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1.
Nano Lett ; 23(13): 6216-6225, 2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37341290

RESUMO

It remains a challenge to artificially fabricate fibers with the macroscopic mechanical properties and characteristics of spider silk. Herein, a covalently cross-linked double-network strategy was proposed to disrupt the inverse relation of strength and toughness in the fabrication of ultratough and superstrong artificial polymer fibers. Our design utilized a strong fishnet-like structure based on immovable cellulose nanocrystal cross-links to mimic the function of the ß-sheet nanocrystallites and a slidable mechanically interlocked network based on polyrotaxane to imitate the dissipative stick-slip motion of the ß-strands in spider silk. The resultant fiber exhibited superior mechanical properties, including gigapascal tensile strength, a ductility of over 60%, and a toughness exceeding 420 MJ/m3. The fibers also showed robust biological functions similar to those of spider silks, demonstrating mechanical enhancement, energy absorption ability, and shape memory. A composite with our artificial fibers as reinforcing fibers exhibited remarkable tear and fatigue resistance.

2.
Nano Lett ; 21(2): 1047-1055, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33404256

RESUMO

Thermoelectric (TE) technology provides a new way to directly harvest and convert the heat continuously released from the human body. The greatest challenge for TE materials applied in wearable TE generators is compatible with the constantly changing morphology of the human body while offering a continuous and stable power output. Here, a stretchable carboxylic single-walled carbon nanotube (SWNT)-based TE fiber is prepared by an improved wet-spinning method. The stable Seebeck coefficient of the annealed carboxylic SWNT-based TE fiber is 44 µV/K even under the tensile strain of ∼30%. Experimental results show that the fiber can continue to generate constant TE potential when it is changed to various shapes. The new stretchable TE fiber has a larger Seebeck coefficient and more stretchability than existing TE fibers based on the Seebeck effect, opening a path to using the technology for a variety of practical applications.

3.
Zhongguo Zhong Yao Za Zhi ; 47(8): 2257-2265, 2022 Apr.
Artigo em Zh | MEDLINE | ID: mdl-35531743

RESUMO

Through literature research and standard retrieval, Corydalis-derived medicinal materials, the origins, and related standards were summarized. Finally, 27 medicinal materials were screened out, involving 71 species(varieties). Among them, only 11 are recorded in Chinese Pharmacopoeia(2020), National Standard for Chinese Patent Drugs·Tibetan Medicine, Tibetan Medicine Standards, and other local standards, including Corydalis Bungeanae Herba and Corydalis Herba. The names and original plants of the medicinal materials are different in different standards, and the phenomena of "same medicinal material with different names" and "same name for different medicinal materials" are prominent. Most standards only include the traits, microscopic identification, and physico-chemical property identification, with unsound quality criteria. Thus, efforts should be made to strengthen the sorting of Corydalis medicinal plants, herbal textual research, and investigation of the resources and utilization. Moreover, via modern techniques, the chemical components and medicinal material basis of different original plants should be explored and sound quality standards should be established to improve the safety and quality of Corydalis-derived medicinal materials. Summarizing Corydalis medicinal plants, Corydalis-derived medicinal materials, and related standards, this study is expected to provide a reference for the standard formulation, quality evaluation, expansion of drug sources, and rational development and utilization of Corydalis resources.


Assuntos
Corydalis , Medicamentos de Ervas Chinesas , Plantas Medicinais , Medicamentos de Ervas Chinesas/química , Medicina Tradicional Chinesa , Medicina Tradicional Tibetana , Plantas Medicinais/química , Padrões de Referência
4.
Nano Lett ; 20(8): 6176-6184, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32662654

RESUMO

Skin-mountable physical sensors that can individually detect mechanical deformations with high strain sensitivity within a broad working strain range and temperature variations with accurate temperature resolution are a sought-after technology. Herein, a stretchable temperature and strain dual-parameter sensor that can precisely detect and distinguish strain from temperature stimuli without crosstalk is developed, based on a printable titanium carbide (MXene)-silver nanowire (AgNW)-PEDOT:PSS-tellurium nanowire (TeNW) nanocomposite. With this dual-parameter sensor, strain and temperature are effectively transduced into electrically isolated signals through the electrically conductive MXene-AgNW and thermoelectric PEDOT:PSS-TeNW components, respectively. In addition, the synergistic effect between the MXene nanosheets and PEDOT:PSS also greatly enhances the stretchability and sensitivity of the sensing devices. These properties enable the nanocomposite to decouple responses between temperature and strain stimuli with an accurate temperature resolution of 0.2 °C and a gauge factor of up to 1933.3 in a working strain range broader than 60%.


Assuntos
Nanocompostos , Nanofios , Condutividade Elétrica , Prata , Temperatura
5.
Zhongguo Dang Dai Er Ke Za Zhi ; 23(12): 1234-1241, 2021 Dec 15.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-34911606

RESUMO

OBJECTIVES: To study the effect of levothyroxine sodium tablets on the growth and development and thyroid function in preterm infants with thyroid dysfunction. METHODS: A retrospective analysis was performed for 82 preterm infants who were born in the Department of Obstetrics of the First People's Hospital of Yunnan Province, from January 1, 2013 to December 31, 2017, and these infants were hospitalized after birth in the Department of Neonatology of the hospital. They were regularly followed up to observe growth and development and thyroid function at the outpatient service of the Department of Neonatology. According to thyroid function test results, they were divided into an abnormal thyroid function group (observation group; n=31) and a normal thyroid function group (control group; n=51). The infants in the observation group were given oral administration of levothyroxine sodium tablets, while those in the control group were not given any treatment. The two groups were compared in terms of the physical and intelligence development and thyroid function of preterm infants with various gestational ages (28-<32 weeks, 32-<34 weeks, and 34-<37 weeks) after regular follow-up to the corrected age of 12 months. RESULTS: There were no significant differences in physical development indices (body length, body weight, and head circumference) between the observation and control groups at various gestational ages after follow-up to the corrected age of 12 months (P>0.05). There were no significant differences between the two groups in the scores of each functional area of the Gesell Developmental Scale among the preterm infants with a gestational age of 28-<32 weeks and 32-<34 weeks after follow-up to the corrected age of 12 months (P>0.05). For the preterm infants with a gestational age of 34-<37 weeks, compared with the control group, the observation group had a significantly lower score of gross motor ability at the age of 3 and 12 months, significantly lower scores of fine motor ability, language ability, and adaptation ability at the age of 12 months (P<0.05), and a significantly lower score of personal-social ability at the age of 3 months (P<0.05). However, the score of personal-social ability in the observation group was not significantly different from the control group at the age of 12 months (P>0.05). After 2-4 weeks of treatment with levothyroxine sodium tablets, the thyroid function of the 31 preterm infants with thyroid dysfunction returned to normal. Among the 31 infants, 21 (68%) achieved complete drug withdrawal, with normal results of neonatal screening (100%); 10 infants (32%) failed to achieve drug withdrawal, and only 2 (20%) out of the 10 infants had normal neonatal screening results (P<0.05). CONCLUSIONS: Early diagnosis and reasonable treatment can reduce the impact on growth and development in preterm infants with thyroid dysfunction. Most preterm infants tend to have transient thyroid dysfunction, while those with positive results of neonatal screening are more likely to develop permanent thyroid dysfunction.


Assuntos
Preparações Farmacêuticas , Glândula Tireoide , China , Feminino , Seguimentos , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Gravidez , Estudos Retrospectivos
6.
J Eukaryot Microbiol ; 66(5): 694-706, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30657224

RESUMO

A new hypotrichous ciliate, Schmidtiella ultrahalophila gen. nov., spec. nov., was isolated from a solar saltern on the island of Sal, Cape Verde. The possession of only one short dorsal kinety clearly distinguishes S. ultrahalophila from other known hypotrichous genera and species. Further diagnostic characters include: a flexible and slender body, an average size of 85 × 15 µm in vivo; a bipartite adoral zone with two hypertrophied frontal adoral membranelles and nine to twelve ventral adoral membranelles; three frontal, one parabuccal, two frontoventral, two or three postoral ventral, and two or three frontoterminal cirri; and marginal cirral rows variable in number, usually one on each side. Ontogenetic data indicate the following: the frontal-ventral cirri originate from six or five anlagen; the proter inherits the parental adoral zone; the frontal and ventral cirri originate from five or six anlagen; and the marginal cirral rows and the dorsal kinety tend to originate intrakinetally. Additional marginal rows are rarely derived from de novo anlagen. Based on its morphology, morphogenesis and its SSU rRNA phylogenetic placement, the new species should be assigned to the order Sporadotrichida Fauré-Fremiet, 1961. Due to low taxon sampling, however, its exact position in this order remains enigmatic.


Assuntos
Cilióforos/crescimento & desenvolvimento , Cilióforos/isolamento & purificação , Filogenia , Cabo Verde , Cilióforos/classificação , Cilióforos/genética , Ilhas , Morfogênese
7.
J Eukaryot Microbiol ; 65(5): 627-636, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29397037

RESUMO

The morphology and morphogenesis of a new soil hypotrich ciliate, Sterkiella multicirrata sp. nov., was investigated using live observation and protargol staining. The new species is characterised by: body elliptical, 110-180 × 45-75 µm in vivo, an average of 35 adoral membranelles; usually 19 frontoventral-transverse cirri, consisting of three frontal, five frontoventral, one buccal, four postoral ventral, two pretransverse, and four transverse cirri; four macronuclear nodules, and 2-5 micronuclei. S. multicirrata sp. nov. differs from its congeners mainly in the number of frontoventral-transverse cirri and macronuclear nodules. Morphogenesis of the new species is similar to its congeners; the primary difference exists in the segmentation of the frontoventral-transverse cirral anlagen, which is usually generated in a 1:2:3:3:5:5 pattern. Based on the small subunit ribosomal DNA sequence, the phylogenetic position of the new species is discussed.


Assuntos
Hypotrichida/crescimento & desenvolvimento , Hypotrichida/isolamento & purificação , Solo/parasitologia , China , DNA de Protozoário/genética , DNA Ribossômico/genética , Hypotrichida/classificação , Hypotrichida/genética , Morfogênese , Filogenia
8.
J Eukaryot Microbiol ; 65(1): 132-142, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28544395

RESUMO

The morphology and molecular phylogeny of a soil hypotrich ciliate, Pseudourostyla guizhouensis sp. nov., collected from southern China, were investigated. Pseudourostyla guizhouensis sp. nov. has an elongate elliptical body measuring 180-310 × 65-85 µm in vivo; invariably two right and three or four left marginal rows; six or seven dorsal kineties; adoral zone consisting of 57-70 membranelles; 12-16 frontal cirri, one buccal cirrus, 13-20 midventral pairs, two frontoterminal cirri, two pretransverse cirri, and five to seven transverse cirri. Morphogenesis during physiological regeneration indicates that the marginal rows of each side originate from a common anlage that differentiates into several rows. Molecular phylogenetic analysis based on SSU rDNA sequence data reveals that P. guizhouensis sp. nov. clusters with the type species P. cristata (Jerka-Dziadosz, 1964) Borror, 1972 and that the genus Pseudourostyla is monophyletic. The morphological characters of another soil hypotrich ciliate, Hemicycliostyla franzi (Foissner, 1987) Paiva et al., 2012, are also described based on a Chinese (Guizhou) population.


Assuntos
Hypotrichida/classificação , Filogenia , Solo/parasitologia , China , DNA de Protozoário/análise , DNA Ribossômico/análise , Hypotrichida/citologia , Hypotrichida/genética , Microscopia de Interferência , Análise de Sequência de DNA
9.
J Am Chem Soc ; 139(31): 10617-10620, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28742335

RESUMO

In situ generation of 5-formylcytosine (5fC) in nucleosome core particles (NCPs) reveals that 5fC leads to essential DNA-protein cross-links (DPCs). Mechanistic studies using chemical models and mutated histones demonstrate that DPCs form reversibly between the formyl function of 5fC and primary amines on histones. These results suggest that DPC formation from 5fC in chromatin occurs in addition to its role in DNA demethylation.


Assuntos
Citosina/análogos & derivados , DNA/metabolismo , Nucleossomos/química , Proteínas/metabolismo , Citosina/química , DNA/química , Eletroforese em Gel de Poliacrilamida , Cinética , Modelos Biológicos , Estrutura Molecular , Proteínas/química , Bases de Schiff/química
10.
Int J Syst Evol Microbiol ; 64(Pt 11): 3775-3785, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25139418

RESUMO

The morphology and morphogenesis of a soil hypotrichous ciliate, Deviata parabacilliformis sp. nov., isolated from northern China, were investigated. D. parabacilliformis measures about 75-210 × 25-60 µm in vivo, with an elongate and flexible body. It possesses one right marginal row, two to four left marginal rows and three dorsal kineties. The main morphogenetic features of D. parabacilliformis are: (i) the oral primordium originates de novo; (ii) anlage IV of the opisthe originates from parental frontoventral row V, anlage V originates de novo, and anlage VI forms from frontoventral row VI; and (iii) anlage I of the proter originates from the anterior portion of the parental paroral, anlage II originates from the buccal cirrus, anlage III originates from the parabuccal cirri, anlage IV originates from parental frontoventral row IV and anlage V forms from the anterior of parental frontoventral row VI. The morphology of an edaphic population of another species of the genus Deviata, Deviata bacilliformis (Gelei 1954) Eigner 1995, was also investigated. This work also provides the first record of SSU rRNA gene sequences for species of the genus Deviata. Molecular phylogenetic analysis suggests that Deviata is not monophyletic, and its position is poorly resolved due to weak phylogenetic signal of the 18S marker in the Stichotrichida.


Assuntos
Cilióforos/classificação , Genes de RNAr , Filogenia , Microbiologia do Solo , Sequência de Bases , China , Cilióforos/citologia , Cilióforos/genética , Cilióforos/isolamento & purificação , Genes de Protozoários , Dados de Sequência Molecular , Análise de Sequência de DNA
11.
World J Microbiol Biotechnol ; 30(11): 2899-905, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25096202

RESUMO

Marine organisms have usually been viewed as sources of environmentally friendly compounds with antifouling activity. We performed a series of operations to investigate the antifouling potential of the marine microalga Dunaliella salina. For the ethyl acetate crude extract, the antialgal activity was significant, and the EC50 value against Skeletonema costatum was 58.9 µg ml(-1). The isolated purified extract was tested for antifouling activity, the EC 50 value against S. costatum was 21.2 µg ml(-1), and the LC50 against Balanus amphitrite larvae was 18.8 µg ml(-1). Subsequently, both UHR-TOF-MS and GC-MS were used for the structural elucidation of the compounds, and a series of unsaturated and saturated 16- and 18-carbon fatty acids were detected. The data suggested that the fatty acid extracts from D. salina possess high antifouling activity, and could be used as substitutes for potent, toxic antifouling compounds.


Assuntos
Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/metabolismo , Diatomáceas/efeitos dos fármacos , Thoracica/efeitos dos fármacos , Volvocida/química , Animais , Anti-Infecciosos/química , Organismos Aquáticos/química , Larva/efeitos dos fármacos , Espectrometria de Massas
12.
Eur J Protistol ; 92: 126048, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38118326

RESUMO

The morphology and morphogenesis of a new urostylid, Holostichides (Extraholostichides) eastensis tianjinensis subgen. nov. subspec. nov. were analyzed. The new subspecies differs from the nominotypical subspecies H. (Extraholostichides) eastensis eastensis Wang et al., 2022 by the relatively long frontoterminal row (about 60% vs. 30% of body length), colorless cortical granules (vs. dark brown), two (vs. one) parabuccal cirri, and usually an extra cirrus behind the first midventral pair (vs. lacking). Based on the difference in the frontal ciliature, we split Holostichides into two subgenera: H. (Extraholostichides) subgen. nov. (type species Holostichides eastensis Wang et al., 2022; with a short cirral row behind the middle frontal cirrus) and H. (Holostichides) Foissner, 1987 (type species Holostichides chardezi Foissner, 1987; lacking this short row). The main morphogenetic characters of the new subspecies are very similar to those of H. (Extraholostichides) eastensis eastensis except for some minor differences. Phylogenetic analyses based on SSU rDNA sequences indicate that H. (Extraholostichides) subgen. nov. is monophyletic and nested within the monophyletic genus Holostichides, which is sister to Eschaneustyla lugeri.


Assuntos
Cilióforos , Filogenia , DNA Ribossômico/genética , Cilióforos/genética , China , Morfogênese , Especificidade da Espécie
13.
J Int Med Res ; 52(6): 3000605241254778, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38835107

RESUMO

Pulmonary blastoma (PB) is a rare, highly malignant tumor prone to distant metastasis and recurrence, and the prognosis of these patients is often poor. We report a case of metastatic PB with a good prognosis with the aim of providing data to support a clinical diagnosis and treatment. In December 2015, a 43-year-old male patient was admitted to our hospital because of a cough and blood-stained sputum. Positron emission-computed tomography showed massive high-density imaging in the lower lobe of the right lung, with a maximum cross-section of 76 × 58 mm. Thoracoscopic-assisted right lower lobectomy with lymph node dissection was performed. After 1 month, computed tomography showed a high possibility of metastasis. The patient then received docetaxel and cisplatin chemotherapy for a total of six courses. After chemotherapy, enhanced computed tomography showed considerable absorption of pleural effusion, and a left lobe pulmonary nodule was not detected. The postoperative pathological diagnosis was PB, and epithelial and mesenchymal differentiation components were observed. The patient continued to visit the hospital regularly for re-examination and imaging examinations. Currently, no signs of recurrence or distant metastasis have been detected.


Assuntos
Neoplasias Pulmonares , Blastoma Pulmonar , Humanos , Masculino , Adulto , Blastoma Pulmonar/diagnóstico , Blastoma Pulmonar/patologia , Blastoma Pulmonar/cirurgia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/cirurgia , Neoplasias Pulmonares/diagnóstico por imagem , Prognóstico , Tomografia Computadorizada por Raios X , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Cisplatino/uso terapêutico , Cisplatino/administração & dosagem , Pneumonectomia , Docetaxel/uso terapêutico , Docetaxel/administração & dosagem
14.
J Eukaryot Microbiol ; 60(3): 247-56, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23489279

RESUMO

The morphology, morphogenesis, and 18S rRNA gene sequence of a soil hypotrichous ciliate Perisincirra paucicirrata, isolated from north China, were investigated. Perisincirra paucicirrata differs from its congeners in: (1) having a body length to width ratio in vivo of 4:1, (2) its adoral zone occupying between 15% and 25% of the total body length, and (3) the presence of two parabuccal cirri, three left (with 10-16 cirri each) and two right marginal rows (with 14-24 cirri each), and three dorsal kineties. Our study offers a first attempt to begin to map the morphogenetic processes of the genus, which are mainly characterised by the following: the formation of four frontal ventral transverse anlagens for each daughter cell, with the proter's anlage I originating from the reorganised anterior part of the parental paroral; the paroral and endoral anlage developed from the reorganised old endoral and do not contribute the first frontal cirrus; the frontoventral transverse anlage I contributing the left frontal cirrus; anlage II generating the middle frontal and the buccal cirri; anlage III developing the right frontal cirrus and the anterior parabuccal cirrus; and anlage IV contributing the posterior parabuccal cirrus. As an additional contribution, we judge that the inner one or the two right rows of P. kahli and P. longicirrata are marginal rows. Phylogenetic analysis based on SSU rDNA sequences suggests that Perisincirra is related to sporadotrichids, but provides no credible evidence for its taxonomic position.


Assuntos
Genes de RNAr/genética , Hypotrichida/genética , China , Cilióforos/classificação , Cilióforos/genética , Hypotrichida/classificação , Filogenia , RNA Ribossômico 18S/genética
15.
Chem Asian J ; 18(16): e202300474, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37427996

RESUMO

With the impetus of flexible electronics and micro-nano fabrication technology, the human demand for flexible intelligent wearable devices is on an upsurge. In recent years, new functional fibers have undergone rapid development and emerged as an indispensable carrier of flexible wearable e-textiles. However, to achieve their functional applications and durability, new functional fibers must possess good electrical and mechanical properties. As an emerging two-dimensional material, MXenes have attracted immense attention for their high electrical conductivity, mechanical strength, specific surface area, adjustable surface properties, and exceptional processability. As such, MXenes have become an ideal candidate for the primary functional component of functional fibers. This paper presents a comprehensive review of research progress on MXene-based fibers in the construction of flexible wearable electronic textiles. Firstly, we briefly outline the preparation methods of MXenes materials. Next, we summarize the processing types of MXene-based fibers and highlight their performance parameters. Lastly, we summarize the primary application scenarios of MXene-based fibers and anticipate the future development of flexible wearable e-textiles.

16.
Front Plant Sci ; 14: 1074184, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36844064

RESUMO

Plant-derived natural products are important resources for pesticide discovery. Acetylcholinesterase (AChE) is a well-validated pesticide target, and inhibiting AChE proves fatal for insects. Recent studies have shown that the potential of various sesquiterpenoids as AChE inhibitors. However, few studies have been conducted with eudesmane-type sesquiterpenes with AChE inhibitory effects. Therefore, in this research, we isolated two new sesquiterpenes, laggeranines A (1) and B (2), along with six known eudesmane-type sesquiterpenes (3-8) from Laggera pterodonta, and characterized their structures and the inhibitory effect they exerted on AChE. The results showed that these compounds had certain inhibitory effects on AChE in a dose-dependent manner, of which compound 5 had the best inhibitory effect with IC50 of 437.33 ± 8.33 mM. As revealed by the Lineweaver-Burk and Dixon plots, compound 5 was observed to suppress AChE activity reversibly and competitively. Furthermore, all compounds exhibited certain toxicity levels on C. elegans. Meanwhile, these compounds had good ADMET properties. These results are significant for the discovery of new AChE targeting compounds, and also enrich the bioactivity activity repertoire of L. pterodonta.

17.
Adv Mater ; 35(15): e2209527, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36661125

RESUMO

Textile electronics are needed that can achieve strain-unaltered performance when they undergo irregular and repeated strain deformation. Such strain-unaltered textile electronics require advanced fibers that simultaneously have high functionalities and extreme robustness as fabric materials. Current synthetic nanocomposite fibers based on inorganic matrix have remarkable functionalities but often suffer from low robustness and poor tolerance against crack formation. Here, we present a design for a high-performance multifunctional nanocomposite fiber that is mechanically and electrically robust, which was realized by crosslinking titanium carbide (MXene) nanosheets with a slide-ring polyrotaxane to form an internal mechanically-interlocked network. This inorganic matrix nanocomposite fiber featured distinct strain-hardening mechanical behavior and exceptional load-bearing capability (toughness approaching 60 MJ m-3 and ductility over 27%). It retained 100% of its ductility after cyclic strain loading. Moreover, the high electrical conductivity (>1.1 × 105 S m-1 ) and electrochemical performance (>360 F cm-3 ) of the nanocomposite fiber can be well retained after subjecting the fiber to extensive (>25% strain) and long-term repeated (10 000 cycles) dimensional changes. Such superior robustness allowed for the fabrication of the nanocomposite fibers into various robust wearable devices, such as textile-based electromechanical sensors with strain-unalterable sensing performance and fiber-shaped supercapacitors with invariant electrochemical performance for 10 000 strain loading cycles.

18.
Sci Total Environ ; 848: 157565, 2022 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-35907523

RESUMO

Daphnia magna is one of the most commonly used model organisms to assess toxicity of heavy metal and other xenobiotics. However, the lack of knowledge about important stress-resistant molecules limits our understanding of the alteration of phenotypic and physiological traits of D. magna upon stress exposures. In this study, we focused on a chaperone family of small heat shock protein (sHSP) that has been found in archaea, bacteria and eukaryotes and plays an important role in stress tolerance. A total of eleven sHSP genes (termed DmsHSP1 - DmsHSP11) were identified from the D. magna genome, whose expression profiles during exposure to heavy metal (Cd2+, Cu2+ and Zn2+) and a few other potential pollutants were evaluated via qRT-PCR and RNA-Seq analysis. The results highlighted the predominant role of DmsHSP1 with the highest basal expression level in adults and robust upregulation upon exposure to heavy metals (Cu2+ > Cd2+ > Zn2+). In vivo, recombinant protein rDmsHSP1-21 and rDmsHSP11-12.8 could not only prevent model substrates agglutination induced by heavy metals or reducer dithiotreitol (DTT), but also protect tissue proteins and enzymes from denaturation and inactivation caused by heavy metals or high temperature. Ectopically expression of DmsHSP1-21 or DmsHSP11-12.8 in E. coli conferred host enhanced resistance against various abiotic stresses including Cd2+, Cu2+ and phenazine methosulfate (PMS). Knockdown of DmsHSP1-21 by RNAi, but not for DmsHSP11-12.8, significantly increased the vulnerability of D. magna to heavy metal exposure. Our work provides systematic information on the evolution and function of sHSPs in D. magna and leads to important insights into the mechanisms by which D. magna survive in adverse environments.


Assuntos
Proteínas de Choque Térmico Pequenas , Metais Pesados , Poluentes Químicos da Água , Animais , Cádmio/metabolismo , Daphnia , Escherichia coli/metabolismo , Proteínas de Choque Térmico Pequenas/genética , Proteínas de Choque Térmico Pequenas/metabolismo , Proteínas de Choque Térmico Pequenas/farmacologia , Metais Pesados/metabolismo , Metais Pesados/toxicidade , Metilfenazônio Metossulfato/metabolismo , Metilfenazônio Metossulfato/farmacologia , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Poluentes Químicos da Água/metabolismo
19.
PLoS One ; 16(11): e0260040, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34793525

RESUMO

Share pledging has become popular as a method of loan collateral among Chinese shareholders. Our research used a sample of Chinese listed firms between 2008-2018 and produced two main findings. Firstly, we found a negative association between stock price risk and firm profitability. Our second finding was that the interaction effect of share pledging and stock price risk is greater on firm profitability than the effect of stock price risk itself. We examined the role of share pledging by modeling pooled OLS and fixed effects using share pledging behavior, controlling shareholders' share pledging and the share pledging ratio to reinforce the robustness of our results. Furthermore, we investigated the Davis Double Play effect of share pledging to analyze how share pledging affects stock price risk. We found that higher EPS and investor expectations cannot mitigate the positive impact of share pledging on stock price risk. That is, the reduction of EPS and the deterioration of investor expectations caused by share pledging risk will not further aggravate the stock price risk, as shareholders may have taken some managerial actions to affect the transmission mechanism.


Assuntos
Comércio/tendências , Investimentos em Saúde/economia , Investimentos em Saúde/tendências , Povo Asiático/psicologia , China , Financiamento Pessoal/tendências , Humanos , Modelos Econômicos , Medição de Risco/economia
20.
Front Microbiol ; 12: 774226, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35222294

RESUMO

Because the original description of Bakuella (Bakuella) marina, type of the genus, is only based on protargol-impregnated specimens, one of the important living features, namely, the presence/absence of cortical granules, remains unknown so far. In the present work, a detailed investigation of a Chinese population of B. (Bakuella) marina is carried out using the integrated approaches, and the live morphology, ontogenesis, and molecular information of B. (Bakuella) marina are presented for the first time. The infraciliature of this population corresponds perfectly with that of the original description. The in vivo observation indicates that B. (Bakuella) marina possesses colorless cortical granules. The most prominent morphogenetic feature of B. (Bakuella) marina is that the parental adoral zone of membranelles is completely replaced by the newly formed one of the proters. Molecular phylogenetic analysis based on a small subunit ribosomal gene (SSU rDNA) shows that five Bakuella species are clustered with the species from other six Urostylid genera, namely, Anteholosticha, Apobakuella, Diaxonella, Holosticha, Neobakuella, and Urostyla. The monophyletic probabilities of the family Bakuellidae, genus Bakuella, subgenus B. (Bakuella), and subgenus B. (Pseudobakuella) are rejected by the approximately unbiased test. This study further shows that the family Bakuellidae, genus Bakuella, and subgenus B. (Bakuella) are all nonmonophyletic groups. In order to establish a reasonable classification system, information on molecular and morphogenesis of more Bakuellids and its related species is urgently needed.

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