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1.
Mar Drugs ; 22(2)2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38393061

RESUMO

Protein hydrolysates from sea cucumber (Apostichopus japonicus) gonads are rich in active materials with remarkable angiotensin-converting enzyme (ACE) inhibitory activity. Alcalase was used to hydrolyze sea cucumber gonads, and the hydrolysate was separated by the ultrafiltration membrane to produce a low-molecular-weight peptide component (less than 3 kDa) with good ACE inhibitory activity. The peptide component (less than 3 kDa) was isolated and purified using a combination method of ACE gel affinity chromatography and reverse high-performance liquid chromatography. The purified fractions were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the resulting products were filtered using structure-based virtual screening (SBVS) to obtain 20 peptides. Of those, three noncompetitive inhibitory peptides (DDQIHIF with an IC50 value of 333.5 µmol·L-1, HDWWKER with an IC50 value of 583.6 µmol·L-1, and THDWWKER with an IC50 value of 1291.8 µmol·L-1) were further investigated based on their favorable pharmacochemical properties and ACE inhibitory activity. Molecular docking studies indicated that the three peptides were entirely enclosed within the ACE protein cavity, improving the overall stability of the complex through interaction forces with the ACE active site. The total free binding energies (ΔGtotal) for DDQIHIF, HDWWKER, and THDWWKER were -21.9 Kcal·mol-1, -71.6 Kcal·mol-1, and -69.1 Kcal·mol-1, respectively. Furthermore, a short-term assay of antihypertensive activity in spontaneously hypertensive rats (SHRs) revealed that HDWWKER could significantly decrease the systolic blood pressure (SBP) of SHRs after intravenous administration. The results showed that based on the better antihypertensive activity of the peptide in SHRs, the feasibility of targeted affinity purification and computer-aided drug discovery (CADD) for the efficient screening and preparation of ACE inhibitory peptide was verified, which provided a new idea of modern drug development method for clinical use.


Assuntos
Anti-Hipertensivos , Pepinos-do-Mar , Ratos , Animais , Anti-Hipertensivos/farmacologia , Inibidores da Enzima Conversora de Angiotensina/química , Cromatografia Líquida , Simulação de Acoplamento Molecular , Pepinos-do-Mar/metabolismo , Espectrometria de Massas em Tandem , Peptídeos/química , Ratos Endogâmicos SHR , Cromatografia de Afinidade , Peptidil Dipeptidase A/química , Hidrolisados de Proteína/química , Gônadas/metabolismo , Angiotensinas
2.
Medicine (Baltimore) ; 103(5): e37161, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38306539

RESUMO

RATIONALE: Comamonas kerstersii mainly causes intra-abdominal infections with favorable outcomes due to high antibiotic susceptibility. We report the first case of pneumonia caused by C Kerstersii, which promoted patient death, and a second urinary tract infection by C Kerstersii with extensive drug resistance. PATIENT CONCERNS: A 46-year-old male (Case 1) with craniocerebral injury underwent emergency decompressive craniectomy, but his condition deteriorated further and presented with discontinuous fever, small moist rales on both lungs, and respiratory failure. Retrospective average nucleotide identity (ANI) analysis of the genomic sequence of the sputum isolate identified it as C Kerstersii 12322-1, antimicrobial susceptibility testing (AST) revealed that it was sensitive to 18 of 21 tested antibiotics.An 82-year-old male (Case 2) with hypertrophic prostate experienced gradual obstruction during urination, and a urine test revealed WBC ++. Retrospective ANI analysis of the urine isolate identified it as C Kerstersii 121606, which was resistant to 18 of 21 tested antibiotics. DIAGNOSES: Case 1 was diagnosed empirically as pneumonia caused by C Kerstersii strain 12322-1 secondary to craniocerebral injury and confirmed by retrospective ANI analysis; case 2 was diagnosed empirically as urinary infection secondary to prostate hyperplasia caused by C Kerstersii strain 121606 confirmed by the retrospective ANI analysis. INTERVENTIONS: Case 1 was administered cefoxitin, cefodizime, imipenem-cilastatin sodium, and underwent comprehensive salvage management. Case 2 was administered doxycycline alone. OUTCOMES: Case 1 died partially because of untimely identification of the responsible bacteria-12322-1. Case 2 was cured even 121606 exhibited an extensive drug resistance feature. LESSONS: Except for intra-abdominal infections with good prognosis, we verified that C Kerstersii could also cause extra-abdominal infections, such as the first pneumonia case and urinary infection. It could promote patient death; actual infections were underestimated due to identification difficulties, posing a health threat due to the presence of extensive drug resistance.


Assuntos
Comamonas , Traumatismos Craniocerebrais , Infecções Intra-Abdominais , Pneumonia , Infecções Urinárias , Masculino , Humanos , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Estudos Retrospectivos , Infecções Intra-Abdominais/diagnóstico , Infecções Intra-Abdominais/tratamento farmacológico , Antibacterianos/uso terapêutico , Infecções Urinárias/tratamento farmacológico
3.
J Med Chem ; 67(1): 138-151, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38153295

RESUMO

Androgen receptor (AR) is the primary target for treating prostate cancer (PCa), which inevitably progresses due to drug-resistant mutations. Bromodomain-containing protein 4 (BRD4) has been a new potential drug target for PCa treatment. Herein, we report the rational design and discovery of novel BRD4 inhibitors through computer-aided drug design (CADD), and a hit compound SQ-1 (IC50 = 676 nM) was identified by structure-based virtual screening (SBVS) with the conserved water network. To optimize the structure of SQ-1, the free energy landscape was constructed, and the binding mechanism was explored by characterizing the water profile and the dissociation mechanism. Finally, the compound SQ-17 with improved inhibitory activity (IC50 < 100 nM) was discovered, which showed potent antiproliferative activity against LNCaP. These data highlighted a successful attempt to identify and optimize a small molecule by comprehensive CADD application and provided essential clues for developing novel therapeutics for PCa treatment.


Assuntos
Antineoplásicos , Neoplasias da Próstata , Masculino , Humanos , Fatores de Transcrição , Proteínas Nucleares , Água/química , Detecção Precoce de Câncer , Desenho de Fármacos , Proteínas de Ciclo Celular/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Relação Estrutura-Atividade , Antineoplásicos/química , Proteínas que Contêm Bromodomínio
4.
Microbiol Resour Announc ; 12(12): e0048823, 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-37921484

RESUMO

The draft genome of Flavobacterium tructae strain S12, isolated from hatchery-reared Chinook salmon (Oncorhynchus tshawytscha) fingerlings, consisted of 5,695,942 bp, a G + C content of 35.6%, 4,775 predicted open reading frames, a putative type IX secretion system, collagenase, and hemolysin. F. tructae strains can be used as models for emerging Flavobacterium pathogens.

5.
Mar Drugs ; 21(10)2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37888457

RESUMO

An affinity chromatography filler of CNBr-activated Sepharose 4B-immobilized ACE was used to purify ACE-inhibitory peptides from Takifugu flavidus protein hydrolysate (<1 kDa). Twenty-four peptides with an average local confidence score (ALC) ≥ 80% from bounded components (eluted by 1 M NaCl) were identified by LC-MS/MS. Among them, a novel peptide, TLRFALHGME, with ACE-inhibitory activity (IC50 = 93.5 µmol·L-1) was selected. Molecular docking revealed that TLRFALHGME may interact with the active site of ACE through H-bond, hydrophobic, and electrostatic interactions. The total binding energy (ΔGbinding) of TLRFALHGME was estimated to be -82.7382 kJ·mol-1 by MD simulations, indicating the favorable binding of peptides with ACE. Furthermore, the binding affinity of TLRFALHGME to ACE was determined by surface plasmon resonance (SPR) with a Kd of 80.9 µmol, indicating that there was a direct molecular interaction between them. TLRFALHGME has great potential for the treatment of hypertension.


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Takifugu , Animais , Inibidores da Enzima Conversora de Angiotensina/química , Takifugu/metabolismo , Cromatografia Líquida , Simulação de Acoplamento Molecular , Espectrometria de Massas em Tandem , Peptídeos/farmacologia , Cromatografia de Afinidade/métodos , Peptidil Dipeptidase A/química , Hidrolisados de Proteína/química , Angiotensinas
6.
Front Cell Infect Microbiol ; 13: 1223090, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37743862

RESUMO

Background: Bovine respiratory disease (BRD) is the most devastating disease affecting beef and dairy cattle producers in North America. An emerging area of interest is the respiratory microbiome's relationship with BRD. However, results regarding the effect of BRD on respiratory microbiome diversity are conflicting. Results: To examine the effect of BRD on the alpha diversity of the respiratory microbiome, a meta-analysis analyzing the relationship between the standardized mean difference (SMD) of three alpha diversity metrics (Shannon's Diversity Index (Shannon), Chao1, and Observed features (OTUs, ASVs, species, and reads) and BRD was conducted. Our multi-level model found no difference in Chao1 and Observed features SMDs between calves with BRD and controls. The Shannon SMD was significantly greater in controls compared to that in calves with BRD. Furthermore, we re-analyzed 16S amplicon sequencing data from four previously published datasets to investigate BRD's effect on individual taxa abundances. Additionally, based on Bray Curtis and Jaccard distances, health status, sampling location, and dataset were all significant sources of variation. Using a consensus approach based on RandomForest, DESeq2, and ANCOM-BC2, we identified three differentially abundant amplicon sequence variants (ASVs) within the nasal cavity, ASV5_Mycoplasma, ASV19_Corynebacterium, and ASV37_Ruminococcaceae. However, no ASVs were differentially abundant in the other sampling locations. Moreover, based on SECOM analysis, ASV37_Ruminococcaceae had a negative relationship with ASV1_Mycoplasma_hyorhinis, ASV5_Mycoplasma, and ASV4_Mannheimia. ASV19_Corynebacterium had negative relationships with ASV1_Mycoplasma_hyorhinis, ASV4_Mannheimia, ASV54_Mycoplasma, ASV7_Mycoplasma, and ASV8_Pasteurella. Conclusions: Our results confirm a relationship between bovine respiratory disease and respiratory microbiome diversity and composition, which provide additional insight into microbial community dynamics during BRD development. Furthermore, as sampling location and sample processing (dataset) can also affect results, consideration should be taken when comparing results across studies.


Assuntos
Doenças dos Bovinos , Microbiota , Mycoplasma hyorhinis , Doenças Respiratórias , Bovinos , Animais , Clostridiales
7.
J Anim Ecol ; 92(11): 2189-2200, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37766488

RESUMO

In cooperatively breeding birds, why do some individuals breed independently but others have to help at home? This question has been rarely addressed despite its fundamental importance for understanding the evolution of social cooperation. We address it using 15 years of data from Tibetan ground tits Pseudopodoces humilis where helpers consist of younger males. Since whether younger males successfully breed depends critically on their chances to occupy territories nearby home, our analytic strategy is to identify the determinants of individual differences in gaining territory ownership among these ready-to-breed males. Across widowed, last-year helper and yearling males, an age advantage was evident in inheriting resident territories, occupying adjacent vacancies and budding off part of adjacent territories, which left some last-year helpers and most yearling males to take the latter two routes. These males were more likely to acquire a territory if they were genetically related to the previous or current territory owners; otherwise they remained on natal territories as helpers. The relatedness effect can arise from the prior residence advantage established in the preceding winter when younger males followed their parents to perform kin-directed off-territory forays. Our research highlights the key role of local kinship in determining younger males' territory acquisition and thus their fate in terms of independent reproduction versus help. This finding provides insight into the formation of kin-based, facultative cooperative societies prevailing among vertebrates.


Assuntos
Núcleo Familiar , Passeriformes , Humanos , Masculino , Animais , Comportamento Social , Passeriformes/genética , Cruzamento , Reprodução , Comportamento Cooperativo
8.
Brief Bioinform ; 25(1)2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-38171930

RESUMO

Protein loops play a critical role in the dynamics of proteins and are essential for numerous biological functions, and various computational approaches to loop modeling have been proposed over the past decades. However, a comprehensive understanding of the strengths and weaknesses of each method is lacking. In this work, we constructed two high-quality datasets (i.e. the General dataset and the CASP dataset) and systematically evaluated the accuracy and efficiency of 13 commonly used loop modeling approaches from the perspective of loop lengths, protein classes and residue types. The results indicate that the knowledge-based method FREAD generally outperforms the other tested programs in most cases, but encountered challenges when predicting loops longer than 15 and 30 residues on the CASP and General datasets, respectively. The ab initio method Rosetta NGK demonstrated exceptional modeling accuracy for short loops with four to eight residues and achieved the highest success rate on the CASP dataset. The well-known AlphaFold2 and RoseTTAFold require more resources for better performance, but they exhibit promise for predicting loops longer than 16 and 30 residues in the CASP and General datasets. These observations can provide valuable insights for selecting suitable methods for specific loop modeling tasks and contribute to future advancements in the field.


Assuntos
Proteínas , Conformação Proteica , Proteínas/química
9.
Nat Comput Sci ; 3(9): 789-804, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38177786

RESUMO

Ligand docking is one of the core technologies in structure-based virtual screening for drug discovery. However, conventional docking tools and existing deep learning tools may suffer from limited performance in terms of speed, pose quality and binding affinity accuracy. Here we propose KarmaDock, a deep learning approach for ligand docking that integrates the functions of docking acceleration, binding pose generation and correction, and binding strength estimation. The three-stage model consists of the following components: (1) encoders for the protein and ligand to learn the representations of intramolecular interactions; (2) E(n) equivariant graph neural networks with self-attention to update the ligand pose based on both protein-ligand and intramolecular interactions, followed by post-processing to ensure chemically plausible structures; (3) a mixture density network for scoring the binding strength. KarmaDock was validated on four benchmark datasets and tested in a real-world virtual screening project that successfully identified experiment-validated active inhibitors of leukocyte tyrosine kinase (LTK).


Assuntos
Redes Neurais de Computação , Proteínas , Ligação Proteica , Ligantes , Simulação de Acoplamento Molecular , Proteínas/química
10.
Int J Mol Sci ; 23(23)2022 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-36499176

RESUMO

Candidate peptides with novel angiotensin-I-converting enzyme (ACE) inhibitor activity were obtained from hydrolysates of Gracilariopsis lemaneiformis by virtual screening method. Our results showed that G. lemaneiformis peptides (GLP) could significantly lower blood pressure in spontaneously hypertensive rats (SHR). At least 101 peptide sequences of GLP were identified by LC-MS/MS analysis and subjected to virtual screening. A total of 20 peptides with the highest docking score were selected and chemically synthesized in order to verify their ACE-inhibitory activities. Among them, SFYYGK, RLVPVPY, and YIGNNPAKG showed good effects with IC50 values of 6.45 ± 0.22, 9.18 ± 0.42, and 11.23 ± 0.23 µmoL/L, respectively. Molecular docking studies revealed that three peptides interacted with the active center of ACE by hydrogen bonding, hydrophobic interactions, and electrostatic forces. These peptides could form stable complexes with ACE. Furthermore, SFYYGK, RLVPVPY, and YIGNNPAKG significantly reduced systolic blood pressure (SBP) in SHR. YIGNNPAKG exhibited the highest antihypertensive effect, with the largest decrease in SBP (approximately 23 mmHg). In conclusion, SFYYGK, RLVPVPY, and YIGNNPAKG can function as potent therapeutic candidates for hypertension treatment.


Assuntos
Hipertensão , Rodófitas , Ratos , Animais , Hipertensão/tratamento farmacológico , Simulação de Acoplamento Molecular , Cromatografia Líquida , Peptidil Dipeptidase A/química , Espectrometria de Massas em Tandem , Anti-Hipertensivos/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Ratos Endogâmicos SHR , Peptídeos/química , Hidrolisados de Proteína/química
11.
Medicine (Baltimore) ; 101(45): e31399, 2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36397445

RESUMO

Our study aimed to develop a prediction model to predict the short-term mortality of hepatocellular carcinoma (HCC) patients with lung metastasis. The retrospective data of HCC patients with lung metastasis was from the Surveillance, Epidemiology, and End Results registration database between 2010 and 2015. 1905 patients were randomly divided into training set (n = 1333) and validation set (n = 572). There were 1092 patients extracted from the Surveillance, Epidemiology, and End Results database 2015 to 2019 as the validation set. The variable importance was calculated to screen predictors. The constructed prediction models of logistic regression, random forest, broad learning system, deep neural network, support vector machine, and naïve Bayes were compared through the predictive performance. The mortality of HCC patients with lung metastasis was 51.65% within 1 month. The screened prognostic factors (age, N stage, T stage, tumor size, surgery, grade, radiation, and chemotherapy) and gender were used to construct prediction models. The area under curve (0.853 vs. 0.771) of random forest model was more optimized than that of logistic regression model in the training set. But, there were no significant differences in testing and validation sets between random forest and logistic regression models. The value of area under curve in the logistic regression model was significantly higher than that of the broad learning system model (0.763 vs. 0.745), support vector machine model (0.763 vs. 0.689) in the validation set, and higher than that of the naïve Bayes model (0.775 vs. 0.744) in the testing model. We further chose the logistic regression prediction model and built the prognostic nomogram. We have developed a prediction model for predicting short-term mortality with 9 easily acquired predictors of HCC patients with lung metastasis, which performed well in the internal and external validation. It could assist clinicians to adjust treatment strategies in time to improve the prognosis.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Neoplasias Pulmonares , Humanos , Carcinoma Hepatocelular/terapia , Carcinoma Hepatocelular/secundário , Estudos Retrospectivos , Neoplasias Hepáticas/terapia , Neoplasias Hepáticas/patologia , Teorema de Bayes , Prognóstico
13.
Indian J Microbiol ; 62(2): 280-292, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35462713

RESUMO

Microbial pigments have been widely applied to printing in food, textile, and paper industries as a sustainable alternative to synthetic dyes. Herein, we isolated a novel Talaromyces aurantiacus strain with a strong ability to produce red pigments. We further studied pigment production conditions, stability, screen printing application, and bioactivities. Our results showed that sucrose was a favourable carbon source and the addition of l-histidine significantly enhanced the production of red pigments. Pigment production was strictly photo-regulated with effective wavelengths around 450 nm (blue light). We mixed the red pigments with cellulosic materials and explored their application potentials for screen printing on paper, cotton fabrics, and polymeric carriers. The printing density was significantly improved from 0.3 to 0.7 by overlay printing. T. aurantiacus pigments could be stably stored at pH 5-11, temperature - 10 to 70 °C, and redox potential - 200 to 300 mV. Moreover, the stable ranges were extended to pH 1-11 and temperature over 100 °C after screen-printed on paper. The red pigments exhibited antioxidant activity towards 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (IC50 10.4 mg L-1 in solution). Our results further indicated the red pigments by T. aurantiacus was environmentally friendly based on acetylcholinesterase activity assay. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01008-x.

14.
Mar Drugs ; 19(12)2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34940650

RESUMO

Alcalase, neutral protease, and pepsin were used to hydrolyze the skin of Takifugu flavidus. The T. flavidus hydrolysates (TFHs) with the maximum degree of hydrolysis (DH) and angiotensin-I-converting enzyme (ACE)-inhibitory activity were selected and then ultra-filtered to obtain fractions with components of different molecular weights (MWs) (<1, 1-3, 3-10, 10-50, and >50 kDa). The components with MWs < 1 kDa showed the strongest ACE-inhibitory activity with a half-maximal inhibitory concentration (IC50) of 0.58 mg/mL. Purification and identification using semi-preparative liquid chromatography, Sephadex G-15 gel chromatography, RP-HPLC, and LC-MS/MS yielded one new potential ACE-inhibitory peptide, PPLLFAAL (non-competitive suppression mode; IC50 of 28 µmmol·L-1). Molecular docking and molecular dynamics simulations indicated that the peptides should bind well to ACE and interact with amino acid residues and the zinc ion at the ACE active site. Furthermore, a short-term assay of antihypertensive activity in spontaneously hypertensive rats (SHRs) revealed that PPLLFAAL could significantly decrease the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of SHRs after intravenous administration. These results suggested that PPLLFAAL may have potential applications in functional foods or pharmaceuticals as an antihypertensive agent.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Peptídeos/farmacologia , Peptidil Dipeptidase A/efeitos dos fármacos , Takifugu , Inibidores da Enzima Conversora de Angiotensina/química , Animais , Organismos Aquáticos , Pressão Sanguínea/efeitos dos fármacos , Modelos Animais de Doenças , Hipertensão , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Peptídeos/química , Peptidil Dipeptidase A/química , Ratos , Ratos Endogâmicos SHR , Pele/química
15.
Genes (Basel) ; 12(5)2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34067621

RESUMO

Asaia bacteria commonly comprise part of the microbiome of many mosquito species in the genera Anopheles and Aedes, including important vectors of infectious agents. Their close association with multiple organs and tissues of their mosquito hosts enhances the potential for paratransgenesis for the delivery of antimalaria or antivirus effectors. The molecular mechanisms involved in the interactions between Asaia and mosquito hosts, as well as Asaia and other bacterial members of the mosquito microbiome, remain underexplored. Here, we determined the genome sequence of Asaia strain W12 isolated from Anopheles stephensi mosquitoes, compared it to other Asaia species associated with plants or insects, and investigated the properties of the bacteria relevant to their symbiosis with mosquitoes. The assembled genome of strain W12 had a size of 3.94 MB, the largest among Asaia spp. studied so far. At least 3585 coding sequences were predicted. Insect-associated Asaia carried more glycoside hydrolase (GH)-encoding genes than those isolated from plants, showing their high plant biomass-degrading capacity in the insect gut. W12 had the most predicted regulatory protein components comparatively among the selected Asaia, indicating its capacity to adapt to frequent environmental changes in the mosquito gut. Two complete operons encoding cytochrome bo3-type ubiquinol terminal oxidases (cyoABCD-1 and cyoABCD-2) were found in most Asaia genomes, possibly offering alternative terminal oxidases and allowing the flexible transition of respiratory pathways. Genes involved in the production of 2,3-butandiol and inositol have been found in Asaia sp. W12, possibly contributing to biofilm formation and stress tolerance.


Assuntos
Acetobacteraceae/genética , Anopheles/microbiologia , Genoma Bacteriano , Simbiose , Acetobacteraceae/patogenicidade , Animais , Proteínas de Bactérias/genética , Glicosídeo Hidrolases/genética , Inositol/biossíntese , Intestinos/microbiologia , Fases de Leitura Aberta , Óperon
16.
Int J Mol Sci ; 22(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672911

RESUMO

The Gram-negative bacterium Flavobacterium johnsoniae employs gliding motility to move rapidly over solid surfaces. Gliding involves the movement of the adhesin SprB along the cell surface. F. johnsoniae spreads on nutrient-poor 1% agar-PY2, forming a thin film-like colony. We used electron microscopy and time-lapse fluorescence microscopy to investigate the structure of colonies formed by wild-type (WT) F. johnsoniae and by the sprB mutant (ΔsprB). In both cases, the bacteria were buried in the extracellular polymeric matrix (EPM) covering the top of the colony. In the spreading WT colonies, the EPM included a thick fiber framework and vesicles, revealing the formation of a biofilm, which is probably required for the spreading movement. Specific paths that were followed by bacterial clusters were observed at the leading edge of colonies, and abundant vesicle secretion and subsequent matrix formation were suggested. EPM-free channels were formed in upward biofilm protrusions, probably for cell migration. In the nonspreading ΔsprB colonies, cells were tightly packed in layers and the intercellular space was occupied by less matrix, indicating immature biofilm. This result suggests that SprB is not necessary for biofilm formation. We conclude that F. johnsoniae cells use gliding motility to spread and maturate biofilms.


Assuntos
Adesinas Bacterianas/metabolismo , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Flavobacterium/fisiologia , Locomoção/fisiologia , Proteínas de Bactérias/genética , Flavobacterium/genética , Flavobacterium/ultraestrutura , Locomoção/genética , Microscopia Eletrônica de Transmissão/métodos , Microscopia de Fluorescência/métodos , Mutação , Imagem com Lapso de Tempo/métodos
17.
Front Microbiol ; 12: 754593, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35002999

RESUMO

Effective pretreatment is vital to improve the biomass conversion efficiency, which often requires the addition of xylanase as an accessory enzyme to enhance enzymatic saccharification of corn stover. In this study, we investigated the effect of two sophisticated pretreatment methods including ammonium sulfite (AS) and steam explosion (SE) on the xylanase profits involved in enzymatic hydrolysis of corn stover. We further explored the interactions between lignin and xylanase Xyn10A protein. Our results showed that the conversion rates of glucan and xylan in corn stover by AS pretreatment were higher by Xyn10A supplementation than that by SE pretreatment. Compared with the lignin from SE pretreated corn stover, the lignin from AS pretreated corn stover had a lower Xyn10A initial adsorption velocity (13.56 vs. 10.89 mg g-1 min-1) and adsorption capacity (49.46 vs. 27.42 mg g-1 of lignin) and weakened binding strength (310.6 vs. 215.9 L g-1). Our study demonstrated the low absolute zeta potential and strong hydrophilicity of the lignin may partly account for relative weak interaction between xylanase protein and lignin from AS pretreated corn stover. In conclusion, our results suggested that AS pretreatment weakened the inhibition of lignin to enzyme, promoted the enzymatic hydrolysis of corn stover, and decreased the cost of enzyme in bioconversion.

18.
Sci Rep ; 10(1): 18068, 2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-33093485

RESUMO

The citrus fruit fly Bactrocera (Tetradacus) minax is a major and devastating agricultural pest in Asian subtropical countries. Previous studies have shown that B. minax interacts with plant hosts via the efficient chemosensory system. However, the molecular components of the B. minax chemosensory system have not been well characterized. Herein, we identified a total of 25 putative odorant-binding receptors (OBPs), 4 single-copy chemosensory proteins (CSPs) and 53 candidate odorant receptors (ORs) using a newly generated whole-genome dataset for B. minax. This study significantly extended the chemosensation-related gene profiles (particularly, OBPs and ORs) in six other tephritid species. Comparative transcriptome analysis of adult B. minax and Bactrocera dorsalis showed that there were 14 highly expressed OBPs (FPKM > 100) in B. dorsalis and 7 highly expressed ones in B. minax. The expression level of CSP3 gene and CSP4 gene was higher in B. dorsalis than that in B. minax. Comparative genomic and transcriptomic analyses of chemosensory genes in the citrus fruit fly B. minax provided new insights for preventive control of this agriculture important pest and closely related species.


Assuntos
Genômica/métodos , Proteínas de Insetos/genética , Receptores Odorantes/genética , Tephritidae/genética , Transcriptoma , Animais , Citrus , Perfilação da Expressão Gênica , Filogenia
19.
Front Microbiol ; 11: 804, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32457715

RESUMO

In this study, we investigated the global gene expression responses of Elizabethkingia anophelis to iron fluxes in the midgut of female Anopheles stephensi mosquitoes fed sucrose or blood, and in iron-poor or iron-rich culture conditions. Of 3,686 transcripts revealed by RNAseq technology, 218 were upregulated while 112 were down-regulated under iron-poor conditions. Hemolysin gene expression was significantly repressed when cells were grown under iron-rich or high temperature (37°C) conditions. Furthermore, hemolysin gene expression was down-regulated after a blood meal, indicating that E. anophelis cells responded to excess iron and its associated physiological stress by limiting iron loading. By contrast, genes encoding respiratory chain proteins were up-regulated under iron-rich conditions, allowing these iron-containing proteins to chelate intracellular free iron. In vivo studies showed that growth of E. anophelis cells increased 3-fold in blood-fed mosquitoes over those in sucrose-fed ones. Deletion of siderophore synthesis genes led to impaired cell growth in both iron-rich and iron-poor media. Mutants showed more susceptibility to H2O2 toxicity and less biofilm formation than did wild-type cells. Mosquitoes with E. anophelis experimentally colonized in their guts produced more eggs than did those treated with erythromycin or left unmanipulated, as controls. Results reveal that E. anophelis bacteria respond to varying iron concentration in the mosquito gut, harvest iron while fending off iron-associated stress, contribute to lysis of red blood cells, and positively influence mosquito host fecundity.

20.
Microbiol Resour Announc ; 9(17)2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32327519

RESUMO

The bacterium Serratia fonticola strain S14, isolated from the midgut of a female Aedes triseriatus mosquito, has a genome size of 6,176,978 bp. The genome includes genes responsible for acyl-homoserine lactone-mediated quorum sensing, enterobactin, and aerobactin.

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