Pollen from Rape plant, as opposed to the allergen from the Rapeseed.
See: Rape seed / Rapeseed, and, Rapeseed oil / Oilseed rape
Common Names: Rape, Rapeseed, Rape seed, Canola
Brassica napus is a variable species, with three subspecies. These include the B. napus napobrassica (rutabagas / Swedes), B. napus pabularia (Siberian kale, Hanover salad, etc.), and B. napus oleifera (rape, canola, etc.).
Rape is an annual plant similar to turnip and rutabaga. It is thought that Brassica napus originated from a hybridization between the turnip (B. rapa) and kale (B. oleracea acephala). Rape originated in northern Europe and was cultivated in the Mediterranean area, but is now grown throughout the world. Canola, a selected genetic variant of rape, was developed in the late 1970's in Manitoba, Canada, as a more nutritious source of vegetable oil than rapeseed.
The rape plant is an annual/biennial growing up to 1.2 m, with turnip-like flat leaves 10 - 30 cm long, slick, and generally lobed. Unlike turnips, they have no swollen root, only a thin taproot.
The plant flowers from May to August, producing yellow, cross- shaped flowers with four petals. The flowers are hermaphrodite (have both male and female organs) and are primarily insect pollinated. The plant is also self-fertile. During the 3-4 weeks flowering period, crop fields become a conspicuous part of the rural landscape during flowering, when bright yellow flowers are produced and a characteristic odour from the released volatile organic compounds are evident.
The pollen grains are covered with a sticky lipoidal substances which results in the grains sticking together and thus reducing the ability for the pollen to be airborne for a significant period, and thus this pollen is usually a fraction of the total atmospheric pollen load. It is possible that dead grains or fragments lacking the sticky coating could become airborne. Sickle shaped pods containing tiny round seeds are produced.
Rape is cultivated in fields, but the plant may escape and grow on banks of streams, ditches and arable fields.
Rape is grown primarily for green livestock fodder, its seed oil (called colza oil), and birdseed. The oil contained in the seed of some varieties of this species can be rich in erucic acid which is toxic. However, modern cultivars have been selected which are almost free of erucic acid e.g., canola oil.
Bra n 1 (Smith 1997 ref.5058 4) (Monsalve 1997 ref.5060 5)
Characterization of OSR allergens by immunoblot revealed major allergens of 6/8 kD, 12/14 kD and in the high molecular weight range at 33, 42, 51, 58/61 and 70 kD. These results suggest that rapeseed pollen is a moderate source of allergy and may sensitize despite low pollen exposure. (Hemmer 1997 ref.1406 4)
Two low-molecular-weight allergens of 6/8 kD and 14 kD as well as a high molecular-weight cluster (27-69 kD) comprising six cross-reactive peptides could be identified. The three allergens were recognized by 50, 34 and 80% of patients, respectively. Immunoblot IgE binding to oilseed rape pollen could be totally inhibited by rye pollen and moderately by birch pollen (6/8 and 14 kD) while mugwort had little effect. An anti-profilin-specific monoclonal antibody bound specifically to a 14-kD protein in oilseed rape. Binding to the 6/8-kD rape allergen could be effectively inhibited by rAln g 2, a calcium-binding protein from alder. Periodate treatment led to a significant reduction in IgE binding to the 27 to 69-kD oilseed rape allergens indicating that carbohydrate determinants are involved in IgE binding. Oilseed rape proteins were capable to quench IgE binding to timothy grass pollen proteins of >/=60 kD suggesting that grass pollen group 4 allergens cross-react with the 27 to 69-kD cluster in oilseed rape. (Focke 1998 ref.4359 7)
OSR pollen profilin shares IgE and IgG epitopes with Bet v 2 and other plant profilins and may represent a potentially relevant allergen for profilin-sensitized patients. (Focke 2003 ref.8679 3)
Pollen allergen: three proteins were molecules of 70 kD with a pI >8, 40 kD with a pI around 10 and 80 kD with a pI around 5 have been identified. These proteins displayed identities with the berberine bridge protein, a receptor-like protein kinase and the cobalamin-independent methionine synthetase from Arabidopsis thaliana, respectively. (Chardin 2001 ref.4233 4)
A patient sensitive to Brassica pollen, reacted with a B. rapa pollen-coat protein of 7.5 kDa, a lipid-binding protein (LTP), which may indicate, that due to a taxonomical relationship, the presence of a LTP in rapeseed pollen (Toriyama 1998 ref.5103 7)
Of 18 sera studied, 5 recognized a wide multispot zone with a molecular mass around 43 kD. From this zone, two isoforms of the polygalacturonase enzyme were identified. (Chardin 2003 ref.7999 3)
IGE AND IMMUNE:
Asthma, allergic rhinitis and allergic conjunctivitis.
Type I hypersensitivity to rapeseed pollen allergens was described as the result of a cross-sensitization with various pollens that could constitute an aggravating factor in birch or grass pollen allergies. (Chardin 2003 ref.7999 3)
In this study, of patients with a history of symptoms to oilseed rape pollen, only 2 of 23 tested, showed evidence of allergy to oilseed rape and only 10 of 23 tested, including these two, were atopic. Eye, nasal, and headache symptoms increased in the season in cases, which validated the questionnaire used in the previous cross sectional survey. 12 of 16 cases tested and seven of 15 controls showed a seasonal fall in PC20; the fall in the cases was significantly greater than in the controls. Peak flow charts showed no evidence of fall or of increased variability during the season. The authors conclude that people who complained of symptoms in relation to the flowering of oilseed rape were rarely allergic to the plant and fewer than half were atopic. Nevertheless, they usually showed increased bronchial reactivity during the season, which may have been due in some cases to other allergens but in others to non-specific irritant effects of the air. (Soutar 1995 ref.1303 3)
In 4468 patients with suspect inhalant allergy investigated between June 1994 and May 1995, routine skin prick testing revealed rapeseed pollen sensitivity in 7.1% of pollen-allergic patients. In all, monovalent sensitization was detected in nine patients. (Hemmer 1997 ref.1406 3)
In 25 residents in a small Scottish village reporting symptoms when oilseed rape virtually surrounded the village, varied during the growing season of the crop and was at its highest coincident with peak flowering. At the same period of the following year when the crop was absent, symptom reporting was significantly lower. The symptoms which correlated most strongly with peak oilseed rape flowering were sneezing, cough, headache, eye irritation and the total of these and other symptoms. Increased symptoms were reported by 12 of the participants though only seven of these were judged to be atopic. The symptoms did not correlate with levels of oilseed rape pollen but there is no clear evidence as to which of the other factors associated with the crop might be the cause. (Parratt 1995 ref.5063 5)
Random samples of 1000 adults from the general practice populations of two villages surrounded by oilseed rape fields, and 1000 adults from one village far from such cultivation, were taken. On a previously validated questionnaire, there were small but significant excesses of cough, wheeze, and headaches in spring in the oilseed rape area (2.3% v 1.1%, 6.8% v 4.6%, and 4.8% v 2.8%, respectively). Counts of oilseed rape pollen were generally low except adjacent to fields. Oilseed rape was shown to give off terpenes and these were detected close to fields. (Soutar 1994 ref.5065 9)
Mill worker, farming
A low prevalence of allergy to oilseed rape pollen (less than 0.2%) unless the subjects were occupationally exposed was shown. (Fell 1992 ref.5066 8)
This studys results suggest that the inhalation of oilseed rape dust, not pollen, can cause IgE mediated bronchoconstriction (occupational asthma) in an exposed worker of the grain industry. (Suh 1998 ref.5056 0)
Irritants have been postulated as the cause for bronchospasm from contact with this plant (instead of the pollen). 22 volatile compounds were identified as being emitted during the flowering period. The main constituents were alpha-farnesene (a sesquiterpene); beta-myrcene (a monoterpene); linalool (a monoterpene alcohol) and the 'green leaf' volatile (E)-3-hexen-1-ol acetate. These compounds constituted between 50 and 87% (mean 68%) of the total volatiles emitted in all of the entrainments carried out with flowering oilseed rape plants. The remaining constituents consisted of a range of compounds including other terpenoids, the characteristic 'green leaf' volatile (E)-3-hexen-1-ol, short chain alcohols and ketones, organic sulphides and nitrogen-containing compounds. These were generally present as minor constituents but some plant entrainments revealed that higher relative amounts could be emitted. This was particularly apparent for dimethyl disulphide, 3-methyl-2-pentanone, 3-hydroxy-2-butanone, sabinene, isomyrcenol and (E)-3-hexen-1-ol. (Butcher 1994 ref.5064 8)
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Allergy Advisor - Zing Solutions
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