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1.
Two-photon scanning laser and confocal microscopies were used to image metabolic dynamics of single or cell populations of Saccharomyces cerevisiae strain 28033. Autofluorescence of reduced nicotinamide nucleotides, and mitochondrial membrane potential (DeltaPsim), were simultaneously monitored. Spontaneous, large-scale synchronized oscillations of NAD(P)H and DeltaPsim throughout the entire population of yeasts occurred under perfusion with aerated buffer in a continuous single-layered film of organisms. These oscillations stopped in the absence of perfusion and the intracellular NAD(P)H pool became reduced. Individual mitochondria within a single yeast also showed in-phase synchronous responses with the cell population, in both tetramethylrhodamine ethyl ester (or tetramethylrhodamine methyl ester) and autofluorescence. A single, localized, laser flash also triggered mitochondrial oscillations in single cells suggesting that the mitochondrion may behave as an autonomous oscillator. We conclude that spontaneous oscillations of S. cerevisiae mitochondrial redox states and DeltaPsim occur within individual yeasts, and synchrony of populations of organisms indicates the operation of an efficient system of cell-cell interaction to produce concerted metabolic multicellular behaviour on the minute time scale in both cases. 相似文献
2.
Yannick?AllanoreEmail author Didier?Borderie Axel?Périanin Hervé?Lemaréchal Ohvanesse?Garabed?Ekindjian André?Kahan 《Arthritis research & therapy》2004,7(1):R93
We have reported previously that dihydropyridine-type calcium-channel antagonists (DTCCA) such as nifedipine decrease plasma
markers of oxidative stress damage in systemic sclerosis (SSc). To clarify the cellular basis of these beneficial effects,
we investigated the effects in vivo and in vitro of nifedipine on superoxide anion (O2
•-) production by peripheral blood monocytes. We compared 10 healthy controls with 12 patients with SSc, first after interruption
of treatment with DTCCA and second after 2 weeks of treatment with nifedipine (60 mg/day). O2
•- production by monocytes stimulated with phorbol myristate acetate (PMA) was quantified by the cytochrome c reduction method. We also investigated the effects in vitro of DTCCA on O2
•- production and protein phosphorylation in healthy monocytes and on protein kinase C (PKC) activity using recombinant PKC.
After DTCCA had been washed out, monocytes from patients with SSc produced more O2
•- than those from controls. Nifedipine treatment considerably decreased O2
•- production by PMA-stimulated monocytes. Treatment of healthy monocytes with nifedipine in vitro inhibited PMA-induced O2
•- production and protein phosphorylation in a dose-dependent manner. Finally, nifedipine strongly inhibited the activity of
recombinant PKC in vitro. Thus, the oxidative stress damage observed in SSc is consistent with O2
•- overproduction by primed monocytes. This was decreased by nifedipine treatment both in vivo and in vitro. This beneficial property of nifedipine seems to be mediated by its cellular action and by the inhibition of PKC activity.
This supports the hypothesis that this drug could be useful for the treatment of diseases associated with oxidative stress. 相似文献
3.
AIMS: To determine the effects of fresh and freeze-dried extracts of Allium sativum on the physiology and morphology of Candida albicans. METHODS AND RESULTS: Inhibition of growth in glucose-yeast extract-peptone was measured using a multiwell plate reader. Scanning and transmission electron microscopy investigations indicated loss of structural integrity. Gas chromatography-mass spectrometry of extracts was employed to separate and quantify putative inhibitory sulphur-containing components. CONCLUSIONS: Fresh garlic extract has a greater efficacy than garlic powder extract as indicated both by its effects on morphology and inhibition of growth. SIGNIFICANCE AND IMPACT OF THE STUDY: The ubiquitous opportunistic pathogen C. albicans is sensitive to garlic; resistance to the broad spectrum of active principles present is unlikely so that its anticandidal effects may provide an important alternative route to chemotherapy. 相似文献
4.
Samaiya A Deo SS Thulkar S Hazarika S Kumar S Parida DK Shukla NK 《World journal of surgical oncology》2005,3(1):3-7
BACKGROUND: Malignant small bowel tumors are very rare and leiomyosarcoma accounts for less than 15% of the cases. Management of these tumors is challenging in view of nonspecific symptoms, unusual presentation and high incidence of metastasis. In this case report, an unusual presentation of jejunal sarcoma and management of liver metastasis with radiofrequency ablation (RFA) is discussed. CASE PRESENTATION: A 45-year-old male presented with anemia and features of small bowel obstruction. Operative findings revealed a mass lesion in jejunum with intussusception of proximal loop. Resection of bowel mass was performed. Histopathological findings were suggestive of leiomyosarcoma. After 3-years of follow-up, the patient developed recurrence in infracolic omentum and a liver metastasis. The omental mass was resected and liver lesion was managed with radiofrequency ablation. CONCLUSION: Jejunal leiomyosarcoma is a rare variety of malignant small bowel tumor and a clinical presentation with intussusception is unusual. We suggest that an aggressive management approach using a combination of surgery and a newer technique like RFA can be attempted in patients with limited metastatic spread to liver to prolong the long-term survival in a subset of patients. 相似文献
5.
JINDŘIŠKA BOJKOVÁ KLÁRA KOMPRDOVÁ TOMÁŠ SOLDÁN SVĚTLANA ZAHRÁDKOVÁ 《Freshwater Biology》2012,57(12):2550-2567
1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area. 相似文献
6.
Moderate alcohol consumption is associated with better endothelial function: a cross sectional study
Keiko Suzuki Mitchell SV Elkind Bernadette Boden-Albala Zhezhen Jin Grace Berry Marco R Di Tullio Ralph L Sacco Shunichi Homma 《BMC cardiovascular disorders》2009,9(1):1-5
Background
Natural heterologous valved conduits with a diameter greater than 22 mm that can be used for right ventricular outflow tract reconstruction in adults are not commercially available. The purpose of this study was to measure by ultrasonography the maximum diameter of the distended jugular veins of horses and cattle, respectively, to identify a population of animals that would be suitable for post-mortem collection of jugular veins at sizes greater than 22 mm.Methods
The study population included 60 Warmblood horses, 25 Freiberger horses, 20 Brown Swiss cows, and 20 Holstein cows (including 10 Holstein and 10 Red Holstein). The maximum cross-sectional diameter of the distended jugular veins was measured at a location half-way between the mandibular angle and the thoracic inlet. The thoracic circumference (heart girth length) was used as a surrogate of body size. The jugular vein diameters of the different populations were compared by analysis of variance and the association between heart girth length and jugular vein diameter was determined in each of the four study populations by linear regression analysis.Results
There was considerable individual variation of jugular vein diameters within each of the four study populations. There was no statistically significant relationship between thoracic circumference and jugular vein diameter in any of the populations. The jugular vein diameters of Brown Swiss cows were significantly larger than those of any of the other populations. Warmblood horses had significantly larger jugular vein diameters compared to Freiberger horses.Conclusion
The results of this study suggest that the production of bovine or equine xenografts with diameters of greater than 22 mm would be feasible. Differences between species and breeds need to be considered. However, prediction of the jugular vein diameter based on breed and heart girth length in an individual animal is inaccurate. 相似文献7.
Thomas GH; Newbern EC; Korte CC; Bales MA; Muse SV; Clark AG; Kiehart DP 《Molecular biology and evolution》1997,14(12):1285-1295
Many structural, signaling, and adhesion molecules contain tandemly
repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin
superfamily of F-actin-crosslinking proteins contains an array of triple
alpha-helical motifs (spectrin repeats). We present here the complete
sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H).
The sequence of beta H supports the origin of alpha- and beta-spectrins
from a common ancestor, and we present a novel model for the origin of the
spectrins from a homodimeric actin-crosslinking precursor. The pattern of
similarity between the spectrin repeat units indicates that they have
evolved by a series of nested, nonuniform duplications. Furthermore, the
spectrins and dystrophins clearly have common ancestry, yet the repeat unit
is of a different length in each family. Together, these observations
suggest a dynamic period of increase in repeat number accompanied by
homogenization within each array by concerted evolution. However, today,
there is greater similarity of homologous repeats between species than
there is across repeats within species, suggesting that concerted evolution
ceased some time before the arthropod/vertebrate split. We propose a
two-phase model for the evolution of the spectrin repeat arrays in which an
initial phase of concerted evolution is subsequently retarded as each new
protein becomes constrained to a specific length and the repeats diverge at
the DNA level. This evolutionary model has general applicability to the
origins of the many other proteins that have tandemly repeated motifs.
相似文献
8.
Comparisons of the molecular evolutionary process at rbcL and ndhF in the grass family (Poaceae) 总被引:2,自引:1,他引:1
We examine rate heterogeneity among evolutionary lineages of the grass
family at two plasmid loci, ndhF and rbcL, and we introduce a method to
determine whether patterns of rate heterogeneity are correlated between
loci. We show both that rates of synonymous evolution are heterogeneous
among grass lineages and that are heterogeneity is correlated between loci
at synonymous sites. At nonsynonymous sites, the pattern of rate
heterogeneity is not correlated between loci, primarily due to an aberrant
pattern of rate heterogeneity at nonsynonymous sites of rbcL. We compare
patterns of synonymous rate heterogeneity to predictors based on the
generation time effect and the speciation rate hypotheses. Although there
is some evidence for generation time effects, neither generation time
effects nor speciation rates appear to be sufficient to explain patterns of
rate heterogeneity in the grass plastid sequences.
相似文献
9.
Oscillatory metabolic activities occur more widely than is generally realised; detectability requires observation over extended times of single yeast cells or synchrony of individuals to provide a coherent population. Where oscillations in intracellular metabolite concentrations are observed, the phenomenon has been ascribed to sloppy control, energetic optimisation, signalling, temporal compartmentation of incompatible reactions, or timekeeping functions. Here we emphasise the consequences of respiratory oscillations as a source of mitochondrially generated reactive O(2) metabolites. Temporal co-ordination of intracellular activities necessitates a time base. This is provided by an ultradian clock, and one result of its long-term operation is cyclic energisation of mitochondria, and thereby the generation of deleterious free radical species. Our hypothesis is that unrepaired cellular constituents and components (especially mitochondria) eventually lead to cellular senescence and apoptosis when a finite number of respiratory cycles has occurred. 相似文献
10.
Respiratory control ratios between 2.0 and 9.0 were obtained by comparison of the respiratory rates of cabbage mitochondria in the presence and in the absence of individual components of the system used to provide ADP and by comparing the rates before and after exhaustion of added ADP. These results indicate that respiration in cabbage mitochondria is controlled by the availability of ADP, which serves as the phosphate acceptor.Pentachlorophenol (PCP), 2,4-dinitrophenol (DNP), gramicidin and oleic acid inhibited phosphorylation to a greater extent than respiration in the cabbage mitochondria, but these reagents did not stimulate respiration in the absence of a phosphate acceptor. Respiration was stimulated by DNP only in the presence of added ATP.2,4-Dinitrophenol, pentachlorophenol, dicumarol and gramicidin did not stimulate ATPase activity either in the presence or absence of added Mg(2+). Oleic acid stimulated ATPase activity in the presence of added Mg(2+), but did not stimulate respiration even in the presence of added ATP.The ATP-(32)Pi exchange rate was increased many fold in the presence of added Mg(2+). Oleic acid and 2,4-dinitrophenol inhibited the exchange almost completely. 相似文献