Three new neoclerodane diterpenoids (1-3), two new steroids (4-5), one new monoterpene (6), one new derivative of benzaldehyde (7) and one new iridoid glycoside (8), along with 19 known phenolic compounds, were isolated from Clerodendrum trichotomum. Their structures were established by a combination of detailed spectroscopic analyses (1D and 2D NMR) and high resolution electrospray ionization mass spectroscopy (HRESIMS). The isolated compounds were screened on α-glucosidase inhibitory and the peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist activities, and the results showed that three phenylethanoid glycosides, verbascoside (9), leucosceptoside a (10), and isoacteoside (13), and two flavonoids, apigenin (22) and luteolin (26) showed potent inhibitory effects against α-glucosidase, with IC50 values in the range from 15 to 700 μM. In addition, four flavonoids apigenin 7-O-β-D-glucuronide (19), apigenin (22), luteolin (26), and quercetin (27) exhibited significant PPAR-γ agonistic activities with EC50 values in the range 2.3-24.9 μM.

In 2020, Alternaria leaf blight and spot disease was first observed on Aloe barbadensis in Beijing, China. Samples of diseased leaves of A. barbadensis showing blight and spot symptoms (dark brown necrotic, sunken, and emerged lesions) were collected and identified as Alternaria isolates. The fungal colony was olive green, while conidia were brown, obclavate and measured from 13.4 to 34.2 x 7.5-11.8 mu m (length x width) on average. Genomic DNA extraction was performed by multi-locus sequence analysis and the pathogen was identified as Alternaria tenuissima. The pathogenicity test confirmed A. tenuissima's ability to infect A. barbadensis and cause typical leaf blight and spot symptoms, with subsequent re-isolation. This is the first report of leaf blight and leaf spot on A. barbadensis caused by A. tenuissima in Beijing, China. Due to the medicinal importance of A. barbadensis worldwide, studying A. tenuissima induced leaf blight and spot is imperative.

Ficus benghalensis L. belongs to the family Moraceae, native to Asia and commonly known as Banyan. It has been identified as an important medicinal tree due to its antioxidant, anti-diabetic, and anti-inflammatory properties (Singh et al., 2009; Thite et al., 2014). In March 2021, leaf spots were observed on Banyan trees in the Kharian forest zone, District Gujrat, Punjab Province, Pakistan. Initial symptoms on leaves were irregular, water-soaked, and light brown lesions. The lesions turned dark brown at the centre, and the margins gradually turned yellow. The average size of lesions was 12 to 20 × 8 to 13 mm. The lesions coalesced and produced necrotic areas on the leaf (Figure 1). Samples (n=34) were collected based on symptoms and infected leaf segments were excised into small pieces (10-20 mm), surface disinfected with 1% NaClO for 10 seconds and rinsed three times with sterilized distilled water (SDW). Ten pieces/sample were mashed and soaked in 1.5 ml SDW to obtain a suspension. Later, 10 µL of the suspension was streaked on Nutrient agar (NA) and King's B medium (KBM) and incubated for 72 h at 30°C. After 72 h bacterial colonies appeared on NA and KBM medium. Each colony was re-streaked for three times to obtain the purified colonies. Morphological and biochemical characteristics of isolated bacterial cultures were performed by following the method of Schaad et al. (2001). Bacterial colonies appeared pale yellow to creamy, smooth, and circular with undulated margins on both NA and KBM medium. The colonies produced a fluorescent blue colour on KBM under the UV light. Isolated bacterial cultures were positive for oxidase, negative for levan production and arginine dihydrolase. Based on these characteristics, the pathogen was identified as Pseudomonas species. For molecular identification, 16S rRNA and rpoB genes were amplified and sequenced using the following primers: 27F/1492R (Lane, 1991) and LAPS/LAPS27 (Ait Tayeb et al. 2005), respectively. All the isolates were identified as P. cichorii after BLASTn analysis. The sequences of isolate BLS-01 obtained in this study were deposited in GenBank with accession No. OK397593 for 16S rRNA and OK423684 for rpoB exhibiting 100 % similarity with P. cichorii Accession No. MK356431 for 16S rRNA and JQ267563 for rpoB. A pathogenicity test was performed on healthy Banyan seedlings to fulfil Koch's postulates. Leaves from seedling plants were inoculated with 3 mL of BLS-01 suspension (108 CFU/ml) by spraying the inoculum on leaves using a sterilized spray bottle. The leaves sprayed with sterilized distilled water served as control (Figure 2). The experiment was performed three times following the same protocol as described above. Symptoms that appeared on inoculated leaves after 7-10 days were similar to the symptoms observed on original infected Banyan tree leaves in the forest zone. Control leaves remained asymptomatic during the whole experiment. The pathogen from the artificial infected leaves was re-isolated and identified as P. cichorii based on morphological, biochemical, and molecular characteristics. To our knowledge, this is the first report of leaf spot of F. benghalensis caused by P. cichorii in Pakistan.

AIMS The present study aimed to isolate a potential antagonist Bacillus sp. and evaluate its capacity for controlling pathogenic Vibrio parahaemolyticus in aquaculture. METHODS AND RESULTS Strain JK08, which showed inhibitory activity against V. parahaemolyticus VP02r, was isolated from a Penaeus vannamei pond. Based on morphological, physiological, and biochemical characteristics and phylogenetic analysis, strain JK08 was identified as Bacillus sp. Through culture condition optimization, the maximal inhibition zone diameter (18.19 ± 0.16 mm) was observed when strain JK08 was cultivated at a temperature of 30°C, pH of 7, and salinity of 20‰ in Luria-Bertani broth for 24 h. The inhibition zone against V. parahaemolyticus VP02r of strain JK08 (approximately 7 μg, in mass of crude antimicrobial substance, per tablet) was larger than those (14-18 mm in diameter) of several commercial antibiotics (10 μg per tablet) in the in vitro antagonism assay. Liquid chromatography-tandem mass spectrometry analysis results indicated the presence of three families of lipopeptides in the antimicrobial substance: surfactin (C12-C17), iturin A (C14-C17), and fengycin A (C14-C17) and B (C17), which might be the key components contributing to the antagonistic activity of Bacillus sp. strain JK08. CONCLUSIONS Strain JK08, which is capable of producing antibacterial lipopeptides, shows effective antagonistic activity against V. parahaemolyticus VP02r, implying its promising potential for V. parahaemolyticus control in aquaculture.

The use of synthetic fungicides against postharvest Alternaria rot adversely affects human health and the environment. In this study, as a safe alternative to fungicides, Bacillus subtilis strain Y17B isolated from soil exhibited significant antifungal activity against Alternaria alternata. Y17B was identified as B. subtilis based on phenotypic identification and 16S rRNA sequence analysis. To reveal the antimicrobial activity of this strain, a PCR-based study detected the presence of antifungal lipopeptide (LP) biosynthetic genes from genomic DNA. UPLC Q TOF mass spectrometry analysis detected the LPs surfactin (m/z 994.64, 1022.68, and 1026.62), iturin (m/z 1043.56), and fengycin (m/z 1491.85) in the extracted LP crude of B. subtilis Y17B. In vitro antagonistic study demonstrated the efficiency of LPs in inhibiting A. alternata growth. Microscopy (SEM and TEM) studies showed the alteration of the morphology of A. alternata in the interaction with LPs. In vivo test results revealed the efficiency of LPs in reducing the growth of the A. alternata pathogen. The overall results highlight the biocontrol potential of LPs produced by B. subtilis Y17B as an effective biological control agent against A. alternata fruit rot of cherry.

Ochratoxin A (OTA) is a highly toxic and carcinogenic mycotoxin whose toxicity includes hepatotoxicity, genotoxicity, cytotoxicity and immunotoxicity. Recently, there have been many studies on OTA biosynthetic gene clusters. AoOTAbZIP (also known as otaR1) basic region/leucine zipper (bZIP)-specific gene that controls the expression levels of 4 biosynthetic genes in the OTA biosynthetic pathway, bZIP gene is known to be involved in the regulation of mycotoxin biosynthesis by various environmental factors in eukaryotes. This study explored the regulation of OTA biosynthesis in Aspergillus ochraceus under AoOTAbZIP-mediated water activity stress. High water activity (0.96 AW) was beneficial to the growth of A. ochraceus, and moderate water activity conditions of 0.91 AW has a stress effect on A. ochraceus, among them the growth of the mutant strain was better than that of the wild type. The mutant did not produce OTA at any condition. Wild type toxin production and expression levels of the OTA biosynthetic genes decreased under both high water activity (0.96 AW) and moderate water activity (0.91 AW), indicating that the toxin production of A. ochraceus was also affected by this water activity degree, moreover, the expression levels of the biosynthetic genes in the mutant strain were inhibited to extremely low levels compared to the wild type. The pathogenicity experiments revealed that pears infected with WT and ΔAoOTAbZIP mutant strains showed no significant differences, indicating that the deletion of the AoOTAbZIP gene has no significant effect on the pathogenicity of A. ochraceus.

In order to strategy more suitable campus-based coronavirus disease 2019 prevention programs for undergraduate students, it is critical to identify discrepancies in knowledge of COVID-19 prevention among students from different campuses in China.The present study examined the difference in preventive knowledge about COVID-19 pandemic in undergraduate students from two cities of Greater Bay Area (GBA), Macao Special Administrative Region (SAR), which had very few cases of COVID-19 patients, and Zhuhai, which is borders Macao SAR.In August 2020, two cohorts of undergraduate students from universities in Macao (n=977) and Zhuhai (n=2818) were recruited for online, self-rating questionnaire to gain information about their knowledge in COVID-19 prevention.Macao and Zhuhai students had similar correct rates in terms of heat inactivation conditions of COVID-19 virus, SARS-CoV-2, (76.8% vs. 76.9%,P=0.950), etiquette when coughing and sneezing (75.9% vs. 75.0%,P=0.562), and use of disposable masks (92.2% vs. 90.6%,P=0.126).However, students from Macao had significantly higher rates in correct use of disinfectants against SARS-CoV-2 (24.6% vs. 17.5%,P<0.001) and in the route of transmission of SARS-CoV-2 (84.5% vs. 79.6%,P<0.001) than those from Zhuhai.In conclusion, the knowledge level of COVID-19 prevention differs among undergraduate students from Macau and Zhuhai, which warrants an appropriate region-specific health education strategie for COVID-19 prevention.