การเปลี่ยนแปลงองค์ประกอบของกรดไขมันและการแสดงออกของ desaturase genes ระหว่างการงอกของสปอร์ใน Mucor rouxii ATCC 24905

Changes in fatty acid composition and expression of desaturases during sporangiospore germination in Mucor rouxii ATCC 24905

Name: เสาวรัตน์ คุณยศยิ่ง

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Mucor rouxii

; y-linolenic acid

; Desaturase gene expression

; Spore germination

Abstract: Changes in fatty acid composition and expression of desaturases were studiedduring sporangiospore germination of Mucor rouxii ATCC 24905. Under optimumcondition, spore germination completed within 4 hours started by spore swelling inthe first hour followed by germ tube emission, which lasted fbr 3-4 hours. Changesin- fatty acid composition and total fatty acid (TFA) in sporangiospores wereobserved during spore germination revealing the utilization of TFA as energy sourceand a simultaneous increase in degree of desaturation, with its highest level at thetime of germ tube emergence. It was found that C18 synthesis paralleled with theexpression of the A'-, AI2-, and the A6- desaturase genes. These 3 genes weredifferentially expressed, which corresponded to the stage of spore germination. Itrevealed that the mRNA of the AI2-and d6-desaturases were detected in ungerminatedspores and throughout germination while these of the A9-desaturase was detectedonly after the onset of germination (1-2 h). This indicated a growth-depmdentincrease of a9 transcription during the beginning of germination and the constitutiveexpression of and and ~6-desaturases.It is noticeable that the increase of y-linolenic acid (GLA) appeared to bespecific for spore germination in any condition tested, at which it reached the highestlevel at the time of germ tube emergence (i.e., sub-optimal temperatures, oxygenlimitation, absence of glucose including immature and aged spores). As GLA alwaysreached its maximum at the stage of germ tube emergence in both optimal and suboptimaltemperature, it is likely that GLA did not play role in temperature adaptationbut rather was essential in the process of spore germination. The study of restoringthe germination in slow germinating mutants (M40 and DM3) also supports thenecessity of FAs and GLA in spore germination. It was found that the addition ofeither mixed FAs or GLA to these mutants increased the efficiency of germinationand germ tube emergence. Addition of mixed fatty acids increased the germ tubeemergence of M40 from 7.6 to 35.6% (368.4% increase) and of DM3 from 18.6 to59.1% (217.7% increase) at 7 hour incubation, whereas the addition of GLA gavehigher percentage of germ tube emergence of M4O and DM3 to 439.5 and 250.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร (Bangkok)

Email: info.lib@mail.kmutt.ac.th

Name: Dr.Supapon Cheevadhanarak

Role: Supervisor

Created: 2543

Issued: 2005-10-28

Modified: 2006-05-30

วิทยานิพนธ์/Thesis

ISBN: 9746280406

BIT310

tha

DegreeName: วิทยาศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: เทคโนโลยีชีวภาพ

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

©copyrights มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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