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51.
Hydroethidine, a reduced form of ethidium bromide, was used as a vital dye in fluorescence assays that allowed visual and semiquantitative monitoring of dye uptake and accumulation by fluorescence microscopy, flow cytometry, image analysis, and microfluorimetry. The excitation and emission filters were chosen to detect hydroethidine and exclude ethidium. Microscopically, there were differences in fluorescence intensities and fluorescence patterns among various tumor cell lines. The fluorescence pattern varied from homogeneous blue in the cytoplasm to blue plus brilliant packets of bluish-white distributed in the cytoplasm. Nuclear staining varied from brown to reddish orange fluorescence. These differences were confirmed by flow cytometry and image analysis. A preliminary survey of various tumors indicated that uptake and accumulation of hydroethidine were dependent on concentration of the dye, duration of cell exposure to the dye, and metabolic state of the cells. Microfluorimetry made possible monitoring of 96 samples in a microculture plate in 30 seconds; thus, this method allows large numbers of samples to be read, with a tremendous savings in time and reagents. The results obtained from the different techniques used were corroborative; therefore, any one of the above techniques may be used in an assay. 相似文献
52.
The present paper adds further notes on the biology of Cyclestheria hislopi (Baird). An attempt has been made to study the variation in the natural population of this species based on its birth-rate. C. hislopi has dist inct preference for the plant Hydrilla verticellata (Royle) on which they remain attached. It is considered completely parthenogenic, having no males. The period from October to January can be considered to be the growth period for this species, after which the population declines. This decline has been found to be due to the low birth-rate exhibited during the subsequent months. 相似文献
53.
Singh RK Mishra RP Jaiswal HK Kumar V Pandey SP Rao SB Annapurna K 《Current microbiology》2006,52(2):117-122
Three novel endophytic rhizobial strains (RRE3, RRE5, and RRE6) were isolated from naturally growing surface sterilized rice
roots. These isolates had the ability to nodulate common bean (Phaseolus vulgaris). Polymerase chain reaction–restriction fragment length polymorphism and sequencing of 16S rDNA of these isolates revealed
that RRE3 and RRE5 are phylogenetically very close to Burkholderia cepacia complex, whereas RRE6 has affinity with Rhizobium leguminosarum bv. phaseoli. Plant infection test using gusA reporter gene tagged construct of these isolates indicated that bacterial cells can go inside and colonize the rice root
interiors. A significant increase in biomass and grain yield was also recorded in greenhouse-grown rice plants inoculated
with these isolates. 相似文献
54.
S. Nayar G.J. Collings S. Bryars 《Journal of experimental marine biology and ecology》2009,373(2):87-95
Productivity measurements from carbon uptake have been suggested as good indicators of the physiological health of seagrasses. As seagrasses acquire carbon from the surrounding water, the rate of uptake often provide a good measure of the efficiency at which seagrasses meet their resource demands for growth. This rate is often used to assess the photosynthetic efficiency of the plants, a proxy for the physiological status of seagrass. This has special relevance to the Adelaide region as over 5000 ha of seagrasses have been lost from Adelaide coastal waters over the last 70 years, with much of this loss attributed to nutrient inputs from wastewater, industrial and stormwater discharges. This study used an in-situ inorganic carbon isotope-labelling and spike approach to obtain ecologically relevant estimates of seasonal variability in carbon uptake and its allocation in two species of temperate seagrass common to this coast (Amphibolis antarctica and Posidonia angustifolia). Uptake of carbon by the seagrass complex (leaves, roots, phytoplankton and epiphytes) was affected by both season and species. Carbon uptake rates of phytoplankton were generally higher than other components of the system. Uptake rates ranged from 0.01 mg C g− 1 DW h− 1 (summer) to 0.61 mg C g− 1 DW h− 1 (spring) in Posidonia and 0.02 mg C g− 1 DW h− 1 (summer) to 0.93 mg C g− 1 DW h− 1 (winter) in Amphibolis. Carbon uptake by the Amphibolis complex was higher than in the Posidonia complex. The Amphibolis complex had higher uptake rates in summer whereas the Posidonia complex was higher in spring. Fine sediments probably from a nearby dredging operation, are likely to have resulted in lower carbon uptake and a reduction in the above-ground and below-ground biomass in summer. 相似文献
55.
This paper describes a single-step method for the biomimetic synthesis of stably suspended magnetite nanoparticles in poly(vinyl alcohol) termed ferrofluids. The challenge is to synthesize water based stable magnetic colloids with a control over the particle size and morphology for biomedical applications. The polymer possibly plays a dual role of a surfactant and a functionalizing agent. Transmission electron microscopy, infrared spectroscopy and vibrating sample magnetometry were used to investigate the properties of the synthesized ferrofluids. It has a strong affinity towards the tryptophan residues in bovine serum albumin protein as determined from the fluorescence emission studies. For in vivo applications this could indirectly mean a resistance to immune response and thus ensure long-term circulation. The ability of the synthesized ferrofluid to bind a che-motherapeutic drug ceftriaxone and its ionic release was observed. The polymer hydroxyl group allows drug-binding and the magnetic property allows targeting to specific sites. Magnetic hybrid fluids with combined advantages of magnetism and polymer open up new perspectives for applications. 相似文献
56.
Olotu A Fegan G Williams TN Sasi P Ogada E Bauni E Wambua J Marsh K Borrmann S Bejon P 《PloS one》2010,5(12):e15569
Background
Febrile malaria is the most common clinical manifestation of P. falciparum infection, and is often the primary endpoint in clinical trials and epidemiological studies. Subjective and objective fevers are both used to define the endpoint, but have not been carefully compared, and the relative incidence of clinical malaria by active and passive case detection is unknown.Methods
We analyzed data from cohorts under active and passive surveillance, including 19,462 presentations with fever and 5,551 blood tests for asymptomatic parasitaemia. A logistic regression model was used to calculate Malaria Attributable Fractions (MAFs) for various case definitions. Incidences of febrile malaria by active and passive surveillance were compared in a subset of children matched for age and location.Results
Active surveillance identified three times the incidence of clinical malaria as passive surveillance in a subset of children matched for age and location. Objective fever (temperature≥37.5°C) gave consistently higher MAFs than case definitions based on subjective fever.Conclusion
The endpoints from active and passive surveillance have high specificity, but the incidence of endpoints is lower on passive surveillance. Subjective fever had low specificity and should not be used in primary endpoint. Passive surveillance will reduce the power of clinical trials but may cost-effectively deliver acceptable sensitivity in studies of large populations. 相似文献57.
Cytologic features of granulosa cell tumors in fluids and fine needle aspiration specimens 总被引:1,自引:0,他引:1
OBJECTIVE: To describe the cytologic features of granulosa cell tumors in fluids and fine needle aspiration specimens, with histologic confirmation. STUDY DESIGN: Histologically confirmed granulosa cell tumors, 6 adult type and 1 juvenile type, were identified. All patients had local recurrences or metastases. Eleven specimens from 7 patients, including cytologic samples, cell blocks and histology, were reviewed. Inhibin immunostaining was performed on cell blocks to aid identification of this group of tumors in the cytologic and histologic samples. RESULTS: The patients were 22-72 years old. Sites included ovary and peritoneum; there were pelvic recurrences and metastatic lesions in the spleen, liver, perirectum and cervical lymph node. Cytologic features of adult granulosa cell tumors included 3-dimensional clusters, resettes loose monolayers and individual cells. Other features were Call-Exner bodies, vacuolated cytoplasm, exuberant capillaries associated with papillarylike fronds, a second population of elongated theca cells, and prominent or rare nuclear grooves. In juvenile granulosa cell tumor the features observed were monolayers, loosely cohesive sheets, single cells, occasional larger pleomorphic cells with nuclear clefting and nuclear protrusions, vacuolated cytoplasm, finely granular chromatin and frequent mitoses. The overall cytologic and histologic correlation was good. Inhibin was focally positive in one peritoneal fluid, correlating with the focal pattern of staining seen on histology. CONCLUSION: A definitive cytologic diagnosis of granulosa cell tumor can be made based on the above criteria. Aggressive tumors are discohesive and show pleomorphism and nuclear protrusions. Inhibin stain may be helpful in identifying granulosa cell tumors in cell block specimens. 相似文献
58.
Reclassification of "atypical" diagnoses in endoscopic retrograde cholangiopancreaticography-guided biliary brushings 总被引:1,自引:0,他引:1
OBJECTIVE: To evaluate the usefulness of reclassifying "atypical" diagnoses in reporting biliary cytology using strict morphologic criteria. STUDY DESIGN: Cytologic specimens from 139 patients (direct, alcohol-fixed smears or cytocentrifuge preparations) were evaluated. Diagnoses were benign (70), atypical (36) and malignant (33). Using strict criteria--major (nuclear contour, chromatin pattern) and minor (polarity, cell types, nuclear size, nuclear grooves, nucleoli, mitosis, nuclear/cytoplasmic [N/C] ratio)--atypical cases were reevaluated and reclassified. Follow-up (F/U) was available on all cases. RESULTS: Atypical cases, (36) were reclassified as malignant (26), atypical favor benign (2)/reactive (3) and atypical, not otherwise specified (NOS) (5). Cases reclassified as malignant showed irregular nuclear contours, chromatin irregularities and rare mitosis. Nuclear enlargement, nucleoli and cellularity varied widely in all groups. N/C ratio was increased in most reclassified malignant cases. All 26 malignant reclassifications correlated with F/U of malignancy. Benign and reactive cases (5) were negative for malignancy on F/U (4), and in 1 case a metastatic carcinoma involving the biliary tree was found. In the 5 atypical (NOS) cases, F/U showed malignancy (3) and pancreatitis (2). Cytocentrifuge preparations made in our laboratory were of superior quality when compared to other methods of cell preparation. CONCLUSION: Irregularities in nuclear membrane and abnormal chromatin pattern were the most consistently useful features correlating with malignancy. The sensitivity and specificity of biliary brush cytology can be enhanced by using strict cytomorphologic criteria and proper collection and fixation, all of which decrease atypical diagnoses. 相似文献
59.
Ikeda RK Miller M Nayar J Walker L Cho JY McElwain K McElwain S Raz E Broide DH 《Journal of immunology (Baltimore, Md. : 1950)》2003,171(9):4860-4867
Few peribronchial mast cells are noted either in the lungs of naive mice or in the lungs of OVA-sensitized mice challenged acutely with OVA by inhalation. In this study, we demonstrate that OVA-sensitized mice exposed to repetitive OVA inhalation for 1-6 mo have a significant accumulation of peribronchial mast cells. This accumulation of peribronchial mast cells is associated with increased expression of the Th2 cell-derived mast cell growth factors, including IL-4 and IL-9, but not with the non-Th2 cell-derived mast cell growth factor, stem cell factor. Pretreating mice with immunostimulatory sequences (ISS) of DNA containing a CpG motif significantly inhibited the accumulation of peribronchial mast cells and the expression of IL-4 and IL-9. To determine whether mast cells express Toll-like receptor-9 (TLR-9; the receptor for ISS), TLR-9 expression by mouse bone marrow-derived mast cells (MBMMCs) was assessed by RT-PCR. MBMMCs strongly expressed TLR-9 and bound rhodamine-labeled ISS. However, incubation of MBMMCs with ISS in vitro neither inhibited MBMMC proliferation nor inhibited Ag/IgE-mediated MBMMC degranulation, but they did induce IL-6. Overall these studies demonstrate that mice exposed to repetitive OVA challenge, but not acute OVA challenge, have an accumulation of peribronchial mast cells and express increased levels of mast cell growth factors in the lung. Although mast cells express TLR-9, ISS does not directly inhibit mast cell proliferation in vitro, suggesting that ISS inhibits accumulation of peribronchial mast cells in vivo by indirect mechanism(s), which include inhibiting the lung expression of Th2 cell-derived mast cell growth factors. 相似文献
60.
Oscillating behavior of carbohydrate granule formation and dinitrogen fixation in the cyanobacterium Cyanothece sp. strain ATCC 51142. 总被引:7,自引:4,他引:3 下载免费PDF全文
It has been shown that some aerobic, unicellular, diazotrophic cyanobacteria temporally separate photosynthetic O2 evolution and oxygen-sensitive N2 fixation. Cyanothece sp. ATCC strain 51142 is an aerobic, unicellular, diazotrophic cyanobacterium that fixes N2 during discrete periods of its cell cycle. When the bacteria are maintained under diurnal light-dark cycles, N2 fixation occurs in the dark. Similar cycling is observed in continuous light, implicating a circadian rhythm. Under N2-fixing conditions, large inclusion granules form between the thylakoid membranes. Maximum granulation, as observed by electron microscopy, occurs before the onset of N2 fixation, and the granules decrease in number during the period of N2 fixation. The granules can be purified from cell homogenates by differential centrifugation. Biochemical analyses of the granules indicate that these structures are primarily carbohydrate, with some protein. Further analyses of the carbohydrate have shown that it is a glucose polymer with some characteristics of glycogen. It is proposed that N2 fixation is driven by energy and reducing power stored in these inclusion granules. Cyanothece sp. strain ATCC 51142 represents an excellent experimental organism for the study of the protective mechanisms of nitrogenase, metabolic events in cyanobacteria under normal and stress conditions, the partitioning of resources between growth and storage, and biological rhythms. 相似文献