Inhibition Of Bacterial Growth Research Articles

Basic studies on the influence of hemorrhage on the antimicrobial effect of visible light in a trachea model

Abstract Ventilator-associated pneumoniae (VAP) are a major problem in intensive care units. Previous in vitro experiments revealed that blue or violet luminescent endotracheal tubes are capable of inhibiting bacterial growth and may thus prevent pathogens from entering the lung. However, while these in vitro studies were conducted in a relatively transparent bacterial suspension, subglottic secretions around endotracheal tubes can also contain highly absorbent components, such as blood. To investigate if light has an antimicrobial effect under such conditions, staphylococcal solutions containing various absorbent components were irradiated by blue or violet luminescent endotracheal tubes for up to 24 h in a tracheal model. Light was generated externally by LEDs or lasers and entered the tube via light guides. An antimicrobial effect was observed for blue and violet light, which was, however, inhibited to some extent in the presence of light adsorbing molecules. Under these conditions, violet light had a stronger effect than blue at low absorptions, while at strong absorptions the effects converged, with blue light even exhibiting a slightly stronger impact. Significant differences between lasers and LEDs could not be detected. In our model, inhibition of bacterial growth could be observed even in the presence of light absorbing molecules. Illuminating endotracheal tubes with blue or violet light may thus represent a promising strategy to migration of bacteria from the oropharynx into the trachea and, thereby, possibly decrease the incidence of VAP.

Synthesis, structure and biological evaluation as antibacterial agents of Ru(II)-p-cymene-aryldicyclohexylphosphine complexes

The syntheses of two neutral complexes with formula [Ru(η6-p-cymene)(P(Cy)2Ar)Cl2], where P(Cy)2Ar = dicyclohexylphosphine, Ar = Ph (1) and 4-(N,N-dimethylamino)phenyl (4-dma-ph) (2) were performed. Both complexes were fully characterized by molar conductivity, elemental analysis and spectroscopic methods. The molecular structures of 1 and 2 that were elucidated by single crystal X-ray diffraction show that both structures adopt the pseudo-octahedral geometry characteristic of organoruthenium species. Absorption spectra and electrochemical behavior of the complexes were also evaluated and their results were supported by DFT analysis. Both complexes were active against tested bacterial strains: Gram-positive (Staphylococcus aureus) and three species Gram-negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). 2 shows higher bacterial growth inhibition activity compared to 1, which might be due to its molecular structure that could facilitate the interaction among this complex and the biological environment. These results agreed with the Langmuir monolayer and molecular docking studies. 1 and 2 change the pressure isotherms of 1,2-dioleoyl-sn-glycero-3-phosphatidylglycerol, a phospholipid used as a bacterial membrane model. Molecular Docking studies performed with S. aureus and E. Coli bacteria using the Topoisomerase IV (4URN) and DNA Gyrase as receptor (1KZN), showed that both complexes have potential antimicrobial effects compared to the ciprofloxacin.

Pengaruh Ekstrak Biji Ketapang (Terminalia catappa L.) Terhadap Daya Hambat Pertumbuhan Bakteri Eschericia coli

Diarrheal is a disease that is widely endemic in tropical countries, especially in Indonesia. The bacterium that causes the appearance of diarrheal diseases is Eschericia coli. Plants that have the potential to be a cure for diarrhea are ketapang (Terminalia catappa L.). Ketapang seeds contain tannins, flavonoids, alkaloids, and saponins that can be used as antibacterial. This study aims to identify the effect of ketapang seed extract on the activity of E. coli bacteria. Extraction of ketapang seeds is carried out by the soxhlet extraction method with a solvent mixture of water and ethanol 96%. This research is a laboratory experiment. Bacterial growth inhibition test is carried out by the phytochemical test of ketapang seed extract with the addition of FeCl3 solution showed positive results containing tannin compound indicated by the formation of a blackish-green colored solution. Positive control was carried out with amoxicillin and negative control with 70% ethanol solution. The results of the ANOVA test analysis obtained a significance value of 0.963, interpreted that there was a difference in inhibition power in variations in the concentration of ketapang seed extract with the most effective extract concentration being 0.8%. The higher the concentration of ketapang seed extract, the greater the inhibition against the growth of E. coli bacteria, therefore it can be used as a basic ingredient for anti-diarrhea drugs.

Chitosan-coated miconazole as an effective anti-inflammatory agent for the treatment of postoperative infections in obstetrics and vaginal yeast infection control on in vitro evaluations

People with immune deficiency are at risk of developing infections caused by several bacterial and fungal species. In this work, chitosan-coated miconazole was developed by a simple sol-gel method. Miconazole is considered an effective drug to treat vaginal infection-causing bacteria and fungi. The coating of chitosan with miconazole nitrate showed the highest drug loading efficiency (62.43%) and mean particle size (2 μm). FTIR spectroscopic analysis confirmed the entrapment of miconazole nitrate into chitosan polymer. The antifungal result demonstrated that MN@CS microgel possessed notable anti-Aspergillus fumigatus and Candida albicans activity in lower doses. Antibacterial activity results revealed excellent bacterial growth inhibition of MN@CS microgel towards human skin infectious pathogens Escherichia coli and Staphylococcus aureus. The biocompatibility studies of In vitro cell viability and Artemia salina lethality assay suggested that MN@CS microgel is more biosafe and suitable for human external applications. In the future, it will be an efficient anti-inflammatory agent for the treatment of vaginal infections.

Surface Defect Mediated Interactions of Bacterial Growth Media on Microcrystalline ZnO

Nano- and microscale ZnO exhibits significant potential in biomedical applications as an antibacterial agent. This is attributed to the selective toxicity and growth inhibition for a wide range of both Gram-positive and Gram-negative bacteria as well as for microbial strains resistant to traditional antibiotics. Pursuit of novel bactericidal applications, however, is inhibited by uncertainty surrounding the underlying mechanisms of the observed antimicrobial action. The most common suggested mechanisms include generation of various reactive oxygen species, release of Zn ions and surface-surface interactions between the bacterial cell wall and free crystalline surface of ZnO. Recent work has placed an emphasis on the role of the free crystalline surface in bacterial growth inhibition. Additionally, the cytotoxicity of ZnO particles has long been known to be heavily dependent on environmental conditions, yet detailed descriptions of these phenomena are lacking. Herein we investigate the effects of interactions with both bacteria and the bacterial environments on the physicochemical and optoelectronic properties of the free crystalline surface of ZnO microparticles (MPs). This is done to gain insight into the nature of interactions with the bacterial growth media and the influence such interactions have on bacterial growth inhibition. Hereby, we expose hydrothermally grown ZnO MPs to phosphate-buffered saline (PBS) media both with and without the presence of Newman strain S. aureus bacteria. The surface electronic structure and charge dynamics are probed via both time and energy dependent surface photovoltage (SPV) conducted prior to and following minimum inhibitory concentration assays. We demonstrate significant changes in the characteristic timescales of long-lived processes in the SPV transients after exposure to phosphate-rich environments. We also note that the presence of bacteria has an impact on shorter lived processes and suppresses the effect of media at longer timescales. The SPV spectra point to a significant adsorption of phosphate compounds on the crystalline surface. We also demonstrate changes in the electronic structure as a result of exposure to PBS.

Changes in Intracellular and Extracellular Metabolites of Mixed Lactobacillus Strains Enhance Inhibition of Pathogenic Bacterial Growth and Lipopolysaccharide-Induced Alleviation of RAW264.7 Cellular Inflammation.

It is important to explore whether there are antagonistic and synergistic effects between different strains of Lactobacillus when developing mixed Lactobacillus strain products. In this study, we investigated the antagonistic and symbiotic effects of co-cultured Lactobacillus strains, as well as their amelioratory effects on lipopolysaccharide (LPS)-induced inflammation and oxidative stress in RAW264.7 cells. The Lactobacillus strains tested in this paper showed no antagonism. Co-culture of Lactiplantibacillus plantarum Y44 and L. plantarum AKS-WS9 was found to show inhibiting effects on the growth of Escherichia coli and Staphylococcus aureus. Additionally, the co-cultured Lactiplantibacillus plantarum Y44 and L. plantarum AKS-WS9 relieved inflammation in RAW264.7 cells induced by LPS by inhibiting the activation of NF-κB and P38 signaling pathways and down-regulating the expression of pro-inflammatory cytokines NO, ROS, iNOs and TNF-α. And the co-cultured Lactobacillus strains activated the Nrf2 signaling pathway in the LPS-induced RAW264.7 cells to promote the expression of antioxidant enzymes in response to oxidative stress. There was a difference in intracellular and extracellular metabolites between single or co-cultured Lactobacillus strains, and the co-cultured Lactobacillus strains significantly increased extracellular metabolites 4-chlorobenzaldehyde, psoromic acid, and 2-dodecylbenzenesulfonic acid and intracellular metabolites 9(S)-HODE, pyocyanin, and LysoPA. We inferred that the better antibacterial and anti-inflammatory ability of the co-cultured Lactobacillus strains were related to the changes in the metabolites of the co-cultured Lactobacillus strains. The co-cultured L. plantarum Y44 and L. plantarum AKS-WS9 strains exhibited better anti-inflammatory abilities and had the potential to alleviate the symptoms of inflammatory diseases as mixed probiotics.

Potential protein hydrolysates from the white and purple flower varieties of Orthosiphon aristatus leaves

This study was aimed to extract bioactive peptides from the white and purple flower varieties of Orthosiphon aristatus leaves. The herb is well known for its pharmacological importance, possibly attributed to its plant proteins. Phenol based extraction was used to extract plant proteins, and then hydrolysed by proteolytic enzymes such as trypsin (serine protease) and pepsin (aspartic protease). MS/MS analysis revealed that 145 and 125 proteins were detected from the white and purple flower varieties, respectively. Trypsin hydrolysates were showed to have a higher degree of hydrolysis (24–33%), resulting in higher antioxidant and antibacterial activities. The white flower of trypsin hydrolysates showed a higher radical scavenging activity which could be attributed to its higher content of stress proteins (19%). However, trypsin hydrolysates from the purple flower showed higher ferric reducing power and bacterial growth inhibition. The performance of hydrolysates was better than ampicillin in inhibiting Acinetobacter baumanni and Staphylococcus aureus.

Citrullus colocynthis (L.) Schrad.: A Promising Pharmaceutical Resource for Multiple Diseases.

Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) is widely distributed in the desert areas of the world. The fruit bodies of C. colocynthis are recognized for their wide range of nutraceutical potential, as well as medicinal and pharmaceutical uses. The plant has been reported for various uses, such as asthma, bronchitis, cancer, colic, common cold, cough, diabetes, dysentery, and jaundice. The fruit has been extensively studied for its biological activities, which include insecticide, antitumor, and antidiabetic effects. Numerous bioactive compounds have been reported in its fruit bodies, such as essential oils, fatty acids, glycosides, alkaloids, and flavonoids. Of these, flavonoids or caffeic acid derivatives are the constituents associated with the inhibition of fungal or bacterial growth, whereas eudesmane sesquiterpenes or sesquiterpene lactones are most active against insects, mites, and nematodes. In this review, the scientific evidence for the biological activity of C. colocynthis against insecticide, cytotoxic, and antidiabetic effects is summarized.

Extracellular Production of Glutathione by Recombinant Escherichia coli K-12

The goal of this study was to produce a sufficient amount of glutathione in the fermentation medium without the addition of cysteine. This would simplify and reduce the cost of its purification. In addition to reducing the cost of cysteine, it also avoids the inhibition of bacterial growth by cysteine. The gshA, gshB, and cysE genes of Escherichia coli were cloned under the control of the strong T5 promoter of the pQE-80L plasmid and introduced into an E. coli strain knocked out for the genes encoding γ-glutamyltranspeptidase and the GsiABCD glutathione transporter, which are responsible for the recycling of excreted glutathione. The overexpression of the gshA and gshB genes, genes for γ-glutamylcysteine synthetase and glutathione synthetase, and the cysEV95R D96P gene, a gene for serine acetyltransferase with the V95R D96P mutation that makes it insensitive to cysteine, were effective on glutathione production. Na2S2O3 was a good sulfur source for glutathione production, while the addition of Na2SO4 did not affect the glutathione production. With the addition of 50 mM glutamic acid and 75 mM glycine, but without the addition of cysteine, to the simplified SM1 medium, 4.6 mM and 0.56 mM of the reduced and oxidized glutathione, respectively, were accumulated in the extracellular space after 36 h of batch culture. This can eliminate the need to extract glutathione from the bacterial cells for purification.

Copper and Zinc Metal-Organic Frameworks with Bipyrazole Linkers Display Strong Antibacterial Activity against Both Gram+ and Gram- Bacterial Strains.

Here, we report a new synthetic protocol based on microwave-assisted synthesis (MAS) for the preparation of higher yields of zinc and copper in MOFs based on different bis(pyrazolyl)-tagged ligands ([M(BPZ)]n where M = Zn(II), Cu(II), H2BPZ = 4,4'-bipyrazole, [M(BPZ-NH2)]n where M = Zn(II), Cu(II); H2BPZ-NH2 = 3-amino-4,4'-bipyrazole, and [Mx(Me4BPZPh)] where M = Zn(II), x = 1; Cu(II), x = 2; H2Me4BPZPh = bis-4'-(3',5'-dimethyl)-pyrazolylbenzene) and, for the first time, a detailed study of their antibacterial activity, tested against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, as representative agents of infections. The results show that all MOFs exert a broad-spectrum activity and strong efficiency in bacterial growth inhibition, with a mechanism of action based on the surface contact of MOF particles with bacterial cells through the so-called "chelation effect" and reactive oxygen species (ROS) generation, without a significant release of Zn(II) and Cu(II) ions. In addition, morphological changes were elucidated by using a scanning electron microscope (SEM) and bacterial cell damage was further confirmed by a confocal laser scanning microscopy (CLSM) test.

Risk assessment framework for microplastic in marine environments

Constantly raising microplastic (MP) contamination of water sources poses a direct threat to the gentle balance of the marine environment. This study focuses on a multifactor hazard evaluation of conventional (polyethylene - PE, polypropylene - PP, and polystyrene - PS) and alternative (polyethylene terephthalate with 25 % or 50 % recycled material and polylactic acid) plastics. The risk assessment framework explored included MP abundance, water acidification potential, surface oxidation, fragmentation, and bacterial growth inhibition. Based on MP monitoring campaigns worldwide, we conclude that PE-based plastics are the most abundant MPs in water samples (comprise up to 82 % the MP in those samples). A year-long weathering experiment showed that PS-based and PP-based plastics were oxidized to a higher extent, resulting in the highest water acidification with pH reduction of up to three orders of magnitude. Finally, our laboratory experiments showed that weathered PS was the most fragile plastic during mechanical degradation, while both PP- and PS-based plastic extracts showed a significant growth inhibition toward the marine microorganisms (Bacillus sp. and Pseudoaltermonas sp). Using the examined factors as weighted inputs into our framework, this holistic evaluation of hazards suggest that PP-based plastic products were the most hazardous compared to the other conventional and alternative plastic types.

Antibody-Functionalized Polymer Nanoparticles for Targeted Antibiotic Delivery in Models of Pathogenic Bacteria Infecting Human Macrophages.

The efficacy of antibody-functionalized poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs), prepared by nanoprecipitation, carrying rifampicin (RIF) against planktonic, sessile, and intracellular Staphylococcus aureus and Escherichia coli is reported here. A biotinylated anti-S. aureus polyclonal antibody, which binds to structural antigens of the whole bacterium, was functionalized on the surface of RIF-loaded PLGA-based NPs by using the high-affinity avidin-biotin complex. This general strategy allows the binding of commercially available biotinylated antibodies. Coculture models of S. aureus ATCC 25923 and Escherichia coli S17 were used to demonstrate the preferential selectivity of the antibody-functionalized NPs against the Gram-positive bacterium only. At 0.2 μg/mL, complete S. aureus eradication was observed for the antibody-functionalized RIF-loaded NPs, whereas only a 5-log reduction was observed for the nontargeted RIF-loaded NPs. S. aureus is a commensal facultative pathogen having part of its live cycle intracellularly in both phagocytic and nonphagocytic cells. Those intracellular bacterial persisters, named small colony variants, have been postulated as reservoirs of relapsed episodes of infection and consequent treatment failure. At 0.5 μg/mL, the RIF-loaded NPs reduced in 2-log intracellular S. aureus-infecting human macrophages. The ability of those antibody-functionalized nanoparticles to prevent biofilm formation or to reduce the bacterial burden in already-formed mature biofilms is also reported here using S. aureus and E. coli single and cocultured biofilms. In the prevention of S. aureus biofilm formation, the antibody-functionalized NPs exerted a superior inhibition of bacterial growth (up to 2 logs) compared to the nonfunctionalized ones. This study demonstrates the selectivity of the synthesized immunonanoparticles and their antimicrobial efficacy in different scenarios, including planktonic cultures, sessile conditions, and even against intracellular infective pathogens.

Multi-Functional Chitosan Nanovesicles Loaded with Bioactive Manganese for Potential Wound Healing Applications.

Chronic skin wound is a chronic illness that possesses a risk of infection and sepsis. In particular, infections associated with antibiotic-resistant bacterial strains are challenging to treat. To combat this challenge, a suitable alternative that is complementary to antibiotics is desired for wound healing. In this work, we report multi-functional nanoscale chitosan vesicles loaded with manganese (Chi-Mn) that has potential to serve as a new tool to augment traditional antibiotic treatment for skin wound healing. Chi-Mn showed antioxidant activity increase over time as well as antimicrobial activity against E. coli and P. aeruginosa PA01. The modified motility assay that mimicked a skin wound before bacterial colonization showed inhibition of bacterial growth with Chi-Mn treatment at a low area density of 0.04 µg of Mn per cm2. Furthermore, this study demonstrated the compatibility of Chi-Mn with a commercial antibiotic showing no loss of antimicrobial potency. In vitro cytotoxicity of Chi-Mn was assessed with macrophages and dermal cell lines (J774A.1 and HDF) elucidating biocompatibility at a wide range (2 ppm-256 ppm). A scratch wound assay involving human dermal fibroblast (HDF) cells was performed to assess any negative effect of Chi-Mn on cell migration. Confocal microscopy study confirmed that Chi-Mn tested at the MIC (16 ppm Mn) has no effect on cell migration with respect to control. Overall, this study demonstrated the potential of Chi-Mn nanovesicles for wound healing applications.

Biocompatible Gallium Nanodots against Drug-Resistant Bacterial Pneumonia and Liver Abscess.

Resistant bacterial infection remains a severe public health threat, and conventional antibiotic drugs work poorly in effectively treating infectious diseases. Here, we developed gallium-based nanodots (Ga NDs), consisting of specific disruption of bacterial iron ability, to treat multidrug-resistant (MDR) Gram-negative bacteria-infected diseases. The Ga NDs significantly suppress the proliferation of two typical MDR bacteria strains (P. aeruginosa and ESBL E. coli) compared with clinically used antibacterial drugs, including penicillin and levofloxacin. Ga NDs could also disrupt the biofilms of these two bacterial strains. In P. aeruginosa infected pneumonia and ESBL E. coli infected acute liver abscess models, the Ga NDs enable substantial inhibition of bacterial growth and reduce the organs' inflammation that resulted in significant improvement of survival. Further, the Ga NDs demonstrated excellent biocompatibility and biosafety characteristics. Together, we believe that our gallium containing nanotherapeutics are expected to be developed into promising alternative therapies to combat drug-resistant bacterial infection.

Multidrug-Resistant Strain ExPEC Isolat Asal Puyuh (Coturnix coturnix japonica)

AbstractExtraintestinal Escherichia coli (ExPEC) causes colibacillosis in poultry, including quail. ExPEC is a pathogenic E. coli that causes colibacillosis outside the gastrointestinal tract of poultry, in the form of peritonitis, pericarditis, salpingitis, synovitis, osteomyelitis, septicemia, pneumonitis, nephritis, pleurisy, proventriculitis and ventriculitis. In poultry farming antibiotics are used to promote growth and egg production, prevention and treatment of bacterial infections. Antibiotic resistance is a new problem that arises in poultry farming. In this study, 24 isolates of ExPEC strain from quail were used. These isolates did not differentiate sorbitol in the MacConkey (SMAC) sorbitol test assay. Antibiotic resistance was tested based on the inhibition of bacterial growth on Muller Hinnton Agar (MHA) media. 10 types of antibiotics were used to observe their resistance in all isolates. Resistance to Amikacin (87.5%), Ampicillin (87.5%), Ciprofloxacin (100%), Clindamycin (95.83%), Cefoxacin (25.0%), Doxycycline (87.5%), Erythromycin (100%), Gentamicin (95.83%), Penicillin (95.83%) and Tetracycline (83.3%). The isolates had multidrug-resistance between 3 to 10 types of antibiotics. This study showed that ExPEC isolates from quail were resistant to the type of antibiotics tested, so that the use of antibiotics in quail culture should be limited to reduce and prevent the emergence of new antibiotic resistance. Keyword: Escherichia coli, sorbitol-negative, quail, antibiotics resistance

Inhibition of Bacterial growth, mineral, proximate and vitamin contents of a syrup prepared from Vitex doniana fruits

Inhibition of Bacterial growth, mineral, proximate and vitamin contents of a syrup prepared from Vitex doniana fruits

Electrochemical detection of fluoride ions using 4-aminophenyl boronic acid dimer modified electrode

Fluoride is a widely used component in dental products, offering benefits such as cavity prevention through bacterial growth inhibition. However, excessive fluoride consumption can lead to fluorosis, which causes tooth discoloration and pitting, and in severe cases, skeletal fluorosis with joint pain and stiffness. Therefore, monitoring fluoride levels in dental products and drinking water is essential. In this study, we developed a rapid electrochemical detection method for fluoride ions using a preanodized screen-printed carbon electrode modified with 4-aminophenylboronic acid dimer (SPCE*/APBAD). The preanodization process involved applying a constant potential of +2 V for 5 min to capture APBAD. The resulting APBAD facilitated a chemical reaction between fluoride ions and boronic acid, forming a fluorophenylboronate complex. This complexation reaction enabled the detection of fluoride ions in a wide linear range (5 µM to 30 mM) with a detection limit of 0.3 µM. The detection behaviour of fluoride ion using SPCE*/APBAD has been studied using cyclic voltammetry, potentiometry, Density Functional Theoretical calculations and flow injection analysis. Furthermore, the practical utility of the sensor was validated by successfully detecting fluoride ions in toothpaste and water samples. The developed method offers a rapid and reliable means of monitoring fluoride ion levels for ensuring safe and beneficial use in dental products and drinking water.

Synthesis of Novel Quinazolinone Analogues for Quorum Sensing Inhibition.

As bacteria continue to develop resistance mechanisms against antimicrobials, an alternative method to tackle this global concern must be developed. As the pqs system is the most well-known and responsible for biofilm and pyocyanin production, quinazolinone inhibitors of the pqs system in P. aeruginosa were developed. Molecular docking following a rationalised medicinal chemistry approach was adopted to design these analogues. An analysis of docking data suggested that compound 6b could bind with the key residues in the ligand binding domain of PqsR in a similar fashion to the known antagonist M64. The modification of cyclic groups at the 3-position of the quinazolinone core, the introduction of a halogen at the aromatic core and the modification of the terminal group with aromatic and aliphatic chains were investigated to guide the synthesis of a library of 16 quinazolinone analogues. All quinazolinone analogues were tested in vitro for pqs inhibition, with the most active compounds 6b and 6e being tested for biofilm and growth inhibition in P. aeruginosa (PAO1). Compound 6b displayed the highest pqs inhibitory activity (73.4%, 72.1% and 53.7% at 100, 50 and 25 µM, respectively) with no bacterial growth inhibition. However, compounds 6b and 6e only inhibited biofilm formation by 10% and 5%, respectively.

Immune responses of the Asian onion moth, Acrolepiopsis sapporensis, and their genetic factors from RNA-Seq analysis.

A nonmodel insect, Acrolepiopsis sapporensis, has been analyzed in immune responses. The total hemocytes in the fifth instar larvae were 2.33 × 106 cells/mL. These hemocytes comprised at least five different types and different relative ratios: 47% granulocytes, 26% plasmatocytes, 11% oenocytoid, 8% prohemocytes, and 5% spherulocytes. Upon bacterial challenge, some of the hemocytes exhibited typical hemocyte-spreading behaviors, such as focal adhesion, and filopodial and lamellipodial cytoplasmic extensions. The hemocyte behaviors induced cellular immune responses demonstrated by nodule formation. In addition, the plasma collected from the immune-challenged larvae exhibited humoral immune responses by bacterial growth inhibition along with enhanced phenoloxidase enzyme activity. These cellular and humoral immune responses were further analyzed by determining the immune-associated genes from a transcriptome generated by RNA-Seq. A total of about 12 Gb sequences led to about 218,116 contigs, which were predicted to encode about 46,808 genes. Comparative expression analysis showed 8392 uniquely expressed genes in the immune-challenged larvae. Differentially expressed gene (DEG) analysis among the commonly expressed genes indicated that 782 genes were upregulated and 548 genes were downregulated in the expressions after bacterial challenge. These immune-associated genes included pattern recognition receptors, immune mediation/signaling genes, and various immune effectors. Specifically, the genetic components of the Toll, IMD, and JAK/STAT immune signaling pathways were included in the DEG database. These results demonstrate the immune responses of A. sapporensis larvae and suggest the genes associated with the immune responses in this nonmodel insect.

Hamamelis virginiana L. Leaf Extracts Inhibit the Growth of Antibiotic-Resistant Gram-Positive and Gram-Negative Bacteria.

Virginian witch hazel (WH; Hamamelis virginiana L.; family: Hamamelidaceae) is a North American plant that is used traditionally to treat a variety of ailments, including bacterial infections. Solvents of varying polarity (water, methanol, ethyl acetate, hexane and chloroform) were used to prepare extracts from this plant. Resuspensions of each extract in an aqueous solution were tested for growth-inhibitory activity against a panel of bacteria (including three antibiotic-resistant strains) using agar disc diffusion and broth microdilution assays. The ethyl acetate, hexane and chloroform extracts were completely ineffective. However, the water and methanolic extracts were good inhibitors of E. coli, ESBL E. coli, S. aureus, MRSA, K. pneumoniae and ESBL K. pneumoniae growth, with the methanolic extract generally displaying substantially greater potency than the other extracts. Combining the active extracts with selected conventional antibiotics potentiated the bacterial growth inhibition of some combinations, whilst other combinations remained non-interactive. No synergistic or antagonistic interactions were observed for any WH extracts/antibiotic combinations. Gas chromatography-mass spectrometry analysis of the extracts identified three molecules of interest that may contribute to the activities observed, including phthalane and two 1,3-dioxolane compounds. Putative modes of action of the active WH extracts and these molecules of interest are discussed herein.