During viral infection, virus-derived cytosolic nucleic acids are recognized by host intracellular specific sensors. The efficacy of this recognition system is crucial for triggering innate host defenses, which then stimulate more specific adaptive immune responses against the virus. Recent studies show that signal transduction pathways activated by sensing proteins are positively or negatively regulated by many modulators to maintain host immune homeostasis. However, viruses have evolved several strategies to counteract/evade host immune reactions. These systems involve viral proteins that interact with host sensor proteins and prevent them from detecting the viral genome or from initiating immune signaling. In this review, we discuss key regulators of cytosolic sensor proteins and viral proteins based on experimental evidence.

Bee venom (BV) from honey bee (Apis Melifera L.) contains at least 18 pharmacologically active components including melittin (MLT), phospholipase A (PLA), and apamin etc. BV is safe for human treatments dose dependently and proven to possess different healing properties including antibacterial and antiparasitidal properties. Nevertheless, antiviral properties of BV have not well investigated. Hence, we identified the potential antiviral properties of BV and its component against a broad panel of viruses. Co-incubation of non-cytotoxic amounts of BV and MLT, the main component of BV, significantly inhibited the replication of enveloped viruses such as Influenza A virus (PR8), Vesicular Stomatitis Virus (VSV), Respiratory Syncytial Virus (RSV), and Herpes Simplex Virus (HSV). Additionally, BV and MLT also inhibited the replication of non-enveloped viruses such as Enterovirus-71 (EV-71) and Coxsackie Virus (H3). Such antiviral properties were mainly explained by virucidal mechanism. Moreover, MLT protected mice which were challenged with lethal doses of pathogenic influenza A H1N1 viruses. Therefore, these results provides the evidence that BV and MLT could be a potential source as a promising antiviral agent, especially to develop as a broad spectrum antiviral agent.

A new microporous TiO 2 -pillared layered titanate has been prepared by hybridizing the exfoliated titanate with the anatase TiO 2 nanosol. The stable colloidal nano-sheet was obtained by intercalating tetrabutylamine into the layered protonic titanate, H x Ti 2-x/4 0 x/4 O 4 ‚H 2 O (x ) 0.67), with a lepidocrocite-like structure. The colloidal suspension of exfoliated titanate sheets was mixed with the monodispersed anatase TiO 2 nanosol solution prepared by the hydrolysis of titanium isopropoxide with acetylacetone. The obtained nanohybrid was heated at 300 °C for 2 h in order to complete the grafting reaction of intercalated anatase TiO 2 nanosol on the interlayer surface of layered titanate. According to the X-ray diffraction analysis and N 2 adsorption-desorption isotherms, it was found that the TiO 2 -pillared layered titanate showed a pillar height of ∼2 nm, a high surface area of ∼460 m 2 /g, and a pore size of ∼0.95 nm, indicating the formation of a microporous pillar structure. Its photocatalytic activity was evaluated by measuring the total volume of H 2 gas evolved during the irradiation of the catalyst suspensions in water. The H 2 gas evolution was found to increase from the layered titanate (cesium and protonic form) to the unsupported TiO 2 (acac-TiO 2 ) and the TiO 2 -pillared layered titanate, because the electron and hole recombination in the pillared system is thought to be effectively suppressed because of electron transfer between guest and host. A marked enhancement in the activity by ca. 40 times was obtained for TiO 2pillared layered titanate compared to pristine compounds such as layered titanate and anatase TiO 2 nanosol when Pt (0.3 wt %) was doped on the surface of the sample.

A novel pillaring procedure has been developed to prepare TiO 2 -pillared layered titanate with large surface area, high thermal stability, and enhanced photocatalytic activity.