Heterologous expression of type I antifreeze peptide GS-5 in baker's yeast increases freeze tolerance and provides enhanced gas production in frozen dough

The demand for frozen-dough products has increased notably in the baking industry. Nowadays, no appropriate industrial baker's yeast with optimal gassing capacity in frozen dough is, however, available, and it is unlikely that classical breeding programs could provide significant improvements of this trait. Antifreeze proteins, found in diverse organisms, display the ability to inhibit the growth of ice, allowing them to survive at temperatures below 0 degrees C. In this study a recombinant antifreeze peptide GS-5 was expressed from the polar fish grubby sculpin (Myoxocephalus aenaeus) in laboratory and industrial baker's yeast strains of Saccharomyces cerevisiae. Production of the recombinant protein increased freezing tolerance in both strains tested. Furthermore, expression of the GS-5 encoding gene enhanced notably the gassing rate and total gas production in frozen and frozen sweet doughs. These effects are unlikely to be due to reduced osmotic damage during freezing/thawing, because recombinant cells showed growth behavior similar to that of the parent under hypermosmotic stress conditions.     

Chemical composition and insecticidal activity of essential oils from Vanillosmopsis pohlii baker against Bemisia argentifolii

Essential oils from the heartwood and leaves of specimens of Vanillosmopsis pohlii collected in two different localities were analyzed by GC-MS. The major constituent of both heartwood essential oils was the sesquiterpene alpha-bisabolol. Essential oil composition from leaves was quite different for two specimens and showed beta-pinene and E-caryophyllene as principal constituents. The essential oil of heartwood and the pure sesquiterpene alpha-bisabolol were tested against Bemisia argentifolii, the white fly fruit plague, and pronounced insecticidal effects were observed.     

Pond management and water quality for drip irrigation in Mediterranean intensive horticultural systems

The influence of pond management on water quality for drip-irrigated crops was studied throughout a field survey and a mesocosm experiment. Water sources were pooled into two groups: ground or surface water (GW/SW) and recycled wastewater. Pond covering, which was limited to about a quarter of them, improved water quality by reducing phytoplankton biomass. However, biocide applications and pond dredging were ineffective at improving in-pond water quality. Dredging did not reduce the concentrations of planktonic chlorophyll a or total suspended solids (TSS) in GW/SW fed ponds, whereas biocide applications increased both parameters. Field and experimental data proved that the two predominant taxa of submerged aquatic vegetation (SAV) found in ponds (Potamogeton pectinatus and Chara spp.) improved water quality by increasing water oxygenation and decreasing chlorophyll a and TSS concentrations. Preserving SAV (especially Chara spp.) appears to be an environment-friendly, cost-effective and recommendable alternative strategy for irrigation pond management.     

Use of three fodder trees in the feeding of goats in the subhumid tropics in Mexico

Chemical composition, in vitro gas production with and without polyethyleneglycol (PEG-4000 MW), and in vitro digestibility of dry matter (IVDMD) and organic (IVOMD) foliage from Pithecellobium dulce, Gliricidia sepium and Haematoxylum brasiletto were determined. The preference test was run for 15 days: the first 10 days as adaption period and the 5 days served as evaluation period. It was conducted in ten developing female Creole goats of 6 months old, weighing 14?±?2.0 kg in order to determine goat preference for any of the three foliages. Productive performance of 35 male creole kids of 6 months old (14?±?3.0 kg) was also determined by ad libitum feeding of the foliage of the tree: the 30 and 15 % of each of the P. dulce (T1, T2), G. sepium (T3, T4), and H. brasiletto (T5, T6) foliages were added to the experiment diets, while T7 served as control diet that did not contain any foliage. The crude protein (CP), total phenols (TP), condensed tannins (CT), IVDMD, and IVOMD were different among the foliages. The PEG determined the biological activity of the TP and CT of H. brasiletto. Goats preferred to consume the foliage of P. dulce because of its higher content of CP and IVDMD and low content of TP and CT. In the productive response, dry matter intake (DMI) was higher in kids fed T1 diet and was stimulated by higher IVDMD and IVOMD, which resulted in the higher daily weight gain (DWG). The contribution with TP and CT of H. brasiletto to T5 and T6 and the rejection by the animals of G. sepium in T3 and T4 explain the negative effects on the DMI and the DWG. Findings of the study suggested higher kid performance for P. dulce foliage. Possible attributes may include its better CP, low TP and CT, and higher digestibility.     

A Survey of Logger Concerns When Working with Small Woodland Owners

Many small woodland owners will harvest timber only once in their lifetime. Their expectations of a logging operation do not often match with reality. On the other side of the equation, loggers express frustration when working with small woodland owners. The jobs are smaller and often come with complications not found with industrial forest owners. Adding to this is the fact that the two parties often aren’t speaking the same language. In order to better prepare landowners for this operation, we surveyed logging contractors to learn about the interactions with small woodland owners in Oregon, USA. The mail survey focused on how jobs were bid, use of contracts, and difficulties that loggers had when working with small woodland owners. Results provide information that confirms the challenges present when working with many individual owners who do not have experience with harvest operations. Survey results also confirm that the logging workforce in Oregon is aging on average. Results showed no correlation between the number of years working as a logger and responses to other questions.     

The role of rodents in avian influenza outbreaks in poultry farms: a review

Wild migratory birds are associated with global avian influenza virus (AIV) spread. Although direct contact with wild birds and contaminated fomites is unlikely in modern non-free range poultry farms applying biosecurity measures, AIV outbreaks still occur. This suggests involvement of other intermediate factors for virus transmission between wild birds and poultry. This review describes current evidence of the potential role of rodents in AIV transmission from wild birds to poultry and between poultry houses. Rodents can be abundant around poultry houses, share their habitat with waterfowl and can readily enter poultry houses. Survival of AIV from waterfowl in poultry house surroundings and on the coat of rodents suggests that rodents are likely to act as mechanical vector. AIVs can replicate in rodents without adaptation, resulting in high viral titres in lungs and nasal turbinates, virus presence in nasal washes and saliva, and transmission to naïve contact animals. Therefore, active AIV shedding by infected rodents may play a role in transmission to poultry. Further field and experimental studies are needed to provide evidence for a role of rodents in AIV epidemiology. Making poultry houses rodent-proof and the immediate surroundings unattractive for rodents are recommended as preventive measures against possible AIV introduction.     

Production of diatom–bacteria biofilm isolated from Seriola lalandi cultures for aquaculture application

Controlled incorporation of selected microalgae and bacteria in aquaculture systems can be beneficial because they can act as microbiological control. That is why the characteristics of biofilm generated naturally in Seriola lalandi culture cages were analysed, their potential benefit to the growth of larvae was studied, and their controlled use for improving the larval viability and as a vector to improve incorporation of previously studied probiotic bacteria was tested. According to biodiversity results, these biofilms are composed of a diatom–bacteria mix showing a decrease in biodiversity in laboratory culture conditions being dominated by Navicula phyllepta and bacteria of the family Rhodobacteraceae. This can be produced on mesh substrates incorporated in bioreactors with rapid growth rate and adhesiveness. Preliminary results from the addition of substrates with this specific biofilm in larvae culture systems showed that it is consumed by the larvae without negative effects, while positive effects on the viability of larvae in combination with probiotics were observed. Considering preliminary results, the addition of these specific substrates with diatom–bacteria biofilms could be a good improvement for aquaculture systems and together with the use of probiotics can contribute to maintaining a stable and controlled system improving the viability of the larval fish culture in its early stages.     

Changes in Biochemical Compositions and Quality of White Shrimp (Litopenaeus vannamei) During Storage

ABSTRACT

To understand biochemical characteristics, storage stability, and freshness indicators of white shrimp (Litopenaeus vannamei), changes in extractable nitrogenous compounds, microbial count, and sensory rating of white shrimp during storage at 25 and 4°C were investigated. Free amino acids showed a slow increase during storage at 25°C, but no obvious change was found at 4°C. Adenosine triphosphate (ATP) and adenosine diphosphate (ADP) were found at initial stage and decreased rapidly after storage. Both inosine 5′-monophosphate (IMP) and adenosine monophosphate (AMP) increased and then decreased during storage. Inosine, hypoxanthine, and the K-value gradually increased with time. The levels of total volatile basic nitrogen (TVB-N), NH₃, and trimethylamine (TMA) of white shrimp increased with storage time at 25 and 4°C. The TVB-N, NH₃, TMA, inosine, hypoxanthine, and K-value could be considered as freshness indicators of white shrimp during storage. However, the total plate count did not corroborate the acceptability recommended limits for white shrimp during storage. The sensory evaluation, associated with TVB-N, TMA, and K-value, showed the quality was unacceptable after 6 h storage at 25°C and 7 days at 4°C.     

Optimum nitrogen fertilization rates for second-year corn succeeding alfalfa under irrigation

The N contribution of alfalfa (Medicago sativa L.) to the succeeding corn (Zea mays L.) crop (FYC) is widely recognized. However, there is less information regarding the optimum N fertilization rates (ONR) for a second-year corn (SYC) following alfalfa. Thus, the objective of this study was to evaluate the response of SYC after alfalfa to N fertilization under irrigated semiarid conditions. Three field experiments of SYC following alfalfa were conducted between 2007 and 2009 in Northeast Spain. Treatments included the combination of six N rates applied to FYC (0, 50, 100, 150, 200, and 300 kg N ha⁻¹) with four N rates applied to SYC (0, 100, 200, and 300 kg N ha⁻¹). In one of the three fields, high SYC yields (16.8 Mg ha⁻¹) were obtained in plots that remained unfertilized during two consecutive years after alfalfa. On the other two fields, 81-100% of the maximum corn yields were obtained with application of 200 kg N ha⁻¹ to SYC. Results suggest that the typical N fertilizer rates applied to SYC after alfalfa in irrigated semiarid areas (300 kg N ha⁻¹) could be reduced by at least 100 kg N ha⁻¹, with small or no economic penalties and important reductions in N losses.     

Metabolites involved in oleuropein accumulation and degradation in fruits of Olea europaea L.: Hojiblanca and Arbequina varieties

The biosynthetic pathway of oleuropein (from 7-ketologanin, oleoside-11-methyl ester, 7-β-1-d-glucopyranosyl-11-methyl oleoside, and ligstroside to oleuropein) was investigated in two fruit species of Oleaceae, namely, Arbequina and Hojiblanca. Main oleuropein precursors and their metabolites, produced by the enzymatic hydrolysis mediated by β-glucosidase, were identified and quantified to establish the oleuropein transformation pathway. Changes in the concentration of these compounds were measured by direct control of in vivo fruit tissue during their ripening. High contents of aglycones at the initial stage of the process were caused by the high activity of β-glucosidase, which supports that oleuropein biosynthesis is coupled with enzymatic hydrolysis, producing its aglycone form. The low oleuropein content at this initial stage was caused by the imbalance between catabolic and anabolic pathways, favoring the former ones. Once the main polyphenol synthesis phase was completed, the biosynthetic capacity diminished and the content of all compounds decreased. Mass balance revealed that precursors of oleuropein, which are rapidly transformed by β-glucosidase and esterases, scarcely contributed to the accumulation of oleuropein. The biosynthetic pathway proposed by Damtoft applies for both varieties, but our study reveals that the β-glucosidase enzyme is involved in oleuropein synthesis. This enzyme shows high substrate specificity to oleuropein, which consequently is degraded to its aglycone form, with diminished efficacy of oleuropein biosynthesis. Different enzymatic activities of varieties will result in oleuropein accumulation and metabolic transformation of phenols.