Induction of angiogenesis in chick yolk-sac membrane by polyamines and its inhibition by tissue inhibitors of metalloproteinases (TIMP and TIMP-2).

Treatment of yolk-sac membranes of 4-day-old chick embryos with spermine or spermidine resulted in angiogenesis in the membranes. The angiogenic activity of spermine was stronger than that of spermidine. Putrescine, polylysine and histamine did not induce angiogenesis in the membranes. Administration of putrescine, spermidine and spermine increased their respective levels in yolk-sac membranes, but no interconversion of these amines was observed. The increases in spermidine and spermine levels in yolk-sac membranes preceded induction of angiogenesis. The angiogenesis induced by spermine was inhibited by tissue inhibitors of metalloproteinases, that is, TIMP and TIMP-2. These findings suggest that spermine and spermidine are angiogenesis factors in yolk-sac membranes of chick embryos and that matrix metalloproteinases represented by collagenase are involved in their action.     

An anchorage-dependent locus in the cell cycle for the growth of 3T3 cells

Mouse fibroblasts, 3T3 cells, require a solid surface for continuous growth, but when 3T3 cells, during their exponential phase in Petri dishes, were transferred to a suspension culture, the number of cells roughly doubled by 30 h. During the suspension culture the number of pairing cells (c₂) increased, but that of the single cells decreased. When cells synchronized at mitosis or at the G1-S boundary were transferred to the suspension culture, the number of pairing cells peaked at 30 min and at 10 h, respectively. DNA synthesis began immediately after the cells, which were cultured for 16 h in the suspension, had settled onto the surface of the Petri dishes. When cells in a confluent culture were arrested at an early G1 period and were suspended, the number of pairing cells did not increase. These results indicate that the most important locus for anchorage growth seems to be at a late G1 period of the cell cycle.     

Expression of an mNSC1 in mammalian cells.

We have cloned a cDNA inducing a cation-permeable current (mNSC1) from pancreatic beta-cells, which shows niflumate-sensitive current in Xenopus oocytes. To elucidate the expression in mammalian cells, mNSC1 was expressed in CHO cells. The reversal potential by mNSC1 was shifted toward positive which was significantly reversed by flufenamic acid. Single-channel analysis showed a characteristic of a Ca-activated nonselective cation channel. Therefore, we may conclude that mNSC1 expresses a fenamates-sensitive cation channel, inducing membrane depolarization in a mammalian cell.     

Transformation of cucumber (Cucumis sativus L.) plants using Agrobacterium tumefaciens and regeneration from hypocotyl explants

Summary Transgenic cucumber (Cucumis sativus L.) plants were successfully obtained from hypocotyl explants inoculated with Agrobacterium tumefaciens, which harbored a binary vector plasmid with NOS-nptII, CaMV 35S-I-gus and CaMV 35S-hph genes. Acetosyringone enhanced the efficiency of transformation at the cut surface cells of hypocotyl explants during five days of co-cultivation. Transformed cells were more effectively selected using 20–30 mg/l hygromycin B than using 50–100 mg/l kanamycin. Shoot regeneration occurred within 4–6 wks, and 12 of 21 regenerated plantlets displayed strong GUS expression in the very young leaves. All of 8 GUS-positive R0 plants examined showed single or a few positive bands by Southern blot analysis. The expression of the CaMV 35S-I-gus gene was observed in various tissues and organs of R0 and R1 transgenic cucumber plants.     

Py-GC/MS analysis of sediments from Lake Biwa,Japan: characterization and sources of humic acids

Humic substances extracted and purified from bottom sediments of northern Lake Biwa, Japan, in November 2012 and 2013 were characterized using elemental analysis, Fourier-transform infrared spectroscopy, hydrogen-1 nuclear magnetic resonance (¹H NMR) analysis, and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). The infrared (IR) bands in the spectra of humic acids showed the presence of amide linkages and polysaccharides. Results of ¹H NMR analysis showed that the humic acids contained approximately twice the number of aliphatic protons as those in the Japanese soil standards used for comparison. Results of the Py-GC/MS analysis, which evaluates pyrolysis temperature dependency of the amount of pyrolysis products, showed that the generation of pyrolysis products in humic acids also differed from that in Japanese soil standards but was similar to that of phytoplankton in Lake Biwa. This analysis method is the first to provide extensive information about the chemical structure of humic substances; conventional Py-GC/MS provides limited information for a single temperature. Data suggest that humic acids in lake sediments are related to chemical characteristics of phytoplankton. Results shed new light on the origins of humic substances in deep-water-lake sediments and provide insights into material recycling in such sediments.     

Identification of a gene, Desiccate, contributing to desiccation resistance in Drosophila melanogaster

Suitable alterations in gene expression are believed to allow animals to survive drastic changes in environmental conditions. Drosophila melanogaster larvae cease eating and exit moist food to search for dry pupation sites after the foraging stage in what is known as the wandering stage. Although the behavioral change from foraging to wandering causes desiccation stress, the mechanism by which Drosophila larvae protect themselves from desiccation remains obscure. Here, we identified a gene, CG14686 (designated as Desiccate (Desi)), whose expression was elevated during the wandering stage. The Desi expression level was reversibly decreased by transferring wandering larvae to wet conditions and increased again by transferring them to dry conditions. Elevation of Desi expression was also observed in foraging larvae when they were placed in dry conditions. Desi encoded a 261-amino acid single-pass transmembrane protein with notable motifs, such as SH2 and PDZ domain-binding motifs and a cAMP-dependent protein kinase phosphorylation motif, in the cytoplasmic region, and its expression was observed mainly in the epidermal cells of the larval integuments. Overexpression of Desi slightly increased the larval resistance to desiccation stress during the second instar. Furthermore, Desi RNAi larvae lost more weight under dry conditions, and subsequently, their mortalities significantly increased compared with control larvae. Under dry conditions, consumption of carbohydrate was much higher in Desi RNAi larvae than control larvae. Based on these results, it is reasonable to conclude that Desi contributes to the resistance of Drosophila larvae to desiccation stress.     

Correction to: Comparative analysis of sperm motility in liquid and seminal coagulum portions between Bornean orangutan (Pongo pygmaeus) and chimpanzee (Pan troglodytes)

Primates - In the original publication of the article, the coauthor “Takashi Hayakawa” was wrongly assigned as co-corresponding author.