scholarly journals 3D Dissection of Structural Membrane-Wall Contacts in Filamentous Moss Protonemata

2020 ◽  
Vol 22 (1) ◽  
pp. 158
Author(s):  
Dominik Harant ◽  
Ingeborg Lang
Keyword(s):  
Cell Wall ◽  
Physcomitrella Patens ◽  
Fluorescent Protein ◽  
Model Organism ◽  
Adjacent Cell ◽  
3D Reconstructions ◽  
Narrow Side ◽  
Moss Protonemata ◽  
Green Fluorescent ◽  
Cell Cell

In conventional light microscopy, the adjacent cell walls of filamentous moss protonemata are seen from its narrow side thereby obscuring the major area of cell–cell connection. Optical sectioning, segmentation and 3D reconstructions allow the tilting and rotation of intracellular structures thereby greatly improving our understanding of interaction between organelles, membranes and the cell wall. Often, the findings also allow for conclusions on the respective functions. The moss Physcomitrium (Physcomitrella) patens is a model organism for growth, development and morphogenesis. Its filamentous protonemata are ideal objects for microscopy. Here, we investigated the cell wall between two neighboring cells and the connection of membranes towards this wall after plasmolysis in 0.8 M mannitol. An m-green fluorescent protein (GFP)-HDEL cell line was used to visualize the endoplasmatic reticulum (ER), the plasma membrane (PM) was stained with FM4-64. Our studies clearly show the importance of cell–cell contacts in P. patens protonemata. In 86% of the investigated cell pairs, at least one of the protoplasts remained fully attached to the adjacent cell wall. By tilting of z-stacks, volume renderings and 3D reconstructions, we visualized the amount of attached/detached PM and ER components after plasmolysis and membrane piercings through the wall of cell neighbors.

scholarly journals Droplet- Rather than Aerosol-Mediated Dispersion Is the Primary Mechanism of Bacterial Transmission from Contaminated Hand-Washing Sink Traps

2018 ◽  
Vol 85 (2) ◽  
Author(s):  
Shireen M. Kotay ◽  
Rodney M. Donlan ◽  
Christine Ganim ◽  
Katie Barry ◽  
Bryan E. Christensen ◽  
...  
Keyword(s):  
Patient Care ◽  
Sampling Methods ◽  
Fluorescent Protein ◽  
Model Organism ◽  
Air Sampling ◽  
Multidrug Resistant ◽  
Hand Washing ◽  
Content Type ◽  
E Coli ◽  
Green Fluorescent

ABSTRACT An alarming rise in hospital outbreaks implicating hand-washing sinks has led to widespread acknowledgment that sinks are a major reservoir of antibiotic-resistant pathogens in patient care areas. An earlier study using green fluorescent protein (GFP)-expressing Escherichia coli (GFP-E. coli) as a model organism demonstrated dispersal from drain biofilms in contaminated sinks. The present study further characterizes the dispersal of microorganisms from contaminated sinks. Replicate hand-washing sinks were inoculated with GFP-E. coli, and dispersion was measured using qualitative (settle plates) and quantitative (air sampling) methods. Dispersal caused by faucet water was captured with settle plates and air sampling methods when bacteria were present on the drain. In contrast, no dispersal was captured without or in between faucet events, amending an earlier theory that bacteria aerosolize from the P-trap and disperse. Numbers of dispersed GFP-E. coli cells diminished substantially within 30 minutes after faucet usage, suggesting that the organisms were associated with larger droplet-sized particles that are not suspended in the air for long periods. IMPORTANCE Among the possible environmental reservoirs in a patient care environment, sink drains are increasingly recognized as a potential reservoir to hospitalized patients of multidrug-resistant health care-associated pathogens. With increasing antimicrobial resistance limiting therapeutic options for patients, a better understanding of how pathogens disseminate from sink drains is urgently needed. Once this knowledge gap has decreased, interventions can be engineered to decrease or eliminate transmission from hospital sink drains to patients. The current study further defines the mechanisms of transmission for bacteria that colonize sink drains.

scholarly journals Bacteriophage SP01 Gene Product 56 Inhibits Bacillus subtilis Cell Division by Interacting with FtsL and Disrupting Pbp2B and FtsW Recruitment

2020 ◽  
Vol 203 (2) ◽  
pp. e00463-20
Author(s):  
Amit Bhambhani ◽  
Isabella Iadicicco ◽  
Jules Lee ◽  
Syed Ahmed ◽  
Max Belfatto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Gene Product ◽  
Fluorescent Protein ◽  
Lytic Bacteriophage ◽  
Cell Wall Synthesis ◽  
Content Type ◽  
Ftsz Ring ◽  
Green Fluorescent

ABSTRACTPrevious work identified gene product 56 (gp56), encoded by the lytic bacteriophage SP01, as being responsible for inhibition of Bacillus subtilis cell division during its infection. Assembly of the essential tubulin-like protein FtsZ into a ring-shaped structure at the nascent site of cytokinesis determines the timing and position of division in most bacteria. This FtsZ ring serves as a scaffold for recruitment of other proteins into a mature division-competent structure permitting membrane constriction and septal cell wall synthesis. Here, we show that expression of the predicted 9.3-kDa gp56 of SP01 inhibits later stages of B. subtilis cell division without altering FtsZ ring assembly. Green fluorescent protein-tagged gp56 localizes to the membrane at the site of division. While its localization does not interfere with recruitment of early division proteins, gp56 interferes with the recruitment of late division proteins, including Pbp2b and FtsW. Imaging of cells with specific division components deleted or depleted and two-hybrid analyses suggest that gp56 localization and activity depend on its interaction with FtsL. Together, these data support a model in which gp56 interacts with a central part of the division machinery to disrupt late recruitment of the division proteins involved in septal cell wall synthesis.IMPORTANCE Studies over the past decades have identified bacteriophage-encoded factors that interfere with host cell shape or cytokinesis during viral infection. The phage factors causing cell filamentation that have been investigated to date all act by targeting FtsZ, the conserved prokaryotic tubulin homolog that composes the cytokinetic ring in most bacteria and some groups of archaea. However, the mechanisms of several phage factors that inhibit cytokinesis, including gp56 of bacteriophage SP01 of Bacillus subtilis, remain unexplored. Here, we show that, unlike other published examples of phage inhibition of cytokinesis, gp56 blocks B. subtilis cell division without targeting FtsZ. Rather, it utilizes the assembled FtsZ cytokinetic ring to localize to the division machinery and to block recruitment of proteins needed for septal cell wall synthesis.

scholarly journals Functional Characterization of a Drought-Responsive Invertase Inhibitor from Maize (Zea mays L.)

2019 ◽  
Vol 20 (17) ◽  
pp. 4081 ◽  
Author(s):  
Lin Chen ◽  
Xiaohong Liu ◽  
Xiaojia Huang ◽  
Wei Luo ◽  
Yuming Long ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fluorescent Protein ◽  
Functional Characterization ◽  
Protein Fusion ◽  
Drought Treatment ◽  
Vacuolar Invertase ◽  
Maize Leaves ◽  
Green Fluorescent ◽  
Proteinaceous Inhibitor

Invertases (INVs) play essential roles in plant growth in response to environmental cues. Previous work showed that plant invertases can be post-translationally regulated by small protein inhibitors (INVINHs). Here, this study characterizes a proteinaceous inhibitor of INVs in maize (Zm-INVINH4). A functional analysis of the recombinant Zm-INVINH4 protein revealed that it inhibited both cell wall and vacuolar invertase activities from maize leaves. A Zm-INVINH4::green fluorescent protein fusion experiment indicated that this protein localized in the apoplast. Transcript analysis showed that Zm-INVINH4 is specifically expressed in maize sink tissues, such as the base part of the leaves and young kernels. Moreover, drought stress perturbation significantly induced Zm-INVINH4 expression, which was accompanied with a decrease of cell wall invertase (CWI) activities and an increase of sucrose accumulation in both base parts of the leaves 2 to 7 days after pollinated kernels. In summary, the results support the hypothesis that INV-related sink growth in response to drought treatment is (partially) caused by a silencing of INV activity via drought-induced induction of Zm-INVINH4 protein.

scholarly journals Transient Coexpression of Individual Genes Encoded by the Triple Gene Block of Potato mop-top virus Reveals Requirements for TGBp1 Trafficking

2004 ◽  
Vol 17 (8) ◽  
pp. 921-930 ◽  
Author(s):  
Andrey A. Zamyatnin ◽  
Andrey G. Solovyev ◽  
Eugene I. Savenkov ◽  
Anna Germundsson ◽  
Maria Sandgren ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fluorescent Protein ◽  
Triple Gene Block ◽  
Terminal Region ◽  
Virus Movement ◽  
Cell Periphery ◽  
Movement Proteins ◽  
Gene Block ◽  
Potato Mop Top Virus ◽  
Green Fluorescent

TGBp1, TGBp2, and TGBp3, three plant virus movement proteins encoded by the “triple gene block” (TGB), may act in concert to facilitate cell-to-cell transport of viral RNA genomes. Transient expression of Potato mop-top virus (genus Pomovirus) movement proteins was used as a model to reconstruct interactions between TGB proteins. In bombarded epidermal cells of Nicotiana benthamiana, green fluorescent protein (GFP)-TGBp1 was distributed uniformly. However, in the presence of TGBp2 and TGBp3, GFP-TGBp1 was directed to intermediate bodies at the cell periphery, and to cell wall-embedded punctate bodies. Moreover, GFP-TGBp1 migrated into cells immediately adjacent to the bombarded cell. These data suggest that TGBp2 and TGBp3 mediate transport of GFP-TGBp1 to and through plasmodesmata. Mutagenesis of TGBp1 suggested that the NTPase and helicase activities of TGBp1 were not required for its transport to intermediate bodies directed by TGBp2 and TGBp3, but these activities were essential for the protein association with cell wall-embedded punctate bodies and translocation of TGBp1 to neighboring cells. The C-terminal region of TGBp1 was critical for trafficking mediated by TGBp2 and TGBp3. Mutation analysis also suggested an involvement of the TGBp2 C-terminal region in interactions with TGBp1.

scholarly journals Simvastatin Efficiently Reduces Levels of Alzheimer’s Amyloid Beta in Yeast

2019 ◽  
Vol 20 (14) ◽  
pp. 3531 ◽  
Author(s):  
Sudip Dhakal ◽  
Mishal Subhan ◽  
Joshua M. Fraser ◽  
Kenneth Gardiner ◽  
Ian Macreadie
Keyword(s):  
Fusion Protein ◽  
Amyloid Beta ◽  
Large Scale ◽  
Fluorescent Protein ◽  
Model Organism ◽  
Dependent Manner ◽  
Green Fluorescence ◽  
Convenient Means ◽  
Ergosterol Synthesis ◽  
Green Fluorescent

A large-scale epidemiology study on statins previously showed that simvastatin was unique among statins in reducing the incidence of dementia. Since amyloid beta (Aβ42) is the protein that is most associated with Alzheimer’s disease, this study has focused on how simvastatin influences the turnover of native Aβ42 and Aβ42 fused with green fluorescent protein (GFP), in the simplest eukaryotic model organism, Saccharomyces cerevisiae. Previous studies have established that yeast constitutively producing Aβ42 fused to GFP offer a convenient means of analyzing yeast cellular responses to Aβ42. Young cells clear the GFP fusion protein and do not have green fluorescence while the older population of cells retains the fusion protein and exhibits green fluorescence, offering a fast and convenient means of studying factors that affect Aβ42 turnover. In this study the proportion of cells having GFP fused to Aβ after exposure to simvastatin, atorvastatin and lovastatin was analyzed by flow cytometry. Simvastatin effectively reduced levels of the cellular Aβ42 protein in a dose-dependent manner. Simvastatin promoted the greatest reduction as compared to the other two statins. A comparison with fluconazole, which targets that same pathway of ergosterol synthesis, suggests that effects on ergosterol synthesis do not account for the reduced amounts of Aβ42 fused to GFP. The levels of native Aβ42 following treated with simvastatin were also examined using a more laborious approach, quantitative MALDI TOF mass spectrometry. Simvastatin efficiently reduced levels of native Aβ42 from the population. This work indicates a novel action of simvastatin in reducing levels of Aβ42 providing new insights into how simvastatin exerts its neuroprotective role. We hypothesize that this reduction may be due to protein clearance.

scholarly journals Mycelium-Like Networks Increase Bacterial Dispersal, Growth, and Biodegradation in a Model Ecosystem at Various Water Potentials

2016 ◽  
Vol 82 (10) ◽  
pp. 2902-2908 ◽  
Author(s):  
Anja Worrich ◽  
Sara König ◽  
Anja Miltner ◽  
Thomas Banitz ◽  
Florian Centler ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Model Organism ◽  
High Positive Correlation ◽  
Poor Knowledge ◽  
Content Type ◽  
Model Ecosystem ◽  
Microbial Ecosystems ◽  
Benzoate Degradation ◽  
Green Fluorescent ◽  
Bacterial Movement

ABSTRACTFungal mycelia serve as effective dispersal networks for bacteria in water-unsaturated environments, thereby allowing bacteria to maintain important functions, such as biodegradation. However, poor knowledge exists on the effects of dispersal networks at various osmotic (Ψo) and matric (Ψm) potentials, which contribute to the water potential mainly in terrestrial soil environments. Here we studied the effects of artificial mycelium-like dispersal networks on bacterial dispersal dynamics and subsequent effects on growth and benzoate biodegradation at ΔΨoand ΔΨmvalues between 0 and −1.5 MPa. In a multiple-microcosm approach, we used a green fluorescent protein (GFP)-tagged derivative of the soil bacteriumPseudomonas putidaKT2440 as a model organism and sodium benzoate as a representative of polar aromatic contaminants. We found that decreasing ΔΨoand ΔΨmvalues slowed bacterial dispersal in the system, leading to decelerated growth and benzoate degradation. In contrast, dispersal networks facilitated bacterial movement at ΔΨoand ΔΨmvalues between 0 and −0.5 MPa and thus improved the absolute biodegradation performance by up to 52 and 119% for ΔΨoand ΔΨm, respectively. This strong functional interrelationship was further emphasized by a high positive correlation between population dispersal, population growth, and degradation. We propose that dispersal networks may sustain the functionality of microbial ecosystems at low osmotic and matric potentials.

scholarly journals Immobilization of the Glycosylphosphatidylinositol-anchored Gas1 Protein into the Chitin Ring and Septum Is Required for Proper Morphogenesis in Yeast

2009 ◽  
Vol 20 (22) ◽  
pp. 4856-4870 ◽  
Author(s):  
Eleonora Rolli ◽  
Enrico Ragni ◽  
Julia Calderon ◽  
Silvia Porello ◽  
Umberto Fascio ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Separation ◽  
Fluorescent Protein ◽  
Transmembrane Domain ◽  
Cell Envelope ◽  
Phenotypic Analysis ◽  
Neck Size ◽  
Bud Neck ◽  
Green Fluorescent

Gas1p is a glucan-elongase that plays a crucial role in yeast morphogenesis. It is predominantly anchored to the plasma membrane through a glycosylphosphatidylinositol, but a fraction was also found covalently bound to the cell wall. We have used fusions with the green fluorescent protein or red fluorescent protein (RFP) to determine its localization. Gas1p was present in microdomains of the plasma membrane, at the mother-bud neck and in the bud scars. By exploiting the instability of RFP-Gas1p, we identified mobile and immobile pools of Gas1p. Moreover, in chs3Δ cells the chitin ring and the cross-linked Gas1p were missing, but this unveiled an additional unexpected localization of Gas1p along the septum line in cells at cytokinesis. Localization of Gas1p was also perturbed in a chs2Δ mutant where a remedial septum is produced. Phenotypic analysis of cells expressing a fusion of Gas1p to a transmembrane domain unmasked new roles of the cell wall-bound Gas1p in the maintenance of the bud neck size and in cell separation. We present evidence that Crh1p and Crh2p are required for tethering Gas1p to the chitin ring and bud scar. These results reveal a new mechanism of protein immobilization at specific sites of the cell envelope.

Involvement of a Rab8-like protein of Dictyostelium discoideum, Sas1, in the formation of membrane extensions, secretion and adhesion during development

Microbiology ◽  
2004 ◽  
Vol 150 (8) ◽  
pp. 2513-2525 ◽  
Author(s):  
Rhonda R. Powell ◽  
Lesly A. Temesvari
Keyword(s):  
Cell Adhesion ◽  
Dictyostelium Discoideum ◽  
Fluorescent Protein ◽  
Aggregate Size ◽  
Developmental Context ◽  
Cellular Events ◽  
Membrane Protrusions ◽  
A Cell ◽  
Green Fluorescent ◽  
Cell Cell

Establishment of cell–cell adhesions, regulation of actin, and secretion are critical during development. Rab8-like GTPases have been shown to modulate these cellular events, suggesting an involvement in developmental processes. To further elucidate the function of Rab8-like GTPases in a developmental context, a Rab8-related protein (Sas1) of Dictyostelium discoideum was examined, the expression of which increases at the onset of development. Dictyostelium cell lines expressing inactive (N128I mutant) and constitutively active (Q74L mutant) Sas1 as green fluorescent protein (GFP)-Sas1 chimeras were generated. Cells expressing Sas1Q74L displayed numerous actin-rich membrane protrusions, increased secretion, and were unable to complete development. In particular, these cells demonstrated a reduction in adhesion as well as in the levels of a cell adhesion molecule, gp24 (DdCAD-1). In contrast, cells expressing Sas1N128I exhibited increased cell–cell adhesion and increased levels of gp24. Counting factor is a multisubunit signalling complex that is secreted in early development and controls aggregate size by negatively regulating the levels of cell adhesion molecules, including gp24. Interestingly, the Sas1Q74L mutant demonstrated increased levels of extracellular countin, a subunit of counting factor, suggesting that Sas1 may regulate trafficking of counting factor components. Together, the data suggest that Sas1 may be a key regulator of actin, adhesion and secretion during development.

scholarly journals NEUROPHYSIOLOGICAL AND BEHAVIOURAL PERTURBATIONS IN Caenorhabditis elegans EXPOSED TO ORGANOPHOSPHATE PESTICIDES

2021 ◽  
Vol 9 (3) ◽  
pp. 343-352
Author(s):  
Rajul Jain ◽  
◽  
Priyanka Gautam ◽  
Keyword(s):  
Caenorhabditis Elegans ◽  
Fluorescent Protein ◽  
Developmental Toxicity ◽  
Yellow Fluorescent Protein ◽  
Model Organism ◽  
Egg Laying ◽  
High Exposure ◽  
C Elegans ◽  
Significant Difference ◽  
Green Fluorescent

The ubiquitous use of pesticides all over the world leads to adverse effects on both targets as well as non-target species. The extensive and uncontrolled use of organophosphates (OPs), a large group of pesticidal compounds in agricultural and household products are resulting in high exposure to humans. This research has been carried out to study the adverse effect of OPs i.e., chlorpyrifos, trichlorfon, and disulfoton on model organism Caenorhabditis elegans to evaluate their behavioural as well as developmental toxicity at different time intervals i.e., 4, 24, 48, and 72 hours (hrs) of exposure. A significant difference was observed in all the behavioural endpoints like locomotion, egg-laying, offspring count, and learning along with developmental parameters like mortality, paralysis, and growth rendering from moderate to high toxic effects. Based on the above screening, trichlorfon resulted in glutamatergic and cholinergic neurodegeneration along with elevated autofluorescence. Loss in Yellow fluorescent Protein (YFP) and Green Fluorescent Protein (GFP) was recorded by 57.96% and 30.52% using transgenic strains OH11124 (otIs388 [eat-4(fosmid)::SL2::YFP::H2B + (pBX)pha-1(+)] III) and OH13083 (otIs576 [unc-17(fosmid)::GFP + lin-44::YFP]). These results have shown the biological potency of toxicants in C. elegans and pave the way forward to provide insight into various neurogenerative diseases in humans.

Sign in / Sign up

Export Citation Format

Share Document