A educação ambiental (EA) favorece o engajamento dos estudantes para que possam agir como agentes de transformação perante as problemáticas socioambientais. A presente pesquisa foi realizada em uma ...escola pública de Ensino Fundamental (EF) do município de Belo Jardim, estado de Pernambuco. Tem caráter qualitativo e exploratório, enquadrando-se como documental e participante. Metodologicamente, foram utilizados os instrumentos: Projeto Político Pedagógico (PPP), entrevista semiestruturada e uma oficina pedagógica objetivando investigar a inserção da EA na comunidade escolar. Os dados foram analisados considerando abordagem da EA-Crítica com a finalidade de investigar a EA na prática de docentes do 2º ao 5º ano do EF. Os resultados mostraram que o PPP aborda a temática apenas em datas comemorativas. Nas entrevistas, os participantes apresentaram concepção conservacionista e resolutiva e, ausência da temática na formação inicial, além de práticas pontuais quando abordam atividades de EA com os estudantes. A oficina despertou um novo olhar para a EA. Assim, destaca-se a importância da escola enquanto formadora de estudantes conhecedores dos seus direitos e deveres perante o meio ambiente. Este estudo, portanto, contribui para novas configurações na inserção da EA na escola investigada, além de colaborar no campo da pesquisa e do conhecimento da área.
Free extracellular heme has been shown to activate several compartments of innate immunity, acting as a danger-associated molecular pattern (DAMP) in hemolytic diseases. Although localized ...endothelial barrier (EB) disruption is an important part of inflammation that allows circulating leukocytes to reach inflamed tissues, non-localized/deregulated disruption of the EB can lead to widespread microvascular hyperpermeability and secondary tissue damage. In mouse models of sickle cell disease (SCD), EB disruption has been associated with the development of a form of acute lung injury that closely resembles acute chest syndrome (ACS), and that can be elicited by acute heme infusion. Here we explored the effect of heme on EB integrity using human endothelial cell monolayers, in experimental conditions that include elements that more closely resemble
conditions. EB integrity was assessed by electric cell-substrate impedance sensing in the presence of varying concentrations of heme and sera from SCD patients or healthy volunteers. Heme caused a dose-dependent decrease of the electrical resistance of cell monolayers, consistent with EB disruption, which was confirmed by staining of junction protein VE-cadherin. In addition, sera from SCD patients, but not from healthy volunteers, were also capable to induce EB disruption. Interestingly, these effects were not associated with total heme levels in serum. However, when heme was added to sera from SCD patients, but not from healthy volunteers, EB disruption could be elicited, and this effect was associated with hemopexin serum levels. Together our
studies provide additional support to the concept of heme as a DAMP in hemolytic conditions.
In recent years, lectins have been identified as alternative agents against
Aedes aegypti
during the aquatic phases of its life cycle. For example, chitin-binding lectin from
Myracrodruon urundeuva
...leaf (MuLL) can function as a larvicide. In this study, we investigated whether MuLL can also act as an ovicide against this insect.
Aedes aegypti
eggs were incubated with MuLL for 72 h to determine the concentration at which the hatching rate reduces by 50% (EC
50
). The effects of MuLL on the egg surface structure were evaluated using scanning electron microscopy (SEM), and the possible interaction of MuLL with the internal structures of eggs and embryos was investigated using MuLL-fluorescein isothiocyanate (FITC) conjugate. MuLL acted as an ovicidal agent with an EC
50
of 0.88 mg/mL. The SEM analysis revealed that eggs treated with MuLL for 24 and 48 h no longer had tubercles and did not show a well-defined exochorionic network. In addition, deformation and degeneration of the surface were observed after 72 h. Fluorescence microscopy showed that MuLL penetrated the eggs 48 h after incubation and was detected in the upper portion of the embryo’s gut. After 72 h, MuLL was observed in the serosal cuticle and digestive tract. In conclusion, MuLL can function as an ovicidal agent against
A. aegypti
through damage to the surface and internal structures of the eggs.
Aedes aegypti
transmits the viruses that cause yellow and dengue fevers. Vector control is essential, since a vaccine for dengue has not as yet been made available. This work reports on the ...larvicidal activity of
Myracrodruon urundeuva
leaf lectin (MuLL) against
A. aegypti
fourth-stage larvae (L
4
). Also, the resistance of MuLL to digestion by L
4
gut proteases and the effects of MuLL on protease, trypsin-like and α-amylase activities from L
4
gut were evaluated to determine if lectin remains active in
A. aegypti
gut and if insect enzyme activities can be modulated by MuLL. MuLL promoted mortality of L
4
with LC
50
of 0.202 mg/ml. Haemagglutinating activity of MuLL was detected even after incubation for 96 h with L
4
gut preparation containing protease activity. MuLL affected the activity of gut enzymes, inhibiting protease and trypsin activities and stimulating α-amylase activity. The results suggest that MuLL may become a new biodegradable larvicidal agent for dengue control. Larvicidal activity of MuLL may be linked to its resistance to proteolysis by larval enzymes and interference in the activity of digestive larval enzymes.
This study describes the purification of Bixa orellana L. leaf lectin (BoLL) and the evaluation of its antimicrobial activity and in vivo toxicity. BoLL was isolated from saline extract of leaves ...through protein precipitation with ammonium sulfate (60% saturation) followed by ion exchange (CM-Sephadex) and size exclusion (Sephadex G-75) chromatographies. The lectin was characterized by polyacrylamide gel electrophoresis under denaturing conditions (SDS-PAGE), stability towards heating and pH variation, as well as influence of ions on its hemagglutinating activity (HA). HA inhibition assay by different carbohydrates and glycoproteins was also performed. The antimicrobial activity of BoLL was investigated against pathogens for humans and plants. In vivo acute toxicity in mice was assessed using a dose of 100 mg/kg per os or i.p. BoLL was isolated with high specific HA (purification fold: 53.89) and showed a single 19-kDa polypeptide band in SDS-PAGE. BoLL SHA increased in the presence of 20 mM Mg2+ ions, was resistant to heating at 100 °C, and stable at acidic pH range. HA inhibition was detected especially by glycoproteins, but also by monosaccharides. BoLL showed bacteriostatic and bactericidal effects against Escherichia coli minimum inhibitory (MIC) and bactericidal (MBC) concentrations of 400 and 800 μg/mL, respectively and Staphylococcus aureus (MIC and MBC: 400 μg/mL), as well as bacteriostatic effect against Bacillus megaterium and Micrococcus luteus (MIC: 18.2 and 800 μg/mL, respectively). No changes were observed in hematological, biochemical, and behavioral parameters in the acute toxicity test. However, animals treated with BoLL at 100 mg/kg per os or i.p. showed histopathological alterations in the liver, spleen, and kidneys. In conclusion, our data add new biotechnological value for B. orellana leaves, since they contain a thermostable lectin with antibacterial activity, which stimulate future studies aiming at its biomedical application. However, caution should be considered in future studies due to some signs of toxicity in mice.
•A protocol for purification of a lectin from Bixa orellana leaf (BoLL) was defined.•BoLL showed a single 19-kDa polypeptide band in SDS-PAGE.•Hemagglutinating activity of BoLL increased in the presence of Mg2+ ions, was resistant to heating at 100 °C, and stable at acidic pH range.•BoLL showed bacteriostatic and bactericidal effects•BoLL (100 mg/kg per os or i.p.) did not cause the death of Swiss mice.
Lectins are carbohydrate-binding proteins with several bioactivities, including antimicrobial properties.
Portulaca elatior
is a species found at Brazilian Caatinga and data on the biochemical ...composition of this plant are scarce. The present work describes the purification of
P. elatior
leaf lectin (PeLL) as well as the assessment of its antimicrobial activity and toxicity. PeLL, isolated by chromatography on a chitin column, had native liquid charge and subunit composition evaluated by electrophoresis. Hemagglutinating activity (HA) of PeLL was determined in the presence of carbohydrates or divalent cations, as well as after heating and incubation at different pH values. Changes in the lectin conformation were monitored by evaluating intrinsic tryptophan fluorescence and using the extrinsic probe bis-ANS. Antimicrobial activity was evaluated against
Pectobacterium
strains and
Candida
species
.
The minimal inhibitory (MIC), bactericidal (MBC), and fungicidal (MFC) concentrations were determined. Finally, PeLL was evaluated for in vitro hemolytic activity in human erythrocytes and in vivo acute toxicity in mice (5 and 10 mg/kg b.w
.
per os). PeLL (pI 5.4; 20 kDa) had its HA was inhibited by mannose, galactose, Ca
2+
, Mg
2+
, and Mn
2+
. PeLL HA was resistant to heating at 100 °C, although conformational changes were detected. PeLL was more active in the acidic pH range, in which no conformational changes were observed. The lectin presented MIC and MBC of 0.185 and 0.74 μg/mL for all
Pectobacterium
strains, respectively; MIC of 1.48 μg/mL for
C. albicans
,
C
.
tropicalis
, and
C. krusei
; MIC and MFC of 0.74 and 2.96 μg/mL for
C. parapsilosis
. No hemolytic activity or signs of acute toxicity were observed in the mice. In conclusion, a new, low-toxic, and thermostable lectin was isolated from
P. elatior
leaves, being the first plant compound to show antibacterial activity against
Pectobacterium
.
The digestive apparatus of termites may have several biotechnological applications, as well as being a target for pest control. This report discusses the detection of cellulases (endoglucanase, ...exoglucanase, and β-glucosidase), hemicellulases (β-xylosidase, α-l-arabinofuranosidase, and β-d-xylanase), α-amylase, and proteases (trypsin-like, chymotrypsin-like, and keratinase-type) in gut extracts from Nasutitermes corniger workers and soldiers. Additionally, the effects of pH (3.0–11.0) and temperature (30–100°C) on enzyme activities were evaluated. All enzymes investigated were detected in the gut extracts of worker and soldier termites. Endoglucanase and β-xylanase were the main cellulase and hemicellulase, respectively. Zymography for proteases of worker extracts revealed polypeptides of 22, 30, and 43kDa that hydrolyzed casein, and assays using protease inhibitors showed that serine proteases were the main proteases in worker and soldier guts. The determined enzyme activities and their response to different pH and temperature values revealed that workers and soldiers contained a distinct digestive apparatus. The ability of these termites to efficiently digest the main components of lignocellulosic materials stimulates the purification of gut enzymes. Further investigation into their biotechnological potential as well as whether the enzymes detected are produced by the termites or by their symbionts is needed.
Deterioration and degradation of grains by storage insect pests lead to economic losses of several billion dollars and affect food security. Sitophilus zeamais is responsible for pre- and ...post-harvest damages to maize. The high toxicity of synthetic insecticides and the development of resistance by insects to the chemicals currently used stimulate the investigation of plant-derived insecticides as new alternatives for pest control. In this study, we report the effects of diets containing Myracrodruon urundeuva leaf extract (10–150 mg/g) and lectin (MuLL; 3–150 mg/g) on the survival, feeding, and nutrition of the storage pest S. zeamais. The digestive enzyme activity in gut extracts from the insects reared on the leaf extract (25 mg/g) or MuLL (15 mg/g) diets was also evaluated. The leaf extract induced mortality (LC50: 72.4 mg/g), while MuLL (30–150 mg/g) exerted strong feeding deterrence. The leaf extract and MuLL promoted the loss of biomass, as reflected in the negative values for relative biomass gain rates and efficiencies in converting ingested food. Protease, trypsin-like, acid phosphatase, and amylase activities in the insects reared on leaf extract or MuLL diets were significantly (P < 0.05) lower than those in the control insects. MuLL ingestion also significantly reduced (P < 0.05) endoglucanase and alkaline phosphatase activities. In conclusion, the leaf extract and MuLL have the potential for S. zeamais control by killing adults and preventing the use of a food source, respectively. The deleterious effects of the extract and lectin on S. zeamais may be linked to enzyme inhibition and consequent suppression of digestive processes.
•Sitophilus zeamais were reared on diets with Myracrodruon urundeuva leaf extract and lectin (MuLL).•The leaf extract killed S. zeamais adults through ingestion.•MuLL showed deterrent effect leading the insects to starve until death.•Extract and MuLL caused loss of biomass due to inefficiency in food conversion.•The effects of the extract and lectin may be linked to enzyme inhibition.
During the last decades, there has been an increasing interest in natural compounds for the control of insect pest. The present study evaluated the insecticidal activity of a saline extract of ...Abarema cochliocarpos bark against Aedes aegypti, Sitophilus zeamais, Nasutitermes corniger, and Fusarium spp. Thin layer chromatography revealed the presence of anthraquinones, saponins, and hydrolyzable and condensed tannins in the extract. High-performance liquid chromatography with a diode-array detector confirmed the presence of gallic acid, catechin, ellagic acid, and catechin derivatives. The presence of lectins and trypsin inhibitor was also confirmed. The extract exhibited insecticidal activity against the fourth-stage larvae of A. aegypti (LC50- 8.22 μg/mL). Furthermore, the extract did not exhibit insecticidal activity against the adults of S. zeamais even 7 d after treatment. However, a strong deterrent effect was observed. The extract promoted the mortality of N. corniger workers and soldiers (LC50: 1.89 and 1.83 mg/mL, respectively). The extract (0.2–0.8 mg/mL) inhibited the mycelial growth of F. oxysporum (69.0%–83.1% inhibition) and F. lateritium (23.0%–59.0% inhibition). These results indicate that the bark of A. cochliocarpos is a source of bioactive agents that are effective against insect and fungal pests.
•The extract contained anthraquinones, saponins, hydrolyzable and condensed tannins, lectins and trypsin inhibitor.•It was confirmed the presence of gallic acid, catechin, ellagic acid, and catechin derivatives.•The extract exhibited insecticidal activity against Aedes aegypti larvae Nasutitermes corniger workers and soldiers.•The extract exerted strong deterrent effect on adults of Sitophilus zeamais.•The extract inhibited the mycelial growth of Fusarium oxysporum and Fusarium lateritium.
Aedes aegypti transmits etiologic agents of yellow fever and dengue. Vaccine for dengue virus is not available and vector control is essential to minimize dengue incidence. This report deals with the ...larvicidal activity of lectins isolated from
Myracrodruon urundeuva bark (MuBL) and heartwood (MuHL). The lectins were isolated by ammonium sulphate treatment of crude extracts followed by chromatography on chitin. MuBL and MuHL were evaluated by electrophoresis under native (PAGE) and denaturing conditions (SDS-PAGE). Carbohydrate specificity of lectins was evaluated by hemagglutinating activity (HA) inhibition assay using
N-acetyl-
d-glucosamine and by affinity chromatography on
N-acetyl-
d-glucosamine immobilized in agarose gel. Larvicidal activity against
A. aegypti was investigated with the extracts, salt fractions and isolated lectins. MuBL and MuHL were characterized by PAGE as basic proteins of molecular masses of 14.0 and 14.4 kDa, respectively. The interaction of lectins with
N-acetylglucosamine was detected by inhibition of HA by monosaccharide and lectin adsorptions on
N-acetyl-
d-glucosamine matrix. All
M. urundeuva preparations promoted larvae mortality. LC
16, LC
50 and LC
84 values of 0.077, 0.125, 0.173 for MuBL and 0.03, 0.04 and 0.05 mg/mL for MuHL were obtained. To our knowledge this is the first report of larvicidal activity of lectins against
A. aegypti.
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