There has been a growing interest in traditional dairy (such as raw milk cheeses) and meat products, in recent years. However, these products are suitable and nutrient medium and may be easily ...contaminated by microorganisms such as
Enterobacteriaceae
.
Enterobacteriaceae
are considered to be the indicator bacteria for microbiological quality of food and hygiene status of a production process. Additionally, the food contaminated by
Enterobacteriaceae
poses a microbiological risk for consumers. In fact, the contamination of raw milk and meat by
Enterobacteriaceae
amid manufacturing may easily occur from various environmental sources, and this group of bacteria is frequently detected in dairy and meat products. Therefore, monitoring the microbiological quality of the used raw material and maintaining high standards of hygiene in the production process are mandatory for a high quality of traditional products and the safety of the potential consumers. The goal of this review is to present the most recent survey on
Enterobacteriaceae
growth, number, and distribution in raw milk cheeses and meat, as well as to discuss the sources of contamination and methods of control.
Key points
•
Enterobacteriaceae: role and importance in milk and meat products, EU legal regulations
•
Dynamics, distribution, and survival of Enterobacteriaceae in milk and meat
•
Mechanisms of control of Enterobacteriaceae in dairy products
Light-induced electron flow between reaction center and cytochrome bc1 complexes is mediated by quinones and electron donors in purple photosynthetic bacteria. Upon high-intensity excitation, the ...contribution of the cytochrome bc1 complex is limited kinetically and the electron supply should be provided by the pool of reduced electron donors. The kinetic limitation of electron shuttle between reaction center and cytochrome bc1 complex and its consequences on the photocycle were studied by tracking the redox changes of the primary electron donor (BChl dimer) via absorption change and the opening of the closed reaction center via relaxation of the bacteriochlorophyll fluorescence in intact cells of wild type and pufC mutant strains of Rubrivivax gelatinosus. The results were simulated by a minimum model of reversible binding of different ligands (internal and external electron donors and inhibitors) to donor and acceptor sides of the reaction center. The calculated binding and kinetic parameters revealed that control of the rate of the photocycle is primarily due to 1) the light intensity, 2) the size and redox state of the donor pool, and 3) the unbinding rates of the oxidized donor and inhibitor from the reaction center. The similar kinetics of strains WT and pufC lacking the tetraheme cytochrome subunit attached to the reaction center raise the issue of the physiological importance of this subunit discussed from different points of view.
A crucial factor for the efficacy of electron donors in photosynthetic photocycle is not just the substantial size of the pool and large binding affinity (small dissociation constant KD = koff/kon) to the RC, but also the mean residence time (koff)−1 in the binding pocket. This is an important parameter that regulates the time of re-activation of the RC during multiple turnovers. The determination of koff has proven challenging and was performed by simulation of widespread experimental data on the kinetics of P+ and relaxation of fluorescence. This work is a step towards better understanding the complex pathways of electron transfer in proteins and simulation-based design of more effective electron transfer components in natural and artificial systems.
•Cooperative redox control of electron transfer mechanisms in proteins.•Continuous and strong illumination drives the photocycle without cyt bc1 complex.•The rate of photocycle depends on the size and redox poise of the periplasmic donor pool.•The natural electron donors have similar binding affinities to the tetraheme cytochrome and to the reaction center.•Ligands to both sides of the reaction center limit the rate of the photocycle.
In photosynthetic bacteria, the absorbed light drives the canonical cyclic electron transfer between the reaction center and the cytochrome
bc
1
complexes via the pools of mobile electron carriers. ...If kinetic or structural barriers hinder the participation of the
bc
1
complex in the cyclic flow of electrons, then the pools of mobile redox agents must supply the electrons for the multiple turnovers of the reaction center. These conditions were achieved by continuous high light excitation of intact cells of bacterial strains
Rba. sphaeroides
and
Rvx. gelatinosus
with depleted donor side cytochromes c
2
(
cycA
) and tetraheme cytochrome subunit (
pufC
), respectively. The gradual oxidation by ferricyanide further reduced the availability of electron donors to
pufC
. Electron transfer through the reaction center was tracked by absorption change and by induction and relaxation of the fluorescence of the bacteriochlorophyll dimer. The rate constants of the electron transfer (~ 3 × 10
3
s
‒1
) from the mobile donors of
Rvx. gelatinosus
bound either to the RC (
pufC
) or to the tetraheme subunit (wild type) were similar. The electrons transferred through the reaction center dimer were supplied entirely by the donor pool; their number amounted to about 5 in wild type
Rvx. gelatinosus
and decreased to 1 in
pufC
oxidized by ferricyanide. Fluorescence yield was measured as a function of the oxidized fraction of the dimer and its complex shape reveals the contribution of two competing processes: the migration of the excitation energy among the photosynthetic units and the availability of electron donors to the oxidized dimer. The experimental results were simulated and rationalized by a simple kinetic model of the two-electron cycling of the acceptor side combined with aperiodic one-electron redox function of the donor side.
Ciomadul is the youngest volcano in the Carpathian‐Pannonian Region, Eastern‐Central Europe, which last erupted 30 ka. This volcano is considered to be inactive, however, combined evidence from ...petrologic and magnetotelluric data, as well as seismic tomography studies, suggests the existence of a subvolcanic crystal mush with variable melt content. The volcanic area is characterized by high CO2 gas output rate, with a minimum of 8.7 × 103 t/year. We investigated 31 gas emissions at Ciomadul to constrain the origin of the volatiles. The δ13C–CO2 and 3He/4He compositions suggest the outgassing of a significant component of mantle‐derived fluids. The He isotope signature in the outgassing fluids (up to 3.10 Ra) is lower than the values in the peridotite xenoliths of the nearby alkaline basalt volcanic field (R/Ra 5.95 Ra ± 0.01), which are representative of a continental lithospheric mantle and significantly lower than MORB values. Considering the chemical characteristics of the Ciomadul dacite, including trace element and Sr–Nd and O isotope compositions, an upper crustal contamination is less probable, whereas the primary magmas could have been derived from an enriched mantle source. The low He isotopic ratios could indicate a strongly metasomatized mantle lithosphere. This could be due to infiltration of subduction‐related fluids and postmetasomatic ingrowth of radiogenic He. The metasomatic fluids are inferred to have contained subducted carbonate material resulting in a heavier carbon isotope composition (δ13C is in the range of −1.4‰ to −4.6‰) and an increase of CO2/3He ratio. Our study shows the magmatic contribution to the emitted gases.
Plain Language Summary
Determining the fluxes and composition of gases in active and dormant volcanoes could help to constrain their origin. Ciomadul is the youngest volcano of the Carpathian‐Pannonian Region, Eastern‐Central Europe, where the last eruption occurred 30 ka. Its eruption chronology is punctuated by long quiescence periods (even >100 kyr) separating the active phases; therefore, the long dormancy since the last eruption (30 ka) does not unambiguously indicate inactivity. Knowing if melt‐bearing magma resides in the crust is fundamental to evaluate the nature of the volcano. Isotopic compositions of helium (3He/4He) and carbon (δ13CCO2) are important tools for the study of the origin of the gases. We show that the isotope variation of the emitted gases suggests a metasomatized lithospheric mantle origin for the primary magmas. This is consistent with a degassing deep magma body existing beneath Ciomadul, and this long‐dormant volcano cannot be considered as extinct.
Key Points
CO2 emissions at Ciomadul, Eastern‐Central Europe, suggest a still‐active plumbing system beneath the volcano in spite of long dormancy
The CO2 and He isotope compositions provide evidence for significant contribution of magma‐derived volatiles, up to 80%
Isotopic signatures of gases indicate that primary magmas could have derived from a mantle source modified by subduction‐related fluids
In this work, Cs
+
ion sorption on some clays and zeolite were investigated.
137
Cs was used as a tracer. Activities were measured with a NaI crystal gamma counter. The particle size distribution was ...determined by a laser sizer. Surface area of the particles were determined by BET (Brunauer, Emmett and Teller method). Structure analysis was made by using X-ray diffraction. The chemical compositions of the solid samples were determined using a ICAP-OE spectrometer. Kinetic and thermodynamic parameters were determined. Due to very high uptake results; clay and zeolite can be proposed as a good sorbents in waste management considerations.
The neoplastic process remains a major health problem facing humanity. Although there are currently different therapeutic options, they raise a multitude of shortcomings related to the toxic effects ...associated with their administration. Methotrexate (Met) and Cetuximab (Cet) are two basic chemotherapeutics used in cancer practice, but notwithstanding despite many years of use, the mechanisms by which the multitude of side-effects occur are not yet fully understood. Thus, the present study focused on the in vitro and in ovo evaluation of the associated toxic mechanisms on keratinocytes, keys cells in the wound healing process.
The two chemotherapeutics were tested in eight different concentrations to evaluate keratinocytes viability, the anti-migratory effect, and the influence on the expression of markers involved in the production of cell apoptosis. In addition, the potential irritating effect on the vascular plexus were highlighted by applying the in ovo method, chick chorioallantoic membrane (HET-CAM).
: The results revealed that Met induced decreased cell viability as well as increased expression of pro-apoptotic genes. In the vascular plexus of the chorioallantoic membrane, Met caused vascular irritation accompanied by capillary hemorrhage and vascular stasis.
: Summarizing, Cet presents a safer toxicological profile, compared to Met, based on the results obtained from both in vitro (cell viability, wound healing, RT-PCR assays), and in ovo (HET-CAM assay) techniques.
The design of a general-purpose PreAmplifier-DIscriminator ASIC chip, PADI, is presented in this article. PADI is intended to be used as Front-End-Electronics (FEE) for reading out the timing ...Resistive-Plate Chambers (RPCs) in the time-of-flight (ToF) wall of the CBM detector for the future FAIR facility in Darmstadt-Germany, which will comprise about 100,000 channels in a 150 m 2 area. The evolution of this 0.18 μm CMOS technology design will be presented, from the first prototype PADI-1 to the last one, PADI-8, as well as its features and test results.
The crtB gene of Synechocystis sp. PCC 6803, encoding phytoene synthase, was inactivated in the deltacrtH mutant to generate a carotenoidless deltacrtH/B double mutant. deltacrtH mutant cells were ...used because they had better transformability than wild-type cells, most probably due to their adaptation to partial carotenoid deficiency. Cells of the deltacrtH/B mutant were light sensitive and could grow only under light-activated heterotrophic growth conditions in the presence of glucose. Carotenoid deficiency did not significantly affect the cellular content of phycobiliproteins while the chlorophyll content of the mutant cells decreased. The mutant cells exhibited no oxygen-evolving activity, suggesting the absence of photochemically active PSII complexes. This was confirmed by 2D electrophoresis of photosynthetic membrane complexes. Analyses identified only a small amount of a non-functional PSII core complex lacking CP43, while the monomeric and dimeric PSII core complexes were absent. On the other hand, carotenoid deficiency did not prevent formation of the cytochrome bsub(6)f complex and PSI, which predominantly accumulated in the monomeric form. Radioactive labeling revealed very limited synthesis of inner PSII antennae, CP47 and especially CP43. Thus, carotenoids are indispensable constituents of the photosynthetic apparatus, being essential not only for antioxidative protection but also for the efficient synthesis and accumulation of photosynthetic proteins and especially that of PSII antenna subunits.
The development of CVD grown single-crystal Diamond-on-Iridium (DOI) sensors for charged-particle detection in hadrons and nuclei physics research is reviewed. A variety of samples grown at the ...University of Augsburg has been investigated with α and β sources in the laboratory, swift ions from the heavy-ion synchrotron SIS in Darmstadt, and relativistic protons from the COoler-SYnchrotron COSY in Jülich. The results obtained by means of I-E(V) studies, transient-current techniques (TCT), α-spectroscopy, and heavy-ion time-of-flight (ToF) measurements are compared to those of commercially available polycrystalline and homoepitaxial single crystal CVD diamond sensors of electronic grade quality.
In many aspects, the performance of DOI sensors was found quite similar to that of homoepitaxial counters, and in any case far superior to that of polycrystalline detectors. Under single-carrier drift conditions, the CCE and energy resolution (δE/E) for holes reached levels CCEh > 95% and δE/Eh ~ 0.3%, respectively, which correspond to values of the Schubweg wh,e well above the detector thickness. In contrast, the CCEe for electrons was typically lower than ~40%, leading to appreciable reduction of the detection efficiency in the dual-carrier drift mode (CCE ~ 60%), which characterizes the experiments with swift heavy ions and high-energy particles. We measured transport parameters comparable to those of homoepitaxial devices: μ0h ~ 3080–1756 and μ0e ~ 2276–1150 cm2/Vs, vsath ~ (1.7–1.4) ∗ 107 and vsate ~ (1.5–1.0) ∗ 107 cm/s, as well as intrinsic time resolutions σi ~ 15 ps. It is shown, that substantial improvements have been achieved in recent years, albeit reproducibility and the understanding of the reduced electron collection remain challenging issues.
Prime novelty: Comprehensive electrical characterization of intrinsic single-crystal CVD Diamond-On-Iridium sensors produced at the University of Augsburg and their classification into the range of commercial electronic grade polycrystalline and homoepitaxial diamond sensors supplied by Element Six.
Display omitted
•Comprehensive study exploring detector properties and perspectives of CVD Diamond-on-Iridium (DOI) produced in Augsburg.•DOI sensors are compared with commercial poly (PCD) and single-crystal CVD-diamond (SCD) samples supplied by Element Six.•The excellent drift and collection properties at h-drift enable particle timing and spectroscopy.•DOI sensors are clearly outperforming PCD counters.•The results indicate a high potential of heteroepitaxial diamond grown on Ir/YSZ/Si(001) for large-area detector systems.
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