Removal of Toxic Volatile Compounds in Batch Culture Prolongs Stationary Phase and Delays Death of Escherichia coli

The mechanisms controlling entry into and exit from death phase in the bacterial life cycle remain unclear. While bacterial growth studies in batch cultures traditionally focus on the first three phases during incubation, two additional phases, death phase and long-term stationary phase, are less understood. Although there are a number of stressors that arise during long-term batch culture, including nutrient depletion and the accumulation of metabolic toxins such as reactive oxidative species, their roles in cell death are not well-defined. By manipulating environmental conditions of Escherichia coli incubated in long-term batch culture through chemical and mechanical means, we investigated the role of volatile metabolic toxins in modulating the onset of death phase. Here, we demonstrate that with the introduction of substrates with high binding affinities for volatile compounds, toxic byproducts of normal cell metabolism, into the headspace of batch cultures, cells display prolonged stationary phase and delayed entry into death phase. Addition of these substrates allows cultures to maintain a high cell density for hours to days longer than cultures incubated under standard growth conditions. A similar effect is observed when the gaseous headspace in culture flasks is continuously replaced with sterile air, mechanically preventing the accumulation of metabolic byproducts in batch cultures. We establish that toxic compound(s) are produced during exponential phase, demonstrate that buildup of toxic byproducts influence entry into death phase, and present a novel tool for improving high density growth in batch culture that may be used in future research, industrial, or biotechnology applications. IMPORTANCE Bacteria, such as Escherichia coli , are routinely used in the production of biomaterials because of their efficient and sustainable capacity for synthesis of bioproducts. Industrial applications of microbial synthesis typically utilize cells in stationary phase, when cultures have the greatest density of viable cells. By manipulating culture conditions to delay the transition from stationary phase to death phase, we can prolong stationary phase on a scale of hours to days, thereby maintaining the maximum density of cells that would otherwise quickly decline. Characterization of the mechanisms that control entry into death phase for the model organism Escherichia coli not only deepens our understanding of the bacterial life cycle, but also presents an opportunity to enhance current protocols for batch culture growth and explore similar effects in a variety of widely used bacterial strains.

Variasi Konsentrasi Glukosa pada Media Tumbuh dan Lama Fermentasi Dalam Memproduksi Etanol oleh Isolat BM1-CP14

This study was aimed determine the effect of glucose concentration on ethanol producing BM1-CP14 isolate media and to determine to optimum fermentation time to producing ethanol and to determine the growth phase curve of BM1-CP14 isolates. This study uses 4 glucose concentration (8, 12, 16 and 20%) and 3 fermentation time (14, 17 and 20 days). The experimental-explorative research process was carried out in several stages, namely rejuvenation of BM1-CP14 cultures, culture grow, cell isolates adjustment, glucose level on fermentation media measurement, fermentation, and distillation. The glucose concentration which are at the range of 10?18% have an optimum effect in producing ethanol The highest total ethanol was obtained from the glucose concentration of 16% with a fermentation time of 10 days having a difference in total dissolved solids of 8.30 (?% brix) resulting in the highest total ethanol of 38.75 mL. The glucose concentration of 8% resulted in a less than optimal total ethanol, which was 18.00 mL with a difference in total solids of 4.20 (?% brix), while the glucose concentration of 20% has a difference in total dissolved solids of 6.20 (?% brix) and produced a total ethanol of 26.50 mL. The Fermentation time of 14, 17, and 20 days was effected in producing ethanol, namely if the fermentation was longer, the total ethanol produces would be lower. The fermentation time of 14 days resulted in a total ethanol of 37.50 mL with a difference in total dissolved solids of 5.05 (?% brix). In longer fermentation of 17 and 20 days, the total ethanol produced was decreased, produced smaller total ethanol. The growth curve of BM1-CP14 isolates showed the growth isolates of BM1-CP14 with a growth time of 54 hours, starts from the exponential phase for 12 hours, the stationary phase for 18 hours and ends in the death phase. Keywords: Bacteria, BM1-CP14 isolate, ethanol, fermentation time, glucose concentration

Designing a Visual Novel Game in Nusantara Folklore 'The Origin of Lake Toba' using Renpy Visual Novel Engine

<p align="justify">Public knows about the folklore of the archipelago in Indonesia through stories told directly by parents and their families, passed down orally from parents to children and their ancestors to future generations. Likewise, the folklore of the origin of Lake Toba. The folklore of the archipelago seems to be slowly disappearing because it is only passed down orally and is less desirable and does not rule out being forgotten and extinct. This is what makes the writer decide to conduct research on the folklore of the archipelago through the media of games, namely visual novels with the story of the origin of Lake Toba as the object. The researcher wants to make an application in the form of animation with the help of a program that wants to be enjoyed by many people and can also be used as a learning medium.The game application that will be produced will later be made using the Ren'Py Novel Visual Engine application and the research method that the author will use is an extreme programming as a management system with the following stages: Exploration Phase, Planning Phase, Iteration Phase, Production Phase, Maintenance Phase and Final Publication Stage ( Death Phase), with the existing tools can make the application of the story of the origin of Lake Toba well, then for future research to make it in a 3-dimension version</p>

MazEF-rifampicin interaction suggests a mechanism for rifampicin induced inhibition of persisters

Background Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the ability to withstand various stresses including antibiotics. In a clinical setting bacterial persistence often leads to the recalcitrance of various infections increasing the treatment time and cost. Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxin (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEF TA system that furthers the former’s success rate in treating persistent bacteria. Results In the current study we found that the population of bacteria in the death phase of a batch culture consists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin moderately interacts with MazEF complex with 1:1 stoichiometry. Conclusion Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

MazEF-rifampicin interaction suggests a mechanism for rifampicin induced inhibition of persisters

Background: Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the ability to withstand various stresses including antibiotics. In a clinical setting bacterial persistence often leads to the recalcitrance of various infections increasing the treatment time and cost. Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxin (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEF TA system that furthers the former’s success rate in treating persistent bacteria. Results: In the current study we found that the population of bacteria in the death phase of a batch culture consists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin moderately interacts with MazEF complex with 1:1 stoichiometry.Conclusion: Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

Quo vadis Rorschach-teszt? A Rorschach-próba múltja, jelene, krízisei, megújulása és jövője

Célkitűzés: A tanulmány a Rorschach projektív személyiségvizsgáló eljárás történeti nyomvonalán haladva a teszt fejlődésének, kríziseinek és megújulásának fázisait teszi követhetővé.Módszertan: Alapvető forrásmunkák, monográfiák, történeti és szakirodalmi tanulmányokon alapuló gyűjtés adatainak rendezése, történeti és fejlődési korszakokra tagolása.Eredmények: A teszt szakmatörténeti fejlődési útját hat szakaszra tagolva ismertetjük az ötlettől a megvalósulásig: történések Hermann Rorschach haláláig (1. szakasz); a teszt sorsa a Rorschach halála utáni évtizedben (1923-1936) (2. szakasz); a teszt súlypontjának átkerülése az USA-ba (3. szakasz); a második világháborútól a hetvenes évekig terjedő időszak (1941-1970), a teszt fénykora és alkonya (4. szakasz); a teszt újjászületése, a szintézisteremtő John Exner munkássága (5. szakasz), valamint: támadások tüzében és az új R-PAS teszt születése (6. szakasz).Következtetések: A fejlődési út a teszt keletkezésétől kezdve mindmáig konfliktushordozó. A kauzális gondolkodás fegyelme, a tesztológia pszichometrikus követelményei, valamint az életszerű közelítés, a viselkedés átfogó és intuitív értelmezési módja közt feszülő, megújuló ellentéteket tárja fel. A konfliktus kezelésének történeti jellegzetessége a hegeli „megszüntetve megőrzés" (Aufheben), a régibe ágyazódó, megújuló módszertanok születése. Ezt tükrözi a Rorschach-teszt története is.Objective: This study makes the phases of the test's development, crises and renewal traceable by means of the historical trajectory of the Rorschach Projective Personality Examination Procedure.Methodology: An analysis of data collected from essential sources, including monographs as well as historical and literary studies, broken down into the historical periods of the test's development.Results: The historical trajectory of the test is described in six phases: From the idea to its realisation - the events prior to Hermann Rorschach's death (Phase 1); The fate of the test in the decade after Rorschach's death (1923-36) (Phase 2); The shift in focus to the United States (Phase 3); The period from World War II to the 1970s (1941-1970), The golden age and decline of the test (Phase 4); The rebirth of the test and the work of the synthesiser John Exner (Phase 5); and The test under attack and the birth of the new R-PAS test (Phase 6).Conclusions: The test's path of development, from its genesis up to the present day, has been marked by conflict. This reveals the tense and on-going contradictions between the discipline of causal thinking, the psychometric requirements of testing and a realistic, comprehensive and intuitive approach to interpreting behaviour. A historical feature of conflict management in Hegelian terms is 'sublation ' (Aufheben), or the renewal of methodologies that are embedded in the past. This is also reflected in the history of the Rorschach test.

MazEF-rifampicin interaction suggests a mechanism for rifampicin induced inhibition of persisters

Background: Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the ability to withstand various stresses including antibiotics. In a clinical setting bacterial persistence often leads to the recalcitrance of various infections increasing the treatment time and costs. Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxins (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEF TA system that furthers the former’s success rate in treating persistent bacteria. Results: In the current study we found that the population of bacteria in the death phase of a batch culture consists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin moderately interacts with MazEF complex with 1:1 stoichiometry.Conclusion: Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

MazEF-rifampicin Interaction Suggests a Mechanism for Rifampicin Induced Inhibition of Persisters

Background: Persistence is a natural phenomenon whereby a subset of a population of isogenic bacteria either grow slow or become dormant conferring them with the abilityto withstand various stresses including antibiotics.In a clinical setting bacterial persistence often leads to the recalcitrance of various infectionsincreasing the treatment time and costs.Additionally, some studies also indicate that persistence can also pave way for the emergence of resistant strains. In a laboratory setting this persistent phenotype is enriched in nutritionally deprived environments. Consequently, in a batch culture the late stationary phase is enriched with persistent bacteria. The mechanism of persister cell formation and its regulation is not well understood. Toxin-antitoxins (TA) systems have been implicated to be responsible for bacterial persistence and rifampicin is used to treat highly persistent bacterial strains. The current study tries to explore a possible interaction between rifampicin and the MazEFTA system that furthers the former’s success rate in treating persistent bacteria.Results: In the current study we found that the population of bacteria in the death phase of a batch cultureconsists of metabolically inactive live cells resembling persisters, which showed higher membrane depolarization as compared to the log phase bacteria. We also observed an increase in the expression of the MazEF TA modules in this phase. Since rifampicin is commonly used to kill the persisters, we assessed the interaction of rifampicin with MazEF complex. We showed that rifampicin directly interacts with MazEF complex.Conclusion: Our study suggests that the interaction of rifampicin with MazEF complex might play an important role in inhibition of persisters.

Efek Senyawa Timbal Asetat Terhadap Pertumbuhan Dan Kandungan Pigmen Klorofil Mikroalga Dunaliella sp.

Microalgae is one of the marine biota that has an important role in the waters because it acts as a supplier of food in the waters. Microalgae is a biological source that needs to be exploited because it is rich in essential compounds. Dunaliella sp. is one of the many micro algae used as research. Utilization of Dunaliella sp. quite diverse and has been marketed in developed countries because of its very attractive economic value. This study aims to determine the effects of lead acetate compounds on growth and content of chlorophyll pigments microalgae Dunaliella sp. The results obtained in this study are the lead acetate compounds can affect the number of cells in the growth of microalgae and analysis results obtained with a spectrophotometer showed that the extraction concentration of control day 5 (Exponential Phase) was higher than the concentration of 15 ppm and 25 ppm, whereas extraction on day 21 (Death Phase) concentration of 15 ppm was higher than 25 ppm.Keywords : Dunalella sp., Lead Acetate, Pigment chlorophyll RingkasanMikroalga adalah salah satu biota laut yang memiliki peran penting di perairan karena berfungsi sebagai pemasok makanan di perairan. Mikroalga adalah sumber biologis yang perlu dieksploitasi karena kaya akan senyawa esensial. Dunaliella sp. adalah salah satu dari banyak mikroalga yang digunakan sebagai penelitian. Pemanfaatan Dunaliella sp. cukup beragam dan telah dipasarkan di negara maju karena nilai ekonominya yang sangat menarik. Penelitian ini bertujuan untuk mengetahui efek senyawa timbal asetat terhadap pertumbuhan dan kandungan pigmen klorofil Dunaliella sp. Hasil yang diperoleh dalam penelitian ini adalah senyawa timbal asetat dapat mempengaruhi jumlah sel dalam pertumbuhan mikroalga, penurunan jumlah sel mengikuti konsentrasi timbal asetat yang diberikan dan hasil analisis yang diperoleh dengan spektrofotometer menunjukkan bahwa konsentrasi ekstraksi kontrol hari 5 (Fase Eksponensial) lebih tinggi daripada konsentrasi 15 ppm dan 25 ppm, sedangkan ekstraksi hari 21 (Fase Kematian) konsentrasi 15 ppm lebih tinggi dari 25 ppm.Kata kunci : Dunaliella sp., Timbal Asetat, Pigmen Klorofil

“THE JAMU HERBS ILLUSTRATION CARD” KONSERVASI BUDAYA KESEHATAN MASYARAKAT INDONESIA DENGAN MEDIUM ILUSTRASI AUGMENTED REALITY

In the modern era, Jamu (traditional herbal medicine) is one of the illustrious Indonesian heritage, are packaged into sachets and mixed with various chemical compounds. The authors felt the need to conserve the traditional way of making Jamu, by using only natural resources, for the sake of the next generations. The research discusses the implementation of augmented reality technology to differentiate the main ingredients of Jamu, describing the philosophy of Life and Death phase behind them, detailing the way how to compound them and other trivia. Botany illustrations are utilized in the augmented reality, as it is believed to be the effective media to reach the younger audience.