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1.
Early Hum Dev ; 195: 106056, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38851024

RESUMEN

PURPOSE: The study aimed at scoring Indian preterm infants at three months corrected age on the TIMP and then comparing the scores to the United States age-based population scores. METHODS: After obtaining Ethical clearance, participants meeting the inclusion criteria of 53 infants whose parents consented were screened and recruited (N = 47) at a tertiary care hospital. The TIMP was then administered at three months of corrected age. RESULTS: Data obtained from 47 infants born preterm (Male = 33, Female = 14) at three months corrected age with mean gestational age (34.4 ± 2.36 weeks) and mean birth weight (1.93 ± 0.55 kgs) was analyzed. Indian infants born preterm scored a mean of (98.17 ± 20.90) compared to the US mean of (108 ± 19), suggesting an under-performance. The average scores were lower when comparing the mean of the study group with the US-based age-matched population. CONCLUSION: Motor performance scores of Indian preterm infants were low when compared to their US counterparts. Since there exists a difference in the raw score obtained by Indian Preterm infants compared to the US-based population, it may not be appropriate to categorize the motor development of Indian infants based on the US population scores.

2.
Sci Rep ; 14(1): 14636, 2024 06 25.
Artículo en Inglés | MEDLINE | ID: mdl-38918456

RESUMEN

Centrin1 gene deleted Leishmania donovani parasite (LdCen1-/-) was developed and extensively tested experimentally as an intracellular stage-specific attenuated and immunoprotective live parasite vaccine candidate ex vivo using human PBMCs and in vivo in animals. Here we report manufacturing and pre-clinical evaluation of current Good-Laboratory Practice (cGLP) grade LdCen1-/- parasites, as a prerequisite before proceeding with clinical trials. We screened three batches of LdCen1-/- parasites manufactured in bioreactors under cGLP conditions, for their consistency in genetic stability, attenuation, and safety. One such batch was preclinically tested using human PBMCs and animals (hamsters and dogs) for its safety and protective immunogenicity. The immunogenicity of the CGLP grade LdCen1-/- parasites was similar to one grown under laboratory conditions. The cGLP grade LdCen1-/- parasites were found to be safe and non-toxic in hamsters and dogs even at 3 times the anticipated vaccine dose. When PBMCs from healed visceral leishmaniasis (VL) cases were infected with cGLP LdCen1-/-, there was a significant increase in the stimulation of cytokines that contribute to protective responses against VL. This effect, measured by multiplex ELISA, was greater than that observed in PBMCs from healthy individuals. These results suggest that cGLP grade LdCen1-/- manufactured under cGMP complaint conditions can be suitable for future clinical trials.


Asunto(s)
Eliminación de Gen , Leishmania donovani , Leishmaniasis Visceral , Vacunas Atenuadas , Leishmania donovani/inmunología , Leishmania donovani/genética , Animales , Humanos , Perros , Vacunas Atenuadas/inmunología , Leishmaniasis Visceral/prevención & control , Leishmaniasis Visceral/inmunología , Leishmaniasis Visceral/parasitología , Cricetinae , Vacunas contra la Leishmaniasis/inmunología , Vacunas contra la Leishmaniasis/genética , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Leucocitos Mononucleares/inmunología , Femenino
3.
Nucl Med Commun ; 45(8): 690-701, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38832433

RESUMEN

OBJECTIVES: The objective of this study was to assess receptor expression in metastatic differentiated thyroid carcinoma patients with progressive elevated thyroglobulin and negative iodine scintigraphy, we used 68 Ga-DOTATATE [Gallium-68 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-octreotate (DOTATATE)] (Krenning's score) and 68 Ga-PSMA-11 (Gallium-68 prostate-specific membrane antigen-11) PET-computed tomography (CT) [molecular imaging prostate-specific membrane antigen (miPSMA) score]. Patients with Krenning's score 3 and above and miPSMA score 2 and above were considered to determine the incidence of patients, who would qualify for treatment with 177 Lu-DOTATATE/PSMA [Lutetium-177 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-octreotate (DOTATATE)/prostate-specific membrane antigen]-based therapy. In addition, we compared 68 Ga-DOTATATE and 68 Ga-PSMA-11 PET-CT with 2-deoxy-2-[F-18]fluoroglucose ( 18 F-FDG) PET-CT (using maximum standardized uptake value). MATERIALS AND METHODS: A total of 74 patients with histopathologically proven metastatic differentiated thyroid carcinoma with thyroglobulin elevation and negative iodine scintigraphy syndrome were studied retrospectively. They all had 18 F-FDG, 68 Ga-DOTATATE, and 68 Ga-PSMA-11 PET-CT scans available for undertaking this analysis. The lesions detected by 68 Ga-DOTATATE and 68 Ga-PSMA-11 were evaluated using Krenning's and miPSMA scores. In addition, quantitative comparisons of maximum standardized uptake values for 68 Ga-DOTATATE and 68 Ga-PSMA-11, as well as with 18 F-FDG, were conducted. RESULTS: Patient-wise analysis revealed positivity rates of 40.5% for 68 Ga-DOTATATE, 41.89% for 68 Ga-PSMA-11, and 75.67% for 18 F-FDG. Among the 74 patients, 14 (18.91%) were deemed eligible for 177 Lu-DOTATATE/PSMA-617 therapy based on Krenning's score of 3 and above both/either miPSMA score of 2 and above on 68 Ga-DOTATATE or 68 Ga-PSMA-11 PET-CT. Within this subgroup, seven out of 74 patients (9.45%) were eligible for 177 Lu-DOTATATE therapy, and nine out of 74 patients (12.16%) were eligible for 177 Lu-PSMA-targeted therapy. Four patients were eligible for both therapies. CONCLUSION: Among thyroglobulin elevation and negative iodine scintigraphy patient's subgroup, 9.45% could qualify for 177 Lu-DOTATATE and 12.16% for 177 Lu-PSMA-617. Four were eligible for both therapies. Given the lack of effective therapies, this subset of patients warrants consideration for radionuclide therapy exploration.


Asunto(s)
Ácido Edético , Estudios de Factibilidad , Isótopos de Galio , Radioisótopos de Galio , Compuestos Organometálicos , Tomografía Computarizada por Tomografía de Emisión de Positrones , Humanos , Compuestos Organometálicos/uso terapéutico , Masculino , Ácido Edético/análogos & derivados , Persona de Mediana Edad , Anciano , Femenino , Oligopéptidos , Fluorodesoxiglucosa F18 , Neoplasias de la Tiroides/diagnóstico por imagen , Neoplasias de la Tiroides/radioterapia , Neoplasias de la Tiroides/patología , Adulto , Antígenos de Superficie/metabolismo , Estudios Retrospectivos , Anciano de 80 o más Años , Glutamato Carboxipeptidasa II/metabolismo
4.
Microbiol Spectr ; 12(6): e0402623, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38712926

RESUMEN

Post-kala-azar dermal leishmaniasis (PKDL) patients are a key source of Leishmania donovani parasites, hindering the goal of eliminating visceral leishmaniasis (VL). Monitoring treatment response and parasite susceptibility is essential due to increasing drug resistance. We assessed the drug susceptibility of PKDL isolates (n = 18) from pre-miltefosine (MIL) era (1997-2004) with isolates (n = 16) from the post-miltefosine era (2010-2019) and post-miltefosine treatment relapse isolates (n = 5) towards miltefosine and amphotericin B (AmB) at promastigote stage and towards sodium antimony gluconate (SAG) at amastigote stage. PKDL isolates were examined for mutation in gene-encoding AQP1 transporter, C26882T mutation on chromosome 24, and miltefosine-transporter (MT). PKDL isolates from the post-miltefosine era were significantly more susceptible to SAG than SAG-resistant isolates from the pre-miltefosine era (P = 0.0002). There was no significant difference in the susceptibility of parasites to miltefosine between pre- and post-miltefosine era isolates. The susceptibility of PKDL isolates towards AmB remained unchanged between the pre- and post-miltefosine era. However, the post-miltefosine era isolates had a higher IC50 value towards AmB compared with PKDL relapse isolates. We did not find any association between AQP1 gene sequence variation and susceptibility to SAG, or between miltefosine susceptibility and single nucleotide polymorphisms (SNPs in the MT gene. This study demonstrates that recent isolates of Leishmania have resumed susceptibility to antimonials in vitro. The study also offers significant insights into the intrinsic drug susceptibility of Leishmania parasites over the past two decades, covering the period before the introduction of miltefosine and after its extensive use. IMPORTANCE: Post-kala-azar dermal leishmaniasis (PKDL) patients, a key source of Leishmania donovani parasites, hinder eliminating visceral-leishmaniasis. Assessment of the susceptibility of PKDL isolates to antimony, miltefosine (MIL), and amphotericin-B indicated that recent isolates remain susceptible to antimony, enabling its use with other drugs for treating PKDL.


Asunto(s)
Anfotericina B , Antimonio , Antiprotozoarios , Resistencia a Medicamentos , Leishmania donovani , Leishmaniasis Cutánea , Leishmaniasis Visceral , Fosforilcolina , Humanos , Leishmania donovani/efectos de los fármacos , Leishmania donovani/genética , Leishmania donovani/aislamiento & purificación , Fosforilcolina/análogos & derivados , Fosforilcolina/farmacología , Fosforilcolina/uso terapéutico , Leishmaniasis Visceral/parasitología , Leishmaniasis Visceral/tratamiento farmacológico , Antiprotozoarios/farmacología , Antimonio/farmacología , Antimonio/uso terapéutico , Leishmaniasis Cutánea/parasitología , Leishmaniasis Cutánea/tratamiento farmacológico , Resistencia a Medicamentos/genética , Anfotericina B/farmacología , Pruebas de Sensibilidad Parasitaria , Gluconato de Sodio Antimonio/farmacología , Gluconato de Sodio Antimonio/uso terapéutico , Mutación
5.
Theor Appl Genet ; 137(6): 122, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38713254

RESUMEN

KEY MESSAGE: By deploying a multi-omics approach, we unraveled the mechanisms that might help rice to combat Yellow Stem Borer infestation, thus providing insights and scope for developing YSB resistant rice varieties. Yellow Stem Borer (YSB), Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae), is a major pest of rice, that can lead to 20-60% loss in rice production. Effective management of YSB infestation is challenged by the non-availability of adequate sources of resistance and poor understanding of resistance mechanisms, thus necessitating studies for generating resources to breed YSB resistant rice and to understand rice-YSB interaction. In this study, by using bulk-segregant analysis in combination with next-generation sequencing, Quantitative Trait Loci (QTL) intervals in five rice chromosomes were mapped that could be associated with YSB resistance at the vegetative phase in a resistant rice line named SM92. Further, multiple SNP markers that showed significant association with YSB resistance in rice chromosomes 1, 5, 10, and 12 were developed. RNA-sequencing of the susceptible and resistant lines revealed several genes present in the candidate QTL intervals to be differentially regulated upon YSB infestation. Comparative transcriptome analysis revealed a putative candidate gene that was predicted to encode an alpha-amylase inhibitor. Analysis of the transcriptome and metabolite profiles further revealed a possible link between phenylpropanoid metabolism and YSB resistance. Taken together, our study provides deeper insights into rice-YSB interaction and enhances the understanding of YSB resistance mechanism. Importantly, a promising breeding line and markers for YSB resistance have been developed that can potentially aid in marker-assisted breeding of YSB resistance among elite rice cultivars.


Asunto(s)
Mapeo Cromosómico , Mariposas Nocturnas , Oryza , Sitios de Carácter Cuantitativo , Oryza/genética , Oryza/parasitología , Oryza/inmunología , Animales , Mariposas Nocturnas/fisiología , Polimorfismo de Nucleótido Simple , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Resistencia a la Enfermedad/genética , Genómica/métodos , Fenotipo , Multiómica
6.
Physiol Mol Biol Plants ; 30(4): 665-686, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38737321

RESUMEN

Lodging, a phenomenon characterized by the bending or breaking of rice plants, poses substantial constraints on productivity, particularly during the harvesting phase in regions susceptible to strong winds. The rice strong culm trait is influenced by the intricate interplay of genetic, physiological, epigenetic, and environmental factors. Stem architecture, encompassing morphological and anatomical attributes, alongside the composition of both structural and non-structural carbohydrates, emerges as a critical determinant of lodging resistance. The adaptive response of the rice culm to various biotic and abiotic environmental factors further modulates the propensity for lodging. Advancements in next-generation sequencing technologies have expedited the genetic dissection of lodging resistance, enabling the identification of pertinent genes, quantitative trait loci, and novel alleles. Concurrently, contemporary breeding strategies, ranging from biparental approaches to more sophisticated methods such as multi-parent-based breeding, gene pyramiding, genomic selection, genome-wide association studies, and haplotype-based breeding, offer perspectives on the genetic underpinnings of culm strength. This review comprehensively delves into physiological attributes, culm histology, epigenetic determinants, and gene expression profiles associated with lodging resistance, with a specialized focus on leveraging next-generation sequencing for candidate gene discovery.

9.
Indian J Dermatol ; 69(1): 102-103, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38572030
10.
Vaccine ; 42(13): 3157-3165, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38637211

RESUMEN

BACKGROUND: Introduction of pneumococcal conjugate vaccines (PCVs) reduced the number of cases of pneumococcal disease (PD). However, there is an increase in clinical and economic burden of PD from serotypes that are not part of the existing pneumococcal vaccines, particularly impacting pediatric and elder population. In addition, the regions where the PCV is not available, the disease burden remains high. In this study, immunogenicity and safety of the BE's 14-valent PCV (PNEUBEVAX 14™; BE-PCV-14) containing two additional epidemiologically important serotypes (22F and 33F) was evaluated in infants in comparison to licensed vaccine, Prevenar-13 (PCV-13). METHODS: This is a pivotal phase-3 single blind randomized active-controlled study conducted at 12 sites across India in 6-8 weeks old healthy infants at 6-10-14 weeks dosing schedule to assess immunogenic non-inferiority and safety of a candidate BE-PCV-14. In total, 1290 infants were equally randomized to receive either BE-PCV-14 or PCV-13. Solicited local reactions and systemic events, adverse events (AEs), serious AEs (SAEs), and medically attended AEs (MAAEs) were recorded. Immunogenicity was assessed by measuring anti-PnCPS (anti-pneumococcal capsular polysaccharide) IgG concentration and functional antibody titers through opsonophagocytic activity (OPA), one month after completing three dose schedule. Cross protection to serotype 6A offered by serotype 6B was also assessed in this study. FINDINGS: The safety profile of BE-PCV-14 was comparable to PCV-13 vaccine. Majority of reported AEs were mild in nature. No severe or serious AEs were reported in both the treatment groups. For the twelve common serotypes and for the additional serotypes (22F and 33F) in BE-PCV-14, NI criteria was demonstrated as defined by WHO TRS-977. Primary immunogenicity endpoint was met in terms of IgG immune responses for all 14 serotypesof BE-PCV-14. Moreover, a significant proportion of subjects (69%) seroconverted against serotype 6A, even though this antigen was not present in BE-PCV-14. This indicates that serotype 6B of BE-PCV-14 cross protects serotype 6A. BE-PCV-14 also elicited comparable serotype specific functional OPA immune responses to all the serotypes common to PCV-13. INTERPRETATIONS: BE-PCV-14 was found to be safe and induced robust and functional serotype specific immune responses to all 14 serotypes. It also elicited cross protective immune response against serotype 6B.These findings suggest that BE-PCV-14 can be safely administered to infants and achieve protection against pneumococcal disease caused by serotypes covered in the vaccine. The study was prospectively registered with clinical trial registry of India - CTRI/2020/02/023129.


Asunto(s)
Anticuerpos Antibacterianos , Infecciones Neumocócicas , Vacunas Neumococicas , Streptococcus pneumoniae , Vacunas Conjugadas , Humanos , Vacunas Neumococicas/inmunología , Vacunas Neumococicas/efectos adversos , Vacunas Neumococicas/administración & dosificación , Lactante , India , Anticuerpos Antibacterianos/sangre , Masculino , Vacunas Conjugadas/inmunología , Vacunas Conjugadas/efectos adversos , Vacunas Conjugadas/administración & dosificación , Femenino , Infecciones Neumocócicas/prevención & control , Infecciones Neumocócicas/inmunología , Método Simple Ciego , Streptococcus pneumoniae/inmunología , Inmunogenicidad Vacunal , Serogrupo , Inmunoglobulina G/sangre
11.
Phys Rev Lett ; 132(13): 133801, 2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38613295

RESUMEN

We demonstrate that the time-integrated light intensity transmitted by a coherently driven resonator obeys Lévy's arcsine laws-a cornerstone of extreme value statistics. We show that convergence to the arcsine distribution is algebraic, universal, and independent of nonequilibrium behavior due to nonconservative forces or nonadiabatic driving. We furthermore verify, numerically, that the arcsine laws hold in the presence of frequency noise and in Kerr-nonlinear resonators supporting non-Gaussian states. The arcsine laws imply a weak ergodicity breaking which can be leveraged to enhance the precision of resonant optical sensors with zero energy cost, as shown in our companion manuscript [V. G. Ramesh et al., companion paper, Phys. Rev. Res. (2024).PPRHAI2643-1564]. Finally, we discuss perspectives for probing the possible breakdown of the arcsine laws in systems with memory.

13.
Plant Cell Environ ; 47(7): 2578-2596, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38533652

RESUMEN

Enhancing carbohydrate export from source to sink tissues is considered to be a realistic approach for improving photosynthetic efficiency and crop yield. The rice sucrose transporters OsSUT1, OsSWEET11a and OsSWEET14 contribute to sucrose phloem loading and seed filling. Crucially, Xanthomonas oryzae pv. oryzae (Xoo) infection in rice enhances the expression of OsSWEET11a and OsSWEET14 genes, and causes leaf blight. Here we show that co-overexpression of OsSUT1, OsSWEET11a and OsSWEET14 in rice reduced sucrose synthesis and transport leading to lower growth and yield but reduced susceptibility to Xoo relative to controls. The immunity-related hypersensitive response (HR) was enhanced in the transformed lines as indicated by the increased expression of defence genes, higher salicylic acid content and presence of HR lesions on the leaves. The results suggest that the increased expression of OsSWEET11a and OsSWEET14 in rice is perceived as a pathogen (Xoo) attack that triggers HR and results in constitutive activation of plant defences that are related to the signalling pathways of pathogen starvation. These findings provide a mechanistic basis for the trade-off between plant growth and immunity because decreased susceptibility against Xoo compromised plant growth and yield.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Proteínas de Transporte de Membrana , Oryza , Enfermedades de las Plantas , Inmunidad de la Planta , Proteínas de Plantas , Plantas Modificadas Genéticamente , Ácido Salicílico , Sacarosa , Xanthomonas , Oryza/microbiología , Oryza/genética , Oryza/inmunología , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Xanthomonas/fisiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Sacarosa/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Transporte de Membrana/genética , Ácido Salicílico/metabolismo , Hojas de la Planta/metabolismo , Hojas de la Planta/inmunología
14.
J Pharm Biomed Anal ; 241: 115995, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38309096

RESUMEN

Polysaccharide-based vaccines cannot stimulate long-lasting immune response in infants due to their inability to elicit a T-cell-dependent immune response. This has been addressed using conjugation technology, where conjugates were produced by coupling a carrier protein to polysaccharides using different conjugation chemistries, such as cyanylation, reductive amination, ethylene diamine reaction, and others. Many glycoconjugate vaccines that are manufactured using different conjugation technologies are already in the market for neonates, infants and young children (e.g., Haemophilus influenzae type-b, Streptococcus pneumoniae and Neisseria meningitidis vaccines), and all of them elicit a T-cell dependent immune response. To manufacture glycoconjugate vaccines, the capsular polysaccharide is first activated by converting its hydroxyl groups to aldehyde-, cyanyl-, or cyanate ester groups, depending on the conjugation chemistry selected. The oxidized and reduced aldehyde functional groups of the polysaccharides are subsequently reacted with the amino groups of carrier protein by reductive amination to form a stable amide bond. In CDAP-based conjugation, the polysaccharide -OH groups are activated to form cyanyl-, or cyanate ester groups to react with the amino groups of carrier protein and forms an isourea bond. Understanding the extent of polysaccharide activation/modification is essential since it directly influences the molar mass of the conjugate, its stability, and the immunogenicity of the product. Reported methods are available to estimate the aldehyde groups of polysaccharides generated by reductive amination. However, no method is available to quantify the cyanyl or cyanate ester (-OCN) groups generated by cyanylation with 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP). We report a novel strategy using an O-phthalaldehyde (OPA) derivatization process followed by size-exclusion chromatography (SEC) high-performance liquid chromatography (HPLC) separation and UV detection. The cyanate ester groups on the activated polysaccharide directly reveal the extent of polysaccharide activation/modification and the residual activated groups in the purified conjugates. This method would be useful for conjugate vaccine manufacturing using CDAP chemistry.


Asunto(s)
Polisacáridos Bacterianos , o-Ftalaldehído , Lactante , Niño , Recién Nacido , Humanos , Preescolar , Vacunas Conjugadas/química , Proteínas Portadoras , Glicoconjugados , Cianatos , Ésteres , Anticuerpos Antibacterianos
15.
Cell Rep ; 43(2): 113683, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38261512

RESUMEN

Microglia are implicated as primarily detrimental in pain models; however, they exist across a continuum of states that contribute to homeostasis or pathology depending on timing and context. To clarify the specific contribution of microglia to pain progression, we take advantage of a temporally controlled transgenic approach to transiently deplete microglia. Unexpectedly, we observe complete resolution of pain coinciding with microglial repopulation rather than depletion. We find that repopulated mouse spinal cord microglia are morphologically distinct from control microglia and exhibit a unique transcriptome. Repopulated microglia from males and females express overlapping networks of genes related to phagocytosis and response to stress. We intersect the identified mouse genes with a single-nuclei microglial dataset from human spinal cord to identify human-relevant genes that may ultimately promote pain resolution after injury. This work presents a comprehensive approach to gene discovery in pain and provides datasets for the development of future microglial-targeted therapeutics.


Asunto(s)
Microglía , Transcriptoma , Masculino , Femenino , Ratones , Humanos , Animales , Transcriptoma/genética , Dolor/genética , Dolor/patología , Médula Espinal/patología , Fagocitosis/genética
16.
18.
Sci Rep ; 14(1): 1155, 2024 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-38212384

RESUMEN

It is well known in the field of materials science that a substance's longevity is significantly influenced by its environment. Everything begins with the initial contact on a material's surface. This influence will then deteriorate and have an extended negative impact on the strength of the material. In this study, the effect of natural weathering in tropical climates on magnetorheological elastomer (MRE) was investigated through microstructural evaluation to understand the aging behavior of the environmentally exposed MRE. To understand and elucidate the process, MREs made of silicone rubber and 70 wt% micron-sized carbonyl iron particles were prepared and exposed to the natural weathering of a tropical climate for 90 days. The MRE samples were then mechanically tensile tested, which revealed that Young's modulus increased, while elongation at break decreased. Surface degradation due to weathering was suspected to be the primary cause of this condition. Using scanning electron microscopy (SEM), the degradation of MRE was investigated as a function of morphological evidence. Upon examination through SEM, it was noted that the weathering effects on the morphology of the exposed samples showed distinct characteristics on the degraded surfaces of the MRE, including numerous microvoids, cavities, and microcracks. While these features were not prominent for the MRE itself, they bear resemblance to the effects observed in similar materials like rubber and elastomer. An atomic force microscope (AFM) is used to investigate the surface topography and local degradation conditions. This observation revealed a distinctive degradation characteristic of the MRE in connection to natural weathering in tropical climates. The surface damage of the MRE samples became severe and inhomogeneous during the environmental aging process, and degradation began from the exposed MRE surface, causing the mechanical characteristics of the MRE to significantly change.

19.
Nature ; 626(7999): 574-582, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38086421

RESUMEN

The intrinsic mechanisms that regulate neurotoxic versus neuroprotective astrocyte phenotypes and their effects on central nervous system degeneration and repair remain poorly understood. Here we show that injured white matter astrocytes differentiate into two distinct C3-positive and C3-negative reactive populations, previously simplified as neurotoxic (A1) and neuroprotective (A2)1,2, which can be further subdivided into unique subpopulations defined by proliferation and differential gene expression signatures. We find the balance of neurotoxic versus neuroprotective astrocytes is regulated by discrete pools of compartmented cyclic adenosine monophosphate derived from soluble adenylyl cyclase and show that proliferating neuroprotective astrocytes inhibit microglial activation and downstream neurotoxic astrocyte differentiation to promote retinal ganglion cell survival. Finally, we report a new, therapeutically tractable viral vector to specifically target optic nerve head astrocytes and show that raising nuclear or depleting cytoplasmic cyclic AMP in reactive astrocytes inhibits deleterious microglial or macrophage cell activation and promotes retinal ganglion cell survival after optic nerve injury. Thus, soluble adenylyl cyclase and compartmented, nuclear- and cytoplasmic-localized cyclic adenosine monophosphate in reactive astrocytes act as a molecular switch for neuroprotective astrocyte reactivity that can be targeted to inhibit microglial activation and neurotoxic astrocyte differentiation to therapeutic effect. These data expand on and define new reactive astrocyte subtypes and represent a step towards the development of gliotherapeutics for the treatment of glaucoma and other optic neuropathies.


Asunto(s)
Astrocitos , Neuroprotección , Adenilil Ciclasas/metabolismo , Astrocitos/citología , Astrocitos/enzimología , Astrocitos/metabolismo , Diferenciación Celular , Núcleo Celular/metabolismo , Supervivencia Celular , AMP Cíclico/metabolismo , Citoplasma/metabolismo , Macrófagos/metabolismo , Macrófagos/patología , Microglía/metabolismo , Microglía/patología , Traumatismos del Nervio Óptico/metabolismo , Traumatismos del Nervio Óptico/patología , Traumatismos del Nervio Óptico/terapia , Células Ganglionares de la Retina/citología , Células Ganglionares de la Retina/metabolismo , Sustancia Blanca/metabolismo , Sustancia Blanca/patología , Glaucoma/patología , Glaucoma/terapia
20.
Enzyme Microb Technol ; 174: 110372, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38104475

RESUMEN

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight disease in rice. As a part of its virulence repertoire, Xoo secretes a cell wall degrading enzyme Cellobiosidase (CbsA), which is a critical virulence factor and also a determinant of tissue specificity. CbsA protein is made up of an N-terminal catalytic domain and a C-terminal fibronectin type III domain. According to the CAZy classification, the catalytic domain of CbsA protein belongs to the glycosyl hydrolase-6 (GH6) family that performs acid-base catalysis. However, the identity of the catalytic acid and the catalytic base of CbsA is not known. Based on the available structural and biochemical data, we identified putative catalytic residues and probed them by site-directed mutagenesis. Intriguingly, the biochemical analysis showed that none of the mutations abolishes the catalytic activity of CbsA, an observation that is contrary to other GH6 family members. All the mutants exhibited altered enzymatic activity and caused significant virulence deficiency in Xoo emphasising the requirement of specific exoglucanase activity of wild-type CbsA for virulence on rice. Our study highlights the need for further studies and the detailed characterisation of bacterial exoglucanases.


Asunto(s)
Oryza , Xanthomonas , Virulencia/genética , Oryza/metabolismo , Dominio Catalítico , Xanthomonas/genética , Xanthomonas/metabolismo , Enfermedades de las Plantas/microbiología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica
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