Body mass changes in Brünnich's guillemots Uria lomvia with age and breeding stage

Body mass of Brünnich's guillemots Uria lomvia breeding at Coats Island, Canada, was measured during incubation and chick-rearing in 1988–2001. In most years, mass increased during incubation and fell after hatching, leveling off by the time chicks were 18 d old, close to the age at which chicks departed. Mass during incubation increased with age up to about 12 yr, but the mass of birds brooding chicks was not related to age. The trend towards increasing mass during incubation was mainly a consequence of mass increases of young breeders as older birds maintained a constant mass. The variation in adult mass with age during incubation seems likely to reflect age-related variation in foraging ability, but the loss of mass after hatching, being greater for older birds, appears best explained as a response to the demands of provisioning chicks, with older birds transferring their accumulated reserves to their chicks via higher provisioning rates.     

Fatty acid signatures of stomach oil and adipose tissue of northern fulmars (<Emphasis Type="Italic">Fulmarus glacialis</Emphasis>) in Alaska: implications for diet analysis of Procellariiform birds

Procellariiforms are unique among seabirds in storing dietary lipids in both adipose tissue and stomach oil. Thus, both lipid sources are potentially useful for trophic studies using fatty acid (FA) signatures. However, little is known about the relationship between FA signatures in stomach oil and adipose tissue of individuals or whether these signatures provide similar information about diet and physiology. We compared the FA composition of stomach oil and adipose tissue biopsies of individual northern fulmars (N = 101) breeding at three major colonies in Alaska. Fatty acid signatures differed significantly between the two lipid sources, reflecting differences in dietary time scales, metabolic processing, or both. However, these signatures exhibited a relatively consistent relationship between individuals, such that the two lipid sources provided a similar ability to distinguish foraging differences among individuals and colonies. Our results, including the exclusive presence of dietary wax esters in stomach oil but not adipose tissue, are consistent with the notion that stomach oil FA signatures represent lipids retained from prey consumed during recent foraging and reflect little metabolic processing, whereas adipose tissue FA signatures represent a longer-term integration of dietary intake. Our study illustrates the potential for elucidating short- versus longer-term diet information in Procellariiform birds using different lipid sources.     

Toxic effects of acrylic acid on Clostridium propionicum and isolation of acrylic acid‐tolerant mutants for production of acrylic acid

This work presents a systematic investigation of the toxic effects of acrylic acid on the growth of Clostridium propionicum and the isolation of acrylic acid‐tolerant mutants. The results suggest that addition of acrylic acid prolonged the lag phase of the fermentation and reduced the initial‐specific growth rate, as well as the final cell concentration. Moreover, the toxic effect of acrylic acid was sensitive to the pH value. The minimal inhibition concentration of acrylic acid increased from 1.11 to 31.25 mM when the pH value rose from 5.8 to 7.4. In addition, the molar concentration ratio of products (acetic acid:propionic acid) was enhanced with the supplementation of acrylic acid. The highest ratio was 0.7:1 when acrylic acid was 20.83 mM at pH 7.4. Two acrylic acid‐tolerant mutants were isolated, which could still grow at a high concentration (43.06 mM) of acrylic acid. These strains could be instrumental for improved bioproduction of acrylic acid.     

Amino acid composition of human and guinea pig blood proteins,and ovarian proteins of the yellow fever mosquito Aedes aegypti; and their effects on the mosquito egg production

• 1.1. Amino acid composition of human and guinea pig blood proteins, and ovarian proteins of the yellow fever mosquito Aedes aegypti was analyzed.
• 2.2. The lower isoleucine content in human hemoglobin possibly caused the lower egg production by A. aegypti following feeding on human than guinea pig blood.
• 3.3. Supplementation of human red blood cell or whole blood with isoleucine resulted in a greater egg production per mg of ingested medium than when fed human red blood cell or whole blood alone.

     

Fatty acid composition of sprat (<Emphasis Type="Italic">Sprattus sprattus</Emphasis>) and herring (<Emphasis Type="Italic">Clupea harengus</Emphasis>) in the Baltic Sea as potential prey for salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>)

Sprat (Sprattus sprattus) and small herring (Clupea harengus) are the dominant prey fish of Atlantic salmon (Salmo salar) in the Baltic Sea. If the fatty acid (FA) proportions of sprat and herring differ, the dietary history of ascending salmon could be determined from their FA profiles. Therefore, we investigated the FA composition of several age groups of whole sprat and small herring, caught from the three main feeding areas of salmon in autumn and spring. Oleic acid (18:1n-9) was the most prevalent FA in sprat and characteristic of this species. In herring, palmitic acid (16:0) was the most common FA, but herring lipid was characterized by n-6 polyunsaturated FAs, and moreover, by palmitoleic acid (16:1n-7) and vaccenic acid (18:1n-7). Due to the higher lipid content of sprat, the concentrations of all other FAs, excluding these, were higher in sprat than in herring. The concentration of docosahexaenoic acid (DHA, 22:6n-3) increased with an increase in the lipid content and was consequently highest in the youngest specimens, being in young sprat almost double that of young herring, and 2.6 times higher in the sprat biomass than in that of herring. As a result of a decrease in the DHA concentration with age, the ratio thiamine/DHA increased with respect to age in both species, and was lower in sprat than in herring. It is concluded that an abundance of DHA in the diet of salmon most likely increases oxidative stress because of the susceptibility of DHA to peroxidation, and thus decreases thiamine resources of fasting, prespawning salmon. Because the FA composition of sprat and herring differs, and the relative abundancies of prey fish differ between the feeding areas of salmon, the feeding area of ascending salmon can most probably be derived by comparing their FA profiles.     

The use of immobilized Saccharomyces cerevisiae on radiation crosslinked acrylamide–maleic acid hydrogel carriers for production of ethyl alcohol

Radiation crosslinked acrylamide/maleic acid (AAm/MA) copolymers were prepared by γ-irradiation. They were used in experiments on swelling, diffusion, and immobilization of yeast cells (Saccharomyces cerevisiae) for the production of ethyl alcohol. AAm/MA hydrogels containing different amount of MA, irradiated at different doses, were used for swelling and diffusion studies. The parameters of swelling, diffusional exponents, network constants, diffusion coefficients and percent porosity of the hydrogel/penetrant systems were calculated and evaluated. Yeast cells were immobilized on to the hydrogels by adsorption during multiplication, and ethyl alcohol production by the hydrogels was investigated. Swelling of AAm/MA increased with increase in MA content. Ethyl alcohol production also increased with increasing MA in the hydrogels but decreased with an increase of irradiation dose.     

Metabolic engineering of a laboratory‐evolved Thermobifida fusca muC strain for malic acid production on cellulose and minimal treated lignocellulosic biomass

Malic acid is mainly used as an acidulant and taste enhancer in the beverage and food industry. Previously, a mutant strain Thermobifida fusca muC, obtained by adaptive evolution was found to accumulate malic acid on cellulose with low yield. In this study, the malic acid synthesis pathway in T. fusca muC was confirmed to be from phosphoenolpyruvate to oxaloacetate, followed by reduction of oxaloacetate to malate. To increase the yield of malic acid by the muC strain significantly, the carbon flux from pyruvate was redirected to oxaloacetate by expressing an exogenous pyruvate carboxylase (PCx) gene from Corynebacterium glutamicum ATCC 13032 in the chromosome of T. fusca muC‐16. The yield of malic acid in the engineered strain muC‐16 was increased by 47.9% compared to the parent strain muC. The muC‐16 strain was then grown on ～100 g/L cellulose and the highest titer of malic acid was 62.76 g/L by batch fermentation. T. fusca muC‐16 strain converted milled corn stover to malic acid with the highest titer of 21.47 g/L with minimal treatment. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:14–20, 2016     

A scientific note on the evidence for the production and use of wax by a captive female <Emphasis Type="Italic">Bombus</Emphasis><Emphasis Type="Italic">sylvestris</Emphasis>

The presence of wax glands in the socially parasitic subgenus Bombus (Psithyrus) was established only recently (Sramkova and Ayasse, 2008), but the uses for the produced wax are unknown. In this investigation nest-searching Bombus sylvestris females were collected and kept in darkness, in conditions of controlled temperature and relative humidity, using rearing conditions for non-parasitic bumblebees. The results show that in Bombus sylvestris not only wax glands are present but they also can produce wax which can be used as a building material.     

Culture medium influence on growth,fatty acid,and pigment composition of <Emphasis Type="Italic">Choricystis minor</Emphasis> var. <Emphasis Type="Italic">minor</Emphasis>: a suitable microalga for biodiesel production

The purposes of this study were to assess the influence of culture medium on biomass production, fatty acid, and pigment composition of Choricystis minor var. minor and to evaluate the use of this microalga as a source of fatty raw material for biodiesel production. Cultures of C. minor var. minor were grown using WC (Wright’s cryptophyte) and BBM (Bold’s Basal medium) media. BBM medium produced more biomass (984.3 mg L^?1) compared to the WC medium (525.7 mg L^?1). Despite this result, WC medium produced a higher methyl ester yield for biodiesel production than the BBM medium (170.0 and 90.2 mg g^?1 of biomass, respectively). The average percentage of fatty acids obtained using the WC medium (17.0 %) was similar to soybean (18.0 %) and with similar biomass fatty acid profile. However, for pigment production, carotenoids and chlorophyll concentrations were twice as high when using the BBM medium.