Protonema of the moss Funaria hygrometrica can function as a lead (Pb) adsorbent.

Water contamination by heavy metals from industrial activities is a serious environmental concern. To mitigate heavy metal toxicity and to recover heavy metals for recycling, biomaterials used in phytoremediation and bio-sorbent filtration have recently drawn renewed attention. The filamentous protonemal cells of the moss Funaria hygrometrica can hyperaccumulate lead (Pb) up to 74% of their dry weight when exposed to solutions containing divalent Pb.

In vitro bioassay of allelopathy of by sandwich method and protoplast co-culture method with digital image analysis.

We examined the allelopathic activities of , ecotype Columbia by two in vitro methods. The effect of dried leaves on the growth of recipient lettuce seedlings was examined by the sandwich method. The allelopathic activity on protoplast growth was examined by co-culture with recipient lettuce leaf protoplasts in 50 µl liquid medium using a 96-well culture plate.

Electron probe X-ray microanalysis studies on the distribution change of intra- and extracellular calcium in the elongation zone of horizontally reoriented soybean roots.

To clarify the contribution of Ca to the gravitropic response, quantitative X-ray microanalyses were performed on cryosections of roots of soybean seedlings reoriented horizontally from their original vertical orientation. After reorientation, the roots bent gradually toward the ground at the elongation zone. The concentrations of Ca in the cell walls, cytoplasmic matrices and central vacuoles of cortical cells were measured in the upper and lower halves of the elongation zone at 0, 30, 60 and 120 min after reorientation.

Effect of NaCl on ionic content and distribution in suspension-cultured cells of the halophyte Sonneratia alba versus the glycophyte Oryza sativa.

The effect of a high concentration of NaCl on the intra- (cytoplasmic matrix and vacuole) and extracellular (cell wall) distribution of Na, Cl, K, Mg, Ca, S, and P was investigated in suspension-cultured cells of the mangrove halophyte Sonneratia alba and compared to cultured cells of glycophytic rice (Oryza sativa). No significant differences were observed in ultrastructural features of cluster cells of both species cultured with and without 50mM NaCl. Quantitative X-ray microanalysis of cryosections of the cells cultured in the presence of 50mM NaCl showed that the Na concentration ([Na]) and Cl concentration ([Cl]) significantly increased in all three cell components measured.

Properties of lead deposits in cell walls of radish (Raphanus sativus) roots.

Various mechanisms are involved in detoxification of heavy metals such as lead (Pb) in plant cells. Most of the Pb taken up by plants accumulates in their roots. However, the detailed properties of Pb complexes in roots remain unclear.

Cytochemical and electron probe X-ray microanalysis studies on the distribution change of intracellular calcium in columella cells of soybean roots under simulated microgravity.

The columella cells of soybean roots grown under gravity and simulated microgravity induced by a clinostat were examined using potassium pyroantimonate (PA) and quantitative X-ray microanalysis of cryosections to determine the role of Ca in the regulation of the gravitropic response. Amyloplasts in the columella cells were localized exclusively at the bottom under gravity, but diffusely distributed in the cytoplasmic matrix under simulated microgravity, thus supporting the statolith theory. In the columella cells, PA precipitates containing Ca were diffusely distributed in the cytoplasmic matrix under gravity.

Unphosphorylated twitchin forms a complex with actin and myosin that may contribute to tension maintenance in catch.

Molluscan smooth muscle can maintain tension over extended periods with little energy expenditure, a process termed catch. Catch is thought to be regulated by phosphorylation of a thick filament protein, twitchin, and involves two phosphorylation sites, D1 and D2, close to the N and C termini, respectively. This study was initiated to investigate the role of the D2 site and its phosphorylation in the catch mechanism.

Intracellular calcium translocation during the contraction-relaxation cycle in scorpionfish swimbladder muscle.

To examine intracellular Ca(2+) translocation during the contraction-relaxation cycle in vertebrate striated muscle, electron probe X-ray microanalysis was performed on the swimbladder muscle (SBM) fibres of a scorpionfish Sebastiscus marmoratus. The SBM fibres were rapidly frozen at rest, during contraction and at various times after the onset of relaxation. Changes in calcium distribution in the components of the sarcoplasmic reticulum (SR) were examined on the SBM fibre cryosections.

Rigor-force producing cross-bridges in skeletal muscle fibers activated by a substoichiometric amount of ATP.

Isometric skinned muscle fibers were activated by the photogeneration of a substoichiometric amount of ATP and their cross-bridge configurations examined during the development of the rigor force by x-ray diffraction and electron microscopy. By the photogeneration of approximately 100 microM ATP, approximately 2/3 of the concentration of the myosin heads in a muscle fiber, muscle fibers originally in the rigor state showed a transient drop of the force and then produced a long-lasting rigor force (approximately 50% of the maximal active force), which gradually recovered to the original force level with a time constant of approximately 4 s. Associated with the photoactivation, muscle fibers revealed small but distinct changes in the equatorial x-ray diffraction that run ahead of the development of force.

Ultrastructural organization of the transverse tubules and the sarcoplasmic reticulum in a fish sound-producing muscle.

The ultrastructural basis for the extremely rapid contraction-relaxation cycle (up to 300 s(-1)) in the swim-bladder muscle (SBM) of a scorpionfish (Sebastiscus marmoratus), producing characteristic sounds for communication, was investigated by electron microscopy. The SBM fibres contained well-developed sarcoplasmic reticulum (SR) showing triadic contacts with well-organized transverse tubules (T tubules). It was newly found that different types of triadic contacts were present within the single SBM fibre.