Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 470
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Cell ; 187(1): 62-78.e20, 2024 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-38096822

RESUMEN

The microbiota influences intestinal health and physiology, yet the contributions of commensal protists to the gut environment have been largely overlooked. Here, we discover human- and rodent-associated parabasalid protists, revealing substantial diversity and prevalence in nonindustrialized human populations. Genomic and metabolomic analyses of murine parabasalids from the genus Tritrichomonas revealed species-level differences in excretion of the metabolite succinate, which results in distinct small intestinal immune responses. Metabolic differences between Tritrichomonas species also determine their ecological niche within the microbiota. By manipulating dietary fibers and developing in vitro protist culture, we show that different Tritrichomonas species prefer dietary polysaccharides or mucus glycans. These polysaccharide preferences drive trans-kingdom competition with specific commensal bacteria, which affects intestinal immunity in a diet-dependent manner. Our findings reveal unappreciated diversity in commensal parabasalids, elucidate differences in commensal protist metabolism, and suggest how dietary interventions could regulate their impact on gut health.


Asunto(s)
Microbioma Gastrointestinal , Parabasalidea , Polisacáridos , Animales , Humanos , Ratones , Fibras de la Dieta , Intestino Delgado/metabolismo , Polisacáridos/metabolismo , Parabasalidea/metabolismo , Carbohidratos de la Dieta/metabolismo , Biodiversidad
2.
Cell ; 176(1-2): 127-143.e24, 2019 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-30633903

RESUMEN

DNA damage provokes mutations and cancer and results from external carcinogens or endogenous cellular processes. However, the intrinsic instigators of endogenous DNA damage are poorly understood. Here, we identify proteins that promote endogenous DNA damage when overproduced: the DNA "damage-up" proteins (DDPs). We discover a large network of DDPs in Escherichia coli and deconvolute them into six function clusters, demonstrating DDP mechanisms in three: reactive oxygen increase by transmembrane transporters, chromosome loss by replisome binding, and replication stalling by transcription factors. Their 284 human homologs are over-represented among known cancer drivers, and their RNAs in tumors predict heavy mutagenesis and a poor prognosis. Half of the tested human homologs promote DNA damage and mutation when overproduced in human cells, with DNA damage-elevating mechanisms like those in E. coli. Our work identifies networks of DDPs that provoke endogenous DNA damage and may reveal DNA damage-associated functions of many human known and newly implicated cancer-promoting proteins.


Asunto(s)
Daño del ADN/genética , Daño del ADN/fisiología , Reparación del ADN/fisiología , Proteínas Bacterianas/metabolismo , Inestabilidad Cromosómica/fisiología , Replicación del ADN/fisiología , Proteínas de Unión al ADN/metabolismo , Escherichia coli/metabolismo , Inestabilidad Genómica , Humanos , Proteínas de Transporte de Membrana/fisiología , Mutagénesis , Mutación , Factores de Transcripción/metabolismo
3.
Annu Rev Biochem ; 86: 357-386, 2017 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-28654328

RESUMEN

A wide range of phylogenetically diverse microorganisms couple the reductive dehalogenation of organohalides to energy conservation. Key enzymes of such anaerobic catabolic pathways are corrinoid and Fe-S cluster-containing, membrane-associated reductive dehalogenases. These enzymes catalyze the reductive elimination of a halide and constitute the terminal reductases of a short electron transfer chain. Enzymatic and physiological studies revealed the existence of quinone-dependent and quinone-independent reductive dehalogenases that are distinguishable at the amino acid sequence level, implying different modes of energy conservation in the respective microorganisms. In this review, we summarize current knowledge about catabolic reductive dehalogenases and the electron transfer chain they are part of. We review reaction mechanisms and the role of the corrinoid and Fe-S cluster cofactors and discuss physiological implications.


Asunto(s)
Proteínas Bacterianas/química , Chloroflexi/enzimología , Coenzimas/química , Corrinoides/química , Halógenos/química , Oxidorreductasas/química , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Benzoquinonas/química , Benzoquinonas/metabolismo , Biocatálisis , Chloroflexi/química , Chloroflexi/genética , Coenzimas/metabolismo , Corrinoides/metabolismo , Transporte de Electrón , Metabolismo Energético , Expresión Génica , Halógenos/metabolismo , Cinética , Modelos Moleculares , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Filogenia , Especificidad por Sustrato , Vitamina B 12/química , Vitamina B 12/metabolismo
4.
Mol Cell ; 83(10): 1677-1692.e8, 2023 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-37207626

RESUMEN

PERIOD (PER) and Casein Kinase 1δ regulate circadian rhythms through a phosphoswitch that controls PER stability and repressive activity in the molecular clock. CK1δ phosphorylation of the familial advanced sleep phase (FASP) serine cluster embedded within the Casein Kinase 1 binding domain (CK1BD) of mammalian PER1/2 inhibits its activity on phosphodegrons to stabilize PER and extend circadian period. Here, we show that the phosphorylated FASP region (pFASP) of PER2 directly interacts with and inhibits CK1δ. Co-crystal structures in conjunction with molecular dynamics simulations reveal how pFASP phosphoserines dock into conserved anion binding sites near the active site of CK1δ. Limiting phosphorylation of the FASP serine cluster reduces product inhibition, decreasing PER2 stability and shortening circadian period in human cells. We found that Drosophila PER also regulates CK1δ via feedback inhibition through the phosphorylated PER-Short domain, revealing a conserved mechanism by which PER phosphorylation near the CK1BD regulates CK1 kinase activity.


Asunto(s)
Relojes Circadianos , Proteínas Circadianas Period , Animales , Humanos , Fosforilación , Retroalimentación , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Quinasa de la Caseína I/genética , Quinasa de la Caseína I/metabolismo , Ritmo Circadiano/genética , Drosophila/metabolismo , Serina/metabolismo , Mamíferos/metabolismo
5.
Cell ; 159(2): 253-66, 2014 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-25284151

RESUMEN

To study how microbes establish themselves in a mammalian gut environment, we colonized germ-free mice with microbial communities from human, zebrafish, and termite guts, human skin and tongue, soil, and estuarine microbial mats. Bacteria from these foreign environments colonized and persisted in the mouse gut; their capacity to metabolize dietary and host carbohydrates and bile acids correlated with colonization success. Cohousing mice harboring these xenomicrobiota or a mouse cecal microbiota, along with germ-free "bystanders," revealed the success of particular bacterial taxa in invading guts with established communities and empty gut habitats. Unanticipated patterns of ecological succession were observed; for example, a soil-derived bacterium dominated even in the presence of bacteria from other gut communities (zebrafish and termite), and human-derived bacteria colonized germ-free bystander mice before mouse-derived organisms. This approach can be generalized to address a variety of mechanistic questions about succession, including succession in the context of microbiota-directed therapeutics.


Asunto(s)
Bacterias/clasificación , Bacterias/crecimiento & desarrollo , Tracto Gastrointestinal/microbiología , Ratones/microbiología , Animales , Bacterias/metabolismo , Ecosistema , Estuarios , Vida Libre de Gérmenes , Humanos , Isópteros/microbiología , Interacciones Microbianas , Piel/microbiología , Microbiología del Suelo , Simbiosis , Lengua/microbiología , Pez Cebra/microbiología
6.
Mol Cell ; 68(5): 926-939.e4, 2017 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-29153391

RESUMEN

Bacterial group II intron reverse transcriptases (RTs) function in both intron mobility and RNA splicing and are evolutionary predecessors of retrotransposon, telomerase, and retroviral RTs as well as the spliceosomal protein Prp8 in eukaryotes. Here we determined a crystal structure of a full-length thermostable group II intron RT in complex with an RNA template-DNA primer duplex and incoming deoxynucleotide triphosphate (dNTP) at 3.0-Å resolution. We find that the binding of template-primer and key aspects of the RT active site are surprisingly different from retroviral RTs but remarkably similar to viral RNA-dependent RNA polymerases. The structure reveals a host of features not seen previously in RTs that may contribute to distinctive biochemical properties of group II intron RTs, and it provides a prototype for many related bacterial and eukaryotic non-LTR retroelement RTs. It also reveals how protein structural features used for reverse transcription evolved to promote the splicing of both group II and spliceosomal introns.


Asunto(s)
Proteínas Bacterianas/química , Evolución Molecular , Empalme del ARN , ADN Polimerasa Dirigida por ARN/química , Temperatura , Transcripción Genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Estabilidad de Enzimas , Intrones , Modelos Moleculares , Conformación de Ácido Nucleico , Ácidos Nucleicos Heterodúplex/química , Ácidos Nucleicos Heterodúplex/genética , Ácidos Nucleicos Heterodúplex/metabolismo , Unión Proteica , Desnaturalización Proteica , Dominios y Motivos de Interacción de Proteínas , ARN/química , ARN/genética , ARN/metabolismo , ADN Polimerasa Dirigida por ARN/genética , ADN Polimerasa Dirigida por ARN/metabolismo , Retroelementos , Empalmosomas/química , Empalmosomas/enzimología , Empalmosomas/genética , Relación Estructura-Actividad
7.
Insect Mol Biol ; 33(3): 185-194, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38251981

RESUMEN

The hAT family transposable element, hopper, was originally discovered as a defective 3120-bp full-length element in a wild-type strain of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), and subsequently a functional 3131-bp element, hopperBdwe, was isolated from a white eye mutant strain. The latter study showed that closely related elements exist in melonfly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), a closely related subgenus, suggesting that hopper could have a widespread presence in the Bactrocera genus. To further understand the distribution of hopper within and beyond the B. dorsalis species complex, primer pairs from hopperBdwe and its adjacent genomic insertion site were used to survey the presence and relatedness of hopper in five species within the complex and four species beyond the complex. Based on sequence identity of a 1.94 kb internal nucleotide sequence, the closest relationships were with mutated elements from B. dorsalis s.s. and species synonymized with B. dorsalis including B. papayae, B. philippinensis and B. invadens, ranging in identity between 88.4% and 99.5%. Notably, Bactrocera carambolae (Drew & Hancock) (Diptera: Tephritidae), which is most closely related to B. dorsalis beyond the synonymized species, shared hopper identities of 97.3%-99.5%. Beyond the B. dorsalis complex, Z. cucurbitae, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) and Bactrocera zonata (Saunders) (Diptera: Tephritidae) shared identities of 83.1%-97.1%, while hopper was absent from the Bactrocera oleae (Gmelin) (Diptera: Tephritidae) strain tested. While the functional autonomous hopperBdwe element was not detected in these species, another closely related hopper element isolated from a B. dorsalis genetic sexing strain has an uninterrupted transposase open reading frame. The discontinuous presence of hopper in the Bactrocera genus has implications for its use for genomic manipulation and understanding the phylogenetic relationship of these species.


Asunto(s)
Elementos Transponibles de ADN , Filogenia , Tephritidae , Animales , Tephritidae/genética , Secuencia de Bases , Datos de Secuencia Molecular
8.
Proc Natl Acad Sci U S A ; 118(16)2021 04 20.
Artículo en Inglés | MEDLINE | ID: mdl-33879571

RESUMEN

Most microorganisms in nature spend the majority of time in a state of slow or zero growth and slow metabolism under limited energy or nutrient flux rather than growing at maximum rates. Yet, most of our knowledge has been derived from studies on fast-growing bacteria. Here, we systematically characterized the physiology of the methanogenic archaeon Methanococcus maripaludis during slow growth. M. maripaludis was grown in continuous culture under energy (formate)-limiting conditions at different dilution rates ranging from 0.09 to 0.002 h-1, the latter corresponding to 1% of its maximum growth rate under laboratory conditions (0.23 h-1). While the specific rate of methanogenesis correlated with growth rate as expected, the fraction of cellular energy used for maintenance increased and the maintenance energy per biomass decreased at slower growth. Notably, proteome allocation between catabolic and anabolic pathways was invariant with growth rate. Unexpectedly, cells maintained their maximum methanogenesis capacity over a wide range of growth rates, except for the lowest rates tested. Cell size, cellular DNA, RNA, and protein content as well as ribosome numbers also were largely invariant with growth rate. A reduced protein synthesis rate during slow growth was achieved by a reduction in ribosome activity rather than via the number of cellular ribosomes. Our data revealed a resource allocation strategy of a methanogenic archaeon during energy limitation that is fundamentally different from commonly studied versatile chemoheterotrophic bacteria such as E. coli.


Asunto(s)
Metabolismo Energético/fisiología , Methanococcus/crecimiento & desarrollo , Methanococcus/metabolismo , Aclimatación/fisiología , Archaea/genética , Biomasa , Carbono/metabolismo , Regulación de la Expresión Génica Arqueal/genética , Hidrógeno/metabolismo , Metano/metabolismo , Methanococcus/fisiología , Biología de Sistemas/métodos
9.
J Food Sci Technol ; 61(2): 220-229, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38196715

RESUMEN

Camel (Camelus dromedarius and (Camelus bactrianus) are commonly domesticated in the arid and semi-arid regions because they are well adapted to live in harsh climatic conditions. Camel milk is widely consumed in these regions due to its high nutritional value and medicinal properties. It is rich in protein, minerals and vitamins. Moreover, it possesses therapeutic properties such as anti-microbial, anti-oxidants, anti-viral and anti-cancer. Camel milk can be processed into value added products with the aim of extending shelf life and diversifying its usage. However, there are various challenges experienced in processing of camel milk products. This study aims at reviewing published literature on camel milk products processing, processing challenges, the available solutions and applications. To achieve these aims, literature search was carried out using narrative methodology. Literature review provided information concerning processing of camel milk products, the challenges, how to overcome these processing challenges and applications. From this review of literature on camel milk products it can be concluded that it's possible to process these products with some challenges but scientific and technological solutions are available that are improving over time.

10.
Phys Rev Lett ; 130(25): 251901, 2023 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-37418716

RESUMEN

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510 GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510 GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02

Asunto(s)
Alimentos , Fotones , Movimiento (Física)
11.
Genetica ; 151(3): 215-223, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37300797

RESUMEN

The sterile insect technique (SIT) is a highly effective biologically-based method for the population suppression of highly invasive insect pests of medical and agricultural importance. The efficacy of SIT could be significantly enhanced, however, by improved methods of male sterilization that avoid the fitness costs of irradiation. An alternative sterilization method is possible by gene-editing that targets genes essential for sperm maturation and motility, rendering them nonfunctional, similar to the CRISPR-Cas9 targeting of ß2-tubulin in the genetic model system, Drosophila melanogaster. However, since genetic strategies for sterility are susceptible to breakdown or resistance in mass-reared populations, alternative targets for sterility are important for redundancy or strain replacement. Here we have identified and characterized the sequence and transcriptional expression of two genes in a Florida strain of Drosophila suzukii, that are cognates of the D. melanogaster spermatocyte-specific genes wampa and Prosalpha6T. Wampa encodes a coiled-coil dynein subunit required for axonemal assembly, and the proteasome subunit gene, Prosalpha6T, is required for spermatid individualization and nuclear maturation. The reading frames of these genes differed from their NCBI database entries derived from a D. suzukii California strain by 44 and 8 nucleotide substitutions/polymorphisms, respectively, though all substitutions were synonymous resulting in identical peptide sequences. Expression of both genes is predominant in the male testis, and they share similar transcriptional profiles in adult males with ß2-tubulin. Their amino acid sequences are highly conserved in dipteran species, including pest species subject to SIT control, supporting their potential use in targeted male sterilization strategies.


Asunto(s)
Drosophila , Infertilidad , Animales , Masculino , Drosophila/genética , Drosophila melanogaster/genética , Tubulina (Proteína)/genética , Semen , Espermatogénesis/genética
12.
J Biol Chem ; 297(2): 100971, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34280434

RESUMEN

Reverse transcriptases (RTs) can switch template strands during complementary DNA synthesis, enabling them to join discontinuous nucleic acid sequences. Template switching (TS) plays crucial roles in retroviral replication and recombination, is used for adapter addition in RNA-Seq, and may contribute to retroelement fitness by increasing evolutionary diversity and enabling continuous complementary DNA synthesis on damaged templates. Here, we determined an X-ray crystal structure of a TS complex of a group II intron RT bound simultaneously to an acceptor RNA and donor RNA template-DNA primer heteroduplex with a 1-nt 3'-DNA overhang. The structure showed that the 3' end of the acceptor RNA binds in a pocket formed by an N-terminal extension present in non-long terminal repeat-retroelement RTs and the RT fingertips loop, with the 3' nucleotide of the acceptor base paired to the 1-nt 3'-DNA overhang and its penultimate nucleotide base paired to the incoming dNTP at the RT active site. Analysis of structure-guided mutations identified amino acids that contribute to acceptor RNA binding and a phenylalanine residue near the RT active site that mediates nontemplated nucleotide addition. Mutation of the latter residue decreased multiple sequential template switches in RNA-Seq. Our results provide new insights into the mechanisms of TS and nontemplated nucleotide addition by RTs, suggest how these reactions could be improved for RNA-Seq, and reveal common structural features for TS by non-long terminal repeat-retroelement RTs and viral RNA-dependent RNA polymerases.


Asunto(s)
Cristalografía por Rayos X/métodos , ADN Complementario/genética , Geobacillus stearothermophilus/enzimología , Intrones , ARN Bacteriano/genética , ADN Polimerasa Dirigida por ARN/química , Retroelementos/genética , Geobacillus stearothermophilus/química , Modelos Moleculares , ADN Polimerasa Dirigida por ARN/metabolismo , Moldes Genéticos
13.
Environ Sci Technol ; 56(22): 16073-16081, 2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-36260660

RESUMEN

Microbial electrosynthesis (MES) of acetate is a process using electrical energy to reduce CO2 to acetic acid in an integrated bioelectrochemical system. MES powered by excess renewable electricity produces carbon-neutral acetate while benefitting from inexpensive but intermittent energy sources. Interruptions in electricity supply also cause energy limitation and starvation of the microbial cells performing MES. Here, we studied the effect of intermittent electricity supply on the performance of hydrogen-mediated MES of acetate. Thermoanaerobacter kivui produced acetic acid for more than 4 months from intermittent electricity supplied in 12 h on-off cycles in a semicontinuously-fed MES system. After current interruptions, hydrogen utilization and acetate synthesis rates were severely diminished. They did not recover to the steady-state rates of continuous MES within the 12 h current-on period under most conditions. Accumulating high product (acetate) concentration exacerbated this effect and prolonged recovery. However, supply of a low background current of 1-5% of the maximum current during "off-times" reduced the impact of current interruptions on subsequent MES performance. This study presents sustained MES at a rate of up to 2 mM h-1 acetate at an average concentration of 60-90 mM by a pure thermophilic microbial culture powered by intermittent electricity. We identified product inhibition of accumulating acetic acid as a key challenge to improving the efficiency of intermittently powered MES.


Asunto(s)
Dióxido de Carbono , Electricidad , Electrodos , Hidrógeno , Ácido Acético
14.
BMC Geriatr ; 22(1): 330, 2022 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-35428191

RESUMEN

OBJECTIVES: To investigate whether social trust is associated with more stress symptoms among middle-aged and older adults in six East and Southeast Asia regions during the COVID-19 pandemic. METHODS: This multi-region study used cross-sectional survey data collected in May 2020. Participants were a probability-based internet sample of adults aged 55 or older. RESULTS: Government trust was negatively associated with stress in Singapore and South Korea. Higher levels of health care trust were significantly associated with less stress in Singapore and Taiwan. Trust in neighbors was associated with a higher likelihood of stress in Hong Kong and a lower likelihood in Singapore. Social trust was not associated with stress in Japan or Thailand. DISCUSSION: Findings suggest the level of social trust in relation to stress substantially varied by region. Interventions to strengthen trust during COVID-19 and other major health crises need to be tailored to fit regions' unique circumstances.


Asunto(s)
COVID-19 , Anciano , COVID-19/epidemiología , Estudios Transversales , Hong Kong/epidemiología , Humanos , Persona de Mediana Edad , Pandemias , Confianza
15.
Br J Neurosurg ; 36(4): 494-500, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35264032

RESUMEN

PURPOSE: Vision loss following surgery for pituitary adenoma is poorly described in the literature and cannot be reliably predicted with current prognostic models. Detailed characterization of this population is warranted to further understand the factors that predispose a minority of patients to post-operative vision loss. MATERIALS AND METHODS: The medical records of 587 patients who underwent endoscopic transsphenoidal surgery at the Mount Sinai Medical Centre between January 2013 and August 2018 were reviewed. Patients who experienced post-operative vision deterioration, defined by reduced visual acuity, worsened VFDs, or new onset of blurry vision, were identified and analysed. RESULTS: Eleven out of 587 patients who received endoscopic surgery for pituitary adenoma exhibited post-operative vision deterioration. All eleven patients presented with preoperative visual impairment (average duration of 13.1 months) and pre-operative optic chiasm compression. Seven patients experienced visual deterioration within 24 h of surgery. The remaining four patients experienced delayed vision loss within one month of surgery. Six patients had complete blindness in at least one eye, one patient had complete bilateral blindness. Four patients had reduced visual acuity compared with preoperative testing, and four patients reported new-onset blurriness that was not present before surgery. High rates of graft placement (10/11 patients) and opening of the diaphragma sellae (9/11 patients) were found in this series. Four patients had hematomas and four patients had another significant post-operative complication. CONCLUSIONS: While most patients with pituitary adenoma experience favourable ophthalmological outcomes following endoscopic transsphenoidal surgery, a subset of patients exhibit post-operative vision deterioration. The present study reports surgical and disease features of this population to further our understanding of factors that may underlie vision loss following pituitary adenoma surgery. Graft placement and opening of the diaphragma sellae may be important risk factors in vision loss following ETS and should be an area of future investigation.


Asunto(s)
Adenoma , Neoplasias Hipofisarias , Adenoma/complicaciones , Adenoma/cirugía , Ceguera/etiología , Humanos , Imagen por Resonancia Magnética , Neoplasias Hipofisarias/complicaciones , Neoplasias Hipofisarias/cirugía , Estudios Retrospectivos , Resultado del Tratamiento , Trastornos de la Visión/etiología
16.
Br J Neurosurg ; 36(1): 79-85, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32538686

RESUMEN

OBJECT: The authors performed an extensive comparison between patients treated with open versus an endoscopic approach for skull base malignancy with emphasis on surgical outcomes. METHODS: A single-institution retrospective review of 60 patients who underwent surgery for skull base malignancy between 2009 and 2018 was performed. Disease features, surgical resection, post-operative morbidities, adjuvant treatment, recurrence, and survival rates were compared between 30 patients who received purely open surgery and 30 patients who underwent purely endoscopic resection for a skull base malignancy. RESULTS: Of the 60 patients with skull base malignancy, 30 underwent open resection and 30 underwent endoscopic resection. The most common hisotype for endoscopic resection was squamous cell carcinoma (26.7%), olfactory neuroblastoma (16.7%), and sarcoma (10.0%), and 43.3%, 13.3%, and 10.0% for the open resection cohort, respectively. There were no statistical differences in gross total resection, surgical-associated cranial neuropathy, or ability to achieve negative margins between the groups (p > 0.1, all comparisons). Patients who underwent endoscopic resection had shorter surgeries (320.3 ± 158.5 minutes vs. 495.3 ± 187.6 minutes (p = 0.0003), less intraoperative blood loss (282.2 ± 333.6 ml vs. 696.7 ± 500.2 ml (p < 0.0001), and shorter length of stay (3.5 ± 3.7 days vs. 8.8 ± 6.0 days (p < 0.0001). Additionally, patients treated endoscopically initiated adjuvant radiation treatment more quickly (48.0 ± 20.3 days vs. 72.0 ± 20.5 days (p = 0.01). CONCLUSIONS: An endoscopic endonasal approach facilitates a clinically meaningful improvement in surgical outcomes for skull base malignancies.


Asunto(s)
Neoplasias Nasales , Neoplasias de la Base del Cráneo , Endoscopía , Humanos , Cavidad Nasal/cirugía , Neoplasias Nasales/cirugía , Estudios Retrospectivos , Base del Cráneo/cirugía , Neoplasias de la Base del Cráneo/patología , Neoplasias de la Base del Cráneo/cirugía , Resultado del Tratamiento
17.
Entropy (Basel) ; 24(7)2022 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-35885140

RESUMEN

We study the collective motion of autonomous mobile agents in a ringlike environment. The agents' dynamics are inspired by known laboratory experiments on the dynamics of locust swarms. In these experiments, locusts placed at arbitrary locations and initial orientations on a ring-shaped arena are observed to eventually all march in the same direction. In this work we ask whether, and how fast, a similar phenomenon occurs in a stochastic swarm of simple locust-inspired agents. The agents are randomly initiated as marching either clockwise or counterclockwise on a discretized, wide ring-shaped region, which we subdivide into k concentric tracks of length n. Collisions cause agents to change their direction of motion. To avoid this, agents may decide to switch tracks to merge with platoons of agents marching in their direction. We prove that such agents must eventually converge to a local consensus about their direction of motion, meaning that all agents on each narrow track must eventually march in the same direction. We give asymptotic bounds for the expected time it takes for such convergence or "stabilization" to occur, which depends on the number of agents, the length of the tracks, and the number of tracks. We show that when agents also have a small probability of "erratic", random track-jumping behavior, a global consensus on the direction of motion across all tracks will eventually be reached. Finally, we verify our theoretical findings in numerical simulations.

18.
Glycobiology ; 31(7): 762-771, 2021 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-33554253

RESUMEN

Recombinant immunoglobulins (rIgGs) have become increasingly important as therapeutic agents and diagnostic tools in recent years. Genetic engineering allows the introduction of non-natural features such as the Sortase motif for site-directed labeling. In this study, the enzyme Sortase A (SrtA) was used for the proteolytic cleavage of rIgGs to produce their biotinylated Fab fragments by locating the cleavage site close to the hinge region. However, SrtA cleavage of engineered rabbit IgGs (rRb-IgGs) derived from human embryonic kidney (HEK) 293 cells showed significantly lower yields compared with their mouse counterparts. Nonrecombinant Rb-IgGs have N- and O-glycans, and the presence of O-glycans close to the hinge region of the rRb-IgGs might affect the susceptibility of these antibodies to SrtA cleavage. In addition, the glycosylation pattern of rIgGs differs depending on the host cell used for expression. Therefore, we analyzed the N- and O-glycans of various rRb-IgGs expressed in HEK293 cells, detecting and quantifying 13 different N-glycan and 3 different O-glycan structures. The distribution of the different detected glycoforms in our rRb-IgG N-glycan analysis is in agreement with previous studies on recombinant human IgG N-glycans, confirming the hypothesis that the host cell defines the glycosylation of the recombinant produced IgGs. O-glycosylation could be mapped onto the threonine residue within the hinge region sequence XPTCPPPX, as already described previously for nonrecombinant Rb-IgGs. Substitution of this threonine allowed an almost complete Fab fragment cleavage. Therefore, we could confirm the hypothesis that the O-glycans affect the SrtA activity, probably due to steric hindrance.


Asunto(s)
Inmunoglobulina G , Péptido Hidrolasas , Animales , Glicosilación , Células HEK293 , Humanos , Inmunoglobulina G/química , Ratones , Polisacáridos/química , Conejos
19.
Phys Rev Lett ; 127(16): 162001, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34723614

RESUMEN

Studying spin-momentum correlations in hadronic collisions offers a glimpse into a three-dimensional picture of proton structure. The transverse single-spin asymmetry for midrapidity isolated direct photons in p^{↑}+p collisions at sqrt[s]=200 GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). Because direct photons in particular are produced from the hard scattering and do not interact via the strong force, this measurement is a clean probe of initial-state spin-momentum correlations inside the proton and is in particular sensitive to gluon interference effects within the proton. This is the first time direct photons have been used as a probe of spin-momentum correlations at RHIC. The uncertainties on the results are a 50-fold improvement with respect to those of the one prior measurement for the same observable, from the Fermilab E704 experiment. These results constrain gluon spin-momentum correlations in transversely polarized protons.

20.
Chem Res Toxicol ; 34(9): 2032-2044, 2021 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-34427094

RESUMEN

Phosphine (PH3) is a highly toxic, corrosive, flammable, heavier-than-air gas that is a commonly used fumigant. When used as a fumigant, PH3 can be released from compressed gas tanks or produced from commercially available metal phosphide tablets. Although the mechanism of toxicity is unclear, PH3 is thought to be a metabolic poison. PH3 exposure induces multiorgan toxicity, and no effective antidotes or therapeutics have been identified. Current medical treatment consists largely of supportive care and maintenance of cardiovascular function. To better characterize the mechanism(s) driving PH3-induced toxicity, we have performed transcriptomic analysis on conscious adult male Sprague-Dawley rats following whole-body inhalation exposure to phosphine gas at various concentration-time products. PH3 exposure induced concentration- and time-dependent changes in gene expression across multiple tissues. These gene expression changes were mapped to pathophysiological responses using molecular pathway analysis. Toxicity pathways indicative of cardiac dysfunction, cardiac arteriopathy, and cardiac enlargement were identified. These cardiotoxic responses were linked to apelin-mediated cardiomyocyte and cardiac fibroblast signaling pathways. Evaluation of gene expression changes in blood revealed alterations in pathways associated with the uptake, transport, and utilization of iron. Altered erythropoietin signaling was also observed in the blood. Upstream regulator analysis identified several therapeutics predicted to counteract PH3-induced gene expression changes. These include antihypertensive drugs (losartan, candesartan, and prazosin) and therapeutics to reduce pathological cardiac remodeling (curcumin and TIMP3). This transcriptomics study has characterized molecular pathways involved in PH3-induced cardiotoxicity. These data will aid in elucidating a precise mechanism of toxicity for PH3 and guide the development of effective medical countermeasures for PH3-induced toxicity.


Asunto(s)
Plaguicidas/toxicidad , Fosfinas/toxicidad , Rodenticidas/toxicidad , Transcriptoma/efectos de los fármacos , Administración por Inhalación , Animales , Antihipertensivos/farmacología , Apelina/metabolismo , Cardiomegalia/inducido químicamente , Cardiotónicos/farmacología , Cardiotoxicidad/genética , Cardiotoxicidad/metabolismo , Corazón/efectos de los fármacos , Masculino , Fosfinas/administración & dosificación , Ratas Sprague-Dawley , Rodenticidas/administración & dosificación , Transducción de Señal/efectos de los fármacos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA