Identification and functional analysis of floral terpene synthase genes in Curcuma alismatifolia.

MAIN CONCLUSION: CaTPS2 and CaTPS3 were significantly expressed in flowers of Curcuma alismatifolia 'Shadow' and demonstrated bifunctional enzyme activity, CaTPS2 generated linalool and nerolidol as products, and CaTPS3 catalyzed ß-myrcene and ß-farnesene formation. This study presents the discovery and functional characterization of floral terpene synthase (TPS) genes in Curcuma alismatifolia 'Shadow', a cultivar renowned for its unique fragrance. Addressing the gap in understanding the genetic basis of floral scent in this species, we identified eight TPS genes through comprehensive transcriptome sequencing. Among these, CaTPS2 and CaTPS3 were significantly expressed in floral tissues and demonstrated bifunctional enzyme activity corresponding to the major volatile compounds detected in 'Shadow'. Functional analyses, including in vitro assays complemented with rigorous controls and alternative identification methods, elucidated the roles of these TPS genes in terpenoid biosynthesis. In vitro studies were conducted via heterologous expression in E. coli, followed by purification of the recombinant protein using affinity chromatography, enzyme assays were performed with GPP/FPP as the substrate, and volatile products were inserted into the GC-MS for analysis. Partially purified recombinant protein of CaTPS2 catalyzed GPP and FPP to produce linalool and nerolidol, respectively, while partially purified recombinant protein of CaTPS3 generated ß-myrcene and ß-farnesene with GPP and FPP as substrates, respectively. Real-time quantitative PCR further validated the expression patterns of these genes, correlating with terpenoid accumulation in different plant tissues. Our findings illuminate the molecular mechanisms underpinning floral fragrance in C. alismatifolia and provide a foundation for future genetic enhancements of floral scent in ornamental plants. This study, therefore, contributes to the broader understanding of terpenoid biosynthesis in plant fragrances, paving the way for biotechnological applications in horticulture plant breeding.

Different responses of taxonomic and functional trait structure of benthic macroinvertebrate assemblages to eutrophication in a large Chinese freshwater lake.

Functional trait measures have the potential to represent local habitat conditions and are considered promising tools for biomonitoring and bioassessment programs. Macroinvertebrates are an ecologically significant group in freshwater ecosystems and possess a range of functional traits which are employed to assess ecological quality. Nevertheless, the relationships between macroinvertebrate functional structure and anthropogenic disturbances remain poorly understood. In this study, we conducted a comparison of how functional trait-based and taxonomy-based composition of macroinvertebrate assemblages responded to eutrophication in Lake Taihu, a typical large eutrophic freshwater lake in China. Specifically, we examined both the taxonomy-based and trait-based compositions of benthic macroinvertebrates varied along the eutrophication gradient. Eutrophication was associated with remarkable decreases in the abundance of gastropod taxa and increases in Oligochaeta and Chironomidae. Ten categories belonging to six traits were significantly different among three site groups. The eutrophic and transition sites showed higher abundance of Size2, burrowers, and integument-respiration organisms than macrophytic sites, whereas abundance of Size1, conical-shaped, sprawlers, scrapers, and lung-respiration were higher in macrophytic sites. Both taxonomic (36.8%) and functional compositions (39.8%) of macroinvertebrate assemblages were influenced by the same variables: CODMn and transparency. Our study showed that macroinvertebrate trait-based approaches can be considered a useful supplement to traditional taxonomic approach for biomonitoring programs in freshwater lakes.

Degradation of Alternaria mycotoxins by UV-C irradiation: Effect of selected process and exposure to food components.

Alternariol (AOH) and alternariol monomethyl ether (AME) are two Alternaria mycotoxins with high occurrence rates in food systems. This study aimed to investigate the photodegradation of AOH and AME by ultraviolet-C (UV-C) irradiation. The effect of UV-C intensity, pH, treatment time, solvents and the exposure of food components were evaluated. After treated by UV-C irradiation at 3500 µW/cm2 for 90 min, AOH samples in methanol, aqueous solution and solid state were degraded by 89.1%, 72.9% and 53.2%, respectively, while the degradation percentages of AME were 86.6%, 50.1% and 11.1%, respectively. Increasing irradiation intensity and prolonging irradiation time could significantly facilitate the degradation of AOH and AME. An alkaline environment (pH = 11) was more conducive to the degradation of toxins. In addition, 2.5 mg mL-1 citric acid or malic acid increased the photodegradation of AOH and AME to 94.6% and 95.3%, 93.2% and 70.5%, respectively. However, protein, polyphenols and vitamin C exerted inhibitory effects on the degradation, while 10% glucose or sucrose reduced the photodegradation of AOH and AME to 65.9% and 40.3%. UV-C treatment could effectively reduce the content of AOH and AME, with the highest efficiency achieved in methanol and alkaline environment. By contrast, UV-C irradiation is more effective in degrading toxins in some liquid foods rich in organic acids but lacking in protein. The utilization of UV-C radiation appears to be a potentially useful approach for decreasing the underlying risk of Alternaria mycotoxin contamination in foods.

Simultaneous Measurement of Temperature and Pressure Based on Fabry-Perot Interferometry for Marine Monitoring.

The temperature and pressure of seawater are of great importance to investigate the environmental evolution for the research of ocean science. With this regard, we proposed and experimentally demonstrated a seawater temperature and pressure sensor realized by a polyimide (PI) tube-based Fabry-Perot interferometer (FPI) together with a fiber Bragg grating (FBG). Benefiting from the higher thermo-optical coefficient and larger elasticity of polymer than the fused silica fiber, the sensitivity of the sensor is largely improved. The FBG is used to compensate the cross effect of the temperature. The measured temperature and pressure sensitivities of the sensor are 18.910 nm/°C and -35.605 nm/MPa, respectively. Furthermore, the temperature and pressure information measured by the sensor can be achieved simultaneously using the sensitivity matrix method. In addition, the proposed sensor has advantages of easy fabrication, compact size, as well as capability of multiplexing and long-distance measurement, making it competitive and promising during the marine monitoring.

Simultaneous measurement of salinity and temperature using a Sagnac interferometer based on concatenated polarization-maintaining fiber tapers.

A Sagnac loop interferometer based on concatenated polarization-maintaining fiber (PMF) tapers is proposed for simultaneous measurement of seawater salinity and temperature. The influences of the distance between the PMF tapers as well as fiber taper diameter on sensor performance have been investigated. Experimental results indicate that the fabricated sensor with a distance of 3 cm between adjacent fiber tapers possesses the salinity and temperature sensitivities of 0.367 nm/% and -0.728nm/∘C, respectively, and the taper waist diameter of 20 µm would help to improve salinity sensitivity in comparison with a sensor of 30 µm in diameter. The proposed Sagnac loop interferometer based on concatenated PMF tapers is expected to find potential applications in the measurement of seawater salinity.

Protection of Nanostructures-Integrated Microneedle Biosensor Using Dissolvable Polymer Coating.

Real-time transdermal biosensing provides a direct route to quantify biomarkers or physiological signals of local tissues. Although microneedles (MNs) present a mini-invasive transdermal technique, integration of MNs with advanced nanostructures to enhance sensing functionalities has rarely been achieved. This is largely due to the fact that nanostructures present on MNs surface could be easily destructed due to friction during skin insertion. In this work, we reported a dissolvable polymer-coating technique to protect nanostructures-integrated MNs from mechanical destruction during MNs insertion. After penetration into the skin, the polymer could readily dissolve by interstitial fluids so that the superficial nanostructures on MNs could be re-exposed for sensing purpose. To demonstrate this technique, metallic and resin MNs decorated with vertical ZnO nanowires (vNWs) were employed as an example. Dissolvable poly(vinyl pyrrolidone) was spray-coated on the vNW-MNs surface as a protective layer, which effectively protected the superficial ZnO NWs when MNs penetrated the skin. Transdermal biosensing of H2O2 biomarker in skin tissue using the polymer-protecting MNs sensor was demonstrated both ex vivo and in vivo. The results indicated that polymer coating successfully preserved the sensing functionalities of the MNs sensor after inserting into the skin, whereas the sensitivity of the MN sensor without a coating protection was significantly compromised by 3-folds. This work provided unique opportunities of protecting functional nanomodulus on MNs surface for minimally invasive transdermal biosensing.