Synthesis of trehalose dimycolate (cord factor) by a cell-free system of Mycobacteriumsmegmatis

A 105,000 x g residue fraction of $\text{Mycobacterium}\text{smegmatis}$ contains an enzyme (acyl transferase) that transfers endogenous mycolic acid to trehalose monomycolate to yield trehalose dimycolate. This enzyme activity is stable to repeated freezing and thawing and is unaffected by the antimycobacterial drug, ethambutol. These results show that trehalose monomycolate is a direct precursor of trehalose dimycolate and suggest the presence of activated mycolic acids (acyl donor) in the cell-free system.     

Relationship between empirical water temperature and spring characteristics of swordtip squid (Uroteuthis edulis) caught in the eastern Tsushima Strait

ABSTRACT

We analysed the data of swordtip squid Uroteuthis edulis caught in the eastern Tsushima Strait, from April to September between 2012 and 2018, to consider the relationships among mantle length and body and gonad weights, associated with the estimated seasonal migratory routes and itineraries improved by the quantitative results of the tracer experiments. Our analyses have enabled us to reveal the characteristics of kensaki-type squid and the reasons for their appearance. We identified the kensaki-type U. edulis as male individuals, caught mainly in April–June, with long slender bodies, probably adapted to empirical duration of the cold sea water temperature in the Sea of Amakusa. Researchers and fishermen have referred to the seasonal migrating group including such males as a spring-migrating group. However, the females belonging to the spring-migrating group had no kensaki-type characteristics. Moreover, contrary to that achieved by the males, the female squid had acquired greater maturation in the spring than in any other seasons. These data demonstrated that the females continued to grow to maturation even in the cold sea waters, implying a different female strategy for reproduction from that of male squid. We are concerned that the commercially valuable kensaki-type squid may decrease in the future because the water temperature in the northern East China Sea is gradually rising, probably due to global climate change.     

Detection and characterization of extracellular phospholipase A2 in pleural effusion of patients with tuberculosis

Extracellular phospholipase A2 activity has been identified in pleural fluid of patients with tuberculosis. This enzyme is a calcium requiring protein and has a pH optimum of 10.0. The enzyme was inhibited by the active site-directed histidine reagent, rho-bromophenacyl bromide. Ionic and non-ionic detergents, or the sulfhydryl reagent dithiothreitol, caused loss of enzyme activity. When substrate specificity was tested using 2-[1-14C]linoleoyl phospholipids as substrates, phosphatidyl-ethanolamine was the best substrate, followed by phosphatidylserine and phosphatidylcholine. This phospholipase A2 showed high affinity for heparin, and was recognized by a monoclonal antibody raised against phospholipase A2 from human synovial fluid. These findings suggest that an extracellular phospholipase A2, which may belong to the 14K group II phospholipase A2 family, exists in the pleural fluid of patients with tuberculosis.     

Inhibitory effect of lactoferrin on hypertrophic differentiation of ATDC5 mouse chondroprogenitor cells

The skeleton is formed by two different mechanisms. In intramembranous ossification, osteoblasts form bone directly, whereas in endochondral ossification, chondrocytes develop a cartilage template, prior to osteoblast-mediated skeletogenesis. Lactoferrin is an iron-binding glycoprotein belonging to the transferrin family. It is known to promote the growth and differentiation of osteoblasts. In this study, we investigated the effects of bovine lactoferrin on the chondrogenic differentiation of ATDC5 chondroprogenitor cells. This mouse embryonic carcinoma-derived clonal cell line provides an in vitro model of chondrogenesis. Lactoferrin treatment of differentiating ATDC5 cells promoted cell proliferation in the initial stage of the differentiation process. However, lactoferrin treatment resulted in inhibition of hypertrophic differentiation, characterized by suppression of alkaline phosphatase activity, aggrecan synthesis and N-cadherin expression. This inhibitory effect was accompanied by sustained Sox9 expression, as well as increased Smad2/3 expression and phosphorylation, suggesting that lactoferrin regulates chondrogenic differentiation by up-regulating the Smad2/3-Sox9 signaling pathway.     

Differential giemsa staining of sister chromatids after extraction with acids

Chromosomes of Chinese hamster strain cells were air-dried on slides after BrdU substitution for two or three rounds of replication. The preparations were treated with 20% PCA at 55 degrees C for 20-30 min, or 5N HCl at 55 degrees C for 15-20 min. After staining with Giemsa, unifilarly BrdU-substituted chromatids stained faintly and bifilarly substituted chromatids stained darkly. Such a pattern of sister chromatid differential staining was confirmed by the examination of metaphase cells grown with BrdU for three rounds of replication.     

Enhancement of Galantamine HBr Skin Permeation Using Sonophoresis and Limonene-Containing PEGylated Liposomes

This study aimed to investigate the effect of low-frequency sonophoresis (SN) and limonene-containing PEGylated liposomes (PL) on the transdermal delivery of galantamine HBr (GLT). To evaluate the skin penetration mechanism, confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were employed. The application of SN led to more GLT penetration into and through the skin than GLT solution alone. The liposomes also improved GLT permeation, and 2% limonene-containing PL (PL-LI2%) exhibited the highest GLT permeation, followed by PL-LI1%, PL-LI0.1%, and PL. The CLSM images of PL-LI2% resulted in the highest fluorescence intensity of fluorescent hydrophilic molecules in the deep skin layer, and the rhodamine PE-labeled liposome membrane was distributed in the intercellular region of the stratum corneum (SC). PL-LI2% induced significant changes in intercellular lipids in the SC, whereas SN had no effect on intercellular lipids of the SC. DSC thermograms showed that the greatest decrease in the lipid transition temperature occurred in PL-LI2%-treated SC. SN might improve drug permeation through an intracellular pathway, while limonene-containing liposomes play an important role in delivering GLT through an intercellular pathway by increasing the fluidity of intercellular lipids in the SC. Moreover, a small vesicle size and high membrane fluidity might enhance the transportation of intact vesicles through the skin.     

Microfluidic systems: A new toolbox for pluripotent stem cells

Conventional culture systems are often limited in their ability to regulate the growth and differentiation of pluripotent stem cells. Microfluidic systems can overcome some of these limitations by providing defined growth conditions with user-controlled spatiotemporal cues. Microfluidic systems allow researchers to modulate pluripotent stem cell renewal and differentiation through biochemical and mechanical stimulation, as well as through microscale patterning and organization of cells and extracellular materials. Essentially, microfluidic tools are reducing the gap between in vitro cell culture environments and the complex and dynamic features of the in vivo stem cell niche. These microfluidic culture systems can also be integrated with microanalytical tools to assess the health and molecular status of pluripotent stem cells. The ability to control biochemical and mechanical input to cells, as well as rapidly and efficiently analyze the biological output from cells, will further our understanding of stem cells and help translate them into clinical use. This review provides a comprehensive insignt into the implications of microfluidics on pluripotent stem cell research.