The role of 20-hydroxyecdysone in stimulating epidermal mitoses during the laval-pupal transformation of the tobacco hornworm, Manduca sexta

Development ◽  
1987 ◽  
Vol 100 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Y. Kato ◽  
L.M. Riddiford
Keyword(s):  
Mitotic Index ◽  
Manduca Sexta ◽  
Ploidy Level ◽  
Polyploid Cells ◽  
Mitotic Frequency ◽  
Mitotic Figures ◽  
Dorsal Epidermis

Temporal and regional changes in mitotic frequency were examined in the dorsal epidermis of the fourth and fifth abdominal segments of Manduca sexta during metamorphosis. Mitoses occurred only in the middle intrasegmental region, but not in the segmental margins. The mitoses began early on day 5 and rose to maximum of 2á6–4á6% about 10h later. When the integument from day 4 (wandering) larvae was cultured in Grace's medium containing 0.3 to 1μgml-1 20-hydroxyecdysone (20HE), the mitotic index increased with a peak at 18–24h exposure approximately equal to that found in situ. The level of 20HE required to initiate mitoses was similar to that found in vivo during the beginning of the prepupal rise in ecdysteroid and therefore is likely to be the signal for these cells to decrease their ploidy level of 4–32C to 2–8C at this time. The polyploid cells had larger mitotic figures and required a longer exposure to 20-hydroxyecdysone to initiate mitosis. Some multipolar mitotic figures were observed.

The Role of Microbiology in Models of Dental Caries: Reaction Paper

1995 ◽  
Vol 9 (3) ◽  
pp. 255-269 ◽  
Author(s):  
G.H. Bowden
Keyword(s):  
Process Selection ◽  
Advantages And Disadvantages ◽  
Test Models ◽  
Plaque Development ◽  
In Vitro Systems ◽  
Selection Of

Models of the caries process have made significant contributions toward defining the roles of bacteria in caries. Microbiologists use a variety of in vitro systems to model aspects of the caries process. Also, in situ models in humans provide information on the microbiology of caries in vivo. These models do not involve the entire process leading to natural caries; consequently, the results from such studies are used to deduce the roles of bacteria in natural caries. Therefore, they can be described as Inferential Caries Models. In contrast, animal models and some clinical trials in humans involve natural caries and can be described as Complete Caries Models. Furthermore, these models are used in two distinct ways. They can be used as Exploratory Models to explore different aspects of the caries process, or as Test Models to determine the effects of anticaries agents. This dichotomy in approach to the use of caries models results in modification of the models to suit a particular role. For example, if we consider Exploratory Models, the in situ appliance in humans is superior to others for analyzing the microbiology of plaque development and demineralization in vivo. The chemostat and biofilm models are excellent for exploring factors influencing bacterial interactions. Both models can also be used as Test Models. The in situ model has been used to test the effects of fluoride on the microflora and demineralization, while the chemostat and biofilm models allow for the testing of antibacterial agents. Each model has its advantages and disadvantages and role in analysis of the caries process. Selection of the model depends on the scientific question posed and the limitations imposed by the conditions available for the study.

Carbonic anhydrase in the midgut of larvalAedes aegypti: cloning, localization and inhibition

2002 ◽  
Vol 205 (5) ◽  
pp. 591-602 ◽  
Author(s):  
Maria del Pilar Corena ◽  
Theresa J. Seron ◽  
Herm K. Lehman ◽  
Judith D. Ochrietor ◽  
Andrea Kohn ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Aedes Aegypti ◽  
Fruit Fly ◽  
Cellular Heterogeneity ◽  
Carbonic Anhydrases ◽  
Larval Midgut ◽  
Posterior Midgut

SUMMARYThe larval mosquito midgut exhibits one of the highest pH values known in a biological system. While the pH inside the posterior midgut and gastric caeca ranges between 7.0 and 8.0, the pH inside the anterior midgut is close to 11.0. Alkalization is likely to involve bicarbonate/carbonate ions. These ions are produced in vivo by the enzymatic action of carbonic anhydrase. The purpose of this study was to investigate the role of this enzyme in the alkalization mechanism, to establish its presence and localization in the midgut of larval Aedes aegypti and to clone and characterize its cDNA. Here, we report the physiological demonstration of the involvement of carbonic anhydrase in midgut alkalization. Histochemistry and in situ hybridization showed that the enzyme appears to be localized throughout the midgut, although preferentially in the gastric caeca and posterior regions with specific cellular heterogeneity. Furthermore, we report the cloning and localization of the first carbonic anhydrase from mosquito larval midgut. A cDNA clone from Aedes aegypti larval midgut revealed sequence homology to α-carbonic anhydrases from vertebrates. Bioinformatics indicates the presence of at least six carbonic anhydrases or closely related genes in the genome of another dipteran, the fruit fly Drosophila melanogaster. Molecular analyses suggest that the larval mosquito may also possess multiple forms.

scholarly journals AL355338 acts as an oncogenic lncRNA by interacting with protein ENO1 to regulate EGFR/AKT pathway in NSCLC

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qian Hua ◽  
Dongliang Wang ◽  
Lin Zhao ◽  
Zhihui Hong ◽  
Kairu Ni ◽  
...  
Keyword(s):  
Aerobic Glycolysis ◽  
Transcript Abundance ◽  
Metabolic Reprogramming ◽  
Clinical Samples ◽  
Abnormal Metabolism ◽  
Considerable Morbidity

Abstract Background Non-small cell lung cancer (NSCLC) is a malignancy with considerable morbidity and mortality. Abnormal metabolism is a hallmark of cancer; however, the mechanism of glycolysis regulation in NSCLC progression is not completely understood. Recent studies suggest that some dysregulated long non-coding RNAs (lncRNAs) play important roles in tumor metabolic reprogramming. Methods To identify glycolysis-associated-lncRNAs in NSCLC, we compared RNA-sequencing results between high 18F-fluorodeoxyglucose (FDG)-uptake NSCLC tissues and paired paratumor tissues. The transcript abundance of AL355338 in 80 pairs of clinical samples was evaluated by quantitative real-time PCR assay and fluorescence in situ hybridization. The biological role of AL355338 on NSCLC cells were evaluated by functional experiments in vitro and in vivo. Moreover, RNA pull-down, mass spectrometry and RNA immunoprecipitation (RIP) assays were used to identify the protein interacted with AL355338. Co-immunoprecipitation, in situ proximity ligation assays and western blotting were applied to define the potential downstream pathways of AL355338. Results AL355338 was an upregulated glycolysis-associated lncRNA in NSCLC. Functional assays revealed that AL355338 was critical for promoting aerobic glycolysis and NSCLC progression. Mechanistic investigations showed that AL355338 directly bound with alpha-enolase (ENO1) and enhanced the protein’s stability by modulating its degradation and ubiquitination. A positive correlation was observed between AL355338 and ENO1 in NSCLC, and ENO1 was subsequently confirmed to be responsible for the oncogenic role of AL355338. Furthermore, AL355338 was capable of modulating ENO1/EGFR complex interaction and further activating EGFR-AKT signaling. Conclusions This study indicates that AL355338 confers an aggressive phenotype to NSCLC, and targeting it might be an effective therapeutic strategy.

scholarly journals LncRNA-URHC Functions as a ceRNA to Regulate Danjb9 Expression by Competitively Binding to miR-5007-3p in Hepatocellular Carcinoma

2021 ◽  
Author(s):  
kunwei niu ◽  
Shibin Qu ◽  
Xuan Zhang ◽  
Jimin Dai ◽  
Jianlin Wang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Biological Effects ◽  
Luciferase Reporter ◽  
Underlying Mechanisms ◽  
Proliferation In Vitro ◽  
Hcc Cells

Abstract Background: Hepatocellular carcinoma (HCC) is often diagnosed at a late stage, when the prognosis is poor. The regulation of long non-coding RNAs (lncRNAs) plays a crucial role in HCC. However, the precise regulatory mechanisms of lncRNA signaling in HCC remain largely unknown. We study aim to investigate the underlying mechanisms of lncRNA (upregulated in hepatocellular carcinoma) URHC in HCC. Methods: RT-qPCR, fluorescence in situ hybridization (FISH) staining, EdU, colony formation, and tumor xenografts experiments were used to identify localized and biological effects of URHC on HCC cells in vitro and in vivo. The bioinformatics analysis, Dual-luciferase reporter assay, and rescue experiments revealed the potential mechanism of URHC.Results: URHC silencing may inhibit the HCC cells proliferation in vitro and in vivo. We found that URHC was mainly localized in the cytoplasm. The expression of miR-5007-3p was negatively regulated by URHC. And miR-5007-3p could reverse the effect of URHC in HCC cells. The expression of DNAJB9 was negatively regulated by miR-5007-3p but positively regulated by URHC. These suggesting of lncRNA-URHC positively regulated the level of DNAJB9 by sponging miR-5007-3p.Conclusion: Together, our study elucidated the role of URHC as a miRNA sponge in HCC, and shed new light on lncRNA-directed diagnostics and therapeutics in HCC.

Cytoarchitecture of the Xenopus thymus following gamma-irradiation

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 95-105
Author(s):  
JH Russ ◽  
JD Horton
Keyword(s):  
Gamma Irradiation ◽  
Tolerance Induction ◽  
Cell Types ◽  
Whole Body ◽  
Thymic Stromal Cells ◽  
Normal Architecture

This paper describes in vitro and in vivo attempts to deplete the 4- to 8-month-old Xenopus laevis (J strain) thymus of its lymphocyte compartment. Gamma irradiation (2-3000 rad) of the excised thymus, followed by two weeks in organ culture, is effective in removing lymphocytes, but causes drastic reduction in size and loss of normal architecture. In contrast, in vivo whole-body irradiation (3000 rad) and subsequent in situ residence for 8-14 days proves successful in providing a lymphocyte-depleted froglet thymus without loss of cortical and medullary zones. In vivo-irradiated thymuses are about half normal size, lack cortical lymphocytes, but still retain some medullary thymocytes; they show no signs of lymphocyte regeneration when subsequently organ cultured for 2 weeks. Light microscopy of 1 micron, plastic-embedded sections and electron microscopy reveal that a range of thymic stromal cell types are retained and that increased numbers of cysts, mucous and myoid cells are found in the thymus following whole-body irradiation. In vivo-irradiated thymuses are therefore suitable for implantation studies exploring the role of thymic stromal cells in tolerance induction of differentiating T lymphocytes.

scholarly journals Pontine respiratory activity involved in inspiratory/expiratory phase transition

2009 ◽  
Vol 364 (1529) ◽  
pp. 2517-2526 ◽  
Author(s):  
Michael Mörschel ◽  
Mathias Dutschmann
Keyword(s):  
Phase Transition ◽  
Sensory Feedback ◽  
Respiratory Pattern ◽  
Respiratory Neurons ◽  
Related Activity ◽  
Lung Inflation ◽  
Pulmonary Stretch Receptors

Control of the timing of the inspiratory/expiratory (IE) phase transition is a hallmark of respiratory pattern formation. In principle, sensory feedback from pulmonary stretch receptors (Breuer–Hering reflex, BHR) is seen as the major controller for the IE phase transition, while pontine-based control of IE phase transition by both the pontine Kölliker–Fuse nucleus (KF) and parabrachial complex is seen as a secondary or backup mechanism. However, previous studies have shown that the BHR can habituate in vivo . Thus, habituation reduces sensory feedback, so the role of the pons, and specifically the KF, for IE phase transition may increase dramatically. Pontine-mediated control of the IE phase transition is not completely understood. In the present review, we discuss existing models for ponto-medullary interaction that may be involved in the control of inspiratory duration and IE transition. We also present intracellular recordings of pontine respiratory units derived from an in situ intra-arterially perfused brainstem preparation of rats. With the absence of lung inflation, this preparation generates a normal respiratory pattern and many of the recorded pontine units demonstrated phasic respiratory-related activity. The analysis of changes in membrane potentials of pontine respiratory neurons has allowed us to propose a number of pontine-medullary interactions not considered before. The involvement of these putative interactions in pontine-mediated control of IE phase transitions is discussed.

scholarly journals LncRNA AC245100.4 binds HSP90 to promote the proliferation of prostate cancer

Epigenomics ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 1257-1271
Author(s):  
Rongjun Cui ◽  
Chi Liu ◽  
Ping Lin ◽  
Hui Xie ◽  
Wei Wang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Counting ◽  
Chaperone Function ◽  
In Vivo Assays ◽  
Iκb Kinase ◽  
Rna Immunoprecipitation ◽  
The Stability

Aim: To investigate the role and mechanisms of AC245100.4 in prostate cancer. Materials & methods: The expression and location of AC245100.4 were examined using real-time PCR and  in situ hybridization. Cell Counting Kit-8, clone formation, flow cytometry and in vivo assays were conducted to determine the role of AC245100.4. RNA antisense purification with mass spectrometry and RNA immunoprecipitation were performed to identify proteins that bind to AC245100.4. Western blotting was performed to quantify the expression of protein. Results: AC245100.4 expression was upregulated in prostate cancer and mainly located in the cytoplasm. Knockdown of AC245100.4 inhibited proliferation of prostate cancer. Mechanistically, AC245100.4 bound to HSP90 and altered its chaperone function, increased the stability of IκB kinase and activated the NFκB signaling pathway. Conclusion: AC245100.4 promotes the proliferation of prostate cancer via binding of HSP90.

Oxygen supply and oxidative phosphorylation limitation in rat myocardium in situ

2001 ◽  
Vol 280 (5) ◽  
pp. H2030-H2037 ◽  
Author(s):  
Ulrike Kreutzer ◽  
Yousry Mekhamer ◽  
Youngran Chung ◽  
Thomas Jue
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Coronary Flow ◽  
Rate Pressure Product ◽  
Rat Myocardium ◽  
H Nmr ◽  
Open Question ◽  
Primary Substrate

The 1H-NMR signal of the proximal histidyl-NδH of deoxymyoglobin is detectable in the in situ rat myocardium and can reflect the intracellular Po 2. Under basal normoxic conditions, the cellular Po 2 is sufficient to saturate myoglobin (Mb). No proximal histidyl signal of Mb is detectable. On ligation of the left anterior descending coronary artery, the Mb signal at 78 parts/million (ppm) appears, along with a peak shoulder assigned to the corresponding signal of Hb. During dopamine infusion up to 80 μg · kg−1 · min−1, both the heart rate-pressure product (RPP) and myocardial oxygen consumption (MV˙o 2) increase by about a factor of 2. Coronary flow increases by 84%, and O2extraction (arteriovenous O2 difference) rises by 31%. Despite the increased respiration and work, no deoxymyoglobin signal is detected, implying that the intracellular O2 level still saturates MbO2, well above the Po 2at 50% saturation of Mb. The phosphocreatine (PCr) level decreases, however, during dopamine stimulation, and the ratio of the change in Pi over PCr (ΔPi/PCr) increases by 0.19. Infusion of either pyruvate, as the primary substrate, or dichloroacetate, a pyruvate dehydrogenase activator, abolishes the change in ΔPi/PCr. Intracellular O2 supply does not limit MV˙o 2, and the role of ADP in regulating respiration in rat myocardium in vivo remains an open question.

The role of phosphatidylcholine in fatty acid exchange and desaturation in Brassica napus L. leaves

2000 ◽  
Vol 349 (1) ◽  
pp. 127-133 ◽  
Author(s):  
John P. WILLIAMS ◽  
Valerie IMPERIAL ◽  
Mobashsher U. KHAN ◽  
Joanna N. HODSON
Keyword(s):  
Fatty Acid ◽  
Brassica Napus ◽  
Unsaturated Fatty Acid ◽  
Brassica Napus L ◽  
14C Labelling ◽  
High Level ◽  
Acid Exchange

The role of phosphatidylcholine (PC) in fatty acid exchange and desaturation was examined and compared with that of monogalactosyldiacylglycerol (MGDG) in Brassica napus leaves using 14C-labelling in vivo. Data are presented which indicate that in the chloroplast newly formed saturated (palmitic acid, 16:0) and monounsaturated (oleic acid, 18:1) fatty acid is incorporated into MGDG and desaturated in situ. In the non-plastidic compartments, however, newly formed fatty acid is exchanged with polyunsaturated fatty acid in PC, the probable major site of subsequent desaturation. The unsaturated fatty acid is released to the acyl-CoA pool, which is then used to synthesize diacylglycerol (DAG) containing a high level of unsaturated fatty acid. This highly unsaturated DAG may be the source for the biosynthesis of other cellular glycerolipids. The generally accepted pathway in which PC is synthesized from molecular species of DAG containing 16:0 and 18:1 followed by desaturation of the 18:1 to linoleic (18:2) and linolenic (18:3) acids is questioned.

scholarly journals Influence of condensation domains on activity and specificity of adenylation domains

2021 ◽  
Author(s):  
Janik Kranz ◽  
Sebastian L. Wenski ◽  
Alexnder A. Dichter ◽  
Helge B. Bode ◽  
Kenan A. J. Bozhueyuek
Keyword(s):  
Structural Features ◽  
Peptide Synthetases ◽  
In Situ Experiments ◽  
The Subject ◽  
New Perspective ◽  
Condensation Domain

Many clinically used natural products are produced by non-ribosomal peptide synthetases (NRPSs), which due to their modular nature should be accessible to modification and engineering approaches. While the adenylation domain (A) plays the key role in substrate recognition and activation, the condensation domain (C) which is responsible for substrate linkage and stereochemical filtering recently became the subject of debate - with its attributed role as a "gatekeeper" being called into question. Since we have thoroughly investigated different combinations of C-A didomains in a series of in vitro, in vivo, and in situ experiments suggesting an important role to the C-A interface for the activity and specificity of the downstream A domain and not the C domain as such, we would like to contribute to this discussion. The role of the C-A interface, termed 'extended gatekeeping', due to structural features of the C domains, can also be transferred to other NRPSs by engineering, was finally investigated and characterised in an in silico approach on 30 wild-type and recombinant C-A interfaces. With these data, we not only would like to offer a new perspective on the specificity of C domains, but also to revise our previously established NRPS engineering and construction rules.

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