東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

The Regulation of Branched-Chain Est...

Engelgau, Philip.

Linked to FindBook

Google Book

Amazon

博客來

The Regulation of Branched-Chain Ester Precursor Biosynthesis in Ripening Fruits.

Record Type:	Electronic resources : Monograph/item
Title/Author:	The Regulation of Branched-Chain Ester Precursor Biosynthesis in Ripening Fruits./
Author:	Engelgau, Philip.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2023,
Description:	207 p.
Notes:	Source: Dissertations Abstracts International, Volume: 85-02, Section: B.
Contained By:	Dissertations Abstracts International85-02B.
Subject:	Biochemistry. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30633850
ISBN:	9798380147835

The Regulation of Branched-Chain Ester Precursor Biosynthesis in Ripening Fruits.
Engelgau, Philip.

The Regulation of Branched-Chain Ester Precursor Biosynthesis in Ripening Fruits. - Ann Arbor : ProQuest Dissertations & Theses, 2023 - 207 p.

Source: Dissertations Abstracts International, Volume: 85-02, Section: B.

Thesis (Ph.D.)--Michigan State University, 2023.

The aroma of fruits is an important indicator of ripeness to potential consumers. It is appreciated by humans as being essential to the organoleptic quality of fresh fruits. The two most consumed fruits in the United States, bananas and apples, have aroma profiles dominated by straight- and branched-chain esters. These compounds confer the characteristic flavors of these fruits. Despite the value of these esters to quality perception, their biosynthesis is still poorly understood. The central theme of this work is to understand how these fruits produce an ample supply of precursors for the biosynthesis of esters. The application of acetohydroxyacid synthase inhibitors demonstrated, through aroma and amino acid analyses of treated apple, banana, and ornamental quince, that the precursors to branched-chain esters are ultimately supplied through de novo synthesis and not from protein degradation. Inhibitor treatment, paired with 13C-labeled acetate, allowed further elucidation of biochemical networks. Sensory analysis of inhibitor-treated apples, supplemented with population genetics analyses, demonstrated that humans can detect the absence of branched-chain esters and, via breeding/propagation efforts, have selected for fruit that are capable of branched-chain ester synthesis. Inhibitor application revealed a potentially unique means for butyl ester biosynthesis in banana fruit and inspired a precursor feeding study in plantain to better understand the origins of these important aroma compounds in banana. The specific mechanisms underlying banana aroma precursor biosynthesis were also explored. Aroma, respiration, and metabolic intermediate data demonstrated a coordinated shift of branched-chain amino acid metabolism that is facilitated by the alternative splicing of two otherwise feedback-regulated enzymes, acetohydroxyacid synthase and isopropylmalate synthase. The incidence of splicing and fold-change of the alternative transcripts was localized to only fruit pulp and increased with ripening. Enzymatic assays and transient expression in tobacco indicated these alternative isoforms to be immune to feedback regulation and to be able to supply ample precursors for branched-chain ester synthesis. Banana fruit aroma biodiversity was also explored, identifying several promising cultivars for future studies. Finally, artificial banana flavor was also investigated, revealing that the ersatz flavor substitute in foodstuffs is not emblematic of the banana of the past, 'Gros Michel', nor the banana of today, 'Cavendish'.

ISBN: 9798380147835Subjects--Topical Terms:

518028
Biochemistry.
Subjects--Index Terms:

Apple

The Regulation of Branched-Chain Ester Precursor Biosynthesis in Ripening Fruits.
LDR:03695nmm a2200397 4500 001 2403424
005 20241118085731.5
006 m o d
007 cr#unu||||||||
008 251215s2023 ||||||||||||||||| ||eng d
020 $a 9798380147835
035 $a (MiAaPQ)AAI30633850
035 $a AAI30633850
040 $a MiAaPQ $c MiAaPQ
100 1 $a Engelgau, Philip. $0 (orcid)0000-0001-7181-187X $3 3773697
245 1 0 $a The Regulation of Branched-Chain Ester Precursor Biosynthesis in Ripening Fruits.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2023
300 $a 207 p.
500 $a Source: Dissertations Abstracts International, Volume: 85-02, Section: B.
500 $a Advisor: Beaudry, Randy.
502 $a Thesis (Ph.D.)--Michigan State University, 2023.
520 $a The aroma of fruits is an important indicator of ripeness to potential consumers. It is appreciated by humans as being essential to the organoleptic quality of fresh fruits. The two most consumed fruits in the United States, bananas and apples, have aroma profiles dominated by straight- and branched-chain esters. These compounds confer the characteristic flavors of these fruits. Despite the value of these esters to quality perception, their biosynthesis is still poorly understood. The central theme of this work is to understand how these fruits produce an ample supply of precursors for the biosynthesis of esters. The application of acetohydroxyacid synthase inhibitors demonstrated, through aroma and amino acid analyses of treated apple, banana, and ornamental quince, that the precursors to branched-chain esters are ultimately supplied through de novo synthesis and not from protein degradation. Inhibitor treatment, paired with 13C-labeled acetate, allowed further elucidation of biochemical networks. Sensory analysis of inhibitor-treated apples, supplemented with population genetics analyses, demonstrated that humans can detect the absence of branched-chain esters and, via breeding/propagation efforts, have selected for fruit that are capable of branched-chain ester synthesis. Inhibitor application revealed a potentially unique means for butyl ester biosynthesis in banana fruit and inspired a precursor feeding study in plantain to better understand the origins of these important aroma compounds in banana. The specific mechanisms underlying banana aroma precursor biosynthesis were also explored. Aroma, respiration, and metabolic intermediate data demonstrated a coordinated shift of branched-chain amino acid metabolism that is facilitated by the alternative splicing of two otherwise feedback-regulated enzymes, acetohydroxyacid synthase and isopropylmalate synthase. The incidence of splicing and fold-change of the alternative transcripts was localized to only fruit pulp and increased with ripening. Enzymatic assays and transient expression in tobacco indicated these alternative isoforms to be immune to feedback regulation and to be able to supply ample precursors for branched-chain ester synthesis. Banana fruit aroma biodiversity was also explored, identifying several promising cultivars for future studies. Finally, artificial banana flavor was also investigated, revealing that the ersatz flavor substitute in foodstuffs is not emblematic of the banana of the past, 'Gros Michel', nor the banana of today, 'Cavendish'.
590 $a School code: 0128.
650 4 $a Biochemistry. $3 518028
650 4 $a Horticulture. $3 555447
650 4 $a Chemistry. $3 516420
650 4 $a Plant sciences. $3 3173832
653 $a Apple
653 $a Aroma
653 $a Banana
653 $a Branched-chain
653 $a Amino acid
690 $a 0487
690 $a 0471
690 $a 0479
690 $a 0485
710 2 $a Michigan State University. $b Horticulture - Doctor of Philosophy. $3 3179726
773 0 $t Dissertations Abstracts International $g 85-02B.
790 $a 0128
791 $a Ph.D.
792 $a 2023
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30633850