A Trichrome Stain for Insect Material

Deparaffinized insect sections are brought down to water and overstained in a 0.1% solution of azocarmine G in 1% acetic acid. They are then destained in a saturated solution of orange G until the azocarmine G is removed from the endocuticle and the latter is colored pale yellow. After washing, the sections are transferred to a 5.0 % solution of phosphotungstic acid in water for 3 min. They are then rinsed in distilled water and stained in a 0.1% solution of methyl green in 1% acetic acid until the endocuticle is green. Differentiation is done in 2 changes of 95% alcohol. The sections are then dehydrated either in absolute alcohol or dioxane, cleared in a mixture of “camsal”, eucalyptol, dioxane, and paraldehyde (1:2:2:1), and mounted in Mohr and Wehrle's medium, a mountant of the Euparal type.     

The pedagogical genealogy of Terrance J. Beveridge--a legacy of bonds

Terrance J. Beveridge (TJB) was a professor at the University of Guelph for nearly three decades. He died on September 10, 2007. TJB was a pioneer who pushed the frontier of microbiology and bacteriology. His legacy includes 22 postdoctoral scholars and 24 graduate students. His two dozen graduate student progeny have, in turn, mentored at least 52 additional graduate students. This paper presents TJB's pedagogical tree and touches on many of the topics that he studied during his life including: bacteria cell surfaces, biomineralization, biofilms, and geomicrobiology.     

The role of F-series prostaglandins as reproductive priming pheromones in the brown trout

Electrophysiological studies demonstrated that the olfactory epithelium of mature male brown trout Salmo trutta parr was acutely sensitive to F-series prostaglandins (PGFs) PGF_1α and PGF_2α, with detection threshold concentrations of 10⁻¹¹ M. The olfactory epithelium was also sensitive to the PGF metabolite 15-ketoPGF_2α (threshold 10⁻⁸ m), but did not detect a further metabolite, 13,14,-dihydro-15-ketoPGF_2α Immature brown trout did not detect any of the prostaglandins tested. Exposure of mature male brown trout parr to waterborne PGF_1α and PGF_2α (concentration 10⁻⁸ m), resulted in significant increases in levels of expressible milt and the plasma concentrations of 17,20β-dihydroxy-4-pregnen-3-one, testosterone and 11-ketotestosterone. The olfactory epithelium of both immature and mature male brown trout parr was sensitive to the urine and ovarian fluid from ovulated female brown trout. Exposure of mature male brown trout parr to ovarian fluid resulted in an increase in the levels of plasma 17,20β-dihydroxy-4-pregnen-3-one whilst exposure to urine increased the levels of expressible milt. In addition, PGF_2α was found to be present within both the urine and ovarian fluid of mature female brown trout. It is suggested that the F-series prostaglandins have a role as priming pheromones in male brown trout.     

An evaluation of periphyton community structure and function on tile and cobble substrata in experimental stream mesocosms

Periphyton communities are an ecologically important source of information when conducting experimental stream ecotoxicological studies. Experimental stream studies often utilize unreplicated systems in order to understand dose-response phenomena. The objective of this study was to examine the robustness of such a dose-response investigation. Autotrophic and heterotrophic periphyton were evaluated in replicated control experimental streams with open recruitment (once-through flow design). Measurements of population and community structure and community function over an eleven week colonization period were made on unglazed clay tile and cobble substrata. Several measures were significantly different during the study; however, most of these were a result of initial stochastic colonization events or associated with relatively rare algal populations. During the latter half of the study autotrophic and heterotrophic community measurements on tile and cobble substrata displayed similar trends in both control streams. Population and community metrics were significantly different for approximately 5% of the 400 measurements made after the initial sampling. These results strongly suggest that the driving forces behind structuring aquatic population and community responses will be test chemical exposure and not spuriously developed stream ecosystems with individual trajectories. Recruitment in these open systems is evenly distributed across the replicated experimental stream ecosystems.     

Polymorphisms in Fibronectin Binding Proteins A and B among Staphylococcus aureus Bloodstream Isolates Are Not Associated with Arthroplasty Infection

Background

Nonsynonymous single nucleotide polymorphisms (SNPs) in fibronectin binding protein A (fnbA) of Staphylococcus aureus are associated with cardiac device infections. However, the role of fnbA SNPs in S. aureus arthroplasty infection is unknown.

Methods

Bloodstream S. aureus isolates from a derivation cohort of patients at a single U.S. medical center with S. aureus bacteremia (SAB) and prosthetic hip or knee arthroplasties that were infected (PJI, n = 27) or uninfected (PJU, n = 43) underwent sequencing of fnbA and fnbB. A validation cohort of S. aureus bloodstream PJI (n = 12) and PJU (n = 58) isolates from Germany also underwent fnbA and fnbB sequencing.

Results

Overall, none of the individual fnbA or fnbB SNPs were significantly associated with the PJI or PJU clinical groups within the derivation cohort. Similarly, none of the individual fnbA or fnbB SNPs were associated with PJI or PJU when the analysis was restricted to patients with either early SAB (i.e., bacteremia occurring <1 year after placement or manipulation of prostheses) or late SAB (i.e., bacteremia >1 year after placement or manipulation of prostheses).

Conclusions

In contrast to cardiac device infections, there is no association between nonsynonymous SNPs in fnbA or fnbB of bloodstream S. aureus isolates and arthroplasty infection. These results suggest that initial steps leading to S. aureus infection of cardiovascular and orthopedic prostheses may arise by distinct processes.     

Impact of Anti-Peroxynitrite-Damaged-Thymidine- Monophosphate Antibodies on Disease Activity in Patients with Systemic Lupus Erythematosus

Present study probes the role of peroxynitrite (ONOO^-)-modified thymidine-5′-monophosphate (TMP) in SLE patients with different disease activity scores according to the SLE Disease Activity Index (SLEDAI). Serum analysis showed significant increased number of subjects positive for anti-ONOO^--TMP-protein antibodies in SLE patients with different SLEDAI scores. Interestingly, the levels of these antibodies were significantly higher among SLE patients, whose SLEDAI scores were ≥20. In addition, a significant correlation was observed between the levels of anti-ONOO^--TMP-protein antibodies and the SLEDAI score (r = 0.595, p < 0.0001). In short, this study shows a positive association between anti-ONOO^--TMP-protein antibodies and SLEDAI. The stronger response observed in patients with higher SLEDAI scores suggests that anti-ONOO^--TMP-protein antibodies may be useful in evaluating the progression of SLE and in elucidating the mechanisms of disease pathogenesis.     

Bioactive endophytic fungi isolated from Caesalpinia echinata Lam. (Brazilwood) and identification of beauvericin as a trypanocidal metabolite from Fusarium sp.

Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL), Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from Fusarium sp. [{"type":"entrez-nucleotide","attrs":{"text":"KF611679","term_id":"560187972","term_text":"KF611679"}}KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular culture assay.     

Rating of perceived exertion as a tool for prescribing and self regulating interval training: a pilot study

The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h⁻¹; RPE: 5.7±1.3 km · h⁻¹) and high-intensity intervals (HR: 7.8±1.9 km · h⁻¹; RPE: 8.2±1.7 km · h⁻¹) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects.     

Deletion of one nucleotide within the homonucleotide tract present in the hsdS gene alters the DNA sequence specificity of type I restriction-modification system NgoAV

As a result of a frameshift mutation, the hsdS locus of the NgoAV type IC restriction and modification (RM) system comprises two genes, hsdS(NgoAV1) and hsdS(NgoAV2). The specificity subunit, HsdS(NgoAV), the product of the hsdS(NgoAV1) gene, is a naturally truncated form of an archetypal specificity subunit (208 N-terminal amino acids instead of 410). The presence of a homonucleotide tract of seven guanines (poly[G]) at the 3' end of the hsdS(NgoAV1) gene makes the NgoAV system a strong candidate for phase variation, i.e., stochastic addition or reduction in the guanine number. We have constructed mutants with 6 guanines instead of 7 and demonstrated that the deletion of a single nucleotide within the 3' end of the hsdS(NgoAV1) gene restored the fusion between the hsdS(NgoAV1) and hsdS(NgoAV2) genes. We have demonstrated that such a contraction of the homonucleotide tract may occur in vivo: in a Neisseria gonorrhoeae population, a minor subpopulation of cells appeared to have only 6 guanines at the 3' end of the hsdS(NgoAV1) gene. Escherichia coli cells carrying the fused gene and expressing the NgoAVΔ RM system were able to restrict λ phage at a level comparable to that for the wild-type NgoAV system. NgoAV recognizes the quasipalindromic interrupted sequence 5'-GCA(N(8))TGC-3' and methylates both strands. NgoAVΔ recognizes DNA sequences 5'-GCA(N(7))GTCA-3' and 5'-GCA(N(7))CTCA-3', although the latter sequence is methylated only on the complementary strand within the 5'-CTCA-3' region of the second recognition target sequence.