High osmolarity glycerol response PtcB phosphatase is important for Aspergillus fumigatus virulence

Aspergillus fumigatus is a fungal pathogen that is capable of adapting to different host niches and to avoid host defenses. An enhanced understanding of how, and which, A. fumigatus signal transduction pathways are engaged in the regulation of these processes is essential for the development of improved disease control strategies. Protein phosphatases are central to numerous signal transduction pathways. To comprehend the functions of protein phosphatases in A. fumigatus, 32 phosphatase catalytic subunit encoding genes were identified. We have recognized PtcB as one of the phosphatases involved in the high osmolarity glycerol response (HOG) pathway. The ΔptcB mutant has both increased phosphorylation of the p38 MAPK (SakA) and expression of osmo‐dependent genes. The ΔptcB strain was more sensitive to cell wall damaging agents, had increased chitin and β‐1,3‐glucan, and impaired biofilm formation. The ΔptcB strain was avirulent in a murine model of invasive pulmonary aspergillosis. These results stress the importance of the HOG pathway in the regulation of pathogenicity determinants and virulence in A. fumigatus.     

Temporal and spatial distribution of young Brachyplatystoma spp. (Siluriformes: Pimelodidae) along the rapids stretch of the Madeira River (Brazil) before the construction of two hydroelectric dams

Monthly (April 2009 to May 2010) bottom‐trawl sampling for Brachyplatystoma species along the rapids stretch of the Madeira River in Brazil revealed that Brachyplatystoma rousseauxii larvae and juveniles were present in low abundances in all areas and during all hydrological periods. The presence of larvae and juveniles throughout the hydrological cycle suggests asynchronous spawning in the headwaters of the Madeira River.     

Effects of density and predation risk on leaf litter processing by Phylloicus sp.

The allochthonous detritus that accumulates in the substrate of streams is used by aquatic invertebrate shredders for shelter and food. Shredders are considered rare in tropical systems, and little information is available about the role of density effects and predation risk (associated with the perception of predators by prey) in relationship to the resources used by these organisms. The aim of this study was to examine experimentally the effects of increased predation risk and of the density of Phylloicus sp. (i.e. of two types of biological relationships) on the processing of the leaf litter of Nectandra megapotamica (Spreng.) Mez. Phylloicus sp. can use leaf litter for case building and as a food resource. The density effect was measured using four treatments that differed only in the number of individuals (one, two, three or four). A second experiment with five treatments was performed to test the risk of non‐lethal predation on detritus consumption (shelter and food) by Phylloicus sp. (T1: Caddisfly; T2: Mayfly; T3: Astyanax sp./fish; T4: Damselflies; T5: Stonefly). A single Phylloicus and one other organism (a potential predator blocked with 0.5 mm fine mesh) were placed in each tank (0.002 m³ volume). We observed a negative effect of density on per capita litter consumption (experiment 1). The low density of Phylloicus may be a natural factor that decreases intraspecific competition. In the presence of fish, Phylloicus showed the lowest amount of litter processing observed in the experiment, indicating top‐down control (experiment 2). In treatments that involved the presence of invertebrates (non‐predatory and predatory), Phylloicus showed the highest amount and an intermediate amount of leaf litter processing, respectively (experiment 2). This observation also suggests that the predation effect is more probable for specific predator–prey pairs. Population density and predation risk in Phylloicus may be important factors controlling leaf litter processing.     

Using network dynamic fMRI for detection of epileptogenic foci

Background

Epilepsy is one of the most prevalent neurological disorders. It remains medically intractable for about one-third of patients with focal epilepsy, for whom precise localization of the epileptogenic zone responsible for seizure initiation may be critical for successful surgery. Existing fMRI literature points to widespread network disturbances in functional connectivity. Per previous scalp and intracranial EEG studies and consistent with excessive local synchronization during interictal discharges, we hypothesized that, relative to same regions in healthy controls, epileptogenic foci would exhibit less chaotic dynamics, identifiable via entropic analyses of resting state fMRI time series.

Methods

In order to first validate this hypothesis on a cohort of patients with known ground truth, here we test individuals with well-defined epileptogenic foci (left mesial temporal lobe epilepsy). We analyzed voxel-wise resting-state fMRI time-series using the autocorrelation function (ACF), an entropic measure of regulation and feedback, and performed follow-up seed-to-voxel functional connectivity analysis. Disruptions in connectivity of the region exhibiting abnormal dynamics were examined in relation to duration of epilepsy and patients’ cognitive performance using a delayed verbal memory recall task.

Results

ACF analysis revealed constrained (less chaotic) functional dynamics in left temporal lobe epilepsy patients, primarily localized to ipsilateral temporal pole, proximal to presumed focal points. Autocorrelation decay rates differentiated, with 100 % accuracy, between patients and healthy controls on a subject-by-subject basis within a leave-one-subject out classification framework. Regions identified via ACF analysis formed a less efficient network in patients, as compared to controls. Constrained dynamics were linked with locally increased and long-range decreased connectivity that, in turn, correlated significantly with impaired memory (local left temporal connectivity) and epilepsy duration (left temporal – posterior cingulate cortex connectivity).

Conclusions

Our current results suggest that data driven functional MRI methods that target network dynamics hold promise in providing clinically valuable tools for identification of epileptic regions.

     

Expression of functional recombinant human growth hormone in transgenic soybean seeds

We produced human growth hormone (hGH), a protein that stimulates growth and cell reproduction, in genetically engineered soybean [Glycine max (L.) Merrill] seeds. Utilising the alpha prime (α') subunit of β-conglycinin tissue-specific promoter from soybean and the α-Coixin signal peptide from Coix lacryma-jobi, we obtained transgenic soybean lines that expressed the mature form of hGH in their seeds. Expression levels of bioactive hGH up to 2.9% of the total soluble seed protein content (corresponding to approximately 9?g?kg(-1)) were measured in mature dry soybean seeds. The results of ultrastructural immunocytochemistry assays indicated that the recombinant hGH in seed cotyledonary cells was efficiently directed to protein storage vacuoles. Specific bioassays demonstrated that the hGH expressed in the soybean seeds was fully active. The recombinant hGH protein sequence was confirmed by mass spectrometry characterisation. These results demonstrate that the utilisation of tissue-specific regulatory sequences is an attractive and viable option for achieving high-yield production of recombinant proteins in stable transgenic soybean seeds.     

Evaluation of the in vitro activity of dermaseptin 01, a cationic antimicrobial peptide, against Schistosoma mansoni

Schistosomiasis is a neglected tropical disease that remains a considerable public health problem worldwide. Since the mainstay of schistosomiasis control is chemotherapy with a single drug, praziquantel, drug resistance is a concern. Here, we examined the in vitro effects of dermaseptin 01 (DS 01), an antimicrobial peptide found in the skin secretion of frogs of the genus Phyllomedusa, on Schistosoma mansoni adult worms. DS 01 at a concentration of 100 μg/ml reduced the worm motor activity and caused the death of all worms within 48 h in RPMI 1640 medium. At the highest sublethal concentration of antimicrobial peptide (75 μg/ml), a 100% reduction in egg output of paired female worms was observed. Additionally, DS 01 induced morphological alterations on the tegument of S. mansoni, and a quantitative analysis carried out by confocal microscopy revealed extensive destruction of the tubercles in a dose-dependent manner over the concentration range of 50-200 μg/ml. It was the first time that an anthelmintic activity towards schistosomes has been reported for a dermaseptin.     

Effects of 24 weeks of progressive resistance training on knee extensors peak torque and fat-free mass in older women

This study examined the effects of resistance training (RT) on knee extensor peak torque (KEPT) and fat-free mass (FFM) in older women. Seventy-eight volunteers (67.1 ± 5.9 years old) underwent 24 weeks of progressive RT (RTG) while 76 (67.4 ± 5.9 years old) were studied as controls (CG). Dominant knee extension peak torque was assessed using an isokinetic dynamometer (Biodex System 3) and FFM measurements were performed by dual-energy x-ray absorptiometry. Muscle strength and FFM were evaluated before and after the intervention in all volunteers. Participants in the RTG trained major muscle groups 3 times per week during 24 weeks. Training load was kept at 60% of 1 repetition maximum in the first 4 weeks, 70% in the following 4 weeks, and 80% in the remaining 16 weeks, with repetitions, respectively, decreasing from 12, 10, and 8. A Split-plot analysis of variance was performed to examine between- and within-group differences, and the level of significance was accepted at p ≤ 0.05. It was observed that the RTG showed significant increases in KEPT (from 89.9 ± 21.8 to 102.8 ± 22.6 N·m; p < 0.05) and FFM (from 36.4 ± 4.0 to 37.1 ± 4.2 kg, p < 0.05). Appendicular FFM was also significantly increased after the intervention period in the RTG (13.9 ± 1.8 to 14.2 ± 1.9 kg, p < 0.05). None of these changes were observed for the CG. Consistent with the literature, it is concluded that a progressive RT program promotes not only increases in muscle strength, as evaluated by an isokinetic dynamometer, but also in FFM as evaluated by the DXA, in elderly women.