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261.
Actin cytoskeleton in intact and wounded coenocytic green algae 总被引:5,自引:0,他引:5
J. W. La Claire II 《Planta》1989,177(1):47-57
Summary The subcellular distribution of actin was investigated in two related species of coenocytic green algae, with immunofluorescence microscopy. Either no, or fine punctate fluorescence was detected in intact cells of Ernodesmis verticillata (Kützing) Børgesen and Boergesenia forbesii (Harvey) Feldmann. A reticulate pattern of fluorescence appears throughout the cortical cytoplasm of Ernodesmis cells shortly after wounding; this silhouettes chloroplasts and small vacuoles. Slender, longitudinal bundles of actin become evident in contracting regions of the cell, superimposed over the reticulum. Thicker portions of the bundles were observed in well-contracted regions, and the highly-convoluted appearance of nearby cortical microtubules indicates contraction of the bundles in these thicker areas. Bundles are no longer evident after healing; only the reticulum remains. In Boergesenia, a wider-mesh reticulum of actin develops in the cortex of wounded cells, which widens further as contractions continue. Cells wounded in Ca2+-free medium do not contract, and although the actin reticulum is apparent, no actin bundles were ever observed in these cells. Exogenously applied cytochalasins have no effect on contractions of cut cells or extruded cytoplasm, and normal actin-bundle formation occurs in treated cells. In contrast, erythro-9-[3-(2-hydroxynonyl)]adenine (EHNA) completely inhibits longitudinal contractions in wounded cells, and few uniformly slender actin bundles develop in inhibited cells. These results indicate that wounding stimulates a Ca2+-dependent, hierarchical assembly of actin into bundles, whose assembly and functioning are inhibited by EHNA. Contraction of the bundles and concomitant wound healing are followed by cessation of motility and disassembly of the bundles. The spatial and temporal association of the bundles with regions of cytoplasmic contraction, indicates that the actin bundles are directly involved in wound-induced cytoplasmic motility in these algae.Abbreviations EHNA
erythro-9-[3-(2-hydroxynonyl)]adenine
- MT(s)
microtubule(s) 相似文献
262.
Long Jin Hyung-Gwan Lee Hyun-Joon La So-Ra Ko Chi-Yong Ahn Hee-Mock Oh 《Antonie van Leeuwenhoek》2014,106(2):319-323
A Gram-negative, aerobic, non-motile, and rod-shaped bacterium, designated strain DS48-5-3T, was isolated from a 48 m sediment sample taken from Daechung Reservoir, Republic of Korea. Comparative 16S rRNA gene sequence studies showed a clear affiliation of this strain to the Bacteroidetes, notably most closely related to Ferruginibacter alkalilentus HU1-GD23T, Ferruginibacter lapsinanis HU1-HG42T and Ferruginibacter yonginensis HME8442T, showing 16S rRNA gene sequence similarities to the type strains of these species of 95.2–96.4 % similarity. The predominant ubiquinone was identified as MK-7. The major fatty acids were identified as iso-C15:0, iso-C17:0 3-OH, and iso-C15:1 G. The G+C content of the genomic DNA of strain DS48-5-3T was determined to be 37.2 %. On the basis of polyphasic evidence, it is proposed that strain DS48-5-3T should belong to a novel species, for which the name Ferruginibacter profundus sp. nov. (type strain DS48-5-3T = KCTC 32478T = JCM 19431T), is proposed. 相似文献
263.
Heather H Burris Andrea A Baccarelli Valeria Motta Hyang-Min Byun Allan C Just Adriana Mercado-Garcia Joel Schwartz Katherine Svensson Martha M Téllez-Rojo Robert O Wright 《Epigenetics》2014,9(8):1083-1091
Worldwide, more than 1 in 10 infants is born prior to 37 weeks gestation. Preterm birth can lead to increased mortality risk and poor life-long health and neurodevelopmental outcomes. Whether environmental risk factors affect preterm birth through epigenetic phenomena is largely unstudied. We sought to determine whether preterm risk factors, such as smoke exposure and education, were associated with cervical DNA methylation in the prostaglandin E receptor 2 gene (PTGER2) and a repetitive element, long interspersed nuclear element-1 Homo sapiens-specific (LINE 1-HS). Second, we aimed to determine whether mid-pregnancy DNA methylation of these regions in cervical samples could predict the length of gestation. We obtained a cervical swab between 16–19 weeks gestation from 80 women participating in a Mexico City birth cohort, used pyrosequencing to analyze DNA methylation of PTGER2 and LINE 1-HS, and examined associations with maternal covariates. We used accelerated failure time models to analyze associations of DNA methylation with the length of gestation. DNA methylation of both sequences was associated with Pap smear inflammation. LINE 1-HS methylation was associated with smoke exposure, BMI and parity. In adjusted models, gestations were 3.3 days longer (95%CI 0.6, 6.0) for each interquartile range of PTGER2 DNA methylation. Higher LINE 1-HS methylation was associated with shorter gestations (-3.3 days, 95%CI -6.5, -0.2). In conclusion, cervical DNA methylation was associated with risk factors for preterm birth and the length of gestation. 相似文献
264.
Over the last two decades, the importance of conserving genetic resources has received increasing attention. In this context
the role of home gardens as repositories of biological diversity has been acknowledged but still a comprehensive, interdisciplinary
investigation of their agro-biodiversity is lacking. Home gardens, whether found in rural or urban areas, are characterized
by a structural complexity and multifunctionality which enables the provision of different benefits to ecosystems and people.
Studies carried out in various countries demonstrate that high levels of inter- and intra-specific plant genetic diversity,
especially in terms of traditional crop varieties and landraces, are preserved in home gardens. Families engage in food production
for subsistence or small-scale marketing and the variety of crops and wild plants provides nutritional benefits. At the same
time, home gardens are important social and cultural spaces where knowledge related to agricultural practices is transmitted
and through which households may improve their income and livelihoods. The present article summarizes available literature
on the biological and cultural significance of agro-biodiversity in home gardens. It discusses future constraints and opportunities
in home garden research, in the prospect of defining and promoting their role in conservation of agricultural biodiversity
and cultural heritage. 相似文献
265.
Nicola Bizzaro Elena Bartoloni Gabriella Morozzi Stefania Manganelli Valeria Riccieri Paola Sabatini Matteo Filippini Marilina Tampoia Antonella Afeltra Giandomenico Sebastiani Claudia Alpini Vittorio Bini Onelia Bistoni Alessia Alunno Roberto Gerli 《Arthritis research & therapy》2013,15(1):R16
Introduction
The diagnostic, predictive and prognostic role of anti-cyclic citrullinated peptide (CCP) antibodies in rheumatoid arthritis (RA) patients is widely accepted. Moreover, detection of these antibodies in subjects presenting with undifferentiated arthritis (UA) is associated with a significant risk to develop the disease. On the other hand, clinical and prognostic significance of evaluating anti-CCP levels in subjects with inflammatory arthritis at disease onset has not been fully clarified. The goal of this prospective study is to analyze the value and prognostic significance of anti-CCP titer quantification in UA subjects.Methods
Serial anti-CCP assays were measured in 192 consecutive patients presenting with UA lasting less than 12 weeks. Clinical and serological data and arthritis outcome were evaluated every 6 months until two years of follow-up.Results
Anti-CCP positivity, at both low and high titer, and arthritis of hand joints significantly predicted RA at two years, risk increasing in subjects with high anti-CCP titers at baseline. Moreover, time to RA diagnosis was shorter in patients with high anti-CCP2 titers at enrollment with respect to those with low antibody concentration.Conclusions
Presence of anti-CCP antibodies, at both low and high concentration, is significantly associated with RA development in subjects with recent onset UA. However, time interval from the onset of the first symptoms to the fulfilment of the classification criteria appears to be directly related to the initial anti-CCP level. 相似文献266.
Giordano A Tonello C Bulbarelli A Cozzi V Cinti S Carruba MO Nisoli E 《FEBS letters》2002,514(2-3):135-140
The intracellular localization and activity of the nitric oxide synthase (NOS) isoforms were investigated in rat brown adipocytes. Immunohistochemistry showed cytoplasmic and nuclear staining for the endothelial NOS (eNOS) and inducible NOS (iNOS) isoforms; accordingly, anti-L-citrulline antibody, a marker of NOS activity, immunostained both the cytoplasm and the nucleus. The presence of metabolically active NOS in the nucleus was further confirmed by immunoblotting analyses of subcellular fractions of homogenates from cultured brown adipocytes and by measurements of NOS activity in the cytosol and nucleus. Sympathetic stimulation in vivo (i.e. cold exposure or beta(3)-adrenergic agonist treatment) and in vitro (i.e. noradrenaline treatment of cultured cells) significantly increased both cytosolic and nuclear eNOS and iNOS expression and activities. By contrast, the number of iNOS-positive, but not eNOS-positive, nuclei was significantly lower in the functionally impaired brown fat of genetically obese Zucker fa/fa rats. These data suggest the existence of a noradrenaline-modulated functional NOS system in the nucleus of brown adipocytes. 相似文献
267.
Silvana Mara Turbino Luz Ribeiro Laís Roquete Lopes Guilherme de Paula Costa Vivian Paulino Figueiredo Deena Shrestha Aline Priscila Batista Roney Luiz de Carvalho Nicolato Fernando Luiz Pereira de Oliveira Juliana Assis Silva Gomes Andre Talvani 《Immunity & ageing : I & A》2017,14(1):6
Background
The current concept of overweight/obesity is most likely related to a combination of increased caloric intake and decreased energy expenditure. Widespread inflammation, associated with both conditions, appears to contribute to the development of some obesity-related comorbidities. Interventions that directly or indirectly target individuals at high risk of developing obesity have been largely proposed because of the increasing number of overweight/obese cases worldwide. The aim of the present study was to assess CXCL16, IL-17, and BMP-2 plasma factors in middle-aged and elderly women and relate them to an overweight or obese status. In total, 117 women were selected and grouped as eutrophic, overweight, and obese, according to anthropometric parameters. Analyses of anthropometric and circulating biochemical parameters were followed by plasma immunoassays for CXCL-16, IL-17, and BMP-2.Results
Plasma mediators increased in all overweight and obese individuals, with the exception of BMP-2 in the elderly group, whereas CXCL16 levels were shown to differentiate overweight and obese individuals. Overweight and/or obese middle-aged and elderly individuals presented with high LDL, triglycerides, and glycemia levels. Anthropometric parameters indicating increased-cardiovascular risk were positively correlated with CXCL-16, BMP-2, and IL-17 levels in overweight and obese middle-aged and elderly individuals.Conclusion
This study provides evidence that CXCL-16, IL-17, and BMP-2 are potential plasma indicators of inflammatory status in middle-aged and elderly women; therefore, further investigation of obesity-related comorbidities is recommended. CXCL16, in particular, could be a potential marker for middle-aged and elderly individuals transitioning from eutrophic to overweight body types, which represents an asymptomatic and dangerous condition.268.
269.
The Common hamster (Cricetus cricetus) has declined by more than 99% in the westernmost part of its range in Belgium, the Netherlands and the adjacent German federal
state of North Rhine-Westphalia (BNN region) during recent decades. Various conservation schemes are ongoing to support the
remaining populations, including restoration of the habitat, captive breeding and reintroductions. One of the factors determining
the success of conservation actions is the genetic constitution of the remaining populations. We therefore measured the genetic
variation in current BNN hamster populations and compared the outcome with the genetic variation in museum samples from the
historical, non-fragmented, population. Most of the current populations have lost the majority of their rare alleles and individual
animals have become nearly homozygous. Since different alleles became fixed in different populations, this has resulted in
strong genetic differentiation between current populations and reflects the strength of drift and inbreeding processes in
small and isolated populations. Despite this differentiation, the total gene diversity of these small populations combined
is not much less than that of the historical population. Hence, the main genetic difference between historical and present
is not in terms of total genetic variation or number of alleles in the BNN region, but in the distribution of this variation
over the populations. 相似文献
270.
Vittorio de Franciscis Vittorio E. Avvedimento Giulia Colletta Vincenzo Zimarino Valeria M. Ursini Fortunato Ciliberto Giancarlo Vecchio 《Experimental cell research》1987,171(2):483-491
We have exploited a recently characterized system of rat thyroid epithelial cells transformed by the wild-type (wt) and a temperature-sensitive (ts) mutant strain of the Kirsten murine sarcoma virus (Ki-MSV) in order to study the effects of the K-ras oncogene on the gene expression of differentiated thyroid epithelial cells. By using cDNAs isolated from normal thyroid glands as probes, we were able to identify three sets of cellular sequences whose expression is influenced by the v-K-ras oncogene. The first set of genes is irreversibly repressed by transformation with both the wt and the ts viruses. The second set of genes is repressed in the ts-Ki-MSV-transformed cells but not in the same cells grown at the nonpermissive temperature. A third set of genes is present at higher levels at the nonpermissive temperature than at the permissive temperature. This system has allowed us to isolate and characterize a number of cDNA clones belonging to each of these three sets of genes. These specific cDNAs are suitable probes to study phenotypical changes during transformation of epithelial cells. 相似文献