Effects of calpain-2 and autophagy-related protein 5 on hepatocyte apoptosis induced by endoplasmic reticulum stress

AIMTo investigate the effects of calpain-2 and autophagy-related protein 5 (Atg5) on apoptosis of BRL-3A rat normal liver cells during endoplasmic reticulum stress (ERS) induced by dithiothreitol (DTT). METH?ODS: BRL-3A cells were treated with DTT at 2.0 mmol/L for 0, 6, 12 and 24 h to induce ERS. Real-time cell analysis (RTCA) was used to measure the effect of DTT on BRL-3A cell proliferation. Apoptosis and cell cycle distribution were analyzed by flow cytometry. The mRNA expression of calpain-2 and Atg5 was detected by real-time PCR. The protein levels of calpain-2, Atg5, Atg7, Atg12 and microtubule-associated protein 1 light chain 3 (LC3) were determined by Western blot. The interaction between calpain-2 and Atg5 was investigated by co-immunoprecipitation (Co-IP). RESULTSThe proliferation of BRL-3A cells treated with DTT was significantly inhibited. The apoptosis of BRL-3A cells was significantly increased after DTT treatment for 6, 12 and 24 h as compared with 0 h group (P<0.05). The cell cycle was arrested in G₁ phase after DTT treatment (P<0.05). After DTT treatment for 6, 12 and 24 h, the mRNA expression of calpain-2 and Atg5 in the BRL-3A cells was significantly increased as compared with 0 h group (P<0.05). The protein levels of calpain-2, Atg12 and Atg7 in the cells treated with DTT for 6, 12 and 24 h were significantly higher than those in 0 h group, and the ratio of LC3-II/LC3-I was also significantly higher than that in 0 h group, while Atg5 expression was significantly lower than that in 0 h group (P<0.05). The results of Co-IP found that the anti-calpain-2 antibody precipitated Atg5 protein from the cell lysates, and the anti-Atg5 antibody also precipitated calpain-2 from the cell lysates, which confirmed the interaction between calpain-2 and Atg5. CONCLUSION Calpain-2 may participate in ERS-induced hepatocyte apoptosis by interacting with Atg5.     

Effects of different long-term cropping systems on phosphorus adsorption and desorption characteristics in red soils

Journal of Soils and Sediments - Phosphorus (P) fertilizer has been applied in regions with red soils to ensure high crop yield. However, the supply of bioavailable P for crop plants is...     

Influence of in-house produced biochars on cracks and retained water during drying-wetting cycles: comparison between conventional plant,animal, and nano-biochars

Purpose

Biochars produced from different feedstocks (such as wood, pig manure) possess varying physical and chemical properties, which have influence on crack and evaporation rate of biochar-amended soil (BAS). Furthermore, influence of compaction state and drying-wetting cycles on evaporation rate and cracking of BAS has not been investigated comprehensively. The objective of this study was to investigate the effects of biochar types, compaction state of BAS, and drying-wetting cycles on crack propagation and retained water (or evaporation rate).

Material and methods

An animal and plant feedstock-based biochars were produced in-house from pig manure (PM) and wood (W), respectively. In addition, nano structured chalk and wheat biochar (CWB) were also produced. Soil amended with individual biochars was compacted in petri-glass discs at two densities. Disc specimens were subjected to multiple drying-wetting cycles, and evaporation rate of specimens and crack area were monitored throughout the experimental period (70 days). Images were captured after every 24 h and processed using image processing technique to obtain the crack intensity factor (CIF).

Results and discussion

The results show that plant-based W BAS showed the high water retention, i.e., low evaporation rate and low CIF. Furthermore, the crack potential of CW BAS was seen to be higher. In dense compacted soil, maximum CIF% can be reduced from 3.9 to 0.4% for W BAS, from 3.9 to 1.7% for PM BAS, and from 3.9 to 1.6% for CW BAS.

Conclusion

WB was able to resist cracking more efficiently than other types of biochar. Evaporation was found to be minimal for plant-based W BAS at 10% biochar percentage. Higher biochar content in soil was seen to increase the water retention of BAS significantly. Dense state of BAS at high biochar content (i.e., 10%) was effective in reducing evaporation rate and crack progression.

     

Strangulation of the duodenum just oral to its caudal flexura caused by a volvulus

An 8-year-old Haflinger mare with a 10-day-old foal at foot was referred with mild abdominal pain. On the basis of clinical examination, blood and peritoneal fluid analysis, the cause of pain was suspected septic peritonitis. The horse was initially managed medically, with the horse placed in box confinement under close monitoring. No permission was given for an exploratory laparotomy, and it was decided to perform a diagnostic laparoscopy in the standing horse. The laparoscopy revealed a 360-degree anticlockwise partial duodenal volvulus of the caudal descending duodenum, which was manually reduced (hand-assisted laparoscopy). After the release, the mesentery of the duodenum showed an ischaemic band (yellowish white and dark red with a hyperaemic side) and the duodenum had a distinct ischaemic ring (orally and aborally) distinguishing the incarcerated part from the normal duodenum. Ten minutes after the release, the colour remained the same. In conjunction with the owner, it was decided to euthanise the pony. Pathology confirmed the presence of a strangulation ring and the ischaemic condition of the involved duodenum.     

Thresholds,sensitive stages and genetic variability of finger millet to high temperature stress

Finger millet [Eleusine coracana (L.) Gaertn.] is an important coarse cereal crop grown in the arid and semi‐arid regions and often experiences high temperature (HT) stress. The objectives of this research were (i) to quantify effects of season‐long HT stress on physiological and yield traits, (ii) to identify the developmental stages most sensitive to HT stress and (iii) to quantify the genetic variability for HT stress tolerance in finger millet. Research was conducted in controlled environment conditions. HT stress decreased the chlorophyll index, photosystem II activity, grain yield and harvest index. Maximum decrease in number of seeds per panicle and grain yield per plant was observed when stress was imposed during booting, panicle emergence or flowering stages. Maximum genotypic variation was explained by panicle width and number of seeds per panicle at optimum temperature (OT) and grain yield per plant at HT and number of seeds at HT. Based on the stress response and grain yield, tolerant or susceptible genotypes were identified. Finger millet is sensitive to HT stress during reproductive stages, and there was genotypic variability among the finger millet genotypes for number of seeds per panicle and grain yield under HT, which can be exploited to enhance stress tolerance.     

Temperature modulates liver lipid accumulation in Atlantic salmon (Salmo salar L.) fed low dietary levels of long‐chain n‐3 fatty acids

Atlantic salmon (Salmo salar) were fed five graded levels of eicosapentaenoic acid (EPA, 20:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3), from 1.4 to 5.2% of total fatty acids (FA, 5–17 mg kg^?1 feed), and grew from ~160 g to ~3000 g, with the period from 1450 g onwards conducted both at 6 °C and at 12 °C. All fish appeared healthy, and there were no diet‐related differences in haematological or plasma parameters, as well as intestinal histological or gut microbiota analysis. Fish reared at 6 °C had higher accumulation of storage lipids in the liver compared to fish reared at 12 °C. Liver lipids also increased with decreasing dietary EPA + DHA at 6 °C, while there was no such relationship at 12 °C. Gene expression of SREBP1 and 2, LXR, FAS and CPT1 could not explain the differences in liver lipid accumulation. In liver polar lipids, DHA was found to be reduced when dietary EPA + DHA was <2.7% of FAs, while the level of EPA in the membranes was not affected. In conclusion, reducing dietary EPA + DHA from 5.2 to 1.4% of total FAs had a minor impact on fish health. Temperature was the factor that most affected the liver lipid accumulation, but there was also an interaction with dietary components.     

Effect of substitution of dietary fish meal by soybean meal on different sizes of gibel carp (Carassius auratus gibelio): digestive enzyme gene expressions and activities,and intestinal and hepatic histology

A 7‐week growth trial was conducted to evaluate the effects of dietary soybean meal (SBM) on digestive enzyme activity of intestinal mucosa, mRNA levels of digestive enzymes in hepatopancreas, and the mid‐intestinal and hepatopancreas histology of gibel carp CAS III (Carassius auratus gibelio). Four different growth phases of gibel carp (initial body weight: fry, 0.8 g; juvenile, 5.0 g; 1‐year‐old, 62.7 g; and broodstock, 135.6 g) were tested. Seven isonitrogenous and iso‐energetic diets were formulated to contain different SBM replacement levels (0%, 20%, 40%, 60%, 80% and 100% of dietary fish meal protein), and another diet (SBMAA) contained all SBM protein and supplied crystalline amino acids. The results showed that the activities of mid‐intestine trypsin, α‐amylase and gamma glutamyl transpeptidase reduced with increased dietary SBM, while the chymotrypsin activity increased first and then decreased. The ultrastructures of intestinal epithelial cells and hepatopancreas cells in fry and broodstock fish were distinctly affected by 200 g kg^‐1 dietary SBM. Supplementation of dietary amino acid to the highest replacement groups was not sufficient to improve digestive and absorptive capacities and growth performance. Gibel carp may be adapted to dietary SBM through increase in gene expression of hepatopancreas digestive enzymes and has potential to utilize proceeded SBM as feedstuffs.     

Dietary α‐linolenic acid affects lipid metabolism and tissue fatty acid profile and induces apoptosis in intraperitoneal adipose tissue of juvenile grass carp (Ctenopharyngodon idella)

A 56‐day feeding trial was conducted to elucidate the effects and mechanism action of dietary α‐linolenic acid (ALA, 18:3n‐3) on lipid accumulation and fatty acid profile of muscle, hepatopancreas and intraperitoneal fat (IPF) in juvenile grass carp using three isonitrogenous and isoenergetic semi‐purified diets containing 0.0% (control group), 1.0% and 2.0% ALA, respectively. The lowest intraperitoneal fat (IPF) ratio was found in 2.0% group. In the muscle, hepatopancreas and IPF, docosahexaenoic acid (DHA, 22:6n‐3) and eicosapentaenoic acid (EPA, 20:5n‐3) contents increased with the increase in dietary ALA. In the IPF, caspase 3, caspase 8 and caspase 9 showed the highest activities in 2.0% group, while the value of Bcl‐2/Bax (B‐cell leukaemia 2/Bcl‐2‐associated X protein) reached the lowest. Meanwhile, swelling of the IPF mitochondria was observed in 2.0% group. The gene expressions of fatty acid desaturase (FAD) and fatty acid elongase (ELO) in the hepatopancreas and muscle showed significantly higher levels in the treatment groups, whereas an opposite trend was existed in the IPF. Fatty acid synthase (FAS), sterol regulatory element binding protein‐1c (SREBP‐1c) in the IPF and hepatopancreas reached the lowest in 2.0% group. Overall, dietary ALA could promote n‐3 highly unsaturated fatty acids (HUFAs) synthesis and suppress the accumulation of lipid by decreasing the expression of related genes and promoting the apoptosis in IPF.     

Natural bixin as a potential carotenoid for enhancing pigmentation and colour in goldfish (Carassius auratus)

Discovering natural carotenoids for colour enhancement and health benefits of fish is important to develop new feed formulations. We have purified natural bixin from achiote seeds and evaluated the effect of colour enhancing and pigmentation in goldfish. Varying levels of bixin‐based diets were prepared with 420 g kg^?1 of crude protein and 120 g kg^?1 of lipid content. Our results clearly showed that bixin (0.05, 0.10, 0.20 and 0.60 g kg^?1) based diets significantly (P < 0.05) enhanced the skin and fin colour at 30 and 60 days compared to diet without bixin. Interestingly, diet which contains 0.20 g kg^?1 bixin and commercial feed (with astaxanthin) had similar effect on carotenoid deposition in skin. Moreover, total carotenoid deposition in fin was higher than in skin of all bixin‐containing diets. However, 0.60 g kg^?1 bixin‐containing diet had lower specific growth rate (1.01 ± 0.01) and higher feed conversion ratio (2.05 ± 0.19) compared to the control group. The present results demonstrate that achiote bixin can be successfully used as an alternative natural carotenoid source against synthetic astaxanthin in fish feed. Our data indicate that 0.20 g kg^?1 is a suitable dietary level of bixin to ensure strong pigmentation, acceptable growth and feed utilization in goldfish.     

Effects of starvation,subsequent feeding and photoperiod on flesh quality in farmed cod (Gadus morhua)

The study was designed to investigate the effect of four cycles of 5 weeks starvation followed by 10‐week refeeding compared with daily feeding under either natural photoperiod or continuous light (LL) regime on body composition and flesh quality in Atlantic cod in sea cages, northern Norway. The fish were sampled for body composition and flesh quality parameters at the start of the trial, twice at the end of a 10‐week feeding period and twice at the end of a 5‐week starvation period. There was effect of both feeding and light regime on growth, the two starving groups losing weight during starvation and regaining weight during refeeding, and the group under LL being heavier. But, the mean overall growth did not vary between groups. Starvation/refeeding regime resulted in higher slaughter yield, but no overall effect was seen on hepatosomatic index, water content, water holding capacity (WHC), muscle pH, hardness or flesh colour compared with control groups. Continuous light increased gutted weight and slaughter yield, lowered WHC and depressed maturation compared with fish under natural light regime. Increased growth rate resulted in softer fillets and lower muscle pH.