Dengue fever, caused by the dengue virus (DENV), poses a significant global health challenge, particularly in tropical and subtropical regions. Recent increases in indigenous DENV cases in Europe are concerning, reflecting rising incidence linked to climate change and the spread of Aedes albopictus mosquitoes. These vectors thrive under environmental conditions like temperature and humidity, which are increasingly influenced by climate change. Additionally, global travel accelerates the cross-border spread of mosquito-borne diseases. DENV manifests clinically in a spectrum from asymptomatic cases to severe conditions like dengue hemorrhagic fever and dengue shock syndrome, influenced by viral serotype and host factors. In 2024, Brazil experienced a fourfold increase in dengue cases compared to 2023, accompanied by higher mortality. Conventional control measures, such as vector control, community engagement, and vaccination, proved insufficient as climate change exacerbated mosquito proliferation, challenging containment efforts. In this regard, our review analyzes prevention measures and therapeutic protocols during the outbreak while addressing DENV transmission dynamics, clinical presentations, and epidemiological shifts. It also evaluates diagnostic strategies combining clinical assessment with serological and molecular testing, providing information to improve diagnostic and preventive measures. The global expansion of dengue-endemic regions, including outbreaks in Europe, highlights the urgent need for enhanced surveillance, proactive interventions, and international collaboration to mitigate the growing threat of Dengue and other arboviruses like West Nile, Zika, Chikungunya, Oropouche, and Yellow Fever viruses.

Proteases represent common targets in combating infectious diseases, including COVID-19. The 3-chymotrypsin-like protease (3CLpro) is a validated molecular target for COVID-19, and it is key for developing potent and selective inhibitors for inhibiting viral replication of SARS-CoV-2. In this review, we discuss structural relationships and diverse subsites of 3CLpro, shedding light on the pivotal role of dimerization and active site architecture in substrate recognition and catalysis. Our analysis of bioinformatics and other published studies motivated us to investigate a novel catalytic mechanism for the SARS-CoV-2 polyprotein cleavage by 3CLpro, centering on the triad mechanism involving His41-Cys145-Asp187 and its indispensable role in viral replication. Our hypothesis is that Asp187 may participate in modulating the pK_a of the His41, in which catalytic histidine may act as an acid and/or a base in the catalytic mechanism. Recognizing Asp187 as a crucial component in the catalytic process underscores its significance as a fundamental pharmacophoric element in drug design. Next, we provide an overview of both covalent and non-covalent inhibitors, elucidating advancements in drug development observed in preclinical and clinical trials. By highlighting various chemical classes and their pharmacokinetic profiles, our review aims to guide future research directions toward the development of highly selective inhibitors, underscore the significance of 3CLpro as a validated therapeutic target, and propel the progression of drug candidates through preclinical and clinical phases.

Proteases represent common targets in combating infectious diseases including COVID-19. The 3-chymotrypsin-like protease (3CLpro) is a validated molecular target for COVID-19 and it is key for developing potent and selective inhibitors for inhibiting viral replication of SARS-CoV-2. In this review, we discuss structural relationships and diverse subsites of 3CLpro, shedding light on the pivotal role of dimerization and active site architecture in substrate recognition and catalysis. Our analysis of bioinformatics and other published studies unveil a proposal of a novel catalytic mechanism for the SARS-CoV-2 polyprotein cleavage by 3CLpro, centering on the triad mechanism involving His41-Cys145-Asp187 and its indispensable role in viral replication. Recognizing Asp187 as a crucial component in the catalytic process underscores its significance as a fundamental pharmacophoric element in drug design. Next, we provide an overview of both covalent and non-covalent inhibitors, elucidating advancements in drug development observed in preclinical and clinical trials. By highlighting various chemical classes and their pharmacokinetic profiles, our review aims to guide future research directions toward the development of highly selective inhibitors, underscore the significance of 3CLpro as a validated therapeutic target, and propel the progression of drug candidates through preclinical and clinical phases.

Bacterial ion homeostasis is critical for adaptation and survival. In this study, we show that supplementing 2xTY medium with divalent cations (Ca²⁺, Mg²⁺, Mn²⁺, Fe²⁺, Ni²⁺, and Zn²⁺) from 50 to 1,000 μM significantly enhances the growth of Xanthomonas species by reducing generation time, while monovalent ions (Na⁺, K⁺, Li⁺, and Cl^-) had no significant effect. Among them, Ca²⁺ effectively boosted X. citri fitness, increasing the specific growth rate by up to 223%, shortening the cell cycle, and enhancing adhesion to abiotic surfaces up to 8-fold. Calcium also induced a more uniform and smaller cell morphology, suggesting improved cell division and metabolic efficiency. Colony forming unit counts confirmed a higher viability, excluding dead cell accumulation. These effects were conserved in other Xanthomonadaceae members (X. campestris and S. maltophilia) but not in nonrelated species. Based on these findings, we propose an optimized growth medium named 2xTY-Ca (16 g/L tryptone, 10 g/L yeast extract, 5 g/L NaCl, and 1 mM CaCl₂), which significantly improves Xanthomonas spp. growth kinetics in vitro, enhancing X. citri and X. campestris cultivation for laboratory and industrial applications. Though the precise molecular mechanism behind these phenotypes has yet to be determined, we highlight X. citri as a promising organism to understand the role of divalent cations in bacterial physiology.

Cyclic di-GMP (bis-(3′ → 5′) cyclic dimeric guanosine monophosphate) is a ubiquitous bacterial second messenger that regulates a wide range of cellular processes, including biofilm formation, motility, virulence, and environmental adaptation. Its intracellular levels are dynamically controlled by diguanylate cyclases (DGCs), which synthesize c-di-GMP from GTP, and phosphodiesterases (PDEs), which degrade it into linear pGpG or GMP. The functional effects of cytoplasmic c-di-GMP are mediated through diverse effector proteins, including PilZ domain-containing receptors, transcription factors, and riboswitches. In Leptospira interrogans, a major pathogenic species responsible for leptospirosis, the regulatory roles of c-di-GMP remain poorly understood. Here, we performed a comprehensive bioinformatics and structural analysis of all predicted c-di-GMP related proteins in L. interrogans serovar Copenhageni strain Fiocruz L1-130. Our analysis identified 17 proteins containing GGDEF domain, five proteins containing both GGDEF and EAL domains, four proteins containing EAL domain, five proteins containing HD-GYP domain, 12 proteins containing PilZ domain, and one protein containing an MshEN domain. Comparative analysis with well-characterized bacterial homologs suggests that L. interrogans possess a complex c-di-GMP network, likely involved in modulating biofilm formation, host-pathogen interactions, and environmental survival. These findings provide new insights into the c-di-GMP regulatory network and on signal transduction in Leptospira and lay the foundation for future functional studies aimed at understanding its role in physiology, virulence and persistence.