자료유형  

 학위논문

Control Number  

0016932571

International Standard Book Number  

9798379825010

Dewey Decimal Classification Number  

612

Main Entry-Personal Name  

Eason, Julius.

Publication, Distribution, etc. (Imprint  

[S.l.] : Purdue University., 2020

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2020

Physical Description  

1 online resource(105 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-01, Section: A.

Dissertation Note  

Thesis (Ph.D.)--Purdue University, 2020.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Typhaea stercorea, also known as the hairy fungus beetle, is a secondary invasive species that has the potential to become a devastating insect pests of stored grain products. This beetle feeds on an array of fungi growing on stored grains and vectors mycotoxigenic fungi throughout the storage structures. During storage, stored grains are contaminated by fungi that can produce mycotoxins causing serious health risks to humans and animals. Residing in the alimentary canal of fungivorous insects there is a diverse bacterial community that produces key enzymes that support the shift to fungal diets. Studies have shown that bacterial communities possess mycolytic properties against fungi found residing in the alimentary canal of their host and produce chitinases that breakdown the cells wall of fungi, and in return, produce essential amino acids that contribute to the evolutionary success of fungivorous insects. Therefore, it is believed that T. stercorea feeding predominately on fungal diets has selected for unique bacterial communities with mycolytic properties. Many of these gut microbes are opportunistic and can influence their host's fitness in different ways, such as providing beneficial services that affect physiology, immune defenses, or nutrition factors contributing to the insect's growth and survival. Therefore, the main objectives of this study were to (1) charaterize the microbial community residing in the alimentary canal of T. stercorea across life stages and in lab vs. field populations, (2) learn the impact of antimicrobials on the microbial community found in the alimentary canal, and (3) determine the impact of antimicrobial-induced changes in the gut microbial community on host lifecycle and fecundity. The microbial composition survey showed that there is low bacterial diversity in the alimentary canal of T. stercorea across life stages. For alpha diversity, there were no differences across life stage, including larvae and adults. In contrast to the lack of alpha diversity, there were differences between the beta diversity of gut microbiota across life stages. For all developmental stages, the most dominant phylum was Proteobacteria in larvae and adults (98.45% and 97.30%, respectively), followed by Actinobacteria and Firmicutes. In addition, Pseudomonas spp., which belong to the phylum Proteobacteria, were differentially abundant across life stages. Next the microbiota from the alimentary canal of laboratory strain specimens (larvae and adults) were compared to field-collected adults. As expected, the microbial gut composition of adult field populations was different compared to laboratory-reared larvae and adults. Field populations possessed several known chitinolytic bacteria belonging to the families of Bacillaceae and Enterobacteriacea. The family Enterobacteriacea,which belongs to the phylum Proteobacteria represented the highest relative abundance in laboratory-reared and field-collected adults.Next, for Objective 2 antimicrobials were used to cause changes in the composition of intestinal microbiota to investigate the association between bacteria and host physiology. Ampicillin (25 µg/ml), kanamycin (12.5 µg/ml), and tetracycline (3.12 µg/ml) were tested for their effects on gut microbial diversity. All antimicrobials significantly reduced the culturable gut bacteria populations from larvae, but did not decrease culturable bacteria populations from adults. Next the gut microbial communities at different life stages were characterized, treating T. stercorea larvae and adults with antimicrobials. Members that belong to the family Enterobacteriaceaewere most dominant in the larvae and adults, followed by the genus Pseudomonas.

Subject Added Entry-Topical Term  

Physiology.

Subject Added Entry-Topical Term  

Fungi.

Subject Added Entry-Topical Term  

Pathogens.

Subject Added Entry-Topical Term  

Humidity.

Subject Added Entry-Topical Term  

Feeds.

Subject Added Entry-Topical Term  

Success.

Subject Added Entry-Topical Term  

Bacteria.

Subject Added Entry-Topical Term  

Amino acids.

Subject Added Entry-Topical Term  

Grain.

Subject Added Entry-Topical Term  

Crops.

Subject Added Entry-Topical Term  

Diet.

Subject Added Entry-Topical Term  

Biology.

Subject Added Entry-Topical Term  

Agriculture.

Subject Added Entry-Topical Term  

Agricultural commodities.

Subject Added Entry-Topical Term  

Chitinase.

Subject Added Entry-Topical Term  

Wheat.

Subject Added Entry-Topical Term  

Rice.

Subject Added Entry-Topical Term  

Insects.

Subject Added Entry-Topical Term  

Antimicrobial agents.

Subject Added Entry-Topical Term  

Harvest.

Subject Added Entry-Topical Term  

Adults.

Subject Added Entry-Topical Term  

Barley.

Subject Added Entry-Topical Term  

Nonnative species.

Subject Added Entry-Topical Term  

Atmospheric sciences.

Subject Added Entry-Topical Term  

Food science.

Subject Added Entry-Topical Term  

Microbiology.

Added Entry-Corporate Name  

Purdue University.

Host Item Entry  

Dissertations Abstracts International. 85-01A.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:642914