1
|
Stratification relieves constraints from steric hindrance in the generation of compact actomyosin asters at the membrane cortex. SCIENCE ADVANCES 2020; 6:eaay6093. [PMID: 32195346 PMCID: PMC7065884 DOI: 10.1126/sciadv.aay6093] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 12/16/2019] [Indexed: 06/10/2023]
Abstract
Recent in vivo studies reveal that several membrane proteins are driven to form nanoclusters by active contractile flows arising from localized dynamic patterning of F-actin and myosin at the cortex. Since myosin-II assemble as minifilaments with tens of myosin heads, one might worry that steric considerations would obstruct the emergence of nanoclustering. Using coarse-grained, agent-based simulations that account for steric constraints, we find that the patterns exhibited by actomyosin in two dimensions, do not resemble the steady-state patterns in our in vitro reconstitution of actomyosin on a supported bilayer. We perform simulations in a thin rectangular slab, separating the layer of actin filaments from myosin-II minifilaments. This recapitulates the observed features of in vitro patterning. Using super resolution microscopy, we find evidence for such stratification in our in vitro system. Our study suggests that molecular stratification may be an important organizing feature of the cortical cytoskeleton in vivo.
Collapse
|
2
|
Applying reverse stable isotope labeling analysis by mid-infrared laser spectroscopy to monitor BDOC in recycled wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 665:1064-1072. [PMID: 30893738 DOI: 10.1016/j.scitotenv.2019.02.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/23/2019] [Accepted: 02/04/2019] [Indexed: 06/09/2023]
Abstract
Biological stability of treated wastewater is currently determined by methods such as biological oxygen demand, ATP-quantification, or flow-cytometric cell counting. However, the continuous increase in water reclamation for wastewater reuse requires new methods for quantifying degradation of biodegradable dissolved organic carbon (BDOC) ranging from very small to high concentrations of dissolved organic carbon (DOC). Furthermore, direct activity measures or absolute concentrations of BDOC are needed that produce comparable and reproducible results in all laboratories. Measuring carbon mineralization by CO2 evolution presents a suitable approach for directly measuring the microbial degradation activity. In this work, we investigated the extent of BDOC in water samples from effluent of a wastewater treatment plant and after purification by ultrafiltration over 204 days. BDOC monitoring was performed with the recently introduced reverse stable isotope labeling (RIL) analysis using mid-infrared spectroscopy for the monitoring of microbial CO2 production. Average BDOC degradation rates ranged from 0.11 to 0.32 mg L-1 d-1 for wastewater treatment plant effluent and from 0.03 to 0.22 mg L-1 d-1 after ultrafiltration. BDOC was degraded over >90 days indicating the long-term instability of the DOC. Degradation experiments over 88 days revealed first order kinetic rate constants for BDOC which corresponded to 12.7 · 10-3 d-1 for wastewater treatment plant effluent and 2.7 · 10-3 d-1 after ultrafiltration, respectively. A thorough sensitivity analysis of the RIL showed that the method is very accurate and sensitive with method detection limits down to 10 μg· L-1 of measured CO2.
Collapse
|
3
|
EHD2 is a mechanotransducer connecting caveolae dynamics with gene transcription. J Cell Biol 2018; 217:4092-4105. [PMID: 30348749 PMCID: PMC6279385 DOI: 10.1083/jcb.201801122] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 07/04/2018] [Accepted: 09/27/2018] [Indexed: 11/30/2022] Open
Abstract
Caveolae are dynamic mechanosensors. Torrino et al. show that EHD2 plays a crucial role in the adaptation to mechanical perturbations by maintaining the caveolae reservoir at the plasma membrane after changes in membrane tension and connecting caveolae mechanosensing at the plasma membrane with the regulation of gene transcription. Caveolae are small invaginated pits that function as dynamic mechanosensors to buffer tension variations at the plasma membrane. Here we show that under mechanical stress, the EHD2 ATPase is rapidly released from caveolae, SUMOylated, and translocated to the nucleus, where it regulates the transcription of several genes including those coding for caveolae constituents. We also found that EHD2 is required to maintain the caveolae reservoir at the plasma membrane during the variations of membrane tension induced by mechanical stress. Metal-replica electron microscopy of breast cancer cells lacking EHD2 revealed a complete absence of caveolae and a lack of gene regulation under mechanical stress. Expressing EHD2 was sufficient to restore both functions in these cells. Our findings therefore define EHD2 as a central player in mechanotransduction connecting the disassembly of the caveolae reservoir with the regulation of gene transcription under mechanical stress.
Collapse
|
4
|
Tailor-made ezrin actin binding domain to probe its interaction with actin in-vitro. PLoS One 2015; 10:e0123428. [PMID: 25860910 PMCID: PMC4393143 DOI: 10.1371/journal.pone.0123428] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/03/2015] [Indexed: 11/27/2022] Open
Abstract
Ezrin, a member of the ERM (Ezrin/Radixin/Moesin) protein family, is an Actin-plasma membrane linker protein mediating cellular integrity and function. In-vivo study of such interactions is a complex task due to the presence of a large number of endogenous binding partners for both Ezrin and Actin. Further, C-terminal actin binding capacity of the full length Ezrin is naturally shielded by its N-terminal, and only rendered active in the presence of Phosphatidylinositol bisphosphate (PIP2) or phosphorylation at the C-terminal threonine. Here, we demonstrate a strategy for the design, expression and purification of constructs, combining the Ezrin C-terminal actin binding domain, with functional elements such as fusion tags and fluorescence tags to facilitate purification and fluorescence microscopy based studies. For the first time, internal His tag was employed for purification of Ezrin actin binding domain based on in-silico modeling. The functionality (Ezrin-actin interaction) of these constructs was successfully demonstrated by using Total Internal Reflection Fluorescence Microscopy. This design can be extended to other members of the ERM family as well.
Collapse
|
5
|
Unexpected membrane dynamics unveiled by membrane nanotube extrusion. Biophys J 2013; 104:1248-56. [PMID: 23528084 DOI: 10.1016/j.bpj.2013.01.051] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 11/20/2012] [Accepted: 01/08/2013] [Indexed: 11/17/2022] Open
Abstract
In cell mechanics, distinguishing the respective roles of the plasma membrane and of the cytoskeleton is a challenge. The difference in the behavior of cellular and pure lipid membranes is usually attributed to the presence of the cytoskeleton as explored by membrane nanotube extrusion. Here we revisit this prevalent picture by unveiling unexpected force responses of plasma membrane spheres devoid of cytoskeleton and synthetic liposomes. We show that a tiny variation in the content of synthetic membranes does not affect their static mechanical properties, but is enough to reproduce the dynamic behavior of their cellular counterparts. This effect is attributed to an amplified intramembrane friction. Reconstituted actin cortices inside liposomes induce an additional, but not dominant, contribution to the effective membrane friction. Our work underlines the necessity of a careful consideration of the role of membrane proteins on cell membrane rheology in addition to the role of the cytoskeleton.
Collapse
|
6
|
Cells respond to mechanical stress by rapid disassembly of caveolae. Cell 2011; 144:402-13. [PMID: 21295700 DOI: 10.1016/j.cell.2010.12.031] [Citation(s) in RCA: 634] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 10/27/2010] [Accepted: 12/23/2010] [Indexed: 12/15/2022]
Abstract
The functions of caveolae, the characteristic plasma membrane invaginations, remain debated. Their abundance in cells experiencing mechanical stress led us to investigate their role in membrane-mediated mechanical response. Acute mechanical stress induced by osmotic swelling or by uniaxial stretching results in a rapid disappearance of caveolae, in a reduced caveolin/Cavin1 interaction, and in an increase of free caveolins at the plasma membrane. Tether-pulling force measurements in cells and in plasma membrane spheres demonstrate that caveola flattening and disassembly is the primary actin- and ATP-independent cell response that buffers membrane tension surges during mechanical stress. Conversely, stress release leads to complete caveola reassembly in an actin- and ATP-dependent process. The absence of a functional caveola reservoir in myotubes from muscular dystrophic patients enhanced membrane fragility under mechanical stress. Our findings support a new role for caveolae as a physiological membrane reservoir that quickly accommodates sudden and acute mechanical stresses.
Collapse
|
7
|
Mehr Einblick gewinnen in Bioreaktoren durch CFD-Simulation. CHEM-ING-TECH 2005. [DOI: 10.1002/cite.200590363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
8
|
In-situ-fluorescence-probes: a useful tool for non-invasive bioprocess monitoring. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2002; 74:21-38. [PMID: 11991181 DOI: 10.1007/3-540-45736-4_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Optical sensors appear to be very promising for different applications in modern biotechnology. They offer the possibility to interface all the well known optical analysis techniques to bioprocesses via fiber optical cables. Thus, high sophisticated and sensitive optical analysis techniques can be coupled to a bioprocess via these light signal transporting fibers. A wide variety of sensor types for application in biotechnology has been described. Normally these sensors are non-invasive and the response times are nearly instantaneous. In particular, the use of glass fiber technology makes these sensors small, robust and reduces their costs.
Collapse
|
9
|
Abstract
In dialysis fermentations inhibiting metabolites can be removed from cell suspensions resulting in a prolonged exponential growth phase and higher production yields. Because of successful high cell density cultivations of Escherichia coli in a laboratory dialysis reactor, a scale-up of the process was investigated. To provide sufficient membrane area for dialysis in a technical scale fermenter, an external membrane module was used, that was also applied for oxygen supply to the culture in the external loop. Cultivations with recombinant E. coli K12, with and without induction, in 2- and 300-l reactors were carried out using external modules. Cell densities exceeding 190 g l(-1), previously obtained in laboratory dialysis fermentation, were also produced with external dialysis modules. Protein concentration in a 300-l reactor was increased to the 3.8-fold of industrial fed-batch-fermentations.
Collapse
|
10
|
Abstract
The aim of the study was, to evaluate the metabolic effect of HAY's diet on protein turnover, fat oxidation, respiratory quotient, body fat and weight loss. Twelve healthy adults received an individually regular diet and thereafter a corresponding isocaloric and isonitrogenous 10-day HAY-diet. Protein turnover and 13C-fat oxidation were investigated after administration of [15N]glycine and an [U-13C]algae lipid mixture. The 15N and 13C enrichment in urine and breath were measured by isotope ratio mass spectrometry. The respiratory quotient was measured by indirect calorimetry. Body fat, total body water and lean body mass were estimated by bio-electric impedance analysis. HAY's diet led to a significantly higher 13C-fat oxidation (15.4 vs. 22.0% P < 0.01), corresponding to a lower respiratory quotient (0.88 vs. 0.81; P < 0.01), whereas the protein turnover remained constant in both diets (3.06 vs. 3.05 g/kg/day). HAY's diet did not reduce total body water, lean body mass, body fat and body weight (72.2 vs. 71.4 kg).
Collapse
|
11
|
67. System zur rechnergestützten Aufstellungsplanung. CHEM-ING-TECH 1996. [DOI: 10.1002/cite.330680969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
12
|
171. Erfahrungen mit dem Einsatz eines Rohrbrückenbelegungssystems. CHEM-ING-TECH 1996. [DOI: 10.1002/cite.3306809173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
13
|
14. Beiträge der Hochschulforschung zur rechnergestützten Aufstellungsplanung. CHEM-ING-TECH 1994. [DOI: 10.1002/cite.330660915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
14
|
Abstract
Few studies have been carried out to evaluate the role of hepatitis A virus (HAV) as an occupational hazard. Our analysis of data on occupational diseases in Germany showed that hepatitis A ranks as third among infectious occupational diseases. Morbidity based on the frequency of compensation (15.2%) was in the same range as that observed for hepatitis B (19.7%). In another study, data were collected on anti-HAV prevalence among 2293 hospital workers in southwest Germany. Anti-HAV prevalence of hospital staff responsible for patient care and that of the general population were comparable, while food-handlers under the age of 30 years had a higher degree of anti-HAV prevalence. When an evaluation of anti-HAV prevalence data was carried out on persons younger than 30 years who comprised subsets of the medical staff, the relative risk was: charwomen 4.2, food-handlers 2.49, and paediatric nurses 1.84, showing that they had higher prevalence rates than nurses 1.25, physicians 1.09 and laboratory assistants 0.93. Vaccinations for the prevention of hepatitis A should therefore reach individuals that have an increased occupational risk: food-handlers, health care workers in infectious diseases and paediatrics, medical staff in laboratories handling stool samples, medical charwomen and, according to previously published work, staff of day care centres and sewerage workers.
Collapse
|
15
|
|
16
|
[Results of the surgical treatment of intervertebral disk displacement--a collective study]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1988; 35:143-7. [PMID: 3408465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
17
|
[Quantitative changes in the masticatory muscles after unilateral ligature of the common carotid artery]. DEUTSCHE ZEITSCHRIFT FUR MUND-, KIEFER- UND GESICHTS-CHIRURGIE 1988; 12:7-10. [PMID: 3163955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
18
|
[Arthrosis models of the temporomandibular joint]. PHILLIP JOURNAL FUR RESTAURATIVE ZAHNMEDIZIN 1987; 4:98-9. [PMID: 3037605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
19
|
[Mechanics of bone growth and formation]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1986; 33:90-5. [PMID: 3707503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
20
|
[Exploring the origin of joint sounds]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1979; 26:419-27. [PMID: 539981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
21
|
[Hydrolytic stability of various 1,3-dioxolane, 1,3-oxathiolane and 1,3-dithiolane derivatives]. DIE PHARMAZIE 1975; 30:170-1. [PMID: 239408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
22
|
[Blood level courses, thin layer chromatographic separation and metabolism of 1,3-dioxolanes and 1,3-oxathiolanes in the rat]. DIE PHARMAZIE 1975; 30:172-4. [PMID: 1153472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
23
|
[Our experiences with conservative treatment of hip dislocation]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1973; 20:526-33. [PMID: 4770218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
24
|
[Ossification in brachydactyly]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1971; 18:271-80. [PMID: 5000149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
25
|
[Observations after 300 lumbar intervertebral disk prolapse operations]. DAS DEUTSCHE GESUNDHEITSWESEN 1971; 26:831-6. [PMID: 5581074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
26
|
[Problems of tuberculous coxitis]. DAS DEUTSCHE GESUNDHEITSWESEN 1970; 25:2212-7. [PMID: 5487507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
27
|
[Differential diagnostic considerations concerning osteoarticular diseases in the front part of the foot]. ZEITSCHRIFT FUR ARZTLICHE FORTBILDUNG 1970; 64:1145-50. [PMID: 4396201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
28
|
[Postoperative complications in the treatment of coxarthrosis]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1970; 17:136-9. [PMID: 5516787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
29
|
[Postoperative complications in the treatment of coxarthrosis]. Zentralbl Chir 1970; 95:137-45. [PMID: 5515920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
30
|
[Course of acute and chronic nonspecific arthritis in the x-ray picture]. ZEITSCHRIFT FUR ARZTLICHE FORTBILDUNG 1969; 63:1182-5. [PMID: 5381746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
31
|
[Ossifications of the metatarsus and toes and their relations to juvenile metatarsal diseases]. ZEITSCHRIFT FUR ORTHOPADIE UND IHRE GRENZGEBIETE 1968; 104:333-51. [PMID: 4233340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
32
|
[Various observations on juvenile bone cysts]. ZEITSCHRIFT FUR ORTHOPADIE UND IHRE GRENZGEBIETE 1967; 103:92-9. [PMID: 4232510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
33
|
[Cystic bone processes and their therapy]. BEITRAGE ZUR ORTHOPADIE UND TRAUMATOLOGIE 1966; 13:794-6. [PMID: 4861982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|