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1.
Proc Natl Acad Sci U S A ; 119(25): e2202932119, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35696563

RESUMO

The primary insect steroid hormone ecdysone requires a membrane transporter to enter its target cells. Although an organic anion-transporting polypeptide (OATP) named Ecdysone Importer (EcI) serves this role in the fruit fly Drosophila melanogaster and most likely in other arthropod species, this highly conserved transporter is apparently missing in mosquitoes. Here we report three additional OATPs that facilitate cellular incorporation of ecdysone in Drosophila and the yellow fever mosquito Aedes aegypti. These additional ecdysone importers (EcI-2, -3, and -4) are dispensable for development and reproduction in Drosophila, consistent with the predominant role of EcI. In contrast, in Aedes, EcI-2 is indispensable for ecdysone-mediated development, whereas EcI-4 is critical for vitellogenesis induced by ecdysone in adult females. Altogether, our results indicate unique and essential functions of these additional ecdysone importers in mosquito development and reproduction, making them attractive molecular targets for species- and stage-specific control of ecdysone signaling in mosquitoes.


Assuntos
Aedes , Ecdisona , Proteínas de Insetos , Transportadores de Ânions Orgânicos , Aedes/crescimento & desenvolvimento , Aedes/fisiologia , Animais , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Ecdisona/metabolismo , Feminino , Proteínas de Insetos/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Vitelogênese
2.
Ann Surg Oncol ; 31(3): 1714-1724, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38006526

RESUMO

BACKGROUND: Prior studies have shown tumor specificity on the impact of longer time interval from diagnosis to surgery, however in gastric cancer (GC) this remains unclear. We aimed to determine if a longer time interval from diagnosis to surgery had an impact on lymph node (LN) upstaging and overall survival (OS) outcomes among patients with clinically node negative (cN0) GC. PATIENTS AND METHODS: Patients diagnosed with cN0 GC undergoing surgery between 2004-2018 were identified in the National Cancer Database (NCDB) and divided into intervals between time of diagnosis and surgery [short interval (SI): ≥ 4 days to < 8 weeks and long interval (LI): ≥ 8 weeks]. Multivariable regression analysis evaluated the independent impact of surgical timing on LN upstaging and a Cox proportional hazards analysis and Kaplan-Meier curves evaluated survival outcomes. RESULTS: Of 1824 patients with cN0 GC, 71.8% had a SI to surgery and 28.1% had a LI to surgery. LN upstaging was seen more often in the SI group when compared to LI group (82% versus 76%, p = 0.004). LI to surgery showed to be an independent factor protective against LN upstaging [adjusted odds ratio = 0.62, 95% CI: (0.39-0.99)]. Multivariate Cox regression analysis indicated that time to surgery was not associated with a difference in overall survival [hazard ratio (HR) = 0.91, 95% CI: (0.71-1.17)], however uncontrolled Kaplan-Meier curves showed OS difference between the SI and LI to surgery groups (p = 0.037). CONCLUSION: Timing to surgery was not a predictor of LN upstaging or overall survival, suggesting that additional medical optimization in preparation for surgery and careful preoperative staging may be appropriate in patients with node negative early stage GC without affecting outcomes.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patologia , Estadiamento de Neoplasias , Linfonodos/patologia , Modelos de Riscos Proporcionais , Análise Multivariada , Estudos Retrospectivos , Excisão de Linfonodo
3.
Int Nurs Rev ; 67(1): 19-34, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31364775

RESUMO

AIM: To review published literature descriptions of advanced practice nurses' roles in low- and lower middle-income countries. BACKGROUND: Advanced practice nurse roles have the potential to address insufficient healthcare resources in low- and lower middle-income countries. INTRODUCTION: This integrative review highlights advanced practice nurses' roles in the delivery of healthcare services in low- and lower middle-income countries. METHODS: Three electronic databases PubMed, CINAHL complete and ProQuest Health & Medicine were searched. No limits by year or language were set. The names for low- and lower middle-income countries and combinations 'related to advanced practice nurses' titles were used to identify papers. In addition, a review of publication type was performed. Themes found within the publications were assessed against the advanced practice nurses' International Council of Nurses' characteristics. An integrative review facilitated an appraisal of the papers identified. RESULTS: The initial search identified 5778 publications in 16 languages. This number was reduced to 23, from 18 low- and lower middle-income once exclusion criteria were applied. Six publications were from 1977 to 1999, and six between 2000 and 2010, with the remaining 11 from 2011 to 2018. Zambia had the most publications. Notably, 63 countries were not represented. Of those meeting inclusion criteria, the majority addressed education with a lesser extent focusing on practice and regulation of advanced practice nurse's roles. The majority were published during the last decade. DISCUSSION: This review of the published literature identified advanced practice nurses' roles and function within some healthcare systems. However, not all components were reported. Examination of the grey literature could provide additional information about the actual and potential benefits of advanced practice nurses' in low- and lower middle-income countries. CONCLUSION: The published literature that referred to advanced practice nurses' identified their contribution to positive impacts on health care over the last 40 years. However, with only 11 publications identified in the last 7 years, further review is required to understand the advanced practice nurses' roles in these countries. IMPLICATIONS FOR NURSING AND/OR HEALTH POLICY: Further development of advanced practice nurses' in low- and lower middle-income countries is supported by the lack of published literature.


Assuntos
Prática Avançada de Enfermagem , Países em Desenvolvimento , Papel do Profissional de Enfermagem , Atenção à Saúde , Humanos
5.
Int J Equity Health ; 17(1): 28, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29458379

RESUMO

BACKGROUND: Disparities in access to primary care (PC) have been demonstrated within and between health systems. However, few studies have assessed the factors associated with multiple barriers to access occurring along the care-seeking process in different healthcare systems. METHODS: In this secondary analysis of the 2016 Commonwealth Fund International Health Policy Survey of Adults, access was represented through participant responses to questions relating to access barriers either before or after reaching the PC practice in 11 countries (Australia, Canada, France, Germany, Norway, the Netherlands, New Zealand, Sweden, Switzerland, the United Kingdom, and United States). The number of respondents in each country ranged from 1000 to 7000 and the response rates ranged from 11% to 47%. We used multivariable logistic regression models within each of eleven countries to identify disparities in response to the access barriers by age, sex, immigrant status, income and the presence of chronic conditions. RESULTS: Overall, one in five adults (21%) experienced multiple barriers before reaching PC practices. After reaching care, an average of 16% of adults had two or more barriers. There was a sixfold difference between nations in the experience of these barriers to access. Vulnerable groups experiencing multiple barriers were relatively consistent across countries. People with lower income were more likely to experience multiple barriers, particularly before reaching primary care practices. Respondents with mental health problems and those born outside the country displayed substantial vulnerability in terms of barriers after reaching care. CONCLUSION: A greater understanding of the multiple barriers to access to PC across the stages of the care-seeking process may help to inform planning and performance monitoring of disparities in access. Variation across countries may reveal organisational and system drivers of access, and inform efforts to improve access to PC for vulnerable groups. The cumulative nature of these barriers remains to be assessed.


Assuntos
Pesquisas sobre Atenção à Saúde/estatística & dados numéricos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Disparidades em Assistência à Saúde/estatística & dados numéricos , Internacionalidade , Atenção Primária à Saúde , Fatores Etários , Idoso , Feminino , Saúde Global , Humanos , Masculino , Fatores Sexuais , Fatores Socioeconômicos , Estados Unidos
6.
Curr Oncol ; 24(1): 23-27, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28270721

RESUMO

BACKGROUND: The treatment of children with cancer is associated with significant burden for the entire family. Frequent clinic visits and extended hospital stays can negatively affect quality of life for children and their families. METHODS: Here, we describe the development of a Hospital at Home program (H@H) that delivers therapy to pediatric hematology, oncology, and blood and marrow transplant (bmt) patients in their homes. The services provided include short infusions of chemotherapy, supportive-care interventions, antibiotics, post-chemotherapy hydration, and teaching. RESULTS: From 2013 to 2015, the H@H program served 136 patients, making 1701 home visits, for patients mainly between the ages of 1 and 4 years. Referrals came from oncology in 82% of cases, from hematology in 11%, and from bmt in 7%. Since inception of the program, no adverse events have been reported. Family surveys suggested less disruption in daily routines and appreciation of specialized care by hematology and oncology nurses. Staff surveys highlighted a perceived benefit of H@H in contributing to early discharge of patients by supporting out-of-hospital monitoring and teaching. CONCLUSIONS: The development of a H@H program dedicated to the pediatric hematology, oncology, or bmt patient appears feasible. Our pilot program offers a potential contribution to improvement in patient quality of life and in cost-benefit for parents and the health care system.

7.
FASEB J ; 29(4): 1404-13, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25550465

RESUMO

Akt signaling regulates diverse physiologies in a wide range of organisms. We examine the impact of increased Akt signaling in the fat body of 2 mosquito species, the Asian malaria mosquito Anopheles stephensi and the yellow fever mosquito Aedes aegypti. Overexpression of a myristoylated and active form of A. stephensi and Ae. aegypti Akt in the fat body of transgenic mosquitoes led to activation of the downstream signaling molecules forkhead box O (FOXO) and p70 S6 kinase in a tissue and blood meal-specific manner. In both species, increased Akt signaling in the fat body after blood feeding significantly increased adult survivorship relative to nontransgenic sibling controls. In A. stephensi, survivorship was increased by 15% to 45%, while in Ae. aegypti, it increased 14% to 47%. Transgenic mosquitoes fed only sugar, and thus not expressing active Akt, had no significant difference in survivorship relative to nontransgenic siblings. Expression of active Akt also increased expression of fat body vitellogenin, but the number of viable eggs did not differ significantly between transgenic and nontransgenic controls. This work demonstrates a novel mechanism of enhanced survivorship through increased Akt signaling in the fat bodies of multiple mosquito genera and provides new tools to unlock the molecular underpinnings of aging in eukaryotic organisms.


Assuntos
Aedes/metabolismo , Anopheles/metabolismo , Corpo Adiposo/metabolismo , Proteínas de Insetos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Aedes/genética , Aedes/crescimento & desenvolvimento , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Animais Geneticamente Modificados , Anopheles/genética , Anopheles/crescimento & desenvolvimento , Feminino , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Proteínas de Insetos/genética , Longevidade/genética , Longevidade/fisiologia , Proteínas Proto-Oncogênicas c-akt/genética , Reprodução/genética , Reprodução/fisiologia , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Transdução de Sinais , Especificidade da Espécie , Vitelogeninas/genética , Vitelogeninas/metabolismo
8.
J Biol Chem ; 288(50): 35801-11, 2013 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-24158439

RESUMO

Glutamine synthetase (GS), which catalyzes the production of glutamine, plays essential roles in nitrogen metabolism. There are two main bacterial GS isoenzymes, GSI-α and GSI-ß. GSI-α enzymes, which have not been structurally characterized, are uniquely feedback-inhibited by Gln. To gain insight into GSI-α function, we performed biochemical and cellular studies and obtained structures for all GSI-α catalytic and regulatory states. GSI-α forms a massive 600-kDa dodecameric machine. Unlike other characterized GS, the Bacillus subtilis enzyme undergoes dramatic intersubunit conformational alterations during formation of the transition state. Remarkably, these changes are required for active site construction. Feedback inhibition arises from a hydrogen bond network between Gln, the catalytic glutamate, and the GSI-α-specific residue, Arg(62), from an adjacent subunit. Notably, Arg(62) must be ejected for proper active site reorganization. Consistent with these findings, an R62A mutation abrogates Gln feedback inhibition but does not affect catalysis. Thus, these data reveal a heretofore unseen restructuring of an enzyme active site that is coupled with an isoenzyme-specific regulatory mechanism. This GSI-α-specific regulatory network could be exploited for inhibitor design against Gram-positive pathogens.


Assuntos
Bacillus subtilis/enzimologia , Biocatálise , Retroalimentação Fisiológica , Glutamato-Amônia Ligase/antagonistas & inibidores , Glutamato-Amônia Ligase/química , Multimerização Proteica , Subunidades Proteicas/química , Glutamato-Amônia Ligase/metabolismo , Glutamina/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/química , Isoenzimas/metabolismo , Cinética , Modelos Moleculares , Estrutura Quaternária de Proteína
9.
Osteoporos Int ; 24(3): 999-1006, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22744715

RESUMO

UNLABELLED: Bone mineral content (BMC) is known to be greater in the dominant arm after the age of 8 years. We studied a group of children and found that BMC sidedness gradually increased up to the age of 6 years and then remained stable into late adolescence. INTRODUCTION: Bone mineral content (BMC) exhibits sidedness in the arms after the age of 8 years, but it is not known whether BMC is greater in the dominant arm from birth or whether lateralization develops in early childhood. To address this, we examined bone mineral status in relation to handedness and age. METHODS: Subjects (N = 158) were children recently initiating glucocorticoids for underlying disease (leukemia 43 %, rheumatic conditions 39 %, nephrotic syndrome 18 %). Handedness was determined by questionnaire and BMC by dual-energy X-ray absorptiometry. RESULTS: Median age was 7.2 years (range, 1.5 to 17.0 years), 49 % was male, and the spine BMD Z-score was -0.9 (SD, 1.3). By linear regression, BMC sidedness in the arms was significantly related to age (r = 0.294, p = 0.0005). Breakpoint analysis revealed two lines with a knot at 6.0 years (95 % CI, 4.5-7.5 years). The formula for the first line was: dominant:nondominant arm BMC ratio = 0.029 × age [in years] + 0.850 (r = 0.323, p = 0.017). The slope of the second line was not different from 0 (p = 0.332), while the slopes for the two lines were significantly different (p = 0.027). CONCLUSIONS: These results show that arm BMC sidedness in this patient group develops up to age 6 years and then remains stable into late adolescence. This temporal profile is consistent with mechanical stimulation of the skeleton in response to asymmetrical muscle use as handedness becomes manifest.


Assuntos
Envelhecimento/fisiologia , Ossos do Braço/fisiologia , Densidade Óssea/fisiologia , Lateralidade Funcional/fisiologia , Absorciometria de Fóton/métodos , Adolescente , Composição Corporal/fisiologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Ossos da Perna/fisiologia , Masculino
10.
Mycoses ; 56(4): 482-7, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23437849

RESUMO

Invasive fungal infections (IFIs) are a major cause of morbidity and mortality in paediatric acute myeloid leukaemia (AML). This study describes risk factors for IFI and IFI-related sepsis in this population. We conducted a population-based, retrospective cohort study of children with AML in Canada. IFIs during chemotherapy and prior to haematopoietic stem cell transplantation, relapse, persistent disease or death were identified. Risk factors for proven or probable IFI were examined. Among courses complicated by IFI, risk factors for sepsis were also evaluated. There were 341 children with AML included of which 41 (12.0%) experienced 46 different episodes of IFI. Candida species accounted for 23 (50.0%) of IFIs and Aspergillus spp. accounted for 14 (30.4%). Days of broad-spectrum antibiotics, days of corticosteroids and neutropenia at start of the course were independently associated with IFI. Only days of fever were independently associated with IFI-related sepsis. Invasive fungal infections occurred in 12.0% of paediatric AML patients. Risk factors for IFI and IFI-related sepsis were identified. This knowledge may help to consider targeted strategies.


Assuntos
Fungemia/epidemiologia , Fungemia/microbiologia , Hospedeiro Imunocomprometido , Leucemia Mieloide Aguda/complicações , Infecções Oportunistas/epidemiologia , Infecções Oportunistas/microbiologia , Adolescente , Canadá/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Fungos/classificação , Fungos/isolamento & purificação , Humanos , Lactente , Leucemia Mieloide Aguda/tratamento farmacológico , Masculino , Prevalência , Estudos Retrospectivos , Fatores de Risco
11.
Nat Med ; 29(11): 2742-2747, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37884626

RESUMO

Blind and deaf individuals comprise large populations that often experience health disparities, with those from marginalized gender, racial, ethnic and low-socioeconomic communities commonly experiencing compounded health inequities. Including these populations in precision medicine research is critical for scientific benefits to accrue to them. We assessed representation of blind and deaf people in the All of Us Research Program (AoURP) 2018-2023 cohort of participants who provided electronic health records and compared it with the Centers for Disease Control and Prevention 2018 national estimates by key demographic characteristics and intersections thereof. Blind and deaf AoURP participants are considerably underrepresented in the cohort, especially among working-age adults (younger than age 65 years), as well as Asian and multi-racial participants. Analyses show compounded underrepresentation at the intersection of multiple marginalization (that is, racial or ethnic minoritized group, female sex, low education and low income), most substantively for working-age blind participants identifying as Black or African American female with education levels lower than high school (representing one-fifth of their national prevalence). Underrepresentation raises concerns about the generalizability of findings in studies that use these data and limited benefits for the already underserved blind and deaf populations.


Assuntos
Cegueira , Surdez , Minorias Desiguais em Saúde e Populações Vulneráveis , Saúde da População , Determinantes Sociais da Saúde , Adulto , Idoso , Feminino , Humanos , Negro ou Afro-Americano/estatística & dados numéricos , Etnicidade , Saúde da População/estatística & dados numéricos , Grupos Raciais/etnologia , Grupos Raciais/estatística & dados numéricos , Pessoa de Meia-Idade , Cegueira/epidemiologia , Surdez/epidemiologia , Minorias Desiguais em Saúde e Populações Vulneráveis/estatística & dados numéricos , Asiático/estatística & dados numéricos , Estados Unidos/epidemiologia , Masculino , Fatores Sexuais , Determinantes Sociais da Saúde/etnologia , Determinantes Sociais da Saúde/estatística & dados numéricos , Escolaridade
12.
J Bacteriol ; 193(18): 4841-8, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21764931

RESUMO

CodY is a global transcriptional regulator that is activated by branched-chain amino acids. A palindromic 15-bp sequence motif, AATTTTCNGAAAATT, is associated with CodY DNA binding. A gel mobility shift assay was used to examine the effect of pH on the binding of Bacillus subtilis CodY to the hutPp and ureAp(3) promoters. CodY at pH 6.0 has higher affinity for DNA, more enhanced activation by isoleucine, and a lower propensity for nonspecific DNA binding than CodY at pH 8.0. DNase I footprinting was used to identify the CodY-protected regions in the hutPp and ureAp(3) promoters. The CodY-protected sequences for both promoters were found to contain multiple copies of the 15-bp motif with 6-bp overlaps. Mutational analysis of the hutPp regulatory region revealed that two overlapping sequence motifs were required for CodY-mediated regulation. The presence of overlapping sequence motifs in the regulatory regions of many B. subtilis CodY-regulated genes suggests that CodY binds to native operators that contain overlapping binding sites.


Assuntos
Bacillus subtilis/genética , DNA Bacteriano/genética , Regiões Operadoras Genéticas , Fatores de Transcrição/metabolismo , Sítios de Ligação , Pegada de DNA , Análise Mutacional de DNA , Ensaio de Desvio de Mobilidade Eletroforética , Concentração de Íons de Hidrogênio , Ligação Proteica
13.
Nat Med ; 5(12): 1403-9, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10581083

RESUMO

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) damages dopaminergic neurons as seen in Parkinson disease. Here we show that after administration of MPTP to mice, there was a robust gliosis in the substantia nigra pars compacta associated with significant upregulation of inducible nitric oxide synthase (iNOS). These changes preceded or paralleled MPTP-induced dopaminergic neurodegeneration. We also show that mutant mice lacking the iNOS gene were significantly more resistant to MPTP than their wild-type littermates. This study demonstrates that iNOS is important in the MPTP neurotoxic process and indicates that inhibitors of iNOS may provide protective benefit in the treatment of Parkinson disease.


Assuntos
Intoxicação por MPTP/enzimologia , Intoxicação por MPTP/etiologia , Degeneração Neural/enzimologia , Degeneração Neural/etiologia , Óxido Nítrico Sintase/metabolismo , Doença de Parkinson/enzimologia , Doença de Parkinson/etiologia , Animais , Modelos Animais de Doenças , Dopamina/metabolismo , Inibidores Enzimáticos/farmacologia , Expressão Gênica/efeitos dos fármacos , Intoxicação por MPTP/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/efeitos dos fármacos , Microglia/enzimologia , Degeneração Neural/tratamento farmacológico , Óxido Nítrico Sintase/deficiência , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Doença de Parkinson/tratamento farmacológico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
14.
Proc Natl Acad Sci U S A ; 105(3): 1014-9, 2008 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-18195355

RESUMO

The Bacillus subtilis GlnR repressor controls gene expression in response to nitrogen availability. Because all GlnR-regulated genes are expressed constitutively in mutants lacking glutamine synthetase (GS), GS is required for repression by GlnR. Feedback-inhibited GS (FBI-GS) was shown to activate GlnR DNA binding with an in vitro electophoretic mobility shift assay (EMSA). The activation of GlnR DNA binding by GS in these experiments depended on the feedback inhibitor glutamine and did not occur with mutant GS proteins defective in regulating GlnR activity in vivo. Although stable GS-GlnR-DNA ternary complexes were not observed in the EMSA experiments, cross-linking experiments showed that a protein-protein interaction occurs between GlnR and FBI-GS. This interaction was reduced in the absence of the feedback inhibitor glutamine and with mutant GS proteins. Because FBI-GS significantly reduced the dissociation rate of the GlnR-DNA complexes, the stability of these complexes is enhanced by FBI-GS. These results argue that FBI-GS acts as a chaperone that activates GlnR DNA binding through a transient protein-protein interaction that stabilizes GlnR-DNA complexes. GS was shown to control the activity of the B. subtilis nitrogen transcription factor TnrA by forming a stable complex between FBI-GS and TnrA that inhibits TnrA DNA binding. Thus, B. subtilis GS is an enzyme with dual catalytic and regulatory functions that uses distinct mechanisms to control the activity of two different transcription factors.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Glutamato-Amônia Ligase/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas Repressoras/metabolismo , DNA/genética , Proteínas de Ligação a DNA/genética , Glutamato-Amônia Ligase/genética , Chaperonas Moleculares/genética , Mutação/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica , Proteínas Repressoras/genética
15.
Insect Biochem Mol Biol ; 139: 103669, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34666189

RESUMO

In vertebrates and invertebrates, the insulin/insulin-like growth factor 1 (IGF1) signaling (IIS) cascade is highly conserved and plays a vital role in many different physiological processes. Among the many tissues that respond to IIS in mosquitoes, the fat body has a central role in metabolism, lifespan, reproduction, and innate immunity. We previously demonstrated that fat body specific expression of active Akt, a key IIS signaling molecule, in adult Anopheles stephensi and Aedes aegypti activated the IIS cascade and extended lifespan. Additionally, we found that transgenic females produced more vitellogenin (Vg) protein than non-transgenic mosquitoes, although this did not translate into increased fecundity. These results prompted us to further examine how IIS impacts immunity, metabolism, growth and development of these transgenic mosquitoes. We observed significant changes in glycogen, trehalose, triglycerides, glucose, and protein in young (3-5 d) transgenic mosquitoes relative to non-transgenic sibling controls, while only triglycerides were significantly changed in older (18 d) transgenic mosquitoes. More importantly, we demonstrated that enhanced fat body IIS decreased both the prevalence and intensity of Plasmodium falciparum infection in transgenic An. stephensi. Additionally, challenging transgenic An. stephensi with Gram-positive and Gram-negative bacteria altered the expression of several antimicrobial peptides (AMPs) and two anti-Plasmodium genes, nitric oxide synthase (NOS) and thioester complement-like protein (TEP1), relative to non-transgenic controls. Increased IIS in the fat body of adult female An. stephensi had little to no impact on body size, growth or development of progeny from transgenic mosquitoes relative to non-transgenic controls. This study both confirms and expands our understanding of the critical roles insulin signaling plays in regulating the diverse functions of the mosquito fat body.


Assuntos
Anopheles/fisiologia , Corpo Adiposo/metabolismo , Interações Hospedeiro-Patógeno , Insulina/fisiologia , Transdução de Sinais , Animais , Anopheles/microbiologia , Anopheles/parasitologia , Feminino , Bactérias Gram-Negativas/fisiologia , Bactérias Gram-Positivas/fisiologia , Interações Hospedeiro-Parasita , Plasmodium falciparum/fisiologia
16.
J Bacteriol ; 192(19): 5018-25, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20656908

RESUMO

The enzymatic activity of Bacillus subtilis glutamine synthetase (GS), which catalyzes the synthesis of glutamine from ammonium and glutamate, is regulated by glutamine feedback inhibition. The feedback-inhibited form of B. subtilis GS regulates the DNA-binding activities of the TnrA and GlnR nitrogen transcriptional factors. Bacterial GS proteins contain a flexible seven-residue loop, the Glu304 flap, that closes over the glutamate entrance to the active site. Amino acid substitutions in Glu304 flap residues were examined for their effects on gene regulation, enzymatic activity, and feedback inhibition. Substitutions in five of the Glu304 loop residues resulted in constitutive expression of both TnrA- and GlnR-regulated genes, indicating that this flap is important for regulating the activity of these transcription factors. The residues in the highly conserved Glu304 flap appear to be optimized for glutamate binding because mutant enzymes with substitutions in five of the flap residues had increased glutamate Km values compared to that for wild-type GS. The E304A and E304D substitutions increased the ammonium Km values compared to that for wild-type GS and conferred high-level resistance to inhibition by glutamine, glycine, and methionine sulfoximine. A model for the role of the Glu304 residue in glutamine feedback inhibition is proposed.


Assuntos
Bacillus subtilis/enzimologia , Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Glutamato-Amônia Ligase/metabolismo , Bacillus subtilis/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Ensaio de Desvio de Mobilidade Eletroforética , Glutamato-Amônia Ligase/química , Glutamato-Amônia Ligase/genética , Glutamina/metabolismo , Mutagênese Sítio-Dirigida , Mutação , Estrutura Secundária de Proteína , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo
17.
J Exp Med ; 163(4): 952-71, 1986 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-3950548

RESUMO

Mouse macrophage Fc receptors specific for IgG1/IgG2b mediate the binding and pinocytic uptake of soluble IgG-containing antibody-antigen complexes. Internalization of these multivalent IgG complexes is accompanied not only by the intracellular degradation of the ligand, but also by a net decrease in the number of plasma membrane Fc receptors and an accelerated rate of receptor turnover. In contrast, internalized receptors bound to a monovalent ligand, the high affinity Fab fragment of the antireceptor mAb 2.4G2, escape degradation by rapidly recycling to the cell surface. In this paper, we have characterized the intracellular pathway involved in the endocytosis and transport of Fc receptors in the J774 macrophage cell line. The results show that the uptake of multivalent ligands follows the normal pathway of receptor-mediated endocytosis: internalization in clathrin-coated pits and coated vesicles, delivery to endosomes, and finally to acid hydrolase-rich lysosomes. Immunoprecipitation of radiolabeled receptor from Percoll density gradients showed that endocytosis of the IgG complexes also results in the concomitant transport of the receptor to lysosomes. Although uptake of the monovalent Fab fragment had no detectable effect on intracellular receptor distribution, preparations of 2.4G2 Fab rendered multivalent by adsorption to colloidal gold were as effective as the IgG complexes at causing lysosomal accumulation of internalized receptors. Thus, it is likely that the down-regulation and degradation of Fc receptors which occurs during the endocytosis of antibody-antigen complexes is due to the transport of internalized receptors to lysosomes. Moreover, the ability of certain Fc receptor-bound ligands to interfere with receptor recycling and trigger lysosomal transport seems to depend on ligand valency rather than on the presence or absence of Fc domains on intact IgG molecules.


Assuntos
Lisossomos/metabolismo , Macrófagos/imunologia , Receptores Fc/metabolismo , Animais , Complexo Antígeno-Anticorpo/metabolismo , Fracionamento Celular , Linhagem Celular , Células Cultivadas , Endocitose , Ligantes/metabolismo , Camundongos
18.
J Bacteriol ; 191(8): 2485-92, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19233925

RESUMO

Bacillus subtilis contains two nitrogen transcription factors, GlnR and TnrA. The activities of GlnR and TnrA are regulated by direct protein-protein interactions with the feedback-inhibited form of glutamine synthetase (GS). To look for other factors involved in regulating GlnR activity, we isolated mutants with constitutive glnRA expression (Gln(C)). The twenty-seven Gln(C) mutants isolated in this mutant screen all contained mutations tightly linked to the glnRA operon which encodes GlnR (glnR) and GS (glnA). Four Gln(C) mutants contained mutations in the glnR gene that most likely impair the ability of GlnR to bind DNA. Three other Gln(C) mutants contained novel glnA mutations (S55F, V173I, and L174F). GlnR regulation was completely relieved in the three glnA mutants, while only modest defects in TnrA regulation were observed. In vitro enzymatic assays showed that the purified S55F mutant enzyme was catalytically defective while the V173I and L174F enzymes were highly resistant to feedback inhibition. The V173I and L174F GS proteins were found to require higher glutamine concentrations than the wild-type GS to regulate the DNA-binding activities of GlnR and TnrA in vitro. These results are consistent with a model where feedback-inhibited GS is the only cellular factor involved in regulating the activity of GlnR in B. subtilis.


Assuntos
Bacillus subtilis/fisiologia , Regulação Bacteriana da Expressão Gênica , Glutamato-Amônia Ligase/metabolismo , Mutação de Sentido Incorreto , Substituição de Aminoácidos/genética , Bacillus subtilis/genética , Proteínas de Bactérias/metabolismo , DNA Bacteriano/metabolismo , Glutamato-Amônia Ligase/genética , Ligação Proteica , Proteínas Repressoras/metabolismo , Transativadores/genética , Transativadores/metabolismo
19.
Mol Microbiol ; 68(2): 277-85, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18331450

RESUMO

The Bacillus subtilis GlnR transcription factor regulates gene expression in response to changes in nitrogen availability. Glutamine synthetase transmits the nitrogen regulatory signal to GlnR. The DNA-binding activity of GlnR is activated by a transient protein-protein interaction with feedback-inhibited glutamine synthetase that stabilizes GlnR-DNA complexes. This signal transduction mechanism was analysed by creating mutant GlnR proteins with partial or complete truncations of their C-terminal domains. The truncated GlnR proteins were found to constitutively repress gene expression in vivo. This constitutive repression did not require glutamine synthetase. Purified mutant GlnR proteins bound DNA in vitro more tightly than wild-type GlnR protein and this binding was not activated by feedback-inhibited glutamine synthetase. While full-length GlnR is monomeric, the truncated GlnR proteins contained significant levels of dimers. These results indicate that the C-terminal region of GlnR acts as an autoinhibitory domain that prevents GlnR dimerization and thus impedes DNA binding. The GlnR C-terminal domain is also required for the interaction between GlnR and feedback-inhibited glutamine synthetase. Compared with the full-length GlnR protein, the truncated GlnR proteins were defective in their interaction with feedback-inhibited glutamine synthetase in cross-linking experiments.


Assuntos
Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/metabolismo , Regulação Bacteriana da Expressão Gênica , Glutamato-Amônia Ligase/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , DNA Bacteriano/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/isolamento & purificação , Dimerização , Ligação Proteica , Mapeamento de Interação de Proteínas , Estrutura Terciária de Proteína , Deleção de Sequência
20.
Ann Surg Oncol ; 16(9): 2579-86, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19557478

RESUMO

BACKGROUND: Decreased performance status, comorbidities, and disease natural history may erode enthusiasm for soft tissue sarcoma (STS) resection in elderly patients. Consequently, we evaluated the outcome of elderly patients amenable to complete surgical resection treated at a single institution. METHODS: Prospectively accrued data were used to identify patients with primary STS age >or=65 years (n = 325) who underwent complete macroscopic resection at our institution (1996-2007). Univariable and multivariable analyses were performed to identify prognostic factors. RESULTS: Median age at presentation was 72 years; 179 patients (55.1%) had associated comorbidities with an ASA score of >or=3. Extremity was the most common site (57.1%; n = 186), undifferentiated pleomorphic sarcoma the most common histology (60.4%; n = 197); 232 (71.2%) were high grade, 222 (68.3%) were >5 cm. Thirty-day postoperative mortality was 0.9% (n = 3); overall complication rate was 30.7% (n = 100), and mean postoperative hospital stay was 9 days (range, 1-84). Estimated median survival was 96 months, 5-year disease-specific survival (DSS) was 63%. Multivariable analysis identified age >or=75 year (HR = 2.03), tumor size: 5-15 vs <5 cm (HR = 3.54), or >15 vs <5 cm (HR = 10.33), and high-grade (HR = 5.53) as significant independent adverse prognostic factors. Compared with patients aged 65-74 years, older patients had more high grade tumors (P = .04), received chemotherapy less often (P < .0001), developed different patterns of recurrence (P < .05), and exhibited a shorter median survival (70 months; P = .05). CONCLUSIONS: Properly selected elderly patients can safely undergo extensive STS resections. Until more effective therapies become available, surgery in the elderly is indicated and remains the best means for STS control.


Assuntos
Sarcoma/cirurgia , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Feminino , Humanos , Masculino , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Sarcoma/patologia , Taxa de Sobrevida , Resultado do Tratamento
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