Cellulose digestion in lower termites, mediated by carbohydrases originating from both termite and
endosymbionts, is well characterized. In contrast, limited information exists on gut proteases of lower termites,
their origins and roles in termite nutrition. The objective of this study was to characterize gut proteases of the
Formosan subterranean termite (Coptotermes formosanus Shiraki) (Isoptera: Rhinotermitidae). The protease
activity of extracts from gut tissues (fore-, mid- and hindgut) and protozoa isolated from hindguts of termite
workers was quantified using hide powder azure as a substrate and further characterized by zymography with
gelatin SDS-PAGE. Midgut extracts showed the highest protease activity followed by the protozoa extracts. High
level of protease activity was also detected in protozoa culture supernatants after 24 h incubation. Incubation of
gut and protozoa extracts with class-specific protease inhibitors revealed that most of the proteases were serine
proteases. All proteolytic bands identified after gelatin SDS-PAGE were also inhibited by serine protease inhibitors.
Finally, incubation with chromogenic substrates indicated that extracts from fore- and hindgut tissues possessed
proteases with almost exclusively trypsin-like activity while both midgut and protozoa extracts possessed
proteases with trypsin-like and subtilisin/chymotrypsin-like activities. However, protozoa proteases were distinct
from midgut proteases (with different molecular mass). Our results suggest that the Formosan subterranean
termite not only produces endogenous proteases in its gut tissues, but also possesses proteases originating from its
protozoan symbionts.
Cellulose digestion in lower termites, mediated by carbohydrases originating from both termite andendosymbionts, is well characterized. In contrast, limited information exists on gut proteases of lower termites,their origins and roles in termite nutrition. The objective of this study was to characterize gut proteases of theFormosan subterranean termite (Coptotermes formosanus Shiraki) (Isoptera: Rhinotermitidae). The proteaseactivity of extracts from gut tissues (fore-, mid- and hindgut) and protozoa isolated from hindguts of termiteworkers was quantified using hide powder azure as a substrate and further characterized by zymography withgelatin SDS-PAGE. Midgut extracts showed the highest protease activity followed by the protozoa extracts. Highlevel of protease activity was also detected in protozoa culture supernatants after 24 h incubation. Incubation ofgut and protozoa extracts with class-specific protease inhibitors revealed that most of the proteases were serineproteases. All proteolytic bands identified after gelatin SDS-PAGE were also inhibited by serine protease inhibitors.Finally, incubation with chromogenic substrates indicated that extracts from fore- and hindgut tissues possessedproteases with almost exclusively trypsin-like activity while both midgut and protozoa extracts possessedproteases with trypsin-like and subtilisin/chymotrypsin-like activities. However, protozoa proteases were distinctจาก proteases midgut (มีมวลโมเลกุลต่างกัน) ผลลัพธ์ที่แนะนำที่ฟอร์ม่อซานใต้ดินปลวกไม่เพียงแต่ ผลิตภายนอก proteases ในเนื้อเยื่อของลำไส้ แต่ยัง มี proteases ที่เกิดจากการprotozoan symbionts
การแปล กรุณารอสักครู่..
