Feeding-Induced Changes of Bacteriolytic Activity and the Pattern of Bacteriolytic Compounds in the Stomach and Small Intestine of the Haematophagous Bug Triatoma infestans (Klug, 1834) (Reduviidae, Triatominae)

Intestinal homeostasis mechanisms of the haematophagous triatomines regulate the development of mutualistic symbionts and other gut bacteria. Investigating antimicrobial compounds of these insects, we have determined spectrophotometrically that the bacteriolytic activity is between pH 3 and pH 9 using homogenates of fifth instar Triatoma infestans stomachs and small intestines from unfed bugs and up to 50 days after feeding. The activity against Gram-positive Micrococcus luteus was strongest at pH 4 and pH 7 and was higher in the stomach than in the small intestine. Symbiotic Rhodococcus triatomae were not lysed. Lysis of Gram-negative Escherichia coli showed a maximum at pH 7 in the stomach and at pH 5 in the small intestine. Bacteriolytic activity against both M. luteus and E. coli was reduced 24 h after feeding, then increased, and at 50 days after feeding was strongly reduced. In zymographs, the activity against M. luteus was mainly correlated to proteins of about 16 kDa. At different periods of time after feeding, seven bands of lysis appeared between 15 and 40 kDa and more bands using extracts of the small intestine than those of the stomach. This is the first proof for the synthesis of antibacterial proteins of 22–40 kDa in triatomines.

Antioxidant, Antibacterial and Dyeing Potential of Crude Pigment Extract of Gonatophragmium triuniae and Its Chemical Characterization

Filamentous fungi synthesize natural products as an ecological function. In this study, an interesting indigenous fungus producing orange pigment exogenously was investigated in detail as it possesses additional attributes along with colouring properties. An interesting fungus was isolated from a dicot plant, Maytenus rothiana. After a detailed study, the fungal isolate turned out to be a species of Gonatophragmium belonging to the family Acrospermaceae. Based on the morphological, cultural, and sequence-based phylogenetic analysis, the identity of this fungus was confirmed as Gonatophragmium triuniae. Although this fungus grows moderately, it produces good amounts of pigment on an agar medium. The fermented crude extract isolated from G. triuniae has shown antioxidant activity with an IC50 value of 0.99 mg/mL and antibacterial activity against Gram-positive bacteria (with MIC of 3.91 μg/mL against Bacillus subtilis, and 15.6 μg/mL and 31.25 μg/mL for Staphylococcus aureus and Micrococcus luteus, respectively). Dyeing of cotton fabric mordanted with FeSO4 using crude pigment was found to be satisfactory based on visual observation, suggesting its possible use in the textile industry. The orange pigment was purified from the crude extract by preparative HP-TLC. In addition, UV-Vis, FTIR, HRMS and NMR (1H NMR, 13C NMR), COSY, and DEPT analyses revealed the orange pigment to be “1,2-dimethoxy-3H-phenoxazin-3-one” (C14H11NO4, m/z 257). To our understanding, the present study is the first comprehensive report on Gonatophragmium triuniae as a potential pigment producer, reporting “1,2-dimethoxy-3H-phenoxazin-3-one” as the main pigment from the crude hexane extract. Moreover, this is the first study reporting antioxidant, antibacterial, and dyeing potential of crude extract of G. triuniae, suggesting possible potential applications of pigments and other bioactive secondary metabolites of the G. triuniae in textile and pharmaceutical industry.

Isolation of rare Genera of actinomycetes — antibiotic producers from soils using Aloe Arborescens juice

The search for new antibiotics is an urgent problem due to the spread of resistance to existing antibacterial drugs in pathogenic microorganisms. Actinomycetes are producers of a large number of antibiotics used in medicine. Most antibiotics are isolated from actinomycetes of the Streptomyces genus, while rare genera of actinomycetes can be the producers of new antibiotics.The aim of the study is to investigate the effect of the biological substances complex present in aloe juice on the growth stimulation of rare genera of actinomycetes.Material and methods. Objects: samples of sod-podzolic soil and chernozem. The standard method of sowing soil suspensions on oat agar and Gause medium No. 2 was used to isolate actinomycetes. Chemotaxonomic properties were determined using the methods of ascending thin-layer chromatography on a cellulose layer. The generic identity of cultures was determined using Bergey’s manual and materials comparing the composition of cell walls of actinobacteria. DNA PCR with standard 27f and 1492r primers, as well as Sanger sequencing, were performed to study genosystematic features. Antibiotic activity was determined against the test microorganisms: Staphylococcus aureus ИНА 00985 (FDA 209P), Staphylococcus aureus ИНА 00761 (MRSA), Staphylococcus aureus ИНА 00762 (УФ- 2), Micrococcus luteus ATCC 9341, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Saccharomyces cerevisiae ИНА 01042.Results. A total of 527 actinomycete cultures were isolated from samples of sod-podzolic soil and chernozem with the addition of aloe juice; their phylogenetic position was determined. The dominant actinomycetes in the studied soil samples are the representatives of the genus Streptomyces. Bacteria of the genus Micromonospora take the second place by the number of isolated cultures. Rare genera of actinomycetes have also been identified: Nonomuraea, Streptosporangium, Nocardia, Actinomadura, Actinocorallia, Pseudonocardia, Amycolatopsis, Saccharomonospora, Saccharopolyspora, Promicromonospora, Kribbella. It was determined that the isolated cultures possess antibiotic activity against test microorganisms.Conclusion. It is advisable to use aloe juice after subjecting the leaves to biostimulation to isolate actinomycetes from the soil and identify their biodiversity.

Synthesis and biological evaluation of pyrazole analogues linked with 1,2,3-triazole and 4-thiazolidinone as antimicrobial agents

A new series of 2-[3-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-4-pyrazolyl]-3-aryl-1,3-thiazolan-4-one 5(a-i) have been designed, synthesized and evaluated for their in vitro antibacterial activity against Gram positive bacteria viz. Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p), Micrococcus luteus (IFC 12708) and Gram negative bacteria viz. Proteus vulgaris (ATCC 3851), Salmonella typhimurium (ATCC 14028), Escherichia coli (ATCC 25922) the antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185), Trichophyton mentagrophytes (IFO 40996). Antibacterial evaluation indicates that compounds containing 4-methoxyphenyl 5c, 4-fluorophenyl 5d and 2,5-difluorophenyl 5h groups on thiazolidinone ring showed significant activity equal to that of standard drug. The antifungal evaluation shows that compound 5c is highly active against A. fumigatus, compound 5d and 5h were also active against C. albicans and A. fumigatus.

Polyhydroxyalkanoates-Based Nanoparticles as Essential Oil Carriers

Plant-derived essential oils (EOs) represent a green alternative to conventional antimicrobial agents in food preservation. Due to their volatility and instability, their application is dependent on the development of efficient encapsulation strategies allowing their protection and release control. Encapsulation in Polyhydroxyalkanoate (PHA)-based nanoparticles (NPs) addresses this challenge, providing a biodegradable and biobased material whose delivery properties can be tuned by varying polymer composition. In this work, EO from Mexican oregano was efficiently encapsulated in Polyhydroxybutyrate (PHB) and Poly-3-hydroxybutyrate-co-hydroxyhexanoate (PHB-HHx)-based NPs by solvent evaporation technique achieving high encapsulation efficiency, (>60%) and loading capacity, (about 50%). The obtained NPs displayed a regular distribution with a size range of 150–210 nm. In vitro release studies in food simulant media were fitted with the Korsmeyer–Peppas model, indicating diffusion as the main factor controlling the release. The cumulative release was affected by the polymer composition, possibly related to the more amorphous nature of the copolymer, as confirmed by WAXS and DSC analyses. Both the EO-loaded nanosystems displayed antimicrobial activity against Micrococcus luteus, with PHB-HHx-based NPs being even more effective than the pure EO. The results open the way to the effective exploitation of the developed nanosystems in active packaging.

Plant Growth-promoting and Bio-control Activity of Micrococcus luteus Strain AKAD 3-5 Isolated from the Soybean (Glycine max (L.) Merr.) Rhizosphere

Background: Applications of bioinoculants for improving crop productivity may be an eco-friendly alternative to chemical fertilizers. Rhizosphere or soil-inhabiting beneficial microbes can enhance plant growth and productivity through direct and indirect mechanisms, i.e., phosphate solubilization, nutrient acquisition, phytohormone production, etc. Objective: This study is based on the hypothesis that diseases resistant plants can act as a source of potential microbes that can have good plant growth-promoting traits and bio-control potential. Methods: In this study, we have isolated the rhizobacterial strains (AKAD 2-1, AKAD 2-10, AKAD 3-5, AKAD 3-9) from the rhizosphere of a disease-resistant variety of soybean (JS-20-34) (Glycine max (L.) Merr.). These bacterial strains were further screened for various plant growth-promoting traits (phosphate solubilization, indole acetic acid (IAA), ammonia, biofilm, HCN, Exopolysaccharide (EPS), and enzyme production activity (catalase, cellulase, and chitinase)). Results: Among four, only bacterial strain AKAD 3-5 has shown plant-growth-promoting and biocontrol (98%) activity against Fusarium oxysporum. Morphological, biochemical, and molecular characterization (16S rRNA) revealed that this rhizobacterial isolate AKAD 3-5 closely resembles Micrococcus luteus (Gene bank accession: MH304279). Conclusion: Here, we conclude that this strain can be utilized to promote soybean growth under varied soil stress conditions.

Comparative antimicrobial activity of Cymbopogon citratus essential oil and thiosemicarbazones derived from this oil

Introduction: The presence of microbes in our environment is always a permanent public health problem. In this context, research on natural treatment, less expensive and accessible to fight these microbial germs would be beneficial. Methods: During this work, molecules of thiosemicarbazones due to their numerous biological activities were hemi-synthesized in situ in the essential oil of Cymbopogon citratus in order to evaluate their antimicrobial activities. Results: Analysis of the essential oil extracted by hydrodistillation revealed the presence of 72.91% of citral. Citralthiosemicarbazone (CThio) and citral 4-phenyl-3-thiosemicarbazone (CPthio) were hemi-synthesized in this oil with interesting yields of 83% and 91%, respectively. After purification and confirmation of the structures of these molecules, the three substances were tested on eleven strains of microbes. Determination of the inhibition diameters showed that the activity of the essential oil is best in over 80% of strains. However, the largest diameter of inhibition (26 mm) was noted with CPthio against Salmonella typhi R 30951401. The determination of the minimum inhibitory concentrations showed that the oil remains more active with the smallest value of 0.3125 mg / ml against Micrococcus luteus. The lower value of minimum bactericidal concentrations was also obtained with the essential oil against Enterococcus foecalis ATCC 29212. Conclusion: The essential oil of C. citratus remains more active in the majority cases. It could be a great alternative in the fight against bacteria, and the advantage is that it remains a natural substance.

Identification of Pathogenic Microbes in Tools of Beauty Salon in Jeddah City

Beauty salons may draw in customers with glamour; however, they could also be considered a major health issue. They can cause the spread of bacterial and fungal infections. The purpose of this research was to identify pathogenic microbes from beauty salon tools. Microorganisms from contaminated salon tools and cosmetic products were isolated using various selective media. Microbial isolates were identified based on their molecular and biochemical characteristics. The most common bacterial species isolated were Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus equorum, Microbacterium spp., Bacillus siamensis, Bacillus subtilis, Sphingomonas aeria, Macrococcus spp., Microbacterium oxydans, Brachybacterium spp., Micrococcus luteus, and Brachybacterium nesterenkovii. Fungal isolates included Penicillium spp., Aspergillus niger, Purpureocillium lilacium, and Aspergillus flavus. Overall, Staphylococcus spp. and A. niger were the most common organisms isolated from the samples. The presence of potential pathogens indicates that the tools used in salons have not been adequately sterilized and the high risk of diseases spread.

Saccharobisindole, Neoasterric Methyl Ester, and 7-Chloro-4(1H)-quinolone: Three New Compounds Isolated from the Marine Bacterium Saccharomonospora sp.

Analysis of the chemical components from the culture broth of the marine bacterium Saccharomonospora sp. CNQ-490 has yielded three novel compounds: saccharobisindole (1), neoasterric methyl ester (2), and 7-chloro-4(1H)-quinolone (3), in addition to acremonidine E (4), pinselin (5), penicitrinon A (6), and penicitrinon E (7). The chemical structures of the three novel compounds were elucidated by the interpretation of 1D, 2D nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS) data. Compound 2 generated weak inhibition activity against Bacillus subtilis KCTC2441 and Staphylococcus aureus KCTC1927 at concentrations of 32 μg/mL and 64 μg/mL, respectively, whereas compounds 1 and 3 did not have any observable effects. In addition, compound 2 displayed weak anti-quorum sensing (QS) effects against S. aureus KCTC1927 and Micrococcus luteus SCO560.

Transcriptome features of trained immunity in Drosophila

Immune memory is an ability of organisms to potentiate immune responses at secondary infection. Current studies have revealed that innate immunity, as well as adaptive immunity, exhibits the memory character called "trained immunity". Although it is suggested that epigenetic reprogramming plays important roles in trained immunity, its underlying mechanism is not fully understood, especially on the individual level. Here we established experimental systems for detecting trained immunity in Drosophila melanogaster. Namely, training infection with low-pathogenic bacteria enhanced the survival rate of the flies at subsequent challenge infection with high-pathogenic bacteria. We found that among low-pathogenic bacteria, Micrococcus luteus (Ml) and Salmonella typhimurium (St) mediated apparent training effects in fly, but seemed to act through different ways. Ml left training effects even after its removal from flies, while living St persisted inside flies for a long time. Our RNA-Seq analysis revealed that Ml-training enhanced the expression of immune-related genes during the challenge infection, but did not do so without challenge infection. In contrast, St-training maintained high expression of the immune-related genes with or without challenge. These results suggest that training effects with Ml and St were due to memory and persistence of immune responses, respectively. Furthermore, we searched the factor involved in Ml-training and identified a candidate, Ada2b, which is a component of the histone modification complex. We found that the Ada2b RNAi and mutant flies showed dampened enhancement of survival rates after Ml-training. These results suggest that Ada2b is involved in the Drosophila trained immunity.