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Abstract The evaluation of white matter lesions (WMLs) showing the central vein sign (CVS) and paramagnetic rim lesions (PRLs) has been suggested to enhance the diagnostic work‐up of adult multiple sclerosis (MS). We aimed to evaluate the fulfillment of different CVS criteria and the added value of PRLs in 22 pediatric MS patients. Eleven patients (50%) fulfilled the 40%‐rule threshold. Nineteen (86%) patients had ≥3 CVS+ WMLs or ≥1 PRL, whereas 17 (77%) had ≥6 CVS+ WMLs or ≥1 PRL. A simplified CVS‐based approach, with the combined evaluation of ≥1 PRL in patients with ≥6 CVS+ WMLs, may improve MS diagnosis in pediatric patients.

Abstract Castration-resistant prostate cancer (CRPC) is a frequently occurring disease with adverse clinical outcomes and limited therapeutic options. Here, we identify methionine adenosyltransferase 2a (MAT2A) as a critical driver of the androgen-indifferent state in ERG fusion-positive CRPC. MAT2A is upregulated in CRPC and cooperates with ERG in promoting cell plasticity, stemness and tumorigenesis. RNA, ATAC and ChIP-sequencing coupled with histone post-translational modification analysis by mass spectrometry show that MAT2A broadly impacts the transcriptional and epigenetic landscape. MAT2A enhances H3K4me2 at multiple genomic sites, promoting the expression of pro-tumorigenic non-canonical AR target genes. Genetic and pharmacological inhibition of MAT2A reverses the transcriptional and epigenetic remodeling in CRPC models and improves the response to AR and EZH2 inhibitors. These data reveal a role of MAT2A in epigenetic reprogramming and provide a proof of concept for testing MAT2A inhibitors in CRPC patients to improve clinical responses and prevent treatment resistance.

Summary: Nutrient digestion, absorption, and export must be coordinated in the gut to meet the nutritional needs of the organism. We used the Drosophila intestine to characterize the mechanisms that coordinate the fate of dietary lipids. We identified enterocytes specialized in absorbing and exporting lipids to peripheral organs. Distinct hepatocyte-like cells, called oenocytes, communicate with these enterocytes to adjust intestinal lipid storage and export. A single transcription factor, Drosophila hepatocyte nuclear factor 4 (dHNF4), supports this gut-liver axis. In enterocytes, dHNF4 maximizes dietary lipid export by preventing their sequestration in cytoplasmic lipid droplets. In oenocytes, dHNF4 promotes the expression of the insulin antagonist ImpL2 to activate Foxo and suppress lipid retention in enterocytes. Disruption of this switch between lipid storage and export is associated with intestinal inflammation, suggesting a lipidic origin for inflammatory bowel diseases. These studies establish dHNF4 as a central regulator of intestinal metabolism and inter-organ lipid trafficking.

Abstract Hepatic impairment (HI) moderately (10‐fold) for drugs that are also substrates of cytochrome P450 (CYP) 3A enzymes. Using the extended clearance model, through simulations, we identified the ratio of sinusoidal efflux clearance (CL) over the sum of metabolic and biliary CLs as important in predicting the impact of HI on the AUC of dual OATP/CYP3A substrates. Because HI may reduce hepatic CYP3A‐mediated CL to a greater extent than biliary efflux CL, the greater the contribution of the former versus the latter, the greater the impact of HI on drug AUC ratio (AUCRHI). Using physiologically‐based pharmacokinetic modeling and simulation, we predicted relatively well the AUCRHI of OATP substrates that are not significantly metabolized (pitavastatin, rosuvastatin, valsartan, and gadoxetic acid). However, there was a trend toward underprediction of the AUCRHI of the dual OATP/CYP3A4 substrates fimasartan and atorvastatin. These predictions improved when the sinusoidal efflux CL of these two drugs was increased in healthy volunteers (i.e., before incorporating the effect of HI), and by modifying the directionality of its modulation by HI (i.e., increase or decrease). To accurately predict the effect of HI on AUC of hepatobiliary cleared drugs it is important to accurately predict all hepatobiliary pathways, including sinusoidal efflux CL.

Following preliminary underwater observations of about 1000 h carried out monthly between 2012 and 2023 (except the years 2021 and 2022), 23 specimens of grey reef sharks were spotted and photo-identified off the coast of Nosy Be in Madagascar, on an emerging reef called “Mokarran” at a depth between 15 and 30 m. Over 10 years of observations, eight specimens were re-sighted, identified with a non-invasive photo-identification technique of part of the first dorsal and the caudal fin, and one specimen was re-identified after 1982 days from the first sighting, i.e., after more than 5 years. In addition, six specimens of probably pregnant females were also identified in the same area. The population was entirely made up of females. The aggregation area could represent a new nursery site which, if confirmed after further investigations, will require greater protection.

Although there is a clear relationship between family history (FH) and the risk of gastric cancer (GC), quantification is still needed in relation to different histological types and anatomical sites, and in strata of covariates. The objective was to analyze the risk of GC according to first-degree FH in a uniquely large epidemiological consortium of GC. This investigation includes 5946 cases and 12,776 controls from 17 studies of the Stomach Cancer Pooling (StoP) Project consortium. Summary odds ratios (OR) and the corresponding 95% confidence intervals (CIs) were calculated by pooling study-specific ORs using fixed-effect model meta-analysis techniques. Stratified analyses were carried out by sex, age, tumor location and histological type, smoking habit, socioeconomic status, alcohol intake and fruit consumption. The pooled OR for GC was 1.84 (95% CI: 1.64-2.04; I2 = 6.1%, P heterogeneity = 0.383) in subjects with vs. those without first-degree relatives with GC. No significant differences were observed among subgroups of sex, age, geographic area or study period. Associations tended to be stronger for non-cardia (OR = 1.82; 95% CI: 1.59-2.05 for subjects with FH) than for cardia GC (OR = 1.38; 95% CI: 0.98-1.77), and for the intestinal (OR = 1.92; 95% CI: 1.62-2.23) than for the diffuse histotype (OR = 1.62; 95% CI: 1.28-1.96). This analysis confirms the effect of FH on the risk of GC, reporting an approximately doubled risk, and provides further quantification of the risk of GC according to the subsite and histotype. Considering these findings, accounting for the presence of FH to carry out correct prevention and diagnosis measures is of the utmost importance.

IntroductionBioconvection, a phenomenon characterized by the collective upward swimming of motile microorganisms, has mainly been investigated within controlled laboratory settings, leaving a knowledge gap regarding its ecological implications in natural aquatic environments. This study aims to address this question by investigating the influence of bioconvection on the eco-physiology of the anoxygenic phototrophic sulfur bacteria community of meromictic Lake Cadagno.MethodsHere we comprehensively explore its effects by comparing the physicochemical profiles of the water column and the physiological traits of the main populations of the bacterial layer (BL). The search for eco-physiological effects of bioconvection involved a comparative analysis between two time points during the warm season, one featuring bioconvection (July) and the other without it (September).ResultsA prominent distinction in the physicochemical profiles of the water column centers on light availability, which is significantly higher in July. This minimum threshold of light intensity is essential for sustaining the physiological CO2 fixation activity of Chromatium okenii, the microorganism responsible for bioconvection. Furthermore, the turbulence generated by bioconvection redistributes sulfides to the upper region of the BL and displaces other microorganisms from their optimal ecological niches.ConclusionThe findings underscore the influence of bioconvection on the physiology of C. okenii and demonstrate its functional role in improving its metabolic advantage over coexisting phototrophic sulfur bacteria. However, additional research is necessary to confirm these results and to unravel the multiscale processes activated by C. okenii’s motility mechanisms.

Phenolic compounds may exert a favorable effect on the risk of several cancer types, including gastric cancer (GC). However, selected polyphenol classes have not been adequately investigated in relation to GC. The aim of this study is to evaluate the association between the intake of polyphenols in relation to GC risk. We used data from the Stomach cancer Pooling (StoP) Project, including 10 studies from six countries (3471 GC cases and 8344 controls). We carried out an individual participant data pooled analysis using a two-stage approach. The summary odds ratios (ORs) of GC for each compound, and the corresponding 95% confidence intervals (95% CI), were computed by pooling study specific ORs obtained through multivariate logistic regression, using random effect models. Inverse associations with GC emerged for total polyphenols (OR = 0.67, 95% CI = 0.54-0.81, for the highest versus lowest quartile of intake), total flavonoids (OR = 0.73, 95% CI = 0.55-0.90), anthocyanidins (OR = 0.74, 95% CI = 0.56-0.92), flavanols (OR = 0.77, 95% CI = 0.66-0.88), flavanones (OR = 0.57, 95%CI = 0.44-0.69), total phenolic acids (OR = 0.75, 95%CI = 0.55-0.94), and hydroxybenzoic acids (OR = 0.73, 95%CI = 0.57-0.89). Results were consistent across strata of age, sex, social class, and smoking habit. Suggestive inverse associations were also found for flavonols (OR = 0.76, 95%CI = 0.51-1.01) and hydroxycinnamic acids (OR = 0.82, 95%CI = 0.58-1.06). Further investigations from longitudinal data are needed to confirm this association.

Abstract Physiologically based pharmacokinetic models, populated with drug‐metabolizing enzyme and transporter (DMET) abundance, can be used to predict the impact of hepatic impairment (HI) on the pharmacokinetics (PK) of drugs. To increase confidence in the predictive power of such models, they must be validated by comparing the predicted and observed PK of drugs in HI obtained by phenotyping (or probe drug) studies. Therefore, we first predicted the effect of all stages of HI (mild to severe) on the PK of drugs primarily metabolized by cytochrome P450 (CYP) 3A enzymes using the default HI module of Simcyp Version 21, populated with hepatic and intestinal CYP3A abundance data. Then, we validated the predictions using CYP3A probe drug phenotyping studies conducted in HI. Seven CYP3A substrates, metabolized primarily via CYP3A (fraction metabolized, 0.7–0.95), with low to high hepatic availability, were studied. For all stages of HI, the predicted PK parameters of drugs were within twofold of the observed data. This successful validation increases confidence in using the DMET abundance data in HI to predict the changes in the PK of drugs cleared by DMET for which phenotyping studies in HI are not available or cannot be conducted. In addition, using CYP3A drugs as an example, through simulations, we identified the salient PK factors that drive the major changes in exposure (area under the plasma concentration–time profile curve) to drugs in HI. This theoretical framework can be applied to any drug and DMET to quickly determine the likely magnitude of change in drug PK due to HI.

Aim: This case report aims to illustrate a clinical protocol that allows for the rehabilitation of patients requiring extensive osteotomy, simultaneous implant placement, and full-arch, screwed-in prosthetics in one session. This protocol allows for the improvement of the aesthetics and functionality of the fixed implant-supported prosthesis through the preoperative planning of all surgical procedures, including osteotomy, and of the prosthesis through the application of 3D-printing technology for the creation of surgical templates and prostheses. Methods: This case report concerns a 72-year-old patient, ASA1, who, following diagnosis, the establishment of a treatment plan, and the provision of informed consent, opted for an immediate, full-arch rehabilitation of the lower arch. The digital planning stage started with the correct positioning of the fixtures. The proper bone levels were found and used to guide the creation of the provisional screwed-in prothesis. Two templates with the same supports (landmarks/pins) were then 3D-printed: a positioning template, including a slit to assist the surgeon during the osteotomy, and a surgery template to assist the surgeon during the implants’ positioning. A screwed-in prosthesis encased in resin C&B MFH (NEXTDENT®, Soesterberg, The Netherlands) was delivered. Minimal occlusal adjustments were performed. Results: In a single clinical session, through careful planning and the pre-operative 3D printing of a prosthesis, a temporary implant-supported prosthetic rehabilitation was possible in a case that required an extended osteotomy. Clinically, the correspondence between the virtual design phase and the final realization was consistent. At a functional level, the provisional prosthesis required minimal occlusal adjustments and the DVO values obtained in the immediate post-operative period were found to be comparable to those of the virtual design. By planning the final position of the bone and the implants in advance, it was possible to deliver a full-arch prothesis with proper implant emergence, occlusal vertical dimensions, and occlusal relationship. Conclusion: This fully digital protocol allows the clinician to preview and plan the osteotomy and implant surgery as well as the delivery of the temporary, immediately loaded, complete, fixed prosthesis in patients who are candidates for post-extraction surgery with the need for severe osteotomy.

Purpose: Determine the time-dependent magnitude of intrafraction prostate displacement and a cutoff for the tracking decision. Methods: Nine patients with localized prostate cancer were treated with ultra-hypofractionated radiotherapy (CyberKnife) with fiducial markers. Exact tract kV/kV imaging was used with an average interval of 19–92 s. A Gaussian distribution was calculated for the x-, y-, and z-directions (σx,y,z). The variation of prostate motion (μσ) was obtained by averaging the patients’ specifics, and the safety margin was calculated to be MAB = WYm + WBSs. Results: The calculated PTV safety margins were as follows: at 40 s: 0.55 mm (L/r), 0.85 mm (a/p), and 1.05 mm (s/i); at 60 s: 0.9 mm (L/r), 1.35 mm (a/p), and 1.55 mm (s/i); at 100 s: 1.5 mm (L/r), 2.3 mm (a/p), and 2.6 mm (s/i); at 150 s: 1.9 mm (L/r), 3.1 mm (a/p), and 3.6 mm (s/i); at 200 s: 2.2 mm (L/r), 3.8 mm (a/p), and 4.2 mm (s/i); and at 300 s: 2.6 mm (L/r), 5.3 mm (a/p), and 5.6 mm (s/i). A tracking cutoff of 2.5 min seemed reasonable. In order to achieve an accuracy of < 1 mm, tracking with < 50 s intervals was necessary. Conclusions: For ultra-hypofractionated radiotherapy of the prostate with treatment times > 2.5 min, intrafraction motion management is recommended.

Aim: The conometric concept was proposed as a possible connection between the abutment and the prosthetic coping. This research aimed to review the features and possible clinical uses of this connection in an implant-supported fixed prosthesis. Methods: An electronic search was conducted on an online database for the topic in object; articles published in international literature were considered and the research gave 17 results, and 6 parameters were analyzed. Results: This connection eliminated the possibility of cement residues in the subgingival region, reducing the risk of inflammation of peri-implant soft and hard tissues; not having to remove the cement residues, it is possible to place the margins in more apical portions, improving the aesthetics outcomes of the rehabilitations. It is also known that the retention by means of a screw causes a weakening of the restoration. The retentive force is adequate for fixed rehabilitation even after a high number of insertion–disengagement cycles; in vitro studies have also shown a high bacterial sealing. Implant rehabilitation using preformed components, such as conometric hoods, is helpful for CAD/CAM, so a digital workflow is possible. Several types of prosthesis were presented, all of which demonstrated adequate clinical performance in the follow-up observation. Conclusions: This type of connection seems to be suitable to support fixed implant rehabilitations, but long-term clinical studies are needed to validate this system.

Background/Objective: The relationship between food consumption and environmental sustainability is becoming increasingly evident. The aim of this study was to estimate the evolution of the environmental impact of food consumption in the Spanish population, assessed in terms of greenhouse gas (GHG) emissions. Methods: Data collected from the Household Budget Survey were included, from approximately 24,000 households for the period of 2006–2023. The environmental impact of diet, in terms of GHG emissions, was estimated from the EAT-Lancet Commission tables, and the adherence to the Mediterranean Diet (MedDiet) was calculated using the Dietary Score index. Results: The environmental impact of the Spanish diet, in terms of GHG, followed a downward trend over the years analysed, from 3978.1 g CO2-eq in 2006 to 3281.4 g CO2-eq in 2023, a decrease of 17.5%. The food groups with the largest decrease in consumption during this period were red meat (from 39.9 kg/year to 35.5 kg/year), fish (from 24.3 kg/year to 19.0 kg/year), and dairy products (from 113.4 kg/year to 99.7 kg/year). The level of adherence to the MedDiet increased slightly from 34 points in 2006 to 35 points in 2023 due to an increase in the amount of vegetables (42.7 kg/year vs. 44.3 kg/year) and grains consumed (53.1 kg/year vs. 72.6 kg/year) and a decrease in fish consumption (24.3 kg/year vs. 19.0 kg/year). Conclusions: In Spain, a reduction in GHG emissions associated with food consumption was observed due to a decrease in the consumption of red meat, fish, dairy products, and fats. National surveys are very useful tools to analyse the impact of food consumption on climate change and to assess the effect of the policies implemented to contain it. [ABSTRACT FROM AUTHOR]

(1) Background: Urate levels lower than the classical cut-off point for defining hyperuricemia can increase cardiovascular risks. The aim of this study is to determine if there is a relationship between different urate levels and classic cardiovascular risk factors (CVRFs). (2) Methods: A cross-sectional study of the inclusion visits of the patients recruited to the IBERICAN study was conducted. The patients were classified into quartiles according to their distribution of urate levels and separated by sex; the three lower points corresponded to normal levels of urate, and the highest quartile was determined according to the classical definition of HU. Multivariate analysis models, adjusted for epidemiological variables, were used to analyze the association of urate levels with CVRFs. (3) Results: The presence of CVRFs was higher across the quartiles of urate, with a continuous increase along the quartiles in both sexes in accordance with body mass index (p < 0.01), waist circumference (p < 0.01), blood pressure (p < 0.01), and LDL cholesterol (p < 0.01). The CV risk estimated by SCORE was associated with an increase along the quartiles in women (p = 0.02). (4) Conclusions: A progressive increase in the frequency of CVRFs, as well as in their levels, was observed across the quartiles of uricemia, which reflects an increase in the CVRs associated with uricemia. [ABSTRACT FROM AUTHOR]

The evaluation of white matter lesions (WMLs) showing the central vein sign (CVS) and paramagnetic rim lesions (PRLs) has been suggested to enhance the diagnostic work‐up of adult multiple sclerosis (MS). We aimed to evaluate the fulfillment of different CVS criteria and the added value of PRLs in 22 pediatric MS patients. Eleven patients (50%) fulfilled the 40%‐rule threshold. Nineteen (86%) patients had ≥3 CVS+ WMLs or ≥1 PRL, whereas 17 (77%) had ≥6 CVS+ WMLs or ≥1 PRL. A simplified CVS‐based approach, with the combined evaluation of ≥1 PRL in patients with ≥6 CVS+ WMLs, may improve MS diagnosis in pediatric patients. [ABSTRACT FROM AUTHOR]

Research misconduct (RM) is an alarming concern worldwide, and especially in Italy, where there is no formal training of young researchers in responsible research practices. The main aim of this study was to map the perceptions and attitudes about RM in a sample of young researchers attending a one-week intensive course on methodology, ethics and integrity in biomedical research, held at the University of Insubria (Italy). To this end, we administered the Scientific Misconduct Questionnaire (SMQ-R) to all attendees at the beginning of the course. Thereafter, SMQ-R was re-administered at the end, to assess the impact of the course on the responsiveness of study participants, which is intended as the frequency of responses other than "don't know". Results show that respondents rate as high their own understanding about rules and procedures related to scientific misconduct (49.2% of respondents), as well as the effectiveness of their institution's measures for reducing it (40%). Most of them (44.6%) perceive as low the chances of getting caught for RM. Some respondents believe that cases of misconduct occur in their workplace (20%-46.2%) and that the integrity of a research is not solely the responsibility of the principal investigator (73.8%). Among the main factors contributing to research misconduct, the need for publications, unclear definition of what constitutes misconduct and pressure for external funding do stand out. Respondents are concerned about the amount of misconduct and express a pressing need for training on research ethics. Remarkably, the responsiveness of participants tends to increase with course attendance. This finding may be useful to support education programmes devoted to research methodology, ethics and integrity among young researchers.

Following the contraindication of codeine use in children, increasing use of tramadol has been observed in pain management protocols. However, tramadol’s pharmacokinetics (PK) and pharmacodynamics are influenced by cytochrome P450 (CYP)2D6 activity, similarly to codeine. Previous studies in adults have demonstrated a correlation between pupillary response and tramadol PK. Our objective was to evaluate pupillometry as a phenotyping method to assess CYP2D6 activity in children treated with tramadol. We included 41 children (mean age 11 years) receiving a first dose of tramadol (2 mg/kg) in the emergency room (ER) as part of their routine care. CYP2D6 phenotyping and genotyping were performed. The concentrations of tramadol and its active metabolite, M1, were measured, and static and dynamic pupillometry was conducted using a handheld pupillometer at the time of tramadol administration and during the ER stay. Pupillometric measurements were obtained for 37 children. Tramadol affected pupillary parameters, with a decrease in pupil diameter in 83.8% of children (p = 0.002) (mean decrease 14.1 ± 16.7%) and a decrease in reflex amplitude constriction in 78.4% (p = 0.011) (mean decrease 17.7 ± 34.5%) at T150 compared to T0. We were unable to identify a correlation between pupillometry measurements and CYP2D6 activity. Likely confounding factors include light intensity, pain, and stress, making the procedure less feasible in paediatric emergency settings.

N2 fixation was key to the expansion of life on Earth, but which organisms fixed N2 and if Mo-nitrogenase was functional in the low Mo early ocean is unknown. Here, the authors show that purple sulfur bacteria fix N2 using Mo-nitrogenase in a Proterozoic ocean analogue, despite low Mo conditions.

Background Dietary polyphenol intake has been associated with a decreased risk of hyperuricemia, but most of this knowledge comes from preclinical studies. The aim of the present study was to assess the association of the intake of different classes of polyphenols with serum uric acid and hyperuricemia. Methods and Results This cross‐sectional analysis involved baseline data of 6332 participants. Food polyphenol content was estimated by a validated semiquantitative food frequency questionnaire and from the Phenol‐Explorer database. Multivariable‐adjusted linear regression models with serum uric acid (milligrams per deciliter) as the outcome and polyphenol intake (quintiles) as the main independent variable were fitted. Cox regression models with constant follow‐up time (t=1) were performed to estimate the prevalence ratios (PRs) of hyperuricemia (≥7 mg/dL in men and ≥6 mg/dL in women). An inverse association between the intake of the phenolic acid class (β coefficient, −0.17 mg/dL for quintile 5 versus quintile 1 [95% CI, −0.27 to −0.06]) and hydroxycinnamic acids (β coefficient, −0.19 [95% CI, −0.3 to −0.09]), alkylmethoxyphenols (β coefficient, −0.2 [95% CI, −0.31 to −0.1]), and methoxyphenols (β coefficient, −0.24 [95% CI, −0.34 to −0.13]) subclasses with serum uric acid levels and hyperuricemia (PR, 0.82 [95% CI, 0.71–0.95]; PR, 0.82 [95% CI, 0.71–0.95]; PR, 0.80 [95% CI, 0.70–0.92]; and PR, 0.79 [95% CI, 0.69–0.91]; respectively) was found. The intake of hydroxybenzoic acids was directly and significantly associated with mean serum uric acid levels (β coefficient, 0.14 for quintile 5 versus quintile 1 [95% CI, 0.02–0.26]) but not with hyperuricemia. Conclusions In individuals with metabolic syndrome, a higher intake of some polyphenol subclasses (hydroxycinnamic acids, alkylmethoxyphenol, and methoxyphenol) was inversely associated with serum uric acid levels and hyperuricemia. Nevertheless, our findings warrant further research.

ABSTRACT Lake Cadagno, a permanently stratified high-alpine lake with a persistent microbial bloom in its chemocline, has long been considered a model for the low-oxygen, high-sulfide Proterozoic ocean. Although the lake has been studied for over 25 years, the absence of concerted study of the bacteria, phytoplankton, and viruses, together with primary and secondary production, has hindered a comprehensive understanding of its microbial food web. Here, the identities, abundances, and productivity of microbes were evaluated in the context of Lake Cadagno biogeochemistry. Photosynthetic pigments together with 16S rRNA gene phylogenies suggest the prominence of eukaryotic phytoplankton chloroplasts, primarily chlorophytes. Chloroplasts closely related to those of high-alpine-adapted Ankyra judayi persisted with oxygen in the mixolimnion, where photosynthetic efficiency was high, while chloroplasts of Closteriopsis-related chlorophytes peaked in the chemocline and monimolimnion. The anoxygenic phototrophic sulfur bacterium Chromatium dominated the chemocline along with Lentimicrobium, a genus of known fermenters. Secondary production peaked in the chemocline, which suggested that anoxygenic primary producers depended on heterotrophic nutrient remineralization. The virus-to-microbe ratio peaked with phytoplankton abundances in the mixolimnion and were at a minimum where Chromatium abundance was highest, trends that suggest that viruses may play a role in the modulation of primary production. Through the combined analysis of bacterial, eukaryotic, viral, and biogeochemical spatial dynamics, we provide a comprehensive synthesis of the Lake Cadagno microbial loop. This study offers a new ecological perspective on how biological and geochemical connections may have occurred in the chemocline of the Proterozoic ocean, where eukaryotic microbial life is thought to have evolved. IMPORTANCE As a window into the past, this study offers insights into the potential role that microbial guilds may have played in the production and recycling of organic matter in ancient Proterozoic ocean chemoclines. The new observations described here suggest that chloroplasts of eukaryotic algae were persistent in the low-oxygen upper chemocline along with the purple and green sulfur bacteria known to dominate the lower half of the chemocline. This study provides the first insights into Lake Cadagno’s viral ecology. High viral abundances suggested that viruses may be essential components of the chemocline, where their activity may result in the release and recycling of organic matter. The integration of diverse geochemical and biological data types provides a framework that lays the foundation to quantitatively resolve the processes performed by the discrete populations that comprise the microbial loop in this early anoxic ocean analogue.