Screening and distributing features of bacteria with hydantoinase and carbamoylase

Groundwater quality and hydrochemical characteristics in the upper Seybouse sub-basin, Northeast Algeria

The present study aims to evaluate the groundwater quality in an area characterized by significant human anthropic activities within the upper Seybouse. In order to assess the quality, a total of 20 samples were analyzed to identify the chemical and bacteriological composition of the water, its variations, and their potential impacts on the environment and human health. The results revealed concentrations of the chemical and bacteriological elements exceeding the WHO standards, with high levels of electrical conductivity (EC) (peak = 4210 μS/cm), Ca2+ (peak = 340.68 mg/L), Na+ (peak = 360 mg/L), HCO3- (peak = 287 mg/L), Cl- (peak = 542 mg/L), SO42- (peak = 687 mg/L), NO3- (pek = 65.91 mg/L), fecal coliforms (FC) (peak = 160 UFC/mL), fecal Streptococcus (FS) (peak = 43 UFC/mL), and Clostridium perfringens (CP) (peak = 29 UFC/mL). Within the basin, two different facies have been identified: Cl-SO4-Na type and Cl-SO4-Ca type. The calculated Water Quality Index (WQI) indicates that none of the groundwater samples are suitable for drinking or human consumption. The detection of pathogenic microorganisms through diverse molecular methods has revealed the existence of eight distinct species, encompassing pathogenic strains that can affect human health. Moreover, the dissolution of geologic formations can influence the water's chemistry. In this region, groundwater pollution seems to be influenced by anthropogenic and agricultural factors such as fertilizer application, irrigation practices, and the release of domestic sewage.

Kaguacidine A: a novel spirohydantoin-containing cucurbitane glycoside from vines of Momordica charantia L

The spirohydantoin-containing cucurbitane-type triterpenoid, kaguacidine A (1), was isolated and purified from 95% ethanol extract of vines of Momordica charantia L. (Cucurbitaceae). Its unprecedented chemical structure, a spirohydantoin substituent at C-23 of cucurbitane, was elucidated by extensive spectroscopic analyses, including HRESIMS, IR, optical rotation, 1 D- and 2 D-NMR spectra. The possible biosynthetic pathway is deduced and may be attributed to the metabolic activity of microbial symbionts in M. charantia L. Compound 1 was evaluated for anti-inflammatory activity against LPS-induced NO production in RAW 264.7 cells and anti-proliferative activity against four cancer cell lines, including HEp-2, MCF-7, Hep-G2, and WiDr. Compound 1 showed moderate anti-inflammatory activity with an IC50 value of 18.5 ± 0.4 μg/mL and weak anti-proliferative activity against MCF-7, HEp-2, Hep-G2, and WiDr with IC50 values of >40, 33.8 ± 0.6, 31.0 ± 0.7, and 27.0 ± 0.7 μM, respectively.

Characterization of divergent promoters PmaiA and Phyd from Gordonia: Co-expression and regulation by CRP

Divergent promoters are often responsible for controlling gene expression of related genes of the same pathway or for coordinating regulation at different time points. There are relatively few reports on characterization of divergent promoters in bacteria. In the present study, microarray profiling was carried out to analyze gene expression during growth of Gordonia sp. IITR100, which led to the identification of 35 % of adjacent gene candidates that are divergently transcribed. We focus here on the in-depth characterization of one such pair of genes. Two divergent promoters, PmaiA and Phyd, drive the expression of genes encoding maleate cis-trans isomerase (maiA) and hydantoinase (hyd), respectively. Our findings reveal asymmetric promoter activity with higher activity in the reverse orientation (Phyd) as compared to the forward orientation (PmaiA). Minimal promoter region for each orientation was identified by deletion mapping. Deletion of a 5'-untranslated region of each gene resulted in an increase in promoter activity. A putative binding site for CRP (Catabolite Repressor Protein) transcription regulator was also identified in the 80 bp common regulatory region between the -35 hexamers of the two promoters. The results of this study suggest that CRP-mediated repression of PmaiA occurs only in the cells grown in glucose. Phyd, on the other hand, is not repressed by CRP. However, deletion of the CRP binding site located between -95 to -110 upstream to the transcription start site of the maiA gene resulted in increased activity of PmaiA and decreased activity of Phyd. A single CRP binding site, therefore, affects the two promoters differently.

Metagenomics Analysis Reveals an Extraordinary Inner Bacterial Diversity in Anisakids (Nematoda: Anisakidae) L3 Larvae

L3 larvae of anisakid nematodes are an important problem for the fisheries industry and pose a potential risk for human health by acting as infectious agents causing allergies and as potential vectors of pathogens and microrganisms. In spite of the close bacteria-nematode relationship very little is known of the anisakids microbiota. Fresh fish could be contaminated by bacteria vectored in the cuticle or in the intestine of anisakids when the L3 larvae migrate through the muscles. As a consequence, the bacterial inoculum will be spread, with potential effects on the quality of the fish, and possible clinical effects cannot be discarded. A total of 2,689,113 16S rRNA gene sequences from a total of 113 L3 individuals obtained from fish captured along the FAO 27 fishing area were studied. Bacteria were taxonomically characterized through 1803 representative operational taxonomic units (OTUs) sequences. Fourteen phyla, 31 classes, 52 orders, 129 families and 187 genera were unambiguously identified. We have found as part of microbiome an average of 123 OTUs per L3 individual. Diversity indices (Shannon and Simpson) indicate an extraordinary diversity of bacteria at an OTU level. There are clusters of anisakids individuals (samples) defined by the associated bacteria which, however, are not significantly related to fish hosts or anisakid taxa. This suggests that association or relationship among bacteria in anisakids, exists without the influence of fishes or nematodes. The lack of relationships with hosts of anisakids taxa has to be expressed by the association among bacterial OTUs or other taxonomical levels which range from OTUs to the phylum level. There are significant biological structural associations of microbiota in anisakid nematodes which manifest in clusters of bacteria ranging from phylum to genus level, which could also be an indicator of fish contamination or the geographic zone of fish capture. Actinobacteria, Aquificae, Firmicutes, and Proteobacteria are the phyla whose abundance value discriminate for defining such structures.

Characterization of a thermotolerant and acidophilic mannanase producing Microbacterium sp. CIAB417 for mannooligosachharide production from agro-residues and dye decolorization

Mannanases are ubiquitous enzymes and are being explored for diverse industrial applications. In this study, a novel bacterial strain Microbacterium sp. CIAB417 was identified and characterized for extracellular production of mannanase. Microbacterium sp. CIAB417 was found to produce maximum mannanase after 36 h of incubation at 37 °C. Mannanase produced by the isolate was observed for maximum activity at optimum pH of 6 and optimum temperature of 50 °C. Crude mannanase was found to be capable of producing mannooligosachharides (MOS) by hydrolyzing hemicellulose from locust bean gum and Aloe vera. The produced MOS was characterized and found to be mixture of mannobiose to mannohexose units. Mannanase was also explored for decolorization of dyes. Bromophenol blue and coomassie blue R-250 were observed to be decolorized to the extent of 45.40 and 42.75%, respectively. Hence, the identified bacterial strain producing mannanase could be of great significance for applications in food and textile industry.

Efficient Synthesis of Purine Nucleoside Analogs by a New Trimeric Purine Nucleoside Phosphorylase from Aneurinibacillus migulanus AM007

Purine nucleoside phosphorylases (PNPs) are promising biocatalysts for the synthesis of purine nucleoside analogs. Although a number of PNPs have been reported, the development of highly efficient enzymes for industrial applications is still in high demand. Herein, a new trimeric purine nucleoside phosphorylase (AmPNP) from Aneurinibacillus migulanus AM007 was cloned and heterologously expressed in Escherichia coli BL21(DE3). The AmPNP showed good thermostability and a broad range of pH stability. The enzyme was thermostable below 55 °C for 12 h (retaining nearly 100% of its initial activity), and retained nearly 100% of the initial activity in alkaline buffer systems (pH 7.0–9.0) at 60 °C for 2 h. Then, a one-pot, two-enzyme mode of transglycosylation reaction was successfully constructed by combining pyrimidine nucleoside phosphorylase (BbPyNP) derived from Brevibacillus borstelensis LK01 and AmPNP for the production of purine nucleoside analogs. Conversions of 2,6-diaminopurine ribonucleoside (1), 2-amino-6-chloropurine ribonucleoside (2), and 6-thioguanine ribonucleoside (3) synthesized still reached >90% on the higher concentrations of substrates (pentofuranosyl donor: purine base; 20:10 mM) with a low enzyme ratio of BbPyNP: AmPNP (2:20 μg/mL). Thus, the new trimeric AmPNP is a promising biocatalyst for industrial production of purine nucleoside analogs.

Molecular Detection of Diverse Leifsonia Strains Associated With Sugarcane

Leifsonia xyli subsp. xyli, causal agent of ratoon stunting disease (RSD) of sugarcane (Saccharum interspecific hybrids), is the most well-known member of the Microbacteriaceae genus Leifsonia. However, the presence of other Leifsonia strains associated with sugarcane has not been reported. A total of 697 Australian and 40 Indonesian sugarcane fields were screened by leaf sheath biopsy (LSB) PCR using primers specific for L. xyli subsp. xyli, in addition to primers designed to amplify DNA from other members of the genus Leifsonia. While L. xyli subsp. xyli was detected in 126 fields, a total of 37 distinct and novel Leifsonia and non-Leifsonia strains were detected in 116 fields. Representatives of these strains were also detected in multiple samples of expressed xylem sap. Sequencing and phylogenetic analyses demonstrated the presence of a broad complex of novel Leifsonia strains, in addition to strains closely related to the recently erected Cnuibacter genus. Attempts to isolate Leifsonia strains were unsuccessful; however, one strain related to Cnuibacter was recovered from expressed xylem sap. Among the genetically diverse lineages discovered, identical genotypes were present in multiple sugarcane varieties growing in disparate regions in different years, strongly suggesting an ongoing association with sugarcane. The epidemiological significance of these strains is unknown, but there is evidence that they can interfere with serological and microscopic RSD diagnostics, and there is the potential that they may represent new and distinct pathologies of sugarcane.

In vivo immobilization of D-hydantoinase in Escherichia coli

D-P-Hydroxyphenylglycine (D-HPG) is a precursor required for the synthesis of semi-synthetic antibiotics. This unnatural amino acid can be produced by a transformation reaction mediated by D-hydantoinase (D-HDT) and d-amidohydrolase. In this study, a method was developed to integrate production and immobilization of recombinant D-HDT in vivo. This was approached by first fusion of the gene encoding D-HDT with phaP (encoding phasin) of Ralstonia eutropha H16. The fusion gene was then expressed in the Escherichia coli strain that carried a heterologous synthetic pathway for polyhydroxyalkanoate (PHA). As a result, d-HDT was found to associate with isolated PHA granules. Further characterization illustrated that D-HDT immobilized on PHA exhibited the maximum activity at pH 9 and 60°C and had a half-life of 95 h at 40°C. Moreover, PHA-bound d-HDT could be reused for 8 times with the conversion yield exceeding 90%. Overall, it illustrates the feasibility of this approach to facilitate in vivo immobilization of enzymes in heterologous E. coli strain, which may open a new avenue of enzyme application in industry.

Microdiversity of deep-sea Bacillales isolated from Tyrrhenian sea sediments as revealed by ARISA, 16S rRNA gene sequencing and BOX-PCR fingerprinting

With respect to their terrestrial relatives, marine Bacillales have not been sufficiently investigated. In this report, the diversity of deep-sea Bacillales, isolated from seamount and non-seamount stations at 3,425 to 3,580 m depth in the Tyrrhenian Sea, was investigated using PCR fingerprinting and 16S rRNA sequence analysis. The isolate collection (n=120) was de-replicated by automated ribosomal intergenic spacer analysis (ARISA), and phylogenetic diversity was analyzed by 16S rRNA gene sequencing of representatives of each ARISA haplotype (n=37). Phylogenetic analysis of isolates showed their affiliation to six different genera of low G+C% content Gram-positive Bacillales: Bacillus, Staphylococcus, Exiguobacterium, Paenibacillus, Lysinibacillus and Terribacillus. Bacillus was the dominant genus represented by the species B. licheniformis, B. pumilus, B. subtilis, B. amyloliquefaciens and B. firmus, typically isolated from marine sediments. The most abundant species in the collection was B. licheniformis (n=85), which showed seven distinct ARISA haplotypes with haplotype H8 being the most dominant since it was identified by 63 isolates. The application of BOX-PCR fingerprinting to the B. licheniformis sub-collection allowed their separation into five distinct BOX genotypes, suggesting a high level of intraspecies diversity among marine B. licheniformis strains. This species also exhibited distinct strain distribution between seamount and non-seamount stations and was shown to be highly prevalent in non-seamount stations. This study revealed the great microdiversity of marine Bacillales and contributes to understanding the biogeographic distribution of marine bacteria in deep-sea sediments.

Trimeric l-N-carbamoylase from newly isolated Brevibacillus reuszeri HSN1: a potential biocatalyst for production of l-α-amino acids

l-N-carbamoylase was isolated from Brevibacillus reuszeri HSN1 and purified to homogeneity in three steps, which is a reasonably short protocol for native l-N-carbamoylase. The enzyme purification protocol resulted in ≈60-fold purification of l-N-carbamoylase with specific activity of 145 µmol/Min/mg. The subunit and native molecular mass were found to be 44.3 and 132 kDa, respectively. Temperature and pH optima were determined as 50°C and 8.5, respectively. The enzyme had retained ≈86% activity at 50°C when incubated for 60 Min and the half-life was determined as 180 Min at 50°C. N-carbamoyl-l-methionine (l-N-CMet) was found to be a preferred substrate with Km and Vmax values of ≈13.5 mM and ≈103 µmol/Min/mg, respectively. The broad substrate specificity with derivatives of N-carbamoyl amino acids is advantageous to be a better biocatalyst for production of corresponding l-α-amino acids. The enzyme activity was enhanced by 73% in the presence of 0.8 mM Mn(2+) ion during the biotransformation. In the batch experiment, ≈97% conversion of 5.0% l-N-CMet into enantiomerically pure l-methionine was achieved in 10 H when carried out at pH 8.0, 45°C, and 15% wet (w/v) cell loading, under controlled conditions. The overall merits of this enzyme show promise as a potential biocatalyst for l-α-amino acid production.