Bacteria Symbionts of Arthopods- Lecture 14

Question 1

Common hosts for bacteria (arthropods)

Answer 1

Pea aphid, cereal weevil, Beewolf wasp

Question 2

How have arthropod genomes evolved with symbiosis

Answer 2

Genomes have decayed overtime due to reliance of host genes

Question 3

Facultative symbiont

Answer 3

Secondary symbionts, not required by the host for development, can be found in a variety of cell types, and persists outside of host cells, Transmits vertically or horizontally

Question 4

Reproductive manipulators

Answer 4

Spreads by increasing host propagation through daughters (vertical transmission), in many cases infected males sterilize uninfected females (selection for infected females)

Question 5

Obligate muralists

Answer 5

Primary symbionts, required by the host for normal development, exists in the cytoplasm of host cells, found in bacteriomes, or bacteriocytes

Question 6

Bacteriomes

Answer 6

Specialized cells for bacteria, usually fat or epithelial cells

Question 7

Bacteriocytes

Answer 7

Specialized fat cells for symbionts, many bacteria can be found in one, encased in a symbiosomal membrane

Question 8

Buchnera aphidicola

Answer 8

An insect that helps pea aphids overcome Amino acid deficits, Buchnera aphidicola has a reduced genome compared to free-living bacteria
Some amino acids use enzymes from only Buchnera aphidicola (histidine and glutamate), others use enzymes from both aphids and insect (isoleucine, valine and leucine)

Question 9

Hamiltonella defensa

Answer 9

helps defend pea aphids from predatory wasps, a facultative symbiont (exists outside bacteriomes for horizontal transmission)

Question 10

How does Hamiltonella Defensa protect aphids against predatory Wasps

Answer 10

Hamiltonella defensa has APSE prophage, which encodes insecticidal toxin that allows for defence against predatory wasps, the APSE prophage can allow aphids to acquire new traits

Question 11

Wolbachia Spp.

Answer 11

Facultative manipulator manipulates mosquito reproduction to ensure their propagation through infected females

Question 12

How do Wolbachia spp. ensure offspring of mosquitos are female?

Answer 12

(1) feminization, genetic males develop as females
(2) Pathogenesis, eliminates males from reproduction
(3) Male killing eliminates males to advantage of surviving female siblings
(4) Cytoplasmic incompatibility, only infected females can mate, if male is only party infected, eggs will not hatch

Question 13

Advantages of Wolbachia in mosquitos

Answer 13

prevents the spread of dengue

Question 14

Symbionts of bee-wolf wasps

Answer 14

Antennas contain a mix of streptomyces bacteria, when wasps dig tunnels for nests, they rub their antennas to coat progeny in a substance, unhatched cocoons are protected from pathogens (i.e., mould)