Characterizing the variation in aggressiveness and sporulation of the NA1 and EU1 lineages of Phytophthora ramorum in Oregon

Phytophthora ramorum, the cause of sudden oak death, is an invasive pathogen present in parts of coastal California and south-western Oregon forests. The majority of these forest infestations have been caused by the NA1 clonal lineage. In 2015, the EU1 lineage of P. ramorum was isolated from a tanoak (Notholithocarpus densiflorus) tree located in a mixed-conifer forest of Curry County, Oregon. In order to evaluate the threat to Oregon forests of the EU1 lineage relative to the established NA1 lineage, a series of experiments was conducted comparing aggressiveness and sporulation of NA1 and EU1 isolates on logs and seedlings in the growth chamber and forest. There was no significant difference in lesion size on logs inoculated with NA1 and EU1 isolates for any of the tree species tested. Across all seedling experiments differences among isolates within lineage, in terms of both aggressiveness and sporulation, were more commonly observed than differences among lineages. Site to site variation in tanoak sporulation, as measured by rain bucket baiting, appears to be correlated with the number of P. ramorum-positive seedlings detected at each site.     

Biosynthesis of Long-Chain Polyunsaturated Fatty Acids in Marine Gammarids: Molecular Cloning and Functional Characterisation of Three Fatty Acyl Elongases

Long-chain (C_20–24) polyunsaturated fatty acids (LC-PUFAs) are essential nutrients that are mostly produced in marine ecosystems. Previous studies suggested that gammarids have some capacity to endogenously produce LC-PUFAs. This study aimed to investigate the repertoire and functions of elongation of very long-chain fatty acid (Elovl) proteins in gammarids. Our results show that gammarids have, at least, three distinct elovl genes with putative roles in LC-PUFA biosynthesis. Phylogenetics allowed us to classify two elongases as Elovl4 and Elovl6, as they were bona fide orthologues of vertebrate Elovl4 and Elovl6. Moreover, a third elongase was named as “Elovl1/7-like” since it grouped closely to the Elovl1 and Elovl7 found in vertebrates. Molecular analysis of the deduced protein sequences indicated that the gammarid Elovl4 and Elovl1/7-like were indeed polyunsaturated fatty acid (PUFA) elongases, whereas Elovl6 had molecular features typically found in non-PUFA elongases. This was partly confirmed in the functional assays performed on the marine gammarid Echinogammarus marinus Elovl, which showed that both Elovl4 and Elovl1/7-like elongated PUFA substrates ranging from C₁₈ to C₂₂. E. marinus Elovl6 was only able to elongate C₁₈ PUFA substrates, suggesting that this enzyme does not play major roles in the LC-PUFA biosynthesis of gammarids.     

Biosynthesis of Polyunsaturated Fatty Acids in Marine Invertebrates: Recent Advances in Molecular Mechanisms

Virtually all polyunsaturated fatty acids (PUFA) originate from primary producers but can be modified by bioconversions as they pass up the food chain in a process termed trophic upgrading. Therefore, although the main primary producers of PUFA in the marine environment are microalgae, higher trophic levels have metabolic pathways that can produce novel and unique PUFA. However, little is known about the pathways of PUFA biosynthesis and metabolism in the levels between primary producers and fish that are largely filled by invertebrates. It has become increasingly apparent that, in addition to trophic upgrading, de novo synthesis of PUFA is possible in some lower animals. The unequivocal identification of PUFA biosynthetic pathways in many invertebrates is complicated by the presence of other organisms within them. These organisms include bacteria and algae with PUFA biosynthesis pathways, and range from intestinal flora to symbiotic relationships that can involve PUFA translocation to host organisms. This emphasizes the importance of studying biosynthetic pathways at a molecular level, and the continual expansion of genomic resources and advances in molecular analysis is facilitating this. The present paper highlights recent research into the molecular and biochemical mechanisms of PUFA biosynthesis in marine invertebrates, particularly focusing on cephalopod molluscs.     

Insulin,IGF-I,and muscle MAPK pathway responses after sustained exercise and their contribution to growth and lipid metabolism regulation in gilthead sea bream

Herein, we studied whether sustained exercise positively affects growth of gilthead sea bream by alterations in a) plasma concentrations of insulin and IGF-I, b) signaling pathways in muscle, or c) regulation of lipid metabolism. Specifically, we evaluated the effects of moderated swimming (1.5 body lengths per second; BL/s) on the circulating concentrations of insulin and IGF-I, morphometric parameters, and expression of genes related to lipid metabolism in gilthead sea bream (80–90 g BW). Exercise increased the specific growth rate (P < 0.05) and reduced the hepatosomatic index (P = 0.006). Plasma IGF-I concentrations increased in exercised fish (P = 0.037), suggesting a role for this endocrine factor in the control of muscular growth and metabolic homeostasis during swimming. The observed decrease in plasma insulin concentrations (P = 0.016) could favor the mobilization of tissue reserves in exercised fish. In this sense, the increase in liver fatty acid content (P = 0.041) and the changes in expression of peroxisome proliferator-activated receptors PPARα (P = 0.017) and PPARγ (P = 0.033) indicated a hepatic lipid mobilization. Concentration of glycogen in both white and red muscles was decreased (P = 0.021 and P = 0.017, respectively) in exercised (n = 12) relative to control (n = 12) gilthead sea bream, whereas concentrations of glucose (P = 0.016) and lactate (P = 0.0007) were decreased only in red muscle, indicating the use of these substrates. No changes in the glucose transporter and in lipoprotein lipase mRNA expression were found in any of the tissues studied. Exercised sea bream had decreased content of PPARβ mRNA in white and red muscle relative to control sea bream expression (P = 0.001 and P = 0.049, respectively). Mitogen-activated protein kinase phosphorylation was significantly down-regulated in both white and red muscles of exercised sea bream (P = 0.0374 and P = 0.0371, respectively). Tumor necrosis factor-α expression of white muscle was down-regulated in exercised gilthead sea bream (P = 0.045). Collectively, these results contribute to the knowledge base about hormonal regulation of growth and lipid metabolism in exercised gilthead sea bream.     

Physical characteristics and chemical composition of Lesser Rhea (Pterocnemia pennata) eggs from farmed populations

1. Eggs from 4 farmed populations of Lesser Rhea (Pterocnemia pennata) were studied to determine their physical and chemical characteristics. 2. None of the physical variables (weight of whole egg, yolk, albumen and shell; proportion of yolk based on egg content; proportion of shell based on entire egg weight; volume; density) showed significant differences between populations. 3. Among chemical variables, moisture, both saturated fatty acids (palmitic 16:0 and stearic 18:0), one monounsaturated fatty acid (palmitoleic 16:1), and one polyunsaturated fatty acid (arachidonic 20:4), did not differ between populations, whereas other variables (protein, lipid and ash contents; fatty acids: oleic 18:1, linoleic 18:2, linolenic 18:3; PUFA; PUFA/SFA; cholesterol) differed significantly.     

A comparison of traditional and quantitative analysis of acid-base and electrolyte imbalances in horses with gastrointestinal disorders

The purpose of this study was to compare traditional and quantitative approaches in analysis of the acid-base and electrolyte imbalances in horses with acute gastrointestinal disorders. Venous blood samples were collected from 115 colic horses, and from 45 control animals. Horses with colic were grouped according to the clinical diagnosis into 4 categories: obstructive, ischemic, inflammatory, and diarrheic problems. Plasma electrolytes, total protein, albumin, pH, pCO2, tCO2, HCO3-, base excess, anion gap, measured strong ion difference (SIDm), nonvolatile weak buffers (A(tot)), and strong ion gap were determined in all samples. All colic horses revealed a mild but statistically significant decrease in iCa2+ concentration. Potassium levels were mildly but significantly decreased in horses with colic, except in those within the inflammatory group. Additionally, the diarrheic group revealed a mild but significant decrease in Na+, tCa, tMg, total protein, albumin, SIDm, and A(tot). Although pH was not severely altered in any colic group, 26% of the horses in the obstructive group, 74% in the ischemic group, 87% in the inflammatory group, and 22% in the diarrheic group had a metabolic imbalance. In contrast, when using the quantitative approach, 78% of the diarrheic horses revealed a metabolic imbalance consisting mainly of a strong ion acidosis and nonvolatile buffer ion alkalosis. In conclusion, mild acid-base and electrolyte disturbances were observed in horses with gastrointestinal disorders. However, the quantitative approach should be used in these animals, especially when strong ion imbalances and hypoproteinemia are detected, so that abnormalities in acid-base status are evident.     

Differences in lymphocyte subpopulations from peripheral blood and lymphoid organs in natural caprine tuberculosis infection

Although the cell-mediated immune response is known to be a critical factor in host defence against intracellular mycobacterial infection, the different components of the T-cell response are unclear, particularly in caprine infection. In this study we examine the differences in the lymphocyte population of peripheral blood, spleen and mediastinal and superficial lymph nodes in 11 naturally infected goats showing positive reactions in the comparative tuberculine intradermal test. According to the different types of lesion showing, the goats were classified into proliferative or exudative tuberculosis. The results obtained by fflow cytometry analysis indicated that the main differences in peripheral blood were in the CD4 T-cell population, which decreased markedly in goats with exudative tuberculosis, while the CD8 and B cells increased in number. The gamma/delta T cells did not show significant differences in either type of tuberculosis, while interleukin-2 receptor cells decreased slightly in the exudative tuberculosis. The CD4:CD8 ratio was higher than 1 in goats with proliferative tuberculosis and lower than 1 in goats with exudative tuberculosis. In general, the lymphoid organs of the goats with exudative tuberculosis showed a significant increase in the number of CD8 T cells (CD4:CD8 ratio of less than 1) whereas no significant differences were observed in the CD4 T population between either type of tuberculosis.     

Cryptosporidiosis in chickens from southern Spain

Cryptosporidiosis in chickens from southern Spain is reported. Cryptosporidia were found in the trachea, esophagus, and epithelium of the bursa of Fabricius in chickens from different regions. In one flock, cryptosporidiosis was associated with respiratory problems and high mortality. In another flock, it was associated with low mortality and weight loss.     

Influence of paclobutrazol on water consumption and plant performance of Arbutus unedo seedlings

The purpose of this study was to examine the effect of paclobutrazol on the water consumption, plant water relations, gas exchange and development of strawberry tree seedlings (Arbutus unedo L.), to evaluate water resource management. Seedlings (8 cm in height) were subjected to a single drench of 60 or 100 mg of paclobutrazol and pot-grown in a greenhouse for 4 months. Untreated plants acted as control. Paclobutrazol reduced the development and improved the water status of the seedlings. At the end of the experimental period, it was seen that the two doses studied had reduced the plant dry weight, plant height and foliar development compared with the untreated plants. Paclobutrazol significantly reduced water consumption by 10% (60 mg) and 20% (100 mg) compared with the control. Plants treated with 100 mg showed the highest leaf water potential values at predawn. Paclobutrazol-treated plants presented turgor potential at values midday higher than control. This retardant stimulated a more efficient stomatal regulation, permitted an improved water status; however, it altered photosynthesis, reducing the plant growth. The lowered water consumption in paclobutrazol-treated plants was the result of a combination of mechanisms which reduced water loss through transpiration.