Limited native plant regeneration in novel, exotic-dominated forests on Hawai’i

Ecological invasions are a major driver of global environmental change. When invasions are frequent and prolonged, exotic species can become dominant and ultimately create novel ecosystem types. These ecosystems are now widespread globally. Recent evidence from Puerto Rico suggests that exotic-dominated forests can provide suitable regeneration sites for native species and promote native species abundance, but this pattern has been little explored elsewhere. We surveyed 46 sites in Hawai’i to determine whether native species occurred in the understories of exotic-dominated forests. Native trees smaller than 10 cm in diameter were absent in 28 of the 46 sites and rare in the others. Natives were never the dominant understory species; in fact, they accounted for less than 10% of understory basal area at all but six sites, and less than 4% on average. Sites with native species in the understory tended to be on young lava substrate lacking human disturbance, and were mostly located close to intact, native-dominated forest stands. Even where we found some native species, however, most were survivors of past exotic encroachment into native forest, rather than products of active recolonization by native species. In contrast with successional trajectories in Puerto Rico, Hawaii's exotic-dominated forests can emerge, via invasion, without human disturbance and native Hawaiian plants are largely unable to colonize them once they appear. We suggest that a wide diversity of growth strategies among the exotic species on Hawai’i may limit the opportunities for native plants to colonize exotic-dominated forests.     

Redwood/tanoak stand development and response to tanoak mortality caused by Phytophthora ramorum

Coast redwood (Sequoia sempervirens) and tanoak (Lithocarpus densiflorus) form mixed-evergreen forests along the northern California coast. In the mid-1990s, an introduced pathogen (Phytophthora ramorum) began causing extensive mortality of tanoak in these forests. This research reconstructed stand development patterns occurring in stands with and without the pathogen, measured stand responses to tanoak mortality, and developed projections of future stand development and structure in the presence of P. ramorum. Redwood forms an upper canopy layer while tanoak forms a multicohort lower canopy, resulting in distinct vertical stratification patterns. Individual redwood tree response patterns to tanoak mortality included crown expansion, increased basal sprouting, and increased basal area growth. Future stand structures will likely have greater proportions of redwood relative to tanoak.     

Full recovery after cardiac arrest secondary to accidental iatrogenic venous air embolism in a cat

Objective – To describe the successful management of cardiac arrest following accidental venous air embolism (VAE) in a cat. Case Summary – A 3‐year‐old spayed female domestic shorthair cat, weighing 4 kg, was presented for continuation of its chemotherapy protocol. The cat was inadvertently administered approximately 5.5 mL of air IV during initiation of fluid therapy. Immediate cardiac arrest resulted and CPR successfully achieved return of spontaneous circulation. The cat was discharged 5 days later and is reportedly clinically normal 7 months post‐discharge. New or Unique Information Provided – VAE has been rarely reported in the veterinary literature. This is the first report of a cat surviving cardiac arrest secondary to VAE.     

Smoke-derived taint in wine: the release of smoke-derived volatile phenols during fermentation of Merlot juice following grapevine exposure to smoke

The release of smoke-derived volatile phenols during the fermentation of Merlot grapes, following grapevine exposure to smoke, has been investigated. The concentrations of guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, and eugenol were determined by gas chromatography-mass spectrometry and found to increase throughout the winemaking process. Only trace levels (< or = 1 microg/L) of guaiacol and 4-methylguaiacol could be detected in free run juice derived from the fruit of smoked vines; the highest levels, 388 microg/L and 93 microg/L, respectively, were observed in the finished wine. Control wine (derived from fruit of unsmoked vines) contained 4 microg/L guaiacol, with the volatile phenols either not detected or detected at only trace levels (< or = 1 microg/L) throughout fermentation. The role of enzyme and acid catalyzed hydrolysis reactions in releasing smoke-derived volatile compounds was also investigated. The volatile phenols were released from smoked free run juice by strong acid hydrolysis (pH 1.0) and enzyme (beta-glucosidase) hydrolysis, but not mild acid hydrolysis (juice pH 3.2-3.7). Guaiacol was again the most abundant smoke-derived phenol, present at 431 microg/L and 325 microg/L in strong acid and enzyme hydrolysates, respectively. Only trace levels of each phenol could be detected in each control hydrolysate. This study demonstrates the potential for under-estimation of smoke taint in fruit and juice samples; the implications for the assessment of smoke taint and quantification of volatile phenols are discussed.     

The problem of gastric atony

Normal gastrointestinal motility is crucial for maintaining an appropriate balance of microorganisms within the gut. Disruption of this system results in bacterial overgrowth and associated complications such as bacterial translocation, aspiration pneumonia, and sepsis. Critically ill animals are at increased risk of developing gastroparesis caused by primary gastrointestinal disturbances or severe metabolic derangements that impact gastrointestinal function. In the intensive-care setting, delayed gastric emptying complicates enteral nutrition, and the catabolic effects of severe illness further deplete the patient's caloric reserves, resulting in impaired wound healing, decreased immune function, and increased morbidity and mortality. The use of promotility drugs in critically ill patients is a safe, effective means to circumvent the problem of gastric atony and improve patient recovery. Understanding the drugs available and their interaction with the receptors involved in neuromuscular transmission within the gastrointestinal tract will aid the clinician in selecting the optimal prokinetic therapy.     

Fatal yersiniosis in farmed deer caused by Yersinia pseudotuberculosis serotype O:3 encoding a mannosyltransferase-like protein WbyK.

Sudden death of 9 deer occurred in a large enclosed deer farm with approximately 400 heads of cervids. Fatal yersiniosis was diagnosed in 2 deer that were submitted for laboratory diagnosis. Histopathologically, the disease was characterized by multifocal pulmonary hemorrhage and mild interstitial pneumonia, marked diffuse cholangiohepatitis, minimal myocarditis with mild myocardial degeneration, and mild multifocal suppurative cystic colitis. Yersinia pseudotuberculosis was isolated from the lungs and colon of the affected animals. The isolates were PCR-positive for genes virF, inv, yopB, and yopH, which are essential for invasion and colonization of host intestine and lung. The isolates reacted with polyclonal antibodies against serotype O:3 antigen. The O-genotyping patterns of the isolates were identical with each other, but different from those of the 21 O-genotypes (or serotypes) reported previously. In addition to the O-antigen genes possessed by classical serotype O:3, a gene (wbyK) encoding a mannosyltransferase-like protein was detected in these isolates. The wbyK gene of the isolates showed 94% of DNA sequence homology with the wbyK gene harbored by Y. pseudotuberculosis O:1b. On the basis of pathology, bacteriology, and serology, the authors concluded that the acute deaths of these deer were caused by Y. pseudotuberculosis infection. Molecular characterization of the isolate revealed a genetic heterogeneity in the O-antigen gene cluster of Y. pseudotuberculosis serotype O:3.     

Nitrogen and water use efficiency of zucchini squash for a plastic mulch bed system on a sandy soil

Zucchini squash (Cucurbita pepo L.) is an economically important vegetable crop in Florida. Typically, it is intensively managed with high inputs of fertiliser and irrigation water. Our objectives were to evaluate the interaction between fertilisation rates and irrigation treatments, and to quantify nitrate leaching in a plastic mulched/drip irrigated zucchini squash production systems. Three studies were carried out. The first study evaluated different depth placement of drip and fertigation lines on plant growth and fruit yield. Treatments included SUR (both irrigation and fertigation drip lines placed on the surface); S&S (both lines buried 0.15 m deep); and SDI (irrigation line placed 0.15 m below the fertigation line on the surface). The second and third studies compared three different N-rates and different soil moisture sensor-based irrigation strategies. Nitrate-N leaching was monitored by zero tension drainage lysimeters and soil samples. N leaching increased when irrigation and N-rates increased, with values ranging from 2 to 45 kg ha⁻¹ of N. Use of SDI increased yields by 16% compared to the S&S treatment, and reduced nitrate leaching by 93% while increasing the water use efficiency by 75% compared to a fixed 2-h irrigation event per day treatment. Application of N above the standard recommended rate of 145 kg ha⁻¹ did not increase yield, although yields were reduced at the lowest N-rate. The use of soil moisture sensors for automatic irrigation control reduced irrigation application and minimized nitrogen leaching. In addition, combining the soil moisture controlled SDI system that had surface applied fertigation resulted in similar or higher yields, while reducing both water use and potential N leaching because of improved nutrient retention in the root zone.     

OUTCOMES AND PROGNOSTIC FACTORS ASSOCIATED WITH CANINE SINONASAL TUMORS TREATED WITH CURATIVE INTENT CONE‐BASED STEREOTACTIC RADIOSURGERY (1999–2013)

Stereotactic radiosurgery (SRS) is a relatively new therapeutic option in veterinary oncology. The role of this modality has not been extensively evaluated for the use in canine nasal tumors. The objective of this retrospective, observational study was to describe the clinical outcome and prognostic factors associated with survival times in a sample of canine patients treated with SRS for sinonasal tumors. Fifty‐seven dogs with sinonasal tumors met inclusion criteria. Histologic diagnoses included sarcoma (SA) (n = 9), carcinoma (CA) (n = 40), osteosarcoma (OSA) (n = 7), and round cell (n = 1). Four of 57 cases were treated twice with SRS. For these, the median and mean doses delivered were 30Gy and 33Gy, respectively (range 18.75Gy–56Gy). Late effects occurred in 23 cases and ranged from grades I–III. The median overall survival time was 8.5 months. The median overall survival times in dogs with tumor type of CA, SA, and OSA were 10.4, 10.7, and 3.1 months, respectively. Dogs with the tumor type of OSA had shorter overall survival time than that in dogs with tumor type of CA and SA. Findings from this retrospective study indicated that SRS may be beneficial for canine patients with sinonasal tumors, however a controlled clinical trial would be needed to confirm this. Prospective studies are also needed to better define the role of SRS as palliative or curative, and to further investigate the risk of clinically significant toxicity.