Abstract Image analysis of suitably demarcated fruiting pedicels of Cyclamen hederifolium has revealed that the coiling of the pedicel subtending the fruiting body involves a resumption of growth in the mature organ. The distribution of resurgent growth is highly selective, both spatially and temporally, and involves a polar migration down the convex side of the organ, while the corresponding region on the concave side undergoes compression. The nature of the response is considered in relation to other plant movements.
Light affects the growth and orientation of roots of cress seedlings (Lepidium sativum L. cv. Curled). The effects are manifest either as increased rates of geotropic curvature or, if the roots are horizontal, as distorted and crinkled forms of growth. Blue, red, and far-red irradiation can bring about these effects, but with differences of detail: at equal fluence rates during the period of geostimulus, blue is more effective than red at increasing the rate of geocurvature; however, with irradiation prior to a geostimulus, only the stimulatory effects of red irradiation persist for 2–4 h of darkness. Short periods (5 min) of radiation, if given at the time of geostimulus, enhance geocurvature, again with blue most, and far-red least, effective, but there are no clear indications of red/far-red reversibility. The possibility of there being more than one photosystem responsible for the effects of white light on the geotropic responsiveness of roots is discussed.
The electron microscopic image and some properties of a filamentous component of plant extracts are described. The filaments are 3·5 nm in diameter, non-rigid and present a beaded appearance when positively stained with uranyl and lead salts. They are present in the microsomal supernatant fractions of a variety of plants, and can be obtained in extracts of fresh tissues or of acetone powder preparations. Specific tissues, successfully extracted for filaments, include phloem, xylem and cortical parenchyma. They are not present in extracts of cell wall preparations or of hair cells of cotton bolls. An outstanding characteristic of these filaments is their great stability to a wide variety of treatments which includes variation in temperature, ionic environment, pH and the presence of urea, thiol reagents or the detergent Nonidet. Lateral aggregation of the filaments is evident below pH 3·0 and above pH 8·0. Although cellulase was the only enzyme of those tested which digested the filaments, it is unlikely, for several reasons, that the filaments are a form of pure cellulose. Hydroxyproline was present in all filament fractions after partial purification by various methods. The filaments are discussed in relation to known fibrillar components of plant cells.
Summary Background Anti‐drug antibodies are associated with treatment failure to anti‐TNF agents in patients with inflammatory bowel disease (IBD). Aim To assess whether immunogenicity to a patient's first anti‐TNF agent would be associated with immunogenicity to the second, irrespective of drug sequence Methods We conducted a UK‐wide, multicentre, retrospective cohort study to report rates of immunogenicity and treatment failure of second anti‐TNF therapies in 1058 patients with IBD who underwent therapeutic drug monitoring for both infliximab and adalimumab. The primary outcome was immunogenicity to the second anti‐TNF agent, defined at any timepoint as an anti‐TNF antibody concentration ≥9 AU/ml for infliximab and ≥6 AU/ml for adalimumab. Results In patients treated with infliximab and then adalimumab, those who developed antibodies to infliximab were more likely to develop antibodies to adalimumab, than patients who did not develop antibodies to infliximab (OR 1.99, 95%CI 1.27–3.20, p = 0.002). Similarly, in patients treated with adalimumab and then infliximab, immunogenicity to adalimumab was associated with subsequent immunogenicity to infliximab (OR 2.63, 95%CI 1.46–4.80, p < 0.001). For each 10‐fold increase in anti‐infliximab and anti‐adalimumab antibody concentration, the odds of subsequently developing antibodies to adalimumab and infliximab increased by 1.73 (95% CI 1.38–2.17, p < 0.001) and 1.99 (95%CI 1.34–2.99, p < 0.001), respectively. Patients who developed immunogenicity with undetectable drug levels to infliximab were more likely to develop immunogenicity with undetectable drug levels to adalimumab (OR 2.37, 95% CI 1.39–4.19, p < 0.001). Commencing an immunomodulator at the time of switching to the second anti‐TNF was associated with improved drug persistence in patients with immunogenic, but not pharmacodynamic failure. Conclusion Irrespective of drug sequence, immunogenicity to the first anti‐TNF agent was associated with immunogenicity to the second, which was mitigated by the introduction of an immunomodulator in patients with immunogenic, but not pharmacodynamic treatment failure.
Abstract. Growth rates throughout an organ curving phototropically under continuous, unilateral while light were monitored by lime‐lapse photography of cress hypocotyls marked into 1 mm sections by two rows of ion‐exchange beads. Curvature resulted from an integrated sequence of changes in growth rate on each side of the organ, but the actual patterns of change and, therefore rales of curvature, differed within even this one species, depending upon the immediate pretreatment of the seedlings. Transference of seedlings from darkness to unilateral irradiation gave immediate growth inhibition on both sides of the organ. Curvature resulted from differential recovery of growth rate, being seen first on the shaded side, most prominently in the apical regions; only 2h after initial exposure to light did growth recover on the lit (lower) side. On the other hand, transfer of seedlings from omnilateral to unilateral irradiation of the same intensity resulted in simultaneous growth inhibition on the irradiated side and stimulated growth on the shaded side: this growth stimulation of the shaded side was greater than occurred in totally darkened control plants.
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