Thiamine (vitamin B1) is essential for glucose catabolism. In the yeast species, Nakaseomyces glabratus (formerly Candida glabrata) and Saccharomyces cerevisiae, the transcription factor Pdc2 (with Thi3 and Thi2) upregulates pyruvate decarboxylase (PDC) genes and thiamine biosynthetic and acquisition (THI) genes during starvation. There have not been genome-wide analyses of Pdc2 binding. Previously, we identified small regions of Pdc2-regulated genes sufficient to confer thiamine regulation. Here, we performed deletion analyses on these regions. We observed that when the S. cerevisiae PDC5 promoter is introduced into N. glabratus, it is thiamine starvation inducible but does not require the Thi3 coregulator. The ScPDC5 promoter contains a 22-bp duplication with an AT-rich spacer between the 2 repeats, which are important for regulation. Loss of the first 22-bp element does not eliminate regulation, but the promoter becomes Thi3 dependent, suggesting cis architecture can generate a Thi3-independent, thiamine starvation inducible response. Whereas many THI promoters only have 1 copy of this element, addition of the first 22-bp element to a Thi3-dependent promoter confers Thi3 independence. Finally, we performed fluorescence anisotropy and chromatin immunoprecipitation sequencing. Pdc2 and Thi3 bind to regions that share similarity to the 22-bp element in the ScPDC5 promoter and previously identified cis elements in N. glabratus promoters. Also, while Pdc2 binds to THI and PDC promoters, neither Pdc2 nor Thi3 appears to bind the evolutionarily new NgPMU3 promoter that is regulated by Pdc2. Further study is warranted because PMU3 is required for cells to acquire thiamine from environments where thiamine is phosphorylated, such as in the human bloodstream.

Introduction Chronic metabolic disorders such as diabetes mellitus (DM) are becoming a global health concern. According to recent studies, the pathophysiology of DM may involve factors other than traditional glycemic control, such as electrolyte balance and thiamin status. Therefore, this study evaluated the relationship between sodium and potassium and serum thiamin levels in patients with type 1 and type 2 DM. Methods This study was conducted in multiple diabetic outpatient clinics and centers in Karachi, Pakistan, using a non-probability convenience sampling method. The study lasted for approximately six months after the synopsis was approved. A total of 64 patients were selected, 32 of whom each had type 1 and type 2 DM. All patients who were between the ages of 25 and 46 years old and had either type 1 or type 2 DM were included in the study. A Mann-Whitney test and an independent t-test were used to compare the means between the two study groups. Pearson\'s correlation and chi-square tests were used to determine the variables, correlations, and associations with type 1 and type 2 DM. Results The study findings showed that the distribution of gender among diabetic patients revealed that among males, eight (25.0%) had type 1 DM, and 10 (31.2%) had type 2 DM. Among females, 24 (75.0%) had type 1 DM, and 22 (68.8%) had type 2 DM. Significant correlations were observed in the means of blood glucose levels, such as glycated hemoglobin (HbA1c), fasting blood sugar (FBS), and serum thiamin levels, among patients with type 1 and type 2 DM (p < 0.001). The HbA1c, FBS, and serum thiamin levels were significantly higher in type 2 DM patients than in type 1 DM patients. Among patients with type 1 DM, sodium levels were not substantially correlated with thiamin levels (p = 0.570, r = 0.104), whereas potassium levels were significantly correlated with thiamin levels (p = 0.005, r = 0.263). Conclusion We conclude that the sodium level was not significantly correlated with serum thiamin status in type 1 and type 2 DM, whereas a low positive correlation was observed between potassium and serum thiamin levels in type 1 DM. However, there was no significant correlation concerning potassium levels in type 2 DM.

Introduction Serum urea and creatinine levels are the most commonly recognized parameters for evaluating renal impairment in patients with diabetes mellitus (DM). Therefore, this study evaluated the correlation between urea and creatinine levels and thiamin levels in patients with type 1 DM (T1DM) and type 2 DM (T2DM). Methods This multi-center, cross-sectional study was conducted at diabetic outpatient clinics in Karachi. The duration of the study was six months, from 1st January 2023 to 30th June 2023. A total of 60 patients were enrolled and divided into two groups, i.e., T1DM and T2DM, each containing 30 patients of both genders between the ages of 24 and 42 years. Demographic data and biochemical variables, such as urea, creatinine, random blood sugar, fasting blood sugar, hemoglobin A1c, and serum thiamin levels, were assessed. The Mann-Whitney U test and independent t-test were used to associate the means between the two study groups. The chi-square test and Spearman\'s correlation coefficient were used to determine the associations between the variables and T1DM and T2DM. Results The study results revealed that patients with T2DM had a significantly higher frequency of hypertension (p = 0.039), neuropathy (p = 0.038), and coronary artery disease (p = 0.010) than those with T1DM, in both genders. The level of serum thiamin was found to be significantly higher (p < 0.001) in T2DM (14.8 ± 4.82) than in T1DM patients (7.34 ± 1.90). Similarly, serum creatinine was higher in T2DM than in T1DM patients (0.83 ± 0.12 vs. 0.76 ± 0.17, p = 0.025). Moreover, the correlation of urea and creatinine with thiamin levels in T1DM and T2DM patients revealed that in T1DM and T2DM patients, urea and creatinine showed an insignificant positive correlation with thiamin levels. Conclusion We found a significantly higher level of serum creatinine and thiamin levels in T2DM patients than in T1DM; however, there was no significant correlation between urea and creatinine levels and thiamin status in T1DM and T2DM patients. Therefore, we conclude that although serum urea, creatinine, and serum thiamin are important disease biomarkers in diabetic patients, there is no correlation between them.

Legumes have been recognised as healthy and environmentally friendly protein sources. Knowledge about the vitamin B contents in legume ingredients and extrudates is scarce. In this study, we investigated thiamin, riboflavin, niacin, and folate in various faba bean, lupin, and pea ingredients. Further, the retention of B vitamins in high moisture extrusion was studied. Prior to liquid chromatographic determinations of thiamin, riboflavin, niacin, and folate, vitamins were extracted by acid hydrolysis (niacin), enzymatic treatment (folate), or their combination (thiamin and riboflavin). The contents (on a dry matter basis) varied greatly among different ingredients: the thiamin content was 0.2-14.2 µg/g; riboflavin, 0.3-5.9 µg/g; niacin, 8.8-35.5 µg/g, and folate, 45-1453 ng/g. Generally, the highest levels were in flours and protein concentrates, whereas low levels were observed in isolates. The retention of B vitamins was excellent in high moisture extrusion, except for folate in faba bean, where the folate contents were 42-67% lower in the extrudates than in the respective ingredient mixtures. In terms of both vitamin B contents and their retention, extrudates containing substantial amounts of flour or protein concentrate are promising plant-based sources of thiamin, riboflavin, niacin, and folate.

Vitamin B1 (thiamin, B1) is an essential micronutrient for cells, yet intriguingly in aquatic systems most bacterioplankton are unable to synthesize it de novo (auxotrophy), requiring an exogenous source. Cycling of this valuable metabolite in aquatic systems has not been fully investigated and vitamers (B1-related compounds) have only begun to be measured and incorporated into the B1 cycle. Here, we identify potential key producers and consumers of B1 and gain new insights into the dynamics of B1 cycling through measurements of B1 and vitamers (HMP: 4-amino-5-hydroxymethyl-2-methylpyrimidine, HET: 4-methyl-5-thiazoleethanol, FAMP: N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine) in the particulate and dissolved pool in a temperate coastal system. Dissolved B1 was not the primary limiting nutrient for bacterial production and was relatively stable across seasons with concentrations ranging from 74-117 pM, indicating a balance of supply and demand. However, vitamer concentration changed markedly with season as did transcripts related to vitamer salvage and transport suggesting use of vitamers by certain bacterioplankton, e.g. Pelagibacterales. Genomic and transcriptomic analyses showed that up to 78% of the bacterioplankton taxa were B1 auxotrophs. Notably, de novo B1 production was restricted to a few abundant bacterioplankton (e.g. Vulcanococcus, BACL14 (Burkholderiales), Verrucomicrobiales) across seasons. In summer, abundant picocyanobacteria were important putative B1 sources, based on transcriptional activity, leading to an increase in the B1 pool. Our results provide a new dynamic view of the players and processes involved in B1 cycling over time in coastal waters, and identify specific priority populations and processes for future study.

Vitamin B1 (thiamin) is a vital nutrient for most cells in nature, including marine plankton. Early and recent experiments show that B1 degradation products instead of B1 can support the growth of marine bacterioplankton and phytoplankton. However, the use and occurrence of some degradation products remains uninvestigated, namely N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine (FAMP), which has been a focus of plant oxidative stress research. We investigated the relevance of FAMP in the ocean. Experiments and global ocean meta-omic data indicate that eukaryotic phytoplankton, including picoeukaryotes and harmful algal bloom species, use FAMP while bacterioplankton appear more likely to use deformylated FAMP, 4-amino-5-aminomethyl-2-methylpyrimidine. Measurements of FAMP in seawater and biomass revealed that it occurs at picomolar concentrations in the surface ocean, heterotrophic bacterial cultures produce FAMP in the dark-indicating non-photodegradation of B1 by cells, and B1-requiring (auxotrophic) picoeukaryotic phytoplankton produce intracellular FAMP. Our results require an expansion of thinking about vitamin degradation in the sea, but also the marine B1 cycle where it is now crucial to consider a new B1-related compound pool (FAMP), as well as generation (dark degradation-likely via oxidation), turnover (plankton uptake), and exchange of the compound within the networks of plankton. IMPORTANCE Results of this collaborative study newly show that a vitamin B1 degradation product, N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine (FAMP), can be used by diverse marine microbes (bacteria and phytoplankton) to meet their vitamin B1 demands instead of B1 and that FAMP occurs in the surface ocean. FAMP has not yet been accounted for in the ocean and its use likely enables cells to avoid B1 growth deficiency. Additionally, we show FAMP is formed in and out of cells without solar irradiance-a commonly considered route of vitamin degradation in the sea and nature. Altogether, the results expand thinking about oceanic vitamin degradation, but also the marine B1 cycle where it is now crucial to consider a new B1-related compound pool (FAMP), as well as its generation (dark degradation-likely via oxidation), turnover (plankton uptake), and exchange within networks of plankton.

Homogenates of brain tissue from the frontal cortex at autopsy in patients with amyotrophic lateral sclerosis (ALS) showed dramatically reduced levels of the enzyme thiamine pyrophosphatase (TPPase), the enzyme responsible for the conversion of thiamine pyrophosphate (TPP) to thiamine monophosphate (TMP). Additionally, free thiamine (vitamin B1) and TMP levels have been shown to be significantly reduced in the plasma and cerebral spinal fluid (CSF) of patients with ALS. These findings suggest that there is impaired thiamine metabolism in patients with ALS. Impaired thiamine metabolism decreases adenosine triphosphate (ATP) production and is a well-established cause of neurodegeneration. Decreased levels of TPPase, resulting in decreased levels of TMP in the cells of the frontal cortex, might account for the focal neurodegenerative changes observed in motor neurons in ALS. Benfotiamine, a safe, lipid-soluble, highly absorbable thiamine analogue, significantly raises free thiamine, TMP, and TPP levels in the blood. A case in which benfotiamine may have positively impacted the symptoms of a patient with ALS is presented. The use of benfotiamine in patients with ALS appears to be a promising therapeutic option. Considering the severity and the lack of satisfactory treatment options associated with this disease, more research on the effects of benfotiamine on the course of ALS is urgently needed.

UNASSIGNED: Rigid cans were the traditional container for canned cat foods, but semi-rigid trays/tubs and flexible pouches are popular options as well. Despite this, little is published on the effects of canned cat food container characteristics on thermal processing and retention of B-vitamins. Therefore, the objective was to evaluate the effects of container size and type on thermal processing and B-vitamin retention.
UNASSIGNED: Treatments were arranged in a factorial with two container sizes [small (85-99 g) and medium (156-198 g)] and three container types (flexible, semi-rigid, and rigid). A canned cat food formula was prepared, filled, and sealed into containers before retort processing to a heating cycle target lethality of 8 min. Internal retort and container temperatures were used to calculate accumulated lethality. Thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid, cobalamin, and moisture contents were analyzed in pre- and post-retort samples by commercial laboratories. Thermal processing metrics were analyzed (SAS v. 9.4; SAS Institute, Cary, NC) with the fixed effects of container size, container type, and their interaction. Dry matter basis B-vitamin contents were analyzed with container size, container type, processing stage, and all two-way and three-way interactions as fixed effects. Means were separated using Fisher\'s LSD at a P-value < 0.05.
UNASSIGNED: Total accumulated lethality was greater (P < 0.05) for semi-rigid and flexible containers (average 14.99 min) than for rigid containers (12.86 min). The greater processing of semi-rigid and flexible containers was likely influenced by required retort settings. Thiamin and riboflavin contents decreased (P < 0.05) by 30.4 and 18.3%, respectively, due to retort processing. Niacin, biotin, and cobalamin were not affected (P > 0.05) by processing. Processing increased (P < 0.05) pantothenic acid (9.1%), pyridoxine (22.6%), and folic acid (22.6%). This was likely caused by sampling or analytical variation. No interaction involving processing stage was significant for any B-vitamin (P > 0.05). B-vitamin retention was not influenced by differences in thermal processing caused by the packaging treatments. Thiamin and riboflavin were the only B-vitamins meaningfully impacted by processing and retention was not improved by any container characteristic.

TenA thiamin-degrading enzymes are commonly found in prokaryotes, plants, fungi and algae and are involved in the thiamin salvage pathway. The gut symbiont Bacteroides thetaiotaomicron (Bt) produces a TenA protein (BtTenA) which is packaged into its extracellular vesicles. An alignment of BtTenA protein sequence with proteins from different databases using the basic local alignment search tool (BLAST) and the generation of a phylogenetic tree revealed that BtTenA is related to TenA-like proteins not only found in a small number of intestinal bacterial species but also in some aquatic bacteria, aquatic invertebrates, and freshwater fish. This is, to our knowledge, the first report describing the presence of TenA-encoding genes in the genome of members of the animal kingdom. By searching metagenomic databases of diverse host-associated microbial communities, we found that BtTenA homologues were mostly represented in biofilms present on the surface of macroalgae found in Australian coral reefs. We also confirmed the ability of a recombinant BtTenA to degrade thiamin. Our study shows that BttenA-like genes which encode a novel sub-class of TenA proteins are sparingly distributed across two kingdoms of life, a feature of accessory genes known for their ability to spread between species through horizontal gene transfer.

Sulfide-dependent THI4 thiazole synthases could potentially be used to replace plant cysteine-dependent suicide THI4s, whose high protein turnover rates make thiamin synthesis exceptionally energy-expensive. However, sulfide-dependent THI4s are anaerobic or microoxic enzymes and hence unadapted to the aerobic conditions in plants; they are also slow enzymes (kcat < 1 h-1). To improve aerotolerance and activity, we applied continuous directed evolution under aerobic conditions in the yeast OrthoRep system to two sulfide-dependent bacterial THI4s. Seven beneficial single mutations were identified, of which five lie in the active-site cleft predicted by structural modeling and two recapitulate features of naturally aerotolerant THI4s. That single mutations gave substantial improvements suggests that further advance under selection will be possible by stacking mutations. This proof-of-concept study established that the performance of sulfide-dependent THI4s in aerobic conditions is evolvable and, more generally, that yeast OrthoRep provides a plant-like bridge to adapt nonplant enzymes to work better in plants.