Morphological and photosynthetic responses of Quercus crispula seedlings to high-light conditions     

Matsuki S  Ogawa K  Tanaka A  Hara T 《Tree physiology》2003,23(11):769-775

We investigated morphological and photosynthetic responses of current-year seedlings of oak (Quercus crispula Blume) under high-light conditions. Quercus crispula seedlings were grown from seed in a relative photosynthetically active photon flux density (RPPFD) of 100, 10 or 2%. There was no difference in total dry mass between 100 and 10% RPPFD. At the end of the growing season, plants grown in 2% RPPFD had a lower total dry mass than those grown in 100 or 10% RPPFD. Seedlings grown in 100% RPPFD showed morphological acclimation, i.e., high root/shoot ratios and high leaf mass per area. De-epoxidation level in the xanthophyll cycle and activity of an antioxidant enzyme were highest in 100% RPPFD, but total chlorophyll concentration and photosynthetic rate were highest in 10% RPPFD. These results indicate that excess photons were generated in 100% RPPFD, leading to increased capacities for dissipation of received light energy through the xanthophyll cycle and for scavenging of reactive oxygen species through the water-water cycle. Nevertheless, a midday decrease in dark-adapted quantum yield of photosystem II (F(v)/F(m)) indicated that seedlings grown in 100% RPPFD were suffering from photoinhibition. We conclude that Q. crispula current-year seedlings have high morphological acclimation to high light but that photosynthetic efficiency cannot be maintained under high-light conditions even with a photoprotection system.  相似文献   

Retention-tree groups in clear-cuts: Do they constitute ‘life-boats’ for spiders and carabids?     

Katja Matveinen-Huju  Jari Niemel  Hannu Rita  Robert B. O&#x;Hara 《Forest Ecology and Management》2006,230(1-3):119-135

Green-tree retention aims at maintaining biodiversity while harvesting timber, but knowledge of its efficiency is still limited. Green-tree retention may function as a ‘life-boat’ for organisms, maintain structural features, or create stepping-stones in the harvested landscape. The aim of this study is to determine whether larger retention-tree groups established in clear-cuts maintain forest species better than smaller ones. We posed hypotheses for different habitat affinity groups of spiders and carabids, and tested them in Eastern Finland with 11 retention-tree groups, 0.09–0.55 ha in size (47–385 trees per tree group). Although some of the analysed species responded as expected, we did not find unambiguous support for the hypotheses that (1) species requiring forest and/or (medium-) moist habitat should be more abundant in larger retention-tree groups, (2) species requiring (semi-) open and/or (medium-) dry habitat should be more common in smaller retention-tree groups, and (3) species indifferent with respect to light intensity and moisture should be caught in equal numbers in all retention-tree groups irrespective of their size. However, the mean numbers of individuals of many forest species and/or species requiring (medium-) moist habitat decreased over the 3 years after logging in all retention-tree groups, whereas the mean numbers of many species of (semi-) open and/or (medium-) dry habitat increased over the 3 years after logging. Furthermore, species composition changed from the pre-treatment year for spiders. We conclude that green-tree retention is justified because (1) retention-tree groups tend to maintain some forest species, thereby mitigating the effects of clear-cutting, at least in the short term, (2) they provide dead wood, large old trees, and other structural features, and (3) there are gaps in our ecological knowledge that warrant the adoption of the precautionary principle. However, as there are economic costs associated with the establishment of retention-tree groups, their ecological benefits as compared to other approaches aimed at maintaining biodiversity should be assessed carefully.  相似文献   

New method to evaluate water-soluble antioxidant activity based on protein structural change   总被引：1，自引：0，他引：1  

Terashima M  Nakatani I  Harima A  Nakamura S  Shiiba M 《Journal of agricultural and food chemistry》2007,55(1):165-169

A simple method to evaluate antioxidant activities of water-soluble ingredients of foods has been developed. Protective effects of antioxidants against hypochlorite radical or hydroxyl radical have been studied by comparing changes in absorbance of myoglobin (a standard reference) at 409 nm. Protective ratio, defined by absorbance changes of myoglobin with or without the antioxidant, was a good indicator to quantitatively evaluate the antioxidant activity against the hypochlorite radical or the hydroxyl radical, respectively. Radar charts indicating the antioxidant activities against DPPH (1,1-diphenyl-2-picrylhydrazyl), hypochlorite radical, and hydroxyl radical clearly differentiated the characteristics of five antioxidants including carnosine, glutathione, and vitamin C. By comparison of the radar charts, antioxidant activity of bonito meat hydrolysate was found to have similar characteristics to that of carnosine. The simple method proposed in this study would be useful for evaluating and characterizing the activities of water-soluble antioxidants contained in various food materials.  相似文献   

Peptides derived from dolicholin, a phaseolin-like protein in country beans (Dolichos lablab), potently stimulate cholecystokinin secretion from enteroendocrine STC-1 cells     

Sufian MK  Hira T  Asano K  Hara H 《Journal of agricultural and food chemistry》2007,55(22):8980-8986

Peptides derived from soybean beta-conglycinin and pork protein stimulate cholecystokinin (CCK) secretion from the enteroendocrine cells (EECs) and suppress food intake. Here we examined CCK-releasing activities from the enteroendocrine cell line STC-1, in peptides derived from underutilized legumes, and found much higher activity in the peptic hydrolysate of Country beans (CBP) compared to that from other legume-derived peptides including beta-conglycinin peptone. Active components in CBP were separated into acetonitrile-soluble fractions, but the activities were abolished after pronase treatment. To identify the Country bean protein containing the active peptides, Country bean protein extracts in an alkaline solution (CBE) were fractionated based on isoelectric point or molecular weight. Peptones prepared from CBE fractions containing a 51 kDa major protein stimulated CCK release, but other fractions did not. N-Terminal sequence analysis indicated that the 51 kDa protein is a phaseolin-like globular protein, and we designated this protein dolicholin. These results indicate that Country bean-derived peptides are very potent legume peptides in stimulating CCK secretion from EECs and that the stimulant peptides originate from dolicholin, a newly identified phaseolin-like globular protein in Country beans.  相似文献   

Seroepidemiologic survey of Coxiella burnetii and attempt to detect Coxiella DNA in aged non-laying chickens in a prefecture of Japan where poultry farming prospers     

Muramatsu Y  Hukuta K  Satoh S  Muramatsu M  Nishimura M  Nagahata H  Ueno H  Morita C  Tamura Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(9):1007-1008

The indirect fluorescent antibody test (IFAT) revealed seropositivity to Coxiella burnetii in aged non-laying chickens in poultry farms in a prefecture in the central part of Japan. Seropositivity was 7%, and antibody titers ranged from 16 to 64. No DNA fragment specific for C. burnetii was detected in the chickens by nested-PCR. The prevalence of C. burnetii infection in a prefecture of Japan in which poultry farming prospers was 7%.  相似文献   

A critical role for the innate immune signaling molecule IRAK-4 in T cell activation     

Suzuki N  Suzuki S  Millar DG  Unno M  Hara H  Calzascia T  Yamasaki S  Yokosuka T  Chen NJ  Elford AR  Suzuki J  Takeuchi A  Mirtsos C  Bouchard D  Ohashi PS  Yeh WC  Saito T 《Science (New York, N.Y.)》2006,311(5769):1927-1932

IRAK-4 is a protein kinase that is pivotal in mediating signals for innate immune responses. Here, we report that IRAK-4 signaling is also essential for eliciting adaptive immune responses. Thus, in the absence of IRAK-4, in vivo T cell responses were significantly impaired. Upon T cell receptor stimulation, IRAK-4 is recruited to T cell lipid rafts, where it induces downstream signals, including protein kinase C activation through the association with Zap70. This signaling pathway was found to be required for optimal activation of nuclear factor kappaB. Our findings suggest that T cells use this critical regulator of innate immunity for the development of acquired immunity, suggesting that IRAK-4 may be involved in direct signal cross talk between the two systems.  相似文献   

Protective Effect of Stachybotrys microspora Triprenyl Phenol-7on the Deposition of IgA to the Glomerular Mesangium in Nivalenol-induced IgA Nephropathy Using BALB/c Mice     

S Kemmochi  H Hayashi  E Taniai  K Hasumi  Y Sugita-Konishi  S Kumagai  K Mitsumori  M Shibutani 《Journal of toxicologic pathology》2012,25(2):149-154

Activators of tissue proteolysis including Stachybotrys microspora triprenyl phenol (SMTP)-7 are a new class of agents that are expected to be effective for amelioration of chronic tissue destructive diseases. The present study was performed to examine whether SMTP-7 is effective for the amelioration or protection of early-stage IgA nephropathy (IgAN) induced by nivalenol (NIV) in female BALB/c mice. In Experiment 1, mice were administered NIV at 24 ppm in diet for 8 weeks, and during the NIV treatment, they were intraperitoneally injected with SMTP-7 (10 mg/kg) three times a week. In Experiment 2, mice were injected similarly with SMTP-7 during the last 4 weeks of a 16-week NIV treatment. Immunofluorescence analysis revealed an inhibitory effect of SMTP-7 on the glomerular deposition of IgA in Experiment 1; however, it was ineffective in Experiment 2. On the other hand, SMTP-7 did not affect the serum concentration of IgA in both experiments. These results suggest that SMTP-7 has a potential to decrease the progression of IgAN induced by NIV through inhibition of local accumulation of IgA in the glomerular mesangium, while it was ineffective for suppression of IgA production. On the other hand, SMTP-7 was found to be ineffective for already deposited IgA, suggesting that SMTP-7 may not be effective for ameliorating advanced IgAN.  相似文献   

Benzodiazepines inhibit the acetylcholine receptor-operated potassium current (IK.ACh) by different mechanisms in guinea-pig atrial myocytes     

Okada M  Mizuno W  Nakarai R  Matada T  Yamawaki H  Hara Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2012,74(7):879-884

The anticholinergic effects of 7 benzodiazepines, bromazepam, camazepam, chlordiazepoxide, diazepam, lorazepam, medazepam and triazolam, were compared by examining their inhibitory effects on the acetylcholine receptor-operated potassium current (I(K).(ACh)) in guinea-pig atrial myocytes. All of these benzodiazepines (0.3-300 μM) inhibited carbachol (1 μM)-induced I(K).(ACh) in a concentration-dependent manner. The ascending order of IC(50) values for carbachol-induced I(K).(ACh) was as follows; medazepam, diazepam, camazepam, triazolam, bromazepam, lorazepam and chlordiazepoxide (>300 μM). The compounds, except for bromazepam, also inhibited I(K).(ACh) activated by an intracellular loading of 100 μM guanosine 5'-[γ-thio]triphosphate (GTPγS) in a concentration-dependent manner. The ascending order of IC(50) values for GTPγS-activated I(K).(ACh) was as follows; medazepam, diazepam, camazepam, lorazepam, triazolam chlordiazepoxide (>300 μM) and bromazepam (>300 μM). To clarify the molecular mechanism of the inhibition, IC(50) ratio, the ratio of IC(50) for GTPγS-activated I(K).(ACh) to carbachol-induced I(K).(ACh), was calculated. The IC(50) ratio for camazepam, diazepam, lorazepam, medazepam and triazolam was close to unity, while it for chlordiazepoxide could not be calculated. These compounds would act on the GTP binding protein and/or potassium channel to achieve the anticholinergic effects in atrial myocytes. In contrast, since the IC(50) ratio for bromazepam is presumably much higher than unity judging from the IC(50) values (104.0 ± 30.0 μM for carbachol-induced I(K).(ACh) and >300 μM for GTPγS-activated I(K).(ACh), it would act on the muscarinic receptor. In summary, benzodiazepines had the anticholinergic effects on atrial myocytes through inhibiting I(K).(ACh) by different molecular mechanisms.  相似文献   

The influence and impact of tsunamis on the microorganism assembly of Nagatsura-Ura Lagoon,Miyagi, northeastern Japan     

Okumura  Yutaka  Matsuoka  Hiromi  Arakawa  Hisayuki  Tokanai  Fuyuki  Suzuki  Atsushi  Irizuki  Toshiaki  Kajita  Hiroto  Hara  Motoyuki 《Fisheries Science》2021,87(1):121-130

Fisheries Science - Two sediment cores were collected from two sites in Nagatsura-Ura Lagoon, the mouth of which was destroyed in the 2011 Tohoku-oki tsunami. Although sediment conditions differed...  相似文献   

Expression of genes related to corticotropin production and glucocorticoid feedback in corticotroph adenomas of dogs with Cushing's disease     

Teshima T  Hara Y  Takekoshi S  Teramoto A  Osamura RY  Tagawa M 《Domestic animal endocrinology》2009,36(1):3-12

Cushing's disease caused by pituitary corticotroph adenoma is a common endocrine disease in dogs. A characteristic biochemical feature of corticotroph adenomas is their relative resistance to negative feedback by glucocorticoids. In this study, we examined gene expression related to adrenocorticotropic hormone (ACTH) production and secretion, and the negative feedback by glucocorticoids in canine corticotroph adenoma. We used resected corticotroph adenomas from 10 dogs with Cushing's disease. In order to investigate the alteration of gene expression between corticotroph adenoma and normal corticotrophic cells, ACTH-positive cells in the anterior lobe were microdissected using a laser-capture microdissection system, and mRNA levels of proopiomelanocortin (POMC), corticotropin releasing hormone receptor 1 (CRHR1), glucocorticoid receptor (GR), mineralocorticoid receptor (MR), and 11 beta hydroxysteroid dehydrogenase (11HSD) type 1 and type 2 were determined using real-time RT-PCR. POMC, CRHR1, and 11HSD2 mRNA levels in corticotroph adenoma were greater than those in normal corticotrophic cells (POMC, 5.5-fold; CRHR1, 4.9-fold; 11HSD2, 4.2-fold, P<0.01, respectively). MR and 11HSD1 mRNA levels in corticotroph adenoma were lower than those in normal corticotrophic cells (MR, 2.2-fold; 11HSD1, 2.9-fold, P<0.01, respectively). GR mRNA levels did not differ between corticotroph adenoma and normal corticotrophic cells. Our results may help to understand the increased ACTH production and the resistance to negative feedback suppression by glucocorticoids in canine corticotroph adenomas. These changes in gene expression may have a role in the growth of canine corticotroph adenoma, and help elucidate the pathophysiology of dogs with Cushing's disease.  相似文献