• 한국발생생물학회지:발생과생식
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• 제2권2호
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• pp.141-148
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• 1998

돌고기 Pungtungia herzi 정자의 미세구조를 주사 및 투과 전자현미경적 방법으로 연구하였다. 정자는 구형의 두부, 짧은 중편 및 꼬리로 구성되어 있으며 비교적 그 구조가 단순하고 그 길이는 약 37.4$mu extrm{m}$이었다. 정자의 미세구조에서 핵에 대한 접선 방향으로의 편모 배열, 짧은 핵 그리고 미토콘드리아의 비대칭적 배열은 잉어과 정자의 공통된 특징과 마찬가지로 나타났으며, 대부분의 경골어류에서와 같이 첨체를 가지고 있지 않았다. 반면 돌고기 정자에서는 핵막의 구조와 미토콘드리아에서 현저한 특징을 나타내었다. 핵막은 매우 심하게 파동되어 있으며 얕은 핵와내의 기부 및 말단중심립은 약 130$^{\circ}$의 각도로 배열되어 있었다. 미토콘드리아는 제 1 정모세포기에 5개 이상 관찰되었으나 성숙한 정자에서는 하나의 형태로 융합되어 있었다. 이러한 양상은 융합되지 않은 다른 잉어류 정자에서의 미토콘드리아와 비교할 때 현저한 차이가 있었다. 정자의 계통 진화적 견지에서, 돌고기에서와 같이 융합된 미토콘드리아는 융합되지 않고 분리되어 있는 미토콘드리아에 비해 원거리 형질(apomorphic character)로 간주된다. 한 개의 미토콘드리아를 가지는 정자는 현재까지 Rhodeus 이외의 다른 잉어류 정자에서는 보고된 바 없었다.

• 한국응용곤충학회지
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• 제40권1호
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• pp.15-21
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• 2001

여섯줄 위축선충속에 1신종 Geocenamus seonunensisn. sp.과 1미기록종 Geocenamus processus (Siddiqi, 1979) Brzeski, 1991를 새로히 채집하였다; Geocenamus seonunensis n. sp.는 G. myungsugae Choi & Geraert, 1993와 비슷하나 구순부가 단추모양이 아니고, 구침 길이가 56~67$\mu$m 으로 훨씬 긴 점이 다르다. G. tumensis(Skwiercz, 1984)Brzeski, 1991와는 둥근 수정낭을 가지고, 구침이 훨씬 긴 것이 다르고, G. superbus(Allen, 1955) Fortuner & Luc, 1990와는 꼬리 끝이 주름 진 것이 다르고, G. brevicaudatus(Peng & Hunt, 1995) Brzeski, 1998와는 구침이 긴 것이 다르고, G. longes (Wu, 1969) Tarjan, 1973. 와는 표피의 종주선의 수가 적은 것이 다르다.

• Applied Microscopy
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• 제32권4호
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• pp.303-310
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• 2002

우리나라 동해안에 가장 많이 서식하는 조개류인 대복의 정소구조와 정자형성과정을 광학현미경과 투과전자현미경으로 조사한 결과는 다음과 같다. 대복의 정소는 소성결합조직으로 구성된 다수의 정자형성 소낭을 가진다. 동일한 정자형성 소낭 내에서는 여러 단계의 생식세포들이 관찰되었다. 정원세포들은 정자형성 소낭벽에 부착되어 있으며, 커다란 핵과 뚜렷한 인을 가진다. 정모세포에서는 연접사복합체와 골기체의 발달을 확인할 수 있었다. 정세포의 핵은 전자밀도가 높은 과립상의 염색질로 구성되며, 정자변태과정 동안에 핵의 응축 및 첨체와 편모의 형성을 관찰할 수 있었다. 정소 내에서 완숙 정자들은 다발을 형성하고 있으며, 두부, 중편, 미부로 구성되어 있었다. 두부의 길이는 약 $8.5{\mu}m$로, 첨체부와 핵 부위로 구분된다. 첨체는 길이 약 $1.1{\mu}m$의 총알형태였다. 두부와 첨체 사이에서는 미세섬유로 구성된 첨체기둥이 확인되었다. 중편에는 4개의 미토콘드리아를 가지며, 꼬리의 횡단면은 "9+2"의 구조를 나타냈다.

• Applied Microscopy
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• 제33권3호
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• pp.243-250
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• 2003

넙치의 웅성생식세포의 발달과 정자 구조를 광학현미경과 투과전자현미경을 이용하여 관찰하였다. 곡정세관의 각 소낭내의 생식상피에서는 분열 증식중인 정원세포군이 염기성 염료에 미약하게 반응하기 시작한다. 정소조직의 계속적인 발달로 각 소낭내에는 분열증식중인 정모세포군을 관찰할 수 있다. 이후 소엽내강에는 상당수의 초기 정세포를 관찰할 수 있으며, 더욱 더 발달된 변태된 정자를 볼 수 있다. 투과전자현미경에 의한 관찰에서 간기의 정원세포는 세포질이 미약한 반면, 커다란 핵과 뚜렷한 인을 가진다. 제1정모세포의 핵내에서는 연접사 복합체 (synaptonemal complex)가 뚜렷하고 세포질내에서는 세포소기관이 증가한다. 제2정모세포의 핵질은 응축되어 높은 전자밀도를 나타낸다. 정세포는 세포질과 핵질이 응축되면서 타원형의 형태를 취하고, 미토콘드리아는 핵의 후방으로 위치한다. 변태를 마친 정자는 두부와 미부로 구성되며 무첨체형이다. 두부 후방에서는 cytoplasmic collar는 6개의 미토콘드리아를 가진다. 미부에서는 axonemal lateral fin을 관찰할 수 있다. 미부 편모 축사의 횡단면은 "9+2"의 미세소관 구조를 나타낸다.

• 한국미생물·생명공학회지
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• 제33권1호
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• pp.1-8
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• 2005

Since Anton van Leeuwen­hoek first observed a surface-associated multicellular structure of bacterial cells in the 17th century, it has been shown to exhibit an ability to form a biofilm by numerous bacterial species. The biofilm formation is composed of distinct developmental stages, which include an attachment/adhesion of a single cell, a proliferation toward monolayered coverage, a propagation to aggregated microcolony, a maturation to 3-dimensional structure, and subsequently a local degradation. Investigation to identify the essential factors for bacterial biofilm formation has been performed via classical genetic approaches as well as recently developed technologies. The initial stage requires bacterial motility provided by a flagellum, and outermembrane components for surface signal interaction. Type IV-pilus and autoaggregation factors, e.g., type I-fimbriae or Ag43, are necessary to reach the stages of monolayer and micro colony. The mature biofilm is equipped with extracellular polymeric matrix and internal water-filled channels. This complex architecture can be achieved by differential expressions of several hundred genes, among which the most studied are the genes encoding exopolysaccharide biosyntheses and quorum-sensing regulatory components. The status of our knowledge for the biofilms found in humans and natural ecosystems is discussed in this minireview.

• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.15-20
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• 2010

A Gram negative, aerobic, nonspore-forming, straight or curved rod-shaped bacterium, designated Gsoil $317^T$, was isolated from soil of a ginseng field in Pocheon Province (South Korea) and was characterized using a polyphasic approach. Cells were dimorphic, with stalk (or prostheca) and nonmotile or nonstalked and motile, by means of a single polar flagellum. Comparative analysis of 16S rRNA gene sequences revealed that strain Gsoil $317^T$ was most closely related to Caulobacter mirabilis LMG $24261^T$ (97.2%), Caulobacter fusiformis ATCC $15257^T$ (97.1 %), Caulobacter segnis LMG $17158^T$ (97.0%), Caulobacter vibrioides DSM $9893^T$ (96.8%), and Caulobacter henricii ATCC $15253^T$ (96.7%). The sequence similarities to any other recognized species within Alphaproteobacteria were less than 96.0%. The detection of Q-10 as the major respiratory quinone and a fatty acid profile with summed feature 7 ($C_{18:1}\;{\omega}7c$ and/or $C_{18:1}\;{\omega}9t$ and/or $C_{18:1}\;{\omega}12t;$ 56.6%) and $C_{16:0}$ (15.9%) as the major fatty acids supported the affiliation of strain Gsoil $317^T$ to the genus Caulobacter. The G+C content of the genomic DNA was 65.5 mol%. DNA-DNA hybridization experiments showed that the DNA-DNA relatedness values between strain Gsoil $317^T$ and its closest phylogenetic neighbors were below 11%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $317^T$ should be classified as representing a novel species in the genus Caulobacter, for which the name Caulobacter ginsengisoli sp. novo is proposed. The type strain is Gsoil $317^T$ (=KCTC $12788^T=DSM\;18695^T$).

• Asian-Australasian Journal of Animal Sciences
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• 제21권2호
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• pp.181-189
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• 2008

The aim of this study was to evaluate the effects of $Ca^{2+}$, $HCO_3{^-}$ and BSA on the in vitro capacitation-associated protein tyrosine phosphorylation, hyperactivation and acrosome reaction in guinea pig sperm. Caudal epididymal sperm were incubated in four different groups: modified TALP (Tyrode's albumin lactate pyruvate) or TALP without one of the medium constituents ($Ca^{2+}$, $HCO_3{^-}$ and BSA). After incubation for the required time (0 h, 0.5 h, 1 h, 3 h, 5 h, and 7 h), sperm were removed for further experiment. The capacitation effect was assessed by CTC (Chlortetracycline) staining. Western blotting and indirect immunofluorescence were used to analyze the level and localization of tyrosine phosphorylation. The results showed that guinea pig sperm underwent a time-dependent increase in protein tyrosine phosphorylation during the in vitro capacitation and the percentage of protein tyrosine phosphorylated sperm increased from 36% to 92% from the beginning of incubation to 7 h incubation. Also, there was a shift in the site of phosphotyrosine-specific fluorescence from the head of sperm to both the head and the flagellum. Moreover, an absence of $Ca^{2+}$ or $HCO_3{^-}$ inhibited in vitro hyperactivation and acrosome reaction and decreased the phosphorylation of the proteins throughout the period of in vitro capacitation. However, an absence of BSA could not influence these processes if substituted by polyvinyl alcohol (PVA) in the medium.

• Journal of Microbiology and Biotechnology
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• 제20권2호
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• pp.415-424
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• 2010

The purpose of this study was to investigate the relationship between the global regulatory mechanism known as quorum sensing and expression of virulence factors in Escherichia coli O157:87. A nonpolar luxS deletion was introduced into the chromosome of strain CI03J, a human clinical isolate from South Korea, to create the ${\Delta}luxS$ mutant strain ML03J. Phenotypic characterization of wild-type and mutant strains demonstrated that ML03J had no obvious growth or metabolic defects on 0.2% glucose LB medium, produced a functionally defective flagellum, and could not utilize sorbose; the biological significance of sorbose utilization is unknown. Omics-based analysis revealed the involvement of LuxS in the transcriptional activation of several flagella/chemotaxisrelated genes (flhD; fliA, C, D, S, Z; and cheA, Y, Z), repression of glutamate-dependent acid resistance genes (gadAB), and expression of virulence factors including Shiga toxin, hemolysin, and SepD within the LEE pathogenicity island.

• Animal cells and systems
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• 제11권2호
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• pp.141-146
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• 2007

Cantharidin is produced by blister beetles (Coleoptera: Meloidae) and smaller oedemerid beetles (Coleopetra: Oedemeridae) and is found in hemolymph and various tissues. The function of cantharidin in the courtship behaviour of meloids had never been fully established. Our studies show a correlation between density of cuticular pores and cantharidin titre of the scape and pedicel segments of male specimens of the East African species of Epicauta nyassensis (Haag-Rutenberg, 1880) (Coleoptera: Meloidae). Light microscopy of semi-thin cross sections of the male scape and pedicel indicates that there are many canal shaped structures that stretch from the antennal hemolymph to the antennomere surface. These structures may be tubules, which transport cantharidin circulating in the hemolymph to the surface, where the compound can be released via cuticular pore openings. Analyses of the head capsule and antennal segments of E. nyassensis females which had been copulated with males revealed low titre of cantharidin in the first two antennal segments. The density of the scape and pedicel pores of females was to some extent higher than the density of these pores on flagellum; however it was considerably lower than that of the males. Interestingly, no tubular cell or other transport structures were found in the cross sectioning of the female antennomeres or on the integument surface. During mating, male antennomeres, as well as cantharidin containing pores which are located on the $1^{st}\;and\;2^{nd}$ antennomeres, come into direct contact with the female antennae and may release cantharidin to their surface. Female E. nyassensis may be able to discriminate the opposite sex with abundant reserves of cantharidin prior to mating. This is another evidence that cantharidin function in close range sexual selection.

• 한국패류학회지
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• 제21권2호
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• pp.95-105
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• 2005

Gonadosomatic index, reproductive cycle, spermatogenesis and first sexual maturity of Chlamys farreri were investigated by cytological and histological observations, from January 1998 to December 1999. The gonadosomatic index (GSI) rapidly increased in April and reached a maximum in May when seawater temperature rapidly increase. Then the GSI gradually decreased from June to August when spawning occur. Accordingly, monthly changes in the GSI in males coincide with the reproductive cycle. The spermatozoon of Chlamys farreri is the primitive type found in external fertilization species. The head of the spermatozoon is approximately $2.75{\mu}m$ in length including the acrosome measuring about $0.50{\mu}m$ in length, and its tail was approximately $20{\mu}m$, the axoneme of the tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. Five spherical mitochondria around the centriole (the satellite body) appear in the middle piece of the sperm. The spawning period was from June to August and the main spawning occurs from July to August when seawater temperatures are greater than $20^{\circ}C$ The reproductive cycle of this species can be categorized into five successive stages; early active stage (January to March), late active stage (March to April), ripe stage (April to August), partially spawned stage (June to August), and spent/inactive stage (August to January). Over 50% of male scallops attained first sexual maturity between 50.0 and 60.0 mm in shell height, and 100% of those over 60.0 mm in shell height achieved maturity. Accordingly, we assume that male individuals begin reproduction at three years of age.