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The use of high alkaline medium is a feasible way to provide carbon source and prevent biological contamination for the outdoor cultivation of alkaliphilic microalgae and cyanobacteria. A novel cyanobacterial strain was isolated from the open pond of a marine green alga (Picochlorum sp. SCSIO-45015, Sanya, Hainan) and identified as Cyanobacterium sp. SCSIO-45682. The effects of initial sodium bicarbonate (NaHCO3) concentrations on the growth and biochemical composition of Cyanobacterium sp. SCSIO-45682 were investigated. The results demonstrated that Cyanobacterium sp. SCSIO-45682 had good adaptation to 16.8 g/L NaHCO3 (the same concentration of NaHCO3 used in Zarrouk medium for Spirulina). Moreover, the yields of biomass, polysaccharide, chlorophyll a (chl a), and phycocyanin increased under high NaHCO3 concentrations. The maximum final biomass concentration of 2.5 g/L was observed at 8.4 g/L NaHCO3, while the highest intracellular total saccharide content of 49.2% of dry weight (DW) and exopolysaccharide (EPS) concentration of 93 mg/L were achieved at the NaHCO3 concentration of 16.8 g/L. The crude protein content declined under high NaHCO3 concentrations, which provide a possible explanation for the accumulation of polysaccharide. This study shows a good potential of alkaliphilic Cyanobacterium sp. SCSIO-45682 as a polysaccharide feedstock.

Neglected tropical diseases (NTDs) are a group of disabling infectious diseases that disproportionately affect middle- and low-income people in Africa and Latin America. Although progress has been made in controlling and/or eradicating these devastating infections, there is still an urgent need for new and accessible drugs. For several neglected tropical diseases there are no available drugs or drug resistance has emerged to the existing ones, limiting overall efficacy of the current treatments. Natural products have been a source of active metabolites against various targets through the years, with over half of the approved pharmaceuticals either inspired by or directly representing natural products. In this review, we present secondary metabolites isolated from marine sources that have demonstrated activity against these diseases and are promising candidates for drug development. Herein, we discuss 114 marine derived metabolites active against the WHO’s 2017 list of 20 NTDs. While not all these diseases have reported active marine natural products, we still describe these diseases and offer explanation as to why this rich source of bioactive metabolites has been omitted. With the development of new technologies in accessing new parts of the oceans, identifying novel chemistry or biological screening, the potential of marine natural products against NTDs has yet to be fully tapped into to.

Pseudorabies virus (PRV) infection can elicit nervous system disorders. Curcumin has been reported to have neuroprotective effects. However, whether curcumin can protect neurons against PRV infection and the underlying mechanisms remain unclear. In the present study, for the first time, the protective effects of curcumin against PRV-induced oxidative stress, apoptosis, and mitochondrial dysfunction in rat hippocampal neurons and the brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) pathway were investigated. Results indicated that PRV with a titer of 3.06 × 106 TCID50 (50% tissue culture infective dose) induced oxidative damage of hippocampal neurons 2 h post-infection and that 10 μM curcumin improved the viability of PRV-infected hippocampal neurons. Blocking the BDNF/TrkB pathway reversed the neuroprotective effects of curcumin, which were imparted by decreasing the PRV-induced upregulation of nitric oxide synthase expression, repressing the PRV-activated mitochondrial apoptotic pathway, and mitochondrial dysfunction. To conclude, curcumin exhibited a neuroprotective role against PRV infection by upregulating the BDNF/TrkB pathway. This study provides insight into the anti-PRV neuroprotective application of curcumin and the underlying mechanism in the prophylaxis and treatment of neurological disorders caused by PRV infection.

Here, we present a dual amplification strategy based on a duplex-specific nuclease and a hybridization chain reaction, which has been designed for the highly sensitive detection of miRNAs. In the first step, a loop amplification strategy based on a duplex-specific nuclease was employed to obtain a large number of ssDNA reporters that then act as initiators to trigger the next amplification step. The second step involves a hybridization chain reaction based on two hairpin DNAs denoted as H1 and H2. Doxorubicin-CdTe quantum dots, which function as detecting indicators that intercalated into the hybridization chain reaction products, lead to significantly amplified electrochemiluminescence signal readout. This dual amplification strategy enabled the sensitive detection of let-7d from 10 aM to 10 nM with a detection limit of 10 aM, and offered an excellent capacity to discriminate between microRNA family members. This assay therefore offers great potential applications in biomedical research and early clinical diagnosis.

Ethnopharmacological relevance Terminalia catappa L. (West Indian-Almond) is a medicinal plant used in traditional medicine for the treatment of infectious diseases. Moreover, various organic extracts prepared from this plant have been reported to exhibit antiplasmodial activity. Aim of the study The need for new antimalarials is still an urgency driven by the alarmingly high burden of malaria in endemic regions, with multitude of people dying annually. We have previously identified an endophytic fungus Aspergillus niger 58 harboured by T. catappa as having promising specialized secondary metabolites against the malaria parasites. In the present study, we report the antiplasmodial activity-guided chromatographic isolation of some metabolites secreted by this endophytic fungus. Materials and methods The SYBR Green I-based fluorescence microtiter plate assay was used to monitor the growth of Plasmodium falciparum parasites in culture in the presence and absence of inhibitors and results were validated by microscopic analysis of Giemsa-stained culture smears. Giemsa-stain microscopy was also used to study the cell cycle stage-specific action of selected fractions. Results The results revealed that the multidimensional purification of the crude extract (IC50: 4.03 μg/mL) provided RPHPLC F17 (IC50: 0.09 μg/mL) and RPHPLC F18 (IC50: 0.1 μg/mL) with activity against P. falciparum 3D7 (Pf3D7) strain. Moreover, both fractions at IC99 (0.5 μg/mL) exhibited multi-stages action by targeting all the three stages of the life cycle of blood-stage Pf3D7. Two compounds, flavasperone (1) and aurasperone A (2) were isolated, of which aurasperone A exhibited good potency against Pf3D7 (IC50: 4.17 μM) and P. falciparum INDO (PfINDO) (IC50: 3.08 μM). Conclusion Our study adds credence to the notion that endophytic extracts are potential storehouses for potent specialized secondary metabolites that can be harnessed to fight the malaria parasite and reduce the burden of this disease worldwide. An endophyte that can be cultured in laboratory with ability to secrete promising metabolites of medicinal value holds the promise of conserving Nature from the threat of annihilation of flora for medicinal purposes.

Algal β-glucans have received attention in recent years, but little is understood for the pattern and molecular mechanism of β-glucans accumulation in Chlorella, a more economically feasible microalga. In the present study, P-limited conditions were found to substantially inhibit the microalgal growth, reduce the lipid and protein production but induce the accumulation of β-glucans and total carbohydrate of Chlorella sorokiniana SCSIO 46784 during the early phase of growth. Comparative transcriptomics analysis of the microalga for the specific time point under P-limited and P-replete conditions identified key genes involved in β-glucans metabolism and revealed the probable molecular mechanism of the β-glucans accumulation. The significant up- and down-regulation of genes encoding β-glucans synthesis- and degradation-related enzymes coincided with a rapid increase in β-glucans production. The reduced synthesis of certain sugars (starch, sucrose, UDP-L-rhamnose, and UDP-sulfoquinovose) might provide more carbon precursors for β-glucans biosynthesis. The suppression of lipids (fatty acid, triacylglycerol, sulfoquinovosyl diacylglycerol, and monogalactosyldiacylglycerol) synthesis presumably shunted carbon flux toward carbohydrates and β-glucans biosynthesis. In addition, the down-regulation of multiple genes related to carbon fixation (CO2 concentrating mechanism and Calvin cycle) and central carbon metabolism (pentose phosphate pathway, glycolysis/gluconeogenesis, and tricarboxylic acid cycle) might contribute to the inferior growth of C. sorokiniana SCSIO 46784 under P-limited conditions. To our knowledge, this is the first report to reveal the metabolic insights into β-glucans in Chlorella. This study provides not only the useful information for understanding the biosynthesis and accumulation of β-glucans but also potential gene targets for genetic modification to improve the production of β-glucans in Chlorella.

The microalga, Nannochloropsis, is receiving increased attention for their potential application as a biodiesel feedstock and an aquaculture feed. Nannochloropsis cultured in different environments has been shown to possess different growth characteristics and the biochemical composition. The biochemical composition are critical as they dictate applicability and profitably of the species. In the present study, the outdoor productivity of Nannochloropsis oceanica SCS-1981 was investigated in a novel open pond that was completely powered by solar-electricity. Using this technique, the maximum cell density in the solar-powered open pond was 1.1 × 108 cell mL−1, with proteins the dominant biochemical component (53.1% of dry weight). Additionally, the microalga accumulated a high content of eicosapntemacnioc acid (EPA) comprising nearly 3% of the dry weight. Probiotics, such as Phaeodactylibacter, were present in the culture pond, which was a gram-negative bacteria that has been reported to have a positive effect on the absorption and immune system of cultured animal. The results of the study indicated that N. oceanica was suitable for aquiculture feeds. The productivity of biomass was 5.8 g m−2 d−1, which was similar to traditional raceway ponds. Considering that the solar-powered open pond requires no additional energy input, the costs of culturing can be significantly reduced. This culturing method is easy to work with and would be an easy technique to be used in the culturing of Nannochloropsis as living aquaculture feeds. The study will greatly promote the low-cost cultivation of microalgae for aquaculture feed purposes.

Two new 2-benzylpyridin-4-one containing metabolites, aspernigrins C (3) and D (4), together with six known compounds (1, 2, and 5-8), were isolated from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30. The structures of the new compounds were determined by NMR, MS, and optical rotation analyses. All the isolated compounds were evaluated for their inhibitory activities against infection with HIV-1 SF162 in TZM-bl cells. Malformin C (5) showed the strongest anti-HIV-1 activity with IC50 of 1.4±0.06μM (selectivity index, 11.4), meanwhile aspernigrin C (3) also exhibited potent activity with IC50 of 4.7±0.4μM (selectivity index, 7.5).

Aspernigrin C (Ia) and D (Ib) are isolated as new compounds together with six known compounds from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30.

Accurate lineage tracing is crucial to understanding of developmental and stem cell biology, but is particularly challenging for transient and highly dispersive cell-types like the neural crest (NC). The authors report in this article a new zebrafish transgenic line Tg(-4725sox10:Cre)ba74. This line expresses Cre under the control of a well-characterized portion of the sox10 promoter and, by crossing to a floxed-reporter line, the authors show in this article that expression in this line is consistent with those described for GFP reporter lines using the same promoter. Reporter expression is readily detected in patterns consistent with the early expression domains. Thus, the authors see all major groups (pigment, neural, and skeletal) of NC-derived cell-types, as well as cell-types derived from the known non-NC sites of sox10 expression, including otic epithelium and oligodendrocytes. This line provides an invaluable tool for the further study of zebrafish NC development and NC-derived stem cells as well as that of the otic vesicle and oligodendrocytes. genesis 50:750–757, 2012. © 2012 Wiley Periodicals, Inc.

The gene cloning, purification, properties, kinetics, and antifungal activity of chitinase from marine Streptomyces sp. DA11 associated with South China sponge Craniella australiensis were investigated. Alignment analysis of the amino acid sequence deduced from the cloned conserved 451 bp DNA sequence shows the chitinase belongs to ChiC type with 80% similarity to chitinase C precursor from Streptomyces peucetius. Through purification by 80% ammonium sulfate, affinity binding to chitin and diethylaminoethyl-cellulose anion-exchange chromatography, 6.15-fold total purification with a specific activity of 2.95 Umg(-1) was achieved. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed a molecular weight of approximately 34 kDa and antifungal activities were observed against Aspergillus niger and Candida albicans. The optimal pH, temperature, and salinity for chitinase activity were 8.0, 50 degrees C, and 45 g per thousand psu, respectively, which may contribute to special application of this marine microbe-derived chitinase compared with terrestrial chitinases. The chitinase activity was increased by Mn(2+), Cu(2+), and Mg(2+), while strongly inhibited by Fe(2+) and Ba(2+). Meanwhile, SDS, ethyleneglycoltetraacetic acid, urea, and ethylenediaminetetraacetic acid were found to have significantly inhibitory effect on chitinase activity. With colloidal chitin as substrates instead of powder chitin, higher V (max) (0.82 mg product/min.mg protein) and lower K (m) (0.019 mg/ml) values were achieved. The sponge's microbial symbiont with chitinase activity may contribute to chitin degradation and antifungal defense. To our knowledge, it was the first time to study sponge-associated microbial chitinase.