The gum exudates from Chloroxylon swietenia,Sclerocarya caffra,Azadirachta indica and Moringa oleifera

Analytical data are presented for the polysaccharide and proteinaceous components of the gum exudates from Chloroxylon swietenia and Sclerocarya caffra, and for the amino acid compositions of the exudates from Azadirachta indica (two specimens) and Moringa oleifera. The gums from C. swietenia and S. caffra contain 4-O-methylglucuronic acid, glucuronic acid, galactose and arabinose; rhamnose is absent. Amino acid analysis shows that proteinaceous material is present in the gums from C. swietenia, S. caffra and M. oleifera despite their low nitrogen content. Hydroxyproline accounts for 28 % of the amino acid content of S. caffra gum. In contrast, A. indica gum has a high nitrogen content but contains very little hydroxyproline.     

Potential application of a low-viscosity and high-transparency xanthan gum produced from Xanthomonas campestris CCTCC M2015714 in foods

Xanthan gum is commonly used as a thickener in food industry, while the usage of xanthan gum as a dietary fiber is restricted for its low additive volume. Herein, the potential use of a low-viscosity and high-transparency xanthan gum as a dietary fiber was evaluated in vitro. This new xanthan shows better transparency and faster dissolution rate than most commercial products, and its viscosity increases along with the treatment of freeze–thaw cycles at ?20°C. Moreover, this new xanthan can absorb heavy metals (Pb, Cd, Cu) and retard starch digestion by glucoamylase. In summary, this new xanthan could be potentially used as a dietary fiber or fiber ingredient for preventing and treating diabetes, hyperlipemia, heavy metal poisoning, and cardiovascular diseases effectively.     

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.     

魔芋葡甘露低聚糖的酶法制备工艺的初步研究

利用β-甘露聚糖酶产品水解魔芋胶制备魔芋葡甘露低聚糖的工艺条件。在加样顺序、pH、酶添加量、时间、温度等单因素试验的基础上,进一步通过正交试验确定的最佳工艺条件为:魔芋胶浓度10g/L,酶添加量为100U/g,pH5.5,45℃条件下,酶解时间1.5h。再利用酵母发酵去除可发酵性糖的方法,以获得最终产物为100%的魔芋葡甘露低聚糖。     

槐豆胶的流变性及与黄原胶的协效性研究

本文主要对槐豆胶的流变性及槐豆胶与黄原胶的协效增稠性和协效凝胶性进行了研究。结果表明:槐豆胶具有较高的粘度,当胶浓度为1％时,其粘度为660mpa·s;浓度、剪切力、温度、酸碱、冻融等变化与槐豆胶的粘度都有较大的关系;槐豆胶还有一非常显著的特性即是与黄原胶的协效增稠性和协效凝胶性,可作为理想的黄原胶的增稠剂和凝胶剂。     

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     

Isolation and properties of an endo-β-mannanase-producing Bacillus sp. LX114 capable of degrading guar gum

Endo-β-mannanase, catalyzing the random hydrolysis of β-1,4-mannosidic linkage in the backbone of (hetero) mannan, can increase feed conversion efficiency of animal feed or form functional mannanooligosaccharides. In this study, a gram-positive, straight-rod, facultative anaeorobic bacterium producing endo-β-mannanase was isolated from soil sample. The isolate only fermented glucose, galactose, sorbose, and raffinose to acid. The test in hydrogen sulfide production was positive. Combining the data acquired from phenotypic analysis and phylogenetic analysis based on 16S rRNA gene sequences, this strain presumably represented a novel species of the genus Bacillus and was designated as LX114. The strain LX114 could break down guar gum molecules, leading to a rapid decrease of the viscosity of guar gum solutions. Endo-β-mannanase activity was also detected in the culture supernatant. The isolate LX114 would be useful for potential application in degrading plant cell walls for increasing feed conversion efficiency and formation of functional oligosaccharides.