Changes in ecdysone titre during pupal-adult development in the silkworm, Bombyx mori

Changes in the ecdysone titre of the silkworm, Bombyx mori, during pupal-adult development were estimated. The average value of the maximum titre, which was observed on the second day after pupal ecdysis, was about 0·8 μg equivalent of β-ecdysone/g of live weight in both sexes.

There is a distinct sexual dimorphism in the pattern of the ecdysone titre. The male exhibited a single sharp peak on the second day whereas the female showed the second peak on the fifth day. When the female was ovariectomized, the ‘female type’ ecdysone pattern was converted to the ‘male type’. In the female pharate adult 7 days after pupal ecdysis, ecdysone activity accumulated in the ovaries.

The relationship between the ecdysone titre and adult differentiation, especially during ovarian development, is discussed.     

Thermodynamic properties of the photochemical reaction center of Heliobacterium chlorum

The thermodynamic and spectral properties of the photochemical reaction center components of Heliobacterium chlorum have been examined. The primary electron donor bacteriochlorophyll has E_m,7 = +225 mV, and the ‘primary acceptor’ E_m,10 = −510 mV. The former has an EPR signal in its oxidised form near G = 2.0025, ΔH = 0.95 mT, reminiscent of the properties of the primary donor in bacteria containing bacteriochlorophyll a. The ‘primary acceptor’ has properties similar to those of the iron-sulfur cluster acceptors of green sulfur bacteria. H. chlorum contains a c-type cytochrome (E_m,7 = +170 mV) that donates electrons to the photooxidised primary donor with . The reaction center of H. chlorum is thus very similar to that found in representative green sulfur bacteria, but the cellular architecture and photopigments of this group are quite distinct from those of H. chlorum.     

The structure of the wall plate in chthamalus depressus (poli)

The structure of the calcitic shell of extreme hypobiotic Chthamalus depressus (Poli) using untreated, treated, and polished material has been investigated by scanning electron microscopy, and supplemented by observations on normal forms and C. Stellatus (Poli). The laterale has been largely used. The plate is made up of prisms consisting of stacks of units ≈ 5 μm high; the prisms are separated by matrix and intraprismatic organic matter may also be present. The inner side of the plate is penetrated by holes. The structure of the wall plate is reflected in that of the sheath. Epicuticular lamina run across the wall plates separating the stacks of prisms. Attention is drawn to the possible implications with respect to the recent controversy regarding the form of chitin in crustacean endocuticle.

The various structures give the surface a ‘banded’ appearance. From the available data on growth rate, shape, and moulting frequency, estimates are made of the expected size of these bands; the results agree reasonably well with the observations.

The frequency of the smaller bands would seem to be endogenously determined by processes taking place within an intermoult period.     

Cloning, expression, purification and serodiagnostic evaluation of fourteen Mycobacterium paratuberculosis proteins

Fourteen proteins of potential diagnostic value for bovine paratuberculosis were identified in the culture filtrate of Mycobacterium paratuberculosis JTC303 by immunoblot and mass spectrometry. The goals of the present study were to express these 14 ORFs in Escherichia coli and evaluate their antigenicity. All 14 proteins were expressed in E. coli BL21(DE3) after transformation with the pET-22b(+) vector. Yields of insoluble proteins were higher than those of the soluble proteins. Polyclonal rabbit antibodies directed against culture filtrate of JTC303 strain confirmed that five of the expressed and purified proteins are culture filtrate components: ModD, Antigen 85C, PepA, MAP1693c, and MAP2168c. Evaluation of ModD as an ELISA solid-phase antigen on a set of bovine sera from well-characterized paratuberculosis cases and infection-free controls revealed that there was strong serum antibody reactivity to rModD in many infected cattle. However, the overall rModD ELISA sensitivity and specificity for bovine paratuberculosis was not greater than those of ELISAs using crude antigens such as cellular extract or culture filtrate for plate coating, as judged by area under the curve (AUC) of Receiver-operating curve (ROC) analysis. However, an ELISA using natural ModD as the solid-phase antigen had a higher sensitivity and AUC than did rModD suggesting diminution of antigenicity in rModD. Taken together, our results showed that the natural forms of the identified proteins may be useful for diagnosis of bovine paratuberculosis.     

Cosynthesis of monofluoroacetate and 4-fluorothreonine by resting cells of blocked mutants of Streptomyces cattleya NRRL8057

Streptomyces cattleya NRRL 8057 produces monofluoroacetate and 4-fluorothreonine from inorganic fluoride. Mutants blocked in fluorometabolite production were prepared by chemical mutagenesis, and cosynthesis experiments with these blocked mutants were carried out by suspending cells of one blocked mutant in the supernatant broth of another blocked mutant. The harvest age of the cells, pH of the buffer, potassium fluoride concentration and glycerol supplementation were optimized for the monofluoroacetate production by a resting-cell suspension of S. cattleya. Successful cosynthesis with pairs of the mutants characterized four distinctive blocked sites in the order N-82, N-44, N-43 and N-47. Additional preparation of blocked mutants by UV irradiation and their cosynthesis assay confirmed that U-303, U-304, U-400 and U-500 were blocked in later steps than N-47. O’Hagan et al. recently proposed that fluoroacetaldehyde, the hypothetical precursor of monofluoroacetate and 4-fluorothreonine, derives from 5′-fluoro-5′-deoxyadenosine, the first fluorinated metabolite synthesized from S-adenosyl- -methionine and inorganic fluoride by the novel enzyme ‘fluorinase’. We were able to detect fluorinase activity in crude extracts of wild type and N-47 mutant strains, but not in the other mutant strains whose blocked steps flanked that of N-47.     

Phenotypic features of trehalase mutants in Saccharomyces cerevisiae

In the yeast Saccharomyces cerevisiae, some studies have shown that trehalose and its hydrolysis may play an important physiological role during the life cycle of the cell. Recently, other studies demonstrated a close correlation between trehalose levels and tolerance to heat stress, suggesting that trehalose may be a protectant which contributes to thermotolerance. We had reported lack of correlation between trehalose accumulation and increase in thermotolerance under certain conditions, suggesting that trehalose may not mediate thermotolerance [Nwaka, S., et al. (1994) FEBS Lett. 344, 225–228]. Using mutants of the trehalase genes, NTH1 and YBR0106, we have demonstrated the necessity of these genes in recovery of yeast cells after heat shock, suggesting a role of these genes in thermotolerance (Nwaka, S., Kopp, M., and Holzer, H., submitted for publication). In the present paper, we have analysed the expression of the trehalase genes under heat stress conditions and present genetic evidence for the ‘poor-heat-shock-recovery’ phenotype associated with NTH1 and YBR0106 mutants. Furthermore, we show a growth defect of neutral and acid trehalase-deficient mutants during transition from glucose to glycerol, which is probably related to the ‘poor-heat-shock-recovery’ phenomenon.     

Fatty acid composition in microspore-derived secondary embryos of Brassica napus L.

Fatty acid (FA) composition was determined in secondary embryos (SeEs) of Brassica napus L. of the cv. ‘Topas’ and ‘Janetzki’, and compared with the FA composition in microspore-derived embryos (MDEs) and seeds. SeEs of ‘Topas’, a rapessed cultivar with low erucic acid, revealed the same FA composition as observed in the MDEs. The FA pattern was, in most of the cases, independent of the procedures used for induction of SeEs e.g. low density cultures, transversal wounding, auxin treatment, and light conditions. However, non-embryogenic calli, as well as leaves from greenhouse- and in vitro-grown material had a FA composition distinctly different from the MDEs or SeEs. SeEs with an abnormal phenotype revealed differences in FA composition compared to MDEs or SeEs, but was distinct from the composition of non-embryogenic tissues. Virtually no erucic acid (22:1) or eicosaenoic acid (20:1) could be detected in SeEs of ‘Topas’. However, its presence in SeEs of ‘Janetzki’, a high erucic acid rapeseed cultivar, demonstrates that SeEs contain embryo-specific FAs. Under standard culture conditions, the levels of 22:1 and 20:1 were the same as observed in MDEs, which was approximately half the content observed in the seeds. The similarity in FA composition between SeEs and MDEs, of both low and high erucic acid rapeseed cultivars, is a unique characteristic which differs from most other somatic embryogenic systems.     

Defensive Secretions of New Zealand Tenebrionids—The genus Menimus

Prothoracic and abdominal defensive glands are present in the genus Menimus (Coleoptera; Tenebrionidae). The prothoracic glands are small and open laterally into the membrane between the prothorax and the head. The reservoirs of the abdominal glands exceed the length of the abdomen and the secretory tubules end separately in ‘basal lines’ dorsally on the base of each reservoir. Chemical analysis of the glandular secretions revealed the presence of alkylated benzoquinones, ethylphenol and undecene. The relationships of the genus Menimus are discussed.     

A comparison of the tryptic peptides of hemoglobin from two cricetine genera: Peromyscus and Calomys

The composition of tryptic peptides was determined for the major hemoglobin from two cricetine rodents. Peromyscus maniculatus bairdii and Calomys callosus. Amino acid sequences are proposed from homologous alignment with the respective sequences of white mouse and a microtine ‘stem’ developed from previous studies. These two hemoglobins differed at 11 - and 17 β-positions, showing only one common position beyond the cricetid stems (Hesperomyini, Cricetinae) and only three common positions with the microtinae beyond the muroid or myomorph stem (Cricetidae).     

Use of gas chromatograms of essential leaf oils to compare eight taxa of genus Angophora (Myrtaceae): possible relationships to the genus Eucalyptus

Essential oils were extracted from leaves of eight taxa of the genus Angophora, and then analysed. As expected the individual components of these oils were essentially the same as those found in the Eucalyptus species of our earlier studies (Bignell et al., 1997b. Flavour Fragrance J. 12, 423-432). In addition, as is also the case with the bloodwood eucalypts, only relatively low yields of oil were obtained. In all cases the Cineole component was extremely small, but the oils of six of the eight contained very large concentrations of the sesquiterpene Bicyclogermacrene. A table of the 52 major oil components is included. Principal components analysis (PCA) was performed on the gas chromatograms (GC) of the essential oils and the resulting scores plots compared with the cladistic classification of Thiele and Ladiges (1988). Cladistics 4, 23–42). Because of the close relationship between genus Angophora and Eucalyptus ‘subgenus’ Corymbia, the GC data for the eight Angophora taxa were combined with corresponding data for eleven randomly chosen taxa from ‘subgenus’ Corymbia (Bignell et al., 1996b, Flavour Fragrance J. 11, 339–347; 1997a, Flavour Fragnance J. 12, 277–284) and a PCA performed on the total system.     

Plant regeneration from cell suspension-derived protoplasts of Primula malacoides and Primula obconica

Protoplasts were isolated from cell suspension cultures of Primula malacoides cv. ‘Lovely Tokyo’ and P. obconica cv. ‘Aalsmeer Giant White’. P. obconica protoplasts were embedded in 0.1% (w/v) gellan gum-solidified discs comprising MS medium supplemented with 3 mg/l of 2,4-D or picloram, 0.1 mg/l of zeatin, 0.2 M glucose and 0.2 M mannitol, and surrounded by a liquid medium of the same composition except for the addition of 0.1% (w/v) activated charcoal. The protoplasts formed visible colonies, which were transferred to the regeneration medium containing 30 g/l of sucrose, 0.1 mg/l of picloram and 2 mg/l of zeatin for shoot induction. P. malacoides protoplasts formed visible colonies when cultured in disc culture using 0.1% (w/v) gellan gum-solidified MS medium containing 5 mg/l of 2,4-D, 1 mg/l of NAA, 0.1 mg/l of zeatin and 0.4 M glucose. Small calli were transferred to MS medium supplemented with 5 mg/l of zeatin for shoot regeneration. The shoots of both species readily rooted on plant growth regulator-free 1/2 MS medium and successfully acclimatized to greenhouse conditions. The protoplast-derived plants showed some alterations in morphological characteristics from those of the in-vitro-germinated control plants.     

Transitions between cooperative and non-cooperative responding in the 'Pigeon's Dilemma'

Two pigeons played Iterated Prisoner's Dilemma (IPD) against a simulated opponent pre-programmed to play ‘Tit-For-Tat’ (TFT) and ‘Random’ (RND) strategies. Each pigeon received differential amounts of access to food following choices of either ‘cooperate’ or ‘defect’ on a trial. After 1000 trials against TFT and 500 trials against RND, results indicated that choice allocation was optimal when the birds played against RND but was sub-optimal when the birds played against TFT. In order to determine why the pigeons responded suboptimally against TFT, a trial-by-trial analysis of the data was conducted. The analysis revealed that once a pigeon had received the ‘Sucker's’ payoff (S), it was more likely to defect and receive the ‘Temptation’ payoff (T) than to cooperate and receive the ‘Reward’ (R) payoff. Local reinforcement contingencies appear to determine suboptimal responding against TFT in the iterated Pigeon's Dilemma.     

Oxidase of the white rot fungus Panus tigrinus 8/18

Extracellular oxidase of the white rot fungus Panus tigrinus earlier reported as laccase)contains copper but has no absorption spectrum typical of ‘blue’ oxidases. Thioglycolate and sodium azide inhibit the activity of this enzyme at concentrations 2.5–3 orders lower than those needed for fungal laccases. The oxidase of P. tigrinus oxidizes syringaldazine, coniferyl alcohol, ABTS, syringic acid, diaminobenzidine, guaiacol, catechol and vanillylacetone with different efficiencies. Oxygen consumption and no hydrogen peroxide formation were detected during substrate oxidation by P. tigrinus oxidase. It is proposed that P. tigrinus oxidase is a new ligninolytic enzyme.     

The concentration dependence of the ‘zero-shear’ specific viscosity for a commercial hydroxyethylmethylcellulose (HEMC) in water at several temperatures

This short paper presents preliminary results on the ‘zero-shear’ specific viscosity η_sp0 of a commercial hydroxyethylmethylcellulose (Tylose MH-4000) in water, at the temperatures 10, 25 and 40·5°C, over a wide range of concentrations. At the two higher temperatures, two regions are found in the plot of logC[η]₀ against logη_sp0 with a C^*[η]₀ value of about 2·5. This is consistent with the behaviour of other random-coil polymers. At 10°C however, there is an interesting ‘upward shift’ in this plot in the dilute region. It is suggested that this is related to the different degree of hydration of the oligo(ethyleneoxide) side chains at this temperature.     

Serological diagnostic potential of recombinant outer membrane protein (Omp31) from Brucella melitensis in goat and sheep brucellosis

Outer membrane proteins of Brucella have been classified as group 1 (94 or 88 kDa), group 2 (36–38 kDa), and group 3 (31–34 and 25–27 kDa). Two proteins of 25 and 31 kDa with only 34% of identity are included in group 3 and they are coded for by the omp25 and omp31 genes. Proposed study planned to detect antibodies to Brucella melitensis Omp31 in farm goats having history of B. melitensis induced abortions, in B. melitensis-infected goats and sheep. By enzyme-linked immunosorbent assay (ELISA), using recombinant Omp31 as antigen, of 872 farm goats antibodies to Omp31 were detected in 112 (12.8%) cases. Out of 14 naturally infected goats infected with B. melitensis 12 (85.7%) showed anti Omp31 antibodies. Out of 10 naturally infected sheep with Brucella ovis, antibodies to Omp31 were detected only in 6 (60%) cases and in 18 (81.8%) out of 22 cases infected with B. melitensis. Obtained results were also compared with the rose Bengal plate test (RBPT). In controlled experiments, sensitivity and specificity of recombinant Omp31 (rOmp31) ELISA and RBPT were also evaluated and it was found that former test is 100% specific though RBPT has slightly higher sensitivity. In this study, we found a significant difference between the two groups (B. melitensis and B. ovis infected) in terms of the percentage of positive reactions or signal level by an ELISA. The reactivity of the positive sera against the purified rOmp31 was also tested by Western blotting. Sera from B. melitensis-infected animals showed a strong reactivity in comparison to sera from B. ovis-infected animals. The potential diagnostic usefulness of this antigen in combination with other recombinant proteins from B. melitensis would be of great importance in future in eradication of brucellosis.     

Contamination effects by a ‘conventional’ and a ‘biodegradable’ lubricant oil on infaunal recruitment to Antarctic sediments: A field experiment

To investigate the impacts of synthetic lubricants on Antarctic infaunal communities, a field experiment was setup near Australia's Casey Station, East Antarctica. Two types of synthetic lubricants were tested: an ‘Unused’ and ‘Used’ conventional synthetic lubricant, and an alternative marketed as ‘biodegradable’. Clean defaunated sediment was contaminated with the lubricants, decanted into trays, and deployed by divers onto the seabed in a randomised block design. Sediments were sampled 5 and 56 weeks after deployment. After 5 weeks, benthic assemblages that had recruited to the lubricant contaminated sediments were significantly different to those in ‘Control’ sediments, and differences were more pronounced after 56 weeks. Total number of individuals did not significantly differ between treatments after 5 weeks. However, after 56 weeks total individuals in the ‘Control’ sediments were significantly greater than in the contaminated sediments. Nototanais antarcticus (tanaid) and to a lesser extent Monoculodes sp. (gammarid), Tanaid sp. IV and Eudorella sp. (cumacean) had significantly higher abundances in the control sediments after 56 weeks compared to the contaminated sediments. Copepods numerically dominated the benthic assemblages at both sampling times; however, their abundance did not significantly differ across treatments. The community recruiting to the contaminated sediments remained different from that in the ‘Control’ sediments for the duration of the experiment (1 year). The ‘biodegradable’ lubricant was just as environmentally harmful to the Antarctic infauna as the ‘conventional’ lubricant currently used at Australia's Antarctic stations. Our results demonstrate that changes to recruitment are one of the potential environmental consequences of a lubricant spill to Antarctic benthic communities, and reinforce the importance of preventative oil spill management and effective clean-up procedures. Further monitoring of this field experiment will provide much needed information about the long-term impacts by synthetic lubricants in the Antarctic marine environment.     

Some Aspects of Spermiogenesis and Spermatozoan Ultrastructure in Echiniscoides sigismundi (Heterotardigrada: Echiniscoididae)

Some stages of spermiogenesis of the marine heterotardigrade Echiniscoides sigismundi were investigated employing conventional electron microscopy. Spermatids are connected to each other by cytoplasmic bridges. A large vesicle originating from dictyosomes is formed in early spermatids; it becomes condensed in later stages (‘dense body’). Early spermatids contain two mitochondria closely attached and largely unmodified. In an advanced stage of development a (pseudo?) acrosome is formed close to the nucleus. Formation takes place at the face of the nucleus opposite the dictyosomes that had contributed to the dense body. Numerous microtubules lie near the centriole and throughout the cytoplasm. In late spermatids mitochondria located in a membrane-bounded sac lying more or less parallel to the flagellum. These ‘free mitochondria’ as well as the elongated nucleus with the (pseudo?) acrosome give the spermatozoon two additional ‘tails’. Data on spermiogenesis and spermatozoon ultrastructure mainly in marine Heterotardigrada are still very limited and often too anecdotal to allow reasonable conclusions to be drawn. However, structural features shared by Eu- and Heterotardigrada are emphasised.     

Phylogenetic analysis of genera of ‘Akanthophoreinae’ (Crustacea: Tanaidacea)

Phylogenetic relations among tanaidacean genera within ‘Akanthophoreinae’ are addressed using computer-assisted parsimony methods. The morphology-based analysis includes 10 well-defined and described genera: Araphura, Chauliopleona, Collettea, Paragathotanais, Metagathotanais, Paraleptognathia, Paranarthrura, Portaratrum, and Tanaella in Tanaidomorpha, and Glabroapseudes in Apseudomorpha as the outgroup. Chauliopleona and Paraleptognathia form a monophylum; Portaratrum cannot be placed in any known family. These three genera are considered as incertae sedis. The analysis does not support the monophyly of ‘Akanthophoreinae’, and further questions the monophyly of Tanaellidae.     

The effect of constant and changing temperatures on the thermal resistance of Lymnaea peregra (Müller)

The effect of constant and changing temperatures on both high and low lethal temperatures of Lymnaea peregra and the time course of acclimation were investigated. Snails acclimated to 6.5°, 11.5° and 16.5°C showed paradoxical ‘adaptation’ of their high letal temperature and reasonable ‘adaptation’ of the lowlethal temperature. This combination is thus observed for the first time in molluscs. Seasonal variation in the upper lethal temperature showed parallel changes and the snails became less resistant to heat during spring and summer. Acclimation to changing temperature conditions did not extend their temperature tolerance range. During the course of acclimation of 6.5°C snails to 16.5°C, about 70% of the acclimation was completed within the first 24 h and the rest was completed within 360 h at 16.5°C.