.
In this paper, we describe in detail the BMV (
Biréfringence Magnétique du Vide
) experiment, a novel apparatus to study the propagation of light in a transverse magnetic field. It is based on a ...very high finesse Fabry-Perot cavity and on pulsed magnets specially designed for this purpose. We justify our technical choices and we present the current status and perspectives.
New naphthoquinone derivatives were synthesized and assayed against bloodstream trypomastigote forms of
Trypanosoma cruzi, the etiological agent of Chagas’ disease. From nor-lapachol were prepared ...five substituted
ortho-naphthofuranquinones, a non-substituted
para-naphthofuranquinone, a new oxyrane and an azide and from α-lapachone a new non-substituted
para-naphthofuranquinone. Other five substituted
ortho-naphthofuranquinones, recently designed as toxic to cancer lines, were also evaluated.
New naphthoquinone derivatives were synthesized and assayed against bloodstream trypomastigote forms of
Trypanosoma cruzi, the etiological agent of Chagas’ disease. The compounds were rationalized based on hybrid drugs and appear as important compounds against this parasite. From nor-lapachol were prepared five substituted
ortho-naphthofuranquinones, a non-substituted
para-naphthofuranquinone, a new oxyrane and an azide and from α-lapachone a new non-substituted
para-naphthofuranquinone. Other five substituted
ortho-naphthofuranquinones recently designed as cytotoxic, were also evaluated. The most active compounds were the ortho naphthofuranquinones 3-(4-methoxyphenylamino)-2,3-dihydro-2,2-dimethylnaphtho1,2-
bfuran-4,5-dione and 3-(3-nitrophenylamino)-2,3-dihydro-2,2-dimethylnaphtho1,2-
bfuran-4,5-dione with trypanocidal activity higher than that of benznidazole, the standard drug. The compounds were rationalized based on hybrid drugs and appear as important compounds against
T. cruzi. The trypanocidal activity of these substances endowed with redox properties representing a good starting point for a medicinal chemistry program aiming the chemotherapy of Chagas’ disease.
Bacterial resistance to the available marketed drugs has prompted the search of novel therapies; especially in regards of anti-virulence strategies that aim to make bacteria less pathogenic and/or ...decrease their probability to become resistant to therapy. Cinnamaldehyde is widely known for its antibacterial properties through mechanisms that include the interaction of this compound with bacterial cell walls. However, only a handful of studies have addressed its effects on bacterial virulence, especially when tested at sub-inhibitory concentrations. Herein, we show for the first time that cinnamaldehyde is bactericidal against
and
multidrug resistant strains and does not promote bacterial tolerance. Cinnamaldehyde actions were stronger on
as it was able to inhibit its hemolytic activity on human erythrocytes and reduce its adherence to latex. Furthermore, cinnamaldehyde enhanced the serum-dependent lysis of
.
testing of cinnamaldehyde in
larvae infected with
, showed this compound improves larvae survival whilst diminishing bacterial load in their hemolymph. We suggest that cinnamaldehyde may represent an alternative therapy to control
-induced bacterial infections as it presents the ability to reduce bacterial virulence/survival without promoting an adaptive phenotype.
There is great interest in the use of graphene and derivatives in the production of polymer nanocomposites as it provides improvements in the properties of the materials to which they are associated. ...Such improvements depend heavily on filler dispersion and the interaction between the nanomaterials and the matrix. This work aimed to study the compatibility of graphene oxide (GO) with a poly(ethylene terephthalate) matrix. For this, graphite was modified using Hummers method, using reaction times of 3 and 6 h. The obtained GO was functionalized with amine, amide, and magnetite groups (FGO). The effects of the oxidation degree, functionalization and concentration of the nanofillers on the dispersion and consequently on the properties of the polymer nanocomposites were evaluated. The nanocomposites were synthesized by the solid–solid deposition method followed by the melt mixing technique. It was observed that lower concentrations of nanofiller associated with the lower degree of oxidation and functionalization improved the interaction of the nanofillers with the matrix, which resulted in better mechanical properties under tensile stresses for strain at break, maximum stress, Young's modulus and toughness. It was also observed that the glass transition and crystallization of nanocomposites increased due to a nucleating effect of the nanofillers.
Why are measles and rubella returning in Brazil? Borges, Lysandro P; Barreto, Marina Dos S; Santos, Ronaldy S ...
Anais da Academia Brasileira de Ciências,
01/2023, Letnik:
95, Številka:
suppl 2
Journal Article
1,2,3-Triazole derivatives of nor-β-lapachone were synthesized and assayed against the infective bloodstream trypomastigote form of
Trypanosoma cruzi, the etiological agent of Chagas disease. All the ...derivatives were more active than the original quinones, with IC
50/1 day values in the range of 17 to 359
μM, the apolar phenyl substituted triazole
6 being the most active compound. These triazole derivatives of nor-β-lapachone emerge as interesting new lead compounds in drug development for Chagas disease.
Several 1,2,3-triazole derivatives of nor-β-lapachone were synthesized and found to display potent activity
in vitro against
Trypanosoma cruzi. These naphthoquinoidal triazoles emerge as interesting new lead compounds in drug development for Chagas disease.
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Several arylamino derivatives of nor-β-lapachone and one derivative of nor-α-lapachone were synthesized in moderate to high yields and found to show very potent cytotoxicity against six neoplastic ...cancer cells: SF-295 (central nervous system), HCT-8 (colon), MDAMB-435 (breast), HL-60 (leukemia), PC-3 (prostate) and B-16 (murine melanoma), with IC
50 below 1
μg/mL.
Several arylamino derivatives of nor-β-lapachone were synthesized in moderate to high yields and found to show very potent cytotoxicity against six neoplastic cancer cells: SF-295 (central nervous system), HCT-8 (colon), MDAMB-435 (breast), HL-60 (leukaemia), PC-3 (prostate), and B-16 (murine melanoma), with IC
50 below 1
μg/mL. Their cytotoxicities were compared to doxorubicin and with their synthetic precursors, β-lapachone and nor-β-lapachone. The activity against a normal murine fibroblast L-929 showed that some of the compounds were selective against cancer cells. The absence of hemolytic activity (EC
50
>
200
μg/mL), performed with erythrocyte suspensions, suggests that the cytotoxicity of the compounds was not related to membrane damage of mouse erythrocytes. For comparison purposes, one isomeric compound based on nor-α-lapachone was also synthesized and showed lower activity than the related
ortho-derivative. The modified arylamino quinones appear as interesting new lead compounds in anti-cancer drug development.
ABSTRACT This study aimed to calibrate and test the SARRA-H (Système d’Analyse Régionale des Risques Agroclimatologiques) crop model for cowpea, as well as conducting a climate risk zoning for this ...crop in a region located in Eastern Amazon, allowing the identification of locations and sowing dates that favor the production considering both the water deficit and the probability of occurrence of severe rains during the harvest period. The model was calibrated and validated with data from experiments conducted between 2013 and 2016 in the municipality of Castanhal, PA, Brazil. Low climate risk areas were defined as those that had a water requirement satisfaction index (WRSI) greater than or equal to 0.5 in the reproductive phase combined with the occurrence of rainfall below 20 mm at the harvest for, at least, 80% of the years for which planting was simulated. The model was able to simulate the water balance, growth and development of cowpea under the climate and soil conditions of the studied location with high precision and accuracy. The optimal period for sowing cowpea comprises the interval between June 5th and 25th for regions located above 2° S and between March 25th and April 15th for regions below 2º S.
RESUMO Esta pesquisa teve como objetivo calibrar e testar o modelo de cultura SARRA-H (Système d’Analyse Régionale des Risques Agroclimatologiques) para o caupi, bem como realizar o zoneamento de risco climático para esta cultura em uma região localizada na Amazônia Oriental, a fim de permitir a identificação de locais e datas de semeadura que favoreçam a produção considerando tanto o déficit hídrico como a probabilidade de ocorrência de chuvas severas durante o período da colheita. O modelo foi calibrado e validado com dados de experimentos realizados entre 2013 e 2016 no município de Castanhal, PA. As áreas de baixo risco climático foram definidas como aquelas que apresentaram índice de satisfação da necessidade hídrica (WRSI) maior ou igual a 0,5 na fase reprodutiva combinado com a ocorrência de chuvas abaixo de 20 mm na colheita por, pelo menos, 80% dos anos onde foi simulado o plantio. O modelo foi capaz de simular o balanço hídrico, crescimento e desenvolvimento do feijão-caupi nas condições climáticas e de solo da região estudada com boa precisão e exatidão. O período de ótima semeadura para o feijão-caupi compreende o intervalo entre 5 e 25 de junho para regiões localizadas acima de 2° S, e entre 25 de março e 15 de abril para regiões abaixo de 2º S.
Sugarcane (Saccharum spp.) is a clonally propagated outcrossing polyploid crop of great importance in tropical agriculture. Up to now, all sugarcane genetic maps had been developed using either ...full-sib progenies derived from interspecific crosses or from selfing, both approaches not directly adopted in conventional breeding. We have developed a single integrated genetic map using a population derived from a cross between two pre-commercial cultivars ('SP80-180' x 'SP80-4966') using a novel approach based on the simultaneous maximum-likelihood estimation of linkage and linkage phases method specially designed for outcrossing species. From a total of 1,118 single-dose markers (RFLP, SSR and AFLP) identified, 39% derived from a testcross configuration between the parents segregating in a 1:1 fashion, while 61% segregated 3:1, representing heterozygous markers in both parents with the same genotypes. The markers segregating 3:1 were used to establish linkage between the testcross markers. The final map comprised of 357 linked markers, including 57 RFLPs, 64 SSRs and 236 AFLPs that were assigned to 131 co-segregation groups, considering a LOD score of 5, and a recombination fraction of 37.5 cM with map distances estimated by Kosambi function. The co-segregation groups represented a total map length of 2,602.4 cM, with a marker density of 7.3 cM. When the same data were analyzed using JoinMap software, only 217 linked markers were assigned to 98 co-segregation groups, spanning 1,340 cM, with a marker density of 6.2 cM. The maximum-likelihood approach reduced the number of unlinked markers to 761 (68.0%), compared to 901 (80.5%) using JoinMap. All the co-segregation groups obtained using JoinMap were present in the map constructed based on the maximum-likelihood method. Differences on the marker order within the co-segregation groups were observed between the two maps. Based on RFLP and SSR markers, 42 of the 131 co-segregation groups were assembled into 12 putative homology groups. Overall, the simultaneous maximum-likelihood estimation of linkage and linkage phases was more efficient than the method used by JoinMap to generate an integrated genetic map of sugarcane.
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