Myb类基因Ibmyb在甘薯不同品种中的表达

研究Ibmyb基因在不同甘薯品种中的表达情况。目前Soedarjo等已从甘薯紫色块根的cDNA文库中克隆出了一条全长1243bp的cDNA序列,经测序及同源性比较,推测该基因为花青苷Myb类转录因子基因,命名为Ibmyb。本研究根据Ibmyb基因cDNA序列设计了2对引物,分别对紫叶的‘#13’和紫色块根的‘Benihikari’的叶和块根进行了RT-PCR分析;以Ibmyb cDNA为探针对这两个品种进行了Southern杂交分析。结果表明该基因在这两个甘薯品种的叶和块根中都表达,在甘薯基因组中具有多个拷贝且品种间不存在限制性片段长度多态性。表明Ibmyb可能是一种在甘薯中普遍存在的蛋白。     

Very low vitamin C activity of orally administered L-dehydroascorbic acid.

The biological activity of L-dehydroascorbic acid (DHA), which is easily formed from L-ascorbic acid (ASC) during storage and cooking processes, has been considered to be equivalent to that of ASC on the basis of studies made several decades ago, when a specific method to determine ASC was not available. The nutritional activity of orally ingested DHA has now been evaluated by comparing ASC concentrations in 12 tissues of rats administered four different doses of ASC. Determinations were made by using the specific and sensitive method, which had been developed by us. Here it is shown that the efficiency of DHA was almost 10% of that of ASC on a molar basis, based on animal experiments using the inherently scorbutic ODS rat, which is a convenient human model animal to investigate the metabolism of vitamin C. On the basis of these findings, it is proposed that it is necessary to reevaluate the nutritional requirement of vitamin C based on both ASC and DHA contents of foods.     

Lateral hopping of molecules induced by excitation of internal vibration mode

We demonstrate electron-stimulated migration for carbon monoxide (CO) molecules adsorbed on the Pd(110) surface, which is initiated by the excitation of a high-frequency (HF) vibrational mode (C-O stretching mode) with inelastic tunneling electrons from the tip of scanning tunneling microscopy. The hopping phenomenon, however, cannot be detected for CO/Cu(110), even though the hopping barrier is lower than in the CO/Pd(110) case. A theoretical model, which is based on the anharmonic coupling between low-frequency modes (the hindered-translational mode related to the lateral hopping) and the HF mode combined with electron-hole pair excitation, can explain why the hopping of CO is observed on Pd(110) but not on Cu(110).     

Turning blood into brain: cells bearing neuronal antigens generated in vivo from bone marrow

Bone marrow stem cells give rise to a variety of hematopoietic lineages and repopulate the blood throughout adult life. We show that, in a strain of mice incapable of developing cells of the myeloid and lymphoid lineages, transplanted adult bone marrow cells migrated into the brain and differentiated into cells that expressed neuron-specific antigens. These findings raise the possibility that bone marrow-derived cells may provide an alternative source of neurons in patients with neurodegenerative diseases or central nervous system injury.     

Axle-less F1-ATPase rotates in the correct direction

F1-adenosine triphosphatase (ATPase) is an ATP-driven rotary molecular motor in which the central gamma subunit rotates inside a cylinder made of three alpha and three beta subunits alternately arranged. The rotor shaft, an antiparallel alpha-helical coiled coil of the amino and carboxyl termini of the gamma subunit, deeply penetrates the central cavity of the stator cylinder. We truncated the shaft step by step until the remaining rotor head would be outside the cavity and simply sat on the concave entrance of the stator orifice. All truncation mutants rotated in the correct direction, implying torque generation, although the average rotary speeds were low and short mutants exhibited moments of irregular motion. Neither a fixed pivot nor a rigid axle was needed for rotation of F1-ATPase.     

Biohybrid artificial pancreas: long-term implantation studies in diabetic, pancreatectomized dogs

Diabetic complications such as neuropathy, retinopathy, and renal and cardiovascular disease continue to pose major health risks for diabetic patients. Consequently, much effort has focused on approaches that could replace conventional insulin therapy and provide more precise regulation of blood glucose levels. The biohybrid perfused artificial pancreas was designed to incorporate islet tissue and a selectively permeable membrane that isolates this tissue from the immune system of the recipient. Biohybrid pancreas devices containing canine islet allografts were implanted in ten pancreatectomized dogs requiring 18 to 32 units of injected insulin daily. These implants resulted in good control of fasting glucose levels in six of these animals without further exogenous insulin for periods of up to 5 months.     

Reverse-phase liquid chromatographic determination of paraquat and diquat in agricultural products

A simple, rapid, highly sensitive liquid chromatographic method is described for the quantitative determination of paraquat and diquat residues in agricultural products. Paraquat and diquat are extracted with hot dilute hydrochloric acid and are cleaned up on an Amberlite CG-50 column, followed by reverse-phase liquid chromatography on an NH2 column, with ultraviolet detection at 257 nm (paraquat) and 310 nm (diquat). The minimum detectable concentration of both paraquat and diquat was 0.5 ng per injection, which corresponds to a lower detection limit of approximately 0.02 microgram/g in the original samples. Recoveries of paraquat and diquat added to various samples were greater than 79%, and averaged 91 and 90%, respectively, at the 0.1 and 1.0 microgram/g spiking levels.     

Protective effects of sugar cane extracts (SCE) on Eimeria tenella infection in chickens

The effects of oral administration of sugar cane extracts (SCE) on Eimeria tenella oocysts infection in chickens were studied with 2 different experiments. In Experiment 1, 3-week-old inbred chickens (MHC; H.B15) were inoculated into the crop with SCE (500 mg/kg/day) for 1 day or 3 consecutive days, and then challenged with E. tenella sporulated oocysts (2 x 10(4) cells/chicken). In Experiment 2, 1-week-old chickens were orally administered SCE at the same dose for 3 consecutive days, and then initially infected with E. tenella sporulated oocysts (2 x 10(3) cells/chicken). At 2 and 3 weeks of age, these chickens were immunized intravenously with the mixed antigens of sheep red blood cells (SRBC) and Brucella abortus (BA). At 4 weeks of age, chickens were challenged with E. tenella sporulated oocysts (1 x 10(5)/chicken). Challenged chickens with E. tenella oocysts showed markedly decreased body weight gain/day, severe hemorrhage and great number of shedding oocysts in feces and high lesion scores. Oral administration of SCE and initial infection with oocysts (2 x 10 (3)/chicken) resulted in a remarkable improvement in body weight gain/day, hemorrhage, the number of shedding oocysts and lesion score, compare to other infected groups. In addition, SCE-inoculated chickens with the initial infection showed a significant increase in antibody responses against SRBC and BA and also improvement in decreased relative proportions of Bu-1a(+) and CD4( )cells in cecal tonsil lymphocytes of E. tenella-challenged chickens. Cecal tissues of chickens administered SCE and initially infected with E. tenella oocysts showed lower numbers of schizonts, gametocytes and oocysts than those of infected control chickens. These results suggest that SCE have immunostimulating and protective effects against E. tenella infection in chickens.     

Effect of modified oligopeptides from the beetle Allomyrina dichotoma on Escherichia coli infection in mice

The novel peptides based on a putative active site of defensin, an anti-bacterial peptide from the beetle Allomyrina dichotoma, were synthesized. These synthetic oligopeptides exhibited strong anti-bacterial activity in vitro, even against antibiotic-resistant pathogenic bacteria. Then, anti-bacterial activity of two newly synthesized peptides, RLYLRIGRR-NH(2) (peptide A) and RLRLRIGRR-NH(2) (peptide B) was also examined by macroscopic and histopathologic assessment during the course of infection in mice inoculated with antibiotic-resistant pathogenic Escherichia coli (E. coli) in vivo. Peptide B decreased the mortality of mice inoculated with antibiotic-resistant pathogenic E. coli. The results of macroscopic and histopathologic examinations revealed that peptide B could protect the mice from infection. In contrast, peptide A failed to protect mice from infection with antibiotic-resistant pathogenic E. coli. Also, modified peptides A and B produced no toxicity or side effects in mice. These results suggest that peptide B is useful for developing novel antibiotics against antibiotic-resistant pathogenic bacteria.