scholarly journals Novel cholinesterase paralogs of Schistosoma mansoni have perceived roles in cholinergic signaling, glucose scavenging and drug detoxification and are essential for parasite survival

2019 ◽  
Author(s):  
Bemnet Tedla ◽  
Javier Sotillo ◽  
Darren Pickering ◽  
Ramon M. Eichenberger ◽  
Luke Becker ◽  
...  
Keyword(s):  
Developmental Expression ◽  
Laboratory Animals ◽  
Parasite Development ◽  
Ache Inhibitor ◽  
Ache Inhibitors ◽  
Cholinergic Signaling ◽  
Parasite Survival ◽  
Drug Detoxification

AbstractCholinesterase (ChE) function in schistosomes is essential for orchestration of parasite neurotransmission but has been poorly defined with respect to the molecules responsible. Interrogation of the S. mansoni genome has revealed the presence of three ChE domain-containing genes (Smche)s, which we have shown to encode two functional acetylcholinesterases (AChE)s (Smache1 – smp_154600 and Smache3 – smp_136690) and a butyrylcholinesterase (BChE) (Smbche1 – smp_125350). Antibodies to recombinant forms of each SmChE localized the proteins to the tegument and neuromusculature of adults and schistosomula and developmental expression profiling differed among the three molecules, suggestive of functions extending beyond traditional cholinergic signaling. For the first time in schistosomes, we identified ChE enzymatic activity in fluke excretory/secretory (ES) products and, using proteomic approaches, attributed this activity to the presence of SmAChE1 and SmBChE1. To address the hypothesis that tegumental AChE mediates exogenous glucose scavenging by the parasite, we show that RNAi-mediated knockdown of smache1 and smache3, but not smbche1, significantly reduces glucose uptake by schistosomes. Parasite survival in vitro and in vivo was significantly impaired by silencing of each smche, either individually or in combination, attesting to the essential roles of these molecules. Lastly, in the first characterization study of a BChE from helminths, evidence is provided that SmBChE1 may act as a bio-scavenger of AChE inhibitors as the addition of recombinant SmBChE1 to parasite cultures mitigated the effect of the anti-schistosome AChE inhibitor DDVP (DDVP), whereas smbche1-silenced parasites displayed increased sensitivity to DDVP.Author summaryCholinesterases - aceytlcholinesterases (AChE)s and butyrylcholinesterases (BChE)s - are multi-functional enzymes that play a pivotal role in the nervous system of parasites by regulating neurotransmission through acetylcholine hydrolysis. Herein, we provide a detailed characterization of schistosome cholinesterases using molecular, enzymatic and gene-silencing approaches and show evidence for these molecules having roles in glucose scavenging and drug detoxification, in addition to their neuronal function. Further, we demonstrate the importance of these proteins to parasite development and survival through gene knockdown experiments in laboratory animals, providing evidence for the use of these proteins in the development of novel intervention strategies against schistosomiasis.

Neurotoxicity of Pesticides: The Roadmap for the Cubic Mode of Action

2020 ◽  
Vol 27 (1) ◽  
pp. 54-77 ◽  
Author(s):  
Bogdan Bumbăcilă ◽  
Mihai V. Putz
Keyword(s):  
Biological Activity ◽  
Wiener Index ◽  
Laboratory Animals ◽  
Covalent Bonds ◽  
Organophosphate Compounds ◽  
Sar Studies ◽  
Structure Activity ◽  
Cubic Structure

Pesticides are used today on a planetary-wide scale. The rising need for substances with this biological activity due to an increasing consumption of agricultural and animal products and to the development of urban areas makes the chemical industry to constantly investigate new molecules or to improve the physicochemical characteristics, increase the biological activities and improve the toxicity profiles of the already known ones. Molecular databases are increasingly accessible for in vitro and in vivo bioavailability studies. In this context, structure-activity studies, by their in silico - in cerebro methods, are used to precede in vitro and in vivo studies in plants and experimental animals because they can indicate trends by statistical methods or biological activity models expressed as mathematical equations or graphical correlations, so a direction of study can be developed or another can be abandoned, saving financial resources, time and laboratory animals. Following this line of research the present paper reviews the Structure-Activity Relationship (SAR) studies and proposes a correlation between a topological connectivity index and the biological activity or toxicity made as a result of a study performed on 11 molecules of organophosphate compounds, randomly chosen, with a basic structure including a Phosphorus atom double bounded to an Oxygen atom or to a Sulfur one and having three other simple covalent bonds with two alkoxy (-methoxy or -ethoxy) groups and to another functional group different from the alkoxy groups. The molecules were packed on a cubic structure consisting of three adjacent cubes, respecting a principle of topological efficiency, that of occupying a minimal space in that cubic structure, a method that was called the Clef Method. The central topological index selected for correlation was the Wiener index, since it was possible this way to discuss different adjacencies between the nodes in the graphs corresponding to the organophosphate compounds molecules packed on the cubic structure; accordingly, "three dimensional" variants of these connectivity indices could be considered and further used for studying the qualitative-quantitative relationships for the specific molecule-enzyme interaction complexes, including correlation between the Wiener weights (nodal specific contributions to the total Wiener index of the molecular graph) and the biochemical reactivity of some of the atoms. Finally, when passing from SAR to Q(uantitative)-SAR studies, especially by the present advanced method of the cubic molecule (Clef Method) and its good assessment of the (neuro)toxicity of the studied molecules and of their inhibitory effect on the target enzyme - acetylcholinesterase, it can be seen that a predictability of the toxicity and activity of different analogue compounds can be ensured, facilitating the in vivo experiments or improving the usage of pesticides.

scholarly journals Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro

Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Antimalarial Activity ◽  
Clinical Malaria ◽  
Inhibitory Effect ◽  
Parasite Development ◽  
And Control ◽  
Speed Of Onset

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.

scholarly journals Indirect cholinergic activation slows down pancreatic cancer growth and tumor-associated inflammation

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Paulo L. Pfitzinger ◽  
Laura Fangmann ◽  
Kun Wang ◽  
Elke Demir ◽  
Engin Gürlevik ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Mouse Model ◽  
Tumor Stage ◽  
Ache Inhibitors ◽  
Impact On Survival ◽  
The Impact ◽  
Ache Expression ◽  
Cholinergic Activation

Abstract Background Nerve-cancer interactions are increasingly recognized to be of paramount importance for the emergence and progression of pancreatic cancer (PCa). Here, we investigated the role of indirect cholinergic activation on PCa progression through inhibition of acetylcholinesterase (AChE) via clinically available AChE-inhibitors, i.e. physostigmine and pyridostigmine. Methods We applied immunohistochemistry, immunoblotting, MTT-viability, invasion, flow-cytometric-cell-cycle-assays, phospho-kinase arrays, multiplex ELISA and xenografted mice to assess the impact of AChE inhibition on PCa cell growth and invasiveness, and tumor-associated inflammation. Survival analyses were performed in a novel genetically-induced, surgically-resectable mouse model of PCa under adjuvant treatment with gemcitabine+/−physostigmine/pyridostigmine (n = 30 mice). Human PCa specimens (n = 39) were analyzed for the impact of cancer AChE expression on tumor stage and survival. Results We discovered a strong expression of AChE in cancer cells of human PCa specimens. Inhibition of this cancer-cell-intrinsic AChE via pyridostigmine and physostigmine, or administration of acetylcholine (ACh), diminished PCa cell viability and invasion in vitro and in vivo via suppression of pERK signaling, and reduced tumor-associated macrophage (TAM) infiltration and serum pro-inflammatory cytokine levels. In the novel genetically-induced, surgically-resectable PCa mouse model, adjuvant co-therapy with AChE blockers had no impact on survival. Accordingly, survival of resected PCa patients did not differ based on tumor AChE expression levels. Patients with higher-stage PCa also exhibited loss of the ACh-synthesizing enzyme, choline-acetyltransferase (ChAT), in their nerves. Conclusion For future clinical trials of PCa, direct cholinergic stimulation of the muscarinic signaling, rather than indirect activation via AChE blockade, may be a more effective strategy.

Delimiting regulatory sequences of the Drosophila melanogaster Ddc gene

1986 ◽  
Vol 6 (12) ◽  
pp. 4548-4557
Author(s):  
J Hirsh ◽  
B A Morgan ◽  
S B Scholnick
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Line ◽  
Regulatory Elements ◽  
P Element ◽  
Developmental Expression ◽  
Upstream Region ◽  
Regulatory Sequences ◽  
Flanking Sequences

We delimited sequences necessary for in vivo expression of the Drosophila melanogaster dopa decarboxylase gene Ddc. The expression of in vitro-altered genes was assayed following germ line integration via P-element vectors. Sequences between -209 and -24 were necessary for normally regulated expression, although genes lacking these sequences could be expressed at 10 to 50% of wild-type levels at specific developmental times. These genes showed components of normal developmental expression, which suggests that they retain some regulatory elements. All Ddc genes lacking the normal immediate 5'-flanking sequences were grossly deficient in larval central nervous system expression. Thus, this upstream region must contain at least one element necessary for this expression. A mutated Ddc gene without a normal TATA boxlike sequence used the normal RNA start points, indicating that this sequences is not required for start point specificity.

The potential reproductive effects of exposure of domestic ruminants to endocrine disrupting compounds

2002 ◽  
Vol 74 (1) ◽  
pp. 3-12 ◽  
Author(s):  
M.L. Boerjan ◽  
S. Freijnagel ◽  
S.M. Rhind ◽  
G.A.L. Meijer
Keyword(s):  
Drinking Water ◽  
Reproductive Function ◽  
Endocrine Disrupting Compounds ◽  
Laboratory Animals ◽  
Domestic Ruminants ◽  
Reproductive Effects ◽  
Endocrine Disrupting ◽  
Contaminated Food

AbstractChemical compounds that mimic or block some of the actions of the steroid hormone oestradiol, have created public concern primarily because of potential adverse reproductive effects in wildlife and humans. Many studies, in vivo and in vitro, have revealed abnormal reproductive function following exposure to these compounds. The number of chemicals known to have the potential to modulate endocrine functions is increasing. In contrast to humans and wildlife, the potential reproductive effects of exposure of domestic animals to endocrine disrupting compounds (EDC) have been studied little. The aim of this overview is to evaluate the possible contribution of EDC to reproductive failure in domestic ruminants.Sources and classes of EDC are discussed as well as their structure and the modes of hormone disruption. Endocrine disrupting agents may interfere with the reproductive processes of both males and females at several points of the reproductive cycle and through a range of physiological mechanisms. Extrapolating from the results obtained with laboratory animals, the mechanisms whereby infertility in domestic ruminants might be expressed by exposure to EDC through contaminated food and drinking water are addressed.A preliminary risk assessment is included and it is concluded that under certain circumstances there may be a significantly enhanced intake of oestrogenic hormones and EDC through sewage-contaminated water or soil-contaminated herbage. The physiological consequences for domestic ruminants of EDC ingestion, at the rates estimated, are largely unknown. However, the levels of exposure to oestrogenic hormones and phthalates in grazing ruminants are such that when studying fertility problems in high-yielding dairy cattle the impacts of exposure to endocrine disruptors via the food and drinking water cannot be neglected.

scholarly journals Ex VivoMaturation Assay for Testing Antimalarial Sensitivity of Rodent Malaria Parasites

2016 ◽  
Vol 60 (11) ◽  
pp. 6859-6866 ◽  
Author(s):  
Zi Wei Chang ◽  
Benoit Malleret ◽  
Bruce Russell ◽  
Laurent Rénia ◽  
Carla Claser
Keyword(s):  
Ex Vivo ◽  
Single Step ◽  
Parasite Development ◽  
Ring Stage ◽  
Malaria Parasites ◽  
Rodent Malaria ◽  
Content Type ◽  
Parasite Biology

ABSTRACTEx vivoassay systems provide a powerful approach to studying human malaria parasite biology and to testing antimalarials. For rodent malaria parasites, short-termin vitroculture andex vivoantimalarial susceptibility assays are relatively cumbersome, relying onin vivopassage for synchronization, since ring-stage parasites are an essential starting material. Here, we describe a new approach based on the enrichment of ring-stagePlasmodium berghei,P. yoelii, andP. vinckei vinckeiusing a single-step Percoll gradient. Importantly, we demonstrate that the enriched ring-stage parasites develop synchronously regardless of the parasite strain or species used. Using a flow cytometry assay with Hoechst and ethidium or MitoTracker dye, we show that parasite development is easily and rapidly monitored. Finally, we demonstrate that this approach can be used to screen antimalarial drugs.

scholarly journals In vitro immunization approach to generate specific murine monoclonal IgG antibodies

2020 ◽  
Author(s):  
Sophia Michelchen ◽  
Burkhard Micheel ◽  
Katja Hanack
Keyword(s):  
Monoclonal Antibodies ◽  
Legionella Pneumophila ◽  
B Lymphocyte ◽  
Laboratory Animals ◽  
Igg Antibody ◽  
Simplified Approach ◽  
Humoral Immune ◽  
Viral Coat

AbstractGenerating monoclonal antibodies to date is a time intense process requiring immunization of laboratory animals. The transfer of the humoral immune response into in vitro settings shortens this process and circumvents the necessity of animal immunization. However, orchestrating the complex interplay of immune cells in vitro is very challenging. We aimed for a simplified approach focusing on the protagonist of antibody production: the B lymphocyte. We activated purified murine B lymphocytes in vitro with combinations of antigen and stimuli. Within ten days of culture we induced specific IgM and IgG antibody responses against a viral coat protein. Permanently antibody-producing hybridomas were generated. Furthermore we used this method to induce a specific antibody response against Legionella pneumophila. We thus established an effective protocol to generate monoclonal antibodies in vitro. By overcoming the necessity of in vivo immunization it may be the first step towards a universal strategy to generate antibodies from various species.

Brazil Moves Toward the Replacement of Animal Experimentation

2019 ◽  
Vol 47 (2) ◽  
pp. 71-81 ◽  
Author(s):  
Renato Ivan de Ávila ◽  
Marize Campos Valadares
Keyword(s):  
Animal Experimentation ◽  
Laboratory Animals ◽  
National Council ◽  
The European Union ◽  
Innovative Methods ◽  
Ethical And Legal Issues ◽  
Research And Education ◽  
Regulatory Acceptance

In Brazil, efforts towards the regulatory acceptance and implementation of innovative methods to replace experimental animal use in various fields began to gather force in 2008, with the approval of Law No. 11,794/2008 (the Arouca Law). This law represented a milestone, as it created the National Council for the Control of Animal Experimentation (CONCEA) to deal with the ethical and legal issues related to the use of laboratory animals. In 2014, CONCEA put together a framework for expanding the implementation of non-animal methodologies for use in research and education. It also promoted the regulatory acceptance in Brazil of 24 test guidelines, including 15 in vitro approaches. It should be emphasised that, in Brazilian legislation, replacement is generally based on the toxicological endpoint and not on the category of product, as tends to be the case in other countries (e.g. cosmetics in the European Union). The resolution-dependent deadlines for the obligatory replacement of in vivo methods with the CONCEA-approved tests are 2019 and 2021. Brazil has advanced considerably towards the replacement of animal experimentation, and in certain aspects, this has been in a highly progressive manner. However, there is still a lot of work to be done, especially considering the current political scenario with reduced investment in research, development and innovation. The chronology of significant events following the approval of the Arouca Law, which have contributed to the promotion of the Three Rs alternatives in Brazil, will be examined.

188 DEVELOPMENT OF AN EFFECTIVE WHOLE-OVARY PERFUSION SYSTEM

2015 ◽  
Vol 27 (1) ◽  
pp. 185
Author(s):  
S. Maffei ◽  
G. Galeati ◽  
G. Pennarossa ◽  
T. A. L. Brevini ◽  
G. Gandolfi
Keyword(s):  
Cell Proliferation ◽  
Ex Vivo ◽  
Animal Health ◽  
Basal Medium ◽  
Laboratory Animals ◽  
Large Animal ◽  
Perfusion System ◽  
Whole Ovaries

The different structures of a mammalian ovary require complex 3-dimensional interactions to function properly. It is difficult to access the ovary in vivo and to study its physiology in vitro, it is necessary to dissect its different parts and culture them individually. Although informative, this approach prevents the understanding of the role played by their interactions. Perfusion systems are available for ovaries of laboratory animals while organs of larger species have been maintained in culture only for a few hours. This has prompted us to develop a system that can preserve the function of a whole sheep ovary for a few days ex vivo so that it is available for analysis in controlled conditions. Twenty-four sheep ovaries were collected at the local abattoir; 18 were assigned randomly to 3 experimental groups (media A, B, and C) and 6 were immediately fixed in 10% formaldehyde and used as fresh controls. Whole ovaries were cultured for up to 4 days using a semi-open perfusion system. Organs were perfused through the ovarian artery, at a flow rate of 1.5 mL min–1 with basal medium (M199, 25 mM HEPES, 2 mM l-glutamine and 100 µg mL–1 antibiotic-antimycotic solution) supplemented with 0.4% fatty acid free BSA (medium A); or 0.4% BSA heat shock fraction (medium B); or 10% FBS, 50 ng mL–1 IGF-1, and 50 mg bovine insulin (medium C). Ovaries were stimulated with FSH (Folltropin®-V, Bioniche Animal Health Inc., Belleville, Ontario, Canada) changing medium in a pulsatile manner (1 mg mL–1 for 2 h; 0.5 mg mL–1 for 2 h; 0 mg mL–1 for 20 h), with the same cycle repeated each day of culture. At every change, aliquots were collected for oestradiol (E2) and progesterone (P4) quantification. After culture, ovaries were examined for follicular morphology, cell proliferation, and apoptotic rate. Statistical analysis was performed using one-way ANOVA (SPSS 20, IBM, Armonk, NY, USA). In media A and B, all morphological parameters showed a small but significant decrease compared to fresh control, only after 3 days of culture. The different BSA in medium B did not affect follicle morphology but significantly increased cell proliferation (medium A, 28.59 ± 3.26%; medium B, 32.04 ± 2.67%) and decreased apoptosis (medium A, 32.51 ± 5.92%; medium B, 24.55 ± 2.55%). In both media, steroid concentration increased after FSH pulses (E2 range 1.95–10.50 pg mL–1; P4 range 0.34–3.08 ng mL–1), reaching levels similar to those measurable in peripheral plasma. The presence of FBS, IGF-1, and insulin in medium C allowed extension of the culture period to 4 days with a percentage of intact follicles comparable to that observed after 3 days in media A and B. Moreover, proliferation rates were comparable to fresh controls. Steroid pattern changed with P4 values dropping close to zero (range 0.03–1.18 ng mL–1) and E2 level (range 23.59–94.98 pg mL–1) increasing 10-fold, achieving a concentration similar to that measured in the ovarian vein around oestrous. Our data indicate that it is possible to support viability of large animal whole ovaries for up to 4 days, providing a physiologically relevant model for studying ovarian functions in vitro. Research was supported by AIRC IG 10376 and by the Carraresi Foundation.

scholarly journals Regional distribution, developmental changes, and cellular localization of CNTF-mRNA and protein in the rat brain.

1991 ◽  
Vol 115 (2) ◽  
pp. 447-459 ◽  
Author(s):  
K A Stöckli ◽  
L E Lillien ◽  
M Näher-Noé ◽  
G Breitfeld ◽  
R A Hughes ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Olfactory Bulb ◽  
Cellular Localization ◽  
Time Course ◽  
Regional Distribution ◽  
Developmental Expression ◽  
Adult Rats

Ciliary neurotrophic factor (CNTF) is a potent survival molecule for a variety of embryonic neurons in culture. The developmental expression of CNTF occurs clearly after the time period of the physiological cell death of CNTF-responsive neurons. This, together with the sites of expression, excludes CNTF as a target-derived neuronal survival factor, at least in rodents. However, CNTF also participates in the induction of type 2 astrocyte differentiation in vitro. Here we demonstrate that the time course of the expression of CNTF-mRNA and protein in the rat optic nerve (as evaluated by quantitative Northern blot analysis and biological activity, respectively) is compatible with such a glial differentiation function of CNTF in vivo. We also show that the type 2 astrocyte-inducing activity previously demonstrated in optic nerve extract can be precipitated by an antiserum against CNTF. Immunohistochemical analysis of astrocytes in vitro and in vivo demonstrates that the expression of CNTF is confined to a subpopulation of type 1 astrocytes. The olfactory bulb of adult rats has comparably high levels of CNTF to the optic nerve, and here again, CNTF-immunoreactivity is localized in a subpopulation of astrocytes. However, the postnatal expression of CNTF in the olfactory bulb occurs later than in the optic nerve. In other brain regions both CNTF-mRNA and protein levels are much lower.

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