scholarly journals Transcriptional response to kairomone exposure in Daphnia magna: A candidate gene approach

2020 ◽  
Author(s):  
Murat Telli ◽  
Donna M. Gordon ◽  
Ercan Selçuk Ünlü
Keyword(s):  
Daphnia Magna ◽  
Time Course ◽  
Biological Activities ◽  
Predatory Fish ◽  
Candidate Gene Approach ◽  
Late Time ◽  
Mrna Transcript ◽  
Transcript Levels ◽  
Fish Kairomone ◽  
Ideal System

Abstract Background: Daphnia (Brachiopoda, Cladocera) is a well-studied model organism providing unparalleled opportunity to test epigenetic regulation of predator avoidance mechanisms in aquatic ecosystems. The discovery of regulatory functions for microRNA molecules and recently described miRNA profiles of Daphnia make it an ideal system to probe for posttranslational regulatory mechanisms mediated by kairomone released by predatory fish. However, despite a number of studies that focused on mRNA transcript level differences, no miRNA studies associated with kairomone exposure have been reported. Results: Exposing D. magna to fish kairomone from birth to the first reproduction was found to result in the differential expression of the four miRNAs tested: miR-7, miR-34, miR-317, and miR-375. Normalized transcript levels for each miRNA were found to vary across the exposure period with no clear conserved pattern of expression despite functional target analyses by GO, COG and KEGG indicating that predicted miRNA target genes are likely involved in related biological activities. Analysis of six mRNA transcripts (Hsp70, Hsp90, actin, AKT, GYS and IGFR), identified in previous studies as kairomone-mediated genes in Daphnia magna, were also carried out. Similar to that obtained for miRNAs, the mRNA transcript levels showed varying degrees of temporal regulation across the exposure time course with the two heat shock transcripts exhibiting elevated levels at early and late time points of kairomone exposure while the AKT, GYS, and IGFR transcripts had an general decrease in expression during the first 96 hours. Conclusions: Differential mRNA expression data supports the premise of an ecological trade-off between the cost of general biological processes and that of survival under long-term kairomone stress. Transcript levels for the four miRNAs tested were found to vary across developmental time with kairomone exposure which suggests that they may have a role in regulating morphological, behavioral or physiological responses by altering target gene expression. These studies lay the foundation for future work aimed at linking miRNAs and their target transcripts to changes in the signaling events that govern Daphnia response to kairomone specific stress.

scholarly journals Simultaneous Optimal Production of Flavonol Aglycones and Degalloylated Catechins from Green Tea Using a Multi-Function Food-Grade Enzyme

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 861
Author(s):  
Chan-Su Rha ◽  
Shin-Woo Kim ◽  
Kyoung Hee Byoun ◽  
Yong Deog Hong ◽  
Dae-Ok Kim
Keyword(s):  
Green Tea ◽  
Time Course ◽  
Biological Activities ◽  
Hydrolase Activity ◽  
Enzyme Specificity ◽  
Optimum Conditions ◽  
Enzymatic Process ◽  
Food Grade ◽  
Phytochemical Compounds ◽  
Kaempferol Glycosides

(1) Background: Green tea (GT) contains well-known phytochemical compounds; namely, it is rich in flavan-3-ols (catechins) and flavonols comprising all glycoside forms. These compounds in GT might show better biological activities after a feasible enzymatic process, and the process on an industrial scale should consider enzyme specificity and cost-effectiveness. (2) Methods: In this study, we evaluated the most effective method for the enzymatic conversion of flavonoids from GT extract. One enzyme derived from Aspergillus niger (molecular weight 80–90 kDa) was ultimately selected, showing two distinct but simultaneous activities: intense glycoside hydrolase activity via deglycosylation and weak tannin acyl hydrolase activity via degalloylation. (3) Results: The optimum conditions for producing flavonol aglycones were pH 4.0 and 50 °C. Myricetin glycosides were cleaved 3.7–7.0 times faster than kaempferol glycosides. Flavonol aglycones were produced effectively by both enzymatic and hydrochloride treatment in a time-course reaction. Enzymatic treatment retained 80% (w/w) catechins, whereas 70% (w/w) of catechins disappeared by hydrochloride treatment. (4) Conclusions: This enzymatic process offers an effective method of conditionally producing flavonol aglycones and de-galloylated catechins from conversion of food-grade enzyme.

Effect of Prostaglandin on the Composition of Chinchilla Middle Ear Effusion

1980 ◽  
Vol 89 (3_suppl) ◽  
pp. 153-160 ◽  
Author(s):  
Timothy T. K. Jung ◽  
S. K. Juhn ◽  
Douglas M. Smith ◽  
Jonathan M. Gerrard
Keyword(s):  
Alkaline Phosphatase ◽  
Bone Resorption ◽  
Otitis Media ◽  
Middle Ear ◽  
Time Course ◽  
Unsaturated Fatty Acids ◽  
Biological Activities ◽  
Middle Ear Mucosa ◽  
Acid And Alkaline Phosphatase ◽  
Wide Range

Prostaglandins (PGs) are naturally occurring, cyclic, unsaturated fatty acids which possess a wide range of potent biological activities. PGs have been found in human middle ear effusions and might have implications for understanding the inflammation and possibly the bone resorption seen in chronic otitis media. We have measured PGs by radioimmunoassay in middle ear effusions (MEE) from experimentally induced serous otitis media (SOM) and purulent otitis media (POM) in chinchillas. PGE2 levels were significantly higher in the POM group compared to the SOM group. We have also demonstrated that chinchilla middle ear mucosa can convert arachidonic acid (AA), a precursor of PGs, to PG by injecting 14C-AA into bullae and assaying using radiochromatography. This conversion was completely blocked by both indomethacin and aspirin given orally or by direct injection into the middle ear. We then injected 50 μg of PGE2 into chinchilla bullae to assess its effect on the composition of MEE. First, the time course of PGE2 metabolism after its injection into the middle ear (ME) was determined by thin-layer chromatography (TLC) of labelled and unlabelled PGE2. Following this, serial daily injections of PGE2 and normal saline as control were made for one, three, and seven days. MEE and serum were collected and assayed for lactate dehydrogenase (LDH), acid and alkaline phosphatase, calcium, protein and hexosamine. Compared to the control, the levels of LDH, acid and alkaline phosphatase, calcium and protein were significantly elevated. Hexosamine levels were higher than the control at one and three days but did not differ significantly at seven days from the control. We have therefore demonstrated that chinchilla middle ear mucosa has the ability to synthesize PG from AA and suggest an active role for PGs in the inflammation and in the bone resorption seen in otitis media.

scholarly journals Impact of Malignancies in the Early and Late Time Course of Takotsubo Cardiomyopathy

2016 ◽  
Vol 80 (10) ◽  
pp. 2192-2198 ◽  
Author(s):  
Mélanie Girardey ◽  
Laurence Jesel ◽  
Umberto Campia ◽  
Nathan Messas ◽  
Sébastien Hess ◽  
...  
Keyword(s):  
Takotsubo Cardiomyopathy ◽  
Time Course ◽  
Late Time

Specificity of Smad Signaling during Primitive Erythropoiesis.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2785-2785
Author(s):  
Brian T. Zafonte ◽  
Tara L. Huber ◽  
Gordon Keller ◽  
Todd Evans
Keyword(s):  
Embryoid Body ◽  
Biological Activities ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cell ◽  
Dominant Negative ◽  
Hematopoietic Progenitors ◽  
Transcript Levels ◽  
Wide Range ◽  
Primitive Erythropoiesis

Abstract Bone morphogenetic proteins (BMPs) comprise a sub-family of TGF-beta-like molecules that exert a wide range of biological activities during development, and are essential for normal hematopoiesis. However, the precise stage in development that BMP signaling regulates hematopoiesis is not defined. Three proteins, Smad1, Smad5, and Smad8 transmit BMP signals to the nucleus to activate the expression of hematopoietic-specific transcription factors. These Smads are homologous in their sequences, and appear to be regulated similarly, however their specificity in regulating hematopoiesis remains undefined. Although Smad proteins are regulated post-translationally, their expression is also under transcriptional control during development. We examined the specificity of Smad1/5/8 activity in the context of primitive erythropoiesis, using the mouse embryonic stem cell /embryoid body (ES/EB) system. We exploited ES cells with GFP targeted to the brachyury locus, in order to identify specific sub-sets of progenitors. Smad1 transcript levels are initially upregulated as ES cells become fated to mesoderm and hematopoietic progenitors, but the levels are significantly decreased in cells derived from differentiating primitive erythroid colonies. In contrast, Smad5 transcript levels show the opposite profile, being more correlated with erythroid differentiation. To directly assess the role of these Smads during erythropoiesis, their activity is being manipulated in ES cells during the commitment phases of embryonic hematopoiesis. For this purpose, inducible ES cell lines were generated capable of forcing the expression of wildtype Smad1 or Smad5, or a dominant-negative isoform of Smad5, at any stage of ES/EB development. Colony assays were used to analyze quantitatively the hematopoietic potential of these cells. Forced expression of Smad1 results in a marked increase in primitive red blood cell colony formation as compared to control ES cells. Maintenance of Smad1 expression does not appear to inhibit terminal differentiation. Based on a time-study of the induction, the effect on erythoid colonies could be due to expansion of earlier progenitors. Current experiments using the in vitro blast assay are examining the direct effect of Smad1 expression on earlier (hemangioblast) development. This data, and analogous analyses of cells induced to express Smad5 or the dominant-negative Smad isoform are in progress and will be presented. These studies should facilitate our understanding of the specificity of BMP-regulated Smads during commitment and differentiation of embryonic stem cells and hematopoietic progenitors.

scholarly journals The histone demethylase KDM5 is essential for larval growth in Drosophila

2018 ◽  
Author(s):  
Coralie Drelon ◽  
Helen M. Belalcazar ◽  
Julie Secombe
Keyword(s):  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Biological Activities ◽  
Larval Growth ◽  
Imaginal Discs ◽  
Complete Loss ◽  
Histone Demethylase ◽  
Ideal System ◽  
Demethylase Activity ◽  
Regulated Gene Expression

AbstractRegulated gene expression is necessary for developmental and homeostatic processes. The KDM5 family of proteins are histone H3 lysine 4 demethylases that can regulate transcription through both demethylase-dependent and independent mechanisms. While loss and overexpression of KDM5 proteins are linked to intellectual disability and cancer, respectively, their normal developmental functions remain less characterized. Drosophila melanogaster provides an ideal system to investigate KDM5 function, as it encodes a single ortholog in contrast to the four paralogs found in mammalian cells. To examine the consequences of complete loss of KDM5, we generated a null allele of Drosophila kdm5, also known as little imaginal discs (lid), and show that it is essential for development. Animals lacking KDM5 die during late pupal development but show a dramatically delayed larval development that coincides with decreased proliferation and increased cell death in imaginal discs. Interestingly, this developmental delay is independent of the well-characterized Jumonji C (JmjC) domain-encoded histone demethylase activity and plant homedomain (PHD) motif-mediated chromatin binding activities of KDM5, suggesting key functions for less characterized domains. Consistent with the phenotypes observed, transcriptome analyses of kdm5 null mutant wing imaginal discs revealed the dysregulation of genes involved in several cellular processes, including cell cycle progression and DNA repair. Together, our data provide the first description of complete loss of KDM5 function in a metazoan and offer an invaluable tool for defining the biological activities of KDM5 family proteins.

scholarly journals Relationship of Structure and Biological Activity of Monosaccharide Lipid A Analogues to Induction of Nitric Oxide Production by Murine Macrophage RAW264.7 Cells

1998 ◽  
Vol 66 (12) ◽  
pp. 5792-5798 ◽  
Author(s):  
Keiji Funatogawa ◽  
Motohiro Matsuura ◽  
Masayasu Nakano ◽  
Makoto Kiso ◽  
Akira Hasegawa
Keyword(s):  
Nitric Oxide ◽  
Time Course ◽  
Lipid A ◽  
Biological Activities ◽  
Suppressive Effect ◽  
No Production ◽  
Murine Macrophage ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Relationship Of

ABSTRACT Lipid A is the active center of bacterial lipopolysaccharide (LPS), which exhibits diverse biological activities via the production of various mediators. We investigated the production of nitric oxide (NO), one of the mediators, by a murine macrophage cell line, RAW264.7, upon stimulation with a series of monosaccharide lipid A analogues to elucidate the relationship of structure and activity in NO production. The production of other representative mediators, such as tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), was also investigated to compare the structural requirements for the production of these cytokines with those for the production of NO. Structure-activity relationships in NO production correlated well with those in the production of TNF-α and IL-6. Among the lipid A analogues possessing different numbers of acyl groups on a 4-O-phosphono-d-glucosamine backbone, compounds like GLA-60 that possess three tetradecanoyl (C14) groups exhibited stronger activities in the production of the mediators than compounds possessing four or two C14 groups. Time course study of the production of these mediators showed that production of NO started and peaked later than those of TNF-α and IL-6. Neither neutralization of TNF-α activity by antibody nor suppression of TNF-α production by pentoxifylline showed a significant suppressive effect on production of NO and IL-6 upon stimulation with LPS or lipid A analogues. Neutralization of IL-6 activity by antibody showed no significant suppressive effect on production of NO and TNF-α. A monosaccharide lipid A analogue (GLA-58) which exhibited no detectable agonistic activity showed a suppressive effect on the production of all three mediators upon stimulation with LPS or lipid A analogues. These results indicate that signals for NO production by LPS agonists in murine macrophages are transduced in good correlation with those for production of TNF-α and IL-6, although they are not transduced via production of those cytokines.

Generation of Zebrafish Lines with New Gata1 Mutations and Their Characterization with a Novel In Vitro Colony-Forming Assay.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1336-1336
Author(s):  
Raman Sood ◽  
Linda Rivera ◽  
Jagman Chahal ◽  
Anthony Burnetti ◽  
Milton English ◽  
...  
Keyword(s):  
Conditioned Medium ◽  
Time Course ◽  
Genetic Modifier ◽  
Compound Heterozygous ◽  
Cdna Clones ◽  
Kidney Cells ◽  
Adult Kidney ◽  
Ideal System

Abstract Gata1 is a transcription factor critical for erythroid and megakaryocyte differentiation. We have shown previously that the lethal bloodless phenotype of the zebrafish mutant vlad tepes (vlt) is due to a nonsense mutation in gata1, suggesting that hematopoietic regulation is conserved between zebrafish and mammals. We have now generated fish with 2 novel missense mutations, T301K and K333R, identified by sequencing exons 5 and 6 in 1235 F1 fish derived from ENU-mutagenized males. Both mutations change conserved residues in the C-terminal zinc finger domain of gata1. Embryos homozygous for either T301K or K333R mutation showed normal circulation and survived to adulthood. Reduced hemoglobin levels were observed in T301K homozygous embryos compared to K333R homozygotes and wildtype by o-dianisidine staining. We crossed both mutations to vlt carrier fish and generated compound heterozygotes for further evaluation. T301K/vlt compound heterozygous embryos lacked circulation and hemoglobin staining, whereas K333R/vlt embryos had normal circulation and hemoglobin staining. These data suggest that the T301K mutation acts as a hypomorphic allele, having stronger phenotype in the presence of a null allele. Fish with both T301K/vlt and K333R/vlt genotypes survive to adulthood in expected Mendelian ratios. Time course observations show that T301K/vlt fish regain circulation around day 14, which is the time when most vlt/vlt fish die. These data suggest that during definitive hematopoiesis cells may be less sensitive to gata1 deficiency. In addition, we observed reduced number of circulating platelets in vlt/vlt embryos but normal in T301K/vlt embryos, suggesting that megakaryocyte maturation is regulated by gata1 in zebrafish. The in vitro culture of hematopoietic progenitors has been a powerful tool to study mammalian hematopoiesis, but similar techniques have not been available in the zebrafish. We hypothesized that the use of the zebrafish orthologs of Stem Cell Factor (scf) and Erythropoietin (epo) in semi soild medium would allow the growth and enumeration of colonies derived from zebrafish kidney cells. Based on homology to mammalian proteins, we identified zebrafish scf and epo cDNA clones (40.8% and 49.7% similarities to human SCF and EPO respectively), and expressed them in 293 cells. Methylcellulose medium containing conditioned medium from transfected cells was mixed with 105 to 106 adult kidney cells. No colonies developed in cultures with mock transfected 293 conditioned medium. In contrast, small erythroid colonies appeared between 2 to 6 days in cultures containing epo and/or scf conditioned medium. Larger erythroid colonies were detected in 8 to12 days. In the presence of scf, additional distinct colonies comprising of monocytes, neutrophils and/or erythroid cells were observed. Cultures of adult kidney cells from T301K/vlt and T301K/T301K fish showed 2–6 fold reduction (p=0.01 and 0.006 respectively) in the number of colonies. These results are consistent with the reduced number of hematopoietic cells observed in kidney sections of adult T301K homozygotes. In conclusion, we have generated gata1 mutant fish that revealed a conserved role of gata1 in zebrafish erythroid and megakaryocyte developments. The viable gata1 mutants and our novel in vitro differentiation system will be useful for studying the role of gata1 in adult hematopoiesis and in leukemogenesis. The mutants will also serve as an ideal system for genetic modifier screens.

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