biology zoology blog benno meyer rochow gall genetics

Cancer Researchers & Molecular Geneticists: this could be something for you

The incredible galls

Round and red like cherries they were, the oak-apples, a kind of plant gall, which I loved to collect as a child. But they had a biting-bitter flavour, which taught me that despite their enticing looks as far as their value as a food item was concerned, they were pretty useless. A very important lesson, indeed, for not everything that’s pretty on the outside has a valuable inside. Later I also learned that not all plant galls have to be smooth, round or red. There are some that are warty, chimney-shaped, pimple-like, white and even purple in colour and they may not even be confined to the blade of a leaf. As a young, first year student (I started my university life as someone who considered math as a major, but then decided on chemistry only to change a year later to fisheries and ultimately end up in Neurobiology) I described a gall that was formed by the actions of an aphid known as the spiral gall aphid (Pemphigus spirothecae). This “plant louse” causes the stem of a poplar tree’s leaf to undergo a helical twist combined with a bulbous swelling into which the aphid settles and starts its family. The species has recently been shown to be a “social insect”, exhibiting division of labour between individuals and altruistic behaviour traits similar to those of ants and honey bees.

For centuries some galls had practical roles (as a source of ink) or found uses in homeopathy and medical compounds, but none to the best of my knowledge served as a regular component of the human diet. The principal agents in plant gall formation are the larvae of certain beetles species, plant sap-sucking aphids, flies and solitary wasps. A few small moths, some mites and nematode worms are also on record to cause gall growths. Each gall former usually has an “agreement” with one particular species of plant. Through an as yet still poorly understood mechanism the growing embryo or larva in the plant tissue manipulates the metabolism and growth machinery of the plant, so that certain cells undergo rapid proliferation (as in cancers), creating a thick coat of multi-cellular, nutritive tissue around the insect: a tissue that is out of place and out of character for the plant; hence another similarity to a cancerous growth. The plant gall, as it continues to grow and acquire colour, becomes conspicuous to other insects and some, which originally have had nothing to do with the formation of the gall, may “decide to become tenants” so that a mature gall can become the home to a dozen or so different species of insects.

It surprises me immensely that cancer researchers and molecular geneticists or even nutrition specialists have not homed in on this wondrous interplay between an animal and a plant. If we knew how the plant makes the gall, couldn’t we program a plant to produce an edible product, a kind of seedless “fruit” that did not originate from a flower? Before our eyes, the gall-inducer manipulates the plant to “do” things it would not normally do, and the plant appears defenceless. But by complying, the plant actually confines the “pest” to one localized spot rather than allowing it to crawl unrestrictedly all over it and although the plant is “persuaded” to provide some nourishment to the gall residents, it can, in the end, rid itself of the uninvited and unwanted guests: by shedding its leaves.

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zoology biology benno meyer rochow science blog calcium bones

“GFP” and Calcium

Calcium is an abundant and important element

“GFP”? No, it does not mean ‘Guns for Peace’ or ‘Golden Flower Pot’. It stands for Green Fluorescent Protein, a substance for the discovery of which the three scientists O. Shimomura, R.Tsien and M. Chalfie were awarded the Nobel Prize in Chemistry in 2008. The GFP is inextricably connected with indicating the presence of calcium ions and calcium is one of the most important elements with multiple functions in our body ad that of animals. —>

penguin easter egg meyer rochow nutrition

Easter post : The Avian Egg : Brittle, Delicate, yet Firm

The Egg : Nutritious and perfectly shaped

We are easily fascinated by the largest, fastest, strongest, ugliest…., well superlatives generally and when you examine animal tissues, you can, of course, classify cells according to their size, shape, volume, etc. The longest cells in the human body are, no doubt, certain nerve cells with their projections called axons. In the giraffe or in a whale such neurons may easily be several metres long. But the most voluminous cells overall is nowadays, after the demise of egg-laying dinosaurs, the bird egg. And while we are at it: the smallest eggs, only 1 cm in length and 0.37 g in weight, are laid by the Jamaican hummingbird Mellisuga minima.

An unfertilized egg of a bird is a single cell (tasty and nutritious), with one nucleus and a massive amount of yolk. The semi-liquid egg content is contained in a wonderwork of porous lime on a matrix of interwoven organic fibres, which together (lime and organic fibres) make up the egg shell. The shape of the egg is marvellously practical – not only from the point of laying it, but as a compromise to strength and durability. Egg shells are often cryptically coloured and therefore less conspicuous; they also have to be sufficiently strong to resist predators. But the shell’s most important task is to prevent the semi-liquid content from oozing out through the tiny pores in the shell, but at the same time allowing gas exchange of the breathing embryo inside the egg to take place without leading to water loss, i.e., dehydration. It was shown that pigeon eggs laid under very dry conditions, exhibited 30-40% less water evaporation pressures (correlated with the total number of gas exchange pores and a greater shell thickness) than eggs, which were laid under conditions in which the relative humidity of the air was not elevated and I have found that penguins also lay eggs with relatively thick egg shells, perhaps in response to the dry Antarctic climate.

On the blunt end of each egg is an air chamber whose physiological role in respiration and internal humidity control only recently has been worked out. Although present day ostriches lay by far the biggest eggs, extinct New Zealand moas had larger eggs still and the “elephant bird” Aepyornis of Madagascar, which died out only about 350 years ago, even laid eggs that weighed 10 kg, were 34 cm long and had a volume of 160 chicken eggs. There is, however, an upper size limit for an egg, because a greater volume requires thicker and stronger shells and one arrives at a point, where a hatching chick simply would not have the power to escape from its cradle – unless the parent bird helped by breaking the egg from the outside.

Eggs are a powerful symbol of life, growth, love and fertility and they play a variety of cultural roles: famously decorated Fabergé eggs come to mind; eggs as wedding gifts (the Romans knew: “omne vivum ex ovo”), but also as a food item to be avoided (by Brahmin Hindus, for example). Northern Australian Aborigines, however, are known to have feasted for weeks almost entirely on eggs during the breeding season of the magpie goose and at Easter finding, collecting and eating eggs, maybe not for weeks, unless they are made out of chocolate, is still lots of fun – that is if you are not Chinese and prefer egg jam or eggs buried for a few months in the soil with clay, ash and salt until they smell so beautifully mature and shine so deliciously enticing in sullen brown, green and purplish hues when cut in half!

penguin easter egg meyer rochow nutrition

Is Ayu waiting for the thick shell penguin egg?


© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2016.
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