The Chicago variant of clinical galactosemia

Summary A new variant of clinical galactosemia with two hitherto unidentified alleles on the transferase locus in one family is described. This new clinical variant of transferase has 25% of normal control activity in blood and in skin fibroblasts, and the patient accumulates galactose-1-phosphate in blood on an unrestricted galactose diet. Using starch gel electrophoresis on the hemolysate of the family members, a fast-moving transferase with mobility in between those of the normal control and of the Duarte variant is identified. This new allele is designated as (fast-moving Chicago variant). In addition, a second new allele was documented in this family by studying the instability of the transferase enzyme in hemolysates of family members at 50°C for various time intervals. This new allele is designated as (heat-labile Chicago variant). On the basis of the studies, the transferase genotype of this patients is thought to be a double heterozygote compound, /GALT^G.     

Translation of type C viral RNAs in Xenopus laevis oocytes: evidence that the 120,000-molecular-weight polyprotein expressed in Abelson leukemia virus-transformed cells is virus coded.

The genomic RNA of Abelson leukemia virus (AbLV) has been purified and translated in Xenopus laevis oocytes. The primary AbLV-specific protein synthesized is a polyprotein corresponding in molecular weight and immunological properties to a previously described p15 and p12 containing 110,000- to 130,000-molecular-weight polyprotein expressed in AbLV-transformed cells. In contrast, translation of woolly monkey sarcoma virus genomic RNA resulted in symthesis of a 55,000-molecular-weight polyprotein consisting of woolly helper virus p30, p15, and p12. These findings demonstrate the value of the X. laevis oocyte in vitro system for studies of translational products of replication-defective transforming viruses and establish the virus-coded nature of the nonstructural component of the 110,000- to 130,000-molecular-weight polyprotein expressed in AbLV-transformed cells.     

Primate retroviruses: envelope glycoproteins of endogenous type C and type D viruses possess common interspecies antigenic determinants.

The major 70,000- to 80,000-molecular-weight envelope glycoproteins of the squirrel monkey retrovirus, Mason-Pfizer monkey virus, and M7 baboon virus and the related endogenous feline virus, RD114, were isolated and immunologically characterized. Immunoprecipitation and competition immunoassay analysis revealed these viral envelope glycoproteins to possess several distinct classes of immunological determinants. These include species-specific determinants, group-specific antigenic determinants unique to endogenous primate type C viruses, and group-specific determinants for type D viruses such as Mason-Pfizer monkey virus and squirrel monkey retrovirus. In addition, a class of broadly reactive antigenic determinants shared by envelope glycoproteins of both type C viruses of the baboon/RD114 group and type D viruses of the Mason-Pfizer monkey virus/squirrel monkey virus group are described. Other mammalian oncornaviruses tested, including isolates of nonprimate origin and representative type B viruses, lacked these determinants. The demonstration of antigenic determinants specific to envelope glycoproteins of type C and type D primate viruses indicates either that these viruses are evolutionarily related or that genetic recombination occurred between their progenitors. Alternatively, endogenous type D oncornaviruses may be replication defective, and acquisition of endogenous type C viral genetic sequences coding for envelope glycoprotein determinants may be necessary for their isolation as infectious virus.     

Mitogens for murine embryo cell lines

The growth-promoting activities of fetal bovine serum, cortisol, phorbol myristate acetate, prostaglandin F2α, insulin, epidermal growth factor, and fibroblast growth factor were evaluated on four murine embryo cell lines (Swiss 3T3, Balb 3T3, M2, and C3H10T1/2). Each cell had an unique response spectrum to this collection of reported mitogens. Phorbol myristate acetate and prostaglandin F2α were active only on selected cell lines; cortisol was inactive on all four lines. Serum, epidermal growth factor, and fibroblast growth factor were able to stimulate cell division in all four lines, albeit to varying degrees for the different target cells.     

The activation of bovine Factor X by bovine Factor Xa

A steady-state kinetic analysis of the activation of bovine Factor X, by bovine Factor X_a, was undertaken. The activation was found to be dependent on the presence of divalent cations; Ca²⁺ showing the greatest stimulatory effect and Mn²⁺ exhibiting a lower degree of activity for this reaction. Although Sr²⁺ and Mg²⁺ were ineffective when present alone, each contributed synergistically to the activation rate at suboptimal levels of Ca²⁺. The effect of phospholipid (phosphatidylcholine:phosphatidylserine, 4:1, w:w) on the rate of activation and on the activation pathway was investigated. Phospholipid (PL) concentrations of up to 40 μm had no effect on the activation rate; whereas, concentrations of 40–180 μm were slightly inhibitory. In the absence of PL, the major product of the activation was Factor α-X_a, while in the presence of PL, lower-molecular-weight forms of Factor X (Factor β-X) and Factor X_a (Factor β-X_a were produced. At saturating levels of Ca²⁺, the K_{m app} for the activation, at pH 7.4 and 37 °C, in the absence of PL, was found to be 0.6 ± 0.1 μm and the V was 1.7 ± 0.3 mol Factor X cleaved min^?1 mol^?1 Factor X_a. The corresponding values, in the presence of 90 μm PL, were 1.4 ± 0.2 μm and 2.2 ± 0.2 mol Factor X cleaved min^?1 mol^?1 Factor X_a.     

Two distinct regulatory steps in cartilage differentiation

The effect of developmental stage on chondrogenic capacity in high-density cell cultures of chick embryonic wing bud mesenchyme is examined. Mesenchyme from stage 19 embryos forms aggregates of closely associated cells which do not form cartilage matrix, nor contain significant levels of type II collagen that are detectable by immunofluorescence, unless they are treated with dibutyryl cyclic AMP. Mesenchyme from stage 24 embryonic wing buds in high-density cell cultures will spontaneously form cartilage, as defined by electron microscopy and immunofluorescence with antibody to type II collagen. Cultures prepared from stage 26 wings form numerous aggregates which fail to accumulate an Alcian blue-staining matrix and which resemble mesenchyme cells morphologically. However, because these cells show considerable intracellular immunofluorescence for type II collagen, they are actually unexpressed cartilage cells. Several treatments, including exposure to dibutyryl cyclic AMP, ascorbic acid and an atmosphere of 5% oxygen, or mixture with small numbers of stage 24 wing mesenchyme cells, stimulate expression, as determined by the accumulation of an Alcian blue-staining matrix and an ultrastructurally recognizable cartilage matrix. Since the addition of similar numbers of differentiated cartilage cells does not stimulate expression of stage 26 cells, it is proposed that initial cartilage expression is dependent on a mesenchyme-specific influence which might be removed by cell dissociation. These studies demonstrate that there are at least two distinct transitions in cartilage differentiation: one involves the conversion of mesenchyme to unexpressed chondrocytes and the second involves mesenchyme-dependent expression of chondrogenic differentiation.     

Mitogenic property of the apical ectodermal ridge

While the apical ectodermal ridge (AER) is well known for its required role in the development of distal parts of the limb and for its ability to stimulate limb duplications, the mechanism of its action is unknown. In this study we use a culture system previously developed by M. Globus and S. Vethamany-Globus (1976, Differentiation6, 91–96) in which an AER grafted onto a high-density cell culture of limb mesenchyme stimulates the formation of an outgrowth. Time-lapse movies taken during the outgrowth period demonstrated no cellular activities other than cell division. Both the mitotic index and labeling index in the mesenchyme were significantly elevated under the AER as compared to that without AER, indicating that the AER provides a growth-promoting stimulus which increases the proportion of dividing cells. On the other hand, nonridge ectoderm had no detectable effect on the mitotic index. Treatment of cultures with cytosine arabinoside both inhibited DNA synthesis and prevented AER-induced outgrowth. These results demonstrate a mitogenic capacity of AER tissue and suggest that mesenchymal outgrowth requires this activity. The mitogenic property of the AER is considered in relation to limb outgrowth in situ.     

The Friesner Herbarium (BUT) of Butler University

The Friesner Herbarium (BUT) of Butler University is a collection of over 100,000 specimens built from the personal herbarium of Ray C. Friesner. He and other botanists at Butler amassed one of the largest and most complete collections of Indiana plants. Active exchange from the 1920’s through the 1940’s increased the holdings of plants from other states. Although the collection does not contain many type specimens, it is rich in vouchers from floristic and ecological studies conducted in the first half of the 20th century and published in the scientific journal,Butler University Botanical Studies.     

Endopeptidase-24.11, a Cell-Surface Peptidace of Central Nervous System Neurons, Is Expressed by Schwann Cells in the Pig Peripheral Nervous System

Endopeptidase-24.11 is a 90-kDa surface glycoprotein with the ability to hydrolyze a variety of biologically active peptides. Interest in this enzyme is based on the consensus that it may play a role in the termination of peptide signals in the central nervous system. In the present study, we have investigated the distribution of endopeptidase-24.11 in two nerves of the peripheral nervous system of newborn pigs: the sciatic, composed of a mixture of myelinated and nonmyelinated axons, and cervical sympathetic trunk in which greater than 99% of the axons are nonmyelinated. The endopeptidase was monitored enzymatically, as well as by immunoblotting and immunocytochemistry using mono- and polyclonal anti-endopeptidase antibodies. Endopeptidase-24.11 was detected in both the sciatic nerve and the cervical sympathetic trunk. Membrane preparations from sciatic nerve hydrolyzed 125I-insulin B-chain, and more than 50% of the activity was inhibited by phosphoramidon with an IC50 concentration of 3.2 nM. Moreover, a 90-kDa polypeptide was detected by immunoblotting of sciatic nerve membranes. The type of cells expressing the endopeptidase was determined by immunohistochemistry. In teased nerve preparations, these cells were identified morphologically as myelin- and non-myelin-forming Schwann cells. Endopeptidase-24.11 was also expressed by cultured Schwann cells from sciatic nerve and cervical sympathetic trunk maintained for 3 h in vitro. The presence of endopeptidase-24.11 on the Schwann cell surface raises the possibility of a potential role for the enzyme in nerve development and/or regeneration.