Lignocelulozna biomasa je važan obnovljivi izvor energije i koristi se kao sirovina u proizvodnji biogoriva druge generacije. Zbog vrlo složene strukture, učinkovita enzimska hidroliza ...lignoceluloznebiomase je ključni izazov današnjice. Litička polisaharidna monooksigenaza (LPMO) je nedavno otkrivena vrsta enzima koji sadrže bakar, a imaju značajnu ulogu u oksidativnoj razgradnji netopivih biljnih polisaharida i topivih oligosaharida. Stoga je prepoznat kao jedan od bitnih enzima u održivoj pretvorbi lignocelulozne biomase, a važnost ovog enzima potvrđena je brojnim istraživanjima. Nakon reduktivne aktivacije, LPMO cijepa supstrat i potiče razgradnju biomase hidrolitičkim enzimima. U ovom preglednom radu, opisana je uloga LPMO u razgradnji lignocelulozne biomase s naglaskom na strukturu LPMO i mehanizma djelovanja LPMO na celuloznim supstratima.
Lignocellulosic biomass is an important renewable energy source and is used as a feedstock for the production of second generation biofuels. Due to its very complex structure, efficient enzymatic hydrolysis of lignocellulosic biomass is a major challenge today. Lytic polysaccharide monooxygenase (LPMO) is a recently discovered type of copper-containing enzyme that plays a significant role in the oxidative degradation of insoluble plant polysaccharides and soluble oligosaccharides. Therefore, it is considered one of the essential enzymes for the sustainable conversion of lignocellulosic biomass, and its importance has been confirmed by numerous studies. After reductive activation, LPMO cleaves the substrate and promotes biomass degradation by hydrolytic enzymes. In this review, the role of LPMO in the degradation of lignocellulosic biomass is described, focusing on the structure of LPMO and the mechanism of action of LPMO on cellulosic substrates.
Proizvodnja nanoceluloze iz lignoceluloznih sirovina Rezić, Tonči; Drdić, Maria; Radić, Ines ...
Hrvatski časopis za prehrambenu tehnologiju, biotehnologiju i nutricionizam,
12/2022, Letnik:
17, Številka:
1-2
Journal Article, Paper
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Nanoceluloza je prirodan i biorazgradiv materijal koji se dobiva iz obnovljivih lignoceluloznih sirovina kao sto su drvna biomasa, poljoprivredni ostaci i ostaci iz proizvodnje celuloze i papira. U ...posljednje vrijeme nanoceluloza kao zeleni materijal modernog doba zadobiva sve veći interes zbog svojih atraktivnih karakteristika kao što su izvrsna mehanička svojstva, velika površina te veliki broj hidroksilnih skupina koji omogućava veliki raspon modifikacija materijala. U ovome radu biti će opisani načini proizvodnje nanoceluloze iz lignoceluloznih sirovina korištenjem mehaničkih i fizikalno-kemijskih metoda, a poseban naglasak će bit dan na metode predobrade korištenjem enzima.
Nanocellulose is a natural and biodegradable material derived from renewable lignocellulosic raw materials such as wood biomass, agricultural residues, and residues from cellulose and paper manufacturing. Recently, nanocellulose has attracted increasing interest as a green material of the modern era due to its attractive characteristics such as excellent mechanical properties, large surface area, and large number of hydroxyl groups, which allow a wide range of material modifications. In this paper, the methods of producing nanocellulose from lignocellulosic raw materials using mechanical and physicochemical processes are described, with particular attention paid to pretreatment methods using enzymes
Quinolino7,8-hquinoline is a superbasic compound, with a pK aH in acetonitrile greater than that of 1,8-bis(dimethylaminonaphthalene) (DMAN), although its synthesis and the synthesis of its ...derivatives can be problematic. The use of halogen derivatives 4,9-dichloroquinolino7,8-hquinoline (16) and 4,9-dibromoquinolino7,8-hquinoline (17) as precursors has granted the formation of a range of substituted quinolinoquinolines. The basicity and other properties of quinolinoquinolines can be modified by the inclusion of suitable functionalities. The experimentally obtained pK aH values of quinolino7,8-hquinoline derivatives show that N 4,N 4,N 9,N 9-tetraethylquinolino7,8-hquinoline-4,9-diamine (26) is more superbasic than quinolino7,8-hquinoline. Computationally derived pK aH values of quinolinoquinolines functionalized with dimethylamino (NMe2), 1,1,3,3-tetramethylguanidino (NC(NMe2)2) or N,N,N′,N′,N″,N″-hexamethylphosphorimidic triamido (NP(NMe2)3) groups are significantly greater than those of quinolino7,8-hquinoline. Overall, electron-donating functionalities are observed to increase the basicity of the quinolinoquinoline moiety, while the substitution of electron-withdrawing groups lowers the basicity.
Mletački trgovački brod natovaren raznovrsnim teretom potonuo je kod otočića Gnalića krajem listopada ili početkom studenoga 1583. Brodski se teret sastojao od sirovina, poluproizvoda i gotovih ...proizvoda namijenjenih carigradskome tržištu i sultanovome dvoru, što je višestruko potvrđeno arheološkim i povijesnim istraživanjima. Među gotovim proizvodima posebno se ističe velika količina staklenih predmeta podijeljenih u dvije glavne skupine: šuplje i ravno staklo. Prva skupina obuhvaća raznolike oblike stolnoga posuđa, spremnika za hranu i piće i staklenih perli, dok se u drugoj nalaze prozorska stakla i stakla za ogledala. Nakon službenoga otkrića nalazišta 1967. godine, organizirano je pet zaštitnih istraživačkih kampanja s ciljem pravovremenoga spašavanja najvrjednijih nalaza. Nakon 1973. aktivnosti zaštitne prirode kratkotrajno su obnovljene 1996., a sustavno istraživanje, primjereno značenju i stanju nalazišta, započelo je tek 2012. godine. Prve sistematizacije staklene građe izradili su Sofija Petricioli i Astone Gasparetto. U okviru međunarodnoga projekta The Heritage of the Serenissima 2004. godine Irena Lazar, Hugh Willmott i Caroline Jackson sustavno su obradili staklene nalaze. Tijekom istraživanja 2012. – 2020., usmjerenih poglavito na otkrivanje i dokumentiranje brodske konstrukcije, izvađene su tisuće ulomaka staklenih predmeta. Iako je u većini slučajeva riječ o primjercima stolnoga posuđa i ravnoga stakla, koji se u potpunosti uklapaju u do sada predloženu tipologiju staklenih nalaza iz brodskoga tereta, u nekim slučajevima primjećuju se i određene razlike. U radu su predstavljeni novi nalazi koji dopunjuju dosadašnje spoznaje ili ukazuju na mogućnost različite interpretacije ranijih nalaza.
A Venetian merchant ship loaded with various cargo sank off the islet of Gnalić in late October or early November 1583. As confirmed by archaeological and historical research, the ship’s cargo consisted of raw materials, semi-finished and finished products, intended for the Constantinople market and the sultan’s court. Among the finished products, a large amount of glass objects stands out. It is divided into two main groups: hollow and flat glass. The first group includes various forms of tableware, food and beverage containers and glass beads, while the second group includes window panes and mirror glasses. After the official discovery of the site in 1967, five rescue research campaigns were organized with the aim of salvaging the most valuable finds. After 1973, rescue research was briefly renewed in 1996. The systematic research, appropriate to the significance and condition of the site, begun just in 2012. The first systematization of glass was made by Sofia Petricioli and Astone Gasparetto. In 2004, Irena Lazar, Hugh Willmott and Caroline Jackson systematically processed the glass finds, in the framework of the international project The Heritage of the Serenissima. During the 2012–2020 research, focused mainly on the detection and documentation of ship hull, thousands of fragments of glass objects were recovered. Although in most cases these are examples of tableware and flat glass, which completely fit into the hitherto proposed typology of glass finds from the ship’s cargo, in some cases certain differences were noticed. This paper presents new finds that supplement previous knowledge or indicate the possibility of different interpretation of previous finds.
Epilepsy is one of the most common chronic diseases in children, and cannot be controlled with conventional antiepileptic drugs in 30% of cases. Therefore, in these cases, alternative approach such ...as corticosteroid therapy (CT) is used. The aim of this study was to analyze different types of CT used to treat drug-resistant childhood epilepsies, treated at Rijeka University Hospital Centre during a 5-year period (2016-2020). This retrospective study included 32 patients. The following parameters were analyzed: number of patients with a particular diagnosis, average age (in months) at the onset of epilepsy, average epilepsy duration (in months) prior to CT, average number of antiepileptic drugs used prior to CT, presence of changes on magnetic resonance imaging (MRI), presence of comorbidities, and types of CT. The average age at the onset of epilepsy was 14 months and average epilepsy duration prior to CT was 16 months. On average, 5 antiepileptic drugs were used prior to CT. MRI changes were present in 53.13% and comorbidities in 81.25% of study patients. Prednisone therapy was used in 28.13%, combined therapy with prednisone and methylprednisolone in 65.63%, and methylprednisolone in 6.25% of patients. Study results revealed the use of CT for particular diagnosis to differ among the centers, as well as within the same center, so it is important to highlight the importance of reaching universal guidelines for CT therapy of childhood epilepsies.
Hypoxic and anoxic niches of meromictic lakes are important sites for studying the microbial ecology of conditions resembling ancient Earth. The expansion and increasing global distribution of such ...environments also means that information about them serves to understand future phenomena. In this study, a long-term chemical dataset (1996–2015) was explored together with seasonal (in 2015) information on the diversity and abundance of bacterial and archaeal communities residing in the chemocline, monimolimnion and surface sediment of the marine meromictic Rogoznica Lake. The results of quantitative PCR assays, and high-throughput sequencing, targeting 16S rRNA genes and transcripts, revealed a clear vertical structure of the microbial community with Gammaproteobacteria (Halochromatium) and cyanobacteria (Synechococcus spp.) dominating the chemocline, Deltaproteobacteria and Bacteroidetes dominating the monimolimnion, and significantly more abundant archaeal populations in the surface sediment, most of which affiliated to Nanoarchaeota. Seasonal changes in the community structure and abundance were not pronounced. Diversity in Rogoznica Lake was found to be high, presumably as a consequence of stable environmental conditions accompanied by high dissolved carbon and nutrient concentrations. Long-term data indicated that Rogoznica Lake exhibited climate changes that could alter its physico-chemical features and, consequently, induce structural and physiological changes within its microbial community.
Background: Autologous stem cell transplantation (ASCT) after induction treatment is standard of care for multiple myeloma (MM) for the last 30 years. Two transplantations up-front (so-called tandem ...transplant) were standard of care for all MM patients. With the use of new antimyeloma agents (such as proteasome inhibitors, immunomodulators and especially monoclonal antibodies) this approach has changed and tandem transplant is now reserved mainly for patients with high-risk disease, defined by revised international staging system (R-ISS). There have been reports which cast further doubts on the value of the more aggressive tandem ASCT approach, as well as reports suggesting higher incidence of secondary primary malignancies (SPM) after high dose therapy and ASCT. Aims: To describe long-term outcomes of MM patients treated with ASCT (single, delayed, and tandem) and the rate of secondary primary malignancies. Methods: a retrospective analysis of outcomes of 577 MM patients who underwent 865 ASCT procedures between 1993 and 2017 was performed. Data were collected from 3 transplant centres and 9 other haematological centres in which MM patients were treated pre- and post-transplant. During that period treatment strategies changed significantly from single to tandem to salvage second ASCT. Results: there were 577 patients included. Median age at first transplant was 58 years (range 22 - 74). There were 295 female and 282 male patients. 346 patients received VAD (vincristine, doxorubicin, dexamethasone) and 231 received bortezomib and/or thalidomide (PI/IMiD) based regiments as induction therapy. All patients received high dose melphalan for pretransplant conditioning, 32 in combination with total body irradiation. Tandem ASCT (defined as second transplantation performed within 6 months after the first) was performed in 226 patients, single ASCT in 262 and salvage second (after relapse and/or progression) in 89 patients. Median overall survival (OS) for the entire group is 81.9 months and median progression free survival (PFS) 38.9 months. Tandem ASCT in comparison to single and second salvage transplantation resulted in statistically significant better OS (115 vs. 83 vs. 67 months respectively, p < 0.0001) and PFS (48 vs. 32. vs. 28 months respectively, p < 0.0001). There was no difference in outcomes regarding type of induction therapy, VAD vs. PI/IMiD based: median OS was 83 vs. 80 months, respectively (p=0.39) and median PFS was 39 vs. 38 months, respectively (p=0.15). 17.6% percent of patients who were treated with tandem ASCT are progression-free more than 10 years after the procedure while 10-year OS is 31.9%. 51 patients (8.8%) developed secondary malignancies (SPM). Most common SPM were lung carcinoma (10 patients), colorectal carcinoma (7 patients), myelodysplastic syndrome/acute myeloid leukaemia (6 patients), breast carcinoma (4 patients) and melanoma (4 patients). Of those 19 died due to SPM (3% of the entire patient group). There was no correlation between number of ASCT and SPM (p=0.87). Conclusion: in our group of patients tandem ASCT resulted in superior OS and PFS in comparison to single and/or salvage ASCT. Interestingly, we did not observe benefit of new drugs (PI/IMiD) in induction therapy regarding outcomes. This peculiar result might be due to rather late availability of these drugs in front line settings (bortezomib and thalidomide since 2015) and time period taken for analysis (up to 2018). SPM rate was similar to other reports and did not show significant correlation with number of ASCT. More than 15% of patients treated with tandem ASCT experienced very prolonged PFS and almost 32% had OS longer than 10 years.
Bacteria are the most important microorganisms in the world oceans, accounting for up to 75% of the total biomass. They are responsible for fundamental biogeochemical processes and therefore often ...used as ecological indicators. In this study, bacteria were quantified by flow cytometry and their diversity assessed by High Throughput Sequencing (HTS) in the southern Adriatic Sea. The most abundant bacterial groups were also quantified by qPCR. The samples were collected from the surface to the seabed over a total of 16 different depths at four stations during the late winter BIOTA (BIO-Tracing Adriatic water masses) cruise conducted in March 2016. The investigated area showed unusual water mass properties and was characterized by a shallow mixed layer, which differed from the usual winter convection conditions, typical of middle-altitude ecosystems and important for the seasonal picoplankton dynamics of this area. Heterotrophic bacteria were separated into HNA (relative High Nucleic Acid content) and LNA (Low Nucleic Acid content) subpopulations with abundances up to 1.8 × 105 and 8.8 × 105 cells mL−1, respectively. HNA dominated at offshore stations reaching their maximum at depths below the euphotic zone. The bacterial community was dominated by Alphaproteobacteria, accounting for >40% of the total sequence reads and were mainly represented by the SAR11 clade (90.84%), followed by Marinimicrobia (18% of the total sequence reads), mainly represented by clade SAR406 (8.44%). Distinctive bacterial groups were found in the euphotic layer (Bacteroidetes and Actinobacteria) and aphotic layer samples (Deltaproteobacteria, Marinimicrobia, Chloroflexi, Acidobacteria and Planctomycetes). Results of the qPCR analyses further confirmed HTS results with highest abundances obtained for Alphaproteobacteria, followed by Gammaproteobacteria and Bacteroidetes. The adopted multiple approach, combining different molecular tools, critically supported by optics and flow cytometry, reveal changes in the bacterial assemblages during the unusual thermohaline conditions observed in 2016 in the southern Adriatic Sea.
•Multilayer approach provided in depth characterization of microbial community.•In winter 2016 a 200 m mixed overlaid stratified waters were formed.•Euphotic and aphotic layer harbor distinctive bacterial communities•Communities distribution was affected by the absence of the deep-water convection.•α-Proteobacteria and γ-proteobacteria represented dominant bacterial populations.
M06-2X/6-311++G(2df,2pd)//M06-2X/6-31+G(d) computations were employed to investigate the intrinsic gas phase basicity of strained nitrogen heterocycles involving aziridine, azetidine, pyrrolidine and ...piperidine, together with their N-methyl and N-phenyl derivatives, NR(CH.sub.2).sub.n (n = 2-5; R = H, Me and Ph). Basicity constants were compared with the corresponding acyclic counterparts, NR(CH.sub.3).sub.2 (R = H, Me and Ph), and were, based on triadic analysis, resolved into contributions mirroring features of both initial base and the final protonated form as well as their interplay, thus offering quantitative insight into the obtained results. In general, the N-methyl derivatives provided strongest bases investigated here, and, within each group of molecules, the basicity increased on going from three- to six-membered rings, consistent with a decrease in ring strain, with four-membered systems already surpassing or coming close to the basicity of the acyclic gauge molecule. Calculated basicities were found in a very good agreement with available experimental data, except for N-methylazetidine, where a remarkable discrepancy was revealed, suggesting that this system should be experimentally reassessed and its gas- phase basicity parameters revised. Triadic analysis showed different behaviour of individual contributions governing basicities, both among and within distinct families of molecules. It also convincingly demonstrated that, if a proper and a quantitatively accurate interpretation of observed basicity trends is desired, one should not rely only on concepts such as localized reactive hybrid orbitals (RHO) or thus derived nitrogen electron-donating ability (T. Ohwada et al., J. Org. Chem. 69 (2004) 7486), which take into account only properties of the initial base in question, but rather consider protonation reaction in its entirety. (doi: 10.5562/cca2121) Keywords: Baeyer ring strain, protonation, substituent effect, superbases, triadic formula
Adriatic, the northernmost part of the Mediterranean Sea, due its oligotrophy, topography, and hydrology dynamics, and complex circulation patterns, was suggested as an important study site for rapid ...climatology impacts. Its southern part is mainly oligotrophic and dominated by picophytoplankton, with cyanobacteria as main representatives. Diversity and distribution patterns of different Prochlorococcus ecotypes were investigated by molecular tools and flow cytometry during the winter convection event in the southern Adriatic (BIOTA winter cruise; February/March 2015). Phylogenetic diversity based on clone libraries of the 16S–23S ribosomal DNA ITS region, as well as flow cytometry (histograms of red fluorescence), indicated presence of 2 different Prochlorococcus in the Adriatic. HLI, as a typical clade for Mediterranean Sea, was likewise found to be dominant Prochlorococcus in the Adriatic, followed by less abundant LLI clade. In addition, Prochlorococcus were found to co-occur with diverse Synechococcus population (53% and 47% of obtained ITS sequences, respectively). Different Prochlorococcus ecotypes had similar patterns of vertical distribution, predominantly occupying upper 100m depth layer, but their distribution was clearly affected by the heterogeneity of hydrological conditions, nitrogen concentration and temperature along vertical and horizontal sampling points. Different studies pointed out that, as a consequence of climate changes, serious alteration of biological and ecological patterns are already taking place Therefore, understanding of the distribution and abundance of picophytoplankton in Adriatic, being still limited, is much needed baseline for predicting possible biogeochemical impact of future environmental changes.
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