scholarly journals Novel Zebrafish Mono-α2,8-sialyltransferase (ST8Sia VIII): An Evolutionary Perspective of α2,8-Sialylation

2019 ◽  
Vol 20 (3) ◽  
pp. 622 ◽  
Author(s):  
Lan-Yi Chang ◽  
Elin Teppa ◽  
Maxence Noel ◽  
Pierre-André Gilormini ◽  
Mathieu Decloquement ◽  
...  
Keyword(s):  
Zebrafish Genome ◽  
Evolutionary Perspective ◽  
Human Homologue ◽  
Zebrafish Development ◽  
Neuronal Tissues ◽  
The Central Nervous System ◽  
And Function ◽  
Sialylated Glycoproteins

The mammalian mono-α2,8-sialyltransferase ST8Sia VI has been shown to catalyze the transfer of a unique sialic acid residues onto core 1 O-glycans leading to the formation of di-sialylated O-glycosylproteins and to a lesser extent to diSia motifs onto glycolipids like GD1a. Previous studies also reported the identification of an orthologue of the ST8SIA6 gene in the zebrafish genome. Trying to get insights into the biosynthesis and function of the oligo-sialylated glycoproteins during zebrafish development, we cloned and studied this fish α2,8-sialyltransferase homologue. In situ hybridization experiments demonstrate that expression of this gene is always detectable during zebrafish development both in the central nervous system and in non-neuronal tissues. Intriguingly, using biochemical approaches and the newly developed in vitro MicroPlate Sialyltransferase Assay (MPSA), we found that the zebrafish recombinant enzyme does not synthetize diSia motifs on glycoproteins or glycolipids as the human homologue does. Using comparative genomics and molecular phylogeny approaches, we show in this work that the human ST8Sia VI orthologue has disappeared in the ray-finned fish and that the homologue described in fish correspond to a new subfamily of α2,8-sialyltransferase named ST8Sia VIII that was not maintained in Chondrichtyes and Sarcopterygii.

scholarly journals Altered folate binding protein expression and folate delivery are associated with congenital hydrocephalus in the hydrocephalic Texas rat

2018 ◽  
Vol 39 (10) ◽  
pp. 2061-2073 ◽  
Author(s):  
Alicia Requena Jimenez ◽  
Naila Naz ◽  
Jaleel A Miyan
Keyword(s):  
Folate Receptor ◽  
Cortical Cell ◽  
Regulatory Function ◽  
Folate Binding Protein ◽  
In Vitro Proliferation ◽  
Cycle Arrest ◽  
Csf Levels ◽  
And Function

Hydrocephalus (HC) is an imbalance in cerebrospinal fluid (CSF) secretion/absorption resulting in fluid accumulation within the brain with consequential pathophysiology. Our research has identified a unique cerebral folate system in which depletion of CSF 10-formyl-tetrahydrofolate-dehydrogenase (FDH) is associated with cortical progenitor cell-cycle arrest in hydrocephalic Texas (H-Tx) rats. We used tissue culture, immunohistochemistry, in-situ PCR and RT-PCR and found that the in-vitro proliferation of arachnoid cells is highly folate-dependent with exacerbated proliferation occurring in hydrocephalic CSF that has low FDH but high folate-receptor-alpha (FRα) and folate. Adding FDH to this CSF prevented aberrant proliferation indicating a regulatory function of FDH on CSF folate concentration. Arachnoid cells have no detectable mRNA for FRα or FDH, but FDH mRNA is found in the choroid plexus (CP) and CSF microvesicles. Co-localization of FDH, FRα and folate suggests important functions of FDH in cerebral folate transport, buffering and function. In conclusion, abnormal CSF levels of FDH, FRα and folate inhibit cortical cell proliferation but allow uncontrolled arachnoid cell division that should increase fluid absorption by increasing the arachnoid although this fails in the hydrocephalic brain. FDH appears to buffer available folate to control arachnoid proliferation and function.

Combinatorial in vitro RNAi of two neuropeptide genes and a pharyngeal gland gene on Meloidogyne incognita

Nematology ◽  
2015 ◽  
Vol 17 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Prakash Banakar ◽  
Amita Sharma ◽  
Catherine J. Lilley ◽  
Nagavara Prasad Gantasala ◽  
Mukesh Kumar ◽  
...  
Keyword(s):  
Meloidogyne Incognita ◽  
Parasitic Nematodes ◽  
Specific Gene ◽  
Plant Parasitic Nematodes ◽  
Rnai Silencing ◽  
Transcript Quantification ◽  
The Central Nervous System ◽  
Pharyngeal Gland

Root-knot nematodes are the most economically important group of plant-parasitic nematodes. In the present study, functional validation using in vitro RNAi was carried out on Meloidogyne incognita with two FMRFamide-like peptide genes, flp-14 and flp-18, and a subventral pharyngeal gland specific gene, 16D10. It was found that RNAi silencing of each gene reduced the attraction of M. incognita at different time intervals both in combination and individually. Silencing of the genes reduced nematode infection by 23-30% and development as indicated by a reduction in the number of females by 26-62%. Reproduction was decreased by 27-73% and fecundity was decreased by 19-51%. In situ hybridisation revealed the expression of flp-18 in cells associated with the ventral and retro vesicular ganglia of the central nervous system. qRT-PCR supported the correlation between phenotypic effects of silencing with that of transcript quantification.

scholarly journals Autophosphorylation of Tyr397 and its phosphorylation by Src-family kinases are altered in focal-adhesion-kinase neuronal isoforms

2000 ◽  
Vol 348 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Madeleine TOUTANT ◽  
Jeanne-Marie STUDLER ◽  
Ferran BURGAYA ◽  
Alicia COSTA ◽  
Pascal EZAN ◽  
...  
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Fluorescent Protein ◽  
Focal Adhesions ◽  
Src Family Kinases ◽  
Critical Residue ◽  
Green Fluorescent ◽  
And Function

In brain, focal adhesion kinase (FAK) is regulated by neurotransmitters and has a higher molecular mass than in other tissues, due to alternative splicing. Two exons code for additional peptides of six and seven residues (‘boxes’ 6 and 7), located on either side of Tyr397, which increase its autophosphorylation. Using in situ hybridization and a monoclonal antibody (Mab77) which does not recognize FAK containing box 7, we show that, although mRNAs coding for boxes 6 and 7 have different patterns of expression in brain, FAK+6,7 is the main isoform in forebrain neurons. The various FAK isoforms fused to green fluorescent protein were all targeted to focal adhesions in non-neuronal cells. Phosphorylation-state-specific antibodies were used to study in detail the phosphorylation of Tyr397, a critical residue for the activation and function of FAK. The presence of boxes 6 and 7 increased autophosphorylation of Tyr397 independently and additively, whereas they had a weak effect on FAK kinase activity towards poly(Glu,Tyr). Src-family kinases were also able to phosphorylate Tyr397 in cells, but this phosphorylation was decreased in the presence of box 6 or 7, and abolished in the presence of both. Thus the additional exons characteristic of neuronal isoforms of FAK do not alter its targeting, but change dramatically the phosphorylation of Tyr397. They increase its autophosphorylation in vitro and in transfected COS-7 cells, whereas they prevent its phosphorylation when co-transfected with Src-family kinases.

scholarly journals Developmental Regulation of Human Cytomegalovirus Receptors in Cytotrophoblasts Correlates with Distinct Replication Sites in the Placenta

2007 ◽  
Vol 81 (9) ◽  
pp. 4701-4712 ◽  
Author(s):  
Ekaterina Maidji ◽  
Olga Genbacev ◽  
Hsin-Ti Chang ◽  
Lenore Pereira
Keyword(s):  
Developmental Regulation ◽  
Growth Factor Receptor ◽  
Chorionic Villi ◽  
Susceptibility To Infection ◽  
Focal Infection ◽  
Replication Sites ◽  
Epidermal Growth ◽  
And Function

ABSTRACT Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and developing placenta and spreads to the fetus throughout gestation. Virus replicates in invasive cytotrophoblasts in the decidua, and maternal immunoglobulin G (IgG)-CMV virion complexes, which are transcytosed by the neonatal Fc receptor across syncytiotrophoblasts, infect underlying cytotrophoblasts in chorionic villi. Immunity is central to protection of the placenta-fetal unit: infection can occur when IgG has a low neutralizing titer. Here we used immunohistochemical and function-blocking methods to correlate infection in the placenta with expression of potential CMV receptors in situ and in vitro. In placental villi, syncytiotrophoblasts express the virion receptor epidermal growth factor receptor (EGFR) but lack integrin coreceptors, and virion uptake occurs without replication. Focal infection can occur when transcytosed virions reach EGFR-expressing cytotrophoblasts that selectively initiate expression of αV integrin. In cell columns, proximal cytotrophoblasts lack receptors and distal cells express integrins α1β1 and αVβ3, enabling virion attachment. In the decidua, invasive cytotrophoblasts expressing coreceptors upregulate EGFR, thereby dramatically increasing susceptibility to infection. Our findings indicate that virion interactions with cytotrophoblasts expressing receptors in the placenta (i) change as the cells differentiate and (ii) correlate with spatially distinct sites of CMV replication in maternal and fetal compartments.

scholarly journals Histamine H2 receptor radioligands: triumphs and challenges

2021 ◽  
Author(s):  
Steffen Pockes ◽  
Katharina Tropmann
Keyword(s):  
Receptor Expression ◽  
In Vitro Assays ◽  
Histamine H2 Receptor ◽  
Drug Candidates ◽  
Carbon 14 ◽  
The Central Nervous System ◽  
And Function ◽  
Role And Function

Since the discovery of the histamine H2 receptor (H2R), radioligands were among the most powerful tools to investigate its role and function. Initially, radiolabeling was used to investigate human and rodent tissues regarding their receptor expression. Later, radioligands gained increasing significance as pharmacological tools in in vitro assays. Although tritium-labeling was mainly used for this purpose, labeling with carbon-14 is preferred for metabolic studies of drug candidates. After the more-or-less successful application of numerous labeled H2R antagonists, the recent development of the G protein-biased radioligand [3H]UR-KAT479 represents another step forward to elucidate the widely unknown role of the H2R in the central nervous system through future studies.

scholarly journals The diversity and function of sourdough starter microbiomes

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Elizabeth A Landis ◽  
Angela M Oliverio ◽  
Erin A McKenney ◽  
Lauren M Nichols ◽  
Nicole Kfoury ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
Acetic Acid Bacteria ◽  
Fermented Food ◽  
Microbial Interactions ◽  
Structure Variation ◽  
Biogeographic Patterns ◽  
And Function ◽  
Occurrence Patterns

Humans have relied on sourdough starter microbial communities to make leavened bread for thousands of years, but only a small fraction of global sourdough biodiversity has been characterized. Working with a community-scientist network of bread bakers, we determined the microbial diversity of 500 sourdough starters from four continents. In sharp contrast with widespread assumptions, we found little evidence for biogeographic patterns in starter communities. Strong co-occurrence patterns observed in situ and recreated in vitro demonstrate that microbial interactions shape sourdough community structure. Variation in dough rise rates and aromas were largely explained by acetic acid bacteria, a mostly overlooked group of sourdough microbes. Our study reveals the extent of microbial diversity in an ancient fermented food across diverse cultural and geographic backgrounds.

A role for netrin-1 in the guidance of cortical efferents

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 5063-5074 ◽  
Author(s):  
C. Metin ◽  
D. Deleglise ◽  
T. Serafini ◽  
T.E. Kennedy ◽  
M. Tessier-Lavigne
Keyword(s):  
Short Range ◽  
Collagen Gel ◽  
Collagen Gels ◽  
Ganglionic Eminence ◽  
Promoting Effect ◽  
Initial Portion ◽  
Diffusible Factor ◽  
The Central Nervous System

An intermediate target for axons leaving the cerebral cortex in embryonic mammals is the ganglionic eminence (GE), the embryonic precursor of the basal ganglia. The cues that direct these axons over the initial portion of their trajectory are not well understood, but could include both short-range and long-range attractants and repellents. In the present study, we provide evidence that corticofugal axons might be guided at least partly by a diffusible factor or factors originating in the lateral GE and the sulcus between the lateral and medial ridges of the GE (ISS), as well as evidence implicating the axonal chemoattractant netrin-1 in mediating these effects. Explants of lateral GE and ISS obtained from E12.5 and E13.5 mouse forebrain have a strong effect on both the outgrowth and orientation of corticofugal axons when cultured at a distance with explants of embryonic cortex in collagen gels. Netrin-1 mRNA is detected in these target tissues by in situ hybridization, and both netrin-1 protein and heterologous cells secreting netrin-1 can mimic the outgrowth-promoting effect of these target tissues in vitro. Furthermore, the growth of corticofugal axons is oriented toward an ectopic source of netrin-1 in vitro, and a function blocking anti-netrin-1 antiserum specifically abolishes the cortical axon outgrowth elicited by explants of lateral GE and the ISS in collagen gel cocultures. Taken together, these results suggest a role for netrin-1 in the attraction at a distance of early cortical axons by the GE. Thus in mammals -- as is also observed in nematodes -- the development of non-commissural projections in anterior regions of the embryo might be directed by mechanisms similar to those involved in directing the development of commissural projections in more posterior regions of the central nervous system.

Stromal Cell Types: Characterization and Function In Situ and In Vitro

Hematology ◽  
1999 ◽  
Vol 4 (3) ◽  
pp. 239-240
Author(s):  
Joel Greenberger ◽  
Armand Keating
Keyword(s):  
Stromal Cell ◽  
Cell Types ◽  
And Function

scholarly journals Stimulation of the neurotrophin receptor TrkB on astrocytes drives nitric oxide production and neurodegeneration

2012 ◽  
Vol 209 (3) ◽  
pp. 521-535 ◽  
Author(s):  
Emanuela Colombo ◽  
Chiara Cordiglieri ◽  
Giorgia Melli ◽  
Jia Newcombe ◽  
Markus Krumbholz ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
White Matter Lesions ◽  
Neurotrophin Receptor ◽  
Autoimmune Encephalomyelitis ◽  
Vitro Assay ◽  
Neurodegenerative Process ◽  
The Central Nervous System ◽  
And Function ◽  
Experimental Autoimmune

Neurotrophin growth factors support neuronal survival and function. In this study, we show that the expression of the neurotrophin receptor TrkB is induced on astrocytes in white matter lesions in multiple sclerosis (MS) patients and mice with experimental autoimmune encephalomyelitis (EAE). Surprisingly, mice lacking TrkB specifically in astrocytes were protected from EAE-induced neurodegeneration. In an in vitro assay, astrocytes stimulated with the TrkB agonist brain-derived neurotrophic factor (BDNF) released nitric oxide (NO), and conditioned medium from activated astrocytes had detrimental effects on the morphology and survival of neurons. This neurodegenerative process was amplified by NO produced by neurons. NO synthesis in the central nervous system during EAE depended on astrocyte TrkB. Together, these findings suggest that TrkB expression on astrocytes may represent a new target for neuroprotective therapies in MS.

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