Arginine plays diverse roles in cellular physiology. As a semi-essential amino acid, arginine deprivation has been used to target cancers with arginine synthesis deficiency. Arginine-deprived cancer cells exhibit mitochondrial dysfunction, transcriptional reprogramming and eventual cell death. In this study, we show in prostate cancer cells that arginine acts as an epigenetic regulator to modulate histone acetylation, leading to global upregulation of nuclear-encoded oxidative phosphorylation (OXPHOS) genes. TEAD4 is retained in the nucleus by arginine, enhancing its recruitment to the promoter/enhancer regions of OXPHOS genes and mediating coordinated upregulation in a YAP1-independent but mTOR-dependent manner. Arginine also activates the expression of lysine acetyl-transferases and increases overall levels of acetylated histones and acetyl-CoA, facilitating TEAD4 recruitment. Silencing of TEAD4 suppresses OXPHOS functions and prostate cancer cell growth in vitro and in vivo. Given the strong correlation of TEAD4 expression and prostate carcinogenesis, targeting TEAD4 may be beneficially used to enhance arginine-deprivation therapy and prostate cancer therapy.

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Phenotypic plasticity is the ability of a single genotype of an organism to exhibit variable phenotypes in response to fluctuating environments. It plays a crucial role in their evolutionary success. In natural environments, the importance of interactions between microalgae and other microorganisms is generally well appreciated, but the effects of these interactions on algal phenotypic plasticity has not been investigated. In this study, it revealed that indole-3-acetic acid (IAA), the most common naturally occurring plant hormone, can exert stimulatory at low concentrations and inhibitory effects at high concentrations on the growth of the green alga Desmodesmus. The morphological characteristics of Desmodesmus changed drastically under exposure to IAA compared with the algae in the control environment. The proportion of Desmodesmus unicells in monocultures increased with the IAA concentration, and these unicells exhibited less possibility of sedimentation than large cells. Furthermore, we discovered that lipid droplets accumulated in algal cells grown at a high IAA concentration. Results also demonstrated that the presence of algal competitor further stimulated inducible morphological changes in Desmodesmus populations. The relative abundance of competitors influenced the proportion of induced morphological changes. The results indicate that phenotypic plasticity in microalgae can be a response to fluctuating environments, in which algae optimize the cost–benefit ratio.

host's population and by genetic trade-offs in adaptation to different hosts. Thus, co-evolutionary consequence critically depends on the pervasiveness of genetic interactions. Ophiocordyceps unilateralis (Clavicipitaceae: Hypocreales), also referred to as a "zombie fungus, " is a fungal pathogen considered specific to ants of the tribe Camponotini (Formicinae: Formicidae). This entomopathogen currently found predominantly in tropical forest ecosystems 9. Due to the increased amount of research on Ophiocordyceps in recent years, the name O. unilateralis is often extended to O. unilateralis sensu lato, which suggests that there are several cryptic species within O. unilateralis, which are yet to be described 9. Studies have reported that O. unilateralis in the southern Thailand mainly parasitize carpenter ants, especially Camponotus leonardi, as principal hosts with minor supplementary infections found in some Polyrhachis ants 3,10. Evans et al. 11 found diversity within the complex in four different Camponotus species in Brazil and suggested that O. unilateralis seems to be a species complex of widespread distribution with noticeable local diversities of associated hosts. Subsequent papers dealing with new taxa and issues from Thailand, Japan, and Brazilian Amazon on both Camponotus and Polyrhachis hosts have provided evidence to support for the "one ant, one Ophiocordyceps species" hypothesis as raised by Evans et al. 11-15. Thus, O. unilateralis may have specificity toward different ant species, species delimitation, and host-parasite interaction leading to speciation. We herein report an O. unilateralis s.l. species that can sympatrically infect eight ant species, namely P.