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New view of xylem vessels
News & Comment
TRENDS in Plant Science Vol.6 No.4 April 2001
143
In Brief
New view of xylem vessels The perception of xylem vessels as passive transporters of water will need rethinking thanks to a recent report [Science (2001) 291, 1059–1062]. Maciej A. Zwieniecki and colleagues have shown that the xylem wall consists of a hydrogel, a polymer that hydrates and expands in an ionicdependent fashion, which subsequently enhances the responsiveness of xylem. The group has shown that increasing ionic concentrations increases the flow rate in xylem vessels in a rapid and reversible manner. The flow rate is dependent on pH and the polarity of the solvent, consistent with the idea that a hydrogel is responsible for controlling the flow rate in the xylem. The swelling and shrinking of pectins, which form the hydrogel, play a role in controlling the xylem flow. TS
Mediterranean miracle plant might relieve monthly misery for millions Every month premenstrual syndrome (PMS) affects millions of women, and as many households. The symptoms of irritability, anger, headache and bloating that contribute to PMS can be so severe that they are treated with strong painkillers or even anti-depressants. Research by Rued Schellenberg et al. [Br. Med. J. (2001) 322, 134–137] suggests that an extract of Vitus agnus-castus (chaste tree) should be considered as a gentler, natural alternative treatment with relatively few side-effects. Hope, J. ( Daily Mail (UK) 19 January 2001, p. 35. NC
DNA’s disappearing act Margaret Gawienowski and colleagues (University of Illinois, Urbana-Champaign, IL, USA) told reporters that PCR showed no detectable DNA from processed corn. The group told the Champaign News-Gazette, that once corn had been cooked, strained, ground and soaked, traces of DNA disappeared. The group did not detect DNA in processed corn products such as flour, meal, starch, snacks and cereals submitted by the manufacturers. The results come at a time when controversies behind StarLink genetically modified corn (Aventis, France) forced it to be pulled from the shelves
because of concerns that the GM corn might trigger allergies in humans (United Press International, 7 February 2001). TS
Papaya male contraceptive
persuaded the Mexican government to recall the permits given to Berlin for bioprospecting. Recently elected president Vicente Fox is pushing Mexican’s congress to pass laws that would give Indians more control over their natural resources (Cox News Service, 23 January 2001). TS
Not silenced, amplified!
Image courtesy of Scott Bauer, USDA.
Papaya seed extracts might become the first plant-based oral contraceptives for males. N.K. Lohiya from Rajasthan University (Jaipur, India) announced that ‘four compounds have been isolated from papaya seeds, which have been found to be suitable for use as oral contraceptive,’ at a conference on ‘Challenges in Reproductive Health for the Millennium’. To date, studies have been conducted on rats and rabbits and preclinical trials have begun. The compounds make developing sperm immobile. ‘The effects were free of toxicity as evidenced from haematological and serum clinical parameters and reversible following withdrawal of treatment after one-year study period,’ Lohiya told reporters. The reversal of fertility occurred within 15 days to a month, and the compounds did not affect the libido of the animals during the study (FT Asia Intelligence Wire, The Hindu, 8 February 2001). TS
Bioprospecting troubles in Mexico Mexican Indians have stopped a bioprospecting project in their own backyard. The US$2.5 million multinational project’s goal was to identify and preserve the ancient Mayan knowledge of plants that the Indians use to treat a variety of ailments. The head of the project, anthropologist Brent Berlin, pledged to the Mexican villages involved that his group would evenly share all profits from the venture. However, Berlin was unable to receive support from the politically turbulent Chiapas state. One indigenous group with interests in reviving Mayan healing traditions, the Chiapas Traditional Indigenous Doctors and Midwives (COMPITCH),
Genetic modification of plants is fraught with technical problems. One of the most frustrating is ‘gene-silencing’, where the introduced genes are not expressed in the transgenic plants. The discovery of an ‘amplification promoting sequence’ in tobacco, by Nikolai Borisjuk et al. [Nat. Biotechnol. (2000) 18, 1303–1306] should help to overcome this particular barrier. The sequence both increases the number of copies of the foreign gene and stimulates expression of the coded-protein. NC
Medical research, going to pot? Devotees of cannabis have long-argued for its medicinal virtues. Now those claims are being tested in a two-year, £1 million research programme led by John Zajicek of the University of Plymouth (UK). The study, funded by the Medical Research Council of the UK, will examine whether cannabis helps to relieve the symptoms of multiple sclerosis and thus has therapeutic value for treating this debilitating condition. (http://www.plymouth.ac.uk/plymouth/ publications/prel/20010123-1.htm) NC
Practical use for immature rice A group of farmers in Japan has developed a new type of tea made from the immature leaves of rice plants. Since Japanese governmental policy has cut the number of rice paddies, farmers have to keep planting rice so that the fallow paddies do not become overgrown with weeds. The overgrowth has resulted in an increased harvest of immature rice plants. The group of farmers, called the Uonuma Study Group for Industries of the Future, developed the tea, called Uonuma Beauty, over a six month span. Concurrent research at the Niigata Agricultural Research Institute showed that young rice plants have abundant vitamin C (1.5-times more than in a lemon) and compounds that are said to strengthen the immune system. [The Daily Yomiuri (Tokyo), 6 February 2001, p. 3] TS
http://plants.trends.com 1360-1385/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved.
TRENDS in Plant Science Vol.6 No.4 April 2001
143
In Brief
New view of xylem vessels The perception of xylem vessels as passive transporters of water will need rethinking thanks to a recent report [Science (2001) 291, 1059–1062]. Maciej A. Zwieniecki and colleagues have shown that the xylem wall consists of a hydrogel, a polymer that hydrates and expands in an ionicdependent fashion, which subsequently enhances the responsiveness of xylem. The group has shown that increasing ionic concentrations increases the flow rate in xylem vessels in a rapid and reversible manner. The flow rate is dependent on pH and the polarity of the solvent, consistent with the idea that a hydrogel is responsible for controlling the flow rate in the xylem. The swelling and shrinking of pectins, which form the hydrogel, play a role in controlling the xylem flow. TS
Mediterranean miracle plant might relieve monthly misery for millions Every month premenstrual syndrome (PMS) affects millions of women, and as many households. The symptoms of irritability, anger, headache and bloating that contribute to PMS can be so severe that they are treated with strong painkillers or even anti-depressants. Research by Rued Schellenberg et al. [Br. Med. J. (2001) 322, 134–137] suggests that an extract of Vitus agnus-castus (chaste tree) should be considered as a gentler, natural alternative treatment with relatively few side-effects. Hope, J. ( Daily Mail (UK) 19 January 2001, p. 35. NC
DNA’s disappearing act Margaret Gawienowski and colleagues (University of Illinois, Urbana-Champaign, IL, USA) told reporters that PCR showed no detectable DNA from processed corn. The group told the Champaign News-Gazette, that once corn had been cooked, strained, ground and soaked, traces of DNA disappeared. The group did not detect DNA in processed corn products such as flour, meal, starch, snacks and cereals submitted by the manufacturers. The results come at a time when controversies behind StarLink genetically modified corn (Aventis, France) forced it to be pulled from the shelves
because of concerns that the GM corn might trigger allergies in humans (United Press International, 7 February 2001). TS
Papaya male contraceptive
persuaded the Mexican government to recall the permits given to Berlin for bioprospecting. Recently elected president Vicente Fox is pushing Mexican’s congress to pass laws that would give Indians more control over their natural resources (Cox News Service, 23 January 2001). TS
Not silenced, amplified!
Image courtesy of Scott Bauer, USDA.
Papaya seed extracts might become the first plant-based oral contraceptives for males. N.K. Lohiya from Rajasthan University (Jaipur, India) announced that ‘four compounds have been isolated from papaya seeds, which have been found to be suitable for use as oral contraceptive,’ at a conference on ‘Challenges in Reproductive Health for the Millennium’. To date, studies have been conducted on rats and rabbits and preclinical trials have begun. The compounds make developing sperm immobile. ‘The effects were free of toxicity as evidenced from haematological and serum clinical parameters and reversible following withdrawal of treatment after one-year study period,’ Lohiya told reporters. The reversal of fertility occurred within 15 days to a month, and the compounds did not affect the libido of the animals during the study (FT Asia Intelligence Wire, The Hindu, 8 February 2001). TS
Bioprospecting troubles in Mexico Mexican Indians have stopped a bioprospecting project in their own backyard. The US$2.5 million multinational project’s goal was to identify and preserve the ancient Mayan knowledge of plants that the Indians use to treat a variety of ailments. The head of the project, anthropologist Brent Berlin, pledged to the Mexican villages involved that his group would evenly share all profits from the venture. However, Berlin was unable to receive support from the politically turbulent Chiapas state. One indigenous group with interests in reviving Mayan healing traditions, the Chiapas Traditional Indigenous Doctors and Midwives (COMPITCH),
Genetic modification of plants is fraught with technical problems. One of the most frustrating is ‘gene-silencing’, where the introduced genes are not expressed in the transgenic plants. The discovery of an ‘amplification promoting sequence’ in tobacco, by Nikolai Borisjuk et al. [Nat. Biotechnol. (2000) 18, 1303–1306] should help to overcome this particular barrier. The sequence both increases the number of copies of the foreign gene and stimulates expression of the coded-protein. NC
Medical research, going to pot? Devotees of cannabis have long-argued for its medicinal virtues. Now those claims are being tested in a two-year, £1 million research programme led by John Zajicek of the University of Plymouth (UK). The study, funded by the Medical Research Council of the UK, will examine whether cannabis helps to relieve the symptoms of multiple sclerosis and thus has therapeutic value for treating this debilitating condition. (http://www.plymouth.ac.uk/plymouth/ publications/prel/20010123-1.htm) NC
Practical use for immature rice A group of farmers in Japan has developed a new type of tea made from the immature leaves of rice plants. Since Japanese governmental policy has cut the number of rice paddies, farmers have to keep planting rice so that the fallow paddies do not become overgrown with weeds. The overgrowth has resulted in an increased harvest of immature rice plants. The group of farmers, called the Uonuma Study Group for Industries of the Future, developed the tea, called Uonuma Beauty, over a six month span. Concurrent research at the Niigata Agricultural Research Institute showed that young rice plants have abundant vitamin C (1.5-times more than in a lemon) and compounds that are said to strengthen the immune system. [The Daily Yomiuri (Tokyo), 6 February 2001, p. 3] TS
http://plants.trends.com 1360-1385/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved.