Change of the Structure of Cell Wall β-l,3-d-Glucan with the Growth of Neurospora crassa Cells

The chemical structure of cell wall β-d-glucans as well as the activities of lytic enzymes such as β-1,3-d-glucanase and β-1,6-d-glucanase changed during the growth of Neurospora crassa.

A dramatic change in the cell wall β-d-glucan structure was observed between cells of the middle logarithmic phase and ones of the late logarithmic phase. The ratio of 1,3-linked glucose residues to non reducing terminal glucose residues decreased from 85 to 55 and the ratio of gentiobiose as a hydrolysis product with exo-β-1,3-d-glucanase increased significantly between the two phases.

Two prominent peaks of β-1,3-d-glucanase as well as the β-1,6-d-glucanase activities appeared in the culture filtrate at different growth stages, the early logarithmic phase and the stationary phase. In the cell wall, β-d-glucosidase activity instead of the β-l,6-d-glucanase and β-1,3-d-glucanase activities was observed in the late logarithmic phase.     

Review of the fauna of Rotatoria,Cladocera, and Copepoda of the basin of the Anadyr’ River

The zooplankton composition is studied in the thermokarst, glacial and meteorite lakes, channels, former riverbeds, and hollows in the basin of Anadyr’. We found 174 taxa: 78, Rotatoria, 55, Cladocera, and 41, Copepoda. The most diverse is the lake fauna: 51 taxa of Rotatoria, 48, Cladocera, and 37, Copepoda. The thermokarst Lake Maiorskoe hosts 68 taxa: 31, Rotatoria, 14, Cladocera, and 23, Copepoda, wheras the cold ultraoligotrophic Lake El’gygytgyn features only one species of Cyclop of the group scutifer Cyclops neymanae Strel., and Rotatoria and Cladocera are present as allochtonous forms. The Copepoda illustrate the relations of the Anadyr’ fauna with those of Europe, North America, and Japan.     

Comparison of the 3′ Termini of Discrete Segments of the Double-Stranded Ribonucleic Acid Genomes of Cytoplasmic Polyhedrosis Virus, Wound Tumor Virus, and Reovirus

The 3' terminal nucleosides of the isolated components of double-stranded ribonucleic acids of reovirus, wound tumor virus, and cytoplasmic polyhedrosis virus were determined by labeling with tritiated sodium borohydride. All wound tumor virus and cytoplasmic polyhedrosis virus components appear to contain approximately equal amounts of U(OH) and C(OH) termini. Reovirus segments have essentially only C(OH) termini.     

Basis of the intrinsic flexibility of the Cε3 domain of IgE

Allergic reactions are triggered by the interaction between IgE and its high-affinity receptor, FcεRI. Various studies have mapped the interaction surface between IgE and its cellular receptors to the third constant domain of IgE (Cε3). The isolated Cε3 domain has been shown to exist as a molten globule, and the domain retains significant flexibility within the context of the IgE protein. Here we have analyzed the structural basis of the intrinsic flexibility of this domain. We have compared the sequence of the Cε3 domain to the sequences of other members of the C1 subset of the immunoglobulin superfamily and observed that Cε3 has an unusually high electrostatic charge and an unusually low content of hydrophobic residues. Mutations restoring Cε3 to a more canonical sequence were introduced in an attempt to derive a more structured domain, and several mutants display decreased levels of disorder. Engineered domains of Cε3 with a range of structural rigidities could serve as important tools for the elucidation of the role of flexibility of the Cε3 domain in IgE's biological functions.     

Easy stereoselective synthesis of 5α-estrane-3β,17α-diol, the major metabolite of nandrolone in the horse

5α-Estrane-3β,17α-diol is the major metabolite of nandrolone in horse urine. The presence of 5α-estrane-3β,17α-diol in female and gelding urines is prohibited by Racing Rules and its natural presence in male urine led regulation authorities to establish a concentration threshold of 45 ng/mL. This paper describes a rapid, simple and stereoselective synthesis of 5α-estrane-3β,17α-diol, providing horseracing laboratories with an essential reference material for their antidoping performance.     

Biological evaluation of 3'-O-alkylated analogs of salacinol, the role of hydrophobic alkyl group at 3' position in the side chain on the α-glucosidase inhibitory activity

Four analogs with 3′-O-alkyl groups (9a: CH₃, 9b: C₂H₅, 9c: C₁₃H₂₇ or 9d: CH₂Ph) instead of the 3′-O-sulfate anion in salacinol (1), a naturally occurring potent α-glucosidase inhibitor, were synthesized by the coupling reaction of 1,4-dideoxy-1,4-epithio-d-arabinitols (18a and 18b) with appropriate epoxides (10a-10d). These analogs showed equal or considerably higher inhibitory activity against rat small intestinal α-glucosidases than the original sulfate (1), and one of them (9d) was found more potent than currently used α-glucosidase inhibitors as antidiabetics. Thus, introduction of a hydrophobic moiety at the C3′ position of this new class of inhibitor was found beneficial for onset of stronger inhibition against these enzymes.     

Buchnera aphidicola,the endosymbiont of aphids,contains genes for four ribosomal RNA proteins,initiation factor-3, and the α-subunit of RNA polymerase

Buchnera aphidicola is a prokaryotic endosymbiont of the aphidSchizaphis graminum. With the polymerase chain reaction (PCR) and oligonucleotide primers to conserved regions, two DNA fragments of the endosymbiont -operon and L20 operon were amplified, cloned intoEscherichia coli, and their sequences were determined. The results indicated that the organization of the endosymbiont genes on these fragments was identical with that of the corresponding operons ofE. coli. The 1032 base pair (bp) fragment of the -operon contained the genes for small ribosomal subunit proteins S11 and S4, followed by the gene for the -subunit of RNA polymerase (-RNAP). The 702-bp fragment of the L20-operon contained the genes for initiation factor-3 (IF3) and large ribosomal subunit proteins L35 and L20. As in other prokaryotes, the genes of the -operon and the L20-operon were present as single copies in the genome ofB. aphidicola. Comparisons of the amino acid sequences of these proteins were consistent with the previously established close relationship betweenB. aphidicola andE. coli and a distant relationship to species ofBacillus.     

Studies on the mode of action of calciferol: Biological activity of 1α,24R,25-trihydroxyvitamin D3 in the chick

The biological activity of 1α,24R,25-trihydroxyvitamin D₃ [1α,24R,25(OH)₃D₃] was elevated in comparison to the hormonally active form of vitamin D₃, 1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃], in the rachitic chick in terms of its ability to (a) stimulate intestinal calcium absorption, (b) mobilize bone calcium, (c) induce intestinal calcium binding protein, (d) modulate the level of enzyme activity of the renal 25-OH-D₃-1-hydroxylase system, and (e) interact with the intestinal cystosol-chromatin receptor system for the 1α,25(OH)₂D₃ receptor system. In each of these assays, the relative ratio of activity of 1α,24R,25(OH)₃D₃ to 1α,25(OH)₂D₃was (a) 25–50, (b) ca. 20, (c) 10, (d) 50, and (e) 36%, respectively.     

Catalytic roles of the AMP at the 3′ end of tRNAs

Recent reports suggest that the ribosome retains considerable peptidyl transferase activity even when much of the protein of the ribosome is removed and further suggests that rRNA may be the peptidyl transferase. The work here suggests that the AMP residue at the 3 terminus of each tRNA has some catalytic activity both in the esterification reaction and in forming a pseudopeptide, AcGly, and further suggests that whatever peptidyl transferase is, it finds a cooperative substrate in the aminoacyl-AMP at the 3 terminus of tRNA.     

Characteristics of the Deoxyribonucleic Acid of Tφ3, a Bacteriophage for Bacillus stearothermophilus

It is shown that the individual strands of bacteriophage Tphi3 DNA are intact and that heat-denatured Tphi3 DNA forms a bimodal distribution in a neutral CsCl density gradient.     

Characterization of the Fourth α Isoform of the Na,K-ATPase

The Na,K-ATPase is a major ion transport protein found in higher eukaryotic cells. The enzyme is composed of two subunits, α and β, and tissue-specific isoforms exist for each of these, α1, α2 and α3 and β1, β2 and β3. We have proposed that an additional α isoform, α4, exists based on genomic and cDNA cloning. The mRNA for this gene is expressed in rats and humans, exclusively in the testis, however the expression of a corresponding protein has not been demonstrated. In the current study, the putative α4 isoform has been functionally characterized as a novel isoform of the Na,K-ATPase in both rat testis and in α4 isoform cDNA transfected 3T3 cells. Using an α4 isoform-specific polyclonal antibody, the protein for this novel isoform is detected for the first time in both rat testis and in transfected cell lines. Ouabain binding competition assays reveal the presence of high affinity ouabain receptors in both rat testis and in transfected cell lines that have identical K _D values. Further studies of this high affinity ouabain receptor show that it also has high affinities for both Na⁺ and K⁺. The results from these experiments definitively demonstrate the presence of a novel isoform of the Na,K-ATPase in testis. Received: 4 December 1998/Revised: 1 February 1999     

The Fluorescent Dye 3, 3′ Dihexyloxacarbocyanine Iodide Selectively Stains the Midpiece and Apical Region of the Heads of Murid Rodent Spermatozoa

Fluorescence microscopy of caudal epididymal spermatozoa stained with 3, 3′ dihexyloxacarbocyanine iodide (DiOC₆(3)) showed intense fluorescence along the concave surface of the apical hook of spermatozoa of Rattus species and along the upper concave margin of the sperm head in Mus musculus In the spermatozoa of Hydromys chrysogaster, Melomys cervinipes, and Pseudomys australis, the two ventral processes also fluoresced brightly. In P. australis, fluorescence in the apical hook of sperm heads was largely localized to its upper and lower surfaces. The sperm of N. alexis did not show consistent positive fluorescence. The localization of fluorescence in these spermatozoa after staining with DiOC₆(3) was mainly restricted to regions where a large accumulation of perinuclear theca material lies beneath the plasmalemma. The reason for this remains to be determined, but DiOC₆(3) may be useful for quickly demonstrating areas of abundant perinuclear thecal material in sperm heads of eutherian mammals by light microscopy.     

Synthesis and evaluation of bivalent, peptidomimetic antagonists of the αvβ3 integrins

Targeting the integrin α(v)β(3) by directly interfering with its function is considered to be an effective and non-cytotoxic strategy for the treatment of tumor. In this study, a series of bivalent analogs of peptidomimetic integrin antagonists IA 1 and IAC 2 were designed, synthesized, and evaluated for their ability to inhibit the integrin α(v)β(3). All the bivalent ligands exhibited increased potency compared to that of their monomeric counterparts for the integrin α(v)β(3) with low nanomolar range binding affinity. The best bivalent ligand 6 tested in the series has an IC(50)=0.09 nM evaluated by ELISA assay. We conclude that multivalency is providing a useful template for the development novel integrin α(v)β(3) antagonists as potential therapeutics.     

Comparison of Macular Integrity Assessment (MAIA ?), MP-3, and the Humphrey Field Analyzer in the Evaluation of the Relationship between the Structure and Function of the Macula

Purpose

This study was conducted in order to compare relationships between the macular visual field (VF) mean sensitivity measured by MAIA^TM (Macular Integrity Assessment), MP-3, or Humphry field analyzer (HFA) and the ganglion cell and inner plexiform layer (GCA) thicknesses.

Methods

This cross-sectional study examined 73 glaucoma patients and 19 normal subjects. All subjects underwent measurements for GCA thickness by Cirrus HD-OCT and static threshold perimetry using MAIA^TM, MP-3, or HFA. VF and OCT in the retinal view were used to examine both the global relationship between the VF sensitivity and GCA thickness, and the superior hemiretina and inferior hemiretina. The relationship between the GCA thickness and macular sensitivity was examined by Spearman correlation analysis.

Results

For each instrument, statistically significant macular VF sensitivity (dB) and GCA thickness relationships were observed using the decibel scale (R = 0.547–0.687, all P < 0.001). The highest correlation for the global (R = 0.682) and the superior hemiretina (R = 0.594) GCA thickness-VF mean sensitivity was observed by the HFA. The highest correlation for the inferior hemiretina (R = 0.687) GCA thickness-VF mean sensitivity was observed by the MP-3. Among the three VF measurement instruments, however, no significant differences were found for the structure-function relationships.

Conclusions

All three VF measurement instruments found similar structure-function relationships in the central VF.