Hyperoxia and recovery from hypoxia alter collagen in peripheral pulmonary arteries similarly

Chronic hypoxia causes pulmonary hypertension, the mechanism of which includes altered collagen metabolism in the pulmonary vascular wall. This chronic hypoxic pulmonary hypertension is gradually reversible upon reoxygenation. The return to air after the adjustment to chronic hypoxia resembles in some aspects a hyperoxic stimulus and we hypothesize that the changes of extracellular matrix proteins in peripheral pulmonary arteries may be similar. Therefore, we studied the exposure to moderate chronic hyperoxia (FiO2 = 0.35, 3 weeks) in rats and compared its effects on the rat pulmonary vasculature to the effects of recovery (3 weeks) from chronic hypoxia (FiO2 = 0.1, 3 weeks). Chronically hypoxic rats had pulmonary hypertension (Pap = 26 +/- 3 mm Hg, controls 16 +/- 1 mm Hg) and right ventricular hypertrophy. Pulmonary arterial blood pressure and right ventricle weight normalized after 3 weeks of recovery in air (Pap = 19 +/- 1 mm Hg). The rats exposed to moderate chronic hyperoxia also did not have pulmonary hypertension (Pap = 18 +/- 1 mm Hg, controls 17 +/- 1 mm Hg). Collagenous proteins isolated from the peripheral pulmonary arteries (100-300 microm) were studied using polyacrylamide gel electrophoresis. A dominant low molecular weight peptide (approx. 76 kD) was found in hypoxic rats. The proportion of this peptide decreases significantly in the course of recovery in air. In addition, another larger peptide doublet was found in rats recovering from chronic hypoxia. It was localized in polyacrylamide gels close to the zone of alpha2 chain of collagen type I. It was bound to anticollagen type I antibodies. An identically localized peptide was found in rats exposed to moderate chronic hyperoxia. The apparent molecular weight of this collagen fraction suggests that it is a product of collagen type I cleavage by a rodent-type interstitial collagenase (MMP-13). We conclude that chronic moderate hyperoxia and recovery from chronic hypoxia have a similar effect on collagenous proteins of the peripheral pulmonary arterial wall.     

Rylux BSU stimulates spore germination in Trichophyton mentagrophytes and Aspergillus fumigatus and increases the survival rate after UV-irradiation

Calcofluor-allied optical brightener Rylux BSU stimulated spore germination rate inTrichophyton mentagrophytes andAspergillus fumigatus both if supplemented into Sabouraud glucose agar and if used for pretreatment of spore suspension prior to inoculation at low concentrations. Maximum stimulation of germination was obtained if 0.2% Rylux BSU was used for pretreatment in aqueous solution for 1 d prior to inoculation (130% inT. mentagrophytes and 150% inA. fumigatus, respectively). Pretreatment with 1% Rylux BSU provided strong protection against UV-irradiation and resulted in increased yields of cultural variants after UV-irradiation.     

Elevational contrast in predation and parasitism risk to caterpillars in a tropical rainforest

Invertebrate predators and parasitoids are among the most important natural enemies of insect herbivores. Yet, the strength of natural enemy pressure along an altitudinal gradient and interactions between the groups of natural enemies (such as predation on parasitized prey) are not well known. Various methods are used to reveal the mortality factors of herbivores. Predation pressure is usually assessed through exposure of artificial prey. However, this method cannot provide information about the attacks of parasitoids, or their eventual interactions with predators. Furthermore, artificial or dead prey might not attract predators because they do not show expected host behavior, and this method mostly cannot distinguish between predation and scavenging. For the first time in a tropical rainforest, we quantified elevational contrast in mortality factors using exposure of live caterpillars. We exposed a total of 800 live caterpillars of Talanga excelsalis moresbyensis Strand (Lepidoptera: Crambidae) on saplings of Ficus copiosa Steud. (Moraceae) at two elevations in primary tropical rain forest in Papua New Guinea (200 and 1 200 m a.s.l.). We exposed the caterpillars in two treatments: exposed to and protected from invertebrate predators and parasitoids. Disappearance of caterpillars was significantly higher in the exposed treatment. Furthermore, caterpillar disappearance was significantly higher in lowlands than in highlands (43 vs. 12%). We consider the vast majority of the disappearance to be due to predation, as migration of the caterpillars from the focal trees was not observed (except one caterpillar). This estimate of invertebrate predation rate corresponds with studies which used artificial caterpillar models. No significant difference in parasitism rate between the two elevations was observed (12 vs. 13%). The combination of the disappearance and parasitism rate patterns means that larval parasitoids face stronger pressure from invertebrate predators through higher predation of their hosts in the lowlands than in the highlands.     

Exposure to 17β-Oestradiol Induces Oxidative Stress in the Non-Oestrogen Receptor Invertebrate Species Eisenia fetida

Background

The environmental impacts of various substances on all levels of organisms are under investigation. Among these substances, endocrine-disrupting compounds (EDCs) present a threat, although the environmental significance of these compounds remains largely unknown. To shed some light on this field, we assessed the effects of 17β-oestradiol on the growth, reproduction and formation of free radicals in Eisenia fetida.

Methodology/Principal Findings

Although the observed effects on growth and survival were relatively weak, a strong impact on reproduction was observed (50.70% inhibition in 100 μg/kg of E₂). We further demonstrated that the exposure of the earthworm Eisenia fetida to a contaminant of emerging concern, 17β-oestradiol (E₂), significantly affected the molecules involved in antioxidant defence. Exposure to E₂ results in the production of reactive oxygen species (ROS) and the stimulation of antioxidant systems (metallothionein and reduced oxidized glutathione ratio) but not phytochelatins at both the mRNA and translated protein levels. Matrix-assisted laser desorption/ionization (MALDI)-imaging revealed the subcuticular bioaccumulation of oestradiol-3,4-quinone, altering the levels of local antioxidants in a time-dependent manner.

Conclusions/Significance

The present study illustrates that although most invertebrates do not possess oestrogen receptors, these organisms can be affected by oestrogen hormones, likely reflecting free diffusion into the cellular microenvironment with subsequent degradation to molecules that undergo redox cycling, producing ROS, thereby increasing environmental contamination that also perilously affects keystone animals, forming lower trophic levels.     

CysTRAQ - A combination of iTRAQ and enrichment of cysteinyl peptides for uncovering and quantifying hidden proteomes

Shotgun proteomics is capable of characterizing differences in both protein quality and quantity, and has been applied in various biomedical applications. Unfortunately, the high complexity and dynamic range of proteins in studied samples, clinical in particular, often hinders the identification of relevant proteins. Indeed, information-rich, low abundance proteins often remain undetected, whereas repeatedly reported altered concentrations in high abundance proteins are often ambiguous and insignificant. Several techniques have therefore been developed to overcome this obstacle and provide a deeper insight into the proteome. Here we report a novel approach, which enables iTRAQ reagent quantitation of peptides fractionated based on presence of a cysteine residue (thus CysTRAQ). For the first time, we prove that iTRAQ quantitation is fully compatible with cysteinyl peptide enrichment and is not influenced by the fractionation process. Moreover, the employment of the method combined with high-resolution TripleTOF 5600 mass spectrometer for very fast MS/MS acquisition in human amniotic fluid analysis significantly increased the number of identified proteins, which were simultaneously quantified owing to the introduction of iTRAQ labeling. We herein show that CysTRAQ is a robust and straightforward method with potential application in quantitative proteomics experiments, i.e. as an alternative to the ICAT reagent approach.     

A porcine model of skin wound infected with a polybacterial biofilm

A clinically relevant porcine model of a biofilm-infected wound was established in 10 minipigs. The wounds of six experimental animals were infected with a modified polymicrobial Lubbock chronic wound biofilm consisting of Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Bacillus subtilis. Four animals served as uninfected controls. The wounds were monitored until they had healed for 24 days. The biofilm persisted in the wounds up to day 14 and significantly affected healing. The control to infected healed wound area ratios were: 45%/21%, 66%/37%, and 90%/57% on days 7, 10 and 14, respectively. The implanted biofilm prolonged inflammation, increased necrosis, delayed granulation and impaired development of the extracellular matrix as seen in histological and gene expression analyses. This model provides a therapeutic one-week window for testing of anti-biofilm treatments and for research on the pathogenesis of wound infections in pig that is clinically the most relevant animal wound healing model.     

Occurrence of betulinic acid in different callus cultures of Solanum aviculare

Betulinic acid (3β-hydroxy-lup-20(29)-en-28-oic acid) was obtained from in vitro cultures of Solanum aviculare in yields up to 3% of the dry weight. This is a further example of overproduction by cells cultured in vitro of a product not found in the original parent plant.     

Ethanol-induced death and lipid composition ofSaccharomyces cerevisiae: A comparative study of the role of sterols

Ethanol tolerance of fourSaccharomyces cerevisiae strains characterized by different amounts of Δ^5,7-sterols was tested. The individual tolerances did not correlate with the strains sterol levels. The highly and medium-accumulating strains exhibited the highest and lowest ethanol tolerances, respectively.     

Extension of the Nef reaction to C-glycosylnitromethanes

Acid-catalysed methanolysis of 3,4,5,6-tetra-O-acetyl-1,2-dideoxy-l-arabino-hex-1-enitol proceeds via a cascade set of consecutive reactions resulting in its regiospecific conversion to a mixture of alpha- and beta-C-L-arabinofuranosylmethanal dimethyl acetals and a mixed internal methyl acetal. Structures of the final products of the overall process provide unique evidence that a kinetically controlled, five-membered-ring closure precedes a six-membered-ring closure in reversible systems capable of giving both five-membered and six-membered all-sp3-atom rings. Determination of the reaction intermediate enabled extension of the Nef reaction to C-glycosylnitromethanes. Protonated aci-nitro forms of C-glycosylnitromethanes that are resistant to the Nef reaction in aqueous acidic media undergo a modified Nef reaction in acidified methanol, and the corresponding C-glycosylmethanal dimethyl acetals with alpha-L-arabinopyranosyl, beta-D-glucopyranosyl, beta-D-galactopyranosyl, beta-D-mannopyranosyl and beta-L-rhamnopyranosyl configurations were obtained in moderate yields.