Ce³+-induced exopolysaccharide production by Bradyrhizobium sp. MAFF211645

Ce³⁺, a rare earth element (REE), has been widely used in high-technology industries. Despite the importance of Ce³⁺ in the fields of chemistry and physics, the role of Ce³⁺ in biology has been ignored. To investigate physiological effects of Ce³⁺ on microorganisms, we screened microorganisms that showed peculiar growth in the presence of Ce³⁺. We isolated a free-living soil bacterium that produced exopolysaccharide (EPS) around its colonies on 1/100 nutrient agar with 30 μM CeCl₃ or 1.0% d-mannitol. The bacterium was identified as Bradyrhizobium sp. by morphological, biochemical, and physiological tests as well as 16S rDNA sequence analysis. La³⁺, Pr³⁺, and Nd³⁺ also induced EPS production in large quantities, while Sm³⁺ did in small amounts. However, other heavier REEs from Eu³⁺ to Lu³⁺, and metals such as Na⁺, Al³⁺, K⁺, Ca²⁺, V³⁺, Cr³⁺, Co²⁺, Ni²⁺, Sr²⁺, Ba²⁺, and Pb²⁺ did not induce EPS production. The mean molecular weight of EPS was estimated to be approximately 1 × 10⁶ by Sepharose CL-4B column chromatography. TLC revealed that EPS was composed of l-rhamnose. Quantitative analysis of alditol acetate derivatives of acid hydrolyzate of EPS by GLC revealed that EPS was composed of more than 95% l-rhamnose, indicating that this EPS was a rhamnan. The spectrum of FT-IR of the rhamnan demonstrated that l-rhamnose residues in the rhamnan were α-linked. GC/MS analysis of methylated alditol acetate derivatives of the rhamnan demonstrated that it was composed of main chain α-(1→4)-linked l-rhamnopyranosyl residues. From spectral analyses of ¹H-NMR and FT-IR, EPS produced in the presence of 1.0% d-mannitol was found to be structurally similar to rhamnans.     

Estrogen regulation of the insulin-like growth factor I gene transcription involves an AP-1 enhancer

As a step toward elucidating the physiological role of insulin-like growth factor-I (IGF-I) in mediating estrogen action, we sought to determine the molecular basis of the phenomenon. In HepG2 cells expressing exogenous estrogen receptors (ER), a reporter gene plasmid containing 600 base pairs of the chicken IGF-I promoter enhanced expression of luciferase 8.6-fold in response to 10(-6) M 17 beta-estradiol, indicating that the IGF-I promoter is a target of estrogen regulation. Although no conventional estrogen-responsive element was identified within the promoter fragment, the AP-1 motif located therein was shown to be essential; the estrogen-responsive enhancement of the Fos-Jun binding to the AP-1 motif, which takes place by means of post-translational modification, mediates the estrogen action. A direct or indirect interaction between the estrogen-ER complex and the Fos-Jun complex seems to facilitate the Fos-Jun binding to the target DNA. Although ER binding to the target DNA was not considered to be involved in the signaling pathway, the DNA binding domain-deficient ER did not mediate the phenomenon, providing support for the existence of a unique function of the DNA binding domain of ER in facilitating some protein-protein interaction. In conclusion, our present observations demonstrate that the chicken IGF-I gene promoter is controlled by estrogen through a unique pathway involving Fos, Jun, and the DNA binding domain of ER.     

Negative air ions created by water shearing improve erythrocyte deformability and aerobic metabolism

To elucidate a potential mechanism by which negative air ions improve aerobic metabolism, changes in venous blood lactate levels, pH, erythrocyte deformability, and plasma superoxide dismutase activity and ceruloplasmin levels were examined during a 1-h exposure to negative air ions created by water shearing or corona discharge in nine adult healthy volunteers. The blood lactate level decreased from 1.3 +/- 0.3 to 1.0 +/- 0.2 mmol/l, pH increased from 7.388 +/- 0.025 to 7.417 +/- 0.036, and erythrocyte deformability improved from 37.0 +/- 2.2 to 35.1 +/- 3.0 s, expressed as the mean +/- s.d., when exposed to negative air ions created by water shearing, but did not change when exposed to negative air ions created by corona discharge. Other variables did not change in either exposure. The results obtained suggest that negative air ions created by water shearing improve aerobic metabolism by improving erythrocyte deformability. PRACTICAL IMPLICATIONS: The paper shows that negative air ions created by water shearing method improve aerobic metabolism only during a 1-h exposure, which may be caused by improvement of erythrocyte deformability, but negative air ions created by corona discharge have no effects. A potential mechanism is that negative air ions enter the circulating blood via the lungs and electrons of these ions are delivered to the plasma protein. Why negative air ions created by corona discharge have no effects is considered that water binding does not exist so that the lifetime of these ions is markedly short, by which the ions cannot reach the alveoli of the lungs sufficiently.     

Increased heat shock protein expression after stress in Japanese quail

The health care received from first admission to a pediatric rheumatology clinic to 9-year follow-up was assessed in 109 patients with chronic inflammatory rheumatic diseases or chronic idiopathic musculoskeletal pain. Ninety-five of the patients had received hospital care after the first admission, of whom 53 patients > or = 18 years, 21 patients < 18 years, and 33 parents of patients < 18 years rated their degree of satisfaction with the health care from 0 to 10. Mean scores of satisfaction with different aspects of care ranged from 6.0 to 9.6. Among patients > or = 18 years, those with idiopathic pain were less satisfied than those with inflammatory rheumatic diseases on the availability of care (mean 6.4 vs. 8.5, p < 0.001), continuity of care (mean 6.5 vs. 8.4, p < 0.001), and empathy of the health care providers (mean 6.7 vs. 7.9, p <0.05). The diagnostic group and the occurrence of remission predicted the level of global satisfaction in patients > or = 18 years. In patients < 18 years, chronic family difficulties predicted patient satisfaction and physical disability and chronic family difficulties predicted parent satisfaction. In conclusion, most parents and patients with inflammatory rheumatic diseases were satisfied with the health care. However, some patients with idiopathic pain had unmet needs for care.     

Tooth pulp neurons in the caudal medulla oblongata of the cat

The medulla oblongata caudal to the obex was explored for neurons responsive to tooth pulp (TP) stimulation in cats. Four different subclasses of TP neurons were found. The latter included TP specific (TPS) neurons, trigeminal wide dynamic range (trigeminal WDR) neurons with TP input, trigeminal subnucleus reticularis ventralis (trigeminal SRV) neurons with TP input and convergent reticular formation (convergent RF) neurons with TP input. TPS neurons were located in the dorsal marginal rim of the trigeminal subnucleus caudalis, i.e., in the marginal layer or the outer zone of substantia gelatinosa. WDR neurons with TP input were found in the neck region of medullary dorsal horn which corresponds to the lateral part of subnucleus reticularis dorsalis (SRD). Trigeminal SRV neurons with TP input were located in the lateral part of SRV. Convergent RF neurons with TP input were found in the middle third of the caudal bulbar RF consisting of SRD and SRV. Both TPS neurons and WDR neurons with TP input included trigeminothalamic neurons as evidenced by the antidromic activation from the nucleus ventralis posteromedialis of the contralateral thalamus. A significant proportion of both trigeminal SRV and convergent RF neurons with TP input were antidromically activated by stimulation of the nucleus centralis lateralis of the contralateral thalamus. The former two subclasses may subserve the sensory-discriminative aspect of toothache, while the latter two subclasses, the emotional-motivational aspect.     

Epilepsy and exacerbation of brain injury in mice lacking the glutamate transporter GLT-1

Extracellular levels of the excitatory neurotransmitter glutamate in the nervous system are maintained by transporters that actively remove glutamate from the extracellular space. Homozygous mice deficient in GLT-1, a widely distributed astrocytic glutamate transporter, show lethal spontaneous seizures and increased susceptibility to acute cortical injury. These effects can be attributed to elevated levels of residual glutamate in the brains of these mice.     

A representation method of assembly tasks for dealing with uncertainty

This article proposes a representation method of assembly tasks that enables a robotic system to carry out the tasks under uncertainty. The assembly task is represented by the sequence of contact states and control parameters that are generated by repeated measurements of force sensor outputs with the guide of control sphere conditions. The article describes how the control sphere conditions guarantee the correct transitions of contact states between objects along the sequence of the contact states. Finally the article demonstrates the effectiveness of our representation method by experimental works. © 1998 John Wiley & Sons, Inc.