Image of the Month 2015

December - Blood vessels in the human retina form on a scaffold of astrocytes

December 2015 - Blood vessels in the human retina form on a scaffold of astrocytes

Image by Sam Ahn, Discipline of Anatomy

This image shows a small patch of the inner surface of an adult human retina

The green label shows capillaries of the retinal circulation, specifically of the innermost layer of that circulation. The capillaries form along a scaffolding of astrocytes (red label).

Developmentally, astrocytes spread over the inner surface of the retina from the optic nerve, to lay this scaffold, just prior to the formation of the retina’s blood vessels.

The formation of vessels is induced by a period of hypoxia of the developing retina; this induces the astrocytes to express a powerful angiogenic factor, VEGF. This ensures that the vessels form and form along astrocyte processes.

This relationship is important because the astrocytes also induce barrier properties in the vessels. Disturbances of this relationship during development cause damaging deficiencies in the retinal circulation, as in retinopathy of prematurity.

Human retina from a male adult, labeled with a lectin for blood vessels (green) and with an antibody to the cytoskeletal protein GFAP (red), which is expressed specifically by astrocytes.

Imaged on a Zeiss LSM 520 confocal microscope

November - Heart development in the mouse embryo

November 2015 - Heart development in the mouse embryo

Image by Carmine Gentile, Heart Research Institute

Nkx2.5 is one of the earliest markers for heart precursor cells. Nkx2.5 expression (green) cannot be detected at this age, because of the early stage of heart development.
High levels of the enzyme eNOS are present (red), suggesting a role for eNOS in a heart development.

A mouse embryo aged E10 (10th day of embryonic life)
The embryo is labeled in three ways:
. Cell nuclei are labeled blue; they show the morphology of the embryo
. The enzyme endothelial nitric oxide synthase (eNOS) is labeled red
. The homeodomain factor Nkx2.5 is labeled green

The image is a projection of a stack of images collected by confocal microscopy

October - A sensory organ reconstructed

October 2015 - A sensory organ reconstructed

Image by Daniel Brown, Neuro-Otology Group, Brain and Mind Centre

The cochlea is a complex spirally organized sensory organ, for hearing. It is embedded in the hardest bone in the body, the petrous (stony) part of the temporal bone.

To visualize it requires specialized techniques and, in this case, a reconstruction from a stack of images captured by a specialized form of microscopy (light sheet microscopy)

The cochlea of a guinea pig cochlea was perfused in vivo with a fluorescent dye (rhodamine). The surrounding bone was decalcified and cleared. The block of cleared tissue, containing the cochlea, was viewed as a series (or stack) of images obtained by light sheet microscopy, at intervals up and down the specimen. This image was reconstructed from the image stack, in Drishti software using the MASSIVE imaging platform.

September - Separations

September 2015 - Separations

Image by Leyla Fouani, Molecular Pharmacology and Pathology Group, Discipline of Pathology

The image shows cells from a ductal pancreatic tumour. The tumour had metastasized to the liver; these cells are from the secondary tumour in the liver.

The red labeling in the cytoplasm of the cells identifies a molecule that is suspected to facilitate metastasis.

One cell (the one with the yellow labeling) is at an advanced stage of dividing into two cells (technically, it is in the anaphase of mitosis). The yellow colour results from the colocalisation of red (facilitator molecule) and green (α-tubulin) fluorescence. α-tubulin is a tubular protein that forms a framework along which chromosomes move during cell division.

The separation of chromosomes along this framework creates the two ‘rocket-ship’ figures, separating to form the nuclei of two daughter cells.

Below this actively dividing cell are two cells just formed by an earlier mitotic division; they appear just joined by residual α-tubulin (green) processes.

Pancreatic cancer is a highly lethal disease, due to the propensity of the cancerous cells to divide and migrate (metastasise) to other organize.

Image obtained by confocal microscopy.

August - A Parasitic Wasp

August 2015 - A Parasitic Wasp

Image by Gerry Shami

This image consists of 35 individually acquired images that have been manually aligned to form a complete montage of a parasitic wasp. The images were captured using a high-resolution field scanning electron microscope.

July - Interaction Between Haematopoietic and Epithelial Cells of the Yolk Sac

July 2015 - Interaction Between Haematopoietic and Epithelial Cells of the Yolk Sac

Image by Henry Williams

Even in a mammal like the mouse (and humans), the developing embryo is surrounded by a membrane called the yolk sac, because it evolved from the membrane which surround the yolk of bird’s eggs.

The sac becomes vascularised (develops blood vessels) during development. The process begins with blood precursor (haematopoietic) cells contacting the outer surface of the yolk sac.

In this image, taken with a scanning electron microscope, haematopoetic cells (shown in red) are making contact with the epithelial cells which form the outer surface of the sac. It is a critical moment in the development of every successful mammalian newborn.

Mouse embryo, 10.5 days after conception.

June - Neurones in the cerebral cortex of the mouse brain

June 2015 - Neurones in the cerebral cortex of the mouse brain

Image by Kristie Smith, Brain and Mind Research Institute

The areas shown include neocortex (top left) and the hippocampal and dentate gyri (lower right)

Technical: The mouse is from a strain bred with a marker which makes nerve cells fluoresce brightly. Some of the extensions (dendrites) of the nrve cells are shown. The marker labels the neuron-specific molecule Thy-1.

The area shown is from a 5mm thick slice of a mouse brain, which has been prepared (cleared) for optical sectioning in an ultramicroscope, in the Bosch Institute's Advanced Microscopy Facility. A stack of images was collected and merged to produce this image.

May - Medulla of a rat adrenal gland

May 2015 - Medulla of a rat adrenal gland

Image by Polina Nedoboy

Adrenal medulla of a rat adrenal gland was labelled with anti-tyrosine hydroxylase antibody (yellow); adrenal cortex (blue). Scale bar 100 μm. Image was taken with Zeiss Axio Imager .Z2 fluorescence microscope, 10x objective.

April - Murine microglia under chronic inflammatory conditions

April 2015 - Murine microglia under chronic inflammatory conditions

Image by Carsten Minten, School of Molecular Bioscience, The University of Sydney

Single murine microglia (tomato lectin stain, green) under chronic inflammatory conditions within the cerebellum of mice. Cells are not ramified as they are highly activated. Transcription factor IRF8 (red, Alexa-594), DAPI staining of nuclei (blue). Bar = 5 µm.

March - Specialised cells of the retina of the eye

March 2015 - Specialised cells of the retina of the eye

Image by Michael Lovelace and Richard Sarafian, Chan-Ling Lab (Anatomy & Histology)

The green-labelled cells are 'oligodendrocyte precursor cells'; that is, they are glial cells and not nerve cells, and they are believed to mature into a class of cell called oligodendrocytes (the name means 'cells with a few processes'). They make the insulating myeling sheaths important in nerve conduction, and also envelop blood vessels.

The precursor cells are labelled with a specific antibody marker, with a green tag. The blue label is a non-specific label taken up by all cell nuclei. The retina, in this case from a rabbit, has proved a very useful ‘window’ into the structure and function of the brain.

Technical: The specific antibody is O4, tagged with Alexa 488; the scale bar represents 100µm.

February - Finding an Anchorage Site

February 2015 - Finding an Anchorage Site

Image by Iman Roohani, Biomaterials & Tissue Engineering Lab

An adipose derived stem cell, cultured on a micropatterned hydroxyapatite ceramic, is stretching to bridge the pore and find a site to attach.

January - The Circuitry of Memory

January 2015 - Image of the Month

Image by Mustafa Kassem, Balleine Lab (Brain & Mind Research Institute)

Neuroscientists have established that memory 'resides' in a specialised area of the cortex (the surface layers) of the brain, called the hippocampus. (The folds formed by this tissue looks like a sea-horse in cross-section; 'hippocampus' is Latin for seahorse.

Memory is coded by nerve cells in the hippocampus. The largest neurones involved are called pyramidal cells, and a row of three is shown here, made visible by a silver-impregation method.

Each cell has a 'body' which is triangular in cross-section (shaped like a pyramid in three dimensions), from which long processes extend in a characteristic pattern. Each process is studded with small spines. They are called synaptic spines because other neurones make contact (synapse) onto the spines.

Memory is established and maintained by these neurone-to-neurone connections.