10-P003. Analysis of morphogenetic branching using optical projection tomography

MECHANISMS OF DEVELOPMENT

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available at www.sciencedirect.com

journal homepage: www.elsevier.com/locate/modo

Advances in imaging technologies 10-P001. Studying ancient Australians: 3D anatomical atlases of Lungfish and Wallabies Silke Berger1, Peter Currie1, Jean Joss2, Marilyn Renfree3, Robert Bryson-Richardson 1

1

Cardiac wall anatomy and motion may be different among individual chamber regions and are altered in disease states in humans, such as coronary heart disease. This study aims to analyse the cardiac wall motion and velocity of different regions of the ventricle in zebrafish embryos (3 days post fertilisation).

Australian Regenerative Medicine Institute, Monash University, Mel-

Using light microscopy (x400) ventricle regions (inner mid,

bourne, Vic., Australia

outer mid, outer near bulbus arteriosus (BA), inner near BA and

2

apical region) were tracked using a video edge detection system

Department of Biological Sciences, Macquarie University, Sydney, NSW,

Australia

(Ionoptix) to determine contraction velocity (CV), relaxation

3

velocity (RV) and wall motion amplitude (WMA).

Department of Zoology, The University of Melbourne, Vic., Australia

Zebrafish (n = 22) had a heart rate of 156.3 ± 6.4 bpm and an The Australian Lungfish and the tammar wallaby are important

ejection fraction of 37.0 ± 1.7%. CV and RV were significantly fas-

species in the study of vertebrate evolution. The tammar wallaby,

ter at the apical region than at all other regions measured

Macropus eugenii, is the most amenable marsupial kangaroo species

(P < 0.05). WMA was greater at the apical region than all other

for research due to its small size, its ability to breed in captivity and

regions (P < 0.001). No differences were found between other

readily handled. It is also the subject of a genome sequencing pro-

regions. CV (mean 178.2 ± 15.5 lm/s, n = 9) was greater than RV

ject. The tammar is the best studied marsupial, especially for its,

(mean 127.2 ± 15.3 lm/s, n = 9) at the outer near BA region, but

reproduction and development including sex determination and

for other regions measured RV was faster than CV (apical region:

sexual differentiation, lactational physiology, genomic imprinting

mean RV 365.2 ± 32.4 lm/s, mean CV 261.7 ± 23.4 lm/s, n = 13).

and immunology, providing valuable insights into the evolution

This study has shown differences in regional wall motion in

and function of these processes both within marsupials and also

the wild-type zebrafish embryo ventricle. Firstly, all three param-

in eutherian mammals (including mice and humans).

eters were increased at the apical region compared to other

The endangered Australian lungfish, Neoceratodus forsteri, is a

regions. Secondly, the outer near BA region had a faster CV than

key for the study of tetrapod evolution, representing the closest

RV, while the opposite was true for other regions. This suggests

living fish species to the tetrapod common ancestor. Lungfish

that, even at this early embryonic stage, there are differences in

development is therefore of significant interest for comparative

functional

studies with extant tetrapod species.

contraction.

contributions

of

different

regions

to

cardiac

The study of these species is currently limited by the scarcity of embryonic information due to the difficulties of obtaining sam-

doi:10.1016/j.mod.2009.06.435

ples. To address this lack of information we are creating a 3D anatomical database covering development of these species that can be used as an anatomical reference and for comparative anatomy. Using optical projection tomography we create a complete 3D model from a single specimen that can be rendered and virtually sectioned. As no physical sectioning is required only a single sample is used to create virtual sections in any desired plane,

10-P003. Analysis of morphogenetic branching using optical projection tomography Kieran Short1, Mark Hodson2, Lynelle Jones1, Ian Smyth1,3

allowing vast amounts of information to be gathered from each

1

sample.

Melbourne, Vic., Australia

doi:10.1016/j.mod.2009.06.434

Department of Biochemistry and Molecular Biology, Monash University,

2

Block Software, Ingle Farm, SA, Australia

3

Department of Anatomy and Developmental Biology, Monash Univer-

sity, Melbourne, Vic., Australia

10-P002. Regional cardiac wall motion in zebrafish embryos Katherine Hamilton-Smith, Carl Tucker, Alan Japp, David Newby, Martin Denvir University of Edinburgh, Edinburgh, United Kingdom

The branching of epithelial and endothelial tissues during mammalian development is essential to the core function of the kidneys, lungs and vasculature. The ability for branched tissues to increase the surface area within organs to deliver nutrients and remove toxins is important for maximum efficiency of this exchange. A failure in branching can therefore have a detri-

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mental effect on the function of such organs. We have developed

findings of previous organ culture studies. We have also assessed

an approach using Optical Projection Tomography (OPT) to pro-

the branching of kidneys in mice with mutations in a family of

vide a rapid and accurate assessment of the branching process

genes which cause Fraser Syndrome in humans. Previously,

during kidney development in a manner not possible with

developmental kidney defects have been noted in both humans

conventional imaging systems. Our method involves the acquisi-

with the disease and mice with mutations in Fras1, Frem1 and

tion of a 3D ureteric tree followed by analysis using an automatic

Frem2 genes which exhibit a phenotype similar to that of affected

segmentation and quantification software package. We have

patients. We present a quantitative assessment of the branching

initially trialled the use of the technique on kidneys from Tgfb2

status of kidneys from these model mice.

heterozygous mice which have previously been shown to exhibit differences in ureteric tree branching in comparison with wildtype littermates in organ culture. We noticed a large decrease in branching during later stages of development, contrary to the

doi:10.1016/j.mod.2009.06.436