Enzyme Bioprospection of Marine-Derived Actinobacteria from the Chilean Coast and New Insight in the Mechanism of Keratin Degradation in Streptomyces sp. G11C

Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes—Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes.     

3种海绵中的甘露聚糖专一性凝集素

在3种海绵(Myxilla incrustans,Codosphaera sp．,Biemrta variantia)中发现了与甘露聚糖结合的专一性凝集素,甘露聚糖的甘露糖残基是通过α(1→2)和α(1→6)相互联接的。对3种海绵凝集素的血凝抑制测试的结果表明,对于海绵Myxilla incrustarts凝集素而言,猪腺体糖蛋白、脱酸猪腺体糖蛋白、胎球蛋白和脱酸胎球蛋白都是比较好的抑制剂;对于海绵Coelosphaera sp．凝集素而言,仅猪腺体糖蛋白是有效的抑制剂;而对海绵Biemna variantia凝集素来说,猪腺体糖蛋白和脱酸猪腺体糖蛋白是有效的抑制剂。这3种凝集素对自然的和用胰蛋白酶消化后的人体红细胞(B型)都有很好的凝集作用,它们的血凝活性不依赖钙离子的存在。     

Tolerance of benzalkonium chloride, formalin, malachite green, and potassium permanganate in goldfish and zebrafish

OBJECTIVE: To determine tolerance of goldfish and zebrafish to benzalkonium chloride, formalin, malachite green, and potassium permanganate. DESIGN: Tolerance study. ANIMALS: Adult goldfish (Carassius auratus) and zebrafish (Danio rerio). PROCEDURES: Groups of fish (n = 10/group) were exposed to each disinfectant at the therapeutic dosage; at 0.25, 0.5, 3, and 5 times the concentration used for the therapeutic dosage; and at the concentration used for the therapeutic dosage but for 3 or 5 times the recommended exposure time. RESULTS: In both species, exposure to malachite green at the therapeutic dosage resulted in toxic effects, including death. Exposure to formalin at the therapeutic dosage resulted in toxic effects in goldfish, but not zebrafish, and exposure to potassium permanganate resulted in toxic effects in zebrafish, but not goldfish. On the basis of the ratio of therapeutic dosage to median lethal dosage, in goldfish, formalin was more toxic than benzalkonium chloride, which was more toxic than malachite green, which was more toxic than potassium permanganate. In zebrafish, potassium permanganate was more toxic than formalin and benzalkonium chloride, which were approximately equally toxic and more toxic than malachite green. Extending treatment time increased the toxicity of potassium permanganate in zebrafish and the toxicity of formalin and malachite green in goldfish, but did not alter the toxicity of the other disinfectants. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that there was no consistency between zebrafish and goldfish in their tolerance to disinfectants, and that therapeutic dosages reported in the literature for these disinfectants were not always safe.     

Detection and characterization of a rhabdovirus causing mortality in black bullhead catfish,Ameiurus melas

This study fully describes a severe disease outbreak occurred in 2016 in black bullhead catfish farmed in Italy. Affected fish showed nervous clinical signs as well as emaciations and haemorrhagic petechiae on the skin at the fin bases, abdomen and gills. Viral isolation in cell culture allowed the subsequent identification of a rhabdovirus, tentatively named ictalurid rhabdovirus (IcRV), through electron microscopy, immunofluorescence and whole genome sequencing (WGS). The newly isolated virus, together with 14 additional viral strains stored in our repository and detected during similar mortality episodes in the period 1993–2016, was phylogenetically analysed on the basis of the nucleoprotein and the glycoprotein nucleotide and amino acid sequences. The genetic distances among Italian IcRV strains were also estimated. Our results show that all the IcRV strains belong to the genus Sprivivirus and are closely related to the tench rhabdovirus (TenRV). Italian catfish production is constantly decreasing, mainly due to viral infections, which include the newly characterized IcRV. Data presented in this work will assist to investigate the molecular epidemiology and the diffusive dynamics of this virus and to develop adequate surveillance activities.     

Near and Mid Infrared Spectroscopy to Detect Malolactic Biotransformation of Oenococcus oeni in a Wine-Model

The aim of this work was to verify the potential of infrared （IR） spectroscopy in near and mid regions to detect the beginning of the malolactic fermentation （MLF） occurring in a model-wine and the further cells autolysis. MLF in wine is a secondary biotransformation due to lactic acid bacteria that usually occurs spontaneou,;ly or after starter inoculation at the end of alcoholic fermentation. Nowadays, it is desirable to supply winemakers with a new rapid and non-destructive approach to monitor MLF progress and 1R spectroscopy technology appears to be suitable for this purpose. The transformation of L-malic acid into L-lactic acid was carried out by inoculating a synthetic wine with an Oenococcus oeni culture and it was monitored through microbiological and chemical methods. At the same time, Fourier transform near infrared （FT-NIR） spectral data, in diffusive transflection mode using an optic probe, and FT-IR spectra, using an germanium crystal attenuated total reflectance （ATR） cell, were collected. Principal component analysis of the spectra was able to identify absorption bands related to the key molecular modifications that took place during the L-malic acid transformation. Thus, the samples were discriminated according to the fermentation phase. Although this study is a preliminary approach, results confirm that near infrared （NIR） and mid infrared （MIR） spectroscopy could be successfully applied to detect the start of MLF and the autolysis of the lactic acid bacteria （LAB） cells.     

生物强化处理油田含油污泥的试验研究

采用油泥、菌剂及其他添加物充分混合后堆放的方法,进行了3种条件下的微生物对含油污泥的强化分解研究。结果表明,在菌剂和锯末的共同作用下,经过45d后,污泥含油量从24%下降到11%,去除率达到54%;而菌剂单独作用下,含油量下降到16%,去除率达为33%;在没有菌剂作用下,含油量仍然保持在20%以上。对处理过程中pH变化特性进行了研究。试验说明,生物强化分解是含油污泥处理的有效途径。     

Behind the Pan‐European Convergence Path: The Role of Innovation,Specialisation and Socio‐economic Factors

The paper analyses the determinants of regional disparities in per capita gross domestic product (GDP) and their evolution over time in the enlarged European Union (EU). With reference to the literature it groups EU regions on the basis of three different factors—specialisation, socio‐economic features, and innovation. It then analyses regional disparities in per capita GDP (EU‐relative and country‐relative) across groups over 2004–2011 using both non‐parametric tools and traditional regression analysis with spatial effects. The paper finds that EU‐wide convergence actually conceals growing divergence across old member regions and within new members. Coming to the factors that lie at the heart of regional disparities, country factors lose importance for newcomers but become more important for older members, notwithstanding longstanding integration. Socio‐economic factors and innovation instead become increasingly important for all areas, socio‐economic factors lying at the heart of within‐country differences and innovation more of those between regions. Finally, specialisation appears to have a lower explanatory power.     

Actor-Network-Theory perspective on a forestry decision support system design

Use of decision support systems (DSS) has thus far been framed as a social process of adoption or technical process of usability. We analyze the development of a DSS as a process of institutionalization of new as well as drift of existing practices. We write an Actor-Network-Theory (ANT) account, i.e. an interpretive study, that follows the traces left by both human and non-human actors (e.g. technology, methodologies, etc.) to understand how a DSS development project institutionalizes DSS technology in several forest management organizations in the German state of Rheinland Pfalz. The research has an innovative value since it uses ANT in the design of a DSS, hence affecting it, while commonly ANT has been used to understand why networks work or do not. Moreover, we use a new technology (PREZI^TM, www.prezi.com) for the visualization of the whole actor network coherent to the ANT methodology, i.e. “keeping the social flat.” As a result, the development of the ANT account proposed in the present paper, even if still partial, supports the design of new technologies being introduced in current practice and generates an important learning effect thanks to the underpinning interpretative approach.