Two Loci Controlling Genetic Cellular Resistance to Avian Leukosis-Sarcoma Viruses

Female chickens known to be heterozygous for resistance to subgroups A and B of the avian leukosis-sarcoma viruses were mated to males known to be homozygously resistant to both. The progeny were assayed both on the chorioallantoic membrane (CAM) and in tissue culture for resistance to representative viruses of the A, B, and tentatively defined C subgroups. Segregation ratios of resistance to A and B subgroup viruses agreed with the previously suggested hypothesis of single-autosomal-recessive genes controlling resistance to each subgroup. Mixed infection on the CAM and replicate plate infection in tissue culture with subgroup A and B viruses showed that resistance to the A and B subgroups was inherited independently. Assays with viruses tentatively classified as subgroup C indicated that they were largely composed of a mixture of subgroup A and B viruses or of particles possessing the host range specificity of both. However, virus stocks of the subgroup C category, as well as some stocks classified as subgroup B, produced small numbers of pocks or foci on individuals known to be resistant to subgroup A and B viruses. It is suggested that these Rous sarcoma virus stocks carry between 1 and 10% of a true subgroup C virus.     

QTL mapping for tuberous stem formation of kohlrabi (<Emphasis Type="Italic">Brassica oleracea</Emphasis> var. <Emphasis Type="Italic">gongylodes</Emphasis> L.)

The tuberous stem of kohlrabi is an important quantitative trait, which affects its yield and quality. Genetic control of this trait has not yet been unveiled. To identify the QTLs controlling stem swelling of kohlrabi, a BC₁ population of 92 plants was developed from a cross of broccoli DH line GCP04 and kohlrabi var. Seine. A wide range of variation in tuberous stem diameter was observed among the mapping populations. We constructed a genetic map of nine linkage groups (LGs) with different types of markers, spanning a total length of 913.5 cM with an average marker distance of 7.55 cM. Four significant QTLs for radial enlargement of kohlrabi stem, namely, REnBo1, REnBo2, REnBo3, and REnBo4 were detected on C02, C03, C05, and C09, respectively, and accounted for the phenotypic variation of 59% for the stem diameter and 55% for the qualitative grading of tuberous stem in classes. Then, we confirmed the stability of identified QTLs using BC₁S₁ populations derived from the BC₁ plants having heterozygous alleles at the target QTL and homozygous kohlrabi alleles at the remaining QTLs. REnBo1and REnBo2 using 128 plants of BC₁68S₁ and 94 plants of BC₁43S₁, respectively, and REnBo3 and REnBo4 using 152 plants of BC₁57S₁ were detected at the same positions as the respective QTLs of the BC₁ population. Confirmation of QTLs in two successive generations indicates that the QTLs are persistent. The QTLs obtained in this study could be useful in marker-assisted selection of kohlrabi breeding, and to understand the genetic mechanisms of stem swelling and storage organ development in kohlrabi and other Brassica species.     

Evidence of intracellular and trans-acting differentiation-inducing activity in human promyelocytic leukemia HL-60 cells: its possible involvement in process of cell differentiation from a commitment step to a phenotype-expression step

We previously reported that human promyelocytic leukemia HL-60 cells, when treated with various inducers in magnesium-deficient medium, became committed to differentiate but did not express the differentiation-related phenotypes (Okazaki et al., J. Cell. Physiol., 131:50-57, 1987). In the present study we demonstrated the existence of an intracellular differentiation-inducing activity (int-DIA) in differentiation-committed phenotype-nonexpressing HL-60 cells by using cybrid formation between untreated HL-60 cells and cytoplasts from HL-60 cells treated in magnesium-deficient medium with 100 nM 1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3). Cell extracts from similarly treated HL-60 cells also showed int-DIA, which when added (10 mg total protein/ml) to culture of untreated HL-60 cells, could increase the percentages of nitroblue tetrazolium (NBT)- and nonspecific esterase (NSE)-positive cells from 1% to 53%, and from 0 to 32%, respectively. They also induced differentiation of human monoblastic leukemia U-937 cells and of human myeloblastic leukemia KG-1 cells but not of erythroleukemia K-562 cells. These results suggested that the int-DIA had a common effect on differentiation induction in several human myeloid cell lines and may be involved in inducing cells to proceed from a commitment to a phenotype-expression step during human myeloid cell differentiation.     

Relation of Rheological Properties with Starch Components among Glutinous,Sticky, Less-sticky Non-glutinous Rice Starches

Varoius piericidin analogues (PS-I, -II and -III in Fig. 2) were synthesized from three 4-acetoxy-6-formylpyridines by Wittig reaction to determine the structure-activity relationships. New type inhibitors, 5-alkenyl-2, 3-dimethoxy-4-hydroxy-6-methylpyridines (PS-IV) were synthesized by intramolecular cyclization.     

Moisture Sorption Isotherms of Various Tobaccos

The equilibrium moisture contents of sun-cured (Kroumougrad), flue-cured (Bright Yellow—4) and air-cured (Burley-21 and Matsukawa) tobaccos were measured over a relative humidity range from 5 to 80% at 20°C. The moisture sorption isotherms of tobaccos were of sigmoid type, and classified into two groups. In a lower humidity range below ca. 40% RH, the A group (Kroumougrad and BY-4) had a smaller moisture sorption capacity than B group (Burley-21 and Matsukawa), while in a higher humidity range above ca. 50% RH the former had a larger moisture sorption capacity than the latter. By extracting with water, the moisture content of BY-4 was increased in the lower humidity range, while it decreased in the higher humidity range. However, the moisture content of Matsukawa was scarecely changed by extracting it with water. These results suggest that the differences in equilibrium moisture content with the type of curing were due to the differences in contents of water soluble com- ponents. To control the hygroscopic properties of a tobacco, therefore, the influences of the addition of sucrose and glycerol on the equilibrium moisture content were quantitatively analysed. The moisture sorption capacity of tobacco was greatly different from its nitrogen sorption capacity. The specific surface area of tobacco calculated from moisture sorption isotherm was ca. 110 times larger than the specific surface area calculated from the nitrogen sorption isotherm. Both the nitrogen and moisture sorption data should be necessary for better understanding of the complicated sorption-desorption phenomena in tobaccos.     

Isolation and Characterization of Antitumor Lipopolysaccharide from Proteus mirabilis

Systematic isolation of the cell constituents of Proteus mirabilis RMS–203 was performed to find out localization of antitumor principle only in the lipopolysaccharide (LPS) layer of the cell wall fraction.

LPS with strong antitumor activity was extracted from P. mirabilis RMS–203 by phenol-water method followed by purification on DEAE-Sephadex A–50 column chromatography.

The main components of purified LPS were galactose, hexosamine, 2-keto-deoxy-octonic acid (KDO), myristic acid, β-hydroxymyristic acid and α,ε-diaminopimelic acid.

The minimal effective dose of LPS against Ehrlich solid carcinoma in mice was 0.1~1.0 μg/mouse. LD₅₀ in mice and pyrogenicity in rabbits were 28 mg/kg and 10^?3–10^?5 μg/rabbit, respectively.     

Regulation of cyclic longitudinal mechanical stretch on proliferation of human bone marrow mesenchymal stem cells

Mechanical stimulation is critical to both physiological and pathological states of living cells. Although a great deal of research has been done on biological and biochemical regulation of the behavior of bone marrow mesenchymal stem cells (MSCs), the influence of biomechanical factors on their behavior is still not fully documented. In this study, we investigated the modulation of mechanical stretch magnitude, frequency, and duration on the human marrow mesenchymal stem cells (hMSCs) proliferation by an in vitro model system using a mechanical stretch loading apparatus, and optimized the stretch regime for the proliferation of hMSCs. We applied 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl tetrasodium bromide (MTT) assay to estimate the overall proliferative effects of the stretch on hMSCs. We found that fibronectin coating increased adhesion to silicone chamber surface, however, it did not show significant effect on proliferation of hMSCs. A frequency of 1 Hz was more effective in stimulating hMSCs proliferation. At 1 Hz, 5% strain for 15, 30, 60 min, the significant increase of hMSCs proliferation was observed. Proliferation was enhanced at 1 Hz, 10% strain for 15, 30 min, while decreased for 60 min. At 1 Hz, 15% strain, 15 min stretch resulted in the decrease of proliferation, and 30 min and 60 min stretch showed an increased proliferation. Long time (12 and 24 h) strain application blocked the proliferation. These results indicate that mechanical stretch plays an important role in hMSCs growth and proliferation; an appropriate mechanical stretch regime could be a novel approach to promoting proliferation of hMSCs in vitro.     

Long-term follow-up of nasomaxillary epithelial inlay skin graft for the saddle nose

The nasomaxillary epithelial inlay skin graft described by H. D. Gillies in 1923 is one of the historical procedures of the twentieth century. Nowadays, this method has been thoroughly abandoned, and no long-term follow-up has been reported. In the Tokyo Metropolitan Police Hospital, between 1962 and 1983, 51 patients with saddle nose were treated using this procedure and a specially devised outer prosthesis. A follow-up study of these cases was attempted and that of nine cases was carried out. Six of nine patients have been using the outer prosthesis without any serious complications and are satisfied to varying extent. Three patients underwent further surgical treatment using autografts because of serious complications, which included full-thickness skin necrosis, refractory ulcer of the dorsum of nose, and anxiety about the unphysiological communication between the nasal and oral cavities.     

Gastric mucin hydrophobicity: effects of associated and covalently bound lipids, proteolysis, and reduction

The hydrophobic properties of gastric mucus glycoprotein were investigated using the fluorescent probe, bis(8-anilino-1-naphthalenesulfonate). The glycoprotein was subjected to removal of associated and covalently bound lipids, peptic degradation, and disulfide bridge reduction. Fluorescence titration data revealed the presence of 55 hydrophobic binding sites in the intact mucin molecule, 71 binding sites in the glycoprotein devoid of associated lipids, and 53 binding sites in the glycoprotein devoid of associated lipids and covalently bound fatty acids. Proteolytic digestion of the glycoprotein with pepsin essentially abolished the probe binding, while reduction of disulfide bridges resulted in glycoprotein subunits whose combined number of binding sites was about 3 times greater than that of the mucin polymer. The binding of the probe to mucus glycoprotein varied with the pH of the medium, being highest at pH 2.0 and lowest at pH 9.0. The results indicate that lipids contribute to the hydrophobic character of gastric mucin and that hydrophobic binding sites reside on the nonglycosylated regions of the glycoprotein polymer buried within its core.