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AN OUTSTANDING FOOD SOURCE OF VITAMIN C
873 The curious features of the growth of C. trachomatis described here may possibly be more relevant to the progressive nature, pathology, and high contagiousness of C. trachomatis infections of the genital and ocular mucosa of patients than is the limited and relatively undramatic growth of this agent in McCoy cells. Department of Medical Microbiology, University of Liverpool, Royal Liverpool Hospital, Liverpool L69 3BX
D. HOBSON N. LEE
E. QUAYLE E.E.BECKETT
AN OUTSTANDING FOOD SOURCE OF VITAMIN C
SIR,-We have found, in a wild fruit, fifty times as much vitamin C as is present in oranges, and this may be the richest natural source of this vitamin in the world. In our study of the nutritional composition of bushfoods used by Australian Aboriginalsl,2 samples are collected by Aboriginal health workers and others and airfreighted to Sydney. In three samples of Terminalia ferdinandiana we found ascorbic acid contents of 3150, 2850, and 2300 mg per 100 g edible fruit. The samples came from three different areas near Darwin (Northern Territory) in two successive seasons, 1981 and 1982. We used reverse phase high performance liquid chromatography on two prepacked 25 cm’Lichrosorb RPB’ 10 m columns connected in series with a 3 cm guard column. The mobile phase is water with pH adjusted to 2 - 5 with metaphosphoric acid and detection is by a spectrophotometer at 245 nm. Any dehydroascorbic acid is converted to ascorbic acid. We confirmed values for ascorbic acid in T. ferdinandiana fruit by dinitrophenylhydrazine and dichloroindophenol methods.
Growth of C. trachomatis (BK strain) in coverslip and BGM cells.
cultures of McCoy
Both were inoculated in parallel with BK strain at 10- dilution = 19 000 inclusions per McCoy culture. Incubation 72 h at 35°C (see text). Glemsastained films examined by dark-ground microscopy (x400). Arrows mark cytoplasmic inclusions of C. trachomatis.
The main advantage of cycloheximide-treated BGM was not so much in the consistently higher count of inclusions but in their markedly altered appearance. Whereas inclusions in McCoy cells after 48 or 72 h were rounded and only slightly expanded the cell, those in BGM expanded the cell to 3-4 times its uninfected size and were more densely packed with elementary bodies, giving more intense dark-ground fluorescence (figure). On incubation beyond 72 h, inclusions in McCoy increased only moderately in size and became increasingly empty of elementary bodies and burst, thus reducing the count, whereas inclusions in BGM continued to grow to sizes and shapes we have never previously encountered with C. trachomatis in any other cell line under any cultural conditions. By 6 days, they formed a mass of large irregularly shaped sacs, still packed with elementary bodies, protruding between and over uninfected cells. The monolayer also contained many smaller inclusions, suggesting the possibility of secondary growth cycles, but we have yet to confirm by stepwise growth curves whether these were merely late starters. However, progressive growth of both BK and wild strains seems to occur in the sense of continuous enlargement of well-filled inclusions and marked scattering of free elementary bodies from bursting sacs across the monolaver. We are now assessing BGM alongside McCoy in our routine diagnostic service to find whether the larger and progressively more obvious inclusions and their greater number in BGM are maintained, and allow easier detection of low-grade infection, or an increase in the percentage of patients with suspected infections which can be confirmed without the tedious long scrutiny, and blind serial passage sometimes necessary, with McCoy cells.
Terminalia spp. are tropical trees of the Combretaceae family (to which the almond also belongs). T ferdinandiana, Excell ex S. T. Blake is a tall slender tree growing up to 10 m with large green-toyellow leaves. It is found along the north-west coast of Australia. The fruit grows along the branches and matures from March to August; it is about 2 cm long and 1 cm in diameter, light green to yellow in colour and contains a single large pip. It looks and tastes like an English gooseberry. Near settlements or camps all the fruit on the trees is eaten, especially by children. It is not a staple food nor one for which a special expedition might be made. One Aboriginal name for the fruit is manmohpan, in the language of people in Western Arnhem Land. Citrus fruits have around 50 mg vitamin C per 100 g; at 100 mg or above come (uncooked) broccoli, sprouts, kale, cauliflower, parsley, nettles, green mango, and kiwi fruit; around 200-300 mg are blackcurrants, guavas, peppers, cashew fruit pulp, some tropical vegetables, and a few bush fruits. At the top of the league table of vitamin C, expressed in mg per 100 g raw food, are sea buckthorn (Hippophae rhamnoides, 450’), ambla or emblic (Emblica officinalis, 6004), rosehips (Rosa canina, 12503), dattock fruit (Detarium senegalense, 12905), and acerola or Barbados cherry (Malpighia
punicifolia, 10006
to
23307).
We thank the Australian Institute for Aboriginal Studies for financial support; Ms Robin Lion and colleagues and Mr Clyde Dunlop for collecting samples; and Mr G. Hutchison, Mr L. Lawler, Dr Dermot Smyth, and Captain L. J. Hiddins for advice.
Human Nutrition Unit and Commonwealth Institute of Health,
Sydney University, Sydney, N S.W. 2006,
Australia
BRAND VIC CHERIKOFF ANNA LEE A. STEWART TRUSWELL
JENNIE C.
Lee A. The nutritional composition of Aboriginal bushfoods. Proc Nutrition Soc Aust 1981, 6: 170. 2 Brand JC. Rae C, McDonnel J, Lee A, Cherikoff V, Truswell AS Food Technology in 1.
Brand JC, Shelley C, McDonnell J,
Australia, 1982 (in press) SW, Fachman W, Kraut H. Food composition and nutrition tables 1981/82. Stuttgart Wissenschaftliche Verlagsgesellschaft, 1981 Gopalan C, Rama Sastri BV, Balasubramanian SC. Nutritive value of Indian foods. National Institute of Nutrition, Hyderabad, 1981 Leung W-TW, Busson F, Jardin C. Food composition table for use in Africa. Rome:
3. Souci 4 5
FAO, 1968. Food composition tables: Minerals and vitamins for international use. Rome FAO, 1954. 7. Wenkam NS Miller CD Composition of Hawaii fruits Univ Hawaii Agric Exp Stat Bull 1965, no 135. 6 Chatfield C
D. HOBSON N. LEE
E. QUAYLE E.E.BECKETT
AN OUTSTANDING FOOD SOURCE OF VITAMIN C
SIR,-We have found, in a wild fruit, fifty times as much vitamin C as is present in oranges, and this may be the richest natural source of this vitamin in the world. In our study of the nutritional composition of bushfoods used by Australian Aboriginalsl,2 samples are collected by Aboriginal health workers and others and airfreighted to Sydney. In three samples of Terminalia ferdinandiana we found ascorbic acid contents of 3150, 2850, and 2300 mg per 100 g edible fruit. The samples came from three different areas near Darwin (Northern Territory) in two successive seasons, 1981 and 1982. We used reverse phase high performance liquid chromatography on two prepacked 25 cm’Lichrosorb RPB’ 10 m columns connected in series with a 3 cm guard column. The mobile phase is water with pH adjusted to 2 - 5 with metaphosphoric acid and detection is by a spectrophotometer at 245 nm. Any dehydroascorbic acid is converted to ascorbic acid. We confirmed values for ascorbic acid in T. ferdinandiana fruit by dinitrophenylhydrazine and dichloroindophenol methods.
Growth of C. trachomatis (BK strain) in coverslip and BGM cells.
cultures of McCoy
Both were inoculated in parallel with BK strain at 10- dilution = 19 000 inclusions per McCoy culture. Incubation 72 h at 35°C (see text). Glemsastained films examined by dark-ground microscopy (x400). Arrows mark cytoplasmic inclusions of C. trachomatis.
The main advantage of cycloheximide-treated BGM was not so much in the consistently higher count of inclusions but in their markedly altered appearance. Whereas inclusions in McCoy cells after 48 or 72 h were rounded and only slightly expanded the cell, those in BGM expanded the cell to 3-4 times its uninfected size and were more densely packed with elementary bodies, giving more intense dark-ground fluorescence (figure). On incubation beyond 72 h, inclusions in McCoy increased only moderately in size and became increasingly empty of elementary bodies and burst, thus reducing the count, whereas inclusions in BGM continued to grow to sizes and shapes we have never previously encountered with C. trachomatis in any other cell line under any cultural conditions. By 6 days, they formed a mass of large irregularly shaped sacs, still packed with elementary bodies, protruding between and over uninfected cells. The monolayer also contained many smaller inclusions, suggesting the possibility of secondary growth cycles, but we have yet to confirm by stepwise growth curves whether these were merely late starters. However, progressive growth of both BK and wild strains seems to occur in the sense of continuous enlargement of well-filled inclusions and marked scattering of free elementary bodies from bursting sacs across the monolaver. We are now assessing BGM alongside McCoy in our routine diagnostic service to find whether the larger and progressively more obvious inclusions and their greater number in BGM are maintained, and allow easier detection of low-grade infection, or an increase in the percentage of patients with suspected infections which can be confirmed without the tedious long scrutiny, and blind serial passage sometimes necessary, with McCoy cells.
Terminalia spp. are tropical trees of the Combretaceae family (to which the almond also belongs). T ferdinandiana, Excell ex S. T. Blake is a tall slender tree growing up to 10 m with large green-toyellow leaves. It is found along the north-west coast of Australia. The fruit grows along the branches and matures from March to August; it is about 2 cm long and 1 cm in diameter, light green to yellow in colour and contains a single large pip. It looks and tastes like an English gooseberry. Near settlements or camps all the fruit on the trees is eaten, especially by children. It is not a staple food nor one for which a special expedition might be made. One Aboriginal name for the fruit is manmohpan, in the language of people in Western Arnhem Land. Citrus fruits have around 50 mg vitamin C per 100 g; at 100 mg or above come (uncooked) broccoli, sprouts, kale, cauliflower, parsley, nettles, green mango, and kiwi fruit; around 200-300 mg are blackcurrants, guavas, peppers, cashew fruit pulp, some tropical vegetables, and a few bush fruits. At the top of the league table of vitamin C, expressed in mg per 100 g raw food, are sea buckthorn (Hippophae rhamnoides, 450’), ambla or emblic (Emblica officinalis, 6004), rosehips (Rosa canina, 12503), dattock fruit (Detarium senegalense, 12905), and acerola or Barbados cherry (Malpighia
punicifolia, 10006
to
23307).
We thank the Australian Institute for Aboriginal Studies for financial support; Ms Robin Lion and colleagues and Mr Clyde Dunlop for collecting samples; and Mr G. Hutchison, Mr L. Lawler, Dr Dermot Smyth, and Captain L. J. Hiddins for advice.
Human Nutrition Unit and Commonwealth Institute of Health,
Sydney University, Sydney, N S.W. 2006,
Australia
BRAND VIC CHERIKOFF ANNA LEE A. STEWART TRUSWELL
JENNIE C.
Lee A. The nutritional composition of Aboriginal bushfoods. Proc Nutrition Soc Aust 1981, 6: 170. 2 Brand JC. Rae C, McDonnel J, Lee A, Cherikoff V, Truswell AS Food Technology in 1.
Brand JC, Shelley C, McDonnell J,
Australia, 1982 (in press) SW, Fachman W, Kraut H. Food composition and nutrition tables 1981/82. Stuttgart Wissenschaftliche Verlagsgesellschaft, 1981 Gopalan C, Rama Sastri BV, Balasubramanian SC. Nutritive value of Indian foods. National Institute of Nutrition, Hyderabad, 1981 Leung W-TW, Busson F, Jardin C. Food composition table for use in Africa. Rome:
3. Souci 4 5
FAO, 1968. Food composition tables: Minerals and vitamins for international use. Rome FAO, 1954. 7. Wenkam NS Miller CD Composition of Hawaii fruits Univ Hawaii Agric Exp Stat Bull 1965, no 135. 6 Chatfield C