The Na+ /Ca2+ antiporter slr0681 affects carotenoid production in Synechocystis sp. PCC 6803 under high-light stress.

BACKGROUND: Carotenoids play key roles in photosynthesis and are widely used in foods as natural pigments, antioxidants, and health-promoting compounds. Enhancing carotenoid production in microalgae via biotechnology has become an important area of research. RESULTS: We knocked out the Na+ /Ca2+ antiporter gene slr0681 in Synechocystis sp. PCC 6803 via homologous recombination and evaluated the effects on carotenoid production under normal (NL) and high-light (HL) conditions. On day 7 of NL treatment in calcium ion (Ca2+ )-free medium, the cell density of Δslr0681 decreased by 29% compared to the wild type (WT). After 8 days of HL treatment, the total carotenoid contents decreased by 35% in Δslr0681, and the contents of individual carotenoids were altered: myxoxanthophyll, echinenone, and ß-carotene contents increased by 10%, 50%, and 40%, respectively, while zeaxanthin contents decreased by ~40% in Δslr0681 versus the WT. The expression patterns of carotenoid metabolic pathway genes also differed: ipi expression increased by 1.2- to 8.5-fold, whereas crtO and crtR expression decreased by ~90% and 60%, respectively, in ∆slr0681 versus the WT. In addition, in ∆slr0681, the expression level of psaB (encoding a photosystem I structural protein) doubled, whereas the expression levels of the photosystem II genes psbA2 and psbD decreased by ~53% and 84%, respectively, compared to the WT. CONCLUSION: These findings suggest that slr0681 plays important roles in regulating carotenoid biosynthesis and structuring of the photosystems in Synechocystis sp. This study provides a theoretical basis for the genetic engineering of microalgae photosystems to increase their economic benefits and lays the foundation for developing microalgae germplasm resources with high carotenoid contents. © 2023 Society of Chemical Industry.

Arbuscular mycorrhizal fungi increased peanut (Arachis hypogaea L.) yield by changing the rhizosphere microbial community structure in saline-alkali soil.

Arbuscular mycorrhizal fungi (AMF) have demonstrated the potential to enhance the saline-alkali tolerance in plants. Nevertheless, the extent to which AMF can ameliorate the tolerance of salt-sensitive plants to alkaline conditions necessitates further investigation. The current study is primarily centered on elucidating the impact of AMF on the growth of the Huayu22 (H22) when cultivated in saline-alkaline soil. We leveraged DNA of rhizosphere microorganisms extracted from saline-alkali soil subjected to AMF treatment and conducted high-throughput sequencing encompassing 16S rRNA gene and ITS sequencing. Our findings from high-throughput sequencing unveiled Proteobacteria and Bacillus as the prevailing phylum and genus within the bacterial population, respectively. Likewise, the predominant fungal phylum and genus were identified as Ascomycota and Haematonectria. It is noteworthy that the relative abundance of Proteobacteria, Actinobacteria, Chloroflexi, Bacteroidetes, and Ascomycota exhibited significant increments subsequent to AMF inoculation. Our investigation into soil enzyme activity revealed a remarkable surge post-AMF inoculation. Notably, the amounts of pathogen growth inhibitory enzymes and organic carbon degrading enzymes rise, as predicted by the putative roles of microbial communities. In saline-alkali soil, inoculation of AMF did boost the yield of H22. Notable improvements were observed in the weight of both 100 fruits and 100 grains, which increased by 20.02% and 22.30%, respectively. Conclusively, this study not only provides a theoretical framework but also furnishes empirical evidence supporting the utilization of AMF as a viable strategy for augmenting the yield of salt-sensitive plants grown in alkaline conditions.

Advanced treatment of secondary effluent from wastewater treatment plant by a newly isolated microalga Desmodesmus sp. SNN1.

Secondary effluents contain considerable amounts of nitrogen and phosphorous, which if dumped untreated can cause eutrophication of the receiving water bodies. Microalgae can remove these nutrients and other pollutants from the wastewater effluents and play an effective role in the secondary effluent treatment. In this study, six microalgae strains (SNN1, SNN2, SNN3, SNN4, SNS1, and SNS2) were isolated and screened from the water and mud of Yingxue Lake of Shandong Jianzhu University, and their efficiencies for the removal of COD, NH4 +-N, TN, and TP in the secondary effluent were assessed. By comparing the growth performances and nutrient removal ability of algal strains in domestic sewage, we found that SNN1 (identified and named as Desmodesmus sp. SNN1) has the highest efficiency for biomass accumulation and sewage purification. Hence, the algal strain SNN1 was selected for further screening and optimization experiments. The strain showed higher biomass yield and better nutrient removal rate when the pH of secondary effluent was 9.0 and the initial inoculum concentration (optical density at 680 nm) of algal strain was 0.4. After 12 days of treatment, the concentrations of COD, NH4 +-N, TN, and TP in the secondary effluent were 31.79, 0.008, 8.631, and 0.069 mg/L, respectively. Therefore, SNN1 with the removal rates of 52.69% (COD), 99.99% (NH4 +-N), 89.09% (TN), and 94.64% (TP) displayed its high potential in nutrient removal. In addition, it also yielded 5.30 mg/L of chlorophyll a and 168.33 mg/L of lipids. These results demonstrated that this strain exhibited an effective treatment capacity for secondary effluent and microalgal oil production. This study is helpful to provide a strategy for the resource utilization of secondary effluent and the conservation of freshwater resources required by microalgae culture.

First Record of Chaetomium globosum Causing Leaf Spot of Pomegranate in Pakistan.

Pomegranate (Punica granatum L.) is a non-climacteric and a favorite fruit of tropical, sub-tropical and arid regions of the world. During a survey in autumn 2019, leaf lesions were observed on plants (cv. Kandhari) in different orchards of Muzaffargarh (30°4'27.7572″ N, 71°11'4.7544″ E), a major pomegranate-producing region in Punjab Province. Disease incidence ranged from 17 to 20%. Leaf lesions were initially small (1 to 3 mm in diameter), round, purple or reddish-brown, scattered spots. At later stages, spots increased in size and the centers of mature lesions became dark red or black with fungal sporulation. To isolate the pathogen, samples of leaf (5 × 5 mm) were cut from the junction of diseased and healthy tissue, surface disinfected in 75% alcohol for 30 s, sterilized with 6% sodium hypochlorite for 3 min, washed with sterile distilled water three times, air dried in laminar flow hood, and cultured on potato dextrose agar (PDA). After one week of incubation at 25 ± 2°C with a 12-h photoperiod, fungal colonies developed, which were initially white and became pale yellow with olivaceous green mycelium after 20 days. On PDA, ascomata were olivaceous green, with a papillate ostiole, globose or ovoidal to obovoidal (155 to 220 × 120 to 240 µm, n=50). Terminal and lateral setae were abundant, brown, and tapering toward the tips (4 to 6 µm, n=50). Asci were greenish and lemon-shaped (6 to 8 × 9 to 13.5 µm, n=50). Ascospores were limoniform and olivaceous gray-brown (10 to 11.5 × 7 to 9 µm, n=50). These morphological characteristics were consistent with the morphology of Chaetomium globosum (Lan et al. 2011; Wang et al. 2016). Genomic DNA was extracted from two isolates and identification of the pathogen was confirmed by amplification and sequencing of the internal transcribed spacer region (ITS) and the partial translation elongation factor 1-α (TEF1) gene using ITS1/ITS4 (White et al. 1999) and EF1-983F/EF1-2218R primers (Wang et al. 2016), respectively. The sequences of the PCR products were deposited in GenBank with accession numbers MW522514, MW522352 (ITS), and MW530423, MW530424 (TEF1). BLAST results of the obtained sequences of the ITS and TEF1 genes revealed 100% (513/513 bp) and 99.78% (927/929 bp) similarity with those of C. globosum in GenBank (ITS: KX834823 and KT898637, and TEF1: MG812564 and KC485028). To confirm pathogenicity, inoculum was prepared by harvesting conidia from 10-day-old culture grown in PDA. The surface-disinfected (70% ethyl alcohol, 30 s) leaves of ten 1-year-old seedlings (cv. Kandhari) were sprayed with a spore suspension (1×106 conidia/ml). Leaves of ten seedlings sprayed with sterile distilled water served as controls. All seedlings were covered with plastic bags and placed in a greenhouse at 26°C with 12 h photoperiod. After eight days, symptoms on inoculated leaves were similar to those observed in the orchards; no symptoms were observed on controls. The fungus was reisolated from all symptomatic tissues. C. globosum has been reported on Punica granatum (Guo et al. 2015), Cannabis sativa (Chaffin et al. 2020) and Brassica oleracea (Zhu et al. 2020). This is the first report of C. globosum causing leaf spot on pomegranate in Pakistan. This finding suggests a potential threat to pomegranate production in Pakistan and further studies should focus on effective prevention and control practices of this disease.

The role of inflammatory markers following Ramadan Fasting.

OBJECTIVES: The aim of present study was to investigate the effect of fasting during Ramadan on plasma adiponectin and TNF-α levels. METHODS: This is a cross sectional study, conducted at Federal Urdu University of Arts, Science & Technology (FUUAST), Karachi, comprising a total of 55 (50%) females and 55 (50%) males whose ages ranged between 20 and 40 years, and fasted during Ramadan (June-July 2014) were enrolled in the study. Subjects were separated into normal weight, overweight and obese males and females. Anthropometric measurements and Fasting venous blood samples were taken at first and last (29th) day of Ramadan. Plasma adiponectin and TNF-alpha levels were assayed with ELISA kits. All values were calculated and presented as mean ± standard error of the mean (SEM) and by using analysis of variance (ANOVA) for repeated measures. P values < 0.05 were accepted as significant. RESULTS: Body mass index (BMI) (Kg/m2) in over-weight and obese male subjects exhibited considerable reduction (P<0.05; P<0.05), post Ramadan when compared to their respective pre Ramadan fasting weights. Noticeable and significant reduction was also observed in BMI of obese females (P<0.05). Post Ramadan Overweight Males (P<0.05) and Post Ramadan Obese Males (P<0.001) exhibited significantly elevated plasma adiponectin (µg/mL) values. While plasma adiponectin mean concentration of only obese females were significantly improved at last week of Ramadan (P<0.01). Fasting in Ramadan significantly decreased TNF-α (pg/mL) levels of post obese males and females than Pre-Ramadan-groups (P<0.05; P<0.01) respectively. CONCLUSION: The study reports of noticeable changes with Ramadan fasting resulting increase of plasma adiponectin and decrease of TNF-α levels as well as body weight. The study strongly suggests further investigations on larger sample sizes with possible association of dietary restrictions and weight loss on mechanism of enhanced adiponectin and reduced TNF-α in obese and overweight persons who fast on Ramadan pattern.

Domain III of Cry1Ac Is Critical to Binding and Toxicity against Soybean Looper (Chrysodeixis includens) but Not to Velvetbean Caterpillar (Anticarsia gemmatalis).

Insecticidal proteins Cry1Ac and Cry2Ac7 from the bacterium Bacillus thuringiensis (Bt) belong to the three-domain family of Bt toxins. Commercial transgenic soybean hybrids produce Cry1Ac to control the larvae of the soybean looper (Chrysodeixis includens) and the velvet bean caterpillar (Anticarsia gemmatalis). The specificity of Cry1Ac is determined by loops extending from domain II and regions of domain III in the three-dimensional structure of the toxin. In this study, we constructed a hybrid toxin (H1.2Ac) containing domains I and II of Cry1Ac and domain III of Cry2Ac7, in an attempt to obtain a protein with enhanced toxicity compared to parental toxins. Bioassays with H1.2Ac revealed toxicity against the larvae of A. gemmatalis but not against C. includens. Saturation binding assays with radiolabeled toxins and midgut brush border membrane vesicles demonstrated no specific H1.2Ac binding to C. includens, while binding in A. gemmatalis was specific and saturable. Results from competition binding assays supported the finding that Cry1Ac specificity against A. gemmatalis is mainly dictated by domain II. Taken together, these distinct interactions with binding sites may help explain the differential susceptibility to Cry1Ac in C. includens and A. gemmatalis, and guide the design of improved toxins against soybean pests.

Activity of Bacillus thuringiensis Cry1Ie2, Cry2Ac7, Vip3Aa11 and Cry7Ab3 proteins against Anticarsia gemmatalis, Chrysodeixis includens and Ceratoma trifurcata.

Transgenic soybean producing the Cry1Ac insecticidal protein from the bacterium Bacillus thuringiensis is used to control larvae of the velvetbean caterpillar (Anticarsia gemmatalis Hübner) and the soybean looper [Chrysodeixis includens (Walker)]. The main threat to the sustainability of this technology is the development of resistance, which could be delayed by using pyramiding of diverse Bt insecticidal genes. We report high activity of Cry2Ac7 and Vip3Aa11 but not Cry1Ie2 against larvae of A. gemmatalis and C. includens. In addition, we also report anti-feeding activity of Cry1Ie2 and Cry7Ab3 in adults of the bean leaf beetle [Ceratoma trifurcata (Foster)], an alternative pest of soybean.