Galactic Punctuated Equilibrium: How to Undermine Carter's Anthropic Argument in Astrobiology

We investigate a new strategy which can defeat the (in)famous Carter's "anthropic" argument against extraterrestrial life and intelligence. In contrast to those already considered by Wilson, Livio, and others, the present approach is based on relaxing hidden uniformitarian assumptions, considering instead a dynamical succession of evolutionary regimes governed by both global (Galaxy-wide) and local (planet- or planetary system-limited) regulation mechanisms. This is in accordance with recent developments in both astrophysics and evolutionary biology. Notably, our increased understanding of the nature of supernovae and gamma-ray bursts, as well as of strong coupling between the Solar System and the Galaxy on one hand, and the theories of "punctuated equilibria" of Eldredge and Gould and "macroevolutionary regimes" of Jablonski, Valentine, et al. on the other, are in full accordance with the regulation- mechanism picture. The application of this particular strategy highlights the limits of application of Carter's argument, and indicates that in the real universe its applicability conditions are not satisfied. We conclude that drawing far-reaching conclusions about the scarcity of extraterrestrial intelligence and the prospects of our efforts to detect it on the basis of this argument is unwarranted.Comment: 3 figures, 26 page

Snail meat: Significance and consumption

The consumption of snail meat goes back to prehistoric times. Different ancient nations had snails on their menu, but Helices culture as a productive activity was born as a Roman culture. Some of the most economically important edible species are: Helix aspersa (Mtiller) Helixpomatia (Linne), Helix iucorum (Linne), Helix aperta (Born), Eobania vermiculata (Miiller). Together with its tasie, snail meat has several advantages over others: quite low lipid rate and calorie values versus rich mineral, essential amino acid and fatty acid content. The composition of snail meat is presented. In addition, the composition of different snail species and the part analyzed (pedal mass and visceral mass) is presented. Also, the differences in composition according to the species (snail meat horse/chicken meat, beef, swine meat, fish meat) are presented. The French are the world's leading consumers of snails. !n France snails come to market in a variety of ways. Estimated consumption of snails in France is around 40 000 tones/year. Total French imports account for 25% of world imports. France is also the leading exporter of prepared snails, mainly sold as preserved snails and prepared dishes. Snail imports have been much higher than exports (65 tones exported in 2002. vs. 2.700 tones imported). Despite the large consumption, only 3% of snails in France come from production (farming). Italy is in second place in the world consumption of snails, and Spain and Germany are in the third and fourth place. The development of snails consumption in Italy is followed with the same amount of production of snails in the whole biological circle. In 2001, from 24,700 tons, 9,350 tons (37.8%) came from production, 6 00 tons (2.4%) came from nature, and 14,750 tons (59.70%) came from imports (frozen, fresh and prepared snails). In Serbia, at the beginning of 2005, we had over 400 registered farms for snail production

Analysis of the subunit composition and regulation of glutamine synthetase isoforms from Arabidopsis thalliana (L.) Heynh. и Lotus corniculatus L.

Глутамин-синтетаза (GS) каталише асимилацију амонијум-јона пореклом од редукције нитрата, фотореспирације, катаболизма аминокиселина, фиксације N2 код легуминоза и других метаболичких процеса код биљка. Код виших биљака, мала фамилија гена кодира различите цитосолне (GS1) изоформе, док један ген кодира изоформу локализовану у пластидима (GS2). Заједно са глутамат-синтазом (GOGAT), GS је део двоензимског циклуса одговорног за биосинтезу глутамата, који је донор амино-групе аминокиселинама у реакцијама каталисаним различитим трансаминазама. Стицање додатних сазнања о GS је од пресудног значаја за разумевање процеса асимилације азота код виших биљака, што може довести до боље ефикасности у коришћењу доступног азота и смањеној употреби вештачких ђубрива. У презентованом истраживању испитивана је структура и регулација GS изоформи из две модел-биљке, Arabidopsis thaliana (L.) Heynh и Lotus corniculatus L. Један од циљева био је испитивање могућности различитих GS1 протеина A. thaliana, чији геном кодира пет GS1 субјединица (GLN1;1-1,5), да формирају хетеромере. Како би се испитао субјединични састав GS1 изоформи A. thaliana, упоређени су електрофоретски профили GS изоформи различитих GS1 SALK и SAIL knockout мутаната. Закључено је да GLN1;1 и GLN1;3, као и GLN1;2 и GLN1;3, а могуће и GLN1;1 и GLN1;2 субјединице могу да се комбинују у свим стехиометријским односима формирајући функционалне декамерне ензиме. Поред тога, код knockout мутаната у GLN1;2 и GLN1;3 детектована је повишена количина GLN1;1 транскрипата што упућује да GLN1;1 делом компензује недостајуће изоформе. Други циљ овог истраживања био је испитивање регулације експресије GS и GOGAT гена A. thaliana биљним регулаторима растења: кинетином, абсцисинском киселином, гиберелинском киселином и 2,4-дихлорфеноксиацетатом. Експресија GS и GOGAT гена је диференцијално регулисана регулаторима растења у листу и корену, а добијени обрасци експресије упућују на могући физиолошки контекст хормоналне регулације ових гена током развића биљке и као одговору на услове средине. Трећи циљ је био испитивање хормезе индуковане фосфинотрицином (PPT) код звездана (L. corniculatus). PPT је инхибитор GS који је пронашао примену као неселективни хербицид. Инхибиција GS у биљци доводи до нагомилавања амонијака, недостатка глутамина и коначно, до смрти. Утврђено је да биљке L. corniculatus третиране ширим опсегом концентрација PPT-а, показују двофазни одговор који обухвата стимулацију продукције биомасе при концентрацијама нижим од 50 μM, и инхибицију раста и смрт биљке при вишим концентрацијама. Стимулација раста ниским концентрацијама PPT-а је последица активације GS2 изоформе, док је инхибиција раста и смрт биљке при високим концентрацијама хербицида проузрокована инхибицијом GS1 и GS2 изоформи. Предложен је детаљан молекулски механизам концентрационо-зависне интеракције GS холоензима са PPT-ом, који је у складу са експерименталним и литературним подацима.Glutamine synthetase (GS) is the key enzyme involved in the assimilation of ammonia derived from nitrate reduction, photorespiration, amino acid catabolism, N2 fixation in legumes, and other metabolic processes in plants. A small gene family encodes for different cytosolic (GS1) isoforms in higher plants, while a single gene encodes for the plastidic isoform (GS2). GS operates with glutamate synthаse (GOGAT) in a two enzyme cycle. The net outcome of this cycle is the production of glutamate, which, through the action of aminotransferases, is used to synthesize other amino acids. Gaining further knowledge about GS is essential for understanding nitrogen assimilation in higher plants, which can lead to better nitrogen use efficiency and lowering of fertilizer input. The structure and regulation of GS isoforms from two model plants, Arabidopsis thaliana (L.) Heynh and Lotus corniculatus L. were investigated in the presented study. Since the A. thaliana genome encodes five GS1 subunits (GLN1;1-1,5), one of the objectives was to investigate whether different GS1 proteins from this plant are able to form heteromeric enzymes. In order to identify the subunit composition of A. thaliana GS1 isoforms, electrophoretic profiles of GS isoforms from GS1 SALK and SAIL knockout mutants were compared. It was concluded that GLN1;1 and GLN1;3, as well as GLN1;2 and GLN1;3 and possibly GLN1;1 and GLN1;2 are able to form functional heterodecamers in all stoichiometric proportions. Furthermore, in the knockout mutants lacking GLN1;2 and GLN1;3, higher GLN1;1 transcript levels were found implicating that GLN1;1, at least in part, compensates for the missing isoforms. The second objective of this study was to investigate the regulation of expression of A. thaliana GS and GOGAT genes by plant growth regulators: kinetin, abscisic acid, giberelic acid and 2,4-dichlorophenoxyacetic acid. The expression of GS and GOGAT genes is differentially regulated by growth regulators in the leaf and root. The observed patterns of expression provide insights into the hormonal regulation of these genes during development and as response to environmental cues. The third objective was to investigate phosphinothricin (PPT) induced hormesis in L. corniculatus. PPT is a potent GS inhibitor used as a non selective post emergence herbicide. GS inhibition in plants causes ammonia accumulation, glutamine depletion and eventually death. However, the growth response of L. corniculatus plants immersed in solutions with a broad range of PPT concentrations is biphasic, with pronounced stimulating effect on biomass production at concentrations ≤ 50 μM and growth inhibition at higher concentrations. The growth stimulation at low PPT concentrations is a result of activation of GS2, while the growth suppression is caused by inhibition of both GS1 and GS2 at higher PPT concentrations. A detailed molecular mechanism of concentration-dependent interaction of PPT with the GS holoenzymes from L. corniculatus is proposed. The mechanism is in concurrence with all experimental and literature data

Changes in Soil Erosion Intensity Caused by Land Use and Demographic Changes in the Jablanica River Basin, Serbia

The aim of this research is to determine the change in the spatial distribution of erosion intensity in the territory of the Jablanica River Basin in the period 1971-2016 caused by land use and demographic changes. The Erosion Potential Method (EPM) was used to quantify changes in erosion intensity and to estimate the total annual sediment yield. The research results show that the value of the erosion coefficient decreased from 0.432 in 1971 to 0.360 in 2016. Specific annual gross erosion in the Jablanica River Basin was 654.41 m(3)/km(2)/year in 1971, while in 2016 it was 472.03 m(3)/km(2)/year. The analysis of proportional changes was used to determine demographic changes and land use patterns in the basin area. In terms of the scale and intensity of the erosion process, three types and one sub-type of population dynamics of settlements and land use changes were distinguished, respectively: progressive, stagnant, regressive and dominant regressive. It was concluded that the results show the significance of demographic and land use changes in the control of the intensity of erosion. The Soil Erosion Map may be useful to planners and land use managers to take appropriate decisions for soil conservation in the basin

Differential regulation of GS-GOGAT gene expression by plant growth regulators in Arabidopsis seedlings

Primary and secondary ammonium assimilation is catalyzed by the glutamine synthetase-glutamate synthase (GS-GOGAT) pathway in plants. The Arabidopsis genome contains five cytosolic GS1 genes (GLN1;1 - GLN1;5), one nuclear gene for chloroplastic GS2 isoform (GLN2), two Fd-GOGAT genes (GLU1 and GLU2) and a GLT1 gene coding for NADH-GOGAT. Even though the regulation of GS and GOGAT isoforms has been extensively studied in response to various environmental and metabolic cues in many plant species, little is known about the effects of phytohormones on their regulation. The objective of this study was to investigate the impact of representative plant growth regulators, kinetin (KIN), abscisic acid (ABA), gibberellic acid (GA3) and 2,4-dichlorophenoxyacetic acid (2,4-D), on the expression of A. thaliana GS and GOGAT genes. The obtained results indicate that GS and GOGAT genes are differentially regulated by growth regulators in shoots and roots. KIN and 2,4-D repressed GS and GOGAT expression in roots, with little effect on transcript levels in shoots. KIN affected all tested genes; 2,4-D was apparently more selective and less potent. ABA induced the expression of GLN1;1 and GLU2 in whole seedlings, while GA3 enhanced the expression of all tested genes in shoots, except GLU2. The observed expression patterns are discussed in relation to physiological roles of investigated plant growth regulators and N-assimilating enzymes

In vitro production of chlorogenic acid in culture of transformed Cichorium intybus L.: Plants

Chicory (Cichorium intybus L.) is traditionally recognized for its antiinflammatory, antimicrobial, anticancer and nutritive properties. Among active secondary metabolites detected in chicory, the most important are sesquiterpene lactones and phenolics, including chlorogenic acid (CA). Hereby we have analyzed the content of CA in previously obtained Agrobacterium rhizogenes - transformed chicory hairy root cultures and transformed regenerants. Among three analyzed hairy root clones, clone 13 had exceptionally high biomass production, so the amount of CA in this culture was the highest, e.g. 400 times higher in comparison to the untransformed root culture. Since the roots spontaneously regenerated, the system was upgraded to allow the comparison of CA content not only among the clones, but also between different developmental phases of the regenerants (vegetative vs. flowering plants) and their organs (roots vs. leaves). It was shown that the CA production varies from clone to clone, and also depends on the phenophase of the clone. In the rosette stage of clones 13 and 36, the highest amount of CA was detected in roots, while the same clones in the flowering stage had significantly lower CA content. The clone 35 in the vegetative phase produced the lowest amounts of CA. However, in the flowering stage the roots of clone 35 produced the highest CA amount. Among the regenerants, the clone 13 had the fastest growth, and hence the best CA production. The current paper presents for the first time the CA content in transformed chicory regenerants. The obtained results suggest that the culture of transformed chicory plants can be equally good source of CA as liquid hairy root culture.U ovom radu je, nakon transformacije cikorije pomoću Agrobacterium rhizogenes i dobijanja kulture transformisanih korenova i transformisanih regeneranata, analiziran sadržaj hlorogene kiseline (HK) u datim kulturama. Od tri ispitivana klona transformisanih korenova cikorije, klon 13 se odlikovao izuzetno visokom produkcijom biomase, pa je i količina HK u datoj kulturi bila najviša, tj. 400 puta veća od količine u kulturi netransformisanih korenova. Zahvaljujući spontanoj regeneraciji dati sistem je unapređen, što je omogućilo praćenje promene u nivou HK ne samo između klonova, već i između određenih stadijuma razvića klonova (rozete i biljke u cvetu) i njihovih delova (koren i list). Pokazano je da produkcija HK zavisi kako od klona, tako i od fenofaze u kojoj se dati klon nalazi. U fazi rozete klonova 13 i 36 najveća količina HK detektovana je u korenovima, dok je u fazi cvetanja ovih klonova izmeren znatno niži nivo. Klon 35 je u fazi rozete produkovao najmanju količinu HK, dok je u fazi cvetanja u korenovima datog klona izmeren najviši sadržaj HK. Među regenerantima klon 13 je najbrže rastao a samim tim i najviše produkovao HK. U ovom radu po prvi put je analiziran sadržaj HK u transformisanim regenerantima cikorije, a dobijeni rezultati ukazuju da je kultura transformisanih biljaka cikorije podjednako dobar izvor HK kao i tečna kultura transformisanih korenova.Projekat ministarstva br. OI 17302

DUF1070 as a signature domain of a subclass of arabinogalactan peptides

Over 20% of all protein domains are currently annotated as "domains of unknown function" or DUFs. In a recently identified Centaurium erythraea arabinogalactan peptide, CeAGP3 (AGN92423), a conserved DUF1070 domain was found. Since identifying functions for DUFs is important in systems biology, we have analyzed the distribution and structure of DUF1070 domain (pfam06376) using a set of bioinformatics tools. There are 271 publically available DUF1070 members from 25 diverse families of vascular plants, and most are short sequences (50-100 aa). The N-terminal signal peptide (Nsp) was found in almost all complete sequences. In 233 sequences, at least two noncontiguous prolines were found as clustered dipeptides predicted to be hydroxylated and glycosylated with type II arabino-3,6-galactans, thus representing AG-II glycomodules. In addition, 35 sequences contained a region rich in basic residues (basic linker, BL). The N-terminal part of the DUF1070 domain is comprised of (part of) AG-II and/or BL, while the highly conserved C-terminus is a region of 26 aa, termed SH26. In 212 sequences, SH26 was a typical glycosylphosphatidylinositol lipid anchor signal peptide (GPIsp), but in 83 cases GPIsp was not predicted due to software constraints. In sequences where both Nsp and GPIsp were predicted, the length of mature peptides could be calculated, and it was 10-16 aa. Our analysis suggests that DUF1070 members are arabinogalactan (AG) peptides, of which the majority are GPI-anchored. DUF1070 is the only conserved domain found in classical arabinogalactan proteins and AG peptides. The SH26 region can be used for mining and annotation of AG peptides.Archives of Biological Sciences (2016), 68(4): 737-74

Phenotypic and Genetic Variation of an Interspecific Centaurium Hybrid (Gentianaceae) and Its Parental Species.

Interspecific hybridization is one of the major actuators of evolutionary changes in plants. As the result of allopolyploid hybridization, offspring may gain different ploidy levels in comparison to parental species, which can provide them instant reproductive isolation. Two tetraploid sister species, Centaurium erythraea and C. littorale, readily cross-fertilize, resulting in hybrids of various ploidy. In northern Serbia, two stable populations of a hexaploid taxon C. pannonicum have been documented. It has been proposed previously that this taxon emerged after an interspecific hybridization event between two tetraploid sister-species: C. erythraea and C. littorale subsp. compressum. The existing populations of the hybridogenic taxon, as well as neighboring populations of the two parental taxa were here characterized by both morphometrics and molecular markers (EST-SSR and trnL-F). Three leaf and two flower characteristics were found to be informative in delimitation of the parental taxa and in their discernment from hybrid individuals, the latter having intermediate values. Eight microsatellite markers were found to have good ability to distinguish studied taxa, placing C. pannonicum in closer relationship with C. erythraea. Conversely, trnL-F plastid marker nominated C. littorale subsp. compressum to be the donor of the C. pannonicum plastid DNA. Reproductive isolation of the hexaploid hybrid individuals from the parental species should be examined as the next logical step in describing the new species

Supplementary data for the article: Stupar, S.; Dragićević, M.; Tešević, V.; Stanković-Jeremić, J.; Maksimović, V.; Ćosić, T.; Devrnja, N.; Tubić, L.; Cingel, A.; Vinterhalter, B.; Ninković, S.; Savić, J. Transcriptome Profiling of the Potato Exposed to French Marigold Essential Oil with a Special Emphasis on Leaf Starch Metabolism and Defense against Colorado Potato Beetle. Plants 2021, 10 (1), 172. https://doi.org/10.3390/plants10010172.

Supplementary material for: [https://doi.org/10.3390/plants10010172]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4499

Effects of C60 Fullerene on Thioacetamide-Induced Rat Liver Toxicity and Gut Microbiome Changes

Thioacetamide (TAA) is widely used to study liver toxicity accompanied by oxidative stress, inflammation, cell necrosis, fibrosis, cholestasis, and hepatocellular carcinoma. As an efficient free radical’s scavenger, C60 fullerene is considered a potential liver-protective agent in chemically-induced liver injury. In the present work, we examined the hepatoprotective effects of two C60 doses dissolved in virgin olive oil against TAA-induced hepatotoxicity in rats. We showed that TAA-induced increase in liver oxidative stress, judged by the changes in the activities of SOD, CAT, GPx, GR, GST, the content of GSH and 4-HNE, and expression of HO-1, MnSOD, and CuZnSOD, was more effectively ameliorated with a lower C60 dose. Improvement in liver antioxidative status caused by C60 was accompanied by a decrease in liver HMGB1 expression and an increase in nuclear Nrf2/NF-κB p65 ratio, suggesting a reduction in inflammation, necrosis and fibrosis. These results were in accordance with liver histology analysis, liver comet assay, and changes in serum levels of ALT, AST, and AP. The changes observed in gut microbiome support detrimental effects of TAA and hepatoprotective effects of low C60 dose. Less protective effects of a higher C60 dose could be a consequence of its enhanced aggregation and related pro-oxidant role