Dynamics of the free-living populations of gastrointestinal trichostrongyles of cattle in a natural grazing system in Guadeloupe (French West Indies)

The variations in the population size of trichostrongyle infective larvae (L3) in a cow-calf system were recorded for two years in Guadeloupe (humid and hot tropical climate). Calvings were pooled during the dry season for two herds and during the rainy season for two others. Each herd grazed three paddocks of natural pasture according to a rotational system (14 days of grazing per paddock). At the time the animals entered each paddock, the numbers of L3 on pasture were assessed around fecal pats (L3_ap) and within a 1 m radius of pats (L3_1rfp). Seventy-one regressor variables were tested to explain variations in the size of L3 populations: combinations of variables linked to animals (e.g. weight, fecal eggs, stocking rate) and combinations of ecological variables (e.g. rainfall, global radiation, herbage mass). L3_1rfp were highly correlated to L3_ap. However, when the mean global radiation during the third week after the entrance of animals exceeded 20 MJ m⁻² day⁻¹, L3_1rfp was undetectable even with large L3 burdens around pats. Multiple-component analysis and hierarchical classification used on regressor variables led to four classes which were characterized basically by fecal eggs and stocking rate, but not by climatic conditions. Within these classes, there was a limit of global radiation between 8 and 14 days after the entrance of animals; beyond this limit (20 MJ m⁻² day⁻¹), the L3_ap decreased from 1.3 to 27.1 times. The classification factor and global radiation factor explained 50–57% of the variance of L3_ap. From these results, it can be concluded that animal husbandry is just as important as climatic conditions in explaining the number of L3 on pasture in Guadeloupe. Global radiation, fecal eggs and stocking rates appeared to be useful in predicting the level of infectivity of pastures.     

Polycythemia and inappropriate erythropoietin concentrations in two dogs with renal T-cell lymphoma

Two dogs presented with suspected renal disease and polycythemia. Abdominal ultrasound examinations performed on both dogs revealed coalescing masses causing bilateral renomegaly. Serum erythropoietin (EPO) concentrations were physiologically inappropriate. Postmortem examinations revealed renal T-cell lymphoma in both dogs. One of the two dogs also had involvement of the liver and mesentery. EPO-immunohistochemistry on tissue samples demonstrated positive staining in tumor cells and occasional normal renal cells. This report illustrates that paraneoplastic EPO production may induce polycythemia. The pattern of EPO-immunohistochemistry staining suggested that the mechanism of production was due to tumor production of EPO and local hypoxia-induced EPO production from compression of normal renal cells and vasculature.     

First report of the Q biotype of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> in Argentina and Uruguay

Bemisia tabaci adults were collected from pepper and melon at different commercial production greenhouses in Argentina and Uruguay. The biotype status of adults was then established using cytochrome oxidase I gene (mtCOI) as molecular marker. Only the Q biotype was found on all plants sampled. This is the first report of the Q biotype in Argentina and Uruguay.     

Stored light in an optical fiber via stimulated Brillouin scattering

We describe a method for storing sequences of optical data pulses by converting them into long-lived acoustic excitations in an optical fiber through the process of stimulated Brillouin scattering. These stored pulses can be retrieved later, after a time interval limited by the lifetime of the acoustic excitation. In the experiment reported here, smooth 2-nanosecond-long pulses are stored for up to 12 nanoseconds with good readout efficiency: 29% at 4-nanosecond storage time and 2% at 12 nanoseconds. This method thus can potentially store data packets that are many bits long. It can be implemented at any wavelength where the fiber is transparent and can be incorporated into existing telecommunication networks because it operates using only commercially available components at room temperature.     

Asian carp farming systems: towards a typology and increased resource use efficiency

Resource use efficiency in Asian carp farming systems is analysed based on a survey of 2493 farms of nine countries. Multivariate classification of farms by intensity and diversity identified six farm types: four types of specialized aquaculture farms at different levels of intensity, and two types of integrated agriculture–aquaculture systems. Pond‐based, specialized semi‐extensive systems (using mainly inorganic fertilizers and feeds of off‐farm origin), and integrated semi‐intensive systems (using feeds and fertilizer of both on and off‐farm origin) are by far the most common types, accounting for 59% and 27% of all farms respectively. Specialized semi‐extensive systems also show the highest protein and nutrient (N and P) use efficiencies, and among the highest labour use efficiency. Super‐intensive cage farms are less efficient in nutrient and labour use, but provide very high returns to land and capital investment. On average, the aquaculture components of integrated agriculture– aquaculture systems are less nutrient, land, and labour efficient than specialized semi‐extensive systems. Integrated semi‐extensive systems (using organic fertilizers of on‐farm origin) are particularly inefficient across all indicators. Hence in practice, gains in overall resource use efficiency through on‐farm integration with agricultural production are constrained by the relative inefficiency of the aquaculture subsystems on integrated farms. Although such systems can likely be improved, integration as such is not a panacea to increasing resource use efficiency. Wide variation in resource use efficiency within all systems indicates potential for substantial efficiency gains through improved management regardless of the fundamental choice of system.     

Experimentally evolved populations of the potato cyst nematode Globodera pallida allow the targeting of genomic footprints of selection due to host adaptation

In the current agronomical context of pesticide use reduction, deciphering the genetic bases of pathogen adaptation to plant defences is of major importance to improve durability of resistance. Indeed, knowledge of virulence gene frequencies in pathogen populations could allow the prediction of resistance durability before deployment. Globodera pallida is a major pest of potato crops for which a promising resistance QTL, GpaV_vrn, has been identified in Solanum vernei. An experimental evolution study, in which G. pallida lineages evolved on resistant or susceptible potato genotypes for up to eight generations, previously showed that G. pallida was able to rapidly overcome GpaV_vrn resistance. However, it was not known if enough genetic mixing occurred in these lineages to be able to detect islands of differentiation in a genome scan approach. Here, this question was investigated using 53 polymorphic microsatellite markers distributed along the genome and three different tests based on genetic differentiation and heterozygosity. Eight outlier loci were identified, indicative of genomic regions putatively involved in host adaptation. Several loci were identified by multiple detection methods and/or in two independent adapted lineages. Some candidate genomic regions identified also seemed to be involved in overcoming resistance to nematodes in a plant genotype harbouring the same resistance QTL in a different genetic background. These results validate the feasibility of a genome scan approach on biological material coming from short experimental evolution, and encourage the use of a high coverage genome scan by whole genome resequencing.     

Scanning electron microscopic description of cellular activity and mineral changes in feline odontoclastic resorptive lesions

The cellular activity and changes in mineral composition of dental tissues involved in feline odontoclastic resorptive lesions were investigated. Teeth with at least 1 lesion (n = 10) were extracted from 10 different cats that were presented primarily for chronic gingivostomatitis and/or severe periodontal disease. Scanning electron microscopic methods were used to determine the presence of resorptive cells in 8 teeth while 2 teeth were evaluated for pathologic changes in dental mineral composition. Observations were complicated by the presence of organic wear on the dental surfaces, however resorptive cells could be clearly identified in feline odontoclastic resorptive lesions. Resorptive cells had morphologic features indicative of "osteoclast-like" cells or odontoclasts. Resorptive cell activity created a resorption area of darker dentin continuous with physiologic dentin. The darker dentin area seemed poorly mineralized and showed a significantly lower calcium/phosphorous ratio compared with adjacent physiologic denting in 1 tooth. A significantly higher level of magnesium combined with available carbonate ions may have increased the solubility in areas of darker dentin.     

Cholesterol granuloma as long-term complication of total ear canal ablation in a dog

A 13-year-old cocker spaniel presented with pain on opening the mouth. History of a previous left total ear canal ablation with lateral bulla osteotomy, left intermittent facial palsy and left intermittent head tilt suggested progression of a total ear canal ablation with lateral bulla osteotomy complication. Magnetic resonance imaging revealed a large mass arising from the tympanic bulla. Cytology of aspirates revealed a chronic suppurative inflammatory reaction and numerous cholesterol crystals. The mass was removed by surgical excision and an active drainage system was placed for a few days. The head tilt, facial palsy and apparent pain were resolved by the surgery. Physical examination was unremarkable nine months postoperatively. Bacterial cultures of the collected fluid were negative and histological examination confirmed the diagnosis of a cholesterol granuloma.