RESUMO
Motility is required for many bacterial pathogens to reach and colonize target sites. Vibrio cholerae traverses a thick mucus barrier coating the small intestine to reach the underlying epithelium. We screened a transposon library in motility medium containing mucin to identify factors that influence mucus transit. Lesions in structural genes of the type VI secretion system (T6SS) were among those recovered. Two-dimensional (2D) and 3D single-cell tracking was used to compare the motility behaviors of wild-type cells and a mutant that collectively lacked three essential T6SS structural genes (T6SS-). In the absence of mucin, wild-type and T6SS- cells exhibited similar speeds and run-reverse-flick (RRF) swimming patterns, in which forward-moving cells briefly backtrack before stochastically reorienting (flicking) in a new direction upon resuming forward movement. We show that mucin induced T6SS expression and activity in wild-type bacteria but significantly decreased their swimming speed and flicking, yielding curvilinear or near-surface circular traces for many cells. Conversely, mucin slowed T6SS- cells to a lesser extent, and many continued to flick and produce RRF-like traces. ΔcheY3 cells, which exclusively swim in the forward direction and thus cannot flick, also produced curvilinear traces with or without mucin present and, on occasion, near-surface circular traces in the presence of mucin. The dependence of flicking on swimming speed suggested that mucin-induced T6SS activity further decreased V. cholerae motility and thereby reduced flicking probability during reverse-to-forward transitions. We propose that this encourages cells to continue on their current trajectory rather than reorienting, which may benefit those tracking toward the epithelial surface.IMPORTANCEV. cholerae deploys an arsenal of virulence factors as it attempts to traverse a protective mucus layer and reach the epithelial surface of the distal small intestine. The T6SS used to cull bacterial competition during infection is induced by mucus. We show that this activity may serve an additional purpose by further decreasing motility in the presence of mucin, thereby reducing the probability of speed-dependent, near-perpendicular directional changes. We posit that this encourages cells to maintain course rather than change direction, which may aid those attempting to reach and colonize the epithelial surface.
Assuntos
Proteínas de Bactérias/metabolismo , Cólera/microbiologia , Mucinas/metabolismo , Sistemas de Secreção Tipo VI/metabolismo , Vibrio cholerae/citologia , Vibrio cholerae/metabolismo , Proteínas de Bactérias/genética , Cólera/metabolismo , Regulação Bacteriana da Expressão Gênica , Humanos , Intestino Delgado/metabolismo , Intestino Delgado/microbiologia , Sistemas de Secreção Tipo VI/genética , Vibrio cholerae/genéticaRESUMO
Both infectious viral diseases and cancer have historically been some of the most common causes of death worldwide. The COVID-19 pandemic is a decidedly relevant example of the former. Despite progress having been made over past decades, new and improved techniques are still needed to address the limitations faced by current treatment standards, with mRNA-based therapy emerging as a promising solution. Highly flexible, scalable and cost-effective, mRNA therapy is proving to be a compelling vaccine platform against viruses. Likewise, mRNA vaccines show similar promise against cancer as a platform capable of encoding multiple antigens for a diverse array of cancers, including those that are patient specific as a novel form of personalized medicine. In this review, the molecular mechanisms, biotechnological aspects, and clinical developments of mRNA vaccines against viral infections and cancer are discussed to provide an informative update on the current state of mRNA therapy research.
Assuntos
COVID-19 , Doenças Transmissíveis , Neoplasias , Vírus , COVID-19/prevenção & controle , Humanos , Neoplasias/genética , Neoplasias/terapia , Pandemias , RNA Mensageiro/genética , Vacinas Sintéticas , Vacinas de mRNARESUMO
Glycan-binding protein C-type lectin (CTL), one of the pattern recognition receptors (PRRs), binds to carbohydrates on the surface of pathogens and elicits antimicrobial responses in shrimp innate immunity. The objective was to identify and characterize a novel C-type lectin LvCTL 4.2 in Litopenaeus vannamei. The LvCTL 4.2 protein consisted of a signal peptide at the N terminal and a carbohydrate-recognition domain (CRD) with a mutated mannose-binding (Glu-Pro-Ala; EPA) motif at the C terminal, and thereby has a putative secreted mannose-binding C-type lectin architecture. LvCTL 4.2 was highly expressed in nervous tissue and stomach. Infection with white spot syndrome virus (WSSV) induced expression of LvCTL 4.2 in shrimp stomach at 12 h post infection. Conversely, there was no obvious upregulation in expression of LvCTL 4.2 in stomach or hepatopancreas of shrimp with AHPND (acute hepatopancreas necrosis disease). Pathogen binding assays confirmed recombinant LvCTL 4.2 protein (rLvCTL 4.2) had significant binding ability with the WSSV virion, Gram-negative, and Gram-positive bacteria. Moreover, rLvCTL 4.2 had strong growth inhibition of Vibrio parahaemolyticus. Silencing LvCTL 4.2 suppressed WSSV replication, whereas pretreatment of WSSV with rLvCTL 4.2 facilitated viral replication in vivo. In conclusion, LvCTL 4.2 acted as a PRR that inhibited AHPND-causing bacteria, but facilitated WSSV pathogenesis.
Assuntos
Penaeidae , Vírus da Síndrome da Mancha Branca 1 , Animais , Antibacterianos/metabolismo , Proteínas de Artrópodes , Hepatopâncreas/metabolismo , Imunidade Inata , Lectinas Tipo C/genética , Vírus da Síndrome da Mancha Branca 1/fisiologiaRESUMO
Photonic-crystal (PC) surface-emitting lasers (SELs) with double-hole structure in the square-lattice unit cell were fabricated on GaSb-based type-I InGaAsSb/AlGaAsSb heterostructures. The relative shift of two holes was varied within one half of the lattice period. We measured the lasing wavelengths and threshold pumping densities of 16 PC-SELs and investigated their dependence on the double-hole shift. The experimental results were compared to the simulated wavelengths and threshold gains of four band-edge modes. The measured lasing wavelength did not exhibit switching of band-edge mode; however, the calculated lowest threshold mode switched as the double-hole shift exceeded one quarter of the lattice period. The identification of band-edge lasing mode revealed that modal gain discrimination was dominated over by its mode wavelength separation.
RESUMO
PURPOSE: To evaluate the efficacy of intravitreal bevacizumab with panretinal photocoagulation (PRP) in the treatment of proliferate diabetic retinopathy (PDR) with vitreous hemorrhage (VH). METHODS: Forty cases (40 patients) with PDR and persistent VH were prospectively enrolled, with a follow-up period of 12 months or more. Intravitreal bevacizumab injection (1.25 mg) was given, followed by PRP when visualization of peripheral fundus could be obtained. A second injection was administered 4 weeks to 6 weeks after the first injection if no signs of VH decrease were noted. Vitrectomy was performed if VH persisted >12 weeks. The vitreous clear-up time (VCUT) and the rate of vitrectomy were compared with those in a historical control group (40 eyes in 40 patients) who were treated with conventional methods. RESULTS: Thirty-one eyes had 1 injection and 9 eyes (22.5%) received 2 injections. Vitreous clear-up time in the study and control groups were 11.9 +/- 9.5 weeks and 18.1 +/- 12.7 weeks (P = 0.02), respectively. Rates of required vitrectomy were 10% in the study group and 45% in the control group (P = 0.01). CONCLUSION: One or 2 intravitreal injections of 1.25 mg bevacizumab with PRP are associated with rapid regression of VH and may reduce the need for vitrectomy.
Assuntos
Inibidores da Angiogênese/administração & dosagem , Anticorpos Monoclonais/administração & dosagem , Retinopatia Diabética/tratamento farmacológico , Retinopatia Diabética/cirurgia , Fotocoagulação/métodos , Hemorragia Vítrea , Adolescente , Adulto , Idoso , Anticorpos Monoclonais Humanizados , Bevacizumab , Retinopatia Diabética/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Retina/efeitos dos fármacos , Retina/cirurgia , Resultado do Tratamento , Vitrectomia , Hemorragia Vítrea/tratamento farmacológico , Hemorragia Vítrea/cirurgiaRESUMO
PURPOSE: To investigate the anti-oxidative and anti-inflammatory effects of cilostazol in the ocular tissues of streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced in 6-week-old Wistar rats via peritoneal injections of STZ. The treatment group received cilostazol 18 mg/kg/day for 8 weeks (n = 10), and the diabetic group received phosphate buffer solution (n = 20). The expression of oxidative stress and inflammatory mediators in the ocular tissues was then assessed by reverse-transcription polymerase chain reactions, immunohistochemical (IHC) staining, Western blot analysis, and enzyme-linked immunosorbent assay (ELISA). RESULTS: Reverse-transcription polymerase chain reactions, IHC staining, Western blot analysis, and ELISA showed that cilostazol inhibited mRNA and protein expressions of intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and fractalkine in the retina and aqueous humor (AqH). Consistent with these findings, cilostazol attenuated the activation of nuclear factor-κB (NF-κB) in the diabetic rats. The levels of oxidatively modified DNA (8-OHdG), nitrotyrosine and oxidative lipids (acrolein) were also diminished in the cilostazol-treated group. Chemiluminescence analysis showed that reactive oxygen species (ROS) levels in the AqH was significantly higher in the diabetic rats than in the non-diabetic rats. Treatment with cilostazol significantly reduced the ROS levels in the AqH compared to the diabetic rats. CONCLUSIONS: Our results indicated that cilostazol reduced inflammatory reactions and oxidative stress in diabetic eyes. The anti-inflammatory effects of cilostazol may be indirectly via reducing oxidative stress, inhibiting NF-κB activity, and subsequently decreasing inflammatory mediators. Cilostazol may be beneficial to prevent the progression of diabetic retinopathy.
Assuntos
Cilostazol/uso terapêutico , Diabetes Mellitus Experimental/tratamento farmacológico , Retinopatia Diabética/prevenção & controle , Inflamação/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Inibidores da Fosfodiesterase 3/uso terapêutico , Animais , Humor Aquoso/metabolismo , Glicemia/metabolismo , Western Blotting , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Quimiocina CX3CL1/genética , Quimiocina CX3CL1/metabolismo , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Regulação da Expressão Gênica/fisiologia , Imuno-Histoquímica , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , NF-kappa B/metabolismo , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Retina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , EstreptozocinaRESUMO
Using two advanced sequencing approaches, Illumina and PacBio, we derive the entire Dscam gene from an M2 assembly of the complete Penaeus monodon genome. The P. monodon Dscam (PmDscam) gene is ~266 kbp, with a total of 44 exons, 5 of which are subject to alternative splicing. PmDscam has a conserved architectural structure consisting of an extracellular region with hypervariable Ig domains, a transmembrane domain, and a cytoplasmic tail. We show that, contrary to a previous report, there are in fact 26, 81 and 26 alternative exons in N-terminal Ig2, N-terminal Ig3 and the entirety of Ig7, respectively. We also identified two alternatively spliced exons in the cytoplasmic tail, with transmembrane domains in exon variants 32.1 and 32.2, and stop codons in exon variants 44.1 and 44.2. This means that alternative splicing is involved in the selection of the stop codon. There are also 7 non-constitutive cytoplasmic tail exons that can either be included or skipped. Alternative splicing and the non-constitutive exons together produce more than 21 million isoform combinations from one PmDscam locus in the P. monodon gene. A public-facing database that allows BLAST searches of all 175 exons in the PmDscam gene has been established at http://pmdscam.dbbs.ncku.edu.tw/ .
Assuntos
Processamento Alternativo , Proteínas de Artrópodes/genética , Éxons , Penaeidae/genética , Sequência de Aminoácidos , Animais , Hemócitos/metabolismo , Tecido Nervoso/metabolismo , Filogenia , Homologia de Sequência , Sequenciamento Completo do GenomaRESUMO
PURPOSE: To report an unusual case of advancing wavelike epitheliopathy that recurred at a site opposite to the initially affected site. METHODS: Single interventional case report. This report describes a 50-year-old woman who presented with advancing, wavelike epitheliopathy of her right eye that lasted 2 months. RESULTS: Slit-lamp biomicroscopy revealed wavy, coarse, irregular epithelium extending from the upper limbus to the central cornea. Confocal microscopy revealed abnormal basal epithelial cells with a loss of cellular borders and hyperreflective nuclei. Application of 1% silver nitrate solution onto the superior limbus effectively treated this condition. However, wavy, irregular epithelium was observed 2 years later in the lower limbus. CONCLUSIONS: Advancing wavelike epitheliopathy can occur from the lower limbus and recur from the opposite side of the initial presentation, even after successful treatment with 1% silver nitrate solution.