High level extracellular production of recombinant human interferon alpha 2b in glycoengineered Pichia pastoris: culture medium optimization, high cell density cultivation and biological characterization.

AIMS: The present study was aimed at design of experiments (DoE)- and artificial intelligence-based culture medium optimization for high level extracellular production of a novel recombinant human interferon alpha 2b (huIFNα2b) in glycoengineered Pichia pastoris and its characterization. METHODS AND RESULTS: The artificial neural network-genetic algorithm model exhibited improved huIFNα2b production and better predictability compared to response surface methodology. The optimized medium exhibited a fivefold increase in huIFNα2b titre compared to the complex medium. A maximum titre of huIFNα2b (436 mg l-1 ) was achieved using the optimized medium in the bioreactor. Real-time capacitance data from dielectric spectroscopy were utilized to model the growth kinetics with unstructured models. Biological characterization by antiproliferative assay proved that the purified recombinant huIFNα2b was biologically active, exhibiting growth inhibition on breast cancer cell line. CONCLUSIONS: Culture medium optimization resulted in enhanced production of huIFNα2b in glycoengineered P. pastoris at both shake flask and bioreactor level. The purified huIFNα2b was found to be N-glycosylated and biologically active. SIGNIFICANCE AND IMPACT OF THE STUDY: DoE-based medium optimization strategy significantly improved huIFNα2b production. The antiproliferative activity of huIFNα2b substantiates its potential scope for application in cancer therapy.

Immune Modulation Strategies in Gene Therapy: Overcoming Immune Barriers and Enhancing Efficacy.

The immune system presents significant obstacles to gene therapy, which has limited its use in treating many illnesses. New approaches are needed to overcome these problems and improve the effectiveness of gene therapy. This study explores several techniques to immune regulation within gene therapy, a cutting-edge discipline that aims to optimise results by fine-tuning the immune response. We cover new ways to control the immune system and deliver therapeutic genes just where they are needed, including influencing immunological checkpoints, causing immunotolerance, and making smart use of immunomodulatory drugs. In addition, the study provides insight into new developments in the design of less immunogenic gene delivery vectors, which allow for the extension of transgene expression with minimal adverse immune reactions. In order to maximise the efficacy of gene-based therapies, this review analyses these novel approaches and gives a thorough overview of the present state of the art by addressing obstacles and pointing the way toward future developments in immune regulation. Not only does their integration provide new opportunities for the creation of safer and more effective gene treatments, but it also contains the key to overcome current obstacles.

Modulational instability and soliton generation in chiral Bose-Einstein condensates with zero-energy nonlinearity.

By means of analytical and numerical methods, we address the modulational instability (MI) in chiral condensates governed by the Gross-Pitaevskii equation including the current nonlinearity. The analysis shows that this nonlinearity partly suppresses the MI driven by the cubic self-focusing, although the current nonlinearity is not represented in the system's energy (although it modifies the momentum), hence it may be considered as zero-energy nonlinearity. Direct simulations demonstrate generation of trains of stochastically interacting chiral solitons by MI. In the ring-shaped setup, the MI creates a single traveling solitary wave. The sign of the current nonlinearity determines the direction of propagation of the emerging solitons.

An essential role of Ffar2 (Gpr43) in dietary fibre-mediated promotion of healthy composition of gut microbiota and suppression of intestinal carcinogenesis.

Composition of the gut microbiota has profound effects on intestinal carcinogenesis. Diet and host genetics play critical roles in shaping the composition of gut microbiota. Whether diet and host genes interact with each other to bring specific changes in gut microbiota that affect intestinal carcinogenesis is unknown. Ability of dietary fibre to specifically increase beneficial gut microbiota at the expense of pathogenic bacteria in vivo via unknown mechanism is an important process that suppresses intestinal inflammation and carcinogenesis. Free fatty acid receptor 2 (FFAR2 or GPR43) is a receptor for short-chain fatty acids (acetate, propionate and butyrate), metabolites of dietary fibre fermentation by gut microbiota. Here, we show FFAR2 is down modulated in human colon cancers than matched adjacent healthy tissue. Consistent with this, Ffar2(-/-) mice are hypersusceptible to development of intestinal carcinogenesis. Dietary fibre suppressed colon carcinogenesis in an Ffar2-dependent manner. Ffar2 played an essential role in dietary fibre-mediated promotion of beneficial gut microbiota, Bifidobacterium species (spp) and suppression of Helicobacter hepaticus and Prevotellaceae. Moreover, numbers of Bifidobacterium is reduced, whereas those of Prevotellaceae are increased in human colon cancers than matched adjacent normal tissue. Administration of Bifidobacterium mitigated intestinal inflammation and carcinogenesis in Ffar2(-/-) mice. Taken together, these findings suggest that interplay between dietary fibre and Ffar2 play a key role in promoting healthy composition of gut microbiota that stimulates intestinal health.

RCAD/Ufl1, a Ufm1 E3 ligase, is essential for hematopoietic stem cell function and murine hematopoiesis.

The Ufm1 conjugation system is a novel ubiquitin-like modification system, consisting of Ufm1, Uba5 (E1), Ufc1 (E2) and poorly characterized E3 ligase(s). RCAD/Ufl1 (also known as KIAA0776, NLBP and Maxer) was reported to function as a Ufm1 E3 ligase in ufmylation (Ufm1-mediated conjugation) of DDRGK1 and ASC1 proteins. It has also been implicated in estrogen receptor signaling, unfolded protein response (UPR) and neurodegeneration, yet its physiological function remains completely unknown. In this study, we report that RCAD/Ufl1 is essential for embryonic development, hematopoietic stem cell (HSC) survival and erythroid differentiation. Both germ-line and somatic deletion of RCAD/Ufl1 impaired hematopoietic development, resulting in severe anemia, cytopenia and ultimately animal death. Depletion of RCAD/Ufl1 caused elevated endoplasmic reticulum stress and evoked UPR in bone marrow cells. In addition, loss of RCAD/Ufl1 blocked autophagic degradation, increased mitochondrial mass and reactive oxygen species, and led to DNA damage response, p53 activation and enhanced cell death of HSCs. Collectively, our study provides the first genetic evidence for the indispensable role of RCAD/Ufl1 in murine hematopoiesis and development. The finding of RCAD/Ufl1 as a key regulator of cellular stress response sheds a light into the role of a novel protein network including RCAD/Ufl1 and its associated proteins in regulating cellular homeostasis.

Lag times and parameter mismatches in synchronization of unidirectionally coupled chaotic external cavity semiconductor lasers.

We report an analysis of synchronization between two unidirectionally coupled chaotic external cavity master and slave semiconductor lasers with two characteristic delay times, where the delay time in the coupling is different from the delay time in the coupled systems themselves. We demonstrate that parameter mismatches in photon decay rates for the master and slave lasers can explain the experimental observation that the lag time is equal to the coupling delay time.

Inverse anticipating chaos synchronization.

We derive conditions for achieving inverse anticipating synchronization where a driven time-delay chaotic system synchronizes to the inverse future state of the driver. The significance of inverse anticipating chaos in delineating synchronization regimes in time-delay systems is elucidated. The concept is extended to cascaded time-delay systems.

Parameter mismatches and perfect anticipating synchronization in bidirectionally coupled external cavity laser diodes.

We study perfect chaos synchronization between two bidirectionally coupled external cavity semiconductor lasers and demonstrate that mismatches in laser photon decay rates can explain the experimentally observed anticipating time in synchronization.

Demonstration of optical synchronization of chaotic external-cavity laser diodes.

An experimental demonstration of optical synchronization of chaotic external-cavity semiconductor laser diodes is reported for what is believed to be the first time. It is shown that at an optimum coupling strength between the master and the slave lasers high-quality synchronization can be obtained.

Signal masking for chaotic optical communication using external-cavity diode lasers.

Amplitude modulation is used to encode a message into the output of a chaotic laser-diode optical transmitter, and decoding of the message by use of a synchronized chaotic laser-diode receiver is demonstrated experimentally. The chaotic carrier is shown to effectively mask the transmitted message.

Cascaded synchronization of external-cavity laser diodes.

An experimental demonstration of optical synchronization of a chain of chaotic external-cavity laser diodes is reported for what is believed to be the first time. The experiment is performed in the low-frequency-fluctuation regime.

Integrity of semiconductor laser chaotic communications to naïve eavesdroppers.

The integrity of a chaotic encoding technique based on an external-cavity semiconductor laser transmitter-receiver system is experimentally examined. A semiconductor laser placed in the transmission path of the system is used to represent an eavesdropper intercepting a chaotic communication. The eavesdropper is able to obtain a copy of the transmission but is unable to decode the message. A chaotic communication system based on external-cavity semiconductor lasers is seen therefore to be secure against this form of interception.

Mode hopping in external-cavity diode lasers.

Mode hopping in external-cavity AlGaAs diode lasers has been studied experimentally. Its dependence on the amount of feedback and the external-cavity round-trip phase has been studied. The results are compared with the predictions of potential well models. As the feedback is increased the results differ considerably from this theory. A qualitative treatment is also presented.

Critical signal strength for effective decoding in diode laser chaotic optical communications

Synchronized external-cavity diode lasers are used for chaotic optical encryption and decryption. It is shown that effective decoding requires the signal strength to exceed a certain value determined by the precise operating conditions.

Experimental verification of the synchronization condition for chaotic external cavity diode lasers

The synchronization condition obtained numerically by Ahlers, Parlitz, and Lauterborn [Phys. Rev. E 58, 7208 (1998)] is verified experimentally.

Transition between anticipating and lag synchronization in chaotic external-cavity laser diodes.

Chaotic synchronization is investigated by use of two diode lasers as transmitter and receiver. The transmitter laser is rendered chaotic by application of optical feedback in an external-cavity configuration. Changes in the spectrum of the synchronized system are shown to be associated with the transition between anticipating and lag synchronization.

Experimental demonstration of anticipating synchronization in chaotic semiconductor lasers with optical feedback.

We report the first experimental observation of anticipating chaotic synchronization in an optical system using two diode lasers as transmitter and receiver. The transmitter laser is rendered chaotic by application of an optical feedback in an external-cavity configuration. It is found that the anticipation time does not depend on the external-cavity round trip time of the transmitter.

Nullified time-of-flight lead-lag in synchronization of chaotic external-cavity laser diodes.

Synchronization of three chaotic diode lasers is effected in a transmitter-mediator-receiver configuration. The transmitter laser's output is bidirectionally coupled to the mediator laser to achieve anticipating synchronization in their output intensities. The mediator laser's output is unidirectionally coupled to the receiver laser to achieve lag synchronization in their output intensities. This combination of lead and lag synchronization nullifies the time-of-flight lead-lag in synchronization between the transmitter and receiver lasers. This approach provides a means of eliminating time-of-flight delays in the synchronization of remote transmitters and receivers.