Foliar development involves successive phases of cell proliferation and expansion that determine the final leaf size, and is characterized by an early burst of reactive oxygen species generated in the photosynthetic electron transport chain (PETC). Introduction of the alternative PETC acceptor flavodoxin in tobacco chloroplasts led to a reduction in leaf size associated to lower cell expansion, without affecting cell number per leaf. Proteomic analysis showed that the biogenesis of the PETC proceeded stepwise in wild-type leaves, with accumulation of light-harvesting proteins preceding that of electron transport components, which might explain the increased energy and electron transfer to oxygen and reactive oxygen species build-up at this stage. Flavodoxin expression did not affect biogenesis of the PETC but prevented hydroperoxide formation through its function as electron sink. Mature leaves from flavodoxin-expressing plants were shown to contain higher levels of transcripts encoding components of the proteasome, a key negative modulator of organ size. Proteome profiling revealed that this differential accumulation was initiated during expansion and led to increased proteasomal activity, whereas a proteasome inhibitor reverted the flavodoxin-dependent size phenotype. Cells expressing plastid-targeted flavodoxin displayed lower endoreduplication, also associated to decreased organ size. These results provide novel insights into the regulation of leaf growth by chloroplast-generated redox signals, and highlight the potential of alternative electron shuttles to investigate the link(s) between photosynthesis and plant development.

N-Acetyl-D-mannosamine (ManNAc) and N-acetylneuraminic acid (Neu5Ac) are important components of glycosylation, affecting numerous physiologic processes. The effects of age, body mass index (BMI), race, or sex on serum levels of ManNAc and Neu5Ac are poorly understood. However, these associations are of substantial interest. Simultaneous quantification of ManNAc and Neu5Ac, using liquid chromatography tandem mass spectrometry (LC-MS/MS), was developed and validated for human serum samples. This method has high sensitivity, specificity, and reproducibility, with limits of detection as low as 1.02 ng/mL for ManNAc or 1.14 ng/mL for Neu5Ac. A set of 155 serum samples from the Adventist Health Study 2 (AHS-2) cohort was analyzed. Concentrations of conjugated Neu5Ac were 35.1 ± 9.4 µg/mL and 33.0 ± 9.5 µg/mL in black and white participants, respectively. Conjugated and total Neu5Ac levels were significantly higher in women, with p-values of 0.029 and 0.026, respectively. The free forms of Neu5Ac were 594 ± 421 ng/mL and 439 ± 168 ng/mL in black and white participants, respectively. Similarly, conjugated and total ManNAc levels were higher in black participants, at 1.81 ± 0.81 µg/mL and 1.90 ± 0.83 µg/mL, compared to 1.32 ± 0.52 µg/mL and 1.41 ± 0.53 µg/mL in white participants (both cases, p < 0.001). Free ManNAc was 93.1 ± 36.2 ng/mL in black and 89 ± 20.2 ng/mL in white participants. Subjects with higher BMI tend to have higher free ManNAc (p = 0.041). Furthermore, older subjects tend to have higher free (p ≤ 0.001) and total (p = 0.045) ManNAc. The improved LC-MS/MS quantification method should facilitate further investigations.

Proteomics is the large scale study of protein structure and function from biological systems through protein identification and quantification. "Shotgun proteomics" or "bottom-up proteomics" is the prevailing strategy, in which proteins are hydrolyzed into peptides that are analyzed by mass spectrometry. Proteomics studies can be applied to diverse studies ranging from simple protein identification to studies of proteoforms, protein-protein interactions, protein structural alterations, absolute and relative protein quantification, post-translational modifications, and protein stability. To enable this range of different experiments, there are diverse strategies for proteome analysis. The nuances of how proteomic workflows differ may be challenging to understand for new practitioners. Here, we provide a comprehensive overview of different proteomics methods to aid the novice and experienced researcher. We cover from biochemistry basics and protein extraction to biological interpretation and orthogonal validation. We expect this work to serve as a basic resource for new practitioners in the field of shotgun or bottom-up proteomics.

Background/Objectives: The association between plasma metabolites derived from dietary substrates and inflammatory processes remains underexplored, despite its potential relevance in the prevention of non-communicable diseases. This systematic review aimed to examine the relationship between blood metabolites and the modulation of inflammatory biomarkers. Methods: A total of 25 randomized controlled trials, published between 2019 and 2024, were included from an initial pool of 111 records. These studies investigated the effects of dietary patterns, specific food groups, or nutritional supplements on the human metabolome and their potential links to inflammation. Results: Metabolomic analyses were predominantly performed using mass spectrometry (MS)-based platforms (17 out of 25), with liquid chromatography–mass spectrometry as the most frequently employed method. Both targeted (n = 14) and untargeted (n = 11) approaches were represented, and samples were drawn from plasma, urine, and feces. Across the interventions, 64 metabolites were modulated, including fatty acyls, glycerolipids, benzenoids, and organic acids, reflecting potential changes in pathways related to oxidative stress, lipid and carbohydrate metabolism, and inflammatory signaling. Several studies also assessed classical inflammatory biomarkers such as C-reactive protein (CRP), tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1). Interventions involving healthy traditional dietary patterns, improvements in dietary fat quality, or the use of specific probiotic strains were often associated with favorable immunometabolic outcomes. In contrast, some interventions, such as Mohana Choorna, elicited upregulation of immune-related gene expression in adipose tissue without improvements in glucose or lipid metabolism. Conclusions: While metabolomic responses varied across studies, the evidence highlights the value of dietary interventions in modulating systemic metabolism and inflammation. These findings support the integration of metabolomics into clinical nutrition to define more personalized and effective dietary strategies for inflammation-related chronic disease prevention.

We developed a comprehensive Diet and Lifestyle Quality Index (DLQI) and examined its associations with health status and sociodemographic characteristics in Argentinian adults. The DLQI scores range from 0 to 100 points and comprises 49 indicators across 7 dimensions: diet and eating habits, physical activity, rest and sleeping habits, exposure to sunlight and nature, religiosity, abstinence from tobacco and alcohol, and emotional well-being and relationships. Cross-sectional data from 4215 adults were analyzed to explore links with sociodemographic characteristics and chronic disease prevalence. Participants’ mean age was 35.5±14.6 years and 69% were women. The mean DLQI score was 51.5±10.6. Higher scores were associated with older age, being married, lower financial concern, rural residence, and receipt of social welfare. Elevated DLQI and dimension-specific scores were inversely related to self-reported obesity, diabetes, fatty liver, hypertension, kidney disease, and cancer, while lower scores were positively associated with overweight and obesity. Score distribution and odds ratios supported cut-off points for classifying lifestyle quality. Our evaluation indicates the DLQI is a practical tool for assessing diverse diet and lifestyle factors, with scores reflecting health status in line with existing evidence. Further evaluation in other populations is recommended to confirm its clinical and public health applicability.

Light significantly influences plant stress responses, with chloroplasts playing a pivotal role as both energy providers and light sensors. They communicate with the nucleus through retrograde signals, including secondary metabolites and reactive oxygen species (ROS). To investigate the contribution of chloroplast redox biochemistry to biotic responses, we studied the interactions of tobacco leaves expressing the alternative electron shuttle flavodoxin with virulent and nonhost Pseudomonas syringae pathovars under light and dark conditions. Flavodoxin is reported to limit light-dependent ROS propagation and over-reduction of the photosynthetic electron transport system under stress. Light intensified the hypersensitive response against the nonhost pathovar tomato (Pto) , but slowed disease progression caused by the virulent pathovar tabaci (Pta) . Flavodoxin mitigated light responses during both interactions, including decreased ROS levels, reduced stromule occurrence, and lower phytoalexin production, with different signatures depending on the pathovar. Similar leaf metabolic profiles were observed in the dark for both strains, with a general up-regulation of sugars, metabolic intermediates, and amino acids. In the light, instead, Pta increased sugars and intermediates, while Pto decreased them. Our results suggest that HR-like responses are elicited in the light even during virulent interactions, and that light effects are related to signals originating at the photosynthetic machinery. Highlights: - Light inhibits disease progression during a tobacco- Pseudomonas virulent interaction. - Light exacerbates the hypersensitive response (HR) during a nonhost interaction. - HR-like responses are elicited in the light even during virulent interactions. - Plastid-targeted flavodoxin decreases plant damage only in photoperiod. - The chloroplast redox state modulates plant biotic response.