Expression of cagA,virB/D Complex and/or vacA Genes in Helicobacter pylori Strains Originating from Patients with Gastric Diseases

In order to better understand pathogenicity of Helicobacter pylori, particularly in the context of its carcinogenic activity, we analysed expression of virulence genes: cagA, virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, virD4) and vacA in strains of the pathogen originating from persons with gastric diseases. The studies were conducted on 42 strains of H. pylori isolated from patients with histological diagnosis of non-atrophic gastritis—NAG (group 1, including subgroup 1 containing cagA⁺ isolates and subgroup 2 containing cagA^- strains), multifocal atrophic gastritis—MAG (group 2) and gastric adenocarcinoma—GC (group 3). Expression of H. pylori genes was studied using microarray technology. In group 1, in all strains of H. pylori cagA⁺ (subgroup 1) high expression of the gene as well as of virB/D was disclosed, accompanied by moderate expression of vacA. In strains of subgroup 2 a moderate expression of vacA was detected. All strains in groups 2 and 3 carried cagA gene but they differed in its expression: a high expression was detected in isolates of group 2 and its hyperexpression in strains of group 3 (hypervirulent strains). In both groups high expression of virB/D and vacA was disclosed. Our results indicate that chronic active gastritis may be induced by both cagA⁺ strains of H. pylori, manifesting high expression of virB/D complex but moderate activity of vacA, and cagA^- strains with moderate expression of vacA gene. On the other hand, in progression of gastric pathology and carcinogenesis linked to H. pylori a significant role was played by hypervirulent strains, manifesting a very high expression of cagA and high activity of virB/D and vacA genes.     

In vitro anti-herpetic activity of an aqueous extract from the plant Phyllanthus orbicularis

The Herpesviridae includes at least eight viral species pathogenic for humans, responsible for a wide variety of clinical symptoms. The lack of an effective vaccine and the moderate to high toxicity of the available synthetic anti-herpes compounds emphasises the need for new inhibitors. Several Phyllanthus genus (Euphorbiaceae) members have been widely used in traditional medicine and their biological properties have been intensely studied. In this study we investigated the in vitro antiviral activity of the Cuban-endemic plant Phyllanthus orbicularis H.B.K. against Herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) reference strains and clinical isolates with different sensitivities to acyclovir. The inhibitory activity on Human cytomegalovirus (HCMV) replication was also investigated. The selectivity indexes (SI) found for Ph. orbicularis aqueous extract ranged from 8.7 to 37.6. Studies on the antiviral mechanisms involved revealed that the drug acted at early stages of herpesvirus replication, possibly by producing a virucidal effect, although further inhibition of intracellular replication events could not be ruled out.     

Synthesis,evaluation and molecular docking studies of amino acid derived N-glycoconjugates as antibacterial agents

Six amino acid derived N-glycoconjugates of d-glucose were synthesized, characterized and tested for antibacterial activity against G(+)ve (Bacillus cereus) as well as G(−)ve (Escherichia coli and Klebsiella pneumoniae) bacterial strains. All the tested compounds exhibited moderate to good antibacterial activity against these bacterial strains. The results were compared with the antibacterial activity of standard drug Chloramphenicol, where results of A5 (Tryptophan derived glycoconjugates) against E. coli and A4 (Isoleucine derived glycoconjugates) against K. pneumoniae bacterial strains are comparable with the standard drug molecule. In silico docking studies were also performed in order to understand the mode of action and binding interactions of these molecules. The docking studies revealed that, occupation of compound A5 at the ATP binding site of subunit GyrB (DNA gyrase, PDB ID: 3TTZ) via hydrophobic and hydrogen bonding interactions may be the reason for its significant in vitro antibacterial activity.     

Antibacterial activity of constituents from Salvia buchananii Hedge (Lamiaceae)

The dichloromethane extract obtained from the aerial parts of Salvia buchananii Hedge was investigated for its antimicrobial properties following a bioassay-oriented fractionation approach. The extract displayed a clear inhibitory activity against several Gram-positive multidrug-resistant clinical strains including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Enterococcus faecium and Enterococcus faecalis. No activity was observed on Gram-negative strains and on Candida species. Phytochemical investigation of this extract led to the isolation of three new clerodane diterpenes (5, 6 and 8) and eight known clerodane diterpenes (1-4, 7, 9-11) as well as ursolic (UA) and oleanolic (OA) acids. Their structures were established by extensive 1D, 2D NMR and HR-MS spectroscopic methods. The mixture UA/OA manifested a broad and powerful activity on several Gram-positive species, while diterpenes 3, 6, 8 and 9 showed moderate inhibitory activity on the Enterococcus species.     

Chemical Constituents and Antimicrobial Activity of Indian Green Leafy Vegetable Cardiospermum halicacabum

The present study was carried out to analyze chemical constituents and antibacterial activity of ethanolic leaf extract of Cardiospermum halicacabum (ECH). The FT-IR spectrum confirmed the presence of alcohols, phenols, alkanes, alkynes, aliphatic ester and flavonoids in ECH. The GC–MS analysis revealed that ECH contained about twenty four compounds. The major chemical compounds identified were cyclohexane-1, 4, 5-triol-3-one-1-carboxylic acid, benzene acetic acid, caryophyllene, phytol and neophytadiene. The ECH was screened for its antibacterial activity against different bacterial strains and anti fungal activity against Candida albicans by agar well diffusion and minimum inhibitory concentration (MIC) assay. ECH exhibited antibacterial and antifungal activity. All the tested bacterial strains showed MIC values ranging from 80 to 125 μg of extract/ml and C. albicans showed 190 μg of extract/ml as a MIC. The maximum activity ECH was observed against human pathogen Staphylococcus aureus followed by Escherichia coli and the fish pathogen Aeromonas hydrophila. ECH exhibited moderate activity against some of the tested multidrug resistant strains.     

Differential strain response in alkaline phosphatase activity to available phosphorus in Microcoleus autumnalis

Toxic, benthic cyanobacterial proliferations have increased in frequency and severity globally and can have negative impacts on aquatic ecosystems, recreation and human health. Microcoleus autumnalis has been associated with numerous animal fatalities and is causing increasing concern. It tends to grow in systems with moderate dissolved inorganic nitrogen and very low dissolved reactive phosphorus. Acquisition of nutrients, particularly phosphorus, from organic sources may explain how M. autumnalis can reach the high biomass in these relatively nutrient deplete environments. In the present study the effect of phosphorus concentration and source on alkaline phosphatase activity was investigated in toxic and non-toxic M. autumnalis strains. Toxic strains exhibited significantly higher alkaline phosphatase activity than non-toxic strains (p < 0.05), and alkaline phosphatase activity increased in all strains under phosphorus-depleted conditions (p < 0.05). Alkaline phosphatase activity was also present in environmental M. autumnalis mats, though at lower levels than in laboratory experiments. The presence of alkaline phosphatase activity indicates that the acquisition of phosphorus from organic phosphorus sources may contribute to the ability of M. autumnalis to grow in systems with low dissolved reactive phosphorus.     

Modification of N-glycosylation modulates the secretion and lipolytic function of apoptosis inhibitor of macrophage (AIM)

The mouse macrophage-derived apoptosis inhibitor of macrophage (AIM), which is incorporated into adipocytes and induces lipolysis by suppressing fatty acid synthase (FAS) activity, possesses three potential N-glycosylation sites. Inactivation of N-glycosylation sites revealed that mouse AIM contains two N-glycans in the first and second scavenger receptor cysteine-rich domains, and that depletion of N-glycans decreased AIM secretion from producing cells. Interestingly, the lack of N-glycans increased AIM lipolytic activity through enhancing AIM incorporation into adipocytes. Although human AIM contains no N-glycan, attachment of N-glycans increased AIM secretion. Thus, the N-glycosylation plays important roles in the secretion and lipolytic function of AIM.

Structured summary of protein interactions

AIMphysically interacts with FAS by anti tag coimmunoprecipitation (View interaction)     

Extracellular DNase activity of Cryptococcus neoformans and Cryptococcus gattii

Extracellular DNase activity was studied in 73 strains of Cryptococcus neoformans and 12 strains of Cryptococcus gattii. DNase activity was measured by DNase agar clearance with and without Methyl Green. All strains tested showed extracellular DNase activity and no significant difference was found betweenC. neoformans and C. gattii strains. DNase production was higher in strains from clinical origin (average radius of 6.2 mm) than among environmental strains (average radius of 2.9 mm). The extracellular enzyme may be detected by DNA substrate PAGE assays and its molecular weight was estimated at 31 kD. These results suggest that extracellular DNase could be considered as a virulence factor involved in C. neoformans–C. gattii species complex pathogenicity.     

Iron Superoxide Dismutase Protects against Chilling Damage in the Cyanobacterium Synechococcus species PCC7942

A strain of Synechococcus sp. PCC7942 lacking functional Fe superoxide dismutase (SOD), designated sodB⁻, was characterized by its growth rate, photosynthetic pigments, inhibition of photosynthetic electron transport activity, and total SOD activity at 0°C, 10°C, 17°C, and 27°C in moderate light. At 27°C, the sodB⁻ and wild-type strains had similar growth rates, chlorophyll and carotenoid contents, and cyclic photosynthetic electron transport activity. The sodB⁻ strain was more sensitive to chilling stress at 17°C than the wild type, indicating a role for FeSOD in protection against photooxidative damage during moderate chilling in light. However, both the wild-type and sodB⁻ strains exhibited similar chilling damage at 0°C and 10°C, indicating that the FeSOD does not provide protection against severe chilling stress in light. Total SOD activity was lower in the sodB⁻ strain than in the wild type at 17°C and 27°C. Total SOD activity decreased with decreasing temperature in both strains but more so in the wild type. Total SOD activity was equal in the two strains when assayed at 0°C.     

Screening and molecular characterization of Serratia marcescens VITSD2: A strain producing optimum serratiopeptidase

The current work was attempted to isolate and characterize the serratiopeptidase producing Serratia sp. Among the 10 bacterial isolates 7 strains were identified as Serratia sp. Out of 7 strains one showed potent proteolytic activity and selected for further studies. Based on the morphological, biochemical and molecular characterization, the potent isolate （RH03） was identified as Serratia marcescens （GenBank accession number： KC961637） and the strain was designated as Serratia marcescens VITSD2. The production of serratiopeptidase was carried out in trypticase soya broth and the enzyme was partially purified using ammonium sulfate precipitation and dialysis. The specific activity was determined by casein hydrolysis assay and was found to be 12.00, 21.33, and 25.40 units/rag for crude, precipitated and dialysed samples. The molecular weight of the protease was determined by SDS-PAGE and it was found to be 50 kDa. The antibacterial activity of the produced serratiopeptidase showed moderate activity against Pseudomonas aeruginosa MTCC No. 4676 （12 mm） and Escherichia coli MTCC No. 1588 （15 mm）.     

Antibacterial Effects of Glycyrrhetinic Acid and Its Derivatives on Staphylococcus aureus

Staphylococcus aureus is a major pathogen in humans and causes serious problems due to antibiotic resistance. We investigated the antimicrobial effect of glycyrrhetinic acid (GRA) and its derivatives against 50 clinical S. aureus strains, including 18 methicillin-resistant strains. The minimum inhibitory concentrations (MICs) of GRA, dipotassium glycyrrhizate, disodium succinoyl glycyrrhetinate (GR-SU), stearyl glycyrrhetinate and glycyrrhetinyl stearate were evaluated against various S. aureus strains. Additionally, we investigated the bactericidal effects of GRA and GR-SU against two specific S. aureus strains. DNA microarray analysis was also performed to clarify the mechanism underlying the antibacterial activity of GR-SU. We detected the antimicrobial activities of five agents against S. aureus strains. GRA and GR-SU showed strong antibacterial activities compared to the other three agents tested. At a higher concentration (above 2x MIC), GRA and GR-SU showed bactericidal activity, whereas at a concentration of 1x MIC, they showed a bacteriostatic effect. Additionally, GRA and GR-SU exhibited a synergistic effect with gentamicin. The expression of a large number of genes (including transporters) and metabolic factors (carbohydrates and amino acids) was altered by the addition of GR-SU, suggesting that the inhibition of these metabolic processes may influence the degree of the requirement for carbohydrates or amino acids. In fact, the requirement for carbohydrates or amino acids was increased in the presence of either GRA or GR-SU. GRA and GR-SU exhibited strong antibacterial activity against several S. aureus strains, including MRSA. This activity may be partly due to the inhibition of several pathways involved in carbohydrate and amino acid metabolism.     

Biofilm-Forming Abilities of Listeria monocytogenes Serotypes Isolated from Different Sources

A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26%) strains as weak, 27 (27.55%) strains as moderate, and 9 (9.18%) strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015) was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 10³ cells/cm², 33±26× 10³ cells/cm², 5±3× 10³ cells/cm², respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI) analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.     

Synthesis and evaluation of the antiplasmodial activity of novel indeno[2,1-c]quinoline derivatives

With the aim to explore the potentiality of new chemical scaffolds for the design of new antimalarials, a set of new indeno[2,1-c]quinolines bearing different basic heads has been synthesized and tested in vitro against chloroquine sensitive (CQ-S) and chloroquine resistant (CQ-R) strains of Plasmodium falciparum. Most of the synthesized compounds exhibited a moderate antiplasmodial activity, inhibiting the growth of both CQ-S and CQ-R strains of P. falciparum with IC₅₀ ranging from 0.24 to 6.9 μM and with a very low resistance index. The most potent compounds (1.2–1.3-fold the CQ on the W-2 strain) can be considered as promising ‘lead compounds’ to be further optimized to improve efficacy and selectivity against Plasmodia.     

Characterization and differentiation of 59 strains of Moraxella urethralis from clinical specimens

The biochemical characteristics of 59 strains of Moraxella urethralis from clinical specimens, primarily from urine and the female genital tract, were studied. The characteristics included (i) the inability to acidify carbohydrate substrates, (ii) the ability to produce phenylalanine deaminase, (iii) the ability to reduce nitrite, (iv) the lack of urease activity, and (v) the ability of most strains to alkalinize citrate. A means of differentiating M. urethralis from Moraxella osloensis and Moraxella phenylpyruvica was determined.     

Lemairones A and B: Two new antibacterial tetraflavonoids from the leaves of Zanthoxylum lemairei (Rutaceae)

Zanthoxylum lemairei is widely used in African folk medicine for its pharmacological relevance. Chemical investigation of the ethanol extract from the leaves of this plant lead to the isolation of two new tetraflavonoids, lemairones A (1) and B (2), along with three known compounds, lupeol, sitosterol, and sitosterol 3-O-β-d-glucopyranoside. The antibacterial screening of the leaves of this plant, characterization of compounds 1 and 2, and their antibacterial activity are reported for the first time. The isolation of the compounds was performed using different chromatographic methods while their structures were elucidated by spectroscopic techniques including MS and NMR, and by comparison of data with those of similar flavonoids reported in the literature. The isolated compounds and the crude extract were tested against ten Gram negative multi-resistance bacterial strains including clinical isolates using a broth dilution method. The crude ethanol extract showed weak activity against the tested bacteria strains with a minimal inhibitory concentration (MIC) ranging from 512 to 1024 μg/mL. Among the isolated metabolites, only the new tetraflavonoids were tested. Lemairone A displayed weak activity while lemairone B had moderate activity against the resistant Escherichia coli AG100 with MIC values of 128 μg/mL and 64 μg/mL respectively. In addition, both molecules displayed weak activity against Klebsiella pneumoniae KP55 (MIC 128 μg/mL).     

Antimicrobial and Antimycobacterial Activities of Methyl Caffeate Isolated from Solanum torvum Swartz. Fruit

Abstract

Solanum torvum Swartz. (Solanaceae) fruit is traditionally used for the treatment of bacterial and fungal infections. The methanolic extract was subjected to activity guided fractionation by column chromatography over silica gel. The structure of the compound was elucidated using physical and spectroscopic data. The antimicrobial activity was screened using five Gram-positive bacteria, six Gram-negative bacteria, seven clinical isolates and four fungi. Antimycobacterial activity was screened against two Mycobacterium strains. The zone of inhibition by methyl caffeate ranged from 0 to 22 mm. The lowest minimum inhibitory concentration (MIC) values of methyl caffeate were: 50 μg/ml against P. vulgaris, 25 μg/ml against K. pneumoniae (ESBL-3971), 8 μg/ml against M. tuberculosis (H³⁷Rv) and 8 μg/ml against M. tuberculosis (Rif^R). Methyl caffeate showed moderate antimicrobial and prominent antimycobacterial activities. Methyl caffeate can be evaluated further for drug development.     

In vitro evaluation of antibacterial,anticollagenase, and antioxidant activities of hop components (Humulus lupulus) addressing acne vulgaris

Seven naturally derived components from hop plant (Humulus lupulus L.) extracts were tested for evaluation of biological activities affecting acne vulgaris. Five strains, Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, Kocuria rhizophila and, Staphylococcus pyogenes, were selected as the main acne-causing bacteria. Hop extracts xanthohumol and the lupulones showed strong inhibitory activities against all of the strains. Although hydrogenated derivatives did not show the same level of activity, naturally occurring xanthohumol, humulones, and lupulones all showed moderate to strong anticollagenase inhibitory activities. Antioxidant capacity was also evaluated with seven different methods based on different reactive oxygen species. Xanthohumol showed the highest activity in total oxygen radical absorbance capacity as well as singlet oxygen absorbance capacity.     

Study of antimicrobial activity and root symbionts of Hemionitis arifolia

Antibacterial and antifungal activity of crude extract, alcoholic extract and extracted phenol from various parts of tropical pteridophyta, Hemionitis arifolia were tested by agar diffusion and tube dilution assay. Both the crude and alcoholic extracts of vegetative and reproductive leaves of H. arifolia showed considerable antibacterial activity against Gram negative test strain of Escherichia coli (MTCC-739). Extract from reproductive leaves also showed moderate antibacterial activity against Bacillus subtilis (MTCC-441) (Gram positive test strain) but didn’t show any antifungal activity against Candida albicans (MTCC-7353). Mycorrhizal and other symbiotic association with the root system of H. arifolia was studied and it is revealed that a number of mycorrhizal strains were present in both vegetative and reproductive form. Presence of Dark Septate Endophytic Fungi (DSF) was also detected.     

Antimalarial activity of 10-alkyl/aryl esters and -aminoethylethers of artemisinin

A series of n-alkyl/aryl esters were synthesized and their in vitro antiplasmodial activity was measured alongside that of previously synthesized aminoethylethers of artemisinin ozonides against various strains of Plasmodium falciparum. The cytotoxicity against human cell lines was also assessed. The esters were synthesized in a one-step reaction by derivatization on carbon C-10 of dihydroartemisinin. Both classes were active against both the 3D7 and K1 strains of P. falciparum, with all compounds being significantly more potent than artemether against both strains. The majority of compounds possessed potency either comparable or more than artesunate with a high degree of selectivity towards the parasitic cells. The 10α-n-propyl 11 and 10α-benzyl 18 esters were the most potent of all synthesized ozonides, possessing a moderate (∼3-fold) and significant (22- and 12-fold, respectively) potency increases against the 3D7 and K1 strains, respectively, in comparison with artesunate.     

Synthesis and evaluation of biological activity for dual-acting antibiotics on the basis of azithromycin and glycopeptides

One of the promising directions of the combined approach is the design of dual-acting antibiotics – heterodimeric structures on the basis of antimicrobial agents of different classes. In this study a novel series of azithromycin-glycopeptide conjugates were designed and synthesized. The structures of the obtained compounds were confirmed using NMR spectroscopy and mass spectrometry data including MS/MS analysis. All novel hybrid antibiotics were found to be either as active as azithromycin and vancomycin against Gram-positive bacterial strains or have superior activity in comparison with their parent antibiotics. One compound, eremomycin-azithromycin conjugate 16, demonstrated moderate activity against Enterococcus faecium and Enterococcus faecalis strains resistant to vancomycin, and equal to vancomycin’s activity for the treatment of mice with Staphylococcus aureus sepsis.