Citrulline Accumulation Mechanism of Pediococcus acidilactici and Weissella confusa in Soy Sauce and the Effects of Phenolic Compound on Citrulline Accumulation

Citrulline is one of the major precursors of ethyl carbamate in soy sauce, and the accumulation of citrulline is attributed to the metabolism of arginine by bacteria with the arginine deiminase (ADI) pathway. However, key strains and factors affecting citrulline accumulation are not yet clear. In this study, two key strains of Pediococcus acidilactici and Weissella confusa were isolated from soy sauce moromi, and the regularity of citrulline formation was studied. Results showed that the conversion rates from arginine to citrulline (A/C rate) and the citrulline accumulation ability of W. confusa and P. acidilactici significantly increased in the presence of different concentrations of NaCl, indicating that salt stress was the main factor for citrulline accumulation. The inconsistent expression of arc genes by salt stress was the reason for citrulline accumulation for P. acidilactici, but for W. confusa, it may be due to the influence of arginine/citrulline on the transportation system: the intracellular citrulline could neither transport to extracellular space nor convert into ornithine. Environmental factors greatly influenced citrulline accumulation of the two key bacteria; A/C rate and citrulline formation in both strains decreased at low temperature (15°C) under high salt stress, but opposite effects were observed for the two key strains under anaerobic light condition. Moreover, quercetin and gallic acid significantly decreased the A/C rate and citrulline accumulation ability of the two key strains. The optimal quercetin and gallic acid as suggested by simulation experiment were 100 and 10 mg/l, respectively, and the lowest A/C rate of 28.4% and citrulline level of 1326.7 mg/l were achieved in the simulation system. This study explored the main factors for citrulline formation by the two key strains and proposed a targeted way to control citrulline in soy sauce.

Anthropogenic plutonium radioisotopes in the ecosystem components of Sevastopol Bay (the Black Sea)

Modern levels (2010-2020) of 239+240Pu activity concentration in Sevastopol Bay (Black Sea) surface waters, 0-5 cm layer of bottom sediments and hydrobionts were determined by multistage radiochemical technique. The 239+240Pu activity concentrations in Sevastopol Bay surface water were on relatively low level: 1.08±0.09 - 1.54±0.17 mBqnr3. The maximum value of 239+240Pu activity concentration in the bottom sediments surface layer was observed in Sevastopol Bay mouth (993±90 mBqkg1) and it decreased with distance from the bay entrance to its tail end down to the minimum value - 276±53 mBqkg1. Based on these results as well as on published data the 239+240Pu deposition density distribution in the bay boxes and their inventory in 0-5 cm layer of bottom sediments were estimated in every boxes. Total 239+240Pu inventory in the bottom sediments surface layer was estimated at 121 MBq, with the highest deposition density value determined in the mouth part of the bay. Among studied hydrobiont species the highest 239+240Pu content was determined for mollusks (for their shells) Mytilus galloprovincialis (Lamarck, 1819) while the lowest - for fish Scorpaena poreus (Linnaeus, 1758). Accumulation ability of studied ecosystem components of Sevastopol Bay against 239+240Pu was characterized by evaluating concentration factors (Cf). It was shown that the bottom sediments of the bay were the main depot for plutonium anthropogenic radionucludes (Cf (239+240Pu) = n-105). The Cf (239+240Pu) were from two to three orders of magnitude lower for the hydrobionts of the bay: n-103 for brown algae and mollusks and n-102 for green algae and fish.

Effects of Combined Nitrogen Deficient and Mixotrophic (+Glucose) Culture on the Lipid Accumulation of Parachlorella Kessleri TY

The combustion explosion of ordinary diesel is a global environmental problem. Green microalgae, which do not cause eutrophication, are a raw material that can be used to clean biodiesel. To increase lipid productivity, this study used a nitrogen deficient & mixotrophic (+Glucose) culture of lipid-producing microalgae Parachlorella kessleri TY from Shanxi Province, China. To examine the growth of P. kessleri TY, we measured dry weight, chlorophyll content, and chlorophyll fluorescence intensity under different culture conditions, in addition to the contents of neutral lipids, total lipids, and fatty acids, to examine its lipid accumulation ability. Cells were cultured in autotrophic, nitrogen deficient, mixotrophic (+Glucose), and nitrogen deficient & mixotrophic (+Glucose) conditions for 7 days. We found the growth of P. kessleri TY under nitrogen deficient & mixotrophic conditions was higher than that under the autotrophic and nitrogen deficient conditions, but lower than that under the mixotrophic (+Glucose) conditions. However, its lipid accumulation ability was significantly higher than that of control cultures. In conclusion, P. kessleri TY cultured under nitrogen-deficient and mixotrophic (+Glucose) conditions has significant lipid production capacity. Our results provide a theoretical basis for the use of microalgae as a raw material in the production of biodiesel, and promote the application of P. kessleri TY in large-scale production.

Amankah Mengkonsumsi Kerang Hijau Perna viridis L nnaeus, 1758 (Bivalvia: Mytilidae) yang ditangkap di Perairan Morosari Demak?

Kerang hijau (Perna viridis) merupakan komoditas perikanan yang sering dikonsumsi sebagai bahan pangan. Sampel yang diambil berasal dari perairan Morosari Demak pada bulan Juni, Juli dan Agustus 2020. Tujuan dari penelitian ini untuk menduga kandungan logam berat Pb dan Cu yang terdapat pada air, sedimen dan kerang hijau serta menentukan batas toleransi untuk mengkonsumsi kerang hijau yang mengandung logam berat. Penelitian ini bertujuan juga untuk menentukan Faktor biokonsentrasi (BCF) yang merupakan nilai akumulasi bahan kimia (polutan) dalam tubuh kerang. Penelitian ini menggunakan metode deskriptif, sedangkan metode penentuan lokasi menggunakan metode purposive sampling. Materi yang digunakan dalam penelitian ini adalah sampel kerang hijau, air dan sedimen. Parameter lingkungan seperti suhu, salinitas, oksigen terlarut, kecerahan, pH diukur secara in situ. Hasil penelitian menunjukkan nilai kandungan logam berat dalam daging kerang hijau berkisar 0,140-0,617 mg/kg (Pb) dan 0,035-0,851 mg/kg (Cu). Kandungan Pb dan Cu pada kerang hijau di semua stasiun dan bulan pengambilan sampel masih berada di bawah ambang batas yang ditetapkan oleh Badan Standardisasi Nasional (2009) untuk logam berat Pb sebesar 1,5 mg/kg dan FAO (1972) untuk logam berat Cu sebesar 1 mg/kg. Kemampuan kerang hijau dalam mengakumulasi logam berat Pb dan Cu pada setiap bulan bervariasi, sebagian besar memiliki kemampuan akumulasi organisme rendah dengan nilai FBK < 1, sebagian memiliki kemampuan akumulasi organisme sedang dengan nilai FBK >1 dan ≤2 dan beberapa memiliki kemampuan akumulasi organisme tinggi dengan nlai FBK >2. Analisis batas aman konsumsi kerang hijau yang tercemar logam berat pada lokasi penilitian menunjukan kerang hijau masih aman dikonsumsi hingga 2,43 kg/minggu pada orang dewasa dengan berat badan rata-rata 60 kg Green mussels, Perna viridis is a fishery commodity that is often consumed as a food. The purpose of this study is to evaluate the concentration of pb and cu heavy metals contained in water, sediment and green mussels. The sample was collected in Morosari coastal waters Demak in June, July and August 2020 and determine the tolerance limit for consuming green mussels containing heavy metals. This research aims to determine the bioconcentration factor (BCF) which is the value of accumulation of chemicals (pollutants) in the body of shellfish. Samples of green mussels were taken from three stations which are ponds of green mussels belonging to Morosari fishermen. This study uses descriptive method, while location determination method using purposive sampling method. The materials used in this study were samples of green mussels, water and sediment. Environmental parameters such as temperature, salinity, dissolved oxygen, brightness, pH are measured in situ. The results showed the value of heavy metals in green shellfish ranging from 0.140-0.617 mg/kg (Pb) and 0.035-0.851 mg/kg (Cu). The content of Pb and Cu in green mussels in all stations and months of sampling is still below the threshold set by the National Standardization Body (2009) for pb heavy metals of 1.5 mg/kg and FAO (1972) for Cu heavy metals of 1 mg/kg. The ability of green shells in accumulating heavy metals Pb and Cu on a monthly vary, most have low organism accumulation ability with BCF value < 1, some have the ability to accumulate medium organisms with BCF values >1 and ≤2 and some have high organism accumulation ability with BCF >2. Analysis of the safe limit of consumption of green mussels contaminated with heavy metals at the research site showed green mussels were still safe to consume up to 2.43 kg/week in adults with an average body weight of 60 kg.

Biomarkers in Pancreatic Cancer as Analytic Targets for Nanomediated Imaging and Therapy

As the increase in therapeutic and imaging technologies is swiftly improving survival chances for cancer patients, pancreatic cancer (PC) still has a grim prognosis and a rising incidence. Practically everything distinguishing for this type of malignancy makes it challenging to treat: no approved method for early detection, extended asymptomatic state, limited treatment options, poor chemotherapy response and dense tumor stroma that impedes drug delivery. We provide a narrative review of our main findings in the field of nanoparticle directed treatment for PC, with a focus on biomarker targeted delivery. By reducing drug toxicity, increasing their tumor accumulation, ability to modulate tumor microenvironment and even improve imaging contrast, it seems that nanotechnology may one day give hope for better outcome in pancreatic cancer. Further conjugating nanoparticles with biomarkers that are overexpressed amplifies the benefits mentioned, with potential increase in survival and treatment response.

Assessment of the Accumulation Ability of Festuca rubra L. and Alyssum saxatile L. Tested on Soils Contaminated with Zn, Cd, Ni, Pb, Cr, and Cu

The contamination of soils with metals applies, in particular, to areas related to industry, the mining of raw materials and ores, transport, and agriculture. Unlike organic materials, metals cannot degrade over time and need to be reduced, removed, or immobilized in soil. One of the remediation methods for soils contaminated with metals is phytoextraction, which uses plants’ ability to accumulate metals in their own tissues. Metals enter the plant organism through the roots and are transported to the aboveground parts, where they are accumulated. In this study, we evaluated the phytoaccumulative abilities of two plant species tested on soils from industrial areas contaminated with metals to different extents (Zn, Cd, Ni, Pb, Cr, and Cu). The research was conducted for three years under the conditions of a pot experiment. In order to obtain four soils with varying degrees of metal contamination, two soils from industrial areas, G1 (contaminated) and G2 (uncontaminated), were mixed in the following ratios: 1:1, 1:3, 1:7, and 1:9. In the phytoremediation process, Festuca rubra L. and Alyssum saxatile L. were tested. After analyzing the results of the bioconcentration factor (BCF) for the tested plants, it was noted that both of the tested plants accumulated Cd and Zn more easily, followed by Cu, Ni, and Cr, and then Pb to a lesser extent. The values of factors for Cd and Zn were correlated with the high mobility of these elements compared to other metals and their relatively easy uptake by plants. Alyssum saxatile L. has an ability to accumulate Cd compared to Festuca rubra L., which is confirmed by the BCF (0.764) and transfer factor (TF) (3.5) (for 1:7 combination) values. The calculated results for the BCFs for Alyssum saxatile L. are less than one for all tested metals, which allows us to state that Alyssum saxatile L. is not an accumulator.

The Addition of KNO3 and (NH4)3PO4 Maybe Improves the Ability to Accumulate Cd by Regulating the Redistribution of Nutrients in Bermudagrass

The application of fertilizer can improve the Cd enrichment efficiency of plants, but the changes of nitrogen (N), phosphorus (P), potassium (K) in the growth medium have different impacts on Cd enrichment efficiency of plants. In this study, hydroponic experiment by adding different KNO3 and (NH4)3PO4 was carried out to study whether and how the addition of available N, P and K can improve Cd accumulation. The four treatments were CK, 0.4 mg kg-1 Cd (Cd), 0.4 mg kg-1 Cd and KNO3 (COK), 0.4 mg kg-1 Cd and (NH4)3PO4 (CNP). The results showed that the chlorophyll contents, PSII maximum photochemical quantum efficiency (Fv/Fm) and PSII potential activity (Fv/Fo) of COK and CNP were higher than that of CD. There was no significant difference between CK and CNP (P > 0.05). The N, P and K contents and Cd concentrations of roots and stems of COK and CNP were significantly higher than those of CD(P＜0.05).The BCF of COK and CNP were also significantly higher than that of CD, increasing by 39.8% and 37.6%, respectively. The root, stem and leaf dry weight of COK and the root and stem dry weight of CNP were higher than that of CD, and the biomass of the whole basin was significantly higher than that of CD (P＜0.05), but with no significant difference from that of CK (P＞0.05). In addition to stem K accumulation of CNP, N, P and K allocated to root and stem in COK and CNP were significantly higher than that in CD (P＜0.05). There was no significant difference in pH and water soluble Cd content among CD, COK and CNP (P＞0.05). it was concluded that plants can improve their Cd accumulation ability by changing biomass and nutrient allocation. The conclusion provides a theoretical basis for improving soil environmental factors by improving fertilization strategies of related plants so as to improve Cd enrichment ability.

Processes and Mechanisms of Phosphorus Mobility Among Sediment, Water and Cyanobacteria Under Hydrodynamic Conditions

Phosphorus (P) has an important role in eutrophication and it is essential to explore the processes and mechanisms of P mobility in natural waters. In this study, laboratory experiments were conducted to simulate the SW system (sediment and water) and SAW system (sediment, algae and water) under four hydrodynamic intensity conditions (static control, 50 rpm, 125 rpm and 200 rpm treatments), to investigate P mobility. Results in SW system showed that, sediment was an important source of P for overlying water, and the released total P (TP) increased with stronger hydrodynamic intensity, when P associated with metal pools (redox-sensitive P [BD-P] and meta-oxides bound P [NaOH-P]) were the most unstable and easier to migrate into the overlying water. Stronger hydrodynamic disturbances could enhance the processes including sediment resuspension, dissolution of particles, and release of P, when P mobility had a close relationship with redox conditions near sediment-water interface (SWI). Therefore, the release of TP, BD-P and NaOH-P from sediment increased and decreased in the control and 50-200 rpm treatments over time. In SAW system, the release of TP significantly increased from sediment comparing to SW system, and the growth of Microcystis aeruginosa could selectively enhance the release of BD-P, NaOH-P, and organic P (OP). Meanwhile, the released P from sediment was quickly accumulated by algal cells. The maximum accumulation ability of P by cells, the highest photosynthetic efficiency and the best growth of M. aeruginosa were observed in 125 rpm treatment. But with excessively strong hydrodynamic intensity (200 rpm treatment), the accumulation ability of P and alkaline phosphatase activity (APA) of M. aeruginosa was suppressed, which might hinder algal utilization of P and inhibit algal growth. Overall, our findings demonstrated the patterns of P mobility in natural ecosystems and could contribute to the understanding of P cycling.