Spent mushroom substrates as component of growing media for germination and growth of horticultural plants

This research work was conducted in order to investigate the possibility of using spent mushroom substrate (SMS) in the production of horticultural seedlings replacing part of the peat in the growing media. Three vegetable species with different salt sensitivities, the less sensitive being tomato (Lycopersicon esculentum var. Muchamiel), the moderately salt-sensitive being courgette (Cucurbita pepo L. var. Afrodite F1) and the most salt-sensitive being pepper (Capsicum annum L. var. Lamuyo F1) were grown in 12 media containing SMS of two types of mushroom (Agaricus bisporus (SMS-AB) and Pleurotus ostreatus (SMS-PO)) or a mixture of both 50% (v/v) (SMS-50), as well as peat in various ratios. The proportions of each residue in the mixtures elaborated with peat were 25%, 50%, 75% and 100% v/v residue. A substrate of 100% peat was used as control. The experiment was arranged in a completely-randomised design with two replicates per treatment under greenhouse conditions. Prior to sowing, some physical, physico-chemical and chemical properties of the growing media were determined and seed germination and fresh weight of seedling were also measured. In most of the cases, the addition of SMS to the growing media produced an increase in the pH values, salt contents, macro and micronutrient concentrations and a decrease in the water holding capacity contents in comparison to peat, whereas great differences were found in the air capacity values between SMS-based substrates and peat. Up to 75% SMS can be used in mixtures with peat for seed germination of the plant species studied. Regarding the most suitable SMS-based substrates for plant growth, any substrate could be used for tomato seedling production. However, all SMS-AB-based substrates and the media containing low dose of SMS-PO and SMS-50 were adequate for growth of courgette and pepper.     

Evaluation of edible mushroom Oudemansiella canarii cultivation on different lignocellulosic substrates

In this study, the mycelial growth rate, mycelial colonization time, yield, and biological efficiency of the edible mushroom Oudemansiella canarii were determined, and the effects of different substrate combinations on productivity, chemical contents and amino acids were evaluated. Lignocellulosic wastes, such as cottonseed hull, sawdust, corncob, and their combinations supplemented with 18% wheat bran and 2% lime, were used for the cultivation of O. canarii. The biological efficiency (BE) and essential amino acid content of treatment T1, which consisted of 80% cottonseed hull, were the highest among all the tested treatments. Mixtures that included sawdust, such as treatments T2 (80% sawdust), T4 (40% sawdust + 40% cottonseed hull), and T6 (40% sawdust + 40% corncob), exhibited lower yield and BE. Corncob was good for O. canarii production in terms of yield and BE, whereas the mycelial growth rate and colonization time were lower compared to those on other substrates. Comparing the BE, essential amino acids, and other traits of the six treatments, treatment T1 (80% cottonseed hull) was the best formula for O. canarii cultivation and should be extended in the future.     

Ligand binding analysis and screening by chemical denaturation shift

The identification of small molecule ligands is an important first step in drug development, especially drugs that target proteins with no intrinsic activity. Toward this goal, it is important to have access to technologies that are able to measure binding affinities for a large number of potential ligands in a fast and accurate way. Because ligand binding stabilizes the protein structure in a manner dependent on concentration and binding affinity, the magnitude of the protein stabilization effect elicited by binding can be used to identify and characterize ligands. For example, the shift in protein denaturation temperature (T_m shift) has become a popular approach to identify potential ligands. However, T_m shifts cannot be readily transformed into binding affinities, and the ligand rank order obtained at denaturation temperatures (?60 °C) does not necessarily coincide with the rank order at physiological temperature. An alternative approach is the use of chemical denaturation, which can be implemented at any temperature. Chemical denaturation shifts allow accurate determination of binding affinities with a surprisingly wide dynamic range (high micromolar to sub nanomolar) and in situations where binding changes the cooperativity of the unfolding transition. In this article, we develop the basic analytical equations and provide several experimental examples.     

Studies on habitat selection by amphipods using artificial substrates within an estuarine environment

Field studies on habitat selection and community development of four gammarid amphipod species were conducted in a brackish lagoon at Nanakita River Estuary, Japan. Development of amphipod community was studied by focussing mainly on provision of shelter for these invertebrates. Seven artificial substrates (including wire net cage, circular concrete block, dried oyster shell, brush, sponge, blue and green tapes) were used in the field as substitutes of natural substrates (macroalgae). This paper demonstrates that amphipods will mostly select and inhabit substrates with available space that provide them with adequate protection. Brush substrate was ranked the best among the selected substrates, because its filamentous nature like natural substrates (macroalgae) provided suitable habitat for both tube-dwelling and free-living amphipods and accommodated maximum densities of amphipods in all seasons at all stations. Tube-dwelling amphipods (domicolous) constructed their tubes in and on algal substrates and their densities tended to be correlated with algal biomass, whilst free-living species (nestlers) prowled on surfaces, clang to filamentous structures and hid themselves in crevices, holes and boulders. Brush substrates at different stations suggested the importance of site difference.     

Towards molecular computing: co-development of microfluidic devices and chemical reaction media

Microfluidics provides a powerful technology for both the production of molecular computing components and for the implementation of molecular computing architectures. The potential commercial applications of microfluidics drive rapid progress in this field-but at the same time focus interest on materials that are compatible with physiological aqueous conditions. For engineering applications that consider a broader range of physico-chemical conditions the narrow set of established materials for microfluidics can be a challenge. As a consequence of the large surface to volume ratio inherent in microfluidic technology the material of the device can greatly affect the chemistry in the channels of the device. In practice it is necessary to co-develop the chemical medium to be used in the device together with the microfluidic devices. We describe this process for a molecular computing architecture that makes use of excitable lipid-coated droplets of Belousov-Zhabotinsky reaction medium as its active processing components. We identify fluoropolymers with low melting temperature as a suitable substrate for microfluidics to be used in conjunction with Belousov-Zhabotinsky droplets in decane.     

Use of Ranks in Comparisons of Variability in the Non-Normal Populations

A method of analysis for comparing the variability of two samples drawn from two populations has been developed. The method is also suitable for the nonnumeric form of data. A test based on ordered observations for testing the null hypothesis of equality of two variances has been given. The test statistic is a function of the sum of ranks assigned to smaller size sample. Ranking procedure has been modified to depict the variability in the data by the sum of ranks. The null distribution of the test-statistic has been worked out for small samples and it turns out to be chi-square distribution for large samples. The analytical procedure has been explained by a numerical example on the productivity and production of rice and wheat in India from 1950–51 to 1983–84.     

Assessing the short-term response of stream diatoms to acidity using inter-basin transplantations and chemical diffusing substrates

1. Acid‐base status has major effects on diatoms, but there is little information on their short‐term response to changing acidity. This is despite the use of diatoms as bioindicators in streams where acid episodes are important during rainstorms (hours to days) or snowmelt (days to weeks). In the Llyn Brianne experimental catchments (Wales, UK), we attempted to mimic the effects of short‐term acidification by (i) reciprocally transplanting diatoms between two streams of contrasting acidity and (ii) using acid‐diffusing substrates. 2. Diatom diversity decreased rapidly on substrata transplanted from the circumneutral into the acidic stream, and increased in the reciprocal transplantation. Changes in dominant taxa occurred within three days in the acidic stream because of the rapid growth of Eunotia exigua, and by nine days in the circumneutral stream because of the proliferation of Achnanthidium minutissimum. Transplants were near indistinguishable from ambient assemblages by day 12. 3. There were no effects of enclosures on assemblage composition, but diatoms responded more rapidly to altered chemistry in enclosures with coarse mesh (26 × 50 mm) than finer mesh (320 μm). 4. Chemical diffusing substrates comprised terracotta tiles attached to dosing reservoirs that created locally acid (using H₂SO₄) or metal‐rich conditions (using MnSO₄) in the circumneutral stream over 26 days. Diatom responses were compared with reference substrates dosed with deionised or circumneutral stream water, and we also assessed whether effects were moderated by macroinvertebrate grazers. 5. Surface pH was lower by 1–2 pH units on acid‐dosed substrates than on reference tiles or in surrounding streamwater. Grazed assemblages on acid‐dosed substrates differed significantly from ungrazed reference assemblages, acquiring significantly greater relative abundance of Eunotia spp. However, the magnitude of response was less than in the between‐stream transplantations either because (i) metal exposure and base cation concentrations differed between the transplants and dosing substrates or (ii) diatom response to reduced pH on the diffusing substrates was restricted by the scarcity of acidobiontic diatoms in the circumneutral stream. Similar filter, founder or dominance effects might also affect diatom responses to real acid episodes. 6. These data show that diatom assemblages can respond rapidly and directly to changes in acid‐base status, but short‐term acidification might affect diatoms more rapidly than subsequent recovery. Because the experimental methods used were imperfect representations of episodic effects, diatom response to real acid events requires further field evaluation.     

Evaluation of recombinant caspase specificity by competitive substrates

The specificity of 10 recombinant caspases was investigated using a set of competitive substrates. The caspase activity was determined by high-performance liquid chromatography using highly fluorescent peptides containing 2-aminoacridone (AMAC) as reporting group. The sequences of the used substrates were designed according to literature data for being specific for 10 of the caspases. The described approach allows the concentration changes of several substrates to be monitored simultaneously in a single sample. Because the substrates are in competitive conditions, the preferences of particular caspases to given peptide sequences are most clearly demonstrated. In the studied competitive assay conditions, all tested caspases except caspase 2 exhibit activity toward more than one substrate. None of the used peptide sequences was found to be highly specific for a defined caspase. The results obtained indicate that there is well-expressed group specificity among the caspases.     

Variability and genetics of tolerance for aluminum toxicity in rice (Oryza sativa L.)

A study was undertaken to investigate the variability among lowland rice cultivars and the mode of gene action of aluminum (Al) toxicity tolerance in rice. Pregerminated seeds were grown in a nutrient solution containing 30 ppm Al and in normal nutrient solution, and relative root length (RRL) was determined at the 14-day-old stage to characterize genotypes for tolerance. Sixty-two traditional rice cultivars grown on lowland acid sulfate soil areas of Asia and West Africa were tested. Tolerant varieties Azucena, IRAT104, and Moroberekan, moderately sensitive IR29 and IR43, and sensitive IR45 and IR1552 were used to investigate the genetics of tolerance by diallel analysis. Of the 62 cultivars tested, only 3 were found to be sensitive to A l toxicity. Among the tolerant cultivars identified, 11 (Siyam Kuning, Gudabang Putih, Siyam, Lemo, Khao Daeng, Siyamhalus, Bjm-12, Ketan, Seribu Gantang, Bayer Raden Rati, and Padi Kanji) were found to possess higher levels of tolerance than the improved tolerant upland cultivar IRAT104. Diallel analysis revealed that high RRL is governed by both additive and dominance effects with a preponderance of additive effects. The trait exhibited partial dominance, and one group of genes was detected. Heritability was high, and environmenal effects were low. Findings suggest that when breeding for A1 toxicity tolerance, selection can be made in early generations. The pedigree method of breeding would be suitable. Combining ability analysis revealed the importance of both general combining ability (GCA) and specific combining ability (SCA) in the genetics of A1 toxicity tolerance in rice. GCA was more prevalent than SCA. Tolerant parens Azucena, IRAT104, and Moroberekan were the best general combiners. The presence of reciprocal effects among crosses suggested the proper choice of parents in hybridization programs. Results indicated that Azucena, IRAT 104, and Moroberekan should be used as the female in crosses for A1 toxicity tolerance.     

Structure-functional analysis of interactions of terminal deoxynucleotidyl transferase with new non-nucleoside substrates

New non-nucleoside esters of phosphoric acid containing various hydrophobic groups, namely (1) N-(2-tripticencarbonyl)-4-aminobutyl; (2) 5-phenylsubstituted N-(2,4-dinitrophenyl)-4-aminobutyl; (3) N-(4-phenylbenzoyl)- and N-(4-(N-benzylamino)benzoyl)-2-aminoethyl groups, as well as (4) diphenylmethyl and fluorenyl groups were synthesized and studied as substrates of terminal deoxynucleotidyl transferase. With the exception of the two latter derivatives, all the analogues displayed substrate properties and could incorporate into the deoxyoligonucleotide 3′-end. As it was shown in biochemical experiments and by computer modeling, a linker joining the triphosphate and hydrophobic fragments of the molecule was necessary for these compounds to display substrate properties.     

Agar as a gelling agent: chemical and physical analysis

Agars with different performance in bioassays were analysed for physical and chemical properties. Agars with the highest gel strength had the best performance. Good performance was also related to a low pH of a suspension of agars and to a low sulphur content. The diffusion rate of ions in gels differed between agars, but could not explain differences in agar performance. The time of autoclaving had a marked effect on the gel strength, however, without affecting the performance. Chemical analysis revealed large differences between agars. The best agars had a relatively low salt content. One of the best agars had an extremely high content of trace elements. Agar impurities, especially of the trace elements were tightly bound to the agars. Up to 30% of the Murashige and Skoog (MS) salts were also immobilized in the gel. At pH 4.2, less nitrogen and phosphate were available from the MS medium than at pH 5.7. Chlorine could be washed out completely and appeared to be a good marker for agar quality and purity. With AgNO₃, chlorine contamination could easily be visualized. Received: 28 April 1996 / Revision received: 15 December 1996 / Accepted: 20 January 1997     

Substrate size selectivity of 20S proteasomes: analysis with variable-sized synthetic substrates

Proteasomes are tubular complexes with proteolytic activities on their lumenal surfaces so that large substrates should be sterically hindered from reaching the catalytic sites. Here we examine effects of substrate size on rates of cleavage by 20S proteasomes of Methanosarcina thermophila. Synthetic chromogenic substrates of variable size were prepared by linking a constant substrate group (Ala-Ala-Phe-p-nitroanilide) to a linear polymer (methoxypolyethylene glycol) with variable chain length. The smallest macromolecular substrates were cleaved more efficiently than free tripeptide substrate, and cleavage of macromolecular substrates was saturable, whereas cleavage of free tripeptide substrate was not, indicating mechanistic differences between the cleavage of large and small substrates. Rates of macromolecular substrate cleavage decreased progressively up to 10-fold as the size of the polymeric component of substrates increased. Macromolecular synthetic substrates appear to be better models of proteasome action on natural protein substrates and demonstrate substrate size selectivity of proteasomes.     

Detection of l-alanylaminopeptidase activity in microorganisms using chromogenic self-immolative enzyme substrates

Three potential chromogenic enzymatic probes, each possessing a self-immolative spacer unit, were synthesised for the purpose of detecting l-alanylaminopeptidase activity in microorganisms. An Alizarin-based probe was the most effective, allowing several species to generate strongly coloured colonies in the presence of metal ions.     

Variability of colonial morphology in benomyl-induced morphological mutants from Candida albicans

Abstract Colonies of Candida albicans wild-type strain 1001 were white and glossy, and this character was rather stably maintained. In contrast, 2 benomyl (methyl benzimidazole-2-yl-carbamate)-induced mutant strains, B17 and B14, that grew as long filamentous forms and displayed a rough-wrinkled colonial phenotype, switched to other colonial morphologies at significant frequencies. Clonal populations of B17 segregated smooth or sectored (rough/smooth) colonies at a frequency of 1.85%, when plated in nutrient-agar. Strains derived from these rough or smooth segregants switched back to one or the other phenotype at similar frequencies. Colonial variability in C. albicans B14 was not restricted to spontaneous switching from rough to smooth or vice versa, but eventually other types of variants, characterized as 'wavy' and 'fuzzy' were obtained, and shown to have their own capacity to switch. Smooth variants, derived from B14, were essentiallt unicellular, whereas fuzzy strains consisted only of long thin filaments, wavy and rough clones apparently being intermediate in their degree of filamentation. It is concluded that the capacity for colonial variation shown to exist in natural isolates could be activated by benomyl in others, such as 1001, which are quite stable and do not switch colonial morphology spontaneously.     

An overview of animal cell substrates for biological products

The issue of which cells to use as substrates for the production of biological products, and especially vaccines, has been with us in one form or another ever since the development of cell cultures in the 1950s.The major cell substrate events that occurred over the past 50 years are reviewed briefly. Although numerous conferences were held during that period, incomplete resolution of some cell substrate issues has remained. Specifically, the potential oncogenicity of cellular DNA derived from continuous cell lines, and the tests that are used to rule out the presence of adventitious agents have been recognized as areas that could benefit greatly from studies using state-of-the-art techniques.A collaborative effort involving WHO, NIAID, and IABS resulted from consensus recommendations of a 2004 conference, and the prospects for revised guidance in the near future on the characterization and use of animal cell substrates are bright.     

Proficiencies of two artificial substrates in collecting stream macroinvertebrates

Proficiencies in collecting stream macroinvertebrates by two types of artificial substrates, #200 3M conservation webbing and cone-shaped concrete blocks, were compared with bottom net collections. Conservation webbing collected more individuals than cone substrates, but fewer taxa than either cone substrates or bottom nets. Diversity indices calculated for collections made with the three techniques were lowest for webbing collections, highest for net collections and intermediate for cone collections. It was concluded that collections made with webbing substrates gave an extremely distorted view of macroinvertebrate community balance due to a preponderance of net spinning and case building forms, and that cone substrates were better suited for use in the particular situation studied.Department of Biology, Virginia Polytechnic Institute and State University.Center for Environmental Studies, Virginia Polytechnic Institute and State University.     

A study of aspartyl proteases using intramolecularly quenched fluorogenic peptide substrates

A series of fluorogenic tetra-, penta-, and hexapeptide substrates of the general structure Abz-X-Phe-Phe-Y-Ded or (-pNa in place of -Ded), where X=Ala, Ala-Ala, or Val-Ala and Y=−, Ala, or Ala-Ala, were proposed. Kinetic parameters of hydrolysis of these substrates by pepsin, cathepsin D, human gastricsin, pig pepsin, calf chymosin, and aspergillopepsin A were determined. The compounds synthesized proved to be effective substrates for aspartyl proteases of diverse origins.     

Hydrology and substrates: determinants of oligochaete distribution in lowland streams (The Netherlands)

In most soft-bottomed, lowland streams in the Netherlands discharge regimes largely follow the precipitation pattern. Winter discharges are higher and much more dynamic then summer discharges, although rain storms throughout the year cause unexpected peak flows. Minimal precipitation, reduced stream flow and droughts can occur during the summer months. Lowland stream habitat, particularly in The Netherlands, is hydrologically dynamic, with substrates frequently moved or disturbed. Differences in discharge patterns in Dutch soft-bottomed lowland streams are expected to affect distribution patterns of macroinvertebrates and thus oligochaetes. Ten small to medium sized lowland streams, differing from one another in hydrological regime, were studied. Five major habitats in each stream were assessed on three occasions over a 15-month period. Each habitat sampled with a micro-macrofauna shovel; during each sampling period, several environmental parameters, especially hydrological and substrate parameters, were measured. Ordination (CANOCO) (Ter Braak, 1989) and statistical tests (chi-squared test) (Lindgren & McElrath, 1970) were used to determine the major oligochaete distribution patterns between streams as well as between habitats within each stream. Each stream was characterized by its oligochaete assemblage; general distribution patterns and individual oligochaete–substratum relationships were documented. Hydro-morphological parameters together explained the differences in major distribution patterns. Preferences of oligochaetes for specific structural habitats are discussed.