Myxobolus cerebralis internal transcribed spacer 1 (ITS-1) sequences support recent spread of the parasite to North America and within Europe

Molecular approaches for resolving relationships among the Myxozoa have relied mainly on small subunit (SSU) ribosomal DNA (rDNA) sequence analysis. This region of the gene is generally used for higher phylogenetic studies, and the conservative nature of this gene may make it inadequate for intraspecific comparisons. Previous intraspecific studies of Myxobolus cerebralis based on molecular analyses reported that the sequence of SSU rDNA and the internal transcribed spacer (ITS) were highly conserved in representatives of the parasite from North America and Europe. Considering that the ITS is usually a more variable region than the SSU, we reanalyzed available sequences on GenBank and obtained sequences from other M. cerebralis representatives from the states of California and West Virginia in the USA and from Germany and Russia. With the exception of 7 base pairs, most of the sequence designated as ITS-1 in GenBank was a highly conserved portion of the rDNA near the 3-prime end of the SSU region. Nonetheless, the additional ITS-1 sequences obtained from the available geographic representatives were well conserved. It is unlikely that we would have observed virtually identical ITS-1 sequences between European and American M. cerebralis samples had it spread naturally over time, particularly when compared to the variation seen between isolates of another myxozoan (Kudoa thyrsites) that has most likely spread naturally. These data further support the hypothesis that the current distribution of M. cerebralis in North America is a result of recent introductions followed by dispersal via anthropogenic means, largely through the stocking of infected trout for sport fishing.     

Inhibition of 5-lipoxygenase and leukotriene C4 synthase in human blood cells by thymoquinone

Black cumin seed, Nigella sativa L., and its oils have traditionally been used for the treatment of asthma and other inflammatory diseases. Thymoquinone (TQ) has been proposed to be one of the major active components of the drug. Since leukotrienes (LTs) are important mediators in asthma and inflammatory processes, the effects of TQ on leukotriene formation were studied in human blood cells. TQ provoked a significant concentration-dependent inhibition of both LTC4 and LTB4 formation from endogenous substrate in human granulocyte suspensions with IC50 values of 1.8 and 2.3 microM, respectively, at 15 min. Major inhibitory effect was on the 5-lipoxygenase activity (IC50 3 microM) as evidenced by suppressed conversion of exogenous arachidonic acid into 5-hydroxy eicosatetraenoic acid (5HETE) in sonicated polymorphonuclear cell suspensions. In addition, TQ induced a significant inhibition of LTC4 synthase activity, with an IC50 of 10 microM, as judged by suppressed transformation of exogenous LTA4 into LTC4. In contrast, the drug was without any inhibitory effect on LTA4 hydrolase activity. When exogenous LTA4 was added to intact or sonicated platelet suspensions preincubated with TQ, a similar inhibition of LTC4 synthase activity was observed as in human granulocyte suspensions. The unselective protein kinase inhibitor, staurosporine failed to prevent inhibition of LTC4 synthase activity induced by TQ. The findings demonstrate that TQ potently inhibits the formation of leukotrienes in human blood cells. The inhibitory effect was dose- and time-dependent and was exerted on both 5-lipoxygenase and LTC4 synthase activity.     

Essential oil of Daucus glaber Forssk

The composition of the essential oil of the fruits, leaves and stems of Daucus glaber Forssk has been studied by GC/MS. It was found that, the essential oil of the fruits consists of monoterpene hydrocarbons (limonene and sylvestrene are the majors) and phenylpropanoids (elemicin is the major). Sylvestrene has never been reported before in the essential oil of any Daucus species. The study of the essential oil of the leaves revealed the presence of monoterpene hydrocarbons; limonene and gamma-terpinene are the majors and a small amount of sylvestrene. The essential oil of stems consists of monoterpene hydrocarbons (gamma-terpinene is the major), terpene alcohols (mainly 4-terpineol) and phenylpropanoids (myristicin and elemicin are the majors). It is interesting that, the essential oil of the fruits is free from any oxygenated terpenes while that of the stems is free from limonene and sylvestrene which are present in the essential oil of the fruits and leaves in fairly large amounts The essential oil of the fruits, leaves and stems shows broad antimicrobial activities against both gram positive and gram negative bacteria. In addition, the volatile oil of the stem, particularly, show activities against Candida albicans (yeast). Also, the prepared oils have variable cytotoxic activities with LC50 21.52, 36.01 and 42.34 microg/ml, respectively.     

Phenyl thiazolyl urea and carbamate derivatives as new inhibitors of bacterial cell-wall biosynthesis

Over 50 phenyl thiazolyl urea and carbamate derivatives were synthesized for evaluation as new inhibitors of bacterial cell-wall biosynthesis. Many of them demonstrated good activity against MurA and MurB and gram-positive bacteria including MRSA, VRE and PRSP. 3,4-Difluorophenyl 5-cyanothiazolylurea (3p) with clog P of 2.64 demonstrated antibacterial activity against both gram-positive and gram-negative bacteria.     

Activity of some hepatic enzymes in schistosomiasis and concomitant alteration of arylsulfatase B

The levels of arylsulfatases A and B, alpha-amylase, aspartate transcarbamylase, and gamma-glutamyl transpeptidase were investigated during the infection of mice with schistosoma mansoni. This infection caused a significant (p < 0.001) increase in the activity of hepatic arylsulfatase B (ASB), aspartate transcarbamylases and gamma-glutamyl transpeptidase. A non-significant difference occurred for alpha-amylase (p < 0.3) and arylsulfatase A (p > 0.5) when compared to the control. The specific activity of hepatic ASB was progressively increased with the progression of the Schistosoma-infection. Moreover, the kinetic studies of hepatic ASB in Schistosoma-infection showed that a slight decrease in the value of K(m) and about a 40% increase in V(max) when compared to the control. In addition, the pH optimum of hepatic ASB was altered from 6 to 7 as a result of schistosomiasis. These observations suggest that there are schistosomiasis-associated changes of the catalytic and kinetic properties of hepatic ASB.     

Enzymes of Candida albicans cell-wall lytic system produced by Streptomyces thermodiastaticus

The production of the enzymes of Candida albicans cell-wall lytic system by S. thermodiastaticus was found to be affected by some growth conditions and nutritional factors. The highest lytic activity was obtained after 18 h of incubation at pH 5.5 and an incubation temperature of 50 degrees C. The carbon source influenced the production of the enzymes of the yeast cell wall lytic system. Maximum lytic activity was obtained when Candida albicans cell-wall (1 g/100 ml) was used as the sole carbon source. NaNO3 at 0.1 g/100 ml level was the best nitrogen source for the biosynthesis of the enzymes of the yeast lytic system. From all phosphor sources, microelements, and growth factors tested, KH2PO4 (1 g/l), ZnSO4 (1 mg/l) and Tween 80 (0.1%), respectively were found to favour highest enzymes production of the lytic system. The Candida albicans cell-wall lytic system produced by S. thermodiastaticus mainly contained chitinolytic and proteolytic activities.     

B2-1, a Sec7- and pleckstrin homology domain-containing protein, localizes to the Golgi complex

B2-1 is a human protein that contains both a Sec7 and a pleckstrin homology domain. The yeast Sec7 protein was previously shown to be involved in vesicle formation in the Golgi and endoplasmic reticulum. Recently, several groups have shown that B2-1 and highly similar proteins (e.g., ARNO, ARNO3) have varied cellular functions and subcellular locations. One of these is an association of the B2-1 Sec7 domain with the plasma membrane, binding to the cytoplasmic portion of the integrin beta2 chain (CD18) and is postulated to be involved in inside-out signaling. Other groups have shown that B2-1 and these related proteins are guanine nucleotide-exchange factors that act upon ADP ribosylation factors (ARFs) and are localized to the Golgi or plasma membrane. Here we report the subcellular localization of B2-1 protein. Interestingly, B2-1 does not localize to the plasma membrane but rather associates with a distinct Golgi complex compartment. B2-1's distribution can be disrupted by brefeldin A, a drug that rapidly disrupts the Golgi apparatus by inhibiting ARF activity. Furthermore, transient transfection of GFP-tagged B2-1 shows Golgi complex targeting. Excessive overexpression of transfected B2-1 causes partial Golgi dispersion.     

Protective effects of thymoquinone and desferrioxamine against hepatotoxicity of carbon tetrachloride in mice

The effects of thymoquinone (TQ) and desferrioxamine (DFO) against carbon tetrachloride (CCl4)-induced hepatotoxicity were investigated. A single dose of CCl4 (20 microl/kg, i.p.) induced hepatotoxicity, manifested biochemically by significant elevation of activities of serum enzymes, such as alanine transaminase (ALT, EC: 2.6.1.2) , aspartate transaminase (AST, EC: 2.6.1.1) and lactate dehydrogenase (LDH, EC: 1.1.1.27). Hepatotoxicity was further evidenced by significant decrease of total sulfhydryl (-SH) content, and catalase (EC: 1.11.1.6) activity in hepatic tissues and significant increase in hepatic lipid peroxidation measured as malondialdhyde (MDA). Pretreatment of mice with DFO (200 mg/kg i.p.) 1 h before CCl4 injection or administration of TQ (16 mg/kg/day, p.o.) in drinking water, starting 5 days before CCl4 injection and continuing during the experimental period, ameliorated the hepatotoxicity induced by CCl4, as evidenced by a significant reduction in the elevated levels of serum enzymes as well as a significant decrease in the hepatic MDA content and a significant increase in the total sulfhydryl content 24 h after CCl4 administration. In a separate in vitro assay, TQ and DFO inhibited the non-enzymatic lipid peroxidation of normal mice liver homogenate induced by Fe3+/ascorbate in a dose-dependent manner. These results indicate that TQ and DFO are efficient cytoprotective agents against CCl4-induced hepotoxicity, possibly through inhibition of the production of oxygen free radicals that cause lipid peroxidation.     

Isolation and characterization of two types of actinophage infectingStreptomyces scabies

Two types of actinophages, ϕS and ϕL, were isolated from soil samples by usingStreptomyces scabies, a potato scab pathogen, as indicator strain. The phages were partially characterized according to their physicochemical properties, plaques and particles morphology, and their host range; this varied from narrow (for ϕS) to wide (for ϕL). The adsorption rate constants of the ϕS and ϕL were 3.44 and 3.18 pL/min, and their burst sizes were 1.61 and 3.75 virions per mL, respectively. One-step growth indicated that ϕS and ϕL have a latent period of 1/2 h followed by a rise period of 1/2 h. The temperate character of these phages was tested in other isolates ofStreptomyces. Four of the phages (ϕSS3, ϕSS12, ϕSS13 and ϕSS17) were identified as temperate phages, since they were able to lysogenize SS3, SS12, SS13 and SS17. ϕSS3, ϕSS12 and ϕSS13 were homoimmune, and they were heteroimmune with respect to ϕSS17. The restriction barriers of lysogenic isolates (SS12, SS13 and SS17) interfered with the blockage of plaque formation by phages (ϕSS12, ϕSS13 or ϕSS17) propagated on them, about 75% of lysogenic isolates had restriction systems. The exposure of the lysogenic isolates (SS12, SS13 and SS17) to UV-irradiation prevented the possible restriction barriers of these isolates so that these barriers could be overcome.