• The Korean Journal of Malacology
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• v.22 no.1 s.35
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• pp.39-49
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• 2006

Ultrastructure of germ cell differentiation during supermatogenesis and the reproductive cycle in male Patinopecten yessoensis was studied by histological and cytological observations. The gonadosomatic index (GSI) in males rapidly increased and reached a maximum in April when seawater temperature gradually increased. Then the GSI gradually decreased from May through July when spawning occurred. Accordingly, monthly changes in the GSI in males coincided with testicular maturation and spawning periods. The sperm morphology of P. yessoensis belongs to the primitive type and showed general characteristics of external fertilization species. The head of the spermatozoon is approximately $3.50{\mu}m$ in length: the sperm nucleus and acrosome are approximately $2.90{\mu}m\;and\;0.60{\mu}m$ in length, respectively. The nuclear type of the spermatozoon is vase in shape, and the acrosome is cone type. The axoneme of the tail flagellum consists of nine pairs of microtubules at the periphery and a pair of central microtubules in the center The satellite body (which is formed by the centriole) and four mitochondria appear in the middle piece of the spermatozoon. The spawning period was from April through July and the main spawning occurred from May to June when seawater temperatures gradually increased. The reproductive cycle of this species can be classified into five successive stages; early active stage (September to November), late active stage (October to March), ripe stage (February to August), spawning stage (April to July), and spent/inactive stage (July to November).

• Animal Systematics, Evolution and Diversity
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• v.8 no.2
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• pp.231-242
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• 1992

Samples of two species of genus Ratts(black rat, Rattus rasttus Linnaeus; common rat, Rattus norvegicus Berkenhaut) in Korea were trapped and their 31 morphometric charcters were analyzed statistically in order to determine the range of geographic variation within each species and the interspecific differences. In addition, chromosomal G-bands and C-bands were compared and the fragment patterns of mtDNA resulted from the digestion with restriction enzymes were also analyzed. Samples of black rats from six localities in Korea were similar with one another in their morphometric characters: in head and body length, length of tail vertebrae, conventional karyotype and C-bands, they are comparable to Rattus rattus tanezumi in Japan. Specimens of common rats from seven localities in Korea were similar with one another in their morphometric characters: in conventional karyotype, they are comparable to Rattus norvegicus caraco in eastern Asia. Common rats differ from black rats in their morphometric characteris, chromosomal karyotypes and mtDNA. It is confirmed that correct species name of black rat in Korea is Rattus rattus tanezumi Tempminck: species name of common rat in Korea is Rattus norvegicus caraco Pallas: the common rat is a species, which is distinct from the black rat.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.2
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• pp.67-75
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• 2019

Objective: Sperm cryopreservation has been widely used in assisted reproductive technology, as it offers great potential for the treatment of some types of male infertility. However, cryopreservation may result in changes in membrane lipid composition and acrosome status, as well as reductions in sperm motility and viability. This study aimed to evaluate sperm DNA fragmentation damage caused by conventional freezing using the sperm chromatin dispersion test. Methods: In total, 120 fresh human semen samples were frozen by conventional methods, using SpermFreeze Solution as a cryoprotectant. Routine semen analysis and a Halosperm test (using the Halosperm kit) were performed on each sample before freezing and after thawing. Semen parameters and sperm DNA fragmentation were compared between these groups. Results: There was a significant decrease in sperm progressive motility, viability, and normal morphology after conventional freezing (32.78%, 79.58%, and 3.87% vs. 16%, 55.99%, and 2.55%, respectively). The sperm head, midpiece, and tail defect rate increased slightly after freezing. Furthermore, the DNA fragmentation index (DFI) was significantly higher after thawing than before freezing (19.21% prior to freezing vs. 22.23% after thawing). Significant increases in the DFI after cryopreservation were observed in samples with both normal and abnormal motility and morphology, as well as in those with normal viability. Conclusion: Conventional freezing seems to damage some sperm parameters, in particular causing a reduction in sperm DNA integrity.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.696-703
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• 2019

Cronobacter sakazakii is an opportunistic pathogen causing serious infections in neonates. In this study, a bacteriophage ${\Phi}CS01$, which infects C. sakazakii, was isolated from swine feces and its morphology, growth parameters, and genomic analysis were investigated. Transmission electron microscopy revealed that ${\Phi}CS01$ has a spherical head and is 65.74 nm in diameter with a 98.75 nm contracted tail, suggesting that it belongs to the family Myoviridae. The major viral proteins are approximately 71 kDa and 64 kDa in size. The latent period of ${\Phi}CS01$ was shown to be 60 min, and the burst size was 90.7 pfu (plaque-forming units)/infected cell. Bacteriophage ${\Phi}CS01$ was stable at $4-60^{\circ}C$ for 1 h and lost infectivity after 1 h of heating at $70^{\circ}C$. Infectivity remained unaffected at pH 4-9 for 2 h, while the bacteriophage was inactivated at pH <3 or >10. The double-stranded ${\Phi}CS01$ DNA genome consists of 48,195 base pairs, with 75 predicted open reading frames. Phylogenetic analysis is closely related to that of the previously reported C. sakazakii phage ESP2949-1. The newly isolated ${\Phi}CS01$ shows infectivity in the host bacterium C. sakazakii, indicating that it may be a promising alternative to antibacterial agents for the removal of C. sakazakii from powdered infant formulas.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.720-726
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• 2022

The behavior changes of the lipid bilayer, induced by the hydroxybutyric-acid incorporation, were investigated with respect to each phase of the layer using fluorescence intensity change. Spherical phospholipid bilayers, called vesicles, were prepared using an emulsion technique. Only in the aqueous inside of the vesicles was encapsulated 8-Aminonaphthalene-1,3,6-trisulfonic-acid-disodium-salt(ANTS). p-Xylene-bis-N-pyridinium-bromide(DPX) was included as a quencher only outside of the vesicles. The fluorescence scale was calibrated with the ANTS-encapsulated vesicles in DPX-dispersed-buffer taken as 100% and the mixture of ANTS and DPX in the buffer as 0%. Hydroxybutyric-acid addition into the vesicle solution led the change in the bilayer. The change was found to be related to the phase of each layer according to the ratio of hydroxybutyric-acid to lipid. These results seem to depend on the stability of the vesicles, due to the osmotic and volumetric effects on the arrangement in both head-group and tail-group.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.194-200
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• 2021

Schwannomas originate from Schwann cells, and they are the most common benign neoplasms of the peripheral nerves. They can occur in most parts of the body but have a predilection for the head, the neck, and the flexor aspects of the extremities. Pancreatic schwannomas are uncommon, and only a few cases have been reported in the English literature. Approximately two-thirds of pancreatic schwannomas undergo cystic degeneration, and they should be considered in the differential diagnosis of solid pancreatic tumors with cystic changes to facilitate accurate diagnosis and optimal treatment. We report a case of a pathologically proven schwannoma in the pancreatic tail with multiple cystic and hemorrhagic changes followed by a review of relevant literature.

• Development and Reproduction
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• v.11 no.1
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• pp.31-41
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• 2007

The spermiogenesis of Crocidura shantungensis were studied by electron microscope. All process of spermiogenesis was divided into 11 phases 15 steps, based on the morphological features of the nucleus and cell organelles in cytoplasm of spermatids. The spermatids in Golgi and cap phases were a spherical shape. On the other hand, at the early acrosomal phase they changed into an oval shape, and the tail was created in this phase. In maturation phase, the shapes of spermatid head were thin and longish. Until step 7 the direction of spermatids head turned toward the lumen of the seminiferous tubule. From step 8 to step 15 their heads turned toward the basal lamina. In step 12, the nucleus and acrosome shown maximal elongation. From Step 13 the nucleus of spermatids became flat, simultaneously with flat expansion of the acrosome expanded, and the visible whole lengths of spermatids were tend to be shorten. Spermatid heading which arrived to step 14 was taken the final shape. The nucleus was doing the wedge shape, and the nuclear chromatins condensed completely and homogenized. In the spermiation phase, the spermatids were gradually disconnected from the cytoplasm of the Sertoli cell. In this phase, the acrosome of the spermatids were fully shorten and flat, and the spermatozoa completed the process of heading and the tailing. Considering all the results, the spermiogenesis may be useful information to analyze the differentiation of spermatogenic cells.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.5
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• pp.219-224
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• 2015

In this paper, the designed fish robots DOMI ver1.0 is researched and development for aquarium underwater robot. The presented fish robot consists of the head, 1'st stage body, 2nd stage body and tail, which is connected two point driving joints. The model of the robot fish is analysis to maximize the momentum of the robot fish and the body of the robot is designed through the analysis of the biological fish swimming. Also, Lighthill was applied to the kinematics analysis of robot fish swimming algorithms, we are applied to the approximate method of the streamer model that utilizes techniques mimic the biological fish. The swimming robot has two operating mode such as manual and autonomous operation modes. In manual mode the fish robot is operated to using the RF transceiver, and in autonomous mode the robot is controlled by microprocessor board that is consist PSD sensor for the object recognition and avoidance. In order to the submerged and emerged, the robot has the bladder device in a head portion. The robot gravity center weight is transferred to a one-axis sliding and it is possible to the submerged and emerged of DOMI robot by the breath unit. It was verified by the performance test of this design robot DOMI ver1.0. It was confirmed that excellent performance, such as driving force, durability and water resistance through the underwater field test.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.331-340
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• 1998

We determined the incidence of activation, male pronuclear formation and apposition of pronuclei in porcine oocytes following intracy-toplasmic injection of various porcine sperm components and foreign species spermatozoa, such as mouse, human or cattle. The porcine oocytes were activated by injection of a spermatozoon or an isolated sperm head. Neither isolated sperm tail nor perinuclear material removed sperm head activated oocytes. Because injection of mouse, bovine or human spermatozoon activated porcine oocytes, the sperm born activation factors is not strict species specific. Male pronuclear formation and pronuclear apposition were observed in the porcine oocytes following injection of porcine, bovine, mouse or human spermatozoa. The electrical stimulation following sperm cell injection did not enhance the incidence of male pronuclear formation nor pronuclear apposition comparent with sperm cell injection alone (p>0.1). Mitosis and two cell division in some oocytes were observed at 20 to 24 h after injection of porcine spermatozoon. However, none of oocytes following injection of mouse, bovine or human spermatozoa developed to the mitotic metaphase or normally divided to the two cell stage. These results suggested that the oocyte activating factor(s) presented in the perinuclear material and it is not species specific for the porcine oocyte.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.339-346
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• 1994

An understanding of the structure and function of mammalian spermatozoa requires the iso-lation of these components. In this study, frozen-thawed bovine spermatozoa were treated by physical treatments (vortexing, 26 gauge needle, strained 26 gauge needles and freezing-thawing) or chemical treatments (trypsin, dithiothreitol, sodium dodecylsulfate and $\beta$-mercaptoethanoJ) to yield free heads and tails. The most effective treatment was repeated pumping of sperm suspension through a strained 26 gauge needle conneted to a syringe. Spermatozoa by this treatment were mainly broken at the junction of the head and the tail, resulting in 90-100% yields. Also, sperm head surface did not modify during strained 26 gauge needle treatment when either spermatozoa or sperm heads were incubated in 250${\mu}\textrm{g}$/ml of FITC-UEA 1 for 1 h at room temperature to detect the modification of sperm surface components. Other physical treatments were less efficient for the breakdown of spermatozoa. The effects of chemical treatments on bovine spermatozoa are not noticeable. Dissected sperm heads and tails should be fractional leading to nearly pure components by sucrose gradient centrifugation at 1,000 rpm for 15 min. The result suggest that the established method may be useful for the biochemical study of spermatozoal components, and the understanding of oocyte activation mechanism either by spermatozoal components during fertilization or microinjection of isolated components.