Intrinsic and extrinsic hatching-inducing factors

Question 1

two categories that induce hatcing

Answer 1

1. intrinsic
2. extrinsic

Question 2

harder to identify as we lack an understanding of the genes governing embryonation and hatching in many nematode species

Answer 2

intrinsic larval factors

Question 3

primary intrinsic or larva-directed strategy dor preventing untimely hatching

Answer 3

pausing or arresting development

Question 4

nematodes that enter diapuase during egg stage in response to unfavorable conditions

Answer 4

cyst nematodes

Question 5

primary cue that initiates or relieves diapuase, allowing nematodes to hatch during favourable seasons

Answer 5

temperature

Question 6

species that do not hatch one eggs have not reached the stage of full embryonation

Answer 6

• Ascaris suum
• Trichuris muris

Question 7

can also trigger developmental arrest

Answer 7

host cues or food availability

Question 8

species wherein hatching is triggered by host cues or food availability

Answer 8

Pristionchus pacificus

Question 9

halt P. pacificus embryonation

Answer 9

pheromones from living beetles

Question 10

mutants in Caenorhabditis elegans that exhibit delayed hatching as a phenotype

Answer 10

1. hch-1
2. vab-19
3. snx-3
4. ddo-3

Question 11

example of extrinsic factors

Answer 11

1. host-derived
2. environment
3. physicochemical

Question 12

species where host-gut bacteria are essential for infection

Answer 12

Trichuris spp.

Question 13

unable to hatch in germ-free mice

Answer 13

Trichuris muris

Question 14

produce greater hatching than luminal contents in T. suis

Answer 14

mucosal scrapings of gastrointestinal tract

Question 15

species wherein hatching is induced by bile (5%)

Answer 15

Ascaris suum

Question 16

species where hatching can be induced by plant diffusates

Answer 16

Globodera genus

Question 17

species that do not require host stimuli for hatching

Answer 17

majority of Meloidogyne spp.

Question 18

environmental factors that play a role in hatcing of soil nematodes

Answer 18

1. pH
2. temp.
3. oxygen availability
4. CO2
5. texture
6. moisture
7. microbial activity

Question 19

species that exhibit poor embryonation and hatching if subjected to extreme cold or heat

Answer 19

1. Aphelenchus avenae
2. Capillaria obsignata
3. Trichuris spp.
4. Ascaris spp.

Question 20

eggs that continually take up oxygen during embryonation

Answer 20

Trichuris trichiura

Question 21

chemicals that are able to induce Heterodera spp.

Answer 21

• iron
• zinc
• vanadium