Acid Phosphatase Activity in Freshwater Ecosystems of Western Cuba and its Relationship with Water Quality

Enzyme activity plays an important role in the functioning of aquatic ecosystems. It is sensitive to changes in environmental conditions such as pH, temperature, and nutrient concentration. The objective of this work was to determine the acid phosphatase activity (AcPA) in the Almendares and San Juan rivers (western Cuba) and its relationship with physicochemical and microbiological indicators. For this purpose, AcPA, temperature, pH, total dissolved solids, electrical conductivity, dissolved oxygen, concentration of nitrates, nitrites, ammonium, phosphates, total heterotrophs, enterococci, Escherichia coli, thermotolerant coliforms, chlorophyll a and chemical oxygen demand (COD) were determined at three sampling stations on the Almendares River and at three sampling stations on the San Juan River. In addition, the nutrient pollution index (NPI) and the N:P ratio were calculated. In both ecosystems, spatio-temporal variability was observed in the enzymatic activity. In the Almendares River (polluted ecosystem), AcPA was positively correlated with nitrate concentration and COD. While in the San Juan River (slightly contaminated ecosystem) the AcPA correlated negatively with the pH and NPI and positively with the concentrations of total heterotrophs, Escherichia coli, chlorophyll a and the N:P ratio. These results show the impact of anthropogenic pollution on AcPA in freshwater ecosystems with a tropical climate.

Isolation and characterization of phosphate solubilizing bacteria in saline soil from Costal Region of Odisha

The present study was conducted to isolate phosphate solubilizing bacteria (PSB) from rhizospheric saline soils of coastal Odisha, India and evaluated their phosphate solubilizing ability. Total four PSB were isolated based on the halo zone formation (solubilizing index 2.63-3.14) on PVK agar medium and were characterized based on biochemical and molecular characteristics as Bacillus subtilis (B1), B. megaterium (B2), Sphingomonas paucimobilis (P2) and Kocuria kristinae (P6). The inorganic phosphate released by PSB ranged from 18.532 to 38.250µg/ml with decreasing the pH PVK broth up to 3.9. Acid phosphatase activity for PSB were recorded 84.237-98.658µmol/min. Glucose was found to be the best carbon source for B. subtilis, Sphingomonas paucimobilis and Kocuria kristinae whereas mannitol for B. megaterium. Optimum acid phosphatase activity was observed for all the four PSB isolates in presence of ammonium sulphate as nitrogen source in PVK broth at 30oC and pH 7.0.

Recessive Mutations in ACP4 Cause Amelogenesis Imperfecta

Amelogenesis imperfecta (AI) is an innate disorder that affects the formation and mineralization of the tooth enamel. When diagnosed with AI, one’s teeth can be hypoplastic (thin enamel), hypomature (normal enamel thickness but discolored and softer than normal enamel), hypocalcified (normal enamel thickness but extremely weak), or mixed conditions of the above. Numerous studies have revealed the genes that are involved in causing AI. Recently, ACP4 (acid phosphatase 4) was newly found as a gene causing hypoplastic AI, and it was suggested that mutant forms of ACP4 might affect access to the catalytic core or the ability to form a homodimer. In this study, a Korean and a Turkish family with hypoplastic AI were recruited, and their exome sequences were analyzed. Biallelic mutations were revealed in ACP4: paternal (NM_033068: c.419C>T, p.(Pro140Leu)) and maternal (c.262C>A, p.(Arg88Ser)) mutations in family 1 and a paternal (c.713C>T, p.(Ser238Leu)) mutation and de novo (c.350A>G, p.(Gln117Arg)) mutation in the maternal allele in family 2. Mutations were analyzed by cloning, mutagenesis, immunofluorescence, immunoprecipitation, and acid phosphatase activity test. Comparison between the wild-type and mutant ACP4s showed a decreased amount of protein expression from the mutant forms, a decreased ability to form a homodimer, and a decreased acid phosphatase activity level. We believe that these findings will not only expand the mutational spectrum of ACP4 but also increase our understanding of the mechanism of ACP4 function during normal and pathologic amelogenesis.