scholarly journals Acetylcholinesterases from Leaf-Cutting antAtta sexdens: Purification, Characterization, and Capillary Reactors for On-Flow Assays

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Adriana M. Dos Santos ◽  
Ariele C. Moreira ◽  
Bianca Rebelo Lopes ◽  
Mariana F. Fracola ◽  
Fernando G. de Almeida ◽  
...  
Keyword(s):  
Colorimetric Assay ◽  
Hydrolysis Product ◽  
Exchange Chromatography ◽  
Atta Sexdens ◽  
Enzyme Reactors ◽  
Phylogenetic Studies ◽  
Optimum Ph ◽  
Leaf Cutting ◽  
First Time ◽  
Hydrolysis Of

Acetylcholinesterase (AChE) is responsible for catalyzing the hydrolysis of the neurotransmitter acetylcholine (ACh) leading to acetate and choline (Ch) release. The inhibition of AChE produces a generalized synaptic collapse that can lead to insect death. Herein we report for the first time the isolation of two AChEs fromAtta sexdenswhich were purified by sulphate ammonium precipitation followed by ion exchange chromatography. AsAChE-A and AsAChE-B enzymes have optimum pH of 9.5 and 9.0 and higher activities in 30/50°C and 20°C, respectively, using acetylthiocholine (ATCh) as substrate. Immobilized capillary enzyme reactors (ICERs) were obtained for both enzymes (AsAChE-A-ICER and AsAChE-B-ICER) and their activities were measured by LC-MS/MS through hydrolysis product quantification of the natural substrate ACh. The comparison of activities by LC-MS/MS of both AChEs using ACh as substrate showed that AsAChE-B (free or immobilized) had the highest affinity. The inverse result was observed when the colorimetric assay (Elman method) was used for ATCh as substrate. Moreover, by mass spectrometry and phylogenetic studies, AsAChE-A and AsAChE-B were classified as belonging to AChE-2 and AChE-1 classes, respectively.

Social Carrying and Defensive Behavior During Colony Emigration in the Leaf-cutting Ant Atta sexdens

Sociobiology ◽  
2017 ◽  
Vol 64 (4) ◽  
pp. 492
Author(s):  
Lohan Valadares ◽  
Fábio S. Nascimento
Keyword(s):  
Body Surface ◽  
Defensive Behavior ◽  
The Body ◽  
Fungus Garden ◽  
Atta Sexdens ◽  
Defensive Strategies ◽  
Laboratory Conditions ◽  
Nesting Site ◽  
Leaf Cutting ◽  
First Time

In this work, we describe for the first time and under laboratory conditions, the behaviors related to social carrying and defensive strategies during colony emigration in the leaf-cutting ant Atta sexdens. Once colonies were laid on a tray under suboptimal conditions, groups of workers aggregated all over the body surface of the queen and brood, with mandibles half open and legs widely open in a ‘entangle’ formation. Queens were the first caste to be reallocated, followed respectively by the transportation of brood, newly-emerged workers, and pieces of fungus garden to the new nesting site. Contrary to what have been reported to the Myrmicinae species, adult transport followed a stereotyped sequence of acts involving approach, seize and transportation of newly-emerged workers to new target areas. Our results suggest that, in front of rapid unfavorable changes, leaf-cutting ants are capable of reorganize the nest in order to protect their members and resources.

Phorid Flies Parasitizing Leaf-Cutting Ants: Their Occurrence, Parasitism Rates, Biology and the First Account of Multiparasitism

Sociobiology ◽  
2016 ◽  
Vol 63 (4) ◽  
pp. 1015 ◽  
Author(s):  
Marcos Antonio Lima Bragança ◽  
Filipe Viegas Arruda ◽  
Lana Rubia Rocha Souza ◽  
Hendria Cirqueira Martins ◽  
Terezinha Maria Castro Della Lucia
Keyword(s):  
Life Span ◽  
Atta Sexdens ◽  
Atta Laevigata ◽  
Central Brazil ◽  
Parasitism Rates ◽  
Leaf Cutting ◽  
Phorid Flies ◽  
First Time

The leaf-cutting ants Atta sexdens (Linnaeus) and Atta laevigata (Smith) were parasitized by the following phorid flies: Apocephalus attophilus Borgmeier, Apocephalus vicosae Disney, Myrmosicarius grandicornis Borgmeier and species of Eibesfeldtphora Disney. It is also related here that the area of occurrence of phorids parasitizing A. sexdens was extended to include Central Brazil. The rate of parasitism on A. sexdens was three times lower than the rate found on A. laevigata; most common flies were, respectively, M. grandicornis in A. sexdens and A. attophilus in A. laevigata. This last phorid showed the shortest life span but the higher percentage of emergence. Multiparasitism on workers of A. sexdens and of A. laevigata involving three combinations of four phorid species was rare and is here related for the first time for leaf-cutting ants.

Post-proline endopeptidase. Partial purification and characterization of the enzyme from pig kidneys

1982 ◽  
Vol 47 (4) ◽  
pp. 1139-1148 ◽  
Author(s):  
Karel Hauzer ◽  
Linda Servítová ◽  
Tomislav Barth ◽  
Karel Jošt
Keyword(s):  
Specific Activity ◽  
Gel Filtration ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Optimum Ph ◽  
Hydrolysis Of ◽  
Prolyl Leucyl Glycinamide

Post-proline endopeptidase was isolated from pig kidneys and partially purified. The procedure consisted of fractionation with ammonium sulphate, ion exchange chromatography on DEAE-Sephadex A-50, gel filtration on Sephadex G-200 and rechromatography on DEAE-Sephadex A-50. The preparation had 55 times higher specific activity than the crude extract and did not contain any contaminating enzymic activities. The enzyme cleaved a number of proline-containing peptides and was strictly specific in catalyzing the hydrolysis of the peptide bond on the carboxyl side of the proline residue. The optimum pH for the hydrolysis of the synthetic peptides benzyl-oxycarbonylglycyl-prolyl-leucyl-glycinamide and benzyloxycarbonyl-glycyl-proline β-naphtylamide was 7.8-8.0 and, in the case of benzyloxycarbonylglycyl-proline p-nitroanilide, 7.2 to 7.5. For the hydrolysis of the tetrapeptide benzyloxycarbonylglycyl-prolyl-leucyl-glycinamide, the Km value of 75 μ mol l-1 was obtained.

scholarly journals Survey of leaf-cutting ant species in native vegetation and monocultures in the State of Goiás, Brazil

2020 ◽  
Vol 15 (1) ◽  
pp. 237-241
Author(s):  
Filipe Viegas de Arruda ◽  
Marcos Antônio Pesquero ◽  
Marcos Filipe Pesquero ◽  
João Danilo dos Santos
Keyword(s):  
The State ◽  
Native Vegetation ◽  
Atta Sexdens ◽  
Atta Laevigata ◽  
Leaf Cutting ◽  
First Time

Leaf-cutting ants are distributed exclusively in the Americas. For this study, we sampled different areas of native vegetation and monocultures to survey the leaf-cutting ants that occur in the State of Goiás, and to what environments they are associated. We recorded six species of leaf-cutting ants: Atta sexdens, Atta laevigata, Acromyrmex subterraneus, Acromyrmex disciger, Acromyrmex ambiguus, and Acromyrmex hispidus. The last four were registered for the first time for the State of Goiás.

Purification and characterization of an extracellular chitinase from the entomopathogen Metarhizium anisopliae

1997 ◽  
Vol 43 (4) ◽  
pp. 322-327 ◽  
Author(s):  
Alexandre de Siqueira Pinto ◽  
Cristine Chaves Barreto ◽  
Marilene Henning Vainstein ◽  
Augusto Schrank ◽  
Cirano José Ulhoa
Keyword(s):  
Metarhizium Anisopliae ◽  
Enzyme Purification ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Anion Exchange Chromatography ◽  
Enzyme Characterization ◽  
Exchange Chromatography ◽  
Optimum Ph ◽  
Hydrolysis Of

Chitinases are produced by Metarhizium anisopliae when it is grown in the presence of chitin. A chitinase from the culture filtrate of Metarhizium anisopliae was successively purified by precipitation with ammonium sulphate, followed by anion-exchange chromatography on DEAE-Sephacel. The purified enzyme, which has a molecular mass of approximately 30 kDa by sodium dodecyl sulphate – polyacrylamide gel electrophoresis, catalyses the hydrolysis of p-nitrophenyl β-N-diacetylchitobiose with an apparent Km of 0.537 mmol and Vmax of 4.86 nmol∙mL−1∙min−1. The optimum pH and temperature were 4.5–5.0 and 40–45 °C, respectively.Key words: chitinases, Metarhizium anisopliae, enzyme purification, enzyme characterization.

scholarly journals Assay of Poly(3-Hydroxybutyrate) Depolymerase Activity and Product Determination

2006 ◽  
Vol 72 (9) ◽  
pp. 6094-6100 ◽  
Author(s):  
Birgit Gebauer ◽  
Dieter Jendrossek
Keyword(s):  
High Performance ◽  
Ralstonia Eutropha ◽  
Hydrolysis Product ◽  
Hydrolysis Rates ◽  
Product Identification ◽  
Consumption Rates ◽  
Ph Stat ◽  
First Time ◽  
Hydrolysis Of

ABSTRACT Two methods for accurate poly(3-hydroxybutyrate) (PHB) depolymerase activity determination and quantitative and qualitative hydrolysis product determination are described. The first method is based on online determination of NaOH consumption rates necessary to neutralize 3-hydroxybutyric acid (3HB) and/or 3HB oligomers produced during the hydrolysis reaction and requires a pH-stat apparatus equipped with a software-controlled microliter pump for rapid and accurate titration. The method is universally suitable for hydrolysis of any type of polyhydroxyalkanoate or other molecules with hydrolyzable ester bonds, allows the determination of hydrolysis rates of as low as 1 nmol/min, and has a dynamic capacity of at least 6 orders of magnitude. By applying this method, specific hydrolysis rates of native PHB granules isolated from Ralstonia eutropha H16 were determined for the first time. The second method was developed for hydrolysis product identification and is based on the derivatization of 3HB oligomers into bromophenacyl derivates and separation by high-performance liquid chromatography. The method allows the separation and quantification of 3HB and 3HB oligomers up to the octamer. The two methods were applied to investigate the hydrolysis of different types of PHB by selected PHB depolymerases.

Antibiotic-producing bacteria associated with the nests of the leaf-cutting ant Atta sexdens rubropilosa

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
EA Silva-Junior ◽  
CR Paludo ◽  
FS Nascimento ◽  
CR Currie ◽  
J Clardy ◽  
...  
Keyword(s):  
Atta Sexdens ◽  
Atta Sexdens Rubropilosa ◽  
Leaf Cutting

scholarly journals The synergistic interference effect of silica nanoparticles concentration and the wavelength of ELISA on the colorimetric assay of cell toxicity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fariba Abbasi ◽  
Hassan Hashemi ◽  
Mohammad Reza Samaei ◽  
Amir SavarDashtaki ◽  
Abooalfazl Azhdarpoor ◽  
...  
Keyword(s):  
Mtt Assay ◽  
Interference Effect ◽  
Polynomial Regression ◽  
Colorimetric Assay ◽  
Synergistic Effects ◽  
Cell Toxicity ◽  
Diphenyltetrazolium Bromide ◽  
Nanoparticles Concentration ◽  
Artificial Neural Network Ann ◽  
First Time

AbstractThe 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay is the most common method for the determination of cell toxicity, but some factors limit the sensitivity of this method, such as pH. Less attention had been paid to the interference effect of optical and plasmonic properties of SiO2 nanoparticles (NPs) in the wavelength range assigned to MTT. This study investigated the synergistic interference effect of SiO2 NPs and wavelength on MTT assay for the first time. The examined variables included the type of SiO2 NPs concentrations (1, 10, and 100 mM) and different wavelengths (470, 490, 520, and 570 nm). The results showed that optical density (OD) increased (p < 0.05) when wavelength and the concentration of crystalline SiO2 NPs increased. So, the maximum OD at 10 and 100 mM were attributed to crystalline SiO2 NPs (p < 0.05) due to the functional group, whereas it was related to amorphous at 1 mM (p > 0.05). According to polynomial regression modeling (PRM), the maximum interference effect was predicted at crystalline SiO2 NPs and wavelength > 550 nm. Besides, the synergistic effects of SiO2 NPs, wavelength, and concentration of NPs had been a good fitting with first-order PRM. Thus, the concentration of SiO2 NPs had a confounder factor in colorimetric for MTT assay. The best artificial neural network (ANN) structure was related to the 3:7:1 network (Rall = 0.936, MSE = 0.0006, MAPE = 0.063). The correlation between the actual and predicted data was 0.88. As SiO2 NPs presence is an interfering factor in MTT assay concerning wavelength, it is suggested wavelength use with minimum confounding effect for MTT assay.

scholarly journals Optimisation of Recombinant Myrosinase Production in Pichia pastoris

2021 ◽  
Vol 22 (7) ◽  
pp. 3677
Author(s):  
Zuzana Rosenbergová ◽  
Kristína Kántorová ◽  
Martin Šimkovič ◽  
Albert Breier ◽  
Martin Rebroš
Keyword(s):  
Pichia Pastoris ◽  
Plant Defence ◽  
Plant Secondary Metabolites ◽  
Specific Productivity ◽  
Fermentation Conditions ◽  
Threefold Increase ◽  
Dry Cell Weight ◽  
First Time ◽  
Hydrolysis Of ◽  
Dry Cell

Myrosinase is a plant defence enzyme catalysing the hydrolysis of glucosinolates, a group of plant secondary metabolites, to a range of volatile compounds. One of the products, isothiocyanates, proved to have neuroprotective and chemo-preventive properties, making myrosinase a pharmaceutically interesting enzyme. In this work, extracellular expression of TGG1 myrosinase from Arabidopsis thaliana in the Pichia pastoris KM71H (MutS) strain was upscaled to a 3 L laboratory fermenter for the first time. Fermentation conditions (temperature and pH) were optimised, which resulted in a threefold increase in myrosinase productivity compared to unoptimised fermentation conditions. Dry cell weight increased 1.5-fold, reaching 100.5 g/L without additional glycerol feeding. Overall, a specific productivity of 4.1 U/Lmedium/h was achieved, which was 102.5-fold higher compared to flask cultivations.

Darstellung, Schwingungsspektren und Normalkoordinatenanalyse von Chloro-Bromo-Rhodaten(III) / Preparation, Vibration Spectra and Normal Coordinate Analysis of Chloro-Bromo-Rhodates(III)

1989 ◽  
Vol 44 (10) ◽  
pp. 1221-1227 ◽  
Author(s):  
W. Preetz ◽  
W. Kuhr
Keyword(s):  
Exchange Chromatography ◽  
Trans Isomers ◽  
Normal Coordinate ◽  
Valence Force ◽  
Trans Influence ◽  
Diethylaminoethyl Cellulose ◽  
Point Groups ◽  
First Time ◽  
Ir And Raman ◽  
Good Agreement

The mixed chloro-bromo-rhodates(III) [RhClnBr6-n]3-, n = 1-5, have been separated for the first time by ion exchange chromatography on diethylaminoethyl-cellulose. Due to the stronger trans-effect of Br, as compared with Cl, on treatment of [RhBr6]3- with conc. HCl nearly pure cis/fac-isomers for n = 2, 3, 4 are formed. The reaction of [RhCl6]3- with conc. HBr yields mixtures of the cis/trans-isomers for n = 2, 4, which cannot be separated, but mer-[RhCl3Br3]3 is formed stereospecifically. The IR and Raman spectra of all isolated mixed ligand complexes are completely assigned according to point groups Oh, D3d, C4v, C3v and C2v, supported by normal coordinate analyses based on a general valence force field. The good agreement of calculated and observed frequencies confirms the assignments. Due to the stronger trans-influence of Br as compared to Cl, in all asymmetric Cl—Rh—Br axes the Rh—Br bonds are strengthened and the Rh—Cl bonds are weakened, indicated by valence force constants for Rh—Br approximately 14% higher, for Rh—Cl 10% lower, as compared with the values calculated for symmetric Br—Rh—Br and Cl—Rh—Cl axes, respectively.

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