Screening for antibacterial activity in 72 species of wood-colonizing fungi by the Vibrio fisheri bioluminescence method

Resistance of pathogenic bacteria to antibiotics leads scientists to discover new antibacterial drugs. Ninety samples of wood-colonizing fungi were cultivated on agar plates, and their extracts tested for antibacterial activity using the Vibrio fischeri bioluminescence test. Two fungi species, Serpula lacrymans and Nectria vilior, were found to be a potential new source of thermostable antibiotics. Vibrio fischeri bioluminescence test was found to be a useful method for antibacterial activity screening from the samples of natural origin.     

五种药用石斛内生真菌抑制HIV-1整合酶活性研究

目的 评价5种药用石斛内生真菌发酵产物抑制HIV-1整合酶的活性.方法 将分离自石斛的202株内生真菌提取物共404个采用高通量ELISA法评价其抑制HIV-l整合酶活性;对抑制活性大于100％的样品进行量效关系考察并进行体外抑制肿瘤细胞活性筛选.结果 筛选得到19个对HIV-l整合酶抑制活性大于80％的样品,其中样品5119F、5297F、5097F、5140J和5211F的抑制率分别达到117.96％、113.53％、108.62％、103.74％和109.02％,其对应的IC50值分别为0.02024、0.003125、0.00862、0.01007 和 0.01192 mg/ml.结论石斛属药用植物内生真菌是一个潜在的、丰富的用于筛选HIV-1整合酶抑制剂的资源库,值得进一步研究和开发.     

Evaluation of antibacterial,antifungal and modulatory activity of methanol and ethanol extracts of Padina sanctae-crucis

Background

Multi-resistantmicroorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida tropicalis e Candida krusei are the main causes of microbial infections. Padina sanctae-crucis is a seaweed often used to check the contamination of ecosystems by materials such as heavy metals, but studies of the antimicrobial activity of the same seaweed were not found.

Methods

The tests for the minimum inhibitory concentration and modulation of microbial resistance, with the use of ethanolic and methanolic extracts of Padina Sanctae-cruces combined with drugs of the class of aminoglycosides and antifungal were used to evaluate the activity against the cited microorganisms.

Results

Was observed a modulation of antibiotic activity between the natural products and the E. coli and S. aureus strains, indicating a synergism and antagonism respectively.

Conclusions

The results showed a moderate modulatory effect against some microorganisms studied.     

Larvicidal efficacy of five cucurbitaceous plant leaf extracts against mosquito species

Larvicidal activity of crude hexane, ethyl acetate, petroleum ether, acetone, and methanol extracts of the leaf of five species of cucurbitaceous plants, Citrullus colocynthis, Coccinia indica, Cucumis sativus, Momordica charantia, and Trichosanthes anguina, were tested against the early fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus (Say) (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in petroleum ether extract of C. colocynthis, methanol extracts of C. indica, C. sativus, M. charantia, and acetone extract of T. anguina against the larvae of A. aegypti (LC₅₀ = 74.57, 309.46, 492.73, 199.14, and 554.20 ppm) and against C. quinquefasciatus (LC₅₀ = 88.24, 377.69, 623.80, 207.61, and 842.34 ppm), respectively. The petroleum ether extract of C. colocynthis and methanol extract of M. charantia were more effective than the other extracts. This is an ideal eco-friendly approach for the control of the dengue vector, A. aegypti, and the lymphatic filariasis vector, C. quinquefasciatus.     

Evaluation of the immunostimulatory activity of Ziziphora tenuior extracts

Macrophages have an important role in host defense against fungal infections such as candidiasis. Active components such as polysaccharides, lectins, proteins, and peptides present in plants have been shown to stimulate the immune system. The aim of this study was to investigate the immunostimulatory effects of water, ethanol, and acetone extracts of Ziziphora tenuior (Z. tenuior) on murine peritoneal mactophages in vitro. Murine peritoneal macrophages were treated with different concentrations of Z. tenuior extracts. The viability of macrophages and nitric oxide production were evaluated using 3-(4, 5-dimethylthiaozle-2-yl)-2, 5-diphenyle-tetra zolium bromide (MTT) assay and Griess method, respectively. In addition, the reactive oxygen species (ROS) production and fungicidal activity were evaluated by nitrobiue tetrazolium (NBT) assay and killing method, respectively. A significant increase in macrophage activity was observed with water extract of Z. tenuior (P < 0.05). Moreover, this extract showed a significant inducing effect on the levels of ROS and a strong fungicidal activity in treated macrophages at concentrations of 10 and 20 mg/ml (P < 0.05). In conclusion, Z. tenuior extract demonstrated significant immunostimulatory activity using MTT, NBT, and killing assays on Candida albicans. To clarify the exact machanisms of this activity, more studies should be performed with isolated immunostimulatory components.     

Evaluation of proteolytic activity to differentiate some dematiaceous fungi.

A total of 123 isolates of Cladosporium spp., Exophiala spp., Fonsecaea spp., Lecythophora hoffmannii, Phaeoannellomyces werneckii, Phialophora spp., Wangiella dermatitidis, and Xylohypha bantiana were tested for proteolytic activity by using 26 different formulations of gelatin, milk, casein, and Loeffler media. Other physiological properties examined included hydrolysis of tyrosine and xanthine, sodium nitrate utilization in Czapek Dox agar, and thermotolerance. Isolates of Exophiala jeanselmei, Fonsecaea compacta, Fonsecaea pedrosoi, W. dermatitidis, and X. bantiana lacked proteolytic activity. Proteolytic activity was variable among the remaining species, depending on the type of medium used. Thermotolerance had value in distinguishing some taxa.     

Comparative IgE responses to extracts of five species of house dust mite, using Western blotting

IgE responses towards extracts of Demotopkagoides pteronysssinus, D. farinae, D. microceras, Euroglyphus maynei and Gymnoglyphus longior have been evaluated with sera from a mite sensitive population and the international reference pool of sera, NIBSC 82/528, using Western blotting. Using mite body and faecal extracts 21 of 29 mite protein bands responded to by sera were common to all five species of mite. All sera were unique with respect to proteins bound and species recognized. Mite proteins bound by more than 40% of sera included the Group II and FFI main allergens and protein bands 14 (MW 40.4 kD) and 21 (MW 27.8 kD), all of which were found in every mite species studied. The Group I allergen, found in all species, was bound by 29.4% of sera. Similar response profiles between mite species suggest that human specific IgE may bind predominantly to crossreactive determinants on mite allergens.     

Rhizosphere fungi of five plants in Egypt

75 species which belong to 25 genera were collected during this investigation. All of these fungi were previously isolated from Egyptian soils and other sources. The total count and the number of genera and species in the rhizosphere soil of the 5 plants were regularly higher than in non-rhizosphere soil. The composition of the rhizosphere fungus flora was considerably influenced by the type and the age of the plant. The most prevalent fungi in the rhizosphere of the test plants after 45, 90, and 150 days were as follows: in Helianthus annuus, Stachybotrys atra and Aspergillus niger; in Chrysanthemum coronarium, Cladosporium herbarum, A. sydowii and Penicillium funiculosum; in Nigella sativa, Fusarium moniliforme and A. sydowii; in Datura innoxia, A. fumigatus and A. terreus; in Hyoscyamus muticus, C. herbarum and A. sydowii; and in soil, P. funiculosum, A. terreus and A. niger. The counts of total fungi and most of the common fungal species, except in the case of Datura innoxia, reached their maxima after 90 days and sharply declined after 150 days.     

Evaluation of five new plating media for isolation of Salmonella species.

A three-phase study was conducted to compare Hektoen enteric agar (HE), Rambach agar (Ra), SM-ID medium (SM), xylose-lysine-Tergitol 4 agar (XLT4), novobiocin-brilliant green-glycerol-lactose agar (NBGL), and modified semisolid Rappaport-Vassiliadis medium (MSRV) for the recovery of nontyphoid salmonellae from stool specimens. After evaluation of the first two phases, which resulted in the elimination of Ra, SM, and NBGL, 593 consecutive stool samples were investigated by plating them directly and after tetrathionate enrichment at 37 degrees C on HE, XLT4, and MSRV. A total of 82 Salmonella-positive stool specimens were detected (positivity rate, 13.8%). Sensitivities for direct plating and after tetrathionate enrichment were 32.9 and 86.6%, respectively, for XLT4, 63.4 and 100.0%, respectively, for MSRV, and 34.1 and 79.3%, respectively, for HE. Specificities (percentage of morphologically suspicious colonies that were indeed salmonellae) were 100.0 and 99.8%, respectively, for XLT4, 99.0 and 98.8%, respectively, for MSRV, and 67.9 and 75.0%, respectively, for HE. The use of MSRV instead of HE increased the isolation rate of salmonellae by 26.2% (65 versus 82 strains isolated from HE and MSRV, respectively). We conclude that MSRV is the most sensitive medium tested and is a very specific medium for the isolation of nontyphoid salmonellae from stool specimens. However, its semisolid nature is a disadvantage and requires careful handling in the laboratory, especially when salmonellae are present. XLT4 had a sensitivity comparable to that of HE and a nearly 100% specificity and can be regarded as an alternative for the isolation of nontyphoid salmonellae from stool samples.     

Assessment of antibacterial activity of crude leaf and root extracts of Cassia alata against Neisseria gonorrhea

Background

Gonorrhea is a major sexually transmitted disease worldwide and for its control, effective treatment is essential. However as more strains of Neisseria gonorrhoeae continuously develop resistance to several drugs, this strategy obliges scientists to discover newer effective drugs.

Objectives

To ascertain whether crude leaf and root extracts of Cassia alata (Caesalpiniaceae) have antimicrobial activity against clinically resistant Neisseria gonorrhoeae bacteria. To determine and compare the MICs of their ether and methanol extracts.

Materials and methods

Ether and methanol extracts were prepared from the plant parts. 12–375mg/ml of serially diluted ether extracts in DMSO and methanol extracts in water were tested using agar-well diffusion method against Neisseria gonorrhea clinical isolate cultured on MTM agar. MICs were determined from corresponding concentration-response curves. Ceftriaxone was used as positive control, whereas DMSO and water as negative controls.

Results

All the crude extracts showed concentration-dependent Neisseria gonorrhea inhibition. Ether extracts for both leaves and roots gave lower MICs compared to those of methanol. Ether root extract showed the highest potency.

Conclusions

Both the leaf and the root of Cassia alata plant have activity against clinically resistant Neisseria gonorrhoeae; the root having the higher activity. Lipophilic solvent, ether, give more potent antigonorrhoeal extracts. As expected Cassia alata plant in Central Uganda also has antibacterial activity.     

Evaluation of five commercial systems for identification of coagulase-negative staphylococci to species level

Five commercially available systems for identification of coagulase-negative staphylococci to the species level were evaluated using 163 clinical staphylococcal isolates. The conventional method of Kloos and Schleifer served as reference method. The API 20GP system showed the highest rate of agreement with the reference method, correctly identifying 98.8% of the isolates. The Microscan system had an overall rate of agreement of 96.3 %, and Staph-Trac, Sceptor and Staph-Ident rates of 88.8 %, 87.6 % and 84. % respectively.     

苯妥英钠的抑菌活性

背景：苯妥英钠在创面愈合过程中的抑菌作用仍不明确。 目的：通过体外及动物实验观察苯妥英钠在创面愈合过程中是否具有抑菌作用。 方法：①体外实验：采用水解酪蛋白肉汤稀释法检测苯妥英钠的最低抑菌浓度、琼脂扩散法观察1 024 mg/L的苯妥英钠的体外抑菌活性。②动物实验：将30只SD大鼠随机等分为3组,在大鼠背侧脊柱旁设计一2 cm×3 cm矩形创面,分别用10,20 mg/cm²苯妥英钠糊剂或单纯凡士林纱布进行处理,创面均外加凡士林油纱及干纱包扎固定。隔日换药,于第4,8,12,16天进行创面表面细菌定量培养。 结果与结论：①水解酪蛋白肉汤稀释法结果：应用质控菌株、临床菌株进行试验,不同苯妥英钠浓度的试管中均呈现浑浊状态。②琼脂扩散法结果：应用质控菌株进行试验,未发现抑菌圈的形成。③实验动物创面细菌定量培养结果：应用10,20 mg/cm²苯妥英钠糊剂处理的创面细菌定量略低于单纯凡士林纱布处理的创面,但各组之间差异均无显著性意义(P > 0.05)。表明苯妥英钠尚无明确的体外及体内抑菌活性,对创面细菌的清除无明显作用。     

In vitro antiplasmodial and phytochemical study of five Artemisia species from Iran and in vivo activity of two species

The extract from Artemisia annua, containing artemisinin, has been proven active against multidrug resistant Plasmodium falciparum in previous studies. The purpose of this paper was to study five Artemisia species from Iran for their in vitro and in vivo antimalarial property and detection of artemisinin in the active species by chromatographic and spectroscopic methods including nuclear magnetic resonance (NMR) spectroscopy. Dried plants were extracted by 80% ethanol, and total extracts were investigated for antiplasmodial property and artemisinin content by TLC, HPLC, and ¹H-NMR techniques. Two plants (A. annua L. and Artemisia absinthium L.) showed good antiplasmodial activity against multidrug resistant and sensitive strain of P. falciparum. A. absinthium and A. annua at concentrations of 200 mg/kg for 4 days reduced parasitemia in BALB/C mice infected with Plasmodium bergei by 94.28% and 83.28%, respectively, but we could not detect artemisinin in all plants studied in this research. The antiplasmodial property of these two herbs is possibly related to essential oils that present in high amounts in their extracts.     

Evaluation of antibacterial activity of nanostructured poly(1-naphthylamine) and its composites

The present study reports some preliminary investigations on the antibacterial activity of nanostructured poly(1-naphthylamine) (PNA) and its composites with polyvinyl alcohol (PVA) and polyvinylchloride (PVC). The antibacterial activity was evaluated against Escherichia coli and Staphylococcus aureus. The particle size and morphology of PNA and its composites was found to play a significant role in deciding the antimicrobial efficiency. A mechanism of antimicrobial activity has been suggested.     

Antifungal activity of Camellia sinensis crude extracts against four species of Candida and Microsporum persicolor

Objective of the study

Candidiasis and dermatophytoses are benign infections in humans and animals, but they are very dreaded diseases in immunocompromised individuals. These infections become resistant to different treatments which make them more dangerous. In this work, we tried to find a new way for treating them. So we were interested in the antifungal activity of Camellia sinensis (tea); this plant is known to have many health benefits.