A possible mechanism of farnesol tolerance in C. albicans biofilms implemented by activating the PKC signalling pathway and stabilizing ROS levels

2022 ◽  
Vol 71 (1) ◽  
Author(s):  
Shengyan Chen ◽  
Zheng Xu ◽  
Siqi Liu ◽  
Wei Duan ◽  
Yun Huang ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Survival Rates ◽  
Cell Types ◽  
Signalling Pathway ◽  
High Concentration ◽  
Growth State ◽  
Mutant Strains ◽  
Wild Strains ◽  
Multiple Cell ◽  
High Concentrations

Introduction. Biofilms are the natural growth state for most microorganisms. C. albicans biofilms are composed of multiple cell types (round budding yeast-form cells, oval pseudohyphal cells, and elongated hyphal cells) encased in an extracellular matrix. C. albicans biofilms are notorious for resistance to antimicrobial treatments, a property that might be determined by complex mechanisms. Exogenous farnesol exerts a certain antifungal activity against C. albicans with medical implications. Different from other microbes, C. albicans biofilms can tolerate exogenous farnesol at high concentration with some cells still surviving and even maintaining proliferation, but the mechanism is unclear. Hypothesis. The study hypothesizes that C. albicans resists farnesol by activating the PKC signalling pathway. Aim. The study aims to discuss the molecular mechanism of C. albicans resistance to farnesol. Methodology. The ROS levels, the genes and proteins of the PKC pathway were compared between the farnesol-tolerant and non-tolerant groups using ROS levels assay, q-RT PCR and Western blot, respectively. Further, the mutant strains (pkc1Δ/Δ and mkc1Δ/Δ) were constructed, then the survival rates and ROS levels of biofilms exposed to farnesol were compared between mutant and wild strains. The morphological changes were observed using TEM. Results. The survival rates of C. albicans biofilms decreased rapidly under the lower concentration of farnesol (P<0.05), and kept stable (P>0.05) as the concentration rose up to 200 µM. The gene expression of the PKC pathway increased, while ROS levels remained stable and even decreased in the farnesol-tolerant biofilms, compared with those in the farnesol-nontolerant biofilms after farnesol treatment (P<0.05); pkc1 and mkc1 were significantly upregulated by C. albicans during the development of biofilm tolerance to farnesol. The cell wall and cytoplasm of pkc1Δ/Δ and mkc1Δ/Δ were damaged, and the ROS level increased (P<0.05); meanwhile, the survival rate of biofilms decreased compared with that of wild-type strain under the same farnesol concentrations (P<0.05). ROS inhibitors reversed these changes in pkc1Δ/Δ and mkc1Δ/Δ when the mutant strains exposed to farnesol. Conclusion. C. albicans biofilms can tolerate high concentrations of farnesol by activating pkc1 and mkc1 of the PKC pathway and stabilizing ROS levels. The pkc1 and mkc1 are two key genes regulated by C. albicans in the process of biofilm tolerance to farnesol.

scholarly journals Association of beta-cytoplasmic actin with high concentrations of acetylcholine receptor (AChR) in normal and anti-AChR-treated primary rat muscle cultures.

1984 ◽  
Vol 32 (9) ◽  
pp. 973-981 ◽  
Author(s):  
B W Lubit
Keyword(s):  
Acetylcholine Receptor ◽  
Acetylcholine Receptors ◽  
Neuromuscular Junctions ◽  
Morphological Changes ◽  
Muscle Cells ◽  
High Concentration ◽  
Rat Muscle ◽  
Cytoplasmic Actin ◽  
High Concentrations

Previous immunocytochemical studies in which an antibody specific for mammalian cytoplasmic actin was used showed that a high concentration of cytoplasmic actin exists at neuromuscular junctions of rat muscle fibers such that the distribution of actin corresponded exactly to that of the acetylcholine receptors. Although clusters of acetylcholine receptors also are present in noninnervated rat and chick muscle cells grown in vitro, neither the mechanism for the formation and maintenance of these clusters nor the relationship of these clusters to the high density of acetylcholine receptors at the neuromuscular junction in vivo are known. In the present study, a relationship between beta-cytoplasmic actin and acetylcholine receptors in vitro has been demonstrated immunocytochemically using an antibody specific for the beta-form of cytoplasmic actin. Networks of cytoplasmic actin-containing filaments were found in discrete regions of the myotube membrane that also contained high concentrations of acetylcholine receptors; such high concentrations of acetylcholine receptors have been described in regions of membrane-substrate contact. Moreover, when primary rat myotubes were exposed to human myasthenic serum, gross morphological changes, accompanied by an apparent rearrangement of the cytoplasmic actin-containing cytoskeleton, were produced. Although whether the distribution of cytoplasmic actin-containing structures was influenced by the organization of acetylcholine receptor or vice versa cannot be determined from these studies, these findings suggest that in primary rat muscle cells grown in vitro, acetylcholine receptors and beta-cytoplasmic actin-containing structures may be somehow connected.

scholarly journals Application of DNA Shuffling as a Tool for Hydrolase Activity Improvement of Pseudomonas Strain

2020 ◽  
Vol 11 (1) ◽  
pp. 7735-7745
Keyword(s):  
Protein Engineering ◽  
Protoplast Fusion ◽  
Concentration Gradient ◽  
First Generation ◽  
Human Life ◽  
Genome Shuffling ◽  
Dna Shuffling ◽  
High Concentration ◽  
Mutant Strains ◽  
High Concentrations

Biotechnology is considered one of the most influential technologies in various areas of human life, including health, economics, and the environment. Protein engineering is one of the major biotechnology tools in the field of modification and advancement of biocatalysts capabilities. Among the most effective protein engineering methods, in particular, to improve the industrial strain capabilities, is the shuffling genome method. This study aimed to follow knowledge and biocatalysts engineering techniques based on DNA shuffling methods. In the first step, two procedures were followed (DES method and compatibility according to the concentration gradient of Diazinon) to obtain mutant strains. Acquired mutant strains from both methods were resistant to high concentrations of poison up to 3000 mg/L. The activity of these strains also demonstrated their elevated activity compared to parent samples. The highest activity was related to four strains IR1.G1, IR1.D8, IR1.D4, and IR1.D5, which were 0.234 U/ml, 0.1 U/ml, 0.098 U/ml, and 0.066 U/ml, respectively. The improved strain was obtained via the concentration gradient of the diazinon method (IRL1.G1 strain) in comparison with IRL1.D8 strain (owning highest activity through DES method) possesses excessive activity in 3000 mg/L concentration of Diazinon. The evaluated results of first-generation genome shuffling of strains (the first round of protoplast fusion) also indicated that those shuffled strains with the ability to grow in the vicinity of the toxin (3000 mg/L concentration of Diazinon) showed better activity than obtained mutated strains by both methods (concentration gradient of the toxin and the DES method). In the final stage, the best results were related to IRL1.F2, IRL1.F3, and IRL1.F1 shuffled strains with 0.541 mg/L, 0.523 mg/L, and 0.509 mg/L, respectively. The highest activity belonged to the IRL1.F2 genome shuffled strain (first round of protoplast fusion). This strain could grow in a high concentration of toxin, and also, the activity was increased 30, 3.6, and 2.3 times in comparison with the parent strain (IRL1), IRL.D8 mutant, and IRL1.G1, respectively.

scholarly journals Cytokine responses to two common respiratory pathogens in children are dependent on interleukin-1β

2017 ◽  
Vol 3 (4) ◽  
pp. 00025-2017 ◽  
Author(s):  
Alice C-H. Chen ◽  
Yang Xi ◽  
Melanie Carroll ◽  
Helen L. Petsky ◽  
Samantha J. Gardiner ◽  
...  
Keyword(s):  
Cellular Response ◽  
Mononuclear Cells ◽  
Cell Types ◽  
Respiratory Pathogens ◽  
Peripheral Blood Mononuclear ◽  
Multiple Cell ◽  
Ifn Γ ◽  
High Concentrations ◽  
Cellular Immune ◽  
And Control

Protracted bacterial bronchitis (PBB) in young children is a common cause of prolonged wet cough and may be a precursor to bronchiectasis in some children. Although PBB and bronchiectasis are both characterised by neutrophilic airway inflammation and a prominent interleukin (IL)-1β signature, the contribution of the IL-1β pathway to host defence is not clear.This study aimed to compare systemic immune responses against common pathogens in children with PBB, bronchiectasis and control children and to determine the importance of the IL-1β pathway.Non-typeable Haemophilus influenzae (NTHi) stimulation of peripheral blood mononuclear cells (PBMCs) from control subjects (n=20), those with recurrent PBB (n=20) and bronchiectasis (n=20) induced high concentrations of IL-1β, IL-6, interferon (IFN)-γ and IL-10. Blocking with an IL-1 receptor antagonist (IL-1Ra) modified the cellular response to pathogens, inhibiting cytokine synthesis by NTHi-stimulated PBMCs and rhinovirus-stimulated PBMCs (in a separate PBB cohort). Inhibition of IFN-γ production by IL-1Ra was observed across multiple cell types, including CD3+ T cells and CD56+ NK cells.Our findings highlight the extent to which IL-1β regulates the cellular immune response against two common respiratory pathogens. While blocking the IL-1β pathway has the potential to reduce inflammation, this may come at the cost of protective immunity against NTHi and rhinovirus.

scholarly journals Feng-Liao-Chang-Wei-Kang Combined with 5-Fluorouracil Synergistically Suppresses Colitis-Associated Colorectal Cancer via the IL-6/STAT3 Signalling Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Lifan Zhong ◽  
Fan Yang ◽  
Lianfang Gan ◽  
Zhaoxin Yang ◽  
Shuhong Tian ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Cell Types ◽  
Sodium Sulphate ◽  
Signalling Pathway ◽  
Cancer Cell Proliferation ◽  
Multiple Cell ◽  
Stat3 Signalling ◽  
Related Proteins ◽  
Hct116 Cells

Background. Colitis-associated colorectal cancer (CAC) develops from active colonic inflammation, which is characterized by the production of proinflammatory cytokines that can induce mutations. IL-6 is produced by multiple cell types located within the tumor microenvironment including tumor-infiltrating immune cells, stromal cells, and the tumor cells themselves. The aim of our study was to explore the mechanism of Feng-Liao-Chang-Wei-Kang (FLCWK) and 5-fluorouracil (5-FU) in treating CAC. Method. HCT116 cells were treated with 5-FU in the absence or presence of FLCWK. Cell proliferation was assayed by MTT assays. Apoptosis and the cell cycle phases were detected by flow cytometry. Western blotting and Q-PCR assays were used to detect the expression levels of proteins and genes related to the IL-6/STAT3 signalling pathway. A mouse model for CAC was established by treating animals with 12.5 mg/kg azoxymethane (AOM) followed by 3 cycles of 2.5% dextran sodium sulphate (DSS). The associated pathological changes were determined after haematoxylin and eosin (H&E) staining. The expression of related proteins and genes in various tissues was examined using immunofluorescence techniques. Results. FLCWK enhanced the ability of 5-FU to promote apoptosis by inhibiting the proliferation of HCT116 cells and blocking the IL-6/STAT3 pathway. FLCWK combined with 5-FU reduced the number and size of colon tumors in mice with CAC and significantly increased their survival rate. In the CAC model, FLCWK synergized with 5-FU to inhibit the phosphorylation of STAT3, preventing IL-6/STAT3 signal transduction and thus further inducing apoptosis and inhibition of colon cancer cell proliferation. Conclusion. FLCWK can inhibit the activation of STAT3 by reducing the production of IL-6, thereby increasing the occurrence of colitis-related colorectal cancer with 5-FU.

Update on the role of Angiogenesis in Diabetes associated Nephropathy

2021 ◽  
pp. 3947-3954
Author(s):  
Munish Kakkar ◽  
Shreeja Singh ◽  
Tapan Behl ◽  
Sukhbir Singh ◽  
Neelam Sharma ◽  
...  
Keyword(s):  
Renal Failure ◽  
Diabetic Nephropathy ◽  
Morphological Changes ◽  
Cell Types ◽  
Organ Damage ◽  
Lethal Complications ◽  
Multiple Cell ◽  
Original Size ◽  
Predictable Condition

Diabetic mellitus is common worldwide health problem which brings about different rigorous complications like retinopathy, nephropathy and numerous other lethal complications. Diabetic nephropathy is the major cause for blindness and renal failure in many of the developing countries. Hyperglycemia induced diabetic nephropathy gets elicited through improved development of reactive oxygen species in multiple cell types. The starting of organ damage or kidney failure shows some symptomatic effect or morphological changes as in one or both the kidneys like expansion or enlargement of kidneys from their original size and this enlargement process is known as nephromegaly. Microalbuminuria is the best possible predictable condition proceeding towards renal failure. This review briefly discussed about the diabetic nephropathy with regard to progression, angiogenic and non-angiogenic factors involved in pathogenesis and treatment of angiogenesis in diabetic nephropathy.

scholarly journals Morphological changes in rat pancreatic slices associated with inhibition of enzyme secretion by high concentrations of secretagogues.

1978 ◽  
Vol 76 (2) ◽  
pp. 467-482 ◽  
Author(s):  
N Savion ◽  
Z Selinger
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Morphological Changes ◽  
Dose Response Curve ◽  
Enzyme Secretion ◽  
High Concentration ◽  
Luminal Membrane ◽  
Morphological Studies ◽  
High Concentrations ◽  
The Right

Stimulation of enzyme secretion in rat pancreatic slices by cholinergic agonists or by cholecystokinin-pancreozymin (CCK-PZ) and its peptide analogs showed a biphasic dose response curve. The optimal concentrations eliciting an efficient rate of enzyme secretion were 1 microM for carbamylcholine or acetylcholine, and 5 nM and 20 nM for CCK-PZ octapeptide and CCK-PZ, respectively. At higher concentrations of secretagogues, however, the rate of secretion progressively declined, and almost complete inhibition was achieved at 1 mM of carbamylcholine or acetylcholine and at 0.1 microM of CCK-PZ or its octapeptide analog. Atropine displaced the dose-response curve for carbamylcholine to the right so that in the presence of 7 microM atropine a concentration of 1 mM carbamylcholine now gave an optimal rate of enzyme secretion. The ionophore A-23187 which bypasses the receptor and elicits enzyme secretion did not relieve the inhibition caused by supraoptimal concentrations of secretagogues, indicating that the inhibition occurs at the cellular rather than at the receptor level. Secretin had no effect on the inhibition of enzyme secretion by a high concentration of carbamylcholine, indicating that the inhibition was not caused by lack of water and electrolyte secretion. The energy-producing metabolism was not affected since the ATP level in the pancreatic slices was the same in the presence of either inhibitory or optimal concentrations of secretagogues. The inhibition of enzyme secretion was reversible since restoration of efficient enzyme secretion occurred after removal of carbamylcholine (1 mM) by washing, followed by addition of an optimal concentration of CCK-PZ octapeptide. Morphological studies revealed that the presence of inhibitory concentrations of secretagogues caused severe distortion of the lumen structure: disruption of the filamentous system surrounding the lumen, disappearance of microvilli, and production of distended evaginations of the luminal membrane containing cellular material. These changes eventually caused a reduction in the size of the lumen which becomes plugged with secretory material. It is suggested that these changes in the microtubular microfilamentous system could account for the inhibition of enzyme secretion.

scholarly journals Eagle-Type Methicillin Resistance: New Phenotype of High Methicillin Resistance under mec Regulator Gene Control

2001 ◽  
Vol 45 (3) ◽  
pp. 815-824 ◽  
Author(s):  
Noriko Kondo ◽  
Kyoko Kuwahara-Arai ◽  
Hiroko Kuroda-Murakami ◽  
Eiko Tateda-Suzuki ◽  
Keiichi Hiramatsu
Keyword(s):  
Gene Transcription ◽  
Genomic Library ◽  
Methicillin Resistance ◽  
Genetic Alteration ◽  
Specific Gene ◽  
High Concentration ◽  
Methicillin Resistant ◽  
Mutant Strains ◽  
Multiple Copies ◽  
High Concentrations

ABSTRACT We report a novel phenotype of methicillin resistance, designated “Eagle-type” resistance, which is characteristic in its resistance to high concentrations of methicillin (64 to 512 μg/ml) and susceptibility to low concentrations of methicillin (2 to 16 μg/ml). The type of resistance was expressed in mutant strains selected with high concentrations (e.g., 128 to 512 μg/ml) of methicillin from the pre-methicillin-resistant Staphylococcus aureus strain N315, whose mecA gene transcription is strongly repressed by the mecI gene-encoded repressor protein MecI. The Eagle-type mutant strains harbored no mutation in themecI gene or in the operator region ofmecA gene to which MecI repressor is supposed to bind. In the representative Eagle-type strain h4, repression of mecAgene transcription and penicillin-binding protein 2′ production were found to be released by exposing the cells to a high concentration (128 μg/ml) of methicillin but not to lower concentrations (1 and 8 μg/ml) of methicillin. The strain h4 expressed paradoxical susceptibility (Eagle effect) to the cytokilling activity of methicillin. Experimental deletion of mecI gene from the chromosome of h4 by mecI-specific gene substitution converted its Eagle-type resistance to homogeneously high methicillin resistance. We cloned two novel genes, designated hmrA andhmrB, from genomic library of h4, which conferred Eagle-type resistance to N315 when introduced into the cell in multiple copies. The genes were shown to confer homogeneous methicillin resistance to the heterogeneously methicillin-resistant strain LR5 when they were introduced into on multicopy plasmids. This result strongly indicated that the genetic alteration responsible for the expression of the Eagle phenotype is identical, or equivalent in its effect, to the genetic alteration underlying heterogeneous-to-homogeneous conversion of methicillin resistance in S. aureus.

Effect of verapamil on cytoplasmic distribution of granules and microfilaments in amphibian urinary bladder

1988 ◽  
Vol 46 ◽  
pp. 324-325
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Morphological Changes ◽  
Granular Cell ◽  
Cytosolic Calcium ◽  
Calcium Storage ◽  
Amphibian Urinary Bladder ◽  
Vesicular Membrane ◽  
High Concentrations ◽  
Cytoskeletal System

The amphibian urinary bladder has been used as a ‘model’ system for studies of the mechanism of action of antidiuretic hormone (ADH) in stimulating transepithelial water flow. The increase in water permeability is accompanied by morphological changes that include the stimulation of apical microvilli, mobilization of microtubules and microfilaments and vesicular membrane fusion events . It has been shown that alterations in the cytosolic calcium concentrations can inhibit ADH transmembrane water flow and induce alterations in the epithelial cell cytomorphology, including the cytoskeletal system . Recently, the subapical granules of the granular cell in the amphibian urinary bladder have been shown to contain high concentrations of calcium, and it was suggested that these cytoplasmic constituents may act as calcium storage sites for intracellular calcium homeostasis. The present study utilizes the calcium antagonist, verapamil, to examine the effect of calcium deprivation on the cytomorphological features of epithelial cells from amphibian urinary bladder, with particular emphasis on subapical granule and microfilament distribution.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

Ultrastructural Study of a differentiating human colon carcinoma cell line

1990 ◽  
Vol 48 (3) ◽  
pp. 208-209
Author(s):  
Sylvie Polak-Charcon ◽  
Mehrdad Hekmati ◽  
Yehuda Ben Shaul
Keyword(s):  
Cell Line ◽  
Morphological Changes ◽  
Secretory Granules ◽  
Human Colon ◽  
Cell Types ◽  
Culture Conditions ◽  
Morphological Evidence ◽  
Human Colon Carcinoma Cell ◽  
Colon Cell

The epithelium of normal human colon mucosa “in vivo” exhibits a gradual pattern of differentiation as undifferentiated stem cells from the base of the crypt of “lieberkuhn” rapidly divide, differentiate and migrate toward the free surface. The major differentiated cell type of the intestine observed are: absorptive cells displaying brush border, goblet cells containing mucous granules, Paneth and endocrine cells containing dense secretory granules. These different cell types are also found in the intestine of the 13-14 week old embryo.We present here morphological evidence showing that HT29, an adenocarcinoma of the human colon cell line, can differentiate into various cell types by changing the growth and culture conditions and mimic morphological changes found during development of the intestine in the human embryo.HT29 cells grown in tissue-culture dishes in DMEM and 10% FCS form at late confluence a multilayer of morphologically undifferentiated cell culture covered with irregular microvilli, and devoid of tight junctions (Figs 1-3).

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