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1.
Nat Commun ; 12(1): 1273, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627667

RESUMO

Multicilia are delicate motile machineries, and how they are accurately assembled is poorly understood. Here, we show that fibrogranular materials (FGMs), large arrays of electron-dense granules specific to multiciliated cells, are essential for their ultrastructural fidelity. Pcm1 forms the granular units that further network into widespread FGMs, which are abundant in spherical FGM cores. FGM cores selectively concentrate multiple important centriole-related proteins as clients, including Cep131 that specifically decorates a foot region of ciliary central pair (CP) microtubules. FGMs also tightly contact deuterosome-procentriole complexes. Disruption of FGMs in mouse cells undergoing multiciliogenesis by Pcm1 RNAi markedly deregulates centriolar targeting of FGM clients, elongates CP-foot, and alters deuterosome size, number, and distribution. Although the multicilia are produced in correct numbers, they display abnormal ultrastructure and motility. Our results suggest that FGMs organize deuterosomes and centriole-related proteins to facilitate the faithful assembly of basal bodies and multiciliary axonemes.

2.
PLoS Genet ; 16(12): e1009232, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33347437

RESUMO

Motile cilia can beat with distinct patterns, but how motility variations are regulated remain obscure. Here, we have studied the role of the coiled-coil protein CFAP53 in the motility of different cilia-types in the mouse. While node (9+0) cilia of Cfap53 mutants were immotile, tracheal and ependymal (9+2) cilia retained motility, albeit with an altered beat pattern. In node cilia, CFAP53 mainly localized at the base (centriolar satellites), whereas it was also present along the entire axoneme in tracheal cilia. CFAP53 associated tightly with microtubules and interacted with axonemal dyneins and TTC25, a dynein docking complex component. TTC25 and outer dynein arms (ODAs) were lost from node cilia, but were largely maintained in tracheal cilia of Cfap53-/- mice. Thus, CFAP53 at the base of node cilia facilitates axonemal transport of TTC25 and dyneins, while axonemal CFAP53 in 9+2 cilia stabilizes dynein binding to microtubules. Our study establishes how differential localization and function of CFAP53 contributes to the unique motion patterns of two important mammalian cilia-types.

3.
EMBO J ; : e105499, 2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33241915

RESUMO

Cilia of higher animals sense various environmental stimuli. Proper ciliary signaling requires appropriate extent of BBSome-mediated export of membrane receptors across ciliary barrier transition zone (TZ) through retrograde intraflagellar transport (IFT) machinery. How the barrier passage is controlled, however, remains unknown. Here, we show that small GTPase Rabl2 functions as a molecular switch for the outward TZ passage. Rabl2-GTP enters cilia by binding to IFT-B complex. Its GTP hydrolysis enables the outward TZ passage of the BBSome and its cargos with retrograde IFT machinery, whereas its persistent association leads to their shedding from IFT-B during the passing process and consequently ciliary retention. Rabl2 deficiency or expression of a GTP-locked mutant impairs the ciliary hedgehog signaling without interfering with ciliation and respectively results in different spectrums of mouse developmental disorders. We propose that the switch role of Rabl2 ensures proper turnover of the BBSome and ciliary membrane receptors to fine-tune cilia-dependent signaling for normal embryonic development and organismic homeostasis.

4.
Braz J Med Biol Res ; 53(11): e9266, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33053114

RESUMO

The etiology of polycystic ovary syndrome (PCOS) is complex and the pathogenesis is not fully understood. Some studies have shown that dysregulation of ovarian granulosa cells may be related to abnormal follicles and excessive androgen in women with PCOS. Our team has also confirmed the high expression status of H19 in PCOS patients in the early stage. However, the relationship between H19 and miR-19b in the development of PCOS is still unknown. Therefore, we used bioinformatics to predict the binding sites of human H19 and miR-19b, and of miR-19b and CTGF genes. After the silencing and overexpression of H19, real-time polymerase chain reaction (PCR) was used to detect the expressions of H19, miR-19b, and CTGF. Western blotting was used to detect CTGF protein. Proliferation of KGN cells after H19 silencing was detected by CCK8. Flow cytometry was used to detect the apoptosis of KGN cells after H19 silencing. After the overexpression of H19, it was found that the expression of miR-19b gene decreased and the expression of CTGF increased, whereas silencing of H19 did the opposite. In addition, H19 could promote cell proliferation and decrease cell apoptosis. Finally, luciferase reporter assays showed that the 3'-end sequences of lncRNA H19 and CTGF contained the binding site of miR-19b. In conclusion, our study indicated that lncRNA H19 acted as a ceRNA to bind to miR-19b via a "sponge" to regulate the effect of CTGF on KGN cells, which may play a vital role in PCOS.


Assuntos
Síndrome do Ovário Policístico , Apoptose , Proliferação de Células , Fator de Crescimento do Tecido Conjuntivo , Feminino , Humanos , MicroRNAs/genética , Síndrome do Ovário Policístico/genética , RNA Longo não Codificante/genética
5.
Ann Hum Biol ; : 1-26, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33050724

RESUMO

Background: Cognitive decline can develop into mild cognitive impairment, a high-risk factor in the progression of Alzheimer's disease. The antioxidant micronutrient selenium may have some effect on preventing cognitive decline, but the association between whole blood selenium concentration and cognitive function remains controversial.Aim: To investigate the association between whole blood selenium concentration and cognitive function score in elderly Americans.Subjects and methods: Data was obtained from the national health and nutrition survey between 2011 and 2014. A general linear model was used to adjust for possible risk factors to analyse the association between blood selenium concentration and cognitive function.Results: 2068 participants were included in our study, and the average blood selenium concentration was high at 195.08µg/L. The risk of lower cognitive scores was higher in people with lower blood selenium concentration (p < 0.05). The lower cognition may also be associated with one or more of the following characteristics: older, male, had a low poverty-income ratio, low education level, and consumed less alcohol. Related conditions such as stroke, diabetes and high blood pressure may also affect cognitive scores.Conclusions: Higher blood selenium is associated with higher cognitive scores in elderly Americans.

6.
PeerJ ; 8: e9519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32742797

RESUMO

The Songnen Plain of China was once an important grassland used for sheep grazing, but it has largely been degraded to bare saline-alkaline land (BSAL). BSAL consists of plant-free areas characterized by high soil pH values (up to 10) and salt and alkali (e.g., Na+ and Ca2+) contents, as well as low soil organic matter and water contents; thus, very few soil faunal species can survive on BSAL. The recovery of degraded ecosystems provides a great opportunity to investigate the reconstruction of belowground soil faunal communities. Collembola are a class of widespread and abundant soil fauna that can colonize this harsh environment. Habitat changes on BSAL promote aboveground revegetation, which greatly facilitates the recovery of Collembola. A soil transfer experiment on the BSAL of the Songnen Plain was conducted to study the effects of habitat and Collembola morphological traits on the recovery process of Collembola. Defaunated and with-fauna soil blocks were transferred among three habitats: BSAL, reclaimed arable land, and naturally revegetated grassland. The recovered Collembola in the transferred soil blocks were compared two, seven, and 12 weeks after the start of the experiment. The results showed that (1) the majority of the Collembola, regardless of their morphological traits, recovered in the defaunated soil blocks within 2 weeks; (2) generalists and habitat-preferring species recovered faster than specialists; (3) the average total abundance, species richness, and community composition of Collembola recovered to the natural levels in 2 weeks; and (4) 12 weeks after replacement, the highest average total abundance and species richness of Collembola were found in the arable land. Our results indicate that the majority of Collembola in this study, regardless of their dispersal type, which is related to their morphological traits, are fast dispersers, and their recovery speeds are mainly affected by habitat preferences. We suggest that the reclamation of BSAL to arable land rather than its natural recovery to grassland aids in the recovery of Collembola in degraded grassland systems.

7.
Biol Cell ; 112(12): 398-408, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32776587

RESUMO

BACKGROUND INFORMATION: Dense multicilia in protozoa and metazoa generate a strong force important for locomotion and extracellular fluid flow. During ciliogenesis, multiciliated cells produce hundreds of centrioles to serve as basal bodies through various pathways including deuterosome-dependent (DD), hyper-activated mother centriole-dependent (MCD) and basal bodydependent (BBD) pathways. The centrosome-free planarian Schmidtea mediterranea is widely used for regeneration studies because its neoblasts are capable of regenerating any body part after injury. However, it is currently unclear how the flatworms generate massive centrioles for multiciliated cells in the pharynx and body epidermis when their cells are initially centriole-free. RESULTS: In this study, we investigate the progress of centriole amplification during the pharynx regeneration. We observe that the planarian pharyngeal epithelial cells generate their centrioles asynchronously through a de novo pathway. Most of the de novo centrioles are formed individually, whereas the remaining ones are assembled in pairs, possibly by sharing a cartwheel, or in small clusters lacking a nucleation center. Further RNAi experiments show that the known key factors of centriole duplication, including Cep152, Plk4 and Sas6, are crucial for the centriole amplification. CONCLUSIONS AND SIGNIFICANCE: Our study demonstrates the distinct process of massive centriole biogenesis in S. mediterranea and helps to understand the diversity of centriole biogenesis during evolution.

9.
J Cell Sci ; 133(13)2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32503940

RESUMO

The Cep63-Cep152 complex located at the mother centriole recruits Plk4 to initiate centriole biogenesis. How the complex is targeted to mother centrioles, however, is unclear. In this study, we show that Cep57 and its paralog, Cep57l1, colocalize with Cep63 and Cep152 at the proximal end of mother centrioles in both cycling cells and multiciliated cells undergoing centriole amplification. Both Cep57 and Cep57l1 bind to the centrosomal targeting region of Cep63. The depletion of both proteins, but not either one, blocks loading of the Cep63-Cep152 complex to mother centrioles and consequently prevents centriole duplication. We propose that Cep57 and Cep57l1 function redundantly to ensure recruitment of the Cep63-Cep152 complex to the mother centrioles for procentriole formation.

10.
Cell Rep ; 31(3): 107526, 2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32320668

RESUMO

Neurons require proper polarization for precise positioning and axon-dendrite formation. Their intrinsic regulators and underlying mechanisms are poorly understood. Here, we show that Wdr47 is a key polarization regulator. Wdr47-deficient newborn mice die of suffocation due to central nervous system defects including axonal tracts agenesis and slowed radial migration. Wdr47 deficiency represses the multipolar-bipolar transition of cortical neurons, reduces neurite tip-directed microtubule dynamics, and causes multi-axon formation. Overexpression of Wdr47 in wild-type neurons inhibits axon specification and neutralizes Taxol-induced neurite overgrowth and axon overproduction. Wdr47 interacts with the Camsap family of microtubule minus-end-binding proteins; associates with microtubules through Camsap3, whose gene disruption also causes multi-axons; and promotes Camsap3 accumulation in neurites of unpolarized neurons. Furthermore, Camsap overexpression rescues the polarization defects of Wdr47-deficient neurons. Our results indicate that Wdr47 facilitates proper neurite remodeling through Camsaps to fine-tune regional microtubule dynamics and organization during early stages of neuronal polarization.

11.
Braz. j. med. biol. res ; 53(11): e9266, 2020. graf
Artigo em Inglês | LILACS-Express | LILACS, Coleciona SUS | ID: biblio-1132491

RESUMO

The etiology of polycystic ovary syndrome (PCOS) is complex and the pathogenesis is not fully understood. Some studies have shown that dysregulation of ovarian granulosa cells may be related to abnormal follicles and excessive androgen in women with PCOS. Our team has also confirmed the high expression status of H19 in PCOS patients in the early stage. However, the relationship between H19 and miR-19b in the development of PCOS is still unknown. Therefore, we used bioinformatics to predict the binding sites of human H19 and miR-19b, and of miR-19b and CTGF genes. After the silencing and overexpression of H19, real-time polymerase chain reaction (PCR) was used to detect the expressions of H19, miR-19b, and CTGF. Western blotting was used to detect CTGF protein. Proliferation of KGN cells after H19 silencing was detected by CCK8. Flow cytometry was used to detect the apoptosis of KGN cells after H19 silencing. After the overexpression of H19, it was found that the expression of miR-19b gene decreased and the expression of CTGF increased, whereas silencing of H19 did the opposite. In addition, H19 could promote cell proliferation and decrease cell apoptosis. Finally, luciferase reporter assays showed that the 3′-end sequences of lncRNA H19 and CTGF contained the binding site of miR-19b. In conclusion, our study indicated that lncRNA H19 acted as a ceRNA to bind to miR-19b via a "sponge" to regulate the effect of CTGF on KGN cells, which may play a vital role in PCOS.

12.
Endocr J ; 66(7): 587-595, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-30982795

RESUMO

Polycystic ovary syndrome (PCOS) represents a serious reproductive and endocrine condition and is associated with high incidence rates. H19 is a compelling long noncoding RNA (lncRNA) which carries out a range of biological functions. However, prior to this study, little was known as to whether there was an association between lncRNA H19 and PCOS. In the current study, we used quantitative real-time polymerase chain reaction (qRT-PCR) to determine lncRNA H19 expression levels in peripheral blood leukocytes from patients with PCOS and compared this data with that derived from normal controls. We also screened data for potential relationships between lncRNA H19 and a range of endocrine variables in PCOS. The expression of lncRNA H19 was significantly higher in cases of PCOS than in controls. Individuals exhibiting higher expression levels of lncRNA H19 were associated with a significantly higher risk of PCOS than those with lower expression levels. Moreover, lncRNA H19 expression was positively correlated with fasting plasma glucose levels; this was the case with both raw data, and after adjustment for age and BMI in the PCOS group. However, lncRNA H19 expression showed no significant correlation with total testosterone or insulin resistance in either PCOS cases or the controls. In conclusion, we demonstrate the first evidence to indicate that lncRNA H19 is associated with PCOS, suggesting that elevated lncRNA H19 levels are a risk factor for PCOS. For susceptible individuals, lncRNA H19 may represent a useful biomarker of the early stages of endocrine and metabolic disorders in PCOS.


Assuntos
Síndrome do Ovário Policístico/genética , RNA Longo não Codificante/genética , Adulto , Grupo com Ancestrais do Continente Asiático/genética , Grupo com Ancestrais do Continente Asiático/estatística & dados numéricos , Estudos de Casos e Controles , China/epidemiologia , Feminino , Expressão Gênica , Predisposição Genética para Doença , Humanos , Projetos Piloto , Síndrome do Ovário Policístico/epidemiologia , Dados Preliminares , Fatores de Risco
13.
EMBO Rep ; 20(4)2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30833343

RESUMO

Mammalian epithelial cells use a pair of parental centrioles and numerous deuterosomes as platforms for efficient basal body production during multiciliogenesis. How deuterosomes form and function, however, remain controversial. They are proposed to arise either spontaneously for massive de novo centriole biogenesis or in a daughter centriole-dependent manner as shuttles to carry away procentrioles assembled at the centriole. Here, we show that both parental centrioles are dispensable for deuterosome formation. In both mouse tracheal epithelial and ependymal cells (mTECs and mEPCs), discrete deuterosomes in the cytoplasm are initially procentriole-free. They emerge at widely dispersed positions in the cytoplasm and then enlarge, concomitant with their increased ability to form procentrioles. More importantly, deuterosomes still form efficiently in mEPCs whose daughter centriole or even both parental centrioles are eliminated through shRNA-mediated depletion or drug inhibition of Plk4, a kinase essential to centriole biogenesis in both cycling cells and multiciliated cells. Therefore, deuterosomes can be assembled autonomously to mediate de novo centriole amplification in multiciliated cells.

14.
J Mol Cell Biol ; 11(1): 67-77, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30535028

RESUMO

Cilia are cellular protrusions containing nine microtubule (MT) doublets and function to propel cell movement or extracellular liquid flow through beating or sense environmental stimuli through signal transductions. Cilia require the central pair (CP) apparatus, consisting of two CP MTs covered with projections of CP proteins, for planar strokes. How the CP MTs of such '9 + 2' cilia are constructed, however, remains unknown. Here we identify Spef1, an evolutionarily conserved microtubule-bundling protein, as a core CP MT regulator in mammalian cilia. Spef1 was selectively expressed in mammalian cells with 9 + 2 cilia and specifically localized along the CP. Its depletion in multiciliated mouse ependymal cells by RNAi completely abolished the CP MTs and markedly attenuated ciliary localizations of CP proteins such as Hydin and Spag6, resulting in rotational beat of the ependymal cilia. Spef1, which binds to MTs through its N-terminal calponin-homologous domain, formed homodimers through its C-terminal coiled coil region to bundle and stabilize MTs. Disruption of either the MT-binding or the dimerization activity abolished the ability of exogenous Spef1 to restore the structure and functions of the CP apparatus. We propose that Spef1 bundles and stabilizes central MTs to enable the assembly and functions of the CP apparatus.


Assuntos
Cílios/metabolismo , Microtúbulos/metabolismo , Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Linhagem Celular , Dimerização , Epêndima/citologia , Epêndima/metabolismo , Humanos , Camundongos , Proteínas dos Microfilamentos/metabolismo , Proteínas dos Microtúbulos/metabolismo , Mutagênese Sítio-Dirigida , Ligação Proteica , Proteínas/antagonistas & inibidores , Proteínas/genética , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Alinhamento de Sequência
15.
Biol Cell ; 111(2): 29-38, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30383886

RESUMO

BACKGROUND INFORMATION: In the "9+2"-type motile cilia, radial spokes (RSs) protruded from the nine peripheral microtubule doublets surround and interact with the central pair (CP) apparatus to regulate ciliary beat. RSPH9 is the human homologue of the essential protozoan RS head protein Rsp9. Its mutations in human primary ciliary dyskinesia patients, however, cause CP loss in a small portion of airway cilia without affecting the ciliary localization of other head proteins. RESULTS: We characterized mouse Rsph9 and investigated its function in ependymal motile cilia. Rsph9 was specifically expressed in mouse tissues containing motile cilia and upregulated during multiciliation. Its ciliary localization complied with its putative role as an RS subunit. Depletion of Rsph9 by RNAi in mouse ependymal cilia resulted in a near complete CP loss and altered the ciliary beat pattern from planar to rotational. Multiple RS proteins, including those in the head, were also markedly downregulated in the Rsph9-depleted cilia. CONCLUSION: Rsph9 is essential for both the RS head assembly and the CP maintenance in mammalian ependymal cilia. SIGNIFICANCE: Our results help to understand the assembly and functions of mammalian RS and pathology of RS-related ciliopathy.


Assuntos
Cílios/metabolismo , Proteínas do Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Animais , Axonema/metabolismo , Axonema/ultraestrutura , Linhagem Celular , Cílios/ultraestrutura , Proteínas do Citoesqueleto/genética , Epêndima/metabolismo , Humanos , Camundongos , Microtúbulos/ultraestrutura , Interferência de RNA
17.
J Mol Cell Biol ; 11(5): 383-394, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30060180

RESUMO

Motile cilia and flagella are microtubule-based organelles important for cell locomotion and extracellular liquid flow through beating. Although axonenal dyneins that drive ciliary beat have been extensively studied in unicellular Chlamydomonas, to what extent such knowledge can be applied to vertebrate is poorly known. In Chlamydomonas, Dynein-f controls flagellar waveforms but is dispensable for beating. The flagellar assembly of its heavy chains (HCs) requires its intermediate chain (IC) IC140 but not IC138. Here we show that, unlike its Chlamydomonas counterpart, vertebrate Dynein-f is essential for ciliary beat. We confirmed that Wdr78 is the vertebrate orthologue of IC138. Wdr78 associated with Dynein-f subunits such as Dnah2 (a HC) and Wdr63 (IC140 orthologue). It was expressed as a motile cilium-specific protein in mammalian cells. Depletion of Wdr78 or Dnah2 by RNAi paralyzed mouse ependymal cilia. Zebrafish Wdr78 morphants displayed ciliopathy-related phenotypes, such as curved bodies, hydrocephalus, abnormal otolith, randomized left-right asymmetry, and pronephric cysts, accompanied with paralyzed pronephric cilia. Furthermore, all the HCs and ICs of Dynein-f failed to localize in the Wdr78-depleted mouse ependymal cilia. Therefore, both the functions and subunit dependency of Dynein-f are altered in evolution, probably to comply with ciliary roles in higher organisms.


Assuntos
Axonema/metabolismo , Cílios/fisiologia , Proteínas do Citoesqueleto/metabolismo , Dineínas/metabolismo , Animais , Dineínas do Axonema/antagonistas & inibidores , Dineínas do Axonema/genética , Dineínas do Axonema/metabolismo , Chlamydomonas/metabolismo , Proteínas do Citoesqueleto/genética , Dineínas/química , Camundongos , Camundongos Endogâmicos C57BL , Morfolinos/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Subunidades Proteicas/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/antagonistas & inibidores , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
18.
Genet Test Mol Biomarkers ; 22(9): 509-517, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30188187

RESUMO

BACKGROUND: The occurrence of cervical cancer is a complex process, for which human papillomavirus (HPV) infection is a risk factor, although not all women infected with HPV will develop the disease. Knockout of mammalian lung metastasis associated transcript 1 (MALAT1) is associated with increased risk for several cancer types, whereas the long non-coding RNA (lncRNA) THRIL is essential for induction of tumor necrosis factor-α expression, which plays important roles in HPV infection. MATERIALS AND METHODS: To investigate the effects of polymorphisms in the lncRNAs MALAT1 and THRIL on the susceptibility to precancerous cervical lesions, 12 single nucleotide polymorphisms (SNPs) were analyzed from 164 cervical precancerous lesion cases and 428 controls. Gene-gene and gene-environment interactions and haplotype associations were also evaluated. RESULTS: We found a significantly decreased risk of precancerous cervical lesions for the THRIL rs7133268 AG genotype (odds ratio adjusted = 0.63, 95% confidence interval: 0.42-0.94, p = 0.025). Multifactor dimensionality reduction analysis identified a significant two-locus interaction model involved in HPV infection and THRIL rs7133268 (training balanced accuracy = 0.6957, testing balanced accuracy = 0.6948, cross-validation consistency = 10/10, p = 0.0046). Other SNPs, including the two identified for MALAT1, were not significantly related to the risk of precancerous cervical lesions. CONCLUSION: Our results suggest that the rs7133268 polymorphism of the lncRNA THRIL gene can reduce the genetic susceptibility of precancerous cervical lesions and in turn reduce the risk of HPV infection.


Assuntos
RNA Longo não Codificante/genética , Neoplasias do Colo do Útero/genética , Adulto , Feminino , Interação Gene-Ambiente , Predisposição Genética para Doença/genética , Genótipo , Haplótipos/genética , Humanos , Pessoa de Meia-Idade , Razão de Chances , Infecções por Papillomavirus/genética , Polimorfismo de Nucleotídeo Único/genética , RNA Longo não Codificante/metabolismo , RNA Longo não Codificante/fisiologia , Fatores de Risco
19.
Eur J Protistol ; 63: 51-61, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29475083

RESUMO

Peatlands cover 3% of the earth's land surface but contain 30% of the world's soil carbon pool. Microbial communities constitute a crucial detrital food web for nutrient and carbon cycling in peatlands. Heterotrophic protozoans are considered top predators in the microbial food web; however, they are not yet well understood. In this study, we investigated seasonal dynamics in the community and the trophic structure of testate amoebae in four peatlands. Testate amoebae density and biomass in August were significantly higher than those in May and October. The highest density, 6.7 × 104 individual g-1 dry moss, was recorded in August 2014. The highest biomass, 7.7 × 102 µg C g-1 dry moss, was recorded in August 2013. Redundancy analyses showed that water-table depth was the most important factor, explaining over one third of the variance in fauna communities in all sampled seasons. High trophic position taxa dominated testate amoebae communities. The Shannon diversity index and community size structure index declined from August to October in 2013 and from May to October in 2014. These seasonal patterns of testate amoebae indicated the seasonal variations of the peatlands' microbial food web and are possibly related to the seasonal carbon dynamics in Northeast Chinese peatlands.


Assuntos
Amoeba/fisiologia , Biodiversidade , Estações do Ano , Amoeba/classificação , China , Dinâmica Populacional , Áreas Alagadas
20.
J Mol Cell Biol ; 10(1): 2-17, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-28992084

RESUMO

AMP-activated protein kinase (AMPK) is an energy sensor that couples the cellular energy state with basic biological processes. AMPK is thought to be linked with cell division although the underlying mechanisms remain largely unknown. Here, we show that AMPK functionally participates throughout cell division and that AMPK catalytic subunits, especially α2, are sequentially associated with separate mitotic apparatus. Using quantitative phosphoproteomics analysis, we found that the strong direct substrate KIF4A is phosphorylated by AMPK at Ser801. Further analysis revealed that AMPK and Aurora B competitively phosphoregulates KIF4A during mitotic phase due to overlapping recognition motifs, resulting in the elaborate phosphoregulation for KIF4A-dependent central spindle length control. Given the intrinsic energy-sensing function of AMPK, our study links the KIF4A-dependent control of central spindle length with cellular glucose stress.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Anáfase , Cinesina/metabolismo , Fuso Acromático/metabolismo , Proteínas Quinases Ativadas por AMP/química , Aurora Quinase B/metabolismo , Domínio Catalítico , Divisão Celular , Células HeLa , Humanos , Mitose , Fosforilação , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Fuso Acromático/ultraestrutura
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