Factors controlling the in vitro growth pattern of human microvascular endothelial cells

Monolayer cultures of endothelial cells of human dermal microvascular origin were exposed to a variety of culture conditions and in vitro differentiation of the cells assessed by light and electron microscopic examination. Restoration of a cytologic and fine structural appearance which resembled most closely that present in vivo was possible by raising the intracellular cAMP level. These cells formed junctional complexes seen in uncontracted microvessels and specialized attachment sites at their basal cell membrane, contained a complex network of bundled micro- and intermediate filaments and numerous Weibel-Palade bodies and accumulated electron-opaque deposits between the cells and the culture dish surface.     

Life cycle assessment of base–load heat sources for district heating system options

Purpose  

There has been an increased interest in utilizing renewable energy sources in district heating systems. District heating systems are centralized systems that provide heat for residential and commercial buildings in a community. While various renewable and conventional energy sources can be used in such systems, many stakeholders are interested in choosing the feasible option with the least environmental impacts. This paper evaluates and compares environmental burdens of alternative energy source options for the base–load of a district heating center in Vancouver, British Columbia (BC) using the life cycle assessment method. The considered energy sources include natural gas, wood pellet, sewer heat, and ground heat.     

KIF13A‐regulated RhoB plasma membrane localization governs membrane blebbing and blebby amoeboid cell migration

Membrane blebbing‐dependent (blebby) amoeboid migration can be employed by lymphoid and cancer cells to invade 3D‐environments. Here, we reveal a mechanism by which the small GTPase RhoB controls membrane blebbing and blebby amoeboid migration. Interestingly, while all three Rho isoforms (RhoA, RhoB and RhoC) regulated amoeboid migration, each controlled motility in a distinct manner. In particular, RhoB depletion blocked membrane blebbing in ALL (acute lymphoblastic leukaemia), melanoma and lung cancer cells as well as ALL cell amoeboid migration in 3D‐collagen, while RhoB overexpression enhanced blebbing and 3D‐collagen migration in a manner dependent on its plasma membrane localization and down‐stream effectors ROCK and Myosin II. RhoB localization was controlled by endosomal trafficking, being internalized via Rab5 vesicles and then trafficked either to late endosomes/lysosomes or to Rab11‐positive recycling endosomes, as regulated by KIF13A. Importantly, KIF13A depletion not only inhibited RhoB plasma membrane localization, but also cell membrane blebbing and 3D‐migration of ALL cells. In conclusion, KIF13A‐mediated endosomal trafficking modulates RhoB plasma membrane localization to control membrane blebbing and blebby amoeboid migration.     

Immunoperoxidase staining of glial fibrillary acidic (GFA) protein polymerized in vitro: An ultramicroscopic study

The unlabeled antibody peroxidase-antiperoxidase (PAP) method of Sternberger et al. has been employed at the ultramicroscopic level to stain filaments polymerized in vitro from aqueous extracts of multiple sclerosis (MS) plaques. The filaments were heavily decorated with antiserum to the glial fibrillary acidic (GFA) protein but not stained with serum absorbed with GFA protein, preimmunization serum, or anti-rat brain tubulin antiserum. Reassembled rat brain tubulin was heavily stained with antiserum to tubulin but was not stained with antiserum to the GFA protein. The present study provides direct morphological evidence that filaments polymerized in vitro from extracts of MS plaques contain the GFA protein.     

Ground beetle responses to patch retention harvesting in high elevation forests of British Columbia

The effect of a forest harvesting system whereby small (typically 0.1–2.0 ha) patches of standing timber are retained inside of harvests, was compared to conventional clearcutting for its effect on ground beetle assemblages. Two seasons of pitfall trapping entailed 46 451 trap days, and yielded 15 799 individuals of 28 species; abundance was dominated by four species comprising 92.4% of the catch. Most species were known to have wide geographic distributions in Canada and Alaska but many species seemed to respond to disturbance on a site-specific basis. Contrary to findings of similar studies, no species could be characterized as "mature-forest specialists", or "forest generalists". Forest patches and edge habitats immediately inside the forest canopy contained assemblages more closely related to mature forest than to cleared areas. Harvested areas with patches yielded catches distinct from typical clearcuts, based primarily on changes in abundance of one common species. Climatic regimes and landscape disturbance levels were the two important factors distinguishing our study from others, and we have suggested that these may influence the degree to which patches are an effective conservation tool.     

Varying immunological effects in mice of intranasal infection with different strains of influenza virus

Intranasal infection of CBA/Ca mice with a sublethal dose of A/2 Japan influenza virus 305/57 decreased the blastogenic response to concanavalin A and phytohemagglutinin, and less to lipopolysaccharide andEscherichia coli bacteria. This depression of the blastogenic responses could be transferred from infected donor mice by intravenous injection of 4×10⁷ spleen cells to otherwise untreated syngenic recipient mice. Similar infections with A/Victoria 3/75 and A/Texas 1/77 influenza virus strains caused less depressing effects. Less consistent results were seen with NMRI mice. No impairment of the antibody responses to unrelated protein antigen could be noted after such intranasal influenza infection. In contrast, the IgE antibody response was particularly increased after infection with Texas virus. Some deleterious effects of Victoria and Texas virus infections on the delayed hypersensitivity response to picryl chloride were seen in CBA mice but not in NMRI mice. This immune suppression by virus infection was not reflected by the defense against intraperitoneal infection withListeria monocytogenes andE. coli. In contrast, a small increase in resistance toListeria infection was recorded. The results of this study lend little support to the hypothesis that influenza infection impairs the immunological defense against a following bacterial infection, but may result in allergy.     

ATP level of a starving surface-bound and free-living marine Vibrio sp.

Abstract ATP levels of three marine isolates (a Vibrio sp., Serratia marcescens , and an unidentified rodshaped organism) were measured during nutrient-limiting conditions for free-living bacteria or cells adhered to a glass/liquid interface. In all strains there was a higher content of ATP per biovolume (numbers × cell volume) for cells starved at the glass/liquid interface compared with those in the bulk phase. Leakage from viable cells and the formation of a conditioning film are suggested only partly to explain the elevated levels of ATP per biovolume at the surface.     

Grass-Specific EPAD1 Is Essential for Pollen Exine Patterning in Rice

The highly variable and species-specific pollen surface patterns are formed by sporopollenin accumulation. The template for sporopollenin deposition and polymerization is the primexine that appears on the tetrad surface, but the mechanism(s) by which primexine guides exine patterning remain elusive. Here, we report that the Poaceae-specific EXINE PATTERN DESIGNER 1 (EPAD1), which encodes a nonspecific lipid transfer protein, is required for primexine integrity and pollen exine patterning in rice (Oryza sativa). Disruption of EPAD1 leads to abnormal exine pattern and complete male sterility, although sporopollenin biosynthesis is unaffected. EPAD1 is specifically expressed in male meiocytes, indicating that reproductive cells exert genetic control over exine patterning. EPAD1 possesses an N-terminal signal peptide and three redundant glycosylphosphatidylinositol (GPI)-anchor sites at its C terminus, segments required for its function and localization to the microspore plasma membrane. In vitro assays indicate that EPAD1 can bind phospholipids. We propose that plasma membrane lipids bound by EPAD1 may be involved in recruiting and arranging regulatory proteins in the primexine to drive correct exine deposition. Our results demonstrate that EPAD1 is a meiocyte-derived determinant that controls primexine patterning in rice, and its orthologs may play a conserved role in the formation of grass-specific exine pattern elements.