scholarly journals Interplay between MPIase, YidC, and PMF during Sec-independent insertion of membrane proteins

2021 ◽  
Vol 5 (1) ◽  
pp. e202101162
Author(s):  
Yuta Endo ◽  
Yuko Shimizu ◽  
Hanako Nishikawa ◽  
Katsuhiro Sawasato ◽  
Ken-ichi Nishiyama
Keyword(s):  
Membrane Proteins ◽  
Molecular Basis ◽  
Terminal Region ◽  
Integral Membrane Proteins ◽  
The Other ◽  
Other Hand ◽  
Model Protein

Integral membrane proteins with the N-out topology are inserted into membranes usually in YidC- and PMF-dependent manners. The molecular basis of the various dependencies on insertion factors is not fully understood. A model protein, Pf3-Lep, is inserted independently of both YidC and PMF, whereas the V15D mutant requires both YidC and PMF in vivo. We analyzed the mechanisms that determine the insertion factor dependency in vitro. Glycolipid MPIase was required for insertion of both proteins because MPIase depletion caused a significant defect in insertion. On the other hand, YidC depletion and PMF dissipation had no effects on Pf3-Lep insertion, whereas V15D insertion was reduced. We reconstituted (proteo)liposomes containing MPIase, YidC, and/or F0F1-ATPase. MPIase was essential for insertion of both proteins. YidC and PMF stimulated Pf3-Lep insertion as the synthesis level increased. V15D insertion was stimulated by both YidC and PMF irrespective of the synthesis level. These results indicate that charges in the N-terminal region and the synthesis level are the determinants of YidC and PMF dependencies with the interplay between MPIase, YidC, and PMF.

Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

1987 ◽  
Vol 52 (9) ◽  
pp. 2317-2325 ◽  
Author(s):  
Jan Hlaváček ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Walter Y. Chan ◽  
Victor J. Hruby
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
The Other ◽  
Amino Acid Residues ◽  
Phase Synthesis ◽  
Other Hand ◽  
Fragment Condensation

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.

In vitro insulin-mimetic activity and in vivo metallokinetic feature of oxovanadium(IV)porphyrin complexes in healthy rats

2012 ◽  
Vol 16 (01) ◽  
pp. 114-121 ◽  
Author(s):  
Tapan K. Saha ◽  
Yutaka Yoshikawa ◽  
Hirouki Yasui ◽  
Hiromu Sakurai
Keyword(s):  
The Other ◽  
Insulin Mimetic ◽  
Other Hand ◽  
Better Than

We prepared [meso-tetrakis(4-carboxylatophenyl)porphyrinato]oxovanadium(IV) tetrasodium, ([VO(tcpp)]Na4), and investigated its in vitro insulin-mimetic activity and in vivo metallokinetic feature in healthy rats. The results were compared with those of previously proposed insulin-mimetic oxovanadium(IV)porphyrin complexes and oxovanadium(IV) sulphate. The in vitro insulin-mimetic activity and bioavailability of [VO(tcpp)]Na4 were considerably better than those of [meso-tetrakis (1-methylpyridinium-4-yl)porphyrinato]oxovanadium(IV)(4+) tetraperchlorate ([VO(tmpyp)](ClO4)4) and oxovanadium(IV) sulphate. On the other hand, [VO(tcpp)]Na4 and [meso-tetrakis(4-sulfonatophenyl) porphyrinato]oxidovanadate(IV)(4-)([VO(tpps)]) showed very similar in vitro insulin-mimetic activity and in vivo metallokinetic feature in healthy rats. In particular, the order of in vitro insulin-mimetic activity of the complexes was determined to be: [VO(tcpp)]Na4 ≈ [VO(tpps)] > ([VO(tmpyp)](ClO4)4 > oxovanadium(IV) sulphate.

scholarly journals In vitro Multiplication of Iraca palm (Carludovica palmata Ruíz & Pavón)

2020 ◽  
Vol 73 (1) ◽  
pp. 9039-9046
Author(s):  
Rodrigo Alberto Hoyos Sanchez ◽  
Diego Chicaíza Finley ◽  
Juan Carlos Zambrano Arteaga
Keyword(s):  
Root Formation ◽  
The Other ◽  
Naphthaleneacetic Acid ◽  
Multiplication Rate ◽  
In Vitro Multiplication ◽  
Commercial Interest ◽  
Other Hand ◽  
Number Of Shoots

Carludovica palmata Ruíz & Pavón is a plant that belongs to the Cyclanthaceae family. Its commercial interest is related to the production of fibers for the manufacture of handicrafts, mainly the Panama hat, so it is important to study its propagation. This investigation aimed to determine the effect of 6-benzylaminopurine (BAP) in the formation of new shoots and 1-naphthaleneacetic acid (NAA) in the formation of roots, as well as the adaptation in greenhouse conditions of Carludovica palmata Ruíz & Pavón. In order to find the optimal multiplication rate, 0.5 cm length explants were planted in glass jars with 15 mL of semisolid MS with different concentrations of BAP and cultured under in vitro conditions for 90 days. The multiplication parameters in this stage were number of shoots per explant (NSE), length of shoots (LS), and length of roots (LR) as multiplication parameters. In a similar procedure, the number of roots per explant (NRE), length of roots (LR), and length of plantlets (LP) was determined using different concentrations of NAA. Finally, different substrates were evaluated for the adaptation of plantlets of C. palmata produced in vitro, under greenhouse conditions for 80 days. The highest multiplication rate (17±3 shoots per explant) was obtained with 2.0 mg L-1 of BAP. Root formation occurred efficiently in all treatments, without significant statistical differences between them. On the other hand, the use of substrate soil-t15 was the best treatment for the growth of C. palmata under greenhouse conditions. From the results obtained, it is concluded that C. palmata can be efficiently multiplied under in vitro conditions and did not present problems during the in vivo rooting process.

An improved polarized rat hepatoma hybrid cell line. Generation and comparison with its hepatoma relatives and hepatocytes in vivo

1994 ◽  
Vol 107 (4) ◽  
pp. 813-825 ◽  
Author(s):  
M.R. Shanks ◽  
D. Cassio ◽  
O. Lecoq ◽  
A.L. Hubbard
Keyword(s):  
Plasma Membrane ◽  
B Cells ◽  
Membrane Proteins ◽  
Cell Line ◽  
Hybrid Cell ◽  
The Other ◽  
Hepatocyte Polarity ◽  
Rat Hepatoma

Studies of hepatocyte polarity, an important property of liver epithelial cells, have been hampered by the lack of valid in vitro models. We report here that a new polarized hepatoma-derived hybrid cell line, called WIF-B, has improved characteristics to those of its parent, WIF12-1. This latter line originated from the fusion of non-polarized rat hepatoma Fao cells with human fibroblasts (WI-38) and selection for a polarized phenotype. We generated the WIF-B line by growing WIF12-1 cells as unattached aggregates for three weeks and selecting for survivors. Karyotype analysis showed a broad chromosome pattern in the initial WIF-B population, but this pattern stabilized after a few passages. The growth and phenotypic properties of these cells were quite different from those of their polarized WIF12-1 parent. WIF-B cells attained a 4-fold higher maximal density in monolayer culture, survived at this density for > 5 days rather than 1 day, and exhibited two to three times more apical structures during this period (80 to 95%). We compared several parameters of liver differentiation in the WIF-B cells with those of a related hybrid clone, WIF12-E, which is extinguished for most liver-specific functions, and with the common hepatoma parent, Fao. By immunoblot analysis, the levels of expression of eight plasma membrane proteins were higher in the WIF-B cells than in either of the other two cell lines and ranged from 10 to 200% of those in vivo. Two plasma membrane proteins were not detected in WIF12-E cells. By immunofluorescence, the apical membrane proteins in WIF-B displayed different cellular localizations than in either of the other two cell lines. In WIF-B cells, apical proteins were confined to a plasma membrane region that we have identified as the apical domain by several criteria (Ihrke, G., Neufeld, E.D., Meads, T., Shanks, M.R., Cassio, D., Laurent, M., Schroer, T.A., Pagano, R. E. and Hubbard, A. L. J. Cell Biol., 123, 1761–1765). The same molecules were distributed over the entire plasma membrane of Fao and WIF12-E cells and also (for Fao cells) in intracellular punctate structures that did not colocalize with the majority of structures containing a secretory protein, albumin. Our results indicate that the WIF-B cells are more highly differentiated than any of their ancestors (Fao or WIF12-1 cells) and thus, are promising candidates for in vitro studies of hepatocyte polarity.

CORTICOID PRODUCTION IN VITRO AS A TEST OF ADRENOCORTICAL FUNCTION IN RATS

1960 ◽  
Vol XXXIII (I) ◽  
pp. 59-66 ◽  
Author(s):  
J. van der Vies
Keyword(s):  
Adrenal Cortex ◽  
Adrenal Function ◽  
The Other ◽  
Adrenocortical Function ◽  
Experimental Conditions ◽  
Adrenal System ◽  
Other Hand ◽  
Stimulation Of

ABSTRACT Adrenal function in rats under various experimental conditions was studied by incubating the adrenals in vitro and determining the corticosteroid output during one hour. This in vitro corticoid production was reduced after hypophysectomy, hypothalamus-lesioning and treatment with hydrocortisone or with Nembutal and morphine. On the other hand, an increased production was observed following stimulation of the pituitary-adrenal system by exogenous histamine or corticotrophin. From these experiments it is concluded that the corticoid production in vitro reflects the activity of the adrenal cortex in vivo and hence can be used for the study of the latter function.

scholarly journals Plasmalemmal proteins of cultured vascular endothelial cells exhibit apical-basal polarity: analysis by surface-selective iodination.

1986 ◽  
Vol 103 (6) ◽  
pp. 2389-2402 ◽  
Author(s):  
W A Muller ◽  
M A Gimbrone
Keyword(s):  
Endothelial Cells ◽  
Membrane Proteins ◽  
Umbilical Vein ◽  
Integral Membrane Proteins ◽  
Cellular Polarity ◽  
Differential Distribution ◽  
Endothelial Monolayers ◽  
Apical Side

Vascular endothelium in vivo appears to function as a polarized epithelium. To determine whether cellular polarity exists at the level of the plasma membrane, we have examined cultured endothelial monolayers for evidence of differential distribution of externally disposed plasmalemmal proteins at apical and basal cell surfaces. Lactoperoxidase beads were used to selectively label the apical surfaces of confluent endothelial monolayers, the total surfaces of nonenzymatically resuspended cells, and the basal surfaces of monolayers inverted on poly-L-lysine-coated coverslips, while maintaining greater than 98% viability in all samples. Comparison of the SDS PAGE radioiodination patterns obtained for each surface revealed a number of specific bands markedly enriched on either apical or basal surface. This polarized distribution involved membrane-associated as well as integral membrane proteins and was observed in several strains of bovine aortic endothelial cells, as well as in both primary and passaged human umbilical vein endothelial cells. In contrast, two morphologically nonpolarized cell types, bovine aortic smooth muscle and mouse peritoneal macrophages, did not display differential localization of integral membrane proteins. Polarized distribution of integral membrane proteins was established before the formation of a confluent monolayer. When inverted (basal-side-up) monolayers were returned to culture, the apical-side-up pattern was reexpressed within a few days. These results demonstrate that cell surface-selective expression of plasmalemmal proteins is an intrinsic property of viable endothelial cells in vitro. This apical/basal asymmetry of membrane structure may provide a basis for polarized endothelial functions in vivo.

Persisting mild hypothermia suppresses hypoxia-inducible factor-1α protein synthesis and hypoxia-inducible factor-1-mediated gene expression

2010 ◽  
Vol 298 (3) ◽  
pp. R661-R671 ◽  
Author(s):  
Tomoharu Tanaka ◽  
Takuhiko Wakamatsu ◽  
Hiroki Daijo ◽  
Seiko Oda ◽  
Shinichi Kai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Low Temperature ◽  
Hypoxia Inducible Factor ◽  
The Body ◽  
The Other ◽  
Adaptation To Hypoxia ◽  
Hypoxia Inducible Factor 1 ◽  
Other Hand

The transcription factor hypoxia-inducible factor-1 (HIF-1) plays an essential role in regulating gene expression in response to hypoxia-ischemia. Ischemia causes the tissue not only to be hypoxic but also to be hypothermic because of the hypoperfusion under certain circumstances. On the other hand, the induced hypothermia is one of the most common therapeutic modalities to extend tolerance to hypoxia. Although hypoxia elicits a variety of cellular and systemic responses at different organizational levels in the body, little is known about how hypoxia-induced responses are affected by low temperature. We examined the influence of mild hypothermic conditions (28–32°C) on HIF-1 in both in vitro and in vivo settings. In vitro experiments adopting cultured cells elucidated that hypoxia-induced HIF-1 activation was resistant to 4-h exposure to the low temperature. In contrast, exposure to the low temperature as long as 24 h suppressed HIF-1 activation and the subsequent upregulation of HIF-1 target genes such as VEGF or GLUT-1. HIF-1α protein stability in the cell was not affected by hypothermic treatment. Furthermore, intracellular ATP content was reduced under 1% O2 conditions but was not largely affected by hypothermic treatment. The evidence indicates that reduction of oxygen consumption is not largely involved in suppression of HIF-1. In addition, we demonstrated that HIF-1 DNA-binding activity and HIF-1-dependent gene expressions induced under 10% O2 atmosphere in mouse brain were not influenced by treatment under 3-h hypothermic temperature but were inhibited under 5-h treatment. On the other hand, we indicated that warming ischemic legs of mice for 24 h preserved HIF-1 activity. In this report we describe for the first time that persisting low temperature significantly reduced HIF-1α neosynthesis under hypoxic conditions, leading to a decrease in gene expression for adaptation to hypoxia in both in vitro and in vivo settings.

scholarly journals Lamins in disease: why do ubiquitously expressed nuclear envelope proteins give rise to tissue-specific disease phenotypes?

2001 ◽  
Vol 114 (1) ◽  
pp. 9-19 ◽  
Author(s):  
C.J. Hutchison ◽  
M. Alvarez-Reyes ◽  
O.A. Vaughan
Keyword(s):  
Membrane Proteins ◽  
Nuclear Envelope ◽  
Dna Sequences ◽  
Genetic Disorders ◽  
Integral Membrane Proteins ◽  
Partial Lipodystrophy ◽  
Nuclear Lamins ◽  
Disease Phenotypes

The nuclear lamina is a filamentous structure composed of lamins that supports the inner nuclear membrane. Several integral membrane proteins including emerin, LBR, LAP1 and LAP2 bind to nuclear lamins in vitro and can influence lamin function and dynamics in vivo. Results from various studies suggest that lamins function in DNA replication and nuclear envelope assembly and determine the size and shape of the nuclear envelope. In addition, lamins also bind chromatin and certain DNA sequences, and might influence chromosome position. Recent evidence has revealed that mutations in A-type lamins give rise to a range of rare, but dominant, genetic disorders, including Emery-Dreifuss muscular dystrophy, dilated cardiomyopathy with conduction-system disease and Dunnigan-type familial partial lipodystrophy. An examination of how lamins A/C, emerin and other integral membrane proteins interact at the INM provides the basis for a novel model for how mutations that promote disease phenotypes are likely to influence these interactions and therefore cause cellular pathology through a combination of weakness of the lamina or altered gene expression.

Heart Rot of Jack Pine in Ontario. IV. Heartwood-inhabiting Fungi, Their Entry and Interactions within Living Trees

1975 ◽  
Vol 5 (4) ◽  
pp. 706-721 ◽  
Author(s):  
J. T. Basham
Keyword(s):  
Jack Pine ◽  
The Other ◽  
Natural Occurrence ◽  
Living Tree ◽  
Other Hand

The five most common stem-inhabiting fungi of jack pine (Pinusbanksiana Lamb.) in Ontario were inoculated into the stems of living trees that were roughly 40 years old. Their natural occurrence in branch stubs and at various heights in the stems of these trees was also studied. From these results, and from those that were obtained from older trees in earlier studies, conclusions which concern the occurrence, importance, and apparent avenues of entry of these fungi are presented. Some of the trees were inoculated with one of the Ascomycetes, which was followed 1 year later by one of the Basidiomycetes. The interactions of the fungi in vivo did not always correspond with those observed in vitro; however, they do explain many of the observed relationships between the occurrence of these fungi in living jack pine and other factors. Fomespini (Brot. ex Fr.) Karst., the Basidiomycete that is responsible for most of the trunk rot of jack pine in Ontario, was not affected in living tree stems by the presence of the Ascomycetes that frequently colonize this tissue. On the other hand, Peniophorapseudo-pini Weres. and Gibson, the Basidiomycete that is responsible for about one quarter of the red trunk stain in this species, was almost completely inhibited in living trees by the presence of Ascocorynesarcoides (Jacq. ex Gray) Groves and Wilson, which would explain many of the unusual patterns of occurrence of P. pseudo-pini in living jack pine.

scholarly journals In vitro assays misrepresent in vivo lineage potentials of murine lymphoid progenitors

Blood ◽  
2011 ◽  
Vol 117 (9) ◽  
pp. 2618-2624 ◽  
Author(s):  
Lauren I. Richie Ehrlich ◽  
Thomas Serwold ◽  
Irving L. Weissman
Keyword(s):  
T Cell ◽  
The Other ◽  
In Vitro Assays ◽  
In Vivo Assays ◽  
Other Hand ◽  
Multipotent Progenitors ◽  
Lymphoid Progenitors

Abstract The identity of T-cell progenitors that seed the thymus has remained controversial, largely because many studies differ over whether these progenitors retain myeloid potential. Contradictory reports diverge in their use of various in vitro and in vivo assays. To consolidate these discordant findings, we compared the myeloid potential of 2 putative thymus seeding populations, common lymphoid progenitors (CLPs) and multipotent progenitors (MPPs), and the earliest intrathymic progenitor (DN1), using 2 in vitro assays and in vivo readouts. These assays gave contradictory results: CLP and DN1 displayed surprisingly robust myeloid potential on OP9-DL1 in vitro stromal cocultures but displayed little myeloid potential in vivo, as well as in methylcellulose cultures. MPP, on the other hand, displayed robust myeloid potential in all settings. We conclude that stromal cocultures reveal cryptic, but nonphysiologic, myeloid potentials of lymphoid progenitors, providing an explanation for contradictory findings in the field and underscoring the importance of using in vivo assays for the determination of physiologic lineage potentials.

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