Polarization microscopic evidence for an oriented cytoplasmic structure in the ‘dark’ variants of adrenalin-storing cells

Summary A diffuse cytoplasmic birefringence confined to dark adrenalinstoring cells has been described. The main optical characteristics of the birefringence factor include: regular orientation of birefringence relative to the base-apex axis of cells; additive anisotropic staining with methods based on the principle of topo-optical staining reactions; dependence of birefringence on labile morphologic properties. On the basis of the capacity of the macromolecular matrix of chromaffin granules to form lamellar liposomal structures in vitro it has been proposed that a reorientation of molecular organization in the matrix of chromaffin cells is responsible for the observed optical phenomenon. The direction of birefringence was explained by a preferential direction of contractile forces acting during dark cell formation.     

Analysis of the meiosis in the F_1 hybrids of Longiflorum × Asiatic(LA) of lilies(Lilium) using genomic in situ hybridization

Longiflorum and Asiatic lilies of the genus Lilium of the family Liliaceae are two important groups of modern lily cultivars.One of the main trends of lily breeding is to realize introgression between these groups.With cut style pollination and embryo rescue,distant hybrids between the two groups have been obtained.However,the F1 hybrids are highly sterile or some of them could produce a small number of 2n gametes,and their BC1 progenies are usually triploids.Dutch lily breeders have selected many cultivars...     

Does the unusual life history of the precocial cavy (Cavia magna) translate into an exceptional field metabolic rate?

An association between metabolic rate and life history has been predicted but not demonstrated yet. To test this prediction, we measured the field metabolic rate (FMR) of a rodent, Cavia magna, which has an unusual combination of life-history traits. Cavies live aboveground, feed on energy-poor diets, and take relatively long to produce a few highly precocial young. This "slow-living" life history might predict a relatively low metabolic rate. We recorded FMR of 29 individuals of C. magna in Uruguay using doubly labeled water. This represents the first FMR record for a hystricomorph rodent. Besides body mass, season best explained variation in recorded FMR, with higher daily energy expenditures during winter. Surprisingly, the reproductive state of females did not affect FMR. Comparison with allometric prediction did not support the hypothesis that the slow-living life history of precocial grazing cavies translates into relatively low FMR. However, the clear effect of season on FMR as well as the fact that cavies appear able to compensate for the energy cost of reproduction might be associated with the nonburrowing precocial life history of this species.     

An investigation of the inclusion complex of cyclomaltoheptaose (β-cyclodextrin) with N-methylanthranilic acid in the solid state

A 2:1 complex between cyclomaltoheptaose (β-cyclodextrin) and N-methylanthranilic acid has been studied in the solid state. The inclusion complex belongs to the triclinic system (space group P1) with unit cell dimensions a = 15.2773(15) Å, b = 15.4710(15) Å, c = 17.9627(18) Å, α = 99.632(5)°, β = 113.416(5)°, and γ = 102.818(5)°. The complex forms a head-to-head channel-type structure with the N-methylanthranilic acid lying between the β-cyclodextrin groups in a sandwich fashion, which is held in place by an extensive hydrogen-bonding network between the cyclodextrin molecules.     

The microscopic anatomy and ultrastructure of the contractile vessel in the sipunculan Themiste hexadactyla (Satô, 1930) (Sipuncula: Sipunculidea)

The microscopic anatomy and ultrastructure of the contractile vessel of the sipunculan Themiste hexadactyla (Satô, 1930) from Vostok Bay (the Sea of Japan) were studied by histological and electron microscope methods. The ultrastructural features of the internal (endothelium) and external (coelothelium) lining of the contractile vessel are described and illustrated. Numerous macromolecular filters, the so-called “double diaphragms,” were found in the external coelothelium facing the cavity of the trunk coelom. This suggests a possible filtration from the tentacular coelom into the trunk coelom though the contractile vessel wall. The microscopic peculiarities of the main tube of the contractile vessel and its numerous lateral branches twining around several internal organs are described in detail. The contractile vessel is polyfunctional: it can act as the main reservoir for the cavity fluid during the withdrawal of the tentacular crown and performs the functions of the distribution system in sipunculans.     

Cytochrome oxidase activity associated with the inside of the cytoplasmic membrane in swarm cells and sheath-forming cells of Sphaerotilus natans: an ultrastructural study using 3,3′-diaminobenzidine (DAB)

Cytochrome oxidase activity has been demonstrated by electronmicroscopical cytochemical methods in swarm cells as well as in the sheathforming cells of Sphaerotilus natans. This enzyme is associated with the inside of the cytoplasmic membrane. The conditions for demonstrating this cytoplasmic membrane-associated cytochrome oxidase differ from those enabling the demonstration of the cytochrome oxidase in the polar organelle of this bacterial species. The location of this enzyme also contrasted to that generally known from other bacteria and from mitochondria.     

Complementation of aChlamydomonas reinhardtii mutant defective in the nuclear gene encoding the chloroplast coupling factor 1 (CF1) γ-subunit (atpC)

Chlamydomonas reinhardtii strainatpC1 is a mutant defective in the nuclear gene that encodes the CF₁ ATP synthase -subunit polypeptide. Photoautotrophic growth was restored toatpC1 after it was transformed with wild-type DNA. Transformed strains were acetate-independent and arsenate-sensitive, similar in phenotype to the progenitor wild-type strain from whichatpC1 was generated. Three transformed strains were examined in detail. Southern blot analyses demonstrated that the transformants were complements and not revertants. The transforming DNA integrated into the nuclear genome in a nonhomologous manner and at a low copy number. Northern blot analyses showed that the -subunit mRNA in the complemented strains was expressed at the same relative level as that of wild-type. Western blots of total protein showed that whereasatpC1 was unable to synthesize any CF₁ -subunit, all three complemented strains could. Furthermore, the Western blot analyses demonstrated that the mutation inatpC1 had a pleiotropic effect on the accumulation of the CF₁ -subunit which was relieved upon complementation. Cell extracts fromatpC1 did not have any CF₁-dependent catalytic activity, whereas extracts from all of the complemented strains and the wild-type strain had identical activities.The nucleotide sequence reported in this paper is in the GenBank data bank with accession number M73493.     

Binding of the Human “Electron Transferring Flavoprotein” (ETF) to the Medium Chain Acyl-CoA Dehydrogenase (MCAD) Involves an Arginine and Histidine Residue

The interaction between the “electron transferring flavoprotein” (ETF) and medium chain acyl-CoA dehydrogenase (MCAD) enables successful flavin to flavin electron transfer, crucial for the β-oxidation of fatty acids. The exact biochemical determinants for ETF binding to MCAD are unknown. Here we show that binding of human ETF, to MCAD, was inhibited by 2,3-butanedione and diethylpyrocarbonate (DEPC) and reversed by incubation with free arginine and hydroxylamine respectively. Spectral analyses of native ETF vs modified ETF suggested that flavin binding was not affected and that the loss of ETF activity with MCAD involved modification of one ETF arginine residue and one ETF histidine residue respectively. MCAD and octanoyl-CoA protected ETF against inactivation by both 2,3-butanedione and DEPC indicating that the arginine and histidine residues are present in or around the MCAD binding site. Comparison of exposed arginine and histidine residues among different ETF species, however, indicates that arginine residues are highly conserved but that histidine residues are not. These results lead us to conclude that this single arginine residue is essential for the binding of ETF to MCAD, but that the single histidine residue, although involved, is not.     

Identification and characterization of genes abnormally expressed in wing-deficient mutant (flügellos) of the silkworm,Bombyx mori

The wing-deficient mutant, flügellos (fl), of the silkworm lacks four wings in the pupa and the adult, due to aberrant wing morphogenesis during metamorphosis. To elucidate the mechanisms of wing-specific deficiencies in the fl mutant, we used mRNA differential display and identified five genes abnormally expressed in the fl wing discs. Northern blot and RT-PCR analyses revealed that four genes were overexpressed, but the fifth one was not transcribed in the fl wing discs. The expression level of ribosome-associated protein p40 in the fl wing discs was elevated approximately 10 times compared to the wild-type (WT) discs. Another overexpressed gene CB10 encodes a novel wing-specific protein with a putative zinc-finger motif. Overexpression of two components of extracellular matrix, cuticle protein 18 (BMCP18) and a fibrillin-like protein AD10, may result in the abnormal wing morphogenesis in the fl mutant. In contrast, a novel member of multifunctional Ca2+-binding protein annexins, designated as annexin b13 (Anx b13), was expressed dominantly in the wing discs of WT but completely repressed in the fl tissues. Strong expression of Anx b13 in wing discs during the fourth and fifth instar indicates that ANX B13 plays an important role in wing morphogenesis.     

Removal of α-naphthol and other phenolic compounds from polluted water by white radish (Raphanus sativus) peroxidase in the presence of an additive, polyethylene glycol

Role of white radish peroxidase has been investigated in the treatment of water contaminated with phenols, particularly α-naphthol. Water polluted with α-naphthol was treated with white radish peroxidase under various experimental conditions. The treatment of α-naphthol polluted water by this enzyme in presence of polyethylene glycol enhanced its removal. Studies carried out in absence of polyethylene glycol showed only 36% of α-naphthol removal however, 96% of it was removed in presence of 0.1 mg/mL of polyethylene glycol in 100 mM sodium phosphate buffer, pH 6.5, and 0.75 mM H₂O₂ at 40°C. The other phenols oxidized and removed from waste water under similar experimental conditions were 18%, m-cresol; 30%, p-chlorophenol; 62%, p-bromophenol; 20%, benzyl alcohol; 21%, quinol; 38%, 2,6-dichlorophenol; 13%, 2,4-dichlorophenol; and 2%, native phenol. Mixtures of different phenolic compounds removed under identical treatment conditions were 63%, A; 40%, B; 52%, C; 41%, D; 72%, E; 66%, F; and 72%, G. Thus, peroxidase in presence of an additive, polyethylene glycol could be a suitable tool for the removal of phenolic compounds from industrial effluents.     

Genetic regulation of the class conversion of dsDNA-specific antibodies in (NZB × NZW)F1 hybrid

To investigate the possible effects of NZW genes on the class conversion of dsDNA-specific antibodies in NZB X NZW (B/W)F1 hybrids, we measured IgM, IgG1, and IgG2 dsDNA-specific antibodies, using the Crithidia luciliae kinetoplast immunofluorescence test, in NZB, NZW, B/W F1 hybrid, B/W F1 X NZB backcross, and B/W F1 X NZW backcross mice at 4, 7, and 10 months of age. The highest serum levels of IgM dsDNA-specific antibodies were observed in NZB mice at the ages tested; however, the amounts of IgG1 and IgG2 antibodies were scanty. In contrast, a large amount of both IgG1 and IgG2 dsDNA-specific antibodies was produced in B/W F1 hybrids, in which the serum IgM antibodies were lower than those observed in NZB mice. NZW mice were virtually negative for these antibodies. Progeny testing suggested that a combined effect of two unlinked dominant genes of the NZB strain determines the production of dsDNA-specific antibodies and that these genes only act to produce IgM antibodies. These traits are to a great degree modified by the NZW loci in B/W F1 hybrids, and a combined effect of two unlinked dominant genes leads to conversion of the class of the antibodies from IgM to IgG, which, in turn, increases the serum levels of dsDNA-specific antibodies. The F1 hybrid of C57BL/6 and NZW strains produced no dsDNA-specific antibodies, indicating that the relevant NZB predisposing genes are required for the NZW gene action. Linkage studies showed that one of such NZW genes is to some extent linked to the H-2 complex on chromosome 17, but not to Mup-1 (chromosome 4) or a coat color locus (chromosome 2). The appearance of IgG dsDNA-specific antibodies correlated well with the incidence of renal disease in B/W F1 X NZB backcross mice.     

Selection of Fruit by Gibbons (Hylobates muelleri × agilis) in the Rain Forests of Central Borneo

Gibbons (Hylobates spp.) are among the main frugivorous primates in Southeast Asia, yet little is known about the criteria by which they select fruit for consumption. We studied two gibbon groups for 14 mo in the lowland dipterocarp forests of Central Borneo to determine their selectivity for different fruit species and traits. Ideal gibbon fruit were yellow, large, with a juicy-soft pulp, thin skin and available in large crops. Gibbons ultimately sought seedless fruit, but when seeds were present they selected fruit with a single, well-protected seed. Given that few fruit exhibited all the desired traits, we also carried out a multiple regression using the selection ratios of the various fruit species and their associated fruit traits to determine which traits ultimately determined gibbon choice. The analysis was stratified to account for differences in fruit availability. Selection was strongest when fruit were abundant in the forest and was based on seed width (<21 mm), color (yellow-orange), and fruit weight (1–5 g). No selection is apparent when food abundance was intermediate, but when fruit were scarce they preferentially ate larger fruit (6–30 g).     

Is an ovulation-inducing factor (OIF) present in the seminal plasma of rabbits?

The objectives of this study were (1) to determine the effect of rabbit seminal plasma on LH secretion and ovulation using the llama animal model as an in vivo ovulation bioassay and (2) to determine the effect of llama or rabbit seminal plasma on ovulation induction in the rabbit model. In Experiment 1, llamas with a growing follicle ≥8mm in diameter were assigned randomly to one of three groups (n=5 per group) and given an intramuscular dose of 1mL of: (a) llama seminal plasma, (b) rabbit seminal plasma, or (c) phosphate buffered saline (PBS; negative control). Blood samples for LH measurement were taken every 15 min from 1.5 h before to 8 h after treatment (Day 0: starting of treatment). Llamas were examined by ultrasonography every 12h from treatment to ovulation, and then every other day until Day 16 after treatment to evaluate corpus luteum (CL) development. Blood samples for progesterone measurement were taken every other day from Day 0 to Day 16. Ovulation was detected in 4 of 5, 5 of 5, and 0 of 0 llamas treated with llama or rabbit seminal plasma and PBS, respectively (P<0.001). After treatment, plasma LH concentration increased and decreased (P<0.01) in the llama and rabbit seminal plasma group but not in the PBS-treated group. No differences were observed on CL development (P≥0.3) and progesterone secretion (P>0.05) between both seminal plasma treated groups. In Experiment 2, receptive female rabbits (n=5-7 per group) were given an intramuscular dose of: (a) 0.5, (b) 1.0 and (c) 2.0mL of either rabbit or llama seminal plasma, (d) 0.5mL PBS (negative control), or (e) 25μg of gonadoreline acetate (GnRH; positive control). Does were submitted to laparotomy 24-36 h after treatment to determine the ovulatory response and the presence of antral and hemorrhagic anovulatory follicles. Ovulation sites (7.0±0.6) were only detected in GnRH-treated does (P<0.01). There was an increase (P<0.01), in the total number of follicles (antral plus hemorraghic follicles) in those females treated with 1mL of rabbit seminal plasma and there was a tendency (P=0.08) for more hemorrhagic anovulatory follicles in does treated with 1.0 and 2.0mL of either rabbit or llama seminal plasma. Results document the presence of OIF in the seminal plasma of rabbits. The differential ovulatory response between species, however, requires further investigation.     

A plant MinD homologue rescues Escherichia coli HL1 mutant (ΔMinDE) in the absence of MinE

Background  

In E. coli, the Min operon (MinCDE) plays a key role in determining the site of cell division. MinE oscillates from the middle to one pole or another to drive the MinCD complex to the end of the cell. The MinCD complex prevents FtsZ ring formation and the subsequent cell division at cell ends. In Arabidopsis thaliana, a homologue of MinD has been shown to be involved in the positioning of chloroplast division site.     

Study of the inclusion of the (R)- and (S)-camphor enantiomers in α-cyclodextrin by X-ray crystallography and molecular dynamics

The inclusion of (R)- and (S)-camphor compounds in α-cyclodextrin has been studied by X-ray crystallography. The crystal structures of the complexes reveal that one guest molecule is accommodated inside the cavity formed by a head-to-head cyclodextrin dimer. In the crystal lattice, the dimers form layers which are successively shifted by half a dimer. In both (R)- and (S)-cases, the camphor molecule exhibits disorder and occupies three major sites with orientations that can be described as either ‘polar’ or ‘equatorial’. Molecular dynamics simulations performed for the observed complexes indicate that although the carbonyl oxygen of both (R)- and (S)-camphor switches between different hydrogen bonding partners, it maintains the observed mode of ‘polar’ or ‘equatorial’ alignment.     

Effect of temperature on locomotor activity in the goldfish (Carassius auratus) and the bluegill (Lepomis macrochirus): Presence of an ‘activity well’ in the region of the final preferendum

Goldfish (Carassius auratus) and bluegill sunfish (Lepomis macrochirus) were placed in aquaria where their locomotor activity was monitored by photocells, and tested at various acclimation temperatures over a range encompassing their final thermal preferenda. Activity was pooled over 24-hour periods to eliminate any circadian rhythm effects. Both species exhibited an activity well of reduced locomotor activity in the region of the final preferendum. Goldfish, tested either singly or in groups of 2–5 individuals, exhibited a social-interaction effect which became more pronounced at higher temperatures. These results are discussed in relation to a thermokinetic interpretation of thermo-regulatory behavior in fishes, and to the correspondence between thermal preferenda and thermal optima.