Continuous Culture of Botryococcus braunii for Hydrocarbons Production

Botryococcus braunii is a green, colonial microalga that can produce up to 75% of its dry weight as liquid hydrocarbons that can be converted easily in fuel. In order to cultivate Botryococcus braunii on commercial scale for the biofuel industry, new cultivation methods must be investigated. Until now, no studies have been performed on continuous culture of Botryococcus braunii under a photoperiod (cyclostat mode). The objective of this work is to investigate if the microalga can produce a constant amount of biomass and hydrocarbons in continuous culture under a light/dark cycle. Botryococcus braunii was grown in a stirred tank photobioreactor in continuous culture under a photoperiod of 12 h light and 12 h dark and using warm white LED light and red/blue LED light as light source with intensity of 442 µE m-2 s-1, and compared to continuous and batch culture. Results show that Botryococcus braunii in continuous culture under a photoperiod and in warm white LED light can produce a constant amount of dry biomass and hydrocarbons. Conversely Botryococcus braunii was not able to produce a constant amount of hydrocarbons and dry biomass in red/blue LED light.SHELL TECHNOLOGY CENTRE THORTONSHELL GLOBAL SOLUTION U

A stable genetic polymorphism underpinning microbial syntrophy

Syntrophies are metabolic cooperations, whereby two organisms co-metabolize a substrate in an interdependent manner. Many of the observed natural syntrophic interactions are mandatory in the absence of strong electron acceptors, such that one species in the syntrophy has to assume the role of electron sink for the other. While this presents an ecological setting for syntrophy to be beneficial, the potential genetic drivers of syntrophy remain unknown to date. Here, we show that the syntrophic sulfate-reducing species Desulfovibrio vulgaris displays a stable genetic polymorphism, where only a specific genotype is able to engage in syntrophy with the hydrogenotrophic methanogen Methanococcus maripaludis. This 'syntrophic' genotype is characterized by two genetic alterations, one of which is an in-frame deletion in the gene encoding for the ion-translocating subunit cooK of the membrane-bound COO hydrogenase. We show that this genotype presents a specific physiology, in which reshaping of energy conservation in the lactate oxidation pathway enables it to produce sufficient intermediate hydrogen for sustained M. maripaludis growth and thus, syntrophy. To our knowledge, these findings provide for the first time a genetic basis for syntrophy in nature and bring us closer to the rational engineering of syntrophy in synthetic microbial communities

Untethered: using remote magnetic fields for regenerative medicine

Magnetic fields are increasingly being used for the remote, noncontact manipulation of cells and biomaterials for a wide range of regenerative medical (RM) applications. They have been deployed for their direct effects on biological systems or in conjunction with magnetic materials or magnetically tagged cells for a targeted therapeutic effect. In this work, we highlight the recent trends on the broad use of magnetic fields for the homing of therapeutic cells and particles at targeted tissue sites, biomimetic tissue fabrication, and control of cell fate and proliferation. We also survey the design and control principles of magnetic manipulation systems, including their capabilities and limitations, which can guide future research into developing more effective magnetic field-based regenerative strategies.ISSN:0167-7799ISSN:0167-943

Engineering Inflammation-Resistant Cartilage : Bridging Gene Therapy and Tissue Engineering

Articular cartilage defects caused by traumatic injury rarely heal spontaneously and predispose into post-traumatic osteoarthritis. In the current autologous cell-based treatments the regenerative process is often hampered by the poor regenerative capacity of adult cells and the inflammatory state of the injured joint. The lack of ideal treatment options for cartilage injuries motivated the authors to tissue engineer a cartilage tissue which would be more resistant to inflammation. A clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 knockout of TGF-beta-activated kinase 1 (TAK1) gene in polydactyly chondrocytes provides multivalent protection against the signals that activate the pro-inflammatory and catabolic NF-kappa B pathway. The TAK1-KO chondrocytes encapsulate into a hyaluronan hydrogel deposit copious cartilage extracellular matrix proteins and facilitate integration onto native cartilage, even under proinflammatory conditions. Furthermore, when implanted in vivo, compared to WT fewer pro-inflammatory M1 macrophages invade the cartilage, likely due to the lower levels of cytokines secreted by the TAK1-KO polydactyly chondrocytes. The engineered cartilage thus represents a new paradigm-shift for the creation of more potent and functional tissues for use in regenerative medicine.Peer reviewe

Adaptable test bench for ASTM-compliant permeability measurement of porous scaffolds for tissue engineering

Intrinsic permeability describes the ability of a porous medium to be penetrated by a fluid. Considering porous scaffolds for tissue engineering (TE) applications, this macroscopic variable can strongly influence the transport of oxygen and nutrients, the cell seeding process, and the transmission of fluid forces to the cells, playing a crucial role in determining scaffold efficacy. Thus, accurately measuring the permeability of porous scaffolds could represent an essential step in their optimization process. In literature, several methods have been proposed to characterize scaffold permeability. Most of the currently adopted approaches to assess permeability limit their applicability to specific scaffold structures, hampering protocols standardization, and ultimately leading to incomparable results among different laboratories. The content of novelty of this study is in the proposal of an adaptable test bench and in defining a specific testing protocol, compliant with the ASTM International F2952-22 guidelines, for reliable and repeatable measurements of the intrinsic permeability of TE porous scaffolds. The developed permeability test bench (PTB) exploits the pump-based method, and it is composed of a modular permeability chamber integrated within a closed-loop hydraulic circuit, which includes a peristaltic pump and pressure sensors, recirculating demineralized water. A specific testing protocol was defined for characterizing the pressure drop associated with the scaffold under test, while minimizing the effects of uncertainty sources. To assess the operational capabilities and performance of the proposed test bench, permeability measurements were conducted on PLA scaffolds with regular (PS) and random (RS) micro-architecture and on commercial bovine bone matrix-derived scaffolds (CS) for bone TE. To validate the proposed approach, the scaffolds were as well characterized using an alternative test bench (ATB) based on acoustic measurements, implementing a blind randomized testing procedure. The consistency of the permeability values measured using both the test benches demonstrated the reliability of the proposed approach. A further validation of the PTB's measurement reliability was provided by the agreement between the measured permeability values of the PS scaffolds and the theory-based predicted permeability value. Once validated the proposed PTB, the performed measurements allowed the investigation of the scaffolds' transport properties. Samples with the same structure (guaranteed by the fused-deposition modeling technique) were characterized by similar permeability values, and CS and RS scaffolds showed permeability values in agreement with the values reported in the literature for bovine trabecular bone. In conclusion, the developed PTB and the proposed testing protocol allow the characterization of the intrinsic permeability of porous scaffolds of different types and dimensions under controlled flow regimes, representing a powerful tool in view of providing a reliable and repeatable framework for characterizing and optimizing scaffolds for TE applications

Accounting and the Papal States: The influence of the Pro commissa

The aim of this article is to explore the role played by accounting in the building of the early modern Papal States. In particular, the study shows how the control and accountability system set up by the Pro commissa Bull (15 August 1592) allowed the Pope to concentrate and centralize political power, fostering the shift of the Papal States towards the configuration of an absolute state which can be considered the first major institutional embodiment of the modern state in the early modern period. Besides contributing to the literature on accounting and state building, this research also provides insights into the role of accounting in religious institutions. The analysis, in fact, is carried out in one of the most important religious institutions in history. Moreover, the fact that the Pope was both the political and the religious head of the Papal States allows the inference that this peculiar “dual role” could have affected the setting up of the abovementioned control and accountability system