In vivo sequence variability of human immunodeficiency virus type 1 envelope gp120: association of V2 extension with slow disease progression.

According to the rate of depletion of CD4 cell counts, we grouped 12 cases of human immunodeficiency virus type 1 (HIV-1) infection as 6 rapid (21.0 to 33.8 cells per microl per month) and 6 slow (0.9 to 7.9 cells per microl per month) progressors and determined the individual viral quasispecies patterns by sequencing the genome region encoding the V1, V2, and V3 loops of envelope protein. Although the quasispecies structures varied widely from one individual to another, a strong correlation was observed between a low rate of disease progression and a high degree of genetic diversity of HIV-1. Furthermore, the V2 loop extension was observed specifically in individuals with slow or no disease progression, whereas basic amino acid substitutions in V3 characteristic of a viral phenotype shift from non-syncytium inducing to syncytium inducing were observed in patients with advanced stages of disease regardless of their rate of disease progression. Studies with recombinant viruses suggested that elongation of V2 potentially restricts the capacity of HIV-1 to replicate in macrophages. Thus, our results suggest the association of distinct sequence features of both V3 and V2 with particular patterns of disease progression. Elongation of the V2 loop may be a good predictor of slow disease progression, while basic substitutions of V3 without elongation of V2 are characteristic of rapid progression.     

Structural studies of the antigenic polysaccharide of Eubacterium saburreum, strain S29

The antigenic polysaccharide produced by Eubacterium saburreum, strain S29, is composed of (1→6)-linked β-d-glycero-d-galacto-heptopyranosyl residues, all of which are substituted with 6-deoxy-α-d-altro-heptofuranosyl groups at O-2.     

Specific subclones derived from a multipotential clone of rat anterior pituitary cells.

Several functional subclones of rat anterior pituitary cells were established from our 2A8 clone which apparently contains a heterogenous population of committed and uncommitted cells. On the basis of the hormones secreted into the culture media, as measured by radioimmunoassay, these subclones were divided into four categories, i.e., subclones which secrete (1) ACTH only, (2) prolactin only, (3) prolactin and GH or (4) ACTH, prolactin and GH. None of the subclones produced detectable amounts of thyrotrophic or gonadotrophic hormones. Subclones which secrete a single hormone have shown no change in the type of hormone produced, indicating that these subclones were each derived from a committed cell. The cells of all subclones exhibit a normal diploid karyotype and show good growth characteristics. The cells of the different subclones can be classified by phase contrast microscopy into four categories. However, no clear-cut ultrastructural features have been observed which can be correlated with the different categories of subclones. On the basis of the results a hypothesis is proposed relative to the functional cytodifferentiation of anterior pituitary cells.     

Synthesis of Acetyl Derivatives of 2-Amino-2-deoxy-1,6-dithio-D-glucose

From 2-anisylideneamino-1,3,4-tri-O-acetyl-2,6-dideoxy-6-S-acetyl-6-thio-β-D-glucopyranose, three derivatives of 2-amino-2-deoxy-1,6-dithio-D-glucose were prepared, i.e., 2-anisylidene-amino-3,4-di-O-acetyl-1,2,6-trideoxy-1,6-di-S-acetyl-1,6-dithio-β-D-glucopyranose, 2-amino-3,4-di-O-acetyl-1,2,6-trideoxy-1,6-di-S-acetyl-1, 6-dithio-β-D-glucopyranose hydrochloride and 2-acet-amido-3,4-di-O-acetyl-1,2,6-trideoxy-1-mercapto-6-S-acetyl-6-thio-β-D-glucopyranose; and some of their properties were described.     

The Preparation and Geometrical Isomerism of Substituted α-Methylthio-Cinnamic Acids

α-Methylthio-cinnamic acid and its substituted analogues (III) were synthesized from their respective β-aryl-α-thiopyruvic acids (II). In connection with the study on the tautomeric ene-thiol structure of β-aryl-α-thiopyruvic acids (II), 4-arylidenerl,3-oxathiolan-5-one (IV) were prepared from compounds II.     

Synthesis of 2-Acetamido-2-deoxy-1,6-dithio-d-glucose and its Derivatives

2-Acetamido-3,4-di-Oacetyl-2,6-dideoxy-6-S-acetyl-6-thio-d-glucopyranosyl chloride (III) was condensed with potassium thiolacetate, potassium ethylxanthate or thiourea to give three crystalline derivatives of 2-acetamido-2-deoxy-1,6-dithio-d-glucose. An attempt to prepare 2-acetamido-1,2,6-trideoxy-1,6-dimercapto-D-glucose (VII) from 2-acetamido-3,4-di-O-acetyl-1,2,6-trideoxy-1,6-di-S-acetyl-1,6-dithio-β-d-glucopyranose was described. 2-Acetamido-3,4-di-O-acetyl-1,2,6-trideoxy-1-mercapto-6-S-acetyl-6-thio-β-d-glucopyranose (VIII) was synthesized from the condensation product of III with thiourea.