Effect of growth temperature on complement-mediated killing of mesophilic Aeromonas spp. serotype O:34

Abstract Mesophilic Aeromonas spp. strains (serotype O:34) showed sensitivity to complement-mediated killing when they were cultivated at 37°C (serum-sensitive) but not when they were cultivated at 20°C (serum-resistant). These strains produced smooth lipopolysaccharide when they were grown at 20°C and rough lipolysaccharide when cultivated at 37°C. The reason for the resistance to complement-mediated killing could be that C3b is rapidly degraded (possibly because it is bound far from the cell membrane), consequently the lytic complex (C5b-9) is not formed.     

Inorganic phosphate effect on alternate peripheral pathways of glucose catabolism in Pseudomonas cepacia

Abstract The effect of the inorganic phosphate concentration on the activity of the enzyme of alternate peripheral pathways of glucose catabolism was studied in Pseudomonas cepacia ATCC 17759. Growth with low glucose concentration (0.5% w/v) and 20 mM phosphate resulted in induced levels of the phosphorylative pathway enzymes when compared with the levels of these same enzymes in high glucose concentration (2% w/v). However, an expansion of the oxidative pathway was detected during growth with 0.5% (w/v) of glucose and high phosphate concentration (160 mM). Moreover, under high phosphate (160 mM) and high glucose (2% w/v) growth conditions, glucokinase activity was increased preferentially relative to levels of direct oxidative pathway enzymes.     

Floristic variation,chorological types and diversity: do they correspond at broad and local scales?

Abstract. The relationships between biogeographical patterns and local‐scale patterns based on microscale features, such as topoclimate, are well known in plant biogeography. Here we present a method of determining this correspondence using constrained ordination and correlations. We examined compositional gradients at two different scales, biogeographical chorotypes, and diversity. Compositional data (124 taxa × 113 plots) were sampled at four regularly spaced sites in south‐eastern Spain. Longitude (LONGI) was used as a spatial variable representing an east–west climate gradient, together with a radiation index (RADIN), elevation, and a disturbance indicator. All factors correlated with the compositional gradients, but the local‐topoclimate factor (RADIN) and the broad‐scale factor (LONGI) were most important. These two, spatially independent factors were both correlated with the two first ordination axes, and therefore should relate to the same general trend in species‐turnover. There was a significant Spearman's rank correlation between the species order along these two gradients. This is interpreted as an ecological self‐similar pattern, i.e. coenoclines repeating at different scales. A consistent order of species along local‐ and broad‐scale coenoclines may indicate that similar operational factors act at several scales, here related to moisture and temperature. The distribution of Mediterraneo–Macaronesian, Mediterraneo–Saharo–Arabian and Ibero–Maghribian species confirmed the correspondence between the broad‐ and local‐scale gradients. The former group decreases in number with increasing aridity along both gradients, whereas the two latter groups increase. A discordant pattern was found with south‐eastern Iberian endemics, but this may be explained by several of them being edaphic (saxicolous) specialists. There is a significant decrease in species richness with high radiation, but the expected increase along the longitudinal gradient from west (dry) to east (moist) was not statistically significant. This may be due to the correspondence between high richness and disturbance, both occurring in the middle of the broad‐scale gradient.     

Capsular polysaccharide expressed by Pasteurella piscicida grown in vitro

Abstract Pasteurella piscicida grown in a glucose-rich medium produces a capsule that can be see under light and electron microscopy. The capsular polysaccharide was purified and characterized by chemical and HPLC analysis. The polymer has the composition glucose/mannose/ N -acetylgalactosamine/galacturonic acid/acetic acid in the molar ratios of approximately 2.5:1.3:0.5:0.4:2.5. The polysaccharide was immunogenic in rabbits and did not cross-react with antibodies against the O-antigen lipopolysaccharide.     

Effect of cellobiose supplementation and dietary soluble fibre content on in vitro caecal fermentation of carbohydrate-rich substrates in rabbits

The in vitro caecal fermentation of five substrates low in starch and protein content [d-(+)-glucose (GLU), d-cellobiose (CEL), sugar beet pectin (PEC), sugar beet pulp (SBP) and wheat straw (WS)] was investigated using soft faeces from rabbits receiving different levels of cellobiose and soluble fibre as inoculum. A total of 24 rabbits were supplemented 3 levels of cellobiose in the drinking water (0.0, 7.5, 15.0 g/l) and fed two experimental diets containing either low soluble fibre (LSF) or high soluble fibre (HSF) levels (84.0 and 130 g/kg dry matter). All substrates were subjected to a two-step pepsin/pancreatin in vitro pre-digestion, and the whole residue was used as substrate for the in vitro incubations. Gas production was measured until 144 h, and volatile fatty acid (VFA) production was determined at 24 h incubation. Experimental treatments did not affect SBP fermentation and had only a subtle influence on fermentation of WS and GLU. In contrast, cellobiose supplementation × donors’ diet interactions were detected for most gas production parameters for CEL. Both the fractional gas production (k) and maximal gas production rates were linearly increased (p ≤ 0.042) and the initial delay in the onset of gas production (Lag) linearly decreased (p < 0.001) by cellobiose supplementation with the HSF inoculum, with no differences between the 7.5 and 15.0 doses. In contrast, with the LSF inoculum cellobiose supplementation only affected k values, which were quadratically increased (p = 0.043) and had maximal values for the 7.5 dose. A quadratic effect (p ≤ 0.018) of cellobiose supplementation was observed for total VFA production at 24 h when CEL and PEC were fermented, obtaining the maximal VFA production for the 7.5 dose of cellobiose. Total VFA production for CEL was greater with LSF than with HSF inoculum (20.7 vs. 12.9 mmol/l; p = 0.014), but the opposite was found for WS (3.97 vs. 6.21 mmol/l; p = 0.005). The use of LSF inoculum for CEL fermentation sharply reduced acetate (p = 0.001) and increased butyrate proportions (p ≤ 0.001) compared with the HSF inoculum. A positive relationship between total VFA caecal concentrations in rabbits receiving the same experimental treatments and in vitro values was only observed when WS was used as substrate (r = 0.90; p = 0.015; n = 6). The results suggest that experimental factors influenced the fermentative activity of caecal digesta, but the observed response differed with the incubated substrate, being the CEL the most affected.     

Photobacterium malacitanum sp. nov., and Photobacterium andalusiense sp. nov., two new bacteria isolated from diseased farmed fish in Southern Spain

Three strains, H01100409B^T, H01100413B, and H27100402H^T, were isolated from several internal organs of diseased redbanded seabream (Pagrus auriga) reared in Andalusia (Southern Spain). All strains were studied by phenotypic, including chemotaxonomy, and genomic characteristics. Phylogenetic analysis based on concatenated sequences of six housekeeping genes (gyrB, ftsZ, topA, mreB, gapA, and 16S rRNA) supported the inclusion of the strains within the clade Phosphoreum of the genus Photobacterium, and two of the strains (H27100402H^T and H01100409B^T) formed a tight group separated from the closest species P. aquimaris. Genomic analyses, including average nucleotide identity (ANIb and ANIm) and DNA–DNA hybridization (DDH), clearly separated strains H27100402H^T and H01100409B^T from the other species within the clade Phosphoreum with values below the thresholds for species delineation. The chemotaxonomic features (including FAME analysis and MALDI-TOF-MS) of H27100402H^T and H01100409B^T strains confirmed their differentiation from the related taxa. The results demonstrated that strain H01100413B was classified as P. aquimaris and the strains H27100402H^T and H01100409B^T represented a new species each in the genus Photobacterium, for which we propose the names Photobacterium malacitanum sp. nov., type strain H27100402H^T (=CECT 9190^T = LMG 29992^T), and Photobacterium andalusiense sp. nov., type strain H01100409B^T (=CECT 9192^T = LMG 29994^T).     

Fractionation and characterization of boar seminal plasma spermadhesin PSP-II glycoforms reveal the presence of uncommon N-acetylgalactosamine-containing N-linked oligosaccharides

Lectin mapping, carbohydrate analysis and electrospray mass spectrometry of boar seminal plasma PSP-II glycoforms show that its single N-glycosylation site displays a repertoire of carbohydrate structures consisting of the basic pentasaccharide core Manα 1–6[Manα 1–3]Manβ1-4GlcNAcβ1-4GlcNAc with a fucosyl residue α1-6-linked to the innermost N-acetylglucosamine residue. Other glycoforms display fucosylated hybrid-type or monoantennary complex-type chains, some of which contain α2-6-linked sialic acid. N-acetylgalactosamine, possibly in Galβ1-3GalNAc sequence, is present in most of the PSP-II glycoforms. Abbreviations: PSP-I and PSP-II, porcine seminal plasma proteins I and II; PNGaseF, peptide-N4-(N-acetyl-β-D-glucosaminyl) asparagine amidase (EC 3.5.1.52) from Flavobacterium meningosepticum; ConA, Cannavalia ensiformis (jack bean) agglutinin; GNA, Galanthus nivalis (snowdrop) agglutin; SNA, Sambucus nigra (elderberry) agglutinin; MAA, Maackia amurensis (maakia) agglutinin; PNA, Arachis hypogaea (peanut) agglutinin; DSA, Datura stramonium (jimson weed) agglutinin; AAA, Aleuria aurantia agglutinin This revised version was published online in November 2006 with corrections to the Cover Date.     

The Expression of an Abscisic Acid-Responsive Glycine-Rich Protein Coincides with the Level of Seed Dormancy in Fagus sylvatica

By differential screening of a cDNA library constructed frompoly (A⁺) RNA of ABA-treated seeds of Fagus sylvatica L., wehave isolated an ABA-responsive clone that is present in dormantseeds and under conditions that maintain dormancy, but it tendsto disappear under conditions breaking seed dormancy. A searchof the sequence data bases showed that the clone codes for aGlycine-Rich Protein and has sequence similarity to RNA-bindingproteins. The clone, which exibits the characteristics of lea-genes,is up-regulated by ABA and down-regulated by GA3. Paclobutrazolabolishes the effect of GA³, which is restored upon additionof GA3. The possible relationship of this Glycine-Rich Proteinto seed dormancy in F. sylvatica is discussed. (Received May 23, 1997; Accepted September 22, 1997)     

α-d-galactosidase deficiency in coconut endosperm: its possible pleiotropic effects in makapuno

α-d-galactosidase (α-d-galactoside galactohydrolase, EC 3.2.1.22) activity in the normal endosperm increased with age continually up to endosperm maturity. In contrast, makapuno α-d-galactosidase was hardly detected in almost all stages of development except the last, where its activity was 8300-fold lower as compared to the normal. The possible role of α-d-galactosidase in the formation of the makapuno endosperm is discussed.     

CYTOKINETICS OF THE S-180 ASCITES TUMOR SYSTEM

The cytokinetics of the S-180 mouse ascites tumor system was determined on Days 2, 4, 6 and 9 of growth. Studies included volume tumor growth, per cent labeled mitoses curves, and repeated injections of tritiated thymidine. It was possible to extrapolate the cytokinetic compartment values to Day 0 of growth. Results indicate that the growth fraction of the S-180 system remains close to 1 throughout its growth, with progressive lengthening of G₁, S and G₂ times. Cell loss is minimal through 6 days but becomes significant thereafter. A theoretical growth curve constructed from cytokinetic values is similar to the actual volume growth curve.