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1.
Cell ; 177(2): 315-325.e14, 2019 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-30929905

RESUMEN

Transmission of malaria parasites occurs when a female Anopheles mosquito feeds on an infected host to acquire nutrients for egg development. How parasites are affected by oogenetic processes, principally orchestrated by the steroid hormone 20-hydroxyecdysone (20E), remains largely unknown. Here we show that Plasmodium falciparum development is intimately but not competitively linked to processes shaping Anopheles gambiae reproduction. We unveil a 20E-mediated positive correlation between egg and oocyst numbers; impairing oogenesis by multiple 20E manipulations decreases parasite intensities. These manipulations, however, accelerate Plasmodium growth rates, allowing sporozoites to become infectious sooner. Parasites exploit mosquito lipids for faster growth, but they do so without further affecting egg development. These results suggest that P. falciparum has adopted a non-competitive evolutionary strategy of resource exploitation to optimize transmission while minimizing fitness costs to its mosquito vector. Our findings have profound implications for currently proposed control strategies aimed at suppressing mosquito populations.


Asunto(s)
Ecdisterona/metabolismo , Interacciones Huésped-Parásitos/fisiología , Malaria Falciparum/parasitología , Animales , Anopheles/parasitología , Culicidae , Ecdisterona/fisiología , Femenino , Células HEK293 , Humanos , Insectos Vectores , Malaria/parasitología , Ratones , Mosquitos Vectores , Células 3T3 NIH , Oogénesis/fisiología , Plasmodium/metabolismo , Plasmodium falciparum , Esporozoítos , Esteroides/metabolismo
2.
Proc Natl Acad Sci U S A ; 121(11): e2313842121, 2024 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-38437541

RESUMEN

Soil organic carbon (SOC) mineralization is a key component of the global carbon cycle. Its temperature sensitivity Q10 (which is defined as the factor of change in mineralization with a 10 °C temperature increase) is crucial for understanding the carbon cycle-climate change feedback but remains uncertain. Here, we demonstrate the universal control of carbon quality-availability tradeoffs on Q10. When carbon availability is not limited, Q10 is controlled by carbon quality; otherwise, substrate availability controls Q10. A model driven by such quality-availability tradeoffs explains 97% of the spatiotemporal variability of Q10 in incubations of soils across the globe and predicts a global Q10 of 2.1 ± 0.4 (mean ± one SD) with higher Q10 in northern high-latitude regions. We further reveal that global Q10 is predominantly governed by the mineralization of high-quality carbon. The work provides a foundation for predicting SOC dynamics under climate and land use changes which may alter soil carbon quality and availability.

3.
Proc Natl Acad Sci U S A ; 119(45): e2209382119, 2022 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-36603188

RESUMEN

Studies using rodent models have shown that relapse to drug or food seeking increases progressively during abstinence, a behavioral phenomenon termed "incubation of craving." Mechanistic studies of incubation of craving have focused on specific neurobiological targets within preselected brain areas. Recent methodological advances in whole-brain immunohistochemistry, clearing, and imaging now allow unbiased brain-wide cellular resolution mapping of regions and circuits engaged during learned behaviors. However, these whole-brain imaging approaches were developed for mouse brains, while incubation of drug craving has primarily been studied in rats, and incubation of food craving has not been demonstrated in mice. Here, we established a mouse model of incubation of palatable food craving and examined food reward seeking after 1, 15, and 60 abstinence days. We then used the neuronal activity marker Fos with intact-brain mapping procedures to identify corresponding patterns of brain-wide activation. Relapse to food seeking was significantly higher after 60 abstinence days than after 1 or 15 days. Using unbiased ClearMap analysis, we identified increased activation of multiple brain regions, particularly corticostriatal structures, following 60 but not 1 or 15 abstinence days. We used orthogonal SMART2 analysis to confirm these findings within corticostriatal and thalamocortical subvolumes and applied expert-guided registration to investigate subdivision and layer-specific activation patterns. Overall, we 1) identified brain-wide activity patterns during incubation of food seeking using complementary analytical approaches and 2) provide a single-cell resolution whole-brain atlas that can be used to identify functional networks and global architecture underlying the incubation of food craving.


Asunto(s)
Ansia , Metanfetamina , Animales , Ratones , Encéfalo , Ansia/fisiología , Señales (Psicología) , Comportamiento de Búsqueda de Drogas/fisiología , Alimentos , Recurrencia , Autoadministración
4.
Dev Dyn ; 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39166847

RESUMEN

BACKGROUND: Theory predicts that drought-resistant embryos with extended incubations are evolutionarily favored in environments with high mortality of larvae but safe for eggs. Here, we experimentally test, under common garden conditions, the effect of three incubation temperatures and media on embryonic developmental length, extended incubation out of the water, survival, metabolic rate, and hatching dynamics in the estuarine pupfish Garmanella pulchra. We also described the morphological changes of embryonic cortical structures related to air exposure. RESULTS: We found that embryos incubated out of water in low and medium temperatures present an extended incubation period beyond their hatching capability with a deep metabolic depression. Also, these embryos exhibited a hatching asynchrony not related to water availability. Embryos incubated at high temperatures did not show extended incubation, with decreased probability of survival out of water. Our morphological observations of the embryonic cortical structures reveal that the perivitelline space and hair-like filaments buffer the deleterious drought effects. CONCLUSIONS: Our results reveal that G. pulchra possesses life-history traits typical of two separate phenomena: delay hatching and diapause; supporting a true continuum between them, rather than a dichotomy. The evolution of these traits may respond to aerial exposure during low tides in the estuaries of Yucatán they inhabit.

5.
BMC Genomics ; 25(1): 309, 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38528494

RESUMEN

BACKGROUND: Incubation behaviour, an instinct for natural breeding in poultry, is strictly controlled by the central nervous system and multiple neuroendocrine hormones and neurotransmitters, and is closely associated with the cessation of egg laying. Therefore, it is essential for the commercial poultry industry to clarify the molecular regulation mechanism of incubation behaviour. Here, we used high-throughput sequencing technology to examine the pituitary transcriptome of Changshun green-shell laying hen, a local breed from Guizhou province, China, with strong broodiness, in two reproductive stages, including egg-laying phase (LP) and incubation phase (BP). We also analyze the differences in gene expression during the transition from egg-laying to incubation, and identify critical pathways and candidate genes involved in controlling the incubation behaviour in the pituitary. RESULTS: In this study, we demonstrated that a total of 2089 differently expressed genes (DEGs) were identified in the pituitary, including 842 up-regulated and 1247 down-regulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that steroid biosynthesis pathway and neuroactive ligand-receptor interaction were significantly enriched based on DEGs commonly identified in pituitary. Further analysis revealed that SRC, ITGB4, ITGB3, PIK3R3 and DRD2 may play crucial roles in the regulation of incubation behaviour. CONCLUSIONS: We identified 2089 DEGs and the key signaling pathways which may be closely correlated with incubation in Changshun green-shell laying hens, and clarified the molecular regulation mechanism of incubation behaviour. Our results indicate the complexity and variety of differences in reproductive behaviour of different chicken breeds.


Asunto(s)
Pollos , Transcriptoma , Animales , Femenino , Pollos/metabolismo , Perfilación de la Expresión Génica , Hipófisis/metabolismo , Hormonas/metabolismo
6.
Neurobiol Dis ; 190: 106363, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37996040

RESUMEN

Sporadic Creutzfeldt-Jakob disease (sCJD), the most common human prion disease, is thought to occur when the cellular prion protein (PrPC) spontaneously misfolds and assembles into prion fibrils, culminating in fatal neurodegeneration. In a genome-wide association study of sCJD, we recently identified risk variants in and around the gene STX6, with evidence to suggest a causal increase of STX6 expression in disease-relevant brain regions. STX6 encodes syntaxin-6, a SNARE protein primarily involved in early endosome to trans-Golgi network retrograde transport. Here we developed and characterised a mouse model with genetic depletion of Stx6 and investigated a causal role of Stx6 expression in mouse prion disease through a classical prion transmission study, assessing the impact of homozygous and heterozygous syntaxin-6 knockout on disease incubation periods and prion-related neuropathology. Following inoculation with RML prions, incubation periods in Stx6-/- and Stx6+/- mice differed by 12 days relative to wildtype. Similarly, in Stx6-/- mice, disease incubation periods following inoculation with ME7 prions also differed by 12 days. Histopathological analysis revealed a modest increase in astrogliosis in ME7-inoculated Stx6-/- animals and a variable effect of Stx6 expression on microglia activation, however no differences in neuronal loss, spongiform change or PrP deposition were observed at endpoint. Importantly, Stx6-/- mice are viable and fertile with no gross impairments on a range of neurological, biochemical, histological and skeletal structure tests. Our results provide some support for a pathological role of Stx6 expression in prion disease, which warrants further investigation in the context of prion disease but also other neurodegenerative diseases considering syntaxin-6 appears to have pleiotropic risk effects in progressive supranuclear palsy and Alzheimer's disease.


Asunto(s)
Síndrome de Creutzfeldt-Jakob , Enfermedades por Prión , Priones , Ratones , Humanos , Animales , Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/patología , Priones/genética , Priones/metabolismo , Estudio de Asociación del Genoma Completo , Ratones Transgénicos , Encéfalo/metabolismo , Enfermedades por Prión/genética , Enfermedades por Prión/patología , Proteínas Qa-SNARE/genética , Proteínas Qa-SNARE/metabolismo
7.
Emerg Infect Dis ; 30(6): 1173-1181, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38781950

RESUMEN

Understanding changes in the transmission dynamics of mpox requires comparing recent estimates of key epidemiologic parameters with historical data. We derived historical estimates for the incubation period and serial interval for mpox and contrasted them with pooled estimates from the 2022 outbreak. Our findings show the pooled mean infection-to-onset incubation period was 8.1 days for the 2022 outbreak and 8.2 days historically, indicating the incubation periods remained relatively consistent over time, despite a shift in the major mode of transmission. However, we estimated the onset-to-onset serial interval at 8.7 days using 2022 data, compared with 14.2 days using historical data. Although the reason for this shortening of the serial interval is unclear, it may be because of increased public health interventions or a shift in the mode of transmission. Recognizing such temporal shifts is essential for informed response strategies, and public health measures remain crucial for controlling mpox and similar future outbreaks.


Asunto(s)
Brotes de Enfermedades , Periodo de Incubación de Enfermedades Infecciosas , Mpox , Humanos , Mpox/epidemiología , Mpox/historia , Mpox/transmisión , Mpox/virología , Historia del Siglo XXI , Salud Global
8.
Emerg Infect Dis ; 30(1): 180-182, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38063085

RESUMEN

We estimated the incubation period for mpox during an outbreak in Pereira, Colombia, using data from 11 confirmed cases. Mean incubation period was 7.1 (95% CI 4.9-9.9) days, consistent with previous outbreaks. Accurately estimating the incubation period provides insights into transmission dynamics, informing public health interventions and surveillance strategies.


Asunto(s)
Mpox , Masculino , Humanos , Colombia/epidemiología , Periodo de Incubación de Enfermedades Infecciosas , Brotes de Enfermedades , Salud Pública , Homosexualidad Masculina
9.
Emerg Infect Dis ; 30(10)2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39255234

RESUMEN

We used published data from outbreak investigations of monkeypox virus clade I in the Democratic Republic of the Congo to estimate the distributions of critical epidemiological parameters. We estimated a mean incubation period of 9.9 days (95% credible interval [CrI] 8.5-11.5 days) and a mean generation time of 17.2 days (95% CrI 14.1-20.9 days) or 11.3 days (95% CrI 9.4-14.0 days), depending on the considered dataset. Presymptomatic transmission was limited. Those estimates suggest generally slower transmission dynamics in clade I than in clade IIb. The time-varying reproduction number for clade I in the Democratic Republic of the Congo was estimated to be below the epidemic threshold in the first half of 2024. However, in the South Kivu Province, where the newly identified subclade Ib has been associated with sustained human-to-human transmission, we estimated an effective reproduction number above the epidemic threshold (95% CrI 0.96-1.27).

10.
Am J Epidemiol ; 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38988237

RESUMEN

The incubation period is of paramount importance in infectious disease epidemiology as it informs about the transmission potential of a pathogenic organism and helps to plan public health strategies to keep an epidemic outbreak under control. Estimation of the incubation period distribution from reported exposure times and symptom onset times is challenging as the underlying data is coarse. We develop a new Bayesian methodology using Laplacian-P-splines that provides a semi-parametric estimation of the incubation density based on a Langevinized Gibbs sampler. A finite mixture density smoother informs a set of parametric distributions via moment matching and an information criterion arbitrates between competing candidates. Algorithms underlying our method find a natural nest within the EpiLPS package, which has been extended to cover estimation of incubation times. Various simulation scenarios accounting for different levels of data coarseness are considered with encouraging results. Applications to real data on COVID-19, MERS and Mpox reveal results that are in alignment with what has been obtained in recent studies. The proposed flexible approach is an interesting alternative to classic Bayesian parametric methods for estimation of the incubation distribution.

11.
Am Nat ; 203(2): 254-266, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-38306278

RESUMEN

AbstractDespite avid interest in life history trade-offs and the costs of reproduction, evidence that increased parental allocation reduces subsequent breeding productivity is mixed. This uncertainty may be attributable to environmental heterogeneity in space and time, necessitating experiments across a range of ecological contexts. Over three breeding seasons, we cross-fostered clutches between nests to manipulate incubation duration in a wild population of Carolina wrens, a species in which only females incubate, to test for a cost of incubation on current and future reproduction. Prolonged incubation affected maternal productivity in a manner dependent on the current environment and initial investment in eggs, suggesting that incubation is optimized according to other components of reproduction and individual quality. Effects of incubation duration on foster nestling condition varied between years, being costly in one, beneficial in another, and neutral in the third. The proportion of young fledged, females' probability of breeding again within seasons, and subsequent clutch sizes all declined with increasing incubation effort-effects that became more pronounced as seasons progressed. Therefore, costs of incubation were almost entirely dependent on maternal quality and environmental variation, illustrating the importance of conducting experiments across a range of environmental settings for understanding the costs of reproduction and evolution of life histories.


Asunto(s)
Pájaros Cantores , Animales , Femenino , Reproducción , Probabilidad , Estaciones del Año , Incertidumbre
12.
Am Nat ; 203(2): 267-283, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-38306283

RESUMEN

AbstractVocal production learning (the capacity to learn to produce vocalizations) is a multidimensional trait that involves different learning mechanisms during different temporal and socioecological contexts. Key outstanding questions are whether vocal production learning begins during the embryonic stage and whether mothers play an active role in this through pupil-directed vocalization behaviors. We examined variation in vocal copy similarity (an indicator of learning) in eight species from the songbird family Maluridae, using comparative and experimental approaches. We found that (1) incubating females from all species vocalized inside the nest and produced call types including a signature "B element" that was structurally similar to their nestlings' begging call; (2) in a prenatal playback experiment using superb fairy wrens (Malurus cyaneus), embryos showed a stronger heart rate response to playbacks of the B element than to another call element (A); and (3) mothers that produced slower calls had offspring with greater similarity between their begging call and the mother's B element vocalization. We conclude that malurid mothers display behaviors concordant with pupil-directed vocalizations and may actively influence their offspring's early life through sound learning shaped by maternal call tempo.


Asunto(s)
Passeriformes , Pájaros Cantores , Animales , Femenino , Humanos , Madres , Vocalización Animal/fisiología , Pájaros Cantores/fisiología , Aprendizaje
13.
Proc Biol Sci ; 291(2025): 20240083, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38917866

RESUMEN

Externally laid eggs are often responsive to environmental cues; however, it is unclear how such plasticity evolves. In Trinidad, the killifish (Anablepsoides hartii) is found in communities with and without predators. Here, killifish inhabit shallower, ephemeral habitats in sites with predators. Such shifts may increase the exposure of eggs to air and lead to possible desiccation. We compared egg-hatching plasticity between communities by rearing eggs terrestrially on peat moss or in water. The timing of hatching did not differ between communities when eggs were reared in water. Eggs from sites with predators responded to terrestrial incubation by hatching significantly earlier compared with water-reared eggs. These responses were weaker in sites with no predators. Such divergent trends show that the presence of predators is associated with evolutionary shifts in hatching plasticity. Our results provide evidence for local adaptation in embryonic plasticity at the population scale.


Asunto(s)
Evolución Biológica , Fundulidae , Animales , Fundulidae/fisiología , Fundulidae/embriología , Trinidad y Tobago , Ecosistema , Óvulo/fisiología , Adaptación Fisiológica , Conducta Predatoria , Peces Killi
14.
Proc Biol Sci ; 291(2017): 20232264, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38378147

RESUMEN

Complex incubation strategies have evolved to solve the trade-off between parent survival and care for their eggs with often brief departures (recesses) that maximize egg survival, and infrequent extended recesses maximizing adult condition. Here we examined incubation behaviour of sanderlings (Calidris alba), a species that exhibits both biparental and uniparental incubation behaviour. During 11 breeding seasons in Greenland, we have quantified incubation variability with thermologgers placed in nests. We estimated the impact of environmental conditions and individual characteristics on the occurrence and the duration of recesses. We found that extended recesses are a unique feature of uniparentals, and their frequency and duration increased in colder temperatures. The relationship was mediated by body condition, with individuals in poor condition performing longer extended recesses in colder temperatures. This suggests that extended recesses may represent a shift towards self-maintenance at the expense of the egg care, allowing birds to continue incubating under unfavourable conditions. Our study illustrates how extended recesses may be a key breeding strategy to overcome high energetic costs associated with incubation. Quantifying such behavioural flexibility paves the way for tracking future behavioural responses of individuals in the face of changing environments.


Asunto(s)
Charadriiformes , Humanos , Animales , Temperatura , Aves/fisiología , Frío , Cruzamiento
15.
Appl Environ Microbiol ; 90(8): e0091524, 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-38984844

RESUMEN

Humans and animals encounter a summation of exposures during their lifetime (the exposome). In recent years, the scope of the exposome has begun to include microplastics. Microplastics (MPs) have increasingly been found in locations, including in animal gastrointestinal tracts, where there could be an interaction with Salmonella enterica serovar Typhimurium, one of the commonly isolated serovars from processed chicken. However, there is limited knowledge on how gut microbiomes are affected by microplastics and if an effect would be exacerbated by the presence of a pathogen. In this study, we aimed to determine if acute exposure to microplastics in vitro altered the gut microbiome membership and activity. The microbiota response to a 24 h co-exposure to Salmonella enterica serovar Typhimurium and/or low-density polyethylene (PE) microplastics in an in vitro broiler cecal model was determined using 16S rRNA amplicon sequencing (Illumina) and untargeted metabolomics. Community sequencing results indicated that PE fiber with and without S. Typhimurium yielded a lower Firmicutes/Bacteroides ratio compared with other treatment groups, which is associated with poor gut health, and overall had greater changes to the cecal microbial community composition. However, changes in the total metabolome were primarily driven by the presence of S. Typhimurium. Additionally, the co-exposure to PE fiber and S. Typhimurium caused greater cecal microbial community and metabolome changes than either exposure alone. Our results indicate that polymer shape is an important factor in effects resulting from exposure. It also demonstrates that microplastic-pathogen interactions cause metabolic alterations to the chicken cecal microbiome in an in vitro chicken cecal mesocosm. IMPORTANCE: Researching the exposome, a summation of exposure to one's lifespan, will aid in determining the environmental factors that contribute to disease states. There is an emerging concern that microplastic-pathogen interactions in the gastrointestinal tract of broiler chickens may lead to an increase in Salmonella infection across flocks and eventually increased incidence of human salmonellosis cases. In this research article, we elucidated the effects of acute co-exposure to polyethylene microplastics and Salmonella enterica serovar Typhimurium on the ceca microbial community in vitro. Salmonella presence caused strong shifts in the cecal metabolome but not the microbiome. The inverse was true for polyethylene fiber. Polyethylene powder had almost no effect. The co-exposure had worse effects than either alone. This demonstrates that exposure effects to the gut microbial community are contaminant-specific. When combined, the interactions between exposures exacerbate changes to the gut environment, necessitating future experiments studying low-dose chronic exposure effects with in vivo model systems.


Asunto(s)
Ciego , Pollos , Microbioma Gastrointestinal , Metaboloma , Polietileno , Salmonella typhimurium , Animales , Pollos/microbiología , Ciego/microbiología , Microbioma Gastrointestinal/efectos de los fármacos , Salmonella typhimurium/efectos de los fármacos , Polietileno/metabolismo , Metaboloma/efectos de los fármacos , Microplásticos , ARN Ribosómico 16S/genética , Salmonelosis Animal/microbiología
16.
Front Zool ; 21(1): 12, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38632631

RESUMEN

BACKGROUND: Energy and time allocation in seabirds differ between consecutive stages of breeding given various requirements of particular phases of the reproductive period. Theses allocations may also be sex-specific considering differential energetic or nutritional requirements of males and females and/or sexual segregation in foraging niches and/or areas. In this study we investigated the foraging ecology of an Arctic, zooplanktivorous seabird, the little auk Alle alle during the pre-laying period using remote sensing of the environment and GPS-TDR loggers deployed on birds. We compared foraging trips range and habitats of birds with other stages of the breeding period and between sexes. RESULTS: We found that little auks during the pre-laying period foraged exclusively in cold sea surface temperature zones (with temperatures < 5 ºC) but in various sea depth zones. They dived to similar depths ranging from -4.0 to -10.9 m, exploring various thermal microhabitats (with mean temperatures values ranging from 2.2 °C in Shelf sea depth zone to 5.9 °C in Deep sea depth zone). The majority of foraging trips and dives characteristics were similar to subsequent phases of breeding. However, home ranges during the pre-laying trips were wider compared to the incubation period. As expected, females exhibited wider foraging niches compared to males (wider range of sea surface temperature and sea depth in foraging locations), which could be explained by sex specific energetic and/or nutritional requirements (females producing an egg). We also delineated local foraging areas important for little auks during their whole breeding season. Protection of these areas is crucial for sustaining the local marine biodiversity. CONCLUSIONS: We found that little auks females during the pre-laying period explored wider foraging niches compared to males. These differences may be attributed to sex-specific nutritional or/and energetical constraints at this stage of breeding. The results of this study also emphasize the importance of shelf Arctic-type water masses as the foraging areas for little auks during successive stages of breeding.

17.
J Exp Biol ; 227(3)2024 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-38230426

RESUMEN

Telomeres, the repetitive DNA regions that protect the ends of chromosomes, and their shortening have been linked to key life history trade-offs among growth, reproduction and lifespan. In contrast to most endotherms, many ectotherms can compensate for telomere shortening throughout life by upregulation of telomerase in somatic tissues. However, during development, marked by rapid growth and an increased sensitivity to extrinsic factors, the upregulation of telomerase may be overwhelmed, resulting in long-term impacts on telomere dynamics. In ectotherms, one extrinsic factor that may play a particularly important role in development is temperature. Here, we investigated the influence of developmental temperature and sex on early-life telomere dynamics in an oviparous ectotherm, Lacerta agilis. While there was no effect of developmental temperature on telomere length at hatching, there were subsequent effects on telomere maintenance capacity, with individuals incubated at warm temperatures exhibiting less telomere maintenance compared with cool-incubated individuals. Telomere dynamics were also sexually dimorphic, with females having longer telomeres and greater telomere maintenance compared with males. We suggest that selection drives this sexual dimorphism in telomere maintenance, in which females maximise their lifetime reproductive success by investing in traits promoting longevity such as maintenance, while males invest in short-term reproductive gains through a polygynous mating behaviour. These early-life effects, therefore, have the potential to mediate life-long changes to life histories.


Asunto(s)
Lagartos , Telomerasa , Humanos , Animales , Masculino , Femenino , Telomerasa/genética , Longevidad/genética , Acortamiento del Telómero , Lagartos/metabolismo , Telómero/genética , Telómero/metabolismo , Homeostasis del Telómero
18.
BMC Infect Dis ; 24(1): 555, 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38831419

RESUMEN

BACKGROUND: Estimation of the SARS-CoV-2 incubation time distribution is hampered by incomplete data about infection. We discuss two biases that may result from incorrect handling of such data. Notified cases may recall recent exposures more precisely (differential recall). This creates bias if the analysis is restricted to observations with well-defined exposures, as longer incubation times are more likely to be excluded. Another bias occurred in the initial estimates based on data concerning travellers from Wuhan. Only individuals who developed symptoms after their departure were included, leading to under-representation of cases with shorter incubation times (left truncation). This issue was not addressed in the analyses performed in the literature. METHODS: We performed simulations and provide a literature review to investigate the amount of bias in estimated percentiles of the SARS-CoV-2 incubation time distribution. RESULTS: Depending on the rate of differential recall, restricting the analysis to a subset of narrow exposure windows resulted in underestimation in the median and even more in the 95th percentile. Failing to account for left truncation led to an overestimation of multiple days in both the median and the 95th percentile. CONCLUSION: We examined two overlooked sources of bias concerning exposure information that the researcher engaged in incubation time estimation needs to be aware of.


Asunto(s)
Sesgo , COVID-19 , Periodo de Incubación de Enfermedades Infecciosas , SARS-CoV-2 , Humanos , COVID-19/epidemiología , Simulación por Computador
19.
BMC Infect Dis ; 24(1): 294, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38448822

RESUMEN

BACKGROUND: The latent and incubation periods characterize the transmission of infectious viruses and are the basis for the development of outbreak prevention and control strategies. However, systematic studies on the latent period and associated factors with the incubation period for SAS-CoV-2 variants are still lacking. We inferred the two durations of Delta, BA.1, and BA.2 cases and analyzed the associated factors. METHODS: The Delta, BA.1, and BA.2 (and its lineages BA.2.2 and BA.2.76) cases with clear transmission chains and infectors from 10 local SAS-CoV-2 epidemics in China were enrolled. The latent and incubation periods were fitted by the Gamma distribution, and associated factors were analyzed using the accelerated failure time model. RESULTS: The mean latent period for 672 Delta, 208 BA.1, and 677 BA.2 cases was 4.40 (95%CI: 4.24 ~ 4.63), 2.50 (95%CI: 2.27 ~ 2.76), and 2.58 (95%CI: 2.48 ~ 2.69) days, respectively, with 85.65% (95%CI: 83.40 ~ 87.77%), 97.80% (95%CI: 96.35 ~ 98.89%), and 98.87% (95%CI: 98.40 ~ 99.27%) of them starting to shed viruses within 7 days after exposure. In 405 Delta, 75 BA.1, and 345 BA.2 symptomatic cases, the mean latent period was 0.76, 1.07, and 0.79 days shorter than the mean incubation period [5.04 (95%CI: 4.83 ~ 5.33), 3.42 (95%CI: 3.00 ~ 3.89), and 3.39 (95%CI: 3.24 ~ 3.55) days], respectively. No significant difference was observed in the two durations between BA.1 and BA.2 cases. After controlling for the sex, clinical severity, vaccination history, number of infectors, the length of exposure window and shedding window, the latent period [Delta: exp(ß) = 0.81, 95%CI: 0.66 ~ 0.98, p = 0.034; Omicron: exp(ß) = 0.82, 95%CI: 0.71 ~ 0.94, p = 0.004] and incubation period [Delta: exp(ß) = 0.69, 95%CI: 0.55 ~ 0.86, p < 0.001; Omicron: exp(ß) = 0.83, 95%CI: 0.72 ~ 0.96, p = 0.013] were significantly shorter in 18 ~ 49 years but did not change significantly in ≥ 50 years compared with 0 ~ 17 years. CONCLUSION: Pre-symptomatic transmission can occur in Delta, BA.1, and BA.2 cases. The latent and incubation periods between BA.1 and BA.2 were similar but shorter compared with Delta. Age may be associated with the latent and incubation periods of SARS-CoV-2.


Asunto(s)
Epidemias , Periodo de Incubación de Enfermedades Infecciosas , Humanos , Estudios Transversales , China/epidemiología , Brotes de Enfermedades
20.
Anal Bioanal Chem ; 416(10): 2541-2551, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38451277

RESUMEN

In this study, an online electrochemistry coupling high-performance liquid chromatography-mass spectrometry (EC-HPLC-MS) technology has been developed for simulating metabolic reactions and rapid analysis of metabolites of flavone, quercetin, and rutin, which are not only widely present compounds with pharmacological activity in nature, but also have structural similarity and variability. The simulated metabolic processes of the substrates (phase I and phase II metabolism) were implemented on the surface of glassy carbon electrode (GCE) by using different electrochemical methods. After online chromatographic separation, the products were transmitted to a mass spectrometer for detection, in order to speculate relevant reaction pathways and structural information of the reaction product. The main metabolites, including methylation, hydroxylation, hydrolysis, and conjugation reaction products, had been successfully identified through the designed in situ hyphenated technique. Furthermore, compared with metabolites produced by in vitro incubation of rat liver microsomes, it was found that the products of electrochemical simulated metabolism were more abundant with diverse metabolic pathways. The results indicated that the proposed method exhibited advantages in the sample pretreatment process and detection cycle without compromising the reliability and accuracy of the results.


Asunto(s)
Flavonoides , Cromatografía Líquida con Espectrometría de Masas , Animales , Ratas , Cromatografía Líquida de Alta Presión/métodos , Electroquímica , Flavonoides/metabolismo , Microsomas Hepáticos/metabolismo , Oxidación-Reducción , Reproducibilidad de los Resultados
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