Wild chimpanzees deprived a leopard of its kill: Implications for the origin of hominin confrontational scavenging.

This study reports the first observed case of wild chimpanzees (Pan troglodytes) obtaining animal prey freshly killed by a sympatric leopard (Panthera pardus) and scavenging it with the leopard still nearby. This observation has important implications for the emergence of confrontational scavenging, which may have played a significant role in human evolution. Many scholars agree that eating meat became important during human evolution, and hominins first obtained meat by scavenging.

Organic anion transporters, OAT1 and OAT3, are crucial biopterin transporters involved in bodily distribution of tetrahydrobiopterin and exclusion of its excess.

Tetrahydrobiopterin (BH) is a common coenzyme of phenylalanine-, tyrosine-, and tryptophan hydroxylases, alkylglycerol monooxygenase, and NO synthases (NOS). Synthetic BH is used medicinally for BH-responsive phenylketonuria and inherited BH deficiency. BH supplementation has also drawn attention as a therapy for various NOS-related cardio-vascular diseases, but its use has met with limited success in decreasing BH, the oxidized form of BH.

Influence of 3'-azido-2',3'-dideoxyguanosine treatment on telomere length in human telomerase-immortalized human fibroblast cells.

In order to study telomerase activation in normal cells, a telomerase-immortalized fibroblast cell line, hTERT-BJ1, treated with a telomerase inhibitor, 3'-azido-2',3'-dideoxyguanosine (AZddG), is considered to be a good model. Long-term treatment with AZddG resulted in telomere shortening from 10-20 kbp to 5-6 kbp in cultured hTERT BJ1 cells. However, the telomere length then stabilized.

Synthesis of modified double stranded RNAs containing duplex regions between amide-linked RNA and RNA at both ends and enhanced nuclease resistance.

Synthetic short-interfering RNA (siRNA) has been a powerful tool to control gene expression. Chemical modification of the 3'-overhang regions of siRNA with amide-linked RNAs improved the exonuclease resistance and was compatible with RNAi function in cultured cells. To improve endonuclease resistance of the siRNA having amide-linked RNA modification at the 3'-terminal regions, we designed and synthesized new modified double stranded RNAs (dsRNAs) the 3'-terminal regions of which were modified with amide-linked RNA moieties and formed duplex structures with the complementary unmodified RNA moieties.

Case study of a one-sided attack by multiple troop members on a nontroop adolescent male and the death of Japanese macaques (Macaca fuscata).

An adolescent wild male Japanese macaque (Macaca fuscata), following Kinkazan A troop, was attacked one-sidedly by multiple members of the troop. The victim was identified as PI, and was estimated to be seven+/-one year old. The aggressive interaction was recorded by video camera until the end.

Time-dependent changes in cardiovascular function during copulation in male rats.

Purpose: Sudden cardiac death after ejaculation has been reported in humans and highlights the important relationship between sexual behavior and the heart. The rat is an extremely useful animal model for investigating reproductive function in male mammals. In this study, we examined the relationship between autonomic nervous system activity and the circulatory system during sexual behavior in male rats.

Tetrahydrobiopterin in intestinal lumen: its absorption and secretion in the small intestine and the elimination in the large intestine.

In treating hereditary deficiency of tetrahydrobiopterin (BH(4)), supplementation with BH(4) might be the ultimate choice of therapy. Oral administration of BH(4) has been believed to be inefficient owing to poor absorption of BH(4) in the intestine. In this study, we found a considerable amount of BH(4) as well as its oxidized pterins in the ingredients of intestinal lumen of mice when they were served food that did not contain significant amounts of biopterin.

Transcellular relocation of tetrahydrobiopterin across Caco-2 cells: a model study of tetrahydrobiopterin absorption through epithelial cells of intestinal mucosa.

Oral administration of tetrahydrobiopterin (BH(4)) has been known to be effective in treating BH(4)-deficient patients. It has long been established that BH(4) is absorbed by the intestinal mucosa. However, the mechanism for translocation of BH(4) across epithelial cells has not been elucidated.

Influence of 3'-azido-2',3'-dideoxyguanosine treatment on amounts of TERT and POT1 in human HL60 cells.

In human cells, TERT (telomerase reverse transcriptase) is involved in the synthesis of telomere DNA, and POT1 (protection of telomeres 1) is believed to be a regulator of telomere length. We have reported that long-term treatment of human HL60 cells with 50 microM 3'-azido-2',3'-dideoxyguanosine (AZddG) caused telomeres to shorten significantly during early passages (up to 40-50 days), but that telomere length was then stabilized at approximately 2 kbp during later passages. Additionally, cell growth rates showed no obvious change during culture in the presence of 50 microM AZddG.

Cellular uptake of sepiapterin and push-pull accumulation of tetrahydrobiopterin.

Cellular uptake of sepiapterin resulted in an efficient accumulation of tetrahydrobiopterin. Tetrahydrobiopterin is much less permeable across the cell membrane than sepiapterin or dihydrobiopterin, the precursors of the tetrahydrobiopterin-salvage pathway. The uptake of sepiapterin by the cell was examined under metabolic arrest with N-acetylserotonin, an inhibitor of sepiapterin reductase.

Role of a serotonin precursor in development of gut microvilli.

Monoamines exert diverse functions in various cells in peripheral organs as well as in the central nervous system. 5-Hydroxy-l-tryptophan (5-HTP) has been simply regarded as a precursor of serotonin, and it is believed that the biological significance of 5-HTP is essentially ascribable to the production of serotonin. Systemic treatment with 5-HTP is often applied to patients with low serotonin levels in the brain.

Solid-phase synthesis of modified RNAs containing amide-linked oligoribonucleosides at their 3'-end and their application to siRNA.

siRNAs against luciferase mRNA were modified with amide-linked oligoribonucleosides (amide-linked RNA) at their 3 '-overhangs. Tm values of the modified siRNAs increased compared with that of the unmodified siRNA. These results indicate that the modified overhangs increase the thermodynamic stability of the siRNAs.

Telomere shortening in human HL60 cells by treatment with 3'-azido-2',3'-dideoxynucleosides and telomerase inhibition by their 5'-triphosphates.

Telomerase is thought to play an important role in the mechanism of tumor cell immortalization by maintenance of telomere length. To obtain information on the susceptibility of telomerase to nucleoside analogues, the effects of base-modified 3'-azido-2',3'-dideoxynucleoside triphosphates on the enzyme were investigated. It is suggested that the 2-amino group of the nucleotide purine nucleus is important for the inhibitory activity.

Influence of nucleoside analogue treatment on telomere length and TRF2 amount in human HL60 cells.

Long-term treatment with 3'-azido-2',3'-dideoxy-guanosine (AZddG) results in reproducible telomere shortening in cultured human HL60 cells. TRF2 protein has been implicated in the protection of chromosome ends. It binds to double-strand repeats and may have an indirect role in protecting the G-rich overhang by recruiting other telomere-binding proteins to the G-tail or by mediating the formation of the telomeric t-loop.

Synthesis of a guanosine phosphoramidite derivative containing a photocleavable protecting group at the O6 position via regioselective protection of the 2'-hydroxy group with a TBDMS group.

To construct modified RNA that form A-type duplex with photo-irradiation, a photocleavable a-methyl-2-nitropiperonyl (MeNP) group was introduced at O(6) position of guanosine. A guanosine phosphoramidite derivative containing the MeNP group was synthesized via regioselective 2'-O-protection of 3',5'-O-di(t-butyl)silanediylguanosine with TBDMS group. The MeNP group was found to be stable under conditions of solid-phase synthesis of RNA.

3'-Azido-2',3'-dideoxynucleoside 5'-triphosphates inhibit telomerase activity in vitro, and the corresponding nucleosides cause telomere shortening in human HL60 cells.

Telomerase adds telomeric DNA repeats to the ends of linear chromosomal DNA. 3'-Azido-3'-deoxythymidine 5'-triphosphate (AZTTP) is a known telomerase inhibitor. To obtain more selective and potent inhibitors that can be employed as tools for studying telomerase, we investigated the telomerase-inhibitory effects of purine nucleosides bearing a 3'-down azido group: 3'-azido-2',3'-dideoxyguanosine (AZddG) 5'-triphosphate (AZddGTP), 3'-azido-2',3'-dideoxy-6-thioguanosine (AZddSG) 5'-triphosphate (AZddSGTP), 3'-azido-2',3'-dideoxyadenosine (AZddA) 5'-triphosphate (AZddATP) and 3'-azido-2',3'-dideoxy-2-aminoadenosine (AZddAA) 5'-triphosphate (AZddAATP).

The free-radical scavenger edaravone restores the differentiation of human neural precursor cells after radiation-induced oxidative stress.

Recently, it has been elucidated that cognitive dysfunction following cranial radiotherapy might be linked to the oxidative stress-induced impairment of hippocampal neurogenesis that is mediated by proliferating neural stem or progenitor cells. The novel free-radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been clinically used to reduce neuronal damage following ischemic stroke. Here, we demonstrate via in vitro studies that edaravone protects human neural stem cells (NSCs) from cell death and restores their differentiation ability after irradiation; however, the protective effect of edaravone is not observed in human brain tumor cells.

Telomerase inhibition by 3'-azido-2', 3'-dideoxynucleoside 5'-triphosphates and telomere shortening in human cultured cells by the corresponding nucleosides.

Telomerase is believed to be a good target for the development of antitumor agents. In this study, 3'-azido-2',3'-dideoxy-2-aminoadenosine (AZddAA), 3'-azido-2',3'-dideoxyadenosine (AZddA), 9-(3-azido-2,3-dideoxy-beta-D-ribofuranosyl)-2-aminopurine (AZddAP), 3'-azido-2-chloro-2',3'-dideoxyadenosine (AZddClA) and their triphosphate derivatives were synthesized. Telomerase assay studies showed that the 2-amino group plays an important role in the inhibitory activity of these compounds.

Synthesis and properties of modified siRNA having amide-linked oligoribonucleosides at their 3' overhang regions.

siRNAs against luciferase gene were modified with amide-linked oligoribonucleosides (amide-linked RNA) at their 3'-overhang regions. The modified siRNAs were more stable than the unmodified siRNA against degradation by nuclease S1, which indicates that the modified overhang regions increase the nuclease resistance of the siRNAs. Tm values of the modified siRNAs increased compared with that of the unmodified siRNA.

Influence of long-term treatment with cytosine arabinoside on telomere length in human HL60 cells.

Immortal tumor cells employ a telomere length maintenance mechanism to escape the normal limits on proliferation. We investigated whether treatment with cytosine arabinoside (AraC), whose triphosphate derivative AraCTP might partially inhibit the synthesis of C-rich telomere strands, is effective for inducing telomere shortening in human HL60 cells. Long-term treatment with 0.

Synthesis of antisense oligonucleotides containing a photocleavable protecting group on a guanine base and their photoinduced duplex formation.

An oligonucleotide containing a photocleavable protecting group at a guanine base was synthesized to induce the duplex formation by photo-irradiation. Alpha-methyl-2-nitropiperonyl (MeNP) group was used for the photocleavable protecting group at O6 position of deoxyguanosine. The oligonucleotide containing MeNP group (MeNP-ODN:5'-dTTCTG(MeNP)TCTGT-3') was synthesized by phosphoramidite method.

Telomere shortening in human HL60 cells by treatment with deoxyguanosine analogs.

Telomerase is a cellular endogenous reverse transcriptase thought to play an important role in the maintenance of telomere length. We investigated the effects of 3'-azido-2',3'-dideoxyguanosine (AZddG) and carbocyclic oxetanocin G (C.OXT-G), of which the triphosphate derivatives AZddGTP and C.

Chemo-enzymatic production of fuel ethanol from cellulosic materials utilizing yeast expressing beta-glucosidases.

Ethanol was produced in a considerably high yield by fermenting hydrolyzates from cellulosic materials by means of a recombinant laboratory yeast expressing beta-glucosidases. Tissue paper, cotton, and sawdust were hydrolyzed by two-step sulfuric acid hydrolysis to give mixtures containing glucose, cellobiose, and higher cello-oligosaccharides. After the cellulosic material was partially hydrolyzed with 80% sulfuric acid, the hydrolysis was continued with 5% sulfuric acid.