Starch-based coatings for colon-specific delivery. Part II: Physicochemical properties and in vitro drug release from high amylose maize starch films

This work reports an investigation into free-film properties of a high amylose maize starch-based film coating that has been used in the preparation of formulations for drug delivery to the colon (WO 2008/012573 A1) and relates these properties to in vitro drug release from pellets.Maize starch/ethylcellulose free films were prepared and characterised by scanning electron microscopy (SEM), light microscopy, modulated differential scanning calorimetry (mDSC), Fourier-transform infrared (FT-IR), X-ray and % swelling in aqueous fluids with pH conditions similar to the stomach and small intestine. 5-ASA release from film-coated pellets was tested in enzyme free simulated gastric fluid and phosphate buffer pH 7.2. Selected formulations were further assessed in simulated gastric and intestinal fluids containing pepsin and pancreatin, respectively.The free films prepared were smooth and homogeneous in their appearance. The two polymers are immiscible, and neither mDSC nor FT-IR could detect interactions between them. Films made from high amylose starches were found to have a considerably lower swelling ability than high amylopectin-based films, and they suppressed drug release in the enzyme free media successfully.5-ASA release from pellets coated with mixtures of high amylose starches (Hylon^® VII, Hylon^® V or LAPS) and Surelease^® in a ratio of 1 to 2 w/w was found to be minimal in simulated gastric and intestinal fluids. This suggests that these mixed films provide starch domains that are resistant to the enzymes present in the upper GI tract and thus can potentially be used in the preparation of colon-specific delivery devices. Starches with a minimum amylose content of 56% such as the starches used in this study (Hylon^® VII and Hylon^® V) are preferred, and although pure amylose can also be used this is not essential.     

From the Cover: Transgenic multivitamin corn through biofortification of endosperm with three vitamins representing three distinct metabolic pathways

Vitamin deficiency affects up to 50% of the world''s population, disproportionately impacting on developing countries where populations endure monotonous, cereal-rich diets. Transgenic plants offer an effective way to increase the vitamin content of staple crops, but thus far it has only been possible to enhance individual vitamins. We created elite inbred South African transgenic corn plants in which the levels of 3 vitamins were increased specifically in the endosperm through the simultaneous modification of 3 separate metabolic pathways. The transgenic kernels contained 169-fold the normal amount of β-carotene, 6-fold the normal amount of ascorbate, and double the normal amount of folate. Levels of engineered vitamins remained stable at least through to the T3 homozygous generation. This achievement, which vastly exceeds any realized thus far by conventional breeding alone, opens the way for the development of nutritionally complete cereals to benefit the world''s poorest people.     

Subchronic feeding study of grain from herbicide-tolerant maize DP-Ø9814Ø-6 in Sprague-Dawley rats

This 13-week feeding study conducted in Sprague-Dawley rats evaluated the potential health effects from long-term consumption of a rodent diet formulated with grain from genetically modified (GM), herbicide-tolerant maize DP-Ø9814Ø-6 (98140; trade name Optimum^® GAT^® (Optimum^® GAT^® is a registered trademark of Pioneer Hi-Bred)). Metabolic inactivation of the herbicidal active ingredient glyphosate was conferred by genomic integration and expression of a gene-shuffled acetylase coding sequence, gat4621, from Bacillus licheniformis; tolerance to acetolactate synthase (ALS) inhibiting herbicides was conferred by overexpression of a modified allele (zm-hra) of the endogenous maize ALS enzyme that is resilient to inactivation. Milled maize grain from untreated (98140) and herbicide-treated (98140+Gly/SU) plants, the conventional non-transgenic, near-isogenic control (091), and three commercial non-transgenic reference hybrids (33J56, 33P66, and 33R77) was substituted at concentrations of 35–38% w/w into a common rodent chow formula (PMI^® Nutrition International, LLC Certified Rodent LabDiet^® 5002) and fed to rats (12/sex/group) for at least 91 consecutive days. Compared with rats fed diets containing grain from the conventional near-isogenic control maize, no adverse effects were observed in rats fed diets containing grain from 98140 or 98140+Gly/SU maize with respect to standard nutritional performance metrics and OECD 408-compliant toxicological response variables [OECD, 1998. Section 4 (Part 408), Health Effects: Repeated Dose 90-Day Oral Toxicity Study in Rodents, Guideline for the Testing of Chemicals. Organisation of Economic Co-operation and Development, Paris, France]. These results support the comparative safety and nutritional value of maize grain from genetically modified Optimum^® GAT^® and conventional, non-transgenic hybrid field corn.     

Sweetpotato-based complementary food would be less inhibitory on mineral absorption than a maize-based infant food assessed by compositional analysis

The availability of micronutrients from sweetpotato-based complementary foods (CFs): oven-toasted and roller-dried ComFa, and from a maize-based infant food, enriched Weanimix, was compared using phytate/mineral molar ratios, polyphenols and β-carotene levels. The phytate/calcium, iron and zinc molar ratios of approximately 0.17, 1 and 15 predict better absorption of calcium, iron and zinc respectively. Generally, the sweetpotato-based CFs had at least half the phytate/mineral ratios of enriched Weanimix. The phytate/iron ratio in both the sweetpotato- and the maize-based CFs was greater than 1. Only the ComFa formulations had phytate/zinc ratio lower than 15. The level of polyphenol (iron inhibitor) was similar for the formulations. Only the sweetpotato-based CFs contained measurable levels of β-carotene, a possible iron enhancer. The lower phytate/mineral ratios and the β-carotene level of the sweetpotato-based CFs suggest that calcium, iron and zinc absorption could be better from them than from the maize-based infant food.     

大豆和玉米加工产品中外源转基因成分检测技术的建立

目的：建立检测大豆和玉米加工产品中转基因成分的PCR技术.方法：采用PCR技术检测CaMV 35S启动子,并进一步通过PCR检测RoundUp Ready Soybean（RRS）和Bt176 Maximaizer的特异性DNA片段,判断大豆和玉米加工产品中是否含相应转基因成分.结果：在1份豆粕和豆腐样品中检测到了RoundUp Ready大豆特异性的498bp片段,而在玉米粒样品中检测到了Bt176特异性转基因成分.PCR检测的灵敏度达到0.1%,稳定性良好.结论：PCR技术检测外源基因是灵敏和准确的,可以广泛地应用到转基因作物及其加工产品的转基因成分检测中.     

Electron microscopic investigation of nitrobenzene distribution and effect on plant root tip cells ultrastructure

Electron microscopic radioautography demonstrated the penetration of [1-6(14)C]nitrobenzene in maize and soybean root tip cells: radioactive label was detected in cell wall, plasmalemma, nuclei, and cytoplasm. Among cytoplasmic organelles, the highest label was found in mitochondria and plastids. [1-6(14)C]nitrobenzene and/or products of its transformation accumulated in vacuoles. Study of the action of different concentrations of nitrobenzene on cell ultrastructural organization revealed the following picture. Nitrobenzene concentration up to 0.015 mM was harmless for plant cells. Increase of nitrobenzene concentration from 0.015 to 1.5 mM induced several pathological changes, up to the complete destruction of cells. The most damaged organelles were nuclei, mitochondria, and plastids. In the presence of 0.15 mM nitrobenzene the intensification of contacts among cell organelles, especially between endoplasmic reticulum and mitochondria/plastids, was observed. The data indicate some coordination between detoxication activity and energy metabolism during cell reaction to xenobiotic toxicity.     

Crossing over as assessed by late recombination nodules is related to the pattern of synapsis and the distribution of early recombination nodules in maize

Recombination nodules (RNs) are multicomponent proteinaceous ellipsoids found in association with the synaptonemal complex (SC) during prophase I of meiosis. Numerous early RNs (ENs) are observed during zygotene, and they may be involved in homologous synapsis and early events in recombination. Fewer late RNs (LNs) are observed during pachytene, and they occur at crossover sites. Here we describe the pattern of synapsis and the distribution of ENs and LNs in maize. Synapsis starts almost exclusively at chromosome ends, although later in zygotene there are many interstitial sites of synaptic initiation. ENs do not show interference, except possibly at distances ≤0.2 μm. The frequency of ENs is higher on distal compared to medial SC segments, and the highest concentration of ENs occurs at synaptic forks. The number of ENs on an SC segment does not change during zygotene. These observations are interpreted to indicate that ENs are assembled at synaptic forks. Like ENs, LNs are more concentrated distally on bivalents but, unlike ENs, LNs show interference. A model is presented that relates the pattern of synapsis and ENs to the pattern of late nodules and crossing over. This revised version was published online in July 2006 with corrections to the Cover Date.     

Serological relationships among maize rough dwarf-like viruses.

The serological relationships of most of the known maize rough dwarf-like viruses were investigated using immune electron microscopy and gel-diffusion tests to detect the reactions of the inner capsids and the B spikes of the virus particles. The antigens were those of maize rough dwarf virus (MRDV), pangola stunt virus (PSV), cereal tillering disease virus (CTDV), oat sterile dwarf virus (OSDV), Arrhenatherum blue dwarf virus (ABDV) and Lolium enation virus (LEV). The sera were those against MRDV, rice black streaked dwarf virus (RBSDV), and Fiji diseases virus (FDV). These were absorbed with healthy material and dsRNA if necessary. The results showed that MRDV, RBSDV, PSV, and CTDV were serologically related in both the inner capsid and the B spike. However, MRDV, PSV, and CTDV did not react with FDV antiserum (RBSDV was not available). OSDV, ABDV, and LEV did not react with sera against MRDV, RBSDV, or FDV. We conclude that the MRDV-like viruses fall into at least three serological groups: (I) MRDV, RBSDV, PSV, and CTDV (interrelated, but not related to II and III); (II) FDV (not related to I and III); (III) OSDV, ABDV, and LEV (not related to I and II, but interrelationships unknown).     

长效复混肥的农田效应

长效玉米专用肥 (免追旺 )在吉林省 7个县 (市 )进行田间试验。结果表明 ,其 1kg养分增收玉米 4 1kg,养分回报率比常规一次性施肥提高 19.8% ,比多施 2 0 %的 15 15 15复混肥提高 2 3.1% ;分别增收 4 85元 / hm2和 2 6 8元 / hm2 。