Volume 71, Issue 3

Among various strains of Bacillus subtilis , the strain RNZ-79 was selected for this study due to the highest uricase productivity in solid state cultures containing shrimp shell wastes, highest V max (0.42 μM mg −1 min −1 ) and lowest value of K m (56 μM). Maximum productivity was observed at pH 7.6 and 45°C with an inducer concentration of 0.4% (w/v) uric acid and moisture content of 80% (v/w). An inoculum of 7% (v/v) and particle size of 354–500 μm for substrate were optimal for productivity after 54 h of fermentation. None of the tested carbon and inorganic nitrogen sources had stimulatory effect on uricase productivity. KH 2 PO 4 at 0.12% (w/v) was the best source of phosphorus. Final uricase productivity was 5.05-fold more than the initial productivity. Enzyme purification increased the specific activity to 25-fold with a recovery of 36%. Furthermore, the purified enzyme showed a molecular mass of 33.7 kDa. Purified uricase was optimally active at pH 8.0 and 40°C and maximally stable at pH 7.0-10.0 and till 70°C for 30 min. The half-life ( t 1/2 ) at 60, 70, 80, 90 and 100°C were 87.0, 56.6, 30.0, 24.2 and 15.6 min, respectively, and the calculated midpoint temperature ( T m ) was 66.85°C. Interestingly, purified enzyme exhibited a good storage stability for 3 months and none of uric acid analogues were competitive inhibitor, indicating a high specificity of uricase.

Membrane biofouling is a common and emerging problem, where cells get cemented and create problems in industrial process. Frequent chemical cleaning used for the treatment of biofouled membrane shortens the membrane life time and creates ‘stress’ to existing microflora to trigger more exopolysaccharides production, which becomes the principle cause of biofouling. To understand safe and environmentally feasible antifouling strategies, key biofilm forming representative bacteria isolated from brackish and fresh water biofouled membranes were subjected to natural agents, such as vanillin (0.05–0.4 mg/mL) and salicylic acid (0.1–0.7 mg/mL). Salicylic acid (0.7 mg/mL) was found to be effective against only Pseudomonas group, whereas vanillin was remarkably potent against majority of the isolates because of structural mimicking with signalling autoinducer molecules. The present study showed that vanillin served as a good quorum quencher molecule as it inhibited 90% acyl homoserine lactones production at 0.3 mg/mL concentration in biosensor Chromobacterium violaceum CV026 strain and also inhibited 70% to > 90% biofilm formation in bacterial isolates. Biofilm formation and quorum sensing inhibition activities were validated by real-time quantitative PCR gene expression analysis in key representative membrane isolates. Vanillin served as antifouling natural agent towards broad spectrum community found on membranes.

This study was aimed to explore antibiofilm agents from the hitherto underexplored Palk Bay seawater bacteria. The cell free culture supernatant of the isolate Marinomonas sp. showed profound antibiofilm activity against Vibrio parahaemolyticus ATCC 17802. The active principle responsible for antibiofilm activity was identified as indole-3-carboxaldehyde (ICA) after bioassay guided purification and gas chromatography-mass spectrometry analysis. Further, in vitro antibiofilm activity of ICA was confirmed through light microscopy, confocal imaging, scanning electron microscopy and biofilm disruption studies. In addition, ICA efficiently reduced the swarming motility of the pathogen and promoted the swimming ability. Furthermore, the control of biofilms and swarming efficiency by quorum sensing pathway of the pathogen was modulated by ICA, which was substantiated using real-time analysis for opaR , cpsA , and lafA genes. This study divulged the efficacy of ICA as an antibiofilm agent against V. parahaemolyticus in vitro .

In this study, anti-infective potential of the medicinal plant Murraya koenigii was assessed through in vitro assays and microscopic analysis. The methanolic leaf extract of M. koenigii significantly inhibited the major virulence factors of Candida albicans , such as biofilm formation, yeast-to-hyphal transition, cell surface hydrophobicity, hemolysin production and filamentation. Further purification and molecular characterization of the active lead is expected to give a novel anticandidal agent for the treatment of Candida infection.

Media components were optimized using two-step statistical design of experiments for enhancing endoglucanase/ carboxymethyl cellulase (CMCase) production by Trichoderma reesei RUT C30. A Placket-Burman design identified cellulose concentration and pH as the most significant variables, which influenced the CMCase activity. Central composite design was employed to optimize these selected parameters. The optimal activity was obtained at cellulose concentration 19.7 g/L and pH of 7.2. Under the optimized conditions, CMCase activity was 83.63 ± 1.86 IU/mL and filter paper activity was 2.58 ± 0.2 filter paper units per mL. Enzyme productivity was higher compared to previous reports. The enzyme produced from T. reesei was concentrated and was evaluated for deinking of printed paper, which demonstrated the suitability of the enzyme for this application.

The suitability of the cyanolichen Peltigera praetextata (Sommerf.) Zopf as indicator of the effects of air pollution around a cement industry was investigated. For this purpose, lichen samples taken from an unpolluted site were exposed for 1–6 months at selected sites (a cement mill, two quarries, inhabited and agricultural sites) in SW Slovakia: physiological parameters and ultrastructural features were examined prior and after exposure. The responses of P. praetextata were then compared with those of the green-algal lichens Evernia prunastri and Xanthoria parietina co-located at the same sites. The performance of the cyanobacterial photobiont of P. praetextata (as reflected by the maximum quantum yield of primary photochemistry F V /F M and by the performance index PI ABS ) was negatively influenced mainly by the length of exposure in the urban and agricultural sites and less by dust pollution around the cement mill and the quarries. A significant increase in membrane lipid peroxidation products reflected the effects of oxidative stresses in all sites. The alteration of the content of water soluble proteins was detected in the samples exposed around the cement mill, while dehydrogenase activity did not show any significant pattern. Similarly to green algal lichens, ultrastructural alterations featured lipid droplets increase, swelling of cellular components, thylakoid degeneration and sometimes plasmolysis, which on the whole gave the cells an aged appearance, especially in the urban and agricultural sites. On the whole, E. prunastri confirmed to be the most sensitive to dust pollution, P. praetextata was likely influenced by microclimatic conditions and habitat eutrophication and X. parietina was the most resistant. When compared with green-algal lichens, P. praetextata was not the best indicator of the effects of cement dust pollution.

Lindernia dubia (L.) Pennell, a Northern-American species, was recently found in two localities in central Slovakia (near Trenč and Štiavnické Bane villages) as a new species for the flora of Slovakia. Individuals of the species grew in wetland vegetation of the class Isoëto-Nano-Juncetea in both cases. The second mentioned locality probably belongs to the altitudinal maxima of L. dubia in Europe. Although the origin of L. dubia in the Slovak localities remains unknown, we suppose that zoochory or anthropochory are the most probable modes of its introduction into the territory of Slovakia.

Data on seasonal variability in emergent macrophyte communities in regard to the composition of statistically significant indicator species remain incomplete. It was recognized by the authors as a potentially significant scientific issue and was defined as the main objective of this study. Information on the floristic composition of the communities included in this paper were collected in the Central Balkan Peninsula. Using a combination of cluster analysis and indicator species analysis, 11 emergent macrophyte communities were established. The seasonal dynamic of these communities did not include statistically significant modification of either the floristic composition or the species abundances according to the results of permutational multivariate analysis of variance (PERMANOVA). Nevertheless, seasonal variability in three communities –the Sparganium erectum community, Scirpus lacustris community and Typha angustifolia community – was registered in regard to the composition of their statistically significant indicator species. Disturbances primarily related to water level fluctuation in their habitats initiated a significant increase or decrease in the abundances of particular species. These slight structural changes were sufficient to induce a changeability in these communities in terms of the composition of their statistically significant indicator species over the growing season without a significant impact on the PERMANOVA results. This relatively “concealed” changeability of plant communities could have serious consequences on the processes of both defining and describing vegetation units because the indicator species are often used as “diagnostic species”. Consequently, future ecological studies should be more focused on investigating seasonal variability in diverse vegetation types in order extend our knowledge in this area.

To investigate the phylogenetic relationships among Kengyilia and related diploid genera, the genome donor of Kengyilia , and the evolutionary history of polyploid Kengyilia species, disrupted meiotic cDNA1 ( DMC1 ) sequences were analyzed for 11 Kengyilia species, together with 34 diploid taxa from 12 monogenomic genera. Sequence diversity and genealogical analysis suggested that (1) the St and P genomes were donated by Pseudoroegneria and Agropyron , respectively; (2) phylogenetic analyses separated the Y sequences from the St sequences, it confirmed that St and Y genome in Kengyilia species have originated from different donors; (3) the St genome of Kengyilia had several origins and diverse species of Pseudoroegneria might have taken part in the formation of polyploid species of Kengyilia .

Flax ( Linum usitatissimum L.) is the third largest natural fiber crop in the world. The flax genome shows environmentally induced heritable genomic changes. The activation of transposable elements has been proposed and identified as the mechanism behind this genotypic plasticity. Transposable elements, particularly the retrotransposons, generates genomic diversity by replication which makes them an excellent source of molecular markers. Inter-retrotransposon amplified polymorphism (IRAP) and the retrotransposon-microsatellite amplified polymorphism (REMAP) markers were used to assess the insertional polymorphism of LTR retrotransposons and genetic diversity in 80 genotypes of L. usitatissimum collected from Iran. A total of 77 and 133 loci were amplified using 7 IRAP and 13 REMAP primers, respectively. Percentage of polymorphic loci (PPL) for IRAP and REMAP markers were 53.25% and 58.92%, respectively. Average of expected heterozygosity (He), number of effective alleles (Ne) and Shannon’s information index (I) for IRAP markers were slightly more than those of REMAP markers. A high level of intra-population genetic differentiation was found, which is supported by a moderate level of gene flow among populations. A model-based Bayesian approach and cluster analysis using Minimum Evolution (ME) algorithm distinguished genotypes collected from Alborz region from those collected from Zagros region. Mantel test between genetic and geographical distances of populations revealed low but significant correlation coefficient (r = 0.36, P ≤ 0.05). The results demonstrated that molecular markers developed based on active LTR retrotransposons in flax could be used as relatively reliable tools to analysis population structure in L. usitatissimum .

The impact of different geographical regions (Silesian Foothills, region 1 and Maly Beskids, region 2), and method of soil use (arable field and grassland) on the main soil properties and biological activity was studied. Earthworm biomass, density and diversity, as well as dehydrogenase activity, were analysed. Significant soil physical and chemical properties were more affected by regions, whereas the type of land use had a greater impact on the biological properties. The mean earthworm density was 213 ind. m −2 and 241 ind. m −2 in grassland, and 50 ind. m −2 and 120 ind. m −2 in arable field, in region 1 and 2, respectively. Eight earthworm species were recorded, and fewer species were recorded in arable field (1–4) than in grassland (6–7). The Silesian Foothills are a new habitat for the occurrence of the speciesFitzingeria platyura depressa. A high earthworm density was accompanied by high microbial activity, and dehydrogenase activity was lower in the soil of arable field than in grassland soil.

A review of the family Perlohmanniidae Grandjean, 1954 (Acari: Oribatida) is provided with description of a new species: Perlohmannia (Perlohmannia) turcica from Turkey. Identification key to known species of the family is given. SEM images of the new species are also provided.

The feeding habits of two different populations of Perla pallida from two different streams in Armenia are described. Among Plecoptera, Perlidae have been particularly well studied regarding their feeding habits, but the trophic behaviour of this species all along its distribution area was neglected. This is the first information on the nymphal diet of this species. The aim of the present paper is to describe the feeding habits of P. pallida nymphs, to compare the obtained results between populations from the two streams and to compare the obtained data with those known in other Perla spp. Sixty nymphs from each stream, representing all the present size range, were selected to study the trophic habits by the transparency method. The percentage of various items and the number of prey was recorded. About 60% of the 120 analyzed nymphs had some gut content. The feeding habits of the studied populations of P. pallida in Armenia widely coincide with those observed in other Perla spp. populations all around Europe. The main trophic resources ingested by nymphs of these populations were animal matter (mainly Chironomidae and Ephemeroptera), detritus and diatoms. Significant negative correlations were found between head width and percentage of detritus in both populations. While detritus is an important component of the diet in smaller nymphs, we observed a significant trend to ingest higher size prey by bigger nymphs. Differences in the trophic spectrum width and statistically significant differences between populations were detected for the importance of some resources in the guts (such as detritus, diatoms and Chironomidae). We suppose that these differences reflect the taxonomical composition and abundance of aquatic macroinvertebrates assemblage and thus the quantity and composition of available prey at sampling stations, as well as differences in the availability of detritus and diatoms.

This study provides preliminary findings related to whether and how the roosting of starlings ( Sturnus vulgaris ) in reedbeds influences the survival of clutches of the great reed warbler ( Acrocephalus arundinaceus ). During the nesting seasons of 2014 and 2015, we surveyed the complete area of a mining pond in Serbia (south-eastern Europe) for great reed warbler nests, and the presence of roosting starlings was also recorded. Using the Mayfield method, we estimated the daily survival rate of great reed warbler eggs and nestlings, and compared these rates between starling roosting and non-roosting areas. Although both egg and nestling survival rates were lower in the Starling roosting than in the non-roosting areas, the differences were not significant, which was also reflected in overall nesting success. However, when only data from the time period when starling roosting occurred, the overall great reed warbler egg survival was significantly lower in roosting areas than in non-roosting areas. Our results suggest that Starling roosting did not influence the clutch survival of the great reed warbler significantly, but that there can be a negative short-term or local effect. Our study implies that a larger number of starlings and a longer roosting period could affect clutch survival more negatively.

There is not much data on the pathology of the hoof and of the distal phalanx in coldblooded horses (CH). In the present study we analysed the prevalence of certain abnormalities in hoof geometry and changes in the architecture and location of the distal phalanx related to those abnormalities in a randomly selected population of coldblooded horses. The study material comprised autopodium parts of forelimbs in CH from private animal farms ( n = 35). The analysis included the description and measurements of the hoof capsule, radiological assessment of the location of the distal phalanx against the dorsal wall of the hoof capsule and structure assessment of isolated distal phalanges. Numerous pathologies were observed in hoof capsules and distal phalanges in both forelimbs; there was no tendency for increased number of hoof pathologies in only one side of the body; exceedingly steep hoof was thrice more frequent than long-toe hoof; in 56% of the horses, ossification of the ungular cartilages (UC) was observed. The ossification was more frequent in the lateral cartilages and most distinct in the horses whose body weight exceeded 550 kg; it prevailed in the horses with steep hooves.

The mechanisms that allow species to evolve, coexist, compete, cooperate or become extinct are becoming always more understood. At the same time, the factors that allow species to coexist in a given time within the same environment are still debated. Many theories and hypotheses suggest that competition tends to differentiate the ecological requirements after repeated interactions and to allow the presence of many different species in the same area (i.e. biodiversity). After all, a thorough understanding of the evolutionary dynamics of biodiversity, which could somehow explain the current distribution patterns and mechanisms of coexistence, must consider the biogeographic and phylogenetic approaches. Here I propose a new graphic model that reviews the past and present, and sometimes debated, trends in biodiversity and evolutionary science, pointing out the importance of the avoidance of competition, the biological history, the endogenosymbiosis and the three-dimensionality as the main forces that structure ecosystems and allow the evolution of biological diversity. This model is an attempt to explain and summarize some of the mechanisms that underlie the current presence of the awesome number of species that currently inhabit our planet.