Assessment of bacteriophage vB_Pd_PDCC-1 on bacterial dynamics during ontogenetic development of the longfin yellowtail (Seriola rivoliana).

The Seriola genus includes species of worldwide commercial importance due to its rapid growth and easy adaptability to confinement conditions. However, like other fish species, large mortalities occur during their early life stages, where the main problems are caused by opportunistic bacteria. Disease control strategies are thus urgently needed. The present study aimed to evaluate the efficacy of phage vB_Pd_PDCC-1 during the early development of longfin yellowtail (Seriola rivoliana), as well as its effect on microbial communities. This broad-host-range phage was added to the culture every 3 days starting from the egg-stage until 12 days after hatching (DAH) at a concentration of 1.41×1010 plaque-forming units (PFU) per mL and at a multiplicity of infection (MOI) of 1. The results showed positive effects (p<0.05) on egg hatching, survival, growth, and pigmentation area in treated larvae. Moreover, high-throughput sequencing analysis of 16S rRNA genes showed that phage administration did not produce significant changes (p>0.05) in the composition and structure of the associated microbiota. However, sequences affiliated to the Gammaproteobacteria class were displaced by those belonging to the Alphaproteobacteria class over time regardless of the treatment received. At the family level, there was a decrease in Rhodobacteraceae, Pseudoalteromonadaceae, and Flavobacteriaceae in both groups over time. To our best knowledge, this study represents the first attempt to evaluate the effect of a phage as a biological control agent during ontogenetic development of longfin yellowtail larvae. KEY POINTS: • Phages can be used against proliferation of Vibrio in fish cultures. • Seriola includes several important commercial fish species due to its rapid growth. • Phages do not cause significant changes in the associated microbiota.

Early Optimization Stages of Agave lechuguilla Bagasse Processing toward Biorefinement: Drying Procedure and Enzymatic Hydrolysis for Flavonoid Extraction.

Agave lechuguilla agro-waste is a promising renewable material for biorefining purposes. The procurement of added-value co-products, such as bioactive phytochemicals, is required to improve bioprocesses and promote the bio-based economy of the productive areas of Mexico. In this study, we aimed to evaluate the effect of post-harvest management and enzymatic pretreatment as the first stages of the A. lechuguilla valorization process. Four drying methods were compared, and enzymatic hydrolysis was optimized to obtain a flavonoid-enriched extract applying ultrasound-assisted extraction. In both experiments, the total phenolic (TPC) and flavonoid (TFC) contents, HPLC-UV flavonoid profiles, and radical scavenging capacity (DPPH) were considered as response variables. The results demonstrated that light exposure during the drying process particularly affected the flavonoid content, whereas oven-dehydration at 40 °C in the dark preserved the flavonoid diversity and antioxidant functionality of the extracts. Flavonoid glycoside recovery, particularly anthocyanidins, was 1.5-1.4-fold enhanced by enzymatic hydrolysis using the commercial mix Ultraflo© under optimized conditions (pH 4, 40 °C, 180 rpm, and 2.5 h) compared to the unpretreated biomass. The extraction of flavonoids from A. lechuguilla bagasse can be carried out using a scalable drying method and enzymatic pretreatment. This study confirmed the potential of this agro-waste as a source of marketable natural products.

Enhanced Antioxidant, Antifungal, and Herbicidal Activities through Bioconversion of Diosgenin by Yarrowia lipolytica P01a.

This study explores the bioconversion of diosgenin by Yarrowia lipolytica P01a, focusing on enhancing the antioxidant, antifungal, and herbicidal activities of the resulting extracts. The bioconversion process, involving glycosylation and hydroxylation, produced significant amounts of protodioscin and soyasaponin I. The extracts showed superior antioxidant activity, with up to 97.02% inhibition of ABTS· radicals and 33.30% inhibition of DPPH· radicals at 1000 mg L-1 of diosgenin. Antifungal assays revealed strong inhibitory effects against Botrytis cinerea, Alternaria sp., and Aspergillus niger, with maximum inhibition rates of 67.34%, 35.63%, and 65.53%, respectively. Additionally, the herbicidal activity of the bioconverted extracts was comparable to commercial herbicides, achieving 100% inhibition of seed germination in both monocotyledonous and dicotyledonous plants. These findings suggest that the Y. lipolytica P01a-mediated bioconversion of diosgenin could provide a sustainable and eco-friendly alternative for developing natural biofungicides and bioherbicides.

Hypolipidemic and Antioxidant Effects of Guishe Extract from Agave lechuguilla, a Mexican Plant with Biotechnological Potential, on Streptozotocin-Induced Diabetic Male Rats.

In the present study, we used a by-product from Agave lechuguilla (guishe) to test its antidiabetic effect, hypolipidemic activity, and capacity to mitigate the oxidative stress in kidney mitochondria from streptozotocin-induced diabetic rats. Orally, a crude aqueous extract from lyophilized guishe was administered over 5 weeks at different doses. Blood glucose and body weight were monitored. Also, blood chemistry, bilirubin, and alanine aminotransferase were assayed. Furthermore, the activity of catalase, thiobarbituric acid reactive species, mitochondrial superoxide dismutase, glutathione and glutathione peroxidase were determined in isolated kidney mitochondria. Our results show that guishe extracts have no antidiabetic properties at any dose. Nevertheless, it was able to diminish serum triglyceride levels and regulate the oxidative stress observed in isolated kidney mitochondria. These observations indicate that the aqueous extract from guishe can be used to treat abnormalities in serum lipids, as a hypolipidemic, and mitigate the oxidative stress, as an antioxidant, occurring during diabetes.

Transcriptome-based metabolic profiling of flavonoids in Agave lechuguilla waste biomass.

Agave lechuguilla is one of the most abundant species in arid and semiarid regions of Mexico, and is used to extract fiber. However, 85 % of the harvested plant material is discarded. Previous bioprospecting studies of the waste biomass suggest the presence of bioactive compounds, although the extraction process limited metabolite characterization. This work achieved flavonoid profiling of A. lechuguilla in both processed and non-processed leaf tissues using transcriptomic analysis. Functional annotation of the first de novo transcriptome of A. lechuguilla (255.7 Mbp) allowed identifying genes coding for 33 enzymes and 8 transcription factors involved in flavonoid biosynthesis. The flavonoid metabolic pathway was mostly elucidated by HPLC-MS/MS screening of alcoholic extracts. Key genes of flavonoid synthesis were higher expressed in processed leaf tissues than in non-processed leaves, suggesting a high content of flavonoids and glycoside derivatives in the waste biomass. Targeted HPLC-UV-MS analyses confirmed the concentration of isorhamnetin (1251.96 µg), flavanone (291.51 µg), hesperidin (34.23 µg), delphinidin (24.23 µg), quercetin (15.57 µg), kaempferol (13.71 µg), cyanidin (12.32 µg), apigenin (9.70 µg) and catechin (7.91 µg) per gram of dry residue. Transcriptomic and biochemical profiling concur in the potential of lechuguilla by-products with a wide range of applications in agriculture, feed, food, cosmetics, and pharmaceutical industries.

High Throughput Profiling of Flavonoid Abundance in Agave lechuguilla Residue-Valorizing under Explored Mexican Plant.

Agave lechuguilla waste biomass (guishe) is an undervalued abundant plant material with natural active compounds such as flavonoids. Hence, the search and conservation of flavonoids through the different productive areas have to be studied to promote the use of this agro-residue for industrial purposes. In this work, we compared the proportion of total flavonoid content (TFC) among the total polyphenolics (TPC) and described the variation of specific flavonoid profiles (HPLC-UV-MS/MS) of guishe from three locations. Descriptive environmental analysis, using remote sensing, was used to understand the phytochemical variability among the productive regions. Furthermore, the effect of extractive solvent (ethanol and methanol) and storage conditions on specific flavonoid recovery were evaluated. The highest TPC (16.46 ± 1.09 GAE/g) was observed in the guishe from region 1, which also had a lower normalized difference water index (NDWI) and lower normalized difference vegetation index (NDVI). In contrast, the TFC was similar in the agro-residue from the three studied areas, suggesting that TFC is not affected by the studied environmental features. The highest TFC was found in the ethanolic extracts (6.32 ± 1.66 QE/g) compared to the methanolic extracts (3.81 ± 1.14 QE/g). Additionally, the highest diversity in flavonoids was found in the ethanolic extract of guishe from region 3, which presented an intermedia NDWI and a lower NDVI. Despite the geo-climatic induced variations of the phytochemical profiles, the results confirm that guishe is a valuable raw material in terms of its flavonoid-enriched bioactive extracts. Additionally, the bioactive flavonoids remain stable when the conditioned agro-residue was hermetically stored at room temperature in the dark for nine months. Finally, the results enabled the establishment of both agro-ecological and biotechnological implications.

The Streptomyces coelicolor genome encodes a type I ribosome-inactivating protein.

Ribosome-inactivating proteins (RIPs) are cytotoxic N-glycosidases identified in numerous plants, but also constitute a subunit of the bacterial Shiga toxin. Classification of plant RIPs is based on the absence (type I) or presence (type II) of an additional lectin module. In Shiga toxin, sugar binding is mediated by a distinct RIP-associated homopentamer. In the genome of two actinomycetes, we identified RIP-like proteins that resemble plant type I RIPs rather than the RIP subunit (StxA) of Shiga toxin. Some representatives of ß- and γ-proteobacteria also contain genes encoding RIP-like proteins, but these are homologous to StxA. Here, we describe the isolation and initial characterization of the RIP-like gene product SCO7092 (RIPsc) from the Gram-positive soil bacterium Streptomyces coelicolor. The ripsc gene was expressed in Escherichia coli as a recombinant protein of about 30 kDa, and displayed the characteristic N-glycosidase activity causing specific rRNA depurination. In Streptomyces lividans and E. coli, RIPsc overproduction resulted in a dramatic decrease in the growth rate. In addition, intracellular production was deleterious for Saccharomyces cerevisiae. However, when applied externally to microbial cells, purified RIPsc did not display antibacterial or antifungal activity, suggesting that it cannot enter these cells. In a cell-free system, however, purified S. coelicolor RIPsc protein displayed strong inhibitory activity towards protein translation.

Improving rifamycin production in Amycolatopsis mediterranei by expressing a Vitreoscilla hemoglobin (vhb) gene fused to a cytochrome P450 monooxygenase domain.

Expression of the vhb gene encoding hemoglobin from Vitreoscilla stercoraria in several organisms, clearly enhances oxygen-dependent product formation. In a previous work, we expressed the vhb gene that encodes hemoglobin from V. stercoraria in Amycolatopsis mediterranei, resulting in an increase (oxygen-dependent formation) in rifamycin B production. In the present work, we first confirm; by heterologous expression in Escherichia coli, that rif-orf5 from the rifamycin biosynthetic gene cluster, really encodes a cytochrome P450 enzyme, which is the key step for oxygen incorporation in the final biosynthetic product. Likewise, we fused rif-orf5 to the vhb gene, as part of a genetic engineering strategy. The fused genes were used to generate an Amycolatopsis mediterranei transformant (Msb-HbCYP5). Interestingly, the fermentation of Msb-HbCYP5 manifested 1.5-fold higher rifamicin B production than the transformant with only the hemoglobin gene, and 2.2-fold higher than the parental strain.

Antioxidant, anti-inflammatory and antinociceptive potential of Ternstroemia sylvatica Schltdl. & Cham.

OBJECTIVE: To evaluate the anti-inflammatory, analgesic, antioxidant and acute toxicity of extracts obtained from a successive extraction with solvents of ascending polarity [hexane, hex; chloroform, CHCl3 and ethanol (EtOH)] of Ternstroemia sylvatica Schltdl. & Cham. METHODS: The antioxidant potential was evaluated by 2,2 diphenyl-1-picrylhydrazyl, the ferric reducing/antioxidant power assays and by determining the total phenolic content. The anti-inflammatory and antinociceptive effects were evaluated using the in vivo croton oil-induced ear edema, phorbol 12-myristate 13-acetate induced ear edema, carrageenan-induced paw edema, acetic acid-induced writhing and formalin murine models. The acute toxicity was tested using the Lorke's method in mice. RESULTS: The EtOH extract was the most active for the antioxidant potential tests diphenyl-1-picrylhydrazyl (68.70% inhibition), ferric reducing/antioxidant power [(2431.30 ± 102.10) mmol Fe2+ and total polyphenols content (215.80 ± 8.50) meqAG/g]. The anti-inflammatory activity was evaluated by topical application of croton oil (2 mg/ear dose) where the EtOH extract showed the strongest activity compared to the control group (45.13% inhibition), whereas in the phorbol 12-myristate 13-acetate model, at the same dose, the CHCl3 extract showed the highest inhibition (42.88%). In the carrageenan induced edema model, the EtOH extract showed a stronger inhibition compared to indomethacin (56.34% and 50.70% at doses of 250 and 500 mg/kg of extract, respectively) during the first hour. Similarly, the same extract showed the highest analgesic activity (30.60% inhibition) in the acetic acid contortion assay, and in the formalin test it showed a greater effect with respect to the control group in both phases. CONCLUSIONS: Our work confirms the value of Ternstroemia sylvatica as an important anti-inflammatory and analgesic plant, whose mechanism seems to be associated to its antioxidant effects, and supports its uses in the Mexican traditional medicine.

Ribosome-inactivating proteins with an emphasis on bacterial RIPs and their potential medical applications.

Ribosome-inactivating proteins (RIPs) are toxic due to their N-glycosidase activity catalyzing depurination at the universally conserved α-sarcin loop of the 60S ribosomal subunit. In addition, RIPs have been shown to also have other enzymatic activities, including polynucleotide:adenosine glycosidase activity. RIPs are mainly produced by different plant species, but are additionally found in a number of bacteria, fungi, algae and some mammalian tissues. This review describes the occurrence of RIPs, with special emphasis on bacterial RIPs, including the Shiga toxin and RIP in Streptomyces coelicolor recently identified in S. coelicolor. The properties of RIPs, such as enzymatic activity and targeting specificity, and how their unique biological activity could be potentially turned into medical or agricultural tools to combat tumors, viruses and fungi, are highlighted.