Cell Membrane Formation Research Articles

Micro-size cell-like vesicles based on gemini-like amphiphilic peptide

Since simple peptides are considered as basic building blocks for prebiotic organization, peptide vesicles may provide a new insight into the formation of the primitive cell membrane. Here, the formation of micro-sized cell-like vesicles through the fusion of small ones was demonstrated based on gemini-like amphiphilic peptides (GAPs) with cis double bonds of the alkyl tails. It might be due to the change of tightness of arrangement of GAPs in the bilayer membrane caused by the kinked cis double bonds.

Lipid Transport between the Endoplasmic Reticulum and Mitochondria

Mitochondria are partially autonomous organelles that depend on the import of certain proteins and lipids to maintain cell survival and membrane formation. Although phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine are synthesized by mitochondrial enzymes, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and sterols need to be imported from other organelles. The origin of most lipids imported into mitochondria is the endoplasmic reticulum, which requires interaction of these two subcellular compartments. Recently, protein complexes that are involved in membrane contact between endoplasmic reticulum and mitochondria were identified, but their role in lipid transport is still unclear. In the present review, we describe components involved in lipid translocation between the endoplasmic reticulum and mitochondria and discuss functional as well as regulatory aspects that are important for lipid homeostasis.

Microbubble-Enhanced Cell Membrane Permeability in High Gravity Field

Cell permeability controls the transportation of extracellular materials through cell membranes, which plays a critical role in drug and gene delivery. This work reports an innovative method to enhance the cell permeability through cell-bubble interactions in a high gravity field. In the presence of microbubbles, the cell membrane permeability of mammalian cells was significantly increased in the high gravity field, and up to 80% THP-1 and 70% MCF-7 cells were permeabilized by using FITC-Dextran with average molecular weight of 40 and 70 kDa as fluorescent markers which were found to locate in both cytoplasm and cell nucleus by using a confocal microscope. Micro-scale pores were detected on the cell membrane by a scanning electron microscope after the cell-microbubble interactions in the high gravity field. The delivery efficiency of FITC-Dextran could be further enhanced in gravity field of higher strength and in solutions with higher volume fraction of microbubbles, though the cell viability would also fall under extreme conditions. A simplified model was proposed to compare the contributions of surface forces (i.e., Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction force and membrane undulation force) with hydrodynamic force associated with cell-bubble interactions in the high gravity field. The hydrodynamic force was found to dominate the cell-bubble interaction while the DLVO force and membrane undulation force only play an important role at small separation (<10 nm) and low relative velocity of approach (i.e., low gravity field strength). The enhanced cell membrane permeability and formation of micro-scale pores are mainly due to the microbubble-cell interactions through collision and/or cavitation effects from the bursting of microbubbles. Our results have important implications in many bioengineering processes which are dependent on cell membrane permeability.

ISOLASI ASAM-9Z,12Z,15Z-OKTADEKATRIENOAT DARI BIJI SELASIH (Ocimum basilicum)

&lt;p&gt;The α-linolenic acid (9,12,15-octadecatrieonic acid) is omega-3 fatty acid that more active than other fatty acids to inhibit cell membrane damages, formation and growth of brain functions, antiinflamatory and prevent several cronic deseases like lung desease and arthrytis. Some research explain that geometri of omega-3 fatty acids had effect on its bioactivity. This research purpose was to isolate α-linolenic acid with geometry &lt;em&gt;Z,Z,Z &lt;/em&gt;(&lt;em&gt;9Z,12Z,15Z&lt;/em&gt;-oktadekatrienoat).&lt;/p&gt;&lt;p&gt;&lt;em&gt;O. basilicum &lt;/em&gt;seeds oil was isolated from &lt;em&gt;O. basilicum &lt;/em&gt;seeds using Soxhlet extraction with n-hexane, then hidrolized by 12 % solution of KOH in aquadest. The α-linolenic acid was separated from other fatty acids by urea inclusion methods. The optimum condition of urea inclusion was determined in various temperature (+ 5, + 3, + 1, + (-1), + (-3), + (-5))&lt;sup&gt;0&lt;/sup&gt;C and ratio of fatty acid : urea 1:1; 1:1,5; 1:2; 1:2,5; 1:3; 1:3,5; 1:4.&lt;/p&gt;&lt;p&gt;From this research, extraction of &lt;em&gt;O. basilicum &lt;/em&gt;seeds oil with n-hexane as solvent resulted clear yellow-brown oil with refractive indeks 1,466 and density 0,855 g/mL. Gas Chromatography (GC) analysis of fatty acids hidrolyzed from &lt;em&gt;O. basilicum &lt;/em&gt;oil showed peak at t&lt;sub&gt;R&lt;/sub&gt;= 19,949 minutes with relative percentage 70,72 %. Base on Mass Spectrum (MS), the fragmentation of this compound, with t&lt;sub&gt;R&lt;/sub&gt;= 19,949 minutes, was identic with &lt;em&gt;9Z,12Z,15Z&lt;/em&gt;-oktadecatrienoic acid.Isolation of α-linolenic acid from other fatty acids using urea inclusion at temperature 0-2 &lt;sup&gt;0&lt;/sup&gt;C dan rasio fatty acid: urea 1:1,5 showed nonadduct fraction contains compound with t&lt;sub&gt;R&lt;/sub&gt;= 19,980 minutes and relative percentage 88,51 %. Base on Mass Spectrum (MS), the fragmentation of this compound, with t&lt;sub&gt;R&lt;/sub&gt;= 19,980 minutes, was identic with &lt;em&gt;9Z,12Z,15Z&lt;/em&gt;-oktadecatrienoic acid.&lt;/p&gt;

Phenotype studies of Orf135 CTPase from E. coli and complementation studies with RV1160 from M. tuberculosis

We are studying the Nudix hydrolases from Mycobacterium tuberculosis as potential novel antibiotic targets. One such potential target is the CTPase Rv1160. Because it has a functional homolog in E. coli, Orf135 CTPase, we can study the phenotype of the orf135 E. coli knockout and carry out complementation studies with rv1160. CTP is a feedback inhibitor of pyrimidine biosynthesis, and a precursor to lipid biosynthesis, including cell membrane formation, thus Orf135 and Rv1160 may help regulate these pathways through degradation of CTP. The orf135 E. coli knockout is less susceptible to streptomycin, a phenotype consistent with a change in the cell membrane. The orf135 knockout mutant, containing a plasmid carrying rv1160, shows the same susceptibility to streptomycin as the wildtype E. coli, thus proving that Rv1160 complements Orf135. This research has been supported by an NIH AREA grant and an RIT College of Science summer fellowship.

Improving charge collection in Escherichia coli–carbon electrode devices with conjugated oligoelectrolytes

It is important to tailor biotic-abiotic interfaces in order to maximize the utility of bioelectronic devices such as microbial fuel cells (MFCs), electrochemical sensors and bioelectrosynthetic systems. The efficiency of electron-equivalent extraction (or injection) across such biotic-abiotic interfaces is dependent on the choice of the microbe and the conductive electrode material. In this contribution, we show that spontaneous intercalation of a conjugated oligoelectrolyte, namely 4,4'-bis(4'-(N,N-bis(6''-(N,N,N-trimethylammonium)hexyl)amino)-styryl)stilbene tetraiodide (DSSN+), into the membranes of Escherichia coli leads to an increase in current generation in MFCs containing carbon-based electrodes. A combination of scanning electron microscopy (SEM) and confocal microscopy was employed to confirm the incorporation of DSSN+ into the cell membrane and biofilm formation atop carbon felt electrodes. Current collection was enhanced by more than 300% with addition of this conjugated oligoelectrolyte. The effect of DSSN+ concentration on electrical output was also investigated. Higher concentrations, up to 25 μM, lead to an overall increase in the number of charge equivalents transferred to the charge-collecting electrode, providing evidence in support of the central role of the synthetic system in improving device performance.

Lovastatin inAspergillus terreus: Fermented Rice Straw Extracts Interferes with Methane Production and Gene Expression inMethanobrevibacter smithii

Lovastatin, a natural byproduct of some fungi, is able to inhibit HMG-CoA (3-hydroxy-3methyl glutaryl CoA) reductase. This is a key enzyme involved in isoprenoid synthesis and essential for cell membrane formation in methanogenic Archaea. In this paper, experiments were designed to test the hypothesis that lovastatin secreted by Aspergillus terreus in fermented rice straw extracts (FRSE) can inhibit growth and CH4 production in Methanobrevibacter smithii (a test methanogen). By HPLC analysis, 75% of the total lovastatin in FRSE was in the active hydroxyacid form, and in vitro studies confirmed that this had a stronger effect in reducing both growth and CH4 production in M. smithii compared to commercial lovastatin. Transmission electron micrographs revealed distorted morphological divisions of lovastatin- and FRSE-treated M. smithii cells, supporting its role in blocking normal cell membrane synthesis. Real-time PCR confirmed that both commercial lovastatin and FRSE increased (P < 0.01) the expression of HMG-CoA reductase gene (hmg). In addition, expressions of other gene transcripts in M. smithii. with a key involvement in methanogenesis were also affected. Experimental confirmation that CH4 production is inhibited by lovastatin in A. terreus-fermented rice straw paves the way for its evaluation as a feed additive for mitigating CH4 production in ruminants.

Screening for in vitro Cytotoxic Activity of Seaweed, Sargassum sp. Against Hep-2 and MCF-7 Cancer Cell Lines

Discovery of anticancer drugs that kill or disable tumor cells in the presence of normal cells without undue toxicity is a potential challenge for therapeutic care. Several papers in the literature have emphasized the potential implications of marine products such as seaweeds which exhibit antitumor activity. Study attempts to screen the antitumor effect of Sargassum sp, against chosen cell lines such as MCF-7 (Breast cancer) and Hep-2 (Liver Cancer). Ethanol extract of Sargassum sp. was concentrated using a Soxhlet apparatus and dissolved in DMSO. In vitro cytotoxic activity of Sargassum sp at various concentrations (100 μg/ml-300 μg/ml) screened for antitumor effect against the chosen cell lines using MTT assay (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, a yellow tetrazole). The study documented that the percentage of cell viability has been reduced with increased concentration, as evidenced by cell death. Sargassum sp extract shows potential cytotoxic activity (P≤0.05) with IC50 of 200 μ g/ml and 250 μg/ml against Hep-2 and MCF-7 cell lines respectively. The ethanol fraction of Sargassum sp induced cell shrinkage, cell membrane blebbing and formation of apoptotic bodies with evidence of bioactive components as profound influencing factors for anti-tumor effects. Further research need to be explored for the successful application of Sargassum sp as a potent therapeutic tool against cancer.

Systematic annotation and analysis of “virmugens”—Virulence factors whose mutants can be used as live attenuated vaccines

Live attenuated vaccines are usually generated by mutation of genes encoding virulence factors. “Virmugen” is coined here to represent a gene that encodes for a virulent factor of a pathogen and has been proven feasible in animal models to make a live attenuated vaccine by knocking out this gene. Not all virulence factors are virmugens. VirmugenDB is a web-based virmugen database (http://www.violinet.org/virmugendb). Currently, VirmugenDB includes 225 virmugens that have been verified to be valuable for vaccine development against 57 bacterial, viral, and protozoan pathogens. Bioinformatics analysis has revealed significant patterns in virmugens. For example, 10 Gram-negative and 1 Gram-positive bacterial aroA genes are virmugens. A sequence analysis has revealed at least 50% of identities in the protein sequences of the 10 Gram-negative bacterial aroA virmugens. As a pathogen case study, Brucella virmugens were analyzed. Out of 15 verified Brucella virmugens, 6 are related to carbohydrate or nucleotide transport and metabolism, and 2 involving cell membrane biogenesis. In addition, 54 virmugens from 24 viruses and 12 virmugens from 4 parasites are also stored in VirmugenDB. Virmugens tend to involve metabolism of nutrients (e.g., amino acids, carbohydrates, and nucleotides) and cell membrane formation. Host genes whose expressions were regulated by virmugen mutation vaccines or wild type virulent pathogens have also been annotated and systematically compared. The bioinformatics annotation and analysis of virmugens helps to elucidate enriched virmugen profiles and the mechanisms of protective immunity, and further supports rational vaccine design.

2-Arylbenzofuran-based molecules as multipotent Alzheimer's disease modifying agents

The complex etiology of Alzheimer's disease prompts scientists to develop multi-target strategies to combat causes and symptoms. In line with this modern paradigm and as a follow-up to our previous studies, we designed and synthesized a focused collection of new 2-arylbenzofurans and evaluated their biological properties towards specific targets involved in AD, namely human AChE and human BuChE, and Aβ fibril formation. Selected compounds were also tested for their ability to inhibit Aβ neurotoxicity in terms of neuronal viability loss, and to prevent Aβ peptide-binding to cell membrane and intracellular reactive oxygen species (ROS) formation. The different modifications introduced in the structure of our lead compound led to an increase in activity towards one or more of the selected targets: the anticholinesterase activity of some compounds was found to be significantly higher than previously obtained related molecules, and the compounds also proved to possess Aβ anti-aggregating properties and neuroprotective effects. The most interesting multi-target compounds were 18, and 1. Interestingly, 1 also showed good selectivity and moderate affinity for CB1 receptor, opening new perspectives in the field of research on AD, since cannabinoid ligands have been widely reported to have neuroprotective properties.

Water's response to the fear of water

Spectroscopic analysis reveals that, at low temperatures, hydrophobic molecules dissolved in water strengthen the hydrogen bonding between nearby water molecules. But at high temperatures, the reverse can be true. See Letter p.582 The hydrophobic interactions that prevent oil and water from mixing also play a central part in biological processes ranging from cell-membrane formation to protein folding and drug binding. Yet little is known about how an oil molecule changes the structure of water, and thus facilitates such processes. Joel Davis et al. report spectroscopic measurements revealing that at low temperatures, the water in hydrophobic hydration shells has greater tetrahedral order and fewer weak hydrogen bonds than the surrounding bulk water. As the temperature increases, this structure disappears and another appears that is more disordered and has weaker hydrogen bonds than the bulk — but only around nonpolar chains longer than ∼1 nanometre.

Transcriptional profiles of biliary epithelial cells from rat regenerating liver after partial hepatectomy

It has been widely accepted that hepatocytes are critical for liver regeneration (LR), but very little is known about the role of biliary epithelial cells (BECs) in this event, so this study aims to manifest the relevance of BECs with LR. High purity population of BECs was obtained using Percoll gradient centrifugation combined with immunomagnetic-bead separation technique. Transcriptional profiles of BECs from rat regenerating liver after 2/3 hepatectomy were monitored with rat genome 230 2.0 array. Microarray analysis results were evaluated by RT-PCR assays. Of all the genes on the array, 1262 known genes and 1026 unknown genes were related to LR. 79 of 1262 known genes showed a ≥ 20-fold change in expression level, mainly participating in primary metabolism and inflammatory response. In contrast to the regenerating liver, BEC division did not occur at proliferative phase of LR; alterations in nucleic acid, lipid and protein metabolism were significantly different from each other or within the same substance metabolism at different phases; the active signaling pathways in priming phase were mediated mainly by G protein-coupled receptor, small GTPase and Wnt receptor. Transport-related genes showed up-regulated expression mainly in priming and proliferative phases, possibly linked to cell membrane formation and transport function recovery of BECs in the late phase. In brief, comparative analysis of biological activities of BECs and the regenerating liver reveals that biological activities at the cellular level are not always consistent with those at tissue level, suggesting the necessity of cell level investigation on liver regeneration. Finally, expression of BEC markers in hepatocytes may suggest the potential of hepatocytes to transdifferentiate into BEC.

Miniaturised technologies for the development of artificial lipid bilayer systems

Artificially reproducing cellular environments is a key aim of synthetic biology, which has the potential to greatly enhance our understanding of cellular mechanisms. Microfluidic and lab-on-a-chip (LOC) techniques, which enable the controlled handling of sub-microlitre volumes of fluids in an automated and high-throughput manner, can play a major role in achieving this by offering alternative and powerful methodologies in an on-chip format. Such techniques have been successfully employed over the last twenty years to provide innovative solutions for chemical analysis and cell-, molecular- and synthetic- biology. In the context of the latter, the formation of artificial cell membranes (or artificial lipid bilayers) that incorporate membrane proteins within miniaturised LOC architectures offers huge potential for the development of highly sensitive molecular sensors and drug screening applications. The aim of this review is to give a comprehensive and critical overview of the field of microsystems for creating and exploiting artificial lipid bilayers. Advantages and limitations of three of the most popular approaches, namely suspended, supported and droplet-based lipid bilayers, are discussed. Examples are reported that show how artificial cell membrane microsystems, by combining together biological procedures and engineering techniques, can provide novel methodologies for basic biological and biophysical research and for the development of biotechnology tools.

Hypocholesterolaemia in Beta-Thalassaemia

Background: To assess the plasma total cholesterol of male and female β-thalassaemia patients. The plasma cholesterol of normal individual compared with the β-thalassaemia cases. Methods: From October 2010 to March 2011, we enrolled 36 consecutive patients with β-thalassaemia that visited District Head Hospital, Balasore and Odisha every month for routine examinations. The sample was collected in the EDTA vial (5 ml), immediately centrifuged at 5000 rpm for 5 min and supernatant (plasma) collected in to the microcentrifuge tube and stored in -20oC freezer for other biochemical experiment. We have used Infinite cholesterol kit. We also found 5 sickle patients and included them in our analysis. Results: Of the 36 thalassaemic patients, 25 were males (12 ± 5.91 years) and 11 were females (9.08 ± 4.32 years) with comparison to 30 normal cases (15-35 years). Data analysis revealed that total cholesterol level, in case of normal (178.8.5 ± 31.1mg/dl), in thalassaemic cases (135.8.6 ± 29.3mg/dl) and in case of 5 sickle patients (143.3 ± 15.7mg/dl). The total cholesterol levels in case of normal is high than that of thalassaemic and sickle patients. In case of thalassaemia cases the low total cholesterol is 47.4 mg/dl. The expected values of total cholesterol is <200 mg/dl. In case of thalassaemia the values are too low than expected values. The ‘t’ test data revealed that there is comparison of two mean of the sample (normal and thalassaemic) is negligible small. Conclusion: The present study revealed that the majority of males and females with beta-thalassaemia have their blood lipid levels within the normal range, and lower than the healthy individuals of the same age and population. Such low level of cholesterol in thalassaemic patients seems to reflect the inability of the organism to balance the increased cholesterol requirement for red cell membrane formation. It is conceivable that the availability of cholesterol, ordinarily used in steroid hormone synthesis to control hypercoagulability.

Preparation of Liposome Using Egg Yolk

In this study, 162 students in the 6 year Pharmacy Program at the School of Pharmacy, Iwate Medical University were asked to prepare liposomal preparations using chicken egg yolk and to evaluate their properties with the aim of developing novel liposomes. High-purity lecithins are generally used for preparing liposomes but they are expensive. On the other hand, egg yolk has various components, including lecithin and cholesterol, which are important components for the formation of liposomes, so it was hypothesized that liposomes prepared from egg yolk may participate in the formation of cell membrane in chicks. Both liposomes from egg yolk (YL) and from lecithin (LL) exhibited Malthesian crosses using a polarizing microscope and multilamellar vesicles were observed, confirming that liposomal preparations from egg yolk were useful. The particle size of YL was about 100 nm with one peak. Furthermore, the YL are believed to be viable under different conditions because the particle size did not change when they were prepared in buffers having different pH values. The results of these experiments indicate that liposomal preparations from egg yolk can serve as natural materials, although some obstacles remain. This is a unique approach for carrying out practical training in our 6 year pharmaceutical science program.

Gene Cloning and Homology Modeling of the 3-Oxoacyl-ACP Synthase from Aeromonas hydrophila for Drug Discovery

Fatty acid biosynthesis in the Aeromonas hydrophila plays an important role in the formation of cell membrane and cell viability. The 3-oxoacyl- acyl carrier protein (ACP) synthase fadH and fadB from A. hydrophila have contributed in the initiation and elongation of fatty acid biosynthesis. In this study, we have designed new set of primers for amplification of the open reading frame of fadH and fadB. Cloning and sequencing of these amplified genes, analyzed that the G+C content of fadH and fadB were 63.3% and 68.79% respectively. The homology modeling was performed to generate the 3- D structure of fadH and fadB; and showed that more than 90% amino acid residues in allowed region of Ramachandranan plot. These findings provide a new avenue for better understanding, the role of genes encoding proteins involved in the fatty acid biosynthesis and thereby using as a potential and novel target for structure based drug designing to control the infections of A. hydrophila.

Effects of vibration on the proteome expression of anterior cruciate ligament cells

Recent reports have suggested that vibration has beneficial effects on knee healing response; however, the biomechanism of these beneficial effects still need to be determined on the anterior cruciate ligament (ACL) cell level. In this study, we applied a 20 Hz vibration to ACL cells, which produced a 20% increase (P < 0.001) in cell activity and 17% increase (P < 0.001) in intracellular sulfated glycosaminoglycan levels. In the 20 Hz vibration-stimulated ACL cell group, eight up-regulated (100 ∼ 300%) protein spots were identified compared with the control group by proteomics analysis. Among these proteins, Annexin A2 and Prolyl 4 hydroxylase (PH4B) were shown to have a 71% and 16% higher expression, respectively, in the 20 Hz vibration-stimulated ACL cell group by Western blotting (P < 0.001). These results indicate that vibration produces a positive cellular environment, and Annexin A2 and prolyl 4 hydroxylase are expected to help ligament repair and ACL cell proliferation by controlling cell membrane and extracellular matrix formation.

Some properties of mixed sols of lecithin and lysolecithin.

Abstract The preparations of pure crystalline lecithin and lysolecithin are described. Mixed sols of these phosphatides have been prepared and their viscosities, stabilities to salts, and haemolytic activities have been examined. The viscosity results indicate a marked interaction between the two compounds in the aqueous sols. The salt stability and haemolysis results are used to support a theory of cell membrane formation.

Two novel meiotic restitution mechanisms in haploid maize (Zea mays L.)

Two original mechanisms of nuclear restitution related to different processes of meiotic division of pollen mother cells (PMCs) have been found in male meiosis of the lines of maize haploids no. 2903 and no. 2904. The first mechanism, which is characteristic of haploid no. 2903, consists in spindle deformation (bend) in the conventional metaphase-anaphase I. This leads to asymmetric incomplete cytokinesis with daughter cell membranes in the form of incisions on the mother cell membrane. As a result, the chromosomes of the daughter nuclei are combined into a common spindle during the second meiotic division, and a dyad of haploid microspores is formed at the tetrad stage. The frequency of this abnormality is about 50%. The second restitution mechanism, which has been observed in PMCs of haploid no. 2904, results from disturbance of the fusion of membrane vesicles (plastosomes) at the moment of formation of daughter cell membranes and completion of cytokinesis in the first meiotic division. This type of cell division yields a binuclear monad. In the second meiotic division, the chromosomes of the daughter nuclei form a common spindle, and meiosis results in a dyad of haploid microspores. The frequency of this abnormality is as high as 15%. As a result, haploid lines no. 2903 and no. 2904 partly restore fertility.

Asymmetric Mbc, active Rac1 and F-actin foci in the fusion-competent myoblasts during myoblast fusion inDrosophila

Myoblast fusion is an intricate process that is initiated by cell recognition and adhesion, and culminates in cell membrane breakdown and formation of multinucleate syncytia. In the Drosophila embryo, this process occurs asymmetrically between founder cells that pattern the musculature and fusion-competent myoblasts (FCMs) that account for the bulk of the myoblasts. The present studies clarify and amplify current models of myoblast fusion in several important ways. We demonstrate that the non-conventional guanine nucleotide exchange factor (GEF) Mbc plays a fundamental role in the FCMs, where it functions to activate Rac1, but is not required in the founder cells for fusion. Mbc, active Rac1 and F-actin foci are highly enriched in the FCMs, where they localize to the Sns:Kirre junction. Furthermore, Mbc is crucial for the integrity of the F-actin foci and the FCM cytoskeleton, presumably via its activation of Rac1 in these cells. Finally, the local asymmetric distribution of these proteins at adhesion sites is reminiscent of invasive podosomes and, consistent with this model, they are enriched at sites of membrane deformation, where the FCM protrudes into the founder cell/myotube. These data are consistent with models promoting actin polymerization as the driving force for myoblast fusion.