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1.
Proc Natl Acad Sci U S A ; 119(22): e2204402119, 2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35613049

RESUMO

Transcriptional regulation of differentiation is critical for parasitic pathogens to adapt to environmental changes and regulate transmission. In response to encystation stimuli, Giardia lamblia shifts the distribution of the cell cycle toward G2 and induces the expression of cyst wall proteins (CWPs) within 2 to 4 h, indicating that key regulatory steps occur within the first 4 h of encystation. However, the role of transcription factors (TFs) in encystation has primarily been investigated at later time points. How TFs initiate encystation and link it to the cell cycle remains enigmatic. Here, we systematically screened six putative early up-regulated TFs for nuclear localization, established their dynamic expression profiles, and determined their functional role in regulating encystation. We found a critical repressor, Golden2, ARR-B, Psr-1­like protein 1 (GARP)­like protein 4 (GLP4), that increases rapidly after 30 min of encystation stimuli and down-regulates encystation-specific markers, including CWPs and enzymes in the cyst N-acetylgalactosamine pathway. Depletion of GLP4 increases cyst production. Importantly, we observe that G2+M cells exhibit higher levels of CWP1, resulting from the activation of myeloblastosis domain protein 2 (MYB2), a TF previously linked to encystation in Giardia. GLP4 up-regulation occurs in G1+S cells, suggesting a role in repressing MYB2 and encystation-specific genes in the G1+S phase of the cell cycle. Furthermore, we demonstrate that depletion of GLP4 up-regulates MYB2 and promotes encystation while overexpression of GLP4 down-regulates MYB2 and represses encystation. Together, these results suggest that Giardia employs a dose-dependent transcriptional response that involves the cell-cycle­regulated repressor GLP4 to orchestrate MYB2 and entry into the encystation pathway.


Assuntos
Giardia lamblia , Encistamento de Parasitas , Proteínas de Protozoários , Proteínas Repressoras , Transativadores , Ciclo Celular/genética , Diferenciação Celular/genética , Giardia lamblia/genética , Giardia lamblia/metabolismo , Encistamento de Parasitas/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transativadores/genética
2.
PLoS Pathog ; 18(4): e1010496, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35482847

RESUMO

Attachment to the intestinal epithelium is critical to the lifestyle of the ubiquitous parasite Giardia lamblia. The ventrolateral flange is a sheet-like membrane protrusion at the interface between parasites and attached surfaces. This structure has been implicated in attachment, but its role has been poorly defined. Here, we identified a novel actin associated protein with putative WH2-like actin binding domains we named Flangin. Flangin complexes with Giardia actin (GlActin) and is enriched in the ventrolateral flange making it a valuable marker for studying the flanges' role in Giardia biology. Live imaging revealed that the flange grows to around 1 µm in width after cytokinesis, then remains uniform in size during interphase, grows in mitosis, and is resorbed during cytokinesis. A flangin truncation mutant stabilizes the flange and blocks cytokinesis, indicating that flange disassembly is necessary for rapid myosin-independent cytokinesis in Giardia. Rho family GTPases are important regulators of membrane protrusions and GlRac, the sole Rho family GTPase in Giardia, was localized to the flange. Knockdown of Flangin, GlActin, and GlRac result in flange formation defects. This indicates a conserved role for GlRac and GlActin in forming membrane protrusions, despite the absence of canonical actin binding proteins that link Rho GTPase signaling to lamellipodia formation. Flangin-depleted parasites had reduced surface contact and when challenged with fluid shear force in flow chambers they had a reduced ability to remain attached, confirming a role for the flange in attachment. This secondary attachment mechanism complements the microtubule based adhesive ventral disc, a feature that may be particularly important during mitosis when the parental ventral disc disassembles in preparation for cytokinesis. This work supports the emerging view that Giardia's unconventional actin cytoskeleton has an important role in supporting parasite attachment.


Assuntos
Giardia lamblia , Giardíase , Parasitos , Actinas/metabolismo , Animais , Giardia/metabolismo , Giardia lamblia/genética , Giardia lamblia/metabolismo , Giardíase/parasitologia , Parasitos/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
3.
J Pathol ; 252(2): 201-214, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32686114

RESUMO

Endometrial carcinoma, the most common gynaecological cancer, develops from endometrial epithelium which is composed of secretory and ciliated cells. Pathologic classification is unreliable and there is a need for prognostic tools. We used single cell sequencing to study organoid model systems derived from normal endometrial endometrium to discover novel markers specific for endometrial ciliated or secretory cells. A marker of secretory cells (MPST) and several markers of ciliated cells (FAM92B, WDR16, and DYDC2) were validated by immunohistochemistry on organoids and tissue sections. We performed single cell sequencing on endometrial and ovarian tumours and found both secretory-like and ciliated-like tumour cells. We found that ciliated cell markers (DYDC2, CTH, FOXJ1, and p73) and the secretory cell marker MPST were expressed in endometrial tumours and positively correlated with disease-specific and overall survival of endometrial cancer patients. These findings suggest that expression of differentiation markers in tumours correlates with less aggressive disease, as would be expected for tumours that retain differentiation capacity, albeit cryptic in the case of ciliated cells. These markers could be used to improve the risk stratification of endometrial cancer patients, thereby improving their management. We further assessed whether consideration of MPST expression could refine the ProMiSE molecular classification system for endometrial tumours. We found that higher expression levels of MPST could be used to refine stratification of three of the four ProMiSE molecular subgroups, and that any level of MPST expression was able to significantly refine risk stratification of the copy number high subgroup which has the worst prognosis. Taken together, this shows that single cell sequencing of putative cells of origin has the potential to uncover novel biomarkers that could be used to guide management of cancers. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma Endometrioide/patologia , Neoplasias do Endométrio/patologia , Análise de Sequência de RNA/métodos , Diferenciação Celular , Feminino , Humanos , Organoides , Transcriptoma
4.
Proc Natl Acad Sci U S A ; 114(29): E5854-E5863, 2017 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-28679631

RESUMO

Devoid of all known canonical actin-binding proteins, the prevalent parasite Giardia lamblia uses an alternative mechanism for cytokinesis. Unique aspects of this mechanism can potentially be leveraged for therapeutic development. Here, live-cell imaging methods were developed for Giardia to establish division kinetics and the core division machinery. Surprisingly, Giardia cytokinesis occurred with a median time that is ∼60 times faster than mammalian cells. In contrast to cells that use a contractile ring, actin was not concentrated in the furrow and was not directly required for furrow progression. Live-cell imaging and morpholino depletion of axonemal Paralyzed Flagella 16 indicated that flagella-based forces initiated daughter cell separation and provided a source for membrane tension. Inhibition of membrane partitioning blocked furrow progression, indicating a requirement for membrane trafficking to support furrow advancement. Rab11 was found to load onto the intracytoplasmic axonemes late in mitosis and to accumulate near the ends of nascent axonemes. These developing axonemes were positioned to coordinate trafficking into the furrow and mark the center of the cell in lieu of a midbody/phragmoplast. We show that flagella motility, Rab11, and actin coordination are necessary for proper abscission. Organisms representing three of the five eukaryotic supergroups lack myosin II of the actomyosin contractile ring. These results support an emerging view that flagella play a central role in cell division among protists that lack myosin II and additionally implicate the broad use of membrane tension as a mechanism to drive abscission.


Assuntos
Membrana Celular/metabolismo , Flagelos/metabolismo , Giardia lamblia/citologia , Miosinas/metabolismo , Actinas/metabolismo , Brefeldina A/farmacologia , Membrana Celular/efeitos dos fármacos , Citocinese/fisiologia , Técnicas de Silenciamento de Genes , Giardia lamblia/efeitos dos fármacos , Giardia lamblia/genética , Giardia lamblia/metabolismo , Mitose , Miosinas/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tubulina (Proteína)/metabolismo , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismo
5.
Plant Physiol ; 176(1): 270-281, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28956755

RESUMO

Isolated nuclei provide access to early steps in gene regulation involving chromatin as well as transcript production and processing. Here, we describe transfer of the isolation of nuclei from tagged specific cell types (INTACT) to the monocot rice (Oryza sativa L.). The purification of biotinylated nuclei was redesigned by replacing the outer nuclear-envelope-targeting domain of the nuclear tagging fusion (NTF) protein with an outer nuclear-envelope-anchored domain. This modified NTF was combined with codon-optimized Escherichia coli BirA in a single T-DNA construct. We also developed inexpensive methods for INTACT, T-DNA insertion mapping, and profiling of the complete nuclear transcriptome, including a ribosomal RNA degradation procedure that minimizes pre-ribosomal RNA (pre-rRNA) transcripts. A high-resolution comparison of nuclear and steady-state poly(A)+ transcript populations of seedling root tips confirmed the capture of pre-messenger RNA (pre-mRNA) and exposed distinctions in diversity and abundance of the nuclear and total transcriptomes. This retooled INTACT can enable high-resolution monitoring of the nuclear transcriptome and chromatin in specific cell types of rice and other species.


Assuntos
Núcleo Celular/genética , Técnicas Citológicas/métodos , Transcriptoma/genética , Biotinilação , Proteínas de Fluorescência Verde/metabolismo , Meristema/metabolismo , Membrana Nuclear/metabolismo , Oryza/genética , Plantas Geneticamente Modificadas , Domínios Proteicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo
6.
Int J Obes (Lond) ; 42(2): 198-204, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28816228

RESUMO

BACKGROUND/OBJECTIVES: Telomere shortening is associated with age and risk of medical comorbidity. We assessed the relationship between measures of adiposity, leukocyte telomere length, and mortality and whether it is modified by age. SUBJECTS/METHODS: Subjects with dual-energy X-ray absorptiometry measures were identified using the National Health and Nutrition Examination Survey 1999-2002. Obesity was categorized using two body fat definitions (BF1%: men ⩾25%; females ⩾35%; BF2% ⩾28% and ⩾38%, respectively), body mass index (BMI) and waist circumference (WC; men ⩾102 cm; females ⩾88 cm). Telomere length relative to standard reference DNA (T/S ratio) was assessed using quantitative PCR. Weighted multivariable regression models evaluated the association of telomere length with adiposity, both continuously and categorically (low/normal BF%, low/high WC and standard BMI categories). Differences in telomere length by age and adiposity were ascertained and subsequent models were stratified by age. Proportional hazard models assessed the risk of mortality by adiposity status. A telomere by adiposity interaction was tested in the entire cohort and by age category (<60 vs ⩾60 years; <70 vs ⩾70 years). RESULTS: We identified 7827 subjects. Mean age was 46.1 years. Overall telomere length was 1.05±0.01 (s.e.) that differed by BF1% (low/high: 1.12±0.02 vs 1.03±0.02; P<0.001), BF2% (1.02±0.02 vs 1.11±0.02; P<0.001), BMI (underweight 1.08±0.03; normal 1.09±0.02; overweight 1.04±0.02; and obese 1.03±0.02;P<0.001) and WC (low/high 1.09±0.02 vs 1.02±0.02; P<0.001). Adjusted ß-coefficients evaluating the relationship between telomere length and adiposity (measured continuously) were as follows: BF1% (ß=-0.0033±0.0008; P<0.001), BF2% (-0.041±0.008; P<0.001), BMI (ß=-0.025±0.0008; P=0.005) and WC (ß=-0.0011±0.0004; P=0.007). High BF% (BF1%: ß=-0.035±0.011; P=0.002; BF2%: ß=-0.041±0.008; P<0.001) and WC (ß=-0.035±0.011; P=0.008) were inversely related to telomere length (TL). Stratifying by age, high BF1% (-0.061±0.013), BF2% (-0.065±0.01), BMI-obesity (-0.07±0.015) and high WC (-0.048±0.013) were significant (all P<0.001). This association diminished with increasing age. In older participants, TL was inversely related to mortality (hazard ratio 0.36 (0.27, 0.49)), as were those classified by BF1% (0.68 (0.56, 0.81)), BF2% (0.75 (0.65, 0.80)), BMI (0.50 (0.42, 0.60)) and WC (0.72 (0.63, 0.83)). No interaction was observed between adiposity status, telomere length and mortality. CONCLUSIONS: Obesity is associated with shorter telomere length in young participants, a relationship that diminishes with increasing age. It does not moderate the relationship with mortality.


Assuntos
Adiposidade/genética , Adiposidade/fisiologia , Inquéritos Nutricionais , Obesidade/mortalidade , Encurtamento do Telômero/fisiologia , Absorciometria de Fóton , Idoso , Composição Corporal , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/genética , Obesidade/fisiopatologia , Modelos de Riscos Proporcionais , Telômero
7.
Rev Epidemiol Sante Publique ; 66(5): 301-309, 2018 Sep.
Artigo em Francês | MEDLINE | ID: mdl-30181005

RESUMO

BACKGROUND: Constipation is a frequent issue during hospitalization. Multiple causes such as the existence of irregular habits, lack of exercise as well as medical history have been identified. Drugs such as strong painkillers, central nervous system therapies and treatments of the digestive tract are a major cause of constipation. Additionally, unbalanced diet, fluid deficiency, and anxiety may aggravate constipation. The consideration of all these risk factors being under the responsibility of nurses. The difficulty to take into account such a multifactorial aetiology in nursing practice and the fact that there is no easy to use and validated tool to assess the risk of constipation in current nurse practice has led us to consider the development of a Risk Assessment scale of Constipation in Patient Hospitalized (ERCoPH) to facilitate preventive management of this trouble. We present here the first step of the elaboration of this scale, the identification of risk factors through a consensus approach after a systematic literature review. METHODS: The key informants consensus-based approach proposed by Pineault and Daveluy is based on five steps: (1) a literature review to identify risk factors for constipation; (2) the elaboration of a questionnaire containing the factors identified in the first step; (3) pre-select a panel of experts; (4) submission the questionnaire to the panel; (5) analysis the results of the consensus survey. Only factors that received a rating>6 by at least 80 % of the experts were retained. RESULTS: The systematic literature review identified 69 risk factors submitted to the 23 experts of the panel. Fifteen risk factors were retained after analyzing the answers of the experts. The Scientific Committee added eight risk factors because of their importance in the literature and decided to group together some factors of the same domain. CONCLUSION: A total of 19 risk factors were selected and grouped by major class (age, physical activity, medication, social data, food/hydration, medical and surgical history and environmental data). These factors have been tested among 300 patients enrolled in different clinical settings as part of the construction and validation of ERCoPH.


Assuntos
Consenso , Constipação Intestinal/etiologia , Constipação Intestinal/enfermagem , Constipação Intestinal/epidemiologia , Projetos de Pesquisa Epidemiológica , Prova Pericial , Hospitalização/estatística & dados numéricos , Humanos , Padrões de Prática em Enfermagem/normas , Padrões de Prática em Enfermagem/estatística & dados numéricos , Fatores de Risco
8.
Br J Surg ; 104(3): 205-213, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27779312

RESUMO

BACKGROUND: Open studies have reported favourable results for sacral nerve stimulation in the treatment of refractory constipation. Here, its efficacy was assessed in a double-blind crossover RCT. METHODS: Patients with at least two of the following criteria were included: fewer than three bowel movements per week; straining to evacuate on more than 25 per cent of attempts; or sensation of incomplete evacuation on more than 25 per cent of occasions. Response to therapy was defined as at least three bowel movements per week and/or more than 50 per cent improvement in symptoms. Responders to an initial 3-week peripheral nerve evaluation were offered permanent implantation of a pulse generator and were assigned randomly in a crossover design to two 8-week intervals of active or sham stimulation. At the end of the two trial periods, the patients received active stimulation until the final evaluation at 1 year. RESULTS: Thirty-six patients (34 women; mean(s.d.) age 45(14) years) underwent peripheral nerve evaluation. Twenty responded and received a permanent stimulator. A positive response was observed in 12 of 20 and 11 of 20 patients after active and sham stimulation periods respectively (P = 0·746). Pain related to the device occurred in five patients and wound infection or haematoma in three, leading to definitive removal of the pulse generator in two patients. At 1 year, 11 of the 20 patients with an implanted device continued to respond. Stimulation had no significant effect on colonic transit time. CONCLUSION: These results do not support the recommendation of permanent implantation of a pulse generator in patients with refractory constipation who initially responded to temporary nerve stimulation. Registration number: NCT01629303 (http://www.clinicaltrials.gov).


Assuntos
Constipação Intestinal/terapia , Terapia por Estimulação Elétrica/métodos , Plexo Lombossacral , Adolescente , Adulto , Idoso , Estudos Cross-Over , Método Duplo-Cego , Terapia por Estimulação Elétrica/instrumentação , Feminino , Seguimentos , Humanos , Neuroestimuladores Implantáveis , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto Jovem
9.
bioRxiv ; 2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-37090513

RESUMO

Protozoan parasites use cAMP signaling to precisely regulate the place and time of developmental differentiation, yet it is unclear how this signaling is initiated. Encystation of the intestinal parasite Giardia lamblia can be activated by multiple stimuli, which we hypothesize result in a common physiological change. We demonstrate that bile alters plasma membrane fluidity by reducing cholesterol-rich lipid microdomains, while alkaline pH enhances bile function. Through depletion of the cAMP producing enzyme Adenylate Cyclase 2 (AC2) and the use of a newly developed Giardia-specific cAMP sensor, we show that AC2 is necessary for encystation stimuli-induced cAMP upregulation and activation of downstream signaling. Conversely, over expression of AC2 or exogenous cAMP were sufficient to initiate encystation. Our findings indicate that encystation stimuli induce membrane reorganization, trigger AC2-dependent cAMP upregulation, and initiate encystation-specific gene expression, thereby advancing our understanding of a critical stage in the life cycle of a globally important parasite.

10.
Nat Commun ; 14(1): 7245, 2023 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-37945557

RESUMO

Protozoan parasites use cAMP signaling to precisely regulate the place and time of developmental differentiation, yet it is unclear how this signaling is initiated. Encystation of the intestinal parasite Giardia lamblia can be activated by multiple stimuli, which we hypothesize result in a common physiological change. We demonstrate that bile alters plasma membrane fluidity by reducing cholesterol-rich lipid microdomains, while alkaline pH enhances bile function. Through depletion of the cAMP producing enzyme Adenylate Cyclase 2 (AC2) and the use of a newly developed Giardia-specific cAMP sensor, we show that AC2 is necessary for encystation stimuli-induced cAMP upregulation and activation of downstream signaling. Conversely, over expression of AC2 or exogenous cAMP were sufficient to initiate encystation. Our findings indicate that encystation stimuli induce membrane reorganization, trigger AC2-dependent cAMP upregulation, and initiate encystation-specific gene expression, thereby advancing our understanding of a critical stage in the life cycle of a globally important parasite.


Assuntos
Giardia lamblia , Giardíase , Humanos , Giardia , Adenilil Ciclases/genética , Adenilil Ciclases/metabolismo , Giardíase/parasitologia , Giardia lamblia/genética , Giardia lamblia/metabolismo , Ativação Transcricional , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
11.
Res Sq ; 2023 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-37162830

RESUMO

Protozoan parasites use cAMP signaling to precisely regulate the place and time of developmental differentiation, yet it is unclear how this signaling is initiated. Encystation of the intestinal parasite Giardia lamblia can be activated by multiple stimuli, which we hypothesize result in a common physiological change. We demonstrate that bile alters plasma membrane fluidity by reducing cholesterol-rich lipid microdomains, while alkaline pH enhances bile function. Through depletion of the cAMP producing enzyme Adenylate Cyclase 2 (AC2) and the use of a newly developed Giardia-specific cAMP sensor, we show that AC2 is necessary for encystation stimuli-induced cAMP upregulation and activation of downstream signaling. Conversely, over expression of AC2 or exogenous cAMP were sufficient to initiate encystation. Our findings indicate that encystation stimuli induce membrane reorganization, trigger AC2-dependent cAMP upregulation, and initiate encystation-specific gene expression, thereby advancing our understanding of a critical stage in the life cycle of a globally important parasite.

12.
Br J Anaesth ; 108(6): 1022-7, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22466821

RESUMO

BACKGROUND: It is no longer safe to use large tidal volumes (V(T)) (>8 ml kg(-1)) for one-lung ventilation (OLV), and limiting plateau pressure should be a major objective. Due to the specificity of OLV, the use of positive end-expiratory pressure (PEEP) remains controversial. This study determined whether at the same low plateau pressure, reducing V(T) and increasing PEEP were not inferior to larger V(T) and lower PEEP ventilation in terms of oxygenation. METHODS: This prospective, randomized, non-inferiority, cross-over trial included 88 patients undergoing open thoracotomy who received two successive ventilatory strategies in random order: V(T) (8 ml kg(-1) of ideal body weight) with low PEEP (5 cm H(2)O), or low V(T) (5 ml kg(-1)) with a high PEEP. Respiratory rate and PEEP were, respectively, adjusted to maintain constant ventilation and plateau pressure. The primary endpoint was the ratio under each ventilatory strategy. RESULTS: The non-inferiority of low-V(T) ventilation could not be established. The mean adjusted ratio was lower overall during low-V(T) ventilation, and differences between the two ventilatory modes varied significantly according to baseline (T0). Decreased oxygenation during low V(T) was smaller when baseline values were low. Systolic arterial pressure was not lower during low-V(T) ventilation. CONCLUSION: During OLV, lowering V(T) and increasing PEEP, with the same low plateau pressure, reduced oxygenation compared with larger V(T) and lower PEEP. This strategy may reduce the risk of lung injury, but needs to be investigated further.


Assuntos
Oxigênio/metabolismo , Respiração com Pressão Positiva , Respiração Artificial , Volume de Ventilação Pulmonar , Idoso , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
13.
Dev Cell ; 57(9): 1177-1192.e6, 2022 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-35504287

RESUMO

Understanding how roots modulate development under varied irrigation or rainfall is crucial for development of climate-resilient crops. We established a toolbox of tagged rice lines to profile translating mRNAs and chromatin accessibility within specific cell populations. We used these to study roots in a range of environments: plates in the lab, controlled greenhouse stress and recovery conditions, and outdoors in a paddy. Integration of chromatin and mRNA data resolves regulatory networks of the following: cycle genes in proliferating cells that attenuate DNA synthesis under submergence; genes involved in auxin signaling, the circadian clock, and small RNA regulation in ground tissue; and suberin biosynthesis, iron transporters, and nitrogen assimilation in endodermal/exodermal cells modulated with water availability. By applying a systems approach, we identify known and candidate driver transcription factors of water-deficit responses and xylem development plasticity. Collectively, this resource will facilitate genetic improvements in root systems for optimal climate resilience.


Assuntos
Oryza , Cromatina/metabolismo , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Água/metabolismo
14.
Front Cell Dev Biol ; 9: 662945, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33987184

RESUMO

Differentiation into environmentally resistant cysts is required for transmission of the ubiquitous intestinal parasite Giardia lamblia. Encystation in Giardia requires the production, processing and transport of Cyst Wall Proteins (CWPs) in developmentally induced, Golgi-like, Encystation Specific Vesicles (ESVs). Progress through this trafficking pathway can be followed by tracking CWP localization over time. However, there is no recognized system to distinguish the advancing stages of this process which can complete at variable rates depending on how encystation is induced. Here, we propose a staging system for encysting Giardia based on the morphology of CWP1-stained ESVs. We demonstrate the molecular distinctiveness of maturing ESVs at these stages by following GlRab GTPases through encystation. Previously, we established that Giardia's sole Rho family GTPase, GlRac, associates with ESVs and has a role in regulating their maturation and the secretion of their cargo. As a proof of principle, we delineate the relationship between GlRac and ESV stages. Through proteomic studies, we identify putative interactors of GlRac that could be used as additional ESV stage markers. This staging system provides a common descriptor of ESV maturation regardless of the source of encysting cells. Furthermore, the identified set of molecular markers for ESV stages will be a powerful tool for characterizing trafficking mutants that impair ESV maturation and morphology.

15.
J Vet Intern Med ; 24(4): 809-18, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20561188

RESUMO

BACKGROUND: Reference intervals (RI) are pivotal in clinical pathology. The influence of breed on RI has been poorly documented in cats. HYPOTHESIS/OBJECTIVES: RI for plasma biochemistry variables are breed-dependent in cats. ANIMALS: Five hundred and thirty-six clinically healthy, fasted, client-owned cats from 4 breeds: Holly Birman (n=132), Chartreux (n=129), Maine Coon (n=139), and Persian (n=136). METHODS: Prospective observational study: Blood samples were collected from the cephalic vein into capillary tubes containing lithium heparin. Plasma glucose, urea, creatinine, total proteins, albumin, calcium, phosphate, sodium, potassium, chloride, and total CO2 concentrations and the activities of alanine aminotransferase and alkaline phosphatase were assayed with a dry slide biochemical analyzer. RI were defined as central 95% intervals bounded by the 2.5th and 97.5th percentiles. Data were analyzed by a linear mixed effects model with type I error rate of 0.05. RESULTS: A significant (P<.05) breed effect was observed for 9/13 variables. The magnitude of the differences between breeds could be clinically relevant for creatinine, glucose, and total protein. Age, body weight, sex, and housing conditions had significant (P<.05) breed-related effects on different variables. CONCLUSIONS AND CLINICAL IMPORTANCE: Breed-specific RI should be considered for cats.


Assuntos
Análise Química do Sangue/veterinária , Gatos/sangue , Gatos/genética , Animais , Feminino , Masculino , Valores de Referência
16.
Mol Biol Cell ; 31(15): 1611-1622, 2020 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-32459558

RESUMO

Giardia has 198 Nek kinases whereas humans have only 11. Giardia has a complex microtubule cytoskeleton that includes eight flagella and several unique microtubule arrays that are utilized for parasite attachment and facilitation of rapid mitosis and cytokinesis. The need to regulate these structures may explain the parallel expansion of the number of Nek family kinases. Here we use live and fixed cell imaging to uncover the role of Nek8445 in regulating Giardia cell division. We demonstrate that Nek8445 localization is cell cycle regulated and this kinase has a role in regulating overall microtubule organization. Nek8445 depletion results in short flagella, aberrant ventral disk organization, loss of the funis, defective axoneme exit, and altered cell shape. The axoneme exit defect is specific to the caudal axonemes, which exit from the posterior of the cell, and this defect correlates with rounding of the cell posterior and loss of the funis. Our findings implicate a role for the funis in establishing Giardia's cell shape and guiding axoneme docking. On a broader scale our results support the emerging view that Nek family kinases have a general role in regulating microtubule organization.


Assuntos
Citocinese , Giardia lamblia/citologia , Giardia lamblia/enzimologia , Microtúbulos/metabolismo , Proteínas Quinases/metabolismo , Proteínas de Protozoários/metabolismo , Axonema/metabolismo , Axonema/ultraestrutura , Flagelos/metabolismo
17.
Encephale ; 35(5): 496-8, 2009 Oct.
Artigo em Francês | MEDLINE | ID: mdl-19853725

RESUMO

INTRODUCTION: Aripiprazole is an atypical antipsychotic with a pharmacological profile, different from other atypical antipsychotics. It is a high-affinity partial agonist at the dopamine D2 and serotonin 5-HT1A receptors and an antagonist at serotonin 5-HT2 receptors. It is associated with a good safety and tolerability profile including extrapyramidal side-effects. CASE-REPORT: We report on a 37 year-old female patient with paranoid schizophrenia who developed Parkinsonian symptoms after one month of aripiprazole 10mg per day. She had been admitted to our unit for a psychotic episode with delusions of persecution and grandiosity. It was her second hospitalization. During the first hospitalization, seven years earlier, she had been treated with haloperidol. We do not have any information about the tolerability of that treatment. At the start, she received olanzapine with good tolerability but without efficacy on psychotic symptoms. After 4 weeks, we switched from olanzapine to risperidone 6 mg per day. After a few days, the patient developed severe Parkinsonian symptoms. We reduced the dose to 4 mg per day without any effect on the extrapyramidal symptoms.We decided to discontinue risperidone and to introduce aripiprazole 10mg per day. After one month, the patient developed severe Parkinsonian symptoms including hypertonia, akinesia, and shuffling gait. After reduction of the dose of Aripiprazole to 5mg per day, all the Parkinsonian symptoms had disappeared within 5 days without any other medication. DISCUSSION: Few reports of Parkinsonian symptoms with aripiprazole have been published in the adult population. There is one report of Parkinsonian symptoms, associated with hypersalivation without akathisia, in a patient treated with 30 mg per day of aripiprazole. All the symptoms disappeared after a switch to olanzapine. The other cases have been reported when aripiprazole was associated with anti-depressant serotonin specific reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors. One report has been published of a 16 year-old girl who had already developed extrapyramidal symptoms with olanzapine and risperidone. Another has been published concerning a 3 year-old child who had taken a half tablet of aripiprazole 15 mg. CONCLUSION: We hypothesise that cytochrome P450 2D6 is implicated in this case-report because it is active in metabolizing aripiprazole. This patient could have been deficient in this enzyme, thus failing to metabolize aripiprazole at a normal rate.


Assuntos
Antipsicóticos/efeitos adversos , Transtornos Parkinsonianos/induzido quimicamente , Piperazinas/efeitos adversos , Quinolonas/efeitos adversos , Esquizofrenia Paranoide/tratamento farmacológico , Adulto , Antipsicóticos/uso terapêutico , Aripiprazol , Relação Dose-Resposta a Droga , Feminino , Humanos , Transtornos Parkinsonianos/diagnóstico , Piperazinas/uso terapêutico , Quinolonas/uso terapêutico , Esquizofrenia Paranoide/psicologia
18.
Res Vet Sci ; 84(3): 354-60, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17826812

RESUMO

The APOLOWAKO is an entirely automatic benchtop biochemistry analyzer that uses stabilized liquid reagents. It was tested for canine blood and plasma glucose, creatinine, urea, total proteins, alanine aminotransferase, and alkaline phosphatase. The APOLOWAKO gave very similar results for whole blood and the corresponding plasma (n=32). Within-laboratory imprecision was below 2.2% and 5.8% for substrates and enzymes, respectively. Comparison of results with whole blood by APOLOWAKO and with the corresponding plasma by Vitros 250 (n=139) showed very good correlations. Passing-Bablok's regression slopes ranged from 0.83 to 1.12 and intercepts were close to zero, except for ALP where the results obtained by APOLOWAKO were approximately 1.5 times higher than by Vitros. The APOLOWAKO system can be a reliable instrument in veterinary practices where larger systems are not available but it should be further validated and reference intervals should be determined.


Assuntos
Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Autoanálise/métodos , Glicemia/análise , Proteínas Sanguíneas/análise , Creatinina/sangue , Ureia/sangue , Animais , Autoanálise/instrumentação , Cães , Reprodutibilidade dos Testes
19.
J Gynecol Obstet Biol Reprod (Paris) ; 37(7): 705-13, 2008 Nov.
Artigo em Francês | MEDLINE | ID: mdl-18722063

RESUMO

OBJECTIVE: Describe and define the factors associated with missed opportunities of an in utero transfer (IUT), defined by by an absence of IUT where there was no counter-indication for a transfer. MATERIALS AND METHODS: Multicentric and retrospective cohort study within the Aquitaine perinatal healthcare network from 1st January 2003 to 30th June 2005 on deliveries between 24 and 32 weeks gestation, depending on whether the woman initially followed care in level I or II facilities benefited from an IUT at a level III facility or not. associated with missed opportunities of IUT were analysed by a logistic regression. RESULTS: Five hundred and twelve deliveries, eligible to deliver in level III facilities, were included in the study: 273 after an IUT and 239 in a level I or II maternity hospitals out of which 18% are defined as a missed opportunity of an in utero transfer. The multivariate analysis did not show a link between missed opportunities of an in utero transfer and the characteristics of maternities: status, size, level of care and distance from a level III facility. Only the delivery term appears to be linked to a missed opportunity of an in utero transfer (p=0.01): 32 weeks gestation versus 26-29 weeks gestation (RC=6.53; IC(95%): 2.00-21.25). While managing the delivery after 31 weeks gestation is considered suitable in a level IIb facility, the delivery term is no longer statistically related to a missed opportunity. CONCLUSION: This study serves as a first analysis of the Aquitaine perinatal healthcare network. It shows that missed opportunities of IUT does not seem to be linked to characteristics of maternities but seems to be linked to deliveries after 31 weeks gestation in level IIb facilities.


Assuntos
Recém-Nascido Prematuro , Transferência de Pacientes , Feminino , França , Idade Gestacional , Humanos , Recém-Nascido , Modelos Logísticos , Trabalho de Parto Prematuro , Gravidez , Estudos Retrospectivos
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