Detection of immunoglobulin heavy chain IgG3 polymorphism in wild mice with xenogeneic monoclonal antibodies

We have generated four xenogeneic rat antimouse IgG₃ monoclonal antibodies recognizing at least three different antigenic determinants (epitopes) on BALB/c IgG₃ molecules. These antibodies were used in solid-phase blocking radioimmunoassays for detection of the epitopes in sera of 40 inbred strains and 134 wild mice. These antibodies detect genetic polymorphism of IgG₃ isotype among wild mice even though there is no polymorphism found among 40 inbred strains tested (except X-chromosome-linked immunodeficient CBA/N strain which lacks IgG₃ molecules). An IgG₃ variant was also isolated from hybridomas derived from Mus spretus.Abbreviations Igh-C immunoglobulin heavy chain constant region - PVC polyvinyl chloride - RIA radioimmune assay - ELISA enzyme linked immunosorbent assay     

Human chromosomal assignments for 14 argininosuccinate synthetase pseudogenes: cloned DNAs as reagents for cytogenetic analysis

There are multiple, processed, dispersed pseudogenes for human argininosuccinate synthetase. Chinese hamster X human somatic cell hybrids were used to map DNA fragment groups corresponding to the single expressed gene and 14 pseudogene loci. Each chromosomal assignment was confirmed using hybrids containing very few human chromosomes and/or by demonstrating monosomic or trisomic dosage in human cell lines with chromosomal abnormalities. Pseudogenes were mapped to chromosomes 2cen-p25, 3q12-qter, 4q21-qter, 5 (two loci), 6, 7, 9p13-q11, 9q11-q22, 11q, 12, Xp22-pter, Xq22-q26, and Ycen-q11. DNA fragments from the expressed gene were mapped to 9q34-qter in agreement with the previous assignment for enzyme activity. A high-frequency restriction fragment length polymorphism mapped to 9q11-q22. The analyses emphasized the feasibility of using chromosomally abnormal human cell lines for confirmation and regionalization of gene-mapping assignments made using somatic-cell hybrids. Conversely, cloned DNA probes, once mapped and characterized, can be very valuable for determining the chromosomal composition of interspecies hybrids and the dosage of loci in human cells. The argininosuccinate synthetase cDNA is a convenient reagent for dosage analysis of 15 human loci on 11 different chromosomes. Improved reagents could be designed that would simplify Southern blot patterns by eliminating overlapping DNA fragments and providing a single DNA fragment for each locus.     

Combined effect of growth medium,age of cells and phase of sporulation on heat resistance and recovery of Hansenula anomala

Effects of two growth media, age of cells and phase of sporulation on heat resistance of Hansenula anomala were determined. Cells were grown on two solid media, McClary's acetate and V8 juice agars, at 21 ° C for 16 days. Heat resistance of cells was determined in 0.06 M potassium phosphate buffer at 48 ° C. Heat-stressed cells were plated on four recovery media: yeast extract-malt extract-peptone-glucose (YMPG), pH 7.0; YMPG, pH 3.5; YMPG containing 6% NaCl, pH 7.0; and YMPG containing 20% sucrose, pH 7.0. The composition of sporulation medium influenced the extent of sporulation and the relative heat resistance of sporulating cells. One-day-old cells were the most sensitive to heat. The heat resistance of cells was generally increased as the incubation time was extended to 16 days. Heat treatment caused a greater increase in sensitivity to NaCl than to sucrose or acid pH in recovery media. Young cells were more sensitive to NaCl than were older cells.     

Integument and sensory nerve differentiation ofDrosophila leg and wing imaginal discs in vitro

Summary An ultrastructural analysis is presented of the cuticular and neural structures formed by the prothoracic leg and wing imaginal discs of maleDrosophila melanogaster larvae during culture in vitro with 0.2 g/ml of -ecdysone. A pupal cuticle, and subsequently an imaginal cuticle with a well-defined epicuticle and a laminated endocuticle is formed. The ultrastructure of the epidermis and of cuticular structures such as bristles, trichomes, apodemes, and tracheoles is very similar to that found in situ. Dendrites and nerve cell bodies are formed in vitro, and sensory axons form nerve bundles similar to those of normal appendages in situ, despite their isolation from the central nervous system. It is concluded that at the ultrastructural level, differentiation in vitro closely parallels the normal course of development.     

Morphological changes in strains of Aspergillus flavus link ex fries and Aspergillus parasiticus speare related with aflatoxin production

Two strains ofAspergillus flavus Linkex Fr. and two strains ofA. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pané no. 247) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.)The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied,A. flavus NRRL 3251, lost completly the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations.A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.     

Metabolic adaptations in delayed skin flaps. Glucose utilization and hexokinase activity.

The distribution of glucose and hexokinase activity was determined in the epithelial tissue of delayed bipedicled skin flaps in guinea pigs. The periods of "delay" were 1, 3, 7, 14, or 21 days. The flap survival was maximal (100% of the flap) when the flap elevation was performed either 7 or 14 days following the "delay" procedure. When the flap elevation was performed 1, 3, or 21 days following the "delay" procedure, the result was partial necrosis. A differential distribution of epithelial glucose was found within the bipedicled flaps. The lowest glucose level (30% of normal) was at a distance of 2 to 3.5 cm from the end of the caudal pedicle during the first day after the "delay" procedure. This decreased glucose content recovered toward normal levels during the later part of the "delay" period. The bipedicled flaps exhibited increased hexokinase activity during the 3-week period of the "delay," and the responses of hexokinase activity and tissue glucose levels to the "delay" procedure were reciprocal in the caudal half of the flaps.     

Purification and properties of sucrose synthase from maize kernels

Sucrose synthase was purified from 22-day-old maize (Zea mays L.) kernels to homogeneity by the successive steps of ammonium sulfate fractionation, gel filtration through a Sephadex G-200 column, and affinity chromatography on a UDP-hexanol-amino-agarose column. The degree of purification is 42-fold and the yield is over 80%. Polyacrylamide gel electrophoretic techniques, sedimentation velocity, and gel filtration studies revealed that the enzyme has identical subunits and could assume tetrameric, octameric, and other higher aggregated forms which are dependent on the ionic species and ionic strength of the solution. All of the enzyme forms exhibit catalytic activity but show differences in their specific activities. In most cases, the tetramer is the predominant form and has the highest specific activity. It is thus concluded that the tetramer could be the native form of the enzyme. The subunit protein has a molecular weight of 88,000 and a blocked NH₂ terminus which is not available to Edman degradation. Some general properties and the amino acid composition of the enzyme are also reported.     

Long-Term Responses to Loss of Renal Mass: Tubular Changes: A Micropuncture Study of HCO3 Reabsorption by the Hypertrophied Proximal Tubule

In rats with renal failure produced by excision of one kidney and infarction of large portions of the other kidney, given a low calcium, high phosphorus diet for 2-3 weeks, GFR was reduced by 80 percent, the fractional excretion of sodium increased from 7 to 23 percent, that of bicarbonate from 16 to 23 percent and that of water from 4 to 13 percent. Single nephron GFR in the remaining nephrons was nearly doubled and end-proximal TF/P_In was depressed from 2.3 to 1.8, and proximal TF/P_HCO3 from 0.52 to 0.35, the latter figure corresponding to an increase of absolute proximal HCO₃ reabsorption from 1.7 to 3.5 nEq/min or from 2.8 to 3.2 Eq/L of single nephron glomerular filtrate. Acute parathyroidectomy had no influence on the fall of GFR or the rise of SNGFR in the remaining nephrons and failed to cause any significant changes in proximal tubular bicarbonate reabsorption. Parathyroidectomy, on the other hand, practically prevented the rise of the fractional excretion of sodium and of water and inverted the rise of the fractional excretion of bicarbonate to a fall. The data are interpreted to indicate that secondary hyperparathyroidism in renal failure impairs distal nephron bicarbonate and sodium reabsorption and, thus, contributes to the maintenance of sodium balance, but could possibly aggravate acidosis.     

黑河上游灌丛建群种中国沙棘自由授粉子代父本分析和花粉流

利用SSR分子标记对中国沙棘（Hippophae rhamnoides ssp. sinensis Rousi）自由授粉的种子进行父本分析,研究其子代的父本来源和花粉散布模式。结果显示：在80%的置信水平上,193个子代中有104个个体可以确定花粉来源;在20个确定的父本中,16个为中国沙棘,4个为肋果沙棘（H.neurocarpa S.W.Liu et T.N.He）。传粉格局分析结果显示,中国沙棘有效花粉散布范围为3~71 m,平均距离为20.4 m,2株母本分别有87.23%和78.95%的有效花粉来自距其30 m的范围之内,研究结果表明中国沙棘自然种群以近距离传粉为主。此外,在黑河上游沙棘杂交带中,中国沙棘子代中的肋果沙棘花粉平均贡献率达到14.84%,表明中国沙棘与肋果沙棘存在较高的种间当代花粉流。     

土牛膝碱（abidenine）的分离及结构测定

从土牛膝(Achyraanthes bidentata Bl.)的根中分离到一种新的生物碱——土牛膝碱(ubidenine),通过波谱方法测定出土牛膝碱的化学结构为5,6—二氢化—2,3,10,11—四甲氧基—二苯并[a,g]—喹嗪盐(1)。