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Distribution of Bacterial Decomposers in Lake Khuvsgul, Mongolia
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Á¤À¯Á¤ ( Jung You-Jung ) - °¿ø´ëÇб³ ȯ°æÇаú
¾Èż® ( Ahn Tae-Seok ) - °¿ø´ëÇб³ ȯ°æÇаú
Á¤´Ù¿î ( Jung Da-Woon ) - °¿ø´ëÇб³ ȯ°æÇаú
±èÁÖ¿µ ( Kim Ju-Young ) - °¿ø´ëÇб³ ȯ°æÇаú
Á¶¿µ±Ù ( Zo Young-Gun ) - °¿ø´ëÇб³ ȯ°æÇаú
ÀÓÁ¤ÇÑ ( Yim Joung-Han ) - Çѱ¹Çؾ翬±¸¿ø ºÎ¼³ ±ØÁö¿¬±¸¼Ò
ÀÌÈ«±Ý ( Lee Hong-Kum ) - Çѱ¹Çؾ翬±¸¿ø ºÎ¼³ ±ØÁö¿¬±¸¼Ò
KMID : 0364820090450020119
Abstract
µ¿ÅäÁö´ë °Å´ë ´ã¼öÈ£¿¡ ¼½ÄÇÏ´Â Á¾¼Ó¿µ¾ç¼¼±Õ ±ºÁýÀÇ »ýÅÂÇÐÀû ±â´ÉÀ» ÆÄ¾ÇÇϱâ À§ÇÏ¿©, ¸ù°ñ ºÏºÎÀÇ µ¿ÅäÁö
´ë °æ°è¿¡ À§Ä¡ÇÑ ½º±¼ È£¼ö¿¡¼, Àüü ¼¼±Õ±ºÁýÀÇ ±¸Á¶¿Í À¯±â¹°ÁúÀ» ºÐÇØÇÒ ¼ö ÀÖ´Â ¹Ì»ý¹° ±ºÁýÀÇ ±¸Á¶¸¦ ¼ö½Éº°·Î ºñ±³¡¤ºÐ¼®ÇÏ¿´´Ù. ȯ°æÀÎÀÚ ºÐ¼®°á°ú, ¼ö½É 5~10 m »çÀÌ¿¡¼ thermocline°ú chemoclineÀÌ °üÂûµÇ¾ú´Ù.Denaturing gradient gel electrophoresis (DGGE)·Î Àüü ¼¼±Õ±ºÁýÀÇ ±¸Á¶¸¦ ¼ö½Éº°·Î ºñ±³ÇÑ °á°ú 0~5 m »çÀÌ¿¡¼ ±ºÁý±¸Á¶ÀÇ º¯È°¡ Äǰí, 10 m À̻󿡼´Â Acidovorax facilis¸¦ À§ÁÖ·Î ºñ±³Àû ¾ÈÁ¤µÈ ±ºÁýÀ» Çü¼ºÇÏ¿´´Ù. 10oC¿¡¼ °íºÐÀÚ À¯±â¹° ºÐÇØ Ȱ¼ºµµ(protease, cellulase, amylase, lipase)°¡ ³ôÀº ±ÕÁÖµéÀ» Ž»öÇÏ¿© 23°³ ±ÕÁÖ¸¦ ¼±º°ÇÏ¿´´Ù. Ç¥Ãþ¼ö·ÎºÎÅÍ Acidovorax defluvii¿Í Sphingobacterium faeciumÀÌ ºÐ¸®µÇ¾ú´Âµ¥ cellulase Ȱ¼ºÀÌ ³ô¾Ò´Ù. ¼ö½É2 m, 5 m ¹× 10 m ÀÌ»óÀÇ ½Ã·á¿¡¼ ºÐ¸®µÈ ¼¼±Õ±ºÁýÀº °¢°¢, Flavobacterium succinicans, Mycoplana bullata, A. facilis°¡ ¿ìÁ¡ÇÏ¿´´Ù. F. succinicans´Â ³ôÀº protease Ȱ¼ºÀ» º¸¿´°í, ¼ö½É 5 mÀÇ M. bullata´Â protease¿Í cellulase Ȱ¼ºÀÌ ÀÖ¾úÁö¸¸, »ó´ëÀûÀ¸·Î ¾àÇÑ È°¼ºÀ» º¸¿´´Ù. ¼ö½É10 mÀÇ A. facilis ±ÕÁÖµéÀº cellulase ¶Ç´Â lipase¸¦ ¼·Î ¹èŸÀûÀ¸·Î ¹ßÇöÇÏ¿´´Ù. ¿Âµµº° ¼ºÀå¼Óµµ¸¦ ºÐ¼®ÇÑ °á°ú Ç¥Ãþ(0~5m) ¼¼±ÕµéÀº ±âȸ¼º È£³Ã¼º ¼¼±ÕÀ̾ú°í, ½ÉÃþ(¡Ã10m)¿¡¼ ºÐ¸®µÈ ±ÕÁÖµéÀº 10oC ÀÌÇÏ¿¡¼ ¼ºÀå·üÀÌ ³·¾Ò´Ù. ½ÉÃþÀÇ Àú¿Â¡¤ºó¿µ¾ç »óÅ ¶§¹®¿¡ ½ÉÃþ ¼¼±Õµé°£ÀÇ °æÀï¿¡¼ ºü¸¥ Àú¿Â ¼ºÀåÀÌ ¿ä±¸µÇÁö ¾Ê°í, »óÃþÀÇ °æ¿ì À°»ó ¶Ç´Â ½Ä¹° ÇöûũſÀ¸·ÎºÎÅÍ ¿µ¾ç¹°ÁúÀÌ °ø±ÞµÇ¹Ç·Î Àú¿Â¿¡¼ ºü¸¥ ¼ºÀå ¼Óµµ¸¦ º¸ÀÌ´Â ¼¼±ÕµéÀÌ »óÃþ¿¡ ÁÖ·Î ºÐÆ÷ÇÏ´Â °ÍÀ¸·Î ÇØ¼®µÇ¾ú´Ù. µû¶ó¼ ½º±¼ È£¼ö ¼öÃþ¿¡¼ °üÂûµÈ ¼¼±Õ±ºÁýÀÇ Á¾ ºÐÆ÷¿Í ¹°ÁúºÐÇØ ÀÛ¿ëÀÇ ¼ºÃþÈ´Â, ÇÑ³Ã´ë ºó¿µ¾ç ´ã¼ö È£¼ö¿¡¼ ºÐÇØÀÚ ±ºÁýµéÀÇ »ýÅÂÇÐÀû ±â´ÉÀÌ 0~10 m ¼ö½ÉÀÇ Ç¥Ãþ¿¡ ÁýÁßµÊÀ» ½Ã»çÇÏ¿´´Ù.
To understand the ecological function of heterotrophic bacterial community in water column of large freshwater lakes in the permafrost zone, we investigated the structure and function of bacterial community in Lake Khuvsgul, Mongolia. Species composition of overall bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments, and bacteria that can be cultured at 10oC were isolated and characterized. Based on the depth profile of environmental parameters, thermocline and chemocline were recognized at the 5~10 m zone of the water column. The stratified DGGE profile indicated that the discontinuity of water properties might influence the structure of bacterial community: band profiles in the 0~5 m zone were diverse with large change by depth, but the profile was relatively stable at the ¡Ã10 m zone, with predominance of the band identified as Acidovorax facilis. Bacterial cultures were screened for protease, cellulase, amylase and lipase activity, and 23 isolates were selected for high activity of the hydrolytic enzymes. The isolates were identified based on their 16S rRNA gene sequences. In the surface water (zero meter depth), Acidovorax defluvii and Sphingobacterium faecium with high cellulase activity were present. Flavobacterium succinicans, Mycoplana bullata and A. facilis were stably predominant isolates at 2 m, 5 m, and ¡Ã10 m depths, respectively. F. succinicans isolates showed high protease activity while M. bullata isolates showed moderate levels of protease and celluase activity. A. facilis isolates showed either cellulase or lipase activity, exclusively to each other. According to the profile of growth rates of the isolates in the temperature range of 0~42oC, the surface-zone (0~5 m) isolates were facultative psychrophiles while isolates from ¡Ã10 m depth were typical mesophiles. This stratification is believed to be due to stratified availability of organic materials to the bacterial decomposers. In the water column below the chemoline, the environment is extremely oligotrophic so that the trait of rapid growth in low temperature might not be demanded by deep-lake decomposers. The stratified distribution of community composition and decomposer activity in Lake Khuvsgul implies that ecological functions of bacterial community in lakes of cold region are sharply divided by water column stratification.
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decomposer;DGGE;hydrolytic enzymes;oligotrophic lake;psychrophiles
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