• Title, Summary, Keyword: metazoans

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Targeting Cell-Cell and Cell-Matrix Interactions and Its Therapeutic Applications

  • Kim, In-San
    • Proceedings of the PSK Conference
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    • pp.100-101
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    • 2003
  • Cell-cell and cell-matrix interaction is clearly required for metazoans not only to hold their cells together but also to conduct more sophisticated biological processes. Each cell has adhesion molecules on its cell membrane to link extracellular matrix and adjacent cells to the intracellular cytoskeleton, and also to transduce signals. In complex metazoans, information is transmitted from one cell to another by mechanisms such as direct intercellular communication, soluble signal molecules among distant cells, and local cellular environments formed by highly specialized extracellular matrix. (omitted)

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Unrecorded species of Korean metazoans discovered through the project of "Discovery of Korean Indigenous Species" (2006-2010)

  • Song, Ji-Hun;Han, Yeong-Deok;Lee, Won-Koo;Kim, Il-Hoi;Paik, Sang-Gyu;Lee, Jongrak;Soh, Ho Young;Lee, Wonchoel;Jung, Jongwoo;Kim, Sa Heung;Lee, Jun-Sang;Kim, Joo-Pil;Park, Taeseo;Yoo, Jung-Sun;Kil, Hyun-Jong;Nam, Eunjung;Min, Gi-Sik
    • Journal of Species Research
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    • v.6 no.spc
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    • pp.164-171
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    • 2017
  • A research project entitled "Discovery of Korean Indigenous Species" was launched in 2006, and has been carried on as a continuous project until now. The main purpose of this project is to find undiscovered species on the Korean peninsula and ultimately register these species in the "National List of Species of Korea". In this paper, we present 79 unrecorded species of the Korean metazoans. All species were obtained from the final reports of "Discovery of Korean Indigenous Species" which were performed during the first five years of the project, 2006 to 2010.

Thrombolite reefs with archaeocyaths from the Xiannüdong Formation (Cambrian Series 2), Sichuan, China: implications for early Paleozoic bioconstruction

  • Zhang, Meiqi;Hong, Jongsun;Choh, Suk-Joo;Lee, Dong-Jin
    • Geosciences Journal
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    • v.21 no.5
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    • pp.655-666
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    • 2017
  • The early Cambrian incorporation of organisms with calcareous skeletons into microbial reefs initiated the metazoan bioconstructions of the Phanerozoic. Microbial reefs containing archaeocyaths from the middle early Cambrian $Xiann\ddot{u}dong$ Formation of the South China Block are investigated. The $Xiann\ddot{u}dong$ thrombolitic frameworks are composed primarily of Girvanella clumps and crusts, micritic clumps, and subordinate Epiphyton bundles. Amalgamated microbial frameworks contain sparse and rare (< 5%) archaeocyaths, with irregular archaeocyaths dominating the regular archaeocyaths by 6:1, and enclosed by Girvanella and other microbial elements. These $Xiann\ddot{u}dong$ thrombolitic reefs are broadly similar to other lower Cambrian thrombolitic reefs containing archaeocyaths, developed around shoals and lagoons. Similar thrombolitic reefs of the middle Cambrian from the Sino-Korean Block and Australia show reduced and increased contributions of Girvanella and Epiphyton, respectively, and the incorporation of lithistid and heteractinide sponges instead of archaeocyaths. These data suggest that the late early Cambrian decline of the archaeocyaths and their nearly instantaneous replacement by other metazoans allowed the continuance of microbial reefs with rare metazoans until the late Middle Ordovician shift in reef construction to metazoan reefs.

NDRG3-mediated lactate signaling in hypoxia

  • Park, Kyung Chan;Lee, Dong Chul;Yeom, Young Il
    • BMB Reports
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    • v.48 no.6
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    • pp.301-302
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    • 2015
  • Hypoxia is associated with many pathological conditions as well as the normal physiology of metazoans. We identified a lactate-dependent signaling pathway in hypoxia, mediated by the oxygen- and lactate-regulated protein NDRG family member 3 (NDRG3). Oxygen negatively regulates NDRG3 expression at the protein level via the PHD2/VHL system, whereas lactate, produced in excess under prolonged hypoxia, blocks its proteasomal degradation by binding to NDRG3. We also found that the stabilized NDRG3 protein promotes angiogenesis and cell growth under hypoxia by activating the Raf-ERK pathway. Inhibiting cellular lactate production abolishes NDRG3-mediated hypoxia responses. The NDRG3-Raf-ERK axis therefore provides the genetic basis for lactate-induced hypoxia signaling, which can be exploited for the development of therapies targeting hypoxia-induced diseases in addition to advancing our understanding of the normal physiology of hypoxia responses. [BMB Reports 2015; 48(6): 301-302]

A Review on Microbialites: a Korean Perspective (미생물암에 대하여: 한국적 관점)

  • Lee, Jeong-Hyun
    • The Journal of the Petrological Society of Korea
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    • v.24 no.4
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    • pp.291-305
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    • 2015
  • Microbialites are defined as rocks formed by microbial organisms. After their first appearance around 3.5 billion years ago, microbialites occur in various depositional environments throughout geological periods. Microbial organisms form microbialites by trapping and binding detrital sediments and/or precipitating carbonate cements, resulting in formation of various microstructures and mesostructures. Four major types of microbialites are distinguished based on their mesostructures: stromatolite, thrombolite, dendrolite, and leiolite. In the geological records, occurrences of microbialites are influenced by calcium carbonate saturation of seawater and interaction of microbialites with metazoans. Stromatolites mainly flourished during the Precambrian, and diminished as level of atmospheric carbon dioxide declined. On the other hand, thrombolites, mainly formed by calcified microbes, began to flourish from the Neoproterozoic. As metazoans diversified in the Phanerozoic, proportion of the microbialites within sedimentary record declined. Since then, microbialites only occasionally flourished during the Phanerozoic, such as shortly after mass-extinction events. In the Korean Peninsula, microbialites occur in the Neoproterozoic Sangwon System, the Early Paleozoic Joseon Supergroup, and the Cretaceous Gyeongsang Supergroup, which form different shapes according to their age and depositional environments. By performing detailed studies on these Korean microbialites, it is possible to understand how microbes affected geological records and sedimentary environments, as well as their interaction with other organisms.

Multi-level remodeling of transcriptional landscapes in aging and longevity

  • Lai, Rochelle W.;Lu, Ryan;Danthi, Prakroothi S.;Bravo, Juan I.;Goumba, Alexandre;Sampathkumar, Nirmal Kumar;Benayoun, Berenice A.
    • BMB Reports
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    • v.52 no.1
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    • pp.86-108
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    • 2019
  • In multi-cellular organisms, the control of gene expression is key not only for development, but also for adult cellular homeostasis, and gene expression has been observed to be deregulated with aging. In this review, we discuss the current knowledge on the transcriptional alterations that have been described to occur with age in metazoans. First, we discuss age-related transcriptional changes in protein-coding genes, the expected functional impact of such changes, and how known pro-longevity interventions impact these changes. Second, we discuss the changes and impact of emerging aspects of transcription in aging, including age-related changes in splicing, lncRNAs and circRNAs. Third, we discuss the changes and potential impact of transcription of transposable elements with aging. Fourth, we highlight small ncRNAs and their potential impact on the regulation of aging phenotypes. Understanding the aging transcriptome will be key to identify important regulatory targets, and ultimately slow-down or reverse aging and extend healthy lifespan in humans.

Cadmium-Induced Gene Expression is Regulated by MTF-1, a Key Metal- Responsive Transcription Factor

  • Gupta, Ronojoy-Sen;Ahnn, Joohong
    • Animal cells and systems
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    • v.7 no.3
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    • pp.173-186
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    • 2003
  • The transition metal cadmium is a serious occupational and environmental toxin. To inhibit cadmium-induced damage, cells respond by increasing the expression of genes that encode stress-responsive proteins. The metal-regulatory transcription factor 1 (MTF-1) is a key regulator of heavy-metal induced transcription of metallothionein-I and II and other genes in mammals and other metazoans. Transcriptional activation of genes by MTF-1 is mediated through binding to metal-responsive elements in the target gene promoters. Phosphorylation of MTF-1 plays a critical role in the cadmium-inducible transcriptional activation of metallothionein and other responses. Studies using inhibitors indicate that multiple kinases and signal transduction cascades, including those mediated by protein kinase C, tyrosine kinase and casein kinase II, are essential for cadmium-mediated transcriptional activation. In addition, calcium signaling is also involved in regulating metal-activated transcription. In several species, cadmium induces heat shock genes. Recently much progress has been made in elucidating the cellular machinery that regulates this metal-inducible gene expression. This review summarizes these recent advances in understanding the role of some known cadmium-responsive genes and the molecular mechanisms that activate metal-responsive transcription factor, MTF-1.

A novel model of THO/TREX loading onto target RNAs in metazoan gene expression

  • Hur, Junho K.;Chung, Yun Doo
    • BMB Reports
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    • v.49 no.7
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    • pp.355-356
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    • 2016
  • The THO/TREX complex consists of several conserved subunits and is required for mRNA export. In metazoans, THO/TREX binds a subset of mRNAs during RNA splicing, and facilitates their nuclear export. How THO/TREX selects RNA targets is, however, incompletely understood. In our recent study, we reported that THO is loaded onto Piwi-interacting RNA (piRNA) precursor transcripts independent of splicing, and facilitates convergent transcription in Drosophila ovary. The precursors are later processed into mature piRNAs, small noncoding RNAs that silence transposable elements (TEs). We observed that piRNAs originating from dual-strand clusters, where precursors are transcribed from both strands, were specifically affected by THO mutation. Analysis of THO-bound RNAs showed enrichment of dual-strand cluster transcripts. Interestingly, THO loading onto piRNA precursors was dependent on Cutoff (Cuff), which comprises the Rhino-Deadlock-Cutoff (RDC) complex that is recruited to dual-strand clusters by recognizing H3K9me3 and licenses convergent transcription from he cluster. We also found that THO mutation affected transcription from dual-strand clusters. Therefore, we concluded that THO/TREX is recruited to dual-strand piRNA clusters, independent of splicing events, via multi-protein interactions with chromatin structure. Then, it facilitates transcription likely by suppressing premature termination to ensure adequate expression of piRNA precursors.

Grazing on Bacteria and Algae by Metazoans in the Lake-river Ecosystem (River Spree, Germany)

  • Kim, Hyun-Woo;Joo, Gea-Jae;Walz, Norbert
    • Korean Journal of Ecology and Environment
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    • v.41 no.1
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    • pp.111-115
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    • 2008
  • Direct effects of zooplankton grazing activities on the natural assemblage of bacterioplankton and algae were evaluated at monthly intervals, from June to October of 2000, in the middle part of the River Spree, Germany. We quantified bacterioplankton, algae, zooplankton abundance and measured carbon ingestion rates (CIRs) by zooplankton according to two zooplankton size classes: (i) micro zooplankton (MICZ), ranging in size from 30 to $150{\mu}m$ and including rotifers and nauplii, excluding protozoans and (ii) macrozooplankton (MACZ), larger than $150{\mu}m$ and including cladocerans and copepods. CIRs were measured using natural bacterial and algae communities in the zooplankton density manipulation experiments. Algae biomass (average${\pm}$SD: $377{\pm}306{\mu}gC\;L^{-1}$, n=5) was always higher than bacterial biomass ($36.7{\pm}9.9{\mu}gC\;L^{-1}$, n=5). Total zooplankton biomass varied from 19.8 to $137{\mu}gC\;L^{-1}$. Total mean biomass of zooplankton was $59.9{\pm}52.5{\mu}gC\;L^{-1}$ (average${\pm}$SD, n=5). Average MICZ biomass ($40.2{\pm}47.6{\mu}gC\;L^{-1}$ n=5) was nearly twofold higher than MACZ biomass ($19.6{\pm}20.6{\mu}gC\;L^{-1}$ n=5). Total zooplankton CIRs on algae (average${\pm}$SD: $56.6{\pm}26.4{\mu}gC\;L^{-1}\;day^{-1}$) were $\sim$fourfold higher than that on bacteria $(12.7{\pm}6.0{\mu}gC\;L^{-1}\;day^{-1})$. MICZ CIRs on bacteria $(7.0{\pm}2.8{\mu}gC\;L^{-1}\;day^{-1})$ and algae $(28.6{\pm}20.6{\mu}gC\;L^{-1}\;day^{-1})$ were slightly higher than MACZ CIRs. On average, MICZ accounted for 55.6 and 50.5% of total zooplankton grazing on bacteria and algae, respectively. Considering the MICZ and MACZ CIRs, the relative role of transferring carbon to higher trophic levels were nearly similar between both communities in the lake-river ecosystem.

Functional Analysis of the Putative BUB2 Homologues of C. elegans in the Spindle Position Checkpoint

  • Lee, Kyung-Hee;Song, Ki-Won
    • Animal cells and systems
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    • v.9 no.2
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    • pp.87-94
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    • 2005
  • Spindle position checkpoint monitors the orientation of mitotic spindle for proper segregation of replicated chromosomes into mother cell and the daughter, and prohibits mitotic exit when mitotic spindle is misaligned. BUB2 forms one of the key upstream element of spindle position checkpoint in budding yeast, but its functional homologues have not been identified in higher eukaryotes. Here, we analyzed the functions of two putative BUB2 homologues of C. elegans in the spindle orientation checkpoint. From the C. elegans genome database, we found that two open reading frames (ORFs), F35H12_2 and C33F10_2, showed high sequence homology with BUB2. We obtained the expressed sequence tag (EST) clones for F35H12_2 (yk221d4) and C33F10_2 (yk14e10) and verified the full cDNA for each ORF by sequencing and 5' RACE with SL1 primer. The functional complementation assays of yk221d4 and yk14e10 in ${\Delta}bub2$ of S. cerevisiae revealed that these putative BUB2 homologues of C. elegans could not replace the function of BUB2 in spindle position checkpoint and mitotic exit. Our attempt to document the component of spindle position checkpoint in metazoans using sequence homology was not successful. This suggests that structural information about its components might be required to identify functional homologues of the spindle position checkpoint in higher eukaryotes.