Über den angeblichen Einfluss von frischem grünem Futter auf den Farbwechsel von Acrida turrita

Zusammenfassung Gelbe Acrida turrita-Larven, welche in der Dunkelkammer auf grünem wachsendem Gras gezüchtet wurden, wurden niemals unter dem Einfluß des frischen grünen Futters nach der Häutung grün, sondern behielten ihre Färbung bei.Gelbe Acrida turrita-Larven, denen wachsendes grünes Futter in einem großen Käfig zur Verfügung stand, wurden bei genügend langem Aufenthalt nach der Häutung der Farbe des Käfigs entsprechend grau aber niemals grün.Aus diesen Versuchen wurde geschlossen, daß beim Grünwerden der gelben Acrida-Larven wachsende und grüne Putter nicht von Bedeutung ist.     

Effect of 24-epibrassinolide on biomass, growth and free proline concentration in Spirulina platensis (Cyanophyta) under NaCl stress

In this study, biomass, growth and free proline concentration were investigated in Spirulina platensis treated with different concentrations of NaCl (50, 100, 150, and 200 mM) and 24-epibrassinolide (24-epiBL) hormone (0.5, 1.0, and 3.0 μM) over 5 days. As a result of analysing the cultures under salinity stress, it was determined that biomass and growth rate decreased significantly, while proline concentration increased considerably under salinity stress. The increase in the concentration of proline suggests a role in response to NaCl stress. Among the cultures treated with different concentrations of 24-epiBL, maximum growth was determined at the cultures at 1.0 μM 24-epiBL. Algal growth was also greater at the 0.5 and 3.0 μM concentrations of 24-epiBL with respect to control cultures. With respect to control, 24-epiBL affected growth rate and biomass positively, but proline concentration did not change. Among the cultures supplied with different combinations of NaCl and 24-epiBL, growth rate increased in 150/0.5 and 150/3.0 mM/μM concentrations, but was maximal for the culture containing 150/1.0 mM/μM combination. The increase in algal growth suggests a role for 24-epiBL in partially alleviated to NaCl stress. These results suggest that 24-epiBL may have a protective role for S. platensis reducing the inhibitor effects of salinity stress.     

Fatty acid composition and biogenic amines in acidified and fermented fish silage: a comparison study

In the presented study, ensiling of discard fish by acidification or fermentation was evaluated. Klunzinger’s ponyfish which is a discard fish was used for the production of fish silage by acidification (3% formic acid for Method FA; 1.5% formic and 1.5% sulphuric acid for Method FASA) and fermentation (Lactobacillus plantarum for Method LP and Streptococcus thermophilus for Method ST). The chemical, microbiological and nutritional properties of the differently preserved fish silages were estimated during a storage period of 60 d at ambient temperature. Compared to the raw material, a slight increase in saturated fatty acids and a slight decrease in polyunsaturated fatty acids were observed in all silages. At the end of the storage period, the aerobic bacteria counts after applying Methods FA, FASA, LP and ST amounted to 2.35, 2.39, 5.77 and 5.43 log cfu/g, respectively. The analysis of thiobarbituric acid revealed that acidification of silages accelerated the lipid oxidation. Nine biogenic amines were found in raw fish and different silages. The initial histamine concentration in raw fish was 0.17 mg/100 g and in all silages it remained at low levels during the storage period. The initial tyramine content was found to be 1.56 mg/100 g in raw fish and increased significantly in all silages. The increase of the tyramine content in fermented silages was considerably higher than in acidified silages (23–48 mg/100 g and 5–10 mg/100 g, respectively). It can be concluded that acidified or fermented fish silage should be considered as potential feed component for animals because of its high nutritional value and appropriate microbiological and chemical quality.     

Discovery of an acidic,thermostable and highly NADP<Superscript>+</Superscript> dependent formate dehydrogenase from <Emphasis Type="Italic">Lactobacillus buchneri</Emphasis> NRRL B-30929

Objectives

To identify a robust NADP⁺ dependent formate dehydrogenase from Lactobacillus buchneri NRRL B-30929 (LbFDH) with unique biochemical properties.

Results

A new NADP⁺ dependent formate dehydrogenase gene (fdh) was cloned from genomic DNA of L. buchneri NRRL B-30929. The recombinant construct was expressed in Escherichia coli BL21(DE3) with 6?×?histidine at the C-terminus and the purified protein obtained as a single band of approx. 44 kDa on SDS-PAGE and 90 kDa on native-PAGE. The LbFDH was highly active at acidic conditions (pH 4.8–6.2). Its optimum temperature was 60 °C and 50 °C with NADP⁺ and NAD⁺, respectively and its T_m value was 78 °C. Its activity did not decrease after incubation in a solution containing 20% of DMSO and acetonitrile for 6 h. The K_M constants were 49.8, 0.12 and 1.68 mM for formate (with NADP⁺), NADP⁺ and NAD⁺, respectively.

Conclusions

An NADP⁺ dependent FDH from L. buchneri NRRL B-30929 was cloned, expressed and identified with its unusual characteristics. The LbFDH can be a promising candidate for NADPH regeneration through biocatalysis requiring acidic conditions and high temperatures.

     

Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next‐generation sequencing

The Atlantic bluefin tuna is a highly migratory species emblematic of the challenges associated with shared fisheries management. In an effort to resolve the species’ stock dynamics, a genomewide search for spatially informative single nucleotide polymorphisms (SNPs) was undertaken, by way of sequencing reduced representation libraries. An allele frequency approach to SNP discovery was used, combining the data of 555 larvae and young‐of‐the‐year (LYOY) into pools representing major geographical areas and mapping against a newly assembled genomic reference. From a set of 184,895 candidate loci, 384 were selected for validation using 167 LYOY. A highly discriminatory genotyping panel of 95 SNPs was ultimately developed by selecting loci with the most pronounced differences between western Atlantic and Mediterranean Sea LYOY. The panel was evaluated by genotyping a different set of LYOY (n = 326), and from these, 77.8% and 82.1% were correctly assigned to western Atlantic and Mediterranean Sea origins, respectively. The panel revealed temporally persistent differentiation among LYOY from the western Atlantic and Mediterranean Sea (F_ST = 0.008, p = .034). The composition of six mixed feeding aggregations in the Atlantic Ocean and Mediterranean Sea was characterized using genotypes from medium (n = 184) and large (n = 48) adults, applying population assignment and mixture analyses. The results provide evidence of persistent population structuring across broad geographic areas and extensive mixing in the Atlantic Ocean, particularly in the mid‐Atlantic Bight and Gulf of St. Lawrence. The genomic reference and genotyping tools presented here constitute novel resources useful for future research and conservation efforts.     

Investigation of gastrin-releasing peptide as a mediator for 5'-guanidinonaltrindole-induced compulsive scratching in mice

Gastrin-releasing peptide (GRP) has been implicated in the itch-scratch cycle. We investigated if this gut-brain-skin peptide plays a role in the compulsive, hindleg scratching of the neck of mice by 5′-guanidinonaltrindole (GNTI), the kappa opioid receptor antagonist, and in the antipruritic activity of nalfurafine, the kappa opioid agonist. Previously, we showed that GNTI (0.03-1 mg/kg, s.c.) elicits dose-related scratching and that nalfurafine (0.001-0.02 mg/kg, s.c.) inhibits this behavior in mice. Utilizing immunohistochemistry, GRP positive nerve fibers were detected in mouse skin and superficial layer of the dorsal horn of the spinal cord as well as GRP positive cells in the dorsal root ganglion. Pretreating mice with either a pseudopeptide GRP receptor antagonist, RC-3095 (10-30 mg/kg, s.c. at −15 min), or a peptide GRP receptor antagonist, [d-Phe⁶]bombesin(6-13) methyl ester (2-100 nmol, i.t. at −10 min), did not suppress GNTI-induced scratching. However, pretreating mice with either antagonist inhibited scratching precipitated by the GRP receptor agonist, GRP_18-27 (2 nmol, i.t.). Pretreating mice with a muscarinic M₁ receptor agonist, McN-A-343 (1.5-15 μg/5 μl, i.t. at −10 min) antagonized GNTI-induced scratching. Norbinaltorphimine (20 mg/kg, i.p. at −18 to −20 h), a kappa opioid antagonist, countered the antiscratch activity of nalfurafine. We conclude that (a) the GRP receptor system does not mediate GNTI-induced scratching and (b) the kappa opioid system is involved, at least in part, in the scratch suppressing activity of nalfurafine.     

New Nuclear SNP Markers Unravel the Genetic Structure and Effective Population Size of Albacore Tuna (Thunnus alalunga)

In the present study we have investigated the population genetic structure of albacore (Thunnus alalunga, Bonnaterre 1788) and assessed the loss of genetic diversity, likely due to overfishing, of albacore population in the North Atlantic Ocean. For this purpose, 1,331 individuals from 26 worldwide locations were analyzed by genotyping 75 novel nuclear SNPs. Our results indicated the existence of four genetically homogeneous populations delimited within the Mediterranean Sea, the Atlantic Ocean, the Indian Ocean and the Pacific Ocean. Current definition of stocks allows the sustainable management of albacore since no stock includes more than one genetic entity. In addition, short- and long-term effective population sizes were estimated for the North Atlantic Ocean albacore population, and results showed no historical decline for this population. Therefore, the genetic diversity and, consequently, the adaptive potential of this population have not been significantly affected by overfishing.