Mixotrophy in a Local Strain of Nannochloropsis granulata for Renewable High-Value Biomass Production on the West Coast of Sweden

A local strain of Nannochloropsis granulata (Ng) has been reported as the most productive microalgal strain in terms of both biomass yield and lipid content when cultivated in photobioreactors that simulate the light and temperature conditions during the summer on the west coast of Sweden. To further increase the biomass and the biotechnological potential of this strain in these conditions, mixotrophic growth (i.e., the simultaneous use of photosynthesis and respiration) with glycerol as an external carbon source was investigated in this study and compared with phototrophic growth that made use of air enriched with 1–2% CO₂. The addition of either glycerol or CO₂-enriched air stimulated the growth of Ng and theproduction of high-value long-chain polyunsaturated fatty acids (EPA) as well as the carotenoid canthaxanthin. Bioassays in human prostate cell lines indicated the highest antitumoral activity for Ng extracts and fractions from mixotrophic conditions. Metabolomics detected betaine lipids specifically in the bioactive fractions, suggesting their involvement in the observed antitumoral effect. Genes related to autophagy were found to be upregulated by the most bioactive fraction, suggesting a possible therapeutic target against prostate cancer progression. Taken together, our results suggest that the local Ng strain can be cultivated mixotrophically in summer conditions on the west coast of Sweden for the production of high-value biomass containing antiproliferative compounds, carotenoids, and EPA.     

Evaluation of the Potential of Lipid-Extracted Chlorella vulgaris Residue for Yarrowia lipolytica Growth at Different pH Levels

Projections show that the cultivation of microalgae will extend to the production of bio-based compounds, such as biofuels, cosmetics, and medicines. This will generate co-products or residues that will need to be valorized to reduce the environmental impact and the cost of the process. This study explored the ability of lipid-extracted Chlorella vulgaris residue as a sole carbon and nitrogen source for growing oleaginous yeasts without any pretreatment. Both wild-type Yarrowia lipolytica W29 and mutant JMY3501 (which was designed to accumulate more lipids without their remobilization or degradation) showed a similar growth rate of 0.28 h⁻¹ at different pH levels (3.5, 5.5, and 7.5). However, the W29 cell growth had the best cell number on microalgal residue at a pH of 7.5, while three times fewer cells were produced at all pH levels when JMY3501 was grown on microalgal residue. The JMY3501 growth curves were similar at pH 3.5, 5.5, and 7.5, while the fatty-acid composition differed significantly, with an accumulation of α-linolenic acid on microalgal residue at a pH of 7.5. Our results demonstrate the potential valorization of Chlorella vulgaris residue for Yarrowia lipolytica growth and the positive effect of a pH of 7.5 on the fatty acid profile.     

Detection and characterization of Shiga toxin-producing Escherichia coli in captive non-domestic mammals

Shiga toxin producing-Escherichia coli (STEC) is an important emerging pathogen, and ruminants are recognized as their main natural reservoir. The aim of this work was to establish the frequency of STEC in non-domestic mammals of the Zoo and Botanical Garden of La Plata City, Argentina, and to pheno-genotypically characterize STEC isolates. By polymerase chain reaction (PCR), Shiga toxin (stx) gene sequences were detected in 50.8% of 65 fecal samples. Twenty-five STEC strains were isolated from 38.5% of the Zoo's animals. Ten species of order Cetartiodactyla and one species of order Rodentia were recognized as new STEC carriers. STEC strains belonged to 7 different serotypes including new serotypes O12:H25 and O13:H6. Serotype O146:H28, previously associated with human infections, represented 24% of STEC isolates. The most frequent Shiga toxin identified were type 1c and type 2c. Nineteen strains were positive for iha gene, 8 strains were positive for ehxA gene. Moreover, all strains were positive for lpfAO113 and negative for rfbO157, eae, saa, lpfAO157/OI-141, lpfAO157/OI-154, efa1, and toxB genes. Results obtained by XbaI-pulsed-field gel electrophoresis (XbaI-PFGE) confirmed the transmission of STEC strains among different animal species and suborders. In addition, we observed a potential association between STEC-harboring animal and factors such as belonging to order Cetartiodactyla, living in a pit, and belonging to a non-autochthonous species. This is the first work developed with zoological mammals and STEC in Argentina.     

Effect of cutting and vacuum cleaning on the digestibility of oats by horses

Three mature Quarter Horse geldings were used in 2 Latin square experiments to measure the effect of cutting and vacuum cleaning of oats on digestibility. The horses were fed at the maintenance level of digestible energy (DE) as recommended by the NRC.¹²The data were analyzed by Latin square analysis of variance, and Tukey's t test was used to determine any differences between specific means.No significant differences among treatments were observed during either experiment, indicating that the digestibility of nutrients from oats was not affected by cutting and vacuum cleaning. Differences in the digestibility of the ether extract (EE) fraction between periods of experiment 1 were noted.     

Effect of sex, age, number of bronchoalveolar lavages and quantitation methods on the bronchoalveolar cell counts in rats.

This study was conducted to investigate the effect of sex, age, number of bronchoalveolar lavages and method of quantitation on the number of bronchoalveolar cells in rats. Forty Long Evans rats were divided into four age-sex subgroups of ten animals each. Nine consecutive bronchoalveolar lavages were done in every rat and the number of bronchoalveolar cells/mL in lavages 1-3 (L1), 4-6 (L2) and 7-9 (L3) were determined by hemocytometer and electronic cell counts (Coulter Counter). The sex or age of the rats did not show a significant effect (p less than 0.05) in the number of bronchoalveolar cells recovered from the lungs; however, there was a significant difference (p less than 0.05) in the number of cells/mL among lavages 1-3, 4-6 and 7-9 (L1 approximately equal to L2 greater than L3). A discrepancy of approximately 8% in the counts of bronchoalveolar cells was found between the hemocytometer and the Coulter Counter; however, these two methods of cell quantitation showed a significant (p less than 0.01) positive correlation (r = 0.89). No significant (p greater than 0.05) differences were found in the percentage of fluid recovery (overall mean = 94.5%) among lavages L1, L2 and L3. It was concluded that the electronic cell counting of bronchoalveolar cells is as reliable as manual counting. Although sex or age did not significantly affect the number of cells recovered from the lung, caution should be used in the number of lavages done per rat since this variable may significantly affect the results.     

Estimation du stock semencier dans le cadre d'un essai étudiant l'influence de systémes culturaux sur l'évolution de la flore adventice

Estimation of seed stock during a trial study of the influence of cultural systems on the development of the weed flora Twelve plots (12 × 20 m) were sampled at the En Crambade inter-institute station in 1984 before a 9-year trial (3×3 year rotations) was begun to study the influence of weed control methods, soil cultivation and crop rotation on the development of the weed flora. Three hundred cores, 25 per plot, were analysed separately. The weed species were identified and classified in accordance with their size and distribution. Sampling error as a function of the number of cores sampled, the variation and the average number of seeds per core were calculated.     

Nasal lesions in rats exposed to hydrogen sulfide for four hours

Fischer-344 rats were exposed for 4 hours to 0, 14, 280, or 560 mg of hydrogen sulfide.m-3 and killed 1, 18, or 44 hours later. We evaluated the nasal epithelial cells and determined the anatomic distribution of lesions. Inhalation of 560 mg of hydrogen sulfide.m-3 induced necrosis and exfoliation of respiratory and olfactory mucosal cells, but not squamous epithelial cells. The anatomic distribution of lesions was midway along the nasal passages involving nasal and maxillary conchae, but not ethmoidal conchae. Injured respiratory mucosa repaired rapidly, whereas olfactory mucosa continued to exfoliate at 44 hours after exposure.     

Cronología de Osificación Postnatal del Autópodo Torócico en el Gato Siamés (Felis catus L.)*

Chronology of the postnatal ossification of the Thoracic autopodo in the Siam cat (Felis catus L.) A study was done by radiological techniques to show the chronology of ossification of the thoracic autopodo of the Siam cat from birth up to the 25th week of postnatal development. For this experiment we used 40 little cats (19 males and 21 females) belonging to 11 litters subjected to different controls: pattern race, healthy, feeding, grow up and radioactivity. The time of the appearance and evolution of the centres that form the basipodo, metapodo and acropodo of the thoracic limb is determined. Likewise it is analized the phenomenon of fusion during that time to define the main ossification sequence in the carpo. The aspects of the postnatal ossification of the thoracic autopodo in the Siam cat are compared with the literature of differents authors about the common cat.