Comprehensive diversity assessment of walnut-associated xanthomonads reveal the occurrence of distinct Xanthomonas arboricola lineages and of a new species (Xanthomonas euroxanthea) within the same tree

Xanthomonas arboricola pv. juglandis (Xaj) is the aetiological agent of walnut diseases causing economic losses on walnut production worldwide. This phytopathogen is spread around the world where walnuts are produced and has a considerable genetic diversity. Using a comprehensive sampling methodology, focusing on factors that could influence the diversity of walnut-colonizing Xaj in Portugal, this work provides new insights on xanthomonad populations on walnut. Genetic diversity was assessed by multilocus sequence analysis (MLSA) and dot blot hybridization patterns on 131 Xanthomonas isolates obtained from 64 walnut trees considering epidemiological metadata such as year of isolation, distinct bioclimatic regions, production regimes, and host-related features. The results showed that the majority of isolates were split into 17 lineages of Xaj, while the other isolates clustered in four MLSA groups that did not include Xaj strains. These four groups were represented by three lineages of X. arboricola, and 11 lineages of Xanthomonas spp., including strains assigned to the recently proposed new species Xanthomonas euroxanthea. Furthermore, distinct Xaj, X. arboricola, and Xanthomonas spp. were isolated from the same walnut tree, suggesting possible genetic admixture within the same host. Phylogenetic analysis through geoBurst revealed the high diversity of these Xanthomonas spp. populations. Assessment of type III effector genes gave the indication that some Xanthomonas spp. strains were nonpathogenic on walnut, with the exception for X. euroxanthea CPBF 424. Altogether, these findings add to the thorough characterization of walnut-associated xanthomonads in Portugal, providing a comprehensive snapshot of the current diversity that could contribute to risk assessment analysis and improve phytosanitary control.     

Protection from challenge following administration of a canarypox virus-vectored recombinant feline leukemia virus vaccine in cats previously vaccinated with a killed virus vaccine

OBJECTIVE: To compare protection against FeLV challenge obtained following administration of 2 doses of an adjuvanted, chemically inactivated, whole FeLV (FeLV-k) vaccine with protection obtained following administration of 1 dose of an FeLV-k vaccine followed by 1 dose of a canarypox virus-vectored recombinant FeLV (rCP-FeLV) vaccine. DESIGN: Prospective study. ANIMALS: Thirty-two 9-week-old domestic shorthair cats. PROCEDURE: Cats received 2 doses of the FeLV-k vaccine SC, 21 days apart (n = 11); 1 dose of the FeLV-k vaccine SC and, 21 days later, 1 dose of the rCP-FeLV vaccine transdermally (11); or 2 doses of physiologic saline (0.9% NaCl) solution (control; 10). Four weeks after the second vaccine dose, all cats were challenged with FeLV by means of oronasal administration. Blood samples were collected at weekly intervals beginning 21 days after challenge, and serum was tested for FeLV antigen. RESULTS: All 10 control cats became persistently infected (ie, FeLV antigen detected in > or = 3 consecutive serum samples) following FeLV challenge, whereas only 1 of 11 cats that received 2 doses of the FeLV-k vaccine and none of the 11 cats that received 1 dose of the FeLV-k vaccine and 1 dose of the rCP-FeLV vaccine did. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that protection against FeLV challenge obtained following SC administration of a single dose of an FeLV-k vaccine followed, 21 days later, by transdermal administration of a single dose of an rCP-FeLV vaccine was similar to that obtained following SC administration of 2 doses of the FeLV-k vaccine 21 days apart.     

Modulation of the innate immune response,antioxidant system and oxidative stress during acute and chronic stress in pacu (Piaractus mesopotamicus)

Fish Physiology and Biochemistry - Stress is an energy-demanding process, as well as the responses of the innate immune system, that impose a metabolic overload on cellular energy production, which...     

Potassium Fertilization in Sugarcane Ratoon Yield Grown in a Tropical Region

ABSTRACT

Potassium (K) is closely associated to the improvement of sugarcane quality, acting in the conversion of reducing sugar (RS) to recoverable sugars (TRS). The present study aimed to evaluate the effect of different levels of K-fertilization on the yield and technological quality of sugarcane ratoons grown under edaphoclimatic conditions in the Brazilian central region. The experiment was carried out using the sugarcane variety CTC-4, in a Distrofic Latosols, medium texture (270 g clay kg^?1). The study was arranged in a randomized complete block design, with five treatments (0; 50; 100; 150 and 200 kg K₂O ha^?1), and five replicates. Potassium content in soil and plant, biometric variables, stalk yield and the technological quality at harvest were evaluated. The 200 kg ha^?1 dose increased the K content in 160, 156, 56 and 3% in 0–0.20 and 0.20–0.40 m layers at 180 and 360 days after budding (DAB), respectively, promoting greater absorption of the nutrient by plants (X ? = 15.22 g kg^?1). The higher potassium absorption reflected in yield gains, with an increasing of 7.9%, compared to the control treatment, yielding 100.37 t ha^?1. However, soil K fertilization did not affect the technological quality of the sugarcane ratoon.

Abbreviations: K: potassium; RS: reducing sugars; TRS: recoverable sugars; DAB: days after budding; SB: Sum of Bases; CEC: Cation Exchange Capacity; V: Saturation Base; Kcl: potassium chloride; AWC: Available water capacity; PC: Pol percent in sugarcane; Brix: total soluble solids; dRYL: Dystrophic Red Yellow Latosol; eRYA: Eutrophic Red Yellow Argisol.     

A new steroidal saponin with antiinflammatory and antiulcerogenic properties from the bulbs of Allium ampeloprasum var. porrum

A new steroidal saponin was isolated from the bulbs of Allium ampeloprasum var. porrum L. On the basis of chemical evidence, comprehensive spectroscopic analyses and comparison of known compounds, its structure was established as (3β,5α,6β,25R)-6-[(β-d-glucopyranosyl)oxy]-spirostan-3-yl O-β-d-glucopyranosyl-(1→2)-O-[β-D-glucopyranosyl-(1→3)]-β-d-galactopyranoside (1). Results of the present study indicated that the steroidal saponin showed haemolytic effects in the in vitro assays and demonstrated antiinflammatory activity and gastroprotective property using in vivo models.     

First successful frozen semen of the maned wolf (Chrysocyon brachyurus)

This study aimed to describe successful cryopreservation of sperm from maned wolves (Chrysocyon brachyurus). Three ejaculates from 2 maned wolves were collected by digital manipulation of the penis and evaluated subjectively, centrifuged and frozen in BotuCrio^® (Botupharma, Botucatu, Brazil) or Tris–yolk egg extender. Spermatozoa were thawed at 37ºC/30s or 70ºC/4s and evaluated for kinetics, morphology, plasma and acrosome membrane integrity, mitochondrial potential, hydrogen peroxide, superoxide anion and lipid peroxidation. From 5 thawed samples, two had sperm total motility >55% (56.0% and 64.0%) and progressive motility ~35% (35% and 40%), both frozen with Tris–yolk egg. Plasma and acrosome membrane integrity decreased and percentage of sperm defects increased post-thawing. We concluded that is possible to freeze spermatozoa from maned wolves using semen collection and processing methods applied for domestic dogs.     

Protein supplementation to early lactation dairy cows grazing tropical grass: Performance and ruminal metabolism

This experiment was designed to evaluate the effects of different concentrate crude protein (CP) concentration on performance, metabolism and efficiency of N utilization (ENU) on early-lactation dairy cows grazing intensively managed tropical grass. Thirty cows were used in a ten replicated 3 × 3 Latin square design. The treatments consisted of three levels of concentrate CP: 7.9%, 15.4%, and 20.5% offered at a rate of 1 kg (as-fed basis)/3 kg of milk. The cows fed low and medium CP had negative balance of rumen degradable protein and metabolizable protein. Increasing CP tended to linearly increase DMI, 3.5% FCM and milk casein, and linearly increased the yields of milk fat and protein. Increasing CP linearly increased the intake of N, the concentration of rumen NH₃–N, and the losses of N in milk, urine, and feces. Increasing dietary CP linearly increased the molar proportion of butyrate but had no effect on the other rumen VFAs and no effect on microbial yield. In conclusion, feeding a concentrate with 20.5% of CP to early-lactation dairy cows grazing tropical grasses, leading to a 17.8% CP diet, tended to increase DMI, increased the yield of 3.5% FCM and the milk N excretion, and decreased ENU by 32%.