• Animal cells and systems
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• 제3권1호
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• pp.1-7
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• 1999

Gonadotropin-releasing hormone (GnRH) was originally isolated as a hypothalamic peptide that regulates reproduction by stimulating the release of gonadotropins. Using comparative animal models has led to the discovery that GnRH has a more ancient evolutionary origin. Durinq evolution GnRH peptide underwent gene duplication and structural changes to give rise to multiple molecular forms of GnRHs. Mammalian GnRH initially considered to be the sole molecular form, is now grouped as a family of peptides along with GnRH variants determined from representatives in all classes of vertebrates. Vertebrate species including primates and humanshave more than one GnRH variant in individual brains; a unique GnRH form in the forebrain and chicken IIGnRH in the midbrain. Furthermore, several species of bony fish have three molecular variants of GnRH: salmon GnRH sea-bream GnRH and chicken II GnRH. Also, it has been shown that in addition to the olfactory placodes and the midbrain, there is a third embryonic source of GnRH neurons from the basal diencephalon in birds and fish, which might be true for other vertebrates. Therefore, comparative animal models like fish with discrete sites of expression of three molecular variants of GnRH in individual brains, could provide insight into novel functions of GnRH variants, conservation of gene regulation, and mechanisms governing reproduction in vertebrates.

• Applied Microscopy
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• 제44권4호
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• pp.111-116
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• 2014

This study investigates the developmental pattern of adhesive discs (ADs) to highlight the ontogeny and structural changes that occur during the growth of Boston ivy. Initiation to postmortem features of ADs were examined through light and scanning electron microscopy. The study also reveals a new finding of the dislocation of peripheral tissues of adaxial origin. Four phases of attachment are suggested with regards to its climbing behavior: 1) pre-attachment, 2) upon attachment, 3) after attachment, and 4) final attachment. During initiation, several ADs originate from tendril primordia without epidermal differentiation. However, different growth rates in the epidermis results in completely different ADs. ADs were discerned by size, shape, and color during expansion, but cells in the adaxial surface remained alive longer than the other side. Upon contact, the ADs demonstrate simultaneous growth and deterioration, but once attachment is established the latter process subdues to final stages. Epidermal transformation, adhesive secretion, cellular disruption, and mechanical stress were essential for the self-clinging nature of Boston ivy. The post-attachment sequence is also believed to be critical in achieving maximum mechanical strength to provide extensive support. The developmental process of ADs is prompted by tactile stimulation but in a highly organized and systematic manner.

• Molecules and Cells
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• 제43권2호
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• pp.126-138
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• 2020

The transcription factor RUNX1 first came to prominence due to its involvement in the t(8;21) translocation in acute myeloid leukemia (AML). Since this discovery, RUNX1 has been shown to play important roles not only in leukemia but also in the ontogeny of the normal hematopoietic system. Although it is currently still challenging to fully assess the different parameters regulating RUNX1 dosage, it has become clear that the dose of RUNX1 can greatly affect both leukemia and normal hematopoietic development. It is also becoming evident that varying levels of RUNX1 expression can be used as markers of tumor progression not only in the hematopoietic system, but also in non-hematopoietic cancers. Here, we provide an overview of the current knowledge of the effects of RUNX1 dosage in normal development of both hematopoietic and epithelial tissues and their associated cancers.

• 환경생물
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• 제39권3호
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• pp.383-389
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• 2021

The Erythropeltidales are a common group of small, mostly epiphytic, marine red algae. However, they are little known in Korea. Many of the described species of Erythropeltidales differ subtly in morphology, and often the morphological differences are due to the substrate or environmental changes. Integration of molecular data with standardized culture conditions has been recommended to account for these algae. A Madagascaria species was first collected from the western coast of Korea and was identified as Madagascaria erythrocladioides based on the morphological and molecular characteristics. Morphological characteristics conformed well with its original description, and the phylogenetic analysis based on rbcL sequence showed Korean M. erythrocladioides nests in the same clade with the original species described in Japan with a genetic distance of 0.0-0.1%. This species was isolated from a red alga, Pterocladiella capillacea, in laboratory culture. The thallus ontogeny and host preference were examined by a co-culture with 13 different species of algae. Results showed a relatively broad host preference in mono-spore attachment and epiphyte development of Madagascaria erythrocladioides. Mono-spores of M. erythrocladioides attached to most of the red algal hosts' surfaces but no crustose thalli developed on some of the algal hosts even after one month of co-culture.

• Molecules and Cells
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• 제44권5호
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• pp.292-300
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• 2021

Macrophages residing in various tissue types are unique in terms of their anatomical locations, ontogenies, developmental pathways, gene expression patterns, and immunological functions. Alveolar macrophages (AMs) reside in the alveolar lumen of the lungs and serve as the first line of defense for the respiratory tract. The immunological functions of AMs are implicated in the pathogenesis of various pulmonary diseases such as allergic asthma, chronic obstructive pulmonary disorder (COPD), pulmonary alveolar proteinosis (PAP), viral infection, and bacterial infection. Thus, the molecular mechanisms driving the development and function of AMs have been extensively investigated. In this review article, we discuss the roles of granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor (TGF)-β in AM development, and provide an overview of the anti-inflammatory and pro-inflammatory functions of AMs in various contexts. Notably, we examine the relationships between the metabolic status of AMs and their development processes and functions. We hope that this review will provide new information and insight into AM development and function.

• Animal cells and systems
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• 제1권3호
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• pp.497-505
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• 1997

Dopamine plays diverse roles in the fetal brain development and differentiation. However, the development of the dopaminergic neurons and its receptors has not been fully understood. In our studies, in situ hybridization and immunohistochemical methods were used to investigate the ontogeny of dopaminergic neurons and its receptor subtypes during the fetal development of the rat. In situ hybridization data showed that dopamine $D_1$ and $D_2$ receptor mRNAs were expressed in the ventricular and subventricular zones of ganglionic eminence, thalamus, hypothalamus, and cortical neuroepithelium on gestational day 13. Expression of dopamine $D_1$ and $D_2$ receptors during gestational days 17 and 19 reached the same or similar level of that in the adult brain. Expression of $D_1$ receptor mRNA preceded that of $D_2$ receptor mRNA in the early developmental stage, although this pattern was reversed with the sharp increase of $D_2$ receptor mRNA soon after. $D_2$ receptor mRNA was expressed in substantia nigra of mesencephalon of the fetal rat brain. However, $D_1$ receptor mRNA was not detected in substantia nigra. Our results indicate that dopamine might function in the fetal brain during the early gestational period.

• Asian-Australasian Journal of Animal Sciences
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• 제22권12호
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• pp.1633-1639
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• 2009

This study investigated the effect of maternal undernutrition during late pregnancy on the growth and development of ovine fetal visceral organs. One hundred Mongolian ewes were mated at a synchronized oestrus and divided into three groups and offered 0.175 MJ ME $kgw^{-0.75}\;d^{-1}$ (Restricted Group1; RG1), 0.33 MJ ME $kgw^{-0.75}\;d^{-1}$ (Restricted Group2; RG2) and ad libitum access to feed (Control Group; CG) during late pregnancy (90 days). Selected animals in each group were slaughtered immediately at d 90 of pregnancy and after parturition (neonatal lambs), and major visceral organs were removed and weighed separately. The results indicated that the weights of lung (p<0.01), spleen (p<0.01), heart (p<0.05), liver (p<0.05) and abomasum (p<0.01) in RG1 were significantly lighter than those of CG. For RG2, only the weights of the lung (p<0.05) and spleen (p<0.01) were significantly lighter than those of CG; when expressed as a percentage of body weight, significance was retained in the spleen (p<0.01) for both restricted groups, but the percentage of brain in RG1 was significantly higher than that in CG (p<0.01). For lung and spleen, the amount of DNA was significantly lower (p<0.01) in both groups of restricted neonatal lambs compared to CG; however, there was a significant difference only between RG1 and CG for protein: DNA ratio (p<0.01). The DNA content of kidney, abomasum and jejunum were decreased (p<0.05) in RG1 neonatal lambs, but protein: DNA ratio in the liver was decreased compared with that of CG (p<0.05). The plane of maternal undernutrition during late pregnancy had a significant effect on the growth and development of fetal visceral organs, which altered ontogeny of fetal organ growth and development. These perturbations in fetal visceral development may have significant implications on postnatal growth and adult health.

• Asian-Australasian Journal of Animal Sciences
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• 제7권1호
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• pp.75-81
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• 1994

To elucidate the relationship between steroidogenesis and sex differentiation in the duck, plasma, testicular and ovarian testosterone, estradiol-$17{\beta}$ and progesterone concentration in male and female embryo of day 11 to 27 (just before hatching) of incubation and in 1- to 7-day-old male and female duckling were investigated by radioimmunoassays. Plasma estradiol-$17{\beta}$ concentration in female embryos declined from very high at days 11 and 15 of incubation and remained at low levels after hatching. Male plasma estradiol-$17{\beta}$ concentration were always lower than those of the female throughout this period. Plasma testosterone and progesterone concentrations in both sexes were low during the embryonic stage, but then increased to peaks 3 days and 1 day after hatching, respectively. Estradiol-$17{\beta}$ contents were much higher in the left ovary than the right ovary or testes throughout the experimental period. The estradiol-$17{\beta}$ content of the left ovary was very high at day 15 of incubation, and decreased gradually thereafter. Both in right ovary and testes, estradiol-$17{\beta}$ contents were always low. Testosterone and progesterone contents in the left ovary were low from day 11 to 23 of incubation, and reached a peak 1 day after hatching. Progesterone content in the right ovary and testes were low levels over time period examined. Testosterone and progesterone contents were much higher in the left ovary than the right ovary and testes. The present results clearly demonstrate that the capacity of the embryonic left ovary of duck to synthesize estradiol-$17{\beta}$ and testosterone is much higher than that of the embryonic testis. It is suggested that estrogen secreted from the embryonic ovary earlier than day 15 of incubation has an important role in female sexual differentiation in the duck, and the sex of the avian species is basically male with homozygous sex chromosome (ZZ).

• IMMUNE NETWORK
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• 제1권1호
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• pp.53-60
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• 2001

Background: The human mic2 gene is a pseudoautosomal gene that encodes a cell surface antigen, CD99. High levels of CD99 constitute a tumor marker in Ewing s sarcoma (ES). We have recently demonstrated that CD99-induced apoptosis occurs only in undifferentiated ES cells, not in differentiated ES cells, raising the possibility of the involvement of CD99 in neural ontogeny. Methods: To elucidate the relations between the expression of CD99 and the differentiation of neural cells and the mechanism by which the expression of CD99 is regulated, we analyzed the differential patterns of CD99 expression in SH-SY5Y by treatment of 12-O-tetradecanoyl-13-phorbol acetate (TPA) and retinoic acid. In addition, to explore the transcriptional activity of CD 99 during neural cell differentiation, SH-SY5Y cells were transiently transfected with a CD99 promoter-driven luciferase construct, and treated with the inducers. Results: In immunoblotting and flow cytometry, the expression level of CD99 was increased on differentiated SH-SY5Y cells induced by TPA and retinoic acid. The luciferase activity was elevated by the treatment with TPA, known to mature SH-SY5Y cells toward a sympathetic neuronal lineage, whereas retinoic acid inducing a sympathetic chromaffin lineage displayed little effect. Conclusion: The result indicates that CD99 might be expressed only on cells maturing toward a neuronal lineage among differentiating primitive neuronal cells. In addition, the expression of CD99 seems to be regulated at the transcriptional level during the differentiation.

• 전자공학회논문지S
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• 제35S권11호
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• pp.88-95
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• 1998

본 논문은 인공생명 기법을 이용하여 생물의 정보처리 시스템을 구현하고자 하는 것이다. 자연계의 생물은 그 자체로 훌륭한 정보처리 시스템이다. 생물체는 하나의 생식 세포로부터 발생된다. 또한 이 개체의 종은 진화의 과정을 통해 환경에 적응한다. 본 논문에서는 이와 같은 생물학적인 발생과 진화의 개념을 이용하여 신경망을 설계하는 방법을 제안한다. 생물체의 개체발생은 발생모델의 하나인 셀룰라 오토마다(CA)를 통하여 구현하였고 진화과정은 진화 알고리즘(EAs)을 사용하였다. 우리는 이와 같이 구현한 '진화하는 셀룰라 오토마타 신경망'을 줄여서 ECANS1이라 명명하였다. 셀 사이의 연결은 CA 법칙에 의하여 결정되며, 셀의 초기 패턴이 진화함으로써 유용한 신경망을 찾아낸다. 신경망의 각 셀 즉 뉴런은 생물의 발화 ${\cdot}$ 비발화의 특성을 갖는 카오스 뉴런 모델을 사용하였다. 그리고 신경마의 최종 출력값은 뉴런의 발화 빈도로서 나타내었다. 제안한 방법은 Exclusive-OR 문제 및 패리티 문제에 적용함으로써 그 유효성을 검증하였다.