Shigella Dysenteriae Research Articles

Alocasia macrorrhiza rhizome lectin inhibits growth of pathogenic bacteria and human lung cancer cell in vitro and Ehrlich ascites carcinoma cell in vivo in mice

Cancer and antibiotic resistance represent significant global challenges, affecting public health and healthcare systems worldwide. Lectin, a carbohydrate-binding protein, displays various biological properties, including antimicrobial and anticancer activities. This study focused on anticancer and antibacterial properties of Alocasia macrorrhiza lectin (AML). AML, with a molecular weight of 11.0 ± 1.0 kDa was purified using Ion-exchange chromatography, and the homotetrameric form was detected by gel-filtration chromatography. It agglutinates mouse erythrocytes, that was inhibited by 4-Nitrophenyl-α-d-mannopyranoside. Maximum hemagglutination activity was observed below 60 °C and within a pH range from 8 to 11. Additionally, it exhibited moderate toxicity against brine shrimp nauplii with LD50 values of 321 μg/ml and showed antibacterial activity against Escherichia coli and Shigella dysenteriae. In vitro experiments demonstrated that AML suppressed the proliferation of mice Ehrlich ascites carcinoma (EAC) cells by 35 % and human lung cancer (A549) cells by 40 % at 512 μg/ml concentration. In vivo experiments involved intraperitoneal injection of AML in EAC-bearing mice for five consecutive days at doses of 2.5 and 5.0 mg/kg/day, and the results indicated that AML inhibited EAC cell growth by 37 % and 54 %, respectively. Finally, it can be concluded that AML can be used for further anticancer and antibacterial studies.

Phytochemical Profile and Antibacterial Effects of Zingiber Officinale Root Extract on Some Enteric Bacterial Pathogens

The majority of Africans today depend either totally or partially on medicinal plants for the treatment of various diseases. In some rural communities, ethno-medicine is sometimes the only form of healthcare. Therefore, this work aimed to determine the phytochemical constituents and antibacterial potentials of Z. officinale, which is one of the medicinal plants used by some people. The active ingredients of the plant were first extracted using water and ethanol as solvents. This was followed by the phytochemical analysis of the extracts. Furthermore, the antibacterial effects of aqueous and ethanolic extracts of Z. officinale on Escherichia coli, Salmonella typhi and Shigella dysenteriae isolated from faeces of gastroenteritis patients were evaluated using the agar diffusion technique (punch method). Additionally, a two-fold tube dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts. The mean values of zones of inhibition obtained were statistically analyzed using ANOVA. The least significant difference was determined according to the LSD test at P<0.05. Phytochemical analysis revealed the presence of saponin, alkaloids, flavonoids, and tannins. The antibacterial results showed that both the aqueous and ethanolic extracts have antibacterial effects against all the test organisms but at varying degrees. At the 500mg/ml concentration, the ethanolic extract of Zingiber officinale produced a zone of inhibition of 21.00b against S. dysenteriae and 20.00b against E. coli and S. typhi. On the other hand, the 500mg/ml concentration of the aqueous extract had a zone of inhibition of 20.00b against S. dysenteriae, 16.00b against E. coli and 10.00b against S. typhi. The findings from this study lend credence to the claims that Z. officinale extracts possess antibacterial potentials. Also, the higher potency in ethanolic than in aqueous extract suggests that the potency might be dose and solvent dependent. Conclusively, owing to the findings from this study, the active ingredients of Z. officinale could be harnessed and employed in the development of novel antibacterial therapies.

The Phytochemical Composition and Antibacterial Effects of Allium sativum Clove Extracts on Some Enteric Bacterial Pathogens

In this study, the phytochemicals present in the cloves of Allium sativum were determined, and their antibacterial activities against some enteric bacterial pathogens were assessed. The phytochemical constituents were determined after the extraction process was completed using water and ethanol as the solvents. Furthermore, the aqueous and ethanolic extracts of A. sativum were tested against Escherichia coli, Salmonella typhi and Shigella dysenteriae isolated from faeces of gastroenteritis patients. The agar diffusion technique (punch method) was used for this. Additionally, the extracts' minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The mean values of the zones of inhibition obtained were statistically analyzed using ANOVA. The least significant difference was determined according to the LSD test at P<0.05. The results of the phytochemical analysis revealed the presence of saponin, alkaloids, flavonoids, and tannins. Furthermore, the antibacterial susceptibility test showed that the aqueous and ethanolic extracts possess antibacterial properties against all the test organisms. The ethanolic extract at the concentration of 500mg/ml had zones of inhibition of 29.00b against E. coli, 24.00b against S. dysenteriae and the lowest 20.00b against S. typhi. On the other hand, at that same concentration, the aqueous extract had zones of inhibition of 20.00b against E. coli and 18.00b against S. dysenteriae and S. typhi. This study suggests that A. sativum extracts possess antibacterial properties. Furthermore, since the ethanolic extract was more effective than the aqueous extract, it could be that the antibacterial potency of A. sativum is solvent-dependent. In conclusion, the findings from this study suggest that further purification of the constituents of the plant might lead to the development of novel antibiotics.

Antibacterial Activity Test of Endophytic Fungi Extraction Kasumba Turate (Carthamus tinctorius L.) Leaves From Galesong against Digestive Tract Infection

Digestive tract infection is still a significant health problem in Indonesia, it caused by pathogenic bacteria. Kasumba turate (Carthamus tinctorius L.) is a medicinal plant that empirically used as measles drug with several compounds such as flavonoids, quinocalcones, polyacetylenes, alkaloids, fatty acids, steroids, proteins and polysaccharides and kasumba turate (Carthamus tinctorius L.) leaves are believed to have antimicrobial activity against several microbes pathogens such as E.coli and S.aureus. This research was conducted to determine endophytic fungi isolates from kasumba turate (Carthamus tinctorius L.) leaves that can provide activity against bacteria that cause digestive tract infections seen from the bioautography profile determination. Three endophytic fungi isolated from kasumba turate (Carthamus tinctorius L.) leaves were purified and observe macroscopically. After purification an antibacterial screening test was conducted by observing the inhibition zone of each isolate; the isolate with largest inhibition zone is IFEDKT-03. Isolates were fermented for 21 days, mycelia and supernatant were separated, and extraction was performed. The endophytic fungi extract of kasumba turate (Chartamus tinctorius L.) leaves has antibacterial activity against Escherichia coli, Salmonella typhi, Shigella dysenteriae, and Vibrio cholera as indicated by Rf values of 0.23, 0.41, 0.49, 0.56, 0.70 and 0.76

Pengaruh penambahan sari buah naga merah pada yoghurt susu kedelai serta uji aktivitas antibakteri

Food is one of the most important needs for humans because it relates to daily nutritional needs. The solution to this problem is to consume food with good nutritional content supported by appropriate food processing innovations. Milk can be drunk directly or processed into various forms of food and drinks with milk-based ingredients, such as yogurt. This study aims to make yogurt products from soy milk using red dragon fruit juice as a substitute for sugar and to test their antibacterial activity in inhibiting Salmonella typhi and Shigella dysenteriae bacteria. This study used a completely randomized design (CRD) with 3 treatments, namely the addition of red dragon fruit juice with concentrations of 5%, 10%, and 15%, 3 replications, and the diffusion method for testing antibacterial activity. The results showed that the best yoghurt formula was obtained from F3 (yoghurt with the addition of 15% concentration of red dragon fruit juice). The panelist hedonic test gives values ranging from slightly like to like for color, aroma, taste, and texture; for organoleptic F3, these are: color (dark pink), taste (sour), texture (liquid-thick), and aroma (typical); pH 3.49; TAT 1.39%; Lactic Acid Bacteria (LAB) 2.09 x 1010 CFU/mL; and also had an average diameter of inhibition of 18.96 mm against Salmonella thypi (P<0.05) and 20.10 mm against Shigella dysenteriae (p<0.05). Soy milk yogurt with the addition of varying concentrations of red dragon fruit juice has antibacterial activity.

A Comprehensive Review on Shiga Toxin Subtypes and Their Niche-Related Distribution Characteristics in Shiga-Toxin-Producing E. coli and Other Bacterial Hosts.

Shiga toxin (Stx), the main virulence factor of Shiga-toxin-producing E. coli (STEC), was first discovered in Shigella dysenteriae strains. While several other bacterial species have since been reported to produce Stx, STEC poses the most significant risk to human health due to its widespread prevalence across various animal hosts that have close contact with human populations. Based on its biochemical and molecular characteristics, Shiga toxin can be grouped into two types, Stx1 and Stx2, among which a variety of variants and subtypes have been identified in various bacteria and host species. Interestingly, the different Stx subtypes appear to vary in their host distribution characteristics and in the severity of diseases that they are associated with. As such, this review provides a comprehensive overview on the bacterial species that have been recorded to possess stx genes to date, with a specific focus on the various Stx subtype variants discovered in STEC, their prevalence in certain host species, and their disease-related characteristics. This review provides a better understanding of the Stx subtypes and highlights the need for rapid and accurate approaches to toxin subtyping for the proper evaluation of the health risks associated with Shiga-toxin-related bacterial food contamination and human infections.

Green synthesis of silver nanoparticles using Houttuynia cordata Thunb rhizome extracts and their antibacterial potential against common foodborne pathogens

SummaryThe biological synthesis of functionalised nanoparticles using plant materials is considered more cost‐effective and eco‐friendly than chemical and physical methods. Hence, this study demonstrated the synthesis of silver nanoparticles (AgNPs) using Houttuynia cordata Thunb rhizome (HCR). The extract, prepared with distilled water, provided the required phytochemical components, such as flavonoids, terpenoids, phenols, proteins and other essential bio‐reducing agents. The AgNPs were exposed to reaction conditions, such as temperatures, pH values and AgNO3 concentrations, to identify the optimum synthesis condition and explore their impacts on particle size and antibacterial action against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Salmonella enterica and Shigella dysenteriae) foodborne pathogens. The formation of AgNPs was indicated by specific surface plasmon resonance (SPR) intensity at 440–450 nm and colour changes under different reaction conditions. The structure and size distribution characterised by SEM and TEM revealed that the AgNPs exhibited a spherical‐shaped structure with irregular contours, regular distribution and aggregation. Although the average particle size ranged from 2 to 100 nm, relatively smaller sizes were detected at 10 mM (54.30), 80 °C (49.50 nm) and pH 6 (60.16 nm) conditions. The FTIR spectrum and EDX spectral signals affirmed the presence of reducing and stabilising agents in HCR extract, following the reduction of AgNPs from Ag+ to Ag0. AgNPs also exhibited excellent antibacterial activity against S. aureus, S. enterica and Sh. dysenteriae, indicating a broad spectrum for various applications in the food and pharmaceutical industries.

Anti-Shigellosis Activity and Mechanisms of Action of Extracts from Diospyros gilletii Stem Bark

Shigellosis is a pathological condition that affects the digestive system and possibly causes diarrhoea. Shigella species, which are responsible for this disease, are highly contagious and spread through contaminated food and water. The increasing development of resistance by Shigella species necessitates the urgent need to search for new therapies against diarrhoea-causing shigellosis. The scientific validation of medicinal plants, such as Diospyros gilletii, which is used for the traditional treatment of diarrhoeal conditions is worthwhile. The present study aims to investigate the antibacterial activity of extracts from D. gilletii against selected Shigella species. Extracts from D. gilletii stem bark were prepared by maceration using various solvents. The antibacterial activity of D. gilletii extracts was evaluated in Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei using a microdilution method, whereas a cytotoxicity test was performed on Vero and Raw cells using resazurin-based colorimetric assays. Bacterial membrane-permeability studies were evaluated using propidium iodide (PI)- and 1-N-phenyl-naphthylamine (NPN)-uptake assays, whereas inhibition and eradication tests on bacterial biofilms were carried out by spectrophotometry. As a result, methanol, ethanol and hydroethanol (water: ethanol; 30:70, v/v) extracts of D. gilletii inhibited the growth of S. boydii, S. flexneri and S. sonnei, with minimum inhibitory concentration (MIC) values ranging from 125 to 500 µg/mL, without toxicity to Vero and Raw cells. Time-kill kinetics revealed bactericidal orientation at 2 MIC and 4 MIC and a bacteriostatic outcome at 1/2 MIC. The mechanistic basis of antibacterial action revealed that D. gilletii extracts inhibited and eradicated Shigella biofilms and promoted the accumulation of NPN and PI within the inner and outer membranes of bacteria to increase membrane permeability, thereby causing membrane damage. This novel contribution toward the antibacterial mechanisms of action of D. gilletii extracts against Shigella species substantiates the use of this plant in the traditional treatment of infectious diarrhoea.

Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53

Abstract In the present work, manganese–copper co-infused nickel oxide nanoparticles (MnCu co-doped NiO NPs) were formulated via a green process using Carica papaya extract. The MnCu co-doped NiO NPs were characterized by X-ray diffraction (XRD), UV–Vis, Fourier transform infrared, field emission scanning electron microscope, energy dispersive X-ray analysis, and photoluminescence (PL) spectrum. The XRD pattern demonstrated that synthesized MnCu co-doped NiO NPs exhibit cubic structure. On the PL spectrum, various surface defects were identified. MnCu co-doped NiO NPs exhibited ferromagnetic properties at 37°C. The antimicrobial activity of green synthesis MnCu co-doped NiO NPs against human pathogens (Escherichia coli, Streptococcus pneumoniae, Bacillus megaterium, Bacillus subtilis, Shigella dysenteriae, Pseudomonas aeruginosa) and Candida albicans as fungal strains were demonstrated. The MnCu co-doped NiO NPs treatment considerably reduced MDA-MB-231 cell viability while not disturbing HBL-100 cell viability. Different fluorescent staining analyses revealed that MnCu co-doped NiO NPs induced nuclear and mitochondrial damage to improve free radical production, altering mitochondrial membrane protein potential, which led to apoptotic cell death in MDA-MB-231 cells. The MnCu co-doped NiO NP treatment enhanced pro-apoptotic protein expression and inhibited the cell cycle at the S phase in MDA-MB-231 cells. This makes it easy, cheap, and environmentally friendly to make MnCu co-doped NiO NPs using C. papaya extract, which has excellent antimicrobial properties.

Evaluation of in-vitro antibacterial activity of extracts of Calpurina aurea, Vernonia amygdalina and Rumex nepalensis in Goba district, southeastern Ethiopia

ABSTRACT The great majority of the rural populations in developing countries relies on traditional medicinal plants for treating different diseases. This study investigated the antibacterial activity of Calpurnia aurea, Vernonia amygdalina, and Rumex nepalensis collected from Goba District, Bale Zone, southeastern Ethiopia against five human bacterial test pathogens (Escherichia coli, Salmonella typhi, Staphylococcus aureus, Shigella dysenteriae and Pseudomonas aeruginosa). Plant specimens were extracted with 70% ethanol, 80% methanol, petroleum ether, and distilled water. The crude extracts were evaluated against test pathogens using agar well diffusion and micro dilution methods. The highest yield was achieved by aqueous extract of C. aurea leaf (16.6 mg/ml). The antibacterial activity of the plants’ extracts ranged from a zone of inhibition of 5.4 ± 0.4 mm to 23.0 ± 0.3 mm. Overall, the highest zone of inhibition (23 ± 0.3 mm) and the highest activity index (AI) comparable to 80% of inhibition by standard antibiotic ciprofloxacin (5 µg/disc) were revealed by the methanol extract of C. aurea leaves against S. aureus. The smallest minimum inhibitory concentration (0.78 mg/ml) was achieved by 80% methanol extracts of C. aurea roots and V. amygdalina leaves against S. aureus and E. coli, respectively. Our study revealed promising antibacterial activity of the evaluated plants.. Further studies are required to evaluate the active ingredients at the in-vitro and in-vivo levels.

Production of egg yolk antibody (IgY) against a chimeric protein containing IpaD, StxB, and TolC antigens from Shigella: An investigation of its prophylactic effects against Shiga toxin (Stx) and Shigella dysenteriae in vitro and in vivo

Shigella is a major problem in developing countries. Immunoglobulin Y (IgY) can be used for prophylaxis and neutralize bacteria. The aim of this study was to produce IgY against the chimeric protein containing IpaD, StxB, and TolC antigens from Shigella, investigate its prophylactic and neutralizing effects against Stx and Shigella dysenteriae. The nucleotide sequence corresponding to the chimeric protein was cloned into pET28a plasmid and expressed in E. coli BL21 (DE3). Protein expression was confirmed by SDS-PAGE and the recombinant protein was purified by Ni-NTA affinity chromatography. The 150 μg of chimeric protein was mixed with Freund's adjutant and injected into laying hens (Leghorn). IgY was purified using PEG6000 precipitation. Antibody titer in the serum and egg yolk was evaluated by ELISA. IgY challenge against 1,10 and 50 LD50 of Stx and S. dysenteriae was investigated. A 60.6 kDa recombinant protein was confirmed by SDS-PAGE. ELISA showed that the antibody titer was significantly increased. MTT assay [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] showed that at 16 μmol/L, IgY protected HeLa cells against Stx. Treatment of mice with 1000 and 1500 μg IgY leads to complete survival of the mice against 1LD50 toxin and 4000 μg of IgY led to complete survival against 1LD50, also 70% and 30% survival against 10 and 50 LD50S. dysenteriae. This study showed that IgY produced against Stx and Shigella virulence factors could cause high protective effects against bacteria and toxins.

Cyclic Multiple Primer Generation Rolling Circle Amplification Assisted Capillary Electrophoresis for Simultaneous and Ultrasensitive Detection of Multiple Pathogenic Bacteria.

Efficient, accurate, and economical detection of pathogenic bacteria is crucial in ensuring food safety and preventing foodborne illnesses. How to fulfill the highly sensitive and simultaneous detection of multiple trace pathogenic bacteria is a big challenge. In this work, capillary electrophoresis coupled with a cyclic multiple primer generation rolling circle amplification (cyclic MPG-RCA) was studied for highly sensitive and simultaneous detection of three kinds of pathogenic bacteria. The cyclic MPG-RCA was based on a carefully designed clover-shaped DNA probe, in which three "leaves" corresponded to three types of aimed pathogenic bacteria: Shigella dysenteriae (S. dysenteriae), Salmonella enterica subsp. enterica serovar Typhi (S. Typhi), and Vibrio parahaemolyticus (V. parahaemolyticus). Under the optimal experimental conditions, the limits of detection (S/N = 3) of this method for bacterial target DNA were 11.4 amol·L-1 (S. dysenteriae), 4.88 amol·L-1 (S. Typhi), and 14.9 amol·L-1 (V. parahaemolyticus), and the conversion concentrations for the target bacteria were 10 colony-forming units (CFU)·mL-1 (S. dysenteriae), 3 CFU·mL-1 (S. Typhi), and 12 CFU·mL-1 (V. parahaemolyticus). This method had been applied to the detection of tap water samples with good results, which proved that it could be used as an effective tool for trace pathogenic bacteria monitoring in foods, environments, and medicines.

Antimicrobial, antioxidant and antiproliferative activities of a galactose-binding seed lectin from Manilkara zapota

A seed lectin from Manilkara zapota (MZSL) was purified using ammonium sulphate precipitation and affinity chromatography. Hemagglutination activity, neutral sugar content and physicochemical properties of the lectin were determined and toxicity was checked by brine shrimp toxicity assay. Antimicrobial, antioxidant as well as in vitro anticancer activities of MZSL were also evaluated. Our findings showed the molecular weight of MZSL to be 33.0 ± 1 kDa. Minimum hemagglutination concentration of the lectin was 15.625 μg/ml. With a neutral sugar content of 6.32 %, the lectin was fully active at a temperature range of 30–50 °C and pH 7.0–8.0 and it was mildly toxic with an LC50 value of 107.93 μg/ml. The lectin demonstrated bacteriostatic activity against gram-positive bacteria in contrast to gram-negative bacteria at a concentration of 31.25 μg/ml, agglutinated Staphylococcus aureus and Shigella dysenteriae and exerted fungistatic activity against Aspergillus niger. MZSL dose-dependently reduced the formation of biofilm by E. coli. DPPH assay confirmed its antioxidant activity with an IC50 value of 96.42 μg/ml. MZSL showed 21.64 % growth inhibition against Ehrlich ascites carcinoma (EAC) cells at 80 μg/ml whereas its antiproliferative potential against MCF-7 and A-549 cancer cell lines became evident with IC50 values of 70.66 μg/ml and 107.64 μg/ml, respectively.

Clinico-bacteriological Study and Molecular Detection of Campylobacter in Childhood Diarrhoea: A Cross-sectional Study

Introduction: Campylobacter infections cause diarrhoeal diseases as frequently as Salmonella and Shigella infections. The prevalence of Campylobacter infection among children with acute diarrhoea in developing countries ranges from 5-35%. Diagnosing Campylobacter infections is challenging as the organism is difficult to isolate, grow, and identify. Currently, no best-practice clinical or public health laboratory guidelines exist for laboratory diagnosis of Campylobacter infections. Aim: To explore the clinical and bacterial aspects of childhood diarrhoea, emphasising the prevalence and molecular detection of Campylobacter. Materials and Methods: A hospital-based cross-sectional descriptive study was conducted with 55 stool samples of children under five with diarrhoea or dysentery at the Department of Microbiology, JSS Medical College, Mysuru, Karnataka, India, from October 2016 to September 2017. All stool samples were inoculated onto Campylobacter selective and non selective media with filtration and incubated in microaerophilic conditions. The culture isolates were identified by standard phenotypic tests. Molecular characterisation of Campylobacter was performed targeting the Campylobacter adhesion to fibronectin F (cadF) gene. The presence of a phylogenetically conserved 16S ribosomal Ribonucleic Acid (16SrRNA) domain was studied, followed by specific detection of pathogenic Campylobacter species. The Statistical Package for Social Sciences (SPSS) version 22.0 was used for statistical analysis. Descriptive statistics like percentage, mean, and Standard Deviation (SD) were applied. Results: Campylobacter was isolated by culture in one out of 55 stool samples. The isolate was confirmed to be Campylobacter jejuni by phenotypic tests. Campylobacter genus-level Polymerase Chain Reaction (PCR) was positive for 6 samples (10.9%). Six positive samples were subjected to species-level PCR; all were positive for C. jejuni. Out of 55 stool samples, two diarrheagenic Escherichia coli, two Shigella sonnei, one Shigella dysenteriae, and one Salmonella enterica serovar Typhi were also identified. Conclusion: Culture is insufficiently sensitive for diagnosing Campylobacter infection compared with nucleic acid-based diagnostics. Nucleic acid-based diagnostics offer increased sensitivity, can determine both the presence and burden of infection, and can distinguish between Campylobacter infections at the species level. Therefore, PCR is recommended, if feasible, as the preferred diagnostic modality for detecting Campylobacter infection.

4-Chloroskimmetine-based derivatives as potential anticancer and antibacterial prospects: Their synthesis and in vitro inspections

Cancer and bacterial infections are among the most high-interest health threats facing humanity. The growing resistance to current-found anticancer and antibacterial drugs necessitates the exploration of new, effective agents. To synthesize some of them, 4-chloroskimmetine (4-CSM), with undefined biological effects, was used as a building block to create thirteen of its derived coumarins. This precursor and a Bargellini reaction were used to produce the first coumarin, designated Y0. From which, twelve coumarins coded Y1-Y12 were created by esterifying Y0 with various halophenols using the SOCl2-promoted reaction. The FTIR, 1HNMR, and 13CNMR spectra were analyzed to ascertain the chemical framework of the created coumarins. Their potential to function as anticancer prospects was evaluated against six cancer-derived populations employing a preliminary MTT-facilitated methodology. These populations were MCF-7, HeLa, SKG, AMN3, SK-OV-3, and KYSE-30. On the other hand, the broth microdilution protocol was followed to specify the antibacterial activity against six high-infective aerobes. These include Pseudomonas aeruginosa, Shigella dysenteriae, Haemophilus influenza, Klebsiella pneumonia, Escherichia coli, and Salmonella typhi. The results of the first evaluation indicated that the presence of fluoride on the off-side aromatic ring afforded the most potent anticancer activity, and Y5 was the best. For the second activity, the same findings are true, but when the halogen is chloride and Y2 is the superior one. The authors concluded that 4-CSM, can be exploited to create bioactive coumarins with anticancer and antibacterial activities. Also, Y5 and Y2 can be considered promising structural templates for producing potent anticancer and antibacterial medications, respectively.

Green synthesis of silver/silver chloride nanoparticles derived from Elaeocarpus floribundus leaf extract and study of its anticancer potential against EAC and MCF-7 cells with antioxidant and antibacterial properties

In this study, the formation of Elaeocarpus floribundus leaf extract-mediated Ag/AgCl-NPs was ensured by color changes, UV–visible spectrum and it was characterized by scanning electron microscopy, transmitted electron microscopy, X-ray powder diffraction, thermal gravimetric analysis, and Fourier transform infrared spectroscopy. Synthesized Ag/AgCl-NPs scavenged DPPH and ABTS free radicals with the IC50 values of about 99.86 and 25.50 µg/ml, respectively. Among four pathogenic bacteria, Shigella dysenteriae was the most sensitive to Ag/AgCl-NPs with the lowest MIC value of 2 µg/ml. Besides, Escherichia coli failed to produce biofilm at 80 µg/ml of Ag/AgCl-NPs in a 24 to 96 h incubation period. Using MTT assay, 84.15 % EAC and 61.71 % MCF-7 cells growth inhibition caused at 32 µg/ml of Ag/AgCl-NPs. Moreover, Ag/AgCl-NPs inhibited 46.46 %, 54.54 %, and 71.28 % growth of EAC cells in mice at the doses of 1.5, 3, and 6 mg/kg/day after five consecutive days. Additionally, frequent apoptotic and altered morphological cells were found in Ag/AgCl-NPs treated groups during cellular morphological study. Moreover, incredible progress of hematological parameters (RBC, Hemoglobin, and WBC) with reduced average tumor weight and an increase in lifespan up to 73.82 % were observed in Ag/AgCl-NPs treated groups of mice and showed mild toxicity with an LC50 value of 138.56 µg/ml towards brine shrimp nauplii.

Combining experiment and energy landscapes to explore anaerobic heme breakdown in multifunctional hemoproteins.

To survive, many pathogens extract heme from their host organism and break down the porphyrin scaffold to sequester the Fe2+ ion via a heme oxygenase. Recent studies have revealed that certain pathogens can anaerobically degrade heme. Our own research has shown that one such pathway proceeds via NADH-dependent heme degradation, which has been identified in a family of hemoproteins from a range of bacteria. HemS, from Yersinia enterocolitica, is the main focus of this work, along with HmuS (Yersinia pestis), ChuS (Escherichia coli) and ShuS (Shigella dysenteriae). We combine experiments, Energy Landscape Theory, and a bioinformatic investigation to place these homologues within a wider phylogenetic context. A subset of these hemoproteins are known to bind certain DNA promoter regions, suggesting not only that they can catalytically degrade heme, but that they are also involved in transcriptional modulation responding to heme flux. Many of the bacterial species responsible for these hemoproteins (including those that produce HemS, ChuS and ShuS) are known to specifically target oxygen-depleted regions of the gastrointestinal tract. A deeper understanding of anaerobic heme breakdown processes exploited by these pathogens could therefore prove useful in the development of future strategies for disease prevention.

A rhesus macaque intragastric challenge model for evaluating the safety, immunogenicity, and efficacy of live-attenuated Shigella dysenteriae 1 vaccine candidates.

Shigellosis remains a significant global health challenge, particularly in Asia and Africa, where it is a major cause of morbidity and mortality among children. Despite the urgent need, the development of a licensed Shigella vaccine has been hindered, partly due to the lack of suitable animal models for preclinical evaluation. In this study, we used an intragastric adult rhesus macaque challenge model to evaluate the safety, immunogenicity, and efficacy of five live-attenuated Shigella dysenteriae 1 vaccine candidates, all derived from the 1617 parent strain. The vaccine strains included WRSd1, a previously tested candidate with deletions in virG(icsA), stxAB, and fnr, and four other strains-WRSd2, WRSd3, WRSd4, and WRSd5-each containing deletions in virG and stxAB, but retaining fnr. Additionally, WRSd3 and WRSd5 had further deletions in the Shigella enterotoxin gene senA and its paralog senB, with WRSd5 having an extra deletion in msbB2. Rhesus monkeys were immunized three times at two-day intervals with a target dose of 2 × 1010 CFU of the vaccine strains. Thirty days after the final immunization, all monkeys were challenged with a target dose of 2 × 109 CFU of the S. dysenteriae 1 1617 wild-type strain. Safety, immunogenicity, and efficacy were assessed through physical monitoring and the evaluation of immunologic and inflammatory markers following immunization and challenge. Initial doses of WRSd1, WRSd3, and WRSd5 led to mild adverse effects, such as vomiting and loose stools, but all five vaccine strains were well tolerated in subsequent doses. All strains elicited significant IgA and IgG antibody responses, as well as the production of antibody-secreting cells. Notably, none of the vaccinated animals exhibited shigellosis symptoms such as vomiting or loose/watery stool post-challenge, in stark contrast to the control group, where 39% and 61% of monkeys exhibited these symptoms, respectively. The aggregate clinical score used to evaluate Shigella attack rates post-challenge revealed a 72% attack rate in control animals, compared to only 13% in vaccinated animals, indicating a relative risk reduction of 81%. This study highlights the potential of this NHP model in evaluating the safety, immunogenicity, and efficacy of live-attenuated Shigella vaccine candidates, offering a valuable tool for preclinical assessment before advancing to Phase 1 or more advanced clinical trials.

Antibacterial Activity of Terminalia mantaly Stem Ethanol Extract as Hand Sanitizer Gel

Background: Hand sanitizers generally contain alcohol. However, it can cause dry and irritated skin. Therefore, it is necessary to find antibacterial alternatives that are safe for the skin. One of the plants that has antibacterial activity is Terminalia mantaly (T. mantaly). This study aimed to investigate the antibacterial activity of ethanol extract and hand sanitizer gel of T. mantaly.Methods: The antibacterial activity test against gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and gram-negative bacteria (Escherichia coli and Shigella dysenteriae) was carried out using the liquid micro dilution method. The phytochemical tests were also performed. This study was conducted at the Chemistry Laboratory, Faculty of Sains and Informatics, Universitas Jenderal Achmad Yani in April-June 2022.Results: The ethanol extract of T. mantaly stem contained secondary metabolites of alkaloids, tannins, quinones, saponins, steroids, and flavonoids. The minimum inhibitory concentration (MIC) values of T. mantaly stem ethanol extract against Escherichia coli, Shigella dysenteriae, Staphylococcus aureus, Streptococcus pyogenes were 0.63%, 0.63%, 0.16%, and 0.16%, whereas the hand sanitizer gel gave MIC values of 0.63%; 0.31%; 0.16%; and 0.16% respectively. The minimum bactericidal concentration (MBC) values of T. mantaly stem ethanol extract and hand sanitizer gel had the same results, namely 2.50%, 0.16%, 1.25%, and 1.25%. The physical stability of the hand sanitizer gel from the ethanol extract of T. mantaly stem met the physical stability standards of the gel. Conclusions: The ethanol extract of the T. mantaly stems has stronger antibacterial activity against gram-positive bacteria than against gram- negative bacteria.

Bioprospecting of probiotic bacteria from traditional food of high-altitude Himalayan region

Bioprospecting of novel probiotic strains from traditional food (Chhurpi) of high-altitude areas of the Himalayan region was undertaken in this study. A group of lactic acid bacteria were isolated from cottage cheese, their cumulative probiotic score was compared, and one potent bacterium was identified as Pediococcus pentosaceus BAC L7. The selected strain synthesized a bacteriocin (pediocin) having molecular weight of 4.178 kDa. Along with thermostability, its stability in presence of acid, trypsin, lysozyme and in simulated gastro-intestinal condition was documented. Production of pediocin was maximum (28,147 AU/ml) at the logarithmic phase of growth. The peptide showed strong antimicrobial effect against Enterococcus faecalis, Salmonella typhi, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella dysenteriae and Candida albicans. The selected strain exhibited strong in-vitro antioxidant activity and was experimentally demonstrated as safe. Thus, the newly explored probiotics will be an effective natural therapeutic against gastroenteritis, a common malady at high altitude.