Effects of dietary proteins on iron bioavailability—A review

In this review we have summarized the iron bioavailability literature dealing with protein (or major dietary protein source) effects and proposed a mechanism for these effects compatible with existing empirical data. Data from studies employing a variety of approaches are fairly consistent in showing that meats enhance non-heme iron absorption while plant, milk and egg proteins depress it. The variable, and sometimes opposite, effects of different proteins on iron bioavailability may be explained by the following proposed mechanism: (1) protein enhances iron bioavailability by releasing peptides during digestion which form soluble, low molecular weight complexes that readily release iron to mucosal receptors; (2) protein depresses iron bioavailability by releasing peptides which form insoluble complexes with iron or which form soluble complexes that do not release iron to mucosal receptors. Data from the literature, including our own evidence, which support the above hypothesis are discussed.     

Groundwater-surface water interactions and agricultural nutrient transport in a Great Lakes clay plain system

Nutrient export from agricultural land to surface waters is a significant environmental concern within the Great Lakes Basin (GLB). A field-based watershed-scale study was completed to investigate spatial and temporal variations of phosphorus and nitrate to assess nutrient transport pathways and groundwater-surface water interactions in an agriculturally dominated clay plain system. This was conducted in the 127 km² Upper Parkhill Watershed, near Lake Huron in southwestern Ontario, Canada. Data collection occurred from June 2018 to May 2019 via continuous sensor deployment and discrete sampling of stream water, groundwater, hyporheic zone, and tile drainage water. Samples were analyzed for various nutrient species (total, total dissolved, soluble reactive, and particulate phosphorus, and nitrate-N) to examine the hydrological dynamics of principal transport pathways of agriculturally-derived nutrients. Total phosphorus and nitrate concentrations in stream water ranged from 0.007 to 0.324 mg/L and 0.32 to 13.13 mg NO₃^?-N/L, respectively. Tile drainage water total phosphorous concentrations varied from 0.006 to 0.066 mg/L. Groundwater total dissolved phosphorus concentrations ranged from <0.003 to 0.085 mg/L. Transport of phosphorus through tile drainage was observed to be greater than through groundwater over the study period. No distinct relationship was observed between nutrient concentrations in the hyporheic zone and the vertical hydraulic gradient within this zone in the studied stream reach. Preliminary correlations were discerned between water quality observations and recognized land management practices. Given the elevated stream nutrient concentrations, these results are consequential for the continual improvement of strategies and programs devised to conserve water resources within the GLB.     

Towards improving an Area of Concern: Main-channel habitat rehabilitation priorities for the Maumee River

The Maumee River watershed in the Laurentian Great Lakes Basin has been impacted by decades of pollution and habitat modification due to human settlement and development. As such, the lower 35 km of the Maumee River and several smaller adjacent watersheds comprising over 2000 km² were designated the Maumee Area of Concern (AOC) under the revised Great Lakes Water Quality Agreement in 1987. As part of pre-rehabilitation assessments in the Maumee AOC, we assessed fish and invertebrate communities in river km 24–11 of the Maumee River to identify: 1) areas that exhibit the highest biodiversity, 2) habitat characteristics associated with high biodiversity areas, 3) areas in need of protection from further degradation, and 4) areas that could feasibly be rehabilitated to increase biodiversity. Based on benthic trawl data, shallow water habitats surrounding large island complexes had the highest fish diversity and catch per unit effort (CPUE). Electrofishing displayed similar fish diversity and CPUE patterns across habitat types early in the study but yielded no discernable fish diversity or CPUE patterns towards the end of our study. Although highly variable among study sites, macroinvertebrate density was greatest in shallow water habitats <2.5 m and around large island complexes. Our results provide valuable baseline data that could act as a foundation for developing rehabilitation strategies in the lower Maumee River and for assessing the effectiveness of future aquatic habitat rehabilitation projects. In addition to increasing in-channel habitat, watershed-scale improvements of water quality might be necessary to ensure rehabilitation strategies are successful.     

A standards-based interoperable single sign-on framework in ARC Grid middleware

Security infrastructure is one of the most challenging tasks in the development, integration and deployment of Grid middlewares. Even though the Grid community addresses the security issue through public key infrastructures (PKI) to support mutual authentication using X.509 certificates, maintaining X.509 credentials is not that easy for non-IT-experts, and has proved to be an obstacle for a more wide deployment of Grid technologies. The identity federation is an increasingly popular technology that can facilitate cross-domain single sign-on without requiring the users to maintain any credentials additional to their own institutional accounts. We believe that utilizing identity federation for Grid middlewares is a promising path for the Grid technology to get more widely used. This paper describes a single sign-on infrastructure developed as a part of the NorduGrid ARC (Advanced Resource Connector) Grid middleware. It adopts the identity federation standard (SAML), as well as other Web Service standards. It focuses on a single sign-on solution at the middleware level for users to access Grids by only using their frequently used accounts, without being bothered to maintain X.509 credentials. Users can use their username/password only to access Grids developed in ARC middleware, as well as access Grids developed in other middlewares that requires users to provide X.509 certificates. Moreover, the single sign-on for workflow-like Grid applications (in which intermediate entities act on behalf of users) is also supported. As an important aspect of single sign-on, authorization is also considered by implementing an attribute-based authorization using SAML standard. In addition, the performance of single sign-on solution is measured. We identify performance limitations of security-related services inside this solution, and analyse the ways to avoid the limitations. To our knowledge, the work presented in this paper is the first evaluated implementation that utilizes identity federation for Grid usage on the middleware level.     

Characterization of wet microalgal cells pretreated with steam for lipid extraction

Steam pretreatment was employed to disrupt microalgal cells for lipids extraction.Effects of steam pre-treatment on microstructure of microalgal cells were investigated through scanning electron microscopy(SEM) and transmission electron microscopy (TEM).Effect of treatment on lipid extraction was also stud-ied.Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macro-molecules contained in cell wall.Maximum curvature was increased from 1.88 × 10-6 m-1 to 1.43 × 10-7 m-1 after treatment with the steam at 130 ℃.The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min,and further increased to 1.47 when the pre-treatment time was increased to 60 min.Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules,and finally destroyed microalgal cell walls at pretreatment temperature of 130 ℃ and pretreatment time of 60 min.Lipid extracted from wet microalgal was signif-icantly increased (2.1-fold) after pretreatment.     

Plasma Membrane H+-ATPase SmPHA4 Negatively Regulates the Biosynthesis of Tanshinones in Salvia miltiorrhiza

Salvia miltiorrhiza Bunge has been widely used in the treatment of cardiovascular and cerebrovascular diseases, due to the pharmacological action of its active components such as the tanshinones. Plasma membrane (PM) H⁺-ATPase plays key roles in numerous physiological processes in plants. However, little is known about the PM H⁺-ATPase gene family in S. miltiorrhiza (Sm). Here, nine PM H⁺-ATPase isoforms were identified and named SmPHA1–SmPHA9. Phylogenetic tree analysis showed that the genetic distance of SmPHAs was relatively far in the S. miltiorrhiza PM H⁺-ATPase family. Moreover, the transmembrane structures were rich in SmPHA protein. In addition, SmPHA4 was found to be highly expressed in roots and flowers. HPLC revealed that accumulation of dihydrotanshinone (DT), cryptotanshinone (CT), and tanshinone I (TI) was significantly reduced in the SmPHA4-OE lines but was increased in the SmPHA4-RNAi lines, ranging from 2.54 to 3.52, 3.77 to 6.33, and 0.35 to 0.74 mg/g, respectively, suggesting that SmPHA4 is a candidate regulator of tanshinone metabolites. Moreover, qRT-PCR confirmed that the expression of tanshinone biosynthetic-related key enzymes was also upregulated in the SmPHA4-RNAi lines. In summary, this study highlighted PM H⁺-ATPase function and provided new insights into regulatory candidate genes for modulating secondary metabolism biosynthesis in S. miltiorrhiza.     

Ubiquitin-Specific Protease 29 Regulates Cdc25A-Mediated Tumorigenesis

Cell division cycle 25A (Cdc25A) is a dual-specificity phosphatase that is overexpressed in several cancer cells and promotes tumorigenesis. In normal cells, Cdc25A expression is regulated tightly, but the changes in expression patterns in cancer cells that lead to tumorigenesis are unknown. In this study, we showed that ubiquitin-specific protease 29 (USP29) stabilized Cdc25A protein expression in cancer cell lines by protecting it from ubiquitin-mediated proteasomal degradation. The presence of USP29 effectively blocked polyubiquitination of Cdc25A and extended its half-life. CRISPR-Cas9-mediated knockdown of USP29 in HeLa cells resulted in cell cycle arrest at the G0/G1 phase. We also showed that USP29 knockdown hampered Cdc25A-mediated cell proliferation, migration, and invasion of cancer cells in vitro. Moreover, NSG nude mice transplanted with USP29-depleted cells significantly reduced the size of the tumors, whereas the reconstitution of Cdc25A in USP29-depleted cells significantly increased the tumor size. Altogether, our results implied that USP29 promoted cell cycle progression and oncogenic transformation by regulating protein turnover of Cdc25A.