Histone modification and nucleosome assembly play important roles in chromatin-related processes.Histone chaperones form different complexes and coordinate histone transportation and assembly.Various histone chaperone...Histone modification and nucleosome assembly play important roles in chromatin-related processes.Histone chaperones form different complexes and coordinate histone transportation and assembly.Various histone chaperone complexes have been identified in different organisms.The ciliate protozoa(ciliates)have various chromatin structures and different nuclear morphology.However,histone chaperone components and functions of different subunits remain unclear in ciliates.Tet-rahymema thermophila contains a transcriptionally active macronucleus(MAC)and a transcriptionally inactive micronu-cleus(MIC)which exhibit multiple replication and various chromatin remodeling progresses during vegetative growth and sexual developmental stages.Here,we found histone chaperone RebL1 not only localized evenly in the transcriptionally active MAC but also dynamically changed in the MIC during vegetative growth and sexual developmental stages.REBL1 knockdown inhibited cellular proliferation.The macronuclear morphology became bigger in growing mutants.The abnormal macronuclear structure also occurred in the starvation stage.Furthermore,micronuclear meiosis was disturbed during sexual development,leading to a failure to generate new gametic nuclei.RebL1 potentially interacted with various factors involved in histone-modifying complexes and chromatin remodeling complexes in different developmental stages.REBL1 knockdown affected expression levels of the genes involved in chromatin organization and transcription.Taken together,RebL1 plays a vital role in maintaining macronuclear structure stability and gametogenesis in T.thermophila.展开更多
There exist a large class of acoustic sources which have an underlying periodic phenomenon. Unlike the well-studied Bearings-Only Tracking(BOT) of an aperiodic acoustic source,this paper considers the problem of track...There exist a large class of acoustic sources which have an underlying periodic phenomenon. Unlike the well-studied Bearings-Only Tracking(BOT) of an aperiodic acoustic source,this paper considers the problem of tracking a periodic acoustic source. For periodic acoustic tracking, the signal emission time is known. However, the true measurement reception time is unknown because it is corrupted by noise due to propagation delay. We augment the sensor’s signal reception time onto bearing measurements, and the information of the delay constraint is included in the original bearing measurements to compensate for the propagation delay. A Cubature Kalman Filter(CKF) is used for periodic acoustic source tracking, in which measurement prediction cannot be obtained directly because the sensor’s position at the true measurement reception time is unknown.We solve this problem by using the implicit Gauss-Helmert Sensor Model(GHSM) for estimating the sensor’s position, which consists of the sensor’s motion equation and the known measured sensor’s signal reception time equation related to the state. Then a CKF based on the GHSM(CF-GHSM) is developed for periodic acoustic tracking. Illustrative examples demonstrate that the CF-GHSM algorithm is better than other algorithms for periodic acoustic source tracking.展开更多
基金supported by the National Natural Science Foundation of China(32270450,32071449)Shanxi Key Program International S&T Cooperation Projects(202104041101011)Shanxi Scholarship Council of China(2020016).
文摘Histone modification and nucleosome assembly play important roles in chromatin-related processes.Histone chaperones form different complexes and coordinate histone transportation and assembly.Various histone chaperone complexes have been identified in different organisms.The ciliate protozoa(ciliates)have various chromatin structures and different nuclear morphology.However,histone chaperone components and functions of different subunits remain unclear in ciliates.Tet-rahymema thermophila contains a transcriptionally active macronucleus(MAC)and a transcriptionally inactive micronu-cleus(MIC)which exhibit multiple replication and various chromatin remodeling progresses during vegetative growth and sexual developmental stages.Here,we found histone chaperone RebL1 not only localized evenly in the transcriptionally active MAC but also dynamically changed in the MIC during vegetative growth and sexual developmental stages.REBL1 knockdown inhibited cellular proliferation.The macronuclear morphology became bigger in growing mutants.The abnormal macronuclear structure also occurred in the starvation stage.Furthermore,micronuclear meiosis was disturbed during sexual development,leading to a failure to generate new gametic nuclei.RebL1 potentially interacted with various factors involved in histone-modifying complexes and chromatin remodeling complexes in different developmental stages.REBL1 knockdown affected expression levels of the genes involved in chromatin organization and transcription.Taken together,RebL1 plays a vital role in maintaining macronuclear structure stability and gametogenesis in T.thermophila.
基金supported in part by the National Key Research and Development Plan,China(No.2017YFB1301101)the National Natural Science Foundation of China(Nos.61673317 and 61673313)。
文摘There exist a large class of acoustic sources which have an underlying periodic phenomenon. Unlike the well-studied Bearings-Only Tracking(BOT) of an aperiodic acoustic source,this paper considers the problem of tracking a periodic acoustic source. For periodic acoustic tracking, the signal emission time is known. However, the true measurement reception time is unknown because it is corrupted by noise due to propagation delay. We augment the sensor’s signal reception time onto bearing measurements, and the information of the delay constraint is included in the original bearing measurements to compensate for the propagation delay. A Cubature Kalman Filter(CKF) is used for periodic acoustic source tracking, in which measurement prediction cannot be obtained directly because the sensor’s position at the true measurement reception time is unknown.We solve this problem by using the implicit Gauss-Helmert Sensor Model(GHSM) for estimating the sensor’s position, which consists of the sensor’s motion equation and the known measured sensor’s signal reception time equation related to the state. Then a CKF based on the GHSM(CF-GHSM) is developed for periodic acoustic tracking. Illustrative examples demonstrate that the CF-GHSM algorithm is better than other algorithms for periodic acoustic source tracking.
