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1.
New Phytol ; 237(6): 2467-2477, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36478218

RESUMO

Buckwheat is an important crop which originated in China and spread widely across Eurasia. However, exactly where in China domestication took place remains controversial. Archaeological and palynological records suggest a longer cultivation history of buckwheat in northern China than in southwestern China, but this conflicts with phylogenetic evidence implicating southwestern China as the centre of origin and diversity of buckwheat. We investigate alternative methodologies for inferring the occurrence of buckwheat cultivation and suggest that relative abundance could provide a reliable measure for distinguishing between wild and cultivated buckwheat in both present-day and fossil samples. Approximately 12 800-yr palaeoecological record shows that Fagopyrum pollen occurred only infrequently before the early Holocene. As southwestern China entered the early agricultural period, c. 8000-7000 yr ago, a slight increase in abundance of Fagopyrum pollen was observed. Approximately 4000 yr ago, concurrent with the Pu minority beginning to develop dry-land agriculture, the abundance of Fagopyrum pollen increased significantly, suggesting the cultivation of this crop. Fagopyrum pollen rose to a maximum value c. 1270 yr ago, suggesting an intensification of agricultural activity. These findings fill a gap in the Fagopyrum pollen record in southwestern China and provide new indications that early cultivation may have occurred in this region.


Assuntos
Fagopyrum , Filogenia , China , Agricultura , Pólen
2.
J Immunol ; 205(3): 699-707, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32591402

RESUMO

The success of the shock and kill strategy for the HIV cure depends both on the reactivation of the latent reservoir and on the ability of the immune system to eliminate infected cells. As latency reversal alone has not shown any impact in the size of the latent reservoir, ensuring that effector CTLs are able to recognize and kill HIV-infected cells could contribute to reservoir reduction. In this study, we investigated which functional aspects of human CTLs are associated with a better capacity to kill HIV-infected CD4+ T cells. We isolated Gag- and Nef-specific CTL clones with different TCR sequences from the PBMC of donors in acute and chronic infection. High-affinity clonotypes that showed IFN-γ production preserved even when the CD8 coreceptor was blocked, and clones with high Ag sensitivity exhibited higher efficiency at reducing the latent reservoir. Although intrinsic cytotoxic capacity did not differ according to TCR affinity, clonotypes with high TCR affinity showed a better ability to kill HIV-infected CD4+ T cells obtained from in vivo-infected PBMC and subjected to viral reactivation. Strategies aiming to specifically boost and maintain long-living memory CTLs with high TCR affinity in vivo prior to latency-reversing treatment might improve the efficacy of the shock and kill approach to reduce the latent reservoir.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , HIV-1/fisiologia , Receptores de Antígenos de Linfócitos T/imunologia , Latência Viral/imunologia , Linfócitos T CD4-Positivos/virologia , Humanos , Interferon gama/imunologia
3.
J Neurochem ; 152(6): 697-709, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31782806

RESUMO

Systemic inflammation can exacerbate symptoms of many neurological diseases. This effect may be facilitated by glial cells of the central nervous system (CNS) that alter their transcriptional responses and up-regulate cytokine and chemokine expression which can, in turn trigger immune surveillance. In this study, we sought to determine the effects of pro-inflammatory cytokine stimulation (TNF, IL-1α, IL-1ß) on astrocyte and microglia chemokine secretion. Primary cultures of astrocytes or microglia were stimulated with the recombinant cytokines and the levels of secreted chemokines were semi-quantitatively determined using a chemokine-specific proteome profiler array and densitometry. Pharmacological inhibitors were used to determine the effects of p38 MAPK, JNK, ERK1/2, NFkB, and transforming growth factor beta-associated kinase 1 (TAK1) in controlling chemokine production. Finally, neutrophil migration assays were performed to demonstrate functionality. Our data show that stimulated astrocytes secrete at least eight chemokines as a response to cytokine stimulation. These include those involved in neutrophil chemo-attraction and proved capable of promoting neutrophil migration in vitro. In contrast, microglia up-regulated few chemokines in response to cytokine stimulation and did not promote neutrophil migration. However, microglia readily secreted chemokines following stimulation with the toll-like receptor agonists. Finally, we show that both the production of chemokines and neutrophil migration resulting from cytokine stimulation of astrocytes was dependent on TAK1 signaling. Collectively, this study adds to the understanding of how astrocytes and microglia respond to stimuli and their role in promoting neutrophil migration to the CNS during inflammatory conditions.


Assuntos
Astrócitos/fisiologia , Movimento Celular/fisiologia , Quimiocinas/metabolismo , Citocinas/farmacologia , MAP Quinase Quinase Quinases/fisiologia , Animais , Astrócitos/enzimologia , Células Cultivadas , Quimiocinas/análise , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Feminino , Inflamação/fisiopatologia , Lipopolissacarídeos/farmacologia , MAP Quinase Quinase Quinases/antagonistas & inibidores , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Microglia/fisiologia , Neutrófilos/fisiologia , Transdução de Sinais/fisiologia
4.
Nature ; 512(7512): 74-7, 2014 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-25042999

RESUMO

The viral reservoir represents a critical challenge for human immunodeficiency virus type 1 (HIV-1) eradication strategies. However, it remains unclear when and where the viral reservoir is seeded during acute infection and the extent to which it is susceptible to early antiretroviral therapy (ART). Here we show that the viral reservoir is seeded rapidly after mucosal simian immunodeficiency virus (SIV) infection of rhesus monkeys and before systemic viraemia. We initiated suppressive ART in groups of monkeys on days 3, 7, 10 and 14 after intrarectal SIVMAC251 infection. Treatment with ART on day 3 blocked the emergence of viral RNA and proviral DNA in peripheral blood and also substantially reduced levels of proviral DNA in lymph nodes and gastrointestinal mucosa as compared with treatment at later time points. In addition, treatment on day 3 abrogated the induction of SIV-specific humoral and cellular immune responses. Nevertheless, after discontinuation of ART following 24 weeks of fully suppressive therapy, virus rebounded in all animals, although the monkeys that were treated on day 3 exhibited a delayed viral rebound as compared with those treated on days 7, 10 and 14. The time to viral rebound correlated with total viraemia during acute infection and with proviral DNA at the time of ART discontinuation. These data demonstrate that the viral reservoir is seeded rapidly after intrarectal SIV infection of rhesus monkeys, during the 'eclipse' phase, and before detectable viraemia. This strikingly early seeding of the refractory viral reservoir raises important new challenges for HIV-1 eradication strategies.


Assuntos
Macaca mulatta/virologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/crescimento & desenvolvimento , Carga Viral , Viremia/virologia , Animais , Antirretrovirais/administração & dosagem , Antirretrovirais/farmacologia , Antirretrovirais/uso terapêutico , Portador Sadio/tratamento farmacológico , Portador Sadio/virologia , DNA Viral/análise , DNA Viral/biossíntese , DNA Viral/sangue , Modelos Animais de Doenças , Feminino , Cinética , Macaca mulatta/imunologia , Masculino , Provírus/genética , RNA Viral/sangue , Reto/virologia , Síndrome de Imunodeficiência Adquirida dos Símios/tratamento farmacológico , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/efeitos dos fármacos , Vírus da Imunodeficiência Símia/imunologia , Vírus da Imunodeficiência Símia/fisiologia , Fatores de Tempo , Falha de Tratamento , Carga Viral/efeitos dos fármacos , Viremia/tratamento farmacológico , Replicação Viral/efeitos dos fármacos
5.
Proc Natl Acad Sci U S A ; 114(30): E6107-E6116, 2017 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-28696309

RESUMO

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. Most MS patients experience periods of symptom exacerbation (relapses) followed by periods of partial recovery (remission). Interestingly, upper-respiratory viral infections increase the risk for relapse. Here, we used an autoimmune-prone T-cell receptor transgenic mouse (2D2) and a mouse-adapted human influenza virus to test the hypothesis that upper-respiratory viral infection can cause glial activation, promote immune cell trafficking to the CNS, and trigger disease. Specifically, we inoculated 2D2 mice with influenza A virus (Puerto Rico/8/34; PR8) and then monitored them for symptoms of inflammatory demyelination. Clinical and histological experimental autoimmune encephalomyelitis was observed in ∼29% of infected 2D2 mice. To further understand how peripheral infection could contribute to disease onset, we inoculated wild-type C57BL/6 mice and measured transcriptomic alterations occurring in the cerebellum and spinal cord and monitored immune cell surveillance of the CNS by flow cytometry. Infection caused temporal alterations in the transcriptome of both the cerebellum and spinal cord that was consistent with glial activation and increased T-cell, monocyte, and neutrophil trafficking to the brain at day 8 post infection. Finally, Cxcl5 expression was up-regulated in the brains of influenza-infected mice and was elevated in cerebrospinal fluid of MS patients during relapse compared with specimens acquired during remission. Collectively, these data identify a mechanism by which peripheral infection may exacerbate MS as well as other neurological diseases.


Assuntos
Encefalomielite Autoimune Experimental/complicações , Infecções por Orthomyxoviridae/complicações , Animais , Cerebelo/imunologia , Cerebelo/metabolismo , Quimiocina CXCL5/imunologia , Quimiocina CXCL5/metabolismo , Encefalomielite Autoimune Experimental/genética , Vigilância Imunológica , Alphainfluenzavirus , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Medula Espinal/imunologia , Medula Espinal/metabolismo , Transcriptoma
6.
Nature ; 503(7475): 224-8, 2013 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-24172905

RESUMO

Human immunodeficiency virus type 1 (HIV-1)-specific monoclonal antibodies with extraordinary potency and breadth have recently been described. In humanized mice, combinations of monoclonal antibodies have been shown to suppress viraemia, but the therapeutic potential of these monoclonal antibodies has not yet been evaluated in primates with an intact immune system. Here we show that administration of a cocktail of HIV-1-specific monoclonal antibodies, as well as the single glycan-dependent monoclonal antibody PGT121, resulted in a rapid and precipitous decline of plasma viraemia to undetectable levels in rhesus monkeys chronically infected with the pathogenic simian-human immunodeficiency virus SHIV-SF162P3. A single monoclonal antibody infusion afforded up to a 3.1 log decline of plasma viral RNA in 7 days and also reduced proviral DNA in peripheral blood, gastrointestinal mucosa and lymph nodes without the development of viral resistance. Moreover, after monoclonal antibody administration, host Gag-specific T-lymphocyte responses showed improved functionality. Virus rebounded in most animals after a median of 56 days when serum monoclonal antibody titres had declined to undetectable levels, although, notably, a subset of animals maintained long-term virological control in the absence of further monoclonal antibody infusions. These data demonstrate a profound therapeutic effect of potent neutralizing HIV-1-specific monoclonal antibodies in SHIV-infected rhesus monkeys as well as an impact on host immune responses. Our findings strongly encourage the investigation of monoclonal antibody therapy for HIV-1 in humans.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , HIV-1/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/terapia , Vírus da Imunodeficiência Símia/fisiologia , Animais , DNA Viral/sangue , Anticorpos Anti-HIV/imunologia , Macaca mulatta , Linfócitos T/imunologia , Viremia/terapia
7.
Planta ; 248(2): 323-346, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29725817

RESUMO

MAIN CONCLUSION: The exceptionally complex exine of Echinops, representing a significant investment of energy, develops from an elaborate glycocalyx which establishes, by self-assembly, a multi-layered system of micelles upon which sporopollenin polymerizes. We report on pollen development in two species of Echinops (Asteraceae, Cynareae) studied using transmission and scanning electron microscopy with an emphasis on the organisation and development of the massive sporoderm (maximum thickness 18 µm). The major events of exine deposition during the tetrad stage follow the now familiar sequence of self-assembling micellar mesophases and the subsequent incorporation of sporopollenin, observed here as: (1) spherical units with light cores; (2) columns of spherical units with dark cores; (3) large branched macromolecules arranged in a dendritic, three-dimensional network of long alveoli; and (4) alveoli with electron-transparent cores and dense walls. Later, (5) the primexine exhibits an elongated-alveolate pattern in which the alveoli have electron-dense cores and lighter exteriors. When (6) the thick inner columellae make contact with the outer primexine, sporopollenin accumulation in the cores of the primexine alveolae establishes continuity between the inner and outer columellae. In the free microspore stage, (7) the foot layer and first lamellae of the endexine appear (8). The endexine lamellae then increase in number and massive accumulation of sporopollenin occurs on all exine elements, making individual elements such as tectal spines, more pronounced. These and earlier findings, as well as experimental simulations of exine development, show that pollen wall morphogenesis involves a subtle interplay of gene-driven biological processes and physico-chemical factors offering abundant opportunities for the generation of complex, taxon-specific patterns.


Assuntos
Biopolímeros/metabolismo , Carotenoides/metabolismo , Echinops (Planta)/crescimento & desenvolvimento , Pólen/crescimento & desenvolvimento , Ontologias Biológicas , Parede Celular/ultraestrutura , Echinops (Planta)/ultraestrutura , Micelas , Microscopia Eletrônica de Varredura , Pólen/ultraestrutura
8.
J Virol ; 89(3): 1512-22, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25410856

RESUMO

UNLABELLED: Adenovirus vectors are widely used as vaccine candidates for a variety of pathogens, including HIV-1. To date, human and chimpanzee adenoviruses have been explored in detail as vaccine vectors. The phylogeny of human and chimpanzee adenoviruses is overlapping, and preexisting humoral and cellular immunity to both are exhibited in human populations worldwide. More distantly related adenoviruses may therefore offer advantages as vaccine vectors. Here we describe the primary isolation and vectorization of three novel adenoviruses from rhesus monkeys. The seroprevalence of these novel rhesus monkey adenovirus vectors was extremely low in sub-Saharan Africa human populations, and these vectors proved to have immunogenicity comparable to that of human and chimpanzee adenovirus vaccine vectors in mice. These rhesus monkey adenoviruses phylogenetically clustered with the poorly described adenovirus species G and robustly stimulated innate immune responses. These novel adenoviruses represent a new class of candidate vaccine vectors. IMPORTANCE: Although there have been substantial efforts in the development of vaccine vectors from human and chimpanzee adenoviruses, far less is known about rhesus monkey adenoviruses. In this report, we describe the isolation and vectorization of three novel rhesus monkey adenoviruses. These vectors exhibit virologic and immunologic characteristics that make them attractive as potential candidate vaccine vectors for both HIV-1 and other pathogens.


Assuntos
Adenoviridae/classificação , Adenoviridae/isolamento & purificação , Portadores de Fármacos/isolamento & purificação , Vetores Genéticos/isolamento & purificação , Adenoviridae/genética , Adenoviridae/imunologia , Infecções por Adenoviridae/imunologia , Infecções por Adenoviridae/veterinária , Infecções por Adenoviridae/virologia , África Subsaariana , Animais , Anticorpos Antivirais/sangue , Análise por Conglomerados , DNA Viral/química , DNA Viral/genética , Humanos , Macaca mulatta , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Estudos Soroepidemiológicos , Vacinas Sintéticas/genética
9.
J Virol ; 88(11): 6243-54, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24648461

RESUMO

UNLABELLED: Prime-boost immunization regimens have proven efficacious at generating robust immune responses. However, whether the level of replication of the boosting antigen impacts the magnitude and protective efficacy of vaccine-elicited immune responses remains unclear. To evaluate this, we primed mice with replication-defective adenovirus vectors expressing the lymphocytic choriomeningitis virus (LCMV) glycoprotein (GP), followed by boosting with either LCMV Armstrong, which is rapidly controlled, or LCMV CL-13, which leads to a more prolonged exposure to the boosting antigen. Although priming of naive mice with LCMV CL-13 normally results in T cell exhaustion and establishment of chronic infection, boosting with CL-13 resulted in potent recall CD8 T cell responses that were greater than those following boosting with LCMV Armstrong. Furthermore, following the CL-13 boost, a greater number of anamnestic CD8 T cells localized to the lymph nodes, exhibited granzyme B expression, and conferred improved protection against Listeria and vaccinia virus challenges compared with the Armstrong boost. Overall, our findings suggest that the replicative capacity of the boosting antigen influences the protective efficacy afforded by prime-boost vaccine regimens. These findings are relevant for optimizing vaccine candidates and suggest a benefit of robustly replicating vaccine vectors. IMPORTANCE: The development of optimal prime-boost vaccine regimens is a high priority for the vaccine development field. In this study, we compared two boosting antigens with different replicative capacities. Boosting with a more highly replicative vector resulted in augmented immune responses and improved protective efficacy.


Assuntos
Imunidade Heteróloga/imunologia , Imunização Secundária/métodos , Vacinas Virais/imunologia , Replicação Viral/fisiologia , Adenoviridae , Animais , Antígenos Heterófilos/imunologia , Linfócitos T CD8-Positivos/imunologia , Feminino , Citometria de Fluxo , Vetores Genéticos , Glicoproteínas/metabolismo , Estimativa de Kaplan-Meier , Listeria/imunologia , Vírus da Coriomeningite Linfocítica/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Estatísticas não Paramétricas , Vaccinia virus/imunologia
11.
Trends Plant Sci ; 28(7): 731-733, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37188556

RESUMO

China has an in situ conservation system built around national parks, and has begun establishing an ex situ conservation system led by National Botanical Gardens. We highlight how this National Botanical Gardens system will serve the global biodiversity conservation goal of harmonious coexistence between humans and nature.


Assuntos
Conservação dos Recursos Naturais , Desenvolvimento Sustentável , Humanos , Plantas , Biodiversidade , China
12.
Cancer Discov ; 11(11): 2828-2845, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34230008

RESUMO

Mutations in the STK11 (LKB1) gene regulate resistance to PD-1/PD-L1 blockade. This study evaluated this association in patients with nonsquamous non-small cell lung cancer (NSCLC) enrolled in three phase I/II trials. STK11 mutations were associated with resistance to the anti-PD-L1 antibody durvalumab (alone/with the anti-CTLA4 antibody tremelimumab) independently of KRAS mutational status, highlighting STK11 as a potential driver of resistance to checkpoint blockade. Retrospective assessments of tumor tissue, whole blood, and serum revealed a unique immune phenotype in patients with STK11 mutations, with increased expression of markers associated with neutrophils (i.e., CXCL2, IL6), Th17 contexture (i.e., IL17A), and immune checkpoints. Associated changes were observed in the periphery. Reduction of STAT3 in the tumor microenvironment using an antisense oligonucleotide reversed immunotherapy resistance in preclinical STK11 knockout models. These results suggest that STK11 mutations may hinder response to checkpoint blockade through mechanisms including suppressive myeloid cell biology, which could be reversed by STAT3-targeted therapy. SIGNIFICANCE: Patients with nonsquamous STK11-mutant (STK11mut) NSCLC are less likely than STK11 wild-type (STK11wt) patients to respond to anti-PD-L1 ± anti-CTLA4 immunotherapies, and their tumors show increased expression of genes and cytokines that activate STAT3 signaling. Preclinically, STAT3 modulation reverses this resistance, suggesting STAT3-targeted agents as potential combination partners for immunotherapies in STK11mut NSCLC.This article is highlighted in the In This Issue feature, p. 2659.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Quinases Proteína-Quinases Ativadas por AMP , Anticorpos Monoclonais , Anticorpos Monoclonais Humanizados , Antígeno B7-H1/metabolismo , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação , Proteínas Serina-Treonina Quinases/genética , Estudos Retrospectivos , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Microambiente Tumoral
13.
Trends Plant Sci ; 24(1): 4-6, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30409685

RESUMO

Since 2005, a new conservation action concept has been implemented to address the most threatened plant species requiring priority conservation in China. The concept is now widely recognized at different levels of governmental departments and by the general public, and is leading to great achievements for plant conservation in China.


Assuntos
Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Plantas , China
14.
Protoplasma ; 256(2): 555-574, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30341717

RESUMO

By a detailed ontogenetic study of Ambrosia trifida pollen, tracing each stage of development with TEM, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Ambrosia trifida, observed in the microspore periplasmic space, are as follows: spherical units, gradually transforming into columns, then to rod-like units; the appearance of the initial reticulate tectum; growth of columellae under the tectum and initial sporopollenin accumulation on them; the appearance of the endexine lamellae, first in fragments, then in long laminae; the cessation of the glycocalyx growth and its detachment from the plasma membrane, resulting in the appearance of gaps; massive accumulation of sporopollenin on the tectum, columellae, and endexine, and the appearance of the foot layer at the young post-tetrad stage, accompanied by establishment of caveae in sites of the former gaps; and final massive sporopollenin accumulation. This sequence of developmental events in all probability corresponds to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental modeling of exine) strong evidence that the genome and self-assembly share control of exine formation. In this sense, self-assembly itself can be seen as an inherent mechanism of evolution.


Assuntos
Ambrosia/química , Asteraceae/química , Pólen/química
15.
PLoS One ; 12(2): e0171967, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28182711

RESUMO

The Hengduan Mountains, with a distinct altitudinal differentiation and strong vertical vegetation zonation, occupy an important position in southwestern China as a global hotspot of biodiversity. Pollen analysis of lake sediments sampled along an altitudinal gradient in this region helps us to understand how this vegetation zonation arose and how it has responded to climate change and human impacts through time. Here we present a ~30-ka pollen record and interpret it in terms of vegetational and climatic change from a 310 cm-long core from Shudu Lake, located in the Hengduan Mountains region. Our results suggest that from 30 to 22 cal. ka BP, the vegetation was dominated by steppe/grassland (comprising mainly Artemisia, Poaceae and Polygonaceae) and broad-leaved forest (primarily Quercus, Betula and Castanopsis) in the lake catchment, reflecting a relatively warm, wet climate early in this phase and slightly warmer, drier conditions late in the phase. The period between 22 and 13.9 cal. ka BP was marked by a large expansion of needle- and broad-leaved mixed forest (Pinus, Abies and Quercus) and a decline in the extent of steppe/grassland, indicating warming, drying climatic conditions followed by a cold, wet period. Between 13.9 and 3 cal. ka BP, steppe/grassland expanded and the area covered by needle- and broad-leaved mixed forest reduced, implying a fluctuating climate dominated by warm and humid conditions. After 3 cal. ka BP, the vegetation was characterized by an increase in needle-leaved forest and reduction in steppe/grassland, suggesting warming and drying climate. A synthesis of palynological investigations from this and other sites suggests that the vegetation succession patterns seen along an altitudinal gradient in northwestern Yunnan since the Late Pleistocene are comparable, but that each site has its own characteristics probably due to the influences of altitude, topography, microclimate and human impact.


Assuntos
Biodiversidade , Clima , Florestas , Fósseis , Pólen/química , Altitude , Evolução Biológica , China , Lagos , Datação Radiométrica , Árvores/fisiologia
16.
Science ; 347(6219): 278-82, 2015 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-25593185

RESUMO

CD4 T cells promote innate and adaptive immune responses, but how vaccine-elicited CD4 T cells contribute to immune protection remains unclear. We evaluated whether induction of virus-specific CD4 T cells by vaccination would protect mice against infection with chronic lymphocytic choriomeningitis virus (LCMV). Immunization with vaccines that selectively induced CD4 T cell responses resulted in catastrophic inflammation and mortality after challenge with a persistent strain of LCMV. Immunopathology required antigen-specific CD4 T cells and was associated with a cytokine storm, generalized inflammation, and multi-organ system failure. Virus-specific CD8 T cells or antibodies abrogated the pathology. These data demonstrate that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger lethal immunopathology.


Assuntos
Infecções por Arenaviridae/imunologia , Linfócitos T CD4-Positivos/imunologia , Doenças do Sistema Imunitário/etiologia , Inflamação/etiologia , Vírus da Coriomeningite Linfocítica/imunologia , Vacinas Virais/efeitos adversos , Vacinas Virais/imunologia , Imunidade Adaptativa , Animais , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Infecções por Arenaviridae/virologia , Linfócitos T CD8-Positivos/imunologia , Citocinas/sangue , Epitopos de Linfócito T/imunologia , Doenças do Sistema Imunitário/imunologia , Doenças do Sistema Imunitário/patologia , Memória Imunológica , Inflamação/imunologia , Inflamação/patologia , Vírus da Coriomeningite Linfocítica/fisiologia , Camundongos Endogâmicos C57BL , Insuficiência de Múltiplos Órgãos/etiologia , Vacinação , Carga Viral , Replicação Viral
17.
Nat Commun ; 5: 3855, 2014 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-24804694

RESUMO

The pollen wall, an essential structure for pollen function, consists of two layers, an inner intine and an outer exine. The latter is further divided into sexine and nexine. Many genes involved in sexine development have been reported, in which the MYB transcription factor Male Sterile 188 (MS188) specifies sexine in Arabidopsis. However, nexine formation remains poorly understood. Here we report the knockout of TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK) leads to nexine absence in Arabidopsis. TEK encodes an AT-hook nuclear localized family protein highly expressed in tapetum during the tetrad stage. Absence of nexine in tek disrupts the deposition of intine without affecting sexine formation. We find that ABORTED MICROSPORES directly regulates the expression of TEK and MS188 in tapetum for the nexine and sexine formation, respectively. Our data show that a transcriptional cascade in the tapetum specifies the development of pollen wall.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Pólen/genética , Sequência de Aminoácidos , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Parede Celular/fisiologia , Flores/genética , Regulação da Expressão Gênica de Plantas , Pólen/metabolismo , Pólen/fisiologia
18.
Bot J Linn Soc ; 166(3): 267-81, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22059248

RESUMO

The need for action on the global environment is now well understood and governments, agencies, non-governmental organizations and botanic gardens have all been working in their various ways to promote environmental sustainability and reduce species and habitat loss for at least 10­20 years. The Global Strategy for Plant Conservation (GSPC) has been widely adopted, particularly by the botanic garden community, and has resulted in many successes despite failing to achieve its ultimate goal of halting the loss of plant biodiversity. The objectives and targets for Phase 2 of the GSPC, running from 2010 to 2020, mirror those of Phase 1 and had been largely agreed prior to their formal adoption at the Conference of the Parties to the Convention on Biological Diversity in Nagoya in October 2010. However, to be successful, the scientific contribution of botanic gardens needs to be strengthened, as does government policy and commitment. Botanic garden research to underpin conservation action, including the role of botanic garden horticulture, training and international capacity building, has a major part to play and needs to be better understood and better coordinated. We provide examples based on the experience of the Royal Botanic Garden Edinburgh in the UK and overseas. Government policy, at national and international levels, needs to reflect the fundamental importance of plant diversity in maintaining the biosphere and supporting humanity. The commitment of significant new resources is an essential prerequisite for success, but this needs to be well coordinated, inclusive of all stakeholders and carefully targeted. A further challenge is the need to integrate better the plant diversity-related activities of what are currently diverse and disconnected sectors, including agriculture, forestry, protected area management and botanic gardens.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Jardinagem , Governo , Plantas , Saúde Pública , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/história , Conservação dos Recursos Naturais/legislação & jurisprudência , Jardinagem/economia , Jardinagem/educação , Jardinagem/história , Governo/história , História do Século XX , História do Século XXI , Internacionalidade/história , Saúde Pública/economia , Saúde Pública/educação , Saúde Pública/história , Política Pública/economia , Política Pública/história , Política Pública/legislação & jurisprudência , Pesquisadores/economia , Pesquisadores/educação , Pesquisadores/história
19.
Cladistics ; 2(3): 358-362, 1986 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34949055
20.
Cladistics ; 3(2): 185-195, 1987 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34949078
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