Mechanism of organic phosphorus transformation and its impact on the primary production in a deep oligotrophic plateau lake during stratification.

Global warming is leading to extended stratification in deep lakes, which may exacerbate phosphorus (P) limitation in the upper waters. Conversion of labile dissolved organic P (DOP) is a possible adaptive strategy to maintain primary production. To test this, the spatiotemporal distributions of various soluble P fractions and phosphomonesterase (PME)/phosphodiesterase (PDE) activities were investigated in Lake Fuxian during the stratification period and the transition capacity of organic P and its impact on primary productivity were evaluated. The results indicated that the DOP concentration (mean 0.20 ± 0.05 µmol L-1) was significantly higher than that of dissolved inorganic P (DIP) (mean 0.08 ± 0.03 µmol L-1) in the epilimnion and metalimnion, which were predominantly composed of orthophosphate monoester (monoester-P) and orthophosphate diesters (diester-P). The low ratio of diester-P / monoester-P and high activities of PME and PDE indicate DOP mineralization in the epilimnion and metalimnion. We detected a DIP threshold of approximately 0.19 µmol L-1, corresponding to the highest total PME activity in the lake. Meta-analysis further demonstrated that DIP thresholds of PME activities were prevalent in oligotrophic (0.19 µmol L-1) and mesotrophic (0.74 µmol L-1) inland waters. In contrast to the phosphate-sensitive phosphatase PME, dissolved PDE was expressed independent of phosphate availability and its activity invariably correlated with chlorophyll a, suggesting the involvement of phytoplankton in DOP utilization. This study provides important field evidence for the DOP transformation processes and the strategy for maintaining primary productivity in P-deficient scenarios, which contributes to the understanding of P cycles and the mechanisms of system adaptation to future long-term P limitations in stratified waters.

Effect of early preventive supplementation with calcium and phosphorus on metabolic bone disease in premature infants.

OBJECTIVE: The objective was to study the effect of early preventive calcium and phosphorus supplementation on metabolic bone disease in preterm infants. METHODS: A retrospective analysis of 234 preterm infants with a gestational age < 32 weeks or birth weight < 1500 g who were hospitalized in the Neonatology Department of the Second Hospital of Shandong University from 01.2018 to 12.2020 was conducted. One hundred thirty-two premature infants hospitalized from 01.2018 to 06.2019 did not receive prophylactic calcium and phosphorus supplementation in the early postnatal period. These infants received calcium or phosphorus supplementation at the time of hypocalcaemia or hypophosphatemia diagnosis. One hundred two premature infants hospitalized from 07.2019 to 12.2020 received early preventive calcium and phosphorus supplementation after birth. The levels of serum calcium and phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, calcitonin, and parathyroid hormone at different time points and growth indicators at six months of age were compared between the two groups of infants. The number of cases of metabolic bone disease and fracture between the two groups was compared. RESULTS: 1) A total of 12 infants (5.13%) among the 234 preterm infants were diagnosed with metabolic bone disease, including 2 (1.96%) in the prophylactic supplementation group and 10 (7.58%) in the nonprophylactic supplementation group. Fractures occurred in 3 premature infants (25.0%) with metabolic bone disease, all of whom were in the group that did not receive prophylactic supplementation. 2) There was no significant difference in serum calcium and calcitonin levels between the two groups. The levels of serum phosphorus and 25 hydroxyvitamin D in the prophylactic supplementation group were higher than those in the nonprophylactic supplementation group (P < 0.05). In comparison, alkaline phosphatase and parathyroid hormone levels were lower in the prophylactic supplementation group than in the nonprophylactic supplementation group (P < 0.05). Preterm infants in the prophylactic supplementation group had higher weight, length, head circumference, and bone density values than those in the nonprophylactic supplementation group (P < 0.05). CONCLUSION: Preventive supplementation with calcium and phosphorus after birth can effectively improve calcium and phosphorus metabolism, and reduce the incidence of metabolic bone disease and fractures in premature infants. This can be further publicized and used clinically.

Persistence of Chronic Lymphocytic Leukemia Stem-like Populations under Simultaneous In Vitro Treatment with Curcumin, Fludarabine, and Ibrutinib: Implications for Therapy Resistance.

Leukemic stem cells (LSCs) possess similar characteristics to normal hematopoietic stem cells, including self-renewal capacity, quiescence, ability to initiate leukemia, and drug resistance. These cells play a significant role in leukemia relapse, persisting even after apparent remission. LSCs were first described in 1994 by Lapidot et al. Although they have been extensively studied in acute leukemia, more LSC research is still needed in chronic lymphocytic leukemia (CLL) to understand if reduced apoptosis in mature cells should still be considered as the major cause of this disease. Here, we provide new evidence suggesting the existence of stem-like cell populations in CLL, which may help to understand the disease as well as to develop effective treatments. In this study, we identified a potential leukemic stem cell subpopulation using the tetraploid CLL cell line I83. This subpopulation is characterized by diploid cells that were capable of generating the I83 tetraploid population. Furthermore, we adapted a novel flow cytometry analysis protocol to detect CLL subpopulations with stem cell properties in peripheral blood samples and primary cultures from CLL patients. These cells were identified by their co-expression of CD19 and CD5, characteristic markers of CLL cells. As previously described, increased alkaline phosphatase (ALP) activity is indicative of stemness and pluripotency. Moreover, we used this method to investigate the potential synergistic effect of curcumin in combination with fludarabine and ibrutinib to deplete this subpopulation. Our results confirmed the effectiveness of this ALP-based analysis protocol in detecting and monitoring leukemic stem-like cells in CLL. This analysis also identified limitations in eradicating these populations using in vitro testing. Furthermore, our findings demonstrated that curcumin significantly enhanced the effects of fludarabine and ibrutinib on the leukemic fraction, exhibiting synergistic effects (combination drug index, CDI 0.97 and 0.37, respectively). Our results lend support to the existence of potential stem-like populations in CLL cell lines, and to the idea that curcumin could serve as an effective adjuvant in therapies aimed at eliminating these populations and improving treatment efficacy.

The hepatoprotective potentials of Olea europaea L. leaves against carbon tetrachloride-induced hepatic injury in rats.

OBJECTIVE: To examine the therapeutic effects of Olea europaea L. leaves extract on carbon tetrachloride-induced liver injury in rats. Methods: The experimental study was conducted at the Department of Physiology, University of Karachi, Karachi, in July 2021, and comprised Albino Wistar male rats weighing 180-220gm. The animals were divided into control group I, carbon tetrachloride group II, Olea europaea L. + carbon tetrachloride group III and Olea europaea L. group IV. In Vitro model of hepatic toxicity was developed by carbon tetrachloride. A daily dose of 50mg/kg of aqueous extract of olive leaves was administered orally and 0.8ml/kg of carbon tetrachloride was administered twice a week subcutaneously for 28 days. On the 29th day, the animals were sacrificed, and tested for hepatic enzymes, lipid peroxidation markers and histopathology. Data was analysed using SPSS 20. RESULTS: Of the 24 rats, 6(25%) were in each of the 4 groups. Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin levels were significantly reduced (p<0.05) in group II whereas, 4- hydroxynonenal, isoprostane and malondialdehyde levels were significantly increased (p<0.05). However, total antioxidant level increased significantly (p<0.05) in group III compared to group II. Histopathology showed severe liver damage in group II and mild damage in group III. Conclusion: Olea europaea L. leaves extract was found to have profound hepatoprotective effects.

Pyridoxine challenge reflects pediatric hypophosphatasia severity and thereby examines tissue-nonspecific alkaline phosphatase's role in vitamin B6 metabolism.

Alkaline phosphatase (ALP) is detected in most human tissues. However, ALP activity is routinely assayed using high concentrations of artificial colorimetric substrates in phosphate-free laboratory buffers at lethal pH. Hypophosphatasia (HPP) is the inborn-error-of-metabolism caused by loss-of-function mutation(s) of the ALPL gene that encodes the ALP isoenzyme expressed in bone, liver, kidney, and elsewhere and is therefore designated "tissue-nonspecific" ALP (TNSALP). Consequently, HPP harbors clues concerning the biological function of this phosphohydrolase that is anchored onto the surface of cells. The biochemical signature of HPP features low serum ALP activity (hypophosphatasemia) together with elevated plasma levels of three natural substrates of TNSALP: i) phosphoethanolamine (PEA), a component of the linkage apparatus that binds ALPs and other proteins to the plasma membrane surface; ii) inorganic pyrophosphate (PPi), an inhibitor of bone and tooth mineralization; and iii) pyridoxal 5'-phosphate (PLP), the principal circulating vitameric form of vitamin B6 (B6). Autosomal dominant and autosomal recessive inheritance involving several hundred ALPL mutations underlies the remarkably broad-ranging expressivity of HPP featuring tooth loss often with muscle weakness and rickets or osteomalacia. Thus, HPP associates the "bone" isoform of TNSALP with biomineralization, whereas the physiological role of the "liver", "kidney", and other isoforms of TNSALP remains uncertain. Herein, to examine HPP's broad-ranging severity and the function of TNSALP, we administered an oral challenge of pyridoxine (PN) hydrochloride to 116 children with HPP. We assayed both pre- and post-challenge serum ALP activity and plasma levels of PLP, the B6 degradation product pyridoxic acid (PA), and the B6 vitamer pyridoxal (PL) that can enter cells. Responses were validated by PN challenge of 14 healthy adults and 19 children with metabolic bone diseases other than HPP. HPP severity was assessed using our HPP clinical nosology and patient height Z-scores. PN challenge of all study groups did not alter serum ALP activity in our clinical laboratory. In HPP, both the post-challenge PLP level and the PLP increment correlated (Ps < 0.0001) with the clinical nosology and height Z-scores (Rs = +0.6009 and + 0.4886, and Rs = -0.4846 and - 0.5002, respectively). In contrast, the plasma levels and increments of PA and PL from the PN challenge became less pronounced with HPP severity. We discuss how our findings suggest extraskeletal TNSALP primarily conditioned the PN challenge responses, and explain why they caution against overzealous B6 supplementation of HPP.

Dietary 25 Hydroxyvitamin D3 Improved Serum Concentration Level and Alkaline Phosphatase Activity during Lactation but Had Meager Impact on Post-Farrowing Reproductive Performance in Sows.

Dietary 25 hydroxyvitamin D3 (25(OH)D3) promotes serum 25(OH)D3 concentration and alkaline phosphatase activity (ALP); however, post-farrowing reproductive performance of lactating sows fed with 14-epimer of 25(OH)D3 is uncertain. This study investigated post-farrowing reproductive performance, serum ALP activity, and serum 25(OH)D3 concentration in sows fed VD3, 25(OH)D3, or 14-epi 25(OH)D3. Weaned sows (n = 203) in parities 2 and 3 were blocked weekly and treated with 2000 IU/kg VD3 (T1), 25 µg/kg 25(OH)D3:14-epi 25(OH)D3 (T2), or 50 µg/kg 25(OH)D3 (T3) diets, all equilibrated to 2000 IU/kg as fed. Sow performance, treatment, and sampling period effects were analyzed. Environmental conditions were analyzed as covariates. The number of piglets weaned (p = 0.029), pre-weaning mortality (p = 0.029), sampling period (p < 0.001), and treatment and period interaction (p = 0.028) differed significantly. There was an increase in 25(OH)D3 during lactation due to physiological demands for milk calcium and milk production. Supplementing twice the concentration of 25(OH)D3 compared to its epimer, 25(OH)D3:14-epi 25(OH)D3, had no significant effect on the post-farrowing reproductive performance of lactating sows. The effect of 25(OH)D3 on post-farrowing reproductive performance and ALP activity in sows was influenced by metabolic demand for calcium due to physiological changes during lactation as well as epimer conformation.

Effect of vitamin D supplementation or fortification on bone turnover markers in women: a systematic review and meta-analysis.

Vitamin D is a vital indicator of musculoskeletal health, as it plays an important role through the regulation of bone and mineral metabolism. This meta-analysis was performed to investigate the effects of vitamin D supplementation/fortification on bone turnover markers in women. All human randomised clinical trials reported changes in bone resorption markers (serum C-terminal telopeptide of type-I collagen (sCTX) and urinary type I collagen cross-linked N-telopeptide (uNTX)) or bone formation factors (osteocalcin (OC), bone alkaline phosphatase (BALP) and procollagen type-1 intact N-terminal propeptide (P1NP)) following vitamin D administration in women (aged ≥ 18 years) were considered. Mean differences (MD) and their respective 95 % CI were calculated based on fixed or random effects models according to the heterogeneity status. Subgroup analyses, meta-regression models, sensitivity analysis, risk of bias, publication bias and the quality of the included studies were also evaluated. We found that vitamin D supplementation had considerable effect on sCTX (MD: -0·038, n 22) and OC (MD: -0·610, n 24) with high heterogeneity and uNTX (MD: -8·188, n 6) without heterogeneity. Our results showed that age, sample size, dose, duration, baseline vitamin D level, study region and quality of studies might be sources of heterogeneity in this meta-analysis. Subgroup analysis also revealed significant reductions in P1NP level in dose less than 600 µg/d and larger study sample size (>100 participants). Moreover, no significant change was found in BALP level. Vitamin D supplementation/fortification significantly reduced bone resorption markers in women. However, results were inconsistent for bone formation markers.

Protective Properties of Intestinal Alkaline Phosphatase Supplementation on the Intestinal Barrier: Interactions and Effects.

The intestinal barrier is critical for maintaining intestinal homeostasis, and its dysfunction is associated with various diseases. Recent findings have revealed the multifunctional role of intestinal alkaline phosphatase (IAP) in diverse biological processes, including gut health maintenance and function. This review summarizes the protective effects of IAP on intestinal barrier integrity, encompassing the physical, chemical, microbial, and immune barriers. We discuss the results and insights from in vitro, animal model, and clinical studies as well as the available evidence regarding the impact of diet on IAP activity and expression. IAP can also be used as an indicator to assess intestinal-barrier-related diseases. Further research into the mechanisms of action and long-term health effects of IAP in maintaining overall intestinal health is essential for its future use as a dietary supplement or functional component in medical foods.

Streptomyces rock phosphate ore biomining evaluation in vitro.

The process of extracting metals from rock phosphate ore (RPO) by using microorganisms to convert them into soluble compounds is called biomining. Phosphorus is one of the elements proposed to be extracted from RPO. To understand the role of Streptomyces phospholyticus, 12 isolates of Streptomyces were isolated from RPO, their ability to grow on specific phosphate solubilization medium e.g., National Botanical Research Institute's phosphate growth agar (NBRIP) was studied, and the best strain with a 3 cm clear zone was selected. Its ability to grow at increasing RPO concentrations from 0.01 to 1 kgl-1 was investigated. This strain showed good growth, with extracellular red pigmentation for all concentrations, but no clear zone. In the modified liquid NBRIP, however, the Streptomyces growth patterns of the two concentrations of 0.25 kg and 1 kgl-1 RPO showed growth of single spherical red colonies with rhizoids on the surface, the colonies somehow grew and became embedded in the fine RPO granules. This ability to grow can resist gamma irradiation with a dose of 32 KGy. Within 3 days of growth, acidic and alkaline phosphatase were 76.2 and 67.1 µg p-nitrophenol g-1 ml-1, respectively. The RPO analysis showed that the %P in the ore was 16.5% at the beginning of the experiment, and after Streptomyces biotreatment, this percentage decreased to 8.4%, with a decomposition rate of 50.7%. This study, to our knowledge, is the first to investigate the efficiency of Streptomyces in mining phosphate rock ore in the laboratory, even at high concentrations, and to examine the role of irradiation as a preservative in increasing this efficiency.

Benthic primary production decreases internal phosphorus loading from lake sediments under light supplement.

In aquatic ecosystems, light penetrating the sediment surface in shallow lakes may regulate the internal phosphorus (P) release through benthic primary production, which subsequently affects oxidation, pH levels, and alkaline phosphatase activity in the upper sediment. To study the effects of light exposure on the P dynamics at the sediment-water interface under eutrophic conditions, a two-month mesocosm experiment was conducted in twelve cement tanks (1000 L each). The tanks were equipped with Light-Emitting Diode (LED) lights, and surface sediments collected from eutrophic Lake Nanhu (China) were exposed to four different light intensities (0, 50, 100, 200 µmol m-2 s-1). The results revealed that: 1) Both the total phosphorus concentration and the phosphorus release flux from the sediment were lower in the light treatments (mean value, 0.59-0.71 mg L-1 and 0.00-0.01 mg m-2 d-1, respectively) than in the control treatment (0.77 mg L-1 and 0.01 mg m-2 d-1, respectively), indicating that light supplement could decrease the internal P release. 2) Benthic primary production promoted by light directly absorbed soluble reactive phosphorus and decreased the internal P release. The resulting improved production could also increase dissolved oxygen concentrations at the sediment-water interface, thus indirectly inhibiting internal P release. 3) The relative contributions of direct absorption and indirect inhibition on the internal P release ranged between 23% to 69% and 31% to 77% depending on the light intensity.

Coupling of cylindrospermopsin and pho-harboring Verrucomicrobia supports the formation of Raphidiopsis blooms in low-phosphorus waters.

Cylindrospermopsin (CYN) can induce phytoplankton community to secrete alkaline phosphatase (ALP), which is one of the important strategies for the bloom-forming cyanobacterium Raphidiopsis to thrive in extremely low-phosphorus (P) waters. However, how bacterioplankton community, another major contributor to ALPs in waters, couples to Raphidiopsis through CYN, and the role of this coupling in supporting the dominance of Raphidiopsis in nature remain largely unknown. Here, we conducted microcosm experiments to address this knowledge gap, using a combination of differential filtration-based and metagenomics-based methods to identify the sources of ALPs. We found that, compared with algal-derived ALPs, bacteria-derived ALPs exhibited a more pronounced and sensitive response to CYN. This response to CYN was enhanced under low-P conditions. Interestingly, we found that Verrucomicrobia made the largest contribution to the total abundance of pho genes, which encode ALPs. Having high gene abundance of the CYN-sensing PI3K-AKT signaling pathway, Verrucomicrobia's proportion increased with higher concentrations of CYN under low-P conditions, thereby explaining the observed increase in pho gene abundance. Compared with other cyanobacterial genera, Raphidiopsis had a higher abundance of the pst gene. This suggests that Raphidiopsis exhibited a greater capacity to uptake the inorganic P generated by ALPs secreted by other organisms. Overall, our results reveal the mechanism of CYN-induced ALP secretion and its impact on planktonic P-cycling, and provide valuable insights into the role of CYN in supporting the formation of Raphidiopsis blooms.

Effects of Zinc-Gluconate Levels on Growth Performance, Whole-Body Composition, and Mineral and Enzyme Activities of Juvenile Mori (Cirrhinus mrigala).

Zinc (Zn) is an important dietary nutrient for the optimum growth performance, feed efficiency, normal metabolism, and fish health. Unfortunately, Zn requirement for mori (Cirrhinus mrigala) is not available. This experiment was designed to assess the impacts of Zn-gluconate levels on growth performance, feed utilization, mineral composition, and enzyme activities of mori and determines the optimum requirement of Zn-gluconate for this species. For this purpose, seven isonitrogenous (29.18%) and isolipidic (10.71%) purified diets were formulated with graded Zn-gluconate levels (0, 10, 20, 30, 40, 50, and 60 mg/kg). A total of 525 juveniles (4.30 ± 0.13 g) were distributed in 21 tanks. All treatments were assessed in triplicates. At the end of the trial (90 days), a progressive increase in final weight (FW) was observed in mori fed with 0-40 mg/kg of Zn-gluconate, remained constant at 50 mg/kg of Zn-gluconate, and significantly decreased at 60 mg/kg of Zn-gluconate. Similarly, weight gain and specific growth rate followed a similar pattern, while weight gain% increased till 40 mg/kg of Zn-gluconate. However, further increase (40-60 mg/kg) had a non-significant effect on weight gain%. Diet supplemented with 40 mg/kg of Zn-gluconate resulted in optimum values for feed intake and feed conversion ratio. Supplementation of Zn-gluconate did not affect dry matter, crude fat, and crude ash at all graded levels. However, whole body crude protein was significant in response to Zn-gluconate supplementation. Furthermore, Zn-gluconate absorption enhanced from 0 to 40 mg/kg of Zn-gluconate and remained constant afterward. Whole body mineral activity also followed a similar pattern. Overall, Zn-gluconate supplementation enhanced (P < 0.05) mineral activity in all parts of the tested parts of mori, including bones, scales, skin, eyes, heart, liver, and kidney. Moreover, the highest (P < 0.05) mineral activity in the skin, heart, liver, and kidney was observed in 60 mg/kg of Zn-gluconate. Supplementation of Zn-gluconate significantly increased the activity of alkaline phosphatase while it reduced thiobarbituric acid reactive substance contents of mori. The optimal dietary requirement of Zn-gluconate was recorded as 43.86 mg/kg through broken-line regression for maximum weight gain% of mori juveniles. Conclusively, 40 mg/kg of Zn-gluconate supplementation significantly enhanced the health of C. mrigala. However, a further increase in Zn-gluconate supplementation from 40 to 60 mg/kg did not significantly improve the above-mentioned parameters.

Estimating Vitamin D threshold for the Indian population: Delving into the actual disease burden.

Background: Based on the current guidelines in practice, a vast majority of the healthy Indian population is vitamin D deficient. Since the serum 25 hydroxycholecalciferol (25HCC) levels are affected by race and skin pigmentation, the normal range of vitamin D may differ in the Indians compared to the Western population. This study attempted to determine a population-specific threshold for 25 HCC levels associated with adequate bone health and calcium and phosphate homeostasis in healthy Indians. Methods: Subjects aged 20-50 years were included in the study. The exclusion criteria were obesity, chronic renal disease, liver failure, diabetes mellitus, thyroid disorders, a recent history of fracture, constant joint pain, and postmenopausal status. In addition, participants on prescribed medication such as glucocorticoids, anticonvulsants, or antifungals, as well as vitamin D and calcium supplementation, were also excluded.Blood samples were analyzed for serum calcium, phosphate, alkaline phosphatase, 25HCC, 1,25dihydroxycholecalciferol, parathyroid hormone (PTH), procollagen type-I N propeptide, and C-terminal telopeptide of type 1 collagen.Locally estimated smoothing scatter plot (LOESS) curves and Spearman correlation were utilized to study the correlation of all the biochemical parameters with 25 HCC to achieve thresholds. Results: The study consisted of 270 healthy participants, out of which 97.8% were found to have vitamin D levels below 30 ng/ml. In addition, 8.8% had raised PTH, and 1.85% had hypocalcemia. Furthermore, 1.48% had raised serum alkaline phosphatase and hypophosphatemia, respectively. A weak inverse correlation was seen between 25 HCC and PTH (rs = -0.437, p < 0.001), as well as alkaline phosphatase (rs = -0.1475, p = 0.015), while a weak positive correlation was seen with serum phosphate (rs = 0.128, p = 0.047). Conclusion: For a healthy Indian population, the reference range of 25 HCC is much lower, and the lower limit of normal is approximately 13.5 ng/ml. This study indicates that vitamin D insufficiency in this population starts at 25 HCC values of 13.5 ng/ml and deficiency at 7 ng/ml.

Alkaline Phosphatase PhoD Mutation Induces Fatty Acid and Long-Chain Polyunsaturated Fatty Acid (LC-PUFA)-Bound Phospholipid Production in the Model Diatom Phaeodactylum tricornutum.

With rapid growth and high lipid contents, microalgae have become promising environmentally friendly candidates for renewable biodiesel and health supplements in our era of global warming and energy depletion. Various pathways have been explored to enhance algal lipid production, especially gene editing. Previously, we found that the functional loss of PhoD-type alkaline phosphatase (AP), a phosphorus-stress indicator in phytoplankton, could lead to increased lipid contents in the model diatom Phaeodactylum tricornutum, but how the AP mutation may change lipid composition remains unexplored. This study addresses the gap in the research and investigates the effects of PhoD-type AP mutation on the lipid composition and metabolic regulation in P. tricornutum using transcriptomic and lipidomic analyses. We observed significantly modified lipid composition and elevated production of fatty acids, lysophosphatidylcholine, lysophosphatidylethanolamine, ceramide, phosphatidylinositol bisphosphate, and monogalactosylmonoacylglycerol after PhoD_45757 mutation. Meanwhile, genes involved in fatty acid biosynthesis were upregulated in mutant cells. Moreover, the mutant exhibited increased contents of ω-3 long-chain polyunsaturated fatty acid (LC-PUFA)-bound phospholipids, indicating that PhoD_45757 mutation could improve the potential bioavailability of PUFAs. Our findings indicate that AP mutation could influence cellular lipid synthesis and probably redirect carbon toward lipid production and further demonstrate that AP mutation is a promising approach for the development of high-value microalgal strains for biomedical and other applications.

Species-dependent effects of seawater acidification on alkaline phosphatase activity in dinoflagellates.

Increases of atmospheric CO2 cause ocean acidification (OA) and global warming, the latter of which can stratify the water column and impede nutrient supply from deep water. Phosphorus (P) is an essential nutrient for phytoplankton to grow. While dissolved inorganic phosphorus (DIP) is the preferred form of P, phytoplankton have evolved alkaline phosphatase (AP) to utilize dissolved organic phosphorus (DOP) when DIP is deficient. Although the function of AP is known to require pH > 7, how OA affects AP activity and hence the capacity of phytoplankton to utilize DOP is poorly understood. Here, we examined the effects of pH conditions (5.5-11) on AP activity from six species of dinoflagellates, an important group of marine phytoplankton. We observed a general pattern that AP activity declined sharply at pH 5.5, peaked between pH 7 and 8, and dropped at pH > 8. However, our data revealed remarkable interspecific variations in optimal pH and niche breadth of pH. Among the species examined, Fugacium kawagutii and Prorocentrum cordatum had an optimal pH at 8, and Alexandrium pacificum, Amphidinium carterae, Effrenium voratum, and Karenia mikimotoi showed an optimal pH of 7. However, whereas A. pacificum and K. mikimotoi had the broadest pH niche for AP (7-10) and F. kawagutii the second (8-10), Am. carterae, E. voratum, and P. cordatum exhibited a narrow pH range. The response of Am. carterae AP to pH changes was verified using purified AP heterologously expressed in Escherichia coli. These results in concert suggest OA will likely differentially impact the capacity of different phytoplankton species to utilize DOP in the projected more acidified and nutrient-limited future ocean.

Risk factors for the comorbidity of osteoporosis/osteopenia and kidney stones: a cross-sectional study.

Low femoral neck bone mineral density (BMD) was associated with the increased risk of kidney stones. Low dietary magnesium intake and increased serum alkaline phosphatase were associated with the increased risk of low femoral neck BMD in kidney stone formers. PURPOSE: To evaluate whether low femoral neck bone mineral density (BMD) was associated with a higher risk of kidney stones, and identify risk factors for the comorbidity of osteoporosis/osteopenia and kidney stones. METHODS: We analyzed individuals aged ≥ 20 years from National Health and Nutrition Examination Survey 2007-2020 data. Osteoporosis/osteopenia is defined as any T-score < -1.0 of femoral neck, total femoral, and mean lumbar spine (L1-L4) BMD. Dietary intakes (sodium, potassium, magnesium, calcium, phosphorus, calcium/phosphorus, vitamin D (25OHD2+25OHD3)) and serum parameters (sodium, potassium, calcium, phosphorus, bicarbonate, vitamin D, alkaline phosphatase (ALP)) were screened for identifying risk factors for the comorbidity. RESULTS: The prevalence of comorbidity of osteoporosis/osteopenia and kidney stones was 4.82%. Femoral neck BMD T-score was negatively associated with the prevalence of kidney stones (n=11,864). Dietary magnesium intake, serum phosphorus, and bicarbonate were negatively associated with the comorbidity prevalence, and serum ALP was positively associated with the comorbidity prevalence (n=6978). Additionally, there remain significant associations of dietary magnesium intake, serum ALP, and bicarbonate with not only femoral neck BMD T-score (n=11331), but also the prevalence of kidney stones (n=23,111) in general population. Furthermore, dietary magnesium intake was positively correlated to femoral neck BMD T-score in stone formers (SFs), while serum ALP was negatively correlated to femoral neck BMD T-score in SFs (n=1163). CONCLUSION: Low femoral neck BMD was closely associated with an increased risk of kidney stones. Low magnesium intake and increased serum ALP were associated with the increased risk of the comorbidity, as well as indicative of low femoral neck BMD T-score in SFs, which offered a clue to further clarify the mechanism leading to paradoxical calcification of bone resorption and kidney stones, and had the potential to perform personalized diagnostic workup for low BMD in SFs.

The prevalence of vitamin D deficiency and the factors affecting vitamin D levels in children admitted to the outpatient clinic of pediatric endocrinology in Bolu Province.

BACKGROUND: The present study aimed to determine the rate of vitamin D deficiency in children who presented to the pediatric endocrinology outpatient clinic in Bolu and to investigate the factors affecting vitamin D levels. METHODS: Vitamin D levels of 1008 children and adolescents were retrospectively analyzed according to age group (0-1, 1-10, and 10-18 years), gender, season, month, obesity and other diseases, and deficiency category. Moreover, calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels were evaluated. Comparisons and correlation analyses between related groups were performed. RESULTS: The mean vitamin D level of the patients was 16.35±9.56 ng/mL and was lower in girls (14.90±9.56 ng/mL) than in boys (18.68±9.63 ng/mL, p<0.001). Overall, 18.3% of the children and adolescents had vitamin D insufficiency, 52.3% had vitamin D deficiency, and 3.5% had severe vitamin D deficiency. Vitamin D levels were lower in 10-18-year age group than in the other age groups (p<0.001), and levels were higher in summer and autumn than in winter and spring (p<0.001). Vitamin D levels of participants with obesity (14.3 ± 8.3 ng/mL) were significantly lower than normal-weight participants with no health problems (15.9 ± 8.3 ng/mL, p = 0.004). There was a negative correlation between vitamin D, alkaline phosphatase, and parathyroid hormone levels in the 1-10-year age group, but a positive correlation between vitamin D, alkaline phosphatase, and calcium levels in the 10-18-year age group. CONCLUSION: The rate of vitamin D deficiency is high among children and adolescents who presented to the endocrine outpatient clinic in Bolu. The season appears to be an important factor affecting vitamin D levels as well as the relationship between vitamin D and parathyroid hormone. Obese children and adolescents living in this region may be advised to take vitamin D supplements in winter and spring.

Transcriptional responses of the marine diatom Chaetoceros tenuissimus to phosphate deficiency.

The planktonic diatom Chaetoceros tenuissimus sometimes forms blooms in coastal surface waters where dissolved inorganic phosphorus (P) is typically deficient. To understand the molecular mechanisms for survival under P-deficient conditions, we compared whole transcripts and metabolites with P-sufficient conditions using stationary growth cells. Under P-deficient conditions, cell numbers and photosynthetic activities decreased as cells entered the stationary growth phase, with downregulation of transcripts related to the Calvin cycle and glycolysis/gluconeogenesis. Therefore, metabolites varied across nutritional conditions. Alkaline phosphatase, phosphodiesterase, phytase, phosphate transporter, and transcription factor genes were drastically upregulated under dissolved inorganic P deficiency. Genes related to phospholipid degradation and nonphospholipid synthesis were also upregulated. These results indicate that C. tenuissimus rearranges its membrane composition from phospholipids to nonphospholipids to conserve phosphate. To endure in P-deficient conditions, C. tenuissimus modifies its gene responses, suggesting a potential survival strategy in nature.

Phosphorus storage and utilization strategies of two bloom-forming freshwater cyanobacteria.

The inter-relationships between cellular phosphorus (P) storage, dissolved inorganic P (DIP) uptake affinity, alkaline phosphatase activity (APA) and dissolved inorganic nitrogen (DIN) concentrations were studied in two ubiquitous diazotrophic freshwater cyanobacteria, Raphidiopsis raciborskii (six strains) and Chrysosporum ovalisporum (two strains). DIP uptake kinetics were measured using rates of incorporation of the radio-isotope, 33P and APA as a proxy for DOP-ester utilization. The study showed that DIP uptake of individual strains followed Michaelis-Menten kinetics (modified in our study to incorporate cellular P quotas), but differed with DIN and P availability, and between growth stages. High-affinity DIP uptake and APA were activated below a P quota threshold of approximately 0.01 µg P µg-1 C across the species and strains. C. ovalisporum had significantly higher APA and P quotas (per unit C and cell) but lower uptake affinity than R. raciborskii. Demand for DIP by C. ovalisporum increased when N fixation occurred, but typically not for R. raciborskii. Our results indicate that cyanobacterial species and strains differ in their strategies to P limiting conditions, and highlight the interplay between N and P. Physiological adaptations like APA and diazotrophy of cyanobacteria adapting to low DIP and/or DIN conditions may occur simultaneously and drive species dominance in oligotrophic environments.

Prevalence of elevated alkaline phosphatase levels among post-bariatric surgery patients.

INTRODUCTION: Little is known about the prevalence of elevated alkaline phosphatase in post-bariatric surgery patients due to under-utilization of this test after surgery. Elevated alkaline phosphatase levels are caused by hepatobiliary disease or bone resorption, which can lead to gallstones and osteoporosis. Early, post-operative measurement of alkaline phosphatase can prevent complications, thus reducing morbidity and overall healthcare costs. The purpose of this study was to determine the prevalence of elevated alkaline phosphatase levels among post-operative bariatric surgery patients. METHODS: This was a retrospective study of patients 18 years or older, who underwent laparoscopic sleeve gastrectomy (LSG) at a Midwestern Weight Management Clinic between January 1, 2002 and December 31, 2020. Alkaline phosphatase levels, weight, body mass index (BMI), gamma-glutamyl transferase (GGT), parathyroid hormone (PTH), calcitriol, and calcitonin, vitamin D and multivitamin supplementation were measured at baseline, 3, 6, and 12 months post-surgery. RESULTS: Two hundred thirty patients with mean age of 47 years and BMI of 44.6 were included with 80.9% (n = 186) female. Alkaline phosphatase was elevated relative to baseline for 36.1% of patients (n = 52) at 3 months post-surgery, 42.4% of patients (n = 56) at 6 months, and 43.3% of patients (n = 45) at 12 months (p < 0.001). There were six cases of documented cholelithiasis post-surgery. CONCLUSION: A significant proportion of participants experienced elevations in alkaline phosphatase following surgery, indicating that the prevalence of gallbladder pathology and bone resorption may be higher than previously thought. This merits additional investigation into these complications post-operatively to determine prevalence and avoid excess morbidity.