Mixed colonies of Aspergillus niger and Aspergillus oryzae cooperatively degrading wheat bran.

In both natural and man-made environments, microorganisms live in mixed populations, while in laboratory conditions monocultures are mainly used. Microbial interactions are often described as antagonistic, but can also be neutral or cooperative, and are generally associated with a metabolic change of each partner and cause a change in the pattern of produced bioactive molecules. A. niger and A. oryzae are two filamentous fungi widely used in industry to produce various enzymes (e.g. pectinases, amylases) and metabolites (e.g. citric acid). The co-cultivation of these two fungi in wheat bran showed an equal distribution of the two strains forming mixed colonies with a broad range of carbohydrate active enzymes produced. This stable mixed microbial system seems suitable for subsequent commercial processes such as enzyme production. XlnR knock-out strains for both aspergilli were used to study the influence of plant cell wall degrading enzyme production on the fitness of the mixed culture. Microscopic observation correlated with quantitative PCR and proteomic data suggest that the XlnR Knock-out strain benefit from the release of sugars by the wild type strain to support its growth.

Cytosolic streaming in vegetative mycelium and aerial structures of Aspergillus niger.

Aspergillus niger forms aerial hyphae and conidiophores after a period of vegetative growth. The hyphae within the mycelium of A. niger are divided by septa. The central pore in these septa allows for cytoplasmic streaming. Here, we studied inter- and intra-compartmental streaming of the reporter protein GFP in A. niger. Expression of the gene encoding nuclear targeted GFP from the gpdA or glaA promoter resulted in strong fluorescence of nuclei within the vegetative hyphae and weak fluorescence in nuclei within the aerial structures. These data and nuclear run on experiments showed that gpdA and glaA are higher expressed in the vegetative mycelium when compared to aerial hyphae, conidiophores and conidia. Notably, gpdA or glaA driven expression of the gene encoding cytosolic GFP resulted in strongly fluorescent vegetative hyphae and aerial structures. Apparently, GFP streams from vegetative hyphae into aerial structures. This was confirmed by monitoring fluorescence of photo-activatable GFP (PA-GFP). In contrast, PA-GFP did not stream from aerial structures to vegetative hyphae. Streaming of PA-GFP within vegetative hyphae or within aerial structures of A. niger occurred at a rate of 10-15 µm s(-1). Taken together, these results not only show that GFP streams from the vegetative mycelium to aerial structures but it also indicates that its encoding RNA is not streaming. Absence of RNA streaming would explain why distinct RNA profiles were found in aerial structures and the vegetative mycelium by nuclear run on analysis and micro-array analysis.

Heterogeneity in liquid shaken cultures of Aspergillus niger inoculated with melanised conidia or conidia of pigmentation mutants.

Black pigmented conidia of Aspergillus niger give rise to micro-colonies when incubated in liquid shaken medium. These micro-colonies are heterogeneous with respect to gene expression and size. We here studied the biophysical properties of the conidia of a control strain and of strains in which the fwnA, olvA or brnA gene is inactivated. These strains form fawn-, olive-, and brown-coloured conidia, respectively. The ΔolvA strain produced larger conidia (3.8 µm) when compared to the other strains (3.2-3.3 µm). Moreover, the conidia of the ΔolvA strain were highly hydrophilic, whereas those of the other strains were hydrophobic. The zeta potential of the ΔolvA conidia in medium was also more negative when compared to the control strain. This was accompanied by the near absence of a rodlet layer of hydrophobins. Using the Complex Object Parametric Analyzer and Sorter it was shown that the ratio of individual hyphae and micro-colonies in liquid shaken cultures of the deletion strains was lower when compared to the control strain. The average size of the micro-colonies of the control strain was also smaller (628 µm) than that of the deletion strains (790-858 µm). The size distribution of the micro-colonies of the ΔfwnA strain was normally distributed, while that of the other strains could be explained by assuming a population of small and a population of large micro-colonies. In the last set of experiments it was shown that relative expression levels of gpdA, and AmyR and XlnR regulated genes correlate in individual hyphae at the periphery of micro-colonies. This indicates the existence of transcriptionally and translationally highly active and lowly active hyphae as was previously shown in macro-colonies. However, the existence of distinct populations of hyphae with high and low transcriptional and translational activity seems to be less robust when compared to macro-colonies grown on solid medium.

Estimation of the entropy based on its polynomial representation.

Estimating entropy from empirical samples of finite size is of central importance for information theory as well as the analysis of complex statistical systems. Yet, this delicate task is marred by intrinsic statistical bias. Here we decompose the entropy function into a polynomial approximation function and a remainder function. The approximation function is based on a Taylor expansion of the logarithm. Given n observations, we give an unbiased, linear estimate of the first n power series terms based on counting sets of k coincidences. For the remainder function we use nonlinear Bayesian estimation with a nearly flat prior distribution on the entropy that was developed by Nemenman, Shafee, and Bialek. Our simulations show that the combined entropy estimator has reduced bias in comparison to other available estimators.

Malignant ectomesenchymoma of the paranasal sinuses with proptosis.

PROBLEM: A 36-year-old woman presented with a feeling of pressure in the right orbit and proptosis of the right eye after a "common cold". METHODOLOGY: Computed tomography (CT) of the maxillofacial region revealed, and endoscopy confirmed, a mass in the right ethmoid sinus, eroding the lamina papyracea and extending into the orbit. Pathology of multiple biopsies revealed a nasal neoplasm composed of neuroectodermal and mesenchymal neoplastic elements, suggestive of a malignant ectomesenchymoma (MEM). Magnetic resonance imaging was used for MEM staging. Computed tomography of the chest and abdomen show no evidence of distant metastases. RESULTS: Due to the intracranial and intraorbital extension of the tumour, radical surgery was not an option. Appropriate chemotherapy (6 cycles of vincristine/ifosfamide/adriamycin and 2 cycles of vincristine/ifosfamide/cisplatin) and intensity-modulated radiation therapy were administered. CONCLUSION: Twenty-eight months after treatment, there was no evidence of residual or metastatic disease.

Sensitization to common aeroallergens in patients at an outpatient ENT clinic.

OBJECTIVES: The epidemiology of specific sensitization to inhalant allergens remains unknown in patients at tertiary rhinology clinics. We used skin prick testing (SPT) to assess sensitization to major aeroallergens in order to evaluate the prevalence of specific rhinologic diseases, the frequency of polysensitization and the relationship between nasal symptoms, nasal endoscopy parameters, diagnosis and sensitization. METHODS: A retrospective review of medical records was conducted at the ENT Department of the Catholic University Hospital in Leuven, Belgium. The study analyzed the medical data of patients with rhinologic symptoms suspected of having allergies. RESULTS: The study included 1326 patients with a mean age of 35 +/- 18 years (range: 3-88 years); 52.8% were males. Rhinitis without nasal abnormalities (42.1%), chronic rhinosinusitis without nasal polyps (16.5%) and nasal abnormalities (16.1%) were the most prevalent findings. About 31.6% of patients were sensitive to at least one allergen, and the most common aeroallergens were dermatophagoides pteronyssinus (62.1%) and grass pollen (53.2%). Polysensitization was found in 54.2%. The most prevalent clinical symptoms in allergic rhinitis patients were nasal obstruction, clear/watery nasal discharge, sneezing, postnasal drip and headache. Clear nasal discharge, sneezing, and itchy nose and eyes (p < 0.05 for all) were significantly higher in sensitized patients. In contrast, postnasal drip, headache and purulent nasal discharge were also observed in non-sensitized patients (p < 0.05 for all). CONCLUSIONS: At a rhinology clinic at a university ENT clinic, 31.6% of the patients had positive SPT results, mainly to house dust mites and grass pollen. Among sensitized patients, 54.2% were polysensitized.

Early infantile electroencephalography in patients with spina bifida*.

OBJECTIVE: The aim of this prospective study was to assess the prognostic value of electroencephalography in infants born with spina bifida.31 infants with spina bifida born between 2002 and 2007 at the Radboud Nijmegen University Medical Centre were evaluated and followed for 2½ years. Electroencephalography (EEG) was performed during the first 8 weeks after birth. RESULTS: EEG recordings were all within normal limits and showed no abnormalities. 3 of the 31 children showed mild mental disability and major physical disabilities at the age of 30 months. CONCLUSION: Single Infantile EEG recordings are of limited prognostic value for infants born with spina bifida. Serial EEG recordings in combination with other clinical or neurophysiological investigations might ameliorate the contributing predictive value of neonatal EEG.

Parents' personality and parenting stress in families of children with spina bifida.

BACKGROUND: Spina bifida (SB) can place parents at risk for increased levels of parenting stress. Little is known, however, about the role of parents' intrapersonal resources. Therefore, based on ideas of the Disability-Stress-Coping Model, relations between the severity of SB, parents' personality traits and parenting stress were examined. METHODS: Forty-six mothers and 37 fathers of children with SB (6-14 years) participated. Severity of SB (physical dysfunctions and cognitive functions), parental personality (Big Five) and parenting stress (Parenting Stress Index) were measured. Multiple regression analyses were performed. RESULTS: The severity of the child's physical dysfunctions was positively associated with parenting stress. Extraversion (mothers only), emotional stability and agreeableness (fathers only) were negatively related to parenting stress. In the final model, 64% of the variance in mothers' and 67% of the variance in fathers' levels of parenting stress was explained. Parents' personality traits explained the largest proportions of variance in parenting stress. CONCLUSION: Mobility, bladder and bowel dysfunctions in school-aged children with SB represent ongoing stressors for parents. Parents' intrapersonal resources of positive affectivity, however, are more important determinants of parental adjustment to SB than the child's physical dysfunctions.

Arnold-Chiari-II malformation and cognitive functioning in spina bifida.

Spina bifida is a multifaceted neurological condition with complex neuropsychological sequelae. The cognitive outcome in spina bifida has frequently been attributed to the severity of the hydrocephalus. However, because of complex neuropathology, the influence of hydrocephalus alone does not sufficiently explain the deficits in the cognitive profile in spina bifida. To date, little is known of the role of Arnold-Chiari-II malformation (ACM) in the cognitive profile of these patients. Aim of the current study is to delineate the specific contribution of the ACM in spina bifida by comparing children with ACM and those without ACM. 46 children between 6 and 15 years of age underwent a neuropsychological assessment covering intelligence and a wide range of cognitive functions, such as visuo-motor processing, attention, memory, word fluency and speed of information processing. Comparisons were made between patients with ACM (ACM+) and those without ACM (ACM-); all children with ACM+ also had hydrocephalus. Confounding effects of global cognitive impairment were excluded, such that groups were matched on verbal IQ. Because of complex neuropathology, which is inherent to spina bifida, the method applied was based on a comparison of cognitive profiles of the study group with profiles of patients with cerebellar damage and hydrocephalus found in the literature. Impaired visual analysis and synthesis, verbal memory, and verbal fluency, even after correction for global cognitive impairment, were observed in children with ACM. The hypothesis that in addition to impairment in visual analysis and synthesis, which are related to both hydrocephalus and ACM, specific deficiencies in verbal memory and fluency may be attributed to ACM is supported.