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The use of organochlorine and organophosphorus pesticides has been prohibited due to their highly toxicity. In recent years, pyrethroids (PYRs) have been widely used in agricultural production and the environment due to their high efficiency and stability, but the residual hazards caused by their frequent use have become increasingly prominent. 3-Phenoxybenzoic acid (3-PBA) is one of the major metabolites of PYRs, which is an environmental estrogen with great potential harms. Pesticide residues have seriously affected people’s production and life, which has attracted extensive attention from researchers. PYRs and 3-PBA degrading bacteria have been widely reported, and microbial and enzymatic degradation is recognized as an effective method for reducing or removing pesticide residues from agricultural products and the environment. The continuous development of genetic engineering and molecular biology technology provides a new way to explore methods for reducing pesticide residues. In this article, we summarize the basic properties and residual hazards of PYRs and 3-PBA, and we review the current status of PYRs residues in agricultural products and the environment as well as recent progress in research on the modes of microbial metabolism and the mechanisms of microbial adsorption and degradation of PYRs. Moreover, we give an outlook on enzymes degrading PYRs and their genetic engineering in order to provide a reference for solving the problem of pesticide residues in agricultural products and the environment.

ObjectiveTo establish a culture-dependent rapid detection method for gas-producing spoilage bacteria in vinegar.MethodsOne kind of medium was screened out from six candidate media and modified. Then its specificity， accuracy， and sensitivity were determined， on which a detection method was proposed. This method was subsequently applied to assess heat sterilization conditions and preservative concentrations for vinegar products and to verify the detection effectiveness of vinegar products.ResultsA modified MRS medium that could specifically detect gas-producing spoilage bacteria in vinegar samples was proposed， with which negative results were obtained targeting at other 12 spoilage bacteria isolated from vinegar. The established method was adopted to examine 75 unknown vinegar samples and plastic bottle incubation method was used as control. Consistent results were obtained using both methods， however the detection rate of established method was 3-5 times faster than control， with a detection limit （initial bacterial count） ranging from 1 CFU to 10 CFU. The larger bacterial load is， the shorter detection time would be. And it will take only 1-2 d for high-contamination vinegar samples. Results also showed that sterilization at 75-85 ℃ for 5-15 min could effectively kill the gas-producing spoilage bacteria that is recalcitrant to common preservatives within their maximum allowable concentrations. The verification was in agreement with the actual situation.ConclusionThe constructed method features fast， specific， accurate， and sensitive. This study sheds light on detection and comprehensive control of gas-producing spoilage bacteria for vinegar enterprises.

Phenolic acid decarboxylase (PAD) (lyase, EC 4.1.1.102) catalyzes the conversion of phenolic acids such as coumaric acid, ferulic acid, caffeic acid, and glucosic acid that are widely distributed in plants into 4-vinyl derivatives. 4-Vinyl derivatives are not only high-grade fragrances, but also key precursors for the synthesis of other spices such as vanillin. Food spices are mainly chemically synthesized in the current market. By contrast, the biosynthesis method, which is characterized by single precursor substances, mild conditions and environmental friendliness, has broad application prospects, and biosynthesized spices are regarded as being equivalent to natural products. Therefore, using PAD for the biosynthesis of 4-vinyl derivatives is of great significance to supplementing the production pathway of this type of fragrance. In this article, PAD derived from microorganisms are summarized from five aspects: origins, molecular structure, catalytic mechanism and structure-function correlation, catalytic properties, and techniques to improve the catalytic efficiency.

Salivary gland acinar cells are severely depleted after radiotherapy for head and neck cancer, leading to loss of saliva and extensive oro-digestive complications. With no regenerative therapies available, organ dysfunction is irreversible. Here, using the adult murine system, we demonstrate that radiation-damaged salivary glands can be functionally regenerated via sustained delivery of the neurogenic muscarinic receptor agonist cevimeline. We show that endogenous gland repair coincides with increased nerve activity and acinar cell division that is limited to the first week after radiation, with extensive acinar cell degeneration, dysfunction, and cholinergic denervation occurring thereafter. However, we found that mimicking cholinergic muscarinic input via sustained local delivery of a cevimeline-alginate hydrogel was sufficient to regenerate innervated acini and retain physiological saliva secretion at nonirradiated levels over the long term (>3 months). Thus, we reveal a previously unknown regenerative approach for restoring epithelial organ structure and function that has extensive implications for human patients.

Pyrethroids (PYRs) are widely used as pesticides due to low toxicity and high efficacy; however, PYRs residues have caused increasingly serious environmental and food safety problems. 3-Phenoxybenzoic acid (3-PBA), one of the major intermediate degradation products of PYRs, is more stable and toxic than the parent pesticides, and its residue can further aggravate environmental and agricultural product pollution. In recent years, filamentous fungal degradation of PYRs and 3-PBA has been reported, and research on this topic mainly focuses on strain screening, degradation characteristics, degradation pathways and localization of degradation enzymes. Unfortunately, key enzymes and their encoding genes involved in the degradation process are rarely reported. With the development of sequencing technology, molecular biology technology has provided a new strategy to mine PYR-degrading enzymes and their encoding genes in filamentous fungi. In this article, the basic properties, residues status and hazards of PYRs and 3-PBA are described. The filamentous fungi capable of degrading PYRs and 3-PBA, and their degradation pathways and degrading enzymes are reviewed. In addition, future prospects for the development of methods for screening and verification of degrading enzymes and their encoding genes are discussed. We expect that this review will provide a theoretical basis for understanding the degradation pathways and mechanisms of PYRs and 3-PBA by filamentous fungi and provide a reference for reducing residual pesticides in the environment and agricultural products.

Mitochondrial dysfunction is strongly implicated in neurodegenerative diseases including age-related macular degeneration (AMD), which causes irreversible blindness in over 50 million older adults worldwide. A key site of insult in AMD is the retinal pigment epithelium (RPE), a monolayer of postmitotic polarized cells that performs essential functions for photoreceptor health and vision. Recent studies from our group and others have identified several features of mitochondrial dysfunction in AMD including mitochondrial fragmentation and bioenergetic defects. While these studies provide valuable insight at fixed points in time, high-resolution, high-speed live imaging is essential for following mitochondrial injury in real time and identifying disease mechanisms. Here, we demonstrate the advantages of live imaging to investigate RPE mitochondrial dynamics in cell-based and mouse models. We show that mitochondria in the RPE form extensive networks that are destroyed by fixation and discuss important live imaging considerations that can interfere with accurate evaluation of mitochondrial integrity such as RPE differentiation status and acquisition parameters. Our data demonstrate that RPE mitochondria show localized heterogeneities in membrane potential and ATP production that could reflect focal changes in metabolism and oxidative stress. Contacts between the mitochondria and organelles such as the ER and lysosomes mediate calcium flux and mitochondrial fission. Live imaging of mouse RPE flatmounts revealed a striking loss of mitochondrial integrity in albino mouse RPE compared to pigmented mice that could have significant functional consequences for cellular metabolism. Our studies lay a framework to guide experimental design and selection of model systems for evaluating mitochondrial health and function in the RPE.

To solve the problem of incomplete cleaning of dust filter cartridge, the effect of the installation of diffuser and venture-tube on the pulsed-jet performance for dust cleaning filter cartridge was experimentally investigated. The effects of the jet distance on the pulse-jet pressure, the pulsed-jet intensity and uniformity were analyzed. The evolution of the filtration resistance during the stages of dust filtration and cleaning operation were compared. The results show that both diffuser and venture-tube could promote the pulse jet to expand and achieve a more uniform jet flow, but the combination of the diffuser and venture-tube would increase the airflow resistance, resulting in a lower pulsed-jet pressure. The pulsed-jet intensity increased first and then decreased with the jet distance under the conditions of common jet, the diffuser or the venture-tube installed only. When the jet distance was lower than 200 mm, the addition of diffuser and venture-tube alone or in combination is beneficial to improve the uniformity of injection. The best performance was achieved under the condition of 100 mm jet distance and the diffuser install only, with filtration period 1.3 times longer than that under the common pulse jet cleaning condition.