Neural crest cell migration in relation to extracellular matrix organization in the embryonic axolotl trunk

Temporal and regional aspects of early neural crest cell migration in relation to extracellular matrix (ECM) organization and distribution in the embryonic axolotl trunk were studied by light microscopy, TEM, and SEM. The dominating structure of the interstitial ECM is a complex network of fibrils, which are indicated by ruthenium red staining to consist of collagen in association with ruthenium red-positive components, probably including glycosaminoglycans. The ECM fibrils, which are largely used as substratum for locomotion by the crest cells, have a temporally and regionally specific organization and distribution. Increase in ECM fibrils on the neural tube, ahead of the crest cell front, is correlated with initiation of crest cell emigration, and it is suggested that the fibrils may stimulate this process by providing a suitable substratum for cell locomotion. An increase in ECM fibrils in extracellular spaces surrounding the crest cell population is correlated with an expansion of these spaces and with progressing crest cell migration into them. It is proposed that the spatial organization of the ECM fibrils influences crest cell shape and orientation during early migration.     

Evaluating the biodegradation of aromatic hydrocarbons by monitoring of several functional genes

Various microbial activities determine the effectiveness of bioremediation processes. In this work, we evaluated the feasibility of gene array hybridization for monitoring the efficiency of biodegradation processes. Biodegradation of ¹⁴C-labelled naphthalene and toluene by the aromatic hydrocarbon-degrading Pseudomonas putida F1, P. putida mt-2 and P. putida G7 was followed in mixed liquid culture microcosm by a preliminary, nylon membrane-based gene array. In the beginning of the study, toluene was degraded rapidly and increased amount of toluene degradation genes was detected by the preliminary gene array developed for the study. After toluene was degraded, naphthalene mineralization started and the amount of naphthalene degradation genes increased as biodegradation proceeded. The amount of toluene degradation genes decreased towards the end of the study. The hybridization signal intensities determined by preliminary gene array were in good agreement with mineralization of naphthalene and toluene and with the amount of naphthalene dioxygenase and toluene dioxygenase genes quantified by dot blot hybridization. The clear correlation between the results obtained by the preliminary array and the biodegradation process suggests that gene array methods can be considered as a promising tool for monitoring the efficiency of biodegradation processes.     

D1 protein degradation during photoinhibition of intact leaves a modification of the D1 protein precedes degradation

Illumination of intact pumpkin leaves with high light led to severe photoinhibition of photosystem II with no net degradation of the D1 protein. Instead, however, a modified form of D1 protein with slightly slower electrophoretic mobility was induced with corresponding loss in the original form of the D1 protein. When the leaves were illuminated in the presence of chloramphenicol the modified form was degraded, which led to a decrease in the total amount of the D1 protein. Subfractionation of the thylakoid membranes further supported the conclusion that the novel form of the D1 protein was not a precursor but a high-light modified form that was subsequently degraded.     

Regulation and function of innate and adaptive interleukin-17-producing cells

Interleukin-17 (IL-17)-mediated immune responses play a crucial role in the mucosal host defence against microbial and fungal pathogens. However, the chronic activation of IL-17-producing T helper cells can cause autoimmune disease. In addition, recent studies have highlighted key roles of innate cell-mediated IL-17 responses in various inflammatory settings. Besides inflammation, there have also been intriguing findings regarding the involvement of IL-17 responses in the pathogenesis of cardiovascular diseases and tumour formation. Here, we discuss the latest discoveries in regulation and function of innate and adaptive IL-17-producing cells.     

Mitochondrial DNA haplogroups in early-onset Alzheimer's disease and frontotemporal lobar degeneration

Background

Alleles of apolipoprotein E (APOE) are the major genetic risk factor for late onset Alzheimer's Disease (LOAD). Recently, an APOE splice variant that retains intron 3 (APOE-I3) was identified. To gain insight into the possible role of this isoform in LOAD, we quantified its expression in a cohort of 56 human brain specimens by using quantitative RT-PCR.

Results

We found that APOE-I3 generally represents a low percentage (< 0.5%) of overall APOE expression. However, in one specimen, the proportion of APOE-I3 was increased about ~13 fold. This specimen was unique in the cohort for possessing the minor allele of an intron 3 single nucleotide polymorphism (SNP), rs12982192. Additionally, an allelic expression imbalance study indicated that the rs12982192 minor allele was associated with increased APOE-I3 expression.

Conclusions

Overall, we interpret our results as suggesting that APOE-I3 represents a minor portion of APOE expression and that rs12982192 is associated with APOE intron 3 retention. Since the minor allele of this SNP is on the same haplotype as the minor allele of rs429358, which defines the APOE4 allele, we speculate that rs12982192 may reflect a modest loss of mRNA encoding functional APOE4.     

Evaluation of Bioremediation Treatments in a Shoreline-Simulating Microcosm

A microcosm test was designed to study the efficiency of bioremediation treatments at oil contaminated shorelines. The biodegradation in the hermetically closed microcosm was monitored by measuring the total cumulative inorganic carbon evolved during the bioremediation process. The effects of three different additives, medium-release methylene urea (MU) + apatite, fast-release MU + superphosphate, and a biosorbent, on the biodegradation of weathered crude oil (North Sea Brent) were evaluated at +10°C. All the additives significantly increased mineralization. The total amount of inorganic carbon evolved during the 10-week study was measured in the microcosm treated with oil, and with oil and medium-release MU + apatite, fast-release MU + superphosphate, and biosorbent. The amounts were 40,670,490, and 580 mg, respectively. The respirometric measurements were supported by microbiological determinations, ATP content in the sand, number of heterotrophic bacteria, and amount of biomass-C determined by the substrate-induced respiration method. Nutrient analysis indicated that biodegradation was nitrogen limited. The microcosm test proved to be suitable for comparing the effectiveness of different treatments in enhancing the biodegradation of crude oil-contaminated shores.