• Journal of Photoscience
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• v.9 no.2
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• pp.261-263
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• 2002

The presence of retinals (retinal and 3,4-didehydroretinal) has been known in the eggs of wide range of oviparous vertebrates, but the biological significance of the egg retinals has yet to be clarified. We here show that retinals are the major components of retinoids in the eggs of all species of chordate animals we examined. The egg retinals were commonly bound to egg yolk proteins, the storage proteins, via a Schiff base linkage. The Schiff base linkage, which protects the reactive aldehyde group, would negate the toxicity of aldehyde, and enable to accumulate much amount of retinals. The retinals in chordate eggs are considered to be the precursor of functional retinoids, such as photoreceptive pigment chromophores and retinoic acid, during development. The results of the present research strongly suggest that retinals in the eggs of oviparous chordates are the common and essential mode of retinoid storage.

• Journal of Photoscience
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• v.9 no.2
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• pp.44-46
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• 2002

In the vertebrate retina, rods mediate twilight vision and cones daylight vision. Rods have been purified easily from the retina, and thus the phototransduction mechanism in rods is now well documented. However, it has not been possible to purify cones in large quantities, and therefore, the knowledge on the mechanism in cones is limited. Here we report purification of carp (Cyprinus carpio) cones with a stepwise Percoll gradient. Using purified cells, we compared the phototransduction mechanism between rods and cones. The results showed that both transducin activation and phosphodiesterase activation are less effective, and visual pigment phosphorylation is faster in cones. These differences explain lower light-sensitivity and briefer photoresponse time course in cones.

• Journal of Life Science
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• v.10 no.1
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• pp.20-23
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• 2000

Mono-ADP-ribosylation, catalyzed by ADP-ribosyltransferases, is a post-translational modification of proteins in which the ADP-ribose moiety of NAD is transferred to an acceptor protein. Previously, we have identified and cloned a glycosylphosphatidylinositol-linked ADP-ribosyltransferase (Yac-1) from mouse lymphoma cells. Yac-1 enzyme contains three regions (region I,II,III) similar to those found in several bacterial toxins and vertebrate ADP-ribosyltransferases. Site-directed mutagenesis was performed to verify the role of Glu 233 in region III. Mutants E233Q, E233D and E233A were inactive for ADP-ribosyltransferase activity. Thus Glu 233 in Yac-1 is essential for enzyme activity, suggesting that Glu 233 in Glu-rich motif near the carboxy terminus plays a catalytic role in ADP-ribosyltransferase activity.

• Bulletin of the Korean Chemical Society
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• v.31 no.3
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• pp.588-594
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• 2010

Two types of resin-conjugated Tamiflu analogs were synthesized by modifying our original synthetic route of oseltamivir phosphate (Tamiflu). The prepared resins bound to influenza virus neuraminidase, the main target of Tamiflu. The resins will be useful for isolating and identifying presumed endogenous vertebrate proteins that interact with Tamiflu, which might relate to the rarely observed abnormal behavior exhibited by some influenza patients treated with Tamiflu.

• BMB Reports
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• v.48 no.4
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• pp.223-228
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• 2015

The Drosophila lymph gland is the hematopoietic organ in which stem-like progenitors proliferate and give rise to myeloid-type blood cells. Mechanisms involved in Drosophila hematopoiesis are well established and known to be conserved in the vertebrate system. Recent studies in Drosophila lymph gland have provided novel insights into how external and internal stresses integrate into blood progenitor maintenance mechanisms and the control of blood cell fate decision. In this review, I will introduce a developmental overview of the Drosophila hematopoietic system, and recent understandings of how the system uses developmental signals not only for hematopoiesis but also as sensors for stress and environmental changes to elicit necessary blood responses. [BMB Reports 2015; 48(4): 223-228]

• Molecules and Cells
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• v.41 no.4
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• pp.257-263
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• 2018

Vertebrate organ development is accompanied by demarcation of tissue compartments, which grow coordinately with their neighbors. Hence, perturbing the coordinative growth of neighboring tissue compartments frequently results in organ malformation. The growth of tissue compartments is regulated by multiple intercellular and intracellular signaling pathways, including the Hippo signaling pathway that limits the growth of various organs. In the optic neuroepithelial continuum, which is partitioned into the retina, retinal pigment epithelium (RPE) and ciliary margin (CM) during eye development, the Hippo signaling activity operates differentially, as it does in many tissues. In this review, we summarize recent studies that have explored the relationship between the Hippo signaling pathway and growth of optic neuroepithelial compartments. We will focus particularly on the roles of a tumor suppressor, neurofibromin 2 (NF2), whose expression is not only dependent on compartment-specific transcription factors, but is also subject to regulation by a Hippo-Yap feedback signaling circuit.

• Biomedical Science Letters
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• v.18 no.2
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• pp.96-103
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• 2012

Kv 4.2 ion channel protein has an ability to open at subthreshold membrane potentials and to recover quickly from inactivation. That is very important for neuronal signal transmission in vertebrate brain. In order to purify Kv 4.2 protein, the novel purification methods were experimented. The purification procedure utilized chromatography on DE-52 ion exchange column and affinity chromatography on a WGA-Sepharose 4B, and Kv 4.2 affinity column chromatography. It was found that 0.5% (wt./vol.) Triton X-100 detergent in lysis buffer worked well for Kv 4.2 protein solubilization from rat brain membrane. Protein quantitative determination was conducted by BCA method at 562 nm for each purification step to avoid determination interference of protein at 280 nm by detergent. The confirmation of Kv 4.2 existence and amount is performed using by SDS-PAGE/immunoblotting or 96-well dot blotting. The Kv 4.2 without interacting protein that contains carbohydrate, was purified from novel biochemical 3-steps purification method for further research.

• The Journal of the Korean dental association
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• v.41 no.2 s.405
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• pp.116-123
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• 2003

Antimicrobial Peptides are natural antibiotics evolved by many plants, invertebrate, and vertebrate to defend against the microbial infection. Antimicrobial peptides show a broad-spectrum antimicrobial activity with little opportunity for the development of resistance since they target microbial membranes that distinguish microbes from enkaryotic cells. The oral cavity is constantly exposed to microbial challenges and antimicrobial peptides play an important role in managing the oral health. With the increase of resistant micro-organisms to conventional antibiotics, antimicrobial peptides are attracting interests as novel antibiotics. In this review, the characteristics of antimicrobial of antimicrobial peptides including the classification, mechanism of action, resistance, and expression in the oral cavity have been discussed in the prospects of application to oral disease.

• The Korean Journal of Zoology
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• v.22 no.3
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• pp.115-124
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• 1979

Two homotetrameric lactate dehydrogenase isozymes from Fluta alba and one from Ophicephalus argus were purified by combination of gel filtration and DEAE-cellulose chromatogrphy. The final preparations were isozymically pure and used to elicit antibodies in rabbits. The immunochemical reactivities demonstrated that the amino acids of active site is not to be included in the antigenic determinants, that antibodies or unknown component of immunized rabbit serum might be responsible for the electrophoretic abnormality and that two subunits share common antigenic determinants, reflecting that these polypeptides have a common evolutionary origin.

• Korean Journal of Poultry Science
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• v.26 no.2
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• pp.109-118
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• 1999

Hen's eggs have been regarded as one of the best animal bioreactors to produce biologically active peptides originated from many organisms including human. Despite the last decade's efforts to produce transgenic chicken for any commercial purposes, the results so far reported are very disappointing, indicating that hen's eggs are very difficult to crack for transgenesis. Comparatively large female gamete with enormous amount of yolk may be one of the major obstacles in achieving a similar feat to those of other vertebrate species including mouse, sheep, fish and frog. The delay or less efficiency evidenced may instruct to try an alternative way of gens transfer into chicken egg. Sperm-mediated gene transfer is one of them, and may require a great deal of understanding of mechanisms involved in early fertilization and embryonic development. In other animals where the technique was successful, basic mechanisms have been well studied and established only by painstaking efforts for decades. This paper discusses the accumulated knowledge on early fertilization mechanism in the chicken and how can this information be utilitzed to find the alternative gene transfer in making transgenic chicken.