PubMed · 805842
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K G Bhansali. 1975. Placental function tests by blood analysis.. https://pubmed.ncbi.nlm.nih.gov/805842/
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Marine picocyanobacteria of the genera Prochlorococcus and Synechococcus, the two most abundant phototrophs on Earth, thrive in oligotrophic oceanic regions. While it is well known that specific lineages are exquisitely adapted to prevailing in situ light and temperature regimes, much less is known of the molecular machinery required to facilitate occupancy of these low-nutrient environments. Here, we describe a hitherto unknown alkaline phosphatase, Psip1, that has a substantially higher affinity for phosphomonoesters than other well-known phosphatases like PhoA, PhoX, or PhoD and is restricted to clade III Synechococcus and a subset of high light I-adapted Prochlorococcus strains, suggesting niche specificity. We demonstrate that Psip1 has undergone convergent evolution with PhoX, requiring both iron and calcium for activity and likely possessing identical key residues around the active site, despite generally very low sequence homology. Interrogation of metagenomes and transcriptomes from TARA oceans and an Atlantic Meridional transect shows that psip1 is abundant and highly expressed in picocyanobacterial populations from the Mediterranean Sea and north Atlantic gyre, regions well recognized to be phosphorus (P)-deplete. Together, this identifies psip1 as an important oligotrophy-specific gene for P recycling in these organisms. Furthermore, psip1 is not restricted to picocyanobacteria and is abundant and highly transcribed in some α-proteobacteria and eukaryotic algae, suggesting that such a high-affinity phosphatase is important across the microbial taxonomic world to occupy low-P environments.
The effect of human interleukin-4 (hIL-4) on mineralization in human osteoblast-like cells was investigated. Confluent cells were incubated with hIL-4 for 16 or 30 days in the presence or absence, respectively, of alpha-glycerophosphate (alpha-GP), which accelerates the mineralization process. hIL-4 (0.3 ng/ml) induced mineralization with 1.9-, 26- and 37-fold increases of hydroxyproline, calcium, and osteocalcin content, respectively, in the presence of alpha-GP. Mineralization was not induced with other cytokines, hIL-1, hIL-2, hIL-6, or mIL-4. hIL-4 also induced mineralization in the absence of alpha-GP in a manner different from that of 1 alpha, 25(OH)2 vitaminD3 (1,25(OH)2VD3). These findings suggest that IL-4 may play an important role in bone formation.
In a previous study [Shaw, C., Pasqualotto, B. and Lanius, R.A., Mol. Neuropharmacol., in press] we have shown that phosphorylation and dephosphorylation actions of protein kinase and alkaline phosphatase lead to decreases or increases in the number of GABAA and AMPA receptors in adult rat neocortex. Using the same in vitro cortical slice preparation, we have now examined the role of these enzymes in regulating GABAA and AMPA receptors at different stages of postnatal development. GABAA receptors were labelled with [3H]SR95531 [Shaw, C. and Scarth, B.A., Mol. Brain Res., 11 (1991) 273-282]; AMPA receptors were labelled with [3H]CNQX [Lanius, R.A. and Shaw, C., Mol. Brain Res., 15 (1992) 256-262]. At postnatal day 14, GABAA receptors showed a decrease in binding in response to alkaline phosphatase treatment as opposed to an increase in binding observed in response to protein kinase treatment. Similar effects were observed for AMPA receptors at 20 days of age. The direction of regulation following the enzyme treatments were opposite to those observed in the adult cortex for both receptor populations. These fundamental changes in the enzymatic nature of regulation for such key inhibitory and excitatory receptor populations in cortex may signal an important role for age-dependent kinases and phosphatases in the events leading to modifications in neuronal function during postnatal development.