2 research outputs found
Historical Transition of a Farming System towards Industrialization: A Danish Agricultural Case Study Comparing Sustainability in the 1840s and 2019
No full textA Danish pre-industrial farming system is reconstructed and compared to its modern industrialized farming system equivalent to evaluate agricultural performance in a sustainability perspective. The investigated Danish farm system and its contributing elements have undergone significant transformations. The intensity of contemporary agriculture shows that high productivity levels have been achieved by increasing the input of energy using modern machinery. At the same time, the energy efficiency (calculations based on energetic indicators) diminishes over time as the degree of dependence on fossil fuels increases. The results from this study show significant changes in the farming system, specifically inputs from agricultural land use, livestock, and energy systems. From being highly circular, the system changed to being a clear linear farming system with highly increased productivity but less efficient at the same time, questioning the relationship between productivity and efficiency and resource utilization in modern farming systems. Through utilizing an agroecological historical approach by comparing system performance over time, the results offer opportunities to explore how agricultural farming systems evolve over time and help to describe the complexity of the system level in a sustainability perspective
Bakteri ribosoomide uurimus keemilise modifitseerimise meetoditega
No full textVäitekirja elektrooniline versioon ei sisalda publikatsioone.Ribosoom on suur makromolekulaarne kompleks, mis kodeerib päriliku informatsiooni valgulisse olemusse. Eeltuumsete organsimide ribosoom koosneb kaheks alamühikust, väikesest (30S) ja suurest (50S) alamühikust. Ribosoomi kahte alamühikut hoiavad koos ~ 30 erinevat ühendust, mis on jagatud 12 silla (B1a-B8) vahel. Väike alamühik koosneb ühest RNA molekulist (16S rRNA, 1542 nukleotiidi) ja 21-st ribosoomi valgust (S1-S21). Ribosoomi suur alamühik koosneb kahest RNA molekulist (5S rRNA, 120 nukleotiidi ja 23S rRNA, 2904 nukleotiidi) ja 33-st ribosoomi valgust (L1-L36).
Minu töös uuritakse ribosomaalse RNA keemiliste positsioonide olulisust ribosoomi kahe alamühiku omavahelisel seonumisel. Keemilise modifitseerimise meetodit kasutades detekteerisime 16S rRNA-s kuus positsiooni (A702, A1418, A1483, U793, U1414 ja U1495), millede modifitseerimine takistab alamühikute assotseerumist. Detekteeritud positsioonid paiknevad tuntud alamühikute vahelistes sildades. Seega alamühikute assotsiatsioonil mängivad olulist rolli sillad B2a (U1495), B2b(U793), B3 (A1418, A1483, U1414) ja B7a (A702).
Lisaks sellele töötasime välja meetodi, millega saab uurida RNA suhkur-fosfaat selgroo interaktsioone 23S rRNA-s. Välja töötatud meetodit on võimalik kasutada RNA suhkur-fosfaat selgroo interaktsioonide uurimiseks, substraatide sidumiskohtade määramiseks ja individuaalsete positsioonide mõju määramiseks valgusünteesi erinevates etappides.
Kolmandas töös uuritakse ribosoomi valkude võimet välja vahetuda ja selle tulemusena taastada keemiliselt kahjustatud ribosoomide funktsioon. Ribosoomis välja vahetuvate valkude kindlaks tegemiseks, me kasutasime kahte in vitro meetodit, nii radioaktiivset märgistamist kui ka raskete isotoopide eristamise meetodit. Ribosoomi valgud S2, L1, L7/12, L9, L10, L11 ja L33 on kõige kergemini vahetuvad r-valgud. Seega, meie tulemused näitavad, et kahjustatud ribosoome on võimalik parandada valkude asendamise teel.The ribosome is a macromolecular assembly that is responsible for protein biosynthesis following genetic instructions in all organisms. The prokaryotic ribosome contains about two-thirds RNA and one-third protein and consists of two subunits, the larger (50S) of which is approximately twice the molecular weight of the smaller (30S). Prokaryotic ribosomes contain ~54 different proteins, 23S rRNA, 16S rRNA, and 5S rRNA.
Two ribosomal subunits are held together by more than 30 individual intersubunit interactions spread among 12 bridges (B1-B8). Using modification interference approach we were able to identify 6 essential 16S rRNA positions for subunit association. Modification of the N1 position of A702, A1418, and A1483 with DMS, and of the N3 position of U793, U1414, and U1495 with CMCT in 30S subunits strongly interferes with 70S ribosome formation. Five of these positions localize into previously recognized intersubunit bridges, namely, B2a (U1495), B2b (U793), B3 (A1483; A1418), and B7a (A702). These four intersubunit bridges are essential for reassociation of the 70S ribosome, thus forming the functional core of the intersubunit contacts.
In order to study RNA backbone interactions in the ribosome, we combined different assays like in vitro T7 transcription, in vitro 50S reconstitution and primer extension to generate a reliable approach to study RNA backbone interactions of the large ribosomal subunit by using phosphorothioate approach. This phosphorothioate-substitution approach is suitable for footprinting of various ligand-ribosome complexes and for functional studies in the modification interference assay.
In addition, because the ribosome is made of many individual proteins, we studied the ability of ribosomal proteins to exchange and restore the function of damaged ribosomes. Incubation of chemically inactivated ribosomes with total ribosomal proteins led to reactivation of translational activity. Ribosomal proteins S1, S2, L1, L7/12, L9, L10, L11 and L33 are among the most readily exchangeable proteins. The results show that the damaged ribosomes can be repaired by mean of protein exchange
