Salmonella typhimurium infections in BALB/c mice: a comparison of tissue bioluminescence, tissue cultures and mice clinical scores

In response to systemic infection, mice usually present specific behaviors such as reduced activity and feeding, ruffled fur, hunched position, ataxia and tremor. We aimed to compare tissue bioluminescence, tissue cultures and clinical scores of BALB/c mice as potentially complementary outcome measures of Salmonella disease progression In Balb/c mice. The clinical status of the mice was assessed by visual examination for motility, ruffled fur, hunched position, feeding, ataxia and tremor. Patterns of bioluminescent light emission indicated the progression of infection from the abdominal region (initial site) to secondary tissue sites, which was indicative of systemic infection. As the severity and progression of infection increased, the bioluminescence signal became both more prominent and more anatomically disseminated. Bioluminescent Imaging (BLI) of Salmonella that have been genetically engineered to be bioluminescent is a new method that gives the opportunity to track Salmonella dissemination in mice. BLI is a helpful method to estimate tissue Salmonella concentration and may reduce the number of mice used in experiments, providing the opportunity to obtain serial assessments of disease progression in a single mouse subject. Clinical scores helped us to assess the clinical status of BALB/c mice in systemic Salmonella infections.     

Biochemical analysis and investigation on the prospective applications of alkaline protease from a <Emphasis Type="Italic">Bacillus cereus</Emphasis> strain

Proteases have prospective financial and environment-friendly applications; hence attention is focused currently on the finding of new protease producing microorganism so as to meet the requirements of industry. A thermophilic bacterial strain producing extracellular protease activity was isolated from soil and identified as Bacillus cereus by analysis of 16S rRNA. Protease production by the microorganism was improved by studying the impact of the type of nitrogen and carbon source, fermentation period, growth temperature and initial pH of the culture medium in cultivation optimization experiments. The enzyme was purified to homogeneity in two step procedure involving Sephadex G-75 and Q-Sepharose chromatography. The molecular weight of purified enzyme was found to be 58 kDa by SDS-PAGE. Protease exhibited a pH and temperature optima of 7.5 and 60°, respectively. The enzyme was active in the pH range of 6.0–9.0 and stable up to 70°C. Histological analysis of protease treated goat and cow skin pelts showed complete removal of non leather forming structures such as hair shaft, hair follicles and glandular structures. The protease showed the stain removing property from blood stained cotton cloth and found to be compatible with six commercially available detergents. The protease could release peptides from natural proteins after digestion of coagulated egg albumin and blood clot.     

Can Mosquito Magnet® substitute for human-landing catches to sample anopheline populations?

The efficiency of the Mosquito Magnet Liberty Plus? (MMLP) trap was evaluated in comparison to human-landing catches (HLCs) to sample anopheline populations in Jabillal, state of Bolivar, southern Venezuela. The village comprised 37 houses and a population of 101; malaria in this village is primarily due to Plasmodium vivax and the Annual Parasite Index is 316.8 per 1,000 population. A longitudinal study was conducted between June 2008-January 2009 for three nights per month every two months between 17:30 pm-21:30 pm, a time when biting mosquitoes are most active. Anopheles darlingi and Anopheles nuneztovari were the most common species collected by both methods, whereas Anopheles marajoara was more abundant according to the HLC method. The MMLP trap was more efficient for collecting An. nuneztovari [63%, confidence interval (CI): 2.53] than for collecting An. darlingi (31%, CI: 1.57). There were significant correlations (p < 0.01) between the two methods for An. darlingi [Pearson correlation (R2) = 0.65] and An. nuneztovari (R2 = 0.48). These preliminary results are encouraging for further investigations of the use of the MMLP trap for monitoring anopheline populations in remote malaria-endemic areas in the Amazon Basin.     

Enrichment materials do not negatively affect reproductive success and offspring survival and weight in mice

Environmental enrichment is designed to improve the overall welfare of laboratory animals, including mice. Few studies have directly assessed the effects of different types of enrichment on mouse offspring survival and growth. The authors examined how survival and growth of C57BL/6 mouse pups are affected by three kinds of cage enrichment materials: compressed cotton squares, two-ply tissues and plastic igloos. During the last week of gestation and the first two weeks postpartum, the authors observed cages with litters and noted use of the enrichment materials, quality of nest construction, number of pups per litter and weight of pups. Both the first and second litters were evaluated for each dam. Dams and pups had continuous contact with the enrichment materials, especially cotton squares and tissues. Neither the presence nor the type of enrichment material influenced the survival and weight of offspring, suggesting that the use of such materials does not negatively impact reproductive success or offspring survival.     

Immune role of MrNFκBI-α, an IκB family member characterized in prawn M. rosenbergii

NF kappa B inhibitor alpha (MrNFκBI-α) was sequenced from a freshwater prawn Macrobrachium rosenbergii. The MrNFκBI-α protein contains a long ankyrin repeat region circular domain between 193 and 413 along with its 6 repeats (ankyrin repeat 1,2,3,4,5 and 6). An IκB degradation motif and a putative PEST motif is present at 37-64 and 418-471 of the N- and C-terminal regions of MrNFκBI-α respectively. The gene expressions of MrNFκBI-α in healthy and infectious hematopoietic and hypodermal necrosis virus (IHHNV), poly I:C, Aeromonas hydrophila and Enterococcus faecium injected M.?rosenbergii were examined using quantitative real time PCR. The MrNFκBI-α is expressed in all the tissues taken for examination and the highest is observed in hemocytes. The MrNFκBI-α gene expression is strongly up-regulated in hemocytes of prawn after IHHNV, poly I:C, A.?hydrophila and E.?faecium infection. This result indicates an important role of MrNFκBI-α in M.?rosenbergii immune system. This, however, remains to be verified by further studies.     

Effects of different types of warm-up on swimming performance, reaction time, and dive distance

The purpose of this study was to evaluate the effects of 3 types of warm-up (WU) on swimming performance, reaction time, and dive distance. In repeated-measures counterbalanced design, National Collegiate Athletic Association Division I swimmers (n = 16) used 3 WUs before performing 50-yd (45.7-m) freestyle swim trials. The WU consisted of (a) no WU, (b) short WU (50-yd at 40% of swimmers' maximal effort and 50-yd at 90%), and (c) regular WU (usual precompetition WU). The mean 50-yd time was significantly faster (p = 0.01) after the regular WU (24.95 ± 1.53 seconds) when compared with that of the short WU (25.26 ± 1.61 seconds). However, individual data indicated that 19% of the participants performed their best in the 50-yd category after short, 37% after no, and 44% after regular WU. Heart rate was significantly higher (p = 0.01) after regular WU (100 ± 13 b·min(-1)) when compared with that of the no WU category (88 ± 18 b·min(-1)). However, no significant differences among WUs were found for reaction time (p = 0.96), rating of perceived exertion post 50-yd time trial (p = 0.11), dive distance (p = 0.67), or stroke count (p = 0.23). In conclusion, the average regular WU was better than short or noWU to achieve the fastest mean time in the 50-yd freestyle; however, some individual performances were faster after WUs different from their regular approach.     

The molecular mechanism of toxin-induced conformational changes in a potassium channel: relation to C-type inactivation

Recently, a solid-state NMR study revealed that scorpion toxin binding leads to conformational changes in the selectivity filter of potassium channels. The exact nature of the conformational changes, however, remained elusive. We carried out all-atom molecular dynamics simulations that enabled us to cover the complete pathway of toxin approach and binding, and we validated our simulation results by using solid-state NMR data and electrophysiological measurements. Our structural model revealed a mechanism of cooperative toxin-induced conformational changes that accounts both for the signal changes observed in solid-state NMR and for the tight interaction between KcsA-Kv1.3 and Kaliotoxin. We show that this mechanism is structurally and functionally closely related to recovery from C-type inactivation. Furthermore, our simulations indicate heterogeneity in the binding modes of Kaliotoxin, which might serve to enhance its affinity for KcsA-Kv1.3 further by entropic stabilization.     

Production, purification and characterization of beta-1,4-endoglucanase from a novel bacterial strain CTP-09 of a Bacillus sp

Bacillus strain CTP-09 yielded maximum productivity (1120 IU/L.h) of extracellular endoglucanase (CMCase) on 0.5% cellobiose after 10 h fermentation at 55 degrees C. The purified enzyme is mono-meric in nature and exhibits stability up to 80 degrees C and over a pH range (6.0-9.0). Activation energy, enthalpy and entropy of catalysis, and inactivation indicated that this CMCase is highly thermos-table. Purified enzyme possessed high power of defibrillation of textile and was minutely inhibited by anionic detergent and oxidizing agent comparable with inhibition by commercial enzyme. This polypeptide could be exploited for mass production and application in local industries.