The antimicrobial activities of chloroform, acetone and two different concentrations of methanol extracts of Ocimum basilicum L. were studied. These extracts were tested in vitro against 10 bacteria and 4 yeasts strains by the disc diffusion method. The results indicated that the methanol extracts of O. basilucum exhibited the antimicrobial activity against tested microorganisms. While the chloroform and acetone extracts had no effect, the methanol extracts showed inhibition zones against strains of Pseudomonas aeruginosa, Shigella sp., Listeria monocytogenes, Staphylococcus aureus and two different strains of Escherichia coli. The cells of microorganisms, which were treated and untreated with plant extracts, were observed by using the scanning electron microscope. It was observed that the treated cells were damaged.

Up to now an increasing number of antibiotic-resistant bacteria have been reported and thus new natural therapeutic agents are needed in order to eradicate these pathogens. Through the discovery of plants such as Crataegus tanacetifolia (Lam.) Pers that have antimicrobial activity, it will be possible to discover new natural drugs serving as chemotherapeutic agents for the treatment of nosocomial pathogens and take these antibiotic-resistant bacteria under control. The objective of the present study was to determine antimicrobial activity and the activity mechanism of C. tanacetifolia plant extract. The leaves of C. tanacetifolia, which is an endemic plant, were extracted using methanol and tested against 10 bacterial and 4 yeast strains by using a drop method. It was observed that the plant extract had antibacterial effects on Bacillus subtilis, Shigella, Staphylococcus aureus, and Listeria monocytogenes among the microorganisms that were tested. Minimum inhibitory concentration (MIC) results obtained at the end of an incubation of 24 h were found to be > or =6.16 mg ml(-1) for B. subtilis, < 394 mg ml(-1) for Shigella, and > or =3.08 mg ml(-1) for L. monocytogenes and S. aureus and minimum bactericidal concentration (MBC) were found as > or =24.63 mg ml(-1) for B. subtilis, > or =394 mg ml(-1) for Shigella, > or =6.16 mg ml(-1) for L. monocytogenes, and > or =98.5 mg ml(-1) for S. aureus. According to the MBC results, it was found that the plant extract had bactericidal effects and in order to explain the activity mechanism and cell deformation of bacterial strains treated with plant extract, the scanning electron microscopy (SEM) was used. The results of SEM showed that the treated cells appeared shrunken and there was degradation of the cell walls. This study, in which the antibacterial effect of C. tanacetifolia was demonstrated, will be a base for further investigations on advanced purification and effect mechanism of action of its active compounds.

The antimicrobial activities of chloroform, acetone and two different concentrations of methanol extracts of Artemisia dracunculus L. were studied. These extracts were tested against nine bacteria and four yeasts strains by the disc diffusion method. The results indicated that the methanol extract of A. dracunculus is more effective against tested microorganisms than chloroform or acetone extracts. The chloroform and acetone extracts were inhibitory only towards Pseudomonas aeruginosa (ATCC 27853). While the methanol extract that was diluted with 10 ml distilled water showed inhibition zones against Shigella (RSHI), Listeria monocytogenes ATCC 7644, P. aeruginosa (ATCC 27853), the methanol extract that was diluted with 5 ml distilled water showed inhibition zones against two different strains of Escherichia coli (RSHI, ATCC 25922), Shigella (RSHI), L. monocytogenes (ATCC 7644), and P. aeruginosa ATCC 27853. The cells of microorganisms treated with plant extracts and normal microorganism cells were observed by scanning electron microscope. It was apparent that cells are damaged after treatment with A. dracunculus.

ABSTRACT:Loxoscelism is caused by envenomation by spiders that belong to the Loxosceles genus. In loxoscelism, a local necrotic lesion appears and, in many cases, loxoscelism or necrotic araneism is considered a serious public health problem. There is no diagnostic test available to help the physician make a diagnostic or therapeutic decision. Here, we report the case of a severe dermonecrotic araneism (loxoscelism) in Turkey probably due to the bite of Loxosceles rufescens. There was little erythema at the beginning, followed by severe necrosis after 20 days, and skin grafting was needed although the case was treated.

ABSTRACT:Since the number of microorganisms that are resistant to antibiotics has been increasing steadily, the need for combating these pathogens requires new pharmaceutical agents. To produce these substances, new models have been developed in recent decades. In our study, the venom of Agelena labyrinthica (Clerck, 1757) (Araneae: Agelenidae) was tested against ten bacterial strains, specifically, testing 1/100, 1/10 and 1/1 fractions of diluted venom against these bacteria. While the 1/100 dilution was successful in only one of ten bacterial strains, the 1/10 and the 1/1 were effective on six of ten bacterial strains. The most effective results, among these three different concentrations, were observed on Bacillus subtilis. The other five strains that were also sensitive to the dilutions showed similar inhibition zones. Morphological alterations on bacterial cells and comparison with normal cells were accomplished by scanning electron microscopy (SEM). The venom-treated cells, due to their loss of cytoplasm, shrank and presented cell wall depression.

A 69-year-old woman was awakened with redness and swelling of the left upper eyelid a few days before her presentation. She also noticed a dead spider on her bed. Ophthalmic examination revealed severe left periorbital hyperemia, edema and a wide necrotic area on the upper eyelid. Systemic condition of the patient was well. She was hospitalized with the diagnosis of necrotic arachnidism of the left upper eyelid. Systemic corticosteroid and antibiotic treatment was commenced. No surgical intervention was carried out. A week later, whole upper eyelid was covered with a black eschar. This black eschar shrank with time, and it detached completely within 8 weeks and the lesion healed without a disfiguring scar. Meanwhile, the offending spider was identified as Loxosceles rufescens. Although rare, eyelid may be a biting site for Loxosceles spiders and a favorable result may be obtained with conservative management.

The histology and ultrastructure of venom glands in the scorpionEuscorpius mingrelicus (Kessler, 1874) are described and illustrated in the current study for the first time by employing light microscopy and transmission electron microscopy (TEM). The venom apparatus is composed of a pair of venom glands and a stinger, both situated in the last segment of the metasoma. The venom glands are completely separate but similar. The two glands are segregated within the telson by striated muscle bundles, and their outer surfaces are surrounded by a cuticle. An internal layer constitutes the secretory epithelium. This epithelium is made up of simple columnar cells. The nucleus and organelles involved in cellular synthetic activity are situated basally. In the apical portion, near the gland lumen, there are many secretory granules of different sizes, shapes and electron densities. KEY WORDS:Euscorpius mingrelicus, scorpion, telson, venom gland, histology, ultrastructure. CONFLICTS OF INTEREST:There is no conflict. CORRESPONDENCE TO:MEHLIKA BENLI, Department of Biology, Faculty of Science, Ankara University, Ankara, Turkey. Fax: +903122232395. Email: mehlikabenli_76@hotmail.com. CHARACTERIZATION. J. Venom. Anim. Toxins incl. Trop. Dis., 2008, 14, 3, p. 467 N. Yigit and M. Benli THE VENOM GLAND OF THE SCORPION SPECIES Euscorpius mingrelicus (SCORPIONES: EUSCORPIIDAE): MORPHOLOGICAL AND ULTRASTRUCTURAL INTRODUCTIONScorpions have long been of interest to humans, primarily because of their ability to give painful and sometimes life-threatening stings. These animals are also an important and beneficial component of many ecosystems and they are one of the oldest known terrestrial arthropods. Scorpions present an elongated body. The abdomen consists of 12 distinct segments and the last five segments of abdomen form the metasoma that is commonly called as a tail. The telson, situated at the end of the metasoma, is a bulb-shaped structure that contains the venom glands and a sharp, curved stinger to deliver venom. The scorpion venom is used for both prey capture and defense. It is a complex mixture of neurotoxins and other substances; each species has a unique composition. Despite their intimidating reputation, about 30 species worldwide have venom sufficiently potent to be considered dangerous to humans (1).Scorpion venoms are rich sources of bioactive peptides but they contain only some biogenic amines (21). Most scorpion toxins, which are ligand peptides, are described in some literatures. They can be recognized and can interact specifically with ion channels (Na + , K + , Cl -and Ca 2+ ) of excitable or non-excitable cells (1, 6, 16, 20). In scorpion venom, there are also many toxins that present antimicrobial activity against both gram-negative and gram-positive bacteria (3, 13, 19).Venoms or whole tails of scorpions have been used as a traditional Chinese medicine to treat some neurological diseases such as stroke, rheumatism and tetanus for more than 2,000 years. Therefore, it is very interesting to identify th...

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