Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
1.
Gen Comp Endocrinol ; 340: 114324, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37247825

RESUMO

Pubertal stress causes enduring sexual behavior dysfunction in males and females, but the underlying mechanism remains unknown. These changes may arise from pubertal programming of the hypothalamic-pituitary-gonadal axis. Previous findings show that stress exposure downregulates the hypothalamic-pituitary-gonadal axis, particularly through the reduction of the neuropeptide kisspeptin (Kiss1) and its receptor (Kiss1R). Although acute changes in kiss1 and Kiss1r genes have been observed following pubertal immune stress, it is unclear whether immune stress-induced downregulation of kiss1 and kiss1r persists beyond puberty. The current study investigated the enduring sex-specific consequences of lipopolysaccharide on the expression of Kiss1 and Kiss1r in 160 pubertal or adult mice at multiple time points. Six-week and 10-week-old male and female mice were treated with either saline or with lipopolysaccharide. Mice were euthanized either 8 h or 4 weeks following treatment. Although we did not identify any sex differences, our results revealed that lipopolysaccharide treatment decreases hypothalamic Kiss1 and Kiss1r in both pubertal and adult mice within 8 h of treatment. The decreased hypothalamic Kiss1 expression persists 4 weeks later only in mice treated with lipopolysaccharide during puberty. Our findings highlight the age-dependent vulnerability of the hypothalamic-pituitary-gonadal axis to immune stress, providing a better understanding of the mechanisms implicated in allostatic shift during immune stress. Finally, our findings also show the effects of immune stress on various components of the hypothalamic-pituitary-gonadal axis, which could have implications for sexual and fertility-related dysfunctions.


Assuntos
Kisspeptinas , Lipopolissacarídeos , Camundongos , Animais , Feminino , Masculino , Kisspeptinas/genética , Receptores de Kisspeptina-1/genética , Lipopolissacarídeos/toxicidade , Eixo Hipotalâmico-Hipofisário-Gonadal , Maturidade Sexual/genética
2.
Ecol Lett ; 25(11): 2435-2447, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36197736

RESUMO

Trophic transfer of energy through marine food webs is strongly influenced by prey aggregation and its exploitation by predators. Rapid aggregation of some marine fish and crustacean forage species during wind-driven coastal upwelling has recently been discovered, motivating the hypothesis that predators of these forage species track the upwelling circulation in which prey aggregation occurs. We examine this hypothesis in the central California Current Ecosystem using integrative observations of upwelling dynamics, forage species' aggregation, and blue whale movement. Directional origins of blue whale calls repeatedly tracked upwelling plume circulation when wind-driven upwelling intensified and aggregation of forage species was heightened. Our findings illustrate a resource tracking strategy by which blue whales may maximize energy gain amid ephemeral foraging opportunities. These findings have implications for the ecology and conservation of diverse predators that are sustained by forage populations whose behaviour is responsive to episodic environmental dynamics.


Assuntos
Balaenoptera , Animais , Ecossistema , Vento , Oceanos e Mares , Cadeia Alimentar , Comportamento Predatório
3.
J Acoust Soc Am ; 151(4): 2507, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35461507

RESUMO

From February 2019 through January 2021, data were collected by an acoustic vector sensor moored on the seafloor at a depth of approximately 900 m just outside of Monterey Bay, California, near a major shipping lane off the California coast. Analysis of the vector sensor data has shown the ability to accurately determine bearings to merchant vessels at ranges up to 60 km. This paper examines the features of the low-frequency soundscape using spectral probability densities and evaluates directional features through vector intensity processing as well as coherent linear and adaptive processing of the vector sensor channels. Merchant vessel acoustic data were analyzed using the 1/3 octave band centered at 63 Hz. Over the period analyzed, a reduction in merchant vessel noise was observed between February and June 2020 relative to the same period in 2019, consistent with a reduction in vessel traffic due to the worldwide response to COVID-19. The directional features of the data evaluated through adaptive processing methods also suggest this reduction can be most clearly distinguished towards the south, where the shipping lane is limited to transiting vessels, rather to the north-northwest, where merchant vessels tend to congregate on approach into the San Francisco Bay area.

4.
Cladistics ; 36(4): 348-357, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-34618971

RESUMO

Antimicrobial resistance (AMR) in pathogenic strains of bacteria, such as Escherichia coli (E. coli), adversely impacts personal and public health. In this study, we examine competing hypotheses for the evolution of AMR including (i) 'genetic capitalism' in which genotypes that confer antibiotic resistance are gained and not often lost in lineages, and (ii) 'stabilizing selection' in which genotypes that confer antibiotic resistance are gained and lost often. To test these hypotheses, we assembled a dataset that includes annotations for 409 AMR genotypes and a phylogenetic tree based on genome-wide single nucleotide polymorphisms from 29 255 isolates of E. coli collected over the past 134 years. We used phylogenetic methods to count the times each AMR genotype was gained and lost across the tree and used model-based clustering of the genotypes with respect to their gain and loss rates. We demonstrate that many genotypes cluster to support the hypothesis for genetic capitalism while a few genotypes cluster to support the hypothesis for stabilizing selection. Comparing the sets of genotypes that fall under each of the hypotheses, we found a statistically significant difference in the breakdown of resistance mechanisms through which the AMR genotypes function. The result that many AMR genotypes cluster under genetic capitalism reflects that strong positive selective forces, primarily induced by human industrialization of antibiotics, outweigh the potential fitness costs to the bacterial lineages for carrying the AMR genotypes. We expect genetic capitalism to further drive bacterial lineages to resist antibiotics. We find that antibiotics that function via replacement and efflux tend to behave under stabilizing selection and thus may be valuable in an antibiotic cycling strategy.


Assuntos
Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Análise por Conglomerados , Genótipo , Filogenia , Polimorfismo de Nucleotídeo Único , Shigella/genética
5.
Isr J Chem ; 60(3-4): 394-397, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33859442

RESUMO

A method for the regioselective 1,2-arylboration of 1,3-butadiene, a feedstock chemical, is reported. The reactions result in the formation of products that can be easily elaborated to other structures. The mechanistic details of this process are also discussed.

6.
Brain Behav Immun ; 81: 198-212, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31212008

RESUMO

Puberty/adolescence is a significant period of development and a time with a high emergence of psychiatric disorders. During this period, there is increased neuroplasticity and heightened vulnerability to stress and inflammation. The gut microbiome regulates stress and inflammatory responses and can alter brain chemistry and behaviour. However, the role of the gut microbiota during pubertal development remains largely uninvestigated. The current study examined gut manipulation with probiotics during puberty in CD1 mice on lipopolysaccharide (LPS)-induced immune responses and enduring effects on anxiety- and depression-like behaviours and stress-reactivity in adulthood. Probiotics reduced LPS-induced sickness behaviour at 12 h in females and at 48 h following LPS treatment in males. Probiotics also reduced LPS-induced changes in body weight at 48 h post-treatment in females. Probiotic treatment also prevented LPS-induced increases in pro- and anti-inflammatory peripheral cytokines at 8 h following LPS treatment, reduced central cytokine mRNA expression in the hypothalamus, hippocampus and PFC, and prevented LPS-induced changes to in the gut microbiota. A single exposure to LPS during puberty resulted in enduring depression-like behaviour in female mice, and anxiety-like behaviour in male mice in adulthood. However, pubertal exposure to probiotics prevented enduring LPS-induced depression-like behaviour in females and anxiety-like behaviors in males. Moreover, probiotics altered toll-like receptor-4 activity in the paraventricular nucleus of the hypothalamus (PVN) in males in response to a novel stressor in adulthood. Our results suggest that the gut microbiome plays an important role in pubertal neurodevelopment. These findings indicate that exposure to probiotics during puberty mitigates inflammation and decreases stress-induced vulnerabilities to emotional behaviours later in life, in a sex-specific manner.


Assuntos
Microbioma Gastrointestinal/fisiologia , Probióticos/farmacologia , Maturidade Sexual/efeitos dos fármacos , Animais , Ansiedade/tratamento farmacológico , Ansiedade/metabolismo , Transtornos de Ansiedade/tratamento farmacológico , Transtornos de Ansiedade/metabolismo , Comportamento Animal/fisiologia , Citocinas/metabolismo , Depressão/tratamento farmacológico , Depressão/metabolismo , Transtorno Depressivo/tratamento farmacológico , Transtorno Depressivo/metabolismo , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Comportamento de Doença/efeitos dos fármacos , Inflamação/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Fatores Sexuais
7.
J Acoust Soc Am ; 146(3): 1875, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31590552

RESUMO

The three-dimensional Monterey-Miami parabolic equation model is used to simulate a nonlinear internal wave (NIW) crossing the sound field in a shallow water environment. The impetus for this research stems from acoustic measurements taken during the Shallow Water '06 (SW06) field experiment, where a NIW traversed the water column such that soliton wavecrests were nearly parallel to the source-receiver path. Horizontal refraction effects are important in this scenario. A sound speed profile adapted from experimental SW06 data is used to simulate the NIW, assuming variations along the wavecrests (e.g., curvature) are negligible. Broadband and modal energy metrics show acoustic fluctuations due to internal wave activity. Repeated model runs simulate the NIW crossing the parabolic equation (PE) field over space and time. Statistical analysis shows the PE data are best fit by a lognormal distribution but tends to an exponential distribution during certain scenarios. Small angle differences between the acoustic track and the propagating NIW cause substantial differences in energy distribution throughout the PE field. While refraction effects due to the leading edge of the NIW's arrival are important in all cases, the impacts of focusing and defocusing in the perfectly parallel case dominate the field fluctuations. In the non-parallel case, the strong fluctuations introduced by the passage of the NIW are of similar order to the refraction off the leading edge.

8.
Angew Chem Int Ed Engl ; 58(6): 1719-1723, 2019 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-30521697

RESUMO

Two methods are reported for the 1,2- and 1,1-arylboration of α-methyl vinyl arenes. In the case of 1,2-arylboration, the formation of a quaternary center occurred through a rare cross-coupling reaction of a tertiary organometallic complex. 1,1-Arylboration was enabled by catalyst optimization and occurred through a ß-hydride elimination/reinsertion cascade. Enantioselective variants of both processes are presented as well as mechanistic investigations.


Assuntos
Alcenos/química , Compostos de Boro/síntese química , Cobre/química , Paládio/química , Compostos de Boro/química , Catálise , Estrutura Molecular
9.
Angew Chem Int Ed Engl ; 57(21): 6146-6149, 2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29697174

RESUMO

A method for the heteroarylboration of 1,3-dienes is presented. The process involves an unusual cine substitution of 3-bromopyridine derivatives to deliver highly functionalized heterocyclic products. Mechanistic studies are included that clarify the details of this unusual process.


Assuntos
Alcadienos/química , Compostos de Boro/síntese química , Cobre/química , Piridinas/química , Compostos de Boro/química , Catálise , Estrutura Molecular
10.
J Am Chem Soc ; 139(23): 7721-7724, 2017 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-28581713

RESUMO

A method for the regioselective arylboration of isoprene and its derivatives is presented. These reactions allow for the synthesis of useful building blocks from simple components. Through these studies, an unusual additive effect with DMAP has been uncovered that allows for altered reactivity and the formation of quaternary carbon centers. The utility of this method is demonstrated toward the formal synthesis of mesembrine.

11.
J Acoust Soc Am ; 142(2): 523, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28863613

RESUMO

The reciprocity equation commonly stated in underwater acoustics relates pressure fields and monopole sources. It is often used to predict the pressure measured by a hydrophone for multiple source locations by placing a source at the hydrophone location and calculating the field everywhere for that source. A similar equation that governs the orthogonal components of the particle velocity field is needed to enable this computational method to be used for acoustic vector sensors. This paper derives a general reciprocity equation that accounts for both monopole and dipole sources. This vector-scalar reciprocity equation can be used to calculate individual components of the received vector field by altering the source type used in the propagation calculation. This enables a propagation model to calculate the received vector field components for an arbitrary number of source locations with a single model run for each vector field component instead of requiring one model run for each source location. Application of the vector-scalar reciprocity principle is demonstrated with analytic solutions for a range-independent environment and with numerical solutions for a range-dependent environment using a parabolic equation model.

12.
Angew Chem Int Ed Engl ; 56(43): 13314-13318, 2017 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-28849603

RESUMO

A method for the copper-catalyzed borylacylation of activated alkenes is presented. The reaction involves borylcupration of the alkene, followed by capture of the generated alkyl-copper intermediate with an acid chloride. The reactions operated with low catalyst loading and generally occurre within 15 min at room temperature for a range of activated alkenes. In the case of vinyl arenes, enantioselective borylacylation was possible.


Assuntos
Alcenos/química , Cloretos/química , Cobre/química , Acilação , Benzoatos/química , Compostos de Boro/química , Catálise , Cristalografia por Raios X , Conformação Molecular
13.
Behav Brain Sci ; 38: e145, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26786407

RESUMO

Duarte et al. are correct that the social science enterprise would improve on several fronts if the number of politically conservative researchers were to increase; however, because they misunderstand the degree to which liberals and conservatives are dispositionally different, they fail to appreciate the full range of reasons that conservatives are reluctant to enter the modern social sciences.


Assuntos
Emoções , Política , Humanos , Personalidade , Pesquisadores , Ciências Sociais
14.
Angew Chem Int Ed Engl ; 54(17): 5228-31, 2015 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-25727074

RESUMO

A method for the diastereoselective carboboration of 1,2-disubstituted styrenes with aryl/vinyl bromides and (Bpin)2 is reported. High diastereoselectivities and yields are observed for the formation of either diastereomer of the product from a single alkene isomer. These reactions provide access to a diverse range of structures from simple starting materials.

15.
Chemistry ; 20(38): 12032-6, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25113669

RESUMO

A synergistic Pd/Cu system for the coupling of alkenes, (Bpin)2 (pin = pinacolate), and aryl/vinyl bromides is disclosed. This method allows for the catalytic generation of secondary Csp(3)-Cu nucleophiles in situ and subsequent Pd-catalyzed cross-coupling.

16.
Behav Brain Sci ; 37(3): 333-50, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25101362

RESUMO

A broad, multidisciplinary empirical literature reports that individual-level differences in psychology and biology map onto variation in political orientation. In our target article we argued that negativity bias can explain a surprisingly large share of these findings. The commentators generally support the negativity bias hypothesis but suggest theoretical and empirical revisions and refinements. In this response, we organize these proposals, suggestions, and criticisms into four thematic categories and assess their potential for furthering theories and empirical investigations of the bases for individual-variation in political ideology.


Assuntos
Atitude , Individualidade , Modelos Psicológicos , Personalidade/fisiologia , Política , Humanos
17.
Behav Brain Sci ; 37(3): 297-307, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24970428

RESUMO

Disputes between those holding differing political views are ubiquitous and deep-seated, and they often follow common, recognizable lines. The supporters of tradition and stability, sometimes referred to as conservatives, do battle with the supporters of innovation and reform, sometimes referred to as liberals. Understanding the correlates of those distinct political orientations is probably a prerequisite for managing political disputes, which are a source of social conflict that can lead to frustration and even bloodshed. A rapidly growing body of empirical evidence documents a multitude of ways in which liberals and conservatives differ from each other in purviews of life with little direct connection to politics, from tastes in art to desire for closure and from disgust sensitivity to the tendency to pursue new information, but the central theme of the differences is a matter of debate. In this article, we argue that one organizing element of the many differences between liberals and conservatives is the nature of their physiological and psychological responses to features of the environment that are negative. Compared with liberals, conservatives tend to register greater physiological responses to such stimuli and also to devote more psychological resources to them. Operating from this point of departure, we suggest approaches for refining understanding of the broad relationship between political views and response to the negative. We conclude with a discussion of normative implications, stressing that identifying differences across ideological groups is not tantamount to declaring one ideology superior to another.


Assuntos
Atitude , Individualidade , Modelos Psicológicos , Personalidade/fisiologia , Política , Humanos
18.
Angew Chem Int Ed Engl ; 53(13): 3475-9, 2014 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-24677502

RESUMO

Copper-catalyzed Suzuki­Miyaura-type cross-coupling and carboboration processes are reported. The cross-couplings function well with a variety of substituted aryl iodides and aryl boronic esters and allows for orthogonal reactivity compared to palladium-catalyzed processes. The carboboration method includes both alkynes and allenes and provides access to highly substituted and stereodefined vinyl boronic esters. The alkyne carboboration method is highlighted in the simple one-pot synthesis of Tamoxifen.

19.
Curr Protoc ; 4(1): e913, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38230543

RESUMO

Environmentally enriched housing (EE) provides a stimulating and species-typical environment that enhances brain plasticity and cognition, while reducing disease severity in laboratory animals. However, standardizing EE protocols has been challenging due to issues such as variability, high pricing, or limited laboratory space. To address these challenges, we present a replicable and cost-efficient cage protocol that is accessible to researchers with limited resources and space constraints. The protocol is designed to provide a stimulating and species-typical environment for the animals. It incorporates elements such as social interaction, physical exercise, cognitive stimulation, manipulable objects, environmental variability, and sensory stimulation. As evidenced in our previous studies using our protocol, users can expect to observe similar neuroplastic and health-wise benefits that accompany EE experimental paradigms. These included straightforward step-by-step guide, which allows for construction of functional EE cages in under 8 hr. Basic knowledge of 3D printing and laser cutting is required, but no advanced skills are necessary. The protocol enables researchers to create stimulating and replicable environments that promote animal welfare, enhance brain plasticity, and yield valuable experimental results for low cost. © 2024 Wiley Periodicals LLC. Basic Protocol: An effective and cost-efficient environmental enrichment cage designed to encourage standardization amongst laboratory protocols.


Assuntos
Cognição , Meio Ambiente , Camundongos , Animais , Exercício Físico
20.
Brain Res Bull ; 200: 110701, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37422090

RESUMO

Illness is often predicated long before the manifestation of its symptoms. Exposure to stressful experiences particularly during critical periods of development, such as puberty and adolescence, can induce various physical and mental illnesses. Puberty is a critical period of maturation for neuroendocrine systems, such as the hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-adrenal (HPA) axes. Exposure to adverse experiences during puberty can impede normal brain reorganizing and remodelling and result in enduring consequences on brain functioning and behaviour. Stress responsivity differs between the sexes during the pubertal period. This sex difference is partly due to differences in circulating sex hormones between males and females, impacting stress and immune responses differently. The effects of stress during puberty on physical and mental health remains under-examined. The purpose of this review is to summarize the most recent findings pertaining to age and sex differences in HPA axis, HPG axis, and immune system development, and describe how disruption in the functioning of these systems can propagate disease. Lastly, we delve into the notable neuroimmune contributions, sex differences, and the mediating role of the gut microbiome on stress and health outcomes. Understanding the enduring consequences of adverse experiences during puberty on physical and mental health will allow a greater proficiency in treating and preventing stress-related diseases early in development.


Assuntos
Sistema Hipotálamo-Hipofisário , Sistema Hipófise-Suprarrenal , Adolescente , Humanos , Masculino , Feminino , Puberdade/fisiologia , Caracteres Sexuais , Encéfalo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa