Daeryul Kwon, Keonhee Kim, Hyunjin Jo, Sang Deuk Lee, Suk Min Yun, Chaehong Park
{"title":"Environmental factors affecting akinete germination and resting cell awakening of two cyanobacteria","authors":"Daeryul Kwon, Keonhee Kim, Hyunjin Jo, Sang Deuk Lee, Suk Min Yun, Chaehong Park","doi":"10.1186/s42649-023-00085-6","DOIUrl":"10.1186/s42649-023-00085-6","url":null,"abstract":"<div><p>Globally, cyanobacteria frequently cause blooms that outcompete other species in the waterbody, affecting the diversity, decreasing water exchange rates, and promoting eutrophication that leads to excessive algal growth. Here, <i>Dolichospermum circinale</i> (akinetes) and <i>Microcystic aeruginosa</i> (resting cells), were isolated from the sediment in the Uiam Dam in the North Han River and near Ugok Bridge in the Nakdong River, respectively. The morphology, germination process and rates, and growth was evaluated in different environmental conditions. <i>D. cercinalis</i> germination began on day two of culturing, with maximum cell growth observed on day ten. In contrast, <i>M. aeruginosa</i> exhibited daily increase in cell density and colony size, with notable density increase on day six. Next, different environmental conditions were assessed. Akinetes exhibited high germination rates at low light intensity (5—30 µmol/m<sup>2</sup>/s), whereas resting cells exhibited high growth rates at high light intensity (50—100 µmol/m<sup>2</sup>/s). Furthermore, both cell types exhibited optimum germination and growth in media containing N and P at 20—30° at a pH of 7—9. Our study reveals the optimum conditions for the germination and growth of cyanobacterial akinetes and resting cells isolated from river sediment, respectively, and will assist in predicting cyanobacterial blooms for appropriate management.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://appmicro.springeropen.com/counter/pdf/10.1186/s42649-023-00085-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4679627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Changes of lysosome by L-serine in rotenone-treated hippocampal neurons","authors":"Sumin Shin, Su-Kyeong Hwang, Ji Young Mun","doi":"10.1186/s42649-022-00084-z","DOIUrl":"10.1186/s42649-022-00084-z","url":null,"abstract":"<div><p>Oxidative stress destroys cellular organelles and damages DNA, eventually leading to degenerative brain disorders. Persistent mitochondrial damage by oxidative stress eventually causes cells to inhibit the function of lysosomes. Rotenone used in this study inhibits complex 1 of the mitochondrial electron transport chain. Due to this inhibition, the production of free radicals is promoted, and oxidative stress can occur. To test as a role of antioxidant, L-serine was treated before treatment of rotenone to HT22 hippocampal cells. Then, changes in the activity and structure of lysosomes were analyzed. As a result, the oxidative stress caused by rotenone in HT22 cells was protected by L-serine. L-serine reduced free radicals in cells, and the damaged lysosomal structure and lysosome activity were also protected.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://appmicro.springeropen.com/counter/pdf/10.1186/s42649-022-00084-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4419628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yoon-Uk Heo, Chang-Gon Jeong, Soo-Hyun Kim, Gun-Young Yoon, T. T. T. Trang, Youngyun Woo, Eun Yoo Yoon, Young-Seon Lee
{"title":"EPMA quantification on the chemical composition of retained austenite in a Fe-Mn-Si-C-based multi-phase steel","authors":"Yoon-Uk Heo, Chang-Gon Jeong, Soo-Hyun Kim, Gun-Young Yoon, T. T. T. Trang, Youngyun Woo, Eun Yoo Yoon, Young-Seon Lee","doi":"10.1186/s42649-022-00083-0","DOIUrl":"10.1186/s42649-022-00083-0","url":null,"abstract":"<div><p>An electron probe X-ray microanalyzer (EPMA) is an essential tool for studying chemical composition distribution in the microstructure. Quantifying chemical composition using standard specimens is commonly used to determine the composition of individual phases. However, the local difference in chemical composition in the standard specimens brings the deviation of the quantified composition from the actual one. This study introduces how to overcome the error of quantification in EPMA in the practical aspect. The obtained results are applied to evaluate the chemical composition of retained austenite in multi-phase steel. Film-type austenite shows higher carbon content than blocky-type one. The measured carbon contents of the retained austenite show good coherency with the calculated value from the X-ray diffraction.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9768052/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10768149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Histological study on the skin structure in two mudskippers, Periophthalmus waltoni and Boleophthalmus dussumieri in relation to their terrestrial life","authors":"Mehran Dorostghoal, Ashraf Jazayeri, Sara Ashiri","doi":"10.1186/s42649-022-00081-2","DOIUrl":"10.1186/s42649-022-00081-2","url":null,"abstract":"<div><p>Microscopic structure of skin in two amphibious mudskipper fish; <i>Boleophthalmus dussumieri</i> Valenciennes, 1837 (<i>B. dussumeri</i>) and <i>Periophthalmus waltoni</i> Koumans, 1941 <i>(P. waltoni)</i> were investigated in relation to their lifestyle. The general structure of skin is the same among the two species. Epidermis in <i>B. dussumeri</i> was thicker significantly than <i>P. waltoni</i>. The dermal bulges were only well developed in the skin of <i>B. dussumeri</i>. Mucous cells were absent in the epidermis of <i>P. waltoni</i> but present in <i>B. dussumeri</i>. Both <i>B. dussumeri</i> and <i>P. waltoni</i> have well-developed swollen middle cells as a shared epidermal feature. The thickness of the middle cell layer of the epidermis in <i>B. dussumeri</i> was significantly greater than in <i>P. waltoni</i>. Capillaries in the dorsal and ventral parts of the body are more closely distributed to the epidermal surface in <i>P. waltoni</i> than in <i>B. dussumeri</i>. The diffusion distance in the dorsal epidermis of <i>P. waltoni</i> was less than that in the ventral epidermis of <i>B. dussumeri</i>. A comparative examination of the skin of mudskipper species suggests that, due to the more terrestrial lifestyle adopted by <i>P. waltoni</i>, the skin contributes more to respiration.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9756237/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10748758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mi Kyung Bok, Chung Hwa Chin, Hee Jung Choi, Ju Hyun Ham, Byung Soo Chang
{"title":"Analysis of composition and microstructure of diatom frustules in mud on the coast of Boryeong- city, South Korea","authors":"Mi Kyung Bok, Chung Hwa Chin, Hee Jung Choi, Ju Hyun Ham, Byung Soo Chang","doi":"10.1186/s42649-022-00082-1","DOIUrl":"10.1186/s42649-022-00082-1","url":null,"abstract":"<div><p>The microstructure of diatom frustules found in mud sediments along the coast of Boryeong- city, South Korea, was observed using a scanning electron microscopy (SEM), and the constituent elements of diatoms were analyzed using energy<b>-</b>dispersive X-ray spectroscopy (EDS). Diatom frustules and clay minerals were present in the SEM images of the mud powder. High-magnification SEM images revealed that the surface of the frustules contained identically shaped circular pores, measuring 1 μm in diameter, arranged at regular intervals. This study revealed that the diatom shell fragments in the mud powder ranged in size from 3 to 30 μm, with an average thickness of approximately 2.5 μm. The elements Si, Al, Fe, K, Na, Mg, and Ti were detected while analyzing the frustule constituents, with Si being the primary component with the highest content.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9755392/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10732718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Poxvirus under the eyes of electron microscope","authors":"Jaekyung Hyun","doi":"10.1186/s42649-022-00080-3","DOIUrl":"10.1186/s42649-022-00080-3","url":null,"abstract":"<div><p>Zoonotic poxvirus infections pose significant threat to human health as we have witnessed recent spread of monkeypox. Therefore, insights into molecular mechanism behind poxvirus replication cycle are needed for the development of efficient antiviral strategies. Virion assembly is one of the key steps that determine the fate of replicating poxviruses. However, in-depth understanding of poxvirus assembly is challenging due to the complex nature of multi-step morphogenesis and heterogeneous virion structures. Despite these challenges, decades of research have revealed virion morphologies at various maturation stages, critical protein components and interactions with host cell compartments. Transmission electron microscopy has been employed as an indispensable tool for the examination of virion morphology, and more recently for the structure determination of protein complexes. In this review, we describe some of the major findings in poxvirus morphogenesis and the contributions of continuously advancing electron microscopy techniques.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9659681/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40683987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Ishtiaq, Aqil Inam, Saurabh Tiwari, Jae Bok Seol
{"title":"Microstructural, mechanical, and electrochemical analysis of carbon doped AISI carbon steels","authors":"Muhammad Ishtiaq, Aqil Inam, Saurabh Tiwari, Jae Bok Seol","doi":"10.1186/s42649-022-00079-w","DOIUrl":"10.1186/s42649-022-00079-w","url":null,"abstract":"<div><p>The effect of carbon doping contents on the microstructure, hardness, and corrosion properties of heat-treated AISI steel grades of plain carbon steel was investigated in this study. Various microstructures including coarse ferrite-pearlite, fine ferrite-pearlite, martensite, and bainite were developed by different heat treatments i.e. annealing, normalizing, quenching, and austempering, respectively. The developed microstructures, micro-hardness, and corrosion properties were investigated by a light optical microscope, scanning electron microscope, electromechanical (Vickers Hardness tester), and electrochemical (Gamry Potentiostat) equipment, respectively. The highest corrosion rates were observed in bainitic microstructures (2.68–12.12 mpy), whereas the lowest were found in the fine ferritic-pearlitic microstructures (1.57–6.36 mpy). A direct correlation has been observed between carbon concentration and corrosion rate, i.e. carbon content resulted in an increase in corrosion rate (2.37 mpy for AISI 1020 to 9.67 mpy for AISI 1050 in annealed condition).</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9583967/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40657667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Review on the structural understanding of the 10S myosin II in the era of Cryo-electron microscopy","authors":"Anahita Vispi Bharda, Hyun Suk Jung","doi":"10.1186/s42649-022-00078-x","DOIUrl":"10.1186/s42649-022-00078-x","url":null,"abstract":"<div><p>The compact smooth muscle 10S myosin II is a type of a monomer with folded tail and the heads bending back to interact with each other. This inactivated form is associated with regulatory and enzymatic activities affecting myosin processivity with actin filaments as well as ATPase activity. Phosphorylation by RLC can however, shuttle myosin from the inhibited 10S state to an activated 6S state, dictating the equilibrium. Multiple studies contributed by TEM have provided insights in the structural understanding of the 10S form. However, it is only recently that the true potential of Cryo-EM in deciphering the intramolecular interactions of 10S myosin state has been realized. This has led to an influx of new revelations on the 10S inactivation, unfolding mechanism and association in various diseases. This study reviews the gradual development in the structural interpretation of 10S species from TEM to Cryo-EM era. Furthermore, we discuss the utility of Cryo-EM in future myosin 10S studies and its contribution to human health.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9550946/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33497602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Histology and morphometry of the skin of the trident goby Tridentiger brevispinis (Perciformes, Gobiidae)","authors":"Hyun-Tae Kim","doi":"10.1186/s42649-022-00077-y","DOIUrl":"10.1186/s42649-022-00077-y","url":null,"abstract":"<div><p>The Korean trident goby, <i>Tridentiger brevispinis</i>, lives in adverse habitats that can easily become hypoxic due to low precipitation, regional dry periods, and high amounts of solar radiation. Histological and morphometric studies revealed the goby’s specialized skin (35.4–150.0 μm in thickness), consisting of an epidermis and dermis. The thicker epidermis comprises an outermost surface layer (having taste buds, stratified flattened cells, mucous cells, pigment cells, and stratified polygonal cells), middle layer (having stratified polygonal cells), and stratum germinativum (stratified columnar cells). In particular, the dermis has scales, well-developed vascularization, and a few blood capillaries just above the basement membrane, and a reduced diffusion distance was present in the lateral body. Consequently, adaptations such as thicker epidermis, well-developed vascularization, few blood capillaries, and a reduced diffusion distance may provide cutaneous respiration for survival in poorly oxygenated water during the periodic dry season.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9363545/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40597677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"In-situ formation of co particles encapsulated by graphene layers","authors":"Minjeong Lee, Gyutae Kim, Gyu Hyun Jeong, Aram Yoon, Zonghoon Lee, Gyeong Hee Ryu","doi":"10.1186/s42649-022-00076-z","DOIUrl":"10.1186/s42649-022-00076-z","url":null,"abstract":"<div><p>The process of encapsulating cobalt nanoparticles using a graphene layer is mainly direct pyrolysis. The encapsulation structure of hybrids prepared in this way improves the catalyst stability, which greatly reduces the leaching of non-metals and prevents metal nanoparticles from growing beyond a certain size. In this study, cobalt particles surrounded by graphene layers were formed by increasing the temperature in a transmission electron microscope, and they were analyzed using scanning transmission electron microscopy (STEM). Synthesized cobalt hydroxide nanosheets were used to obtain cobalt particles using an in-situ heating holder inside a TEM column. The cobalt nanoparticles are surrounded by layers of graphene, and the number of layers increases as the temperature increases. The interlayer spacing of the graphene layers was also investigated using atomic imaging. The success achieved in the encapsulation of metallic nanoparticles in graphene layers paves the way for the design of highly active and reusable heterogeneous catalysts for more challenging molecules.</p></div>","PeriodicalId":470,"journal":{"name":"Applied Microscopy","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9279520/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40588010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}