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Povzetek: V članku je predstavljena črnika (Quercus ilex L.), ena glavnih drevesnih vrst evmediteranske flore na območju Slovenije, kjer raste na razpršenih nahajališčih na severni meji svojega naravnega areala. Glavni namen raziskave je bil preučiti morfološko variabilnost njenih listov. V raziskavo je bilo vključenih sedem naravnih populacij črnike v Sloveniji. Morfometrijska analiza je pokazala veliko variabilnost listov in značilne razlike med populacijami, ki smo jih potrdili pri skoraj vseh preučevanih morfoloških znakih. Na podlagi ugotovljenih morfoloških razlik lahko slovenske populacije razdelimo v tri geografskomorfološke skupine: i) populacije na Goriškem (Sabotin, Sv. Gora in Lijak), ii) Nanos - Osp in iii) populaciji v dolini reke Dragonje. Morfološka variabilnost kot odsev genetske variabilnosti je posledica prilagoditve na lokalne okoljske razmere. Črnika v Sloveniji za zdaj ni ogrožena vrsta, vendar bi bilo pri morebitnih aktivnih varstvenih ukrepih za njeno ohranjanje smiselno čimbolj upoštevati ugotovljene tri geografsko-morfološke skupine.
Ključne besede: črnika, Quercus ilex, morfološka variabilnost, Slovenija, drevesni listi
Objavljeno v DiRROS: 12.09.2024; Ogledov: 173; Prenosov: 589
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Povzetek: The systemic toxicity of cyclic peptides produced by cyanobacteria (CCPs) is not yet completely understood. Apart from the most known damages to the liver and kidneys, symptoms of their neurotoxicity have also been reported. Hepatotoxic CCPs, like microcystins, as well as non-hepatotoxic anabaenopeptins and planktopeptins, all exhibit cytotoxic and cytostatic effects on mammalian cells. However, responses of different cell types to CCPs depend on their specific modes of interaction with cell membranes. This study demonstrates that non-hepatotoxic planktopeptin BL1125 and anabaenopeptins B and F, at concentrations up to 10 µM, affect normal and tumor human astrocytes (NHA and U87-GM) in vitro by their almost immediate insertion into the lipid monolayer. Like microcystin-LR (up to 1 µM), they inhibit Ser/Thr phosphatases and reorganize cytoskeletal elements, with modest effects on their gene expression. Based on the observed effects on intermediate filaments and intermediate filament linkage elements, their direct or indirect influence on tubulin cytoskeletons via post-translational modifications, we conclude that the basic mechanism of CCP toxicities is the induction of inter- and intracellular communication failure. The assessed inhibitory activity on Ser/Thr phosphatases is also crucial since the signal transduction cascades are modulated by phosphorylation/dephosphorylation processes.
Ključne besede: astrocytes, cyclic cyanobacterial peptides, cytoskeletal organization, Ser/Thr phosphatases, systemic toxicity, cyanobacteria
Objavljeno v DiRROS: 28.08.2024; Ogledov: 192; Prenosov: 269
Celotno besedilo (21,09 MB)
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Povzetek: One specimen of the dusky spinefoot, Siganus luridus (Rüppell, 1829) (+, total length = 17.3 cm, total weight = 87.61 g), a lessepsian migrant, was captured in the Mljet Channel (Southern Adriatic, Croatian coast) on 15 November 2010. This is the second record of this species from the Adriatic, but first well documented and based on the captured specimen. First record occurred earlier in the Northern Adriatic, but was based solely on underwater observations.
Ključne besede: fishes, ichthyology, Adriatic sea, Siganidae, lessepsian migrants, diversity, origins, Mediterranean, new record, Adriatic Sea
Objavljeno v DiRROS: 07.08.2024; Ogledov: 202; Prenosov: 99
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Povzetek: Background Omics approaches have significantly increased our understanding of biological systems. However, they have had limited success in explaining the dramatically increased productivity of commercially important natural products by industrial high-producing strains, such as the erythromycin-producing actinomycete Saccharopolyspora erythraea. Further yield increase is of great importance but requires a better understanding of the underlying physiological processes. Results To reveal the mechanisms related to erythromycin yield increase, we have undertaken an integrated study of the genomic, transcriptomic, and proteomic differences between the wild type strain NRRL2338 (WT) and the industrial high-producing strain ABE1441 (HP) of S. erythraea at multiple time points of a simulated industrial bioprocess. 165 observed mutations lead to differences in gene expression profiles and protein abundance between the two strains, which were most prominent in the initial stages of erythromycin production. Enzymes involved in erythromycin biosynthesis, metabolism of branched chain amino acids and proteolysis were most strongly upregulated in the HP strain. Interestingly, genes related to TCA cycle and DNA-repair were downregulated. Additionally, comprehensive data analysis uncovered significant correlations in expression profiles of the erythromycin-biosynthetic genes, other biosynthetic gene clusters and previously unidentified putative regulatory genes. Based on this information, we demonstrated that overexpression of several genes involved in amino acid metabolism can contribute to increased yield of erythromycin, confirming the validity of our systems biology approach. Conclusions Our comprehensive omics approach, carried out in industrially relevant conditions, enabled the identification of key pathways affecting erythromycin yield and suggests strategies for rapid increase in the production of secondary metabolites in industrial environment.
Ključne besede: aktinomicete, Saccharopolyspora erythraea, sekundarni metaboliti, antibiotiki, eritromicin, biosinteza, metabolno inženirstvo, proteomika
Objavljeno v DiRROS: 25.07.2024; Ogledov: 233; Prenosov: 161
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Povzetek: The genetic platforms of Deinococcus species remain the only systems in which massive ionizing radiation (IR)-induced genome damage can be investigated in vivo at exposures commensurate with cellular survival. We report the whole genome sequence of the extremely IR-resistant rod-shaped bacterium Deinococcus ficus KS 0460 and its phenotypic characterization. Deinococcus ficus KS 0460 has been studied since 1987, first under the name Deinobacter grandis, then Deinococcus grandis. The D. ficus KS 0460 genome consists of a 4.019 Mbp sequence (69.7% GC content and 3894 predicted genes) divided into six genome partitions, five of which are confirmed to be circular. Circularity was determined manually by mate pair linkage. Approximately 76% of the predicted proteins contained identifiable Pfam domains and 72% were assigned to COGs. Of all D. ficus KS 0460 proteins, 79% and 70% had homologues in Deinococcus radiodurans ATCC BAA-816 and Deinococcus geothermalis DSM 11300, respectively. The most striking differences between D. ficus KS 0460 and D. radiodurans BAA-816 identified by the comparison of the KEGG pathways were as follows: (i) D. ficus lacks nine enzymes of purine degradation present in D. radiodurans, and (ii) D. ficus contains eight enzymes involved in nitrogen metabolism, including nitrate and nitrite reductases, that D. radiodurans lacks. Moreover, genes previously considered to be important to IR resistance are missing in D. ficus KS 0460, namely, for the Mn-transporter nramp, and proteins DdrF, DdrJ and DdrK, all of which are also missing in Deinococcus deserti. Otherwise, D. ficus KS 0460 exemplifies the Deinococcus lineage.
Ključne besede: Deinococcus-Thermus, Deinococcaceae, Deinococcus ficus, radiation-resistant, rod-shaped, phenotype characterization, genome analysis, phylogenetic analysis
Objavljeno v DiRROS: 25.07.2024; Ogledov: 227; Prenosov: 160
Celotno besedilo (1,22 MB)
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