Characteristics of settling matter and its role in nutrient cycles in a deep oligotrophic lake

The settling flux of seston (dry weight, DW), chlorophyll a (Chl a), particulate organic carbon (POC), particulate organic nitrogen (PON), and particulate phosphorus (PP) was measured monthly in 1981–1983 at 10 different depths in Lake Chuzenji, Japan; an oligotrophic lake with a maximum depth of 163 m. The Ti concentration in entrapped matter was used to separate the sedimentation flux into allochthonous and autochthonous components. Inflow loads of dissolved nutrients (DN: 4.5, DP: 0.48 g m^-2a^-1) were almost sufficient to supply the autochthonous fluxes at 30 m (PON: 2.9, PP: 0.51 g m^-2a^-1 ), and this flux of POC (26.6 g m^-2a ^-1) was about one-third of primary production (84 g C M^-2a^-1). Sedimentation of particulate matter was the main path of losing nutrients from lake water, explaining more than 80% removal of inflow loads (TN, TP). Decomposition rates during sedimentation which were calculated from the vertical difference in the autochthonous flux agreed very closely with the results obtained by laboratory experiments of a 100-day incubation (content ratios from field observations were: POC 0.67, PON 0.65, PP 0.85; and from laboratory experiments they were: POC 0.68, PON 0.70, PP 0.94). These decomposition rates and those near the sediment interface were used to explain dissolved oxygen depletion and nitrate increase in the hypolimnion during stratification. The average sinking velocities were 1.82m d^-1 for seston and 1.16 m d^-1 for Chl a at 30m, they were influenced by Chl a content of seston.     

Biological activities caused by far-infrared radiation

Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4–16 m) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters.     

Cloning, nucleotide sequence, and expression of the HincII restriction-modification system.

Two genes, coding for the HincII from Haemophilus influenzae Rc restriction-modification system, were cloned and expressed in Escherichia coli RR1. Their DNA sequences were determined. The HincII methylase (M.HincII) gene was 1,506 base pairs (bp) long, corresponding to a protein of 502 amino acid residues (Mr = 55,330). The HincII endonuclease (R.HincII) gene was 774 bp long, corresponding to a protein of 258 amino acid residues (Mr = 28,490). The amino acid residues predicted from the R.HincII and the N-terminal amino acid sequence of the enzyme found by analysis were identical. These methylase and endonuclease genes overlapped by 1 bp on the H. influenzae Rc chromosomal DNA. The clone, named E. coli RR1-Hinc, overproduced R.HincII. The R.HincII activity of this clone was 1,000-fold that from H. influenzae Rc. The amino acid sequence of M.HincII was compared with the sequences of four other adenine-specific type II methylases. Important homology was found between tne M.HincII and these other methylases.     

Expression of several growth factors and their receptor genes in human colon carcinomas

We have examined the expression of mRNAs for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-α), EGF receptor (EGFR), PDGF-A chain (PDGFA), PDGF-B chain (PDGFB) and PDGF receptor (PDGFR) genes in seven human colorectal carcinoma cell lines and 18 human colorectal carcinomas. In surgically resected specimens of the 18 colorectal tumors, TGF-α, EGFR, PDGFA, PDGFB and PDGFR mRNAs were detected at various levels in 15 (83%), 9 (50%), 18 (100%), 8 (44%) and 12 (67%), respectively. They were also detected in normal tissues. Interestingly, EGF mRNA was detected in only five (28%) of the tumors, but not in normal mucosa. Expression of EGF was also confirmed immunohistochemically in tumor cells. Of the five tumors expressing EGF, four expressed EGFR mRNA and showed a tendency to invade veins and lymphatics. All the colorectal carcinoma cell lines expressed TGF-α mRNA, and five cell lines expressed EGFR mRNA simultaneously. Production of TGF-α protein by DLD-1 and CoLo320DM cells was confirmed by TGF-α specific monoclonal antibody binding assay. The spontaneous³H-thymidine uptake by DLD-1 was suppressed by an anti-TGF-α monoclonal antibody. PDGFA and PDGFB mRNA were also expressed in four cell lines, but PDGFR and EGF mRNA was not detected. These results suggest that human colorectal carcinomas express multi-loops of growth factors and that TGF-α produced by tumor cells functions as an autocrine growth factor in human colonic carcinoma.     

Allozyme diversity and the evolution ofCrepidiastrum (Compositae) on the Bonin (Ogasawara) Islands

The genusCrepidiastrum is distributed in East Asia and includes 7 species. In the Bonin Islands, three species ofCrepidiastrum occur, and all of them are endemic to the islands. For detecting the origin and speciation of these endemic species, electrophoretic studies have been done in three endemic species of the Bonin Islands as well as in the remaining four species ofCrepidiastrum, andYoungia denticulata which is considered to be closely related toCrepidiastrum. A total of 386 individuals were sampled from 14 populations. As a result, 17 loci of 10 enzyme systems were resolved and gene frequencies for each population were calculated. The genetic variability was low in island species, as reported in some oceanic island plants. Four groups were recognized in the dendrogram generated by the UPGMA method. The Bonin endemics were clustered together, suggesting a monophyletic origin.C. ameristophyllum andC. linguaefolium were found to be genetically very similar, and this may suggest recent and rapid speciation within the islands.     

Dendritic cell activating factor produced by mouse macrophage hybridoma

A mouse macrophage (M phi) hybridoma which produces a soluble factor responsible for the cooperation between M phi and spleen dendritic cells (DC) was constructed. The antigen-presenting activity and the stimulator cell activity in the allogeneic or syngeneic mixed leukocyte reaction of DC were significantly augmented when DC were incubated with the culture supernatant of the hybridoma treated with various stimulants including latex beads. The monokine present in the culture supernatant of the hybridoma, called dendritic cell-activating factor (DCAF), augmented the production of lymphocyte-activating factor by DC while Ia expression of DCAF-treated DC was not altered. DCAF had no effect on the antigen-presenting activity of peritoneal resident M phi or B cell blasts while the antigen-presenting activity of spleen M phi was enhanced, but the degree of the enhancement was much less than that of spleen DC. DCAF was found to have the following properties: its pI value is between pH 4 and 5; it is stable at pH 2 to 10; and it loses its activity on incubation at 75 C for 30 min. When the culture supernatant of the hybridoma stimulated with latex beads was subjected to gel filtration, the DCAF activity was detected in the 20 Kd to 25 Kd, 30 Kd to 40 Kd, and 50 Kd to 60 Kd molecular weight regions. The 30 Kd to 40 Kd fraction, which is the major peak fraction, was further purified by ion-exchange chromatography followed by gel-filtration chromatography. When each fraction was subjected to SDS-PAGE, a 30 Kd band corresponding to the DCAF activity was observed and DCAF was purified to about 90% purity.     

Construction of protocellular structures under simulated primitive earth conditions

We have developed experimental approaches for the construction of protocellular structures under simulated primitive earth conditions and studied their formation and characteristics. Three types of envelopes; protein envelopes, lipid envelopes, and lipid-protein envelopes are considered as candidates for protocellular structures. Simple protein envelopes and lipid envelopes are presumed to have originated at an early stage of chemical evolution, interaction mutually and then evolved into more complex envelopes composed of both lipids and proteins.Three kinds of protein envelopes were constructedin situ from amino acids under simulated primitive earth conditions such as a fresh water tide pool, a warm sea, and a submarine hydrothermal vent. One protein envelope was formed from a mixture of amino acid amides at 80 °C using multiple hydration-dehydration cycles. Marigranules, protein envelope structures, were produced from mixtures of glycine and acidic, basic and aromatic amino acids at 105 °C in a modified sea medium enriched with essential transition elements. Thermostable microspheres were also formed from a mixture of glycine, alanine, valine, and aspartic acid at 250 °C and above. The microspheres did not form at lower temperatures and consist of silicates and peptide-like polymers containing imide bonds and amino acid residues enriched in valine. Amphiphilic proteins with molecular weights of 2000 were necessary for the formation of the protein envelopes.Stable lipid envelopes were formed from different dialkyl phospholipids and fatty acids.Large, stable, lipid-protein envelopes were formed from egg lecithin and the solubilized marigranules. Polycations such as polylysine and polyhistidine, or basic proteins such as lysozyme and cytochromec also stabilized lipid-protein envelopes.     

Progression of the phenotype of transformed cells after growth stimulation of cells by a human papillomavirus type 16 gene function.

Alteration of the growth properties of the established murine fibroblast cell lines NIH 3T3 and 3Y1 was studied in monolayer cultures and in cells suspended in semisolid medium after introduction of a cloned human papillomavirus type 16 (HPV16) DNA. HPV 16 DNA stimulated both cell lines to grow beyond their saturation densities in monolayer cultures without any apparent morphological changes or tendency to pile up. These cells were also stimulated to grow in soft agar. Since essentially all the cells that received the viral gene were stimulated to grow, the growth-stimulatory activity of HPV16 appeared to be due to the direct effect of a viral gene function. The NIH 3T3 cells showed an additional change in growth properties upon prolonged incubation of dense monolayers of cells containing the HPV16 DNA; morphologically recognizable dense foci appeared at a frequency of about 10(-3). These cells, when cloned from the foci, grew more rapidly in soft agar than the parental cells and were morphologically transformed. In other words, there were two sequential steps in cell transformation induced by HPV16. Practically all the viral DNAs were present in the cells as large rearranged multimers and were integrated into host chromosomal DNA. There was no obvious difference in the state of viral DNA in the cells of the original clone or the three subclones derived from it as dense foci. There was no difference in the amount or the number of viral RNA species expressed in the cells at these two stages. The secondary changes in the growth properties of NIH 3T3 cells appear to be due to some cellular alterations.