Serial Transfer Research Articles

Commentary on: The Effects of Fat Harvesting and Preparation, Air Exposure, Obesity, and Stem Cell Enrichment on Adipocyte Viability Prior to Graft Transplantation.

The authors provide a thorough investigation into the variables affecting adipocyte viability ahead of graft transplantation.1 While several reports have examined individual components of techniques used for fat harvest, processing, and injection in relation to adipocyte survival and fat graft retention, there is a lack of systematic and objective evaluation integrating all of these factors in one study. This study is novel in its inclusion of many such variables and it is certainly unique in its integration of them into a single study involving almost fifty patients. The authors evaluated low vs high pressure lipoaspiration, decantation vs centrifugation, high vs low gravitational force centrifugation, serial syringe transfer among dissimilar calibers, ambient air exposure, and use of local anesthetic. Of particular interest is the inclusion of findings illuminating the relative frailty of the hypertrophic adipocytes of obese individuals. Moreover, their findings regarding ASC enrichment corroborate the body of knowledge extoling the benefits of cell assisted lipotransfer in graft retention.2 Similar …

Identification of Beef Heifers with Superior Uterine Capacity for Pregnancy.

Infertility and subfertility represent major problems in domestic animals and humans, and the majority of embryonic loss occurs during the first month of gestation that involves pregnancy recognition and conceptus implantation. The critical genes and physiological pathways in the endometrium that mediate pregnancy establishment and success are not well understood. In study one, predominantly Angus heifers were classified based on fertility using serial embryo transfer to select animals with intrinsic differences in pregnancy loss. In each of the four rounds, a single in vitro-produced, high-quality embryo was transferred into heifers on Day 7 postestrus and pregnancy was determined on Days 28 and 42 by ultrasound and then terminated. Heifers were classified based on pregnancy success as high fertile (HF), subfertile (SF), or infertile (IF). In study two, fertility-classified heifers were resynchronized and bred with semen from a single high-fertility bull. Blood samples were collected every other day from Days 0 to 36 postmating. Pregnancy rate was determined on Day 28 by ultrasound and was higher in HF (70.4%) than in heifers with low fertility (36.8%; SF and IF). Progesterone concentrations in serum during the first 20 days postestrus were not different in nonpregnant heifers and also not different in pregnant heifers among fertility groups. In study three, a single in vivo-produced embryo was transferred into fertility-classified heifers on Day 7 postestrus. The uteri were flushed on Day 14 to recover embryos, and endometrial biopsies were obtained from the ipsilateral uterine horn. Embryo recovery rate and conceptus length and area were not different among the heifer groups. RNA was sequenced from the Day 14 endometrial biopsies of pregnant HF, SF, and IF heifers (n = 5 per group) and analyzed by edgeR-robust analysis. There were 26 differentially expressed genes (DEGs) in the HF compared to SF endometrium, 12 DEGs for SF compared to IF endometrium, and three DEGs between the HF and IF endometrium. Several of the DEG-encoded proteins are involved in immune responses and are expressed in B cells. Results indicate that preimplantation conceptus survival and growth to Day 14 is not compromised in SF and IF heifers. Thus, the observed difference in capacity for pregnancy success in these fertility-classified heifers is manifest between Days 14 and 28 when pregnancy recognition signaling and conceptus elongation and implantation must occur for the establishment of pregnancy.

Efficient production of multi-modified pigs for xenotransplantation by 'combineering', gene stacking and gene editing.

Xenotransplantation from pigs could alleviate the shortage of human tissues and organs for transplantation. Means have been identified to overcome hyperacute rejection and acute vascular rejection mechanisms mounted by the recipient. The challenge is to combine multiple genetic modifications to enable normal animal breeding and meet the demand for transplants. We used two methods to colocate xenoprotective transgenes at one locus, sequential targeted transgene placement - ‘gene stacking’, and cointegration of multiple engineered large vectors - ‘combineering’, to generate pigs carrying modifications considered necessary to inhibit short to mid-term xenograft rejection. Pigs were generated by serial nuclear transfer and analysed at intermediate stages. Human complement inhibitors CD46, CD55 and CD59 were abundantly expressed in all tissues examined, human HO1 and human A20 were widely expressed. ZFN or CRISPR/Cas9 mediated homozygous GGTA1 and CMAH knockout abolished α-Gal and Neu5Gc epitopes. Cells from multi-transgenic piglets showed complete protection against human complement-mediated lysis, even before GGTA1 knockout. Blockade of endothelial activation reduced TNFα-induced E-selectin expression, IFNγ-induced MHC class-II upregulation and TNFα/cycloheximide caspase induction. Microbial analysis found no PERV-C, PCMV or 13 other infectious agents. These animals are a major advance towards clinical porcine xenotransplantation and demonstrate that livestock engineering has come of age.

Development of a plasmid-based expression system in Clostridium thermocellum and its use to screen heterologous expression of bifunctional alcohol dehydrogenases (adhEs)

Clostridium thermocellum is a promising candidate for ethanol production from cellulosic biomass, but requires metabolic engineering to improve ethanol yield. A key gene in the ethanol production pathway is the bifunctional aldehyde and alcohol dehydrogenase, adhE. To explore the effects of overexpressing wild-type, mutant, and exogenous adhEs, we developed a new expression plasmid, pDGO144, that exhibited improved transformation efficiency and better gene expression than its predecessor, pDGO-66. This new expression plasmid will allow for many other metabolic engineering and basic research efforts in C. thermocellum. As proof of concept, we used this plasmid to express 12 different adhE genes (both wild type and mutant) from several organisms. Ethanol production varied between clones immediately after transformation, but tended to converge to a single value after several rounds of serial transfer. The previously described mutant C. thermocellum D494G adhE gave the best ethanol production, which is consistent with previously published results.

Constrained evolvability of interferon suppression in an RNA virus.

Innate immunity responses controlled by interferon (IFN) are believed to constitute a major selective pressure shaping viral evolution. Viruses encode a variety of IFN suppressors, but these are often multifunctional proteins that also play essential roles in other steps of the viral infection cycle, possibly limiting their evolvability. Here, we experimentally evolved a vesicular stomatitis virus (VSV) mutant carrying a defect in the matrix protein (M∆51) that abolishes IFN suppression and that has been previously used in the context of oncolytic virotherapy. Serial transfers of this virus in normal, IFN-secreting cells led to a modest recovery of IFN blocking capacity and to weak increases in viral fitness. Full-genome ultra-deep sequencing and phenotypic analysis of population variants revealed that the anti-IFN function of the matrix protein was not restored, and that the Mdelta51 defect was instead compensated by changes in the viral phosphoprotein. We also show that adaptation to IFN-secreting cells can be driven by the selection of fast-growing viruses with no IFN suppression capacity, and that these population variants can be trans-complemented by other, IFN-suppressing variants. Our results thus suggest that virus-virus interactions and alternative strategies of innate immunity evasion can determine the evolution of IFN suppression in a virus.

Assessment of anti-bacterial activity of silver ions in infected diabetic foot ulcers – An answer to antibiotic resistance

Background: Easy accessibility and irrational use of antibiotics has led to emergence and spread of multidrug bacteria in nosocomial and community settings. MDR strains of Pseudomonas aeruginosa, Staphylococcus aureus and Enterobacteriaceae are commonly isolated from infected diabetic ulcers. Escalating antibiotic resistance has led us to reconsider use of heavy metals particularly silver which is known to reduce bacterial burden in infected wounds. This study aims to assess the bactericidal and clinical effect of silver alginate foam dressings on infected diabetic foot ulcers. Methods & Materials: Fifty cases of infected diabetic foot ulcers were studied. Quantitative bacterial cultures on sheep blood agar were performed as baseline (prior to treatment) and at 7 and 14 days following treatment with silver alginate dressing. Results of quantitative cultures were co-related with clinical improvement in ulcer size and local signs of infection. Bacteria isolated were identified and antibiogram was determined as per CLSI guidelines. Killing curves were recorded by inoculating the surface of silver alginate dressing with 105 bacteria. Sensitivity and duration of silver ion activity was assessed by disc diffusion method on nutrient agar using 7mm disc of silver dressing. Growth inhibition zone diameters were recorded by serial transfer of silver ion foam disc onto freshly inoculated plates for 7 consecutive days. Results: Bacteria isolated included S.aureus 32% (28% MRSA), E.coli 24% (39% ESBL producers, 12% MBL producers), P.aeruginosa 37% (15% MBL producers), Enterobacter spp 4% and Citrobacter 3%. Killing curves showed sterility approximately one to 2.5 hours following exposure to silver ions. All the isolates were sensitive to silver ions irrespective of their antibiotic resistance status. Growth inhibition zone diameters were maintained steady upto 7 days. In all cases decrease in bacterial load was associated with decrease in ulcer size. Conclusion: This study shows topical use of silver ions could serve as an effective alternative to topical or oral antibiotics in management of infected wounds. When used once weekly silver alginate foam dressing appears to be effective in reducing wound bio-burden which is positively associated with ulcer healing. Thus we can conclude that silver ions can be used effectively for treatment of chronic ulcers.

High‐efficient xylitol production by evolved Candida maltosa adapted to corncob hemicellulosic hydrolysate

ABSTRACTBACKGROUNDTo compete with chemical hydrogenation, xylitol production by a biotechnological method has to decrease production cost by improving the performance of the strain, using low‐cost substrate and developing a simple and efficient bioprocess. This study attempted to reach high‐efficient xylitol production using cheap substrate.RESULTSA new evolved strain, Candida maltosa CHH65 showed improved cell growth in corncob hemicellulosic hydrolyzate (CHH) and similar product performance using xylose and CHH as substrate, was developed by serial culture transfer for adapting to CHH and solving the problem of inhibition of CHH. The new strain was recycled at least four times and still produced xylitol. In the test conditions, xylitol concentration reached more than 100 g L−1 within 48 h, with yield > 0.73 g g−1, and productivity > 2 g L−1 h−1 when using CHH as substrate.CONCLUSIONThe capability of the xylose‐fermenting C. maltosa to convert CHH to xylitol was greatly enhanced so that the newly developed bioprocess for xylitol production from low‐cost substrate with multiple recycled C. maltosa could be suitable for industrial application and reduce the production cost. © 2016 Society of Chemical Industry

Adaptive engineering of a hyperthermophilic archaeon on CO and discovering the underlying mechanism by multi-omics analysis.

The hyperthermophilic archaeon Thermococcus onnurineus NA1 can grow and produce H2 on carbon monoxide (CO) and its H2 production rates have been improved through metabolic engineering. In this study, we applied adaptive evolution to enhance H2 productivity. After over 150 serial transfers onto CO medium, cell density, CO consumption rate and H2 production rate increased. The underlying mechanism for those physiological changes could be explained by using multi-omics approaches including genomic, transcriptomic and epigenomic analyses. A putative transcriptional regulator was newly identified to regulate the expression levels of genes related to CO oxidation. Transcriptome analysis revealed significant changes in the transcript levels of genes belonging to the categories of transcription, translation and energy metabolism. Our study presents the first genome-scale methylation pattern of hyperthermophilic archaea. Adaptive evolution led to highly enhanced H2 productivity at high CO flow rates using synthesis gas produced from coal gasification.

Enhancement of D-lactic acid production from a mixed glucose and xylose substrate by the Escherichia coli strain JH15 devoid of the glucose effect.

BackgroundA thermal tolerant stereo-complex poly-lactic acid (SC-PLA) can be made by mixing Poly-D-lactic acid (PDLA) and poly-L-lactic acid (PLLA) at a defined ratio. This environmentally friendly biodegradable polymer could replace traditional recalcitrant petroleum-based plastics. To achieve this goal, however, it is imperative to produce optically pure lactic acid isomers using a cost-effective substrate such as cellulosic biomass. The roadblock of this process is that: 1) xylose derived from cellulosic biomass is un-fermentable by most lactic acid bacteria; 2) the glucose effect results in delayed and incomplete xylose fermentation. An alternative strain devoid of the glucose effect is needed to co-utilize both glucose and xylose for improved D-lactic acid production using a cellulosic biomass substrate.ResultsA previously engineered L-lactic acid Escherichia coli strain, WL204 (ΔfrdBC ΔldhA ΔackA ΔpflB ΔpdhR ::pflBp6-acEF-lpd ΔmgsA ΔadhE, ΔldhA::ldhL), was reengineered for production of D-lactic acid, by replacing the recombinant L-lactate dehydrogenase gene (ldhL) with a D-lactate dehydrogenase gene (ldhA). The glucose effect (catabolite repression) of the resulting strain, JH13, was eliminated by deletion of the ptsG gene which encodes for IIBCglc (a PTS enzyme for glucose transport). The derived strain, JH14, was metabolically evolved through serial transfers in screw-cap tubes containing glucose. The evolved strain, JH15, regained improved anaerobic cell growth using glucose. In fermentations using a mixture of glucose (50 g L−1) and xylose (50 g L−1), JH15 co-utilized both glucose and xylose, achieving an average sugar consumption rate of 1.04 g L−1h−1, a D-lactic acid titer of 83 g L−1, and a productivity of 0.86 g L−1 h−1. This result represents a 46 % improved sugar consumption rate, a 26 % increased D-lactic acid titer, and a 48 % enhanced productivity, compared to that achieved by JH13.ConclusionsThese results demonstrated that JH15 has the potential for fermentative production of D-lactic acid using cellulosic biomass derived substrates, which contain a mixture of C6 and C5 sugars.

Facial rejuvenation: Serial fat graft transfer

Autologous fat transfer is a century-old method for both aesthetic and reconstructive purposes. It is considered by many plastic surgeons the ideal body filler. The only disadvantage is its variable degree of resorption, which ranged from 45% to 80%. Various groups have studied the effects of cryo-preservation for fat storage, the advantage being that fat harvesting need only be performed once, and thereafter fat injections can be performed using stored fat as an outpatient service. This a clinical study carried out to test the aesthetic outcome of serial injection of the cryo-preserved fat cells for both aesthetic and reconstructive purposes. MethodsClinical evaluation was performed under standardized condition for serial lipofilling between October 2003 and May 2012, and 364 autologous fat transfers were performed in 104 patients ranging in age from 18 to 69years (mean age 34years). ResultsThe postoperative clinical results favored the use of serial fat transfer because the aesthetic and structural results were stable up to 90% of the initial volume more than a year after initial transfer. ConclusionOur data suggest that serial transfer of the cryo-preserved fat leads to better cosmetic results on the basis of outpatient service without increasing the financial burden for our patients.

Replacement of the initial steps of ethanol metabolism inSaccharomyces cerevisiaeby ATP-independent acetylating acetaldehyde dehydrogenase

In Saccharomyces cerevisiae ethanol dissimilation is initiated by its oxidation and activation to cytosolic acetyl-CoA. The associated consumption of ATP strongly limits yields of biomass and acetyl-CoA-derived products. Here, we explore the implementation of an ATP-independent pathway for acetyl-CoA synthesis from ethanol that, in theory, enables biomass yield on ethanol that is up to 40% higher. To this end, all native yeast acetaldehyde dehydrogenases (ALDs) were replaced by heterologous acetylating acetaldehyde dehydrogenase (A-ALD). Engineered Ald− strains expressing different A-ALDs did not immediately grow on ethanol, but serial transfer in ethanol-grown batch cultures yielded growth rates of up to 70% of the wild-type value. Mutations in ACS1 were identified in all independently evolved strains and deletion of ACS1 enabled slow growth of non-evolved Ald− A-ALD strains on ethanol. Acquired mutations in A-ALD genes improved affinity—Vmax/Km for acetaldehyde. One of five evolved strains showed a significant 5% increase of its biomass yield in ethanol-limited chemostat cultures. Increased production of acetaldehyde and other by-products was identified as possible cause for lower than theoretically predicted biomass yields. This study proves that the native yeast pathway for conversion of ethanol to acetyl-CoA can be replaced by an engineered pathway with the potential to improve biomass and product yields.

Efficacy of antimicrobial impregnated urinary catheter in thwarting foreign body associated urinary tract infections caused by Pseudomonas aeruginosa

Event Abstract Back to Event Efficacy of antimicrobial impregnated urinary catheter in thwarting foreign body associated urinary tract infections caused by Pseudomonas aeruginosa Hina Saini1, Sanjay Chhibber1 and Kusum Harjai1 1 Panjab University, Microbiology, India Introduction: Catheter associated urinary tract infections (CAUTIs) are rising exponentially around the globe; especially in intensive care units. The formation of biofilm on the surface of an indwelling urinary catheter (UC) marks the onset of CAUTI. Treatment of CAUTI/eradication of biofilm poses an intricate challenge to clinicians and researchers since bacteria within biofilm have increased protection against host immune response and resistance to antimicrobials. Biofilm-associated bacteria on the surface of UC produce quorum sensing (QS) signal molecules which regulate the expression of genes required for biofilm formation. Attenuation of QS, which in turn regulates biofilm production, seems to be a novel approach to curb CAUTI. The present study was thus designed with a preventive strategy to generate a biomaterial by impregnating a silicone UC with combination of azithromycin (AZM) and ciprofloxacin (CIP) and testing its efficacy in-vitro against Pseudomonas aeruginosa. Materials and Methods: Medical grade silicone tubing (0.30mm X 0.64mm) was impregnated with antimicrobials: 3% CIP and 6% AZM. In-vitro efficacy was assessed for control and AZM-CIP impregnated UC against P. aeruginosa standard strain PAO1 using serial plate transfer test (SPTT), in-vitro biofilm colonization, durability test, scanning electron microscopy (SEM) to visualise biofilm and shelf-life test. Results and Discussion: SPTT of AZM-CIP impregnated UC revealed prominent zones of inhibition (> 30mm) against P. aeruginosa PAO1 during testing period of one month and no bacterial growth was observed around or under the UC. These results indicate prolonged antimicrobial activity of these catheters with sustained diffusion of drugs and absence of resistance development since no bacteria was found attached to catheters following continuous exposure to heavy inoculum of P. aeruginosa. AZM-CIP impregnated UC showed complete inhibition of bacterial colonization and biofilm formation after 24h exposure to P. aeruginosa PAO1. These findings suggest anti-adherence activity of catheters. AZM-CIP impregnated UC were tested for durability by dipping in sterile human urine for 4 weeks simulating biological conditions. The results showed significant decline in biofilm formation over 4 weeks suggesting longer durability. These findings were further confirmed by SEM which showed limited bacterial cells within disrupted biofilm on the surface of antimicrobial impregnated UC as compared with fully grown intact biofilm on the surface of control catheters. Additionally, AZM-CIP impregnated UC showed complete inhibition of biofilm formation at quarterly intervals displaying stable real-time shelf life for one year. Conclusion: AZM-CIP impregnated UC demonstrated prolonged duration of antimicrobial and antibiofilm activity. The present study bring out the fact that synergistic combination of currently available antibiotics AZM and CIP may be usefully applied to generate a biomaterial by impregnating these drugs into a UC to prevent bacterial colonization and biofilm formation. Such a catheter would be beneficial in clinical situations, especially in long-term foreign body associated urinary tract infections. This work was funded by University Grants Commission (UGC), New Delhi, India (F1-17.1/2013-14/MANF-2013-14-SIK-CHA-22060/(SA-III/Website). We thank Sophisticated Analytical Instrumentation Facility (SAIF), Panjab University, Chandigarh for their kind support in Scanning Electron Microscopy

Performance evaluation of SD – cards by "system-on-chip" technology

Subject matter. We propose the hardware and software block for performing write or read operation and testing the performance of different SD-cards using the technology of "system-on-chip" in integrated environment by Altera. This task is relevant for the design of high-performance parallel systems on a chip, where the lower limit for writing speed (and/or reading) is critical and significant. Method. The proposed approach is based on three items. First, schemes are used with programmable logic to create a compact hardware and software unit as part of video system on chip. Secondly, reprogrammable structures are applied that support serial and parallel modes of exchange. Thirdly, the increment of data bus width is possible, via the serial transfer and the parallel connection of multiple units simultaneously. Main Results. The analysis of test results of different memory cards has shown that the speed of writing and reading for all cards differs from the declared one by manufacturer, and the error rate of writing (and reading) of data is 30...50% (for reading ~30%). A maximum download speed of memory cards is possible by increasing the number of cascade-connected blocks. The results show that the simplest implementation of this hardware-software unit requires resources of the order of 2000-2500 elementary logic cells. Each cell implements the logical operation "AND-OR with memory", while the resource ЕР3С25F256C8 of the popular chip family Cyclone III consists of 5976 (26%) of these cells with the chip price equal to $5-10 apiece. Practical Relevance. The authors believe that the proposed hardware-software unit can be regarded as the cheapest specialized component in the ECB domestic microelectronics industry to create video information in real time systems.

体細胞連続核移植で作出されたクローンブタでのエピジェネティック解析：Human BeadChipを用いたゲノムワイドDNAメチル化解析の試み

体細胞連続核移植で作出されたクローンブタでのエピジェネティック解析：Human BeadChipを用いたゲノムワイドDNAメチル化解析の試み

Multicongenic fate mapping quantification of dynamics of thymus colonization.

Postnatal T cell development depends on continuous colonization of the thymus by BM-derived T lineage progenitors. Both quantitative parameters and the mechanisms of thymus seeding remain poorly understood. Here, we determined the number of dedicated thymus-seeding progenitor niches (TSPNs) capable of supporting productive T cell development, turnover rates of niche occupancy, and feedback mechanisms. To this end, we established multicongenic fate mapping combined with mathematical modeling to quantitate individual events of thymus colonization. We applied this method to study thymus colonization in CCR7(-/-)CCR9(-/-) (DKO) mice, whose TSPNs are largely unoccupied. We showed that ∼160-200 TSPNs are present in the adult thymus and, on average, 10 of these TSPNs were open for recolonization at steady state. Preconditioning of wild-type mice revealed a similar number of TSPNs, indicating that preconditioning can generate space efficiently for transplanted T cell progenitors. To identify potential cellular feedback loops restricting thymus colonization, we performed serial transfer experiments. These experiments indicated that thymus seeding was directly restricted by the duration of niche occupancy rather than long-range effects, thus challenging current paradigms of thymus colonization.

단일 핀을 이용한 직렬 통신 설계 및 구현에 관한 연구

최근 가전제품, 모바일 장비, 웨어러블 컴퓨터 등의 IoT 분야에서 센서 정보를 주고 받는 직렬 통신 방식이 사용된다. 기존의 SPI와 I2C 직렬 통신 방식은 클럭과 데이터 2개의 핀을 사용하여 비교적 빠른 속도로 데이터를 전송하는 방식이다. 사용되는 사물들이 점차 작아지고, 데이터 전송 정보의 양이 적어지면서 전송 속도보다는 하드웨어의 단순화가 중요한 설계요소가 되는 응용분야가 늘어나고 있다. 본 논문에서는 단일 핀을 사용하여, 데이터를 직렬로 송 수신하는 회로를 설계하고 FPGA로 구현하였다. 제안된 단일 핀 직렬 통신 프로토콜은 적은 양의 데이터를 저속으로 통신하는 IoT 제품에 적합하다. It has been increased that communicate each other things such as consumer electronics, mobile equipments and wearable computer with serial communication protocol. The conventional method of SPI and I2C high speed serial communication is widely used with 2 pin of clock and data pin. It has been more important than the speed of data transfer to simplify the hardware structure because the IoT components is reduced the hardware complexity. In this paper, we describe the protocol and implementation of serial data transfer with only one pin. The proposed protocol is suitable for the mobile products that send and receive the small amount of data with low speed and low power consumption.

Adaptive mutations in sugar metabolism restore growth on glucose in a pyruvate decarboxylase negative yeast strain.

BackgroundA Saccharomyces cerevisiae strain carrying deletions in all three pyruvate decarboxylase (PDC) genes (also called Pdc negative yeast) represents a non-ethanol producing platform strain for the production of pyruvate derived biochemicals. However, it cannot grow on glucose as the sole carbon source, and requires supplementation of C2 compounds to the medium in order to meet the requirement for cytosolic acetyl-CoA for biosynthesis of fatty acids and ergosterol.ResultsIn this study, a Pdc negative strain was adaptively evolved for improved growth in glucose medium via serial transfer, resulting in three independently evolved strains, which were able to grow in minimal medium containing glucose as the sole carbon source at the maximum specific rates of 0.138, 0.148, 0.141 h−1, respectively. Several genetic changes were identified in the evolved Pdc negative strains by genomic DNA sequencing. Among these genetic changes, 4 genes were found to carry point mutations in at least two of the evolved strains: MTH1 encoding a negative regulator of the glucose-sensing signal transduction pathway, HXT2 encoding a hexose transporter, CIT1 encoding a mitochondrial citrate synthase, and RPD3 encoding a histone deacetylase. Reverse engineering of the non-evolved Pdc negative strain through introduction of the MTH181D allele restored its growth on glucose at a maximum specific rate of 0.053 h−1 in minimal medium with 2% glucose, and the CIT1 deletion in the reverse engineered strain further increased the maximum specific growth rate to 0.069 h−1.ConclusionsIn this study, possible evolving mechanisms of Pdc negative strains on glucose were investigated by genome sequencing and reverse engineering. The non-synonymous mutations in MTH1 alleviated the glucose repression by repressing expression of several hexose transporter genes. The non-synonymous mutations in HXT2 and CIT1 may function in the presence of mutated MTH1 alleles and could be related to an altered central carbon metabolism in order to ensure production of cytosolic acetyl-CoA in the Pdc negative strain.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-015-0305-6) contains supplementary material, which is available to authorized users.

A nanoliter microfluidic serial dilution bioreactor.

Bacterial culture is a basic technique in both fundamental and applied microbiology. The excessive reagent consumption and laborious maintenance of bulk bioreactors for microbial culture have prompted the development of miniaturized on-chip bioreactors. With the minimal choice of two compartments (N = 2) and discrete time, periodic dilution steps, we realize a microfluidic bioreactor that mimics macroscopic serial dilution transfer culture. This device supports automated, long-term microbial cultures with a nanoliter-scale working volume and real-time monitoring of microbial populations at single-cell resolution. Because of the high surface-to-volume ratio, the device also operates as an effective biofilm-flow reactor to support cogrowth of planktonic and biofilm populations. We expect that such devices will open opportunities in many fields of microbiology.

Mutation in galP improved fermentation of mixed sugars to succinate using engineered Escherichia coli AS1600a and AM1 mineral salts medium

Escherichia coli KJ122 was engineered to produce succinate from glucose using the wild type GalP for glucose uptake instead of the native phosphotransferase system (ptsI mutation). This strain now ferments 10% xylose poorly. Mutants were selected by serial transfers in AM1 mineral salts medium with 10% xylose. Clones from this population all exhibited a similar improvement, co-fermentation of an equal mixture of xylose and glucose. One of these, AS1600a, produced 84.26±1.37g/L succinate, equivalent to that produced by the parent (KJ122) from 10% glucose (85.46±1.78g/L). AS1600a was sequenced and found to contain a mutation in galactose permease (GalP, G236D). This mutation was shown to be responsible for the improvement in fermentation using KJΔgalP as the host and expression vectors with native galP and with mutant galP∗. Strain AS1600a and KJΔgalP(pLOI5746; galP∗) also co-fermented a mixture of glucose, xylose, arabinose, and galactose in sugarcane bagasse hydrolysate using mineral salts medium.

Homeland/ Hatufim: serial intertextuality and cultural transfer

Remake de la serie israelienne Hatufim, Homeland est un exemple d’intertextualite d’autant plus interessant que les deux series ont ete concues de maniere presque simultanee et que le transfert culturel s’accompagne d’un deplacement generique, de la chronique intimiste au thriller melant action et melodrame. Les deux series se differencient par leur contexte culturel et ideologique, par les choix narratifs et la dynamique dramatique qu’elles mettent en œuvre et par la facon dont elles abordent les identites ethniques, religieuses et genrees, en particulier autour des figures de l’alterite (l’Arabe, le Musulman) et de la place des personnages feminins.