ABSTRACT
To better understand the role of resting cysts in the outbreak of paralytic shellfish poisoning and bloom dynamics in Jinhae-Masan Bay, Korea, this study investigated the germination features of ellipsoidal Alexandrium cysts isolated from sediments collected in winter and summer under different combinations of temperature and salinity. Morphology and phylogeny of germling cells revealed that the ellipsoidal Alexandrium cysts belong to Alexandrium catenella (Group I). The cysts could germinate across a wide range of temperature (5-25 °C) with germination success within 5 days, indicating that continuous seeding for the maintenance of vegetative cells in the water column may occur through the year without an endogenous clock to regulate germination timing. In addition, the cyst germination of A. catenella (Group I) was not controlled by seasonal salinity changes. Based on the results, this study provides a schematic scenario of the bloom development of A. catenella (Group I) in Jinhae-Masan Bay, Korea.
Subject(s)
Cysts , Dinoflagellida , Shellfish Poisoning , Humans , Dinoflagellida/physiology , Temperature , Bays , Salinity , Republic of KoreaABSTRACT
Heptacodium miconioides is an increasingly popular ornamental plant, originally being endemic to China. The late and long flowering determines its ecological and ornamental value in cultivation. The aims of this research were to define and distinguish phenological phases of the development of Heptacodium miconioides in the temperate zone region and identification of anatomical changes within the stem during autumn in relation to phenological phases and climatic conditions. Phenological observations were carried out in Wroclaw during 2012-2013, as well as in Warsaw (Poland, 52.6°N, 20.5°E) during 2018-2021. During the last year of research an analysis of the anatomical structure was carried out for young stems that bore flowers that year, as well as older, 2- to 6-year-old ones. The material was collected H1 - 10.09., H2 - 28.09., H3 - 16.10., H4 - 3.11., H5 - 21.11. The width of annual increments in subsequent years was determined; length, width and vessel density in early and latewood for subsequent rings of annual growth was measured, as well as the width of the phloem in 1-6-year-old stems (2016-2021). In the vegetative stage three main stages of development were distinguished (leaf buds have the green tips; full autumn discoloration of leaves; leaves falling). In the generative phase, which lasted on average from August 22nd to January the 7th five main phases of development were distinguished (flowering, unripe fruits, ripe fruits, spreading of seeds). Increased average temperature during winter and spring had an effect on the growth pattern: early phenological stages occurred sooner and foliage development lasted 44 days longer. Flowering occurred at a similar date at both observed locations and climatic conditions. This year's shoots flowering on a radial section with axial symmetry, were slightly flattened and in clusters arranged regularly to match the shape. Heptacodium develops 2-6 years old shoots with radial symmetry. The growth ring boundaries are distinct, the wood semi-rings porous, with marked differences in the structure of the primary and secondary shoot. Lignification of tissues before winter ends during late leaf-fall phase. The research indicated the adaptive potential of Heptacodium in response to climatic conditions of temperate zone.
Subject(s)
Flowers , Plant Leaves , Poland , Seasons , Plant Leaves/physiology , Plants , Temperature , Climate ChangeABSTRACT
Objective: To examine the stem cell-like properties of dormant cells in ovarian epithelial carcinoma transplantation tumors. Methods: The PKH26-labeled human ovarian cancer SKOV3 cells were inoculated subcutaneously in nude mice. According to the fluorescence intensity of PKH2, the tumor cells were divided into 3 groups using FCM method: PKH26 cells with high fluorescence retention (PKH26hi cells), PKH26 cells with low fluorescence retention (PKH26low cells), and PKH26 cells with fluorescence quenched completely (PKH26neg cells). The cell cycle of PKH26hi, PKH26low and PKH26neg SKOV3 cells was detected by FCM method. The mRNAs and proteins of stem cell markers octamer-binding protein 3/4 (OCT3/4), CD1 33, CD1 77 and Nanog were examined by real-time fluorescence-based quantitative PCR and Western blotting. The colony forming ability of PKH26hi, PKH26low and PKH26neg SKOV3 cells in vitro was observed by plate colony formation assay, and the tumorigenic ability in vivo was observed in nude mice. Results: The percentage of G0/G1 cells in PKH26hi SKOV3 cells was higher than those in PKH26low and PKH26neg cells (both P < 0.05). The mRNA and protein expression levels of stem cell markers OCT3/4, CD1 33, CD1 1 7 and Nanog in PKH26hi were higher than those in PKH26low and PKH26neg SKOV3 cells (all P < 0.05). The abilities of in vitro colony formation of PKH26hi SKOV3 cells and their tumorigenesis in nude mice were significantly higher than those of PKH26low cells and PKH26neg SKOV3 cells (both P < 0.05). Conclusion: PKH26hi cells in ovarian cancer SKOV3 cell xenografts in nude mice have stem cell-like properties.
ABSTRACT
Prior to the formation of new metastases,a large number of cancer cells released from the primary tumor enter the dormancy period.Once the dorruancy is broken,tumor cells will recover the capability of proliferation.In recent years,various hypotheses and mechanisms of tumor metastasis have been studied.Primary tumor resection is considered to be an important factor to break tumor dormancy state.It is recognized as an important reason to promote tumor metastasis.The improvement of surgical technique and further study on the mechanism of dormancy may provide new ideas for the treatment of metastatic tumor.
ABSTRACT
Tumor dormancy is a phase of occurrence and progress of cancer.In recent years,with the further study of circulating tumor cells,disseminated tumor cells and cancer stem cells,it is found that they are closely related to the tumor dormancy.Moreover,tumor microenvironment is another important factor in tumor dormancy.
ABSTRACT
Tumor dormancy is a state that tumor cells long-term exist in human body,without obvious growth. Dormant cell is one of the origins of tumor recurrence or metastasis. The exact mechanism of tumor dor-mancy is still unclear. Combined with cellular and molecular biological techniques,tumor cell transplantation and culture in vitro can establish experimental tumor dormancy-recurrence models. These in vivo and in vitro models can be used to investigate mechanisms of tumor dormancy and to explore novel treatments.