The human cytosolic molecular chaperones hsp90, hsp70 (hsc70) and hdj-1 have distinct roles in recognition of a non-native protein and protein refolding.

The properties of molecular chaperones in protein-assisted refolding were examined in vitro using recombinant human cytosolic chaperones hsp90, hsc70, hsp70 and hdj-1, and unfolded beta-galactosidase as the substrate. In the presence of hsp70 (hsc70), hdj-1 and either ATP or ADP, denatured beta-galactosidase refolds and forms enzymatically active tetramers. Interactions between hsp90 and non-native beta-galactosidase neither lead to refolding nor stimulate hsp70- and hdj-1-dependent refolding. However, hsp90 in the absence of nucleotide can maintain the non-native substrate in a 'folding-competent' state which, upon addition of hsp70, hdj-1 and nucleotide, leads to refolding. The refolding activity of hsp70 and hdj-1 is effective across a broad range of temperatures from 22 degrees C to 41 degrees C, yet at extremely low (4 degrees C) or high (>41 degrees C) temperatures refolding activity is reversibly inhibited. These results reveal two distinct features of chaperone activity in which a non-native substrate can be either maintained in a stable folding-competent state or refolded directly to the native state; first, that the refolding activity itself is temperature sensitive and second, that hsp90, hsp70 (hsc70) and hdj-1 each have distinct roles in these processes.     

Establishment processes and regeneration patterns of montane virgin coniferous forest in northeastern China

Abstract. The co-occurrence of Larix olgensis var. changpaiensis, Picea jezoensis and Abies nephrolepis in the coniferous forest of Mount Changbai, northeastern China, is discussed, and the regeneration pattern of these taxa compared on the basis of the analysis of the age structure and the age-height relationship of the three conifers. The presence of tall individuals (ca. 30 m in height) of Larix olgensis var. changpaiensis, which does not show any regeneration, was related to the large eruption of Mount Changbai up to ca. 400 yr ago. Picea jezoensis compensates its small recruitment by a large stem size and long life span together with a continuous height growth. Abies nephrolepis recruits well, but its small stem size and short life span do not result in its dominance in the forest.     

Nucleotide Sequence Surrounding the Locus Marker D21S246 on Human Chromosome 21

Most ofthe human Not I linking clones identified to date areconsidered to be derived from CpG islands because ofthe recognitionsequence of this enzyme, and CpG islands have been reportedto be located around the 5' regions of genes. As a pilot study,we determined the complete nucleotide sequence (41,924 bp) ofa human cosmid clone (LL21NC02Q7A10) containing the marker D21S246originating from a Not I linking clone. As a result of sequenceanalysis, we successfully mapped and revealed the genomic genestructure for KIAA0002 previously reported as a cDNA clone.This gene consists of 15 exons and was shown to exist at theD21S246 locus on human chromosome 21q21.3–q22.1. Theseresults demonstrated that genomic marker-anchored DNA sequencingis a useful approach for the human genome project.     

Expression of Regeneration-Associated Antigens in Normal and Retinoid-Treated Regenerating Limbs of Ambystoma mexicanum

The expression of two regeneration-associated antigens in the blastemas of normal and retinoid-treated regenerating limbs of axolotl ( Ambystoma mexicanum ) was examined.
One antigen, 55C12, which was similar to tenascin in expression pattern and molecular weight profile, was weakly expressed in the perichondrium and tendon of normal limbs. In the regenerating limbs, the amount of 55C12 antigen increased near the amputation site within 7 days and almost all cells of the blastema mesenchyme came to be positive to the antigen at 20 days, although those of epidermis and most stump tissues were negative. When the regenerating limbs were treated with Am80, a synthetic retinoid, which induced proximo-distal duplication, the expression of 55C12 antigen in the blastema became weak temporarily and was reactivated in the anterior region of the blastema. This expression pattern suggests that the duplicated limb is formed by the preferential growth of this 55C12-positive anterior blastema region.
The other antigen, 117C1, was faintly expressed in the epidermis, dermis, muscle, perichondrium and cartilage of normal limbs, and intensely expressed in the blastema mesenchyme and wound epidermis. The Am80 treatment, however, induced no changes in the expression pattern of 117C1.
These results suggest that these antigens may distinguish two different regions of the blastema in normal regeneration and retinoid-induced duplication.     

Efficiency of serum copper/zinc ratio for differential diagnosis of patients with and without lung cancer

We examined serum copper (Cu), serum zinc (Zn), and the serum copper/zinc ratio (Cu/Zn) in 162 patients. All of them were seen to have an abnormal shadow in the chest X-ray films, that is, 109 patients with lung cancer (LC) and 53 patients with no lung cancer (NLC). The mean Cu and Cu/Zn in LC patients were significantly higher than those in NLC patients (p<0.05). In LC patients, Cu and Cu/Zn were higher and Zn was lower in advanced tumors than early ones. There was a significantly clear relation between Cu or Cu/Zn and the tumor (T) stages. When the relative risk (RR) of LC was estimated, it was seen that the higher Cu and Cu/Zn became, the higher RR became. Furthermore, we showed the sensitivity of the receiver operator characteristic of the test (ROC) curve for Cu, Cu/Zn, and carcinoembryonic antigen (CEA) to diagnose LC, as explained in a paragraph of methods.The determinations of Cu, Zn, and Cu/Zn are simple and inexpensive. They also appear to have a great diagnostic value in determining the local invasion of LC and as a screening test in the high-risk patients for LC.     

Flower-Inducing Activity of Exogenous Lysine in Lemna paucicostata 151 Cultured on Nitrogen-Rich Medium

Flower-inducing activity of lysine was examined in Lemna paucicostata151, a weakly responsive short-day plant, cultured on nitrogen-richmedium under long-day conditions (continuous light). Lemna paucicostata151 was homogenized in a solution of lysine and the homogenatewas centrifuged. The supernatant (lysine-containing extract)was added to nitrogen-rich medium after passage through a membranefilter to give various concentrations of lysine in the medium.Flowering was induced in plants grown for six days on mediumthat contained lysine at concentrations above 0.25 µM.In plants grown on medium that contained 1 µM lysine,a significant flowering response was observed on the fourthday of culture. However, the flower-inducing activity of lysinedisappeared when the lysine-containing extract was added tothe medium and the medium was then autoclaved, suggesting thatthe active principle is unstable to autoclaving. Among derivativesof lysine tested, lysine hydroxamate had the highest flower-inducingactivity and lysyl lysine had almost same activity as that oflysine. When added to the medium without homogenization withplant material, lysine and lysyl lysine had flower-inducingactivity but lysine hydroxamate did not induce flowering. (Received April 26, 1993; Accepted November 8, 1993)     

Pyridoxal kinase immunoreactivity in rabbit brain

Murine polyclonal antibody against purified bovine brain pyridoxal kinase (EC 2.7.1.35) was generated and showed cross-reactivity with rabbit brain pyridoxal kinase. This antibody was used to immunohistochemically examine the distribution of pyridoxal kinase in the rabbit brain. The cytoplasm of neuronal cells and neuroglial cells in the cerebral cortex, hippocampal region, brain nuclei and cerebellar cortex showed positive staining with various degrees of intensity. The neuronal cells and surrounding fibers in some brain nuclei, such as the area tegmentalis ventralis or the substantia nigra, showed intense staining. The neuronal cells of the hippocampal region showed somewhat weak reactivity, but some with intense reactivity were found sparsely distributed and positive staining fiber networks of a very low density were also observed.     

Prevalence of Human Herpesvirus 6 Variants A and B in Patients with Chronic Fatigue Syndrome

Peripheral blood mononuclear cells collected from 13 patients with chronic fatigue syndrome and 13 healthy controls were analyzed for the presence of human herpesvirus 6 (HHV-6) DNA by variant-specific polymerase chain reaction and dot blot hybridization. HHV-6 DNA was detected in 7 of 13 (53%) patients, and of those 7 patients, 4 were positive for HHV-6 variant A DNA and 3 were for variant B. No HHV-6 DNA was detected in the controls. Serum antibody titers to the late antigen and antibody prevalence to the early antigen of HHV-6 were significantly higher in the patient group. These results suggest active replication of HHV-6 in patients with chronic fatigue syndrome.