Morphological and molecular characterization of cyanobacteria from a Brazilian facultative wastewater stabilization pond and evaluation of microcystin production

The cyanobacterial population in the Cajati waste stabilization pond system (WSP) from São Paulo State, Brazil was assessed by cell isolation and direct microscope counting techniques. Ten strains, belonging to five genera (Synechococcus, Merismopedia, Leptolyngbya, Limnothrix, and Nostoc), were isolated and identified by morphological and molecular analyses. Morphological identification of the isolated strains was congruent with their phylogenetic analyses based on 16S rDNA gene sequences. Six cyanobacterial genera (Synechocystis, Aphanocapsa, Merismopedia, Lyngbya, Phormidium, and Pseudanabaena) were identified by direct microscope inspection. Both techniques were complementary, since, of the six genera identified by direct microscopic inspection, only Merismopedia was isolated, and the four other isolated genera were not detected by direct inspection. Direct microscope counting of preserved cells showed that cyanobacteria were the dominant members (>90%) of the phytoplankton community during both periods evaluated (summer and autumn). ELISA tests specific for hepatotoxic microcystins gave positive results for six strains (Synechococcus CENA108, Merismopedia CENA106, Leptolyngbya CENA103, Leptolyngbya CENA112, Limnothrix CENA109, and Limnothrix CENA110), and for wastewater samples collected from raw influent (3.70 μg microcystins/l) and treated effluent (3.74 μg microcystins/l) in summer. Our findings indicate that toxic cyanobacteria in WSP systems are of concern, since the treated effluent containing cyanotoxins will be discharged into rivers, irrigation channels, estuaries, or reservoirs, and can affect human and animal health.     

Genetic analyses of anthocyanin concentrations and intensity of red bulb color among segregating haploid progenies of onion

Higher concentrations of anthocyanins in vegetables are important for attractive appearance and may offer health benefits for consumers. The red color of onion (Allium cepa) bulbs is due primarily to the accumulation of anthocyanins. The goal of this study was to identify chromosome regions that significantly affect concentrations of anthocyanins and soluble solids in onion bulbs. Segregating haploid plants from the cross of yellow (OH1) and red (5225) inbreds were asexually propagated and bulbs were produced in replicated trials across three environments. Concentrations of soluble solids were measured at 30 days after harvest and quantitative analyses revealed a significant region on chromosome 5. Analyses using a binary model for segregation of red versus yellow bulbs revealed a significant region on chromosome 7 and two regions linked in repulsion phase on chromosome 4. These results are consistent with the complementary two-locus model previously proposed to control red versus yellow bulb colors in onion. The region on chromosome 7 mapped to the same location as the R locus, and the regions on chromosome 4 may correspond to the L and L2 loci. The intensity of red bulb color was assessed visually by a panel of evaluators and by amounts of anthocyanins [peonidin 3-glucoside and cyanidin 3-(6″-malonoyl-laminaribioside)] measured by high-performance liquid chromatography. Quantitative analyses using a normal model revealed significant quantitative trait loci on chromosomes 1, 4 and 8 affecting anthocyanin concentrations, and yellow onion contributed beneficial genetic variation to enhance red bulb color. Significant correlations were observed between these anthocyanin concentrations and panel scores, indicating that visual selection should be effective for increasing anthocyanin levels in onion bulbs. These selected populations may be more attractive to consumers, potentially provide health benefits from increased anthocyanin consumption, and be a source of natural colorants.     

Lime enhanced chromium removal in advanced integrated wastewater pond system

The removal of trivalent chromium from a combined tannery effluent in horizontal settling tanks and subsequent Advanced Integrated Wastewater Pond System (AIWPS) reactors was investigated. The raw combined effluent from Modjo tannery had pH in the range of 11.2-12. At this pH, a trivalent chromium removal of 46-72% was obtained in the horizontal settling tanks after a one-day detention time. Trivalent chromium precipitated as chromium hydroxide, Cr(OH)3. 58-95% Cr(III) was removed in the advanced facultative pond (AFP) where the water column pH of 7.2-8.4 was close to pH 8, which is the optimum precipitation pH for trivalent chromium. Chromium removals in the secondary facultative pond (SFP) and maturation pond (MP) were 30-50% and 6-16%, respectively. With Cr(III) concentration of 0.2-0.8 mg/l in the final treated effluent, the AIWPS preceded by horizontal settling tanks produced effluent that could easily meet most of the current Cr(III) discharge limits to receive water bodies.     

Inheritance of the red color in tilapias

The inheritance of the red color was studied in two different varieties of tilapia which are both considered as hybrids of Oreochromis mossambicus. Crosses between red tilapia from the Philippines (PRT) and Sarotherodon galilaeus, or Oreochromis aureus gave a 1:1 ratio of red: normal and crosses between F₁ black fish gave only black offspring. On the other hand crosses between the F₁ red fish gave a 3:1 ratio of red:black and crosses between F₁ red and black offspring gave a 1:1 ratio. These results lead to the conclusion that red color is dominant over the normal black color and controlled by a single autosomal gene (R). A unique phenotype named albino with black eyes was observed among offspring of PRT and a presumed model of inheritance of this trait is proposed. Genetic analysis of a second variety of red tilapia (derived from an unknown origin) showed the following results: crosses between parents and between their F₁ offspring consistently gave 100% red fish and crosses between this red tilapia and Oreochromis aureus gave 100% black offspring. The crosses between red and black F₁ of these last two crosses gave a 1:1 ratio and crosses carried out between the black F₁ offspring gave a 1:3 ratio of red:black. It may be concluded from these results that the black color is dominant in this strain and that this color is controlled by a single autosomal gene (B). The presumed mode of action of the dominant gene (R) as well as of the recessive gene (b) are discussed.     

The role of sulphidogenesis in anaerobic treatment phase of tannery wastewater treatment in advanced integrated wastewater pond system

An outdoor experiment was conducted to study the competitionbetween Sulphate Reducing Bacteria (SRB) and Methanogenic Archaea (MA) in anaerobictreatment phase of tannery wastewater treatment in pilot-scale Advanced FacultativePond (AFP). The relative electron flow towards sulphate reduction was higher (59–83%) than towardsmethanogenesis (17–41%), although the COD recovery within thereactor varied between 15 and 90%. The results also demonstrated that the flow of electrons towards SRBincreased with increase of the sulphate concentration and decrease of the COD : SO₄ ⁼ ratio.     

Isolation,identification and growth conditions of photosynthetic bacteria found in seafood processing wastewater

Four photosynthetic bacteria, isolated from 14 samples taken from seafood processing plants, were identified as species of Rhodocyclus gelatinosus, belonging to the purple, non-sulphur bacteria of the family Rhodospirillaceae. Cultivation in synthetic medium under four different conditions indicated that all four strains gave maximum carotenoid and bacteriochlorophyll synthesis under anaerobic conditions in the light, with values of 11 to 12.6 and 102 to 108 mg/g dry cell wt, respectively. These values are 87% higher than the pigment content obtained from aerobic cultivation, although the cell biomass of all strains (1.7 to 2.3 g/l) was 22 to 38% higher under aerobic conditions. Protein content was always between 32 and 43%. The specific growth rates of all isolates in aerobic cultivation (0.04 to 0.06 h^-1) were twice those in anaerobic conditions in the light. No growth occurred in anaerobic conditions in the dark.     

造纸废液氧化塘纤维素酶产生菌群的分析与产酶菌株的筛选

【目的】解析造纸废液氧化塘中产纤维素酶微生物的群体组成和结构;筛选并获得一批纤维素酶产生菌,丰富菌株资源,并为纤维素酶的工业应用和环境污染的生物处理奠定基础。【方法】基于16S rRNA基因序列信息,系统考察了造纸废液氧化塘环境中产纤维素酶细菌的群体组成和结构,并通过测定纤维素酶在不同pH条件下酶活变化考察所产纤维素酶的特性。【结果】造纸废液氧化塘中产纤维素酶微生物具有丰富的多样性。在分类上分属于Firmicutes、Actinobacteria、Alpha-proteobacteria和Gamma-proteobacteria 4个门(亚门)15种。来自泥液混合样和黑液排污口泥样的产纤维素酶细菌群体多样性最为丰富,由6-7个种的细菌组成;而来自强碱性的黑液下层样品中微生物的多样性则较为贫乏,主要由来自Bacillus类细菌组成。分离菌株除酸性纤维素酶产生菌外,碱性纤维素酶和中性纤维素酶产生菌也较为丰富,且其分布与样品来源有紧密的关系。【结论】对造纸废液氧化塘产纤维素酶微生物群体组成和结构的研究,不仅有利于对新菌株资源的挖掘,也可为特殊环境的微生物学研究提供参考。     

Pseudomonas aeruginosa,a facultative pathogen of red palm weevil,Rhynchophorus ferrugineus

Pseudomonas aeruginosa was identified as a facultative pathogen of red palm weevil. Intra-haemocoelic injection of the pathogen within larvae and pre-pupae was more effective at killing the insects [with a median lethal dose (LD₅₀) of 9×10² to 2×10³ bacteria/insect] than inoculation by force feeding (LD₅₀ of 10⁵ to 4×10⁵ bacteria/insect) or by wading the insects in a suspension of the pathogen (LD₅₀ of 10⁵ to 2×10⁵ bacteria/insect). Injection of 3×10³ bacteria/insect killed 69% of larvae; small larvae were more susceptible (LD₅₀ of 9×10⁵ bacteria/larva) than either larger larvae (LD₅₀ of 10³ bacteria/larva) or pre-pupa. The median time to death of the small larvae following injection of P. aeruginosa was about 6 days but that following force feeding or wading was about 8 days. A secondary invader, Serratia marcescens, had no effect on the pathogenicity of P. aeruginosa but hastened death of larvae by about 3 days.A. Banerjee and T.K. Dangar were with the Central Plantation Crops Research Institute, Regional Station, Kayangulam 690 533, Kerala, India. They are now with the Central Rice Research Institute. Cuttack 753 006, Orissa, IndiaCPCRI research paper no. 870.     

Optimization of a raceway pond system for wastewater treatment: a review

Microalgae are photosynthetic microorganisms with potential for biofuel production, CO₂ mitigation and wastewater treatment; indeed they have the capacity to assimilate pollutants in wastewaters. Light supply and distribution among the microalgae culture is one of the major challenges of photo-bioreactor design, with many studies focusing on microalgae culture systems such as raceway ponds (RWP), widely used and cost-effective systems for algal biomass production. This review focuses on possible improvements of the RWP design in order to achieve optimal microalgal growth conditions and high biomass productivities, to minimize energy consumption and to lower the capital costs of the pond. The improvement strategy is based on three aspects: (1) hydrodynamic characteristics of the raceway pond, (2) evaluation of hydrodynamic and mass transfer capacities of the pond and (3) design of the RWP. Finally, a possible optimal design for the RWP is discussed in the context of wastewater treatment.     

Seeing red: color vision in the largemouth bass

How animals visually perceive the environment is key to understanding important ecological behaviors, such as predation, foraging, and mating. This study focuses on the visual system properties and visual perception of color in the largemouth bass Micropterus salmoides. This study (1) documents the number and spectral sensitivity of photoreceptors,(2) uses these parameters to model visual perception, and (3) tests the model of color perception using a behavioral assay. Bass possess single cone cells maximally sensitive at 535 nm, twin cone cells maximally sensitive at 614 nm, and rod cells maximally sensitive at 528 nm. A simple model of visual perception predicted that bass should not be able to discern between chartreuse yellow and white nor between green and blue. In contrast, bass should be able to discern red from all achromatic (i.e., gray scale) stimuli. These predictions were partially upheld in behavioral trials. In behavioral trials, bass were first trained to recognize a target color to receive a food reward, and then tested on their ability to differentiate between their target color and a color similar in brightness. Bass trained to red and green could easily discern their training color from all other colors for target colors that were similar in brightness (white and black, respectively). This study shows that bass possess dichromatic vision and do use chromatic (i.e., color) cues in making visual-based decisions.     

Elevated spring testosterone increases parasite intensity in male red grouse

The expression of testosterone-dependent sexual traits mightsignal the ability of their bearers to cope with parasite infections.According to the immunocompetence handicap hypothesis (IHH),such signals would be honest because physiological costs oftestosterone, such as a reduced ability to control parasiteinfections, would prevent cheating. We tested whether testosteronewould affect the outcome of a standardized parasite challengein red grouse, using a main parasite of the species, the nematodeTrichostrongylus tenuis. We caught males in spring, removedtheir nematode parasites, and implanted them with testosteroneor empty implants, as controls. After 1 month, they were reinfectedwith a standard dose of infective T. tenuis parasites. Whenchallenged, testosterone males had relatively less globulinrelative to albumin plasma proteins than control males, an indicationthat they had experienced increased physiological stress. Testosterone-treatedmales had significantly more T. tenuis parasites than controlsin the next autumn and also had more coccidia and lost moreweight than controls. Testosterone-treated males neverthelessbenefited from their elevated spring testosterone: they hadbigger sexual ornaments than controls both in spring and autumn,and they tended to have a higher pairing and breeding successthan controls. Our results supported the IHH in showing thatelevated testosterone impaired the ability of males to copewith a standardized challenge by a dominant parasite. Testosteronethus plays a key role in mediating trade-offs between reproductiveactivities and parasite defense, and testosterone-dependentcomb size might honestly signal the ability of red grouse tocontrol T. tenuis infection.     

Nitrogen and phosphorus interchange between sediments and overlying water of a wastewater retention pond

Nitrogen and P interchange between the sediments and the overlying water of a simulated retention pond used for wastewater treatment were evaluated under conditions of seasonal temperature fluctuations and varying physico-chemical conditions (exposing floodwater surface to daylight vs. dark and turbulent vs. quiscent floodwater). Natural sediment columns obtained from two types of field retention ponds were used. One type of retention pond consisted of calcareous clay loam sediment while the sediment of second retention pond contained organic soil. Nutrient interchange between sediments and the overlying water was measured once a month over a period of one year. Nitrogen removal rates from floodwater were controlled by the initial floodwater NH ₄ ⁺ and NO ₃ ^? concentration, rate of NH ₄ ⁺ diffusion from the sediments to the overlying water, ammonification in the sediments, NH₃ volatilization and nitrification at the sediment-water interface, and denitrification in the sediments. Under the conditions studied, NH ₄ ⁺ concentrations of the floodwater were in the range of 0.01 to 0.05 µg/ml, while NO ₃ ^? concentrations were in the range of 0.27 to 0.78 µg/ml. Sediments with organic soil were found to be less effective in the removal of floodwater organic N, organic C and P, compared to the sediments with calcareous clay loam. Phosphorus exchange rates were dependent on the capacity of the sediment to adsorb or desorb P. Total P exchange rates were in the range of ?1.04 to 0.34 mg P/m² day. Seasonal temperature fluctuations, turbulent vs. quiscent water conditions or exposing the floodwater surface to daylight or dark had very little effect on N and P exchange rates.     

Microbial quality of common carp and pikeperch fingerlings cultured in a pond fed with treated wastewater

A pond with a surface area of 0.94 ha and a maximum depth of 1.6 m, situated on land owned by a wastewater treatment plant in Olsztynek (Poland), was filled with water from underground springs in the pond bottom. Twice during the production season, the pond was fed with sewage which had been biologically treated in sequencing batch reactors (SBR). No commercial feed or medicinal products were applied to the pond and natural feed in the pond was the only source of nutrition for the fish. After the production season, pikeperch and carp fingerlings (aged 0+), weighed 8.4 ± 1.2 g fish^?1 and 62.1 ± 13.6 g fish^?1, respectively.The microbiological examinations included tests of the pond water and the contents of the digestive tract, skin mucus and the muscles of the fingerlings. In the water the total cell count, heterotrophic bacteria count at a temperature of 22 °C and 37 °C (HPC 22 °C and 37 °C), coliforms, fecal coliforms, Streptococcus faecalis, Salmonella sp. and Aeromonas hydrophila, were recorded. The same groups of bacteria were noted in the analyzed fish tissue without the total cell count. In addition, the antibiotic sensitivity of A. hydrophila, isolated from all the examined environments, was tested.The low count of all examined groups of bacteria in the pond water was noted. The common carp tissues were more contaminated than the pikeperch tissues, but the microbial quality of both species was satisfactory. A. hydrophila strains proved to be highly sensitive to the tested antibiotics. The results of this study indicate that a high microbiological quality in the fingerlings was achieved thanks to the seasonal feeding of pond water by treated sewage.     

Seeing red: behavioral evidence of trichromatic color vision in strepsirrhine primates

Among primates, catarrhines (Old World monkeys and apes) andcertain platyrrhines (New World monkeys) possess trichromaticcolor vision, which might confer important evolutionary advantages,particularly during foraging. Recently, a polymorphism has beenshown to shift the spectral sensitivity of the X-linked opsinprotein in certain strepsirrhines (e.g., Malagasy lemurs); however,its behavioral significance remains unknown. We assign genotypesat the X-linked variant to 45 lemurs, representing 4 species,and test if the genetic capacity for trichromacy impacts foragingperformance, particularly under green camouflage conditionsin which red detection can be advantageous. We confirm polymorphismat the critical site in sifakas and ruffed lemurs and fail tofind this polymorphism in collared lemurs and ring-tailed lemurs.We show that this polymorphism may be linked to "behavioraltrichromacy" in heterozygous ruffed lemurs but find no comparableevidence in a single heterozygous sifaka. Despite their putativedichromatic vision, female collared lemurs were surprisinglyefficient at retrieving both red and green food items undercamouflage conditions. Thus, species-specific feeding ecologiesmay be as important as trichromacy in influencing foraging behavior.Although the lemur opsin polymorphism produced measurable behavioraleffects in at least one species, the ruffed lemur, these effectswere modest, consistent with the modest shift in spectral sensitivity.Additionally, the magnitude of these effects varied across individualsof the same genotype, emphasizing the need for combined geneticand behavioral studies of trichromatic vision. We conclude thattrichromacy may be only one of several routes toward increasedforaging efficiency in visually complex environments.     

Photooptic response of blood plasma to low intensity red light

Photooptical response, both of the whole blood and of its non-pigmented fraction-plasma to the low-intensity red light is investigated. For the case of the blood irradiation in vitro it is shown that the mechanism of the low-intensity red light effect on the blood is not directly associated with the pigmented molecular complexes concentrated in erythrocytes. Thus the effect of the low-intensity red light on living organisms includes the mechanisms not using light absorption by the specialized macromolecule--photoreceptor as a primary photophysical action.