In Vitro HIV-1 LTR Integration into T-Cell Activation Gene CD27 Segment and the Decoy Effect of Modified-Sequence DNA

Integration into the host genome is an essential step in the HIV-1 life cycle. However, the host genome sequence that is favored by HIV-1 during integration has never been documented. Here, we report that CD27, a T cell activation gene, includes a sequence that is a target for in vitro HIV-1 cDNA integration. This sequence has a high affinity for integrase, and the target nucleotides responsible for this higher affinity were identified using a crystal microbalance assay. In experiments involving a segment of the CD27 gene, integration converged in the target nucleotides and flanking sequence DNA, indicating that integration is probably dependent upon the secondary structure of the substrate DNA. Notably, decoy modified CD27 sequence DNAs in which the target nucleotides were replaced suppressed integration when accompanying the original CD27 sequence DNA. Our identified CD27 sequence DNA is useful for investigating the biochemistry of integrase and for in vitro assessment of integrase-binding inhibitors.     

Regional excitatory and inhibitory amino acid levels in epileptic El mouse brain

Inbred mutant El mice are highly susceptible to convulsive seizures upon tossing stimulation. The levels of excitatory (e.g. glutamate and aspartate) and inhibitory amino acids [e.g. -aminobutyrate (GABA)] were examined in discrete regions of stimulated El mice [El(+)] non-stimulated El mice [El(-)] and ddY mice, which do not have convulsive disposition. In comparison with ddY, a general increased levels of aspartate, glutamate, glutamine, and taurine were detected in brain regions of El(-). The levels of GABA and glycine were almost the same in ddY and El(-). Compared to El(+), the levels of aspartate, glutamate, glutamine, and GABA in El(-) were either the same or higher. In the case of taurine and glycine, the levels in El(-) were either the same or lower than El(+). Alanine is special in that El(-) have a higher level than El(+) in hippocampus but lower in cerebellum. Furthermore, while marked changes were registered in several brain regions, none of the amino acids investigated showed any significant differences in the hypothalamus of three different groups of mice.     

The WHI1+ gene of Saccharomyces cerevisiae tethers cell division to cell size and is a cyclin homolog.

WHI1-1 is a dominant mutation that reduces cell volume by allowing cells to commit to division at abnormally small sizes, shortening the G1 phase of the cell cycle. The gene was cloned, and dosage studies indicated that the normal gene activated commitment to division in a dose-dependent manner, and that the mutant gene had a hyperactive but qualitatively similar function. Mild over-expression of the mutant gene eliminated G1 phase, apparently entirely relaxing the normal G1 size control, but revealing hitherto cryptic controls. Sequence analysis showed that the hyperactivity of the mutant was caused by the loss of the C-terminal third of the wild-type protein. This portion of the protein contained PEST regions, which may be signals for protein degradation. The WHI1 protein had sequence similarity to clam cyclin A, to sea urchin cyclin and to Schizosaccharomyces pombe cdc13, a cyclin homolog. Since cyclins are inducers of mitosis, WHI1 may be a direct regulator of commitment to division. A probable accessory function of the WHI1 activator is to assist recovery from alpha factor arrest; WHI1-1 mutant cells could not be permanently arrested by pheromone, consistent with a hyperactivation of division.     

Studies on the ontogenesis and the regulatory mechanisms of placental lactogen and insulin binding sites (receptor) in rat liver

The ontogenesis of specific binding of 125I-hPL and 125I-insulin was determined in rat liver cell membranes (10(5) X g pellets), and the regulatory mechanisms of these binding sites were also examined. There were striking differences in the mode of ontogenesis between binding sites of hPL and insulin in rats. HPL binding sites were very few in liver cell membranes from fetal and immature rats. They began to increase after puberty, and markedly increased in late pregnancy. On the other hand, insulin binding sites, which decreased in late pregnancy, were dominant in fetal liver and placenta. Consequently, the lipolytic and glycogenolytic activities of hPL in maternal liver were accentuated, whereas the effects of insulin on maternal liver were suppressed. In contrast, in fetal liver and placenta only the anabolic effects of insulin seemed conspicuous. According to the results of experiments on in vivo administration of estradiol-17 beta, progesterone, hydrocortisone or hPL to intact or hypox-rats, and the measurement of serum rat chorionic mammotropin (rCM), rPRL, estradiol-17 beta, and insulin during pregnancy in rats, the increase in hepatic hPL binding sites observed in late pregnancy might be, at least in part, due to rCM secreted from placenta, and the decrease in insulin binding sites due to the increase in serum insulin itself in rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased choline acetyltransferase activity by Chinese herbal medicine Sho-saiko-to-go-keishi-ka-shakuyaku-to in aged rat brain

The effect of a Chinese herbal medicine Sho-saiko-to-go-keishi-ka-shakuyaku-to (TJ-960) on the brain choline acetyltransferase (CAT) activity was studied in adult (3.5 months of age) and aged (24 months of age) rats. After oral administration of 5% TJ-960 solution for 3 months, CAT activity in the hippocampus, pons-medulla oblongata and striatum of aged rats was significantly lower than that of adult rats. CAT activity in the cerebellum, however, was significantly higher in the aged rats, as compared to the adult rats. TJ-960 significantly increased CAT activity in the hippocampus and striatum of aged rats, but did not affect the activity of the enzyme in the adult rat brain.     

药用寄生植物菟丝子属,列当属和无根藤属氨基酸的分析

本文测定了菟丝子属、列当属和无根藤属某些种的种子和植株氨基酸的种类组成和含量。结果表明,3个属种子和植株氨基酸均在15种以上,且含量丰富,特别是必需氨基酸的含量较高。文中讨论了氨基酸的药用和在种子鉴定与化学分类上的作用,探讨了开发应用的前景。     

Accumulation of poly-(hydroxybutyrate) by a non-sulfur photosynthetic bacterium,Rhodobacter sphaeroides RV at different pH

Summary Effect of pH of culture media on intracellular accumulation of poly-(hydroxybutyrate) (PHB) by a non-sulfur photosynthetic bacterium, Rhodobacter sphaeroides strain RV was studied in pH-stat cultures. Sub-optimal pH for growth, 8.0 or 8.5 gave the higher content of PHB rather than optimal pH 7.5 for growth. These results show that growth and PHB accumulation of the bacteria can be controlled by pH of culture media.     

Thermophilic microbial degradation of polyethylene succinate

This paper examined the biodegradability of a new aliphatic polyester, polyethylene succinate (PES), at a high incubation temperature of 50°C. The distribution and population of total colonies and of PES degrading micro organisms on polymer-emulsified agar plates were determined using the plate count and clear zone methods. The PES-decomposers were present in six of 10 soil samples and the total number ranged from 2.0×104 to 2.2×106 c.f.u./g of samples. Degrading microorganisms constituted between 20 and 80% of the total colonies on PES–agar plates. A single PES-degrading strain, TT96, was isolated and tested for its biodegrading capacity on PES powder and on other aliphatic polyesters: poly(beta-hydroxybutyrate) (PHB), polycaprolactone (PCL), poly(butylene succinate) (PBS), and poly(L-lactide) (PLA). Degraded films of PES and PBS were presented and compared using scanning electron microscopy. Strain TT96 was able to create clear zones on all the polymers used, except on PHB-agar plates. Liquid culture test after 2 weeks showed that TT96 completely degraded PCL powder but had very little activity on other samples. Scanning electron micrograph confirmed the microbial attack of TT96 on PES and PBS films. PES film surfaces were degraded more uniformly compared to PBS films which were decomposed only in some parts.