Science-world news | Science Section | EDUKACJA BIOLOGICZNA I ŚRODOWISKOWA 1/2015
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Science-world news
Resurrection plants
Resurrection plants belong to a group of plants which are not connected by scientific classifica-tion, but their ability to survive conditions of ex-treme drought in desert areas.
Lack of adequate water in the environment puts the-se plants into a state of periodic cryptobiosis, or more specifically anhydrobiosis, i.e., extreme reduction of metabolism in conditions of lack of water in their en-vironment. The best known resurrection plants are:
Anastatica hierochuntica of the family Brassicaceae,
commonly known as “Rose of Jericho”, “Mary’s Flower” or “Mary’s Hand” and often confused with – Selaginella
lepidophylla of the Selaginellaceae. The first occurs in
areas of the Middle East and Sahara Desert, including Israel, Palestine, Iraq, Iran and Egypt. While Selaginella
lepidophylla is a plant characteristic of the Chihuahuan
Desert, straddling the US and Mexico border.
What is most surprising is the speed at which resurrec-tion plants, desiccated into a ball, regain their vitality following hydration. Under conditions of prolonged drought meristematic tissue, hidden in the drained parts of the plant is curled into a ball. The prevention from complete dehydration of tissues is provided by a sugar, trehalose, which binds water molecules and traps them in cells of the plant. As soon as rain falls or plants are put into water, a very rapid absorption of
wa-ter by dead cells of the ouwa-ter parts of the plant follows and after just a few minutes the uncurling of the plant’s stems can be observed – it seems as if the resurrection plant has been “brought back to life” (Fig. 1). The ability to uncurl the dead stems of the plant is due to hygro-chastic movement (a type of hygroscopic movement).
The news are prepared by the specialists from the Science Section of the Educational Research Institute
(Instytut Badań Edukacyjnych)
The water absorption into the dried parts of the plant results in an uneven saturation and swelling of the dead parts of membranes and cell walls, which leads to defor-mation of whole cells and the uncurling of shoots. This can be seen particularly well in the case of A.
hierochun-tica (Fig. 2). The reason for rapid water absorption is the
Fig. 1. The phases of „reviving” Selaginella lepidophylla
A. desiccated S. lepidophylla (right) and several minutes after putting it into the beaker of water (left) [source: https://biologiaroslin.files. wordpress.com/2011/04/mokra-sucha.jpg?w=300&h=242]; B. fully developed S. lepidophylla, after several hours in water
[source: https://biologiaroslin.files.wordpress.com/2011/04/zmartwychwstanka2.jpg?w=286&h=300].
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strong hygroscopic property of these plants. This pro-cess can be accelerated by watering a plant with a very warm water – that’s where the stories of resurrection plant watering with boiling water come from. Obvio-usly watering a plant with a hot water does not impact its vitality positively (it may affect meristematic tissues, hidden in the middle of the plant), but if someone wants to invoke the “rolling up” of the resurrection plant in a short time, this is an effective method. It should be noted that the processes of uncurling and curling the dead parts of the plant are reversible, so it rolls up into a ball after a re-dehydration.
The life cycle of the Rose of Jericho is of particular in-terest, being inextricably linked with consecutive pe-riods of drought and unexpected rainfall. The folding of shoots of the plant can already be observed at 60% water loss from the shoots and roots. It is vital that the
ripe fruits with their seeds remain inside the structure rolled up into a ball Anastatica hierochuntica (Fig. 2A). In this way the plant protects its seeds from dehydra-tion and prevents premature propagadehydra-tion. The seeds are extremely hardy and can survive dormant for many ye-ars. When rain falls during the next rainy season, it is followed by uncurling of the dry shoots (Fig. 2B). Un-der the impact of raindrops, the fruits open, releasing their enclosed seeds. If rain is insufficient, the seeds are dispersed close to the parent plant, while powerful rain-fall, associated with the formation of periodic rivers, is accompanied with dispersal over long distances. When sufficient water is available, dispersed seeds can germi-nate within a few hours and the resulting seedlings pro-duce green shoots and blossom (Fig. 2C).
The Rose of Jericho is often used in folk medicine in Egypt, Jordan and Saudi Arabia as a remedy for difficult
labour, uterine hemorrhage, asthma, dysentery, salmo-nella, colds, fever, headaches and even epilepsy. Drops of juice from fresh leaves of the Rose of Jericho are pre-scribed for conjunctivitis. It is not surprising that rese-archers became interested in the bioactive substances present in this plant.
Research has revealed that the methanol extracts of
A. hierochuntica exhibit antioxidant and
antibacte-rial activity and aqueous extracts tested in vivo sho-wed hypoglycemic effects. This plant owes its proper-ties to the high content of antioxidants, especially flavonoids such as: anastatins A and B, naringenin, eriodictyol, quercetin, (+)-taxifolin, (+)-epitaxifolin, derivatives of apigenin, luteolin and kaempferol, chlo-rogenic acids and other phenolic compounds. Alco-holic and aqueous extracts of S. lepidophylla tested on rats showed significant hepatoprotective effects
simi-Fig. 2. The phases of „revival” Anastatica hierochuntica.
A. When the stems of Rose of Jericho curl into a ball, they remain in the state of “sleep” for the entire period of drought.
B. Uncurled shoots of A. hierochuntica about half an hour after wetting with water (left) and for comparison the dehydrated plant (right). C. Green flowering Rose of Jericho with fruits (a).
[source: http://flora.org.il/en/books/plant-stories-2/chapter-e-2/useful_plants_c1/]
Science-world news | Science Section | EDUKACJA BIOLOGICZNA I ŚRODOWISKOWA 1/2015
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Crystal microflowers
Unusual-shaped micrometer size crystals have been obtained as a result of controlled precipita-tion reacprecipita-tion [1].
What do you imagine when you hear the word crystal? Some people will associate it with cube-shaped sugar crystals or with crystals grown in a jar filled with the saturated table salt solution. Others may associate this word with flat panel liquid crystal displays in which the optical effect of a liquid crystal layer is exploited. A paper published in Science Magazine [1] concerns the generation of unique flower-shaped crystals (Fig. 1). The authors state that using a dynamic reaction-diffusion process they grew microstructures made of carbonate-silica.
Put simply, it may be stated that these beautiful crys-tals grew as a result of chemical gradient changes (e.g., concentration gradients). Crystals may precipitate when a given ingredient in the solution of more than one compound is present and some local changes in physicochemical properties occur. The variable
param-eters include: pH, temperature and concentration of the substances in the solution. In the experiment scientists changed the properties of a solution containing two salts: barium chloride (BaCl2) and sodium silicate
(Na-2SiO3). They measured the influence of pH and
tempera-ture as well as the amount of the CO2 dissolved in the solution on the rate and shape of the microstructures that formed. These structures were produced in a bea-ker containing a solution of salts mentioned above, on glass plates covered with a gold layer and on aluminum plates. The CO2 concentration gradient was maintained by placing the plate at an angle (Fig. 2). The closer the area was to the surface of the solution the higher the CO2 concentration.
Crystals of barium carbonate (BaCO3) and silica (SiO2) are formed as a products of two main precipitation re-actions:
Ba2++ CO
2 + 2H2O → BaCO3 + 2H3O+ and
SiO32-+ 2H3O+→ SiO2 + 2H2O.
One can see that both the processes are pH (the pres-ence of H3O+ ions, temperature (the concentration of
lar to silybin, due to the properties of flavonoids and tannins.
Małgorzata Musialik, IBE Science Section
References
AlGamdi N., Mullen W., Crozier A., Tea prepared from Anastatica hirerochuntica seeds contains a diversity of antioxidant flavo-noids, chlorogenic acids and phenolic compounds. Phytochemi-stry 2011, 72, 248–254. DOI: 10.1016/j.phytochem.2010.11.017. Friedman J., Gunderman N., Ellis M., Water response of the
hygro-chastic skeletons of the true rose of Jericho (Anastatica hierochun-tica L.). Oecologia 1978, 32, 289-301. DOI: 10.1007/BF00345108. Hegazy A.K., Kabiel H.F., Alatar A.A., Lovett-Doust J., Plasticity in
dynamics and hygrochastic persistence in Anastatica hierochun-tica L. (Brassicaceae) populations under simulated rainfall treat-ments. Polish Journal of Ecology 2013, 61, 493-504.
Marzouk M.M., Al-Nowaihi A.-S.M., Kawashty S.A., Saleh N.A.M., Chemosystematic studies on certain species of the family Brassi-caceae (Cruciferae) in Egypt. Biochemical Systematics and Eco-logy 2010, 38, 680-685. DOI: 10.1016/j.bse.2010.04.004.
Nakashima S. et al., Melanogenesis inhibitors from the desert plant Anastatica hierochuntica in B16 melanoma cells. Bioorganic and Medicinal Chemistry 2010, 18, 2337-2345. DOI: 10.1016/j. bmc.2010.01.046.
Pampurova S., Van Dijck P., The desiccation tolerant secrets of Se-laginella lepidophylla: What we have learned so far? Plant Phy-siology and Biochemistry 2014, 80, 285-290. DOI: 10.1016/j.plap-hy.2014.04.015.
Tiwari P., Ahirwae D., Chandy A., Ahirwar B., Evaluation of hepato-protective activity of alcoholic and aqueous extracts of Selaginella lepidophylla. Asian Pacific Journal of Tropical Disease 2014, 4, S81-S86. DOI: 10.1016/S2222-1808(14)60419-9.
Yoshikawa M., Xu F., Morikawa T., Ninomiya K., Matsuda H., Ana-statins A and B, new skeletal flavonoids with hepatoprotective activities from the desert plant Anastatica hierochuntica. Bioor-ganic and Medicinal Chemistry Letters 2003, 13, 1045-1049. DOI: 10.1016/S0960-894X(03)00088-X. http://flora.org.il/en/books/plant-stories-2/chapter-e-2/useful_ plants_c1 http://en.wikipedia.org/wiki/Anastatica https://biologiaroslin.wordpress.com/2011/05/04/nie-tak-do-konca--zmartwychwstanie
Fig. 1. Photographs of various structures produced as a result of a controlled crystallization process
All the photos were taken using a scanning electron microscope (SEM). All the photos are false-coloured.
Source: Noorduin WL, Grinthal A, Mahadevan L, Aizenberg J (2013). Supplementary Materials for Rationally Designed Complex, Hierarchical Microarchitectures, Science, 340: 832 (2013), modified.
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CO2 goes down when temperature rises) and concentra-tion of ions (Ba2+ and SiO
32-) dependent.
The scientists from Harvard University not only dem-onstrated the procedures of microstructure production but also how to control their shape. For example, they showed how the word hello could be printed in those microcrystals using the Morse code alphabet (Fig. 3). Some people might think that these experiments are just a hobby or for fun. They should know, however, that results of this work are highly relevant to branches of industry such as optics or electronics. Those who are
Fig. 2. Experimental setup used to produce microstructures
Abbreviations: a – substrate on which the microcrystals was grown, b –BaCl2 and Na2SiO3 solution. Orange arrow shows the direction of CO2 flow. Source: Noorduin WL, Grinthal A, Mahadevan L, Aizenberg J (2013). Rationally Designed Complex, Hierarchical Microarchitectures. Science, 340: 832, modi-fied.
still not convinced about the value of this kind of work should know that not long ago liquid crystals were con-sidered a useless state of matter and now they dominate the plat-panel display market [3].
Marcin M. Chrzanowski, IBE Science Section
References
Noorduin WL, Grinthal A, Mahadevan L, Aizenberg J. Rationally Designed Complex, Hierarchical Microarchitectures. Science, 340: 832.
Antoni Adamczyk, Niezwykły Stan Materii Ciekłe Kryształy, 1979 Wiedza Powszechna, Warszawa.
Fig. 3. Phrase hello Morse coded in the microobjects crystal structure
Source: Noorduin WL, Grinthal A, Mahadevan L, Aizenberg J (2013). Rationally Designed Complex, Hierarchical Microarchitectures. Science, 340: 832, modified.
Is ADHD a fictitious disease?
On March 26 this year the publication of the con-troversial book written by dr. Richard Saul “ADHD Does Not Exist: The Truth About Attention Deficit and Hyperactivity Disorder” will be announced on the Polish market. The author, a neurologist with over fifty years of experience presents his belief that ADHD is not really a single condition, but a cluster of symptoms that can accompany more than 20 different diseases and disorders, ranging from poor eyesight to depression and bipolar di-sorder.
The book shocked the medical world in the US last year, however, Dr. Saul’s claim is not entirely new. Let’s recall that back in 2009 the discussion about confession made by Dr. Leon Eisenberg (called “the father of ADHD”) swept media around the world. In his last interview with
Der Spiegel, he said that “ADHD is a perfect example of
a fictitious disease”. No matter how it sounds, both Saul and Eisenberg, wanted to draw the attention of the pub-lic to the fact that the number of children, teenagers and even adults diagnosed with ADHD in the last 10 years has increased dramatically, which may mean that some of them were given an incorrect diagnosis, based only on symptoms such as attention deficit or aggression and problems with completing tasks. Every healthy person has similar problems from time to time and it should certainly not be the signal to start the standard drug therapy used to treat ADHD.
In the article published in Time magazine, Dr. Saul said that he does not deny the fact that today people are ex-posed to more distractions than ever before and that some patients showing symptoms of attention deficit and hyperactivity really need help. He came to the con-clusion, however, that ADHD, as defined by the
Diagno-Science-world news | Science Section | EDUKACJA BIOLOGICZNA I ŚRODOWISKOWA 1/2015
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stic and Statistical Manual of Mental Disorders (DSM),
which is the classification of mental disorders adopted by the American Psychiatric Association, does not exist. Under the current definition it is sufficient to identify the presence of 5 out of 18 possible symptoms to identify a person as suffering from ADHD. When you read the list of symptoms, you may arrive at the conclusion that everybody has ADHD, because who does not someti-mes experience problems with concentration,
organiza-tion of work, forgetting things and losing objects? Who never has the feeling of distraction? Dr. Saul said that according to these subjective criteria, the entire popu-lation of the US potentially qualifies as patients with ADHD. Moreover, there are over 20 different conditions which can lead to the typical symptoms for ADHD and each requires a different approach to treatment. These include sleep disorders, undiagnosed sight and hearing defects, drug and alcohol abuse, iron deficiency, aller-gies (especially inhalant alleraller-gies and gluten intoleran-ce), bipolar disorder, depression, obsessive-compulsive disorder and even dyslexia. It is clear that the psycho-active substances prescribed in the treatment of ADHD cannot relieve the problem underlying these diseases and disorders and may even delay or prevent healing of the real condition behind the lack of concentration. In addition, drug therapy has many side effects, including
dependence on stimulants, especially dangerous in chil-dren and increased tolerance, which leads to the incre-asing the dosage to achieve the same therapeutic effect. This is because the organism, which is habituated to the intake of stimulants, stops producing adequate quanti-ties of neurotransmitters. Moreover, in many cases sti-mulants are effective only in the short term, masking or even exacerbating the true cause of attention deficit. According to Dr. Saul, there are two types of people who are diagnosed with ADHD: those who exhibit normal levels of distraction and impulsiveness, and those who have a disease or disorder which requires an individual approach. The explanations for problems for patients in the first category are most commonly: poor diet, lack of adequate sleep, excessive consumption of caffeine in the afternoon, excessive use of mobile phones and the
Fig. 1. Source: http://lowres.cartoonstock.com/education-teaching- teacher-teaching-teaches-classrooms-classroom_sizes-jmp100506_low.jpg Fig. 2. Source: https://gordonvatch-erprincipal.files.wordpress. com/2013/02/animals.jpg
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lack of a hobby. Both children and adults need challen-ge to be more involved in their work. If commitment is absent, the feeling of distraction, boredom and even de-pression may occur and so a solution to the problems of patients in this category may be an interesting job/hob-by or a healthy lifestyle. On the other hand, patients in the second category require full evaluation to identify the real cause of symptoms known as ADHD. Usually, after the root cause of the disease is treated, the symp-toms of ADHD disappear.
It is estimated that in Poland the problem of ADHD affects between 3-10% of school-age children. In the context of the revelations presented in Dr. Saul’s book, it is worth considering how many students actually have this condition and how many of them are victims of educational mistakes made by their parents and te-achers. Maybe instead of administering pills “to calm down” unruly kids, we should ask ourselves whether overcrowded classes (Fig. 1) and “teaching to the test” foster attention and encourage efficient, creative lear-ning (Fig. 2).
Małgorzata Musialik, IBE Science Section
References http://time.com/25370/doctor-adhd-does-not-exist/ http://www.nytimes.com/2014/03/12/us/report-says-medication--use-is-rising-for-adults-with-attention-disorder.html?_r=1 http://www.tokfm.pl/blogi/minor-revisions/2013/06/adhd_ eisenberg_i_niedouczeni_dziennikarze/1 http://www.poradnikzdrowie.pl/psychologia/wychowanie/adhd-co--to-takiego_36912.html
