Identification of an alkaline ceramidase gene from Dermatophilus congolensis

A random amplified polymorphic DNA (RAPD) procedure was used to identify a specific 0.6 kb DNA fragment unique to Dermatophilus congolensis. This 0.6 kb fragment was evaluated as a specific DNA probe and used to design oligonucleotide primers for polymerase chain reaction (PCR) amplification. The nucleotide sequences adjacent to this DNA fragment were determined by inverse PCR allowing the identification of a 4.1 kb sequence. Analysis of this revealed a complete open reading frame (ORF) with a high similarity to an alkaline ceramidase from Pseudomonas aeruginosa. The molecular weight of the enzyme derived from the predicted amino acid sequence is 74,662 Da, its pI is 9.81. The predicted N-terminal sequence of the enzyme contains a signal sequence indicating that the enzyme is exported by the bacterium. Since ceramides have important protective and cell regulatory roles in the epidermis we suggest that this ceramidase may have a role in the pathogenesis of dermatophilosis. It is the first completely sequenced gene described for D. congolensis.     

EFFECT OF ROOTSTOCK ON SALT TOLERANCE OF LOQUAT: GROWTH AND MINERAL COMPOSITION

The salinity tolerance of loquat grafted onto anger or onto loquat was studied. The plants were irrigated using solutions containing 5, 25, 35, 50, or 70 mM sodium chloride (NaCl) for five months. Different parameters of vegetative growth were studied, all of them showing that plants grafted onto loquat are much less salinity-tolerant than those grafted onto anger. Thus, the concentration of NaCl that produced a growth reduction of 50% (C₅₀) for the growth parameters of the shoot was around 35 mM for loquat plants grafted onto loquat. With the NaCl levels employed, loquat-anger plants did not reach the C₅₀. Lower chloride (Cl^?) and sodium (Na⁺) uptake, higher potassium (K⁺)-Na⁺ selectivity and a lower reduction in the leaf magnesium (Mg²⁺) concentration for the loquat-anger combination can explain the higher salinity tolerance compared to loquat-loquat.     

EFFECT OF PEAT-REDUCED AND PEAT-FREE SUBSTRATES ON ROSEMARY GROWTH

The objective of this work was to study the use of four composts, obtained by agro-industrial, urban and green wastes, as growing media components on Rosmarinus officinalis L. Substrates were obtained by mixing each compost with peat in different proportions. Main physical and chemical characteristics of prepared substrates have been compared and, at the end of growing cycle, the biometric survey on main growing parameters and plant nutritional status was performed. The obtained results showed that substrates with 30% compost have main physical and chemical parameters comparable with those of the control. Best quality plants have been obtained substituting peat with 30% of compost, except with the olive mill compost. At the end, the green pruning compost can be recommended as growing media component (up to 50%) for the growth of Rosmarinus officinalis L., being able to determine high quality plants, together with an implemented plant nutrient efficiency.     

Progressive transfer to seawater enhances intestinal and branchial Na+-K+-ATPase activity in non-anadromous rainbow trout

Two sizes of rainbow trout [170 (4), 91 (3) g] were progressively transferred to seawater in January 1995 using three steps of 9, 20 and 28. Na+-K+-ATPase activity in gills, intestine and kidney, and plasma sodium and magnesium levels were assessed in response to changed external salinity. Gradual transfer to seawater had a stimulatory effect on gill and intestinal Na+-K+-ATPase activities after the transfer to 28, while its activity remained unchanged in the kidney. Plasma sodium content was not modified, while magnesium levels increased in response to increased external salinity. The size-dependent response to seawater transfer described by other authors was not detected in our experiments. The results are discussed in terms of long-term adaptation to seawater.     

Determinants of large-scale spatial distribution and seasonal microhabitat selection patterns of the endangered freshwater blenny Salaria fluviatilis in the Ebro River basin,Spain

1. The freshwater blenny Salaria fluviatilis is an endangered fish species with populations that are in rapid decline, largely owing to habitat degradation caused by human activity. This situation highlights the urgent need to develop measures for the conservation and recovery of the species based on a deep understanding of its specific habitat requirements.
2. In this study, spatial distribution and habitat selection patterns were investigated to determine the limiting factors for the species at different times of the year and at different spatial scales, from macro to microhabitats.
3. The presence of the freshwater blenny was assessed at 127 sites in the Ebro River basin, Spain, between 2002 and 2012. It was only detected at 25 sites, corresponding to the intermediate and lower reaches of medium-sized tributaries and in the main river, in accordance with the ecology of the species. Whether the species was present depended on the physicochemical, habitat and biological conditions of the study sites. Freshwater blenny was very sensitive to organic pollution and eutrophication, the deterioration of substrate composition and channel structure, and the degradation of aquatic and riparian vegetation.
4. Freshwater blenny showed a selective use of microhabitat locations with high current velocity, linked to gravel or cobble substrate. It was also observed that the species is capable of adapting its selection behaviour to the flow-mediated seasonal changes in its physical environment.
5. Although the results presented indicate that the species is not a microhabitat specialist, individual survival is likely to be dependent on the availability of key microhabitats, which must be protected against detrimental human activity.

     

Corticotropin-releasing factor-producing neurons in the rat activated by interleukin-1

Intraperitoneal administration of human recombinant interleukin-1 (IL-1) to rats can increase blood levels of corticosterone and adrenocorticotropic hormone (ACTH). The route by which IL-1 affects pituitary-adrenal activity is unknown. That the IL-1-induced pituitary-adrenal activation involves an increased secretion of corticotropin-releasing factor (CRF) is indicated by three lines of evidence. First, immunoneutralization of CRF markedly attenuated the IL-1-induced increase of ACTH blood levels. Second, after blockade of fast axonal transport in hypothalamic neurons by colchicine, IL-1 administration decreased the CRF immunostaining in the median eminence, indicating an enhanced release of CRF in response to IL-1. Third, IL-1 did not stimulate ACTH release from primary cultures of anterior pituitary cells. These data further support the notion of the existence of an immunoregulatory feedback circuit between the immune system and the brain.     

Tannins,Trypsin Inhibitors and Lectin Cytotoxicity in Tepary (<Emphasis Type="Italic">Phaseolus acutifolius</Emphasis>) and Common (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis>) Beans

This study compared the levels of antinutritional components and cytotoxic effect of extracts, from tepary (Phaseolus acutifolius) and common (Phaseolus vulgaris) beans. Antinutritional factors were evaluated by determining their effect on the viability of epithelial cells isolated from rat small intestine. The protein and carbohydrates content were similar in all the genotypes studied (20 and 60%, respectively). Common beans presented higher content of trypsin inhibitors, tannins and lectins than tepary beans. There was not a significant correlation between tannins and cooking time. However, water absorption and cooking time correlated significantly (p < 0.05). Considerable variation was observed in lectin activity (1302–18161 Ul/mg) of extracts from different beans. Tannins, lectins, trypsin inhibitors and fat content differed between bean varieties whereas protein content was similar. The percent cellularity on rat epithelial cells was significantly different among protein extracts from different bean cultivars and ranged between 53.5% and 87.4% (p < 0.05). These results suggest that the incorporation of tepary beans in the diet would not alter the current nutritional contribution of common beans or introduce adverse toxic effects. The agronomic characteristics of tepary beans make them attractive for cultivation. However, the harder to cook phenomenon may be a limiting factor that needs further consideration.     

A preliminary survey of viruses in pasture grasses in South Africa

Little work has been done in South Africa on the incidence of viruses in pasture grasses. The aim of this work was to carry out a survey of virus infections of some of the economically‐important pasture grasses in South Africa. Twelve winter and summer pasture grass species and one cereal forage crop species were collected from six different regions in early, mid‐ and late winter and summer. Plants were tested for virus(es) by means of symptomatology, transmission, dot‐blot immunoassays, Ouchterlony tests and electron microscopy. Serological tests indicate that Avena sativa from Roodeplaat and Bromus unioloides from Potchefstroom, Cedara and Nooitgedacht are positive for maize dwarf mosaic virus (MDMV). Lolium multiflorum from Cedara appears to be infected with two viruses, brome mosaic virus (BMV) and a potyvirus‐like agent, possibly ryegrass mosaic virus (RMV).     

Epidemiology of ryegrass mosaic virus in South Africa

The distribution and seasonal occurrence of ryegrass mosaic virus (RMV) in South Africa was determined. Italian ryegrass plants were collected from eight different research stations twice during the growing season in 1990 and 1991. Samples were tested for the presence of RMV by means of symptomology, electron microscopy, transmission and serology. The virus was found in only three of the tested sites, namely, Nooitgedacht (Ermelo), Cedara (Pietermaritzburg) and Glen (Bloemfontein). At Nooitgedacht and Cedara, the number of infected plants increased from mid‐season to late season, while at Glen, the number of infected plants was low at mid‐season and decreased even further by late season. It is suggested that the distribution and intensity of RMV may depend on regional temperature differences.     

2,3,7,8-Tetrachlorodibenzo-p-dioxin influences bovine herpesvirus 1 replication through upregulation of SIRT3 and cytoskeletal reorganization

Infection of kidney cells (MDBK) with Bovine Herpesvirus 1 (BoHV-1) is affected by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which accelerates BoHV-1-induced apoptosis and increases virus replication. Herein, to elucidate the mechanism through TCDD modifies BoHV-1 infection, we analyzed the modulation of a members of Sirtuin proteins family in MDBK cells. We found that mitochondrial SIRT3 was upregulated during infection. This change was accompanied by cytoskeletal rearrangements and cell extensions. All these trends were drastically modified by TCDD. We hypothesize that, taken together, these results might further clarify the processes responsible for the action of TCDD on the BoHV-1 replication, resulting in enhanced virus production.