Gallbladder microbiota in healthy dogs and dogs with mucocele formation

To date studies have not investigated the culture-independent microbiome of bile from dogs, a species where aseptic collection of bile under ultrasound guidance is somewhat routine. Despite frequent collection of bile for culture-based diagnosis of bacterial cholecystitis, it is unknown whether bile from healthy dogs harbors uncultivable bacteria or a core microbiota. The answer to this question is critical to understanding the pathogenesis of biliary infection and as a baseline to exploration of other biliary diseases in dogs where uncultivable bacteria could play a pathogenic role. A pressing example of such a disease would be gallbladder mucocele formation in dogs. This prevalent and deadly condition is characterized by excessive secretion of abnormal mucus by the gallbladder epithelium that can eventually lead to rupture of the gallbladder or obstruction of bile flow. The cause of mucocele formation is unknown as is whether uncultivable, and therefore unrecognized, bacteria play any systematic role in pathogenesis. In this study we applied next-generation 16S rRNA gene sequencing to identify the culture-negative bacterial community of gallbladder bile from healthy dogs and gallbladder mucus from dogs with mucocele formation. Integral to our study was the use of 2 separate DNA isolations on each sample using different extraction methods and sequencing of negative control samples enabling recognition and curation of contaminating sequences. Microbiota findings were validated by simultaneous culture-based identification, cytological examination of bile, and fluorescence in-situ hybridization (FISH) performed on gallbladder mucosa. Using culture-dependent, cytological, FISH, and 16S rRNA sequencing approaches, results of our study do not support existence of a core microbiome in the bile of healthy dogs or gallbladder mucus from dogs with mucocele formation. Our findings further document how contaminating sequences can significantly contribute to the results of sequencing analysis when performed on samples with low bacterial biomass

Lagging Response of Belowground Functional Traits to Environmental Cues in a Mature Amazonian Tropical Rainforest

Context/Purpose: The stress-dominance hypothesis (SDH) is a model of community assembly predicting that the relative importance of environmental filtering increases and competition decreases along a gradient of increasing environmental stress. Therefore, trait variation at the community level should increase as resources are more available. Although the SDH was designed to explain spatial changes in plant communities based on aboveground traits, it is possible that root communities show similar switches in strategies at temporal scales in response to pulses in resource availability. Methods: To test this hypothesis we sampled for two years the morphological changes in root systems in a mature tropical forest in Central Amazon. Thirty-six samples along a 500 m transect were taken each three months from February 2016 to February 2018, separating the uppermost organic layer (0-5 cm) from the mineral soil (5-15 cm). Besides root biomass, we scanned approximately 20% of the total root systems to calculate specific root length (SRL), average diameter (D), root tissue density (RTD), and branching index (BI). Spatially, we expected shifts from acquisitive to conservative syndromes as roots penetrate in the mineral soil. Temporarily, we hypothesized that traits associated with resource acquisition (SRL, SRTA, BI) will increase with soil moisture. Moreover, we expected that trait range will increase as resources become more available. Results: We found significant differences in biomass and morphological traits between the organic and mineral soils. We found no patterns between biomass increases in seasonality, but mean community traits change significantly with seasonal rain patterns. More interestingly, changes in mean and range values were more strongly associated with rain events three months before the collecting date, suggesting a lagging between rain events and belowground community responses. Conclusions: Belowground dynamics are structured spatially and temporarily in tropical forests, in synchrony with the availability of resources, as predicted by the SHD. Our results suggest that species tend to show similar traits during stressful times but diverge during acquisition periods. The results suggest a belowground dimension to niche segregation little explored in tropical biomes to date

Fast-timing measurements in neutron-rich odd-mass zirconium isotopes using LaBr3:Ce detectors coupled with Gammasphere

A fast-timing experiment was performed at the Argonne National Laboratory to measure the lifetimes of the lowest lying states of nuclei belonging to the deformed regions around mass number A 110 and A 150. These regions were populated via spontaneous fission of 252 Cf and the gamma radiation following the decay of excited states in the fission fragments was measured using 51 Gammasphere detectors coupled with 25 LaBr 3 :Ce detectors. A brief description of the acquisition system and some preliminary results from the fast-timing analysis of the fission fragment 100Zr are presented. The lifetime value of \u3c4 = 840(65) ps was found for the 2 + state in 100 Zr consistent within one standard deviation of the adopted value with 791 +26 -35 ps. This is associated with a quadrupole deformation parameter of 0.36(2) which is within one standard deviation of the literature value of 0.3556 +82 -57

Fast-timing measurements in the ground-state band of Pd114

Using a hybrid Gammasphere array coupled to 25 LaBr3(Ce) detectors, the lifetimes of the first three levels of the yrast band in Pd-114, populated via Cf-252 decay, have been measured. The measured lifetimes are tau(2+) = 103(10) ps, tau(4+) = 22(13) ps, and tau(6+) <= 10 ps for the 2(1)(+), 4(1)(+), and 6(1)(+) levels, respectively. Palladium-114 was predicted to be the most deformed isotope of its isotopic chain, and spectroscopic studies have suggested it might also be a candidate nucleus for low-spin stable triaxiality. From the lifetimes measured in this work, reduced transition probabilities B(E2; J -> J - 2) are calculated and compared with interacting boson model, projected shell model, and collective model calculations from the literature. The experimental ratio R-B(E2) = B(E2; 4(1)(+) -> 2(1)(+))/B(E2; 2(1)(+) -> 0(1)(+)) = 0.80(42) is measured for the first time in Pd-114 and compared with the known values R-B(E2) in the palladium isotopic chain: the systematics suggest that, for N = 68, a transition from gamma-unstable to a more rigid gamma-deformed nuclear shape occurs

Quadrupole moment measurements for strongly deformed bands in Hf171,172

A lifetime experiment, using the Doppler-shift attenuation method, has been performed at Gammasphere to measure the transition quadrupole moments Q t of strongly deformed bands in Hf171 and Hf172. The measured value of Qt ~ 9.5 e b for the band labeled ED in Hf171 strongly supports the recent suggestion that this sequence and several structures with similar properties in neighboring Hf isotopes are associated with a near-prolate shape with a deformation enhanced relative to that of normal deformed structures. The measured values of Qt- 14 e b for the bands labeled SD1 and SD3 in Hf172 confirm that these sequences are associated with a prolate superdeformed shape, a property inferred in earlier work from other measured characteristics of the bands. Similar bands in Hf173-175 are also likely to be associated with superdeformed shapes. The observations are in contrast to predictions of cranking calculations performed with the ultimate cranker code

High-spin proton alignments and evidence for a second band with enhanced deformation in 171Hf

High-spin properties of the nucleus 171Hf were studied through the 128Te(48Ca,5n) reaction. Previously known bands have been extended to significantly higher spins and four new bands have been extracted from these data. The results are discussed within the framework of the cranked shell model aided by a comparison with level structures in the neighboring nuclei. The band crossings at rotational frequencies ∼500 keV are interpreted as caused by the alignments of h11/2 and h9/2 proton orbitals. Band ED2 exhibits an alignment pattern similar to that of band ED1 which was reported in a recent paper and proposed to be built on a second potential energy minimum involving the deformation-driving proton i13/2 - h9/2 configuration. It is likely that band ED2 is also associated with a deformation enhanced with respect to that of the normal deformed structures. Further experimental investigation is needed to ascertain the nature of this band

Fine roots stimulate nutrient release during early stages of leaf litter decomposition in a Central Amazon rainforest

Purpose Large parts of the Amazon rainforest grow on weathered soils depleted in phosphorus and rock-derived cations. We tested the hypothesis that in this ecosystem, fine roots stimulate decomposition and nutrient release from leaf litter biochemically by releasing enzymes, and by exuding labile carbon stimulating microbial decomposers. Methods We monitored leaf litter decomposition in a Central Amazon tropical rainforest, where fine roots were either present or excluded, over 188 days and added labile carbon substrates (glucose and citric acid) in a fully factorial design. We tracked litter mass loss, remaining carbon, nitrogen, phosphorus and cation concentrations, extracellular enzyme activity and microbial carbon and nutrient concentrations. Results Fine root presence did not affect litter mass loss but significantly increased the loss of phosphorus and cations from leaf litter. In the presence of fine roots, acid phosphatase activity was 43.2% higher, while neither microbial stoichiometry, nor extracellular enzyme activities targeting carbon- and nitrogen-containing compounds changed. Glucose additions increased phosphorus loss from litter when fine roots were present, and enhanced phosphatase activity in root exclusions. Citric acid additions reduced litter mass loss, microbial biomass nitrogen and phosphorus, regardless of fine root presence or exclusion. Conclusions We conclude that plant roots release significant amounts of acid phosphatases into the litter layer and mobilize phosphorus without affecting litter mass loss. Our results further indicate that added labile carbon inputs (i.e. glucose) can stimulate acid phosphatase production by microbial decomposers, highlighting the potential importance of plant-microbial feedbacks in tropical forest ecosystems

Nuclear shapes of highly deformed bands in Hf171,172 and neighboring Hf isotopes

A Gammasphere experiment was carried out to search for triaxial strongly deformed (TSD) structures in Hf171,172 and the wobbling mode, a unique signature of nuclei with stable triaxiality. Three strongly deformed bands in Hf172 and one in Hf171 were identified through Ca48(Te128, xn) reactions. Linking transitions were established for the band in Hf171 and, consequently, its excitation energies and spins (up to 111/2) were firmly established. However, none of the Hf172 sequences were linked to known structures. Experimental evidence of triaxiality was not observed in these bands. The new bands are compared with other known strongly deformed bands in neighboring Hf isotopes. Theoretical investigations within various models have been performed. Cranking calculations with the Ultimate Cranker code suggest that the band in Hf171 and two previously proposed TSD candidates in Hf170 and Hf175 are built on proton (i13/2h9/2) configurations, associated with near-prolate shapes and deformations enhanced with respect to the normal deformed bands. Cranked relativistic mean-field calculations suggest that band 2 in Hf175 has most likely a near-prolate superdeformed shape involving the πi13/2νj15/2 high-j intruder orbitals. It is quite likely that the bands in Hf172 are similar in character to this band

K-hindered decay of a six-quasiparticle isomer in Hf176

The structure and decay properties of high-K isomers in Hf176 have been studied using beam sweeping techniques and the Gammasphere multidetector array. A new ΔK=8 decay branch, from a Kπ=22⊃-, six-quasiparticle, isomeric (t1/2=43μs) state at 4864 keV to the 20⊃- state of a Kπ=14⊃- band, has been identified. The reduced hindrance factor per degree of K forbiddenness for this decay is measured to be unusually low (fν=3.2), which suggests K mixing in the states involved. The deduced interaction matrix elements are discussed within the context of relevant K-mixing scenarios. The 3266-keV state, previously interpreted as a Kπ=16⊃+ intrinsic state, is reassigned as the Jπ=16⊃+ member of the band based on the Kπ=15⊃+ state at 3080 keV. The systematics of fν values as a function of the degree of forbiddenness is discussed in light of this change

Perspectives in visual imaging for marine biology and ecology: from acquisition to understanding

Durden J, Schoening T, Althaus F, et al. Perspectives in Visual Imaging for Marine Biology and Ecology: From Acquisition to Understanding. In: Hughes RN, Hughes DJ, Smith IP, Dale AC, eds. Oceanography and Marine Biology: An Annual Review. 54. Boca Raton: CRC Press; 2016: 1-72