Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.     

Wheat arabinoxylans: Exploiting variation in amount and composition to develop enhanced varieties

Arabinoxylans (AX) are the major polymers of wheat grain cell walls. The content and the structure of AX polymers show large differences between tissues and between wheat cultivars that affect the end-use properties and nutritional quality of the grain. The development of new wheat cultivars with enhanced quality, therefore, requires methods to exploit this variation and it is essential to understand and modulate the mechanisms controlling the key events of cell-wall polymer synthesis.This paper summarises recent knowledge on the structure and physicochemical properties of AX including variation between cultivars and tissues, methods for analysis and screening, biosynthetic mechanisms and approaches to identifying key genes. This knowledge is essential to understand AX properties and defined possible targets for plant breeding.     

Feeding Dietary Mannan Oligosaccharides to Juvenile Nile Tilapia,Oreochromis niloticus,Has No Effect on Hematological Parameters and Showed Decreased Feed Consumption

Impaired immune system by environmental stressors can lead fishes to be more susceptible to diseases that limit the economic development of aquaculture systems. This study was set out to determine the effect of six levels of mannan oligosaccharides (MOS; ActiveMOS^®; Biorigin, Lençois Paulista, São Paulo , Brazil) on the performance index and hematology of Nile tilapia, Oreochromis niloticus juveniles. Fish (13.62 g) were randomly distributed into 18 plastic aquaria (300 L; 20 fishes per aquarium) and fed during 45 d with a commercial diet supplemented with 0, 0.2, 0.4, 0.6, 0.8, and 1% dietary MOS, in a totally randomized design trial (n = 3); biometrical and hematological data were collected and analyzed. There were no significant differences in hematological parameters between fish fed control and MOS supplementation diets, and daily feed consumption (FC) decreased (P < 0.05) with increasing levels of dietary MOS. Dietary MOS did not increase leukocyte count and presented negative effects on FC of Nile tilapia. At 0.4% MOS supplementation, the individual weight gain was higher in absolute values but not different (P > 0.05) compared to control diet.     

Heat-treated bean (Phaseolus vulgaris) residue meal as an alternative protein source in pelleted diets for Nile tilapia fingerlings: growth,body composition,and physical characteristics of diets

Tropical Animal Health and Production - The study aimed to evaluate heat-treated bean residue meal (Phaseolus vulgaris)—BRM—as an alternative protein source in diets for Nile tilapia...     

Influence of the anaesthetic quinaldine on some tilapias

Three species of tilapia, Sarotherodon melanotheron and Sarotherodon guineensis from brackish water and Oreochromis (Sarotherodon) niloticus from fresh water, were exposed to different concentrations of the anaesthetic quinaldine to determine the safe level for handling and transportation of these species. It was observed that the time taken to lose balance increased with a decrease in the concentration of the anaesthetic. This was probably due to the very low concentration of the hydrogen ions in the progressively diluted test media. Dosages of quinaldine for handling fish for experimental work and for transportation are given with the proviso that the anaesthetization is carried out under conditions of salinity and temperature which are suitable for acclimation.     

Expression of the alpha6 chain of type IV collagen in glomerular basement membranes of healthy adult dogs

OBJECTIVE: To evaluate expression of the alpha6 chain of type IV collagen in the glomerular basement membranes (GBM) of healthy dogs. SAMPLE POPULATION: Kidney specimens from 12 healthy dogs. For comparison, kidney specimens from 8 human subjects between 25 and 83 years old also were evaluated. PROCEDURE: Sections were immunolabeled with a monospecific antibody that cross-reacts with human and canine alpha6(IV) chains and examined by means of fluorescence microscopy. RESULTS: Immunolabeling of the alpha6(IV) chain was not observed in GBM of 6 dogs < or = 30 months old but was observed in GBM of the remaining 6 dogs, all of which were > or = 45 months old. Expression of the alpha6(IV) chain was not observed in GBM of the human subjects, regardless of the age of the subject. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that the alpha6(IV) chain is expressed in GBM of healthy dogs, but the expression is age-dependent. Composition and structural organization of type IV collagen in the GBM of healthy adult dogs is different from that described for other species.     

New form of X-linked dominant hereditary nephritis in dogs

OBJECTIVE: To determine features of a new form of hereditary nephritis (HN) in dogs. ANIMALS: Parents and 16 first-generation offspring (8 males, 8 females). PROCEDURE: Adolescent dogs that developed renal failure were euthanatized and necropsied. Unaffected dogs were monitored until they were at least 2 years old. Studies included light and electron microscopy of kidneys obtained from affected and unaffected dogs and immunolabeling for collagen-IV chains in renal and epidermal basement membranes (BM). The nucleotide sequence of a portion of exon 35 of the COL4A5 gene was determined in genomic DNA isolated from affected and unaffected males. RESULTS: 7 of 8 male and 2 of 8 female offspring had proteinuria and juvenile-onset chronic renal failure, which progressed more rapidly in the males. Labeling for alpha3-alpha6(IV) chains was completely absent in renal BM of affected males and segmentally absent in affected females. Expression of alpha1-alpha2(IV) chains in glomerular BM (GBM) of affected dogs was increased. Labeling for alpha5-alpha6(IV) chains in epidermal BM was absent in affected males and segmental in affected females. Ultrastructural changes characteristic of HN were observed in GBM of affected dogs. The sequence of exon 35 of COL4A5 was normal in affected dogs. CONCLUSIONS: This renal disease is an example of X-linked dominant HN, with typical abnormalities of GBM ultrastructure and alpha(IV) chain expression. CLINICAL RELEVANCE AND IMPLICATIONS FOR HUMAN MEDICINE: Dogs with this naturally acquired progressive renal disease can be used to investigate the pathogenesis and treatment of similar disorders in human beings and dogs.     

Growth and haematology of pacu, Piaractus mesopotamicus, fed diets with varying protein to energy ratio

Haematopoiesis and blood cells' functions can be influenced by dietary concentration of nutrients. This paper studied the effects of dietary protein:energy ratio on the growth and haematology of pacu, Piaractus mesopotamicus . Fingerling pacu (15.5±0.4 g) were fed twice a day for 10 weeks until apparent saciety with diets containing 220, 260, 300, 340 or 380 g kg⁻¹ crude protein (CP) and 10.88, 11.72, 12.55, 13.39, 14.22 MJ kg⁻¹ digestible energy (DE) in a totally randomized experimental design, 5 × 5 factorial scheme ( n =3). Weight gain and specific growth rate were affected ( P <0.05) by protein level only. Protein efficiency ratio decreased ( P <0.05) with increasing dietary protein at all levels of dietary energy. Daily feed intake decreased ( P <0.05) with increasing dietary energy. Mean corpuscular haemoglobin concentration was affected ( P <0.05) by DE and interaction between dietary CP and DE. Total plasma protein increased ( P <0.05) with dietary protein and energy levels. Plasma glucose decreased ( P <0.05) with increasing dietary protein. The CP requirement and optimum protein:energy ratio for weight gain of pacu fingerlings, determined using broken-line model, were 271 g kg⁻¹ and 22.18 g CP MJ⁻¹ DE respectively. All dietary CP and DE levels studied did not pose damages to fish health.     

MiFish metabarcoding: a high-throughput approach for simultaneous detection of multiple fish species from environmental DNA and other samples

Fisheries Science - We reviewed the current methodology and practices of the DNA metabarcoding approach using a universal PCR primer pair MiFish, which co-amplifies a short fragment of fish DNA...     

Protein‐sparing effect by dietary lipid increase in juveniles of the hybrid fish tambatinga (♀Colossoma macropomum × ♂Piaractus brachypomus)

This research assessed four levels of crude protein—200, 250, 300 and 350 g/kg—associated with two crude lipid concentrations—110 and 140 g/kg—in diets for juveniles of tambatinga (♀Colossoma macropomum × ♂Piaractus brachypomus) over 63 days. The fish (15.2 ± 0.2 g) were distributed in 24–160 L tanks (11 fish/tank) in a 4 × 2 completely randomized factorial design (n = 3). Increasing the lipid content in the diets reduced (p < 0.05) the protein requirements for weight gain from 326 g/kg (diets with 110 g/kg LIP) to 255 g/kg (diets with 140 g/kg). Protein retention in the fish increased (p < 0.05) when they were fed up to 293 g/kg CP and 140 g/kg LIP; in the diets with 110 g/kg LIP, protein retention decreased linearly (p < 0.05) as the protein content in the diets increased. Feed efficiency increased (p < 0.05) when the fish received up to 308 g/kg CP regardless of lipid concentration (p > 0.05). In conclusion, tambatinga juveniles at 15–120 g have a minimum requirement of 255 g/kg CP and 140 g/kg CL and a protein:energy ratio of 17.4 g CP kJ/digestible energy (DE).