Application of dendrogeomorphology on the study of soil sediment deposition in the stems of Guarea guidonea trees in a disturbed riparian forest in Goias state, Brazil

The sediments resulting of natural or anthropic erosion are deposited on the soil surface and around the trunks of trees occurring in riparian forests. For assessment of the erosion, tree-rings of roots and stems were analyzed. Guarea guidonea trees from a riparian forest affected by the sedimentation of soil erosion from pastures and soybean fields in state of Goias were selected. Wood samples were extracted through a non-destructive method at three heights from trunks of trees located in three positions (top, middle and bottom) of a riparian slope. The evaluation revealed a deposition of a thick sediment layer up to 34 cm around the base of tree trunks during the past 24 years. The inter-correlations between the tree-rings widths present in wood samples at the base and at 50 and 100 cm from Guarea guidonea tree trunks presented low, medium and high values. These values resulted from the low tree-rings distinctiveness in the wood; the absence of some rings as well as the eccentricity of the pith. The analyses of dendrogeomorphology allowed the determination of the date of seed germination and tree growth and inference on the periods of sediment deposition in the trunk of the trees.

Morphology and Anatomy of Stem Mines in Cipocereus minensis (Wender.) Ritter (Cactaceae), an Endemic Species to Eastern Brazil

Plant mines are structures with the form of a cavity caused by consumption of host plant tissue by the insect's miner larvae. Plant mines are more common in leaves, but in Cipocereus minensis, a species in which the leaves are modified spines, the miner activity is restricted to the stem. The aim of this paper was to document the morphological and anatomical differences in the infected and uninfected stems of C. minensis due to the feeding habit of the mining agent. Fresh tissue samples of non-mined and mined young stem of C minensis were collected and examined in transverse sections. We hypothesize that the infection begins following mating when the females scratch the surface of the stem or while they feed on fruits and lay eggs, which subsequently develop into larvae, invading the cactus stem. The insect's miner larvae had mostly consumed the parenchyma tissue towards the center of the stem, and periderm formed along the entire path of the insect. This meristematic tissue or "wound periderm" is a common response for compartmentalization to isolate the damaged tissue, in this case the incubating chamber, in which the eggs will be placed. There were no signs of consumption of vascular tissue in the infested samples, further suggesting a compartmentalized infestation. The nest chamber was found in the stem pith region, with periderm surrounding an insect's miner pupa inside identified as a member of the Cerambycidae. The mining insect depends on a host plant to complete the life cycle; however, the nature of this partnership and the long-term effects of the insect on the plant tissue are unknown. The complex mechanisms by which herbivorous insects control the morphogenesis of the plant host are discussed. We propose that C. minensis has a recognition system to identify insect attack and evaluate the effectiveness of early response triggering compartmentalized defense mechanisms by protecting the injured area with a new layer of periderm.

Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

Influence of processing conditions on quality aspects of potato-based fresh pasta

Gnocchi is a typical Italian potato-based fresh pasta that can be either homemade or industrially manufactured. The homemade traditional product is consumed fresh on the day it is produced, whereas the industrially manufactured one is vacuum-packed in polyethylene and usually stored at refrigerated conditions. At industrial level, most kinds of gnocchi are usually produced by using some potato derivatives (i.e. flakes, dehydrated products or flour) to which soft wheat flour, salt, some emulsifiers and aromas are added. Recently, a novel type of gnocchi emerged on the Italian pasta market, since it would be as much similar as possible to the traditional homemade one. It is industrially produced from fresh potatoes as main ingredient and soft wheat flour, pasteurized liquid eggs and salt, moreover this product undergoes steam cooking and mashing industrial treatments. Neither preservatives nor emulsifiers are included in the recipe. The main aim of this work was to get inside the industrial manufacture of gnocchi, in order to improve the quality characteristics of the final product, by the study of the main steps of the production, starting from the raw and steam cooked tubers, through the semi-finished materials, such as the potato puree and the formulated dough. For this purpose the investigation of the enzymatic activity of the raw and steam cooked potatoes, the main characteristics of the puree (colour, texture and starch), the interaction among ingredients of differently formulated doughs and the basic quality aspects of the final product have been performed. Results obtained in this work indicated that steam cooking influenced the analysed enzymes (Pectin methylesterase and α- and β-amylases) in different tissues of the tuber. PME resulted still active in the cortex, it therefore may affect the texture of cooked potatoes to be used as main ingredient in the production of gnocchi. Starch degrading enzymes (α- and β-amylases) were inactivated both in the cortex and in the pith of the tuber. The study performed on the potato puree showed that, between the two analysed samples, the product which employed dual lower pressure treatments seemed to be the most suitable to the production of gnocchi, in terms of its better physicochemical and textural properties. It did not evidence aggregation phenomena responsible of hard lumps, which may occur in this kind of semi-finished product. The textural properties of gnocchi doughs were not influenced by the different formulation as expected. Among the ingredients involved in the preparation of the different samples, soft wheat flour seemed to be the most crucial in affecting the quality features of gnocchi doughs. As a consequence of the interactive effect of the ingredients on the physicochemical and textural characteristics of the different doughs, a uniform and well-defined split-up among samples was not obtained. In the comparison of different kinds of gnocchi, the optimal physicochemical and textural properties were detected in the sample made with fresh tubers. This was probably caused not only by the use of fresh steam cooked potatoes, but also by the pasteurized liquid eggs and by the absence of any kind of emulsifier, additive or preserving substance.

Proceedings of the Seventh Annual Biochemical Engineering Symposium

This is the seventh in a series of symposia devoted to talks by students on their biochemical engineering research. The first four meetings were held alternately at Kansas State University and the University of Nebraska–Lincoln, with participants from those two schools. The next two took place at Kansas State and then in conjunction with the 8lst American Institute of Chemical Engineers National Meeting in Kansas City, with attendees from Kansas State and Iowa State Universities. This meeting, at Iowa State, was the first to include participation from the University of Missouri–Columbia. Contents"Properties of Soluble and In:anoblized Dextransucrase," Hossein Kaboli and Yah Eric Chen, Iowa State University "Growth of Lipid-Producing Organisms on Formic and Acetic Acid-Containing Waste Waters," Lin-Chang Chiang, University of Missouri–Columbia "Design of an Automated Alkaline Copper Reducing Sugar Assay," Alfred R. Fratzke and James R. Frederick, Iowa State University "Determination of Oxygen Transfer Coefficients in Hydrocarbon Fermentations Using a Material Balance Method," Sarafin N. Sanchez and J. R. Gutierrez, Kansas State University "Oxygen Transfer Characteristics in One Stage and Two Stage Air-Lift Towers," Mark E. Orazem, Kansas State University "A Comparison of Biological Digestibility Tests for Cellulose," Dou-Houng Hwang, University of Missouri–Columbia "Mechanism of Enzymatic Hydrolysis of Cellulose," L. T. Fan, Yong-Hyun Lee, and Liang-Shih Fan, Kansas State University "Purification of Xylan-Hydrolyzing Enzymes," James R. Frederick, Alfred R. Fratzke, and Mary M. Frederick, Iowa State University "Cellulase Production from Bagasse and Pith," A. Ferrer, Y. Alroy, and I. Brito, Kansas State University