Notes on the biology of the tick Rhipicephalus bursa (Canestrini and Fanzago, 1877) in Israel

The seasonal distribution of the tick Rhipicephalus bursa in sheep has been studied during one year in two neighbouring flocks of Awassi sheep in an enzootic focus of sheep babesiosis. Rates of tick infestation on the two flocks were very different. Pre-imaginal stages were found on the sheep during the winter months of November-March while adult ticks appeared in the middle of April and persisted until the end of July. First clinical cases of babesiosis in sheep were diagnosed 2 weeks after finding the first adult ticks. The pre-imaginal stages were found mainly in the pinnas while adult ticks preferred in decreasing order the tail, body and head. Few adult ticks were found on the legs.     

Crystal structure of a lipid G protein-coupled receptor

The lyso-phospholipid sphingosine 1-phosphate modulates lymphocyte trafficking, endothelial development and integrity, heart rate, and vascular tone and maturation by activating G protein-coupled sphingosine 1-phosphate receptors. Here, we present the crystal structure of the sphingosine 1-phosphate receptor 1 fused to T4-lysozyme (S1P(1)-T4L) in complex with an antagonist sphingolipid mimic. Extracellular access to the binding pocket is occluded by the amino terminus and extracellular loops of the receptor. Access is gained by ligands entering laterally between helices I and VII within the transmembrane region of the receptor. This structure, along with mutagenesis, agonist structure-activity relationship data, and modeling, provides a detailed view of the molecular recognition and requirement for hydrophobic volume that activates S1P(1), resulting in the modulation of immune and stromal cell responses.     

Segmental axonopathy of Merino sheep in New Zealand

AIM: To investigate an axonopathy of Merino sheep that caused progressive hindlimb ataxia and slight to moderate paresis, with the purpose of understanding its pathogenesis.

METHODS: Tissues were fixed in buffered paraformaldehyde or paraformaldehyde and glutaraldehyde, processed into wax and epoxy resin, respectively, and examined by light and electron microscopy. Fresh frozen spinal cord and trigeminal nerve roots were subjected to homogenisation, centrifugation and two-dimensional electrophoresis. Selected protein spots were identified using matrix-assisted laser desorption ionisation (MALDI) mass spectrometry.

RESULTS. By light microscopy, there were large pale foamy spheroidal axonal swellings affecting peripheral as well as central axons. By electron microscopy, these were shown to contain many membrane-bound vesicles. The main abnormalities in expressed proteins involved cytoskeletal elements and myosin heavy chain, the latter interpreted as associated with the molecular motor myosin Va.

CONCLUSIONS: The disorder is the same as that described in Merinos in Australia as segmental axonopathy, and believed to have an inherited aetiology. The lesions and protein changes indicate abnormalities of the cytoskeleton, its relationship with the myelin sheath, and myosin Va molecular motor. The consequence appears to be abnormal axonal transport and inability to maintain the integrity of axons and their myelin sheaths.     

An investigation of Salmonella Fluntern illnesses linked to leopard geckos—United States, 2018

Reptile contact can result in zoonotic non‐typhoidal salmonellosis. In April 2018, Oregon Public Health Division contacted CDC about a cluster of four Salmonella serovar Fluntern (SF) illnesses in four states (OR, CA, IA, NY); patients reported contact with geckos, a popular reptile pet. PulseNet, the national molecular subtyping network of food‐borne disease surveillance, subsequently identified additional SF clinical isolates. Twelve cases in 11 states were identified; median age was 5 years (range: <1–58 years). Three patients were hospitalized; no deaths were reported. Of those with exposure information (n = 10), all reported reptile exposure; 9 (90%) specified contact with leopard geckos. No common source of geckos was identified from reported purchase locations. Los Angeles County (LAC) health officials isolated SF from one patient's leopard gecko. Five reptile/gecko isolates were identified from the USDA National Veterinary Services Laboratories (NVSL) from 2015 to 2018. Five countries responded to an Epidemic Intelligence Information System post by PulseNet; reptile isolate sequence data were received from Czech Republic. A clinical case from England was identified through the National Center for Biotechnology Information pathogen detection pipeline; the patient did not report contact with leopard geckos. Whole genome sequencing analysis revealed substantial genetic diversity between clinical and animal isolates; however, gecko and clinical isolates from LAC were highly related (1 allele difference). This investigation linking SF illnesses to leopard geckos highlights an important public health risk from pets. A better understanding of how geckos are distributed by the pet industry in the United States could improve traceability to points of origin and mitigate Salmonella transmission at gecko breeders. Earlier NVSL reports of SF isolates from geckos suggest the risk of human SF infection from geckos is not new. This investigation demonstrates a need to educate gecko breeders, retailers and gecko owners about the continued Salmonella infection risk from pet geckos.     

Effect of forage conservation method on microbial flora and fermentation pattern in forage and in equine colon and faeces

The influence of forage conservation method on microbial and chemical composition in forage and on colon content and faeces in horses fed with the forages was investigated. Hay (815 g DM/kg), haylage (548 g DM/kg) and silage (343 g DM/kg) was produced from the same grass crop and fed to four fistulated horses in a crossover study. Horses were sampled in right ventral colon and of faeces after a feeding period of 21 days (for each forage). Fermentation kinetics of right ventral colon was also studied on two subsequent days in each period, with sampling times immediately before and 2, 4, 8 and 12 h after the morning meal. Forage conservation method influenced microbial and chemical composition of the forages. Silage differed from haylage and hay in more variables than haylage differed from hay. However, the different forage types had similar influence on microbial and chemical composition of right ventral colon content and faeces in horses at Day 21, with the exception of counts of Streptococci which were highest when horses were fed with hay. However, interaction among forage types and sampling locations (right ventral colon and faeces) was also present for Streptococci as well as for pH. In general, pH was lower and counts of lactate utilizing and lactate producing bacteria were higher in faeces compared to right ventral colon. Fermentation kinetics in colon varied little among forage types and sampling times, and no interaction between forage types and sampling times were found, indicating that silage, haylage and hay had very similar fermentation kinetics in right ventral colon of horses. In conclusion, silage, haylage and hay produced from the same grass crop tended to produce similar responses in microbial and chemical composition in right ventral colon and faeces in horses fed with the forages.     

Molecular expression of caprine estrogen receptor gene 1 in reproductive and non‐reproductive tissues

During the last decades, physiological effects of oestrogens have been increasingly explored by scientists and biotechnologists. Estrogens exert a wide range of effects on a large variety of cell types. Oestrogen and its receptors are essential for sexual development and reproduction. Estrogen receptor alpha is a nuclear receptor activated by the hormone oestrogen. In male, ERα is encoded by the gene estrogen receptor gene 1 (ESR1), responsible for better fertility. The ESR1 is involved in the reabsorption of luminal fluid during the transit of spermatozoa from the testis to the head of the epididymis which is important for their survival and maturation during epididymal storage. The absence of ESR1 leads to reduced epididymal sperm content, reduced sperm motility and fertilizing ability. Therefore, this is a good startby to study the expression pattern of estrogen receptor 1 gene in high‐fertile (G1) and low‐fertile (G2) bucks of Jamunapari and Barbari breeds identified on the basis of seminal quality traits and fertility trials. RNA was extracted from the tissues by TRIzol method. The identification and expression pattern of caprine ESR1 gene was analysed by real‐time PCR (Roche LC‐480). Our work shows that the relative quantification by RT‐PCR indicates more fold in head of epididymis as compared to spleen of caprine ESR1 gene. Furthermore, the RT‐PCR indicated that fertile bucks of Jamunapari breed have more fold value as compared to Barbari breed in respect of reproductive organ.     

The theropod ancestry of birds: new evidence from the late cretaceous of madagascar

A partial skeleton of a primitive bird, Rahona ostromi, gen. et sp. nov., has been discovered from the Late Cretaceous of Madagascar. This specimen, although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral articulations. Rahona has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups Troodontidae and Dromaeosauridae. A phylogenetic analysis places Rahona with Archaeopteryx, making Rahona one of the most primitive birds yet discovered.