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Photograph by Ron Oldfield, Macquarie University, See http://dx.doi.org/10.1093/aob/mcs295
The image shows sporophytes and calyptras of Funaria hygrometrica, a water moss (photograph by Ron Oldfield, Macquarie University). The calyptra is a gametophytic tissue that covers the tip of the elongating sporophyte. A young sporophyte with an intact calyptra appears in the lower left corner, whilst other sporophytes are in the process of shedding their calyptras or have already shed them. The calyptra is proposed to function, in part, as a maternal constraint on capsule expansion, as an expression of parent–offspring conflict.
This is a video of a flour mill with two stones in a small shop outside the gates of Punjab Agricultural University, Ludhiana, India. The film shows the grain being poured into the hoppers above the stones, and then going between the millstones. From one stone set, the brown/wholemeal flour goes into sacks; in the other, it goes straight onto a shaking sieve, with the bran and germ going to the back and the white flour coming out of the front of the sieve. It is then collected and bagged, here in 10kg sacks, for use without further grinding or bleaching. The mill also makes maize meal and gram (lentil/chickpea) flour. The wheat flour will be mostly used for making chapati (chappati) or roti breads, thin dough cooked on a heated stone. The flour has high gluten content to give the elasticity to the dough so it can be stretched to be thin.
In the west, most flour is milled using multi-stage roller mills that first remove the bran and germ, and then grind the flour/starch/endosperm, usually slightly finer that this mill. In this shop, the separation of the two stones can be adjusted to change fineness while they are running, a process not shown in the video. In the Punjab and Ludhiana, there were several similar roadside shops for flour mills (some with only one stone pair), and other shops which crushed oilseeds for oil and meal.
This videoblog from www.AoBBlog.com is about one of the Cell and Developmental Biology practicals that I run at the University of Leicester for course #BS1003. It involves infection of carrot root slices with three strains of Agrobacterium, two of which cause the plant cells to divide. An earlier video showed how we set up the cultures www.youtube.com/watch?v=mS6OjCekrNo ; here we review the results and look at the Agrobacterium plasmid structure.
Plant development can be disrupted dramatically by certain pathogens. Here, we saw how the bacterial pathogen, Agrobacterium tumefaciens, causes tumours on differentiated plant tissues by activating cell division. The process involves the transfer of bacterial genes into the plant chromosomes at wound sites, resulting in the genetic transformation of the plant cells which then divide in an uncontrolled fashion because they have incorporated the genes for hormone production into the carrot cells. These genes are located in a circular DNA molecule present in the wild type Agrobacterium tumefaciens known as T37. This is the Ti plasmid, some 206,000bp long. The part that is transferred into the nuclear DNA of the carrot is known as the T-DNA and it contains the genes which make the hormones that induce the plant cells to divide. A different group of genes – both for hormones and controlling plant developement – are present in Agrobacterium rhizogenes and these lead to production of differentiated roots from the carrot cells at the site of wounding – in our case cutting – the root tissue. The third strain of Agrobacterium tumefaciens that we used was similar to the wild type T37 but it had the genes for hormone production removed.
Practical Booklet Introduction:
Cell proliferation and organogenesis mediated by Agrobacterium
Plant and animal development can be perturbed by disease. Both plants and animals can suffer oncogenic diseases, in which the normal control over cell division is lost and tumours form. In plants, species of the soil bacterium Agrobacterium cause disease symptoms in infected plants that are characterised by tumours, the so-called Crown Gall disease (Agrobacterium tumefaciens) or by the aberrant production of ‘hairy roots’ (Agrobacterium rhizogenes). The disease symptoms are caused by the transfer from the bacteria, and expression in the plant nucleus, of genes carried on a circular DNA molecule (a plasmid, the ‘tumour-inducing’ Ti-plasmid; or the ‘root-inducing’ Ri-plasmid), following excision and transfer of part of that plasmid. This transfer of genes from bacterium to plant represents a natural form of genetic engineering, and has been exploited experimentally as a means of modifying plant growth, development and metabolism, for both basic and applied research purposes.
Plant tumour tissues are characterised by an ability to grow on media lacking hormones, since the genes transferred from the bacteria to the plant cells encode genes that promote the synthesis of auxins and cytokinins.
In this experiment you will inoculate plant tissues (carrot tap roots) with three different strains of Agrobacterium, and study the effects on the infected tissue. The explants will be maintained on a minimal culture medium that contains no added hormones. Therefore, any callus or other outgrowth of the explants will be determined by the transforming effect of the bacteria.
LBA4404 [control] = a ‘disarmed’ A. tumefaciens strain (lacking hormone biosynthesis genes).
T37 = a wild type A. tumefaciens strain.
LBA9402 = a wild type A. rhizogenes strain.
SUMMARY OF RESULTS
In the carrots which were used as control, with no infection with the Agrobacterium, there has been a minimal amount of cell division on the surface cells, and the tissue looks slightly dry. In the carrots with the so-called disarmed strain, LBA4404, there as also been minimal growth and division of the cells. The other two have extensive cell division and proliferation, in the case of Agrobacterium rhizogenes, differentiating to form roots.
In one of the biotechnology lectures, I discussed the T-DNA structure a little more and another clip I will upload soon will show parts recorded live from this lecture, summarizing some of the material discussed above and in this video.
Virtual studios and video blogs: I’ve produced and edited my first videoblogs, and here I’m going to give some indications of how they were made. The videoblogs mean I can tell you about interesting things in plant sciences and about my work, and explain informally some of the stories around the things we publish in Annals of Botany or on AoBBlog.com. Please watch in HD if you have a fast internet connection.
Please watch in HD if you have a fast internet connection.
Did you know that YouTube is the third most visited website in the world, after Google at number 1 and Facebook, and ahead of Yahoo, Baidu (the Chinese search giant) and Wikipedia at 6th (www.Alexa.com). YouTube is an important source of information as well as entertainment – so I think it is very important that organizations have a presence there. My content is related to scientific research, so won’t draw huge audiences, but it is important that my work is available in this channel, and as editor of a not-for-profit, charitable, plant science journal, I want to make sure our content can reach another audience through that channel and tell people about interesting news in botany too.
I’m Pat Heslop-Harrison with another videoblog for AoBBlog.com
Lots of people have been asking me about the virtual studio setup I used. Well, it has amazed me how access to technology has moved on. When I first started photography, getting anything – even different types of film – was expensive and meant talking to patronizing types from the likes of KP Professional or Calumet, who went out of their way to be unhelpful, had minimal knowledge even of what they sold let alone the manufacturers ranges, and meant then shelling out vast amounts of money for slightly the wrong thing.
Fortunately, now both information and products are available easily on the internet, and the combination of energy efficient lights and far better high speed photography makes everything easier. So making a studio, and then editing videos is very straightforward. There are three excellent computer programs for video editing – Sony Vegas, FinalCutPro and Adobe Premiere. All do more or less the same thing, and I happened to use Adobe Premiere largely because of my familiarity with Photoshop, which I use daily for microscopy and imaging in my lab.
The video editing methods let you build up a virtual studio, with you as presenter, a digital studio, and images or other videos showing everything you are talking about. In my case, as presenter I am sitting or standing in front of a backdrop which is a colour contrasting with my clothes and skin – a greenscreen. As shown already, we then use a process called keying to make this background transparent, and then you are presented in front of any image you chose – the virtual studio. As in many real studios, I decided to put a framed clear area within this background for more, changing, images. You then end up with a series of layers – me presenting, the studio wall, and the image on the screen. You can cut between these and change sizes and positions independently.
Some surprising points are just how many images you use in a short video clip – the three cover videoblogs with about 8 minutes total time had 104 different image, video and sound files. While writing the material is no more difficult, nor any easier, then for written blogs, you do need a lot of extra pictures for a video blog – 10 to 15 file ‘assets’ per minute of YouTube time. The usual problem is finding pictures: my computer has about 83,000 photographs from digital cameras, I have about 30,000 slides, and then another 120,000 digital and film micrographs from microscopes. I had hoped that the video blog format might be faster than the written format, but that certainly is not the case – the editing time alone is about an hour per minute of output.
I hope this format will be useful to learn more about interesting science!
The third in a series of videoblogs from AoBBlog.com about the background pictures used on Annals of Botany covers.
The Youtube link is here, and it is best watched in HD/1080p resolution. An outline of the text is below the video insert below, and the text includes some extra links.
A shrubby tree, Plumeria ?rubra from the Apocynaceae featured as the background on the 2011 Annals of Botany cover. The picture was taken in the Brazilian cerrado. The adaptation to fire with the bark and rapid sprouting following the first rains after the fire is clear. This is an exceptional ecosystem with many species. While most people think about the threats to the Amazon forests and its conservation, those to the cerrado are less discussed and potentially as severe, with replacement of the vegetation with crops. Interestingly, one of the most downloaded papers from Annals of Botany each of the last three years has been from 1997 – yes, 1997 when downloads were hardly used – but clearly representing a manuscript well ahead of its time ( http://tinyurl.com/AoBcerrado )! Again, the GPS-encoded location from the Plumeria shows it was photographed to the south west of Brasilia, in the heart of the cerrado at 16° 5′ 39″S, 48° 17′ 00″W, and quite high at 882.3 m. It was taken about three weeks after the regular fires in the area, and a surprise for me was how rolling the cerrado ecosystem was.
Finally, we get to the launch of the new cover for 2012: the Meskel (or Meskal, Mekel) Daisy Bidens pachyloma from Ethiopia, culturally an iconic flower for the country that symbolises happiness and rebirth. It flowers for a relatively short period in early September around the time of the Ethiopian New Year and an important part of the ceremony of the finding of the true cross. The hillsides of central and Northern Ethiopia are covered with the bright yellow flowers, and it is cut and used to decorate floors and the pyres of the crosses which are then burned in joyful ceremonies around the country. In the January issue, the Meskel daisy is paired with another daisy in the inset picture – an important fossil of an extinct Eocene species from the work of Viviana Barreda in Rio Negro, Argentina ( www.dx.doi.org/10.1093/aob/mcr240 ). Altogether, a cover that symbolizes the interest of plants – from the cultural to the ecological and through to their evolution.