• The Korean Journal of Zoology
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• v.28 no.1
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• pp.1-8
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• 1985

A series of observation on sperm penetration in urodele (Ambystoma mexicanum) eggs are reported. The whole sperm including the tail appears to penetrate the egg surface. It can be demonstrated that the Ambystoma mexicanum egg is typically polyspermic. Each sperm penetration point is marked by a distinct crater on the egg surface the so called sperm pit. Initially, no sign of disruption in the surface structure observed. Once sperm penetration was complete, the site of entry became covered with long microvilli.

• The Korean Journal of Zoology
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• v.20 no.1
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• pp.49-56
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• 1977

Mexican axolotl(Ambystoma mexicanum)의 생활사, 기원, 실험실내에서의 유지 및 교배방법 등을 소개한다. 이 종은 난자형성과 발생의 연구면에서 몇가지 대단히 유리한 점을 가지고 있다. 즉 큰 염색체를 가진 대형의 난자를 보유하고 있는 점, 난자가 수란관을 통과하는 동안 총배설강내에서 수정하는 점, 초기 배아의 실험발생학, 세포학 및 생화학적 연구에 쉽사리 이용할 수 있다는 점과, 무엇보다도 난자형성과 배발생동안의 여러 가지 중요한 기능에 영향을 미치는 30여개 이상의 유전자를 이용하여 유전자조절현상을 밝혀낼 수 있다는 점이다.

• Korean Journal of Veterinary Research
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• v.61 no.3
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• pp.25.1-25.7
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• 2021

The axolotl has extraordinary regeneration capacity compared to other vertebrates. This remarkable potential has been attributed to its life-long neoteny, characterized by the exhibition of embryonic characteristics at the adult stage. A recent study provided a detailed morphological analysis of the sperm morphology of the Ambystoma mexicanum using routine and detailed histological techniques. The primary purpose of the present study is to describe a simple and inexpensive method for evaluating the morphology of axolotl sperm. In this study, spermatophore structures were collected and spread on slides and air-dried. The slides were stained with periodic acid Schiff, toluidine blue, Masson's trichrome, Giemsa, Spermac, and Diff-Quik dye for a morphological examination. The slides were coated with gold/palladium for a scanning electron microscopy examination. The sperm of the axolotl consisted of an elongated head, a neck, and a flagellum covered with an undulating membrane. The lengths of the midpiece, tail, and head were 8.575 ㎛, 356.544 ㎛, and 103.661 ㎛, respectively. In the flagellum part, the wavy membrane structure, whose function has not been explained, surrounds the tail. The data obtained from this study will constitute an important step in designing future research on the reproductive and regeneration capacity of the axolotl.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.57-58
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• 1998

From the present study, following conclusions can be drawn: 1. lide in other species, axolotl FGF-8 is proposed to play a similar role in the early phase of limb development. However, the mechanism of its expression might be somewhat different from amniotes considering its characteristic mesenchymal expression. 2. In the regenerating axolotl limbs, Fgf-8 expression profile suggests that it is involved in wound gealing, dedifferentiation, and blastema formation. 3. Exoggenously supplied FGF-8 can accelerate blastema formation and concomitantly increase the Msx-1 expression level at the early stage of limb regeneration. Furthermore, it can partially substitute for nerve factor(s) as has been indicated by the induction of blastema formation in the denervated regenerates after FGF-8 application. 4. The unique expression feature of Fgf-8 in hte mesenechymal tissue of the regenerating axolotl limb might be casually related to its remarkable regeneration capacity of urodele.

• The Korean Journal of Zoology
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• v.20 no.3
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• pp.149-157
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• 1977

At present over 3 dozen mutant genes have been recognized in the Mexican axolotl. These genes, all recessives, are categorized in 5 groups according to the nature of their effects and the developmental stage at which their phenotype is predominately expressed. They are genes affecting the oogenesis (maternal-effect genes), genes affecting the size of the nucleolus, genes affecting the development of specific tissues and organs, genes exert lethal effects on all cells or tissues (autonomous lethals), and genes affecting pigment cells. This report describes briefly the phenotypes and some of the current research applications of those genes.

• Development and Reproduction
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• v.2 no.1
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• pp.53-62
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• 1998

The lysosomal acid hydrolases including lysosomal acid phosphatase (LAP) are believed to play an important role in intracellular and extracellular degradation. LAP was reported to increase its activity in dedifferentiation stage during urodele limb regeneration. In the paresent study, LAP localization in the Mexican axolotl (Ambystoma mexicanum) limb regenerates was investigated by immunohistochemistry. LAP immunoreactivity with monoclonal antibody against Korean salamander (Hynobius leehii) LAP was observed mainly in the wound epidermis, blastema cells, muscle, and cartilage which were under dedifferentiation process in axolotl limb regenerates. Moreover, LAP immunoreactivity increased gradually during the early phase of lib regeneration and reached the peak level at dedifferentiation stage. However, as redifferentiation begans, LAP immunoreactivity decreased slowly to the basal level. Retinoic acid (RA) which is known to induce skeleton pattern duplication in regenerating urodele limb appears to enhance LAP immunoreactivity. In the RA-treate limg regenerates, LAP immunoreactivity was higher than in the normal regenerates. In addition, the LAP expression period was more extended in the RA treated regenerates than in the normal regenerates. These results suggest that RA is involved in the extension of dedifferentiation state in RA-treated limb regenerate.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.65-74
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• 1996

Treatment of regenerating amphibian limbs with retinoic acid (RA) is known to induce paftern duplication, which is closely related to the extent of dedifferentiation. In the present study, the activities of trypsin- and chymotrypsin-like proteases are examined to delineate a possible role in the process of dedifferentiation in the regenerating limbs of urodeles, the Korean salamander (Hynobius leechii) and the Mexican axolod (Ambystoma mexicanum). Specifically, we were interested to know if there is any correlation between trypsin- and chymotrypsin-like protease activities and the state of dedifferentiation which is augmented by RA treatment. We were also interested in expoloring if there is any species-specific difference in the profile of enzyme activities during limb regeneration. The results showed that the activities of these two enzymes reached a peak level at dedifferentiation stage, and RA treatment caused elevation of their activities, especially in the case of trypsin-like protease. The increase of trypsin-like protease activity after RA treatment was pronounced in the Korean salamander, which might reflect a species-specific responsiveness to RA. The present results imply that trypsin and chymotrypsin or similar proteases may play an active role in the process of dedifferentiation in regenerating limbs, and that trypsin or trypsin-like eryrymes might be involved in the RA-evoked enhancement of dedifferentiation which precedes overt pattern duplication.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.426-436
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• 1996

In previous studies, we have shown that lysosomal add phosphatase (LAP) activity increases at the dedifferentiation stage in the regenerating larval limbs of salamander, Hynobius leechii. Monoclonal antibodies against LAP were generated to determIne the spatial and temporal distribution of the protein In the regenerates.A total of 22 monoclonal antihodies recognizIng different epftopes of the protein were obtained, of which five strongly stained the regenerating limb by imunohistochemistry. in LAP immunohistochemical examination, LAP showed distribution coincident with the state of dedifferentiation, both spatially and temporally, in the limb regenerates. When unfractioned protein of regenerating salamander limbs were separated by gel electrophoresis and immunoblotted, the antibodies recognized a single protein band of 53 kl)a, which comigrates with a monomerlc subunit of IAR Using the anti-IAP antibodIes as probe, we investigated the cross-reactivities of LAPs from other sources. The immunoreadive bands on Western blots appeared to be the same In molecular mass-53 kl)a in axoloti and Xenopus, but no protein band was detected in mouse, Drosophila, or C. elegans.These results show that the antibodies generated in this study spedfically recognize Hynoblus leeclili IAp and that IAPs may be highiy conserved among amphibians. Furthermore, the distdbution of the protein is consistent with a role for LAP in the dedifferentiation process of limb regeneration.