Eicosanoids in insect immunity: bacterial infection stimulates hemocytic phospholipase A2 activity in tobacco hornworms

Intracellular phospholipase A(2) (PLA(2)) is responsible for releasing arachidonic acid from cellular phospholipids, and is thought to be the first step in eicosanoid biosynthesis. Intracellular PLA(2)s have been characterized in fat body and hemocytes from tobacco hornworms, Manduca sexta. Here we show that bacterial challenge stimulated increased PLA(2) activity in isolated hemocyte preparations, relative to control hemocyte preparations that were challenged with water. The increased activity was detected as early as 15 s post-challenge and lasted for at least 1 h. The increased activity depended on a minimum bacterial challenge dose, and was inhibited in reactions conducted in the presence of oleyoxyethylphosphorylcholine, a site-specific PLA(2) inhibitor. In independent experiments with serum prepared from whole hemolymph, we found no PLA(2) activity was secreted into serum during the first 24 h following bacterial infection. We infer that a hemocytic intracellular PLA(2) activity is increased immediately an infection is detected. The significance of this enzyme lies in its role in launching the biosynthesis of eicosanoids, which mediate cellular immune reactions to bacterial infection.     

Genome Sequence of Hybrid Vibrio cholerae O1 MJ-1236, B-33, and CIRS101 and Comparative Genomics with V. cholerae

The genomes of Vibrio cholerae O1 Matlab variant MJ-1236, Mozambique O1 El Tor variant B33, and altered O1 El Tor CIRS101 were sequenced. All three strains were found to belong to the phylocore group 1 clade of V. cholerae, which includes the 7th-pandemic O1 El Tor and serogroup O139 isolates, despite displaying certain characteristics of the classical biotype. All three strains were found to harbor a hybrid variant of CTXΦ and an integrative conjugative element (ICE), leading to their establishment as successful clinical clones and the displacement of prototypical O1 El Tor. The absence of strain- and group-specific genomic islands, some of which appear to be prophages and phage-like elements, seems to be the most likely factor in the recent establishment of dominance of V. cholerae CIRS101 over the other two hybrid strains.Vibrio cholerae, a bacterium autochthonous to the aquatic environment, is the causative agent of cholera, a life-threatening disease that causes severe, watery diarrhea. Cholera bacteria are serogrouped based on their somatic O antigens, with more than 200 serogroups identified to date (6). Only toxigenic strains of serogroups O1 and O139 have been identified as agents of cholera epidemics and pandemics; serogroups other than O1 and O139 have the potential to cause mild gastroenteritis or, rarely, local outbreaks. Genes coding for cholera toxin (CTX), ctxAB, and other virulence factors have been shown to reside in bacteriophages and various mobile genetic elements. In addition, V. cholerae serogroup O1 is differentiated into two biotypes, classical and El Tor, by a combination of biochemical traits, by sensitivity to biotype-specific bacteriophages, and more recently by nucleotide sequencing of specific genes and by molecular typing (5, 17, 19).There have been seven pandemics of cholera recorded throughout human history. The seventh and current pandemic began in 1961 in the Indonesian island of Sulawesi and subsequently spread to Asia, Africa, and Latin America; the six previous pandemics are believed to have originated in the Indian subcontinent. Isolates of the sixth pandemic were almost exclusively of the O1 classical biotype, whereas the current (seventh) pandemic is dominated by the V. cholerae O1 El Tor biotype as the causative agent, a transition occurring between 1923 and 1961. Today, the disease continues to remain a scourge in developing countries, confounded by the fact that V. cholerae is native to estuaries and river systems throughout the world (8).Over the past 20 years, several new epidemic lineages of V. cholerae O1 El Tor have emerged (or reemerged). For example, in 1992, a new serogroup, namely, O139 of V. cholerae, was identified as the cause of epidemic cholera in India and Bangladesh (25). The initial concern was that a new pandemic was beginning; however, the geographic range of V. cholerae O139 is currently restricted to Asia. Additionally, V. cholerae O1 hybrids and altered El Tor variants have been isolated repeatedly in Bangladesh (Matlab) (23, 24) and Mozambique (1). Altered V. cholerae O1 El Tor isolates produce cholera toxin of the classical biotype but can be biotyped as El Tor by conventional phenotypic assays, whereas V. cholerae O1 hybrid variants cannot be biotyped based on phenotypic tests and can produce cholera toxin of either biotype. These new variants have subsequently replaced the prototype seventh-pandemic V. cholerae O1 El Tor strains in Asia and Africa, with respect to frequency of isolation from clinical cases of cholera (27).Here, we report the genome sequence of three V. cholerae O1 variants, MJ-1236, a Matlab type I hybrid variant from Bangladesh that cannot be biotyped by conventional methods, CIRS101, an altered O1 El Tor isolate from Bangladesh which harbors ctxB of classical origin, and B33, an altered O1 El Tor isolate from Mozambique which harbors classical CTXΦ, and we compare their genomes with prototype El Tor and classical genomes. From an epidemiological viewpoint, among the three variants characterized in this study, V. cholerae CIRS101 is currently the most “successful” in that strains belonging to this type have virtually replaced the prototype El Tor in Asia and many parts of Africa, notably East Africa. This study, therefore, gives us a unique opportunity to understand why V. cholerae CIRS101 is currently the most successful El Tor variant.     

Effect of weight loss on P wave dispersion in obese subjects

Objective: The aim of this study was to investigate effect of loss weight on P wave dispersion in obese subjects. Research Methods and Procedures: After a 12‐week weight loss program (diet and medical therapy), a total of 30 (24 women and six men) obese subjects who had lost at least 10% of their original weight were included in the present study. All subjects underwent a routine standard 12‐lead surface electrocardiogram. Electrocardiograms were transferred to a personal computer by a scanner and then magnified 400 times by Adobe Photoshop software (Adobe Systems, Mountain View, CA). P wave dispersion, which is also defined as the difference between the maximum P wave duration and the minimum P wave duration, was also calculated. Results: After a 12‐week weight loss program, BMI (p < 0.001), maximum P wave duration (p < 0.001), and P wave dispersion (p < 0.001) significantly decreased. The mean percentage of weight loss was 13% (10% to 20.3%). The decrease in the level of P wave dispersion (21 ± 10 and 7 ± 12 ms, p < 0.002) was more prominent in Group II (≥12% loss of their original weight) than Group I (<12% loss of their original weight) after the weight loss program. A statistically significant correlation between decrease in the level of P wave dispersion and percentage of weight loss was found (r = 0.624, p < 0.001). Discussion: Substantial weight loss in obese subjects is associated with a decrease of P wave duration and dispersion. Therefore, these observations suggest that substantial weight loss is associated with improvement in atrial repolarization abnormalities in obese subjects.     

Impact of tannic acid on blood pressure,oxidative stress and urinary parameters in L-NNA-induced hypertensive rats

Hypertension is a major health problem with increasing prevalence around the world. Tannic acid is water-soluble polyphenol that is present in tea, green tea, coffee, red wine, nuts, fruits and many plant foods. It has been reported to serve as an antioxidant or a pro-oxidant depending on the type of cells and its concentration. The purpose of our study was to evaluate the effect of tannic acid on systolic blood pressure, oxidative stress and some urinary parameters in the rat model of essential hypertension. Blood pressures of all rats were measured using the tail-cuff method. The nitric oxide synthase inhibitor N (omega)-nitro-L-arginine was administered orally at a dose of 0.5 g/l/day for 15 days to rats in order to create an animal model of hypertension. Tannic acid was intraperitoneally injected at a dose of 50 mg/kg for 15 days. Superoxide dismutase, catalase activity and the concentration of malondialdehyde (MDA) were determined in blood plasma and homogenates of heart, liver and kidney. In order to evaluate renal functions, urine pH, urine volume, urine creatine, uric acid, and urea nitrogen values were measured. Compared with the hypertension group, a decrease in MDA concentrations of heart tissue (p < 0.01), urea nitrogen values (p < 0.01) and urine volumes (p < 0.001) were established in hypertension + tannic acid group. There was also a decrease in blood pressure values (20th and 30th days) of this group, but there was no a statistical difference according to hypertension group. The findings of our research show the effect of tannic acid in lowering blood pressure in hypertensive rats.     

Purification of lactoperoxidase from creek-water buffalo milk and investigation of kinetic and antibacterial properties

Water buffalo lactoperoxidase (WBLP) was purified with Amberlite CG 50 H+ resin, CM Sephadex C-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography from skim milk. All purification steps of the WBLP were shown with SDS-PAGE and Rz (A412/A280) controlled the purification degree of the enzyme. Rz value for the purified WBLP was 0.8. To determine purification steps and kinetic properties, the activity of enzyme was measured by using 2,2-azino-bis-(3-ethylbenzthiazoline-6 sulfonic acid) diammonium salt (ABTS) as a choromogenic substrate at pH=6. Km, Vmax, optimum pH, and optimum temperature for the WBLP were found by means of graphics for ABTS as substrates. Optimum pH and optimum temperature of the WBLP were 6 and 60 degrees C, respectively. Km value at optimum pH and optimum temperature for the WBLP was 0.82 mM. Vmax value at optimum pH and optimum temperature was 13.7 micromol/mL x min. Km value at optimum pH and 25 degrees C for the WBLP was 0.77 mM. Vmax value at optimum pH and 25 degrees C was 4.83 micromol/mL x min. The purified WBLP was found to have high antibacterial activity in a thiocynate-H2O2 medium for some pathogenic bacteria, such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginose, Shigella sonnei, Staphylococcus saphrophyticus, Staphylococcus epidermidis, and Shigella dysenteriae and compared with well known antibacterial substances such as tetracycline, penicillin, and netilmicine.     

The Effects of Chromium Picolinate and Chromium Histidinate Administration on NF-κB and Nrf2/HO-1 Pathway in the Brain of Diabetic Rats

The objective of this experiment was to investigate the effects of supplemental chromium picolinate (CrPic) and chromium histidinate (CrHis) on nuclear factor-kappa B (NF-??B p65) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling pathway in diabetic rat brain. Nondiabetic (n?=?45) and diabetic (n?=?45) male Wistar rats were either not supplemented or supplemented with CrPic or CrHis via drinking water to consume 8???g elemental chromium (Cr) per day for 12?weeks. Diabetes was induced by streptozotocin injection (40?mg/kg i.p., for 2?weeks) and maintained by high-fat feeding (40?%). Diabetes was associated with increases in cerebral NF-??B and 4-hydroxynonenal (4-HNE) protein adducts and decreased in cerebral nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor, alpha (I??B??) and Nrf2 levels. Both Cr chelates were effective to decrease levels of NF-??B and 4-HNE protein adducts and to increase levels of I??B?? and Nrf2 in the brain of diabetic rats. However, responses of these increases and decreases were more notable when Cr was supplemented as CrHis than as CrPic. In conclusion, Cr may play a protective role in cerebral antioxidant defense system in diabetic subjects via the Nrf2 pathway by reducing inflammation through NF-??B p65 inhibition. Histidinate form of Cr was superior to picolinate form of Cr in reducing NF-??B expression and increasing Nrf2 expression in the brain of diabetic rats.     

Gastroprotective,cytoprotective and antioxidant effects of Oleum cinnamomi on ethanol induced damage

Peptic ulcer disease is a gastrointestinal disorder defined by mucosal damage and free oxygen radicals associated with peptic ulcer and gastritis. Cinnamon is a traditional herb used for many diseases and it has also effects as an antioxidant, anti-inflammatory, antispasmodic and anti-ulcerative. Our research is based on oxidative stress and effects of Oleum cinnamomi on stomach, liver and kidney disorders induced by ethanol. In our experiment, 2–3 month old male Sprague–Dawley rats were used. One hour before the mucosal damage induced by 70 % ethanol, O. cinnamomi (2.5 ml/kg) was added into the groups. Gastric pH, analysis of gastric mucus and ulcer index were calculated from samples obtained from the stomach. Superoxide dismutase (SOD), malondialdehyde and catalase (CAT) levels were determined in stomach, liver and kidney homogenates and erythrocyte hemolysate. Histopathological examination of stomach, liver and kidney were determined with H&E staining. The non-treated ulcerative group showed higher scores than the control group which was treated with O. cinnamomi, when ulcer scores, gastric mucus and pH level of stomach are compared. Increased lipid peroxidation levels were observed in the liver, kidney and erythrocyte hemolysate. SOD activity was decreased in liver whereas increased in stomach of ethanol treated ulcerative groups. CAT levels were increased in stomach and liver of ethanol treated rats. Histopathological findings showed that ethanol treatment cause multiply organ damage such as stomach, liver and kidney injury. O. cinnamomi treatment protected these tissues from ethanol-induced damage. Consequently, the current investigation shows that O. cinnamomi has protective effects on ethanol-induced oxidative and mucosal damage.     

Effects of colloidal fouling and gas sparging on microfiltration of yeast suspension

Cross-flow microfiltration is an important step in separating Baker’s yeast (Saccharomyces cerevisiae) from aqueous suspension in many processes. However the permeate flux often declines rapidly due to colloidal fouling of membranes and concentration polarisation. The present work explores the possibility of maintaining acceptable permeate flux by co-current sparging of gas along with the feed, which would scour away colloidal deposits and reduce concentration polarisation of membranes. In this work, both washed and unwashed yeast were used to study the effect of washing to reduce protein fouling of membranes. It was found that permeate flux increased by 45% for liquid throughput of 75 kg/h for a feed concentration of 2.0 kg/m³ of washed yeast as compared with unwashed yeast suspension without gas sparging. For washed yeast suspension, the increase in gas flow rate from 0.5 lpm to 1.5 lpm (30 l/h to 90 l/h) had beneficial effect on permeate flux. It is concluded that in the present case, the gas flow rate should be less than or equal to the liquid flow rate for enhancement of permeates flux.