Antimicrobial Efficacy of Allium cepa and Zingiber officinale Against the Milk-Borne Pathogen Listeria monocytogenes.

Listeria monocytogenes is an important food-borne pathogen that causes listeriosis and has a high case fatality rate despite its low incidence. Medicinal plants and their secondary metabolites have been identified as potential antibacterial substances, serving as replacements for synthetic chemical compounds. The present studies emphasize two significant medicinal plants, Allium cepa and Zingiber officinale, and their efficacy against L. monocytogenes. Firstly, a bacterial isolate was obtained from milk and identified through morphology and biochemical reactions. The species of the isolate were further confirmed through 16S rRNA analysis. Furthermore, polar solvents such as methanol and ethanol were used for the extraction of secondary metabolites from A. cepa and Z. officinale. Crude phytochemical components were identified using phytochemical tests, FTIR, and GC-MS. Moreover, the antibacterial activity of the crude extract and its various concentrations were tested against L. monocytogenes. Among all, A. cepa in methanolic extracts showed significant inhibitory activity. Since, the A. cepa for methanolic crude extract was used to perform autography to assess its bactericidal activity. Subsequently, molecular docking was performed to determine the specific compound inhibition. The docking results revealed that four compounds displayed strong binding affinity with the virulence factor Listeriolysin-O of L. monocytogenes. Based on the above results, it can be concluded that the medicinal plant A. cepa has potential antibacterial effects against L. monocytogenes, particularly targeting its virulence.

Impact and fungitoxic spectrum of Trachyspermum ammi against Candida albicans, an opportunistic pathogenic fungus commonly found in human gut that causes Candidiasis infection.

BACKGROUND: Trachyspermum ammi (commonly known as Ajwain), a medicinal plant of the Apiaceae family is scientifically acknowledged to harbor potential bioactive compounds for the treatment of gastrointestinal issues, loss of appetite, bronchial difficulties, cough, inflammation, diarrhoea, headache, hypertension, stomach discomfort, bronchitis and influenza. Candida albicans is generally a commensal fungus found in the gastrointestinal and genitourinary systems. OBJECTIVE: This study was focused on secondary metabolites of T. ammi and its effects towards candidiasis infection as caused by C. albicans. METHODS: Phytochemical components of T. ammi as a crude extract were extracted through maceration method using three polar (ethanol, methanol and water) and two non-polar (chloroform and diethyl ether) solvents and subjected to 14 phytochemical tests. Further, the crude extract of T. ammi was analyzed over gas chromatography-mass spectroscopy (GC-MS) and Fourier transform infrared spectroscopy (FTIR). Evaluation of antimicrobial property of the extract was carried out by minimum fungal concentration (MFC) and minimal inhibitory concentration (MIC). In addition, cell reduction assay was performed using flowcytometry to confirm the antifungal effect of Ajwain crude extract. RESULTS: The aqueous extract showed high presence of phytochemicals including alkaloids, carbohydrates, flavonoids, resins, steroids, tannins, inorganic acids, organic acids, phenolic compounds, amino acids, protein and coumarins. GCMS analysis revealed seven bioactive compounds, in which thymol was detected in significant amount in the chromatogram. FTIR performance showed the presence of various stretching vibration including OH, CH, CC, CO, CN and COC. However, the MFC and MIC of Ajwain extracts using different solvent showed that the methanolic extract possesses maximum antifungal efficacy at 250 µg/ml and 15.6 µg/ml, respectively. In addition, cell reduction assay exhibited significant cell reduction in Ajwain methanolic extract compared to the other crude extracts used in the study. CONCLUSION: Overall, the findings revealed that Ajwain methanolic crude extract has antifungal activity against C. albicans; however, that further needs to be established at molecular level.

A novel prophenoloxidase, hemocyanin encoded copper containing active enzyme from prawn: gene characterization.

The copper containing prophenoloxidase enzyme plays a crucial role in the defense system of arthropods, especially crustaceans and insects. In this study, we have reported a full length cDNA of prophenoloxidase identified from the constructed cDNA library of freshwater prawn Macrobrachium rosenbergii by genome sequence FLX technology. The identified full length M. rosenbergii prophenoloxidase (MrProPO) consists of 3378 base pairs (bp) with an open reading frame (ORF) of 2099 bp. This ORF encoded a polypeptide of 700 amino acids (aa) with an estimated molecular mass of 80 kDa and a predicted isoelectric point (pI) of 6.7. The motif analysis of MrProPO shows two copper binding sites (CuA and CuB) along with hemocyanin signatures and a thiol-ester like motif. MrProPO exhibited the maximum similarity (97%) with ProPO from Macrobrachium nipponense and is closely clustered with other crustacean ProPO in the phylogenetic tree. Bioinformatics analysis suggests that MrProPO is a member of the prophenoloxidase family, due to the conserved domains, motifs and similarity with other known ProPOs. The 3D structural analysis of MrProPO reveals that it has more random coils, moderate α-helices, few extended ß-sheets and a very few ß-turns. Among the 700 aa of MrProPO, 355 (50.71%), 206 (29.43%), 110 (15.71%) and 29 (4.14%) amino acids are responsible for random coils, α-helices, extended ß-sheets and ß-turns respectively. The gene expression results indicate MrProPO is widely distributed in all the tissues studied, but significantly (P<0.05) highest expression was observed in hepatopancreas. The relative expression of mRNA was quantified in hepatopancreas after being infected with virus [white spot syndrome baculovirus (WSBV) and M. rosenbergii nodovirus (MrNV)] and bacteria (Aeromonas hydrophila and Vibrio harveyi) using real-time PCR. MrProPO mRNA transcription significantly (P<0.05) increased at 24h post injection (p.i.) with subsequent decrease at 48 h p.i. in both viral and bacterial infected prawns. The highest enzyme activity was observed in hepatopancreas, which was also significantly higher (P<0.05) than detected in other tissues. Similar to gene expression results, the enzyme activity reached the peak at 24h p.i. and then the activity started decreasing. Overall results indicate that MrProPO is very likely to participate in the acute response against pathogen entry in prawns.

Fish lily type lectin-1 contains ß-prism architecture: immunological characterization.

In this study we report a full-length lily type lectin-1 (CsLTL-1) identified from striped murrel, Channa striatus. CsLTL-1 was identified from the established C. striatus cDNA library using GS-FLX™ genome sequencing technology and was found to contain 354 nucleotide base pairs and its open reading frame (ORF) encodes a 118 amino acid residue. CsLTL-1 mRNA is predominately expressed in the gills and is up-regulated upon infection with fungus (Aphanomyces invadans) and bacteria (Aeromonas hydrophila). Hemagglutination studies with recombinant CsLTL-1 show that, at 4µg/ml agglutinates occurs in a calcium independent manner and is inhibited in the presence of d-mannose (50mM) and d-glucose (100mM). The CsLTL-1 sequence was completely characterized using various bioinformatics tools. CsLTL-1 peptide contains a mannose binding site at 30-99 along with its specific motif of ß-prism architecture. The phylogenetic analysis showed that CsLTL-1 clustered together with LTL-1 from Oplegnathus fasciatus. CsLTL-1 protein 3D structure was predicted by I-Tasser program and the model was evaluated using Ramachanran plot analysis. The secondary structure analysis of CsLTL-1 reveals that the protein contains 23% ß-sheets and 77% coils. The overall results showed that CsLTL-1 is an important immune gene involved in the recognition and elimination of pathogens in murrels.