{"title":"Auxin Amidohydrolases – From Structure to Function: Revisited","authors":"Ana Smolko, J. Ludwig-Müller, B. Salopek-Sondi","doi":"10.5562/CCA3356","DOIUrl":"https://doi.org/10.5562/CCA3356","url":null,"abstract":"The control of plant growth and development is a well-coordinated process between exogenous and endogenous signals. Auxins are plant hormones belonging to the endogenous signals, which control a vast array of different processes. While auxins are growth promoting at low concentrations, higher levels are often inhibitory. Therefore, the tight control of auxin concentrations in a given plant tissue is essential. Among several processes that participate in auxin homeostasis, we focused herein on the process of reversible auxin conjugation that considers the synthesis of inactive auxin conjugates, which can be hydrolyzed back to the active form by so called auxin conjugate hydrolases. Although these proteins have been known for quite some time, their role in plants is still not clear, especially since novel hydrolases with different substrate specificities have been isolated. Thus, we have revisited the knowledge about auxin hydrolases, from their structure and biochemistry to the role in plant development and in dealing with unfavorable climate conditions.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"233-239"},"PeriodicalIF":0.3,"publicationDate":"2018-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43448225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Structure and Reactivity Relationships in Methyl and Hydrido Complexes of Platinum(II) by Group 15 Donor Atom Ligands","authors":"S. Otto, E. Botha, A. Roodt","doi":"10.5562/CCA3344","DOIUrl":"https://doi.org/10.5562/CCA3344","url":null,"abstract":"Square-planar substitution reactions (chlorido for iodide, trans to methyl and hydrido as non-labile ligands) was kinetically investigated in chloroform solution in a series of platinum(II) trans-[PtRCl(L)2] complexes (R = Me: L = PPh3, 1; PPh2Fc, 2; P(NMe2)3, 3; AsPh3, 5; As(4-Me-Ph)3, 6; R = H: L = PPh3, 7) and cis-[PtMeCl(Ph2PFcPPh2)], 4. The reactions follow the normal associative mode of activation, but with equilibria present in all steps, with rate constants for the direct substitution pathway, k12, of (9.1 ± 1.0) × 10−4, 0, (1.389 ± 0.016)×10−2, (1.51 ± 0.15), (2 ± 4) × 10−3, (2.79 ± 0.04) × 10−2 and 0 mol−1 dm3 s−1 at 298 K for 1 to 7 respectively. The corresponding second order rate constants for the solvent assisted pathway, k13', were also determined. The activation parameters for the direct and solvent assisted pathways for 3 were determined as ∆H≠ = 60.4 ± 1.4 and 53.7 ± 0.3 kJ mol−1, and ∆S≠ = −78 ± 4 and −142 ± 1 J mol−1 K−1. A significant more than four orders-of-magnitude reactivity range was observed. Crystal structures of trans-[PtMeCl(PPh2Fc)2].2CHCl3.2H2O, trans-[PtMeCl{P(NMe2)3}2], cis-[PtMeCl(Ph2PFcPPh2)].2CHCl3 and trans-[PtHCl(PPh3)2].CH3OH are reported.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"265-279"},"PeriodicalIF":0.3,"publicationDate":"2018-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49504881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Alkali salts of nitranilic and cyanochloranilic acids","authors":"V. Milašinović, K. Molčanov","doi":"10.5562/CCA3333","DOIUrl":"https://doi.org/10.5562/CCA3333","url":null,"abstract":"Series of novel alkali salts of nitranilic acid (3, 6-dinitro-2, 5-dihydroxyquinone) and cyanochloranilic acid (3-cyano-6-chloro-2, 5-dihydroxyquinone), and also of neutral cyanochloranilic acid dihydrate, were prepared and their structures were studied. The nitranilate dianion revealed a considerable conformational flexibility of nitro groups. Steric and inductive effects exerted by different substituents (nitro, cyano and chloro) and their influence on molecular geometry and crystal packing are discussed.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"177-186"},"PeriodicalIF":0.3,"publicationDate":"2018-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47778147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ž. Fiket, M. Ivanić, M. Turk, N. Mikac, G. Kniewald
{"title":"Distribution of trace elements in waters of the Zrmanja River estuary (eastern Adriatic coast, Croatia)","authors":"Ž. Fiket, M. Ivanić, M. Turk, N. Mikac, G. Kniewald","doi":"10.5562/CCA3202","DOIUrl":"https://doi.org/10.5562/CCA3202","url":null,"abstract":"This study aims to investigate the geochemical characteristics of waters of the highly stratified Zrmanja River estuary (eastern Adriatic coast, Croatia). For that purpose, data on salinity and distribution of 16 elements in surface and bottom water of the Zrmanja River estuary was used to assess the spatial variation of trace elements in the estuary water and to identify the main processes governing these variations. The composition of the investigated water was found to be determined primarily by natural factors. Mass concentration levels of dissolved elements were relatively low and typical for unpolluted waters and are considered to primarily reflect the geological and hydrogeological background of the catchment area. The distribution of element mass concentrations along the water column was found to primarily reflect different water masses, the river on the surface and sea at the bottom. Deviation from conservative behaviour for some elements in the bottom water is due to adsorption and desorption processes from the particulate phases.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"29-41"},"PeriodicalIF":0.3,"publicationDate":"2018-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43099298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bibliometric Analysis of Atmospheric Simulation Trends in Meteorology and Atmospheric Science Journals","authors":"Jinfeng Li, Yuanhang Zhang, Xuesong Wang, Y. Ho","doi":"10.5562/CCA3210","DOIUrl":"https://doi.org/10.5562/CCA3210","url":null,"abstract":"This study was designed to evaluate the global scientific output of simulation research in \"meteorology and atmospheric sciences\" for the past 16 years and to assess the characteristics of the atmospheric simulation research patterns, tendencies and methods in the papers, from leading countries and institutes. Data were based on the online version of Science Citation Index, Web of Science from 1992 to 2007. Articles referring to atmospheric simulation were assessed by exponential regression fitting the trend of publication outputs with r 2 = 0.9996, distribution of source countries, source institutes, source titles, author keywords, and keywords plus, and the four most cited articles in these years. By synthetic analysis of the three kinds of keywords, it was concluded that atmospheric simulation research related to \"ozone\", \"climate\", \"circulation\", \"transport\", \"parameterization\" and \"assimilation\" will be foci of atmospheric simulation research in the 21 st century.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"695-705"},"PeriodicalIF":0.3,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42950738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Microstructural Properties of Natural Allophane/Gibbsite from a White Bauxite Deposit in Montenegro","authors":"M. Ristić, S. Krehula, S. Musić","doi":"10.5562/CCA3276","DOIUrl":"https://doi.org/10.5562/CCA3276","url":null,"abstract":"Microstructural properties of white bauxite from Montenegro were investigated. XRD analysis showed the presence of allophane (Al2O3 · 2SiO2 · 3H2O) and gibbsite (γ-Al(OH)3). The allophane phase showed very broadened diffraction lines, thus indicating poor crystallinity as well as very fine nanoparticles in this phase. Upon heating of natural allophane/gibbsite at 1000 °C mullite (Al6Si2O13) was formed, but with a lower degree of crystallinity. FT-IR spectra of allophane, gibbsite and mullite were interpreted. FE-SEM images of natural allophane/gibbsite showed a dominantly amorphous-like morphology. Upon heating of natural allophane/gibbsite two-dimensional (2D) microstructure was visible. EDS analysis showed traces of calcium, potassium, magnesium and iron. The 57Fe Mössbauer spectrum of iron traces showed a small relative intensity magnetic splitting component due to the presence of hematite and a central quadrupole doublet due to the presence of Fe3+ ions substituted for Al3+ in octahedral positions and/or a superparamagnetic fraction of hematite particles. The possible geochemical mechanism of white bauxite formation in Montenegro is discussed.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"65-70"},"PeriodicalIF":0.3,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48155946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Fajković, M. Ivanić, Lovorka Pitarević, I. Nemet, Sanda Rončević, E. Prohić
{"title":"Unsanitary Landfill Fires as a Source of a PCDD/Fs Contamination","authors":"H. Fajković, M. Ivanić, Lovorka Pitarević, I. Nemet, Sanda Rončević, E. Prohić","doi":"10.5562/CCA3145","DOIUrl":"https://doi.org/10.5562/CCA3145","url":null,"abstract":"The aim of this study was to determine whether a combustion process (open burning) on an unsanitary landfill produces polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), for which several media were analysed (smoked air, landfill soil, and lake sediment). The concentration of PCDD/Fs detected in the air increased over 4000 times during the landfill fire, from 0.480 fg m–3 to 1940.4 fg m–3 or expressed as Toxic Equivalency (TEQ) from 0.004 fg TEQ m–3 to 25.72 fg TEQ m–3. Increased values of PCDD/Fs were also determined in the soil from the landfill site (2597.6 ng kg-1, 48.11 ng TEQ kg-1), and the influence of combustion process occurring on the landfill was also registered in the nearby lake sediment (23.17 ng kg–1, 0.03 ng TEQ kg–1). Due to the high sedimentation rate (6.4 mm y–1), a significant contaminant dilution in the lake sediment can be expected. The results of this preliminary study point to the need of implementing a continuous long-term monitoring of PCDD/PCDFs in the landfill surrounding environment.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"71-79"},"PeriodicalIF":0.3,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46563498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yaghoub Pourshojaei, Maryam Nikzad, K. Eskandari, M. Darijani, A. Hassanzadeh, E. Faghih-Mirzaei, A. Asadipour
{"title":"Ultrasound-assisted and Efficient Knoevenagel Condensation Reaction Catalyzed by Silica Sodium Carbonate Nanoparticles","authors":"Yaghoub Pourshojaei, Maryam Nikzad, K. Eskandari, M. Darijani, A. Hassanzadeh, E. Faghih-Mirzaei, A. Asadipour","doi":"10.5562/CCA3261","DOIUrl":"https://doi.org/10.5562/CCA3261","url":null,"abstract":"An efficient and ultrasound-assisted route to the synthesis of arylidene malononitriles/methylcianoor ethylciano acetates in a onepot reaction catalyzed by silica sodium carbonate nanoparticles (SSC NPs) is described. In this reaction, SSC NPs demonstrated high efficiency as catalyst to obtain target products. By this achievement, a wide range of α,β-unsaturated compounds as Knoevenagel condensation products with good to excellent yields are obtained from reaction between numerous arylaldehydes, and malononitrile, methyl cianoacetate or ethyl cianoacetate. Target products which prepared in high yield and high purity can be candidate as important biologically active molecules. This method is an easy, cheap, rapid and highly efficient for the synthesis of desired products. In addition, capability of catalyst to separate from reaction mixture and reuse in further runs and being compatible with green chemistry are considered as other advantages of this procedure. All products were deduced from their FT-IR and FT-NMR spectroscopic and elemental analysis data.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"19-28"},"PeriodicalIF":0.3,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3261","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42359940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Zukić, E. Veljović, S. Špirtović-Halilović, Samija Muratović, A. Osmanović, S. Trifunović, I. Novaković, D. Završnik
{"title":"Antioxidant, Antimicrobial and Antiproliferative Activities of Synthesized 2,2,5,5-Tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1 H -xanthene-1,8(2 H )-dione Derivatives","authors":"S. Zukić, E. Veljović, S. Špirtović-Halilović, Samija Muratović, A. Osmanović, S. Trifunović, I. Novaković, D. Završnik","doi":"10.5562/CCA3225","DOIUrl":"https://doi.org/10.5562/CCA3225","url":null,"abstract":"Ten biologically active 2,2,5,5-tetramethyl-9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione derivatives were synthesized and their structures were confirmed by IR, 1H and 13C NMR spectroscopy and mass spectrometry. Synthesized compounds were scanned for their antioxidant, antimicrobial and antiproliferative activity. Antibacterial activity was tested by the diffusion and dilution method against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, while antifungal activity was tested against Candida albicans and Saccharomyces cerevisiae. Antiproliferative activity was tested against HeLa (cervical carcinoma), SW620 (colorectal adenocarcinoma, metastatic), hepatocellular carcinoma (HEpG2), lung carcinoma cells (A549) and mouse embryo fibroblast cell line (3T3). The best antioxidant activity showed compound 2 with two hydroxy groups substituted on phenyl ring in positions 2' and 3'. The best antimicrobial activity of all synthesized compounds showed compound 8, while the best antiproliferative activity showed compound 6. Results signify the importance of xanthene-1,8-dione derivatives as potential antioxidant and antiproliferative agents.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"23 6","pages":"1-9"},"PeriodicalIF":0.3,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41244856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antonija Kezerle, Natalija Velić, D. Hasenay, D. Kovačević
{"title":"Lignocellulosic Materials as Dye Adsorbents: Adsorption of Methylene Blue and Congo Red on Brewers’ Spent Grain","authors":"Antonija Kezerle, Natalija Velić, D. Hasenay, D. Kovačević","doi":"10.5562/CCA3289","DOIUrl":"https://doi.org/10.5562/CCA3289","url":null,"abstract":"Brewers’ spent grain (BSG), a lignocellulosic waste material, was evaluated as a low-cost adsorbent for the removal of synthetic dyes methylene blue (MB) and Congo red (CR) from aqueous solutions in a batch process. Characterisation of the BSG was performed by chemical analysis, FTIR and SEM. The effects of contact time, initial dye concentration, adsorbent particle size, adsorbent concentration and pH on the adsorption process were investigated. High removal of both dyes ranging from 70 to over 90 % was achieved. It was shown that in both cases (MB and CR adsorption) the process could be interpreted in terms of Langmuir and Freundlich adsorption isotherms. The kinetics of the adsorption process was well described by the pseudo- second-order model. The results indicated the potential use of BSG as a low-cost adsorbent for MB and CR dye removal from aqueous solutions.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"53-64"},"PeriodicalIF":0.3,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3289","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49238918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}