Role of the gut proteinases from mosquito larvae in the mechanism of action and the specificity of the Bacillus sphaericus toxin

1990 ◽  
Vol 36 (11) ◽  
pp. 804-807 ◽  
Author(s):  
Luc Nicolas ◽  
Anne Lecroisey ◽  
Jean-François Charles
Keyword(s):  
Cell Cultures ◽  
Spodoptera Littoralis ◽  
Mosquito Species ◽  
Bacillus Sphaericus ◽  
Cellular Level ◽  
Mosquito Cell ◽  
Mosquito Larvae

Gut proteinases from larvae of mosquito species both susceptible and not susceptible to Bacillus sphaericus converted the 43-kDa toxin to a 40-kDa polypeptide exhibiting enhanced cytotoxicity to mosquito cell cultures. The toxin was also activated by gut proteinases from the nonsusceptible Lepidoptera Spodoptera littoralis in vitro and in vivo. Therefore, the specificity of Bacillus sphaericus toxin does not seem to be determined by gut proteinase action. However, susceptibility of mosquito cell cultures did not reflect the specificity of the toxin, which must now be investigated at the cellular level in the larvae. Key words: mosquitoes, Bacillus sphaericus, bacterial toxins, proteinases, specificity.

scholarly journals Estrogen receptors and estetrol-dependent neuroprotective actions: a pilot study

2017 ◽  
Vol 232 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Ekaterine Tskitishvili ◽  
Christel Pequeux ◽  
Carine Munaut ◽  
Renaud Viellevoye ◽  
Michelle Nisolle ◽  
...  
Keyword(s):  
Estrogen Receptors ◽  
Cell Survival ◽  
Cell Cultures ◽  
Damage Model ◽  
Neuronal Cell ◽  
Concomitant Treatment ◽  
Ldh Activity

Estetrol (E4) has strong antioxidative, neurogenic and angiogenic effects in neural system resulting in the attenuation of neonatal hypoxic–ischemic encephalopathy. We aimed to define the role of estrogen receptors in E4-dependent actions in neuronal cell cultures and prove the promyelinating effect of E4. In vitro the antioxidative and cell survival/proliferating effects of E4 on H2O2-induced oxidative stress in primary hippocampal cell cultures were studied using different combinations of specific inhibitors for ERα (MPP dihydrochloride), ERβ (PHTTP), GPR30 (G15) and palmytoilation (2-BR). LDH activity and cell survival assays were performed. In vivo the promyelinating role of different concentrations of E4 (1 mg/kg/day, 5 mg/kg/day, 10 mg/kg/day, 50 mg/kg/day) was investigated using the hypoxic–ischemic brain damage model in the 7-day-old immature rats before/after the induction of hypoxic–ischemic insult. Myelin basic protein (MBP) immunostaining was performed on brain coronal sections. Our results show that LDH activity is significantly upregulated in cell cultures where the E4’s effect was completely blocked by concomitant treatment either with ERα and ERβ inhibitors (MPP and PHTPP, respectively), or ERα and ERβ inhibitors combined with 2-BR. Cell survival is significantly downregulated in cell cultures where the effect of E4 was blocked by ERβ inhibitor (PHTTP) alone. The blockage of GRP30 receptor did affect neither LDH activity nor cell survival. MBP immunostaining is significantly upregulated in E4-pretreated groups at a concentration of 5 mg/kg/day and 50 mg/kg/day E4, whereas the MBP-positive area OD ratio is significantly increased in all the E4-treated groups. E4’s antioxidative actions mostly depend on ERα and ERβ, whereas neurogenesis and possibly promyelinating activities might be realized through ERβ.

scholarly journals A 3D Model of Human Trabecular Meshwork for the Research Study of Glaucoma

2020 ◽  
Vol 11 ◽  
Author(s):  
Sara Tirendi ◽  
Sergio Claudio Saccà ◽  
Stefania Vernazza ◽  
Carlo Traverso ◽  
Anna Maria Bassi ◽  
...  
Keyword(s):  
Animal Models ◽  
Trabecular Meshwork ◽  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Cellular Level ◽  
Research Progress ◽  
New Therapeutic Approaches

Glaucoma is a multifactorial syndrome in which the development of pro-apoptotic signals are the causes for retinal ganglion cell (RGC) loss. Most of the research progress in the glaucoma field have been based on experimentally inducible glaucoma animal models, which provided results about RGC loss after either the crash of the optic nerve or IOP elevation. In addition, there are genetically modified mouse models (DBA/2J), which make the study of hereditary forms of glaucoma possible. However, these approaches have not been able to identify all the molecular mechanisms characterizing glaucoma, possibly due to the disadvantages and limits related to the use of animals. In fact, the results obtained with small animals (i.e., rodents), which are the most commonly used, are often not aligned with human conditions due to their low degree of similarity with the human eye anatomy. Although the results obtained from non-human primates are in line with human conditions, they are little used for the study of glaucoma and its outcomes at cellular level due to their costs and their poor ease of handling. In this regard, according to at least two of the 3Rs principles, there is a need for reliable human-based in vitro models to better clarify the mechanisms involved in disease progression, and possibly to broaden the scope of the results so far obtained with animal models. The proper selection of an in vitro model with a “closer to in vivo” microenvironment and structure, for instance, allows for the identification of the biomarkers involved in the early stages of glaucoma and contributes to the development of new therapeutic approaches. This review summarizes the most recent findings in the glaucoma field through the use of human two- and three-dimensional cultures. In particular, it focuses on the role of the scaffold and the use of bioreactors in preserving the physiological relevance of in vivo conditions of the human trabecular meshwork cells in three-dimensional cultures. Moreover, data from these studies also highlight the pivotal role of oxidative stress in promoting the production of trabecular meshwork-derived pro-apoptotic signals, which are one of the first marks of trabecular meshwork damage. The resulting loss of barrier function, increase of intraocular pressure, as well the promotion of neuroinflammation and neurodegeneration are listed as the main features of glaucoma. Therefore, a better understanding of the first molecular events, which trigger the glaucoma cascade, allows the identification of new targets for an early neuroprotective therapeutic approach.

scholarly journals Mitochondrial Genome Regulator TFAM Modulates Head and Neck Tumorigenesis Through Activation of Intracellular Metabolic Reprogramming and Oncogenic Effectors

2020 ◽  
Author(s):  
Yi-Ta Hsieh ◽  
Hsi-Feng Tu ◽  
Muh-Hwa Yang ◽  
Yi-Fen Chen ◽  
Chien-Ling Huang ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Head And Neck ◽  
Aerobic Glycolysis ◽  
Survival Rates ◽  
Cellular Level ◽  
Metabolic Reprogramming ◽  
Clinical Databases

Abstract Background: Mitochondrial defect is often observed in cancers while, in comparison with other metabolic cues, mitochondria mediated regulations in controlling tumorigenesis are less emphasized. Mitochondrial transcriptional factor A (TFAM) acts as a key regulatory factor to control mitochondrial DNA (mtDNA) replication and packing; the role of TFAM in modulating carcinogenesis, however, is controversial. Current study therefore aims to define TFAM mediated regulations in head and neck cancer (HNC) development. Methods: Multifaceted analyses in HNC cells genetically manipulated for TFAM were performed. Clinical correlations of TFAM and its downstream Electron Transport Chain (ETC) associated factors in regulating HNC progression were also examined in HNC specimens and different clinical databasesResults: At the cellular level, it was demonstrated that shRNA mediated TFAM silencing resulted in an enhanced cell proliferation, both in vitro and in vivo; in contrast, TFAM overexpression suppressed cell growth. Moreover, TFAM loss also facilitated cell migration and chemodrug resistance. At the molecular basis, TFAM mediated phenotypic changes could be resulting from metabolic reprogramming by directing HNC metabolism towards aerobic glycolysis, based on the detection of less respiratory capacity in accompany with greater extracellular acidification in response to TFAM loss. Interestingly, it was also found that TFAM loss upregulated ERK1/2 and Akt-mTORC-S6 signaling activity, revealing a potential "mitochondrion-to-cytoplasm" retrograde regulatory cue in controlling HNC malignancy. Clinical impact of TFAM and its downstream targets was further examined in clinical HNC tissues while the results showed that TFAM expression and mtDNA copy numbers were significant dropped in HNC tissues compared with their normal counterparts. By using clinical databases, HNC subjects with higher TFAM expression and less genetic alteration(s) exhibited better survival rates. Conclusion: Collectively, Current study uncovered a tumor suppressing role of TFAM and mitochondrial genome in determining HNC oncogenicity. This TFAM mediated regualtions are through intracellular metabolic reprogramming and mitochondria-to-cytoplasm cross-talk to activate oncogenic signals.

scholarly journals Inhibition of Autophagy In Vivo Extends Methamphetamine Toxicity to Mesencephalic Cell Bodies

2021 ◽  
Vol 14 (10) ◽  
pp. 1003
Author(s):  
Michela Ferrucci ◽  
Francesca Biagioni ◽  
Carla L. Busceti ◽  
Chiara Vidoni ◽  
Roberta Castino ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Ventral Tegmental Area ◽  
Cell Cultures ◽  
Substantia Nigra Pars Compacta ◽  
Systemic Injection ◽  
Axon Terminals ◽  
Nigrostriatal Dopamine

Methamphetamine (METH) is a widely abused psychostimulant and a stress-inducing compound, which leads to neurotoxicity for nigrostriatal dopamine (DA) terminals in rodents and primates including humans. In vitro studies indicate that autophagy is a strong modulator of METH toxicity. In detail, suppressing autophagy increases METH toxicity, while stimulating autophagy prevents METH-induced toxicity in cell cultures. In the present study, the role of autophagy was investigated in vivo. In the whole brain, METH alone destroys meso-striatal DA axon terminals, while fairly sparing DA cell bodies within substantia nigra pars compacta (SNpc). No damage to either cell bodies or axons from ventral tegmental area (VTA) is currently documented. According to the hypothesis that ongoing autophagy prevents METH-induced DA toxicity, we tested whether systemic injection of autophagy inhibitors such as asparagine (ASN, 1000 mg/Kg) or glutamine (GLN, 1000 mg/Kg), may extend METH toxicity to DA cell bodies, both within SNpc and VTA, where autophagy was found to be inhibited. When METH (5 mg/Kg × 4, 2 h apart) was administered to C57Bl/6 mice following ASN or GLN, a frank loss of cell bodies takes place within SNpc and a loss of both axons and cell bodies of VTA neurons is documented. These data indicate that, ongoing autophagy protects DA neurons and determines the refractoriness of cell bodies to METH-induced toxicity.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Anti-obesity role of Aster glehni extract: in vivo and in vitro effects

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
HM Lee ◽  
TG Ahn ◽  
CW Kim ◽  
HJ An
Keyword(s):  
In Vitro Effects

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

THYROID STIMULATORS AND THYROID STIMULATION

1971 ◽  
Vol 66 (3) ◽  
pp. 558-576 ◽  
Author(s):  
Gerald Burke
Keyword(s):  
Regulatory System ◽  
Control Site ◽  
Thyroid Cell ◽  
Primary Control ◽  
Physico Chemical ◽  
Site Of Action ◽  
Long Acting

ABSTRACT A long-acting thyroid stimulator (LATS), distinct from pituitary thyrotrophin (TSH), is found in the serum of some patients with Graves' disease. Despite the marked physico-chemical and immunologic differences between the two stimulators, both in vivo and in vitro studies indicate that LATS and TSH act on the same thyroidal site(s) and that such stimulation does not require penetration of the thyroid cell. Although resorption of colloid and secretion of thyroid hormone are early responses to both TSH and LATS, available evidence reveals no basic metabolic pathway which must be activated by these hormones in order for iodination reactions to occur. Cyclic 3′, 5′-AMP appears to mediate TSH and LATS effects on iodination reactions but the role of this compound in activating thyroidal intermediary metabolism is less clear. Based on the evidence reviewed herein, it is suggested that the primary site of action of thyroid stimulators is at the cell membrane and that beyond the(se) primary control site(s), there exists a multifaceted regulatory system for thyroid hormonogenesis and cell growth.

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