scholarly journals Model System for Growing and Quantifying Streptococcus pneumoniae Biofilms In Situ and in Real Time

2004 ◽  
Vol 70 (8) ◽  
pp. 4980-4988 ◽  
Author(s):  
R. M. Donlan ◽  
J. A. Piede ◽  
C. D. Heyes ◽  
L. Sanii ◽  
R. Murga ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Extracellular Polymeric Substances ◽  
Viable Cell ◽  
Protein Band ◽  
Biofilm Reactor ◽  
Cell Counts ◽  
Biofilm Structure ◽  
Kinetics Of ◽  
Over Time

ABSTRACT Streptococcus pneumoniae forms biofilms, but little is known about its extracellular polymeric substances (EPS) or the kinetics of biofilm formation. A system was developed to enable the simultaneous measurement of cells and the EPS of biofilm-associated S. pneumoniae in situ over time. A biofilm reactor containing germanium coupons was interfaced to an attenuated total reflectance (ATR) germanium cell of a Fourier transform infrared (FTIR) laser spectrometer. Biofilm-associated cells were recovered from the coupons and quantified by total and viable cell count methods. ATR-FTIR spectroscopy of biofilms formed on the germanium internal reflection element (IRE) of the ATR cell provided a continuous spectrum of biofilm protein and polysaccharide (a measure of the EPS). Staining of the biofilms on the IRE surface with specific fluorescent probes provided confirmatory evidence for the biofilm structure and the presence of biofilm polysaccharides. Biofilm protein and polysaccharides were detected within hours after inoculation and continued to increase for the next 141 h. The polysaccharide band increased at a substantially higher rate than did the protein band, demonstrating increasing coverage of the IRE surface with biofilm polysaccharides. The biofilm total cell counts on germanium coupons stabilized after 21 h, at approximately 105 cells per cm2, while viable counts decreased as the biofilm aged. This system is unique in its ability to detect and quantify biofilm-associated cells and EPS of S. pneumoniae over time by using multiple, corroborative techniques. This approach could prove useful for the study of biofilm processes of this or other microorganisms of clinical or industrial relevance.

scholarly journals Comparison of viable cell counts and fluorescence in situ hybridization using specific rRNA-based probes for the quantification of human fecal bacteria

2000 ◽  
Vol 183 (1) ◽  
pp. 125-129 ◽  
Author(s):  
H.J.M. Harmsen ◽  
G.R. Gibson ◽  
P. Elfferich ◽  
G.C. Raangs ◽  
A.C.M. Wildeboer-Veloo ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Viable Cell ◽  
Fecal Bacteria ◽  
Cell Counts

scholarly journals Evaluation of T-3811ME (BMS-284756), a New Des-F(6)-Quinolone, for Treatment of Meningitis Caused by Penicillin-Resistant Streptococcus pneumoniae in Rabbits

2002 ◽  
Vol 46 (6) ◽  
pp. 1760-1765 ◽  
Author(s):  
Masahiro Takahata ◽  
Hiroshi Yamada ◽  
Teiichi Morita ◽  
Shinichi Furubou ◽  
Shinzaburo Minami ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Viable Cell ◽  
Treated Group ◽  
Dependent Manner ◽  
Free Base ◽  
Time Curve ◽  
Gram Positive Bacteria ◽  
Cell Counts ◽  
Concentration Time ◽  
Dose Dependent

ABSTRACT T-3811ME (BMS-284756) is a new des-F(6)-quinolone with high levels of activity against gram-positive bacteria, including penicillin-resistant Streptococcus pneumoniae (PRSP) strains. T-3811, the free base of T-3811ME, exhibited potent activity against 28 clinical strains of PRSP isolated clinically (MIC at which 90% of the isolates tested are inhibited, 0.0625 μg/ml). After the intravenous dosing of T-3811ME (20 mg/kg of body weight as T-3811) in rabbits with meningitis caused by PRSP, the area under the concentration-time curve (AUC) of T-3811 in cerebrospinal fluid (CSF) was 5.79 μg · h/ml and was 4.5-fold higher than that of T-3811in the CSF of rabbits without meningitis. In addition, the AUC/MIC for T-3811ME (20 mg/kg as T-3811) in CSF was 185, which was 4.3-fold higher than that for ceftriaxone (administered intravenously at 100 mg/kg). After the administration of any dose of T-3811ME (5, 10, and 20 mg/kg as T-3811), the viable cell counts in CSF decreased in a dose-dependent manner. In particular, after dosing of 20 mg/kg (as T-3811), the viable cell counts in CSF were significantly less than those in the nontreated group (P < 0.01). By histopathological evaluation, 6 h after the administration of T-3811ME (20 mg/kg as T-3811), the thickening of the cerebral meninx and the infiltration of neutrophils into the cerebral meninx were less severe in the treated group than in the nontreated group. T-3811ME (BMS-284756) may be expected to be evaluated for the management of meningitis caused by highly penicillin-resistant pneumococci.

Nucleocytoplasmic transport and distribution of an amino acid, in situ

1975 ◽  
Vol 19 (1) ◽  
pp. 127-139
Author(s):  
M. Frank ◽  
S.B. Horowitz
Keyword(s):  
Amino Acid ◽  
Low Temperature ◽  
Nucleocytoplasmic Transport ◽  
Acid Transport ◽  
Solute Exclusion ◽  
Kinetics Of Uptake ◽  
Nucleocytoplasmic Distribution ◽  
Kinetics Of ◽  
Over Time

Ultra-low temperature techniques (microdissection and autoradiography) were used to study the nucleocytoplasmic distribution and transport of alpha-aminoisobutyric acid (AIB) in an amino acid-accumulating cell. In amphibiam oocytes incubated in AIB, the nuclear concentration of this non-metabolizable amino acid exceeds the cytoplasmic concentration by 45%, remaining constant both over time and variation in substrate concentration. The kinetics of uptake suggest that this nucleo-cytoplasmic asymmetry arises from solubility differences between the 2 compartments, and that the nuclear envelope plays a negligible role in amino acid transport. A solute exclusion model is offered to explain the nucleocytoplasmic asymmetry.

scholarly journals The Joint Effect of pH Gradient and Glucose Feeding on the Growth Kinetics of Lactococcus lactis CECT 539 in Glucose-Limited Fed-Batch Cultures

2019 ◽  
Vol 68 (2) ◽  
pp. 269-280
Author(s):  
MÓNICA COSTAS MALVIDO ◽  
ELISA ALONSO GONZÁLEZ ◽  
RICARDO J. BENDAÑA JÁCOME ◽  
NELSON PÉREZ GUERRA
Keyword(s):  
Lactococcus Lactis ◽  
Viable Cell ◽  
Product Formation ◽  
Ph Gradient ◽  
Feeding Strategies ◽  
Fed Batch ◽  
Batch Cultures ◽  
Cell Counts ◽  
First Time ◽  
Kinetics Of

Two glucose-limited realkalized fed-batch cultures of Lactococcus lactis CECT 539 were carried out in a diluted whey medium (DW) using two different feeding media. The cultures were fed a mixture of a 400 g/l concentrated lactose and a concentrated mussel processing waste (CMPW, 101.72 g glucose/l) medium (fermentation I) or a CMPW medium supplemented with glucose and KH2PO4 up to concentrations of 400 g glucose/l and 3.21 g total phosphorus/l, respectively (fermentation II). For an accurate description and a better understanding of the kinetics of both cultures, the growth and product formation by L. lactis CECT 539 were both modelled, for the first time, as a function of the amounts of glucose (G) added and the pH gradient (VpH) generated in every realkalization and feeding cycle, by using an empirical polynomial model. With this modeling procedure, the kinetics of biomass, viable cell counts, nisin, lactic acid, acetic acid and butane-2,3-diol production in both cultures were successfully described (R2 values > 0.970) and interpreted for the first time. In addition, the optimum VpH and G values for each product were accurately calculated in the two realkalized fed-batch cultures. This approach appears to be useful for designing feeding strategies to enhance the productions of biomass, bacteriocin, and metabolites by the nisin-producing strain in wastes from the food industry.

Melting Agar by Microwave Energy

1984 ◽  
Vol 47 (10) ◽  
pp. 770-772 ◽  
Author(s):  
DANIEL Y. C. FUNG ◽  
C. C. SHEREE LIN
Keyword(s):  
Room Temperature ◽  
Viable Cell ◽  
Microwave Treatment ◽  
Microwave Oven ◽  
Melting Time ◽  
Liquid Form ◽  
Cell Counts ◽  
Conventional Boiling ◽  
Composite Data

The microwave oven is very convenient for melting agar for viable cell counts. Composite data of four microwave ovens indicated that melting time for 50 ml of agar per bottle was about 1 min for one bottle, 1.5 min for two bottles, and 2.5 min for four bottles heated simultaneously. Melting time for 100 ml of agar per bottle was about 1.5 min for one bottle, 2.5 min for two bottles, and 4 min for four bottles. Melting times of agar in square or flat bottles were similar. Agar melted by microwave treatment performed in viable cell counts equally as well as agar melted by the conventional boiling method. Even after prolonged (50% longer than melting time) microwave treatment, performance of the agar remained unchanged. Agar melted by microwave treatment can remain in liquid form (48°C) in situ for about 30 min (50 ml) and 1 h (100 ml). When removed from the microwave oven immediately after melting, the agar remained in liquid form (48°C) at room temperature for about 25 min (50 ml) and 40 min (100 ml). The microwave oven is highly efficient in melting agar without detrimental effects on the performance of agar.

Superiority of IFN Versus HU Using a Novel Biomarker-Based Tool for Assessment of Disease Burden in MPNs

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2972-2972 ◽  
Author(s):  
Vibe Skov ◽  
Marc JB Dam ◽  
Rasmus K Pedersen ◽  
Morten Andersen ◽  
Trine Alma Knudsen ◽  
...  
Keyword(s):  
Lactic Dehydrogenase ◽  
Large Majority ◽  
Data Driven ◽  
Allele Burden ◽  
Platelet Counts ◽  
Cell Counts ◽  
Using Data ◽  
Kinetics Of ◽  
Over Time ◽  
Jak2v617f Allele Burden

Background: Treatment of polycythemia vera (PV) patients with hydroxyurea (HU) normalizes elevated blood cell counts within weeks in the large majority of patients. Studies on the impact of HU upon the kinetics of the JAK2V617F allele burden, leukocyte and platelets over time are scarce, and results have been reported highly heterogeneous. Purpose: Using data driven analysis as a novel tool to model the kinetics of the JAK2V617F allele burden and blood cell counts over time during treatment with HU. Material and Methods: Using serial measurements of JAK2V617F and correlation analyzes of routine hematological values (Hb-concentration, leukocyte count, platelet count, lactic dehydrogenase), we present a detailed description and analysis of the kinetics of the JAK2V617F, leukocyte and platelet counts and lactic dehydrogenase in 29 PV patients who were followed in the Danish randomized trial (DALIAH) comparing the efficacy of pegylated interferon-alpha2 (IFN) versus HU in patients older than 60 years. Results: Response patterns were highly heterogeneous. In the large majority of patients, HU treatment was initially associated with a modest decline in the JAK2V617F allele burden in concert with a decline in leukocyte and platelet counts. However, HU did not induce a sustained and continuous decrease in the JAK2V617F allele burden in any patient as previously reported in patients being treated with IFN. Importantly, HU treatment was neither able to induce a sustained normalization of elevated leukocyte and platelet counts, although counts were temporarily normalized in most patients during the first months of therapy. The fluctuating leukocyte and platelet counts contrast the sustained normalization of cell counts in the large majority of patients during long term treatment with IFN. Discussion and Conclusions: Using data-driven analysis of the JAK2V617F allele burden, leukocyte and platelet kinetics during treatment with HU, we have shown that HU does not induce a sustained decrease in the JAK2V617F allele burden and neither induces sustained normalization of elevated cell counts in PV patients. Our results may explain why PV patients during treatment with HU still have a substantially increased risk of thrombosis. Based upon our previous and present findings, obtained by mathematical modelling and data driven analysis studies, a rational and cost-effective treatment might be a combination therapy of HU and IFN, both being used for decades in the treatment of PV but according to the findings in our studies now being proposed to be combined in the initial treatment period, since their combined effects might be highly efficacious and are foreseen to have the potential to minimize the risk of thrombosis and bleeding. By these studies, we have also proven mathematical modelling and data driven analysis to be highly important tools to decipher novel treatment modalities for patients suffering from MPN cancers but likely other cancers as well. Disclosures Hasselbalch: Novartis: Research Funding; AOP Orphan Pharmaceuticals: Other: Data monitoring board. OffLabel Disclosure: Interferon-alpha2 for the treatment of myeloproliferative neoplasms.

scholarly journals Mineral Precipitation in Fractures and Nanopores within Shale Imaged Using Time-Lapse X-ray Tomography

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 480 ◽  
Author(s):  
Godinho ◽  
Ma ◽  
Chai ◽  
Storm ◽  
Burnett
Keyword(s):  
Time Lapse ◽  
Growth Front ◽  
Barium Sulphate ◽  
General Sequence ◽  
X Ray ◽  
Sequence Of Events ◽  
Subsurface Engineering ◽  
Kinetics Of ◽  
Over Time

Barite precipitation in fractures and nanopores within a shale sample is analysed in situ, in 3D, and over time. Diffusion of barium and sulphate from opposite sides of the sample creates a supersaturated zone where barium sulphate crystals precipitate. Time-lapse synchrotron-based computed tomography was used to track the growth of precipitates over time, even within the shale’s matrix where the nanopores are much smaller than the resolution of the technique. We observed that the kinetics of precipitation is limited by the type and size of the confinement where crystals are growing, i.e., nanopores and fractures. This has a major impact on the ion transport at the growth front, which determines the extent of precipitation within wider fractures (fast and localised precipitation), thinner fractures (non-localised and slowing precipitation) and nanopores (precipitation spread as a front moving at an approximately constant velocity of 10 ± 3 µm/h). A general sequence of events during precipitation in rocks containing pores and fractures of different sizes is proposed and its possible implications to earth sciences and subsurface engineering, e.g., fracking and mineral sequestration, are discussed.

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

Growth kinetics of Al2Cu in an Al-1.5Cu thin film by in Situ TEM

1993 ◽  
Vol 51 ◽  
pp. 1172-1173
Author(s):  
M. Park ◽  
S.J. Krause ◽  
S.R. Wilson
Keyword(s):  
Thin Film ◽  
In Situ Tem ◽  
Collector Plate ◽  
Transmission Electron ◽  
Device Processing ◽  
Corrosion Susceptibility ◽  
Precipitation Phenomena ◽  
Semiconductor Chips ◽  
Kinetics Of

Cu alloying in Al interconnection lines on semiconductor chips improves their resistance to electromigration and hillock growth. Excess Cu in Al can result in the formation of Cu-rich Al2Cu (θ) precipitates. These precipitates can significantly increase corrosion susceptibility due to the galvanic action between the θ-phase and the adjacent Cu-depleted matrix. The size and distribution of the θ-phase are also closely related to the film susceptibility to electromigration voiding. Thus, an important issue is the precipitation phenomena which occur during thermal device processing steps. In bulk alloys, it was found that the θ precipitates can grow via the grain boundary “collector plate mechanism” at rates far greater than allowed by volume diffusion. In a thin film, however, one might expect that the growth rate of a θ precipitate might be altered by interfacial diffusion. In this work, we report on the growth (lengthening) kinetics of the θ-phase in Al-Cu thin films as examined by in-situ isothermal aging in transmission electron microscopy (TEM).

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