We employed modified substrates as outer heterogeneous catalysts to reduce the soot originating from the incomplete diesel combustion. Here, we proposed that ceria（CeO2）-based catalysts could lower the temperature a...We employed modified substrates as outer heterogeneous catalysts to reduce the soot originating from the incomplete diesel combustion. Here, we proposed that ceria（CeO2）-based catalysts could lower the temperature at which soot combustion occurred from 610 oC to values included in the operation range of diesel exhausts（270–400 oC）. Here, we used the sol-gel method to synthesize catalysts based on mixed oxides（ZnO：CeO2） deposited on cordierite substrates, and modified by ruthenium nanoparticles. The presence of ZnO in these mixed oxides produced defects associated with oxygen vacancies, improving thermal stability, redox potential, sulfur resistance, and oxygen storage. We evaluated the morphological and structural properties of the material by X-ray diffraction（XRD）, Brumauer-emmett-teller method（BET）, temperature programmed reduction（H2-TPR）, scanning electron microscopy（SEM）, and transmission electron microscopy（TEM）. We investigated how the addition of Ru（0.5 wt.%） affected the catalytic activity of ZnO：CeO2 in terms of soot combustion. Thermogravimetric analysis（TG/DTA） revealed that presence of the catalyst decreased the soot combustion temperature by 250 oC, indicating that the oxygen species arose at low temperatures, which was the main reason for the high reactivity of the oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy（DRS） showed that the catalyst containing Ru on the mixed oxide-impregnated cordierite samples efficiently oxidized soot in a diesel stationary motor： soot emission decreased 80%.展开更多
During social interactions,the behavior of an individual often depends on the sex of its social partner.Many animal societies have males and females that play very different behavioral roles,although they coexist and ...During social interactions,the behavior of an individual often depends on the sex of its social partner.Many animal societies have males and females that play very different behavioral roles,although they coexist and interact non-sexually.At specific phases of the colony cycle,social wasp females and males are contemporaries within a nest,they often interact,although mating occurs mostly off the nest,therefore providing an opportunity to test sex discrimination in contexts other than classical sexual ones.We performed a lure presentation experiment to test if Mischocyttarus metathoracicus discriminate between conspecifics of the 2 sexes during on-nest social interactions.Female wasps discriminated conspecific sex during experimentally simulated nest intrusions.Visual and chemical cues may account for this sex discrimination.Despite sex discrimination(evidenced by differential inspective behavior from the nest females toward the female and the male lures),female wasps were as aggressive toward lures of both sexes.In the female-dominated hymenopteran societies,males are often subordinate and not aggressive on nest,resulting in females directing less aggression to them compared to other females.Instead,M.metathoracicus males and females are both aggressive toward nestmates,so they might be perceived as similar threat during on-nest social interactions.展开更多
A high-rate capability carbon-encapsulated polyaniline(PANI)composite is fabricated by a novel electrodeposition method of polyaniline on a carbon nanotube(CNT)forest,grown on carbon paper.This is followed by coating ...A high-rate capability carbon-encapsulated polyaniline(PANI)composite is fabricated by a novel electrodeposition method of polyaniline on a carbon nanotube(CNT)forest,grown on carbon paper.This is followed by coating of an amorphous carbon layer via hydrothermal carbonization(HTC)of glucose,forming a three-layer structure.We demonstrate that a slow scan rate,voltage-restricted electrodeposition process can be used to produce a uniform PANI coating on individual CNTs throughout the network.The CNT forest structure offers excellent electronic and structural connection for the PANI nanofiber network,while the coating of amorphous carbon reduces electrode resistance,promoting enhanced electrochemical performance and reinforced structural stability during charging and discharging.The as-prepared CNT/PANI/HTC composite exhibited a high specific capacitance of 571 F g-1 at 1 A g-1,and 557 F g-1 at 100 A g-1,whilst demonstrating a record rate capability of 98%capacitance retention,when the current density is increased 100-fold.This advanced rate performance indicates that a slow electrodeposition process produces an electrochemically stable three-layer composite with enhanced diffusion kinetics.Hence,the method developed in this work establishes further control on the electrochemical deposition of energy storage materials,for high-rate capability.展开更多
In this work, the role of the disulfide bridges in the maintenance of the secondary structure of the antimicrobial peptides androctonin, poly-phemusin-I, and thanatin is analyzed on the basis of their structural chara...In this work, the role of the disulfide bridges in the maintenance of the secondary structure of the antimicrobial peptides androctonin, poly-phemusin-I, and thanatin is analyzed on the basis of their structural characteristics and of three of their respective mutants, andry4, poly4, and thany2, in which all the cysteine residues have been replaced with tyrosine residues. The absence of the disulfide bridges in andry4, poly4, and thany2 seems to be compensated by an overall enforcement of the original hydrogen bonds and by extra attractive interactions between the aromatic rings of the tyrosine residues. In spite of the mutations, the original β-hairpin structures are maintained in the three mutants, but the best conformational similarities are found for the androctonin/andry4 pair.展开更多
Entomopathogenic fungi, such as Metarhizium anisopliae, are able to control various insect pests. These fungi attack the integument of the host using an enzymatic complex. Among the enzymes found in this complex, chit...Entomopathogenic fungi, such as Metarhizium anisopliae, are able to control various insect pests. These fungi attack the integument of the host using an enzymatic complex. Among the enzymes found in this complex, chitinase is an important component. However, the relation between the chitinase production and the virulence from different M. anisopliae strains has not been analyzed. In this manuscript it is presented the chitinase production by four M. anisopliae strains with different potential of virulence in Solid-State Fermentation using silkworm chrysalis as substrate. The higher chitinase level was obtained with the strain IBCB 360 (7.14 U/g of substrate) with potential virulence of 68% on Diatrea saccharalis. The enzyme production was optimized for all strains using a factorial planning (CCRD) considering the cultivation time and medium humidity as independent variables. The maximal production of chitinase was obtained at a range from 8 to 12-days old cultures and from 45% to 62% of moisture according to the surface response plot, with high R2 value. The enzyme production by the strain IBCB 167 was increased two-folds under optimized conditions, while for the strains IBCB 360 and 425 the chitinase production was increased four-folds and nine-folds for the strain IBCB 384.展开更多
In this paper, a novel solid state Nitric Oxide (NO) sensor made of a spin trap (iron(II)-diethyldithiocarbamate complex, FeDETC) encapsulated in a siloxane-poly(oxypropylene) (PPO) matrix was developed. Nitric oxide ...In this paper, a novel solid state Nitric Oxide (NO) sensor made of a spin trap (iron(II)-diethyldithiocarbamate complex, FeDETC) encapsulated in a siloxane-poly(oxypropylene) (PPO) matrix was developed. Nitric oxide (NO), a free radical molecule, has numerous roles in various physiological functions, such as the regulation of blood pressure, immune response to bacterial infection, and nervous systems. Siloxane-polyether hybrid materials, for example siloxane-poly(oxypropylene) (PPO), are easy to prepare, transparent and flexible. The combination of all these characteristics in a unique material allows it to be used in several scientific and technological areas, including human health. NO radical is trapped in FeDETC, which allows its detection by electron paramagnetic resonance (EPR). FeDETC was added while PPO was a sol, which was then left in air for gelation. The novel sensor was dived directly into a solution of NO, when the NO-FeDETC complex was formed. Our results show that the novel sensor responds to NO, with similar sensitivity as previously published sensors. PPO sensors present a strong EPR signal and a high stability, keeping its signal for 45 days. We have studied ways to accelerate the NO release from the sensor, in order to study its potential as a drug delivery system. We observed an acceleration in NO release by using a modulated magnetic field of 40 G at 100 kHz;as well as by UV irradiation. Thermal induced NO release was also tested by heating NO-FeDETC PPO up to 50°C, with good results.展开更多
In social insects,it has been suggested that reproduction and the production of particular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in pre...In social insects,it has been suggested that reproduction and the production of particular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in predisposing such cues to later evolve into full-fledged queen pheromone signals.However,to date,only few studies have experimentally tested this“hormonal pleiotropy”hypothesis.Here,we formally test this hypothesis using data from four species of Polistine wasps,Polistes dominula,Polistes satan,Mischocyttarus metathoracicus,and Mischocyttarus cassununga,and experimental treatments with JH using the JH analogue methoprene and the anti-JH precocene.In line with reproduction being under JH control,our results show that across these four species,precocene significantly decreased ovary development when compared with both the acetone solvent-only control and the methoprene treatment.Consistent with the hormonal pleiotropy hypothesis,these effects on reproduction were further matched by subtle shifts in the CHC profiles,with univariate analyses showing that in P.dominula and P.satan the abundance of particular linear alkanes and mono-methylated alkanes were affected by ovary development and our hormonal treatments.The results indicate that in primitively eusocial wasps,and particularly in Polistes,reproduction and the production of some CHC cues are under joint JH control.We suggest that pleiotropic links between reproduction and the production of such hydrocarbon cues have been key enablers for the origin of true fertility and queen signals in more derived,advanced eusocial insects.展开更多
Social information is widely used in the animal kingdom and can be highly adaptive.In social insects,foragers can use social information to find food,avoid danger,or choose a new nest site.Copying others allows indivi...Social information is widely used in the animal kingdom and can be highly adaptive.In social insects,foragers can use social information to find food,avoid danger,or choose a new nest site.Copying others allows individuals to obtain information without having to sample the environment.When foragers communicate information they will often only advertise high-quality food sources,thereby filtering out less adaptive information.Stingless bees,a large pantropical group of highly eusocial bees,face intense inter-and intra-specific competition for limited resources,yet display disparate foraging strategies.Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not.Our current understanding of why some species communicate foraging sites while others do not is limited.Studying freely foraging colonies of several co-existing stingless bee species in Brazil,we investigated if recruitment to specific food locations is linked to 1)the sugar content of forage,2)the duration of foraging trips,and 3)the variation in activity of a colony from 1 day to another and the variation in activity in a species over a day.We found that,contrary to our expectations,species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates.Furthermore,foragers from recruiting species did not have shorter foraging trip durations than those from weakly recruiting species.Given the intense inter-and intraspecific competition for resources in these environments,it may be that recruiting species favor food resources that can be monopolized by the colony rather than food sources that offer high-quality rewards.展开更多
BACKGROUND Patients with hepatitis C virus(HCV) and hepatocellular carcinoma(HCC) may or not develop iron overload(IO),which is associated with worst prognosis,because can cause serious damage to organs.HFE gene contr...BACKGROUND Patients with hepatitis C virus(HCV) and hepatocellular carcinoma(HCC) may or not develop iron overload(IO),which is associated with worst prognosis,because can cause serious damage to organs.HFE gene controls the iron uptake from gut,particularly in patients with hereditary hemochromatosis(HH).AIM To identify associations between HFE coding region in patients exhibiting hereditary hemochromatosis and in diseases associated with acquired IO.METHODS We sequenced exons 2 to 5 and boundary introns of HFE gene,evaluating all polymorphic sites in patients presenting hereditary(hemochromatosis) or acquired iron overload HCV and HCC) and in healthy controls,using Sanger sequencing.We also determined the ensemble of extended haplotype in healthy control individuals,including several major histocompatibility complex loci,using sequence specific probes.Haplotype reconstruction was performed using the Arlequin and Phase softwares,and linkage disequilibrium(LD) between histocompatibility loci and HFE gene was performed using the Haploview software.RESULTS The HFE*003 allele was overrepresented(f = 71%) and HFE*001 allele was underrepresented(f = 14%) in HH patients compared to all groups.A strong linkage disequilibrium was observed among the H63 D-G,IVS2(+4)-C and C282 YG gene variants,particularly in HH;however,the mutation IVS2(+4)T>C was not directly associated with HH susceptibility.The HFE*001/HFE*002 genotype conferred susceptibility to HCC in HCV patients exhibiting IO(P = 0.02,OR =14.14).Although HFE is telomeric to other histocompatibility genes,the H63 DG/IVS2(+4)-C(P ≤ 0.00001/P ≤ 0.0057) combination was in LD with HLA-B*44 allele group in healthy controls.No LD was observed between HFE alleles and other major histocompatibility loci.CONCLUSION A differential HFE association was observed for HH and for diseases associated with acquired IO(HCV,HCC).Since HFE is very distant from other histocompatibility loci,only weak associations were observed with these alleles.展开更多
Biology of the aphid Therioaphis maculata was studied on alfalfa （Medicago sativa L.）, including four resistant （Mesa-Sirsa, CUF101, Baker and Lahontan） and two susceptible （ARC and Caliverde） alfalfa cultivars,...Biology of the aphid Therioaphis maculata was studied on alfalfa （Medicago sativa L.）, including four resistant （Mesa-Sirsa, CUF101, Baker and Lahontan） and two susceptible （ARC and Caliverde） alfalfa cultivars, and one of the most cropped Brazilian cultivars, Crioula. Under controlled conditions, antibiosis （i.e., reduced longevity, fecundity and increased mortality of the aphid） was observed mainly on the resistant alfalfa cultivars, except on Lahontan. Crioula seemed to be tolerant to aphids. Present data support geographic limitation usage of cultivars, and we suggest Baker and Mesa-Sirsa as sources of antibiosis, and provide biological information of a tropical T. maculata biotype on alfalfa.展开更多
It is largely known that the range of an insect diet is mostly determined by oviposition behavior, mainly in species with endophytic larvae such as Zabrotes subfasciatus. However, the proximate factors determining hos...It is largely known that the range of an insect diet is mostly determined by oviposition behavior, mainly in species with endophytic larvae such as Zabrotes subfasciatus. However, the proximate factors determining host choice and the subsequent steps leading to the expansion or reduction of the host number and occasional host shifts are largely unknown. We analyzed various factors determining host preference of Z. subfasciatus through the evaluation of： （i） oviposition preference of a wild population of Z. subfasciatus on the usual host （bean） and unusual hosts （lentil, chickpea and soy）, and the performance of the offspring; （ii） artificial selection for increasing preference for hosts initially less frequently chosen; （iii） comparison of oviposition behavior between two different populations （reared for -30 generations in beans or chickpeas, respectively）; （iv） oviposition timing on usual and unusual hosts; and （v） identification of preference hierarchies. We found that when using unusual hosts, there is no correlation between performance and preference and that the preference hierarchy changes only slightly when the population passes through several generations on the less frequently accepted host. We also found a positive response to artificial selection for increasing oviposition on the less preferred host; however, when the host-choice experiment involved two varieties of the usual host, the response was faster than when the choice involved usual and unusual hosts. Finally, beetles reared on an unusual host （chickpea） for 26 generations showed similar good fitness on both usual and unusual hosts, indicating that the use of a new host does not necessarily result in the loss of performance on the original host. Nevertheless, this population showed lower fitness on the usual host than that of the original population, suggesting an underlying partial trade-off phenomenon which may contribute to a broadening of diet of this insect species.展开更多
The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. T...The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.展开更多
The effects of competition on populations of the bean weevil Zabrotes sub- fasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaini...The effects of competition on populations of the bean weevil Zabrotes sub- fasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaining the number of couples （6） and varying the amount of available host seeds： HC, high （limited availability of host： 1.35 g）; IC, intermediate （intermediate availability of host： 6 g）; and LC, low competition （abun- dance of host： 36 g）. It was found that the distribution of the eggs laid on grains was different among treatments： in LC, for example, although females showed high fecundity （35.4 ± 5.6 eggs/female） the number of eggs laid on each grain was small （1.2 ± 0.4 eggs on each seed）, thus avoiding larval competition of their offspring; whereas in HC treatment, females showed low fecundity （27.04 ± 4.5 eggs/female） but laid many eggs on each grain （15.03 ± 4.3 eggs）. There were no changes in the ability to respond to different amounts of host via oviposition behavior （egg distribution） during 41 generations. How- ever, HC females had more offspring than LC females under HC conditions. This suggests that HC insects evolved toward higher fitness in crowded conditions. In addition, after inverting the competition level, insects behaved independently of the treatment conditions they experienced through generations, thus showing that oviposition behavior is flexible. Taken together, our results show that Z. subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.展开更多
Understanding of resource requirements of vulnerable species is key for conservation planning.Here,we used sta-ble carbon(δ13C)and nitrogen isotopes(δ15N)of hair from giant armadillos(Priodontes maximus)to understan...Understanding of resource requirements of vulnerable species is key for conservation planning.Here,we used sta-ble carbon(δ13C)and nitrogen isotopes(δ15N)of hair from giant armadillos(Priodontes maximus)to understand individual resource use.We collected hair from 19 giant armadillos analyzing 34 samples from the Brazilian Pan-tanal and compared the resource use between sexes and age classes.We also assessed the relationship of isotopic values with individuals’body mass and the habitat type used.We observed a wide variation in resource use by giant armadillos,showing that individuals consume prey that feeds on distinct resources and occupies different habitat types,indicating that there is individual variation in foraging behavior.Most giant armadillos presented a mixed diet(C3/C4 resources,forests/open areas),but a quarter of individuals had strictly C4 diets(open areas).Males are more prone to forage on C4 resources,presenting an isotopic niche 2.6-times larger than that of females.Subadults presented diets more associated with habitats with high arboreal cover(C3 resources,forests),while adults foraged more in open areas(C4 resources).This result is mirrored by the positive relationship betweenδ13C values and body mass,suggesting that larger giant armadillos tend to feed more in open areas.We observed thatδ13C values decreased as individuals increased the use of habitats with high arboreal cover.We stress the importance of con-serving the natural mosaic in the Pantanal landscape for the species persistence,given that giant armadillos require all habitat types to fulfill their dietary,spatial,and developmental needs.展开更多
基金Project supported by the National Council for Scientific and Technological Development(CNPq)(105477/2012-5)
文摘We employed modified substrates as outer heterogeneous catalysts to reduce the soot originating from the incomplete diesel combustion. Here, we proposed that ceria（CeO2）-based catalysts could lower the temperature at which soot combustion occurred from 610 oC to values included in the operation range of diesel exhausts（270–400 oC）. Here, we used the sol-gel method to synthesize catalysts based on mixed oxides（ZnO：CeO2） deposited on cordierite substrates, and modified by ruthenium nanoparticles. The presence of ZnO in these mixed oxides produced defects associated with oxygen vacancies, improving thermal stability, redox potential, sulfur resistance, and oxygen storage. We evaluated the morphological and structural properties of the material by X-ray diffraction（XRD）, Brumauer-emmett-teller method（BET）, temperature programmed reduction（H2-TPR）, scanning electron microscopy（SEM）, and transmission electron microscopy（TEM）. We investigated how the addition of Ru（0.5 wt.%） affected the catalytic activity of ZnO：CeO2 in terms of soot combustion. Thermogravimetric analysis（TG/DTA） revealed that presence of the catalyst decreased the soot combustion temperature by 250 oC, indicating that the oxygen species arose at low temperatures, which was the main reason for the high reactivity of the oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy（DRS） showed that the catalyst containing Ru on the mixed oxide-impregnated cordierite samples efficiently oxidized soot in a diesel stationary motor： soot emission decreased 80%.
基金This study was supported by Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior--Brasil(CAPES)--Finance Code 001(to A.R.S.),Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(proccess:142285/2018-8 to A.P.)Fundagao de Amparo a Pesquisa do Estado de Sao Paulo(FAPESP)(proccess:2020/14464-2 to A.R.S.,2019/08029-4 to W.F.,2018/10996-0 to F.N.).
文摘During social interactions,the behavior of an individual often depends on the sex of its social partner.Many animal societies have males and females that play very different behavioral roles,although they coexist and interact non-sexually.At specific phases of the colony cycle,social wasp females and males are contemporaries within a nest,they often interact,although mating occurs mostly off the nest,therefore providing an opportunity to test sex discrimination in contexts other than classical sexual ones.We performed a lure presentation experiment to test if Mischocyttarus metathoracicus discriminate between conspecifics of the 2 sexes during on-nest social interactions.Female wasps discriminated conspecific sex during experimentally simulated nest intrusions.Visual and chemical cues may account for this sex discrimination.Despite sex discrimination(evidenced by differential inspective behavior from the nest females toward the female and the male lures),female wasps were as aggressive toward lures of both sexes.In the female-dominated hymenopteran societies,males are often subordinate and not aggressive on nest,resulting in females directing less aggression to them compared to other females.Instead,M.metathoracicus males and females are both aggressive toward nestmates,so they might be perceived as similar threat during on-nest social interactions.
基金the UK Engineering and Physical Sciences Research Council(EPSRC)for funding this work under the Doctoral Training Partnership(DTP)award(EP/N509772/1)the Sao Paulo Research Foundation FAPESP(grant numbers 2017/04759-2 and 2017/50380-5)+1 种基金financial support from EPSRC(EP/L02263x/1)the Brazilian Government FAPESP SPRINT Program in the conduct of this work
文摘A high-rate capability carbon-encapsulated polyaniline(PANI)composite is fabricated by a novel electrodeposition method of polyaniline on a carbon nanotube(CNT)forest,grown on carbon paper.This is followed by coating of an amorphous carbon layer via hydrothermal carbonization(HTC)of glucose,forming a three-layer structure.We demonstrate that a slow scan rate,voltage-restricted electrodeposition process can be used to produce a uniform PANI coating on individual CNTs throughout the network.The CNT forest structure offers excellent electronic and structural connection for the PANI nanofiber network,while the coating of amorphous carbon reduces electrode resistance,promoting enhanced electrochemical performance and reinforced structural stability during charging and discharging.The as-prepared CNT/PANI/HTC composite exhibited a high specific capacitance of 571 F g-1 at 1 A g-1,and 557 F g-1 at 100 A g-1,whilst demonstrating a record rate capability of 98%capacitance retention,when the current density is increased 100-fold.This advanced rate performance indicates that a slow electrodeposition process produces an electrochemically stable three-layer composite with enhanced diffusion kinetics.Hence,the method developed in this work establishes further control on the electrochemical deposition of energy storage materials,for high-rate capability.
基金Fundacao de Amparo a Pesquisa do Estado de Sao Paulo(FAPESP)for financial support.
文摘In this work, the role of the disulfide bridges in the maintenance of the secondary structure of the antimicrobial peptides androctonin, poly-phemusin-I, and thanatin is analyzed on the basis of their structural characteristics and of three of their respective mutants, andry4, poly4, and thany2, in which all the cysteine residues have been replaced with tyrosine residues. The absence of the disulfide bridges in andry4, poly4, and thany2 seems to be compensated by an overall enforcement of the original hydrogen bonds and by extra attractive interactions between the aromatic rings of the tyrosine residues. In spite of the mutations, the original β-hairpin structures are maintained in the three mutants, but the best conformational similarities are found for the androctonin/andry4 pair.
基金supported by Fundacao de Apoio a Pesquisa do Estado de Sao Paulo(FAPESP)and Coor-denadoria de Apoio ao Ensino Superior(CAPES).
文摘Entomopathogenic fungi, such as Metarhizium anisopliae, are able to control various insect pests. These fungi attack the integument of the host using an enzymatic complex. Among the enzymes found in this complex, chitinase is an important component. However, the relation between the chitinase production and the virulence from different M. anisopliae strains has not been analyzed. In this manuscript it is presented the chitinase production by four M. anisopliae strains with different potential of virulence in Solid-State Fermentation using silkworm chrysalis as substrate. The higher chitinase level was obtained with the strain IBCB 360 (7.14 U/g of substrate) with potential virulence of 68% on Diatrea saccharalis. The enzyme production was optimized for all strains using a factorial planning (CCRD) considering the cultivation time and medium humidity as independent variables. The maximal production of chitinase was obtained at a range from 8 to 12-days old cultures and from 45% to 62% of moisture according to the surface response plot, with high R2 value. The enzyme production by the strain IBCB 167 was increased two-folds under optimized conditions, while for the strains IBCB 360 and 425 the chitinase production was increased four-folds and nine-folds for the strain IBCB 384.
基金This work received financial support from FAPESP,CNPq and CAPES.
文摘In this paper, a novel solid state Nitric Oxide (NO) sensor made of a spin trap (iron(II)-diethyldithiocarbamate complex, FeDETC) encapsulated in a siloxane-poly(oxypropylene) (PPO) matrix was developed. Nitric oxide (NO), a free radical molecule, has numerous roles in various physiological functions, such as the regulation of blood pressure, immune response to bacterial infection, and nervous systems. Siloxane-polyether hybrid materials, for example siloxane-poly(oxypropylene) (PPO), are easy to prepare, transparent and flexible. The combination of all these characteristics in a unique material allows it to be used in several scientific and technological areas, including human health. NO radical is trapped in FeDETC, which allows its detection by electron paramagnetic resonance (EPR). FeDETC was added while PPO was a sol, which was then left in air for gelation. The novel sensor was dived directly into a solution of NO, when the NO-FeDETC complex was formed. Our results show that the novel sensor responds to NO, with similar sensitivity as previously published sensors. PPO sensors present a strong EPR signal and a high stability, keeping its signal for 45 days. We have studied ways to accelerate the NO release from the sensor, in order to study its potential as a drug delivery system. We observed an acceleration in NO release by using a modulated magnetic field of 40 G at 100 kHz;as well as by UV irradiation. Thermal induced NO release was also tested by heating NO-FeDETC PPO up to 50°C, with good results.
基金This research was funded by the Research Foundation Flanders to C.A.O.(postdoctoral fellowship FWO-12V6318N,international mobility grant FWO V449117N and research grant 1513219N)R.C.d.S.was funded by the S~ao Paulo Research Foundation(FAPESP)under the grant 2018/22461-3 and Coordenac¸~ao de Aperfeic¸oamento de Pessoal de Nı´vel Superior,Brasil(CAPES),Finance Code 001+1 种基金C.A.O.,H.M.F.,and T.W.were funded by the research grant(FWO-G064120N)All authors were funded by Bilateral grant FWO-FAPESP(FWO GOF8319N and FAPESP 2018/10996-0)。
文摘In social insects,it has been suggested that reproduction and the production of particular fertilitylinked cuticular hydrocarbons(CHC)may be under shared juvenile hormone(JH)control,and this could have been key in predisposing such cues to later evolve into full-fledged queen pheromone signals.However,to date,only few studies have experimentally tested this“hormonal pleiotropy”hypothesis.Here,we formally test this hypothesis using data from four species of Polistine wasps,Polistes dominula,Polistes satan,Mischocyttarus metathoracicus,and Mischocyttarus cassununga,and experimental treatments with JH using the JH analogue methoprene and the anti-JH precocene.In line with reproduction being under JH control,our results show that across these four species,precocene significantly decreased ovary development when compared with both the acetone solvent-only control and the methoprene treatment.Consistent with the hormonal pleiotropy hypothesis,these effects on reproduction were further matched by subtle shifts in the CHC profiles,with univariate analyses showing that in P.dominula and P.satan the abundance of particular linear alkanes and mono-methylated alkanes were affected by ovary development and our hormonal treatments.The results indicate that in primitively eusocial wasps,and particularly in Polistes,reproduction and the production of some CHC cues are under joint JH control.We suggest that pleiotropic links between reproduction and the production of such hydrocarbon cues have been key enablers for the origin of true fertility and queen signals in more derived,advanced eusocial insects.
基金This study was funded by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[FAPESP,Process No.:2015/24617-2]the Swiss National Science Foundation Ambizione fellowship awarded to C.G.[grant no.PZOOP3_142628/1].
文摘Social information is widely used in the animal kingdom and can be highly adaptive.In social insects,foragers can use social information to find food,avoid danger,or choose a new nest site.Copying others allows individuals to obtain information without having to sample the environment.When foragers communicate information they will often only advertise high-quality food sources,thereby filtering out less adaptive information.Stingless bees,a large pantropical group of highly eusocial bees,face intense inter-and intra-specific competition for limited resources,yet display disparate foraging strategies.Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not.Our current understanding of why some species communicate foraging sites while others do not is limited.Studying freely foraging colonies of several co-existing stingless bee species in Brazil,we investigated if recruitment to specific food locations is linked to 1)the sugar content of forage,2)the duration of foraging trips,and 3)the variation in activity of a colony from 1 day to another and the variation in activity in a species over a day.We found that,contrary to our expectations,species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates.Furthermore,foragers from recruiting species did not have shorter foraging trip durations than those from weakly recruiting species.Given the intense inter-and intraspecific competition for resources in these environments,it may be that recruiting species favor food resources that can be monopolized by the colony rather than food sources that offer high-quality rewards.
基金"Conselho Nacional de Desenvolvimento Cientifico e Tecnologico"(CNPq,Brazil),No.304931/2014-1 and No.148638/2010-4
文摘BACKGROUND Patients with hepatitis C virus(HCV) and hepatocellular carcinoma(HCC) may or not develop iron overload(IO),which is associated with worst prognosis,because can cause serious damage to organs.HFE gene controls the iron uptake from gut,particularly in patients with hereditary hemochromatosis(HH).AIM To identify associations between HFE coding region in patients exhibiting hereditary hemochromatosis and in diseases associated with acquired IO.METHODS We sequenced exons 2 to 5 and boundary introns of HFE gene,evaluating all polymorphic sites in patients presenting hereditary(hemochromatosis) or acquired iron overload HCV and HCC) and in healthy controls,using Sanger sequencing.We also determined the ensemble of extended haplotype in healthy control individuals,including several major histocompatibility complex loci,using sequence specific probes.Haplotype reconstruction was performed using the Arlequin and Phase softwares,and linkage disequilibrium(LD) between histocompatibility loci and HFE gene was performed using the Haploview software.RESULTS The HFE*003 allele was overrepresented(f = 71%) and HFE*001 allele was underrepresented(f = 14%) in HH patients compared to all groups.A strong linkage disequilibrium was observed among the H63 D-G,IVS2(+4)-C and C282 YG gene variants,particularly in HH;however,the mutation IVS2(+4)T>C was not directly associated with HH susceptibility.The HFE*001/HFE*002 genotype conferred susceptibility to HCC in HCV patients exhibiting IO(P = 0.02,OR =14.14).Although HFE is telomeric to other histocompatibility genes,the H63 DG/IVS2(+4)-C(P ≤ 0.00001/P ≤ 0.0057) combination was in LD with HLA-B*44 allele group in healthy controls.No LD was observed between HFE alleles and other major histocompatibility loci.CONCLUSION A differential HFE association was observed for HH and for diseases associated with acquired IO(HCV,HCC).Since HFE is very distant from other histocompatibility loci,only weak associations were observed with these alleles.
文摘Biology of the aphid Therioaphis maculata was studied on alfalfa （Medicago sativa L.）, including four resistant （Mesa-Sirsa, CUF101, Baker and Lahontan） and two susceptible （ARC and Caliverde） alfalfa cultivars, and one of the most cropped Brazilian cultivars, Crioula. Under controlled conditions, antibiosis （i.e., reduced longevity, fecundity and increased mortality of the aphid） was observed mainly on the resistant alfalfa cultivars, except on Lahontan. Crioula seemed to be tolerant to aphids. Present data support geographic limitation usage of cultivars, and we suggest Baker and Mesa-Sirsa as sources of antibiosis, and provide biological information of a tropical T. maculata biotype on alfalfa.
文摘It is largely known that the range of an insect diet is mostly determined by oviposition behavior, mainly in species with endophytic larvae such as Zabrotes subfasciatus. However, the proximate factors determining host choice and the subsequent steps leading to the expansion or reduction of the host number and occasional host shifts are largely unknown. We analyzed various factors determining host preference of Z. subfasciatus through the evaluation of： （i） oviposition preference of a wild population of Z. subfasciatus on the usual host （bean） and unusual hosts （lentil, chickpea and soy）, and the performance of the offspring; （ii） artificial selection for increasing preference for hosts initially less frequently chosen; （iii） comparison of oviposition behavior between two different populations （reared for -30 generations in beans or chickpeas, respectively）; （iv） oviposition timing on usual and unusual hosts; and （v） identification of preference hierarchies. We found that when using unusual hosts, there is no correlation between performance and preference and that the preference hierarchy changes only slightly when the population passes through several generations on the less frequently accepted host. We also found a positive response to artificial selection for increasing oviposition on the less preferred host; however, when the host-choice experiment involved two varieties of the usual host, the response was faster than when the choice involved usual and unusual hosts. Finally, beetles reared on an unusual host （chickpea） for 26 generations showed similar good fitness on both usual and unusual hosts, indicating that the use of a new host does not necessarily result in the loss of performance on the original host. Nevertheless, this population showed lower fitness on the usual host than that of the original population, suggesting an underlying partial trade-off phenomenon which may contribute to a broadening of diet of this insect species.
基金Supported by grants from Fundao de Amparo à Pesquisa no Estado de So Paulo – Brazil(FAPESP no. 06/54431-9)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) – Brazil. CPG Calixto was supported by a fellowship from FAPESP.
文摘The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.
文摘The effects of competition on populations of the bean weevil Zabrotes sub- fasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaining the number of couples （6） and varying the amount of available host seeds： HC, high （limited availability of host： 1.35 g）; IC, intermediate （intermediate availability of host： 6 g）; and LC, low competition （abun- dance of host： 36 g）. It was found that the distribution of the eggs laid on grains was different among treatments： in LC, for example, although females showed high fecundity （35.4 ± 5.6 eggs/female） the number of eggs laid on each grain was small （1.2 ± 0.4 eggs on each seed）, thus avoiding larval competition of their offspring; whereas in HC treatment, females showed low fecundity （27.04 ± 4.5 eggs/female） but laid many eggs on each grain （15.03 ± 4.3 eggs）. There were no changes in the ability to respond to different amounts of host via oviposition behavior （egg distribution） during 41 generations. How- ever, HC females had more offspring than LC females under HC conditions. This suggests that HC insects evolved toward higher fitness in crowded conditions. In addition, after inverting the competition level, insects behaved independently of the treatment conditions they experienced through generations, thus showing that oviposition behavior is flexible. Taken together, our results show that Z. subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.
基金the National Council of Technological and Scientific Development(CNPq)for the research productivity fellowship grant(#308632/2018-4).
文摘Understanding of resource requirements of vulnerable species is key for conservation planning.Here,we used sta-ble carbon(δ13C)and nitrogen isotopes(δ15N)of hair from giant armadillos(Priodontes maximus)to understand individual resource use.We collected hair from 19 giant armadillos analyzing 34 samples from the Brazilian Pan-tanal and compared the resource use between sexes and age classes.We also assessed the relationship of isotopic values with individuals’body mass and the habitat type used.We observed a wide variation in resource use by giant armadillos,showing that individuals consume prey that feeds on distinct resources and occupies different habitat types,indicating that there is individual variation in foraging behavior.Most giant armadillos presented a mixed diet(C3/C4 resources,forests/open areas),but a quarter of individuals had strictly C4 diets(open areas).Males are more prone to forage on C4 resources,presenting an isotopic niche 2.6-times larger than that of females.Subadults presented diets more associated with habitats with high arboreal cover(C3 resources,forests),while adults foraged more in open areas(C4 resources).This result is mirrored by the positive relationship betweenδ13C values and body mass,suggesting that larger giant armadillos tend to feed more in open areas.We observed thatδ13C values decreased as individuals increased the use of habitats with high arboreal cover.We stress the importance of con-serving the natural mosaic in the Pantanal landscape for the species persistence,given that giant armadillos require all habitat types to fulfill their dietary,spatial,and developmental needs.
