Open-water marine food webs prominently feature protist plankton as key participants. Historically categorized as phototrophic phytoplankton and phagotrophic zooplankton, contemporary research reveals that numerous organisms actually integrate both phototrophy and phagotrophy within a single cell; these organisms are recognized as mixoplankton. The mixoplankton model dictates that phytoplankton, exemplified by diatoms, are unable to practice phagotrophy, whereas zooplankton are incapable of phototrophy. This revision transforms marine food webs, extending their structures from regional to global implications. This database, the first comprehensive compilation of marine mixoplankton, gathers information regarding their species identification, body size variation, biological processes, and their trophic interactions within the marine environment. To facilitate the characterization of protist plankton life traits for researchers facing challenges, and to equip modelers with a more complete appreciation of these organisms' complex ecological roles including functional and allometric predator-prey relationships, the Mixoplankton Database (MDB) is designed. Mixoplankton functional types, as assessed by the MDB, present knowledge gaps in understanding their nutrition (derived from nitrate, various prey, and their nutritional condition), as well as in obtaining essential vital rates (like growth and reproduction parameters). The study of growth, photosynthesis, and ingestion, alongside the comparative analysis of factors affecting phototrophy and phagocytosis, provides valuable insight into biological processes. Re-examining and re-classifying protistan phytoplankton and zooplankton in extant plankton databases is now possible, providing a clearer picture of their function within marine ecosystems.

Chronic infections, originating from polymicrobial biofilms, frequently resist effective treatment due to the high tolerance these biofilms exhibit towards antimicrobial agents. Polymicrobial biofilm formation is dependent on the interplay of species interactions. Scriptaid Yet, the foundational contribution of the coexistence of multiple bacterial species in the formation of polymicrobial biofilms remains incompletely understood. We studied how the concurrent presence of Enterococcus faecalis, Escherichia coli O157H7, and Salmonella enteritidis impacted the development of a triple-species biofilm. Our observations indicated that the presence of all three species together bolstered biofilm volume and induced a structural modification within the biofilm, transforming it into a tower-like structure. In the triple-species biofilm's extracellular matrix (ECM), the concentrations of polysaccharides, proteins, and eDNAs were significantly altered, relative to the single-species E. faecalis biofilm. We ultimately examined the transcriptomic profile of *E. faecalis*, observing its response to coexisting with *E. coli* and *S. enteritidis* within the triple-species biofilm. The results highlight *E. faecalis*'s ability to dominate and reconfigure the triple-species biofilm. This was accomplished by improving nutrient flow, boosting amino acid production, increasing central carbon metabolism, influencing the microenvironment with biological strategies, and activating flexible stress response systems. The pilot study's findings, based on a static biofilm model, detail the intricate nature of E. faecalis-harboring triple-species biofilms, thereby providing innovative approaches to comprehend the interspecies interactions and to further the development of clinical treatments for polymicrobial biofilms. The collective characteristics of bacterial biofilms affect many aspects of our daily life in significant ways. Chemical disinfectants, antimicrobial agents, and the host immune response encounter a notable increase in resistance when facing biofilms. Multispecies biofilms, in terms of prevalence, are the leading form of biofilms naturally occurring. Hence, there is a critical need for more research devoted to elucidating the characteristics of multispecies biofilms and the repercussions of their properties on the growth and sustainability of the biofilm community. In a static model, we explore how the simultaneous presence of Enterococcus faecalis, Escherichia coli, and Salmonella enteritidis impacts the formation of a triple-species biofilm. This pilot study, alongside transcriptomic analyses, seeks to explore the potential underlying mechanisms leading to the dominance of E. faecalis in triple-species biofilms. Our research uncovers novel insights into the characteristics of triple-species biofilms, indicating the crucial importance of multispecies biofilm composition when selecting antimicrobial treatments.

The significant public health concern of carbapenem resistance is evident. Infections due to carbapenemase-producing Citrobacter spp., including C. freundii, are experiencing an ascending pattern in their prevalence. In conjunction, a complete global genomic database on carbapenemase-producing species of Citrobacter is readily available. Finding them is difficult. Whole-genome sequencing, using short reads, characterized the molecular epidemiology and international spread of 86 carbapenemase-producing Citrobacter species. The data was gleaned from two surveillance programs, active from 2015 to 2017. KPC-2 (26%), VIM-1 (17%), IMP-4 (14%), and NDM-1 (10%) constituted a significant portion of the carbapenemase occurrences. The most important species discovered in the study were C. freundii and C. portucalensis. Clones of C. freundii, predominantly from Colombia (carrying KPC-2), the United States (featuring KPC-2 and -3), and Italy (with VIM-1), were identified. Among the prevalent *C. freundii* clones, ST98 exhibited blaIMP-8 from Taiwan alongside blaKPC-2 from the United States. In contrast, ST22 exhibited blaKPC-2 from Colombia and blaVIM-1 from Italy. C. portucalensis was primarily composed of two clones, ST493 carrying blaIMP-4, restricted to Australia, and ST545, harboring blaVIM-31, confined to Turkey. In Italy, Poland, and Portugal, the Class I integron (In916) was identified in various sequence types (STs), specifically in association with blaVIM-1. In Taiwan, the In73 strain, carrying the blaIMP-8 gene, circulated among various STs, while in Australia, the In809 strain, carrying the blaIMP-4 gene, circulated between different STs. In the global context, Citrobacter spp. exhibit carbapenemase production as a critical issue. Populations of diverse STs, exhibiting a variety of characteristics and distributed geographically, demand continued observation. Genomic surveillance initiatives must employ methodologies capable of differentiating between Clostridium freundii and Clostridium portucalensis strains. Scriptaid Understanding the importance of Citrobacter species is essential. These issues are gaining recognition as substantial factors in hospital-acquired infections among humans. Carbapenemase-producing strains of Citrobacter spp. pose a formidable threat to global healthcare systems, their resistance to practically every beta-lactam antibiotic rendering them highly resistant to therapy. We articulate the molecular properties of a global set of Citrobacter species, identified as producers of carbapenemases. The prevalence of carbapenemase-producing Citrobacter species in this survey was dominated by Citrobacter freundii and Citrobacter portucalensis. It is noteworthy that the misidentification of C. portucalensis as C. freundii when using Vitek 20/MALDI-TOF MS (matrix-assisted laser desorption/ionization-time of flight mass spectrometry) identification methodologies raises critical questions regarding the reliability of future surveys. Two dominant clones, ST98 (blaIMP-8 from Taiwan and blaKPC-2 from the United States), and ST22 (blaKPC-2 from Colombia and blaVIM-1 from Italy) were identified among the *C. freundii* samples. In the C. portucalensis species, ST493, characterized by blaIMP-4, was predominantly found in Australia, and ST545, characterized by blaVIM-31, was predominantly found in Turkey.

Biocatalysts like cytochrome P450 enzymes hold significant industrial potential owing to their capacity for site-specific C-H oxidation, a variety of catalytic mechanisms, and a wide range of compatible substrates. An in vitro conversion assay identified the 2-hydroxylation activity of CYP154C2, originating from Streptomyces avermitilis MA-4680T, when acting upon androstenedione (ASD). The structure of testosterone (TES)-bound CYP154C2 was determined at 1.42 Å resolution, and this structure was used to engineer eight mutants – including single, double, and triple mutant variants – to enhance the conversion process's efficiency. Scriptaid Significant enhancements in conversion rates were observed for mutants L88F/M191F and M191F/V285L, achieving 89-fold and 74-fold increases for TES, and 465-fold and 195-fold increases for ASD, respectively, when compared to the wild-type (WT) enzyme, while maintaining high 2-position selectivity. In contrast to wild-type CYP154C2, the L88F/M191F mutant exhibited a superior affinity for binding TES and ASD, which was reflected in the increased conversion efficiencies. The L88F/M191F and M191F/V285L mutants showed a significant increase in their total turnover and kcat/Km values. It is noteworthy that every mutant with L88F yielded 16-hydroxylation products, highlighting L88's crucial role in CYP154C2's substrate specificity and suggesting that the equivalent amino acid to L88 in the 154C subfamily affects the positioning of steroid molecules and their substrate selectivity. The medicinal value of hydroxylated steroid derivatives is undeniable. Steroid methyne groups undergo hydroxylation by cytochrome P450 enzymes, a process that significantly modifies their polarity, biological activity, and toxicity. There exists a dearth of research on the 2-hydroxylation of steroids, with the documented 2-hydroxylase P450s showcasing highly reduced conversion rates along with poor regio- and stereoselectivity. The current study, employing crystal structure analysis and structure-guided rational engineering strategies on CYP154C2, effectively boosted the conversion efficiency of TES and ASD, with high levels of regio- and stereoselectivity.