Dark Conditions Research Articles

Cytotoxic and pro-oxidant profile of a photosensitive ruthenium nitrosyl candidate for NO delivery in healthy human fibroblasts.

Ruthenium nitrosyl (Ru-NO) complexes are of interest as photoactive nitric oxide (NO) donor candidates for local therapeutic applications. NO plays a crucial regulatory role in skin homeostasis, concentration-dependently affecting processes like the proliferation, apoptosis, autophagy and redox balance. In this context, we investigated HE-10, a ruthenium-based photoinducible NO donor, for its pro-oxidant and cytotoxic effects under light and dark conditions in VH10 human foreskin fibroblast cells. We also tested its intracellular and extracellular NO-releasing function. Our study reveals a significant dose-dependent cytotoxic effect of HE-10, an increase in intracellular reactive oxygen and nitrogen species, and the occurrence of apoptosis in skin fibroblast cells. Furthermore, exposure to both increasing doses of HE-10 and white LED light led to substantial cellular events, including a significant induction of autophagy and G2/M phase cell cycle arrest. Paradoxically, these effects were not solely attributable to NO release based on DAF2-DA NO probe results, suggesting that intracellular photochemical reactions additional to NO photolysis contribute to HE-10's biological activity. This study shows that HE-10 exhibits both cytotoxic and potential therapeutic effects, depending on concentration and light exposure. These findings are crucial for developing targeted Ru-NO complex treatments for skin diseases and potentially certain types of skin cancer, where controlled NO release could be beneficial.

Ultraviolet response of ZnO nanorod/Sb-doped ZnO thin film homojunction structure prepared by all-chemically wet process

In this work, ZnO nanorod/Sb-doped ZnO thin film structure was fabricated and its relevant properties were investigated. The device was prepared by Sb-doped ZnO sol-gel spin coating technique onto ITO substrate annealed in nitrogen atmosphere followed by the hydrothermal process to obtain ZnO nanorod. The crystal structure demonstrates (002) plane dominant hexagonal wurtzite ZnO without phase impurity. The deterioration in the crystal structure of Sb-doped ZnO due to the Sb is incorporated in the ZnO lattice. The element component in each layer is confirmed by depth profile measurement. The low transmittance in the visible region is due to high reflection at the surface of the ZnO nanorod. The electrical measurement confirms that ZnO nanorod/Sb-doped ZnO thin film has p-n homojunction properties under dark conditions and 18 times higher photovoltage than the Sb-doped/undoped ZnO double layer device under UV LED irradiation due to enhanced photon harvesting of ZnO nanorod structure.

Clonal propagation of rare orchid species Paphiopedilum spp. (Orchidaceae) to save Indonesian biodiversity

Paphiopedilum spp. is one of the terrestrial orchids that is interesting as an ornamental plant. This orchid flower has a distinctive characteristic, namely its labellum resembles a sac, so it is sought after by ornamental flower collectors because of its uniqueness. This orchid is included in the Appendix I group according to CITES, namely a critical species that is threatened with extinction, so it needs to be conserved both in situ and ex situ. Ex situ conservation can be done by propagating orchids using in vitro culture techniques. The objective of this research is to carry out mass propagation of 3 species of Paphiopedilum spp orchids: P. supardii, P. primulinum, P. glaucophyllum through somatic embryogenesis and to characterize the existence of embryo gene RKD4 homolog in Paphiopedilum orchids. The method is to culture the nodes slices in dark conditions for 2 weeks, and then changed to photoperiod mode 16:8 hours (dark:light) on ½ MS media plus a combination of 2,4-D or NAA with TDZ. The somatic embryo were analyzed anatomically. This method is an improvement over previously reported methods for Paphiopedilum spp. due to its efficiency and reproducibility for conservation. We concluded that ½ MS media with a combination of NAA or 2,4D with TDZ were able to induce somatic embryogenesis. The result show that 3 mg L−1 NAA was the best PGRs for PLBs induction in P. supardii (50 %), 1 mg L−1 2,4-D + 0.5 mg L−1 TDZ was the best PGRs for callus embryogenic induction in P. primulinum (20 %), and 1 mg L−1 NAA was the best PGRs for PLBs induction in P. glaucophyllum (33 %).

Investigation of the performance and stability of self-powered polythiophene-based photodiodes under UV and visible light illumination

In this study, we fabricated polythiophene (PTh) and silver-decorated polythiophene (Ag@PTh) films on n-type silicon substrates using the electrochemical deposition method to investigate their electrical and photoelectrical properties in metal/interlayer/n-Si heterostructures under various conditions. The physical properties of the films were comprehensively investigated through UV-Vis, Raman, XPS and SEM analysis. The results from these analyses confirmed the successful deposition and formation of the films on the n-Si substrates. Additionally, a comparison of the current-voltage (I-V) characteristics of the PTh/n-Si and Ag@PTh/n-Si devices was conducted under both dark conditions and illumination with visible and UV light. While both devices exhibited typical rectifying diode behavior, the Ag@PTh/n-Si device demonstrated greater rectification with a RR of 2.49 x 105 at ± 2 V under dark conditions. In addition, the Ag@PTh/n-Si device, with self-powered property, displayed notably enhanced performance metrics, including a significantly higher ON/OFF ratio, responsivity, and detectivity, particularly evident under UV light illumination when compared to white light. Furthermore, to assess the long-term reliability of these devices, stability tests were conducted by repeating the I-V measurements after 90 days under identical conditions. The Ag@PTh/n-Si device exhibited considerably better stability over time than the PTh/n-Si device, maintaining consistent performance without notable degradation. So, in light of the findings, it can be concluded that the Ag@PTh/n-Si device has substantial potential for advancing optoelectronic technology.

Porphyrin as Photosensitizers for Controlling Marine Biodegradation of Polymer Composites.

Biodegradable polymer-photosensitizer composites were developed, which is suppressed biodegradation due to bactericidal activity under light irradiation but proceeds under dark conditions. The composites exhibited antibacterial activity under light irradiation, which was attributed to the generation of singlet oxygen (1O2). Biodegradation was evaluated in seawater using the biochemical oxygen demand (BOD) method. In the dark, the composite and base polymer biodegraded to a similar degree. However, under light irradiation, the biodegradation of the composite was suppressed. In field tests, the rate of volume reduction of the composites decreased under illumination. The main cause of the suppression of biodegradation is suggested to be due to the decrease in the number of bacteria on the surface of the material and the inactivation of exoenzymes. The findings are expected to contribute to the development of biodegradable polymers that do not biodegrade during use but only when disposed of in the environment, thereby achieving on-demand degradation.

Maternal immune activation exerts long-term effects on activity and sleep in male offspring mice.

Exposure to infectious or non-infectious immune activation during early development is a serious risk factor for long-term behavioural dysfunctions. Mouse models of maternal immune activation (MIA) have increasingly been used to address neuronal and behavioural dysfunctions in response to prenatal infections. One commonly employed MIA model involves administering poly(I:C) (polyriboinosinic-polyribocytdilic acid), a synthetic analogue of double-stranded RNA, during gestation, which robustly induces an acute viral-like inflammatory response. Using electroencephalography (EEG) and infrared (IR) activity recordings, we explored alterations in sleep/wake, circadian and locomotor activity patterns on the adult male offspring of poly(I:C)-treated mothers. Our findings demonstrate that these offspring displayed reduced home cage activity during the (subjective) night under both light/dark or constant darkness conditions. In line with this finding, these mice exhibited an increase in non-rapid eye movement (NREM) sleep duration as well as an increase in sleep spindles density. Following sleep deprivation, poly(I:C)-exposed offspring extended NREM sleep duration and prolonged NREM sleep bouts during the dark phase as compared with non-exposed mice. Additionally, these mice exhibited a significant alteration in NREM sleep EEG spectral powerunder heightened sleep pressure. Together, our study highlights the lasting effects of infection and/or immune activation during pregnancy on circadian activity and sleep/wake patterns in the offspring.

Non-Covalent Interaction of Folic Acid and 5-Methyltetrahydrofolate with Caseinates Improves the Folates Stability Studied by Multi-Spectroscopic Analysis and Molecular Docking.

Folates, a crucial B-group vitamin, serve as a significant functional food supplement. Nevertheless, considerable obstacles persist in improving folates stability in liquid products. In this study, folic acid (FA) and 5-methyltetrahydrofolate (MTFA), two approved sources of folates, were encapsulated with sodium caseinate (NaCas) to enhance their stability. The protective effect of NaCas on folate molecules was investigated using experimental and computational methods. Meanwhile, the influence of divalent calcium ion (Ca2+) on the properties of the NaCas-MTFA complex was examined to evaluate the potential application of calcium 5-methyltetrahydrofolate (CaMTFA). Fluorescence tests showed both folates had static quenching behavior and bound to NaCas with a binding constant of 104-105 M-1. Hydrophobic interactions were crucial in NaCas-FA complex formation, while hydrogen bonding drove NaCas-MTFA binding. The encapsulation of caseinate notably slowed down the degradation of folates under both light and dark conditions. Moreover, the addition of a low concentration of Ca2+ did not adversely impact the binding mechanism of the NaCas-MTFA complex or the degradation curve of MTFA. The results of this study could serve as a valuable resource for the utilization of caseinates in incorporating folates, specifically MTFA, in the creation of natural liquid dietary supplements.

Comprehensive Understanding on the Aging Process and Mechanism of Microplastics in the Sediment-Water Interface: Untangling the Role of Photoaging and Biodegradation.

Microplastics (MPs) in coastal wetlands have been of great concern, but information on the aging behavior of MPs in the sediment-water interface is still lacking. In this study, the contribution of a typical abiotic (photoaging) and biotic (biodegradation) process and the underlying aging pathway of MPs with different degradabilities (including polypropylene, polyethylene terephthalate, and polylactic acid) were studied. With a quantified relative importance of photoaging (>55%) vs biodegradation, the crucial contribution of photoaging on MP aging was highlighted. This was likely attributed to more generation of reactive oxygen species (ROS) under sunlight irradiation conditions, containing O2•- and H2O2. By raising higher the level of malondialdehyde (0.5-3.5 times as high as that in the dark condition), these photochemically formed ROS caused oxidative stress and inhibited the selective attachment of plastic-degrading microbes on the MP surface, thereby weakening the effect of biodegradation. On this basis, the aging characteristics and potential pathway of different MPs were revealed. The functional group of nondegradable polypropylene tends to be broken by ROS first, while biodegradation (Arthrobacter oryzae and Bacillus sp.) played a relatively dominant role in biodegradable polylactic acid. This study provides a new sight for the understanding on the aging behaviors of MPs in the sediment-water interface.

The Abundance and Sources of Ice Nucleating Particles Within Alaskan Ice Fog

AbstractThe Alaskan Layered Pollution and Chemical Analysis (ALPACA) field campaign included deployment of a suite of atmospheric measurements in January–February 2022 with the goal of better understanding atmospheric processes and pollution under cold and dark conditions in Fairbanks, Alaska. We report on measurements of particle composition, particle size, ice nucleating particle (INP) composition, and INP size during an ice fog period (29 January–3 February). During this period, coarse particulate matter (PM10) concentrations increased by 150% in association with a decrease in air temperature, a stronger temperature inversion, and relatively stagnant conditions. Results also show a 18%–78% decrease in INPs during the ice fog period, indicating that particles had activated into the ice fog via nucleation. Peroxide and heat treatments performed on INPs indicated that, on average, the largest contributions to the INP population were heat‐labile (potentially biological, 63%), organic (31%), then inorganic (likely dust, 6%). Measurements of levoglucosan and bulk and single‐particle composition corroborate the presence of dust and aerosols from combustion sources. Heat‐labile and organic INPs decreased during the peak period of the ice fog, indicating those were preferentially activated, while inorganic INPs increased, suggesting they remained as interstitial INPs. In general, INP concentrations were unexpectedly high in Fairbanks compared to other locations in the Arctic during winter. The fact that these INPs likely facilitated ice fog formation in Fairbanks has implications for other high latitude locations subject to the hazards associated with ice fog.

Advancements in CIGS/ZnS heterojunction solar cells: Experimental and numerical analysis

This study presents a comprehensive experimental investigation conducted on a CIGS-based solar cell incorporating a ZnS buffer layer. The primary objective was to determine key parameters of the CIGS/ZnS heterojunction, including parasitic resistances (Rs and Rsh), ideality factor (n), and barrier height (ϕB), using experimental current-voltage (I-V) characteristics over a temperature range of 150 K to 300 K under dark conditions. The heterojunction was modelled using a single-diode electrical circuit that accounted for parasitic resistances. Two methods were employed for parameter determination: direct analysis of the (I-V) curves and Cheung's method. Additionally, the charge transport mechanism within the heterojunction is investigated and discussed. Furthermore, the performance of the Al:ZnO/i:ZnO/ZnS/CIGS/Mo solar cell was assessed using the SCAPS-1D simulator, demonstrating an initial solar energy conversion efficiency of 15.01 %. To enhance this efficiency, a hole transport layer (HTL) was integrated between the back electrode and the absorber layer. Extensive studies were conducted to optimize the thickness and doping density of the HTL, including a comparative analysis of different materials used as HTLs. These optimizations resulted in a significant increase in conversion efficiency, reaching up to 28.68 %.

Spontaneous Molecular Bromine Production in Sea‐Salt Aerosols

AbstractBromine chemistry is responsible for the catalytic ozone destruction in the atmosphere. The heterogeneous reactions of sea‐salt aerosols are the main abiotic sources of reactive bromine in the atmosphere. Here, we present a novel mechanism for the activation of bromide ions (Br−) by O2 and H2O in the absence of additional oxidants. The laboratory and theoretical calculation results demonstrated that under dark conditions, Br−, O2 and H3O+ could spontaneously generate Br and HO2 radicals through a proton–electron transfer process at the air–water interface and in the liquid phase. Our results also showed that light and acidity could significantly promote the activation of Br− and the production of Br2. The estimated gaseous Br2 production rate was up to 1.55×1010 molecules cm−2 ⋅ s−1 under light and acidic conditions; these results showed a significant contribution to the atmospheric reactive bromine budget. The reactive oxygen species (ROS) generated during Br− activation could promote the multiphase oxidation of SO2 to produce sulfuric acid, while the increase in acidity had a positive feedback effect on Br− activation. Our findings highlight the crucial role of the proton‐electron transfer process in Br2 production; here, H3O+ facilitates the activation of Br− by O2, serves as a significant source of atmospheric reactive bromine and exerts a profound impact on the atmospheric oxidation capacity.

Extracellular vesicle-mediated secretion of chlorophyll biosynthetic intermediates in the cyanobacterium Leptolyngbya boryana.

Extracellular vesicles (EVs) are derived from the outer membrane (OM) in Gram-negative bacteria and have diverse physiological functions. EV-mediated secretion of monovinyl protochlorophyllide (MV-Pchlide), the chlorophyll a (Chl) biosynthetic intermediate, was previously reported in a mutant lacking dark-operative Pchlide reductase in the cyanobacterium Leptolyngbya boryana. This study showed a detailed characterization of EVs from the wild-type (WT) of L. boryana grown under photoautotrophic and dark heterotrophic conditions, focusing on the accumulation of Chl intermediates. WT L. boryana cells produce two types of EVs, low-density EVs (L-EVs) and high-density EVs (H-EVs), both under light and dark conditions. L-EVs and H-EVs showed distinct morphological features and protein compositions. L-EVs from cells grown under both light and dark conditions commonly contained carotenoids, ketomyxol glycoside, and zeaxanthin, as major pigments. Based on the protein compositions of EVs and other cellular membrane fractions, L-EVs and H-EVs are probably derived from low-density OM and high-density OM interacting with cell walls, respectively. Fluorescence detection of pigments was applied to EVs, and the two Chl intermediates, protoporphyrin IX and protoporphyrin IX monomethyl ester, were commonly detected in both L-EVs from light- and dark-grown cells, whereas L-EVs from dark-grown cells contained additional MV-Pchlide, MV-protopheophorbide, and pheophorbide. The pigment ratios of L-EVs to the total culture medium of the Chl intermediates were much higher than those of carotenoids, suggesting an active transport of the Chl intermediates from the thylakoid membrane to L-EVs. Cyanobacterial EVs may play a novel role in alleviating the accumulation of Chl intermediates in cells. (248 words).

Enhanced photodiode performance: Au/boron-dipyrromethene/n-Si/Ag structure unveiling high photosensitivity and efficiency

In this study, the classical boron-dipyrromethene (4,4- difuoro-4-borata-3a-azonia-4a-aza-s-indacene, BODIPY) unit (C1), its halogenated derivative (C2), and disytryl derivative (C3), which are known for their absorption properties in the near-infrared (NIR) region, were synthesized. Chemical and photophysical investigations were carried out to reveal the complex features of the molecules using a range of spectroscopic techniques and their energies were calculated by Density Functional Theory (DFT) with the same basis set. The BODIPY thin films were coated on n-Si substrates using a spin coater to examine the effect of interlayer on photodiode/photovoltaic properties and Au/BODIPY (C1, C2, C3)/n-Si/Ag photodiodes having rectifying behavior were fabricated. The thermionic emission theory (TET) and modified Norde’s functions were utilized to determine the rectification ratio, ideality factor, series resistance, and barrier height values of diodes. The values of barrier height, ideality factor, and rectification ratio at ± 2 V were calculated as 0.81 eV, 1.83 and 2.47x103 for the Au/C1/n-Si/Ag diode, 0.83 eV, 1.63, and 7.06 x103 for the Au/C2/n-Si/Ag diode and 0.84 eV, 1.51 and 2.14x104 for the Au/C3/n-Si/Ag diode in the dark from the TET, respectively. The values of FF (%) and efficiency were calculated as 38 and 1.51 for the Au/C1/n-Si/Ag diode, 47 and 2.03 for the Au/C2/n-Si/Ag diode, and 56 and 3.68 for the Au/C3/n-Si/Ag diode under 100 mW/cm2 illumination, respectively. With remarkable electrical properties, the Au/C3/n-Si/Ag photodiode stood out among the others, performing better in both dark and light conditions. Therefore, the produced diodes based on the BODIPY thin film can be employed as photodiodes/photovoltaics in optoelectronic applications.

First Report of Neopestalotiopsis clavispora Causing Fruit Brown Spot of Pomegranate in China.

Pomegranate (Punica granatum) is an important fruit crop for therapeutic and food applications. In June 2022, brown spots were observed on the fruit surface of pomegranate cultivar named Guangyan in Mengzi (23°20'6''N,103°25'5''E), Yunnan, China. The early spots appeared as circular or irregular lesions, measuring 1~1.5 mm in diameter. They were light brown with a clear boundary between disease and healthy tissues. Over time, these spots developed into polygonal lesions covering the entire fruit surface. Eventually, the diseased fruits decayed, and more than 50% of fruits were infected in pomegranate orchards. The tissues from the interface between health and disease were cut down, immersed in 75% ethanol for 15 s, then 5% NaOCl disinfecting for 2 min, washed three times with sterile water, and the PDA cultured at 26 °C in an incubator under dark conditions. Twenty-five samples were collected for pathogen isolation, ten fungal isolates were obtained by single spore germination, and these isolates had similar morphological characters. The colonies were white with 81 mm diameter at 7 days of incubation, containing undulate edges with dense aerial mycelium. After 14 days, the black conidiomata formed superficially, gathering into black droplets. Conidiogenous cells were hyaline, short, and filiform. Conidia were fusiform, straight or slightly curved, and comprised five cells, 24.12 to 34.53 (x̄=29.78) μm × 4.21 to 12.15 (x̄=8.68) μm (n=50). The three median cells were 13.13 to 25.22 μm (x̄=18.54), dark brown, whose septa and periclinal walls were darker than the other two cells. The apical cells showed two to four appendages, 12.31 to 29.15 (x̄=21.56) μm. Only a single appendage was found on the basal cell, 2.34 to 7.16 μm. Based on morphological features, these isolates were identified as Neopestalotiopsis clavispora (Maharachchikumbura et al., 2012, 2014). Molecular identification of isolate YNSL-3 was performed by amplification and sequencing of ITS4/ITS5, BT2A/ BT2B and EF1-728F/EF-2, respectively (White et al. 1990, Glass et al.1995, Carbone et al. 1999, O'Donnell et al. 1998). These base sequences were deposited in GenBank with accession numbers OQ891378 (ITS), OR088917 (Tef) and OR513439(Tub), respectively. BLAST searches of the sequences revealed 100% (478/478 bp), 100% (484/484 bp), and 94.67% (426/450 bp) homology with those of N. clavispora NM16311a from GenBank (LC209216, LC209220, and LC209221), respectively. Phylogenetic analysis (IQ-TREE) by maximum likelihood method showed that the isolate YNSL-3 was clustered with N. clavispora. The pathogenicity was tested with the isolate of YNSL-3, YNSL-5 and YNSL-8 by detached assay. The fruit surface of pomegranate cultivar Guangyan was wounded with a sterilized needle. The mycelial blocks (5mm2) of isolates cultured on PDA for 7 days were attached to the points of inoculation. Controls were inoculated with sterile PDA agar. All inoculated fruits were maintained in a growth chamber at 26°C with 75% relative humidity. The test was performed thrice. The brown lesions were observed after 7 days, whereas the controls showed no symptoms. The same pathogens reisolated were identical to the original isolates based on morphological characterization and molecular analyses. N. clavispora could cause different diseases in many plants (Rajashekara et al. 2023, Loredana et al. 2020). To our knowledge, this is the first report of fruit brown spot on Punica granatum caused by N. clavispora in China. This finding will help improve management strategies against the fruit brown spots on P. granatum in China.

Synergistic effect of oxygen vacancies and in-situ formed bismuth metal centers on BiVO4 as an enhanced bifunctional Li–O2 batteries electrocatalyst

Bismuth Vanadate (BiVO4) is a promising oxide-based photoanode for electrochemical applications, yet its practical use is constrained by poor charge transport properties, particularly under dark conditions. This study introduces a novel BiVO4 variant (Bi-BiVO4-10) that incorporates abundant oxygen vacancies and in-situ formed Bi metal, significantly enhancing its electrical conductivity and catalytic performance. Bi-BiVO4-10 demonstrates superior electrochemical performances compared to conventional BiVO4 (C-BiVO4), demonstrated by its most positive half-wave potential with the highest diffusion-limiting current in the oxygen reduction reaction (ORR) and earliest onset potential in the oxygen evolution reaction (OER). Notably, Bi-BiVO4-10 is explored for the first time as an electrocatalyst for lithium-oxygen (Li–O2) cells, showing reduced overcharge (610 mV) in the first cycle and extended cycle life (1050 h), outperforming carbon (320 h) and C-BiVO4 (450 h) references. The enhancement is attributed to the synergy of oxygen vacancies, Bi metal formation, increased surface area, and improved electrical conductivity, which collectively facilitate Li2O2 growth, enhance charge transport kinetics, and ensure stable cycling. Theoretical calculations reveal enhanced chemical interactions between intermediate molecules and the defect-rich surfaces of Bi-BiVO4-10, promoting efficient discharge and charge processes in Li–O2 batteries. This research highlights the potential of unconventional BiVO4-based materials as durable electrocatalysts and for broader electrochemical applications.

Solvent-Directed Bioactive Supramolecular Zinc(II)-Metallogels: Exploring Semiconducting Aptitudes of Fabricating p-n Junction and Schottky Devices.

α-Ketoglutaric acid-based supramolecular Zn(II) metallogels in N,N'-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solvent (i.e., Zn-α-Glu-DMF and Zn-α-Glu-DMSO) were successfully achieved. Zinc(II) acetate salt and α-ketoglutaric acid directed a three-dimensional noncovalent supramolecular network individually entrapped with N,N'-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) solvent to accomplish their respective semisolid flexible metallogel frameworks. The gel features of these synthesized materials were verified by rheological experiments such as amplitude sweep and frequency sweep measurements. The discrete morphological arrangements were analyzed for these metallogel samples through field emission scanning electron microscopic (FESEM) analysis. Highly stacked interconnected blocks of Zn-α-Glu-DMF with hierarchical arrays are found due to the occurrence of diverse noncovalent supramolecular interactions present in the metallogel framework. A distinct spherical shaped microstructure with interconnected hierarchical assembly has been observed for the FESEM pattern of Zn-α-Glu-DMSO. FTIR spectroscopic measurement was carried out to detect some important stretching vibrations of xerogel samples of different metallogels as well as gel-constructing chemical ingredients. A substantial amount of peak shifting of xerogel samples for both metallogels is observed in FTIR analysis, indicating the presence of different noncovalent interactions. ESI-mass analysis portrays a possible metallogel-constructing strategy. The antibacterial potentialities of both metallogels were investigated. These materials exhibited good antimicrobial efficacy toward Gram-positive and Gram-negative bacterial strains (including Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Salmonella typhimurium). Both synthesized metallogels were successfully implemented to fabricate the photoresponsive semiconducting diode. These materials offer excellent photodiode parameters including an ideality factor and rectification ratio (ON/OFF ratio). Synthesized metallogels are used to successfully fabricate photodiodes with an Al/p-Si/metallogel/Au structure. The ideality factors (η) for Zn-α-Glu-DMF and Zn-α-Glu-DMSO are found as 1.3 and 2.3, respectively, in dark conditions. The rectification ratios for Zn-α-Glu-DMF and Zn-α-Glu-DMSO metallogels are also determined, and these are found as 40 and 10, respectively.

Characteristics and performance of algal–bacterial granular sludge in photo-sequencing batch reactors under various substrate loading rates

The algae–bacterial granular sludge (ABGS) technology has garnered significant attention due to its remarkable attributes of low carbon emissions. To investigate the performance of the ABGS system under various substrate loading rates, the parallel photo-sequencing batch reactors (P1 and P2) were set up. The results indicated that chlorophyll-a content and extracellular polymeric substance content were measured at 10.7 ± 0.3 mg/L and 61.4 ± 0.7 mg/g SS in P1 under relatively low substrate loading rate (0.9 kg COD/m3/d and 0.09 kg N/m3/d). Moreover, kinetic study revealed that the maximal specific P uptake rate for P1 reached 0.21 mg P/g SS/h under light conditions, and it achieved 0.078 mg P/g SS/h under dark conditions, highlighting the significant role on phosphorus removal played by algae in the ABGS system. The microbial analysis and scanning electron microscopy confirmed that filamentous algae predominantly colonize the surface in P1, whereas spherical bacteria dominate the surface of granular sludge in P2. Additionally, a diverse array of microorganisms including bacteria, algae, and metazoa such as Rotifers and Nematodes were observed in both systems, providing evidence for the establishment of a symbiotic system. This study not only confirmed the ability of ABGS for efficient N and P removal under different substrate loading conditions but also highlighted its potential to enhance the ecological diversity of the reaction system.

Exploring bee venom and silver nanoparticles for controlling foulbrood pathogen and enhancing lifespan of honeybees

The beekeeping industry plays a crucial role in local economies, contributing significantly to their growth. However, bee colonies often face the threat of American foulbrood (AFB), a dangerous disease caused by the Gram-positive bacterium Paenibacillus larvae (P. l.). While the antibiotic Tylosin has been suggested as a treatment, its bacterial resistance necessitates the search for more effective alternatives. This investigation focused on evaluating the potential of bee venom (BV) and silver nanoparticles (Ag NPs) as antibacterial agents against AFB. In vitro treatments were conducted using isolated AFB bacterial samples, with various concentrations of BV and Ag NPs (average size: 25nm) applied individually and in combination. The treatments were administered under both light and dark conditions. The viability of the treatments was assessed by monitoring the lifespans of treated bees and evaluating the treatment's efficiency within bee populations. Promising results were obtained with the use of Ag NPs, which effectively inhibited the progression of AFB. Moreover, the combination of BV and Ag NPs, known as bee venom/silver nanocomposites (BV/Ag NCs), significantly extended the natural lifespan of bees from 27 to 40 days. Notably, oral administration of BV in varying concentrations (1.53, 3.12, and 6.25 mg/mL) through sugary syrup doubled the bees' lifespan compared to the control group. The study established a significant correlation between the concentration of each treatment and the extent of bacterial inhibition. BV/Ag NCs demonstrated 1.4 times greater bactericidal efficiency under photo-stimulation with visible light compared to darkness, suggesting that light exposure enhances the effectiveness of BV/Ag NCs. The combination of BV and Ag NPs demonstrated enhanced antibacterial efficacy and prolonged honeybee lifespan. These results offer insights that can contribute to the development of safer and more efficient antibacterial agents for maintaining honeybee health.

Multiplex Approach of Metabolomic and Transcriptomic Reveals the Biosynthetic Mechanism of Light-induced Flavonoids and CGA in Chrysanthemum

Light, as an important environmental signal for plant growth and development, has been reported to be involved in the metabolism of phenylpropane. However, the light-induced phenylpropane biosynthesis mechanism in Chrysanthemum morifolium Ramat., especially flavonoid and chlorogenic acid (CGA) metabolism, is not clear. In this study, we found the flower phenotype of chrysanthemum 'HangBaiJu' became lighter after bagging. Besides, the content of main active ingredients, such as Luteolin-7-O-glucoside (Lu-7-O-G), Diosmetin-7-O-glucoside (Di-7-O-G), Apigenin-7-O-glucoside, Apigenin and CGA, was significantly decreased. Comparative transcriptome analysis (pairwise comparison, WGCNA, and k-means clustering) revealed that the expression of structural genes, such as CmPAL, CmCHS1/2, CmF3’H, CmFNS and CmHQT, was notably declined under dark conditions. Meanwhile, ‘bridge proteins’ CmMYB3/6/16 and signal transduction factors CmBBX20/22.2/22.3 were identified as key regulatory factors in the light-mediated synthesis of flavonoids and CGA in chrysanthemum. Among that, CmBBX20 could promote the accumulation of flavonoids and CGA by directly binding to the G-box core sequences of downstream target genes based on transient overexpression and Y1H assays. Overall, the preliminary molecular mechanism of BBXs and MYBs coordinately regulating the accumulation of flavonoids and CGA in chrysanthemum under different light inductions has been clarified, which provided a theoretical basis for the molecular breeding and quality improvement of chrysanthemum.

Transcriptome-Wide Identification of Dark- and Salt-Induced Senescence-Related NAC Gene Family Members in Alfalfa.

Leaves are a key forage part for livestock, and the aging of leaves affects forage biomass and quality. Preventing or delaying premature leaf senescence leads to an increase in pasture biomass accumulation and an improvement in alfalfa quality. NAC transcription factors have been reported to affect plant growth and abiotic stress responses. In this study, 48 NAC genes potentially associated with leaf senescence were identified in alfalfa under dark or salt stress conditions. A phylogenetic analysis divided MsNACs into six subgroups based on similar gene structure and conserved motif. These MsNACs were unevenly distributed in 26 alfalfa chromosomes. The results of the collinearity analysis show that all of the MsNACs were involved in gene duplication. Some cis-acting elements related to hormones and stress were screened in the 2-kb promoter regions of MsNACs. Nine of the MsNAC genes were subjected to qRT-PCR to quantify their expression and Agrobacterium-mediated transient expression to verify their functions. The results indicate that Ms.gene031485, Ms.gene032313, Ms.gene08494, and Ms.gene77666 might be key NAC genes involved in alfalfa leaf senescence. Our findings extend the understanding of the regulatory function of MsNACs in leaf senescence.