Glutathione-proline activation of feeding behavior in the zoanthid Palythoa psammophilia Walsh & Bowers

Palythoa psammophilia Walsh & Bowers has a well coordinated, stereotyped feeding response, the culminating step of which is ingestion; this may be elicited by the synergistic effect of the tripeptide glutathione and the -imino acid, proline. Either activator acting separately causes responses only at high concentrations (above 10⁻⁵ M for glutathione; above 10⁻⁴ M for proline) in a reduced number of animals and at a low rate (5.00 ± 1.73 min in 5 × 10⁻³ M solutions of glutathione; 11.10±3.74 min in 5 × 10⁻³ M solutions of proline). Highest percentages of response were obtained in combinations where glutathione was at a concentration of 5 × 10⁻³ M and proline at 5 × 10⁻⁴ M or in combinations of glutathione at concentrations 5 × 10⁻⁶ M and proline at 5 × 10⁻⁵ M. The speed of ingestion is considerably enhanced when these activators are combined (1.17±1.18 min).     

Inhibition of nucleolar reformation after microinjection of antibodies to RNA polymerase I into mitotic cells

The formation of daughter nuclei and the reformation of nucleolar structures was studied after microinjection of antibodies to RNA polymerase I into dividing cultured cells (PtK2). The fate of several nucleolar proteins representing the three main structural subcomponents of the nucleolus was examined by immunofluorescence and electron microscopy. The results show that the RNA polymerase I antibodies do not interfere with normal mitotic progression or the early steps of nucleologenesis, i.e., the aggregation of nucleolar material into prenucleolar bodies. However, they inhibit the telophasic coalescence of the prenucleolar bodies into the chromosomal nucleolar organizer regions, thus preventing the formation of new nucleoli. These prenucleolar bodies show a fibrillar organization that also compositionally resembles the dense fibrillar component of interphase nucleoli. We conclude that during normal nucleologenesis the dense fibrillar component forms from preformed entities around nucleolar organizer regions, and that this association seems to be dependent on the presence of an active form of RNA polymerase I.     

The relationship between the digestive enzymes in arctic char,Salvelinus alpinus (Salmonidae,Osteichthyes) and its ability to survive in extreme environments

Digestive enzymes of chars from seven Austrian lakes have been studied. Trypsin activity ml⁻¹ fluid is proportional to body size but inversely proportional to the amount of food in the digestive tract. The pancreas appears to secrete trypsin ± continuously and the activity measureable in the intestinal fluid seems to depend largely on the gut passage rate. There is no seasonal rhythm of enzyme activity. Amylase activity is very weak. Pepsin activity seems to depend mostly on the dilution of the gastric juice. The results indicate that the steering mechanisms of digestive enzymes in salmonidae are well distinct from other families. This work was part of a PH. D. thesis (Reimer, 1984). This work was part of a PH. D. thesis (Reimer, 1984).     

Cyclophosphamide-Induced IN VIVO Sister Chromatid Exchanges (Sce) in MUS MUSCULUS. III. Quantitative Genetic Analysis

In vivo cyclophosphamide (CP)-induced sister chromatid exchanges (SCEs) were evaluated in females from five genetic strains of mice (C57BL/6J, C3H/S, 129/ReJ, BALB/c and DBA/2) and their F₁ hybrids. Baseline (noninduced) SCE values differ significantly among strains, 129/ReJ having the lowest and DBA/2 having the highest mean SCE per cell values. In general, the baseline SCE of a given F₁ is within the range of its corresponding parental strains or near the lower parental value. Furthermore, there is a genotype-dependent increase in mean SCEs per cell with CP dose. Strain differences in SCE induction are noted particularly at the two higher CP doses (4.50 and 45.0 mg/kg). In general, F₁ hybrids involving a strain with high induced SCEs and a strain with low induced SCEs exhibit mean SCE values that are closer to the value of the lower strain. F₁ s involving two strains with high SCEs or two strains with low SCEs yield SCEs not different from parental strains. The method of diallel cross analysis showed the order of dominance of these strains in SCE induction to be 129/ReJ BALB/c C3H/S DBA/2 C57BL/6J. These results support the involvement of predominantly nonadditive genetic factors as major gene(s) in SCE induction. In addition, involvement of random and independent events in SCE induction is suggested by the distribution of SCEs which follows a Poisson distribution.     

Anti-native DNA antibodies from autoimmune sera also bind to DNA in mitochondria

Sera from 20 patients with systemic lupus erythematosus (SLE), selected for elevated titers of antibody to native DNA (nDNA), were examined by indirect immunofluorescence (IF) on tissue culture Hep-2 and rabbit kidney cells. Twelve sera showed a particulate cytoplasmic staining, in addition to nuclear IF. Double IF staining by using a mouse monoclonal anti-nDNA and a human serum containing anti-mitochondrial antibody as probes showed that the cytoplasmic structures recognized by these 12 SLE sera were mitochondria. SLE sera showing mitochondrial staining had high anti-nDNA levels, as assessed by ELISA (3.5 +/- 1.9 O.D.), compared with those not showing this staining pattern (0.8 +/- 0.4 O.D.). Mitochondrial staining was abolished by DNase I pretreatment of the substrates. Liquid phase absorption of serum anti-nDNA with S1 nuclease-treated calf thymus DNA or purified mitochondrial DNA also removed staining. These findings demonstrate that anti-nDNA antibodies from patients with SLE bind to DNA in intact mitochondria. Therefore, mitochondrial IF staining on tissue culture cells in the presence of nuclear staining should be interpreted with caution, because the phenomenon could be entirely related to anti-native DNA. These observations might also provide new insights concerning the nature of immunogenic cellular components stimulating anti-DNA production.     

Arsenic speciation in marine interstitial water. The occurrence of organoarsenicals

Arsenic speciation data are presented for pore waters squeezed from some native and anthropogenically influenced sediments.Ten stations were sampled with a box corer (to 20 cm) at two British Columbia coastal sites that are influenced by mine-tailings discharges. These are Rupert Inlet and Alice Arm as well as their associated systems of Quatsino Sound/Holberg Inlet and Hastings Arm respectively.Total dissolved arsenic concentrations (As _D) usually exhibited subsurface maxima at 5–10 cm and were generally related to solid phase arsenic (As _p) levels, but there was also a dependence on the nature of the substrate. Tailings exhibited both the lowest (Rupert Inlet) and the highest (Alice Arm) As _D values. Inorganic arsenicals, arsenate (AsV) and arsenite (AsIII) constituted the majority (>90%) of the dissolved species butevery sample contained organoarsenicals. This is the first report of mono-, di- and tri-methylated arsenic species in marine interstitial water.A strong positive correlation between the sum of the methylarsenic compounds (MeAs) and the total dissolved arsenic (As _D) was found, indicating in situ microbial methylation similar to that observed in non-aquatic systems. Flux values for arsenic at the sediment-water interface suggest that, at present, there is no significant mobilization of arsenic from these mine-derived sediments into the water column.     

The identification of 5,6-dihydrouridine in normal human urine by combined gas chromatography/mass spectrometry

The identification of 5,6-dihydrouridine in normal human urine is reported. Partial purification and isolation of the compound by boronate gel affinity chromatography and reversed-phase high-performance liquid chromatography preceded its characterization as a trimethylsilyl derivative by combined gas chromatography/mass spectrometry. Structure proof is based upon a comparison of mass spectral and chromatographic features of the urinary component to that of an authentic reference sample. Additional data derived from high resolution mass measurements and deuterium isotope-labeling experiments provide confirmation of fragment ion structure. The poor detectability inherent in the HPLC/uv analysis of nucleosides is also discussed.     

The histochemical specificity of High Iron Diamine—Alcian Blue

Summary The specificity of the High Iron Diamine—Alcian Blue pH2.5 (HID—AB 2.5) procedure was examined in tissue sites containing sialogycoproteins alone or differing proportions of sialo- and sulphosialoglycoproteins. Studies with HID in differing final concentrations of hydrochloric acid or sodium chloride confirmed that staining is dependent upon both the pH and the ionic strength of the dye bath and demonstrated a marked heterogeneity in the pKa of the anionic groups of sialosulphoglycoproteins. Use of the sequence High Iron Diamine—Alcian Blue pH 1.0 demonstrated that complete or almost complete staining ofO-sulphate esters occurred when HID was prepared in water (final pH 1.3). However, under these conditions HID—AB 2.5 was shown to be non-specific because only black HID staining was observed in sites containing large quantities of sialic acids. This non-specificity was due either to the masking of Alcian Blue staining by HID and/or the black HID staining of anionic groups other than sulphate. These results may account for some of the conflicting data obtained by different groups of investigators who have studied transitional mucosa in human colonic diseases. Caution should be used in drawing conclusions from the use of HID—AB 2.5 without confirmatory evidence from other more specific procedures.     

Populations of a widespread hexacoral have trophic plasticity and flexible syntrophic interactions across the Indo-Pacific Ocean

Coral Reefs - Benthic cnidarians are suspension feeders that ingest items ranging from particulate organic matter to macrozooplankton. Additionally, many species receive photosynthetic products...