Crystal structure of a shark single-domain antibody V region in complex with lysozyme

Cartilaginous fish are the phylogenetically oldest living organisms known to possess components of the vertebrate adaptive immune system. Key to their immune response are heavy-chain, homodimeric immunoglobulins called new antigen receptors (IgNARs), in which the variable (V) domains recognize antigens with only a single immunoglobulin domain, akin to camelid heavy-chain V domains. The 1.45 angstrom resolution crystal structure of the type I IgNAR V domain in complex with hen egg-white lysozyme (HEL) reveals a minimal antigen-binding domain that contains only two of the three conventional complementarity-determining regions but still binds HEL with nanomolar affinity by means of a binding interface comparable in size to conventional antibodies.     

Contrasting climate velocity impacts in warm and cool locations show that effects of marine warming are worse in already warmer temperate waters

Species responses to climate change are often measured at broad spatiotemporal scales, which can miss the fine-scale changes that are most relevant to conservation and fisheries management. We develop a scaleable geostatistical approach to assess how juvenile and adult fish distributions have been shaped by changes in bottom temperature and dissolved oxygen over a recent decade of warming in the northeast Pacific. Across 38 demersal fishes, biomass trends were associated negatively with warming and positively with dissolved oxygen, but when trends in both biomass and climate were converted to velocities—the speed and direction a population would have to move to maintain consistent conditions—the effect of temperature change differed depending on local conditions. In the warmest locations, warming velocities were associated with negative biotic velocities for 19 of 69 species-maturity combinations, and yet were almost always associated with stable or positive biotic velocities in the coolest locations (64 of 69). These spatially consistent biomass declines (negative biotic velocities) in the warmest locations and increases in cooler locations suggest a redistribution of species with the potential for new ecological and fisheries interactions. After controlling for temperature, the more spatially consistent effects of dissolved oxygen were often negative, suggesting a mechanism other than hypoxia avoidance—potentially changes in primary production. Our approach identifies the species and locations that are most sensitive to observed changes in the environment at any scale, thus facilitating future vulnerability assessments.     

Vernalization promotes flowering of a heat tolerant Calandrinia while long days replace vernalization for early flowering of Brunonia

The flowering responses of Brunonia australis (blue pincushion) and Calandrinia sp. to vernalization, photoperiod, temperature and plant age were investigated to provide a foundation for manipulating flowering in these potential potted plants. Plants were vernalized at 4.8 °C for 0, 3 or 6 weeks at the plant age of 1–4 or 8–14 leaves. Following vernalization, plants were grown at 25/10 or 35/20 °C (day/night) under short days (11 h, ambient daylight averaged 380 ± 44 μmol m⁻² s⁻¹) or long days (16 h) provided by an additional 5 h night break (21:00–2:00 h at <4.5 μmol m⁻² s⁻¹ from incandescent lamps), for 85 days. This is the first work to investigate flowering of these ornamental species. Both species showed enhanced flowering following vernalization and a quantitative requirement for long days. The reduction of the time until the first visible inflorescence (Brunonia) or flower (Calandrinia) buds by 8–13 days was affected by vernalization for 3 or 6 weeks, respectively. Long days were effective for reducing the time to first visible floral bud and increasing the number of inflorescence or flowers per plant for both species. For Brunonia, LDs replaced vernalization when applied to plants with 1–4 leaves. Raising temperature from 25/10 to 35/20 °C increased the number of flowers per plant of Calandrinia by 2–2.5-fold for plants with 1–4 or 8–14 leaves respectively.     

Pre-implantation exogenous progesterone and pregnancy in sheep. Ⅱ. Effects on fetalplacental development and nutrient transporters in late pregnancy

Background: Administration of progesterone(P4) to ewes during the first 9 to 12 days of pregnancy accelerates blastocyst development by day 12 of pregnancy, likely due to P4-induced up-regulation of key genes in uterine epithelia responsible for secretion and transport of components of histotroph into the uterine lumen. This study determined if acceleration of blastocyst development induced by exogenous P4 during the pre-implantation period affects fetal-placental development on day 125 of pregnancy. Suffolk ewes(n = 35) were mated to fertile rams and assigned randomly to receive daily intramuscular injections of either corn oil vehicle(CO, n = 18) or 25 mg progesterone in CO(P4, n = 17) for the first 8 days of pregnancy. All ewes were hysterectomized on day 125 of pregnancy and: 1) fetal and placental weights and measurements were recorded; 2) endometrial and placental tissues were analyzed for the expression of candidate mRNAs involved in nutrient transport and arginine metabolism; and 3) maternal plasma, fetal plasma, allantoic fluid, and amniotic fluid were analyzed for amino acids,agmatine, polyamines, glucose, and fructose.Results: Treatment of ewes with exogenous P4 did not alter fetal or placental growth, but increased amounts of aspartate and arginine in allantoic fluid and amniotic fluid, respectively. Ewes that received exogenous P4 had greater expression of mRNAs for SLC7 A1, SLC7 A2, SLC2 A1, AGMAT, and ODC1 in endometria, as well as SLC1 A4, SLC2 A5, SLC2 A8 and ODC1 in placentomes. In addition, AZIN2 protein was immunolocalized to uterine luminal and glandular epithelia in P4-treated ewes, whereas AZIN2 localized only to uterine luminal epithelia in CO-treated ewes.Conclusions: This study revealed that exogenous P4 administered in early pregnancy influenced expression of selected genes for nutrient transporters and the expression of a protein involved in polyamine synthesis on day 125 of pregnancy, suggesting a ‘programming' effect of P4 on gene expression that affected the composition of nutrients in fetal-placental fluids.     

Assessment of on-screen measurements, magnification, and calibration in digital radiography

Objective-To compare calibration methods for digital radiography in terms of measurement accuracy and interobserver variability. Design-Prospective study. Sample-Digital radiographic images of a 155-mm-long Steinmann pin. Procedures-Measurement of pin length on digital radiographs was determined with a 25.4-mm-diameter calibration ball and commercially available software program via 3 calibration methods (ie, no calibration, autocalibration, and manual calibration). Digital radiographs of the calibration ball and pin were obtained with each placed at various vertical heights from the table (7 heights) and horizontal distances from the center of the beam (4 distances). Measurements of pin length on digital radiographs were made by 4 observers who were blinded to the orientation of the calibration ball and pin. Results-Pin lengths obtained by each calibration method were significantly different from each other and from the true value. Manual calibration was the most accurate. There was no significant interobserver variability in measurements. There was no significant change in measurements when the calibration ball was moved horizontally, but pin length measurements changed significantly when the ball was moved vertically (away from the table) with an approximate magnification error of 1% per centimeter of distance between the calibration ball and pin. Conclusions and Clinical Relevance-For digital radiography, manual calibration is recommended to achieve the most accurate measurements. Ideally, the calibration ball should be placed at the same vertical height as the object to be measured; however, if this cannot be achieved, the magnification error can be expected to be approximately 1% per centimeter of distance.     

Paratuberculosis in a mandrill (Papio sphinx).

A 2.5-year-old captive female mandrill (Papio sphinx) died following a protracted course of intermittent abdominal bloat, diarrhea, and severe weight loss. Necropsy revealed emaciation and marked gastrointestinal distention with gas and ingesta. Histologic evaluation revealed severe diffuse granulomatous enterocolitis and mesenteric lymphadenitis with massive numbers of 1-2-microm acid-fast bacilli within macrophages. Additionally, there was moderate to severe multifocal myocardial and vascular amyloidosis, moderate multifocal pyogranulomatous interstitial pneumonia with no acid-fast bacteria, and moderate multifocal glossal candidiasis. Samples of feces, ileum, and colon were positive for Mycobacterium avium subsp. paratuberculosis by radiometric culture and a polymerase chain reaction-amplified DNA probe specific for the insertion sequence IS900 of this organism.     

The effect of rehabilitation of northern elephant seals (Mirounga angustirostris) on antimicrobial resistance of commensal Escherichia coli

The aim of this study was to determine if antimicrobial drug use increases resistance of commensal gastrointensinal Escherichia coli of wild northern elephant seals (Mirounga angustirostris) treated in rehabilitation, and, if so, identify the risk factors involved. Minimum inhibitory concentration (MIC) levels of twelve antimicrobial drugs were determined for 289 E. coli isolates from 99 seals sampled at admission and 277 isolates obtained at release from rehabilitation using broth microdilution. Prevalence of E. coli antimicrobial resistance, MIC(50), MIC(90), and clustering of MIC values were determined for seals and the data were analyzed using Fisher's exact test, ordinal logistic regression and negative binomial regression. At release from rehabilitation 77.8% of the seals had antimicrobial resistant E. coli compared to 38.4% of the seals at admission. The MIC(90) for amoxicillin-clavulanic acid, chloramphenicol, enrofloxacin, ticarcillin-clavulanic acid, and trimethoprim-saulfamethoxazole were at levels considered to be sensitive at admission but they increased to levels of resistance at release. E. coli were grouped into four clusters by their MIC values, with increasing levels of resistance going from Cluster 1 to 4. A primary risk factor associated with the probability of a seal having E. coli in Clusters 3 and 4 was time in rehabilitation, regardless of whether the animal received treatment with antimicrobial drugs, suggesting nosocomial infection. The results of this study provide evidence that increased levels of hygiene and appropriate use of antimicrobial therapy might be important in the rehabilitation of wild animals to prevent rise in the prevalence of antimicrobial resistant bacteria.     

Continuous low-dose oral chemotherapy for adjuvant therapy of splenic hemangiosarcoma in dogs

BACKGROUND: Hemangiosarcoma (HSA) is a highly metastatic and often rapidly fatal tumor in dogs. At present, conventional adjuvant chemotherapy provides only a modest survival benefit for treated dogs. Continuous oral administration of low-dose chemotherapy (LDC) has been suggested as an alternative to conventional chemotherapy protocols. Therefore, we evaluated the safety and effectiveness of LDC using a combination of cyclophosphamide, etoposide, and piroxicam as adjuvant therapy for dogs with stage II HSA. HYPOTHESIS: We hypothesized that oral adjuvant therapy with LDC could be safely administered to dogs with HSA and that survival times would be comparable to those attained with conventional doxorubicin (DOX) chemotherapy. ANIMALS: Nine dogs with stage II splenic HSA were enrolled in the LDC study. Treatment outcomes were also evaluated retrospectively for 24 dogs with stage II splenic HSA treated with DOX chemotherapy. METHODS: Nine dogs with stage II splenic HSA were treated with LDC over a 6-month period. Adverse effects and treatment outcomes were determined. The pharmacokinetics of orally administered etoposide were determined in 3 dogs. Overall survival times and disease-free intervals were compared between the 9 LDC-treated dogs and 24 DOX-treated dogs. RESULTS: Dogs treated with LDC did not develop severe adverse effects, and long-term treatment over 6 months was well-tolerated. Oral administration of etoposide resulted in detectable plasma concentrations that peaked between 30 and 60 minutes after dosing. Both the median overall survival time and the median disease-free interval in dogs treated with LDC were 178 days. By comparison, the overall survival time and disease-free interval in dogs treated with DOX were 133 and 126 days, respectively. CONCLUSIONS: Continuous orally administered LDC may be an effective alternative to conventional high-dose chemotherapy for adjuvant therapy of dogs with HSA.     

Preliminary studies on the effectiveness of the novel pulicide, spinosad, for the treatment and control of fleas on dogs

Spinosad is a novel mode-of-action insecticide produced from a family of natural products derived from fermentation of the actinomycete, Saccharopolyspora spinosa. Separate studies were undertaken to determine the minimum effective dose of spinosad given orally for the treatment of experimentally induced flea infestations (Ctenocephalides felis) on dogs, and to assess any potential impacts of feeding canned or dry food at the time of dosing. Both were randomized block (blocked by gender and pre-treatment flea counts), blinded parallel-arm studies, with dogs selected on health and ability to maintain pre-treatment flea populations. For dose selection, 48 dogs were allocated among six groups (8 dogs/group; 4 males, 4 females): placebo-treated negative control, spinosad in gelatin capsules at 15, 20, 30 and 40 mg/kg administered per os; and topical imidacloprid (10 mg/kg) as a positive control. Placebo and spinosad treatments were administered on Days 0, 30 and 60, imidacloprid only on Day 0. In a second study to assess the impact of food type at the time of dosing, three groups were formed: placebo-treated control (8 dogs; 4 males, 4 females), spinosad (30 mg/kg) administered with canned food (8 male dogs, 8 females); and spinosad (30 mg/kg) with dry food (8 males, 8 females). Treatments were administered on Days 0 and 30. To assess post-treatment persistent efficacy, flea infestations were repeated at regular post-treatment intervals, beginning on Day 5 through Day 89 in the dose selection study and Day 58 in the impact of food type and dosing study. Flea counts were performed 48 h post-infestation by study personnel who were blinded to treatments. In the dose selection study, compared to geometric mean live flea counts in the control group, each spinosad dose was highly effective (99.8–100%) at 7, 14 and 21 days after treatment. Only the 30 and 40 mg/kg doses maintained high efficacy (97.2–100%) until 30 days after treatment, with no difference between the two. Imidacloprid was highly effective at Day 30, with significant difference only from the 15 mg/kg spinosad group. Because there was no significant difference between the higher spinosad rates, 30 mg/kg was selected as the optimal minimum effective dose. In the second study, spinosad was highly effective at all post-treatment flea counts (98–100%). Taken together, these studies demonstrate that repeated monthly oral treatments with spinosad at 30 mg/kg provide sustained control of C. felis on dogs. There were no treatment-related adverse events in either study, indicating that spinosad has potential to be used monthly as a safe and effective flea adulticide, providing sustained activity that matches that of currently used topical products.