A semi-parametric model for lactation curves: development and application

We propose a semi-parametric model for lactation curves that, along with stage of lactation, accounts for day of the year at milk recording and stage of gestation. Lactation is described as having 3 different phases defined by 2 change points of which the second is a function of gestation stage. Season of milk recording is modelled using cosine and sine functions. As an application, the model is used to estimate the association between intramammary infections (IMI) dynamics as measured by somatic cell count (SCC) over the dry period and the shape of the lactation curve. Milk recording data collected in 2128 herds from England and Wales between 2004 and 2007 were used in the analysis. From a random sample of 1000 of these herds, smoothed milk production was used to test the behaviour of the model and estimate model parameters. The first change point was set at 60 days in milk. The second change point was set at 100 days of gestation or 200 days in milk when the latter was not available. Using data from the 1128 remaining herds, multilevel models were then used to model individual test-day milk production within lactations within herds. Average milk production at 60 days in milk for cows of parities 1, 2, 3 and greater than 3 were 26.9 kg, 31.6 kg, 34.4 kg and 34.7 kg respectively and, after this stage, decreases in milk production per 100 days milk of lactation were 3.1 kg, 5.1 kg, 6.3 kg and 6.7 kg respectively. Compared to cows that had an SCC below 200,000 cells/mL on both the last milk recording in a lactation and the first milk recording in the following lactation, cows that had an SCC greater than 200,000 cells/mL on their first milk recording after calving had an estimated loss of milk production of between 216 and 518 kg depending on parity. These estimates demonstrate the impact of the dynamics of SCC during the dry period on milk production during the following lactation.     

Geographical Variation and Factors Associated to Seroprevalence of Canine Leishmaniosis in an Endemic Mediterranean Area

This article retrospectively analyses the spatial distribution and dog‐ and environmental‐level risk factors associated to Leishmania infantum seroprevalence among 807 asymptomatic dogs in the Municipality of Crevillente in Alicante in southeast Spain in 1999. They represented 60% of the dogs in this 103 km² area, with a human census of 27 034 people and 90% lived in Crevillente town. The estimated seroprevalence (95% confidence interval) in 714 dogs ≥1‐year old was 22% (19–25) however; it was 12% (8–15) in town dogs and 0–100% in other administrative zones. High–medium seroprevalence zone clustered along a northeast–southwest fringe and around the town. They comprised the highest and driest inhabited part of the municipality, where farmland was interspersed by residential detached houses, whilst null–low seroprevalence zones included larger farmland extensions and two small rural villages. Predominant vegetation and ground soil type were bush, non‐irrigated fruit trees and conglomerate crust and sandstone in medium–high seroprevalence zones and irrigated grassland and fruit trees and colluvial deposits in null–low seroprevalence zones. Random effects logistic regression indicated that the prevalence of infection with L. infantum was higher for dogs sharing residence with infected dogs, increased until 5–6 years old and with body weight and was associated to increasing conglomerate crust and low surface water in the dog’s zone of residence. The study confirms that L. infantum infection is endemic in this part of Spain and shows that prevalence can vary significantly within a small area depending on specific demographic and environmental factors conditioning the habitat of the local L. infantum vector, Phlebotomus perniciosus. It suggests similar low‐scale variability is present in other geographically variable endemic areas and should be investigated to design Leishmaniosis risk maps and cost‐effective, evidence‐based, targeted control interventions.     

Structural characteristics of phosphoramide derivatives as urease inhibitors. Requirements for activity

Taking as a reference the structural characteristics of a set of compounds that act as jack bean ( Canavalia ensiformis) urease inhibitors, namely, phenylphosphorodiamidate (PPD), N- n-butylthiophosphorictriamide (NBPT), and N- n-butylphosphorictriamide (NBPTO), we have studied the structure-activity relationships of a series of phosphoramide derivatives for which the activity as urease inhibitors in both in vitro and in vivo assays is known. Molecular modeling studies were carried out, and the results highlighted the relevance of characteristics such as the presence of intramolecular hydrogen bonds, the volume of the fragment involved in the enzyme interaction, and the degree of conformational freedom as well as the HOMO orbital and atomic orbital contributions to the HOMO orbital, electron density, and PEM distributions on the activity of these compounds as urease inhibitors. These data, along with the preliminary docking study carried out, allow us to propose a union mode to the active site of the enzyme for these compounds.     

Non-invasive genetic monitoring involving citizen science enables reconstruction of current pack dynamics in a re-establishing wolf population

Background

Carnivores are re-establishing in many human-populated areas, where their presence is often contentious. Reaching consensus on management decisions is often hampered by a dispute over the size of the local carnivore population. Understanding the reproductive dynamics and individual movements of the carnivores can provide support for management decisions, but individual-level information can be difficult to obtain from elusive, wide-ranging species. Non-invasive genetic sampling can yield such information, but makes subsequent reconstruction of population history challenging due to incomplete population coverage and error-prone data. Here, we combine a collaborative, volunteer-based sampling scheme with Bayesian pedigree reconstruction to describe the pack dynamics of an establishing grey wolf (Canis lupus) population in south-west Finland, where wolf breeding was recorded in 2006 for the first time in over a century.

Results

Using DNA extracted mainly from faeces collected since 2008, we identified 81 individual wolves and assigned credible full parentages to 70 of these and partial parentages to a further 9, revealing 7 breeding pairs. Individuals used a range of strategies to obtain breeding opportunities, including dispersal to established or new packs, long-distance migration and inheriting breeding roles. Gene flow occurred between all packs but inbreeding events were rare.

Conclusions

These findings demonstrate that characterizing ongoing pack dynamics can provide detailed, locally-relevant insight into the ecology of contentious species such as the wolf. Involving various stakeholders in data collection makes these results more likely to be accepted as unbiased and hence reliable grounds for management decisions.

     

Fish Synucleins: An Update

Synucleins (syns) are a family of proteins involved in several human neurodegenerative diseases and tumors. Since the first syn discovery in the brain of the electric ray Torpedo californica, members of the same family have been identified in all vertebrates and comparative studies have indicated that syn proteins are evolutionary conserved. No counterparts of syns were found in invertebrates suggesting that they are vertebrate-specific proteins. Molecular studies showed that the number of syn members varies among vertebrates. Three genes encode for α-, β- and γ-syn in mammals and birds. However, a variable number of syn genes and encoded proteins is expressed or predicted in fish depending on the species. Among biologically verified sequences, four syn genes were identified in fugu, encoding for α, β and two γ (γ1 and γ2) isoforms, whereas only three genes are expressed in zebrafish, which lacks α-syn gene. The list of “non verified” sequences is much longer and is often found in sequence databases. In this review we provide an overview of published papers and known syn sequences in agnathans and fish that are likely to impact future studies in this field. Indeed, fish models may play a key role in elucidating some of the molecular mechanisms involved in physiological and pathological functions of syn proteins.     

A new haplotype of “Candidatus Liberibacter solanacearum” identified in the Mediterranean region

“Candidatus Liberibacter solanacearum”, a phloem-limited and Gram-negative bacterium that is spread from infected to healthy plants by psyllid insect vectors, is an economically important pathogen of solanaceous and carrot crops in the Americas, New Zealand and Europe. Three haplotypes of “Ca. L. solanacearum” have previously been described, two (LsoA and LsoB) in relation to solanaceous crops in the Americas and New Zealand and the third (LsoC) to carrots in Finland. Herein, we describe a fourth haplotype of this ‘Candidatus Liberibacter’ species (LsoD), also associated with carrots, but from Spain and the Canary Islands and vectored by the psyllid Bactericera trigonica. In addition, LsoC was confirmed in carrot and psyllid samples recently collected from Sweden and Norway. Phylogenetic analysis of the 16S rRNA gene suggests that two of the haplotypes, one in the Americas and the other in northern Europe are closer to each other in spite of a large geographic separation and host differences. Furthermore, during this study, potatoes with symptoms of zebra chip disease recently observed in potato crops in Idaho, Oregon and Washington states were analyzed for haplotype and were found to be positive for LsoA. This liberibacter haplotype was found in psyllids associated with the diseased potato crops as well. This finding contrasts with an earlier report of LsoB from psyllids in Washington which came from a laboratory colony originally collected in Texas.     

Simultaneous drying and densification of silver birch (Betula pendula L.) veneers: analysis of morphology,thickness swelling,and density profile

In this study, birch (Betula pendula L.) veneers were simultaneously densified and dried using a contact drying method at pressures of 1.5 and 3 MPa at 130 °C and compared with veneer dried in a laboratory-scale convective type dryer. Compression rate, thickness swelling, and the density profiles of the veneers were investigated. Furthermore, the microstructure of densified veneers was studied by scanning electron microscopy (SEM). A maximum veneer compression rate of 9 % was achieved at a pressure of 3 MPa. Under these conditions, the veneers were, on average, densified from 504 to 574 kg m^?3 (approximately 14 %). After water soaking, full set-recovery—recovery to the initial thickness—occurred. However, the swelling rate was lower for the densified veneer. Density profiles measurements showed that densification occurs throughout the veneers. The SEM images showed that the surface of the densified veneers were smoother, whilst no cracks were detected due to densification. Densification seemed to occur in vessels. Typically, rays were bent when there was a vessel nearby.