Mechanics of Microtubule Buckling Supported by Cytoplasm

2008 ◽  
Vol 75 (6) ◽  
Author(s):  
Hanqing Jiang ◽  
Jiaping Zhang
Keyword(s):  
Evolution Equations ◽  
Compressive Force ◽  
Cylindrical Tube ◽  
Long Wavelength ◽  
Euler Buckling ◽  
In Vivo Experiments ◽  
Critical Wavelength ◽  
A Cell

The cytoskeleton provides the mechanical scaffold and maintains the integrity of cells. It is usually believed that one type of cytoskeleton biopolymer, microtubules, bears compressive force. In vitro experiments found that isolated microtubules may form an Euler buckling pattern with a long-wavelength for very small compressive force. This, however, does not agree with in vivo experiments where microtubules buckle with a short-wavelength. In order to understand the structural role of microtubules in vivo, we developed mechanics models that study microtubule buckling supported by cytoplasm. The microtubule is modeled as a linearly elastic cylindrical tube while the cytoplasm is characterized by different types of materials, namely, viscous, elastic, or viscoelastic. The dynamic evolution equations, the fastest growth rate, the critical wavelength, and compressive force, as well as equilibrium buckling configurations are obtained. The ability for a cell to sustain compressive force does not solely rely on microtubules but is also supported by the elasticity of cytoplasm. With the support of the cytoplasm, an individual microtubule can sustain a compressive force on the order of 100pN. The relatively stiff microtubules and compliant cytoplasm are combined to provide a scaffold for compressive force.

scholarly journals LysGH15 Effectively Control Murine Mastitis Caused by Staphylococcus aureus

2020 ◽  
Vol 40 (04) ◽  
pp. 519-522
Author(s):  
Yalu Ji
Keyword(s):  
Staphylococcus Aureus ◽  
Breast Tissue ◽  
Bovine Mastitis ◽  
Gram Positive Bacteria ◽  
In Vivo Experiments ◽  
Tnf Α ◽  
A Cell ◽  
Phage Lysin

Bovine mastitis is an inflammatory response mainly caused by Staphylococcus aureus. Lysin is a cell wall hydrolase encoded and synthesized by a bacteriophage, which can kill specific Gram-positive bacteria. In this study, phage lysin “LysGH15” is used to treat the mice mastitis caused by S. aureus. The purified lysGH15 showed strong bactericidal activity in vitro. When treated with 25μg/mL of the LysGH15, the bacterial counts of S. aureus dropped approximately 5 log units within 10 min. In the in vivo experiments, the administration of LysGH15 significantly (P<0.05) reduced the colonies of S. aureus and alleviated damage to the breast tissue. Also, the levels of IL-6 and TNF-α in breast tissue were significantly decreased. It indicates that the LysGH15 can effectively treat the murine mastitis caused by S. aureus. This study demonstrated the potential of LysGH15 as an alternative to antibiotics for treating bovine mastitis caused by S. aureus

BENEFIT OF A CELL PENETRABLE SH-COMPOUND FOR PLATELET PREPARATION AND STORAGE

1987 ◽  
Author(s):  
I Bergmann ◽  
T Siepmann ◽  
P KLeinert ◽  
G P Pescarmona ◽  
W Lôsche ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Room Temperature ◽  
Human Platelets ◽  
In Vivo Experiments ◽  
Morphological Index ◽  
A Cell ◽  
Cytoprotective Agent ◽  
And Storage

The SH-containing drug 2-mercaptopropionylglycine (2-MPG) which inhibits platelet aggregation in a reversible manner was used as a cytoprotective agent in some experiments on storage of human platelets for transfusion.In vitro-experimentss Blood of 6 healthy volunteers was collected in ACD (control) and in ACD containing 2-MPG. Platelets were stored as PRP at room temperature. Daily, samples of stored platelets were spun down, resuspended in fresh homologous plasma adjusted to pH 7.4, and rewarmed to 37° C for 1 hour, thus simulating in vitro the in vivo-conditions after platelet transfusion. Among various platelet function tests the morphological index according to KUNICKI et al. (Transfusion 15, 414, 1975) indicated a significantly higher integrity of the platelets prepared and stored in presence of 2-MPG compared to controls.In vivo-experiments: Platelets of 2 healthy volunteers were labelles with 111-In after storage of 2 days and retransfused. When platelets had been prepared and stored in presence of 2-MPG the recovery was increased and the survival prolonged compared to the controls.The results indicate that 2-MPG may have benefit for the preparation and storage of platelets for transfusion.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

ANTITUMOR EFFECT OF COLLOIDAL SILVER BISILICATE IN EXPERIMENTAL IN VITRO AND IN VIVO STUDIES

2019 ◽  
Vol 65 (5) ◽  
pp. 760-765
Author(s):  
Margarita Tyndyk ◽  
Irina Popovich ◽  
A. Malek ◽  
R. Samsonov ◽  
N. Germanov ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Human Tumor ◽  
Significant Inhibition ◽  
In Vivo Studies ◽  
Ehrlich Carcinoma ◽  
In Vivo Experiments

The paper presents the results of the research on the antitumor activity of a new drug - atomic clusters of silver (ACS), the colloidal solution of nanostructured silver bisilicate Ag6Si2O7 with particles size of 1-2 nm in deionized water. In vitro studies to evaluate the effect of various ACS concentrations in human tumor cells cultures (breast cancer, colon carcinoma and prostate cancer) were conducted. The highest antitumor activity of ACS was observed in dilutions from 2.7 mg/l to 5.1 mg/l, resulting in the death of tumor cells in all studied cell cultures. In vivo experiments on transplanted Ehrlich carcinoma model in mice consuming 0.75 mg/kg ACS with drinking water revealed significant inhibition of tumor growth since the 14th day of experiment (maximally by 52% on the 28th day, p < 0.05) in comparison with control. Subcutaneous injections of 2.5 mg/kg ACS inhibited Ehrlich's tumor growth on the 7th and 10th days of the experiment (p < 0.05) as compared to control.

Analysis of the Dynamics of the Electric Capacitance of a Cell Monolayer at the Late Stages of Caco-2 cell Differentiation

2019 ◽  
Vol 35 (6) ◽  
pp. 87-90
Author(s):  
S.V. Nikulin ◽  
V.A. Petrov ◽  
D.A. Sakharov
Keyword(s):  
Impedance Spectroscopy ◽  
Cell Monolayer ◽  
Microfluidic Chips ◽  
Russian Science ◽  
Electric Capacitance ◽  
A Cell ◽  
Static Conditions ◽  
Late Stages

The real-time monitoring of electric capacitance (impedance spectroscopy) allowed obtaining evidence that structures which look like intestinal villi can be formed during the cultivation under static conditions as well as during the cultivation in microfluidic chips. It was shown in this work via transcriptome analysis that the Hh signaling pathway is involved in the formation of villus-like structures in vitro, which was previously shown for their formation in vivo. impedance spectroscopy, intestine, villi, electric capacitance, Hh The study was funded by the Russian Science Foundation (Project 16-19-10597).

scholarly journals Plant-Derived Extracellular Vesicles: Current Findings,Challenges, and Future Applications

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 411
Author(s):  
Nader Kameli ◽  
Anya Dragojlovic-Kerkache ◽  
Paul Savelkoul ◽  
Frank R. Stassen
Keyword(s):  
Human Health ◽  
Extracellular Vesicles ◽  
Preliminary Results ◽  
In Vivo Experiments ◽  
Health And Disease ◽  
Conducting Research ◽  
Protocol Standardization ◽  
Insight Into

In recent years, plant-derived extracellular vesicles (PDEVs) have gained the interest of many experts in fields such as microbiology and immunology, and research in this field has exponentially increased. These nano-sized particles have provided researchers with a number of interesting findings, making their application in human health and disease very promising. Both in vitro and in vivo experiments have shown that PDEVs can exhibit a multitude of effects, suggesting that these vesicles may have many potential future applications, including therapeutics and nano-delivery of compounds. While the preliminary results are promising, there are still some challenges to face, such as a lack of protocol standardization, as well as knowledge gaps that need to be filled. This review aims to discuss various aspects of PDEV knowledge, including their preliminary findings, challenges, and future uses, giving insight into the complexity of conducting research in this field.

scholarly journals Osteoprotective Effects of Loganic Acid on Osteoblastic and Osteoclastic Cells and Osteoporosis-Induced Mice

2020 ◽  
Vol 22 (1) ◽  
pp. 233
Author(s):  
Eunkuk Park ◽  
Chang Gun Lee ◽  
Eunguk Lim ◽  
Seokjin Hwang ◽  
Seung Hee Yun ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Osteoblastic Differentiation ◽  
Common Disease ◽  
Root Extract ◽  
Mouse Bone Marrow ◽  
Mineral Density ◽  
Bone Mineral Density Loss ◽  
In Vivo Experiments

Osteoporosis is a common disease caused by an imbalance of processes between bone resorption by osteoclasts and bone formation by osteoblasts in postmenopausal women. The roots of Gentiana lutea L. (GL) are reported to have beneficial effects on various human diseases related to liver functions and gastrointestinal motility, as well as on arthritis. Here, we fractionated and isolated bioactive constituent(s) responsible for anti-osteoporotic effects of GL root extract. A single phytochemical compound, loganic acid, was identified as a candidate osteoprotective agent. Its anti-osteoporotic effects were examined in vitro and in vivo. Treatment with loganic acid significantly increased osteoblastic differentiation in preosteoblast MC3T3-E1 cells by promoting alkaline phosphatase activity and increasing mRNA expression levels of bone metabolic markers such as Alpl, Bglap, and Sp7. However, loganic acid inhibited osteoclast differentiation of primary-cultured monocytes derived from mouse bone marrow. For in vivo experiments, the effect of loganic acid on ovariectomized (OVX) mice was examined for 12 weeks. Loganic acid prevented OVX-induced bone mineral density loss and improved bone structural properties in osteoporotic model mice. These results suggest that loganic acid may be a potential therapeutic candidate for treatment of osteoporosis.

scholarly journals Regorafenib-Attenuated, Bleomycin-Induced Pulmonary Fibrosis by Inhibiting the TGF-β1 Signaling Pathway

2021 ◽  
Vol 22 (4) ◽  
pp. 1985
Author(s):  
Xiaohe Li ◽  
Ling Ma ◽  
Kai Huang ◽  
Yuli Wei ◽  
Shida Long ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Kinase Inhibitor ◽  
In Vivo Experiments ◽  
Age Related ◽  
And Migration ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a fatal and age-related pulmonary disease. Nintedanib is a receptor tyrosine kinase inhibitor, and one of the only two listed drugs against IPF. Regorafenib is a novel, orally active, multi-kinase inhibitor that has similar targets to nintedanib and is applied to treat colorectal cancer and gastrointestinal stromal tumors in patients. In this study, we first identified that regorafenib could alleviate bleomycin-induced pulmonary fibrosis in mice. The in vivo experiments indicated that regorafenib suppresses collagen accumulation and myofibroblast activation. Further in vitro mechanism studies showed that regorafenib inhibits the activation and migration of myofibroblasts and extracellular matrix production, mainly through suppressing the transforming growth factor (TGF)-β1/Smad and non-Smad signaling pathways. In vitro studies have also indicated that regorafenib could augment autophagy in myofibroblasts by suppressing TGF-β1/mTOR (mechanistic target of rapamycin) signaling, and could promote apoptosis in myofibroblasts. In conclusion, regorafenib attenuates bleomycin-induced pulmonary fibrosis by suppressing the TGF-β1 signaling pathway.

scholarly journals Bioactive Compounds from Herbal Medicine Targeting Multiple Myeloma

2021 ◽  
Vol 11 (10) ◽  
pp. 4451
Author(s):  
Coralia Cotoraci ◽  
Alina Ciceu ◽  
Alciona Sasu ◽  
Eftimie Miutescu ◽  
Anca Hermenean
Keyword(s):  
Multiple Myeloma ◽  
Survival Rate ◽  
Plasma Cells ◽  
Inhibition Of Proliferation ◽  
In Vivo Experiments ◽  
Clonal Proliferation ◽  
Hematological Cancers ◽  
Monoclonal Proteins

Multiple myeloma (MM) is one of the most widespread hematological cancers. It is characterized by a clonal proliferation of malignant plasma cells in the bone marrow and by the overproduction of monoclonal proteins. In recent years, the survival rate of patients with multiple myeloma has increased significantly due to the use of transplanted stem cells and of the new therapeutic agents that have significantly increased the survival rate, but it still cannot be completely cured and therefore the development of new therapeutic products is needed. Moreover, many patients have various side effects and face the development of drug resistance to current therapies. The purpose of this review is to highlight the bioactive active compounds (flavonoids) and herbal extracts which target dysregulated signaling pathway in MM, assessed by in vitro and in vivo experiments or clinical studies, in order to explore their healing potential targeting multiple myeloma. Mechanistically, they demonstrated the ability to promote cell cycle blockage and apoptosis or autophagy in cancer cells, as well as inhibition of proliferation/migration/tumor progression, inhibition of angiogenesis in the tumor vascular network. Current research provides valuable new information about the ability of flavonoids to enhance the apoptotic effects of antineoplastic drugs, thus providing viable therapeutic options based on combining conventional and non-conventional therapies in MM therapeutic protocols.

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