The ecology of heterogeneity: soil bacterial communities and C dynamics

<p>Heterogeneity is a fundamental property of soil that is often overlooked in microbial ecology. Although it is generally accepted that the heterogeneity of soil underpins the emergence and maintenance of microbial diversity, the profound and far-reaching consequences that heterogeneity can have on many aspects of microbial ecology and activity have yet to be fully apprehended and have not been fully integrated into our understanding of microbial functioning.</p><p>Heterogeneity in soils has multiple facets, from the molecular heterogeneity of the diversity of substrate available, the activity heterogeneity due to the activity of microbial species and the spatial heterogeneity of the soil structure and the distribution of organisms.</p><p>In this contribution we present a simple, spatially explicit model that can be used to understand how the interactions between the heterogeneity of decomposers (in terms of species and spatial distribution) and environmental heterogeneity (in terms of the diversity of substrates and their spatial distribution) affect the bacterial decomposition of organic matter. We found that environmental heterogeneity is a key element in determining the variability of the decomposition process.</p>

ISOLATION OF Salmonella typhoid 16s rRNA GENE FRAGMENT BASED ON POLYMERASE CHAIN REACTION (PCR)

Iridescent is one of the traditional fish fermentation products that has a sour taste and is widely known in various regions of Indonesia. In its metabolism LAB produces organic acids, hydrogen peroxide, diacetyl, CO2 and bacteriocin. These compounds are antimicrobial compounds that inhibit the growth of pathogenic bacteria and bacterial decomposition. The purpose of this study was to determine the antibacterial activity produced by lactic acid bacteria isolates from catfish (Pangasius hypophthalmus) inhibiting the growth of Escherecia coli. From iridescent obtained 9 isolates that have different characteristics from each other by the morphology of LAB isolate colonies which include colony color, colony shape, colony elevation and colony margin. After production of antibacterial, all isolates showed positive result when antibacterial tested againts Escherecia coli either in acidic condition or neutralized.

Investigation of sorption of 2,4-dichlorophenol on special hungarian oil shale

The development of efficient methods for the removal of different type of organic contaminates of natural waters is an ever challenging task in the modern environmental technology. The paper reports the physical characterization and adsorption properties of a Hungarian oil shale. Static equilibrium experiments were carried out to study the adsorption of 2,4-dichlorophenol from aqueous solution. The obtained equilibrium data were satisfactorily fitted by a multistep adsorption isotherm within the concentration range of 0 to 100 mg/l. According to our laboratory scale experiments the studied adsorbent immobilizes the contaminants more efficiently than a number of other adsorbents applied in different remediation technologies. More than 90 % of the added 2,4-dichlorophenol was adsorbed by the studied oil shale. The contaminants are bound strongly by the sorbent therefore they cannot be washed out by the groundwater flow which, in turn, favors to the natural bacterial decomposition process of the polluting compound. This is considered as a significant advantage of the adsorbent because no chemical regeneration of the inexpensive oil shale is required. The reported results indicate that the oil shale can be used efficiently for the treatment of natural waters to remove their organic contaminants.

Oxygen depletion in subarctic peatland thaw lakes

Permafrost thawing and erosion results in the enrichment of northern lakes by soil organic matter. These allochthonous inputs favour bacterial decomposition and may cause the draw-down of dissolved oxygen to anoxic conditions that promote methanogenesis. Our objective in the present study was to determine the seasonal variations in dissolved oxygen in a set of permafrost peatland lakes in subarctic Quebec, Canada, and to relate these changes to metabolic rates, ice cover, and mixing. The lakes had high dissolved organic carbon concentrations, and their surface waters in summer had greenhouse gas concentrations that were up to one (CO2) to three (CH4) orders of magnitude above air-equilibrium values, indicating their strongly heterotrophic character. Consistent with these observations, the peatland lakes had elevated rates of bacterial production and oxygen consumption. Continuous measurements of oxygen by in situ sensors and of ice cover by automated field cameras showed that the lakes became fully anoxic shortly after freeze-up. The waters were partially re-oxygenated by mixing events in spring and fall, but in one lake, the bottom waters remained anoxic throughout the year. These observations provide a foundation for subsequent biogeochemical and modelling studies of peatland thaw lakes as an abundant class of Arctic freshwater ecosystems.

Odontometrics: A Key to Gender Determination

ABSTRACT Introduction Identification of an individual is a prerequisite for certification of death and for personal, social, and legal reasons. Sex determination is one of the important parameters in forensic identification. Tooth being strongest component can resist bacterial decomposition and fire when rest of the body is damaged beyond recognition. Sexual dimorphism refers to the systemic difference in the form between individuals of different sexes within the same species. Teeth of various species are known to exhibit sexual dimorphism. The present study aims to evaluate the linear dimensions of permanent molars and canines for sex determination and to estimate their level of accuracy. Materials and methods Sixty subjects were included in the study. Study casts were prepared and the dimensions of permanent canines and first permanent molars were measured as the greatest distance between the buccal and lingual surface as well as mesial and distal aspects of the crown by using digital vernier callipers. Results Discriminant function analysis had shown that males have greater mean mesio-distal (MD) and bucco lingual (BL)/ labio-lingual (LL) dimensions for each tooth in comparison to females. Right upper canine showed the maximum accuracy followed by right lower and left upper canines. Out of four molars, right lower molar showed maximum accuracy of 86.7%. Conclusion The present study showed the importance of linear dimensions of canines and molars in the assessment of sex and molars can be used as an alternative to canines when their evidence is missing in forensic investigations. How to cite this article Dalli DT, Reddy S, Dathar S, Nallakunta R, Madugula P, Darna G. Odontometrics: A Key to Gender Determination. World J Dent 2016;7(3):150-154.

Composition of soil nematode communities in native birch forests in Central Europe

Soil nematodes were studied in 27 birch forests in the Slovak and Czech Republics. A total of 66 nematode genera were found. The eudominant nematode genera were Rhabditis and Aphelenchoides, followed by dominant genera Cephalobus, Paratylenchus, Plectus, Helicotylenchus and Aglenchus. Nevertheless, only Rhabditis, Cephalobus, Plectus and Aphelenchoides were recorded in all investigated birch stands. The highest nematode abundance was recorded in the birch forest situated in the Drahanská Highland (the Czech Republic). All nematode trophic groups were present in the investigated birch forests, with bacteriovores being the dominant group, followed by plant-parasitic nematodes, fungal feeders, root-fungal feeders, omnivores and predators. Ecological evaluation of nematode communities based on ecological indices demonstrated that the conditions of the nematode communities in birch forests were rather stable with prevailing bacterial decomposition pathways, which reflects the dominance of bacteriovorous nematodes.