• 한국잠사곤충학회지
• /
• 제23권2호
• /
• pp.11-36
• /
• 1982

본 연구는 누에의 인공사료를 개선함에 있어서 사료자원을 저렴한 가격으로 손쉽게 취득할 수 있는 방법을 연구하기 위하여 49종의 식물과 5종의 Cellulose원에 대하여 사료자원으로서의 적부를 검정하고 한편으로는 82종의 보존잠품종에 대한 계통별 섭식상황을 조사하고 또한 사육조건에 따른 섭식성의 차이와 잠체내의 효소활성과의 관계에 관하여 시험한 결과를 요약하면 다음과 같다. 1. 공시할 49종의 식물중에서 대조구(기본인공사료)보다 모진율, 2령기잠률 및 기잠체중이 더 높은 것은 동부, 오리나무, 결명차, 고구마, 토끼풀, 벚나무, 콩등이었다. 2. 모진율과 2령기잠률이 우수한 동부, 고구마. 방동산이, 오리나무 결명차, 망초구를 선발하여 전령사육을 행한 결과 대조구에 비하여 최성잠체중과 견중이 무겁고 화통비율도 더 높았으므로 이들 식물은 인공사료자원으로 이용할만한 충분한 가치가 인정되었다. 3. 인공사료조성에 첨가할 Celluloso원은 뽕나무 Cellulose가 잠체중과 견층비율이 높고 감잠비율은 낮으며 과과일수가 짧아서 가장 좋은 결과를 보여주었다. Cellulose조제방법은 NaOH처리법이 가장 간편하고 가공비도 절약되었다. 4. 우리나라 보존잠품종 82종의 인공사료에 대한 섭식성은 잠품종에 따라 차이가 있고 계통간에도 차이가 인정되었는데 대체로 일본종계가 양호한 편이고 중국종계, 구주종계의 순이다. 5. 사료조건이 상이한 경우 즉 인공사료육에서 상엽육으로 또는 상엽육에서 인공사료육으로 전환하는 시기는 다같이 4령초기가 적당한 것으로 생각되며 3령기도 무방할 것 같다. 6. 인공사료육에 적당한 온도범위는 1~3령기는 3$0^{\circ}C$, 4~5령기는 28$^{\circ}C$로 밝혀졌으며 전령 27$^{\circ}C$도 거의 비슷한 사육결과를 보여 주었다. 7. 잠품사별, 사육온도별 그리고 사료원별로 Esterase 및 Phosphatase의 Agarose gel 전기영동상을 비교해 보면 1) 상엽육과 인공사료육잠아의 중장 Esterase영동상은 잠령기별로 서로 다르고 상엽육잠아에는 인공사료육잠아에 비하여 1~2개의 활성대가 더 많이 나타나고 있다. 2) 인공사료에 대한 섭식성이 양호한 중 15는 섭식성이 불량한 중 60희에 비하여 중장 Esterase활성대가 1~2개 더 많은 경향이 있었다. 3) 사육온도별로 3~4령잠의 중장 Esterase영동상을 비교하면 28$^{\circ}C$구는 3,4령 모두 5개활성대가 인정되었으며 35$^{\circ}C$구에서는 3령기에 4개활성대, 4령기에 6~7개의 활성대가 나타났다. 4) 중장 혈액 및 견사선의 Esterase영동상은 각기 상이하다. 즉 중장에는 5개활성대. 혈액에는 1개활성대, 견사선에는 3개활성대가 인정되며 발육 계제에 따라 활성대수에 변화가 있었다. 5) 중장 혈액 및 견사선의 Acid Phosphatase영동상을 보면 중장에는 3령잠에 1개, 4령잠에 2개, 5령잠에는 3개활성대가 인정되었으며 혈액에는 3,4령잠에 각1개, 5령잠에는 3개활성대가 인정되었다. 중잠과 혈액의 Acid phosphatase형은 잠품종간이나 사육온도간에 약간의 차이가 있기는 하지만 뚜렷하지는 않았다. 견사선에는 활성대가 나타나지 않았다.

• Parasites, Hosts and Diseases
• /
• 제55권2호
• /
• pp.193-196
• /
• 2017

This study investigated the development characteristics of Dermacentor everestianus under laboratory conditions. The time taken for D. everestianus to complete the whole life cycle was 110.2 days on average, and the average developmental durations of larvae and nymphs were 17.1 days and 29.5 days, respectively. The summation of the prefeeding, feeding, and preoviposition periods of females was 17.8 days, and the oviposition and egg incubation lasted for 18.1 days and 27.7 days, respectively. A highly positive correlation was observed between the weight of engorged female and the number of egg mass laid (r=0.947). The reproductive efficiency index and the reproductive fitness index were 7.1 and 6.1, respectively.

• Parasites, Hosts and Diseases
• /
• 제56권6호
• /
• pp.567-575
• /
• 2018

Present study was performed to describe the morphological and molecular characterization of Toxocara tanuki (Nematoda: Ascaridae) from Korean raccoon dog, Nyctereutes procyonoides koreensis, naturally infected in the Republic of Korea (Korea). Juvenile and adult worms of T. tanuki were recovered in 5 out of 10 raccoon dogs examined and the larval worms were detected in 15 out of 20 muscle samples (75%). Small lateral alae were observed on the cranial end of the body in male and female adults and 2 long spicules (3.0-3.5 mm) were characteristically observed in the posterior end of males. In SEM observation, 18 pairs of proximal precloacal, a precloacal median, a postcloacal median and 5 pairs of postcloacal papillae were uniquely revealed in the posterior portion of males, but the proximal papillae were not shown in the lateral ends of females. Molecular analysis on the 18S rRNA partial DNA sequences was revealed the same finding in both samples, adult worms and muscle larvae, which are closely related to T. tanuki. In conclusion, it was confirmed for the first time that T. tanuki is indigenously distributed, the Korean raccoon dog is acted as the natural definitive host of this nematode in Korea and the morphological characteristics of T. tanuki were shown in specific structure for single postcloacal median papilla in male.

• Ocean and Polar Research
• /
• 제26권2호
• /
• pp.351-360
• /
• 2004

To investigate latitudinal variations in the zooplankton community along the meridian line ($5^{\circ}N-12^{\circ}N$, $131.5^{\circ}W$), we measured temperature, salinity, nitrate, chlorophyll-a and zooplankton at depths above 200 m from July $10^{th}$ to $25^{th}$, 2003. For comparative analysis, data of the physico-chemical properties and chl-a were matched to the two sampling depths (surface mixed layer and thermocline depth-200 m) of zooplankton. Latitudinal differences in the mesozooplankton distribution were mainly influenced by divergence formed at a boundary line formed by currents of opposing directions, consisting of North Equatorial Current (NEC) and North Equatorial Counter Current (NECC). High concentrations of chl-a south of $9^{\circ}N$, caused by equatorial upwelling related nutrients, is thought to be affected by the role of this divergence barrier, supported by relatively low concentrations in waters north of $9^{\circ}N$. The latitudinal differences of the chl-a were significantly associated with the major groups of zooplankton, namely calanoid and cyclopoid copepods, appendicularians, ostracods, chaetognaths, invertebrate larvae, and others. And temperature significantly affected the latitudinal variation of radiolarians, siphonophores, salps and immature copepods. The latitudinal differences in the two factors, temperature and chl-a, which explained 71.0% of the total zooplankton variation, were characterized by the equatorial upwelling as well as the divergence at $9^{\circ}N$. The physical characteristics also affected the community structure and abundance of zooplankton as well as average ratios of cyclopoid versus calanoid copepods. The abundance of dominant copepods, which were consistent with chl-a, were often associated with the carnivorous zooplankton chaetognaths, implying the relative importance of bottom-up regulation from physical properties to predatory zooplankton during the study period. These results suggested that latitudinal distribution of zooplankton is primarily controlled by current-related divergences, while biological processes are of secondary importance in the northeastern Equatorial Pacific during the study period in question.

• Mycobiology
• /
• 제39권3호
• /
• pp.158-163
• /
• 2011

This study was conducted to confirm the possible use of female Yangwonjam as a host for synnemata production of Isaria tenuipes in eight local areas in Korea. Silkworm pupation rate, infection rate and synnemata characteristics of I. tenuipes were examined. Normal silkworms had a higher pupation rate than silkworms inoculated with I. tenuipes. The pupae survival percentage of normal silkworm in cocoons was 92.5~97.6%, whereas it ranged from 91.1~95.6% in silkworms sprayed with I. tenuipes. Female Yangwonjam showed the highest survival percentage at 97.6% among the silkworm varieties tested. I. tenuipes infection rate of larvae of 5th instar newly-exuviated silkworms was 89.2~90.7% in the spring rearing season and 98.2~99.3% in the autumn rearing season. Synnemata production of I. tenuipes was excellent in female Yangwonjam with an incidence rate of 98.0% followed by male Yangwonjam (94.1%) and Baegokjam (93.3%) in the spring rearing season. Synnemata living weight ranged from 1.44~0.94 g in the spring rearing season. The female Yangwonjam had the heaviest synnemata weight (1.44 g) in the spring rearing season. The synnemata of I. tenuipes produced on pupae were white or milky-white in color, and were similar in shape and color to wild synnemata collected in Korea.

• 수산해양기술연구
• /
• 제58권4호
• /
• pp.326-333
• /
• 2022

To provide information needed for managing fish resources and protecting the ecosystem of Cheonsu Bay, bimonthly variations in species composition and abundance of fish eggs and larvae were investigated. The samples were collected by using bongo net at three different stations from February 2020 to December 2021. Fish eggs were divided into Engrualis japonicas and unidentified eggs, of which Engragulis japonicus accounted for 85.6% of the total eggs collected. A total of 21 species representing 17 families and 6 orders were collected. The three dominant species were Gobiidae spp, Thryssa hamiltonii and E. japonicus and these three species accounted for 74.1% in the total number of individuals. The number of species was highest in August, 2020 and lowest in February, 2020 and 2021; the number of individuals was highest in August, 2020 and lowest in February, 2020. Temporal changes in the abundances of pelagic eggs and larval fishes corresponded with temperature.

• 한국환경과학회지
• /
• 제20권10호
• /
• pp.1243-1263
• /
• 2011

This study was carried out to determine marine environments and phytoplankton community in Deukryang Bay during the period of summer in 1987-2010. Water temperature, salinity, pH and dissolved oxygen were shown in much yearly fluctuations. In August, water temperatures in surface and on bottom were the highest, compared with average surface (24.54$^{\circ}C$) and bottom (22.90$^{\circ}C$) water temperature for 18 years in Deukryang Bay. The main reason is assumed to longer duration of sunshine during the period of August. Although the amount of the rainfall in August was the highest, significant impact of marine environment did not show. Most of dissolved inorganic nitrogen and phosphate in Deukryang were lower concentration during summer and N:P ratio also showed below 18 in Redfield. In particular, extreme increasing of N:P ratio in August was occurred by intensive precipitation. Distribution of phytoplankton community was a consistent occurrence for 18 years. The genus of Chaetoceros, Cosinodisucs and Skeletonema were regarded as the represent diatom, whereas the highest occurrence of genus among dinofagellates was Ceratium. It is thought that the relationship between phytoplankton and nutrient has a strong positive signal, although nutrients persist a little concentration and much fluctuations in marine environments were observed. High availability in phytoplankton is contributed to consistently provide the food organism of shellfish. Consequently, recent decreasing production of shellfish and seed are probably associated with higher temperature during the period of summer. However, higher temperature is also occurred ago and after 2000. On the basis of geography, Deukryang Bay had a small mouth and long channel, which is attributed to decreasing genetic diversity. It is assumed that higher temperature and lower genetic diversity have a extreme impact of larvae and shellfish for reproduction in Deukryang. It is necessary to persistently monitor based on water quality and phytoplankton community.

• Mycobiology
• /
• 제43권4호
• /
• pp.458-466
• /
• 2015

Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis.

• 수산해양기술연구
• /
• 제56권3호
• /
• pp.213-222
• /
• 2020

Species composition and seasonal variations of fish in the Five West Sea Islands in Korea, were investigated by using otter trawls and bongo nets from 2014 to 2015. During the surveyed period using an otter trawl, a total of 53 species, 147,253 ind./㎢ and 2,721,296 g/㎢ of fish were collected by otter trawls. The individual dominant species were Chaeturichthys stigmatias (30.3%), Coilia nasus (18.2%), Engraulis japonicus (12.3%), and Setipinna tenuifilis (12.2%). Moreover, the biomass dominant species in biomass were Liparis tanakae (21.3%), Beringraja pulchra (18.5%), Engraulis japonicus (8.3%) and Okamejei kenojei (8.1%). Eggs by bongo nets included 1,748 ind./1,000 ㎥ of Engraulis japonicus and 64,691 ind./1,000 ㎥ of unidentified species. A total of 15 species and 2,015 ind./1,000 ㎥ of fish larvae were collected, and the dominant species were Johnius belengerii and Pholis fangi.

• Entomological Research
• /
• 제48권6호
• /
• pp.550-558
• /
• 2018

To develop a system for the mass production of Protaetia brevitarsislarvae (Pbl), this study analyzed the oviposition characteristics of third instar Pbl through successive rearing and cold treatments. In the first generation, females laid 50 eggs each on average, and spawned higher numbers of eggs for the first 5 days but then fewer after this. However, all of the $2^{nd}$-generation females that were produced through the successive rearing of eggs from the $1^{st}$ generation did not spawn. When test insects (TI) were raised at $32^{\circ}C$, their $mean{\pm}SE$ pupal period and emergence rate were $28.4{\pm}1.9$ days and 87%, respectively. However, most individuals raised in cold treatments ($5^{\circ}C$ and $-5^{\circ}C$) without a pre-cooling period did not survive. Individuals exposed to a pre-cooling period, however, had a 7-10 days longer pupal period than those raised at $32^{\circ}C$, and their emergence rate (90%) was slightly higher. Different cold treatment temperatures ($0^{\circ}C$, $3^{\circ}C$, or $5^{\circ}C$) and periods (30 or 60 days) were tested in further experiments. The experimental group kept for 30 days at $0^{\circ}C$ and $3^{\circ}C$ had the shortest pupal period of all, and emergence rates exceeded 90% in most groups. With respect to the number of eggs spawned by the second generation females after cold treatments, the experimental groups held in cold treatments at $5^{\circ}C$ for 30 and 60 days were found to spawn the most eggs. Consequently, the experimental group kept at $5^{\circ}C$ for 30 days was the most effective set of conditions tested during the entire breeding period.