A predator unmasked: life cycle of Bdellovibrio bacteriovorus from a genomic perspective

Predatory bacteria remain molecularly enigmatic, despite their presence in many microbial communities. Here we report the complete genome of Bdellovibrio bacteriovorus HD100, a predatory Gram-negative bacterium that invades and consumes other Gram-negative bacteria. Its surprisingly large genome shows no evidence of recent gene transfer from its prey. A plethora of paralogous gene families coding for enzymes, such as hydrolases and transporters, are used throughout the life cycle of B. bacteriovorus for prey entry, prey killing, and the uptake of complex molecules.     

Comment on "Nonreciprocal light propagation in a silicon photonic circuit"

We show that the structure demonstrated by Feng et al. (Reports, 5 August 2011, p. 729) cannot enable optical isolation because it possesses a symmetric scattering matrix. Moreover, one cannot construct an optical isolator by incorporating this structure into any system as long as the system is linear and time-independent and is described by materials with a scalar dielectric function.     

Anaplasma phagocytophilum in horses and ticks: a preliminary survey of Central Italy

Anaplasma phagocytophilum, the causative agent of granulocytic ehrlichiosis, affects several species of wild and domesticated mammals, including horses. In this work we compared direct and indirect methods to evaluate A. phagocytophilum presence in Central Italy: 135 sera were screened by IFA for A. phagocytophilum and other haemopathogens (Theileria equi and Babesia caballi). Each horse was also tested for A. phagocytophilum 16S rRNA with a nested-PCR technique. In order to examine the risk of A. phagocytophilum transmission, 114 ticks were examined for the presence of A. phagocytophilum by PCR targeting the 16S rRNA. The seroprevalence against A. phagocytophilum was 17.03% and 11 horses (8.14%) showed positive PCR results. The concordance rate of A. phagocytophilum detection between IFAT and PCR had a K value of 0.34.     

Stability in reproductive timing and habitat usage of Chinook salmon across six years of varying environmental conditions and abundance

The spatial and temporal distribution of spawning activity by autumn‐run Chinook salmon Oncorhynchus tshawytscha (Walbaum) was examined across multiple years. The study period included two years of extreme drought conditions when water temperatures in the spawning reach of the Stanislaus River were considered sub‐optimal for spawning and egg incubation. Despite varying levels of superimposition, redd counts and densities remained stable and positively associated with river location, indicating that superimposition may be driven by habitat preference rather than the absence of suitable spawning locations. Spawning occurred slightly later during drought years (6–10 days later compared with wetter years). This delay was attributable to deferred migration instead of deferred spawning, and the majority of redds were constructed at water temperatures exceeding the optimal temperature range. As a consequence, estimates of juvenile production during 2014 and 2015 were among the lowest on record. These findings may be related in part to the high hatchery contribution to the population, above‐average temperatures during spawning and incubation, and superimposition rates. Management recommendations include adequate cold‐water storage in the upstream reservoir, refined spawning habitat restoration techniques in the light of superimposition rates and, on a broader system scale, actions that reduce the amount of stray hatchery Chinook salmon.     

Assessment of defined antigens for the diagnosis of bovine tuberculosis in skin test-reactor cattle

The continued use of purified protein derivative (PPD) tuberculin is considered to be the main factor which limits the specificity of diagnostic tests for bovine tuberculosis (TB). This study evaluated a whole blood interferon-gamma (IFN-gamma) assay and compared the diagnostic potential of PPD with two tuberculosis-specific antigens, ESAT-6 and MPB70. To provide estimates of sensitivity and specificity, responses were measured in 180 skin test-reacting cattle, of which 131 were confirmed as tuberculous, and in 128 cattle from TB-free herds. For the skin test reactors, there was a positive correlation between the IFN-gamma responses to PPD from Mycobacterium bovis (PPDB) and PPD from Mycobacterium avium (PPDA), indicating cross-reactivity between these complex antigens which are the basis of the skin test. In comparisons of the ESAT-6 IFN-gamma test with a PPD IFN-gamma test (using PPDB compared with PPDA), there was a decrease in sensitivity (76.3 per cent vs 89.3 per cent), but a clear increase in specificity (99.2 per cent vs 92.2 per cent). The provision of high specificity, even with lower sensitivity, offers major benefits for testing in areas with a low incidence of TB.     

Evaluation of serum values of pancreatic enzymes after endoscopic retrograde pancreatography in dogs

OBJECTIVE: To assess the safety of endoscopic retrograde pancreatography (ERP) in dogs by performing repeated clinical examinations and laboratory analyses of serum amylase, lipase, canine trypsin-like immunoreactivity (cTLI), and canine pancreatic elastase 1 (cE1) after the procedure. ANIMALS: 7 healthy Beagles. PROCEDURES: Clinical examinations were performed and blood samples obtained for serum enzyme determinations before and at intervals (10 minutes; 2, 4, and 6 hours; and 1, 2, and 3 days) after ERP. RESULTS: Repeated clinical examinations revealed no signs of ERP-induced complications in the 7 dogs. Results of repeated laboratory tests indicated a transient increase in serum values of amylase, lipase, and cTLI but not cE1. Mean +/- SD lipase activity increased from 120.7 +/- 116.4 U/L to 423.4 +/- 243.1 U/L at 4 hours after ERP. Median serum cTLI concentration increased from 16.2 microg/L (range, 77 to 26.5 microg/L) to 34.9 microg/L (range, 16.6 to 68.3 microg/L) 10 minutes after ERP. Enzyme values returned to baseline levels at the latest on day 2 in 6 of 7 dogs. Highest values for serum amylase, lipase, and cTLI and their delayed return to baseline values were detected in 1 dog with contrast filling of the pancreatic parenchyma. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ERP appears to be a safe imaging technique of pancreatic ducts in healthy dogs, although it induced a transient increase in serum values of pancreatic enzymes. In dogs, repeated clinical examinations and serum enzyme determinations can be used to monitor ERP-induced complications such as acute pancreatitis.     

Use of nootkatone as a senescence indicator for Rouge La Toma Cv. grapefruit (Citrus paradisi Macf.)

The objective of this research was to study the usefulness of nootkatone as a senescence indicator for Rouge La Toma cv. grapefruit (Citrus paradisi Macf.), simulating different treatments that included the normal postharvest handling of citrus fruits: temperature conditioning, cold storage, shipment periods to overseas markets such as Japan and the U.S., marketing conditions, and storage at nonchilling temperature (control treatments). The highest nootkatone levels, determined by GLC-MS analyses, were detected in fruits subjected to control treatments. No significant differences were observed in nootkatone levels between treatments either with or without temperature conditioning prior to the start of the cold storage. Levels of nootkatone increased throughout time for all assayed treatments. The linear regressions of nootkatone levels showed correlation coefficients of 0.80 and 0.83 with storage time (29 and 42 days, respectively). Therefore, nootkatone appears to be a good indicator of senescence for Rouge La Toma grapefruit.