Engineering Membranes in Escherichia coli: The Magnetosome, LemA Protein Family and Outer Membrane Vesicles

Magnetosomes are membranous organelles found in magnetotactic bacteria (MTB). The organelle consist of ferromagnetic crystals housed within a lipid bilayer chained together by an actin-like filament and allows MTB to orient within magnetic fields. The genetic information required to produce these organelles has been linked to four different operons, encoding for 30 genes. These membranous organelles and the magnetic minerals housed within have various biotechnological applications, therefore enhanced recombinant production of such structures in a model organism holds significant potential. The research described in this thesis is focuses on the production of recombinant magnetosomes in the model organism Escherichia coli. Cloning the genes involved in the generation of the organelle individually or in various combinations resulted in the construction of over 100 different plasmids, compatible with the model organism. SDS-PAGE and electron microscopy analysis was used to characterise E. coli cells harbouring these constructs. The observation of electron dense particles, arranged in a chain structure, show that magnetosome generation in the model organism is possible, but is highly dependent on the growth conditions used. The need for specific growth conditions is later backed up by the analysis of the maturation of the cytochrome c proteins involved in magnetosome biomineralisation, which can only be correctly processed under certain conditions. Individual production of two different magnetosome proteins, MamQ or MamY, allowed the generation of various membranous structures in E. coli observed in 48.9% and 56.2% of the whole population of cells respectively. Combinations of these with MamI, MamL or MamB in a variety of combinations led to a variation in the phenotype observed. Bioinformatics analysis of MamQ led to the discovery of a novel membrane restructuring protein family, the LemA protein family, present in a broad range of bacteria. Four different LemA proteins from Bacillus megaterium, Clostridium kluyveri, Brucella melitensis or Pseudomonas aeruginosa were then produced in E. coli and the analysis of the resulting strains revealed the presence of novel intracellular membranous structures which vary in size, form and localisation. Furthermore, when attempts were made to target these proteins for the modification of the outer membrane, a mechanism for increased outer membrane vesicle generation was serendipitously discovered and different effects of these proteins were once again observed. Together, the results described shows good evidence for recombinant magnetosome production in E. coli and opens a new avenue of membrane engineering in this commonly used organism. Such membranous structures have various biotechnological applications, such as enhanced metabolic engineering potential or specialised lipid vesicle production

Vertikaliosios skrandžio rezekcijos dešimties metų rezultatai: sisteminė literatūros apžvalga

Introduction. Sleeve gastrectomy is currently the most popular surgical treatment for obesity worldwide. However, there is still a lack of data on long-term outcomes of this procedure. The objective of this study was to review and analyze the scientific literature and evaluate the long-term (10 years and beyond) results of sleeve gastrectomy for the surgical treatment of obesity. Methods. A literature search was conducted using the PubMed search engine, resulting in 1 443 publications on the long-term results of sleeve gastrectomy for obesity. After applying search criteria and selecting articles by title and abstract, 7 results were included in the systematic review. Results. The included studies involved 2 399 patients after sleeve gastrectomy, with an average age of 41.8 years and 1 577 (65.7%) of all patients being women. The mean preoperative body mass index of the patients in the selected publications was 45.1 kg/m2. Long-term (10 years and beyond) weight loss outcomes were assessed in terms of excess body weight loss. Among the studies, the average excess body weight loss achieved was 54.2%, with a maximum of 70.5% and a minimum of 36%. Arterial hypertension remission was achieved in 23.6%, obstructive sleep apnea remission was achieved in 62.2%, type II diabetes remission was achieved in 54.4%, and dyslipidemia remission was achieved in 42.5% of patients. Conclusion. Sleeve gastrectomy provides a stable reduction in excess body weight and control of comorbidities over 10 years. However, more data on the long-term results of sleeve gastrectomy are needed to compare it with other surgical approaches in the treatment of obesity. Įvadas. Vertikalioji skrandžio rezekcija šiandien pasaulyje yra populiariausias chirurginis nutukimo gydymo būdas. 2020 m. vien JAV atlikta 199 tūkst. bariatrinių operacijų, iš jų kiek daugiau negu 60 proc. sudarė vertikalioji skandžio rezekcija [1]. Operacijų skaičius kasmet didėja, tačiau vis dar trūksta duomenų apie ilgalaikius gydymo rezultatus. Darbo tikslas – apžvelgti ir įvertinti ilgalaikius (10 m. ir vėlesnius) vertikaliosios skrandžio rezekcijos rezultatus gydant nutukimą. Metodai. Mokslinės literatūros paieška atlikta naudojant PubMed paieškos sistemą. Rasti 1 443 straipsniai, kuriuose pateikiami vertikaliosios skrandžio rezekcijos ilgalaikiai rezultatai. Atrankos kriterijus atitiko 7 publikacijos, jos analizuotos išsamiau. Rezultatai. Atlikus mokslinės literatūros paiešką, atrinkti 7 moksliniai straipsniai. Analizuotose publikacijose iš viso tirti 2 399 pacientai, kuriems atlikta vertikalioji skrandžio rezekcija. 1 622 pacientų duomenys vertinti praėjus 10 m. ar vėlesniu laikotarpiu. Stebėtiems pacientams buvo vidutiniškai 41,8 m. Analizuoti 1 577 moterų duomenys (65,7 proc. visų pacientų). Vidutinis pacientų kūno masės indeksas prieš operaciją siekė 45,1 kg/m2. Ilgalaikiai (10 m. ir vėlesni) svorio metimo rezultatai vertinti atsižvelgiant į perteklinį kūno masės sumažėjimą. Perteklinė kūno masė vidutiniškai mažėjo 54,2 proc. (daugiausia – 70,5 proc., mažiausia – 36 proc.). Atlikus operaciją, arterinės hipertenzijos, obstrukcinės miego apnėjos, II tipo cukrinio diabeto ir dislipidemijos remisija buvo pasiekta atitinkamai 23,6 proc., 62,2 proc., 54,4 proc. ir 42,5 proc. pacientų. Išvados. Vertikalioji skrandžio rezekcija 10 m. laikotarpiu užtikrina stabilų perteklinės kūno masės mažėjimą ir gretutinių ligų kontrolę. Vis dėlto nėra daug duomenų apie vėlyvuosius vertikaliosios skrandžio rezekcijos rezultatus, kurie leistų šį metodą lyginti su kitais chirurginiais nutukimo gydymo metodais

Priešoperacinių veiksnių įtaka prognozuojant kūno masės sumažėjimą praėjus penkeriems metams po nutukimo gydymo skrandžio apjuosimo reguliuojama juosta operacijos: perspektyvusis atsitiktinių imčių tyrimas

Background Laparoscopic adjustable gastric banding (LAGB) is used as a bariatric procedure for more than 30 years, but there is still insuf­ficient data regarding postoperative weight-loss predicting factors.Objective We carried out a prospective randomized study to compare two different bands (SAGB and Minimizer Extra) and aimed to find weight-loss predicting factors.Methods A total of 103 morbidly obese patients underwent LAGB from January 2009 to January 2010. The SAGB was used in 49 and MiniMizer Extra in 54 patients. Weight loss was evaluated after 1 and 5 years. Factors which significantly correlated with per­centage excess weight loss (%EWL) were used to build predicting regression models.Results The mean patient age was 45.9 ± 11.7 years, and mean preoperative body mass index (BMI) was 47.5 ± 7.3 kg/m2. A total of 90 (87.3%) patients completed the 5-year follow-up. The mean overall excess weight loss after 5 years was 47.3 ± 29.7%, and there was no difference between SAGB and MiniMizer bands (47.3% vs 50.3%; p = 0.14). After 1 year, BMI ≤ 47 MiniMizer, pa­tients demonstrated better weight loss results. %EWL was also significantly greater in >40-year-old MiniMizer group patients (p =0.012) and remained significantly higher after 5 years (p = 0.035).Conclusions In > 40-year-old patient group better %EWL can be achieved by using MiniMizer Extra bands compared to SAGB. The con­structed prognostic models could be used to predict %EWL after application of SAGB and MiniMizer bands.Įvadas Skrandžio apjuosimo reguliuojama juosta operacija klinikinėje praktikoje atliekama daugiau nei 30 metų. Jos efektyvumą patvirtino daugelis studijų, tačiau nepakanka tyrimų, kuriuose būtų analizuojami priešoperaciniai kūno masės pokyčių prog­nostiniai veiksniai.Tikslas Nustatyti priešoperacinius prognostinius veiksnius, palyginant dvi skirtingas skrandį apjuosiančias reguliuojamas juostas (SAGB ir Minimizer Extra), siekiant geresnių kūno masės mažėjimo rezultatų.Ligoniai ir metodai Nuo 2009 m. sausio 1 d. iki 2010 m. sausio 31 d. į tyrimą buvo įtraukti 103 morbidiniu nutukimu sergantys ligoniai. SAGB juosta naudota 49 ligoniams, MiniMizer Extra – 54 pacientams. Ligoniai pakartotinai ištirti praėjus 1 ir 5 metams. Iš veiksnių, koreliuojančių su procentiniu perteklinės kūno masės sumažėjimu (%PKMS), sudarėme prognostinius regresijos modelius.Rezultatai Vidutinis ligonių amžius buvo 46,1 ± 11,5 metų. Vidutinis kūno masės indeksas (KMI) – 47,5 ± 7,3 kg/m2. Po 5 metų pakarto­tinai ištirta 90 (87,3%) ligonių. Vidutinis %PKMS po 5 metų buvo 47,3 ± 29,7%, lyginant SAGB ir MiniMizer juostas statistiškai reikšmingo skirtumo (44,1 ± 31,9 ir 50,3 ± 27,6; p = 0,14) nebuvo. Pacientų amžius, priešoperacinė juosmens apimtis ir KMI statistiškai reikšmingai koreliavo su %PKMS.Lyginant SAGB ir Minimizer juostas, po 1 metų %PKMS buvo statistiškai reikšmingai didesnis mažiau nutukusių (KMI ≤ 47 kg/m2) MiniMizer Extra pacientų grupėje. Praėjus 1 ir 5 metams, %PKMS buvo statistiškai reikšmingai didesnis vyresnių nei 40 metų MiniMizer Extra ligonių grupėje.Išvados Didesnis pooperacinis %PKMS gali būti pasiektas vyresniems nei 40 metų pacientams, skrandžio apjuosimo reguliuojama juosta operacijai naudojant MiniMizer Extra juostą. Sudaryti prognostiniai modeliai leidžia numatyti %PKMS naudojant SAGB ir MiniMizer juostas

Vėlyvieji laparoskopinės vertikalios skrandžio rezekcijos gydymo rezultatai

ObjectiveThe aim of the study was to review long-term results in the morbidly of obese patients undergoing laparoscopic sleeve gastrectomy.Materials and methodsSeveral databases were searched, including Medline, Current Contents and Cochrane Library. All sleeve gastrectomy studies published until 2015 with long-term results (5 years or longer) were reviewed.ResultsTwenty studies, presenting 5-year or longer results after sleeve gastrectomy, were included in our analysis. A total of 4354 patients after laparoscopic sleeve gastrectomy were included in the selected studies, 1536 of whom were followed for at least 5 years. Their mean age was 37.9 years. Their mean preoperative body mass index was 46.3 kg/m2. The mean percentage of excess weight loss was 59.9 %, 58.5 %, 56.6 % and 56.4 % at 5, 6, 7 and 8 years, respectively. The overall complication rate was 6.47 %, and the 30-day mortality rate was 0.19 %. There was a remission or improvement of diabetes observed in 71.4 %, arterial hypertension in 64.4 %, dyslipidemia in 50.1 %, obstructive sleep apnea in 86.9 %, gastroesophageal reflux disease in 41.8 % and degenerative joint diseases in 83.9 % of the patients 5 years after sleeve gastrectomy. The mean BAROS scale score five years after laparoscopic sleeve gastrectomy was 6, which is equivalent to a very good result.ConclusionsOur study suggests that laparoscopic sleeve gastrectomy is a safe and effective bariatric surgery modality resulting in the good quality of life and a significant resolution of obesity-related comorbidities. Moreover, the excess weight loss is stableafter 5 years.Darbo tikslasRemiantis literatūros duomenimis išanalizuoti vėlyvuosius (≥5 metų) laparoskopinės vertikalios skrandžio rezekcijos rezultatus gydant morbidinį nutukimą.Tiriamoji medžiaga ir metodaiPublikacijų paieška atlikta „Medline“, „Current Contents“ ir „Cochrane Library“ duomenų bazėse. Apžvelgtos visos laparoskopinės vertikalios skrandžio rezekcijos 5 metų ir vėlesnius rezultatus pateikiančios publikacijos, paskelbtos iki 2015 m. sausio 1 dienos.RezultataiAtlikus literatūros šaltinių paiešką, rasta 20 publikacijų, pateikiančių 5 metų ir vėlesnius vertikalios skrandžio rezekcijos rezultatus. Įtrauktose studijose tirti 4354 ligoniai, iš kurių 1536 buvo stebėti 5 metus ir ilgiau. Tiriamųjų amžiaus vidurkis buvo 37,9 metai. Vidutinis priešoperacinis KMI buvo 46,3 kg/m2. Vidutinis procentinis perteklinės kūno masės netekimas po 5, 6, 7 ir 8 metų atitinkamai buvo 59,9 %, 58,5 %, 56,6 % ir 56,4 %. Bendras komplikacijų dažnis – 6,47 %, o pooperacinis 30 dienų mirštamumas – 0,19 %. Po 5 metų nustatyta gretutinių ligų remisija ar pagerėjimas: antro tipo cukrinio diabeto – 71,4 %, arterinės hipertenzijos – 61,4 %, dislipidemijos – 50,1 %, miego apnėjos – 86,9 %, gastroezofaginio refliukso ligos – 41,8 %, degeneracinių sąnarių ligų – 83,9 % ligonių. Vidutinis BAROS skalės balų skaičius praėjus 5 metams po vertikalios skrandžio rezekcijos buvo 6, tai atitinka labai gerus rezultatus.IšvadosLaparoskopinė vertikali skrandžio rezekcija yra efektyvi ir saugi nutukimo gydymo operacija, pasižyminti gera pooperacinegyvenimo kokybe ir gretutinių ligų kontrole, o perteklinės masės netekimas 5 metų laikotarpiu yra ženklus ir stabilus

Effect of metabolosome encapsulation peptides on enzyme activity, co-aggregation, incorporation and bacterial microcompartment formation

Metabolosomes, catabolic bacterial microcompartments, are proteinaceous organelles that are associated with the breakdown of metabolites such as propanediol and ethanolamine. They are composed of an outer multi-component protein shell that encases a specific metabolic pathway. Protein cargo found within BMCs is directed by the presence of an encapsulation peptide that appears to trigger aggregation prior to the formation of the outer shell. We investigated the effect of three distinct encapsulation peptides on foreign cargo in a recombinant BMC system. Our data demonstrate that these peptides cause variation with respect to enzyme activity and protein aggregation. We observed that the level of protein aggregation generally correlates with the size of metabolosomes, while in the absence of cargo BMCs self-assemble into smaller compartments. The results agree with a flexible model for BMC formation based around the ability of the BMC shell to associate with an aggregate formed due to the interaction of encapsulation peptides

Differential temporal release and lipoprotein loading in B. thetaiotaomicron bacterial extracellular vesicles

Bacterial extracellular vesicles (BEVs) contribute to stress responses, quorum sensing, biofilm formation and interspecies and interkingdom communication. However, the factors that regulate their release and heterogeneity are not well understood. We set out to investigate these factors in the common gut commensal Bacteroides thetaiotaomicron by studying BEV release throughout their growth cycle. Utilising a range of methods, we demonstrate that vesicles released at different stages of growth have significantly different composition, with early vesicles enriched in specifically released outer membrane vesicles (OMVs) containing a larger proportion of lipoproteins, while late phase BEVs primarily contain lytic vesicles with enrichment of cytoplasmic proteins. Furthermore, we demonstrate that lipoproteins containing a negatively charged signal peptide are preferentially incorporated in OMVs. We use this observation to predict all Bacteroides thetaiotaomicron OMV enriched lipoproteins and analyse their function. Overall, our findings highlight the need to understand media composition and BEV release dynamics prior to functional characterisation and define the theoretical functional capacity of Bacteroides thetaiotaomicron OMVs

Extracellular vesicles produced by the human gut commensal bacterium Bacteroides thetaiotaomicron elicit anti-inflammatory responses from innate immune cells

Bacterial extracellular vesicles (BEVs) produced by gut commensal bacteria have been proposed to play an important role in maintaining host homeostasis via interactions with the immune system. Details of the mediators and pathways of BEV-immune cell interactions are however incomplete. In this study, we provide evidence for the anti-inflammatory and immunomodulatory properties of extracellular vesicles produced by the prominent human gut commensal bacterium Bacteroides thetaiotaomicron (Bt BEVs) and identify the molecular mechanisms underlying their interaction with innate immune cells. Administration of Bt BEVs to mice treated with colitis-inducing dextran sodium sulfate (DSS) ameliorates the symptoms of intestinal inflammation, improving survival rate and reducing weight loss and disease activity index scores, in association with upregulation of IL-10 production in colonic tissue and in splenocytes. Pre-treatment (conditioning) of murine bone marrow derived monocytes (BMDM) with Bt BEVs resulted in higher ratio of IL-10/TNFα production after an LPS challenge when compared to LPS pre-conditioned or non-conditioned BMDM. Using the THP-1 monocytic cell line the interactions between Bt BEVs and monocytes/macrophages were shown to be mediated primarily by TLR2. Histone (H3K4me1) methylation analysis showed that Bt BEVs induced epigenetic reprogramming which persisted after infectious challenge, as revealed by increased levels of H3K4me1 in Bt BEV-conditioned LPS-challenged BMDM. Collectively, our findings highlight the important role of Bt BEVs in maintaining host immune homeostasis and raise the promising possibility of considering their use in immune therapies

The proteome of extracellular vesicles produced by the human gut bacteria bacteroides thetaiotaomicron in vivo Is influenced by environmental and host-derived factors

Bacterial extracellular vesicles (BEVs) released from both Gram-negative and Gram-positive bacteria provide an effective means of communication and trafficking of cell signaling molecules. In the gastrointestinal tract (GIT) BEVs produced by members of the intestinal microbiota can impact host health by mediating microbe-host cell interactions. A major unresolved question, however, is what factors influence the composition of BEV proteins and whether the host influences protein packaging into BEVs and secretion into the GIT. To address this, we have analyzed the proteome of BEVs produced by the major human gut symbiont Bacteroides thetaiotaomicron both in vitro and in vivo in the murine GIT in order to identify proteins specifically enriched in BEVs produced in vivo. We identified 113 proteins enriched in BEVs produced in vivo, the majority (62/113) of which accumulated in BEVs in the absence of any changes in their expression by the parental cells. Among these selectively enriched proteins, we identified dipeptidyl peptidases and an asparaginase and confirmed their increased activity in BEVs produced in vivo. We also showed that intact BEVs are capable of degrading bile acids via a bile salt hydrolase. Collectively these findings provide additional evidence for the dynamic interplay of host-microbe interactions in the GIT and the existence of an active mechanism to drive and enrich a selected group of proteins for secretion into BEVs in the GIT

Does Judicial Activism in Constitutional Jurisprudence Contradict the Requirements of Democracy and Law-based State?

Darbe pagrindinis dėmesys skiriamas deramų konstitucinių teismų teisėjų elgesio aiškinant rašytinių konstitucijų tekstus standartų polemikai. Šiame kontekste magistro tezės pagrindiniu objektu būtent ir pasirenkamas vienas iš tokių standartų – teisminis aktyvizmas. Siekiama įvertinti ar šis standartas atitinka demokratijos ir teisinės valstybės keliamus reikalavimus konstitucinės jurisprudencijos kontekste. Sekant iš to, suformuojama darbo hipotezė: teisminis aktyvizmas konstitucinėje jurisprudencijoje prieštarauja demokratijos ir teisinės valstybės reikalavimams. Siekiant pagrindinio darbo tikslo, pirmiausia tyrinėjamas platesnis konstitucinės jurisprudencijos problemų ratas. Nagrinėjamos teisminės valstybės apibrėžtumo, demokratijos ir konstitucionalizmo santykio, konstitucijos tekstiškumo, teisės aiškinimo ir teisėkūros takoskyros problemos. Antrame darbo skyriuje atskleidžiama teisminio aktyvizmo apibrėžimo problema. Remiantis mokslinės literatūros analize, tiriama termino genezė ir vartojimo atvejai, formuojama teisminio aktyvizmo samprata. Nustatoma, kad teisminis aktyvizmas – teisėjo vidiniu įsitikinimu pagrįstas pasirinkimas teisinį ginčą išspręsti pozityvios teisėkūros priemonėmis, kai esant tam tikroms bylos faktinėms ir teisinėms aplinkybėms egzistuoja „subjektyvi“ diskrecija. Toliau pereinama prie teisminio aktyvizmo vertinimo. Pristatomos teisminį aktyvizmą neigiančios demokratijos ir teisinės valstybės idėjos, grindžiamos formalistine, iš dalies pozityvia, teisės samprata, bei teisminį aktyvizmą pripažįstanti ir priešininkų idėjas neigianti kritika, grindžiama sociologine teisės samprata. Remiantis prancūzų ir vokiečių filosofų įžvalgomis konstatuojama, kad santykis tarp minėtų demokratijos ir teisinės valstybės idėjų bei jų kritikos yra analogiškas santykiui tarp idealybės ir realybės. Kitais žodžiais tariant, pripažįstama, kad santykis yra simbolinis. Vadovaujantis apibrėžta simbolizacijos funkcija, performuluojamos teisminį aktyvizmą neigiančios idėjos – nustatomas realybę medituojantis ir aproksimuojantis šių idėjų pobūdis. Performuluotų idėjų išdavoje pripažįstamas teisės aiškinimo pirmumas prieš teisminę teisėkūrą. Magistro tezės hipotezė pasitvirtina: teisminis aktyvizmas iš tiesų prieštarauja demokratijos ir teisinės valstybės reikalavimams.“If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary.” As men are not angels, we have democracy as a form of government. As the representatives of democratic government are not angels, we have constitution restricting the power of representative government. In democratic Western countries the control of constitutional constraints and restrictions on government is usually entrusted to judicial branch of government. Lithuania is no exception. On the other hand if people are controlled by a government and a government is restricted by the constitution, the adherence to which is guarded by the court, many people ask the question raised by Roman poet Decimus Iunius Iuvenali: “Who will guard the guardians themselves?” . Philosophical, Political and Legal Sciences have been trying to solve this dilemma since the ancient times. One of the forms of such polemic, acquired in the discourse of constitutional jurisprudence, is adequate and appropriate behaviour standards for judges in constitutional courts interpreting texts of written constitutions. In academic legal literature these discussions on the requirements for proper interpretation of legislation ussually are covered with terms of “judicial activism” and “judicial restrain”. Judicial activism, one of the above standards, is selected as the object of the present Master Thesis. The aim is to assess whether or not this standard meets the requirements of democracy and law-based state in the context of constitutional jurisprudence. As a result the hypothesis of the thesis is formulated as follows: judicial activism in constitutional jurisprudence contradicts the requirements of democracy and law-based state. The analysis starts with an insight that constitutional issues and lexicon are holistic. Thus the first chapter of the thesis primarily analyzes wider problems of constitutional jurisprudence discourse: definition of a law-based state, relation between constitutionalism and democracy, textual certainty of the constitution, difference between legal interpretation and law-making. Following the analysis of these problems, conclusions were made relevant for further assessment of judicial activism; the most important of them are worth to be mentioned here. First, formal and substantial features of the concept of law-based state were identified. It was revealed that the problem of defying a law-based state becomes a problem of defying the law as depending on the concept of law one group of features or another of a law-based state is articulated. Second, it was shown that the antithesis between constitutionalism and democracy is twofold. On the one hand, constitutionalism is faced with the problem of democratic foundation – constitutionalism at least in a procedurally legitimate sense cannot institutionalize itself in a democratic way. On the other hand, constitutionalism removes political issues from the field of democratic decisions, which also includes a catalogue of human rights. It is concluded that the relation between constitutionalism and democracy is not antagonistic – constitutionalism and democracy are only in a constant tension. This tension is expressed as a problem of justification of authority of the constitution and as a competition between positive and negative liberties. Third, it is shown that constitutional law consists of both written and non-written legal norms and that the quantitative relation between them directly depends on the concept of law. Fourth, it is stated that the separation of legal interpretation and law-making is a question of degree, therefore textual criteria is chosen as a point of difference for heuristic purposes. In this way a conclusion is drawn that linguistic, historic and contextual methods as methods of legal interpretation should be associated more with derivation of law from a text and classified as legal interpretation, while dynamic and other creative methods of legal interpretation should be less associated with derivation of law from text and more associated with law-making. The second chapter of the thesis focuses on the definition of judicial activism. After carrying out the semantic analysis and genesis analysis of the term, it is indicated that although this concept has started to be used very recently, a long and wide history of its meaning, sudden popularity and eclectic expansion in the field of usage caused the problem of judicial activism definition. On the basis of literary analysis the problem of definition is solved by removing part of meanings from the field of concept of the term. Then the remaining meanings of judicial activism are processed and the term is defined. Judicial activism is a choice based on judge's inner belief to settle a legal dispute with positive law-making means when a “subjective” discretion exists in certain factual and legal circumstances. In this context “subjective” discretion is defined as the existence of grounded disagreements on a certain legal issue in the society of lawyers. This is how the concept of judicial activism is dissociated from the issue of “objective” discretion, the possibility of existence of discretion of judges in a legal discourse. Judicial activism having been defined, the assessment of the standard of such behavior of judges is performed in the third part of the thesis. It is shown that the assessment of judicial activism depends on the definition of democracy and law-based state, and this in return, as indicated above, depends on the concept of law. In accordance with these regularities, first of all ideas of democracy and law-based state are introduced, based on formalistic, partly positivist concept of law, and denying judicial activism. A chain of the following statements is formed, in accordance with these democratic and law-based state ideas, which does not leave space for judicial law-making: a nation must self-govern itself under the conditions of democratic regime; self-government of a nation is expressed through the will of the people, a political unity of the nation; the will of the nation is transferred to a constitution by creating normative unity of the nation; the written constitution is a clear, consistent, defined, finite system of rules, providing solutions for every factual situation; the court has only to apply these judicial, constitutional rules expressed in a text – the analysis of facts in the case and valuable arguments are not possible. Further the criticism of proponents of judicial activism is provided, on the basis of which the ideas of democracy and law-based state of the opponents of judicial activism are denied. The formalistic concept of law is replaced with realistic/sociological concept of law. Sociology is used to provide a number of criteria that lead to the formulation of statements acknowledging judicial activism: a nation must self-govern itself under the conditions of democratic regime; however, it is often the case that a nation fails to form a common will – there is no political unity; even if the nation forms a common will, then it is often the case that the will is not transferred to the constitution; even when a nation's will is transferred to the constitution, this will cannot be determined by interpreting the text linguistically as there are gaps in the law, and law as a system of rules is obscure, chaotic, undefined and open; the court seeking to implement a democratic requirement of nation's self-government, to find the legal norms common to all, must carry out the analysis of facts in a case and ground the decisions on political, moral and rationalistic values. This does not conclude the assessment of judicial activism. According to the insights of French and German philosophers, it is shown that the relation between the criticism of ideas of judicial activism opponents and mentioned ideas of judicial activism proponents is analogical to the relation between ideality and reality, between a symbolic and existing order. It is claimed that the ideas of democracy and law-based state, based on formalistic concept of law, should be understood as “symbolic orders”. It is admitted that the relations between law and government cannot be the object of knowing in a strict sense, symbology is necessary in order to comprehend them. In this context to symbolize means to mediate and approximate reality by replacing substances with functions. In this way the function of symbology is to define the indefinable, to limit the unlimited. The comprehension of ideas of democracy and law-based state, denying activism, as symbolic order reformulates the statements of judicial activism critics: nation's will, political unity of a nation primarily can be comprehended only through normative unity of a nation; normative unity of a nation primarily can be understood only through positive/textual expression of legislation. The most important thing is that its function is not denied, but at the same time it does not make the reality absolute and only simplifies it to an appropriate level through mediation and approximation. The thesis states that this precedence of the text derives from the common agreement of the people, appearing in the constitutions during the historic Age of Enlightenment, to record the meaning of law in systematized written codes and (a bit later) in constitutions, as people's desire to limit and define the complex reality. On the basis of that conclusion is made that democracy and law-based state as a “symbolic order” prioritize the interpreting of law rather than judicial law-making. Thus hypothesis is confirmed: judicial activism in constitutional jurisprudence contradicts the requirements of democracy and law-based state.Vytauto Didžiojo universiteta