Improved Cold and Drought Tolerance of Doubled Haploid Maize Plants Selected for Resistance to Prooxidant tert‐Butyl Hydroperoxide

To improve the abiotic stress tolerance of maize (Zea mays L.), doubled haploid (DH) plants were produced by in vitro selection of microspores exposed to tert‐butyl hydroperoxide (t‐BuOOH) as a powerful prooxidant This study investigated the tolerance of the progenies of t‐BuOOH‐selected DH lines to oxidative stress, cold and drought in controlled environment pot experiments by analyses of photosynthetic electron transport and CO₂ assimilation processes, chlorophyll bleaching and lipid peroxidation of leaves. Our results demonstrated that the t‐BuOOH‐selected DH plants exhibited enhanced tolerance not only to oxidative stress‐induced by t‐BuOOH but also to cold and drought stresses. In addition, they showed elevated activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase and glutathione S‐transferase when compared with the DH lines derived from microspores that were not exposed to t‐BuOOH and to the original hybrid plants. The results suggest that the simultaneous up‐regulation of several antioxidant enzymes may contribute to the oxidative and cold stress tolerance of the t‐BuOOH‐selected DH lines, and that the in vitro microspore selection represents a potential way to improve abiotic stress tolerance in maize.     

Removal of a metallic foreign body from the tongue of three horses

The objective of this case report is to describe the diagnostic and surgical techniques for removal of a metallic foreign body in the tongue of three adult horses. The three horses were presented for evaluation and treatment of dysphagia and marked hypersalivation of 3–5 days duration. Radiographs of the head revealed the presence of a metallic foreign body in the tongue of each horse. The foreign bodies could be precisely localised under general anaesthesia using palpation and lingual ultrasonography and/or lingual radiography in combination with a forceps as a marker. The foreign bodies were successfully removed using laparoscopic instruments creating minimal soft tissue trauma. The use of long (43 cm) small laparoscopic (5 mm) instruments enabled good visualisation of the surgical field, providing optimal conditions for successful minimally invasive surgical treatment of horses with foreign bodies in the tongue. The three horses made uneventful recoveries and 12 months after surgery were eating normally and could be ridden with a bit as per usual routine. It was concluded that using long laparoscopic instruments in combination with palpation, ultrasonography and/or radiography allowed removal of the foreign body creating minimal soft tissue trauma and allowing optimal conditions for a fast recovery.     

CRISPR-Cas Technology in Plant Science

CRISPR-Cas technology has raised considerable interest among plant scientists, both in basic science and in plant breeding. Presently, the generation of random mutations at a predetermined site of the genome is well mastered, just like the targeted insertion of transgenes, although both remain restricted to species or genotypes amenable for plant transformation. On the other hand, true genome editing, i.e. the deliberate replacement of one or several nucleotides of the genome in a predetermined fashion, is limited to some rather particular examples that generally concern genes allowing positive selection, for example tolerance to herbicides. Therefore, further technological developments are necessary to fully exploit the potential of genome editing in enlarging the gene pool beyond the natural variability available in a given species. In principle, the technology can be applied to any quality related, agronomical or ecological trait, under the condition of upstream knowledge on the genes to be targeted and the precise modifications necessary to improve alleles. Published proof of concepts concern a wide range of agronomical traits, the most frequent being disease resistance, herbicide tolerance and the biochemical composition of harvested products. The regulatory status of the plants obtained by CRISPR-Cas technology raises numerous questions, in particular with regard to the plants that carry in their genomes the punctual modifications caused by the presence of the Cas9 nuclease but not the nuclease itself. Without clarification by the competent authorities, CRISPR-Cas technology would continue to be a powerful tool in functional genomics, but its potential in plant breeding would remain untapped.     

Associations of fish with various types of littoral habitats in reservoirs

Fish associations with different types of littoral habitats were studied in four canyon‐shaped reservoirs in the Czech Republic in years 2010 and 2011 by gillnets. Two to three habitats per reservoir–beaches (former meadows), stump fields (former forest) and rubble slopes–were defined and sampled along the longitudinal axis of reservoirs. Effects of reservoir, habitat and locality (position along longitudinal axis) on fish biomass, abundance and species structure were tested for juvenile and adult fish separately. Hierarchical analysis of variance revealed that habitats differed significantly in fish biomass and abundance. Redundancy analysis showed that analysed environmental variables had significant influence on fish community structure. Most variability in community structure was explained by reservoir and then by combination of habitat and slope steepness. Locality position had the smallest influence on community structure. For both adult and juvenile fish total abundance and biomass, the most inhabited habitat was beaches; rubble slopes were the least inhabited. Habitat associations differed among species. Among adults, bream Abramis brama, white bream Blicca bjoerkna and roach Rutilus rutilus were associated with beaches and stump fields, whereas perch Perca fluviatilis, ruffe Gymnocephalus cernuus, asp Aspius aspius and pike Esox lucius were associated with rubble slopes. Bream, white bream, bleak Alburnus alburnus, roach, ruffe and pikeperch Sander lucioperca were associated with beaches among juveniles, whereas the only juvenile associated with rubble slopes was perch. We showed that most common species are associated with distinct habitats and also that utilisation of various littoral habitats differs in general.     

Evaluation of the Effects of Different Stunning Methods on the Stress Responses and Meat Quality of the Amazon hybrid surubim,Pseudoplatystoma fasciatum female × Leiarius marmoratus male

Different stunning methods (carbon dioxide [CO₂] and hypothermia) used in industrial fish processing were compared with asphyxia in air, which is used in traditional fishing, to evaluate the effects of these methods on the stress responses and the meat quality of the Amazon hybrid surubim, Pseudoplatystoma fasciatum female × Leiarius marmoratus male. After the application, blood and behavioral indicators were evaluated. Following death by gill cutting, the fish were gutted, and analyses of muscle pH, rigor mortis, the exudation of the meat, and coloration were performed. Significantly higher levels of cortisol and glucose were exhibited by the fish subjected to asphyxia than by the fish stunned by either CO₂ or hypothermia. The fish subjected to asphyxia displayed decreasing muscle pH during the first 2 h after death and showed higher rates of rigor mortis after 3 h than the fish that were stunned by the other two methods. The asphyxia is a practice that exposes fish to suffering by causing an increase in stress responses, which affects meat quality. The immersion of fish in water and ice (hypothermia) for 5 min was more effective stunning method than the use of CO₂, resulting in higher loss of sensibility and greater welfare.     

Population‐level effects of egg predation on a native planktivore in a large freshwater lake

Using a 37‐year recruitment time series, we uncovered a field pattern revealing a strong, inverse relationship between bloater Coregonus hoyi recruitment success and slimy sculpin Cottus cognatus biomass in Lake Michigan (United States), one of the largest freshwater lakes of the world. Given that slimy sculpins (and deepwater sculpin Myoxocephalus thompsonii) are known egg predators that spatiotemporally overlap with incubating bloater eggs, we used recently published data on sculpin diets and daily ration to model annual bloater egg consumption by sculpins for the 1973–2010 year‐classes. Although several strong year‐classes were produced in the late 1980s when the proportion of eggs consumed by slimy sculpins was extremely low (i.e., <0.001) and several weak year‐classes were produced when the proportion of bloater eggs consumed was at its highest (i.e., >0.10–1.0), egg predation failed to explain why recruitment was weak for the 1995–2005 year‐classes when the proportion consumed was also low (i.e., <0.02). We concluded that egg predation by slimy and deepwater sculpins could have limited bloater recruitment in some years, but that some undetermined factor was more important in many other years. Given that slimy sculpin densities are influenced by piscivorous lake trout Salvelinus namaycush, the restoration of which in Lake Michigan has lagged behind those in lakes Superior and Huron, our study highlights the importance of an ecosystem perspective when considering population dynamics of fishes.     

Transient bilateral blindness associated with presumptive idiopathic pachymeningitis in a 22-year-old Irish Sport Horse

A 22-year-old Irish Sport Horse presented following a period of bilateral blindness with subsequent spontaneous resolution. Brain magnetic resonance imaging (MRI) demonstrated features consistent with pachymeningitis. Cerebrospinal fluid (CSF) analysis revealed increased numbers of basophils, suggestive of an immunologic or neoplastic aetiology. It was suspected that the enlarged meninges led to compression of the optic nerves in the optic canals, causing bilateral blindness. Initial spontaneous remission, as seen in this case, has been reported in human patients with this condition. Pachymeningitis should be considered as a possible cause of cranial nerve deficits, including bilateral and unilateral blindness, in horses.     

Successive grafting confers juvenility traits to adult Spanish red cedar (Cedrela odorata Linnaeus): a tool for the rescue of selected materials

New Forests - Spanish red cedar, Cedrela odorata L. (Meliaceae), is a valuable timber tree in tropical American forests. Existing demand for elite individuals endangers the conservation of...     

Enhanced muscle regeneration in freshwater prawn Macrobrachium rosenbergii achieved through in vivo silencing of the myostatin gene

Myostatin (MSTN) is an interesting negative growth‐regulating gene that has been well characterized in vertebrates but scantly described in invertebrates. The current study focuses on the downregulation of the MrMSTN gene and subsequently records any histological changes for giant freshwater prawn, Macrobrachium rosenbergii (Mr). In addition, the study also deals with the MrMSTN gene's influence on other growth‐related genes, which include myosin heavy chain, dystrophin‐dystroglycoprotein complex, tropomyosin, farnesoic acid o‐methyl transferase, arginine kinase, cyclophilin, and acyl CoA desaturase. The preliminary histological analysis following MrMSTN silencing favors muscle regeneration, which supports its functional role as a negative growth regulator and its significant effect on the expression of other growth‐related genes. Overall, our results show that the MrMSTN gene could therefore be a potential target for gene manipulation aimed at enhancing the growth and muscle development of M. rosenbergii, which could be beneficial in increasing the total mass production in the postlarva phase at the hatchery level.