Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Appl Microbiol Biotechnol ; 104(4): 1609-1619, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31900556

RESUMO

The emergence of antibiotic-resistant beta-hemolytic Streptococcus agalactiae strains poses increasing threat to human beings globally. As an attempt to create a novel lysin with improved activity against S. agalactiae, a chimeric lysin, ClyV, was constructed by fusing the enzymatically active domain (EAD) from PlyGBS lysin (GBS180) and the cell wall binding domain (CBD) from PlyV12 lysin (V12CBD). Plate lysis assay combined with lytic kinetic analysis demonstrated that ClyV has improved activity than its parental enzymatic domain GBS180 against multiple streptococci. Biochemical characterization showed that ClyV is active from pH 7 to 10, with the optimum pH of 9, and is stable under NaCl concentration of < 500 mM. In a S. agalactiae infection model, a single intraperitoneally administration of 0.1 mg/mouse of ClyV protected 100% mice, while it was observed that ~ 29% survive in group that received a single dose of 0.1 mg/mouse of GBS180. Moreover, a high dose of 0.8 mg/mouse ClyV did not show any adverse effects to the health or survival rate of the mice. Considering the robust bactericidal activity and good safety profile of ClyV, it represents a potential candidate for the treatment of S. agalactiae infections.

2.
Antimicrob Agents Chemother ; 64(2)2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31767724

RESUMO

Streptococcus pneumoniae is a leading human pathogen uniquely characterized by choline moieties on the bacterial surface. Our previous work reported a pneumococcus-specific chimeric lysin, ClyJ, which combines the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) enzymatically active domain (EAD) from the PlyC lysin and the cell wall binding domain (CBD) from the phage SPSL1 lysin, which imparts choline binding specificity. Here, we demonstrate that the lytic activity of ClyJ can be further improved by editing the linker sequence adjoining the EAD and CBD. Keeping the net charge of the linker constant, we constructed three ClyJ variants containing different lengths of linker sequence. Circular dichroism showed that linker editing has only minor effects on the folding of the EAD and CBD. However, thermodynamic examination combined with biochemical analysis demonstrated that one variant, ClyJ-3, with the shortest linker, displayed improved thermal stability and bactericidal activity, as well as reduced cytotoxicity. In a pneumococcal mouse infection model, ClyJ-3 showed significant protective efficacy compared to that of the ClyJ parental lysin or the Cpl-1 lysin, with 100% survival at a single ClyJ-3 intraperitoneal dose of 100 µg/mouse. Moreover, a ClyJ-3 dose of 2 µg/mouse had the same efficacy as a ClyJ dose of 40 µg/mouse, suggesting a 20-fold improvement in vivo Taking these results together, the present study not only describes a promising pneumococcal lysin with improved potency, i.e., ClyJ-3, but also implies for the first time that the linker sequence plays an important role in determining the activity of a chimeric lysin, providing insight for future lysin engineering studies.

3.
Environ Microbiol ; 22(3): 1125-1140, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31858668

RESUMO

Bacillus thuringiensis is the most widely used eco-friendly biopesticide, containing two primary determinants of biocontrol, endospore and insecticidal crystal proteins (ICPs). The 2-methylcitrate cycle is a widespread carbon metabolic pathway playing a crucial role in channelling propionyl-CoA, but with poorly understood metabolic regulatory mechanisms. Here, we dissect the transcriptional regulation of the 2-methylcitrate cycle operon prpCDB and report its unprecedented role in controlling the sporulation process of B. thuringiensis. We found that the transcriptional activity of the prp operon encoding the three critical enzymes PrpC, PrpD, and PrpB in the 2-methylcitrate cycle was negatively regulated by the two global transcription factors CcpA and AbrB, while positively regulated by the LysR family regulator CcpC, which jointly account for the fact that the 2-methylcitrate cycle is specifically and highly active in the stationary phase of growth. We also found that the prpD mutant accumulated 2-methylcitrate, the intermediate metabolite of the 2-methylcitrate cycle, which delayed and inhibited sporulation at the early stage. Thus, our results not only revealed sophisticated transcriptional regulatory mechanisms for the metabolic 2-methylcitrate cycle but also identified 2-methylcitrate as a novel regulator of sporulation in B. thuringiensis.

4.
Front Psychol ; 10: 1888, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507480

RESUMO

Purpose: The primary aim of the present study is to examine the effect of 8-week mind-body exercise intervention combining aerobic jogging and mindfulness-based yoga on implicit emotion regulation ability. The secondary aim is to explore the specific potential pathways by which the mind-body exercise intervention fosters implicit emotion regulation. This may help us to understand how the key components of exercise intervention contribute to emotional benefits. Methods: Sixty participants were randomly allocated to one of two parallel groups: (1) the intervention group (n = 29) and (2) the waitlist control group (n = 31). Participants were asked to fill out scales measuring mindfulness and instructed to complete an emotion regulation task to assess implicit emotion regulation ability as well as the PWC 170 Test to evaluate aerobic fitness before and after the intervention. Results: The results of the two-way repeated ANOVA revealed that 8 weeks of intervention improved implicit emotion regulation, mindfulness, and aerobic fitness levels. Path analysis showed that only improved aerobic fitness mediated the intervention effect on implicit emotion regulation ability, controlling for change in negative affect. Notably, the relationship between the effects on implicit emotion regulation ability and aerobic fitness was moderated by improved mindfulness. Conclusion: Eight weeks of mind-body exercise intervention improves implicit emotion regulation ability. The aerobic fitness may be an essential pathway which mediates the efficacy on implicit emotion regulation ability. Furthermore, different components, such as aerobic fitness and mindfulness, may interactively contribute to such emotional benefits.

5.
Artigo em Inglês | MEDLINE | ID: mdl-30642930

RESUMO

Streptococcus pneumoniae is one of the leading pathogens that cause a variety of mucosal and invasive infections. With the increased emergence of multidrug-resistant S. pneumoniae, new antimicrobials with mechanisms of action different from conventional antibiotics are urgently needed. In this study, we identified a putative lysin (gp20) encoded by the Streptococcus phage SPSL1 using the LytA autolysin as a template. Molecular dissection of gp20 revealed a binding domain (GPB) containing choline-binding repeats (CBRs) that are high specificity for S. pneumoniae By fusing GPB to the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) catalytic domain of the PlyC lysin, we constructed a novel chimeric lysin, ClyJ, with improved activity to the pneumococcal Cpl-1 lysin. No resistance was observed in S. pneumoniae strains after exposure to incrementally doubling concentrations of ClyJ for 8 continuous days in vitro In a mouse bacteremia model using penicillin G as a control, a single intraperitoneal injection of ClyJ improved the survival rate of lethal S. pneumoniae-infected mice in a dose-dependent manner. Given its high lytic activity and safety profile, ClyJ may represent a promising alternative to combat pneumococcal infections.

6.
Artigo em Inglês | MEDLINE | ID: mdl-30397070

RESUMO

The determination of antibiotic potency against bacterial strains by assessment of their minimum inhibitory concentration normally uses a standardized broth microdilution assay procedure developed more than 50 years ago. However, certain antibiotics require modified assay conditions in order to observe optimal activity. For example, daptomycin requires medium supplemented with Ca2+, and the lipoglycopeptides dalbavancin and oritavancin require Tween 80 to be added to the growth medium to prevent the depletion of free drug via adsorption to the plastic microplate. In this report, we examine systematically the effects of several different plate types on microdilution broth MIC values for a set of antibiotics against Gram-positive and Gram-negative bacteria, both in medium alone and in medium supplemented with the commonly used additives Tween 80, lysed horse blood, and 50% human serum. We observed very significant differences in measured MICs (up to 100-fold) for some lipophilic antibiotics, such as the Gram-positive lipoglycopeptide dalbavancin and the Gram-negative lipopeptide polymyxins, and found that nonspecific binding plates can replace the need for surfactant additives. Microtiter plate types and any additives should be specified when reporting broth dilution MIC values, as results can vary dramatically for some classes of antibiotics.


Assuntos
Meios de Cultura/química , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana/instrumentação , Aminoglicosídeos/química , Aminoglicosídeos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Cálcio/farmacologia , Ciprofloxacino/química , Ciprofloxacino/farmacologia , Colistina/química , Colistina/farmacologia , Meios de Cultura/farmacologia , Depsipeptídeos/química , Depsipeptídeos/farmacologia , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Análise Fatorial , Lipoglicopeptídeos/química , Lipoglicopeptídeos/farmacologia , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/metabolismo , Oxacilina/química , Oxacilina/farmacologia , Penicilina G/química , Penicilina G/farmacologia , Plásticos/química , Polimixina B/química , Polimixina B/farmacologia , Polissorbatos/farmacologia , Rifampina/química , Rifampina/farmacologia , Teicoplanina/análogos & derivados , Teicoplanina/química , Teicoplanina/farmacologia , Trimetoprima/química , Trimetoprima/farmacologia , Vancomicina/química , Vancomicina/farmacologia
7.
Pancreatology ; 18(8): 935-944, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30316690

RESUMO

The transient receptor potential TRPM8 ion channel is required for cellular proliferation in pancreatic epithelia and adenocarcinoma. To elucidate the mechanism that mediates the function of TRPM8, we examined its role in the proliferation and invasion of pancreatic cancer (PC) cells. TRPM8 expression increased in both the PC tissues and cell lines; a high TRPM8 expression was correlated with poorer prognosis in patients with PC. In PC cell lines, PACN-1 and BxPC-3, Ca2+ influxes could be evoked by TRPM8; the sensitivity of PC cells to gemcitabine was increased, while the proliferation and invasion of PC cells were suppressed after RNA interference-mediated silencing of TRPM8. The mechanism of TRPM8 in gemcitabine-based chemotherapy was then investigated. The expression and activity of multidrug resistance-associated proteins, P-gp, MRP-2, LRP, was significantly reduced in response to TRPM8 silence. Moreover, TRPM8 knockdown significantly increased hENT1 protein levels and the ratio of Bax/Bcl-2 while decreased the protein levels of RRM1. Thus, TRPM8 is required for PC cell proliferation and invasion and was closely related to the gemcitabine sensitivity of PC. The modulation of TRPM8 expression may help improve treatment response of PC by combining with traditional chemotherapy.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Desoxicitidina/análogos & derivados , Inativação Gênica , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/terapia , Canais de Cátion TRPM/genética , Adulto , Idoso , Cálcio/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Terapia Combinada , Desoxicitidina/uso terapêutico , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Neoplasias Pancreáticas/patologia , Prognóstico , RNA Interferente Pequeno/uso terapêutico , Canais de Cátion TRPM/antagonistas & inibidores
8.
Viruses ; 10(6)2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29844267

RESUMO

Enterococcus faecalis is a commensal opportunistic pathogen found in the intestine, mouth, and vaginal tract of humans. As an invasive pathogen in the oral cavity, E. faecalis is one of the leading causes of periapical endodontic lesions. However, due to the strong biofilm-forming capacity and tolerance of E. faecalis to conventional antibiotics and treatments, limited therapeutic options are available. In the present study, we investigated the activity of ClyR, a chimeric lysin with extended streptococcal lytic spectrum, against planktonic and sessile E. faecalis cells in vitro and in an ex vivo dental model. Our results showed that ClyR has robust and rapid lytic activity against multiple E. faecalis strains, killing >90% planktonic cells within 1 min at a concentration of 50 µg/mL. The biochemical experiments combined with microscopy analysis revealed that ClyR degrades E. faecalis biofilm with high efficacy in a dose-dependent manner, reducing the survival rate to 90% viable bacteria within biofilms at a low dose of 50 µg/mL, which is much better than ampicillin and similar to calcium hydroxide, the extensively used routine intracanal medicament in the treatment of endodontics and dental traumatology. The robust activity of ClyR against both planktonic and sessile E. faecalis suggests the potential of ClyR in treating endodontic infections caused by E. faecalis.


Assuntos
Antibacterianos/farmacologia , Cavidade Pulpar/microbiologia , Enterococcus faecalis/efeitos dos fármacos , Enzimas/farmacologia , Ampicilina/farmacologia , Biofilmes/efeitos dos fármacos , Hidróxido de Cálcio/farmacologia , Cavidade Pulpar/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana
9.
Nat Commun ; 9(1): 22, 2018 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-29295973

RESUMO

The public health threat posed by a looming 'post-antibiotic' era necessitates new approaches to antibiotic discovery. Drug development has typically avoided exploitation of membrane-binding properties, in contrast to nature's control of biological pathways via modulation of membrane-associated proteins and membrane lipid composition. Here, we describe the rejuvenation of the glycopeptide antibiotic vancomycin via selective targeting of bacterial membranes. Peptide libraries based on positively charged electrostatic effector sequences are ligated to N-terminal lipophilic membrane-insertive elements and then conjugated to vancomycin. These modified lipoglycopeptides, the 'vancapticins', possess enhanced membrane affinity and activity against methicillin-resistant Staphylococcus aureus (MRSA) and other Gram-positive bacteria, and retain activity against glycopeptide-resistant strains. Optimised antibiotics show in vivo efficacy in multiple models of bacterial infection. This membrane-targeting strategy has potential to 'revitalise' antibiotics that have lost effectiveness against recalcitrant bacteria, or enhance the activity of other intravenous-administered drugs that target membrane-associated receptors.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Daptomicina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Vancomicina/farmacologia , Animais , Antibacterianos/metabolismo , Antibacterianos/farmacocinética , Bactérias/classificação , Sobrevivência Celular/efeitos dos fármacos , Glicopeptídeos/metabolismo , Células HEK293 , Células Hep G2 , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
10.
Front Neurosci ; 12: 942, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30618571

RESUMO

In this work, we systematically analyzed the effects of various nodal definitions, as determined by a multi-granularity whole-brain segmentation scheme, upon the topological architecture of the human brain functional network using the resting-state functional magnetic resonance imaging data of 19 healthy, young subjects. A number of functional networks were created with their nodes defined according to two types of anatomical definitions (Type I and Type II) each of which consists of five granularity levels of whole brain segmentations with each level linked through ontology-based, hierarchical, structural relationships. Topological properties were computed for each network and then compared across levels within the same segmentation type as well as between Type I and Type II. Certain network architecture patterns were observed in our study: (1) As the granularity changes, the absolute values of each node's nodal degree and nodal betweenness change accordingly but the relative values within a single network do not change considerably; (2) The average nodal degree is generally affected by the sparsity level of the network whereas the other topological properties are more specifically affected by the nodal definitions; (3) Within the same ontology relationship type, as the granularity decreases, the network becomes more efficient at information propagation; (4) The small-worldness that we observe is an intrinsic property of the brain's resting-state functional network, independent of the ontology type and the granularity level. Furthermore, we validated the aforementioned conclusions and measured the reproducibility of this multi-granularity network analysis pipeline using another dataset of 49 healthy young subjects that had been scanned twice.

11.
Neuroscience ; 366: 70-83, 2017 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-29037598

RESUMO

In this paper, by utilizing surface diffeomorphic deformations, we constructed and analyzed subcortical shape morphometric networks in 210 healthy control (HC) subjects and 175 subjects with Alzheimer's disease (AD), aiming to identify AD-induced abnormalities in the subcortical shape network. We quantitatively analyzed pertinent network attributes of the entire network and each node. Further to this, hierarchical analyses were performed; group comparisons were conducted at the structure level first and then the sub-region level. The bilateral amygdalae, hippocampi, as well as the thalamus were all divided into multiple functionally distinct sub-regions. From the structure level analysis, we found significant HC-vs-AD group differences in the average local efficiency and average global efficiency. In addition, the local nodal efficiencies between the right thalamus and all three of the right hippocampus, right amygdala, and left thalamus, as well as that between the left amygdala and left hippocampus, decreased significantly in AD. According to the sub-regional network analyses, we observed significant AD-induced local efficiency decreases between different sub-regions within the right hippocampus itself and between the subiculum of the right hippocampus and the sub-region of the right thalamus connecting to the temporal lobe, indicating a degradation of circuit between the hippocampus, thalamus, and temporal lobe. Statistical comparisons were performed using 40,000 non-parametric permutation tests, with false discovery rate correction employed for multiple comparison correction.


Assuntos
Doença de Alzheimer/patologia , Encéfalo/patologia , Vias Neurais/patologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Tonsila do Cerebelo/diagnóstico por imagem , Tonsila do Cerebelo/patologia , Encéfalo/diagnóstico por imagem , Feminino , Hipocampo/diagnóstico por imagem , Hipocampo/patologia , Humanos , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Tálamo/diagnóstico por imagem , Tálamo/patologia
12.
Int J Ophthalmol ; 10(3): 406-412, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28393032

RESUMO

AIM: To evaluate the morphological changes in anterior segment in Chinese patients with uveal effusion (UE) after the attack of acute primary angle-closure (APAC) using ultrasound biomicroscopy (UBM), and to assess the clinical course and prognosis of the disease. METHODS: In a retrospective case series, 26 eyes in 26 consecutive patients diagnosed with UE after the treatment of intraocular pressure (IOP)-lowering medication for the attack of APAC were enrolled. The unaffected fellow eyes served as controls. The morphological changes were observed by ultrasonography, slit lamp microscopy and gonioscopy. UBM was used to assess the degree and extent of effusion based on the analysis of parameters associated with UE. RESULTS: The mean IOP was 9.2 (SD 2.1) mm Hg at the diagnosis of UE after IOP-lowering medication, while 14.1 (SD, 2.6) mm Hg in the fellow eyes (P=0.000). The anterior chamber depth (ACD) (P=0.000), angle opening distance at 500 µm (AOD500) (P<0.01) and anterior chamber angle (ACA) (P<0.05) were decreased significantly, while ciliary body thickness (CBT) (P<0.05) increased significantly in UE eyes. UE grade analysis showed 7 eyes in grade 1, 9 eyes in grade 2, and 10 eyes in grade 3. Quadrant scores were performed of 4 eyes in 1 quadrant, 3 eyes in 3 quadrants, and 19 eyes in 4 quadrants. There was the positive correlation between grade and quadrant score (r=0.644, P=0.000). The effusion on all eyes were recovered after medication, which mean IOP was 13.9 (SD, 2.8) mm Hg. CONCLUSION: UE is a frequent complication in Chinese patients after the attack of APAC, partially associated with hypotony. The severity of UE is correlation with height of effusion, extent of detachment, and shallower ACD.

13.
Wei Sheng Wu Xue Bao ; 57(1): 121-30, 2017 Jan 04.
Artigo em Chinês | MEDLINE | ID: mdl-29746766

RESUMO

Objective: To study the regulation of sporulation controlled by two-component system (TCS) YvcPQ. Methods: ß-galactosidase experiment was used to verify the regulation of YvcP on kapD expression; bacterial one-hybrid assay, EMSA and RT-qPCR were applied to study the regulation of AbrB on yvcPQ expression; markerless gene deletion coupled with spore count was used to reveal the influence of yvcPQ and kapD expressions on sporulation. Results: transcriptional regulator AbrB up-regulated the expression of yvcPQ; YvcP promoted the expression of kapD to inhibit sporulation. Conclusion: AbrB up-regulated the transcription of yvcPQ operon, then the increased YvcP strengthened the transcriptional acitivation of sporulation inhibitor gene kapD, and subsequently inhibited sporulation.


Assuntos
Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Óperon , Esporos Bacterianos/genética , Esporos Bacterianos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Genética
14.
Biopolymers ; 96(2): 147-57, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20564028

RESUMO

Citropin 1.1, maculatin 1.1, and caerin 1.1 are short antibacterial cationic peptides from the skin glands of the Australian tree frog Litoria species. Several analogues have been synthesized to give a better insight into the relationship between the structure of the peptides and their antibacterial and haemolytic activity. Binding studies using a surface plasmon resonance (SPR) biosensor together with a vesicle-capture sensor chip have been used to investigate selectivity of the peptides and their analogues for 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles, as well as for vesicles made from lipid extracts from Escherichia coli and bovine brain. Data obtained for membrane selectivity using natural lipid extracts show better correlation with minimum inhibitory concentration (MIC) values against Gram-positive bacteria and haemolytic activity than that obtained using synthetic DMPG and DMPC. Electron microscopy and membrane leakage studies using Gram-positive bacteria gave further insight into the membrane disruption properties of the peptides. For maculatin 1.1, it was found that the central proline residue, which is responsible for a bend in the alpha-helical structure, is essential not only for the antibacterial activity but also for binding, and perturbation of membranes. The caerin analogues showed only small variations in their MIC values and membrane binding. In contrast, for citropin 1.1, the analogue replacing the aspartate with a lysine showed the lowest MIC against Gram-positive bacteria and best membrane binding to E. coli lipid extracts, coinciding with an increased hydrophobic moment of the peptide. These data give further insight into these antimicrobial natural products, toward the development and evaluation of these and other analogues as potential antibiotics.


Assuntos
Proteínas de Anfíbios/química , Peptídeos Catiônicos Antimicrobianos/química , Membranas Artificiais , Proteínas de Anfíbios/farmacologia , Animais , Peptídeos Catiônicos Antimicrobianos/farmacologia , Química Encefálica , Bovinos , Escherichia coli/química , Bactérias Gram-Positivas/crescimento & desenvolvimento , Humanos , Ressonância de Plasmônio de Superfície
15.
Zhong Yao Cai ; 33(10): 1545-8, 2010 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-21355189

RESUMO

OBJECTIVE: To determine the contents of the active components, gallic acid and ellagic acid in Geranium carolinianum from different collection time and to define the best collection time for this herb. METHODS: The contents of gallic acid and ellagic acid in each samples of Geranium carolinianum were determined by HPLC. The HPLC method was performed on a Diamonsil C, 8 column (150 mm x 4.6 mm, 5 microm) with acetonitrile-0.1% H3PO4 as mobile phase. The flow rate was 1.0 mL/min, the detection wavelength was 274 nm and the column temperature was 25 degrees C. RESULTS: The calibration curve of gallic acid and ellagic acid were linear in the range of 0.075-5.00 microg (r = 0.9995) and 0.05-2.00 microg (r = 0.9995), respectively. The average recovery of gallic acid and ellagic acid were 99.88% (RSD = 1.19%) and 99.08% (RSD = 2.81%), respectively. CONCLUSION: The content of gallic acid and ellagic acid in Geranium carolinianum both began to increase in flowering stage and increased to the maximum value in immature-fruit stage.


Assuntos
Ácido Elágico/análise , Ácido Gálico/análise , Geranium/química , Plantas Medicinais/química , Antioxidantes/análise , Antioxidantes/química , Antivirais/análise , Antivirais/química , Cromatografia Líquida de Alta Pressão , Geranium/crescimento & desenvolvimento , Componentes Aéreos da Planta/química , Plantas Medicinais/crescimento & desenvolvimento , Reprodutibilidade dos Testes , Estações do Ano
16.
J Pharmacol Exp Ther ; 326(3): 856-63, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18539649

RESUMO

The ability of botulinum toxin to poison cholinergic nerve transmission is a dynamic phenomenon that involves not only the actions of the toxin on the body but also the actions of the body on the toxin. The former has been the subject of intense research, whereas the latter has received almost no attention. Therefore, a series of studies were performed to characterize systemic handling of botulinum toxin. The results indicated that the toxin reaches the general circulation (transcytosis across epithelial cells) without obvious changes in structure or biological activity. The general circulation acts as a holding compartment until there is adequate fractional distribution to neuromuscular junctions to produce blockade of transmission. During its transit through this compartment, the toxin 1) undergoes little biotransformation, 2) does not accumulate significantly in circulating cells, and 3) remains largely in the free state. In naive animals, the t(1/2) for toxin in the general circulation is approximately 10 h, and at any given point in time, there is little uptake in nontarget organs (liver, kidney, heart, and lung). In immunized animals, toxin clearance from the general circulation is rapid, and there is substantial accumulation of antibody-antigen complexes in liver. Thus, enhanced clearance from the circulation is a major mechanism by which active immunization can protect against poisoning.


Assuntos
Circulação Sanguínea/efeitos dos fármacos , Circulação Sanguínea/fisiologia , Toxinas Botulínicas/farmacocinética , Animais , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Coelhos , Ratos , Ratos Sprague-Dawley
17.
Infect Immun ; 75(6): 3043-54, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17371853

RESUMO

Most reports dealing with vaccines against botulinum toxin have focused on the injection route of administration. This is unfortunate, because a mucosal vaccine is likely to be more efficacious for patients and pose fewer risks to health care workers and to the environment. Therefore, efforts were made to generate a mucosal vaccine that provides protection against the botulinum serotypes that typically cause human illness (serotypes A, B, and E). This work demonstrated that carboxy-terminal peptides derived from each of the three serotypes were able to bind to and penetrate human epithelial barriers in vitro, and there was no cross inhibition of membrane binding and transcytosis. The three polypeptides were then tested in vivo as a trivalent vaccine that could be administered to mice by the intranasal route. The results indicated that the mucosal vaccine evoked high secretory titers of immunoglobulin A (IgA), as well as high circulating titers of IgG and IgA, and it also evoked a high level of resistance to challenge with toxin. The immunoglobulin responses and the levels of resistance to challenge were increased by coadministration of adjuvants, such as chitosan and vitamin E. At least three mechanisms were identified to account for the antibody-induced resistance: (i) blockade of toxin absorption across epithelial cells, (ii) enhanced clearance of toxin from the circulation, and (iii) blockade of toxin action at the neuromuscular junction. These results are a compelling demonstration that a mucosal vaccine against multiple serotypes of botulinum toxin has been identified.


Assuntos
Formação de Anticorpos , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/imunologia , Toxinas Botulínicas/administração & dosagem , Animais , Vacinas Bacterianas/química , Toxinas Botulínicas/genética , Toxinas Botulínicas/imunologia , Toxinas Botulínicas Tipo A/administração & dosagem , Toxinas Botulínicas Tipo A/genética , Toxinas Botulínicas Tipo A/imunologia , Células Cultivadas , Vias de Administração de Medicamentos , Camundongos , Membrana Mucosa/imunologia , Sorotipagem
18.
J Pharmacol Exp Ther ; 318(3): 1343-51, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16782822

RESUMO

Botulinum toxin is an extraordinarily potent molecule that has an unusually long duration of action. Despite this, there is little information available on natural mechanisms for metabolism or elimination and virtually no information on pharmacologically induced mechanisms for metabolism and elimination. Therefore, a number of experiments were performed on laboratory animals that addressed two major issues: 1) the effect of blood on the structure, function, and biologic half-life of the toxin, and 2) the effect of neutralizing antibodies on half-life and elimination of circulating toxin. In the first series of studies, the metabolic transformation of toxin was assessed by incubating it in blood for varying lengths of time. At each time point, aliquots were examined to determine the amount of toxin, the structure of toxin, the catalytic activity of toxin, and the neuromuscular blocking activity of toxin. This work demonstrated that blood did not alter any characteristic of the toxin molecule. Experiments were also done in which toxin was administered to mice and rats at doses that produced clinical poisoning. The results demonstrated that the elimination half-life for native (nonmetabolized) toxin in blood and serum was 230 to 260 min. During the second series of studies, the rate of elimination of circulating toxin was studied in the presence of antibodies directed against the carboxyl-terminal half of the toxin molecule. This work demonstrated that neutralizing antibodies 1) enhanced clearance of toxin from the circulation and 2) enhanced tissue accumulation of toxin, particularly in liver and spleen.


Assuntos
Toxinas Botulínicas/farmacocinética , Animais , Toxinas Botulínicas/antagonistas & inibidores , Toxinas Botulínicas/química , Toxinas Botulínicas/toxicidade , Feminino , Meia-Vida , Soros Imunes/imunologia , Taxa de Depuração Metabólica , Camundongos , Ratos , Ratos Sprague-Dawley
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA