Do highly trained monkeys walk like humans? A kinematic study of bipedal locomotion in bipedally trained Japanese macaques

In this study, we examined the kinematics of bipedal walking in macaque monkeys that have been highly trained to stand and walk bipedally, and compared them to the kinematics of bipedal walking in ordinary macaques. The results revealed that the trained macaques walked with longer and less frequent strides than ordinary subjects. In addition, they appear to have used inverted pendulum mechanics during bipedal walking, which resulted in an efficient exchange of potential and kinetic energy. These gait characteristics resulted from the relatively more extended hindlimb joints of the trained macaques. By contrast, the body of the ordinary macaques translated downward during the single-limb stance phase due to more flexed hindlimb joints. This resulted in almost in-phase fluctuations of potential and kinetic energy, which indicated that energy transformation was less efficient in the ordinary macaques. The findings provide two insights into the early stage of the evolution of human bipedalism. First, the finding that training considerably improved bipedal walking a posteriori may explain why the very first bipeds that might not yet have been morphologically adapted to bipedal walking continued to walk bipedally. The evolutionary transition from quadrupedalism to bipedalism might not be as difficult as has been envisioned. In addition, the finding that macaques, which are phylogenetically distant from humans and in which bipedal walking is unlike human walking, could develop humanlike gait characteristics with training, provides strong support for the commonly held but unproven idea that the characteristics of the human gait are advantageous to human bipedalism.     

Purification and characterization of a feruloyl esterase from the intestinal bacterium Lactobacillus acidophilus

Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.1.1.73). In the present study, the FAE from a human typical intestinal bacterium, Lactobacillus acidophilus, was isolated, purified, and characterized for the first time. The enzyme was purified in successive steps including hydrophobic interaction chromatography and anion-exchange chromatography. The purified FAE appeared as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 36 kDa. It has optimum pH and temperature characteristics (5.6 and 37 degrees C, respectively). The metal ions Cu(2+) and Fe(3+) (at a concentration of 5 mmol liter(-1)) inhibited FAE activity by 97.25 and 94.80%, respectively. Under optimum pH and temperature with 5-O-feruloyl-L-arabinofuranose (FAA) as a substrate, the enzyme exhibited a K(m) of 0.0953 mmol liter(-1) and a V(max) of 86.27 mmol liter(-1) min(-1) mg(-1) of protein. Furthermore, the N-terminal amino acid sequence of the purified FAE was found to be A R V E K P R K V I L V G D G A V G S T. The FAE released FA from O-(5-O-feruloyl-alpha-L-arabinofuranosyl)-(1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose (FAXX) and FAA obtained from refined corn bran. Moreover, it released two times more FA from FAXX in the presence of added xylanase.     

Effect of anion binding on the thermal reverse reaction of bathoiodopsin: anion stabilizes two forms of iodopsin

The thermal reactions of the bathoproduct of the long wavelength sensitive visual pigment iodopsin were investigated under various anionic and environmental conditions, to get an insight into the mechanism leading to the unusual thermal isomerization of the retinal chromophore from the trans to the 11-cis form at very low temperatures (-160 degrees C). The all-trans chromophore of the bathoiodopsin produced from iodopsin in the presence of chloride thermally reverted to the 11-cis form, while in the presence of nitrate it kept its all-trans configuration upon warming. Different protein environments, either in a detergent or in phosphatidylcholine (PC) liposomes, did not change the reaction characteristics of the bathoiodopsins under the two anionic conditions. However, reaction characteristics of bathoiodopsins produced in the absence of small anions were dependent on the environment. The trans-to-cis isomerization occurred upon warming of bathoiodopsin in the presence of detergent but not in liposomes. Spectral measurements revealed that iodopsin in the absence of small anions is a mixture of two spectrally distinct forms that exhibit absorption maxima and reaction characteristics similar to those of chloride-bound and nitrate-bound iodopsins, respectively. Thus, iodopsin exhibits two conformational states, each of which is stabilized by the binding of chloride and nitrate, respectively.     

Investigation on light-addressable potentiometric sensor as a possible cell-semiconductor hybrid

This article reports an investigation on light-addressable potentiometric sensor (LAPS) to be used as a possible biological cell-semiconductor hybrid that will enable us to make an interface between the physical and biological system. To increase the surface potential sensitivity, we used a LAPS structure with single insulator (SiO2) coated with poly-L-ornithine and laminin (PLOL) on Si. Efficient culturing of PC-12 and nerve cells of Lymnaea stagnalis on PLOL-coated Si3N4 and SiO2 was achieved. The thickness of the PLOL layer was found to be about 4 nm by the atomic force microscope (AFM) measurement. Using the advantage of this thin layer of PLOL, we compared the performance of a novel structure to the previously reported "PLOL-coated Si3N4/SiO2/Si" structure. Due to high insulating capacitance, the photocurrent response of the novel LAPS was found to be very steep. As a result, higher sensitivity was achieved. This steepness did not degrade during 10 days when the sensor surface was kept in contact with the cell culture medium and environment. The thickness of PLOL layer, its ability to improve the biological cell adhesion, enhanced sensitivity, and experiment with simulated neural action potential (AP) applied to the novel LAPS show a good promise for LAPS to be a biological cell-semiconductor hybrid.     

The rates of deceleration of nuclear and organellar DNA syntheses differ in the progenitor cells of the apical meristems during carrot somatic embryogenesis

 The synthesis of DNA in nuclei and organellar nucleoids at the various stages of somatic embryogenesis in carrot (Daucus carota L. cv. Kurodagosun) was analyzed using anti-5-bromo-2′-deoxyuridine (BrdU) immunofluorescence microscopy. The active syntheses of both nuclear and organellar DNA started in the cells forming the embryo proper 3 d after the initiation of embryogenesis, but not in cells forming suspensor-like cell aggregates. In the early globular embryo, active DNA syntheses were continuously observed in the whole embryo proper, except for the progenitor cells of the root apical meristem (RAM) and shoot apical meristem (SAM). These were recognized as slowly cycling cells with a non-BrdU-labelled nucleus and strongly BrdU-labelled organellar nucleoids. At the heart- and torpedo-shaped embryo stages, both nuclear and organellar DNA syntheses were inactive in the presumptive RAM and SAM. Thus, slowing down of organellar DNA synthesis is not coupled with, but is later than, that of nuclear DNA synthesis in the progenitor cells of the embryonic RAM and SAM. These findings clearly indicate that the timing of DNA synthesis is similar in the progenitor cells of both the RAM and SAM in the early stages of somatic embryogenesis. Received: 18 January 2000 / Accepted: 2 March 2000     

Synthesis of adiposin-1 and related compounds

The synthesis is described of adiposin-1 (2a), isolated from an α-d-glucosidase inhibitor complex, adiposin, produced by Streptomyces caluvs TM-521. The synthesis involved the coupling of 1,6-anhydro-4-O-(3,4-anhydro-α-d-galactopyranosyl)-β-d-glucopyranose (13) with the di-O-isopropylidene derivative (7) of dl-(1,4,$\text{6}\text{5}$)-4,5,6-trihydroxy-3-(hydroxymethyl)-2-cyclohexenylamine. All possible diastereoisomers of the secondary amine were isolated by chromatography on silica gel. Their structures were tentatively assigned on the basis of ¹H-n.m.r. spectroscopy and optical rotation. Likewise, both the core-structure (4) of adiposin and the saturated analog (22) of 2a were synthesized.     

Surface plasmon field-enhanced fluorescence spectroscopy apparatus with a convergent optical system for point-of-care testing

Surface plasmon field-enhanced fluorescence spectroscopy (SPFS) is a promising methodology for point-of-care (POC) testing. The SPFS devices that have been reported are equipped with an angle rotating stage to adjust the surface plasmon resonance (SPR) angle. In a clinical setting, however, the SPR angle determination is a tedious and time-consuming process. In this study, we employed an SPFS instrument with a convergent optical system that allows the omission of this procedure. We demonstrated that this instrumentation allowed the sensitive determination of low concentrations of α-fetoprotein in serum and reduced the variation effect caused by the protein concentrations in samples. The SPFS with a convergent optical system is suitable for POC testing.