SEARCH · PubMed Health

Results for “Condensates”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources

PubMed1989

Disinfection with gaseous formaldehyde. First Part: Bactericidal and sporicidal effectiveness of formaldehyde with and without formation of a condensing layer.

Suspensions of Staphylococcus aureus ATCC 6538, Streptococcus faecium ATCC 6057, and of spores of Bacillus subtilis var. niger DSM 675 dried on polished stainless steel carriers were exposed in a model chamber to 3.2 mg HCHO l-1 air at temperatures of 20, 25, 30, 35 and 40 degrees C and the kinetics of their inactivation were determined by successive colony counting during the exposures. The HCHO treatment was carried out once with the formation of a condensing layer on the carriers and once without recondensation, at a RH of about 90%. In both procedures the cells or spores were suspended and dried in saline peptone water and additionally, in the case of the exposure without condensate layer, suspended in peptone water only. For S. aureus and S. faecium, significant differences between the two processes were only observed at 20 degrees C, whereby S. aureus showed for example a D-value of 14.8 minutes and after an exposure with condensate a D-value of 28.1 min. However at higher temperatures the effectiveness of HCHO in gaseous or condensate form was rather similar. At 35 degrees C the D-values after exposure to HCHO in condensate and gaseous form was for S. aureus 4.1 min and 5.9 min respectively, whereas after treatment at 40 degrees C D-values of 3.2 min and 3.8 min respectively were determined. At 35 and 40 degrees C D-values for S. aureus suspended in peptone water and exposed to gaseous HCHO were 50% lower than when suspended in saline peptone water. At lower exposure temperatures large differences were not registered. For the B. subtilis spores exposure to formaldehyde without condensation showed D-values of 34.8 and 5.6 min at 20 and 40 degrees C respectively. These are 8- and 4-fold lower than those of a corresponding exposure with a condensing layer. No D-value differences were observed for spores suspended and dried in saline peptone water or in peptone water after exposures to gaseous formaldehyde.

Aerosols↗

PubMed1986

[Differential condensation of human chromosomes 9 and Y].

Some differences were observed in the mitotic condensation of regions composing human chromosomes 9 and Y: regions 9p, 9h and Y nf are characterized by an intense condensation by the end of the spiralization interval studied (the length of the repair chromosome 3 varying from 5.4 to 2.9 mkm). At the same time, the condensation of regions 9q-h (region 9q without heterochromatic block) is slowing in the initial spiralization interval (the length of chromosome 3 varying from 16.6 to 5.5 mkm). The Yf-block of Y-chromosome is condensing faster than nf-region. The condensation parameters of Q-heterochromatic blocks are most variable while the euchromatic regions are most stable. The dynamics of 9h and of f-block condensation are independent within one karyotype. Based on the data obtained we doubt the correctness of studies on linear dimensions of the constitutive heterochromatin blocks for the evaluation of its quantity in the karyotype. A possible association of differential mitotic condensation with the chromosome segregation disturbances is discussed.

Chromosome Banding↗

PubMed1985

N-acetylcysteine protection against the toxicity of cigarette smoke and cigarette smoke condensates in various tissues and cells in vitro.

The protective effect of N-acetylcysteine on the toxicity of tobacco smoke condensates was investigated using different cellular in vitro systems. Cigarette smoke condensates, and the non-volatile and semi-volatile fractions separated from the condensate were used. All three smoke condensate fractions were toxic to isolated rat hepatocytes and lung cells and caused a loss of cell membrane integrity. A rapid depletion of cellular reduced glutathione (GSH) preceded the toxicity. The loss of GSH was due to conjugation of reactive compounds in the condensate fractions and not to oxidation since no increase in oxidized glutathione (GSSG) could be observed. N-acetylcysteine at a concentration of 1 mM protected both from the GSH loss and cell toxicity caused by the condensate fractions. The effect of the tobacco smoke condensate on the colony forming efficiency (CFE) of cultured human bronchial cells was also investigated. Already at concentrations of 50 micrograms/ml the survival decreased to 40% of control and at 100 micrograms/ml almost no cells formed colonies. N-acetylcysteine substantially increased survival when added at 10 mM concentration.

Acetylcysteine↗

PubMed1984

Contaminated condensate in mechanical ventilator circuits. A risk factor for nosocomial pneumonia?

We studied ventilator circuit colonization and condensate formation in 30 mechanical ventilators during the first 24 h after a circuit change. Parts of the circuit nearest the patient were more frequently contaminated and had the highest levels of colonization. There was rapid colonization of tubing after a circuit change; 33% of the ventilators were colonized at 2 h, 64% at 12 h, and 80% at 24 h. The median level of colonization at 24 h was 7 X 10(4) organisms/ml. Water condensate collected in the ventilator circuits at a mean rate of 30 ml/h (range, 10 to 60 ml/h). At 24 h, 80% of the condensate samples were contaminated at a median level of 2 X 10(5) organisms/ml. The bacteria isolated from the condensate usually correlated with organisms previously isolated from the patient's sputum, suggesting that the patient's oropharyngeal flora is the primary source of circuit colonization. Highly contaminated condensate in the ventilator circuit may be a significant risk factor for nosocomial pneumonia. We suggest that circuit condensate be emptied regularly, handled as infectious waste, and that special efforts be taken to prevent contaminated condensate from inadvertently washing into the patient's tracheobronchial tree.

Bacterial Infections↗

PubMed1995

[Determination of lead (II) in food using the ICP-AES method after condensation on the lanthanum carrier].

The purpose of the study was utilization of emission atomic absorption spectrometry with excitation in induction-coupled plasma, and molecular spectrometry for determination of lead in milk and dairy products after condensation in ammonia atmosphere. Two methods were proposed for lead condensation on lanthanum carrier--in form of hydroxide or sulphide. By coprecipitation of lead on lanthanum in ammonia atmosphere lead separated and selectively condensed. Other metals (Zn, Cd, Cu) coexistent in food products remained as amino complexes in the solution. The sediment remaining after lead condensation was dissolved in 2 mol/dm3 hydrochloric acid solution. The selected conditions of lead separation and condensation make possible determination of the metal in the concentrations from 0.01 mcg/ml to 0.2 mcg/ml by the ICP-ARS and dithizone methods. The method of condensation and determination was used for lead determination in milk and dairy products in concentrations below 1.5 x 10(-5)%. The studied food products were mineralized with concentrated HNO3, H2SO4 and perhydrol. This mineralization method makes it possible to determine in one mineralisate directly copper and zinc by ICP-ARS and dithizone methods, and lead after condensation. The obtained results were precise and reproducible.

Animals↗

PubMed1998

Induction of DNA adducts in vivo in rat lung cells by fume condensates of roofing asphalt.

Many workers in the highway construction and roofing industries are potentially exposed to asphalt fumes. However, little is known regarding the carcinogenic hazards of these fumes to the exposed workers. Previous studies have shown that condensates of asphalt fumes are weakly mutagenic to bacteria and are capable of inducing micronucleus formation in cultured mammalian cells. In this study, the induction of DNA adducts in vivo in lung and white blood cells (WBCs) of rats by fume condensates of type I and type III roofing asphalts was investigated using 32P-postlabeling analysis. Male CD rats (3/group) received 3 intratracheal instillations of fume condensates in a 24-h period. DNA from both lung cells and WBCs were isolated and used to detect DNA adducts. Condensates of both roofing asphalt fumes caused DNA adduct formation in rat lung cells in a similar dose-related manner. Under the conditions studied, however, neither type I nor type III fume condensate induced DNA adducts in WBCs. These results indicate that 1) condensates of fumes from both type I and type III have similar genotoxic activity, 2) chemicals in the condensates of roofing asphalt fumes can covalently bind to the DNA of rat lung cells, and 3) WBCs may not be a suitable surrogate for lung cells in DNA adduct studies of workers exposed to roofing asphalt fumes.

Animals↗

PubMed2026

Emergent 3D genome reorganization and graded gene control from the stepwise assembly of transcriptional condensates.

Transcriptional condensates are clusters of transcription factors, coactivators, and RNA Pol II associated with gene activation, yet how they assemble and function within the cell remains unclear. Here, we show that transcriptional condensates form in a stepwise manner to enable both graded and three-dimensional (3D) gene control in the yeast heat shock response (HSR). First, the transcription factor Hsf1 (heat shock factor 1) clusters upon partial dissociation from the chaperone Hsp70. Next, the coactivator Mediator partitions following further Hsp70 dissociation and Hsf1 phosphorylation. Finally, Pol II condenses, driving emergent coalescence of HSR genes. Separation-of-function Hsf1 mutants revealed graded (non-switch-like) control of transcription and a decoupling of condensate formation and gene activation. Fully assembled HSR condensates promoted adaptive 3D genome reconfiguration, suggesting a role beyond transcription. In the HSR, differential condensation of the transcriptional machinery quantitatively tunes gene expression and qualitatively remodels the 3D genome.

3D genome↗

PubMed2026

From pan-life phase insights to PhaseHub: Analyzing protein condensate complexity.

Intracellular biomolecular condensation forms multicomponent signaling hubs that regulate development, stress responses, and environmental adaptation. While the molecular grammar encoded within scaffold proteins defines the basal associative features driving condensation, heterotypic condensates are intrinsically dynamic, multicomponent, and far-from-equilibrium systems. Consequently, how condensates organize component composition, stoichiometry, and functional specificity in space and time under physiological conditions remains poorly understood. Addressing this challenge requires integrative frameworks that combine predictive biophysical features with experimental information on protein abundance, interaction networks, subcellular localization, and evolutionary conservation. In this study, we first analyzed phase separation (PS) proteins across the tree of life in 1106 species, revealing a stark contrast in computationally predicted PS propensity between eukaryotes and prokaryotes, with genome size as a key determinant. Through a broad analysis of amino acid homorepeat-containing proteins (HRPs) across all species, we uncovered how PS evolves via a balance between functional condensation and avoidance of harmful, aggregation-prone sequences. We further identified potential signaling hubs and components across kingdoms by integrating PS-positive proteins with experimentally derived abundance and interactome data from four model eukaryotic species. Using Arabidopsis as a model, we dissected the relationships among PS propensity, condensation hub prediction, HRPs, subcellular localization, and structural conservation. Finally, we developed PhaseHub, a user-friendly interface for exploring scaffold-client dynamics, PS components, sequence signatures within each PS protein, and hubs. Collectively, our work provides an evolutionary framework for understanding multicomponent PS hubs by integrating molecular grammar with physiological context, thereby facilitating hypothesis generation and rational design.

Phase Separation↗

PubMed2025

Live-Cell Monitoring and Omics Analysis of Liquid-Solid Transitions of Biomolecular Condensates.

Biomolecular condensates, or so-called membraneless organelles, transition from liquid into more solid-like states over time, contributing to the development of pathological conditions. The present study proposes a simple method using photoactive yellow protein (PYP) and its specific fluorescent covalent ligands to distinguish between the liquid and solid states of protein condensates in live cells. The method, compatible with fluorescence-activated cell sorting (FACS), correlates the stiffness of specific protein condensates with their accessibility to PYP ligands, enabling quantitative multicolor monitoring of condensate solidification. We applied this technique to 12 phase-separating proteins and their mutants, finding that TDP-43, particularly its A315T mutant linked to familial amyotrophic lateral sclerosis, most readily forms solid aggregates. Furthermore, this FACS-compatible strategy enabled the isolation of distinct cell populations based on condensate states, allowing for subsequent proteomic and transcriptomic analyses. Our findings demonstrate that condensate solidification is accompanied by the upregulated expression of extracellular matrix proteins, suggesting a previously unrecognized link between solid aggregate formation and extracellular matrix hardening.

Humans↗

PubMed2026

High-throughput identification of endogenous biomolecular condensates and phase-separating proteins.

Biomolecular condensates formed through liquid-liquid phase separation regulate cellular processes, and their dysregulation causes disease. Current methods for identifying endogenous phase-separating proteins have low throughput and cannot capture dynamic responses to stimuli. Here we present a protocol combining osmotic compression or transforming growth factor-β (TGF-β) treatment to induce condensation with sucrose density gradient centrifugation and quantitative mass spectrometry to enable systematic, high-throughput identification of endogenous condensates and phase-separating proteins. The method exploits the density changes that occur when phase-separating proteins undergo oligomerization during condensate formation. In H1975 cells, we identified over 1,500 phase-separating proteins under osmotic compression or TGF-β treatment; 538 of these candidates were not present in PhaSepDB, a database that compiles in vivo, in vitro and omics-derived proteins. The approach detects constitutive condensates and proteins that dynamically phase-separate in response to osmotic stress or TGF-β signaling. This protocol provides proteome-wide analysis of fractions of proteins having different densities and enables temporal resolution of phase-separation events. The procedure takes ~9 d and requires expertise in cell culture, biochemistry and mass spectrometry. This method enables systematic study of biomolecular condensates and disease-associated phase-separation mechanisms.

Phase Separation↗

PubMed1999

Successive formative stages of precartilaginous mesenchymal condensations in vitro: modulation of cell adhesion by Wnt-7A and BMP-2.

High-density chick limb bud cell culture is a useful model to study mesenchymal condensatifons and chondrogenesis. Most previous studies have focused on the effects of soluble reagents on terminal chondrogenic differentiation and have not defined the early cellular processes and signaling events. In this study, we defined five successive stages in the differentiation process: 1) dissociated cells, 2) small aggregates, 3) formation of cell clusters, 4) precartilaginous condensations, and 5) cartilage nodule. We used RCAS retrovirus-mediated Wnt-7a gene transduction to test the effect of Wnt-7a on the differentiation process. We found that Wnt-7a suppressed chondrogenic differentiation. Wnt-7a did not inhibit the initiation of condensation formation but blocked the progression of precartilaginous condensations to cartilage nodules. The Wnt-7a-transduced cultures showed characteristics of a less mature culture with persistent expression of NCAM, N-cadherin, wider distribution of integrin beta1 and fibronectin, and suppression of tenascin-C. BMP-2 is known to enhance chondrogenic differentiation in these cultures by promoting cell clusters to form continuous sheet-like precartilaginous condensations. However, cultures exposed to both BMP-2 and Wnt-7a showed inhibition of chondrogenic differentiation. Different signaling molecules such as Wnt-7a and BMP-2 may have antagonistic effects on cartilage differentiation and the gradient of the two molecules may be involved in defining the boundaries of the initial precartilaginous condensation. We propose that the shape of the precartilaginous condensations may be modulated by local concentrations of signaling molecules, such as Wnt-7a and BMP-2, which act to alter cell-substrate and cell-cell adhesions.

Animals↗

PubMed2006

Evaluation of the nuclear delivery and intra-nuclear transcription of plasmid DNA condensed with micro (mu) and NLS-micro by cytoplasmic and nuclear microinjection: a comparative study with poly-L-lysine.

BACKGROUND: The efficient nuclear delivery of plasmid DNA (pDNA) is essential for the development of a promising non-viral gene vector. In an attempt to achieve nuclear delivery, NLS-mu, a novel pDNA condenser, was prepared. This consists of mu, a highly potent polypeptide for condensing the pDNA, and a SV40 T antigen-derived nuclear localization signal (NLS(SV40)). METHODS: The utility of NLS-mu was assessed in terms of green fluorescent protein (GFP) expression after cytoplasmic and nuclear microinjection of GFP-encoding pDNA along with the transfection, and compared with mu and poly-L-lysine (PLL). Trans-gene expression after cytoplasmic microinjection was affected by the efficiencies of nuclear transfer and following intra-nuclear transcription. To evaluate the nuclear transfer process separately, we introduced a parameter, a nuclear transfer score (NT score), which was calculated as the trans-gene expression after cytoplasmic microinjection divided by that after nuclear microinjection. RESULTS: As expected, the rank order of trans-gene expression after the transfection and cytoplasmic microinjection was NLS-mu > mu > PLL. However, the calculated NT scores were unexpectedly ranked as mu = NLS-mu > PLL, suggesting that mu, and not NLS(SV40), is responsible for the nuclear delivery of pDNA. In addition, confocal images of rhodamine-labeled pDNA indicated that pDNA condensed with mu and NLS-mu was delivered as a condensed form. In comparing the nuclear transcription, the rank order of trans-gene expression after nuclear microinjection was PLL = NLS-mu > mu, suggesting that intra-nuclear transcription is inhibited by efficient condensation by mu, and is avoided by the attachment of NLS(SV40). CONCLUSIONS: Collectively, NLS-mu, which consists of chimeric functions, is an excellent DNA condenser, and the process is based on mu-derived nuclear transfer and NLS(SV40)-derived efficient intra-nuclear transcription.

Cell Nucleus↗

PubMed1993

Differential chromatin condensation of female and male pronuclei in mouse zygotes.

Mouse zygotes or halves of zygotes, containing either a female or a male pronucleus, were fused with ovulated metaphase II oocytes. In 59.7% of the resulting hybrid cells, the pronuclei underwent premature chromosome condensation (PCC). In some of these heterokaryons the 2 pronuclei differed in the dynamics of condensation. Detectability of differential PCC of pronuclei (dPCC) depended on the type of preparation. In hybrids with PCC, produced by fusion of intact zygotes with metaphase II oocytes and processed for whole-mount preparations, one pronucleus was more advanced in the condensation process in 47% of cases. In air-dried preparations dPCC was detected in as many as 94% of hybrids. Experiments with the fusion of halves of zygotes with metaphase II oocytes have shown that the differential reaction of pronuclei to condensation factor depended on their parental origin. Maternal chromatin responded faster to the condensation factor and attained more advanced stages of PCC than paternal chromatin. Different responses of the maternal and paternal pronucleus to the condensation factor suggests that the 2 pronuclei are not identical with regard to the organization of chromatin and/or the lamin composition of the nuclear envelope.

Animals↗

PubMed2000

Thermodynamics of DNA binding and condensation: isothermal titration calorimetry and electrostatic mechanism.

The thermodynamics of binding of the trivalent cations cobalt hexammine and spermidine to plasmid DNA was studied by isothermal titration calorimetry. Two stages were observed in the course of titration, the first attributed to cation binding and the second to DNA condensation. A standard calorimetric data analysis was extended by applying an electrostatic binding model, which accounted for most of the observed data. Both the binding and condensation reactions were entropically driven (TDeltaS approximately +10 kcal/mol cation) and enthalpically opposed (DeltaH approximately +1 kcal/mol cation). As predicted from their relative sizes, the binding constants of the cations were indistinguishable, but cobalt hexammine had a much greater DNA condensing capacity because it is more compact than spermidine. The dependence of both the free energy of cobalt hexammine binding and the critical cobalt hexammine concentration for DNA condensation on temperature and monovalent cation concentration followed the electrostatic model quite precisely. The heat capacity changes of both stages were positive, perhaps reflecting both the temperature dependence of the dielectric constant of water and the burial of polar surfaces. DNA condensation occurred when about 67 % of the DNA phosphate charge was neutralized by cobalt hexammine and 87 % by spermidine. During condensation, the remaining DNA charge was neutralized.

Binding, Competitive↗

PubMed1982

Extracentromeric connections between sister chromatids demonstrated in human chromosomes induced to condense asymmetrically.

Extracentromeric chromatin fibers were proposed to hold sister chromatids together in mitotic chromosomes examined by electron microscopy, but their existence in living cells has not been demonstrated yet. We have performed an in vitro BrdU-H33258 treatment which induced a differential rate of condensation to each sister chromatid, thus producing asymmetrically condensing chromosomes. The fast condensing chromatid pulled the slower sister one, both bending in parallel. Bent chromatids appeared reciprocally connected by loops of chromatin fibers, suggesting they were the links which permitted the physical interplay between the differently condensing chromatids. When sister chromatid exchanges (SCE) intercalated a fast-condensing fragment in the slow-condensing chromatid or vice versa, the chromosome inverted its curvature at the SCE-point.

Chromatids↗

PubMed1994

Reorganization and condensation of chromatin in mitotic prophase nuclei of Allium cepa.

This paper studies the process and features of chromosome construction in mitotic prophase cells of Allium cepa. The results showed that a prominent reorganization of chromatin occurred during G2--early prophase. The 250-400 nm thick compact chromatin threads in G2 nuclei began to disorganize into about 30, 100 and 220 nm chromatin fibres which constituted the loosely organized chromosome outlines in early prophase before chromosome condensation. In middle prophase, chromosome condensation was characterized by the formation of many condensed regions (aggregates of chromatin), which increased in size (1-1.5 microns) when prophase proceeded. Meanwhile, the chromatin threads that constituted and connected the condensed regions became increasingly thicker (120-250 nm). In late prophase adjacent condensed regions fused to form cylinder-shaped chromosomes. Based on these observations, we come to the conclusion that the construction of prophase chromosomes is a two-step process, that is, the reorganization and condensation of chromatin. In addition, we report the study of silver-stained, DNA- and histone-depleted prophase chromosomes, describe morphological features of the non-histone protein (NHP) residue in early, middle and late prophase chromosomes, and discuss the roles of NHPs in chromosome construction.

Allium↗

PubMed1976

Cyclic condensed metaphosphates and linear polyphosphates in brown and red algae.

The occurrence of linear condensed polyphosphates and cyclic condensed metaphosphates was studied by means of pulse-labeling with 32P-orthophosphate (3--5h) in a number of Phaeophyceae species: Pylaiella litoralis, Ilea fascia, Ectocarpus siliculosus and also Rhodophyceae species: Ceramiumdeslongchampsii, C. rubrum, Rhodomela confervoides, Porphyridium purpureum and P. aerugineum. Two-dimensional cellulose thin layer chromatography revealed that in all species studied 32P-radioactivity was generally present in all oligopolyphosphates containing 2 to 7 phosphate residues, in cyclic metaphosphates (tri-, tetra-, penta- and hexametaphosphates) and in high-molecular-weight condensed phosphates which remained at the starting point. Among the low-molecular-weight condensed inorganic phosphates the trimetaphosphate had a significantly higher specific activity than the other oligophosphates which were separated on the chromatography plates as measured by the direct scanning with a Geiger-Muller counter. The phosphate uptake strongly depends on the internal pool of reserve phosphates of the algae cells. The 32P-orthophosphate incorporation of the cells is low and sluggish when growning in a synthetic medium or in sea water. Accordingly 32P appeared preferentially in the low-molecular-weight fractions of condensed phosphates since the storage phosphates were not yet used. After previous incubation in a P-free culture medium of the algae the 32P was rather rapidly incorporated and was found mostly in the high-molecular-weight condensed phosphates. During MAK-chromatography the high-molecular-weight fractions were eluted together with the nucleic acids (tRNA and DNA) while most of the low-molecular-weight fractions left the column immediately on elution.

Eukaryota↗

PubMed1976

The possible role of solid surface area in condensation reactions during chemical evolution: reevaluation.

Published data on adsorption and condensation of amino acids, purine and pyrimidine bases, sugars, nucleosides, and nucleotides are analyzed in connection with Bernal's hypothesis that clays and other minerals may have provided the most likely surface for adsorption and condensation of these molecules in prebiotic times. Using surface concentration and reaction rate as the main criteria for the feasibility of condensation reactions, four types of prebiotic environments were analyzed: (1) an ocean-sediment system, (2) a dehydrated lagoon bed produced by evaporation, (3) the surface of a frozen sediment, and (4) a fluctuating system where hydration (rainstorms, tidal variations, flooding) and dehysration (evaporation) take place in a cyclic manner. With the possible exception of nucleotides, low adsorption of organomonomers on sediment surfaces of a prebiotic ocean (pH 8) is expected, and significant condensation is considered unlikely. In dehydrated and frozen systems, high surface concentrations are probable and condensation is more likely. In fluctuating environments, condensation rates will be enhanced and the size distribution of the oligomers formed during dehydration may be influenced by a "redistribution mechanism" in which adsorbed oligomers and monomers are desorbed and redistributed on the solid surface during the next hydration-dehydration cycle.

Adsorption↗