New record of ten ciliate species (Protozoa, Ciliophora) from South Korea

Atef Omar,최지혜,정재호 국립생물자원관 2023 Journal of species research Vol.12 No.1

Ciliates are unicellular eukaryotes and one of the most abundant and speciose protistan groups. However, their diversity is underestimated, and many new species are waiting for our discovery. During several field surveys conducted from 2018 to 2021 to document indigenous Korean ciliates, 10 unrecorded ciliate species were collected and investigated from freshwater, marine, and semiterrestrial habitats. The morphology of these species was studied based on observation of living and protargol-stained specimens. These species belong to five classes as follows: 1) class Heterotrichea - Peritromus faurei; 2) class Spirotrichea - Heterotachysoma dragescoi, Pseudokeronopsis parasongi, and Certesia quadrinucleata; 3) class Nassophorea - Chilodontopsis depressa; 4) class Prostomatea - Plagiocampa rouxi and Urotricha furcata; and 5) class Oligohymenophorea - Metanophrys similis, Uronema gallicum, and Protocyclidium citrullus. Also, we provide a brief diagnosis, photomicrographs, and information of the locality for each species. Further, we compare each species with the most recent description and with similar congeners.

New record of 21 ciliate species(Protozoa, Ciliophora) from South Korea

Omar, Atef,Jung, Jae-Ho The National Institute of Biological Resources 2021 Journal of species research Vol.10 No.3

During a field survey of indigenous Korean ciliates, we collected 21 unrecorded species from aquatic (freshwater and brackish water [salinity about 1.0‰] samples) and terrestrial(moss and soil samples) habitats. The morphology of these species was studied based on live observation, protargol, silver carbonate and silver nitrate impregnation, and scanning electron microscope. These species belong to seven classes as follows: 1) class Heterotrichea - Blepharisma seculum; 2) class Spirotrichea - Birojimia terricola, Bistichella variabilis, Deviata bacilliformis, Oxytricha paragranulifera, Parabistichella cf. variabilis, Steinia sphagnicola, Stichotricha aculeata, Stylonychia cf. notophora, and Tetmemena bifaria minima; 3) class Armophorea - Metopus es; 4) class Litostomatea - Acropisthium mutabile, Pseudomonilicaryon japonicum, and Rimaleptus alpinus; 5) class Phyllopharyngea - Podophrya bivacuolata; 6) class Nassophorea - Drepanomonas pauciciliata; and 7) class Oligohymenophorea - Dexiostoma campylum, Frontonia atra, Histiobalantium natans viridis, Opisthonecta minima, and Tetrahymena rostrata. Here, we provide a brief diagnosis and remark for each species.

New record of five anaerobic ciliate species from South Korea

OMAR ATEF ISMAIL MOHAMED,정재호 국립생물자원관 2022 Journal of species research Vol.11 No.2

During a field survey to report unrecorded Korean ciliates, we collected five anaerobic ciliate species in two samples from freshwater and marine environments. These species belong to the classes Armophorea and Plagiopylea. The morphology of these species was studied based on live observations, protargol impregnation, and scanning electron microscope. Brachonella contorta is characterized by a size of 80- 100×40-60 μm in vivo, a bullet-shaped body, and about 60 oral polykinetids making 360° spiral around long axis. Brachonella pulchra is characterized by a size of 80-110×50-70 μm in vivo and adoral zone composed of about 40 oral polykinetids with minimal spiralization. Metopus setosus is characterized by a size of 45-70×20-30 μm in vivo, about 22 ciliary rows, very long caudal cilia, and 20 oral polykinetids. Plagiopyla nasuta is a freshwater species characterized by a size of 80-120×50-60 μm in vivo, striated band present, straight extrusomes, and about 70 somatic ciliary rows. The marine Plagiopyla frontata is characterized by a size of 80-120×40-60 μm in vivo, an oval to ellipsoid body shape, 50-60 somatic ciliary rows, and curved extrusomes.

New Record of Three Marine Ciliates (Protozoa, Ciliophora) from South Korea

Atef Omar,문지혜,정재호 한국동물분류학회 2023 Animal Systematics, Evolution and Diversity Vol.39 No.1

During a field survey of Korean marine ciliates, we collected three ciliate species from the eastern coastal waters of the Yellow Sea. Based on the observation of living and protargol and wet silver nitrate stained cells, the ciliates, belonging to the classes Spirotrichea and Oligohymenophorea, were identified as Cardiostomatella vermiformis (Kahl, 1928) Corliss, 1960, Parallelostrombidium paraellipticum Song et al., 2018, and Pleuronema paucisaetosum Pan et al., 2015. Both Parallelostrombidium paraellipticum and Pleuronema paucisaetosum were described only from their type localities, i.e., brackish water, suggesting that they tolerate a broad range of salinity, while Cardiostomatella is marine ciliate and seems to be cosmopolitan. These three species were reported for the first time in Korea. Brief descriptions, remarks to justify their identity and to compare the present isolates with similar taxa, and photomicrographs were provided for the three species.

Survival and Prognostic Factors for Hepatocellular Carcinoma: an Egyptian Multidisciplinary Clinic Experience

Abdelaziz, Ashraf Omar,Elbaz, Tamer Mahmoud,Shousha, Hend Ibrahim,Ibrahim, Mostafa Mohamed,El-Shazli, Mostafa Abdel Rahman,Abdelmaksoud, Ahmed Hosni,Aziz, Omar Abdel,Zaki, Hisham Atef,Elattar, Inas An Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

Background: Hepatocellular carcinoma (HCC) is a dismal tumor with a high incidence, prevalence and poor prognosis and survival. Management of HCC necessitates multidisciplinary clinics due to the wide heterogeneity in its presentation, different therapeutic options, variable biologic behavior and background presence of chronic liver disease. We studied the different prognostic factors that affected survival of our patients to improve future HCC management and patient survival. Materials and Methods: This study is performed in a specialized multidisciplinary clinic for HCC in Kasr El Eini Hospital, Cairo University, Egypt. We retrospectively analyzed the different patient and tumor characteristics and the primary mode of management applied to our patients. Further analysis was performed using univariate and multivariate statistics. Results: During the period February 2009 till February 2013, 290 HCC patients presented to our multidisciplinary clinic. They were predominantly males and the mean age was $56.5{\pm}7.7years$. All cases developed HCC on top of cirrhosis that was mainly due to HCV (71%). Most of our patients were Child-Pugh A (50%) or B (36.9%) and commonly presented with small single lesions. Transarterial chemoembolization was the most common line of treatment used (32.4%). The overall survival was 79.9% at 6 months, 54.5% at 1 year and 22.4% at 2 years. Serum bilirubin, site of the tumor and type of treatment were the significant independent prognostic factors for survival. Conclusions: Our main prognostic variables are the bilirubin level, the bilobar hepatic affection and the application of specific treatment (either curative or palliative). Multidisciplinary clinics enhance better HCC management.

The Effect of Corporate Social Responsibility Disclosure on Market Performance: Evidence from Jordan

Omar ZRAQAT,Qasim ZUREIGAT,Hani Ali AL-RAWASHDEH,Samer Mohammed OKOUR,Lina Fuad HUSSIEN,Atef Aqeel AL-BAWAB 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.8

The current study aims to investigate the relationship between CSRD and firm performance, as an indicator for corporate socially responsible behavior, and corporate market performance of listed companies on the Amman stock exchange (ASE). The study adopts a quantitative methodology and utilizes pooled data sets that was collected following content analysis approach of the annual reports for the period 2014 to 2019. The study sample consists of 42 listed companies. The study ran a multiple regression model in order to capture the relationship between the independent variable CSRD and the dependent variable that is Firm performance which was measured using Tobin’s Q. The study also utilized five control variables in order to control the hypothesized relationship between CSRD and Firm Performance. The results indicate a negative but significant relationship between CSRD and corporate market performance measured by Tobin’s Q. The results stand against the notion of the business case for CSR, and indicate the opposite position, so, the higher CSRD, the lower will be Tobin’s Q. Such results support the notion of the institutional theory, and provide an initial evidence for legitimacy seeking behavior in Jordanian companies. However, the results indicate a lower level of awareness of CSR across investors and market players, which support arguments of the difference in market perceptions towards CSR.

Molecular Characterization of Two Marine Tintinnids (Ciliophora, Spirotrichea, Tintinnidae) Using Six Genes

문지혜,OMAR ATEF ISMAIL MOHAMED,Pablo Quintela-Alonso,정재호 한국동물분류학회 2019 Animal Systematics, Evolution and Diversity Vol.35 No.4

DNA barcoding of two marine tintinnids, Eutintinnus rectus and Schmidingerella arcuata, was performed using four samples collected from different sites in the north-eastern coast of South Korea. The loricae morphology was observed by light and scanning electron microscopy. Molecular data were analyzed using five nuclear ribosomal DNA markers (18S, ITS1, 5.8S, ITS2, and 28S genes) and one mitochondrial marker (CO1 gene). The intraspecific pairwise differences of E. rectus and S. arcuata in the CO1 gene were 0.0-0.2% and 0.0-0.6%, respectively, while there were no differences in the 18S rDNA sequences.

Brief description of 18 newly recorded ciliate species from soil and inland waters (Protozoa, Ciliophora) in South Korea

김지혜,OMAR ATEF ISMAIL MOHAMED,정재호 국립생물자원관 2020 Journal of species research Vol.9 No.3

Ciliates are a speciose protozoan group and their diversity is still not well investigated in Korea. From our field surveys, 18 unrecorded ciliate species were collected from a total of nine localities in Korea. The field surveys were conducted in 2018 and 2019, and the unrecorded ciliates were found from terrestrial (moss and soil samples) and inland water (river and lagoon samples) habitats. The morphology of these ciliates was studied using the observation of living and silver impregnated (protargol) specimens. The present species belong to five classes as follows: 1) class Spirotrichea - Gonostomum kuehnelti, Quadristicha setigera, Lamtostyla decorata, L. islandica, L. longa, Anteholosticha brachysticha, Pseudobirojimia muscorum; 2) class Litostomatea - Apocoriplites lajacola, Epispathidium amphoriforme, Protospathidium muscicola, Phialinides australis, Paraenchelys wenzeli, Rimaleptus similis; 3) class Nassophorea - Drepanomonas revoluta; 4) class Colpodea - Bryometopus triquetrus; and 5) class Oligohymenophorea - Cyclidium glaucoma, Epistylis pygmaeum, Pseudovorticella vestita. The globular macronuclear nodules of P. vestita were observed for the first time in the Korean population.

New record of three Aspidisca species (Protozoa, Ciliophora) from South Korea

최지혜,Atef Omar,정재호 국립생물자원관 2023 Journal of species research Vol.12 No.1

The morphology and infraciliature of three newly recorded Aspidisca species in Korea, two collected from the eastern coast and one collected from Jeju Island, were investigated in vivo and after protargol impregnation. The three species are as follows: A. dentata Kahl, 1928, A. hexeris Quennerstedt, 1869, and A. polystyla Stein, 1859. The three species are characterized by having a “polystyla-arrangement” of frontoventral cirri: 1) A. dentata is characterized by having a broadly rotund body shape, a distinct peristomial spur, and a dorsal thorn; 2) A. hexeris is characterized by a broadly oval body shape, four projections along the left margin of body, and the single peristomial spur; and 3) A. polystyla has the broadly rotund body shape, transverse cirri each split into several parts (especially in vivo), and lacking of the peristomial spur. Among them, A. dentata and A. polystyla are poorly known and lack morphological description based on silver staining. In the present study, we provide a brief diagnosis, remarks, and photomicrographs.

New record of Pleuronema marinum Dujardin, 1841 (Protozoa, Ciliophora) from South Korea

여정현,최지혜,정재호,OMAR ATEF ISMAIL MOHAMED 국립생물자원관 2022 Journal of species research Vol.11 No.4

During a field survey of Korean marine ciliates, we collected Pleuronema marinum from a brackish water sample. It is characterized by the presence of a contractile vacuole in mid-body, rather than the subterminal/ terminal contractile vacuole as in other congeners. The cells were examined in vivo and based on protargol and ‘wet’ silver nitrate impregnation. In addition, the nuclear 18S rRNA gene was sequenced using a single cell. The Korean population morphologically and molecularly resembles a Chinese population of P. marinum. Historical review of the species concludes that 1) two or more species have been assigned into P. marinum, 2) the position of contractile vacuole (e.g., in mid-body) is a valid character state, and 3) P. marinum is probably a rare species. Here we provide a monographic treatment of P. marinum to clarify the issue and for further studies of relevant species. Considering there are about 40 nominal species and complex nomenclatural acts in the genus Pleuronema, further studies should provide descriptions based on protargol and ‘wet’ silver impregnation with marker gene(s).