Recent progress in biodegradable polymers and nanocomposite-based packaging materials for sustainable environment

Plastic-based materials are frequently used in packaging and can be seen universally in both the developed and developing societies. At present, most of the currently used food packaging materials are nondegradable and are creating serious environmental problems. New technologies are being explored and developed to study the complex interaction between the food packaging materials and food. For example, nanocomposite of cellulose constitutes environmentally friendly packaging, which is easily recycled by combustion and requires low power consumption in production. There are several such biodegradable materials which are available at a low price, have good mechanical properties and allow disposal in the soil. This is advantageous because biological degradation produces only carbon dioxide, water, and inorganic compounds to name a few. It has also been discovered that biodegradable plastics made of such materials can be disposed of together with organic waste. The widespread use of biopolymers in the place of standard plastics would help to reduce the weight of waste. Therefore, biodegradable materials take part in the natural cycle “from nature to nature” and play an important role for environmental sustainability. So, in this article, we briefly summarize the different characteristic of biodegradable polymers being used in food packaging applications

Złośliwy nowotwór osłonek nerwów obwodowych o umiejscowieniu w sterczu

The diagnostic and therapeutic approach to prostatic neurosarcoma, currently known as a malignant peripheral nerve sheath tumor (MPNst) of the prostate, due to its rarity, is not well established. Our presenting case was a 73 year old patient, admitted to the Hospital with suspicion of a prostatic tumor. The patient underwent surgical resection of the described pathological mass. Gross appearance of the pathological examination revealed a yellow-gray colored tumor, 12 × 6 × 7 cm in size. On cross-section: tumor heterogeneity, fatty, yellow-gray, with no foci of necrosis, but with a few cysts of 1–3 cm in size, with a gelatinous substance. Microscopic examination — showed neurosarcoma of the prostate. The patient died at six months follow-up, due to cardiovascular insufficiency.Postępowanie diagnostyczne i terapeutyczne u pacjentów z nerwiakomięsakami prostaty (aktualnie klasyfikowanymi jako złośliwe nowotwory osłonek nerwów obwodowych) pozostaje nieokreślone z powodu rzadkiej na nie zapadalności. Przedstawiamy przypadek 73-letniego chorego, przyjętego do szpitala z powodu nowotworu stercza, który został poddany wycięciu zmiany. Makroskopowo stwierdzono żółto-szarawy guz o wymiarach 12 × 6 × 7 cm, na przekroju o niejednorodnej budowie z zawartością tkanki tłuszczowej, bez ognisk martwicy, ale z obecnością kilku torbieli o wymiarach 1–3 cm, wypełnionych treścią galaretowatą. Badanie mikroskopowe ujawniło cechy nerwiakomięsaka. Pacjent zmarł sześć miesięcy po operacji w następstwie niewydolności krążenia

Structural and functional characterization of an intradiol ring-cleavage dioxygenase from the polyphagous spider mite herbivore Tetranychus urticae Koch

Genome analyses of the polyphagous spider mite herbivore Tetranychus urticae (two-spotted spider mite) revealed the presence of a set of 17 genes that code for secreted proteins belonging to the "intradiol dioxygenase-like" subgroup. Phylogenetic analyses indicate that this novel enzyme family has been acquired by horizontal gene transfer. In order to better understand the role of these proteins in T. urticae, we have structurally and functionally characterized one paralog (tetur07g02040). It was demonstrated that this protein is indeed an intradiol ring-cleavage dioxygenase, as the enzyme is able to cleave catechol between two hydroxyl-groups using atmospheric dioxygen. The enzyme was characterized functionally and structurally. The active site of the T. urticae enzyme contains an Fe3+ cofactor that is coordinated by two histidine and two tyrosine residues, an arrangement that is similar to those observed in bacterial homologs. However, the active site is significantly more solvent exposed than in bacterial proteins. Moreover, the mite enzyme is monomeric, while almost all structurally characterized bacterial homologs form oligomeric assemblies. Tetur07g02040 is not only the first spider mite dioxygenase that has been characterized at the molecular level, but is also the first structurally characterized intradiol ring-cleavage dioxygenase originating from a eukaryote

O problemach współczesnej komparatystyki rozmawiają Maria Korytowska, Marta Skwara, Olga Płaszczewska, Bogusław Bakuła, Tomasz Bilczewski, Andrzej Borowski, Andrzej Hejmej i Tadeusz Sławek.

O problemach współczesnej komparatystyki rozmawiają Maria Korytowska, Marta Skwara, Olga Płaszczewska, Bogusław Bakuła, Tomasz Bilczewski, Andrzej Borowski, Andrzej Hejmej i Tadeusz Sławe

ROZMOWA „WIELOGŁOSU”

Rozmowa „Wielogłosu”: O problemach współczesnej komparatystyk

Crystal structure of thebaine 6-O-demethylase from the morphine biosynthesis pathway

Thebaine 6-O-demethylase (T6ODM) from Papaver somniferum (opium poppy) is a key enzyme in the morphine biosynthesis pathway that belongs to the non-heme 2-oxoglutarate/Fe(II)-dependent dioxygenases (ODD) family. Initially, T6ODM was characterized as an enzyme catalyzing Odemethylation of thebaine to neopinone and oripavine to morphinone, however recently the substrate range of T6ODM was expanded to a number of various benzylisoquinoline alkaloids. Here, we present crystal structures of T6ODM in complexes with 2-oxoglutarate (T6ODM:2OG, PDB: 5O9W) and succinate (T6ODM:SIN, PDB: 5O7Y). The arrangement of the T6ODM’s active site is typical for proteins from the ODD family, but the enzyme is characterized by a large substrate binding cavity, whose volume can partially explain the T6ODM promiscuity. Moreover, the size of the cavity allows for binding of multiple molecules at once, posing a question about substrate-driven specificity of the enzyme

Versatile approach for functional analysis of human proteins and efficient stable cell line generation using FLP-mediated recombination system

Deciphering a function of a given protein requires investigating various biological aspects. Usually, the protein of interest is expressed with a fusion tag that aids or allows subsequent analyses. Additionally, downregulation or inactivation of the studied gene enables functional studies. Development of the CRISPR/Cas9 methodology opened many possibilities but in many cases it is restricted to non-essential genes. Recombinase-dependent gene integration methods, like the Flp-In system, are very good alternatives. The system is widely used in different research areas, which calls for the existence of compatible vectors and efficient protocols that ensure straightforward DNA cloning and generation of stable cell lines. We have created and validated a robust series of 52 vectors for streamlined generation of stable mammalian cell lines using the FLP recombinase-based methodology. Using the sequence-independent DNA cloning method all constructs for a given coding-sequence can be made with just three universal PCR primers. Our collection allows tetracycline-inducible expression of proteins with various tags suitable for protein localization, FRET, bimolecular fluorescence complementation (BiFC), protein dynamics studies (FRAP), co-immunoprecipitation, the RNA tethering assay and cell sorting. Some of the vectors contain a bidirectional promoter for concomitant expression of miRNA and mRNA, so that a gene can be silenced and its product replaced by a mutated miRNA-insensitive version. Our toolkit and protocols have allowed us to create more than 500 constructs with ease. We demonstrate the efficacy of our vectors by creating stable cell lines with various tagged proteins (numatrin, fibrillarin, coilin, centrin, THOC5, PCNA). We have analysed transgene expression over time to provide a guideline for future experiments and compared the effectiveness of commonly used inducers for tetracycline-responsive promoters. As proof of concept we examined the role of the exoribonuclease XRN2 in transcription termination by RNAseq