A circadian and an ultradian rhythm are both evident in root growth of rice.

This paper presents evidence for the existence of both a circadian and an ultradian rhythm in the elongation growth of rice roots. Root elongation of rice (Oryza sativa) was recorded under dim green light by using a CCD camera connected to a computer. Four treatment conditions were set-up to investigate the existence of endogenous rhythms: 28°C constant temperature and continuous dark (28 DD); 28°C constant temperature and alternating light and dark (28 LD); 33°C constant temperature and continuous dark (33 DD); and diurnal temperature change and alternating light and dark (DT-LD). The resulting spectral densities suggested the existence of periodicities of 20.4-25.2 h (circadian cycles) and 2.0-6.0 h (ultradian cycles) in each of the 4 treatments. The shorter ultradian cycles can be attributed to circumnutational growth of roots and/or to mucilage exudation. The average values across all the replicate data showed that the highest power spectral densities (PSDs) corresponded to root growth rhythms with periods of 22.9, 23.7, and 2.1 h for the 28 DD, 28 LD, and 33 DD treatments, respectively. Accumulation of PSD for each data set indicated that the periodicity was similar in both the 28 DD and 33 DD treatments. We conclude that a 23-h circadian and a 2-h ultradian rhythmicity exist in rice root elongation. Moreover, root elongation rates during the day were 1.08 and 1.44 times faster than those during the night for the 28 LD and DT-LD treatments, respectively.

Large-volume sample on-line concentration of angiotensins in non-aqueous capillary electrophoresis.

A single step on-line concentration and separation method for peptides in non-aqueous capillary electrophoresis was developed. ACN containing 50 mM tetraethylammonium perchlorate was used as the electrophoretic medium; angiotensins I-IV were separated as a result of the differences in the magnitudes of their interactions with perchlorate anions. When the sample solution (ACN containing 0.5% trifluoroacetic acid and angiotensins) was injected as a large-volume plug, the analytes were concentrated at the inlet end of the capillary by both sweeping and stacking mechanisms; the separation procedure then started automatically without any operations such as polarity change. It was found that the concentration of analytes, injection period, and concentration of tetraethylammonium perchlorate in the electrophoretic medium were important factors for both separation and concentration efficiencies. The angiotensins were concentrated and separated with the large-volume injection of up to 80% of the effective capillary length.

Accelerated repair of a bone defect with a synthetic biodegradable bone-inducing implant.

BACKGROUND: Nothing has ever had osteoinductive capacity and degradability equivalent to that of autogenous bone, although many types of biomaterials have been developed. To address this issue, we constructed a new bone graft substitute with osteogenic potential and degradability by using porous beta-tricalcium phosphate (beta-TCP) granules, bone morphogenetic protein (BMP), and a synthetic block copolymer composed of poly-D: ,L: -lactic acid with randomly inserted p-dioxanone and polyethylene glycol (PLA-DX-PEG). In this experimental study, the bone-inducing capacity and degradation properties of the composite implant during the bone healing process were examined in vivo in a cortical and cancellous bone defect model in rabbits. METHODS: The advantages of this type of implant have been examined in a cortical bone defect model created in the distal femur of rabbits. The defects (6.5 x 5 mm) were filled with 30 mg of various implants: BMP-H [rhBMP-2, 0.0025% (w/w)], BMP-L [rhBMP-2, 0.000625% (w/w)], control A (beta-TCP alone), and control B (no implant). The distal femurs were harvested at scheduled intervals after surgery and examined for the evaluation of the bony repair of the defects by three-dimensional computed tomography and histology. RESULTS: The repair of both cortical and cancellous bone occurred predominantly in the BMP-H group, and only minor cortical bone repair and cancellous bone formation were noted in the BMP-L and control A groups. Most of the beta-TCP was resorbed in the BMP-H group at 6 weeks after surgery, whereas a significant amount of beta-TCP remained in the BMP-L and control A groups. CONCLUSIONS: beta-TCP granules coated with a BMP-retaining synthetic polymer appear to be effective in enhancing the repair of both cancellous and cortical bone defects. The early disappearance of the implanted beta-TCP and restoration of the normal anatomy of bone tissue are two notable features of this approach.

A new bone-inducing biodegradable porous beta-tricalcium phosphate.

A new type of degradable biomaterial with bone-inducing capacity was made by combining porous beta-tricalcium phosphate (beta-TCP) with a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2). The BMP delivery system consisted of a block copolymer composed of poly-D,L-lactic acid with random insertion of p-dioxanone and polyethylene glycol (PLA-DX-PEG), a known biocompatible and biodegradable material. The efficacy of this biomaterial in terms of its bone-inducing capacity was examined by ectopic bone formation in the dorsal muscles of the mouse. In the beta-TCP implants coated with the PLA-DX-PEG polymer containing more than 0.0025% (w/w) of rhBMP-2, new ectopic bone tissues with marrow were consistently found on the surface of implants. The radiographic density of beta-TCP was diminished in a time-dependent manner. On histological examination, numerous multinucleated osteoclasts with positive tartrate-resistant acid-phosphatase (TRAP) staining were noted on the surface of the beta-TCP. These experimental results indicate that beta-TCP implants coated with synthetic rhBMP-2 delivery system might provide effective artificial bone-graft substitutes with osteoinductive capacity and biodegradable properties. In addition, this type of biomaterial may require less rhBMP-2 to induce significant new bone mass.