Interfacial and micellar behavior of glucose lipid

Summary Glucose lipid of notable surfactant properties was produced by using hydrocarbon assimilating bacterium of the bacterial strain MM1. Its surface active properties were notable in spite of ,-hydrophilic and bulky molecule. The critical micelle concentration (cmc) was small (0.165 M); surface and interfacial tension for hexadecane at 0.1 % (pH 7.35) solution, 24.6 and 13.3 mN/m, respectively. The emulsifying action was excellent and comparable to those of rhamnolipids. The micelle has the outer radius. 28.5 Å and inner core, 6.7 Å on the basis of the concentric spherical shell model by means of the small angle X-ray solution scattering measurement.Dedicated to Professor Fritz Wagner on the occasion of his 65th birthday.     

Body-specific proliferation of adult precursor cells in Xenopus larval epidermis

Cell proliferation was examined in the back and tail epidermis of larval Xenopus laevis using bromodeoxyuridine (BrdU). The BrdU labeling index of the back epidermis increased temporally at stage 59, followed by a rapid decrease to the same level as at stage 51. The temporal increase in cell proliferation of the back epidermis produced a new epidermal layer composed of basal cells. In vitro analysis showed that tri-iodothyronine (T₃) promotes cell proliferation of basal cells but suppresses that of skein cells. Immunohistochemical studies showed that the newly formed basal cell layer functions as adult precursor cells which produce the adult epidermal cells. In contrast to the back epidermis, the labeling index of the tail epidermis decreased from stage 57. However, when the tail skin was transplanted to the back area, cell proliferation in the tail epidermis increased to the same level as that of the normal back epidermis. Cell proliferation of the back epidermis was not suppressed by transplanting the skin to the tail area. These results suggest that some promoting factors are produced in the body region and regulate the number of adult precursor cells, which determine the developmental fate of the larval skin.     

A target protease activity of serpins in insect hemolymph

Two zymogens of the serine enzymes (prophenoloxidase activating enzyme and BAEEase, an enzyme hydrolyzing ethyl ester), which are thought to be components of prophenoloxidase cascade in silkworm (Bombyx mori) plasma, were activated through the action of microbial cell wall components. The two active enzymes of the zymogens were studied with regard to the regulation of their activities by two endogenous serpins (silkworm anti-trypsin and silkworm anti-chymotrypsin).

BAEEase activity was shown to be inactivated by silkworm antitrypsin, whereas the inactivation of prophenoloxidase activating enzyme by either of silkworm antitrypsin and silkworm antichymotrypsin could not be demonstrated under the experimental conditions.     

Euphausia superba dominates in the diet of Adélie penguins feeding under fast sea-ice in the shelf areas of Enderby Land in summer

Adélie penguins Pygoscelis adeliae in Enderby Land, Antarctica feed mainly on Euphausia superba during the chick rearing season in shelf areas where fast sea-ice remains: indicating that E. superba is abundant under the fast sea-ice in these areas. The shelf areas in Enderby Land, therefore, are unique since the previous studies of Adélie penguin diet in Ross Sea, Adélie Land and Prydz Bay show that E. crystallorophias is the most abundant krill species in shelf areas in general.     

Suppressive effect of spinach extract on the formation of melanin in B16 mouse melanoma cells

A non-dialyzable extract of fresh spinach leaves exhibited a strong antioxidant activity towards oxidation of linoleic acid and suppressed the melanin formation of a mouse melanoma cell line, B16 melanoma 4A5, without any significant effect on the proliferation of cells.     

cDNA Cloning and Expression of the Plastidic Copper/Zinc-Superoxide Dismutase from Spinach (Spinacia oleracea L.) Leaves

A cDNA clone for copper/zinc-superoxide dismutase (Cu/Zn-SOD)was isolated from spinach (Spinacia oleracea L.) leaves. Itsnucleotide sequence showed that it codes for a precursor polypeptideof 222 amino acids, including the NH₂-terminal 68-residue extensionwhich corresponds to a plastidic transit peptide. Northern hybridization,using plastidic and cytosolic Cu/Zn-SOD cDNAs as the probes,revealed that these two genes are differentially expressed inthe roots and leaves of spinach. ¹Present address: Department of Biochemistry and Microbiology,Cook College, Rutgers University New Brunswick, NJ 08903-0231,U.S.A.     

Possible Involvement of Abscisic Acid in Increases in Activities of Two Vacuolar H+-Pumps in Barley Roots under Aluminum Stress

Levels of abscisic acid (ABA) in barley roots increased upontreatment with AlCl₃. Treatment with AlCl₃ or ABA increasedboth ATP-dependent and PP_i-dependent H⁺-pumping activities intonoplast-enriched membrane vesicles. Increase in the H⁺-pumpingactivities caused by aluminum stress could result from increasedlevels of ABA. ¹Present address: Department of Botany, Faculty of Science,Hirosaki University, Hirosaki, Aomori, 036 Japan     

A Novel Method for Generating Nested Deletions Using the in Vitro Bacteriophage T3 DNA Packaging System

To sequence a DNA segment inserted into a cosmid vector underthe directed sequencing strategy, we established a simple andrapid method for generating nested deletions which uses thein vitro packaging system of bacteriophage T3 DNA. The principleis based on the previous finding that this system can translocateany linear double-stranded DNA up to 40 kb into the phage capsidin a time-dependent manner and the encapsulated DNA becomesDNase-resistant. For this purpose, we constructed a cosmid vectorthat carries two different antibiotic selection markers at bothsides of the multiple cloning site, and after insertion of aDNA segment, the clone was linearized by -terminase at the cossite. After the packaging reaction in vitro followed by DNasetreatment, the encapsulated DNA was introduced into Escherichiacoli cells to give clones with unidirectional deletions by differentialantibiotic selection. Restriction and sequence analyses of deletionclones demonstrated that an ordered set of clones with nesteddeletions, ranging from less than 1 kb to 25 kb, was createdfrom either the end of the DNA segment. Thus, nested deletionclones that cover the entire region of a 40-kb cosmid insertcan be obtained by a single packaging reaction, and its restrictionmap can be simultaneously obtained.