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1.
Int J Mol Sci ; 22(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34639230

RESUMO

The cystine knot protein Spätzle is a Toll receptor ligand that modulates the intracellular signaling cascade involved in the nuclear factor kappa B (NF-κB)-mediated regulation of antimicrobial peptide (AMP)-encoding genes. Spätzle-mediated activation of the Toll pathway is critical for the innate immune responses of insects against Gram-positive bacteria and fungi. In this study, the open reading frame (ORF) sequence of Spätzle-like from T. molitor (TmSpz-like) identified from the RNA sequencing dataset was cloned and sequenced. The 885-bp TmSpz-like ORF encoded a polypeptide of 294 amino acid residues. TmSpz-like comprised a cystine knot domain with six conserved cysteine residues that formed three disulfide bonds. Additionally, TmSpz-like exhibited the highest amino acid sequence similarity with T. castaneum Spätzle (TcSpz). In the phylogenetic tree, TmSpz-like and TcSpz were located within a single cluster. The expression of TmSpz-like was upregulated in the Malpighian tubules and gut tissues of T. molitor. Additionally, the expression of TmSpz-like in the whole body and gut of the larvae was upregulated at 24 h post-E. coli infection. The results of RNA interference experiments revealed that TmSpz-like is critical for the viability of E. coli-infected T. molitor larvae. Eleven AMP-encoding genes were downregulated in the E. coli-infected TmSpz-like knockdown larvae, which suggested that TmSpz-like positively regulated these genes. Additionally, the NF-κB-encoding genes (TmDorX1, TmDorX2, and TmRelish) were downregulated in the E. coli-infected TmSpz-like knockdown larvae. Thus, TmSpz-like plays a critical role in the regulation of AMP production in T. molitor in response to E. coli infection.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Infecções por Escherichia coli/microbiologia , Escherichia coli/imunologia , Imunidade Inata/imunologia , Proteínas de Insetos/metabolismo , Staphylococcus aureus/imunologia , Tenebrio/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Insetos/genética , Larva/genética , Larva/imunologia , Larva/metabolismo , Larva/microbiologia , Filogenia , Homologia de Sequência de Aminoácidos , Infecções Estafilocócicas , Tenebrio/genética , Tenebrio/metabolismo , Tenebrio/microbiologia
2.
Artigo em Inglês | MEDLINE | ID: mdl-34494946

RESUMO

Six yeast isolates were obtained from rotting wood samples in Brazil and frass of a cerambycid beetle larva in French Guiana. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the isolates represent a novel species of Cyberlindnera. This novel species is related to Cyberlindnera japonica, Cyberlindnera xylosilytica, Candida easanensis and Candida maesa. It is heterothallic and produces asci with two or four hat-shaped ascospores. The name Cyberlindnera dasilvae sp. nov. is proposed to accommodate the novel species. The holotype of Cy. dasilvae is CBS 16129T and the designated paratype is CBS 16584. The MycoBank number is 838252. All isolates of Cy. dasilvae were able to convert xylose into xylitol with maximum xylitol production within 60 and 72 h. The isolates produced xylitol with values ranging from 12.61 to 31.79 g l-1 in yeast extract-peptone-xylose medium with 5% xylose. When the isolates were tested in sugarcane bagasse hydrolysate containing around 35-38 g l-1d-xylose, isolate UFMG-CM-Y519 showed maximum xylitol production.


Assuntos
Besouros/microbiologia , Filogenia , Saccharomycetales/classificação , Madeira , Xilitol , Animais , DNA Fúngico/genética , DNA Espaçador Ribossômico , Fezes/microbiologia , Larva/microbiologia , Técnicas de Tipagem Micológica , Saccharomycetales/isolamento & purificação , Análise de Sequência de DNA , Madeira/microbiologia , Xilitol/metabolismo
3.
J Insect Physiol ; 134: 104308, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34474015

RESUMO

The microbiota influences hosts' health and fitness. However, the extent to which the microbiota affects host' foraging decisions and related life history traits remains to be fully understood. Our study explored the effects of microbiota manipulation on foraging preference and phenotypic traits of larval and adult stages of the polyphagous fruit fly Bactrocera tryoni, one of the main horticultural pests in Australia. We generated three treatments: control (non-treated microbiota), axenic (removed microbiota), and reinoculation (individuals which had their microbiota removed then re-introduced). Our results confirmed that axenic larvae and immature (i.e., newly emerged 0 day-old, sexually-immature) adults were lighter than control and reinoculated individuals. Interestingly, we found a sex-specific effect of the microbiota manipulation on carbohydrate intake and body composition of 10 day-old mature adults. Axenic males ate less carbohydrate, and had lower body weight and total body fat relative to control and reinoculated males. Conversely, axenic females ate more carbohydrate than control and reinoculated ones, although body weight and lipid reserves were similar across treatments. Axenic females produced fewer eggs than control and reinoculated females. Our findings corroborate the far-reaching effects of microbiota in insects found in previous studies and show, for the first time, a sex-specific effect of microbiota on feeding behaviour in flies. Our results underscore the dynamic relationship between the microbiota and the host with the reinoculation of microbes restoring some traits that were affected in axenic individuals.


Assuntos
Composição Corporal , Comportamento Alimentar/fisiologia , Fatores Sexuais , Tephritidae , Animais , Metabolismo dos Carboidratos , Dípteros/microbiologia , Dípteros/fisiologia , Feminino , Fertilidade , Microbioma Gastrointestinal , Interações entre Hospedeiro e Microrganismos , Larva/microbiologia , Larva/fisiologia , Masculino , Tephritidae/microbiologia , Tephritidae/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-34379580

RESUMO

Taxonomic positions of four Gram-negative bacterial strains, which were isolated from larvae of two insects in Jeju, Republic of Korea, were determined by a polyphasic approach. Strains CWB-B4, CWB-B41 and CWB-B43 were recovered from larvae of Protaetia brevitarsis seulensis, whereas strain BWR-B9T was from larvae of Allomyrina dichotoma. All the isolates grew at 10-37 °C, at pH 5.0-9.0 and in the presence of 4 % (w/v) NaCl. The 16S rRNA gene phylogeny showed that the four isolates formed two distinct sublines within the order Enterobacteriales and closely associated with members of the genus Jinshanibacter. The first group represented by strain CWB-B4 formed a tight cluster with Jinshanibacter xujianqingii CF-1111T (99.3 % sequence similarity), whereas strain BWR-B9T was most closely related to Jinshanibacter zhutongyuii CF-458T (99.5 % sequence similarity). The 92 core gene analysis showed that the isolates belonged to the family Budviciaceae and supported the clustering shown in 16S rRNA gene phylogeny. The genomic DNA G+C content of the isolates was 45.2 mol%. A combination of overall genomic relatedness and phenotypic distinctness supported that three isolates from Protaetia brevitarsis seulensis are different strains of Jinshanibacter xujianqingii, whereas one isolate from Allomyrina dichotoma represents a new species of the genus Jinshanibacter. On the basis of results obtained here, Jinshanibacter allomyrinae sp. nov. (type strain BWR-B9T=KACC 22153T=NBRC 114879T) and Insectihabitans xujianqingii gen. nov., comb. nov. are proposed, with the emended descriptions of the genera Jinshanibacter, Limnobaculum and Pragia.


Assuntos
Besouros/microbiologia , Gammaproteobacteria/classificação , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Gammaproteobacteria/isolamento & purificação , Larva/microbiologia , Fosfolipídeos/química , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA
5.
Neotrop Entomol ; 50(5): 804-811, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34398398

RESUMO

Bacillus thuringiensis (Bt)-based bioinsecticides and transgenic plants expressing proteins with insecticidal activity (Cry and Vip) have been successfully used in several integrated pest management programs worldwide. Lepidoptera comprise some of the most economically important insect pests of the major agricultural crops. In this study, the toxicity of 150 Bt strains was evaluated against Helicoverpa armigera (Hübner) larvae. Eight strains (426, 520B, 1636, 1641, 1644, 1648, 1657 and 1658) showed high insecticide activity against H. armigera and were therefore tested against Anticarsia gemmatalis (Hübner), Spodoptera cosmioides (Walker), Chrysodeixis includens (Walker), and Diatraea saccharalis (Fabricius) larvae. Our results showed that most of the Bt strains were also toxic to these lepidopteran species. The biochemical and molecular analyses of these strains revealed that they had a similar protein profile; however, their cry and vip gene contents were variable. In addition, the median lethal concentration (LC50) of the selected strains indicated that the strains 1636, 1641, and 1658 were the most effective against H. armigera, showing LC50 values of 185.02, 159.44, and 192.98 ng/cm2, respectively. Our results suggest that the selected Bt strains have great potential to control the lepidopteran pests H. armigera, A. gemmatalis, D. saccharalis, S. cosmioides, and C. includes.


Assuntos
Bacillus thuringiensis , Agentes de Controle Biológico , Mariposas , Controle Biológico de Vetores , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias , Endotoxinas/toxicidade , Proteínas Hemolisinas , Larva/microbiologia , Mariposas/microbiologia
6.
Ticks Tick Borne Dis ; 12(6): 101809, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34454337

RESUMO

Francisella tularensis subsp. holarctica is the causative agent of tularaemia in Europe. Finland is a high-incidence region for tularaemia, with mosquito bites as the most common sources of infection. However, in Central and Western Europe, ticks (Acari: Ixodidae) have been suggested as the main vectors. Indeed, several studies have reported the pathogen from the locally most common human-biting tick species, Ixodes ricinus. In Finland, the occurrence of the pathogen in ticks has started receiving attention only recently. Here, we collate previous tick screening data from Finland regarding F. tularensis as well as present the results from a novel screening of roughly 15 000 I. ricinus and I. persulcatus collected from across the country. In total, 14 878 ticks collected between 2015 and 2020 were screened for F. tularensis using a TaqMan-based qPCR assay targeting the 23 KDa gene. The combined screening efforts of the current and previous studies, encompassing roughly 20 000 ticks, did not find any positive ticks. Given the negative results despite the considerable sample size, it appears that the pathogen is not circulating in local tick populations in Finland. We discuss some possible reasons for the lack of the bacterium in ticks in this high-incidence region of tularaemia.


Assuntos
Francisella/isolamento & purificação , Ixodes/microbiologia , Animais , Finlândia , Ixodes/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/microbiologia , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Especificidade da Espécie , Tularemia/microbiologia
7.
Arch Insect Biochem Physiol ; 108(2): e21834, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34288075

RESUMO

The Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), is a major pest of potato plants worldwide and is notorious for its ability to develop resistance to insecticides. Cry3 toxins synthesized by Bacillus thuringiensis ssp. tenebrionis have been used successfully to manage this pest. Resistance to Cry toxins is a concerning problem for many insect pests; therefore, it is important to determine the mechanisms by which insects acquire resistance to these toxins. Cadherin-like and ABC transporter proteins have been implicated in the mode of action of Cry toxins as mutations in these genes render lepidopterans resistant to them; however, clear consensus does not exist on whether these proteins also play a role in Cry3 toxin activity and/or development of resistance in coleopterans. In the current study, we identified the L. decemlineata orthologues of the cadherin (LdCAD) and the ABCB transporter (LdABCB1) that have been implicated in the mode of action of Cry toxins in other coleopterans. Suppression of LdABCB1 via RNA interference reduced toxin-related larval mortality, whereas partial silencing of LdCAD did not. Our results suggest that the ABCB is involved in the mode of action of Cry3Aa toxins; however, no evidence was found to support the role of cadherin as a receptor of Cry3Aa in L. decemlineata.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Toxinas de Bacillus thuringiensis/farmacologia , Besouros , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Resistência a Inseticidas/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Caderinas/genética , Caderinas/metabolismo , Besouros/efeitos dos fármacos , Besouros/metabolismo , Besouros/microbiologia , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Inseticidas/metabolismo , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/metabolismo , Larva/microbiologia , Controle Biológico de Vetores , Interferência de RNA
8.
Ticks Tick Borne Dis ; 12(5): 101773, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34229999

RESUMO

Understanding the abiotic and biotic variables affecting tick populations is essential for studying the biology and health risks associated with vector species. We conducted a study on the phenology of exotic Haemaphysalis longicornis (Asian longhorned tick) at a site in Albemarle County, Virginia, United States. We also assessed the importance of wildlife hosts, habitats, and microclimate variables such as temperature, relative humidity, and wind speed on this exotic tick's presence and abundance. In addition, we determined the prevalence of infection with selected tick-borne pathogens in host-seeking H. longicornis. We determined that the seasonal activity of H. longicornis in Virginia was slightly different from previous studies in the northeastern United States. We observed nymphal ticks persist year-round but were most active in the spring, followed by a peak in adult activity in the summer and larval activity in the fall. We also observed a lower probability of collecting host-seeking H. longicornis in field habitats and the summer months. In addition, we detected H. longicornis on several wildlife hosts, including coyote (Canis latrans), eastern cottontail (Sylvilagus floridanus), raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), white-tailed deer (Odocoileus virginianus), woodchuck (Marmota monax), and a Peromyscus sp. mouse. This latter record is the first detection of a larval H. longicornis on a North American rodent host important to the enzootic maintenance of tick-borne pathogens of humans and animals. Finally, we continued to detect the exotic piroplasm parasite, Theileria orientalis Ikeda, in H. longicornis as well as other pathogens, including Rickettsia felis, Anaplasma phagocytophilum (AP-1), and a Hepatozoon sp. previously characterized in Amblyomma americanum. These represent some of the first detections of arthropod-borne pathogens native to the United States in host-seeking H. longicornis. These data increase our understanding of H. longicornis biology in the United States and provide valuable information into the future health risks associated with this tick and pathogens.


Assuntos
Ecossistema , Interações Hospedeiro-Parasita , Interações Hospedeiro-Patógeno , Ixodidae , Animais , Feminino , Ixodidae/crescimento & desenvolvimento , Ixodidae/microbiologia , Ixodidae/parasitologia , Ixodidae/fisiologia , Larva/crescimento & desenvolvimento , Larva/microbiologia , Larva/parasitologia , Larva/fisiologia , Masculino , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Ninfa/parasitologia , Ninfa/fisiologia , Estações do Ano , Virginia
9.
Sci Rep ; 11(1): 13915, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34230511

RESUMO

Beauveria bassiana is one of the most widely studied and used entomopathogenic fungus as biopesticide. In the biological control of pests, B. bassiana will persist in the soil after application, and will inevitably contact with earthworms, especially the epigeic earthworm species. So, what are the effects of earthworm and its epidermal mucus on the activity of B. bassiana? We employed the epigeic earthworm Eisenia fetida, B. bassiana TST05 strain, and the insect Atrijuglans hetaohei mature larvae to study the impact of earthworm epidermal mucus on the vitality and pathogenicity of B. bassiana to insect. Methods included scanning electron microscope observation, detection of spore germination, fungal extracellular enzyme activity, and infection testing to A. hetaohei. The results showed that the B. bassiana spores may attach to the cuticle of E. fetida but they could be covered by the epidermal mucus and became rough and shrunken. After treatment with the epidermal mucus, the spore germination and extracellular enzymes of B. bassiana was significantly inhibited. Inoculation of A. hetaohei larvae with a mixture of B. bassiana and mucus showed that the mucus could reduce the pathogenicity of B. bassiana to the insect, resulting in a slower disease course and lower mortality. It was concluded that the epidermal mucus of the earthworm E. fetida can inhibit the activity of B. bassiana, as well as the infectivity and pathogenicity of fungus to target insects. However, after treatment with epidermal mucus the surviving B. bassiana still had certain infectivity to insects. This is of great significance for the application of B. bassiana in biological control of pests.


Assuntos
Beauveria/patogenicidade , Epiderme/química , Muco/química , Oligoquetos/química , Animais , Beauveria/crescimento & desenvolvimento , Beauveria/ultraestrutura , Espaço Extracelular/enzimologia , Larva/microbiologia , Esporos Fúngicos/fisiologia
10.
PLoS One ; 16(7): e0255029, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34297754

RESUMO

Entomopathogenic fungi are regarded as effective biocontrol agents in pest management. Different fungi isolates exhibit varying degree of pathogenicity against red palm weevil [Rhynchophorus ferrugineus (Olivier)]. The pathogenicity of four native isolate from Saudi Arabia (three Beauveria bassiana named as BbSA-1, BbSA-2, BbSA-3 and one Metarhizium anisopliae regarded as MaSA-1) and three exotic isolates from Indonesia (B. bassiana coded as BbIDN-1 and M. anisopliae named as MaIDN-1 and MaIDN-2) was evaluated against red palm weevil under laboratory conditions. The isolates were applied to eggs (1 day old), larvae (3 and 35 days old), pupae (5 days old) and adults (10 days old). The average mortality rate of eggs and hatched larvae was 100% in all of the isolates except BbSA-2 and BbIDN-1, where mortality was 93.3 and 90%, respectively. The lowest mortality rate (73.3%) was recorded for BbSA-3 against 3-days-old larvae; however, all other isolates caused >80% larval mortality. Meanwhile, 93.3% mortality of 35-day-old larvae was noted for MaSA-1 isolate. The highest pupa mortality (80%) was observed for MaSA-1, while remaining isolates caused >60% mortality. The isolates BbSA-1 and MaSA-1 caused 61 and 74.3% mortality in adults, respectively. The tested fungi isolates exhibited high virulence against all life stages of red palm weevil. Local isolates had higher pathogenicity than exotic isolates. The findings of the current study suggest that entomopathogenic fungi could be used as biological control agents for the management of red palm weevil. However, field studies are needed to reach the sound conclusions and practical applications.


Assuntos
Ascomicetos/patogenicidade , Besouros/microbiologia , Controle Biológico de Vetores/métodos , Animais , Besouros/crescimento & desenvolvimento , Larva/microbiologia , Pupa/microbiologia
11.
Appl Environ Microbiol ; 87(18): e0064121, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34191531

RESUMO

The microbiome of blood-sucking arthropods can shape their competence to acquire and maintain infections with vector-borne pathogens. We used a controlled study to investigate the interactions between Borrelia afzelii, which causes Lyme borreliosis in Europe, and the bacterial microbiome of Ixodes ricinus, its primary tick vector. We applied a surface sterilization treatment to I. ricinus eggs to produce dysbiosed tick larvae that had a low bacterial abundance and a changed bacterial microbiome compared to those of the control larvae. Dysbiosed and control larvae fed on B. afzelii-infected mice and uninfected control mice, and the engorged larvae were left to molt into nymphs. The nymphs were tested for B. afzelii infection, and their bacterial microbiome underwent 16S rRNA amplicon sequencing. Surprisingly, larval dysbiosis had no effect on the vector competence of I. ricinus for B. afzelii, as the nymphal infection prevalence and the nymphal spirochete load were the same between the dysbiosed group and the control group. The strong effect of egg surface sterilization on the tick bacterial microbiome largely disappeared once the larvae molted into nymphs. The most important determinant of the bacterial microbiome of I. ricinus nymphs was the B. afzelii infection status of the mouse on which the nymphs had fed as larvae. Nymphs that had taken their larval blood meal from an infected mouse had a less abundant but more diverse bacterial microbiome than the control nymphs. Our study demonstrates that vector-borne infections in the vertebrate host shape the microbiome of the arthropod vector. IMPORTANCE Many blood-sucking arthropods transmit pathogens that cause infectious disease. For example, Ixodes ricinus ticks transmit the bacterium Borrelia afzelii, which causes Lyme disease in humans. Ticks also have a microbiome, which can influence their ability to acquire and transmit tick-borne pathogens such as B. afzelii. We sterilized I. ricinus eggs with bleach, and the tick larvae that hatched from these eggs had a dramatically reduced and changed bacterial microbiome compared to that of control larvae. These larvae fed on B. afzelii-infected mice, and the resultant nymphs were tested for B. afzelii and for their bacterial microbiome. We found that our manipulation of the bacterial microbiome had no effect on the ability of the tick larvae to acquire and maintain populations of B. afzelii. In contrast, we found that B. afzelii infection had dramatic effects on the bacterial microbiome of I. ricinus nymphs. Our study demonstrates that infections in the vertebrate host can shape the tick microbiome.


Assuntos
Grupo Borrelia Burgdorferi , Ixodes/microbiologia , Doença de Lyme/transmissão , Animais , Etanol , Feminino , Larva/microbiologia , Camundongos Endogâmicos BALB C , Microbiota , Ninfa/microbiologia , Óvulo , Hipoclorito de Sódio , Esterilização
12.
Appl Environ Microbiol ; 87(17): e0074821, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34160271

RESUMO

Several fungi, including the plant root symbiont and insect pathogen Metarhizium brunneum, produce lysergic acid amides via a branch of the ergot alkaloid pathway. Lysergic acid amides include important pharmaceuticals and pharmaceutical lead compounds and have potential ecological significance, making knowledge of their biosynthesis relevant. Many steps in the biosynthesis of lysergic acid amides have been determined, but terminal steps in the synthesis of lysergic acid α-hydroxyethylamide (LAH)-by far the most abundant lysergic acid amide in M. brunneum-are unknown. Ergot alkaloid synthesis (eas) genes are clustered in the genomes of fungi that produce these compounds, and the eas clusters of LAH producers contain two uncharacterized genes (easO and easP) not found in fungi that do not produce LAH. Knockout of easO via a CRISPR-Cas9 approach eliminated LAH and resulted in accumulation of the alternate lysergic acid amides lysergyl-alanine and ergonovine. Despite the elimination of LAH, the total concentration of lysergic acid derivatives was not affected significantly by the mutation. Complementation with a wild-type allele of easO restored the ability to synthesize LAH. Substrate feeding studies indicated that neither lysergyl-alanine nor ergonovine were substrates for the product of easO (EasO). EasO had structural similarity to Baeyer-Villiger monooxygenases (BVMOs), and labeling studies with deuterated alanine supported a role for a BVMO in LAH biosynthesis. The easO knockout had reduced virulence to larvae of the insect Galleria mellonella, indicating that LAH contributes to virulence of M. brunneum on insects and that LAH has biological activities different from ergonovine and lysergyl-alanine. IMPORTANCE Fungi in the genus Metarhizium are important plant root symbionts and insect pathogens. They are formulated commercially to protect plants from insect pests. Several Metarhizium species, including M. brunneum, were recently shown to produce ergot alkaloids, a class of specialized metabolites studied extensively in other fungi because of their importance in agriculture and medicine. A biological role for ergot alkaloids in Metarhizium species had not been demonstrated previously. Moreover, the types of ergot alkaloids produced by Metarhizium species are lysergic acid amides, which have served directly or indirectly as important pharmaceutical compounds. The terminal steps in the synthesis of the most abundant lysergic acid amide in Metarhizium species and several other fungi (LAH) have not been determined. The results of this study demonstrate the role of a previously unstudied gene in LAH synthesis and indicate that LAH contributes to virulence of M. brunneum on insects.


Assuntos
Aminas/metabolismo , Proteínas Fúngicas/metabolismo , Ácido Lisérgico/metabolismo , Metarhizium/enzimologia , Oxigenases de Função Mista/metabolismo , Animais , Vias Biossintéticas , Proteínas Fúngicas/genética , Larva/microbiologia , Metarhizium/genética , Metarhizium/metabolismo , Metarhizium/patogenicidade , Oxigenases de Função Mista/genética , Mariposas/microbiologia , Virulência
13.
FEMS Microbiol Lett ; 368(12)2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34100915

RESUMO

The first line of the Arthropods defense against infections is the hard-structured exoskeleton, a physical barrier, usually rich in insoluble chitin. For entomopathogenic fungi that actively penetrate the host body, an arsenal of hydrolytic enzymes (as chitinases and N-acetylglucosaminidases), that break down chitin, is essential. Notably, twenty-one putative chitinase genes have been identified in the genome of Metarhizium anisopliae, a generalist entomopathogenic fungus. As a multigenic family, with enzymes that, presumably, perform redundant functions, the main goal is to understand the singularity of each one of such genes and to discover their precise role in the fungal life cycle. Specially chitinases that can act as virulence determinants are of interest since these enzymes can lead to more efficient biocontrol agents. Here we explored a horizontally acquired chitinase from M. anisopliae, named chiMaD1. The deletion of this gene did not lead to phenotypic alterations or diminished supernatant's chitinolytic activity. Surprisingly, chiMaD1 deletion enhanced M. anisopliae virulence to the cattle tick (Rhipicephalus microplus) larvae and engorged females, while did not alter the virulence to the mealworm larvae (Tenebrio molitor). These results add up to recent reports of deleted genes that enhanced entomopathogenic virulence, showing the complexity of host-pathogen interactions.


Assuntos
Quitinases/genética , Proteínas Fúngicas/genética , Metarhizium/patogenicidade , Rhipicephalus/microbiologia , Animais , Quitina/metabolismo , Quitinases/metabolismo , Proteínas Fúngicas/metabolismo , Deleção de Genes , Transferência Genética Horizontal , Interações Hospedeiro-Patógeno , Larva/microbiologia , Metarhizium/classificação , Metarhizium/enzimologia , Metarhizium/genética , Controle Biológico de Vetores , Filogenia , Tenebrio/microbiologia , Virulência
14.
PLoS One ; 16(6): e0252555, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34061886

RESUMO

C. albicans is a commensal organism present in the human microbiome of more than 60% of the healthy population. Transition from commensalism to invasive candidiasis may occur after a local or a general failure of host's immune system. This transition to a more virulent phenotype may reside either on the capacity to form hyphae or on an acquired resistance to antifungal drugs. Indeed, overexpression of genes coding drug efflux pumps or adhesins, cell wall proteins facilitating the contact between the fungus and the host, usually marks the virulence profile of invasive Candida spp. In this paper, we compare virulence of two clinical isolates of C. albicans with that of laboratory-induced resistant strains by challenging G. mellonella larvae with these pathogens along with monitoring transcriptional profiles of drug efflux pumps genes CDR1, CDR2, MDR1 and the adhesin genes ALS1 and HWP1. Although both clinical isolates were found resistant to both fluconazole and micafungin they were found less virulent than laboratory-induced resistant strains. An unexpected behavior emerged for the former clinical isolate in which three genes, CDR1, CDR2 and HWP1, usually correlated with virulence, although hyperexpressed, conferred a less aggressive phenotype. On the contrary, in the other isolate, we observed a decreased expression of CDR1, CDR2 and HWP1as well as of MDR1 and ALS1 that may be consistent with the less aggressive performance observed in this strain. These altered gene expressions might directly influence Candida virulence or they might be an epiphenomenon of a vaster rearrangement occurred in these strains during the challenge with the host's environment. An in-deepth comprehension of this scenario could be crucial for developing interventions able to counteract C. albicans invasiveness and lethality.


Assuntos
Candida albicans/genética , Candida albicans/patogenicidade , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Expressão Gênica , Glicoproteínas de Membrana/genética , Proteínas de Membrana Transportadoras/genética , Animais , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/isolamento & purificação , Candidíase/microbiologia , Farmacorresistência Fúngica/efeitos dos fármacos , Farmacorresistência Fúngica/genética , Feminino , Fluconazol/farmacologia , Humanos , Hifas/genética , Larva/microbiologia , Lepidópteros/microbiologia , Micafungina/farmacologia , Testes de Sensibilidade Microbiana , Fenótipo , Virulência/genética
15.
Microbiol Res ; 250: 126802, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34174672

RESUMO

Tuta absoluta (tomato leafminer) is one of the devastating agricultural pest that attack mainly tomatoes. The continuous use of chemical pesticides is not affordable and poses a collateral damage to human and environmental health. This requires integrated pest management to reduce chemical pesticides. B. thuringiensis is a cosmopolitan, antagonistic soil bacterium used to control agricultural pests. In this study, effective Bt strains were screened from different sample sources based on their lepidopteran specific cry genes and larvicidal efficacy against tomato leafminer, T. absoluta under laboratory conditions. Of the 182 bacterial isolates, 55 (30 %) of isolates harbored parasporal protein crystals. Out of these, 34 (62 %) isolates possess one or more lepidopteran specific cry genes: 20 % of isolates positive for cry2, 18.2 % for cry9, 3.6 % for cry1, 16.4 % for cry2 + cry9, 1.8 % for cry1 + cry9, and 1.8 % for cry1 + cry2 + cry9. However, 21 (38.2 %) isolates did not show any lepidopteran specific cry genes. Isolates positive for cry genes showed 36.7-75 % and 46.7-98.3 % mortality against second and third instar larvae of the T. absoluta at the concentration of 108 colony forming units (CFUs) ml-1. Cry1 and cry1 plus other cry gene positive isolates were relatively more pathogenic against T. absoluta. However, third instar larvae of the T. absoluta was more susceptible than second instar larvae. Two of the isolates, AAUF6 and AAUMF9 were effective and scored LT50 values of 2.3 and 2.7 days and LC50 values of 3.4 × 103 and 4.15 × 103 CFUs ml-1 against the third instar larvae, respectively. The phylogenetic studies showed some congruence of groups with cry gene profiles and lethality level of isolates and very interestingly, we have detected a putative new phylogenetic group of Bt from Ethiopia.


Assuntos
Bacillus thuringiensis/genética , Bacillus thuringiensis/isolamento & purificação , Proteínas de Bactérias/genética , Lycopersicon esculentum , Mariposas/microbiologia , Filogenia , Animais , Bacillus thuringiensis/classificação , Bacillus thuringiensis/patogenicidade , Etiópia , Larva/microbiologia , Virulência
16.
mBio ; 12(3): e0050321, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34101488

RESUMO

Fungal pathogens, among other stressors, negatively impact the productivity and population size of honey bees, one of our most important pollinators (1, 2), in particular their brood (larvae and pupae) (3, 4). Understanding the factors that influence disease incidence and prevalence in brood may help us improve colony health and productivity. Here, we examined the capacity of a honey bee-associated bacterium, Bombella apis, to suppress the growth of fungal pathogens and ultimately protect bee brood from infection. Our results showed that strains of B. apis inhibit the growth of two insect fungal pathogens, Beauveria bassiana and Aspergillus flavus, in vitro. This phenotype was recapitulated in vivo; bee broods supplemented with B. apis were significantly less likely to be infected by A. flavus. Additionally, the presence of B. apis reduced sporulation of A. flavus in the few bees that were infected. Analyses of biosynthetic gene clusters across B. apis strains suggest antifungal candidates, including a type 1 polyketide, terpene, and aryl polyene. Secreted metabolites from B. apis alone were sufficient to suppress fungal growth, supporting the hypothesis that fungal inhibition is mediated by an antifungal metabolite. Together, these data suggest that B. apis can suppress fungal infections in bee brood via secretion of an antifungal metabolite. IMPORTANCE Fungi can play critical roles in host microbiomes (5-7), yet bacterial-fungal interactions are understudied. For insects, fungi are the leading cause of disease (5, 8). In particular, populations of the European honey bee (Apis mellifera), an agriculturally and economically critical species, have declined in part due to fungal pathogens. The presence and prevalence of fungal pathogens in honey bees have far-reaching consequences, endangering other species and threatening food security (1, 2, 9). Our research highlights how a bacterial symbiont protects bee brood from fungal infection. Further mechanistic work could lead to the development of new antifungal treatments.


Assuntos
Acetobacteraceae/fisiologia , Abelhas/microbiologia , Fungos/patogenicidade , Interações Microbianas , Micoses/prevenção & controle , Simbiose , Animais , Interações entre Hospedeiro e Microrganismos , Larva/microbiologia , Micoses/microbiologia
17.
mBio ; 12(3): e0027621, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34126772

RESUMO

Antibiotic-resistant Staphylococcus aureus strains constitute a major public health concern worldwide and are responsible for both health care- and community-associated infections. Here, we establish a robust and easy-to-implement model of oral S. aureus infection using Drosophila melanogaster larvae that allowed us to follow the fate of S. aureus at the whole-organism level as well as the host immune responses. Our study demonstrates that S. aureus infection triggers H2O2 production by the host via the Duox enzyme, thereby promoting antimicrobial peptide production through activation of the Toll pathway. Staphylococcal catalase mediates H2O2 neutralization, which not only promotes S. aureus survival but also minimizes the host antimicrobial response, hence reducing bacterial clearance in vivo. We show that while catalase expression is regulated in vitro by the accessory gene regulatory system (Agr) and the general stress response regulator sigma B (SigB), it no longer depends on these two master regulators in vivo. Finally, we confirm the versatility of this model by demonstrating the colonization and host stimulation capabilities of S. aureus strains belonging to different sequence types (CC8 and CC5) as well as of two other bacterial pathogens, Salmonella enterica serovar Typhimurium and Shigella flexneri. Thus, the Drosophila larva can be a general model to follow in vivo the innate host immune responses triggered during infection by human pathogens. IMPORTANCE The pathogenicity of methicillin-resistant S. aureus (MRSA) strains relies on their ability to produce a wide variety of tightly regulated virulence factors. Current in vivo models to analyze host-pathogen interactions are limited and difficult to manipulate. Here, we have established a robust and reliable model of oral S. aureus infection using Drosophila melanogaster larvae. We show that S. aureus stimulates host immunity through the production of reactive oxygen species (ROS) and antimicrobial peptide (AMP) and that ROS potentialize AMP gene expression. S. aureus catalase plays a key role in this complex environment and acts in vivo independently from SigB and Agr control. We propose that fly larvae can provide a general model for studying the colonization capabilities of human pathogens.


Assuntos
Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata , Staphylococcus aureus Resistente à Meticilina/imunologia , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Espécies Reativas de Oxigênio/imunologia , Animais , Modelos Animais de Doenças , Drosophila melanogaster/imunologia , Drosophila melanogaster/microbiologia , Regulação Bacteriana da Expressão Gênica , Larva/imunologia , Larva/microbiologia , Proteínas Citotóxicas Formadoras de Poros/genética , Proteínas Citotóxicas Formadoras de Poros/imunologia , Espécies Reativas de Oxigênio/metabolismo , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologia , Virulência
18.
mBio ; 12(3): e0040121, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34154406

RESUMO

In marine environments, the bacterially induced metamorphosis of larvae is a widespread cross-kingdom communication phenomenon that is critical for the persistence of many marine invertebrates. However, the majority of inducing bacterial signals and underlying cellular mechanisms remain enigmatic. The marine hydroid Hydractinia echinata is a well-known model system for investigating bacterially stimulated larval metamorphosis, as larvae transform into the colonial adult stage within 24 h of signal detection. Although H. echinata has served as a cell biological model system for decades, the identity and influence of bacterial signals on the morphogenic transition remained largely unexplored. Using a bioassay-guided analysis, we first determined that specific bacterial (lyso)phospholipids, naturally present in bacterial membranes and vesicles, elicit metamorphosis in Hydractinia larvae in a dose-response manner. Lysophospholipids, as single compounds or in combination (50 µM), induced metamorphosis in up to 50% of all larvae within 48 h. Using fluorescence-labeled bacterial phospholipids, we demonstrated that phospholipids are incorporated into the larval membranes, where interactions with internal signaling cascades are proposed to occur. Second, we identified two structurally distinct exopolysaccharides of bacterial biofilms, the new Rha-Man polysaccharide from Pseudoalteromonas sp. strain P1-9 and curdlan from Alcaligenes faecalis, to induce metamorphosis in up to 75% of tested larvae. We also found that combinations of (lyso)phospholipids and curdlan induced transformation within 24 h, thereby exceeding the morphogenic activity observed for single compounds and bacterial biofilms. Our results demonstrate that two structurally distinct, bacterium-derived metabolites converge to induce high transformation rates of Hydractinia larvae and thus may help ensure optimal habitat selection. IMPORTANCE Bacterial biofilms profoundly influence the recruitment and settlement of marine invertebrates, critical steps for diverse marine processes such as the formation of coral reefs, the maintenance of marine fisheries, and the fouling of submerged surfaces. However, the complex composition of biofilms often makes the characterization of individual signals and regulatory mechanisms challenging. Developing tractable model systems to characterize these coevolved interactions is the key to understanding fundamental processes in evolutionary biology. Here, we characterized two types of bacterial signaling molecules, phospholipids and polysaccharides, that induce the morphogenic transition. We then analyzed their abundance and combinatorial activity. This study highlights the general importance of multiple bacterial signal converging activity in development-related cross-kingdom signaling and poses the question of whether complex lipids and polysaccharides are general metamorphic cues for cnidarian larvae.


Assuntos
Biofilmes , Hidrozoários/microbiologia , Hidrozoários/fisiologia , Larva/microbiologia , Metamorfose Biológica , Animais , Recifes de Corais , Ecossistema
19.
Res Microbiol ; 172(4-5): 103849, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34089837

RESUMO

Co-infection with other microorganisms can promote the Candida albicans to be invasive. In this study, Escherichia coli and C. albicans were co-isolated from the women with candidiasis symptoms. The in vitro effects of E. coli on C. albicans hypha development, biofilm formation, antibiotic susceptibility, dispersion from the biofilm, expression of Als3, Hwp1, and Tup1 genes, and pathogenesis in Galleria mellonella were investigated. Electron microscopic images revealed that hypha induction was markedly increased in the bacteria-fungi co-culture. Biofilm formation was increased 2.2 fold in the presence of E. coli. The minimum inhibitory concentration of nystatin against Candida was increased from (µg mL-1) 25 to 50 in the dual biofilm. Candida dissemination was increased up to 2.7 fold from the mixed fungi/bacteria biofilm. The expression of ALS3 and HWP1 genes was increased (5.9 and 2.0 fold, respectively) while the TUP1 gene expression was decreased (0.4 fold) when C. albicans was incubated with E. coli. The simultaneous injection of C. albicans and E. coli to the insect larvae increased Galleria mortality up to 40%. This study demonstrated the effects of E. coli to promote fungi virulence factors, which suggest polymicrobial interaction should be considered during treatment of fungal infections.


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans/patogenicidade , Candidíase Vulvovaginal/microbiologia , Coinfecção/microbiologia , Escherichia coli/fisiologia , Interações Microbianas , Fatores de Virulência , Animais , Candida albicans/genética , Feminino , Humanos , Hifas/genética , Hifas/crescimento & desenvolvimento , Larva/microbiologia , Mariposas/microbiologia
20.
J Tissue Viability ; 30(3): 301-309, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34172356

RESUMO

AIM: To determine the impact of larval therapy on the debridement of venous leg ulcers, in comparison to other debridement methods or no debridement. METHOD: Using systematic review methodology, published quantitative studies focusing on the effect of larval therapy on the debridement of venous leg ulcers were included. The search was conducted in January 2020 and updated in May 2021 using CINAHL, PubMed, Embase, and the Cochrane library, and returned 357 records, of which six studies met the inclusion criteria. Data were extracted using a predesigned extraction tool and all studies were quality appraised using the RevMan risk of bias assessment tool. RESULTS: Larval therapy was found to debride at a faster rate than hydrogel (p = 0.011, p < 0.001, p = 0.0039), have a similar effect to sharp debridement (p = 0.12, p = 0.62), and was a resource-effective method of debridement (p < 0.05, p < 0.001, p < 0.001). When larval therapy in combination with compression therapy was compared to compression alone, larvae had a greater effect on debridement (p < 0.05), however, it did not improve overall wound healing rates (p = 0.54, p = 0.664, p = 0.02). Pain levels increased during larval therapy and reduced after treatment, when compared to other standard debridement techniques. CONCLUSION: Larval therapy promotes rapid debridement of venous leg ulcers. However, further high quality randomised controlled trials, comparing larval therapy to other debridement methods for venous leg ulcers, incorporating the use of compression is required to determine the long term effects of larval therapy.


Assuntos
Desbridamento/métodos , Larva/metabolismo , Perna (Membro)/anormalidades , Úlcera Varicosa/terapia , Animais , Humanos , Larva/microbiologia , Perna (Membro)/fisiopatologia , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Úlcera Varicosa/fisiopatologia
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