scholarly journals The secretory membrane system in the Drosophila syncytial blastoderm embryo exists as functionally compartmentalized units around individual nuclei

2006 ◽  
Vol 173 (2) ◽  
pp. 219-230 ◽  
Author(s):  
David Frescas ◽  
Manos Mavrakis ◽  
Holger Lorenz ◽  
Robert DeLotto ◽  
Jennifer Lippincott-Schwartz
Keyword(s):  
Endoplasmic Reticulum ◽  
Drosophila Melanogaster ◽  
Plasma Membrane ◽  
Nuclear Division ◽  
Expression Patterns ◽  
Membrane System ◽  
Early Embryo ◽  
Golgi Membrane ◽  
Gene And Protein Expression ◽  
Secretory Products

Drosophila melanogaster embryogenesis begins with 13 nuclear division cycles within a syncytium. This produces >6,000 nuclei that, during the next division cycle, become encased in plasma membrane in the process known as cellularization. In this study, we investigate how the secretory membrane system becomes equally apportioned among the thousands of syncytial nuclei in preparation for cellularization. Upon nuclear arrival at the cortex, the endoplasmic reticulum (ER) and Golgi were found to segregate among nuclei, with each nucleus becoming surrounded by a single ER/Golgi membrane system separate from adjacent ones. The nuclear-associated units of ER and Golgi across the syncytial blastoderm produced secretory products that were delivered to the plasma membrane in a spatially restricted fashion across the embryo. This occurred in the absence of plasma membrane boundaries between nuclei and was dependent on centrosome-derived microtubules. The emergence of secretory membranes that compartmentalized around individual nuclei in the syncytial blastoderm is likely to ensure that secretory organelles are equivalently partitioned among nuclei at cellularization and could play an important role in the establishment of localized gene and protein expression patterns within the early embryo.

The nullo protein is a component of the actin-myosin network that mediates cellularization in Drosophila melanogaster embryos

1994 ◽  
Vol 107 (7) ◽  
pp. 1863-1873 ◽  
Author(s):  
M.A. Postner ◽  
E.F. Wieschaus
Keyword(s):  
Drosophila Melanogaster ◽  
Monoclonal Antibodies ◽  
Plasma Membrane ◽  
Nuclear Division ◽  
Leading Edge ◽  
The Other ◽  
Drosophila Embryogenesis ◽  
Zygotic Transcription ◽  
Hexagonal Network

After the 13th nuclear division cycle of Drosophila embryogenesis, cortical microfilaments are reorganized into a hexagonal network that drives the subsequent cellularization of the syncytial embryo. Zygotic transcription of the nullo and serendipity-alpha genes is required for normal structuring of the microfilament network. When either gene is deleted, the network assumes an irregular configuration leading to the formation of multinucleate cells. To investigate the role of these genes during cellularization, we have made monoclonal antibodies to both proteins. The nullo protein is present from cycle 13 through the end of cellularization. During cycle 13, it localizes between interphase actin caps and within metaphase furrows. In cellularizing embryos, nullo co-localizes with the actin-myosin network and invaginates along with the leading edge of the plasma membrane. The serendipity-alpha (sry-alpha) protein co-localizes with nullo protein to the hexagonal network but, unlike the nullo protein, it localizes to the sides rather than the vertices of each hexagon. Mutant embryos demonstrate that neither protein translationally regulates the other, but the localization of the sry-alpha protein to the hexagonal network is dependent upon nullo.

Relationship between the endoplasmic reticulum-Golgi membrane system and ubiquinone biosynthesis

1995 ◽  
Vol 1256 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Habtemichael Teclebrhan ◽  
Asa Jakobsson-Borin ◽  
Ulf Brunk ◽  
Gustav Dallner
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane System ◽  
Golgi Membrane

FINE STRUCTURE OF THE AGARICUS CARPOPHORE

1965 ◽  
Vol 43 (11) ◽  
pp. 1329-1333 ◽  
Author(s):  
M. S. Manocha
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Electron Microscope ◽  
Interphase Nucleus ◽  
Nuclear Division ◽  
Cross Wall ◽  
Food Reserve ◽  
Nuclear Membranes ◽  
Agaricus Campestris

The fine structure in the carpophore of the mushroom, Agaricus campestris, was studied with the electron microscope. The stipe consists of two types of cells (i) fundamental and (ii) long and thread-like. The pileus contains only the first type. The tramal cells of the gills are more elongated than broad, regularly arranged, and rich in cytoplasmic contents. The cross wall of the hyphal cells shows a conspicuous pore apparatus with dark septal swellings encased in the plasma membrane. The nuclear membranes are differentiated early during nuclear division and are highly alveolated around the interphase nucleus. In the maturing basidium, the mitochondria increase in number by division of pre-existing ones, and thus become small with few cristae. Numerous vacuoles appear in the upper portion of the basidium. Oil globules are also produced in the mature basidium but were not observed during the early stages of development of the basidium or in any other part of the carpophore. The young basidium has food reserve which is granular in nature. The basidiospore contains numerous large oil globules, few mitochondria, scanty endoplasmic reticulum, and a wall of three well-defined layers.

Role of Alternative Splicing in Generating Isoform Diversity Among Plasma Membrane Calcium Pumps

2001 ◽  
Vol 81 (1) ◽  
pp. 21-50 ◽  
Author(s):  
Emanuel E. Strehler ◽  
David A. Zacharias
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Alternative Splicing ◽  
Splice Variants ◽  
Expression Patterns ◽  
Pdz Domain ◽  
Genetically Engineered ◽  
Intracellular Loop ◽  
Differential Distribution ◽  
Calcium Pumps

Calcium pumps of the plasma membrane (also known as plasma membrane Ca2+-ATPases or PMCAs) are responsible for the expulsion of Ca2+ from the cytosol of all eukaryotic cells. Together with Na+/Ca2+ exchangers, they are the major plasma membrane transport system responsible for the long-term regulation of the resting intracellular Ca2+concentration. Like the Ca2+ pumps of the sarco/endoplasmic reticulum (SERCAs), which pump Ca2+ from the cytosol into the endoplasmic reticulum, the PMCAs belong to the family of P-type primary ion transport ATPases characterized by the formation of an aspartyl phosphate intermediate during the reaction cycle. Mammalian PMCAs are encoded by four separate genes, and additional isoform variants are generated via alternative RNA splicing of the primary gene transcripts. The expression of different PMCA isoforms and splice variants is regulated in a developmental, tissue- and cell type-specific manner, suggesting that these pumps are functionally adapted to the physiological needs of particular cells and tissues. PMCAs 1 and 4 are found in virtually all tissues in the adult, whereas PMCAs 2 and 3 are primarily expressed in excitable cells of the nervous system and muscles. During mouse embryonic development, PMCA1 is ubiquitously detected from the earliest time points, and all isoforms show spatially overlapping but distinct expression patterns with dynamic temporal changes occurring during late fetal development. Alternative splicing affects two major locations in the plasma membrane Ca2+ pump protein: the first intracellular loop and the COOH-terminal tail. These two regions correspond to major regulatory domains of the pumps. In the first cytosolic loop, the affected region is embedded between a putative G protein binding sequence and the site of phospholipid sensitivity, and in the COOH-terminal tail, splicing affects pump regulation by calmodulin, phosphorylation, and differential interaction with PDZ domain-containing anchoring and signaling proteins. Recent evidence demonstrating differential distribution, dynamic regulation of expression, and major functional differences between alternative splice variants suggests that these transporters play a more dynamic role than hitherto assumed in the spatial and temporal control of Ca2+ signaling. The identification of mice carrying PMCA mutations that lead to diseases such as hearing loss and ataxia, as well as the corresponding phenotypes of genetically engineered PMCA “knockout” mice further support the concept of specific, nonredundant roles for each Ca2+ pump isoform in cellular Ca2+ regulation.

Triple Fixation For Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 90-91 ◽  
Author(s):  
M. A. Hayat
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Beam ◽  
Plasma Membrane ◽  
Myelin Sheath ◽  
Good Deal ◽  
Granular Structure ◽  
Oxidizing Agent ◽  
Fixation Technique ◽  
Large Clusters

Potassium permanganate has been successfully employed to study membranous structures such as endoplasmic reticulum, Golgi, plastids, plasma membrane and myelin sheath. Since KMnO4 is a strong oxidizing agent, deposition of manganese or its oxides account for some of the observed contrast in the lipoprotein membranes, but a good deal of it is due to the removal of background proteins either by dehydration agents or by volatalization under the electron beam. Tissues fixed with KMnO4 exhibit somewhat granular structure because of the deposition of large clusters of stain molecules. The gross arrangement of membranes can also be modified. Since the aim of a good fixation technique is to preserve satisfactorily the cell as a whole and not the best preservation of only a small part of it, a combination of a mixture of glutaraldehyde and acrolein to obtain general preservation and KMnO4 to enhance contrast was employed to fix plant embryos, green algae and fungi.

COVID-19: Update on Pathogenesis and Treatment Strategies

2020 ◽  
Vol 16 (1) ◽  
pp. 1-5
Author(s):  
Rakesh K. Chauhan ◽  
Pramod K. Sharma ◽  
Shikha Srivastava
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Human Monoclonal Antibody ◽  
Cardiac Injury ◽  
Treatment Strategies ◽  
Severe Pneumonia ◽  
Ground Glass Opacity ◽  
Golgi Membrane ◽  
Virus Particles ◽  
Global Pandemic

COVID-19 (Coronavirus disease) is the most contagious virus, which has been characterized as a global pandemic by WHO. The pathological cycle of COVID-19 virus can be specified as RNAaemia, severe pneumonia, along with the Ground-glass opacity (GGO), and acute cardiac injury. The S protein of Coronavirus has been reported to be involved in the entry of the virus into the host cell, which can be accomplished by direct membrane fusion between the virus and plasma membrane. In the endoplasmic reticulum or Golgi membrane, the newly formed enveloped glycoproteins are introduced. The spread of disease occurs due to contact and droplets unleashed by the vesicles holding the virus particles combined with the plasma membrane to the virus released by the host. The present manuscript describes the pathogenesis of COVID-19 and various treatment strategies that include drugs such as chloroquine and hydroxychloroquine, an anti-malarial drug, antibodies: SARS-CoV-specific human monoclonal antibody CR3022 and plasma treatment facilitate the therapeutic effect.

scholarly journals Characterization of Interactions between the Soybean Salt-Stress Responsive Membrane-Intrinsic Proteins GmPIP1 and GmPIP2

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1312
Author(s):  
Jia Liu ◽  
Weicong Qi ◽  
Haiying Lu ◽  
Hongbo Shao ◽  
Dayong Zhang
Keyword(s):  
Plasma Membrane ◽  
Salt Stress ◽  
Salt Tolerance ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Gene Expression Profiles ◽  
Early Gene ◽  
Plant Responses ◽  
Constitutive Overexpression ◽  
Important Trait

Salt tolerance is an important trait in soybean cultivation and breeding. Plant responses to salt stress include physiological and biochemical changes that affect the movement of water across the plasma membrane. Plasma membrane intrinsic proteins (PIPs) localize to the plasma membrane and regulate the water and solutes flow. In this study, quantitative real-time PCR and yeast two-hybridization were engaged to analyze the early gene expression profiles and interactions of a set of soybean PIPs (GmPIPs) in response to salt stress. A total of 20 GmPIPs-encoding genes had varied expression profiles after salt stress. Among them, 13 genes exhibited a downregulated expression pattern, including GmPIP1;6, the constitutive overexpression of which could improve soybean salt tolerance, and its close homologs GmPIP1;7 and 1;5. Three genes showed upregulated patterns, including the GmPIP1;6 close homolog GmPIP1;4, when four genes with earlier increased and then decreased expression patterns. GmPIP1;5 and GmPIP1;6 could both physically interact strongly with GmPIP2;2, GmPIP2;4, GmPIP2;6, GmPIP2;8, GmPIP2;9, GmPIP2;11, and GmPIP2;13. Definite interactions between GmPIP1;6 and GmPIP1;7 were detected and GmPIP2;9 performed homo-interaction. The interactions of GmPIP1;5 with GmPIP2;11 and 2;13, GmPIP1;6 with GmPIP2;9, 2;11 and GmPIP2;13, and GmPIP2;9 with itself were strengthened upon salt stress rather than osmotic stress. Taken together, we inferred that GmPIP1 type and GmPIP2 type could associate with each other to synergistically function in the plant cell; a salt-stress environment could promote part of their interactions. This result provided new clues to further understand the soybean PIP–isoform interactions, which lead to potentially functional homo- and heterotetramers for salt tolerance.

scholarly journals Chromosome Unipolar Division and Low Expression of Tws May Cause Parthenogenesis of Rice Water Weevil (Lissorhoptrus oryzophilus Kuschel)

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 278
Author(s):  
Pengcheng Wang ◽  
Fangyuan Yang ◽  
Zhuo Ma ◽  
Runzhi Zhang
Keyword(s):  
Drosophila Melanogaster ◽  
Quantitative Pcr ◽  
Ovarian Tissue ◽  
Expression Patterns ◽  
Meiotic Spindle ◽  
Lissorhoptrus Oryzophilus ◽  
Rice Water Weevil ◽  
Rice Water ◽  
Beijing China ◽  
Low Expression

Rice water weevil (RWW) is divided into two types of population, triploid parthenogenesis and diploid bisexual reproduction. In this study, we explored the meiosis of triploid parthenogenesis RWW (Shangzhuang Town, Haidian District, Beijing, China) by marking the chromosomes and microtubules of parthenogenetic RWW oocytes via immunostaining. The immunostaining results show that there is a canonical meiotic spindle formed in the triploid parthenogenetic RWW oocytes, but chromosomes segregate at only one pole, which means that there is a chromosomal unipolar division during the oogenesis of the parthenogenetic RWW. Furthermore, we cloned the conserved sequences of parthenogenetic RWW REC8 and Tws, and designed primers based on the parthenogenetic RWW sequence to detect expression patterns by quantitative PCR (Q-PCR). Q-PCR results indicate that the expression of REC8 and Tws in ovarian tissue of bisexual Drosophila melanogaster is 0.98 and 10,000.00 times parthenogenetic RWW, respectively (p < 0.01). The results show that Tws had low expression in parthenogenetic RWW ovarian tissue, and REC8 was expressed normally. Our study suggests that the chromosomal unipolar division and deletion of Tws may cause parthenogenesis in RWW.

scholarly journals Synaptotagmins at the endoplasmic reticulum–plasma membrane contact sites maintain diacylglycerol homeostasis during abiotic stress

2021 ◽  
Author(s):  
Noemi Ruiz-Lopez ◽  
Jessica Pérez-Sancho ◽  
Alicia Esteban del Valle ◽  
Richard P Haslam ◽  
Steffen Vanneste ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Abiotic Stress ◽  
Fluorescent Protein ◽  
Mechanical Damage ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact ◽  
Green Fluorescent

Abstract Endoplasmic reticulum-plasma membrane contact sites (ER-PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER-PM protein tether synaptotagmin1 (SYT1) exhibit decreased plasma membrane (PM) integrity under multiple abiotic stresses such as freezing, high salt, osmotic stress and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER-PM tether that also functions in maintaining PM integrity. The ER-PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to wild type while the levels of most glycerolipid species remain unchanged. Additionally, the SYT1-green fluorescent protein (GFP) fusion preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work uncovers a SYT-dependent mechanism of stress adaptation counteracting the detrimental accumulation of diacylglycerol at the PM produced during episodes of abiotic stress.

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