Paper factor

Each correction may be applied separately. It must be noted that the application of a protein factor is essentially independent of the application of a paper factor, which accounts for deviation from Beer s law. This last correction is a systematic error due to reading on paper and can be fitted either into the scale of the photometer or into the wedge of a double-beam automatic reader. The protein factor may then be applied afterward to particular fractions. In the case of planimetric integration a corrected base line can be drawn, but this is rarely done. 

A second possibility is to divide the fractions into the albumin on one side and the globulins on the other and to apply one single correcting factor to the albumin. This factor is a compound of the protein and of the paper factor. Protein and paper errors are most important for the large and concentrated albumin fractions. Fortunately they partly compensate each other, the paper error tending to lower the albumin value and the protein error tending to raise it. We use 1.5 in our own experimental setup and multiply the amido black-albumin surface by this figure. 

In this paper factors controlling the catalytic activity in the hydrodesulfurization reaction (HDS) are discussed. The SiOa-supported phosphormolybdenum heteropolyacid (HPMo) is used as a model catalyst. Two types of the catalyst deactivation have been shown. The reversible deactivation effect is related with changes in the molybdenum valence, its 0- and 0,S-surrounding and adsorbtion of the S-containing reaction products. The HDS activity is irreversibly changed when the transformation of the catalyst phase composition is carried out ... 

In 1966, Bowers isolated the paper factor from A. balsamea, and identified it as juvabione (60, Figure 3.2).2 Administration of 5 pg of juvabione (60) to a fifth instar larva of P. apterus inhibits its normal moulting to the adult, and generates a sixth instar supernumerary nymph.2 The acid obtained by... 

Experimenting with the insect Pyrrhocoris apterus, Williams and Slama (1966) observed that the insects failed to metamorphose normally in Petri dishes lined with paper of American origin. In elucidating the reason for this chance discovery, they established that Pinaceae used in America as raw material for paper manufacture contain paper factor , a substance of morphogenetic action. This compound, which they called (-I-)-juvabione (11), was isolated by Bowers et al. (1966) and, independently, by Cemy et al. (1967). The members of this latter research group isolated a still more effective derivative, dehydrojuvabione (12) from pinewood. 

In the search for the paper factor, extracts from several gymnosperms were assayed on P. apterus fifth instars (Table 1) [83, 84, 85]. Extracts of wood and bark of a number of these conifers were also injected into pupae of the wax moth, Galleria mellonella a localized scaleless patch was observed in the pupal cuticle at the site of injection with these extracts. However, no abnormal effects on development were observed [86]. The authors speculated that this absence of activity may be attributable to the dilute concentration of active ingredients in the extracts. 

In addition to their effects on metamorphosis, these compounds also disrupt embryonic development. The viability of P. apterus eggs is severely reduced following treatment of adult females or freshly laid eggs with partially purified "paper factor" [98] this activity is not observed... 

Wigglesworth [4] confirmed that farnesol and its related compounds showed the juvenoid activity against the bloodsucking bug, Rhodnius prolixus. Slama and Williams [5] found that paper products made from balsam fir, Abies halsamea, showed juvenoid activity against hemipteran bug, Pyrrhocoris apterus, and called the compound the paper factor. The chemical structure of the paper factor was identified as a methyl ester of todomatuic acid, and named juvabione (3) [6]. 

Juvebione, paper factor a monocyclic sesquiterpene ester from the wood of the North American balsam fir (Abies balsamea). (-h)-J. is an oil, M, 266, [a] +79.5° (c = 3.5, CHCI3). J. was the first juvenile hormone isolated from a plant, and its structure was the first elucidated. It is specific for Pyrrhocoris apterus and only the dextrorotatory form is biologically active. The search for J. began when it was observed that filter paper made from the wood of the balsam fir contained a factor which produced developmental anomalies in the larvae of Pyrrhocoris. In addition to... 

The so-called paper factor responsible for insect juvenile hormone (JH) activity of certain American papers has been identified (1966) as the bisabolane methyl ester, (-h)-juvabione (155), a constituent of balsam fir, Abies balsamea (416). As a matter of fact, the acid corresponding to 155, todomatuic acid (156), had been known earlier as a component of bisulfite-treated pulp oil of Abies sachalinensis (399). Juvabione and related compounds possessing JH activity have been isolated from several species of the family Pinaceae, including (-h)-A -dehydrotodomatuic acid (157) and 7-hydroxytodomatuic acid (158) from wood of Cedrus deodara (33). 

Slama K, Williams C M 1966 Paper factor as an inhibitor of the embryonic development of the european bug Pyrrhocoris apterus. Nature 210 329-330... 

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