A new acridone with antifungal properties against Candida spp. and dermatophytes, and antibiofilm activity against C. albicans.

AIM: The increase in the number of fungal infections worldwide, coupled with the limitations of current antifungal chemotherapy, demand the development of safe and effective new antifungals. Here, we presented the synthesis of a novel acridone (M14) and its antifungal properties against Candida and dermatophytes species. METHODS AND RESULTS: A series of 17 acridones was designed, synthesized and tested for its antifungal activity. The minimum inhibitory concentration (MIC) was determined by the broth microdilution method. Only the acridone M14 showed growth-inhibitory activity against reference strains and clinical isolates of Candida and dermatophytes, with MIC range of 7·81-31·25 µg ml-1 . Moreover, M14 exhibited fungicidal activity and prevented biofilm formation by C. albicans as well as reduced the viability of preformed biofilms, even at sub-MICs. The confocal laser scanning microscopy analysis revealed that C. albicans hyphal growth was completely inhibited in the presence of M14. Similarly, there was a severe inhibition on hyphal growth of Trichophyton rubrum. We also found that M14 has relatively low toxicity to human fibroblasts. CONCLUSIONS: The new acridone M14 has antifungal properties against Candida spp. and dermatophytes, and antibiofilm activity against C. albicans. In addition, M14 is relatively selective to fungal cells compared to human normal cells. SIGNIFICANCE AND IMPACT OF THE STUDY: Because of its in vitro antifungal activity, anti-Candida biofilm effect and moderate cytotoxicity towards normal human cell, M14 may serve as a valuable lead compound to develop a new antifungal agent.

Placebo in sports nutrition: a proof-of-principle study involving caffeine supplementation.

We investigated the effects of supplement identification on exercise performance with caffeine supplementation. Forty-two trained cyclists (age 37 ± 8 years, body mass [BM] 74.3 ± 8.4 kg, height 1.76 ± 0.06 m, maximum oxygen uptake 50.0 ± 6.8 mL/kg/min) performed a ~30 min cycling time-trial 1 h following either 6 mg/kgBM caffeine (CAF) or placebo (PLA) supplementation and one control (CON) session without supplementation. Participants identified which supplement they believed they had ingested ("caffeine", "placebo", "don't know") pre- and post-exercise. Subsequently, participants were allocated to subgroups for analysis according to their identifications. Overall and subgroup analyses were performed using mixed-model and magnitude-based inference analyses. Caffeine improved performance vs PLA and CON (P ≤ 0.001). Correct pre- and post-exercise identification of caffeine in CAF improved exercise performance (+4.8 and +6.5%) vs CON, with slightly greater relative increases than the overall effect of caffeine (+4.1%). Performance was not different between PLA and CON within subgroups (all P > 0.05), although there was a tendency toward improved performance when participants believed they had ingested caffeine post-exercise (P = 0.06; 87% likely beneficial). Participants who correctly identified placebo in PLA showed possible harmful effects on performance compared to CON. Supplement identification appeared to influence exercise outcome and may be a source of bias in sports nutrition.

In vitro evaluation of the acquisition of resistance, antifungal activity and synergism of Brazilian red propolis with antifungal drugs on Candida spp.

AIMS: To evaluate the ability of Candida parapsilosis and Candida glabrata to develop phenotypic resistance to a benzophenone enriched fraction obtained from Brazilian red propolis (BZP-BRP) as compared to fluconazole (FLC). To investigate possible synergy between BZP-BRP and FLC and anidulafungin (AND). METHODS AND RESULTS: To analyse the development of resistance, isolates susceptible to these antifungals were cultured in increasing concentrations of FLC and BZP-BRP. The increase in FLC minimum inhibitory concentration for all isolates was evident and the majority developed resistance, whereas none isolated became less susceptible to BZP-BRP. Synergism was investigated by checkerboard method. BZP-BRP demonstrated synergy with FLC and indifference with AND for most isolates. CONCLUSIONS: In conclusion, the synergism observed with FLC suggests that BZP-BRP could be a possible therapeutic strategy for the treatment of infections related to FLC-resistant Candida sp. SIGNIFICANCE AND IMPACT OF THE STUDY: The indiscriminate use of antifungals results in the emergence of drug-resistant strains among previously susceptible populations. BZP-BRP can become an alternative for the treatment of persistent infections caused by Candida sp.

Imidazolium salts with antifungal potential against multidrug-resistant dermatophytes.

AIMS: To investigate the antidermatophytic action of a complementary set imidazolium salts (IMS), determining structure-activity relationships and characterizing the IMS toxicological profiles. METHODS AND RESULTS: The susceptibility evaluation of 45 dermatophytic clinical isolates, treated in vitro with eleven different IMS (ionic compounds) and commercial antifungals (nonionic compounds), was performed by broth microdilution, following the standard norm of CLSI M38-A2. All dermatophytes were inhibited by IMS, where the lowest minimum inhibitory concentration (MIC) values were observed for salts with n-hexadecyl segment in the cation side chain, containing either the chloride or methanesulfonate anion. 1-n-Hexadecyl-3-methylimidazolium chloride (C16 MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16 MImMeS) acted as fungicides, even in extremely low concentrations, wherein C16 MImMeS exerted this effect on 100% of the tested dermatophytes. Some of these IMS provoked evident alterations on the fungi cell morphology, causing a total cell damage of ≥ 70%. Importantly, none of the screened IMS were cytotoxic, mutagenic or genotoxic to human leucocyte cells. CONCLUSIONS: This report demonstrates for the first time the strong antifungal potential of IMS against multidrug-resistant dermatophytes, without presenting toxicity to human leucocyte cells at MIC. SIGNIFICANCE AND IMPACT OF THE STUDY: The expressive antifungal activity of IMS, combined with the in vitro nontoxicity, makes them promising compounds for the safe and effective treatment of dermatophytoses, mainly when this skin mycosis is unresponsive to conventional drugs.

Ultrasound biomicroscopy for biomechanical characterization of healthy and injured triceps surae of rats.

This work describes the use of ultrasound biomicroscopy (UBM) to follow up the degeneration-regeneration process after a laceration injury induced in the lateral gastrocnemius (LG) and soleus (SOL) muscles of rats. UBM (40 MHz) images were acquired and used for biomechanical characterization of muscular tissue, specifically using pennation angle (PA) and muscle thickness (MT). The animals were distributed in three groups: the variability group (VG; N=5), the gastrocnemius injured group (GG; N=6) and the soleus injured group (SG; N=5). VG rats were used to assess data variability and reliability (coefficients of variation of 9.37 and 3.97% for PA and MT, respectively). GG and SG rats were submitted to the injury protocol in the LG and SOL muscles of the right legs, respectively. UBM images of muscles of both legs were acquired at the following time points: before and after injury (immediately, 7, 14, 21 and 28 days). We observed an increase in PA for the non-injured leg 28 days after injury for both GG and SG rats (GG=10.68 to 16.53 deg and SG=9.65 to 14.06 deg; P<0.05). Additionally, MT presented a tendency to increase (GG=2.92 to 3.13 mm and SG=2.12 to 2.35 mm). Injured legs maintained pre-injury PA and MT values. It is suggested that a compensatory hypertrophic response due to the overload condition imposed to healthy leg. The results indicate that UBM allows qualitative and quantitative muscle differentiation among healthy and injured muscle at different stages after lesion.

Topographic trace-elemental analysis in the brain of Wistar rats by X-ray microfluorescence with synchrotron radiation.

Knowledge about the spatial distribution and the local concentration of trace elements in tissues is of great importance, since trace elements are involved in many biological functions of living organisms. However, there are few methods available to measure the spatial (two (three)-dimensional) elemental distribution in animal brain. X-ray microfluorescence with synchrotron radiation is a multielemental mapping technique, which was used in this work to determine the topographic of iron, zinc and copper in coronal sections of female Wistar rats of different ages. Young (14 days old) and middle-aged (20 months old) rats (n = 8) were analyzed. The measurements were carried out at the XRF beam line at the Synchrotron Light National Laboratory (Campinas, Brazil). Two-dimensional scanning was performed in order to study the tendency of elemental concentration variation. The acquisition time for each pixel was 10 s/step and the step size was 300 microm/step in both directions. It was observed that the iron distribution was more conspicuous in the cortical area, thalamus and bellow the thalamus. On the other hand, the zinc distribution was more pronounced in the hippocampus. The iron, copper and zinc levels increased with advancing age. Therefore, this study reinforces the idea that these elements are involved in the chemical mechanisms of the brain that induce some neurological diseases, since they are also present in high levels in specific areas of the brain, such as the hippocampus and the substantia nigra of patients with these disorders.

Fasting: a major limitation for resistance exercise training effects in rodents.

Protocols that mimic resistance exercise training (RET) in rodents present several limitations, one of them being the electrical stimulus, which is beyond the physiological context observed in humans. Recently, our group developed a conditioning system device that does not use electric shock to stimulate rats, but includes fasting periods before each RET session. The current study was designed to test whether cumulative fasting periods have some influence on skeletal muscle mass and function. Three sets of male Wistar rats were used in the current study. The first set of rats was submitted to a RET protocol without food restriction. However, rats were not able to perform exercise properly. The second and third sets were then randomly assigned into three experimental groups: 1) untrained control rats, 2) untrained rats submitted to fasting periods, and 3) rats submitted to RET including fasting periods before each RET session. While the second set of rats performed a short RET protocol (i.e., an adaptation protocol for 3 weeks), the third set of rats performed a longer RET protocol including overload (i.e., 8 weeks). After the short-term protocol, cumulative fasting periods promoted loss of weight (P<0.001). After the longer RET protocol, no difference was observed for body mass, extensor digitorum longus (EDL) morphology or skeletal muscle function (P>0.05 for all). Despite no effects on EDL mass, soleus muscle displayed significant atrophy in the fasting experimental groups (P<0.01). Altogether, these data indicate that fasting is a major limitation for RET in rats.

Anti-dermatophyte activity of Leguminosae plants from Southern Brazil with emphasis on Mimosa pigra (Leguminosae).

BACKGROUND: Intensive prophylactic use of antifungals leads to the increase of drug resistance and the need for new and more effective treatments are real. Plants from Leguminosae family are rich in flavonoids, for which numerous biological activities have been described, including antifungal effects. PURPOSE: To screen methanolic extracts from Leguminosae species looking for alternative sources for antifungal agents (anti-dermatophyte and anti-Candida) and their innocuity. METHODS: Antifungal activity was evaluated using the strains Candida albicans, C. krusei, C. glabrata, C. tropicalis, C. parapsilosis, Epidermophyton floccosum, Trichophyton mentagrophytes, T. rubrum and, Microsporum gypseum in the broth microdilution method. Later, the minimum inhibitory concentration (MIC) for Mimosa pigra, Eriosema heterophyllum, and Chamaecrista nictitans was determined. The most promising extract was fractionated and cytotoxicity and genotoxicity of the most active fraction were also assayed. RESULTS: Fungicide and/or fungistatic activity against dermatophyte strains were presented by 60% of the methanolic extracts assayed. M. pigra, E. heterophyllum, and C. nictitans methanolic extracts could inhibit dermatophyte strains at concentrations ranging from 1.9 to 1000µg/mL. M. pigra showed the lowest MIC values for a dichloromethane fraction (1.9µg/mL) without DNA damage at 10 and 50µg/mL and 100% of cell viability of human leukocytes. CONCLUSION: Our results indicate that methanolic extracts from Leguminosae plants are potential sources of antifungal compounds, mainly the extract and fractions from M. pigra. The dichloromethane fraction from M. pigra did not showed in vitro toxicity according to the applied assays.

Novel and conserved microRNAs in soybean floral whorls.

MicroRNAs (miRNAs) correspond to a class of endogenous small non-coding RNAs (19-24 nt) that regulates the gene expression, through mRNA target cleavage or translation inhibition. In plants, miRNAs have been shown to play pivotal roles in a wide variety of metabolic and biological processes like plant growth, development, and response to biotic and abiotic stress. Soybean is one of the most important crops worldwide, due to the production of oil and its high protein content. The reproductive phase is considered the most important for soybean yield, which is mainly intended to produce the grains. The identification of miRNAs is not yet saturated in soybean, and there are no studies linking them to the different floral organs. In this study, three different mature soybean floral whorls were used in the construction of sRNA libraries. The sequencing of petal, carpel and stamen libraries generated a total of 10,165,661 sequences. Subsequent analyses identified 200 miRNAs sequences, among which, 41 were novel miRNAs, 80 were conserved soybean miRNAs, 31 were new antisense conserved soybean miRNAs and 46 were soybean miRNAs isoforms. We also found a new miRNA conserved in other plant species, and finally one miRNA-sibling of a soybean conserved miRNA. Conserved and novel miRNAs were evaluated by RT-qPCR. We observed a differential expression across the three whorls for six miRNAs. Computational predicted targets for miRNAs analyzed by RT-qPCR were identified and present functions related to reproductive process in plants. In summary, the increased accumulation of specific and novel miRNAs in different whorls indicates that miRNAs are an important part of the regulatory network in soybean flower.

Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda).

Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this study shows that homology of visible colour cannot be assumed without identification of pigments.

Raman spectroscopy of coloured resins used in antiquity: dragon's blood and related substances.

Dragon's blood is a deep red resin which has been used for centuries by many cultures and much prized for it's rarity, depth of colour and alchemical associations. The original source of dragon's blood resin is believed to be Dracaena cinnabari from Socotra in Africa, but since mediaeval times there have been several alternatives from different geographical locations from the Canary Islands to the East Indies. Here, the Raman spectra of dragon's blood resins from Dracaena draco Liliacae trees growing in several different locations bordering the Mediterranean and Middle East are compared with the resins from alternative botanical sources such as Daemonorops draco, Dracaena cinnabari and Eucalyptus terminalis, which all generically come under the description of dragon's blood. Key vibrational spectroscopic marker bands are identified in the Raman spectra of the resins, which are suggested for adoption as a protocol for the identification of the botanical and possible geographical sources of modern dragon's blood resins. The Raman spectra of materials, which are falsely attributed to dragon's blood resin are also shown for comparison and identification purposes. Changes in the Raman spectra of genuine dragon's blood resin specimens arising from simple processing treatment during the preparation of the resins for sale are also identified, which suggests a possible attribution characteristic for unknown samples.

The squaric acid aggregate in mordenite investigated by Raman spectroscopy.

A more detailed investigation of the squaric acid aggregate within mordenite was undertaken with the use of Raman spectroscopy. The previous reported investigation was limited to the carbonyl stretching region in the IR. In the present work the entire region from 500 to 2000 cm(-1) was investigated, revealing rather substantial vibrational shifts of the oxocarbon ring modes in the aggregate. Comparison of such shifts with those observed for the squaric acid (H2Sq)/4,4'-bipyridine (Bipy) charge transfer (CT) complex reveals that the interaction is much stronger in the aggregate, a clear effect of the restrict geometry. On the other hand, the shifts observed for the CO stretching modes are rather modest. The comparison of the ring modes present in the Raman spectra of squaric acid, potassium hydrogen squarate, potassium squarate, H2Sq/Bipy and squaric acid aggregate in mordenite strongly suggests that in the latter hydrogen bonded species are present.

Stratified response to environmental stress in a polar lichen characterized with FT-Raman microscopic analysis.

The role of Antarctic epilithic lichens in the primary colonization of rocks and in the formation of soils is receiving attention because of the production of the stress-protective biochemicals needed to combat radiation, desiccation and extremes of temperature. Raman microscopy has been used here to study the encrustations produced at the interface between the rock substratum and Buellia spp. lichen thalli; in addition to whewellite, calcium oxalate monohydrate, the presence of weddellite, the metastable dihydrate form, was confirmed in the encrustations. An unusual pigmentation of the rock surface found on detachment of the lichen growths is identified as beta-carotene from its characteristic Raman bands at 1525, 1191, 1157 and 1003 cm(-1); normally, beta-carotene, which has been identified as a UV-radiation protectant, is found at the exposed upper surface of the biological organism. The interface between the detached lichen thalli and the rock also contains whewellite as the sole biomineralization product--which suggests a possible strategy for the formulation of weddelite in the growing Buellia spp. colony as an anti-desiccant.

Evaluation of a microtomography system with an X-ray microfocus tube.

The microfocus radiography system has been realized by means of a microfocus X-ray tube (maximum 160 kV), an image intensifier data collector and a five degree of freedom manipulation table. An 8-bit image acquisition PC-card and software were included to compose the microtomography system. To assemble the system, an image quantitative analysis was carried out by evaluation of the focal spot size, modulation transfer function of the system, and the 'defect discernibility curves'. The 2D microtomographies were carried out using the mean of 10 image central lines in each projection. Image processing techniques were also used to obtain better results. The image reconstruction program is based on a filtered backprojection algorithm using a special window. Images of various types of samples were carried out in order to verify the performance of the system.

Fasting: a major limitation for resistance exercise training effects in rodents

Protocols that mimic resistance exercise training (RET) in rodents present several limitations, one of them being the electrical stimulus, which is beyond the physiological context observed in humans. Recently, our group developed a conditioning system device that does not use electric shock to stimulate rats, but includes fasting periods before each RET session. The current study was designed to test whether cumulative fasting periods have some influence on skeletal muscle mass and function. Three sets of male Wistar rats were used in the current study. The first set of rats was submitted to a RET protocol without food restriction. However, rats were not able to perform exercise properly. The second and third sets were then randomly assigned into three experimental groups: 1) untrained control rats, 2) untrained rats submitted to fasting periods, and 3) rats submitted to RET including fasting periods before each RET session. While the second set of rats performed a short RET protocol (i.e., an adaptation protocol for 3 weeks), the third set of rats performed a longer RET protocol including overload (i.e., 8 weeks). After the short-term protocol, cumulative fasting periods promoted loss of weight (P<0.001). After the longer RET protocol, no difference was observed for body mass, extensor digitorum longus (EDL) morphology or skeletal muscle function (P>0.05 for all). Despite no effects on EDL mass, soleus muscle displayed significant atrophy in the fasting experimental groups (P<0.01). Altogether, these data indicate that fasting is a major limitation for RET in rats.