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This paper reports a portable fluorescent sensor platform containing multiple excitation light illumination for quantification and differentiation of multiple analytes. The fluorescent sensor platform utilizes: (i) three different wavelengths of light emitting diodes (LEDs) for selectively stimulating target analytes; (ii) a sensitive photodetector for corresponding fluorescence measurements; (iii) a custom-built electronic system for data measurement and storage; and (iv) a compact three-dimensional printed housing for the developed sensor platform. Based on the fluorescent emission pattern obtained from each target analyte, multivariate analytical methods were applied to differentiate one analyte from the other in a mixture of multiple analytes. The fluorescent sensor platform was tested to selectively detect two target phytoplankton species: Chlorella vulgaris and Spirulina. Fluorescent emission of phytoplankton is caused by stimulation of photosynthetic pigments and is widely utilized to quantify and classify phytoplankton groups. Biomass estimation was therefore conducted by measuring chlorophyll a fluorescence emission for green algae (Chlorella vulgaris) using blue LED excitation and phycocyanin fluorescence emission for cyanobacteria (Spirulina) using amber LED excitation. The results demonstrated the viability of the developed device as a portable generic fluorescence sensor platform for simultaneously detecting various biochemical analytes.

Light effect on cultures of microalgae has been studied mainly on single species cultures. Cyanobacteria have photosynthetic pigments that can capture photons of wavelengths not available to chlorophylls. A native Louisiana microalgae (Chlorella vulgaris) and cyanobacteria (Leptolyngbya sp.) co‐culture was used to study the effects of light quality (blue–467 nm, green–522 nm, red–640 nm and white–narrow peak at 450 nm and a broad range with a peak at 550 nm) at two irradiance levels (80 and 400 μmol m(−2) s(−1)) on the growth, species composition, biomass productivity, lipid content and chlorophyll‐a production. The co‐culture shifted from a microalgae dominant culture to a cyanobacteria culture at 80 μmol m(−2) s(−1). The highest growth for the cyanobacteria was observed at 80 μmol μmol m(−2) s(−1) and for the microalgae at 400 μmol m(−2) s(−1). Red light at 400 μmol m(−2) s(−1) had the highest growth rate (0.41 d(−1)), biomass (913 mg L(−1)) and biomass productivity (95 mg L(−1) d(−1)). Lipid content was similar between all light colors. Green light had the highest chlorophyll‐a content (1649 μg/L). These results can be used to control the species composition of mixed cultures while maintaining their productivity.

This work reports the development of a field-deployable and fully handheld fluorometer for environmental water monitoring. Our developed fluorimeter can detect both green algae and cyanobacteria (blue-green algae) while simultaneously differentiating and measuring two different species by selectively measuring chlorophyll a fluorescence from green algae and phycocyanin fluorescence from blue-green algae. As a demonstration, chlorophyll a and phycocyanin photopigments were estimated and differentiated. The system was also tested with an environmental water sample collected from a lake to validate the system functionality. The presented results suggest that our developed fluorimeter could be used as a portable water quality monitoring system for detection of different photopigment of algae.

Current culture methods based on monocultures under phototrophic regimes are prone to contamination, predation, and collapse. Native cultures of multiple species are adapted to the local conditions and are more robust against contamination and predation. Growth, lipid and biomass productivity of a Louisiana native coculture of microalgae (Chlorella vulgaris) and cyanobacteria (Leptolyngbya sp.) in heterotrophic and mixotrophic regimes were investigated. Dextrose and sodium acetate at C:N ratios of 15:1 and 30:1 under heterotrophic (dark) and mixotrophic (400 μmol m−2 s−1) regimes were compared with autotrophic controls. The carbon source and C:N ratio impacted growth and biomass productivity. Mixotrophic cultures with sodium acetate (C:N 15:1) resulted in the highest mean biomass productivity (156 g m−3 d−1) and neutral lipid productivity (24.07 g m−3 d−1). The maximum net specific growth rate (U) was higher (0.97 d−1) in mixotrophic cultures with dextrose (C:N 15:1) but could not be sustained resulting in lower total biomass than in mixotrophic cultures with acetate (C:N 15:1), with a U of 0.67 d−1. The ability of the Louisiana coculture to use organic carbon for biomass and lipid production makes it a viable feedstock for biofuels and bioproducts.

Recent interest in the use of microalgae for the production of biofuels and bioproducts has stimulated an interest in methods to enhance the growth rate of microalgae. This review examines past work involving the stimulation of Chlorella sp. growth and metabolite production by plant growth substances as well as by mixed cultures of Chlorella sp. with bacteria. Plant growth substances known to regulate Chlorella sp. growth and metabolite production include auxins, cytokinins, abscisic acid, polyamines, brassinosteroids, jasmonic acid, salicylic acid, and combinations of two or three of the aforementioned substances. Mixed cultures of bacteria are examined, including both natural bacteria–algae consortia and artificially induced symbioses. For natural consortia, commonly occurring bacterial species, including the genera Brevundimonas and Sphingomonas, are discussed. For artificially induced symbioses, the use of the nitrogen-fixing bacterium Azospirillum is examined in detail. In particular, a variety of studies have involved the coimmobilization of Chlorella sp. with Azospirillum sp. in alginate beads, with the goal of using the mixed culture to treat wastewater. In summary, the use of plant growth substances and mixed cultures provides two methods to increase the growth of Chlorella sp., whether for the production of lipids for biofuels, the production of bioproducts, the treatment of wastewater, or a variety of other reasons.

A locally isolated co-culture of two photosynthetic species [Chlorella vulgaris (Chlorophyta) and Leptolyngbya sp. (Cyanobacteria)] displayed enhanced growth when compared to a Chlorella monoculture; however, the biological mechanisms driving such improvement are currently not well understood. To investigate these mechanisms, this study examined the differential gene expression in the Chlorella between the co-culture and the monoculture. Suppression subtractive hybridization was performed between mRNA from Chlorella in the co-culture and in a monoculture, and 105 genes were identified as being putatively differentially expressed. Nine of these genes, corresponding to the key functional categories of energy, metabolism, and protein synthesis, were further examined using quantitative real-time PCR and showed differential regulation of photosystem I and photosystem II and upregulation of stress-response genes and a gene encoding an oil-globule-associated gene in the co-culture Chlorella. This differential gene expression study of a Chlorella/cyanobacteria co-culture will aid in the development of culture strategies capable of taking advantage of these differences for the production of biomass and bioproducts of interest. Knowledge of the underlying genetic causes of the changes in growth and productivity of the species in co-culture provides insights on possible target genes for optimization of the culture.

Aims: To design a primer set enabling the identification through PCR of high-quality DNA for routine and high-throughput genomic screening of a diverse range of cyanobacteria. Methods and Results: A codon-equivalent multiple alignment of the phycocyanin alpha-subunit coding sequence (cpcA) of 22 cyanobacteria was generated and analysed to produce a single degeneracy primer set with virtually uniform product size. Also, an 18S ribosomal RNA detection set is proposed for rejecting false positives. The primer sets were tested against five diverse cyanobacteria, Chlorella vulgaris, Saccharomyces cerevisiae, and Escherichia coli. All five cyanobacteria showed positive amplification of cpcA product with homogeneous fragment length, and no products were observed for any other organism. Additionally, the only product formation observed for the 18S rRNA set was in C. vulgaris and S. cerevisiae. Conclusions: The newly proposed primer set served as effective check primers for cyanobacteria. Cyanobacteria gDNA had a positive, homogenous result, while other bacteria, eukaryotes and alga tested were negative. Significance and Impact of the Study: These novel, broad-spectrum primers will greatly increase the utility of PCR on newly discovered cyanobacterial species.

Microalgal biomass produced in indoor photobioreactors can be used as inoculum for large-scale outdoor cultures or directly for the production of high-value bioproducts due to the higher control of these cultures compared with outdoor systems. One of the main costs of indoor microalgal cultures is the illumination. This work can be used as a basis for the optimization of the light source for indoor microalgal biomass production, based on the light source type, irradiance, productivity, growth rate, attenuation coefficients, and contaminant growth on the reactor's side-walls. Four commercially available near 400-W artificial light sources for microalgal cultures (metal halide (MH), high-pressure sodium (HPS), Son Agro®, and fluorescent) were compared. The light elevation and the surface scalar irradiance were shown to have a linear relationship. The attenuation coefficient in air (ka) was highest with Son Agro®. A linear partition of the attenuation coefficient between the water and biomass and an exponential relationship between average scalar irradiance and depth were found. An empirical overall scalar attenuation coefficient for each light source was obtained. The lowest maximum observed growth rate was obtained with fluorescent light (0.98 d−1) and the highest with Son Agro® (2.39 d−1). The highest growth on the reactor's wall was obtained with Son Agro®. Further studies resulted in a higher maximum specific growth rate and optimum irradiance for HPS (2.37 d−1 and 460 μmol s−1 m−2) compared with those observed with MH (1.73 d−1 and 391 μmol s−1 m−2).

The biological rhythms of microalgal growth within a hydraulically integrated serial turbidostat algal reactor (HISTAR) were examined after comparison of a simple mechanistic productivity model with actual data yielded a standard error of prediction (SEP) of 62%. The data used for this study were taken on cultures of Selenastrum capricornutum grown under continuous 400-watt metal halide lighting. Fourier series analysis (up to five harmonics) was used to model the biorhythms and differentiate them from stochastic processes. Regression analyses revealed that the best Fourier series fit for the data was a three harmonic summation. Regression analyses on additional harmonic summations did not increase r2 by more than 1%. The three harmonics were summed and incorporated into the growth term of the simple model, and the resultant full model was calibrated. The mechanistic HISTAR productivity model was greatly enhanced by the addition of the biological rhythm component, resulting in a SEP of

Bioassay guided isolation of an antitubercular extract of the aerial parts of Thalia multiflora led to the isolation of nine stigmast-5-ene and stigmasta-5,22-dien steroids, four isorhamnetin and quercetin flavonoid glycosides, two ceramides, an indole alkaloid and two simple phenolic compounds. Stigmast-5-en-3beta-ol-7-one (2), stigmast-4-ene-6beta-ol-3-one (3), stigmast-5,22-dien-3beta-ol-7-one (7) and stigmast-4,22-dien-6beta-ol-3-one (8) were found to be the most active compounds with MIC values of 1.98 +/- 0.02, 4.2 +/- 0.17, 1.0 +/- 0.06 and 2.2 +/- 0.3 microg/mL, respectively. Compounds 2, 3, 7 and 8 were not cytotoxic to Vero cells at 102 microg/mL. This investigation constitutes the first report of a chemical study of a species of the genus Thalia.

Chemical investigation of the aerial parts of Anadenanthera colubrina led to the isolation of a new flavonoid named anadanthoflavone ( 1), along with 11 known compounds: alnusenol, lupenone, lupeol, betulinic acid, alpha-amyrin, beta-amyrin, beta-sitosterol, stigmasterol, apigenin, 4-hydroxybenzoic acid and cinnamic acid. The isolated compounds were evaluated for their inhibitory activity on human platelet 12-lipoxygenase (12-hLO), human reticulocyte 15-lipoxygenase (15-hLO) and soybean lipoxygenase-1 (15-sLO). Compound 1 was found to be active against 12-hLO and 15-hLO with IC50 values of 13 +/- 3 microM and 17 +/- 3 microM, respectively. Apigenin selectively inhibited the activity of 15-hLO (IC50 : 4.0 +/- 1 microM), while lupenone, lupeol and alpha-amyrin were found active against 15-sLO (IC50 : 22 +/- 3 microM, 35 +/- 9 microM and 15 +/- 3 microM, respectively).

Mycothiol ligase (MshC) is a key enzyme in the biosynthesis of mycothiol, a small molecular weight thiol that is unique to actinomycetes and whose primary role is to maintain intracellular redox balance and remove toxins. MshC catalyzes the adenosine triphosphate (ATP)-dependent condensation of cysteine and glucosamine-inositol (GI) to produce cysteine-glucosamine-inositol (CGI). MshC is essential to Mycobacterium tuberculosis and therefore represents an attractive target for chemotherapeutic intervention. A screening protocol was developed to identify MshC inhibitors based on quantification of residual ATP using a coupled luminescent assay. The protocol was used to screen a library of 3100 compounds in a 384-well plate format (Z'>or=0.65). Fifteen hits (0.48%) were identified from the screen, and 2 hits were confirmed in a secondary assay that measures production of CGI. The structures of both hits contain N-substituted quinolinium moieties, and the more potent of the 2-namely, dequalinium chloride-inhibits MshC with an IC50 value of 24+/-1 microM. Further studies showed dequalinium to be an ATP-competitive inhibitor of MshC, to bind MshC with a KD of 0.22 microM, and to inhibit the growth of M. tuberculosis under aerobic and anaerobic conditions with minimum inhibitory and anaerobic bactericidal concentrations of 1.2 and 0.3 microg/mL, respectively. The screening protocol described is robust and has enabled the identification of new MshC inhibitors.

A continuous microwave heating system was tested for its effectiveness at removing potentially invasive organisms during deballasting operations. Four different organisms, namely Nannochloropsis oculata (microalgae), Artemia nauplii, Artemia adults and Crassosstrea virginica (oyster larvae) normally found in ballast water were investigated in a controlled study to quantify their survival after continuous microwave heating of synthetic ballast water. The experiments were performed in the microwave system using a 2 x 2 factorial design with power (2.5 and 4.5 kW) and flow rate (1.0 and 2.0 lpm) and the organisms subsequently subjected to different holding times. The control treatment was performed in a water bath using the same temperatures and holding times as in the case of the microwave treatment. Overall, the results obtained indicated that the microwave system was more effective in eliminating the organisms when compared with the control treatment. In most cases there were no survivors present after the microwave treatment at holding times above 100 s, and temperatures as low as 50 degrees C particularly for oyster larvae and Artemia adults. The results are promising, indicating that this technology has the potential to be an effective tool in controlling/preventing the introduction of invasive species into native environments.

Mycothiol ligase (MshC) is a key enzyme in the biosynthesis of mycothiol, a small molecular weight thiol found in Mycobacteria spp. and other actinomycetes. Mycothiol plays a fundamental role in these organisms by helping to provide protection from the effects of reactive oxygen species and electrophiles, including many antibiotics. It has recently been demonstrated that the MshC gene and more generally the production of mycothiol are essential to Mycobacterium tuberculosis, indicating that MshC may represent a novel target for new classes of antituberculars. Because MshC cannot be expressed heterologously in Escherichia coli and isolation from Mycobacterium smegmatis is impractical, we have optimized the E. coli-M. smegmatis shuttle vector pACE for cloning and recombinant expression of MshC (under control of an acetamidase-inducible promoter). To improve expression levels and simplify purification, we further constructed three N-terminal-MshC fusion proteins where N-terminal tags included the B1 domain of streptococcal protein G (to give GB1-MshC), glutathione-S-transferase (to give GST-MshC) and maltose binding protein (to give MBP-MshC), for expression in M. smegmatis. By expressing all three fusion proteins in a mutant strain of M. smegmatis mc(2)155, namely I64 L205P MshC M. smegmatis which lacks mycothiol ligase activity, we demonstrate in vivo mycothiol ligase activity for each construct. Recombinant GST-MshC and MBP-MshC were isolated in one step by affinity chromatography in a yield of 0.7 and 1.2 mg fusion protein/L and exhibited specific activities of 9 nmolmin(-1)mg(-1) and 25 nmolmin(-1)mg(-1), respectively.

Bioassay guided isolation of an antibacterial extract prepared from the fermentation broth of a Micromonospora sp. P1068 led to the isolation of eight compounds identified as (3R) 3,4',7-trihydroxy-isoflavanone (1), 3-hydroxydehydrodaidzein, daidzein (2), 3-methyl-1H-indole-2-carboxylic acid (3), 1H-indole-3-carboxaldehyde (4), 3-(p-hydroxyphenyl)-N-methylpropionamide, N-methylphloretamide (5), phenyl acetic acid (6), 2-hydroxy phenyl acetic acid (7) and 4-hydroxy-5-methoxy-benzoic acid (8). Compounds 1 and 5 were found to be novel chemical entities while 3 was isolated from a natural source for the first time. All compounds were evaluated for their antimicrobial activities against a panel of clinically significant microorganisms. Compound 4 was active against Staphylococcus aureus (MIC, 32 microg/ml), Enterococcus faecium (MIC, 32 microg/ml) and Escherichia coli (MIC, 64 microg/ml).

Four novel compounds consisting of two new pimaranes, lecheronol A (1) and lecheronol B (2), an acylated cycloartane, 3-O-beta-lauroyl-cycloart-(23E)-en-25-ol (10), and a highly oxygenated novel chalconoid, alpha,beta,3,4,5,2',4',6'-octahydroxydihydrochalcone (12), were isolated along with seven known triterpene derivatives and three flavonol glucosides from Mycobacterium tuberculosis growth-inhibiting fractions of the CH(2)Cl(2)/MeOH (1:1) extract of the aerial parts of Sapium haematospermum. Compounds 1, 3 (3 alpha-hydroxyolean-12-ene), 8 [3 alpha-hydroxylup-20(29)-en], and 9 (cycloartanol) were found most active, with MIC values of 4, 12.2, 13.4, and 8 microg/mL, respectively. Cytotoxicity tests in Vero cells for compounds 1, 3, 8, and 9 gave IC(50) values of 104.8, 127.2, 127.2, and 102.4 microg/mL, respectively.

Three new cycloartane-type triterpenes, 16 alpha-hydroxymollic (1), 15 alpha-hydroxymollic (2), and 7 beta,16 beta-dihydroxy-1,23-dideoxyjessic acids (3), were isolated from the aerial parts of Acalypha communis. The structures of the novel triterpenes were determined by spectroscopic methods as well as chemical derivatization. These compounds were tested for their antimicrobial activity against Gram-positive and -negative bacteria. Compounds 1-3 exhibited moderate antimicrobial activity (MIC 8, 32, 8 microg/mL, respectively) against vancomycin-resistant enterococci. In addition, compound 1 was found to be active against methicillin-resistant staphylococci. In contrast, compounds 1-3 were poorly active against Gram-negative bacteria. Compound 3 was tested in an in vivo model; it did not provide protection to mice infected with Staphylococcus aureus.