Abstract
In the last 240,000 years, males of the Drosophila simulans species clade have evolved striking differences in the morphology of their epandrial posterior lobes and claspers (surstyli). ...These appendages are used for grasping the female during mating and so their divergence is most likely driven by sexual selection. Mapping studies indicate a highly polygenic and generally additive genetic basis for these morphological differences. However, we have limited understanding of the gene regulatory networks that control the development of genital structures and how they evolved to result in this rapid phenotypic diversification. Here, we used new D. simulans/D. mauritiana introgression lines on chromosome arm 3L to generate higher resolution maps of posterior lobe and clasper differences between these species. We then carried out RNA-seq on the developing genitalia of both species to identify the expressed genes and those that are differentially expressed between the two species. This allowed us to test the function of expressed positional candidates during genital development in D. melanogaster. We identified several new genes involved in the development and possibly the evolution of these genital structures, including the transcription factors Hairy and Grunge. Furthermore, we discovered that during clasper development Hairy negatively regulates tartan (trn), a gene known to contribute to divergence in clasper morphology. Taken together, our results provide new insights into the regulation of genital development and how this has evolved between species.
Neurons have a membrane periodic skeleton (MPS) composed of actin rings interconnected by spectrin. Here, combining chemical and genetic gain- and loss-of-function assays, we show that in rat ...hippocampal neurons the MPS is an actomyosin network that controls axonal expansion and contraction. Using super-resolution microscopy, we analyzed the localization of axonal non-muscle myosin II (NMII). We show that active NMII light chains are colocalized with actin rings and organized in a circular periodic manner throughout the axon shaft. In contrast, NMII heavy chains are mostly positioned along the longitudinal axonal axis, being able to crosslink adjacent rings. NMII filaments can play contractile or scaffolding roles determined by their position relative to actin rings and activation state. We also show that MPS destabilization through NMII inactivation affects axonal electrophysiology, increasing action potential conduction velocity. In summary, our findings open new perspectives on axon diameter regulation, with important implications in neuronal biology.
Aims
This study evaluated the microbiological quality and safety of minimally processed parsley sold in southeastern Brazilian food markets.
Methods and Results
One hundred samples were submitted to ...the enumeration of Enterobacteriaceae by plating on MacConkey agar. Colonies of Enterobacteriaceae were randomly selected and identified by MALDI‐TOF MS. Samples were also tested for Listeria monocytogenes and Salmonella sp. The mean count of Enterobacteriaceae was 6·0 ± 1·0 log CFU per gram, while 18 genera (including 30 species) of bacteria belonging to this family were identified. Salmonella and L. monocytogenes were not detected, while L. innocua was found in two samples and L. fleischmannii was found in one sample. Moreover generic Escherichia coli was found in three samples, all from different brands of minimally processed parsley.
Conclusions
Even though microbial pathogens were not isolated, a variety of indicator micro‐organisms were identified, including vegetable spoilers and species capable of causing human opportunistic infections. These results suggest hygienic failures and/or lack of temperature control during processing and storage of these ready‐to‐eat products.
Significance and Impact of Study
This study highlights the need for control measures during the production chain of minimally processed parsley in order to reduce microbial contamination and the risks of foodborne diseases.
•Nano-TiO2 aqueous dispersions stabilized using novel mPEG-b-P4VP block copolymers.•For nanoparticles deagglomeration, ultrasonication proved to be the best technique.•Block copolymers had better ...stability than conventional polyelectrolyte dispersant.•Varnishes with TiO2/copolymers had better transparency and photocatalytic activity.
In this work, TiO2 nanoparticles were dispersed and stabilized in water using a novel type of dispersant based on tailor-made amphiphilic block copolymers of poly(ethylene glycol)-block-poly(4-vinyl pyridine) (mPEG-b-P4VP) prepared by atom transfer radical polymerization (ATRP). The performance of this new block copolymer as dispersant was compared to a polyelectrolyte dispersant commonly used for TiO2, sodium salt of polyacrylic acid (Na-PAA). The effect of dispersion technique and type and amount of dispersant on deagglomeration and stability of the TiO2 aqueous suspensions were studied. After incorporation in a standard waterborne acrylic varnish formulation, dry film transparency, photocatalytic activity, and nanoparticle cluster size were also evaluated. The results show that mPEG-b-P4VP copolymer with appropriate block lengths can have a better performance than Na-PAA in terms of aqueous dispersion stabilization and cluster size reduction in the acrylic matrix. This translates into higher film transparency and photocatalytic performance.
The solubility of
CO
2
in aqueous solutions of potassium glycinate was measured in a stirred reactor, at temperatures from 293 to 351
K, for amino acid salt concentrations ranging between 0.1 and
3.0
...mol
dm
-
3
and
CO
2
partial pressures up to
6
×
10
4
Pa
.
CO
2
solubility in potassium threonate
1.0
mol
dm
-
3
was also measured at 313
K. It was observed that amino acid salt solutions can be very interesting for
CO
2
absorption purposes since they present considerably high absorption capacities. Nevertheless,
CO
2
solubility in these solutions does not change significantly for temperatures between 293 and 323
K, which can be a draw back concerning the absorbent regeneration.
Potassium glycinate solubility data were interpreted using the thermodynamically sound model proposed by Deshmukh and Mather 1981. A mathematical-model for equilibrium solubility of hydrogen-sulfide and carbon-dioxide in aqueous alkanolamine solutions. Chemical Engineering Science 36 (2), 355–362 and the empirical Kent and Eisenberg 1976. Better data for amine treating. Hydrocarbon Processing 55(2), 87–90 model.
Nanodroplets' explosive vaporization triggered by absorption of laser pulses produces very large volume changes. These volume changes are two orders of magnitude higher than those of thermoelastic ...expansion generated by equivalent laser pulses, and should generate correspondingly higher photoacoustic waves (PAW). The generation of intense PAWs is desirable in photoacoustic tomography (PAT) to increase sensitivity. The biocompatibility and simplicity of nanodroplets obtained by sonication of perfluoropentane (PFP) in an aqueous solution of bovine serum albumin (BSA) containing a dye make them particularly appealing for use as contrast agents in clinical applications of PAT. Their usefulness depends on stability and reproducible vaporization of nanodroplets (liquid PFP inside) to microbubbles (gaseous PFP inside), and reversible condensation to nanodroplets. This work incorporates porphyrins with fluorinated chains and BSA labelled with fluorescent probes in PFP nanodroplets to investigate the structure and properties of such nanodroplets. Droplets prepared with average diameters in the 400-1000 nm range vaporize when exposed to nanosecond laser pulses with fluences above 3 mJ cm
−2
and resist coalescence. The fluorinated chains are likely responsible for the low vaporization threshold, ∼2.5 mJ cm
−2
, which was obtained from the laser fluence dependence of the photoacoustic wave amplitudes. Only
ca.
10% of the droplets incorporate fluorinated porphyrins. Nevertheless, PAWs generated with nanodroplets are ten times higher than those generated by aqueous BSA solutions containing an equivalent amount of porphyrin. Remarkably, successive laser pulses result in similar amplification, indicating that the microbubbles revert back to nanodroplets at a rate faster than the laser repetition rate (10 Hz). PFP nanodroplets are promising contrast agents for PAT and their performance increases with properly designed dyes.
Explosive vaporization of a nanodroplet increases generates a gigantic pressure wave.
Precise calorimetric reconstruction of 5–50 MeV electrons in liquid argon time projection chambers (LArTPCs) will enable the study of astrophysical neutrinos in DUNE and could enhance the physics ...reach of oscillation analyses. Liquid argon scintillation light has the potential to improve energy reconstruction for low-energy electrons over charge-based measurements alone. Here we demonstrate light-augmented calorimetry for low-energy electrons in a single-phase LArTPC using a sample of Michel electrons from decays of stopping cosmic muons in the LArIAT experiment at Fermilab. Michel electron energy spectra are reconstructed using both a traditional charge-based approach as well as a more holistic approach that incorporates both charge and light. A maximum-likelihood fitter, using LArIAT's well-tuned simulation, is developed for combining these quantities to achieve optimal energy resolution. A sample of isolated electrons is simulated to better determine the energy resolution expected for astrophysical electron-neutrino charged-current interaction final states. In LArIAT, which has very low wire noise and an average light yield of 18 pe / MeV , an energy resolution of σ / E ≃ 9.3 % / √ E ⊕ 1.3 % is achieved. Samples are then generated with varying wire noise levels and light yields to gauge the impact of light-augmented calorimetry in larger LArTPCs. At a charge-readout signal-to-noise of S / N ≃ 30 , for example, the energy resolution for electrons below 40 MeV is improved by ≈ 10 % , ≈ 20 % , and ≈ 40 % over charge-only calorimetry for average light yields of 10 pe / MeV , 20 pe / MeV , and 100 pe / MeV , respectively.
We report the discovery that the earwig predator Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae) feed on Puccinia polysora Underw uredospore, the causal agent of Southern Rust of Corn (SRC), ...which is a primary disease affecting the maize crop in Brazil. We performed experiments in laboratory and greenhouse to test the effect of D. luteipes (1st/2nd and 3rd/4th instars, and adults) fungivory on the P. polysora uredospore concentration. All trials showed a significant reduction of the initial concentration of uredospore. There was a reduction in uredospore concentration with increase in number of D. luteipes feeding on them. We also tested the uredospore consumption by quantifying its percentage in the feces of D. luteipes. Nymphs of the 2nd, 4th instar and adults fed 88%, 85%, and 83.8% of the uredospore, respectively. For nymphs of the 3rd instar, the percentage of uredospore consumption (75.6%) was statistically significant compared with the other groups. In greenhouse experiment, at twenty-eight days after plant inoculation with 9.9 x 104 uredospores, the percentage of uredospore consumption was 81.7%. Our results confirmed the fungivory of D. luteipes on P. polysora uredospore. This is the first report of D. luteipes fungivory, which may play an important role in the biological control of P. polysora in corn.
Although loneliness is a human experience, it can be estimated in laboratory animals deprived from physical contact with conspecifics. Rodents under social isolation (SI) tend to develop emotional ...distress and cognitive impairment. However, it is still to be determined whether those conditions present a common neural mechanism. Here, we conducted a series of behavioral, morphological, and neurochemical analyses in adult mice that underwent to 1 week of SI. We observed that SI mice display a depressive-like state that can be prevented by enriched environment, and the antidepressants fluoxetine (FLX) and desipramine (DES). Interestingly, chronic administration of FLX, but not DES, was able to counteract the deleterious effect of SI on social memory. We also analyzed cell proliferation, neurogenesis, and astrogenesis after the treatment with antidepressants. Our results showed that the olfactory bulb (OB) was the neurogenic niche with the highest increase in neurogenesis after the treatment with FLX. Considering that after FLX treatment social memory was rescued and depressive-like behavior decreased, we propose neurogenesis in the OB as a possible mechanism to unify the FLX ability to counteract the deleterious effect of SI.
Aqueous solutions of potassium glycinate were characterized for carbon dioxide absorption purposes. Density and viscosity of these solutions, with concentrations ranging from 0.1 to 3
M, were ...determined at temperatures from 293 to 313
K. Diffusivity of
CO
2
in solution was estimated applying the modified Stokes–Einstein relation. Solubilities of
N
2
O
at the same temperatures and concentrations were measured and the ion specific parameter based on Schumpe's model was determined for the glycinate anion; the solubilities of
CO
2
in these solutions were then computed.
The reaction kinetics of
CO
2
in the aqueous solution of potassium glycinate was determined at 293, 298 and 303
K using a stirred cell reactor. The results were interpreted using the DeCoursey equation for the calculation of the enhancement factor. The rate of absorption as a function of the temperature and solution concentration for the conditions studied was found to be given by the following expression:
-
r
CO
2
=
2.42
×
10
16
exp
-
8544
T
exp
(
0.44
C
S
)
C
S
C
CO
2
.
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