CultCube: Experiments in autonomous in-orbit cultivation on-board a 12-Units CubeSat platform.

The feasibility and design of the CultCube 12U CubeSat hosting a small Environmental Control and Life Support Systems (ECLSS) for the autonomous cultivation of a small plant in orbit is described. The satellite is aimed at running experiments in fruit plants growing for applications in crewed vehicles for long-term missions in space. CultCube is mainly composed of a pressurized vessel, constituting the outer shell of the ECLSS, and by various environmental controls (water, nutrients, air composition and pressure, light, etc.) aimed at maintaining a survivable habitat for the fruit plants to grow. The plant health status and growth performances is monitored using hyperspectral cameras installed within the vessel, able to sense leaves' chlorophyll content and temperature, and allowing the estimation of plant volume in all its life cycle phases. The paper study case is addressed to the in-orbit experimental cultivation of a dwarf tomato plant (MicroTom), which was modified for enhancing the anti-oxidants production and for growing in stressful environments. While simulated microgravity tests have been passed by the MicroTom plant, the organism behaviour in a real microgravity environment for a full seed-to-seed cycle needs to be tested. The CultCube 12U CubeSat mission presents no particular requirements on the kind of orbit, whereas its minimum significative duration corresponds to one seed-to-seed cycle for the plant, which is 90 days for the paper study case. In the paper, after an introduction on the importance of an autonomous testbed for plant cultivation, in the perspective of the implementation of bioregenerative systems on-board future manned long-term missions, the satellite design and the MicroTom engineered plant for in-orbit growth are described. In addition to the description of the whole set of subsystems, with focus on the payload and its controllers and instrumentation, the system budgets are presented. Finally, the first tests conducted by the authors are briefly reported.

Advanced Radar Absorbing Ceramic-Based Materials for Multifunctional Applications in Space Environment.

In this review, some results of the experimental activity carried out by the authors on advanced composite materials for space applications are reported. Composites are widely employed in the aerospace industry thanks to their lightweight and advanced thermo-mechanical and electrical properties. A critical issue to tackle using engineered materials for space activities is providing two or more specific functionalities by means of single items/components. In this scenario, carbon-based composites are believed to be ideal candidates for the forthcoming development of aerospace research and space missions, since a widespread variety of multi-functional structures are allowed by employing these materials. The research results described here suggest that hybrid ceramic/polymeric structures could be employed as spacecraft-specific subsystems in order to ensure extreme temperature withstanding and electromagnetic shielding behavior simultaneously. The morphological and thermo-mechanical analysis of carbon/carbon (C/C) three-dimensional (3D) shell prototypes is reported; then, the microwave characterization of multilayered carbon-filled micro-/nano-composite panels is described. Finally, the possibility of combining the C/C bulk with a carbon-reinforced skin in a synergic arrangement is discussed, with the aid of numerical and experimental analyses.

Retinoic acid analogues inhibit human herpesvirus 8 replication.

BACKGROUND: Retinoids have a pronounced antiviral effect against several viruses. In this study we aimed to investigate the effect of retinoids on human herpesvirus 8 (HHV-8). METHODS: A panel of retinoic acid compounds were tested for their antiviral activity against HHV-8 in human umbilical vascular endothelial cells (HUVECs) and in a human epithelial cell line. The presence, transcription and antigen expression of HHV-8 in infected cells - in the presence or absence of retinoic acid compounds - were evaluated by PCR, reverse transcriptase PCR and immunofluorescence assays; HHV-8 viral load was determined by real-time quantitative PCR. Angiogenesis induced by HHV-8 was also assessed using Cultrex basement membrane extract. RESULTS: The compounds tested specifically inhibited viral promoters, during the early and late phases of infection in both cell systems tested, and resulted in up to 100-fold reduction of viral titre and release of progeny virus. The inhibition of viral replication induced by retinoids in endothelial cells, the primary target of HHV-8-driven transformation in Kaposi's Sarcoma, prevented endothelial cells from developing spindle morphology and in vitro tube formation, characteristic changes associated with HHV-8 infection and transformation. CONCLUSIONS: We show that retinoids inhibit HHV-8 replication and identify new retinoid compounds with a strong antiviral effect. Selective retinoids, particularly those with retinoic acid receptor agonist activity, may be good candidates for the development of antiviral drugs.

Molecular interactions between porcine and human gammaherpesviruses: implications for xenografts?

BACKGROUND: Reactivation of latent herpesviruses is an important cause of morbidity and mortality in human transplantation. This issue might be further complicated in the case of xenotransplantation. Zoonotic viruses could reactivate and replicate in the transplanted tissue, and interactions with homologous human viruses could take place. Since the pig is a favoured animal as donor of organs for human transplants, we analysed the possibility of interactions between porcine and human herpesviruses. Porcine lymphotropic herpesvirus 1 (PLHV-1) is a gammaherpesvirus homologous to Epstein-Barr virus (EBV) and to human herpesvirus 8 (HHV-8), is highly prevalent in pigs and is associated to lymphoproliferative disease in immunosuppressed and transplanted miniature swine. METHODS: The main viral transactivators of PLHV-1, ORF50, ORF57, ORFA6/BZLF1(h), were cloned and tested for their transactivating ability on several EBV and HHV-8 promoters using reporter assays. Also the effects of HHV-8 ORF50, ORF57 and ORFK8 and EBV BRLF1/ R-transactivator (Rta) and BZLF1/ Z-transactivator (Zta) on PLHV-1 lytic promoters were analysed. RESULTS: Porcine lymphotropic herpesvirus 1 ORF50 upregulated all HHV-8 promoters and PLHV-1 ORFA6/BZLF1(h) transactivated EBV promoters. Furthermore, transfection of PLHV-1 ORF50 into BC-3 cells, latently infected with HHV-8, resulted in HHV-8 reactivation. Likewise, HHV-8 ORF50 and EBV BRLF1/Rta had a strong transactivating effect on PLHV-1 promoters. Also EBV BZLF1/Zta and HHV-8 ORF57 induced PLHV-1 transactivation, but at lower levels. CONCLUSION: The results suggest that reciprocal molecular interactions between human and porcine herpesviruses might occur in vivo, and support the hypothesis that PLHV-1 might have pathogenic relevance in the course of xenotransplantation.

Human herpesvirus-8 (Kaposi's sarcoma-associated virus) ORF50 increases in vitro cell susceptibility to human immunodeficiency virus type 1 infection.

ORF50, an immediate-early gene of human herpesvirus-8 (HHV-8), encodes a transactivating protein necessary for virus reactivation and lytic replication. ORF50 was reported recently to synergize with human immunodeficiency virus type 1 (HIV-1) tat at a post-transcriptional level. To study the effects of these molecular interactions on HIV replication and biology, cellular clones stably transformed with ORF50 were obtained by transfection of cell lines of different origin. These clones were infected subsequently with HIV. Experiments showed that ORF50 enhances HIV replication in T and B cells (Jurkat and BC-3 cells) and induces susceptibility and transient permissiveness in non-susceptible glial (A172) cells. Upregulation of viral receptors and co-receptors did not account for increased sensitivity to HIV infection and therefore the action of ORF50 might be modulated by the intracellular environment. Interestingly, non-susceptible cells transformed with ORF50 showed transient production of HIV particles that could spread to adjacent cells by direct contact. These findings show that HHV-8 ORF50 has an enhancing effect on HIV replication in vitro and suggest that the two viruses might interact in co-infected patients.