Molecular identification and genetic diversity among Photorhabdus and Xenorhabdus isolates

Green synthesis of silver nanoparticles derived from lemon and pomegranate peel extracts to combat multidrug-resistant bacterial isolates

BACKGROUND

Multidrug-resistant (MDR) bacteria are acknowledged as one of the main factors contributing to chronic illnesses and fatalities globally. Numerous diseases, including bloodstream infections, pneumonia, urinary tract infections, and surgical site infections, can be brought on by MDR bacteria. Therefore, a crucial topic of continuing research is the development of a novel and different treatment for MDR microbial pathogens. This work is introduce an alternative method for elimination of MDR bacterial isolates which are causative agents of urinary tract infection among people in Egypt. In our study, we need a novel strategy to combat MDR bacteria by green-synthesized metal nanoparticles (MNPs). That is due to the ability of MNPs to penetrate the cell wall and the cell membrane of gram-positive and gram-negative bacteria.

METHODS

Clinical isolates of MDR bacteria had their antibiotic susceptibility assessed before being molecularly identified using 16 s rRNA, sequencing, and phylogenetic analysis. Also, genetic profiles of isolated strains were performed using ISSR and SDS-PAGE. Finally, characterized plant-mediated silver nanoparticles derived from lemon and pomegranate peel extracts were evaluated against isolated multidrug-resistant bacterial stains.

RESULTS

In our present trial, one-hundred urine samples were collected from 71 females and 29 males complaining of UTI (urinary tract infection) symptoms. One-hundred microbial isolates were isolated, including 88-g negative and only 8-g positive bacteria in addition to four yeast isolates (Candida species). A total of 72% of the isolated bacteria showed MDR activity. The most prevalent MDR bacterial isolates (Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus faecalis, and Klebsiella pneumoniae) were identified through 16S rDNA PCR sequencing as with accession numbers OP741103, OP741104, OP741105, OP741106, and OP741107, respectively. Lemon and pomegranate-mediated silver nanoparticles [Ag-NPs] were characterized by UV spectroscopy, FTIR, XRD, and TEM with average size 32 and 28 nm, respectively. Lemon and pomegranate-mediated silver nanoparticles [Ag-NPs] showed an inhibitory effect on the selected five MDR isolates at MIC 50 and 30 µg/mL, respectively. These common bacterial isolates were also genetically examined using ISSR PCR, and their total protein level was evaluated using SDS-PAGE, showing the presence of distinct genetic and protein bands for each bacterial species and emphasizing their general and protein composition as a crucial and essential tool in understanding and overcoming MDR behavior in UTI patients.

CONCLUSIONS

Lemon and pomegranate-mediated silver nanoparticles [Ag-NPs] were found to have an inhibitory effect on MDR isolates. Therefore, the study suggests that [Ag-NPs] could be a potential treatment for MDR UTI infections caused by the identified bacterial species.

Isolation of Pseudomonas syringae pv. Tomato strains causing bacterial speck disease of tomato and marker-based monitoring for their virulence

BACKGROUND

The bacterial speck disease of tomato caused by a bacterial pathogen Pseudomonas syringae pv. tomato is a most important disease causing severe crop losses.

METHODS AND RESULTS

Present study was conducted to investigate and characterize the population diversity of P. syringae pv. tomato pathogen isolated from infected tomato plants from various regions of Egypt. Significant variation among the isolates was observed which demonstrated considerable virulence. All isolates were pathogenic and the CFU population recovered from inoculate tomato leaves by isolate Pst-2 was higher than other isolates. Genetic disparity among the isolates was investigated by PCR analysis by amplifying hrpZ gene using random amplified polymorphic DNA (RAPD), sequence-related amplified polymorphism (SRAP), and inter-simple sequence repeats (ISSR) markers. The amplified products for ITS1 were found to have 810 bp length whereas 536 bp length was observed for hrpZ gene using primer pairs (1406-f/23S-r) and (MM5-F, MM5-R) respectively. The restriction analysis of amplified regions "ITS" and hrpZ by using 5 and 4 endonucleases respectively demonstrated slight variation among the bacterial isolates. The results of RAPD, ISSR and SRAP showed higher polymorphism (60.52%) within the isolates which may assist for successful characterization by unique and specific markers based on geographical distribution, origin and virulence intensity.

CONCLUSION

The results of present study suggested that the use of molecular approach may provide successful and valuable information to differentiate and classify P. syringae pv. tomato strains in future for the detection and confirmation of pathogenicity.

Evaluating genetic diversity of geographically diverse populations of Embelia ribes Burm f., a highly medicinal woody liana from the Western Ghats of India, using random amplified polymorphic DNA (RAPD) and intersimple sequence repeats (ISSR) markers

BACKGROUND

Embelia ribes Burm f. (Primulaceae) is a medicinal and vulnerable woody liana distributed throughout India. Embelin, a well-recognized active phytoconstituents in berries, is commonly used in ayurvedic formulations. Due to over-exploitation, the status of the plant is vulnerable. Previous studies on this species mainly focused on its phytochemical analysis, which led to overexploitation and loss of the germplasm.

METHODS AND RESULTS

In the present study, 20 RAPD and 18 ISSR markers were employed to assess genetic divergence in 40 genotypes of E. ribes collected from different parts of the Western Ghats of India. In RAPD analysis, all 40 accessions with 20 RAPD primers amplified 282 fragments, with 83.91% average polymorphism and with an average of 14.10 bands per primer. The size of amplicons varied from 200 to 2500 bp. While, ISSR primers produced 203 fragments of which 161 were polymorphic with an average of 11.28 bands per primer with 73.25% average polymorphism. The size of amplicons ranges from 200 to 2500 bp. RAPD and ISSR markers were also assessed by calculating polymorphic information content (PIC) to discriminate the genotypes; the average PIC value for RAPD, ISSR, and combined RAPD + ISSR markers obtained was more than 0.50 suggesting the informativeness of markers. UPGMA analysis based on Jaccard's similarity coefficient for RAPD, ISSR, and RAPD + ISSR data reveals that 40 accessions of E. ribes were depicted in four clusters. The clustering pattern of all individuals in PCoA analysis agreed with the UPGMA dendrograms, which further confirms the genetic relationships explained by cluster analysis. AMOVA analysis of RAPD, ISSR, and combined marker system revealed variation within the population, ranging from 41 to 44%, and among the population, it ranged from 56 to 59%.

CONCLUSION

The present study provides an optimized method for evaluating the genetic diversity of Embelia ribes using RAPD and ISSR markers which are useful for further sustainable utilization and conservation of natural populations in the Western Ghats of India.

Genome sequence of the non-conventional wine yeast Hanseniaspora guilliermondii UTAD222 unveils relevant traits of this species and of the Hanseniaspora genus in the context of wine fermentation

Hanseanispora species, including H. guilliermondii, are long known to be abundant in wine grape-musts and to play a critical role in vinification by modulating, among other aspects, the wine sensory profile. Despite this, the genetics and physiology of Hanseniaspora species remains poorly understood. The first genomic sequence of a H. guilliermondii strain (UTAD222) and the discussion of its potential significance are presented in this work. Metabolic reconstruction revealed that H. guilliermondii is not equipped with a functional gluconeogenesis or glyoxylate cycle, nor does it harbours key enzymes for glycerol or galactose catabolism or for biosynthesis of biotin and thiamine. Also, no fructose-specific transporter could also be predicted from the analysis of H. guilliermondii genome leaving open the mechanisms underlying the fructophilic character of this yeast. Comparative analysis involving H. guilliermondii, H. uvarum, H. opuntiae and S. cerevisiae revealed 14 H. guilliermondii-specific genes (including five viral proteins and one β-glucosidase). Furthermore, 870 proteins were only found within the Hanseniaspora proteomes including several β-glucosidases and decarboxylases required for catabolism of biogenic amines. The release of H. guilliermondii genomic sequence and the comparative genomics/proteomics analyses performed, is expected to accelerate research focused on Hanseniaspora species and to broaden their application in the wine industry and in other bio-industries in which they could be explored as cell factories.

RAPD and ISSR marker assessment of genetic diversity in Citrullus colocynthis (L.) Schrad: a unique source of germplasm highly adapted to drought and high-temperature stress

Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) shows high levels of variation in fruit color, fruit stripe pattern, seed coat color, and size. Thirty-eight accessions of C. colocynthis plants from different parts of semi-arid Rajasthan were collected and genetic diversity was assessed using random-amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Out of 65 RAPD decamer primers, 50 primers produced 549 scorable bands of which 318 were polymorphic. Polymorphic banding patterns with the number of amplified fragments varied from 5 (OPA-08 and OPF-9) to 19 (OPT-20) in the molecular size range of 150-6000 bp. Percent polymorphism ranged from 22.2% (OPA-09) to 83.3% (OPE-12) with 55.14% polymorphism. Out of the 20 ISSR primers screened, 13 primers produced 166 amplification products, of which 99 were polymorphic. The number of bands amplified per primer varied between 9 (UBC-807, 802) and 16 (UBC-803, 812) with average band size between 250 and 4000 bp. Percent polymorphism ranged from 45.4% (UBC-815) to 73.3% (UBC-814) with 65.05% polymorphism. Dendrogram constructed on the basis of RAPD + ISSR polymorphism separated the accessions into four distinct clusters at 72% variation with Jaccard's similarity coefficient ranging from minimum 0.64 to 0.95. The matrices for RAPD and ISSR were also compared using Mantel's test and obtained correlation value (r = 0.7947). Discriminating power of RAPD and ISSR markers was assessed by calculating polymorphic information content, multiplex ratio, marker index, and resolving power. Approx. 50% RAPD and ISSR markers showed PIC value and heterozygosity (H) ≥ 0.50, indicating marker as informative. The primers that showed higher polymorphism had higher RP, MR, and MI values.