沙蒿组织培养植株再生

沙蒿种子灭菌后,接入ＭＳ无激素培养基得到无菌苗。取２０天无菌苗子叶切成小块,接入含２,４－Ｄ的ＭＳ培养基诱导愈伤组织,并在同样培养基上进行继代增殖。愈伤组织在含６－ＢＡ,ＮＡＡ的ＭＳ培养基上分化得到芽。将芽转至含ＩＡＡ的１／２ＭＳ培养基上形成根,从而得到完整植株。同时对影响沙蒿组织培养的一些因素进行了研究。结果表明培养基中２,４－Ｄ含量（０．５－２ｍｇ／Ｌ）越高,沙蒿愈伤组织生长越快,而褐化发生时     

Locomotor behavior and feeding ecology of the panamanian tamarin (Saguinus oedipus geoffroyi,callitrichidae, primates)

The Callitrichidae are a family of New World primates that exhibit a complex of behavioral and morphological characters reputedly similar to those of tree squirrels of the genus Sciurus.In particular, the locomotor behavior of tamarins and marmosets has been described as “squirrel-like. ” In this paper I describe a field investigation of the locomotor behavior and ecology of the Panamanian tamarin (Saguinus oedipus geoffroyi)and the redtailed squirrel (Sciurus granatensis).From January through August 1978, a total of 1200 hr was spent observing freeranging populations of tamarins and tree squirrels in an area of secondary forest on the Pacific Coast of Panama. Observations were made using an instantaneous time sampling technique. Individual activity records were collected on focal animals and recorded at 2.5-min intervals throughout the day. The following information was collected: (a) nature and structure of the substrate exploited, (b) activities on these supports and/or types of resources procured, and (c) body posture involved in the use of these supports. Data presented indicate major differences in substrate preference and positional behavior in tamarins and tree squirrels. Unlike squirrels, tamarins avoid vertical and sharply inclined supports during travel. Movements through the canopy is accomplished by a series of long leaps which begin and end on thin terminal supports. However, the Panamanian tamarin spent numerous hours clinging to large vertical trunks while feeding on plant exudate. Gums comprise 23.O% of the noninsect portion of the tamarin diet. The relationships between small body size, claw-like nails, substrate preference, and positional behavior are discussed. Claw-like nails enable this primate to exploit a food resource that would otherwise be inaccessible. The interrelationship between environment, behaviour, and morphology provides a frameworks from which to understand callitrichid adaptations. These adaptations are not convergent with those of the sciurid rodents. An earlier draft of this paper was presented at the 48th Annual Meeting of the American Association of Physical Anthropologists, San Francisco, April 1979.     

白沙蒿不同地理种群遗传分化的ISSR分析

运用ISSR技术,对白沙蒿的5个种群进行遗传分化的分析。12个引物在108个个体中共扩增出222个位点,其中,多态位点为218个,多态位点百分率为98.20%,Shannon多样性指数为0.315 4,具有高的多态性。种群间的遗传分化系数（G_st）为0.076 7,与AMOVA分析的结果一致（Ф_st为7.96%）,表明绝大多数的遗传变异存在于种群内部。各种群间遗传一致度高达98%以上,遗传距离很小,基因流达3.008 2,均表现出白沙蒿各种群存在着广泛的基因交流,有着很小的遗传分化。     

Adding gelling agents to cotton ovule culture media leads to subtle changes in fiber development

Summary Young cotton (Gossypium hirsutum) ovules will produce fiber in vitro when floated on a defined culture medium. Our laboratory is interested in examining the effects of altered gravity environments on fiber development as a model for the effects of gravity on cell expansion and cellulose biosynthesis. Since liquid culture media are unsuitable for altered gravity experiments, addition of gelling agents to cotton ovule culture media is necessary. In this study we have systematically examined the effects of four gelling agents at several concentrations on fiber production in culture. A rapid screening method using toluidine blue O staining indicated that after 3 wk in culture, fiber growth on 0.15% (wt/vol) Phytagel™ medium was similar to fiber growth on liquid medium. More detailed analysis of fiber development revealed that fiber length was not influenced by the addition of Phytagel™. Accumulation of cellulose, however, was reduced 50–60% compared with fibers produced in liquid media after 3 wk in culture. The fiber cellulose content rose with additional time in culture for both solid and liquid media treatments. By 4 wk in culture, the difference in cellulose content of fiber cell walls grown on solid versus liquid media was less than 20%. This variance in growth response on gelled media could be due to differences in media matric potential, to the immobility of ions trapped within the gel, or to toxicity of contaminants copurifying with Phytagel™. By identifying why ovule growth and fiber cellulose biosynthesis are reduced in cultures grown on gelled media, it will be possible to reveal new information about these processes in system that is less complicated than physiological systems at the whole plant level. Names of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.     

A novel analytical ultracentrifugation based approach to the low resolution structure of gum arabic

Under investigation are the structural properties of gum arabic, an industrially important biopolymer for use as a stabilizer or in drug delivery, using Analytical Ultracentrifugation—a well‐established, matrix‐free probe for macromolecular size and shape. These results are combined with chromatographically‐coupled methods (multi‐angle light scattering, differential press imbalance viscometry) to provide a global analysis of its structure in varying ionic strength conditions. This analysis indicates that gum Arabic may have a compact, elliptical structure in solution, the significance of which for biotechnological use is indicated. This modelling method can be applied to other biopolymers and synthetic polymers. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 618–625, 2016.     

白芨多糖胶-瓜尔胶复配溶液的流变性

考察了瓜尔胶溶液和白芨多糖胶-瓜尔胶复配溶液的流变特性。两组溶液呈现典型的假塑性,不同浓度下两组溶液表观黏度(ηa)随剪切速率(τ)的变化可以用Ostwald-Dewaele方程描述。白芨多糖胶和瓜尔胶复配产生协同增效作用,复配溶液的ηa大于单一组分的白芨多糖胶溶液或瓜尔胶溶液的ηa。复配溶液中白芨多糖胶与瓜尔胶的最佳配比是质量比为9∶1。     

Cross-linked guar gum microspheres: A viable approach for improved delivery of anticancer drugs for the treatment of colorectal cancer

In the present work, guar gum microspheres containing methotrexate (MTX) were prepared and characterized for local release of drug in the colon, which is a prerequisite for the effective treatment of colorectal cancer. Guar gum microspheres were prepared by the emulsification method using glutaraldehyde as a cross-linking agent. Surface morphological characteristics were investigated using scanning electron microscopy. Particle size, shape, and surface morphology were significantly affected by guar gum concentration, glutaral dehyde concentration, emulsifier concentration (Span 80), stirring rate, stirring time, and operating temperature. MTX-loaded microspheres demonstrated high entrapment efficiency (75.7%). The in vitro drug release was investigated using a US Pharmacopeia paddle type (type II) dissolution rate test apparatus in different media (phosphate-buffered saline [PBS], gastrointestinal fluid of different pH, and rat cecal content release medium), which was found to be affected by a change to the guar gum concentration and glutaraldehyde concentration. The drug release in PBS (pH 7.4) and simulated gastric fluids followed a similar pattern and had a similar release rate, while a significant increase in percent cumulative drug release (91.0%) was observed in the medium containing rat cecal content. In in vivo studies, guar gum microspheres delivered most of their drug load (79.0%) to the colon, whereas plain drug suspensions could deliver only 23% of their total dose to the target site. Guar gum microspheres showed adequate potential in achieving local release of drug in in vitro release studies, and this finding was further endorsed with in vivo studies. Published: September 8, 2006     

XCCNAU—92发酵生产黄原胶的适宜条件

XCCNA－92发酵生产黄原胶的适宜条件是：好氧,发酵温度为30℃,培养基起始pH为7.0,接种量6％,发酵周期60h。利用最佳培养基配方,在30℃,150r／min条件下发酵72h,工业级黄原胶产量达40.84g／L,发酵液粘度86000cp,丙酮含量4．1％,碳源转化率达68.1％。     

Carbamoylethylation of guar gum

Carbamoylethylation of guar gum was carried out with acrylamide in presence of sodium hydroxide under different reaction conditions. Variables studied were concentration of sodium hydroxide, acrylamide, guar gum as well as reaction temperature and time. The nitrogen content, carboxyl content and total ether content were determined. Rheological properties of carbamoylethyl guar gum solutions showed non-Newtonian pseudoplastic behavior regardless of the %N. At a constant rate of shear, the apparent viscosity of carbamoylethyl guar gum solutions decreases with the increase in %N of the product.     

蓝桉凋落叶分解对菠菜生长及光合特性的影响

通过盆栽试验,模拟蓝桉(Eucalyptus globulus)凋落叶在土壤中分解对受体植物菠菜(Spinacia oleracea)生长及光合特性的影响,设置L30(30 g/盆)、L60(60 g/盆)、L90(90 g/盆)和L120(120 g/盆)4个凋落叶施用水平,对照(CK)不加凋落叶。结果表明:(1)在分解30 d时,低量的凋落叶(L30)未抑制菠菜生物量的积累,而中量和高量处理(L60、L90和L120)下其生物量显著降低(P0.05);在凋落叶分解50 d后,蓝桉凋落叶的化感抑制效应已经减弱,仅L120仍然抑制菠菜生物量的积累;(2)一定量的凋落叶(L30和L60)对菠菜叶绿素的合成有促进作用,而凋落叶超过一定量时(L120)转为抑制作用,在凋落叶分解28 d时相对不明显,40 d后逐渐显现;(3)经凋落叶处理的菠菜叶片胞间CO2浓度(Ci)、气孔导度(Gs)及蒸腾速率(Tr)均显著高于对照(CK)(P0.05),而净光合速率(Pn)在L30处理下最高,L60和L90处理与CK差异不显著,仅L120处理显著低于CK(P0.05);(4)光响应与CO2响应曲线的特征参数表观量子效率(AQY)、最大净光合速率(Pmax)、光饱和点(Lsp)、光补偿点(Lcp)、暗呼吸速率(Rd)、Ru BP表观羧化效率(CE)和光呼吸速率(Rp)在L30处理下高于CK,其余凋落叶处理均低于CK,而CO2饱和点(Csp)、CO2补偿点(Ccp)随凋落叶量的增加而升高。综合各指标可见,少量的蓝桉凋落叶分解(L30)可通过增加叶绿素含量,提高对光和CO2的利用能力促进菠菜的光合作用,进而促进其生长,而凋落叶超过一定量时(L90—L120)则起到相反的作用。