Mutation in keratin 18 induces mitochondrial fragmentation in liver-derived epithelial cells

Microtubules (MTs) and microfilaments (MFs) are known to modulate mitochondrial morphology, distribution and function. However, little is known evidence about the role of intermediate filaments (IFs) in modulating mitochondria except desmin. To investigate whether or not the IFs regulate mitochondrial morphology, distribution, and function, we manipulated the IFs of cultured epithelial cells to express a mutant keratin 18 (K18). In contrast to the filamentous expression of wild K18, mutant K18 induced aggregation of K8/18, showing no fine IF network in the cells. In mutant K18-transfected cells, the mitochondria were fragmented into small spheroids, although they were observed as mitochondrial fibers in un-transfected or wild K18-transfected cells. Fluorescence recovery after photobleaching of fluorescence-labeled mitochondria was markedly less in the mutant K18-transfected cells, although a significant recovery was confirmed in wild K18-transfected cells. These findings suggest that the IFs are important for the maintenance of normal mitochondrial structures.     

A ten-year summary of reproductive parameters for ring-tailed lemurs at berenty, madagascar

From 1989 to 1998, 204 live births were recorded for ring-tailed lemurs (Lemur catta) at Berenty, Madagascar. Excluding unknown birth dates, the peak month of birth was September, with 82.0% (146/178) occurring during this period. The offspring sex ratio (1∶1.19) was not significantly different from 1∶1, and there was no association with the mother's age. The first births occurred at the ages of 2 to 4 yr. The annual birth rate was very low at the age of 2 yr (11.1%), but increased thereafter: to 50.0% at the age of 3 yr, and to 75–85% at the age of 4 or more years. Multiple births were very rare, since only three sets of twins and one set of triplets were recorded. As for the interbirth interval, a one-year interval was the most common (92.2%). Infant mortality within the first year was 37.7% (77/204). Neonatal mortality within the first month accounted for 31.2% of all infant dealths.     

Isotopic composition and morphology of living Globorotalia scitula: a new proxy of sub-intermediate ocean carbonate chemistry?

Abundance, isotopic composition and morphological imprints of the planktonic foraminifera Globorotalia scitula (Brady) were closely examined for possible use as a novel reconstruction tool of chemical environments in sub-intermediate depth seawater in the past. Based on the MOCNES plankton tow observation of dwelling depths of G. scitula and the isotopic compositions together with hydrochemistry data, the empirical relations between isotopic disequilibria in carbon (Δδ¹³C=δ¹³C_{G. scitula}−δ¹³C_DIC) and oxygen (Δδ¹⁸O=δ¹⁸O_{G. scitula}−δ¹⁸O_w) isotopes in the carbonate tests and the seawater δ¹⁸O and δ¹³C of dissolved inorganic carbon (DIC), respectively, are introduced. The morphological information such as pore density and porosity is also examined for significant relations to carbonate chemistry. Shell porosity is strongly correlated saturation state of calcite. The dissolution of living G. scitula tests may promote the observed isotopic differences as well as the increases in porosity. Δδ¹⁸O of G. scitula is found effectively to be linear function of both water temperature and calcite saturation state (Ω), and thereby temperature equation for G. scitula is provided, while Δδ¹³C of G. scitula is a linear function of only calcite saturation state.The equation was validated by using Globorotalia scitula collected by a sediment trap in intermediate water depths. Satisfactory agreements were found between observed and calculated Δδ¹⁸O from the empirical equations based on temperature and hydrochemistry data at sediment trap deployment site, indicating that the equation may be useful in paleo-environmental reconstruction of sub-intermediate water. The sediment trap observation further suggests that the abundance of G. scitula does not necessarily correspond to surface water productivity and to POC flux, but instead, it correlates well with the supply of fine organic matter, which appears to be a result of water convection. Thus, G. scitula may be an unambiguous and excellent paleo-environmental recorder for carbonate chemistry and for fine organic matter transport to the depths, if isotopic and morphological observations are combined.     

A Combined Enrichment and Aptamer Pulldown Assay for Francisella tularensis Detection in Food and Environmental Matrices

Francisella tularensis, a Gram-negative bacterium and causative agent of tularemia, is categorized as a Class A select agent by the Centers for Disease Control and Prevention due to its ease of dissemination and ability to cause disease. Oropharyngeal and gastrointestinal tularemia may occur due to ingestion of contaminated food and water. Despite the concern to public health, little research is focused on F. tularensis detection in food and environmental matrices. Current diagnostics rely on host responses and amplification of F. tularensis genetic elements via Polymerase Chain Reaction; however, both tools are limited by development of an antibody response and limit of detection, respectively. During our investigation to develop an improved culture medium to aid F. tularensis diagnostics, we found enhanced F. tularensis growth using the spent culture filtrate. Addition of the spent culture filtrate allowed for increased detection of F. tularensis in mixed cultures of food and environmental matrices. Ultraperformance liquid chromatography (UPLC)/MS analysis identified several unique chemicals within the spent culture supernatant of which carnosine had a matching m/z ratio. Addition of 0.625 mg/mL of carnosine to conventional F. tularensis medium increased the growth of F. tularensis at low inoculums. In order to further enrich F. tularensis cells, we developed a DNA aptamer cocktail to physically separate F. tularensis from other bacteria present in food and environmental matrices. The combined enrichment steps resulted in a detection range of 1–10⁶ CFU/mL (starting inoculums) in both soil and lettuce backgrounds. We propose that the two-step enrichment process may be utilized for easy field diagnostics and subtyping of suspected F. tularensis contamination as well as a tool to aid in basic research of F. tularensis ecology.     

Effects of internal diffusion on the lineweaver-Burk plots for immobilized enzymes

The effect of internal diffusion on the slope and the intercept of the LineweaverBurk plots for the immobilized enzyme was considered theoretically and it was found that the slope and the intercept are influenced not only by the dimensionless term M but also by the range of the dimensionless bulk substrate concentration ζ_b. The dependencies of the slope and the intercept on M and on the rate of ζ_b are shown graphically. Accurate estimations of M and the maximum velocity of the immobilized enzyme give the true, not apparent, Michaelis constant. It is shown that the linear correlations in the Lineweaver-Burk plots do not always coincide with the correlations for the estimation of M and the maximum velocity. It also is shown that large values of M may induce a serious error in the estimation of M with large values of ζ_b and in an estimation of the maximum velocity with small values of ζ_b.     

Insight into early diversification of leucine-rich repeat receptor-like kinases provided by the sequenced moss and hornwort genomes

Plant Molecular Biology - Identification of the subfamily X leucine-rich repeat receptor-like kinases in the recently sequenced moss and hornwort genomes points to their diversification into...     

The Waste Input-Output Approach to Materials Flow Analysis

Abstract: A general analytical model of materials flow analysis (MFA) incorporating physical waste input-output is proposed that is fully consistent with the mass balance principle. Exploiting the triangular nature of the matrix of input coefficients, which is obtained by rearranging the ordering of sectors according to degrees of fabrication, the material composition matrix is derived, which gives the material composition of products. A formal mathematical definition of materials (or the objects, the flow of which is to be accounted for by MFA) is also introduced, which excludes the occurrence of double accounting in economy-wide MFAs involving diverse inputs. By using the model, monetary input-output (IO) tables can easily be converted into a physical material flow account (or physical input-output tables [PIOT]) of an arbitrary number of materials, and the material composition of a product can be decomposed into its input origin. The first point represents substantial saving in the otherwise prohibitive cost that is associated with independent compilation of PIOT. The proposed methodology is applied to Japanese IO data for the flow of 11 base metals and their scrap (available as e-supplement on the JIE Web site).