茶刺蛾颗粒体病毒病毒粒子的表面增强拉曼散射(SERS)光谱研究

得到并分析了茶刺蛾颗粒体病毒(Darna trima Granulosis Virus缩写为DtGV)病毒粒子的SERS谱.DtGV病毒粒子通过COO(COOH)和NH_2(NH_3)基因被吸附到银溶胶表面上.Trp、Tyr和Phe残基侧链靠近银表面、以Trp残基侧链的振动增强效应最显著.上还增强特性与溶液的pH值密切相关.     

Surface-decontaminating action of glutaraldehyde in the gas-aerosol phase.

The surface disinfectant effect of glutaraldehyde in the gas-aerosol phase was investigated at different relative humidities and temperatures. At a gas-aerosol concentration of 15 to 20 mg/m3 and a relative humidity of about 80%, glutaraldehyde had a good disinfectant effect against both vegetative bacteria (decimal reduction time, less than 5 min) and bacterial spores (decimal reduction time, less than 45 min). In spite of its low volatility, glutaraldehyde was more effective than formaldehyde when the two substances were compared on an "added amount" basis.     

Nonsense and insertion mutants in the relA gene of E. coli: cloning relA.

We have made use of lysogens of a specialized transducing bacteriophage, lambdapyrG+ relA+, to select nonsense (relAnon) and insertion (relAins) mutations in the relA gene. Three independent relAnon mutants were isolated on the phage. In all three, the relaxed phenotype was suppressed by supD, supE, supF or sup6. Three independent relAins mutants were isolated, all containing an insertion element (probably IS2) in an apparently identical location in the relA gene. Polyacrylamide gel electrophoretic analysis of peptides synthesized by the phages in ultraviolet lightkilled host cells revealed that no stringent factor was coded for by either the relAins or relAnon phages (the latter in a sup+ cell); stringent factor was detected when the relAnon phages were used in a similar experiment with supD or supE host cells. The relAnon and relAins mutations could be crossed in haploid form in the E. coli chromosome. These recombinants grew with a normal doubling time, had a ppGpp pool which was between 70 and 100% compared with the classical relA strain, and underwent a normal carbon source shift-down. A restriction endonuclease map of the pyrG relA region of the specialized transducing phage is presented in which the position of the insertion element (recognized by a novel Hind III-cut site) defines the position of the relA gene. This position was verified by an analysis of the structure of five plasmids formed by cloning portions of the region in the pBR322 cloning vehicle. Our results indicate that the relA gene is not an essential cellular function, that there might be a second mechanism for the synthesis of basal level ppGpp in the cell and that the sole function of the relA gene is apparently the high level ppGpp synthesis triggered in response to deacylated tRNA.     

High-performance reversed-phase chromatographic mapping of 2-pyridylamino derivatives of xyloglucan oligosaccharides.

Xyloglucan oligosaccharides from cotton cell walls and tamarind seeds were derivatized with 2-aminopyridine and subsequently separated by reversed-phase chromatography (r.p.c.) using an octadecylsilyl silica stationary phase and aqueous-organic eluents with 0.01% (v/v) trifluoroacetic acid. The chromatographic behavior of the 2-pyridylamino derivatives of xyloglucan oligosaccharides was examined under a wide range of elution conditions, including gradient steepness and shape, initial acetonitrile concentration in the eluent, and pore size of the r.p.c. packings. Relatively steep acetonitrile gradients resulted in poor resolution of the different xyloglucan fragments, which is believed to be the result of acetonitrile-induced conformational changes. Under these circumstances the elution order of the derivatized xyloglucan oligosaccharides was such that the smaller fragments eluted from the column before the larger ones. R.p.c. packing with a 70-A pore size necessitated relatively high acetonitrile concentration in the eluent when compared with 300-A stationary phase. The r.p.c. mapping of 2-pyridylamino derivatives of xyloglucan oligosaccharides was best achieved when both a wide-pore octadecyl-silyl silica stationary phase and a shallow gradient with consecutive linear segments of increasing acetonitrile concentration in the eluent were employed. This combination yielded rapid r.p.c. maps of the xyloglucan fragments from different sources with high separation efficiencies and concomitantly high resolution. The effects of the nature of the sugar residues in the xyloglucan oligomers and their degree of branching on r.p.c. retention and selectivity are also highlighted.     

Expression of bacterial beta-galactosidase in animal cells

A recombinant plasmid containing the gene for bacterial β-galactosidase, situated close to the simian virus 40 early promoter, has been constructed. Transfection of CHO, L, and COS-1 cells with this plasmid led to the expression and appearance of the enzyme. Using this system, we have developed a series of promoter cloning vehicles capable of accepting promoter signals for animal genes.     

土壤水分条件对克隆植物互花米草表型可塑性的影响

在互花米草草滩挖掘沙蚕是海岸带常见的行为,会造成土壤结构松散,蓄水能力下降,局部土壤水分含量低.能否利用这些条件,降低互花米草种群的入侵性,并进而对互花米草的控制提供对策是一个重要的生态学命题.为此,实验模拟3种不同土壤蓄水条件,并测定互花米草在该条件下的形态与存活指标、克隆特征参数及生物量积累与分配格局.结果表明:土壤水分条件对互花米草的叶长和根状茎生物量均没有显著影响(p> 0.05);而其株高、分枝强度、克隆存活数、克隆存活率及地上生物量在各土壤水分条件间差异显著(p< 0.05);在低水分条件下,互花米草的芽数、基茎粗、地上生物量比和叶生物量比均显著低于其他两组处理(p< 0.05),地下生物量比则显著高于其他两组处理(p< 0.05);在中等水分条件下,互花米草的根状茎长、根状茎节数、地下生物量和茎生物量比与其他两组处理差异不显著(p> 0.05),而在其他两组处理间差异显著(p< 0.05);在高水分条件下,总生物量、茎生物量和根生物量显著高于其他两组处理(p< 0.05),根状茎生物量比则显著低于其他两组处理(p< 0.05),而这些指标在其他两组处理间均差异不显著(p> 0.05).由此推断,土壤水分条件适中有利于互花米草的生长扩张以占领有利的资源环境,而土壤水分条件低则抑制互花米草的生长繁殖,影响其种群延续.     

Distinct basolateral amygdala excitatory inputs mediate the somatosensory and aversive-affective components of pain

Pain is a multidimensional perception that includes unpleasant somatosensory and affective experiences; however, the underlying neural circuits that mediate different components of pain remain elusive. Although hyperactivity of basolateral amygdala glutamatergic (BLA^Glu) neurons is required for the somatosensory and emotional processing of pain, the precise excitatory inputs to BLA^Glu neurons and their roles in mediating different aspects of pain are unclear. Here, we identified two discrete glutamatergic neuronal circuits in male mice: a projection from the insular cortex glutamatergic (IC^Glu) to BLA^Glu neurons, which modulates both the somatosensory and affective components of pain, and a projection from the mediodorsal thalamic nucleus (MD^Glu) to BLA^Glu neurons, which modulates only the aversive-affective component of pain. Using whole-cell recording and fiber photometry, we found that neurons within the IC→BLA and MD→BLA pathways were activated in mice upon inflammatory pain induced by injection of complete Freund’s adjuvant (CFA) into their paws. Optical inhibition of the IC^Glu→BLA pathway increased the nociceptive threshold and induced behavioral place preference in CFA mice. In contrast, optical inhibition of the MD^Glu→BLA pathway did not affect the nociceptive threshold but still induced place preference in CFA mice. In normal mice, optical activation of the IC^Glu→BLA pathway decreased the nociceptive threshold and induced place aversion, while optical activation of the MD^Glu→BLA pathway only evoked aversion. Taken together, our results demonstrate that discrete IC^Glu→BLA and MD^Glu→BLA pathways are involved in modulating different components of pain, provide insights into its circuit basis, and better our understanding of pain perception.     

Local Recurrence of Soft Tissue Sarcoma Revisited: Is there a Role for “Selective” Radiation?

BackgroundRadiation therapy (RT) is often utilized in cases of high-grade soft tissue sarcoma (STS), but there remain situations where treatment is with surgical excision alone. Our goals were to determine (1) the local recurrence (LR) rate with and without perioperative RT and (2) associations between local recurrence, patient, tumor, and treatment variables.MethodsWe performed a retrospective review of 165 consecutive STS patients. A Cox proportional hazards model was used to investigate variables associated with local recurrence.ResultsLR occurred in 15/78 (19%) without RT, 4/29 (14%) with postoperative RT, and 0/58 with preoperative RT (p=0.002). We found increased rates of local recurrence at 24 months for myxofibrosarcoma (p=0.001) and no-RT (p=0.003). Myxofibrosarcoma accounted for 33 (20%) of the study patients and 12 (63%) of the local recurrences.ConclusionThe LR rate in patients treated with surgery alone was disproportionately attributable to myxofibrosarcoma (11/23 cases, 48%). Other subtypes demonstrated a lower rate of LR in the absence of RT (4/55 cases, 7%), and no LR occurred when final margins were >2 mm. In certain circumstances treatment with a negative margin surgical resection followed by close observation is justifiable. RT is effective and should continue to be considered routinely in myxofibrosarcoma or when surgical margins are inadequate. Level of Evidence: III