, as shown by spectrophotometric analysis, is responsible for the loss of catalytic activity. The pKinact for diethyl pyrocarbonate modification is 6.1 +/- 0.1 at 25 degrees C. These results have been interpreted to suggest that a histidine residue at the active site of phosphotriesterase is facilitating the reaction by general base catalysis. 相似文献
105.
Marie-Kathrin Breyer Robab Breyer-Kohansal Georg-Christian Funk Nicole Dornhofer Martijn A Spruit Emiel FM Wouters Otto C Burghuber Sylvia Hartl 《Respiratory research》2010,11(1):112
Background
In patients with COPD progressive dyspnoea leads to a sedentary lifestyle. To date, no studies exist investigating the effects of Nordic Walking in patients with COPD. Therefore, the aim was to determine the feasibility of Nordic Walking in COPD patients at different disease stages. Furthermore we aimed to determine the short- and long-term effects of Nordic Walking on COPD patients'' daily physical activity pattern as well as on patients exercise capacity.Methods
Sixty COPD patients were randomised to either Nordic Walking or to a control group. Patients of the Nordic Walking group (n = 30; age: 62 ± 9 years; FEV1: 48 ± 19% predicted) underwent a three-month outdoor Nordic Walking exercise program consisting of one hour walking at 75% of their initial maximum heart rate three times per week, whereas controls had no exercise intervention. Primary endpoint: daily physical activities (measured by a validated tri-axial accelerometer); secondary endpoint: functional exercise capacity (measured by the six-minute walking distance; 6MWD). Assessment time points in both groups: baseline, after three, six and nine months.Results
After three month training period, in the Nordic Walking group time spent walking and standing as well as intensity of walking increased (Δ walking time: +14.9 ± 1.9 min/day; Δ standing time: +129 ± 26 min/day; Δ movement intensity: +0.40 ± 0.14 m/s2) while time spent sitting decreased (Δ sitting time: -128 ± 15 min/day) compared to baseline (all: p < 0.01) as well as compared to controls (all: p < 0.01). Furthermore, 6MWD significantly increased compared to baseline (Δ 6MWD: +79 ± 28 meters) as well as compared to controls (both: p < 0.01). These significant improvements were sustained six and nine months after baseline. In contrast, controls showed unchanged daily physical activities and 6MWD compared to baseline for all time points.Conclusions
Nordic Walking is a feasible, simple and effective physical training modality in COPD. In addition, Nordic Walking has proven to positively impact the daily physical activity pattern of COPD patients under short- and long-term observation.Clinical trial registration
Nordic Walking improves daily physical activities in COPD: a randomised controlled trial - ISRCTN31525632 相似文献106.
Marcelo D Bechara Márcio C Moretzsohn Darío A Palmieri Jomar P Monteiro Maurício BacciJr Joaquim MartinsJr José FM Valls Catalina R Lopes Marcos A Gimenes 《BMC plant biology》2010,10(1):255
Background
The genus Arachis comprises 80 species and it is subdivided into nine taxonomic sections (Arachis, Caulorrhizae, Erectoides, Extranervosae, Heteranthae, Procumbentes, Rhizomatosae, Trierectoides, and Triseminatae). This genus is naturally confined to South America and most of its species are native to Brazil. In order to provide a better understanding of the evolution of the genus, we reconstructed the phylogeny of 45 species using the variation observed on nucleotide sequences in internal transcribed spacer regions (ITS1 and ITS2) and 5.8 S of nuclear ribosomal DNA. 相似文献107.
Ryosuke Kakinoki Ryosuke Ikeguchi Scott FM Dunkan Ken Nakayama Taiichi Matsumoto Soichi Ohta Takashi Nakamura 《Journal of brachial plexus and peripheral nerve injury》2010,5(1):1-9
The present study was designed to investigate the ameliorative potential of Ocimum sanctum and its saponin rich fraction in vincristine-induced peripheral neuropathic pain in rats. Peripheral neuropathy was induced in rats by administration of vincristine sulfate (50 μg/kg i.p.) for 10 consecutive days. The mechanical hyperalgesia, cold allodynia, paw heat hyperalgesia and cold tail hyperalgesia were assessed by performing the pinprick, acetone, hot plate and cold tail immersion tests, respectively. Biochemically, the tissue thio-barbituric acid reactive species (TBARS), super-oxide anion content (markers of oxidative stress) and total calcium levels were measured. Vincristine administration was associated with the development of mechanical hyperalgesia, cold allodynia, heat and cold hyperalgesia. Furthermore, vincristine administration was also associated with an increase in oxidative stress and calcium levels. However, administration of Ocimum sanctum (100 and 200 mg/kg p.o.) and its saponin rich fraction (100 and 200 mg/kg p.o.) for 14 days significantly attenuated vincristine-induced neuropathic pain along with decrease in oxidative stress and calcium levels. It may be concluded that Ocimum sanctum has ameliorative potential in attenuating chemotherapy induced-painful neuropathic state, which may be attributed to decrease in oxidative stress and calcium levels. Furthermore, saponin rich fraction of Ocimum sanctum may be responsible for its noted beneficial effect in neuropathic pain in rats. 相似文献
108.
Jonathan CM Clark Toru Akiyama Crispin R Dass Peter FM Choong 《Cancer cell international》2010,10(1):20
Background
Chondrosarcoma responds poorly to adjuvant therapy and new, clinically relevant animal models are required to test targeted therapy. 相似文献109.
Martí-Arbona R Xu C Steele S Weeks A Kuty GF Seibert CM Raushel FM 《Biochemistry》2006,45(7):1997-2005
The functional assignment of enzymes that catalyze unknown chemical transformations is a difficult problem. The protein Pa5106 from Pseudomonas aeruginosa has been identified as a member of the amidohydrolase superfamily by a comprehensive amino acid sequence comparison with structurally authenticated members of this superfamily. The function of Pa5106 has been annotated as a probablechlorohydrolase or cytosine deaminase. A close examination of the genomic content of P. aeruginosa reveals that the gene for this protein is in close proximity to genes included in the histidine degradation pathway. The first three steps for the degradation of histidine include the action of HutH, HutU, and HutI to convert L-histidine to N-formimino-L-glutamate. The degradation of N-formimino-L-glutamate to L-glutamate can occur by three different pathways. Three proteins in P. aeruginosa have been identified that catalyze two of the three possible pathways for the degradation of N-formimino-L-glutamate. The protein Pa5106 was shown to catalyze the deimination of N-formimino-L-glutamate to ammonia and N-formyl-L-glutamate, while Pa5091 catalyzed the hydrolysis of N-formyl-L-glutamate to formate and L-glutamate. The protein Pa3175 is dislocated from the hut operon and was shown to catalyze the hydrolysis of N-formimino-L-glutamate to formamide and L-glutamate. The reason for the coexistence of two alternative pathways for the degradation of N-formimino-L-glutamate in P. aeruginosa is unknown. 相似文献
110.
The bacterial phosphotriesterase (PTE) from Pseudomonas diminuta catalyzes the hydrolysis of organophosphate esters at rates close to the diffusion limit. X-ray diffraction studies have shown that a binuclear metal center is positioned in the active site of PTE and that this complex is responsible for the activation of the nucleophilic water from solvent. In this paper, the three-dimensional structure of PTE was determined in the presence of the hydrolysis product, diethyl phosphate (DEP), and a product analogue, cacodylate. In the structure of the PTE-diethyl phosphate complex, the DEP product is found symmetrically bridging the two divalent cations. The DEP displaces the hydroxide from solvent that normally bridges the two divalent cations in structures determined in the presence or absence of substrate analogues. One of the phosphoryl oxygen atoms in the PTE-DEP complex is 2.0 A from the alpha-metal ion, while the other oxygen is 2.2 A from the beta-metal ion. The two metal ions are separated by a distance of 4.0 A. A similar structure is observed in the presence of cacodylate. Analogous complexes have previously been observed for the product complexes of isoaspartyl dipeptidase, d-aminoacylase, and dihydroorotase from the amidohydrolase superfamily of enzymes. The experimentally determined structure of the PTE-diethyl phosphate product complex is inconsistent with a recent proposal based upon quantum mechanical/molecular mechanical simulations which postulated the formation of an asymmetrical product complex bound exclusively to the beta-metal ion with a metal-metal separation of 5.3 A. This structure is also inconsistent with a chemical mechanism for substrate hydrolysis that utilizes the bridging hydroxide as a base to abstract a proton from a water molecule loosely associated with the alpha-metal ion. Density functional theory (DFT) calculations support a reaction mechanism that utilizes the bridging hydroxide as the direct nucleophile in the hydrolysis of organophosphate esters by PTE. 相似文献