Color stability and lipid oxidation of broiler breast meat from animals raised on organic versus non-organic production systems.

The aim of the present research was to evaluate the influence of organic and non-organic production systems on color stability and lipid oxidation of broiler meat Pectoralis major (PM) stored under refrigeration (4°C) for 9 days. PM samples from organic (ORG) and non-organic (NORG) production systems were compared based on physicochemical analyses (instrumental color, myoglobin concentration, metmyoglobin reducing activity (MRA), pH, and lipid oxidation) performed in 4 different trials (n = 4). In general, NORG broilers demonstrated higher (P < 0.05) b* and lipid oxidation values than ORG, whereas ORG samples exhibited increased (P < 0.05) MRA, ratio of reflectance at 630 per 580 nanometers (R 630/580), and a* values. The lower color stability observed in NORG samples can be partly due to lipid oxidation. Therefore, the production system can affect color and lipid stability of broiler breast meat during storage.

Colonization of cashew plants by Lasiodiplodia theobromae: microscopical features.

Lasiodiplodia theobromae is a phytopathogenic fungus causing gummosis, a threatening disease for cashew plants in Brazil. In an attempt to investigate the ultrastructural features of the pathogen colonization and its response to immunofluorescence labeling, light, confocal and electron microscope studies were conducted on different severity scale patterns of diseased plants. Lasiodiplodia-antisera was checked for cross reactivity against common cashew plants fungi. Optical microscopy analysis revealed a longitudinally sectioned hyphae located within the xylem vessels, showing an extensive hyphal development in the secondary xylem tissue. SEM images demonstrated that the fungus was found in some asymptomatic samples, particularly within the xylem vessels as confirmed by the optical images. Symptomatic sample images showed an extensive distribution of the fungus along the secondary xylem, within the vessels, infecting xylem parenchyma. A closer look in the secondary xylem parenchyma reveals a heavy and profuse invasion of the cells with a distinguishable cell wall disintegration and fully hyphae dispersal. There was no reactivity of Lasiodiplodia-antisera against mycelial extracts of Colletotrichum gloeosporioides, Phomopsis anardii and Pestalotiopsis guepinii. Following incubation of sections with the polyclonal antisera, the hyphae were intensely and regularly labeled. Rays, vessels and parenchyma cells were the preferred pathway for L. theobromae colonization. Artificial infection provides the information that the vascular cylinder is undoubtedly employed and used by the fungus for hyphae distribution. Immunofluorescence assay employed in situ was applied and the polyclonal antisera produced was able to recognize the fungus and proved to be a sensitive technique to detect it.

First Report of Dry Rot Caused by Fusarium oxysporum on Rose (Rosa spp.) in Brazil.

Roses are a high-value niche crop in the higher altitudes of northeastern Brazil. From July of 2007 and throughout 2008, severe stem rot and wilting of rose seedlings were observed in commercial fields in the São Benedito District, Ceará State, Brazil. Although economic losses due to the disease are unknown, it poses a threat to the growing rose industry in that region. Symptoms included leaf yellowing and abscission followed by plant collapse. Symptoms appeared earlier when grafted seedlings were produced during periods of high relative humidity (80 to 98%) and warm temperatures (20 to 31°C). In the laboratory, symptomatic seedlings were rinsed with distilled water, surface sterilized with 0.5% NaOCl, and incubated on PDA at 26 ± 2°C. Fusarium oxysporum was consistently isolated from infected scions and rootstocks. Identification of F. oxysporum was based on colony and conidia morphology obtained from single-spore colonies. Five 4-week-old rose ('Carola') seedlings were inoculated with a culture of fungus by spraying the needle-wounded scion with a spore suspension (1 × 105 CFU/ml). The spore suspension was obtained from a 1-week-old PDA culture incubated at 26 ± 2°C. Control seedlings were sprayed with sterile water. Inoculated seedlings were incubated for the first 48 h in a saturated humidity chamber. After 20 days at room temperature, the scion tissue of inoculated seedlings turned necrotic. Two symptomatic seedlings were placed in a saturated humidity chamber for 24 h to determine if fungal sporulation could be observed on the surface of the tissue. After 5 to 7 days, a white mycelium was observed over the necrotic tissue. Seedlings sprayed with sterile water remained symptomless. F. oxysporum was reisolated from symptomatic tissue. An isolate of F. oxyporum (No. 1484) was deposited in the Mycology Collection of Lavras (Minas Gerais State, Brazil). To our knowledge, this is the first report of F. oxysporum causing a disease on rose seedlings in Brazil.

First Report of a Bacterial Leaf and Fruit Spot of Cashew Nut (Anacardium occidentale) Caused by Xanthomonas campestris pv. mangiferaeindicae in Brazil.

In 2003 and 2004, leaves and young fruits of cashew nut plants showing an undescribed disease symptom were observed on plants of an early-dwarf clone in a commercial orchard in Ceará and Piauí states in northeastern Brazil. Initial symptoms consisted of angular, water-soaked, dark-to-black spots on the leaf and at the mid-rib vein surrounding the leaf veins. Eventually, lesions also extended from the mid-rib to the secondary veins, delineating the vein system of the leaf. In young, green fruits, symptoms were large, dark, oily spots surrounded by conspicuous water-soaked areas. A yellow-pigmented colony was consistently recovered from the lesions on nutrient yeast-extract dextrose agar medium (3 g of meat extract, 5 g of peptone, 10 g of dextrose, 5 g of yeast extract, and 18 g of agar per liter). Physiological tests revealed colonies that were gram negative, strictly aerobic, oxidase negative, catalase positive, lacking fluorescent pigmentation on King's B medium, urea hydrolase negative, and able to grow on yeast dextrose calcium carbonate medium yielding yellow colonies. These tests indicated that the bacterium belonged to the genus Xanthomonas. PCR amplification of bacterial DNA using RST2 (1) and Xcv3R (3) primers resulted in identical band patterns to mango isolates Xanthomonas campestris pv. mangiferaeindicae. Restriction fragment length polymorphism analysis of PCR-amplified products of six isolates of X. campestris pv. mangiferaeindicae was conducted with HaeIII and showed different profile patterns on agarose gel, indicating genetic variability among these isolates. Pathogenicity was demonstrated by gently piercing and misting cashew leaves with a bacterial suspension adjusted to 106 CFU/ml. Inoculated plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (29 ± 1°C). Control plants were misted with sterile water and treated the same way. After 8 days, foliar symptoms similar to those observed in the field developed on all inoculated plants, and reisolated bacteria were characterized and found to be X. campestris pv. mangiferaeindicae. Control plants remained symptomless. To our knowledge, this is the first description of commercially grown cashew plants as host to X. campestris pv. mangiferaeindicae in Brazil. This disease may pose a serious problem to the cashew-growing industry in Brazil. This bacterial pathogen has been reported on mangoes (Mangifera indica) and cashew in India (2) under the former name of Pseudomonas mangiferae-indicae. References: (1) R. P. Leite, Jr. et al. Appl. Environ. Microbiol. 60:1068, 1994. (2) M. K. Patel et al. Curr. Sci. 17:189, 1948. (3) L. C. Trindade et al. Summa Phytopathol. 33:16, 2007.

First Report of Black Branch Dieback of Cashew Caused by Lasiodiplodia theobromae in Brazil.

Cashew nut (Anacardium occidentale) is one of the most important cash crops of northeastern Brazil. A new disease, named here as black branch dieback, caused by Lasiodiplodia theobromae, was observed causing serious damage on as many as 30% of the trees in some orchards in both coastal and inland semiarid cashew-growing areas of Ceará and Piauí states of Brazil, respectively. The disease symptoms are first observed as darkened, elongated lesions on stems near the branch apexes of herbaceous tissues. Gum exudation is common from lesions, which expand rapidly to affect the entire branch, leading to branch death. Diseased plants were collected, and L. theobromae was consistently isolated from canker tissues. Fresh mycelial disks of the fungus were used for artificial inoculation of healthy plants. Shoots of young cashew plants were inoculated on the apex by inserting a 3-mm plug taken from actively growing colonies on potato dextrose agar into an incision made with a sterile scalpel. Agar plugs with no mycelium were placed into incised plant shoots to serve as controls. Plants were incubated in a greenhouse at 28°C. Symptoms developed within 15 days after inoculation. Artificially inoculated plants showed symptoms similar to those that were naturally infected. L. theobromae was consistently reisolated from inoculated plants. The disease seems to occur throughout the year, but it spreads faster during the rainy season. A contagious disease pattern within the orchard was observed with a decreasing gradient from the orchard perimeter to the interior of the field, suggesting an external source of primary inoculum. All improved dwarf cashew clones were susceptible, but the newly released clone END-189 was the most susceptible. Black branch dieback may reduce tree growth, nut yield, and eventually cause plant death. Plant susceptibility is not related to its age however; only herbaceous tissues are vulnerable to natural infection. A similar disease on floral shoots of cashew caused by L. theobromae was reported by Olunloyo and Esuruoso in Nigeria (1). To our knowledge, this is the first report of L. theobromae causing branch dieback in cashew orchards in Brazil. Reference: (1) O. A. Olunloyo and O. F. Esuruoso. Plant Dis. 59:176, 1975.