Protection, immune responses and side effects in Atlantic salmon (Salmo salarL.) vaccinated against furunculosis by different procedures

In an experimental trial lasting approximately 6 months, 10 different vaccination regimes against furunculosis were studied in Atlantic salmon pre-smolts. Single and repeated administration of vaccine by the intraperitoneal (i.p.), immersion or oral route, and revaccination by combinations of these methods, were tested. In challenge assays initiated 8 and 16 weeks after vaccination, fish injected once with a trivalent vaccine, and fish injected twice with a monovalent vaccine, both containing aluminium phosphate as adjuvant, were moderately protected. Non-injection vaccination protocols consistently failed to protect the fish. Compared with unvaccinated fish, protected groups showed elevated antibody responses toAeromonas salmonicidaantigens throughout the study. Increasedin vitroproliferation of head kidney leucocytes from i.p. vaccinated fish was found 16 weeks after vaccination. The use of a polyvalent vaccine preparation, and revaccination by injection or the oral route improved both immune responses and survival, compared to a single inoculation of monovalent vaccine. In all groups subjected to i.p. administration of vaccine, minor to moderate intraperitoneal lesions were found. In conclusion, i.p. administration of adjuvanted vaccine, preferably in a polyvalent formulation, is the optimal method of inducing anti-furunculosis immunity in Atlantic salmon, and is apparently necessary for an effective immunoprophylaxis of salmonid fish against furunculosis.     

X-RAY MICROANALYSIS IN CELL BIOLOGY AND CELL PATHOLOGY

Electron probe X-ray microanalysis has been used for the last 25 years by biologists to obtain information about the distribution of elements at the cell and tissue level. During this period, progress has mainly been made through the development of more adequate techniques for specimen preparation (mainly low temperature techniques) and quantitative analysis, so that accurate analysis of the physiologically important cellular ions can be carried out. Use ofin vitrosystems and cell cultures may further increase the number of problems to which X-ray microanalysis can be applied. Among the numerous applications of X-ray microanalysis in cell biology and cell pathology, applications in the areas of epithelial ion transport, the role of calcium in secretory and contractile cells, and the role of ions in cell proliferation and cancer are discussed in more detail.     

Phylogenetic relationships among marsupial frog genera (Anura: Hylidae: Hemiphractinae) based on evidence from morphology and natural history

We reassess the phylogenetic relationships of genera of hemiphractine hylid frogs (Marsupial Treefrogs) and discuss the evolution of several distinctive characters within this group using parsimony analysis. Fifty-one morphological and life-history characters were sampled from two species of Cryptobatrachus , three species of Flectonotus , 17 species of Gastrotheca , all five species of Hemiphractus , and one species of Stefania as the ingroup and three hyline, one phyllomedusine, and one pelodryadine species as outgroups. Our results support the mon-ophyly of Flectonotus, Cryptobatrachus , and Hemiphractus. Gastrotheca is paraphyletic with respect to Hemiphractus , dorsal pouches were lost in the ancestor of Hemiphractus. Direct development is a synapomorphy for Hemiphractinae and tadpoles were regained independently several times. These results stand in stark contrast to the prevailing paradigm regarding marsupial frog relationships.     

Illumination of cryptic species boundaries in long-tailed shrew tenrecs (Mammalia: Tenrecidae; Microgale), with new insights into geographic variation and distributional constraints

The increasing use of mitochondrial DNA (mtDNA) to explore and test species limits among morphologically similar species is potentially compromised by phenomena poorly reflective of organismal history and speciation, including (but not limited to) stochastic lineage sorting and gene flow. In situations where molecular data are only available from a single gene or linkage partition (e.g. mtDNA), corroboration of suspected species boundaries should be sought from independent lines of evidence, such as morphology. Recent attempts to delimit species using mtDNA and morphology have either implicitly or explicitly ignored the possibility that distinct species can occur in direct sympatry throughout much of their range, presumably because such situations are believed to be rare. We examined phylogenetic relationships within the long‐tailed shrew tenrecs (Mammalia: Tenrecidae; Microgale spp.) from Madagascar. Current taxonomy recognizes two broadly sympatric species, though as many as six have been described. Given that alpha taxonomy within shrew tenrecs has been controversial, and that patterns of morphological variation can be especially difficult to assess for this group, some authors have suggested that additional cryptic species may exist. To examine this possibility, we conducted a phylogenetic study using the mitochondrial NADH dehydrogenase subunit 2 gene and a morphometric analysis of 29 craniodental, postcranial, and external measurements from a broad geographical sample of long‐tailed shrew tenrecs. The two data sets were nearly perfectly congruent in identifying four groups that can be classified as species, thereby doubling the currently recognized number of species. We present previously unrecognized distributional evidence consistent with our conclusions and provide an empirical example of how a revised understanding of species limits alters inferences of geographic variation and species coexistence, particularly with respect to fine‐scale habitat partitioning. The results of this study suggest that certain species pairs, previously assumed to be single species occupying broad elevational ranges, are actually reproductively isolated units that are partitioning their environment along elevational lines. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 1–22.     

Movement of 14C- and 11C-labelled Assimilate in Wheat Leaves: the Effect of IAA

The rate of translocation of naturally-loaded, radiolabelledassimilate has been studied in leaves of wheat treated withIAA. The velocity was measured directly by following the movementof ¹¹C-labelled material along the leaf. The kinetics of translocationwere also estimated by using a two-compartment model to calculatethe rate constant of disappearance of ¹⁴C from the fed area.IAA was applied at three different sites on the leaf and atvarious times up to 24 h before ¹⁴CO₂ feeding. No effects ofIAA were observed on: (1) direction and velocity of transport;(2) loading of assimilate into the phloem; or (3) the site andkinetics of unloading. These results are discussed with referenceto the movement of IAA along the transport path and the useof different tissues as experimental systems.     

Carbonic Anhydrase in the Accessory Boring Organ of the Gastropod, Urosalpinx

Carbonic anhydrase (CA), the enzyme which catalyzes the reactionCO₂+H₂OH₂CO₃, was found in both active and resting accessoryboring organs (ABO) of Urosalpinx, using a modification of theWaldeyer and Häusler (1959) technique in which the tissuesection is floated on the substrate solution. The intense reactivityof this gland exceeded the activity of other pedal tissues ofthis muricid gastropod. The ventral pedal gland of the femalealso exhibited strong activity, but theconcentration in thistissue was not as intense as that observed in the ABO. No discernible differences between the microvilli of restingand boring ABOs were noted after fixation in acetone, formalin,or glutaraldehyde. However, notable nuances in reactivity ofthe pedal structures occurred when the comparative effect offixatives was evaluated. All variations of the immersion technique, as opposed to flotationprocedures, exhibited a strong stain only in the microvilliof active ABOs, and little or no activity in resting ABOs. Thisdifference between active and resting ABOs (immersion techniqueonly) appears to be due to the binding (chelation) of calciumwith subsequent replacement of cobalt (probably as a carbonatecomplex) in the substrate. The markedly greater CA activity in the ABO, relative to othersecretory tissues inthe snail, suggests a vital role for thisenzyme in the process of penetrating shell. Thelow pH of thesecretion from the active ABO during boring indicates that atleast one phase of the boring process is a chemical reactionassociated with production of acid.     

Variation in Nitrate Reductase Activity in Lolium

Nitrate reductase activity was studied in the leaves and rootsof Lolium perenne. Growth temperatures of 8, 15, or 20 °Cdid not affect activity, but the same temperatures during assayhad differential effects on the nitroso couple used to measureenzyme activity. Activity increased with increasing light intensity,reaching a high plateau value at around 40 W m^–2. Nitratecontent of leaves, also measured in this experiment, did notvary significantly with different light intensities. Increasingnitrate in the nutrient solution up to 0.5 mM N also increasedactivity. Adding ammonium chloride at similar levels to thenitrate caused no marked repression of activity. Removal ofnitrate from the nutrient solution decreased enzyme activitywithin 24 h. Marked diurnal fluctuations occurred in activity,apparently in response to light intensity, since the nitratelevel in the plant varied little. The enzyme activity of rootswas much less than that of leaves. In the parents and progeny from a half diallel cross, the parentalgenotypes differed significantly in activity, but the numberof families involved was too small for the regression of progenyon parents (b = 1.74) and the correlation coefficient (r = 0.44NS) to achieve significance. In this experiment a significantpositive regression was obtained between nitrate reductase activityand dry matter yield.     

A REPORT ON VARIATION IN pH AND MICROSCOPICAL COUNT OF BACTERIA IN A PIT OF GRASS SILAGE

SUMMARY: Ignoring wasted material at the surface and sides, the variation in pH in six months old pit silage was smaller from side to side than from top to bottom. At the 2-foot level, where the best quality silage was found, variation was very slight. A correlation was found between pH and the logarithm of the microscopical count of bacteria, the total number of bacteria falling with decreasing pH.     

The Partitioning of Photosynthetically Fixed Carbon in the Leaf Blade and Leaf Sheath of Poa pratensis L.

The partitioning of photosynthetically fixed carbon betweencarbohydrate fractions and the processes of export and storagewere compared in mature leaf blades and sheaths of the grassPoa pratensis L. Most of the fixed carbon was destined for exportfrom the leaf blade with only 1% of the carbon fixed duringthe photoperiod being stored after 24 h. Although most of theassimilates imported to the sheath from the blade were subsequentlyexported, there was some unloading and storage of assimilates.Autoradiography was used to compare the translocation of ¹⁴C-labelledassimilates through non-fed areas of leaf blade and sheath andrevealed that the veins in the sheath showed a greater capacityfor storage of assimilates compared to the leaf blade. Biphasickinetics of sucrose and glucose uptake were observed in segmentsof leaf blade and sheath. Although similar carriers for eachof the sugars appear to exist in the blade and sheath, the rateof uptake via these carriers was significantly lower in thesheath compared to the blade. Assuming that unloading proceedsvia a symplastic pathway, it would appear that the conversionof sucrose to starch in the sheath could be an important meansof regulating unloading and in determining sink strength ofthe sheath. It is concluded that although the net amount ofsugars unloaded in the sheath is small, the storage of assimilatesin the vein network could be an important means of bufferingchanges in sucrose concentration in the translocate during periodsof fluctuating assimilation. Key words: Poa pratensis, autoradiography, sugar uptake, leaf blade, leaf sheath