Identification of two novel bacterial phosphatase-encoding genes in Pseudomonas putida strain P13.

AIMS: Isolation and identification of genes encoding putative phosphatases from Pseudomonas putida strain P13 DSM 23335. METHODS AND RESULTS: By functional screening of a P. putida P13 genomic library, a number of Pho+ clones were identified. Two genes were identified that encoded proteins exhibiting both phytase and sugar phosphatase activities. The proteins were 249 and 462 amino acids, with molecular masses of 26 and 50 kDa respectively. Sequence alignments revealed no significant similarities to representatives of known phosphatase or phytase gene families. However, the genes were found to have a high similarity to members of the major facilitator superfamily (MFS). Both genes were overexpressed in Escherichia coli and the corresponding partially purified recombinant enzymes were found to have significant phytate-dephosphorylating activity. The protein designated P. putida phytase 1 (Ppp1) displayed the highest activity among potential substrates studied on Na phytate, whereas Ppp2 more likely represents a sugar phosphatase than a phytase. The optimal conditions for phytate dephosphorylation were determined as 60°C and pH 4·5 (Ppp1) or pH 5·0 (Ppp2). CONCLUSIONS: Two novel bacterial phosphatase-encoding genes, named ppp1 and ppp2, were isolated from P. putida P13 DSM 23335 by a functional screening procedure. SIGNIFICANCE AND IMPACT OF THE STUDY: Phosphatase-encoding genes are of great importance for industrial applications, particularly in agriculture. The identified phosphatase genes represent a new class of acid phosphatases.

Profile of human leukocyte antigen class I alleles in patients with dengue infection from Western India.

Human leukocyte antigen (HLA) class I alleles are known to affect the cytotoxic T lymphocyte responses and influence susceptibility to viral infections. The objective of the present study was to find out whether HLA class I alleles are associated with clinical manifestations of dengue virus infection. The profile of HLA class I alleles were investigated in 224 human subjects [85 dengue fever (DF) cases, 29 dengue hemorrhagic fever (DHF) cases and 110 healthy controls (HCs)] from Western India using PCR based methods. Results revealed significantly higher frequency of HLA-A(∗)33 in DF cases compared to HCs [P = 0.032, Odds ratio (OR) 2.12]. The frequency of HLA-A(∗)02:11 was higher in DHF cases compared to DF cases. The frequency of HLA-B(∗)18 was significantly higher in dengue (DEN) cases [P = 0.047 Pc = 0.846, OR 3.53]. The frequency of HLA-Cw(∗)07 allele was significantly higher in DEN cases [DEN vs. HCs: P = 0.0120, Pc = 0.168, OR 2.00]. Significance was observed even when the cases were categorized in to DF and DHF [DF vs. HCs: P = 0.0349, Pc = 0.49, OR 1.87; DHF vs. HCs: P = 0.0399, Pc = 0.56, OR 2.4]. The combined frequency of HLA-Cw(∗)07 with HLA-DRB1(∗)07/(∗)15 genotype was significantly higher in DHF cases as compared to DF and HCs [DHF vs. HCs: P = 0.022, OR 5.31; DHF vs. DF: P = 0.027, OR 5.49]. On the other hand, the frequency of combination of HLA-Cw(∗)07 without HLA-DRB1(∗)07 was significantly higher in DF cases compared to HCs [DF vs. HCs: P = 0.002, OR 2.42 (1.28-4.55)]. The results suggest that HLA-A(∗∗)33 may be associated with DF while HLA-B(∗)18 and HLA-Cw(∗)07 alleles may be associated with symptomatic dengue requiring hospitalization. In the presence of HLA-DRB1(∗)07/(∗)15 genotype, HLA-Cw(∗)07 is associated with increased risk of developing DHF while in the presence of other HLA-DRB1 alleles, HLA-Cw(∗)07 is associated with DF.