Intermediate sucrose octa-acetate sensitivity suggests a third allele at mouse bitter taste locus Soa and Soa-Rua identity

Mice have been characterized as either tasters or non-tastersof the bitter compound sucrose octa-acetate(SOA). However, 11of 17 supposedly non-taster inbred strains were found to avoid1 mM SOA. All 17 strains were indifferent to 0.1 mM SOA. Tasterstrains avoided both concentrations. The intermediate phenotypewas dubbed demitaster. A consistent phenotypic dominance orderwas found in crosses among both inbred and outbred strains (taster> non-taster > demitaster). Demitasters were found (withtasters) in an outbred strain showing monogenic segregationfor SOA avoidance. This, plus monogenic segregation in a back-crossof taster to demitaster inbred strains, suggested a third alleleat the Soa locus (Soa^c). Demitaster allelism was supported bythe strong associations found in 15 strains between the threeSOA phenotypes and HindIII restriction fragment patterns forthe closely linked Prp (proline rich protein) loci. SOA demitasterstrains were also intermediate in raffinose undeca-acetate (RUA)avoidance. Furthermore, B6.SW-Soa² congenic mice avoided notonly SOA, but RUA and eight other acetylated sugars. A previouslyproposed separate RUA-sensitivity gene (Rua) thus appeared tobe redundant.     

Teichoicase from Bacillus subtilis Marburg.

The properties of a teichoic acid degrading enzyme (teichoicase) isolated from Bacillus subtilis Marburg are described. The purified enzyme showed phosphodiesterase activity but not phosphomonoesterase activity, and it had an absolute substrate specificity for alpha-glucosylated glycerol teichoic acid, the endogenous cell wall teichoic acid of the enzyme-producing cell. The substrate was degraded by an exo-mechanism yielding the monomer alpha-D-glucose 1 leads to 2 (sn)glycero-3-phosphate. When B. subtilis Marburg was grown in a rich medium, enzyme activity was detected in extracts from sporulating cells. Teichoicase activity was present in a mutant blocked in stage II of the sporulation process but was absent in a mutant blocked in stage O. It was concluded that teichoicase is active on enzyme-producing cells since the reaction product could be detected in their culture supernatant. Attempts to demonstrate analogous enzyme activity in other Bacillus strains failed. The enzyme could be used for the rapid detection of alpha-glucosylated glycerol teichoic acid and for the controlled alteration of native bacterial cell surfaces exhibiting the appropriate structure.     

Pelagic denitrification and methane oxidation in oxygen-depleted waters of the Louisiana shelf

Anthropogenic nutrient inputs fuel eutrophication and hypoxia ([O₂]?<?2 mg L^?1), threatening coastal and near shore environments across the globe. The world’s second largest anthropogenic coastal hypoxic zone occurs annually along the Louisiana (LA) shelf. Springtime loading of dissolved inorganic nitrogen (DIN) from the Mississippi River, combined with summertime stratification and increased water residence time on the shelf, promotes establishment of an extensive hypoxic zone that persists throughout the summer. We investigated the patterns of pelagic denitrification and methane (CH₄) oxidation along the LA shelf. Microbial activity rates were determined along with concentrations of dissolved nutrients and greenhouse gases, nitrous oxide (N₂O) and CH₄, during summer in 2013, 2015, and 2016. We documented denitrification rates up to 1900 nmol N L^?1 d^?1 and CH₄ oxidation rates as high as 192 nmol L^?1 d^?1 in hypoxic waters characterized by high concentrations of N₂O (range: 1 to 102 nM) and CH₄ (range: 3 to 641 nM). Ecosystem scaling estimates suggest that pelagic denitrification could remove between 0.1 and 47% of the DIN input from the Mississippi River, whereas CH₄ oxidation does not function as an effective removal process with CH₄ escaping to the atmosphere. Denitrification and CH₄ oxidizing bacteria within the LA shelf hypoxic zone were largely unable to keep up with the DIN and CH₄ inputs to the water column. Rates were variable and physiochemical dynamics appeared to regulate the microbial removal capacity for both nitrate/nitrite and CH₄ in this ecosystem.

     

Restoration approach influences carbon exchange at in-situ oil sands exploration sites in east-central Alberta

Wetlands Ecology and Management - Oil sands exploration activities across the Alberta boreal peatlands requires tree clearing and results in sites being left compressed and with altered understory...     

The Use of Vacuum Erection Devices in Erectile Dysfunction After Radical Prostatectomy

The risk of postoperative erectile dysfunction (ED) following radical prostatectomy (RP) is reported to be between 14% and 89%. With an increase in the detection of prostate cancer in younger men, there is a greater emphasis on the appropriate management of ED following RP. A number of options are available to manage ED after RP, including phosphodiesterase-5 inhibitors, intracorporeal injections, intraurethral alprostadil, and vacuum erection devices (VEDs). Penile rehabilitation programs are increasingly used to facilitate the return of natural postoperative erections; the VED is an ideal therapy given that it increases blood flow and oxygenation to the corpora to reverse the changes that result in ED after RP.Key words: Erectile dysfunction, Radical prostatectomy, Vacuum erection device, Penile rehabilitationProstate cancer is the most common cancer in men over the age of 50 years.¹ When patients undergo a radical prostatectomy (RP), there is a risk of postoperative erectile dysfunction (ED). The incidence of ED following RP has been reported to be between 14% and 89%.² With an increase in the detection of prostate cancer in younger men, there is a greater emphasis on the appropriate management of ED after RP. With an early diagnosis of prostate cancer, there is an increase in the rate of RP in younger men and the importance of ED as a quality-of-life issue has subsequently increased.² There are a number of options available to manage ED after RP, including phosphodiesterase-5 (PDE-5) inhibitors, intracorporeal injections, intraurethral alprostadil, and vacuum erection devices (VEDs). Despite highly reported satisfaction and efficacy with VEDs, there is a move by some medical practitioners away from VEDs due to cost. But what evidence is there for VED success after prostatectomy and what role do VEDs have in penile rehabilitation after ED? We present current evidence and provide our recommendations based on the latest literature.     

The Small GTPase RhoA Is Required for Proper Locomotor Circuit Assembly

The assembly of neuronal circuits during development requires the precise navigation of axons, which is controlled by attractive and repulsive guidance cues. In the developing spinal cord, ephrinB3 functions as a short-range repulsive cue that prevents EphA4 receptor-expressing corticospinal tract and spinal interneuron axons from crossing the midline, ensuring proper formation of locomotor circuits. Here we report that the small GTPase RhoA, a key regulator of cytoskeletal dynamics, is also required for ephrinB3/EphA4-dependent locomotor circuit formation. Deletion of RhoA from neural progenitor cells results in mice that exhibit a rabbit-like hopping gait, which phenocopies mice lacking ephrinB3 or EphA4. Consistent with this locomotor defect, we found that corticospinal tract axons and spinal interneuron projections from RhoA-deficient mice aberrantly cross the spinal cord midline. Furthermore, we determined that loss of RhoA blocks ephrinB3-induced growth cone collapse of cortical axons and disrupts ephrinB3 expression at the spinal cord midline. Collectively, our results demonstrate that RhoA is essential for the ephrinB3/EphA4-dependent assembly of cortical and spinal motor circuits that control normal locomotor behavior.     

Drivers of <Emphasis Type="Italic">Bromus tectorum</Emphasis> Abundance in the Western North American Sagebrush Steppe

Bromus tectorum can transform ecosystems causing negative impacts on the ecological and economic values of sagebrush steppe of the western USA. Although our knowledge of the drivers of the regional distribution of B. tectorum has improved, we have yet to determine the relative importance of climate and local factors causing B. tectorum abundance and impact. To address this, we sampled 555 sites distributed geographically and ecologically throughout the sagebrush steppe. We recorded the canopy cover of B. tectorum, as well as local substrate and vegetation characteristics. Boosted regression tree modeling revealed that climate strongly limits the transformative ability of B. tectorum to a portion of the sagebrush steppe with dry summers (that is, July precipitation <10 mm and the driest annual quarter associated with a mean temperature >15°C) and low native grass canopy cover. This portion includes the Bonneville, Columbia, Lahontan, and lower Snake River basins. These areas are likely to require extreme efforts to reverse B. tectorum transformation. Our predictions, using future climate conditions, suggest that the transformative ability of B. tectorum may not expand geographically and could remain within the same climatically suitable basins. We found B. tectorum in locally disturbed areas within or adjacent to all of our sample sites, but not necessarily within sagebrush steppe vegetation. Conversion of the sagebrush steppe by B. tectorum, therefore, is more likely to occur outside the confines of its current climatically optimal region because of site-specific disturbances, including invasive species control efforts and sagebrush steppe mismanagement, rather than climate change.