DIFFERENTIAL GERMINATION AND DEVELOPMENTAL RESPONSES OF BLETIA PURPUREA (ORCHIDACEAE) TO MANNITOL AND SORBITOL IN THE PRESENCE OF SUCROSE AND FRUCTOSE

Orchid seeds are energy-limited at dispersal and require infection by fungi in situ or an exogenous carbohydrate source when grown in vitro. While they are able to utilize a wide range of carbohydrates, polyols (sugar alcohols) are not known to enhance germination and early seedling development. In this study, we examined whether two polyols, mannitol and sorbitol, are inhibitory to germination and development or simply not utilized during germination using Bletia purpurea as a model orchid. When seeds were cultured with germination-promoting sugars (sucrose and fructose), sorbitol had little or no effect on germination and slightly inhibited seedling development at high molarities. Seeds cultured in the presence of mannitol and sucrose or fructose at 1 and 10 mmol exhibited enhanced germination, seedling development and rhizoid production. Mannitol alone did not enhance germination over control. We hypothesize that mannitol is taken up by Bletia purpurea embryos, leading to reduced osmotic stress and allowing for enhanced production of dehydration-sensitive rhizoids.     

Use of alkaline soil extracts for 13C n.m.r. characterization of humic substances

Previous solution ¹³C n.m.r. studies of soil organic matter have been confined to isolated humic or fulvic acid fractions. A study of 10 crude alkaline extracts from five New Zealand topsoils has now shown that such purification is unnecessary. Spectra were not noticeably broadened by co-extracted iron in concentrations up to 2 mg cm^?3. Optimized pulse parameters were similar to those reported for a solution of a purified humic acid. Relaxation results support a generalized model for humic material, in which aromatic structures, carbohydrates, amino acids and polymethylene chains are linked together to form flexible macromolecules. Relative contributions from each component varied from soil to soil.     

Induction of enzyme activity in cell culture: a rapid screen for detection of planar polychlorinated organic compounds.

Induction of aryl hydrocarbon hydroxylase (AHH) activity in rat hepatoma cell line serves as a simple and rapid method to detect minute (pg) amounts of certain classes of compounds, e.g., dibenzo-p-dioxins, dibenzofurans, and biphenyls. This method may provide a quick screen for such substances in extracts from foods prior to chemical identification. AHH activity is measured by conversion of benzo[a]pyrene (BP) to 3-hydroxy BP in homogenized cell extracts from control and treated cultures and is reported as pmol product formed/mg protein/min. Substances screened by this method include polyhalogenated analogs of dibenzo-p-dioxin (24 compounds), dibenzofuran (11 compounds), biphenyl (7 compounds), and extracts from several food sources. Response of the most reactive compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was used to prepare a standard curve, and the AHH activity induced by mole doses of test substance is reported as an ED50 response (the estimated dose needed to produce 50% maximum enzyme induction). The AHH activity induced by food extracts is equated to the standard curve and reported as TCDD equivalents. A potent ED50 response in cell culture appears to correlate well with known toxic responses in other mammalian and avian systems for certain test substances. This correlation suggests that the cell culture enzyme induction method is a useful model for screening food extracts that are suspected to be contaminated with polychlorinated planar substances. A collaborative study would demonstrate the reproducibility of the method.     

秸秆捆烧技术及其排放特性研究进展

秸秆捆烧技术是实现农业秸秆能源化清洁利用的有效途径之一,但实际运行中仍然存在燃烧不充分、NO_X和颗粒物生成机理不清晰、烟气污染物排放较高等问题。该文综述了秸秆捆烧技术最新研究进展,简述了秸秆捆燃烧反应原理和秸秆捆燃烧特性,重点分析了秸秆捆烧过程中颗粒物、NO_X和CO等污染物产生及减排方法,系统总结了国内外秸秆捆烧技术类型、原理及特点等研究进展。通过全球文献检索,分析了秸秆捆烧技术研究热点、主要研究机构以及发展趋势,并评价了秸秆捆烧供暖运行成本。建议深入开展秸秆捆烧燃烧与污染物排放特性研究,开展秸秆捆烧锅炉结构及配风工艺优化,从源头减少烟气污染物生成,为实现秸秆清洁能源化利用提供参考。     

General food semiochemicals attract omnivorous German cockroaches, Blattella germanica

Stale beer and peanut butter are effective baits for the German cockroach (GCRs), Blattella germanica (L.) (Dictyoptera: Blattellidae). In still-air arena olfactometer experiments it was previously shown that headspace volatile extracts of peanut butter and solvent extract of beer attract male GCRs. The objective of this study was to identify the semiochemicals that mediate attraction of GCRs to these sources. Coupled gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric (MS) analyses of these attractive extracts, or fractions thereof, and of synthetic standards revealed many candidate semiochemicals. Elaborate olfactometer experiments determined that 1-hexanol from peanut butter, and ethanol and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) from beer, are the key semiochemicals of these food sources. 1-Hexanol is a well-known headspace volatile of decomposing lipids, ethanol conveys food fermentation, and DDMP with a caramel-type flavor has been found in several types of food. By responding to these rather general food-derived compounds, the omnivorous GCRs appear to exploit semiochemicals that indicate the presence of various food components, such as lipids and carbohydrates. Synthetic equivalents of these semiochemicals may be formulated as baits or be added to, and thus enhance the attractiveness of, natural food sources as trap or insecticidal baits.     

用曲轴箱增压改善单缸四冲程柴油机性能研究

针对单缸四冲程柴油机保有量大，应用范围广，而又普遍存在油耗、排污相对偏高的问题，结合单缸四冲程柴油机工作原理及结构特点，在X195柴油机空气滤清器、进气管和曲轴箱之间增设一个带单向阀片的节能增压装置，利用曲轴箱内容积的变化(靠活塞的工作反面泵气)，把进入空气滤清器的清洁气体和从气缸内漏入曲轴箱内的气体一齐压入气缸，使发动机的充气效率得到提高，漏入曲轴箱内的可燃气体再次利用，从而达到降低油耗，减少排放污染的目的。增设的节能增压装置安装方便、结构简单、工作可靠、制造成本低、不需要单独设置驱动机构。X195柴油机安装节能增压装置前、后的性能对比试验，在云南金马柴油机总厂发动机试验室按照国标、部标的规定进行。实验证明，在不消耗原机功率，不改变原机任何结构的前提下，安装节能增压装置的发动机提高了功率，降低了油耗，减少了排放污染，该节能增压装置对改善单缸四冲程柴油机的性能是行之有效的。     

Extracts of Maqui ( Aristotelia chilensis ) and Murta ( Ugni molinae Turcz.): sources of antioxidant compounds and α-Glucosidase/α-Amylase inhibitors

The objective of this work was to evaluate the antioxidant and antihemolytic activities of crude, aqueous, and organic-aqueous extracts of maqui ( Aristotelia chilensis ) and murta ( Ugni molinae Turcz.), together with their inhibiting effect on enzymes involved in the metabolism of carbohydrates. Radical scavenging activity, inhibition of linoleic acid oxidation in a micellar system, antihemolytic activity, and inhibition of α-amylases and α-glucosidases were analyzed. Crude extracts of maqui leaves and fruits were found to be important sources of polyphenolic compounds, showing 69.0 ± 0.9 and 45.7 ± 1.1 mg GAE/g dm, respectively. Polyphenols from maqui leaves were active as antioxidants and antihemolytic compounds (p < 0.05), showing a noncompetitive inhibiting effect on α-glucosidase. Flavan-3-ol polymers and glycosylated flavonols, such as quercetin glucoside and kaempferol glucoside, were tentatively identified in extracts. This preliminary observation provides the basis for further examination of the suitability of polyphenol-enriched extracts from maqui and murta as nutritional or medicinal supplements with potential human health benefits.     

Apples prevent mammary tumors in rats

Regular consumption of fruits and vegetables has been consistently shown to be associated with reduced risk of developing chronic diseases such as cancer and cardiovascular disease. Apples are commonly consumed and are the major contributors of phytochemicals in human diets. It was previously reported that apple extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. Phytochemicals, including phenolics and flavonoids, are suggested to be the bioactive compounds contributing to the health benefits of apples. Here it is shown that whole apple extracts prevent mammary cancer in a rat model in a dose-dependent manner at doses comparable to human consumption of one, three, and six apples a day. This study demonstrated that whole apple extracts effectively inhibited mammary cancer growth in the rat model; thus, consumption of apples may be an effective strategy for cancer protection.     

Use of ferrous hydroxide for determination of nitrate in soil extracts

Abstract

A simple steam distillation method of determining nitrate is described that is not subject to interference by substantial amounts of phosphate or silicate. It involves use of FeSO₄ and MgO for reduction of nitrate to ammonia. The method is rapid and precise, and tests reported show that it is satisfactory for nitrate analysis of soil extracts.     

Insulin-like biological activity of culinary and medicinal plant aqueous extracts in vitro

To evaluate the possible effects on insulin function, 49 herb, spice, and medicinal plant extracts were tested in the insulin-dependent utilization of glucose using a rat epididymal adipocyte assay. Cinnamon was the most bioactive product followed by witch hazel, green and black teas, allspice, bay leaves, nutmeg, cloves, mushrooms, and brewer's yeast. The glucose oxidation enhancing bioactivity was lost from cinnamon, tea, witch hazel, cloves, bay leaf and allspice by poly(vinylpyrrolidone) (PVP) treatment, indicating that the active phytochemicals are likely to be phenolic in nature. The activity of sage, mushrooms, and brewers's yeast was not removed by PVP. Some products such as Korean ginseng, flaxseed meal, and basil have been reported to be effective antidiabetic agents; however, they were only marginally active in our assay. Our technique measures direct stimulation of cellular glucose metabolism, so it may be that the active phytochemicals in these plants improve glucose metabolism via other mechanisms or that this in vitro screening is not a reliable predictor of hypoglycemic effects in vivo for some products. In summary, the positive effects of specific plant extracts on insulin activity suggest a possible role of these plants in improving glucose and insulin metabolism.     

Genotoxicity of snow in the Montreal metropolitan area

Snow is capable of scavenging particle-bound, mutagenic organic pollutants from the atmosphere. Between storms snow can act as a mechanical filter for airborne particulates and dry atmospheric fallout can contribute to contamination of the snowpack. In urban areas snow cover can store contaminants and provide a sensitive, time integrated record of local air contamination. We examined the genotoxicity of snow collected from 14 sites in the Montréal metropolitan area. Snow contaminants were extracted using dichloromethane and the genotoxicity of the extracts measured using the SOS Chromotest. Only one extract elicited a positive response in the absence of a metabolic activation mixture. Sites which provided genotoxic samples are diverse in nature. Some sites are adjacent to highways and might be expected to receive genotoxic contaminants from internal combustion vehicles. Extracts of snow from regional dump sites were not genotoxic. Mean ambient carbon monoxide and nitrogen dioxide levels were significantly higher at sites which provided genotoxic snow samples. The mean ambient concentration of suspended particulates at the positive sites was not significantly different from the concentration at the negative sites. However, a significant linear relationship was identified between the SOS response inducing potency (SOSIP) of the genotoxic samples and the ambient level of suspended particulates. The results presented confirm the presence of genotoxic material in urban snow and demonstrate that the SOS Chromotest can be used to rapidly screen complex environmental extracts for genotoxicity. High ambient levels of carbon monoxide, nitrogen dioxide measured at positive sites, and the relationship between SOSIP and the concentration of airborne particulate matter, suggests that the putative genotoxicants are fuel combustion by-products. This conclusion, while supported by previous research on atmospheric, particle-bound mutagens, is still speculative.     

Influence of carbohydrates on the interaction of procyanidin B3 with trypsin

The biological properties of procyanidins, in particular their inhibition of digestive enzymes, have received much attention in the past few years. Dietary carbohydrates are an environmental factor that is known to affect the interaction of procyanidins with proteins. This work aimed at understanding the effect of ionic food carbohydrates (polygalacturonic acid, arabic gum, pectin, and xanthan gum) on the interaction between procyanidins and trypsin. Physical-chemical techniques such as saturation transfer difference-NMR (STD-NMR) spectroscopy, fluorescence quenching, and nephelometry were used to evaluate the interaction process. Using STD-NMR, it was possible to identify the binding of procyanidin B3 to trypsin. The tested carbohydrates prevented the association of procyanidin B3 and trypsin by a competition mechanism in which the ionic character of carbohydrates and their ability to encapsulate procyanidins seem crucial leading to a reduction in STD signal and light scattering and to a recovery of the proteins intrinsic fluorescence. On the basis of these results, it was possible to grade the carbohydrates in their aggregation inhibition ability: XG > PA > AG ? PC. These effects may be relevant since the coingestion of procyanidins and ionic carbohydrates are frequent and furthermore since these might negatively affect the antinutritional properties ascribed to procyanidins in the past.     

Effect of steam explosion treatment on barley bran phenolic compounds and antioxidant capacity

A steam explosion pretreatment process followed by methanol extraction has been applied for releasing and extracting phenolic compounds, as well as other effective components, from barley bran. The steam explosion treatment was performed at different temperatures ranging from 210 to 250 °C, with a residence time of 30 s. The effect of residence time was also studied in the range 10 s to 120 s at 220 °C. The extracts were evaluated for their total soluble phenolic content (TSPC) including total free phenolic acids (TFPC) and total soluble conjugates (TSC), identified phenolic acids, total antioxidant capacity (TAC), water-soluble carbohydrates (WSC) and total methanol extracts (TME). High-performance liquid chromatography (HPLC) coupled with a photodiode array detector (PDA) was used in this study for the analysis of p-coumaric acid and ferulic acid in barley bran before and after steam explosion. Our results indicate that TSPC and TAC increased with residence time. They also increased dramatically with temperature up to 220 °C. After steam explosion at 220 °C for 120 s, the TSPC reached 1686.4 gallic acid equivalents mg/100 g dry weight, which was about 9-fold higher than that of the untreated sample. The TSPC and TAC obtained were highly positively correlated (r = 0.918-0.993), which meant that the increase of TAC for the steam explosion pretreated barley bran extracts was due, at least in part, to the increase of TSPC in the methanol soluble fraction. Also, under optimum conditions, the WSC in aqueous solution was 5 times as much as that of the untreated sample, which demonstrated that steam explosion also hydrolyzes carbohydrates into water-soluble sugars. It can be concluded that a proper and reasonable steam explosion pretreatment could be applied to release the bound phenolic compounds and enhance the antioxidant capacity of barley bran extracts.     

Simple detection method of powerful antiradical compounds in the raw extract of plants and its application for the identification of antiradical plant constituents

A simple detection method for a powerful radical scavenging compound in a mixture containing a large variety of compounds, such as the raw extract of edible plants, was developed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) as the radical reagent. The method was established on the basis of the features of the typical chain-breaking antioxidation reaction mechanism, which suggests that the radical scavenging antioxidant should be converted to other stable nonradical compounds during the reaction. This method requires only a simple HPLC instrument, and the disappearance or decrease in the peak intensity, which is induced by the addition of DPPH. This change is monitored by the HPLC to detect the powerful radical scavenger from the complex mixture. The method was applied to the detection and identification of the most powerful antiradical compound in the extracts of three antioxidatively active plant extracts (Psidium guajava, Citrus depressa, and Hypericum chinense). The radical scavenging efficiency of a newly identified compound from H. chinense was also compared with that of Trolox and catechin using the method.     

土壤碳水化合物的转化与累积研究进展

碳水化合物虽然仅占土壤有机质的10%~20%,却是土壤中最活跃的有机碳库,是微生物的主要能源和碳源,并参与土壤团聚体的形成,是土壤有机质和土壤性质研究中的重要指标和对象。本文综述了土壤碳水化合物种类、来源和在团聚体中的分布特征、微生物群落结构对碳水化合物的转化和积聚的影响,同时讨论了耕作、施肥等农业措施对碳水化合物含量和分布的影响。从现有文献资料来看,碳水化合物的含量因土壤粒级不同而异;外源碳水化合物在土壤中的转化和累积与微生物群落结构特征密切相关,细菌在单糖等简单碳水化合物的转化中起主要作用,而复杂碳水化合物则首先在真菌的作用下水解成单糖;真菌和革兰氏阳性菌丰富的土壤更有利于碳水化合物来源碳的累积,但是详细的转化过程和存在形态认识有限,有待深入研究。     

Study of Three-Dimensional Structure of Wheat Starch Granules Stained with Remazolbrilliant Blue Dye and Extracted with Aqueous Sodium Dodecyl Sulfate and Mercaptoethanol Solution

Wheat starch granules were obtained from soft wheat flour by acetic acid fractionation (pH 3.5), and the starch was stained by reaction with Remazolbrilliant blue (RBB) dye. RBB-stained starch was extracted with 1% sodium dodecyl sulfate (SDS) and 1% 2-mercaptoethanol (ME) for 14.5 hr at room temperature. This extraction step was repeated five times (extracts 1–5). SDS-ME extracts were subjected to size-exclusion column chromatography, and comparisons of their profiles for specific absorbance at 650 nm (A₆₅₀) and carbohydrates were made. After high molecular weight (HMW) carbohydrates on the starch granule surface were extracted, HMW carbohydrates inside the granule appeared to be extracted. Finally, low molecular weight (LMW) carbohydrates near the granule surface were extracted. Phase-contrast light microscopy of the treated starch granules showed that all granules became transparent. Two different interior structures were observed. Scanning electron microscopy indicated that the granule was split into two parts at the equatorial groove. The interior of the granule showed two different areas: a central hole area and the surrounding stratified area. Extraction beyond five times with the same solvent dissolved the weak part of the granule structure and left two types of skeletal structures. The appearance of the skeletal structure of the granule surface was different from the appearance of interior structures.     

Preparation of 2H-furo[2,3-c]pyran-2-one derivatives and evaluation of their germination-promoting activity

The butenolide, 3-methyl-2H-furo[2,3-c]pyran-2-one (1), has recently been identified as the germination stimulant present in smoke that promotes the germination of seeds from a wide range of plant species. In this paper, we describe the preparation of a number of analogues of 1 and compare their efficacy in promoting seed germination of three highly smoke-responsive plant species, Lactuca sativa L. cv. Grand Rapids (Asteraceae), Emmenanthe penduliflora Benth. (Hydrophyllaceae), and Solanum orbiculatum Poir. (Solanaceae). The results show that the methyl substituent at C-3 in 1 is important for germination-promoting activity while substitution at C-7 reduces activity. In contrast, bioactivity is mostly retained with analogues substituted at C-4 or C-5.     

Rapid screening of polar compounds in Brazilian propolis by high-temperature high-resolution gas chromatography-mass spectrometry

Methanol extracts of propolis from six different places, five in Rio de Janeiro state and one in S?o Paulo state, both in the Southeast of Brazil, were investigated using high-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC-mass spectometry. The main purpose of the study was to establish the applicability of HT-HRGC as an analytical method for systematic studies of polar propolis fractions. Several compounds, including carbohydrates, phenolic acid derivatives, and high molecular weight compounds (e.g., wax esters of long chain fatty alcohols) could be readily characterized in the crude extracts by HT-HRGC-MS. HT-HRGC and HT-HRGC-MS were shown to be quick and informative tools for rapid analysis of crude polar extracts without cleanup.     

Amperometric Biosensor Approaches for Quantification of Indole 3-Acetic Acid in Plant Stress Responses

Amperometric biosensors are known to be sensitive, reliable, and inexpensive instruments for biomolecular detection. Recently, self-referencing amperometric biosensors have been utilized to quantify the endogenous apoplastic flux of plant hormone indole 3-acetic acid (IAA) in vivo. There is still a significant need for sampling and testing methods to measure IAA concentrations in whole tissue samples. In the present study we used nanomaterial-modified platinum microelectrodes for the detection of IAA extracted from whole plant tissues. The key to the use of the nanomaterials was to enhance the surface area and thus the limit of detection for IAA. The nanoscale electrochemical interface was modified by the application of a layer of platinum black, followed by silanization overnight and a coating of multiwalled carbon nanotubes. Electroanalytical characterization of sensor performance was evaluated using both IAA standards and IAA extracted from corn plant samples, using a three-electrode scheme (reference, sensing, and auxillary). We compared tissue concentrations in water- and salt-stressed corn seedlings and compared these results to values measured using established enzyme-linked immunosorbent assay (ELISA) protocols. We found that the values obtained from both methods were comparable. The data obtained from the IAA sensor suggested that the electroanalytical biosensor approach was slightly more reliable and sensitive. Our results demonstrate a novel nanomaterial biosensor approach for IAA quantification in plant tissue extracts. The results of the stress study clearly indicated that root and shoot elongation and growth had significant positive correlation with IAA content in the raw plant tissue extracts. Water and salt stress both reduced root and shoot growth, which may be due to overaccumulation of IAA, resulting in inhibition of elongation. In comparison to established methods, such as high-performance liquid chromatography (HPLC) or ELISA, our approach is simple and inexpensive. Unlike HPLC, our approach does not require any elaborate sample purification, nor does it require antibody development as needed for ELISA. In summary, this electroanalytical biosensor method can be effectively utilized for simple, cheap, and reliable detection of IAA extracted from plant samples.     

Cell cytotoxicity and mycotoxin and secondary metabolite production by common penicillia on cheese agar

Known or potential new fungal starter culture species such as Penicillium camemberti, P. roqueforti, P. nalgiovense, P. caseifulvum, and P. solitum have been cultivated on a cheese agar medium together with the common cheese contaminants P. commune, P. crustosum, P. discolor, P. atramentosum, and P. nordicum. Secondary metabolites were extracted and analyzed by HPLC-DAD and tested for cytotoxicity by using the MTT-cell culture assay. Metabolites such as cyclopiazonic acid, roquefortine C, and penitrem A, previously reported from cheese, were detected together with sclerotigenin, solistatin, meleagrin, oxaline, compactins, diaportins, chaetoglobosins, rugulovasines, verrucolones, anacines, verrucines, cyclopeptines, viridicatins, and viridic acid, all metabolites not previously reported from cheese. The two P. nalgiovense extracts were the most toxic in the MTT-cell culture test. These extracts contained diaportines together with a number of unknown compounds. P. roqueforti extracts were not toxic at all. Fungal extracts from the rest of the studied penicillia were toxic at levels between these two extremes.