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1.
J Infect Chemother ; 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39128616

RESUMO

OBJECTIVE: To clarify the infection control measures required in the event of a new infectious disease outbreak, we conducted a questionnaire survey on the infection control measures implemented against coronavirus disease 2019 (COVID-19). METHODS: An invitation to participate in this survey was sent to the heads of 2689 facilities affiliated with the members of the Japanese Society for Infection Prevention and Control in February 2023, requesting responses to the online survey using Google Forms by March 2023. RESULTS: Six hundred and forty-five facilities, including 20 clinics and 625 hospitals, participated in the survey. This survey revealed that various infection control measures were implemented, including universal masking in the non-COVID-19 ward (96.5 %), screening tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on scheduled admission (89.0 %), SARS-CoV-2 tests (98.7 %), and isolation in private rooms (76.5 %) for inpatients with fever. However, nosocomial infections and clusters of COVID-19 occurred in 94.4 % and 90.9 % of cases during the investigation period, respectively. One of the reasons for these results is that healthcare personnel (HCP) and patients were common index cases of nosocomial infections, and the most common cause of clusters was the work of symptomatic HCPs. These results suggest that HCPs should understand that they can be index cases or spreaders. On the other hand, the most common support from external facilities was healthcare centers, followed by physicians or nurses from other hospitals. CONCLUSION: In response to the emergence of infections, it is important to consider implementing infection control measures for HCPs and patients.

2.
Chem Sci ; 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39170722

RESUMO

The self-assembly of d8 transition metal complexes is essential for the development of optoelectronic and sensing materials with superior photofunctional properties. However, detailed insight into the electronic delocalization of excited states across multiple molecules, particularly in comparing 5d8 (Pt(ii)) and 4d8 (Pd(ii)) systems, remains ambiguous but important. In this study, we have successfully evaluated the differences in the excited-state delocalization and thermal responses of self-assembled Pt(ii) and Pd(ii) complexes. Although the complexes presented herein, K[M(CN)2(dFppy)]·H2O (M = Pt or Pd, dFppy = 2-(4,6-difluorophenyl)pyridinate), are crystallographically isomorphous with similarly short metal⋯metal contacts, only the Pt(ii) complex exhibited thermal equilibria between delocalized excited states, resulting in a drastic thermochromic luminescence with a red-shift of greater than 100 nm. In contrast, the dimeric localized emission from the Pd(ii) complex showed a significant increase in the quantum yield upon cooling, approaching almost unity.

3.
Inorg Chem ; 63(33): 15323-15330, 2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39119626

RESUMO

The development of Zn-based phosphorescent materials, associated with a ligand-centered (LC) transition, is extremely limited. Herein, we demonstrated dual emissions including fluorescence and phosphorescence in luminescent tetranuclear Zn(II) clusters [Zn4LI4(µ3-OMe)2X2] (HLI = methyl-5-iode-3-methoxysalicylate; X = I, Br, Cl), incorporating iodine-substituted ligands. Single-crystal X-ray structural analyses and variable-temperature emission spectra studies revealed the presence of iodine substitutions, and intermolecular halogen interactions produced the internal/external heavy-atom effects and yielded strong green phosphorescence with a long emission lifetime (λmax = 510-522 nm, Φem = 0.28-0.47, τav = 0.78-0.95 ms, at 77 K). This work provided a new example that the introduction of halogen interactions is an advantageous approach for inducing phosphorescence in fluorescent metal complexes.

4.
Front Microbiol ; 15: 1430557, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39050631

RESUMO

In the 2010s, several unusual rotavirus strains emerged, causing epidemics worldwide. This study reports a comprehensive molecular epidemiological study of rotaviruses in Japan based on full-genome analysis. From 2014 to 2019, a total of 489 rotavirus-positive stool specimens were identified, and the associated viral genomes were analyzed by next-generation sequencing. The genotype constellations of those strains were classified into nine patterns (G1P[8] (Wa), G1P[8]-E2, G1P[8] (DS-1), G2P[4] (DS-1), G3P[8] (Wa), G3P[8] (DS-1), G8P[8] (DS-1), G9P[8] (Wa), and G9P[8]-E2). The major prevalent genotype differed by year, comprising G8P[8] (DS-1) (37% of that year's isolates) in 2014, G1P[8] (DS-1) (65%) in 2015, G9P[8] (Wa) (72%) in 2016, G3P[8] (DS-1) (66%) in 2017, G1P[8]-E2 (53%) in 2018, and G9P[8] (Wa) (26%) in 2019. The G1P[8]-E2 strains (G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1) isolated from a total of 42 specimens in discontinuous years (2015 and 2018), which were the newly-emerged NSP4 mono-reassortant strains. Based on the results of the Bayesian evolutionary analyses, G1P[8]-E2 and G9P[8]-E2 were hypothesized to have been generated from distinct independent inter-genogroup reassortment events. The G1 strains detected in this study were classified into multiple clusters, depending on the year of detection. A comparison of the predicted amino acid sequences of the VP7 epitopes revealed that the G1 strains detected in different years encoded VP7 epitopes harboring distinct mutations. These mutations may be responsible for immune escape and annual changes in the prevalent strains.

5.
J Med Virol ; 96(7): e29780, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38965887

RESUMO

Human adenovirus (HAdV) infections present diverse clinical manifestations upon infecting individuals, with respiratory infections predominating in children. We surveyed pediatric hospitalizations due to respiratory HAdV infections across 18 hospitals in Hokkaido Prefecture, Japan, from July 2019 to March 2024, recording 473 admissions. While hospitalizations remained below five cases per week from July 2019 to September 2023, a notable surge occurred in late October 2023, with weekly admissions peaking at 15-20 cases from November to December. There were dramatic shifts in the age distribution of hospitalized patients: during 2019-2021, 1-year-old infants and children aged 3-6 years represented 51.4%-54.8% and 4.1%-13.3%, respectively; however, in 2023-2024, while 1-year-old infants represented 19.0%-20.1%, the proportion of children aged 3-6 years increased to 46.2%-50.0%. Understanding the emergence of significant outbreaks of respiratory HAdV infections and the substantial changes in the age distribution of hospitalized cases necessitates further investigation into the circulating types of HAdV in Hokkaido Prefecture and changes in children's neutralizing antibody titers against HAdV.


Assuntos
Infecções por Adenovirus Humanos , Adenovírus Humanos , Surtos de Doenças , Hospitalização , Infecções Respiratórias , Humanos , Japão/epidemiologia , Infecções por Adenovirus Humanos/epidemiologia , Infecções por Adenovirus Humanos/virologia , Pré-Escolar , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Criança , Adenovírus Humanos/isolamento & purificação , Adenovírus Humanos/classificação , Masculino , Feminino , Hospitalização/estatística & dados numéricos , Lactente
6.
Cureus ; 16(5): e59726, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38841025

RESUMO

PURPOSE: This study aimed to investigate the potential of a newly developed small electrode to accurately record muscle activity during swallowing. MATERIAL AND METHODS: This study included 31 healthy participants. The participants underwent swallowing trials with three types of material. The recordings involved the following conditions: 1) swallowing saliva, 2) swallowing 3 mL water, and 3) swallowing 5 mL water. Two types of electrodes, a conventional electrode (CE) and a newly developed small electrode (NE), were symmetrically positioned on the skin over the suprahyoid muscle group, starting from the center. From the surface electromyography data, the swallowing duration (s), peak amplitude, and rising time (duration from swallowing onset to peak amplitude: s) were measured. Additionally, the equivalence of characteristics of the waveform of muscle activities was calculated by using the variance in both the upper and lower confidence limits in duration and rising time. RESULTS: No significant differences in baseline, swallowing duration or rising time between the CE and NE were observed for any swallowing material. The peak amplitude was significantly higher for the NE than for the CE for all swallowing materials. The CE and NE displayed no significant difference in the equivalence of characteristics of the waveform of muscle activities for any swallowing material. CONCLUSIONS: The gold-plated small electrodes utilized in this study indicated the ability to record the same characteristics of muscle activity as conventional electrodes. Moreover, it was able to capture the muscle activity of each muscle group with improved sensitivity in a narrow area, such as under the submandibular region, with more precision than that of conventional electrodes.

7.
Dalton Trans ; 53(29): 12064-12072, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38616678

RESUMO

Porous molecular crystals (PMCs) have gained significant importance as next-generation functional porous materials. However, the selective crystallisation of the PMC phase remains a challenge. Herein, we have systematically controlled the stability of the luminescent PMC phase prepared using the luminescent Pt(II) complex [Pt(pbim)(N^O)] (pbim = 2-phenylbenzimidazolate, N^O = N-heteroaryl carboxylate) with Pt⋯Pt electronic interactions. The PMC phase formation varied significantly among the complexes depending on the heteroaryl group of the ancillary N^O ligand; the oxazolyl-bearing complex did not form a PMC phase, whereas the pyrazyl- and 5-fluoropyridyl-bearing complexes spontaneously formed a porous structure. This difference was rationalised by the π-stacking capability of the heteroaryl group of the ancillary ligand. Furthermore, owing to the presence of the one-dimensional Pt⋯Pt chains in this PMC phase, the photophysical properties of PMCs resulting from the Pt⋯Pt interactions were also significantly changed by the ancillary ligands.

8.
IDCases ; 36: e01952, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38659621

RESUMO

Introduction: Fluconazole is commonly used to treat and prevent fungal infections caused by Candida and Cryptococcus species. Although there have been reports of fatal arrhythmias induced by fluconazole, such as torsades de pointes, there have been minimal reports of mild, non-fatal arrhythmias associated with it, which may have been overlooked in clinical practice. We encountered a case of frequent premature ventricular contractions induced by fluconazole during the treatment of HIV-related pulmonary cryptococcosis. Herein, we report a case of frequent premature ventricular contractions (PVCs) induced by fluconazole, along with a literature review. Case presentation: A 47-year-old man diagnosed with human immunodeficiency virus-related pulmonary cryptococcosis experienced an irregular heartbeat during antifungal therapy with fluconazole at 400 mg once daily. A 12-lead electrocardiogram was conducted, which displayed frequent unifocal PVCs originating in the right ventricular outflow tract without QT prolongation. After reducing the dose of fluconazole to 200 mg once daily, the patient's symptoms slightly improved, and PVC frequency decreased on a 12-lead ECG; however, PVCs did not disappear. After discontinuing fluconazole, the symptoms improved, and a follow-up 12-lead electrocardiogram showed no PVCs. Conclusions: We encountered the case of frequent PVCs induced by fluconazole during the treatment of human immunodeficiency virus-related pulmonary cryptococcosis. Furthermore, it was suggested that the PVC frequency was dose-dependent for fluconazole. Careful follow-up for new-onset arrhythmias and ECG evaluations are essential before and after fluconazole administration.

9.
J Gen Appl Microbiol ; 70(1)2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-38233172

RESUMO

We investigated the presence and functionality of the carbon storage regulator (Csr) system in Aeromonas salmonicida SWSY-1.411. CsrA, an RNA-binding protein, shared 89% amino acid sequence identity with Escherichia coli CsrA. CsrB/C sRNAs exhibited a typical stem-loop structure, with more GGA motifs, which bind CsrA, than E. coli. CsrD had limited sequence identity with E. coli CsrD; however, it contained the conserved GGDEF and EAL domains. Functional analysis in E. coli demonstrated that the Csr system of A. salmonicida influences glycogen biosynthesis, biofilm formation, motility, and stability of both CsrB and CsrC sRNAs. These findings suggest that in A. salmonicida, the Csr system affects phenotypes like its E. coli counterpart. In A. salmonicida, defects in csr homologs affected biofilm formation, motility, and chitinase production. However, glycogen accumulation and protease production were unaffected. The expression of flagellar-related genes and chitinase genes was suppressed in the csrA-deficient A. salmonicida. Northern blot analysis indicated the stabilization of CsrB and CsrC in the csrD-deficient A. salmonicida. Similar to that in E. coli, the Csr system in A. salmonicida comprises the RNA-binding protein CsrA, the sRNAs CsrB and CsrC, and the sRNA decay factor CsrD. This study underscores the conservation and functionality of the Csr system and raises questions about its regulatory targets and mechanisms in A. salmonicida.


Assuntos
Aeromonas salmonicida , Proteínas de Bactérias , Biofilmes , Escherichia coli , Regulação Bacteriana da Expressão Gênica , Estabilidade de RNA , RNA Bacteriano , Proteínas de Ligação a RNA , Aeromonas salmonicida/genética , Aeromonas salmonicida/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Biofilmes/crescimento & desenvolvimento , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , RNA Bacteriano/genética , Glicogênio/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Sequência de Aminoácidos , Proteínas Repressoras
10.
Dalton Trans ; 53(4): 1445-1448, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38197251

RESUMO

A coordination polymer, [Cu(SCN)(iqi)]n (iqi = isoquinoline), containing copper(I) thiocyanate and a nitrogen-containing π-conjugated ligand, iqi, has been synthesized and its physical properties were evaluated. This coordination polymer has a two-dimensional (2D) sheet structure consisting of copper(I) thiocyanate and shows photoluminescence derived from 3MLCT and photoconductive properties.

11.
J Med Virol ; 95(12): e29299, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-38081792

RESUMO

Following the coronavirus disease 2019 (COVID-19) outbreak in February 2020, incidences of various infectious diseases decreased notably in Hokkaido Prefecture, Japan. However, Japan began gradually easing COVID-19 infection control measures in 2022. Here, we conducted a survey of children hospitalized with human metapneumovirus (hMPV), influenza A and B, and respiratory syncytial virus infections in 18 hospitals across Hokkaido Prefecture, Japan, spanning from July 2019 to June 2023. From March 2020 to June 2022 (28 months), only 13 patients were hospitalized with hMPV, and two patients had influenza A. However, in October to November 2022, there was a re-emergence of hMPV infections, with a maximum of 27 hospitalizations per week. From July 2022 to June 2023 (12 months), the number of hMPV-related hospitalizations dramatically increased to 317 patients, with the majority aged 3-6 years (38.2%, [121/317]). Influenza A also showed an increase from December 2022, with a peak of 13 hospitalizations per week in March 2023, considerably fewer than the pre-COVID-19 outbreak in December 2019, when rates reached 45 hospitalizations per week. These findings suggest the possibility of observing more resurgences in infectious diseases in Japan after 2023 if infection control measures continue to be relaxed. Caution is needed in managing potential outbreaks.


Assuntos
COVID-19 , Doenças Transmissíveis , Influenza Humana , Metapneumovirus , Infecções por Paramyxoviridae , Infecções por Vírus Respiratório Sincicial , Infecções Respiratórias , Criança , Humanos , Lactente , Influenza Humana/epidemiologia , Estações do Ano , Japão/epidemiologia , COVID-19/epidemiologia , Infecções por Paramyxoviridae/epidemiologia , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções Respiratórias/epidemiologia
12.
Nat Commun ; 14(1): 7486, 2023 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-37980351

RESUMO

Colloidal quantum dots are sub-10 nm semiconductors treated with liquid processes, rendering them attractive candidates for single-electron transistors operating at high temperatures. However, there have been few reports on single-electron transistors using colloidal quantum dots due to the difficulty in fabrication. In this work, we fabricated single-electron transistors using single oleic acid-capped PbS quantum dot coupled to nanogap metal electrodes and measured single-electron tunneling. We observed dot size-dependent carrier transport, orbital-dependent electron charging energy and conductance, electric field modulation of the electron confinement potential, and the Kondo effect, which provide nanoscopic insights into carrier transport through single colloidal quantum dots. Moreover, the large charging energy in small quantum dots enables single-electron transistor operation even at room temperature. These findings, as well as the commercial availability and high stability, make PbS quantum dots promising for the development of quantum information and optoelectronic devices, particularly room-temperature single-electron transistors with excellent optical properties.

13.
Chemistry ; 29(60): e202303224, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37830449

RESUMO

Invited for the cover of this issue is the group of Masaki Yoshida and Masako Kato at Hokkaido University/Kwansei Gakuin University. The image depicts the changes in the assembly of PtII complexes with humidity on layered double hydroxide (LDH) nanoparticles, resulting in a drastic emission color change from green to orange. Read the full text of the article at 10.1002/chem.202301993.

14.
J Am Chem Soc ; 145(34): 19060-19066, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37603330

RESUMO

Tri(t-butyl)phosphine and terminal alkynes undergo 1,2-phosphorus-migrative [3 + 2] cycloaddition in the presence of a proton source under photocatalytic conditions. The reaction exhibits broad functional group tolerance and affords substituted cyclic phosphonium salts, which are amenable to further derivatization by Wittig olefination. Theoretical studies suggest that the phosphorus 1,2-migration of a ß-phosphonioalkyl radical proceeds through a phosphine radical cation-alkene complex as a pseudointermediate, and the two fragments in the intermediate are bound to each other through multiple noncovalent interactions.

15.
Chemistry ; 29(60): e202301993, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37581259

RESUMO

Controlled self-assembly of PtII complexes is key to the development of optical and stimuli-responsive materials, but designing and precisely controlling them is still difficult owing to weak intermolecular interactions. Herein, we report the successful water-vapor-induced assembly of an anionic PtII complex [Pt(CN)2 (ppy)]- (Hppy=2-phenylpyridine) electrostatically loaded onto cationically charged layered double hydroxide (LDH) nanoparticles consisting of Mg2+ and Al3+ ions. When the PtII complexes were densely loaded onto the LDH nanoparticles, the assembly was maintained, even in dilute aqueous media. In the case of sparse loading, the PtII complexes were loaded discretely in the dry state; however, when water vapor was adsorbed, the increased mobility of the PtII complexes led to their assembly on the LDH nanoparticles. The presence of water vapor led to a drastic change in luminescence from green to orange.

16.
Pediatr Infect Dis J ; 42(9): 766-773, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37257096

RESUMO

BACKGROUND: Many reports have reported a reduction in respiratory infectious diseases and infectious gastroenteritis immediately after the coronavirus disease 2019 (COVID-19) pandemic, but data continuing into 2022 are very limited. We sought to understand the current situation of various infectious diseases among children in Japan as of July 2022 to improve public health in the post-COVID-19 era. METHODS: We collected data on children hospitalized with infectious diseases in 18 hospitals in Japan from July 2019 to June 2022. RESULTS: In total, 3417 patients were hospitalized during the study period. Respiratory syncytial virus decreased drastically after COVID-19 spread in early 2020, and few patients were hospitalized for it from April 2020 to March 2021. However, an unexpected out-of-season re-emergence of respiratory syncytial virus was observed in August 2021 (50 patients per week), particularly prominent among older children 3-6 years old. A large epidemic of delayed norovirus gastroenteritis was observed in April 2021, suggesting that the nonpharmaceutical interventions for COVID-19 are less effective against norovirus. However, influenza, human metapneumovirus, Mycoplasma pneumoniae , and rotavirus gastroenteritis were rarely seen for more than 2 years. CONCLUSIONS: The incidence patterns of various infectious diseases in Japan have changed markedly since the beginning of the COVID-19 pandemic to the present. The epidemic pattern in the post-COVID-19 era is unpredictable and will require continued careful surveillance.


Assuntos
COVID-19 , Doenças Transmissíveis , Gastroenterite , Infecções Respiratórias , Criança , Humanos , Adolescente , Pré-Escolar , COVID-19/epidemiologia , Criança Hospitalizada , Pandemias , Japão/epidemiologia , Gastroenterite/epidemiologia , Doenças Transmissíveis/epidemiologia , Vírus Sinciciais Respiratórios , Infecções Respiratórias/epidemiologia
17.
Sensors (Basel) ; 23(9)2023 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-37177744

RESUMO

This study proposes a novel off-screen sound separation method based on audio-visual pre-training. In the field of audio-visual analysis, researchers have leveraged visual information for audio manipulation tasks, such as sound source separation. Although such audio manipulation tasks are based on correspondences between audio and video, these correspondences are not always established. Specifically, sounds coming from outside a screen have no audio-visual correspondences and thus interfere with conventional audio-visual learning. The proposed method separates such off-screen sounds based on their arrival directions using binaural audio, which provides us with three-dimensional sensation. Furthermore, we propose a new pre-training method that can consider the off-screen space and use the obtained representation to improve off-screen sound separation. Consequently, the proposed method can separate off-screen sounds irrespective of the direction from which they arrive. We conducted our evaluation using generated video data to circumvent the problem of difficulty in collecting ground truth for off-screen sounds. We confirmed the effectiveness of our methods through off-screen sound detection and separation tasks.

18.
Chem Commun (Camb) ; 59(44): 6745-6748, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37194401

RESUMO

A series of Pt(II) complexes bearing N-heterocyclic carbenes, [Pt(CN)2(Rim-Mepy)] (Rim-MepyH+ = 3-alkyl-1-(4-methyl-(2-pyridinyl))-1H-imidazolium, R = Me, Et, iPr, or tBu), exhibits triboluminescence in the visible range from blue to red, as well as the corresponding intense photoluminescence. Remarkably, among the complexes, the iPr-substituted one exhibits chromic triboluminescence behaviour during the process of rubbing and also vapour exposure.

19.
ACS Appl Mater Interfaces ; 15(22): 27277-27284, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37226704

RESUMO

Dye-sensitized H2 evolution photocatalysts have attracted considerable attention as promising systems for the photochemical generation of H2 from water. In this study, to mimic the reaction field of natural photosynthesis artificially, we synthesized a hydrophobic Ru(II) dye-sensitized Pt-TiO2 nanoparticle photocatalyst, RuC9@Pt-TiO2 (RuC9 = [Ru(dC9bpy)2(H4dmpbpy)]2+; dC9bpy = 4,4'-dinonyl-2,2'-bipyridine, H4dmpbpy = 4,4'-dimethyl phosphonic acid-2,2'-bipyridine), and integrated it into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayer vesicle membranes. The photocatalytic H2 production activity in 0.5 M l-ascorbic acid aqueous solution enhanced by more than three times in the presence of DPPC vesicles (apparent quantum yield = 2.11%), whereas such a significant enhancement was hardly observed when the vesicle formation was omitted. These results indicate that the highly dispersed state of the hydrophobic RuC9@Pt-TiO2 nanoparticles in the DPPC bilayer vesicles is a key factor in achieving enhanced photocatalytic H2 production activity in aqueous solution.

20.
Plant Cell Physiol ; 64(7): 803-813, 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37133246

RESUMO

Oleaginous microalgae are gaining great attention as feedstock for biofuels because of their substantial accumulation capacity for neutral lipids in the cytosolic compartment called the lipid droplet (LD). Understanding the regulatory mechanism of neutral lipid accumulation and degradation, which is mediated by LD-associated proteins, is an important issue in improving lipid productivity. However, LD-associated proteins vary among species and are waiting to be characterized in many microalgae. Stramenopile-type LD protein (StLDP) was previously identified as a primary LD protein in the marine diatom Phaeodactylum tricornutum. We produced a knockout mutant of StLDP by clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 genome editing. Also, we tried to complement this mutant by expressing recognition site-modified StLDP (RSM-StLDP), which is designed to avoid an attack by Cas9 nuclease expressing in the mutant. The RSM-StLDP:enhanced green fluorescent protein was localized to both LDs and the outer chloroplast-endoplasmic reticulum. The decrease in the LD number per cell, increase in LD size and no alteration of neutral lipid content in the mutant under nitrogen deficiency clearly indicate that StLDP acts as an LD scaffold protein. The number of LDs per cell increased in the complemented strain compared to wild-type (WT) cells. The LD morphology in the mutant is probably over-rescued in the complemented strain by the strong function of the nitrate reductase promoter, which is also supported by high neutral lipid content in the complemented strain. The growth of stldp mutant showed a long lag phase relative to WT cells, suggesting that the low surface-to-volume ratio of fused LD decreased the efficiency of LD hydrolysis during the initial growth phase.


Assuntos
Diatomáceas , Diatomáceas/genética , Diatomáceas/metabolismo , Gotículas Lipídicas/metabolismo , Proteínas Associadas a Gotículas Lipídicas/metabolismo , Edição de Genes , Lipídeos , Metabolismo dos Lipídeos/genética
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