The interactions of model cationic drug with newly synthesized starch derivatives

Background and purpose The aim of the work was to compare the interactions of three newly synthesized non-toxic starch derivatives, with varied anionic and non-ionic functional groups with methylene blue (MB) as a model cationic drug, and selection of starch derivative with highest affinity to the MB. Experimental approach The native potato starch (SN), modified via acetylation (SM1), esterification and crosslinking (SM2) and crosslinking (SM3), was evaluated in MB adsorption studies and assessed by FTIR, PXRD, and DSC. Key results The adsorption of MB on SM2 and SM3 matched the BET isotherm model, which confirmed physisorption on the low-porous surface. In the case of SM1, adsorption took place via electrostatic attraction between the heterogeneous adsorbent surface and the adsorbate, as demonstrated by the Freundlich plot. The FTIR confirmed vibrations assigned to N=C stretching bonds at 1600 cm-1 in the case of MB adsorbed on the SN and SM2. The most intense PXRD peaks belonged to SN and the least to SM2. In the DSC study, the thermal stability via ΔT was assessed, with SM2 of lowest ΔT value (179.8 °C). Conclusion SM2 presented the best adsorption capacity, followed by SM3 and the weakest SM1. The interactions were confirmed in the adsorption studies and may reflect applications of the modified starches as drug carriers. In the FTIR study, a probable interaction between the OH- groups of SM2 and N+ of MB was revealed. The most amorphous structure was shown for SM2, which was correlated with the lowest thermal stability provided by the DSC study

Genetic identification of alien larch taxa : the case of the Tatra National Park

The natural consequences of introducing alien species can be significant. This is particularly a concern where the taxa have an invasive nature of spreading or in those that freely crossbreed with native species. The hybridization process may lead to impoverishment or even loss of the native gene pool. This is especially dangerous in unique areas that stand out due to their special natural characteristics, such as the Tatra National Park. The determination of the scale of occurrence of alien larch species in the national park and the evaluation of the genetic diversity of the native population is crucial for the conservation of genetic resources and strictly adheres to the latest conservation genetics trends. We evaluated the possibility of effective use of molecular markers for taxonomic identification of the native European larch (Larix decidua Mill.), as well as the alien Japanese larch (Larix kaempferi [Lambert] Carriere) and the hybrid form (Larix × eurolepis Henry). Microsatellite markers were used to analyse the genetic diversity of individuals identified as European larch from natural refuges and artificial plantings. Of the 148 trees analysed, 105 were identified as the European larch, 38 as Japanese larch, and five as hybrids. The analysis of the molecular variability of two European larch groups of indigenous and artificial origin showed comparable level of diversity. This study confirmed the effectiveness of the use of selected molecular markers in identification of larch species, which is difficult based on morphological traits. The results indicate the possibility for the effective use of genetic tools in the creation of protection programmes, especially for naturally valuable sites, based on genetic taxonomic identification and richness verification of protected gene pools

A modified method for molecular identification of Baylisascaris transfuga in European brown bears (Ursus arctos)

Baylisascaris transfuga is a roundworm that has been reported worldwide in most bear species. In mammals and possibly humans, the larvae of B. transfuga can migrate in the tissues of aberrant hosts with larva migrans syndrome. The current study was performed to identify B. transfuga in faecal samples from free-ranging brown bears in the Tatra Mountains National Park in southern Poland. A commercial kit was used to extract genomic DNA directly from faecal samples. Additionally, a Chelex resin-based technique was successfully implemented to prepare a PCR template from eggs retrieved by flotation. Based on the flotation results of 32 collected faecal samples, the prevalence of B. transfuga was 15.6%. The parasite was confirmed in samples found to be positive during the initial flotation by a molecular assay using DNA isolated directly from faeces. The retrieved eggs were confirmed as B. transfuga after their DNA was extracted using the Chelex protocol. Based on PCR amplification and sequencing of a 413-bp segment of cytochrome c oxidase 1 (COI), the obtained sequence was 100% identical to the COI segment of B. transfuga after a BLAST comparison to the GenBank™ database. The current study includes the first molecular confirmation of B. transfuga in brown bears in the western part of the Carpathians. We show that direct extraction of parasite DNA from bear faeces is efficient for molecular assays. As an alternative, we present the effectiveness of a Chelex-based technique for fast and convenient DNA isolation from the difficult-to-disrupt eggs of B. transfuga for PCR. Molecular tests of parasite DNA extracted directly from faecal material have limits of detection related to the amount of eggs in the samples. Thus, using classical flotation to obtain eggs for PCR may increase the credibility of the results, particularly in cases with a low number of excreted eggs. The Chelex resin protocol has potential for application in studies of intestinal parasites in wildlife for which conventional flotation is routinely used for microscopy

A modified method for molecular identification of Baylisascaris transfuga in European brown bears (Ursus arctos)

Baylisascaris transfuga is a roundworm that has been reported worldwide in most bear species. In mammals and possibly humans, the larvae of B. transfuga can migrate in the tissues of aberrant hosts with larva migrans syndrome. The current study was performed to identify B. transfuga in faecal samples from free-ranging brown bears in the Tatra Mountains National Park in southern Poland. A commercial kit was used to extract genomic DNA directly from faecal samples. Additionally, a Chelex resin-based technique was successfully implemented to prepare a PCR template from eggs retrieved by flotation. Based on the flotation results of 32 collected faecal samples, the prevalence of B. transfuga was 15.6%. The parasite was confirmed in samples found to be positive during the initial flotation by a molecular assay using DNA isolated directly from faeces. The retrieved eggs were confirmed as B. transfuga after their DNA was extracted using the Chelex protocol. Based on PCR amplification and sequencing of a 413-bp segment of cytochrome c oxidase 1 (COI), the obtained sequence was 100% identical to the COI segment of B. transfuga after a BLAST comparison to the GenBank™ database. The current study includes the first molecular confirmation of B. transfuga in brown bears in the western part of the Carpathians. We show that direct extraction of parasite DNA from bear faeces is efficient for molecular assays. As an alternative, we present the effectiveness of a Chelex-based technique for fast and convenient DNA isolation from the difficult-to-disrupt eggs of B. transfuga for PCR. Molecular tests of parasite DNA extracted directly from faecal material have limits of detection related to the amount of eggs in the samples. Thus, using classical flotation to obtain eggs for PCR may increase the credibility of the results, particularly in cases with a low number of excreted eggs. The Chelex resin protocol has potential for application in studies of intestinal parasites in wildlife for which conventional flotation is routinely used for microscopy

Hypernetwork approach to generating point clouds

In this work, we propose a novel method for generating 3D point clouds that leverage properties of hyper networks. Contrary to the existing methods that learn only the representation of a 3D object, our approach simultaneously finds a representation of the object and its 3D surface. The main idea of our HyperCloud method is to build a hyper network that returns weights of a particular neural network (target network) trained to map points from a uniform unit ball distribution into a 3D shape. As a consequence, a particular 3D shape can be generated using point-by-point sampling from the assumed prior distribution and transforming sampled points with the target network. Since the hyper network is based on an auto-encoder architecture trained to reconstruct realistic 3D shapes, the target network weights can be considered a parametrization of the surface of a 3D shape, and not a standard representation of point cloud usually returned by competitive approaches. The proposed architecture allows finding mesh-based representation of 3D objects in a generative manner while providing point clouds en pair in quality with the state-of-the-art methods