Cross-linking and O-acetylation of newly synthesized peptidoglycan in Staphylococcus aureus H

Staphylococcus aureus H growing exponentially was labelled with N-acetyl[14C]glucosamine, which became incorporated into the peptidoglycan. The portion of peptidoglycan not linked to teichoic acid (60-75% of the whole) was degraded with Chalaropsis muramidase to yield disaccharide-peptide monomers and dimers, trimers and oligomers formed by biosynthetic cross-linking of the monomers. The degree of O-acetylation of these fragments was also examined. Pulse-chase experiments showed that the proportion of label initially in the monomer fraction immediately after the 1 min pulse declined rapidly during a 3 min chase, while the oligomer fraction (fragments greater than trimer) gained the radioactivity proportionately. The radioactivity of the dimer and trimer fractions remained virtually unchanged. At 4 min after the commencement of labelling (i.e. approx. one-tenth of a generation time) final values had been reached. The O-acetylation of all fragments had achieved final values even at 1 min, except for the monomer fraction, which showed an increase from 40% to 60% during the first 3 min of chase. Although O-acetylation was clearly a very rapid process, no O-acetylated peptidoglycan lipid-intermediates could be detected.     

A comparison of Hordeum bulbosum-mediated haploid production efficiency in barley using in vitro floret and tiller culture

Summary A high efficiency of Hordeum bulbosum-mediated haploid production in barley has been achieved using a floret culture technique in which florets pollinated with Hordeum bulbosum are cultured on modified N₆ media containing 0.5 mg/l kinetin and 1.2 mg/l2,4-D. Cultures were maintained at 25 °C with a 16 h photoperiod for 9 days before embryo rescue. In a comparison of haploid production efficiency using five F₁ hybrids from winter x winter and winter x spring barley crosses, 41.6 haploid plants/100 florets pollinated were produced using floret culture. Using detached tiller culture, 13.5 haploid plants/100 florets pollinated were produced. Higher efficiencies achieved with floret culture are attributed to the formation of larger, differentiated embryos. Such embryos lead to higher frequencies of plant regeneration. The F₁ from a winter x winter cross was inferior in haploid production compared to F₁s from winter x spring crosses. No genotype x technique interaction was observed.Oregon Agricultural Experiment Station Technical Paper No. 8653     

Proposed field evaluation of a rabies recombinant vaccine for raccoons (Procyon lotor): site selection, target species characteristics, and placebo baiting trials

Prior to a limited field application of an orally-administered vaccinia-rabies glycoprotein (V-RG) recombinant virus vaccine for wildlife, background data were obtained for the proposed site on Parramore Island, Virginia (USA). Mammalian target and nontarget species, potentially at risk for exposure to vaccine were inventoried. Placebo baiting trials with a fishmeal polymer bait resulted in high bait disturbance (88 to 100%), primarily by raccoons (Procyon lotor), with infrequent visitation and no evidence of bait consumption by deer (Odocoileus virginianus), small mammals or avian species. Definitive bait acceptance rates by raccoons (indicative of bait ingestion) were difficult to accurately determine based exclusively on premolar and vibrissae samples collected antemortem from live-trapped raccoons for tetracycline and rhodamine B biomarker analyses, respectively. Bait acceptance rate was more accurately determined during a pilot baiting trial conducted on North Island, South Carolina, when mandibles (postmortem samples) were examined for tetracycline incorporation. Parasitologic findings in raccoons on Parramore Island included Hepatozoan procyonis, Phagicola angrense and Physaloptera rara and a variety of incidental microscopic lesions, and provided baseline pathological data for comparison subsequent to V-RG vaccine application. A population density estimate of one raccoon/2.7 ha was calculated using mark-recapture data for comparison after vaccine deployment. Limited reproductive data, including estimates of pregnancy rates by palpation, the number of live kits/litter live-trapped with previously pregnant raccoons or observed in the dens of radio-collared raccoons, was gathered to assess the effect of proposed oral vaccination with V-RG vaccine. Home ranges were assessed by radio-telemetry of 15 raccoons; all radio-collared raccoons currently reside on Parramore Island.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heterogeneity of 14S and 30S dynein ATPase activities with respect to activation by calmodulin

Demembranated cilia of Tetrahymena pyriformis were extracted with KCl or Tris-EDTA and the crude dyneins from each resolved by sucrose density gradient sedimentation into 14S-K, 30S-K, 14S-E and 30S-E dyneins, respectively. The calmodulin activation ratio (ATPase activity in presence of added calmodulin/ATPase activity in absence of added calmodulin) did not vary across the 30S dynein fractions regardless of the method of extraction nor did it vary across the 14S-E region. However, in going from the “heavy” fractions to the “light” fractions of the 14S-K region, it increased markedly. The concentration of calmodulin required for half-maximal activation did not differ appreciably in the “light” versus the “heavy” fractions of the 14S-K region, suggesting that the affinity for calmodulin does not vary in these fractions. SDS-polyacrylamide gel electrophoresis studies showed the presence of several polypeptides that varied in a systematic fashion across the 14S-K region and hence may be involved in regulating the sensitivity of 14S-K dynein ATPase activity to added calmodulin.     

Production of alcohol from Jerusalem artichokes by yeasts

Various yeasts such as several strains of Saccharomyces diastaticus, S. cerevisiae, and Kluyveromyces fregilis were investigated for their ability to ferment the carbohydrates from Jerusalem artichokes to alcohol. Juice extracted of the carbohydrates. Fermentation was also carried out with raw artichokes without prior juice extraction. Result indicate that this row material has good potential for fuel alcohol production by fermentation.     

Protein-RNA crosslinking in Escherichia coli 30S ribosomal subunits. Identification of a 16S rRNA fragment crosslinked to protein S12 by the use of the chemical crosslinking reagent 1-ethyl-3-dimethyl-aminopropylcarbodiimide.

1-ethyl-3-dimethyl aminopropylcarbodiimide (EDC) was used to cross-link 30S ribosomal proteins to 16S rRNA within the E. coli 3OS ribosomal subunit. Covalently linked complexes containing 30S proteins and 16S rRNA, isolated by sedimentation of dissociated crosslinked 30S subunits through SDS containing sucrose gradients, were digested with RNase T1, and the resulting oligonucleotide-protein complexes were fractionated on SDS containing polyacrylamide gels. Eluted complexes containing 30S proteins S9 and S12 linked to oligonucleotides were obtained in pure form. Oligonucleotide 5'terminal labelling was successful in the case of S12 containing but not of the S9 containing complex and led to identification of the S12 bound oligonucleotide as CAACUCG which is located at positions 1316-1322 in the 16S rRNA sequence. Protein S12 is crosslinked to the terminal G of this heptanucleotide.     

The interaction of N alpha-alkylenkephalins with opiate receptors. Tissue-dependent shifts in the opiate activity of methionine-enkephalin following N alpha-alkylation

Experimental conditions for the small scale alkylation of the alpha-amino group of the opioid peptide methionine-enkephalin using the method of reductive alkylation are described. The generality of the method is established by describing in detail the synthesis, purification, and structure elucidation of the N alpha-ethyl, isopropyl, phenethyl, and cyclopropylmethyl derivatives of methionine-enkephalin. By a combination of amino acid and mass spectral analysis it is possible to carry out the structure analysis of nanomole quantities of these modified peptides, making direct chemical modification and structure elucidation of carrier-free tritiated and radioiodinated enkephalins feasible. Using these chemical procedures, a homologous series of N alpha-n-alkyl derivatives of methionine-enkephalin has has been synthesized. It is shown that the relative binding and opiate activity of these N alpha-alkyl derivatives, using several standard in vitro assay systems, depends on the tissue source used. The results of this study are analyzed by considering recent reports indicating the existence of multiple opiate receptors.     

Chou-Fasman analysis of the secondary structure of F and Le interferons

The Chou-Fasman method for calculating the secondary structure of $\text{F}$ and $\text{Le}$ interferons from their amino acid sequences predicts several regions of homologous structure in the two interferons. Those areas tend to be located in the middle and C- terminal ends of the molecules. Total predicted content of α helix is 55% for $\text{Le}$ interferon and 36% for $\text{F}$ interferon. Predicted β-pleated sheet residues total 33% for $\text{F}$ and 16% for $\text{Le}$.     

AQUATIC MATING STRATEGIES OF THE MALE PACIFIC HARBOR SEAL (PHOCA VITULINA RICHARDII): ARE MALES DEFENDING THE HOTSPOT?

Compared to the harem and resource defense systems of terrestrial mating pinnipeds, males of aquatic mating species appear unable to monopolize females or resources. We investigated movements, acoustics, and aquatic territorial behavior of male harbor seals, Phoca vitulina richardii , in Elkhorn Slough, California, using VHF telemetry, hydrophones, and acoustic playback experiments. During the mating season 22 males increased time spent in the water and away from haul-out locations, exhibiting activity patterns similar to Atlantic subspecies. Two acoustic display patterns were observed. At one location multiple males aggregated to display with acoustic activity peaking one month before peak estrus. At two other locations, lone males displayed primarily during peak estrus. Acoustic display areas were non-adjacent with a mean ± SE size of 4,228 ± 576 m², similar to harbor seal display patterns in the Moray Firth, Scotland. Underwater playbacks of male vocalizations were used to define territorial boundaries by inducing responses from territory-holding males. Four solitary males defended adjacent territories (mean area 39,571 ± 18,818 m²) along a travel corridor, similar to observations of harbor seals at Miquelon, Newfoundland. Acoustic display stations appeared to be subcomponents of larger territories. Males exhibited site fidelity to territories for at least 2–4 yr. Females moved through territories freely. The establishment of male-display territories along female-traffic corridors resembles terrestrial systems described as hotspot leks.