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Abstract: The present study shows that hemocytic granular cells synthesize and secrete type IV collagen (ColIV) in the silkworm Bombyx mori (B. mori) and suggests that these cells play roles in the formation of basement membrane, the encapsulation of foreign bodies, and the metamorphic remodeling of the gut. The full- and partial-length cDNA of B. mori prolyl 4-hydroxylase α subunit (BmP4Hα) and B. mori ColIV (BmColIV) were cloned, respectively. In situ hybridization and immunocytochemistry on larval tissues and cells identified hemocytic granular cells as the cells that express mRNAs and proteins of both BmP4Hα and BmColIV. Immunohistochemistry and immunocytochemistry demonstrated that BmColIV was present in the basement membrane and in the secretory granules of granular cells, respectively. Granular cells in culture secreted BmColIV without accompanying the degranulation and discharged it from the granules when the cells were degranulated. Nylon threads were inserted into the hemocoel of larvae. Granular cells concentrated around the nylon threads and encapsulated them as a self-defense reaction. BmColIV was found to be a component of the capsules. Furthermore, the present study showed that actively BmColIV-expressing granular cells accumulated around the midgut epithelium and formed BmColIV-rich thick basal lamina-like structures there in larval to pupal metamorphosis. [Copyright &y& Elsevier]

Giant vesicles (GVs) are commonly used as artificial membranes and microcompartments in biochemical and biophysical studies. The efficiency and/or yield of their production can be strongly affected by the conditions and procedures used, and thus many protocols have been developed. A reverse-phase protocol has been used to prepare liposomes for decades, and is reported to be suitable for preparing GVs. By revisiting a reverse-phase (W/O/W emulsification) mechanism, in this study we verified how simply and efficiently GVs could be generated using the following alternative method. First, phospholipid/diethyl ether was mixed with an aqueous solution containing sucrose to form an emulsion, and the mixture was centrifuged. The resulting GVs together with tubular and sheet aggregates in the lower water phases could be purified by a second centrifugation after the addition of a glucose aqueous solution. This “reverse-phase/centrifugation” method provided a large amount of GVs of ∼20 μm in diameter from egg phosphatidylcholine as well as multiple lipid components. Spherical GVs were obtained in the presence of physiological salt concentrations (phosphate-buffered saline, PBS) when phosphatidylglycerol was included. The appearance of microdomains on the vesicle membranes may indicate that giant unilamellar vesicles (GUVs) can form through this process. [ABSTRACT FROM AUTHOR]

Abstract: Urease templated precipitation of silica synthesized by sol–gel chemistry produces a composite material allowing high urease activity. This study investigates the structural properties of the composite material that allow for the retention of the urease hydrolysis activity. Scanning (SEM) and transmission (TEM) electron microscopy reveal that the composite has a mesoporous structure composed of closely packed spherical structures ∼20–50nm in diameter. Brunauer–Emmett–Teller (BET) analysis revealed that the surface area and pore volume of the composite prepared under the conditions of 50mM urea and 25°C is relatively high (324m2/g and 1.0cm3/g). These values are equivalent to those of usual mesoporous silica materials synthesized from the self-assembly of triblock copolymers as organic templates. In addition, after encapsulating in a sol–gel silica matrix, urease retained high activity (∼90% of the activity compared with native urease). Our results suggest a new method for synthesizing mesoporous silica materials with highly tunable pore sizes and shapes under mild conditions. [Copyright &y& Elsevier]

Catalytic antibodies (38C2 and 84G3) were encapsulated in hybrid organic-inorganic sol-gel powder prepared from tetraethoxysilane (TEOS) and organoalkoxysilanes, then used to catalyze enantioselective aldol reactions. Sol-gel immobilization enhanced antibody stability with respect to the effect of temperature and organic solvent concentration. [Copyright &y& Elsevier]