The decomposition of organic compounds in soil

Summary The course of the CO₂ evolution rates of soil samples has been followed continuously in the absence and in the presence of various organic compounds. After an incubation period of 300 hours at 13 and 20°C the CO₂ evolution from pasture soil (containing 1.76% soil organic carbon) amounted to 0.13 and 0.44g CO₂–C.g soil^–1.h^–1, respectively. For arable soil (containing 1.20% soil organic carbon) the rates amounted to 0.04 and 0.09 g CO₂–C.g soil^–1.h^–1, respectively.At 20°C larger amounts of the organic substrates added to the soil supplied with 20 g NH₄NO₃–N.g soil^–1 were lost as CO₂ than at 13°C, indicating a higher efficiency of the growth of microorganisms at lower temperatures. In the absence of NH₄NO₃ the respiration rates were initially higher than in its presence, suggesting that a part of the soil microflora is inhibited by low concentrations of NH₄NO₃. The amounts of carbon lost were low for phenolcarboxylic acids with OH groups in the ortho position. The replacement of one of these groups by a methoxyl group resulted in a larger amount of the C lost as CO₂. The replacement of the COOH group by a C=C–COOH group had a decreasing effect on the decomposition of the phenolic acids tested. The decomposition of vanillic acid,p-hydroxybenzoic acid, and of the benzoic acids with OH groups in the meta position was as complete as that of glucose, amino acids or casein. The decomposition of bacterial cells to CO₂ was considerably less than that of glucose.No evidence could be obtained that the low percentage of substrate converted to CO₂ at the time of maximal respiration rate was due to the decreasing diffusion rate of substrate to the microbial colonies in the soil during the consumption of substrate.     

Design,Synthesis, and Biological Evaluations of Novel Azothiazoles Based on Thioamide

Herein we studied the preparation of different thiazoles via the reaction of 2-(3,4-dimethoxybenzylidene)hydrazine-1-carbothioamide (1) with hydrazonoyl halides under base-catalyzed conditions. The reactions proceed through nucleophilic substitution attack at the halogen atom of the hydrazonoyl halides by the thiol nucleophile to form an S-alkylated intermediate. The latter intermediate undergoes cyclization by the loss of water to afford the final products. The structures of the azo compounds were confirmed by FTIR, MS, NMR, and elemental analyses. Indeed, the newly synthesized azo compounds were estimated for their potential anticancer activities by an MTT assay against different human cancer cells, such as lung adenocarcinoma (A549) and colorectal adenocarcinoma (DLD-1). The caspase-3 levels were also estimated using Western blotting and the dual staining technique to evaluate the potency of the titled compounds to promote apoptosis.     

Exploring Lassa Virus Proteome to Design a Multi-epitope Vaccine Through Immunoinformatics and Immune Simulation Analyses

International Journal of Peptide Research and Therapeutics - Lassa virus (LASV) is responsible for a type of acute viral haemorrhagic fever referred to as Lassa fever. Lack of adequate treatment...     

Mating behaviour and behavioural ecology of a Predatory Wasp,Symmorphus allobrogus (de Saussure) (Hymenoptera: Eumeninae)

This paper represents an attempt to investigate the mating behaviour of Symmorphus allobrogus, explaining the willingness of male to mount and copulate. The male displays including mode and frequency of antennation and position while copulating, the displays further comprises of intensity and frequency of rejecting behaviour. The presence of the male’s copulatory and postcopulatory courtship studies, understands the maintenance of monandry. The wasp has numerous secondary sexual characters, and the mating behaviour follows a phyletic and the specific sexual mating characters in context of sexual selection. The duration of mating phases and the number of male antennation series during precopulatory, copulatory and postcopulatory phases of mounting, differs significantly. Mating success depends mostly on the activities of male in the premounting phase and the behaviour of both sexes has a roughly equal importance for it in precopulatory phase. While during copulation, activity of male has little influence on its duration; however, behaviour of female has crucial effect, inducing its earlier termination.     

Influence of Magnetic Field on Brain Activity During Administration of Caffeine

The aim of the present work is to evaluate the effect of caffeine, the world’s most popular psychoactive drug, on the electric activity of the rat’s brain that exposed to extremely low-frequency magnetic field (ELF-MF), during 15 days. The obtained results showed that administration of caffeine in a group of rats by dose of 10 mg/kg (equivalent to human daily consumption) caused a reduction in the mean power amplitude of electroencephalogram (EEG) trace for almost all frequency bands especially α (8–12 Hz). It was observed that the influence of caffeine was more evident in motor cortex than in visual cortex. While the exposure of another group to ELF-MF of intensity 0.2 mT during the same period caused an enhancement in the mean power amplitude of most EEG frequency bands; this was more observed in the right hemisphere of the brain than that of the left hemisphere. The administration of caffeine while rats were exposed to ELF-MF, led, after 5 days of exposure, to a great increase in the mean power amplitude of α band at all places of recording electrodes. It may be concluded that caffeine administration was more effective in reducing the hazardous of ELF-MF in motor cortex than in visual cortex.     

Antioxidant, anticancer and hepatoprotective activities of Cotoneaster horizontalis Decne extract as well as α-tocopherol and amygdalin production from in vitro culture

The phytochemical analysis of the ethanolic extract of branches of Cotoneaster horizontalis, Decne revealed the presence of: β-carotene, ascorbic acid and less amounts of α-tocopherol and amygdalin (vitamin B₁₇) in proportions of: 2,500, 70, 0.093, 0.334 mg 100 g^?1, respectively. Acute oral toxicity test revealed its safety profile. In vitro study revealed its good 2, 2-diphenyl-1-picrylhydrazyl radical scavenging and anticancer activities. Invivo study, simultaneous administration of this extract at a dose of 100 or 200 mg kg^?1 body weight for 4 weeks, exhibited a significant protection in a dose-dependant manner against hepatotoxicity induced by repeated dose of acetaminophen (1 g kg^?1 body weight day^?1, p.o.) by preserving the liver function parameters, hepatic redox state and serum lipid profile near the healthy levels. Consequently, in vitro culture was carried out on full or half strength of Murashige and Skoog medium supplemented with different concentrations of benzyl amino purine or kinetin provided shootlets production; different concentrations of 2,4-dichlorophenoxy acetic acid and naphthalene acetic acid showed an increase of callus. Determination of α-tocopherol and amygdalin in different shootlets and callus extracts showed a pronounced increases up to 30.62 and 3.69 mg 100 g^?1 in shootlet extract, respectively as well as 26.61 and 12.71 mg 100 g^?1 in callus extract, respectively, as compared with those of the mother plant (0.76 and 0.11 mg 100 g^?1 extract, respectively).     

Chemical speciation and competitive cationic partitioning on a sandy aquifer material

Abstract

Coupled geochemical speciation/transport models are being developed to assess potential transport of metal contaminants in the subsurface environment. In a test of the geochemical speciation portion of the effort, MINTEQA2 model predictions are compared with laboratory data concerning the pH dependent partitioning behavior of eight cationic contaminants (Ba, Be, Cd, Cu, Ni, Pb, Tl and Zn) on a sandy aquifer material in an oxidized environment. MINTEQA2 contains provisions for describing potential attenuation due to both mineral phase precipitation processes and adsorption processes resulting from amorphous iron oxides in aquifer materials (MIT Diffuse Layer Model). In the comparison, several trends were discerned. (1) Adsorptive processes tend to better describe the pH-dependent partitioning behavior of transition metals (especially Pb, Zn and Ni). (2) Cd behavior is better described by precipitation as a cadmium carbonate phase. (3) Cu behavior is not reasonably described by the model. (4) Ba and Be comparisons are poor (although presumably their partitioning behavior results from adsorptive and/or pH sensitive solid solution processes). (5) unlike the other elements, the behavior of Tl is relatively insensitive to pH.