Effect of methanol concentration and thaw rate on the viability and fertility of cryopreserved Arctic char,Salvelinus alpinus (L.), spermatozoa

In two trials, Arctic char (Salvelinus alpinus) semen was frozen in 0.5 mL straws using extenders consisting of 0.3 M glucose and 10%, 12.5% or 15% methanol. Cryopreserved semen was thawed by immersing straws in 25 °C water for 17 s (11.6 °C s^?1) or in 5 °C water for 60 s (3.3 °C s^?1). The viability of the frozen–thawed semen was measured by determining post‐thaw motility and sperm membrane integrity. Two fertility trials were also conducted. There was no effect of trial or thaw rate on post‐thaw sperm viability or fertility. Use of 15% methanol in the extender resulted in the highest overall percentage of sperm motility and fertility. Use of 12.5% methanol as a cryoprotectant resulted in a higher per cent post‐thaw motility and a lower percentage of dead cells than did 10% methanol. Thus, levels of methanol higher than the commonly used 10% are beneficial for cryopreserving Arctic char sperm.     

Morphological characterization of Arctic char, Salvelinus alpinus, eggs subjected to rapid post-ovulatory aging at 7 °C

Egg quality in Arctic char, Salvelinus alpinus, kept indoors at 7 °C during spawning season was morphologically classified. Four egg categories based on lipid droplet distributions and egg diameter were characterized. Eggs with homogenous lipid vesicle distributions and a uniform size were classified as Good. Eggs with some yolk lipid droplets coalesced toward one pole but were homogeneous in size were classified as Fair. Eggs with lipid vesicles that were usually coalesced at one or two poles with were classified as Poor. The fourth egg category was Heterogeneous, in which lipid vesicle distribution and egg size were inhomogeneous. This distribution pattern of the lipid vesicle had a strong relationship with the percentage of fertilized and eyed eggs. Percentages of fertilized and eyed eggs in Good and Fair eggs were 85.5 and 83.4; 30.2 and 28.2, respectively. With Poor and Heterogeneous eggs, the percentages of fertilized and eyed eggs were zero. Egg diameter and absolute weight was increased in Poor eggs than in other egg categories. Relative weight increase during hardening after 30, 45 and 60 min were higher in Good and Fair eggs than in Poor and Heterogeneous eggs. Ovarian fluid collected from egg batches with low rates of fertilized and eyed eggs (Heterogeneous and Poor) had a lower pH and higher protein and aspartate amino-transferase enzyme than ovarian fluid from eggs batches classified as Good or Fair, while the ovarian fluid osmolality did not significantly differ. ATP contents of Poor and Heterogeneous eggs were lower than for Good and Fair eggs. In Heterogeneous eggs, both ATP and acid phosphatase contents were very variable.     

Compensatory growth,plasma hormones and metabolites in juvenile Siberian sturgeon (Acipenser baerii,Brandt 1869) subjected to fasting and re‐feeding

A 7‐week study was conducted to investigate the effect of different fasting and re‐feeding regimes on compensatory growth and some physiological parameters of juvenile Siberian sturgeon (Acipenser baerii). Fish (46.5 ± 0.5 g) were fed on a diet (containing 450 g/kg crude protein and 20 MJ/kg digestible energy) according to four feeding regimes in triplicate including: control group (C, fed everyday), W1 (2 weeks of feeding followed by 1 week of fasting and 4 weeks of re‐feeding), W2 (1 week of feeding followed by 2 weeks of fasting and 4 weeks of re‐feeding) and W3 (3 weeks of fasting followed by 4 weeks of re‐feeding). The fasted groups including W1 (119.6 ± 2.1 g), W2 (118.0 ± 1.7 g) and W3 (108.5 ± 4.8) significantly lost their weights during fasting phase and did not attain the final weight of the C (137.3 ± 1.7 g) after re‐feeding phase. The re‐feeding phase increased the specific growth rate in the fasted groups compared to the C (p < .05). After the fasting phase, concentrations of T₃, T₄, glucose, total protein and triglyceride in plasma of fasted groups were decreased, but levels of total cholesterol, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase increased compared to the C. After re‐feeding phase, except for glucose level, all mentioned metabolites were restored in the plasma of W1 group, but total protein level and aspartate aminotransferase concentrations in plasma were not restored in W2 and W3 groups. Overall, our finding demonstrated 4 weeks of re‐feeding was too short to induce full compensatory growth in A. baerii juveniles.     

Ultra-structural changes in the integument induced by the use of three of six forms of allylisothiocyanate tested against Plutella xylostella and Pieris rapae larvae

The insecticidal activity of four forms of Hong Jing (HJ) allylisothiocyanate (AITC), AITC + cypermethrin (HJ_A, HJ_B, and HJ_C) with ratio of (1:1, 4:1, and 2:1), pure AITC (HJ_D), and two forms of Hong Du (HD) AITC, AITC + chlorpyrifos (HD_A and HD_B) with ratio of (2:1 and 2:1), respectively, were studied on the major cruciferous insect larvae Plutella xylostella (L.) and Pieris rapae (L.) by combining both spraying and dipping methods. The P. rapae was more susceptible than P. xylostella larvae. The LC₅₀ values 72 h after treatment of AITC forms (HJ_B, HJ_A, HJ_C, HJ_D, HD_B, and HD_A) on the P. rapae were; 0.07, 0.08, 0.16, 0.83, 0.26, 1.08 gL⁻¹, and 0.69, 0.26, 5.45, 0.93, 3.01, 5.98 gL⁻¹ on the P. xylostella, respectively. The toxicity of some of the AITC forms was very close to or better than that of the commercial contact insecticides such as chlorpyrifos (LC₅₀ = 0.03 and 0.04 gL⁻¹ on P. rapae and P. xylostella, respectively), and cypermethrin (0.65 and 0.78 gL⁻¹, respectively, against P. rapae and P. xylostella). The ultrastructural studies on the integument of the third larval instar of P. xylostella treated by sub-lethal concentration (LC₂₀) of HJ_B, HJ_D, and HD_B were carried out by using transmission electron microscope. The more pronounced alterations in the hypodermis and mitochondria cells. They exhibited changes in all treated samples. The hypodermis was almost completely destroyed, and the mitochondria exhibited morphological alterations, represented by enlargement, matrix rarefaction and vacuolization of the mitochondria matrix, quantity of cristae reduced, and density electron matrix lessened. These AITC forms have potential as contact insecticides, and the ultra structural observations confirm the insecticidal efficiency of different AITC forms on P. rapae and P. xylostella.     

Yersinia ruckeri,the causative agent of enteric redmouth disease in fish

Enteric redmouth disease (ERM) is a serious septicemic bacterial disease of salmonid fish species. It is caused by Yersinia ruckeri, a Gram-negative rod-shaped enterobacterium. It has a wide host range, broad geographical distribution, and causes significant economic losses in the fish aquaculture industry. The disease gets its name from the subcutaneous hemorrhages, it can cause at the corners of the mouth and in gums and tongue. Other clinical signs include exophthalmia, darkening of the skin, splenomegaly and inflammation of the lower intestine with accumulation of thick yellow fluid. The bacterium enters the fish via the secondary gill lamellae and from there it spreads to the blood and internal organs. Y. ruckeri can be detected by conventional biochemical, serological and molecular methods. Its genome is 3.7 Mb with 3406–3530 coding sequences. Several important virulence factors of Y. ruckeri have been discovered, including haemolyin YhlA and metalloprotease Yrp1. Both non-specific and specific immune responses of fish during the course of Y. ruckeri infection have been well characterized. Several methods of vaccination have been developed for controlling both biotype 1 and biotype 2 Y. ruckeri strains in fish. This review summarizes the current state of knowledge regarding enteric redmouth disease and Y. ruckeri: diagnosis, genome, virulence factors, interaction with the host immune responses, and the development of vaccines against this pathogen.     

Antioxidant response element activator,BTZO-1, improves the developmental competence of bovine oocytes

Increased reactive oxygen species (ROS) generation may disrupt the oocytes function and their competence. In this study, we introduced BTZO-1, a new supplement that can regulate the oxidative stress. Addition of BTZO-1 during IVM of bovine oocytes improved their developmental competence in the term of improvement of blastocyst rates. In addition, the quality of the produced embryos was improved by decreasing the apoptosis level by showing a decreased number of TUNNEL positive cells.     

Silicon-nanoparticle Mediated Changes in Seed Germination and Vigor Index of Marigold (Calendula Officinalis L.) Compared to Silicate Under PEG-induced Drought Stress

Gesunde Pflanzen - The current study explores the potential impact of seed priming with silicon nanoparticles (SiNPs, 0, 100, 200, 500?mg/L) and silicate (Si, 0, 1, 1.5, 2?mg/L) under...     

Synergistic Effect of Biosynthesized Silver Nanoparticles and Natural Phenolic Compounds against Drug-Resistant Fish Pathogens and Their Cytotoxicity: An In Vitro Study

Fish pathogens causing disease outbreaks represent a major threat to aquaculture industry and food security. The aim of the presented study is to develop safe and effective bioactive agents against two bacterial isolates: Aeromonas hydrophila and Pseudomonas fluorescens. We employed a broth microdilution method to investigate the antibacterial effect of biosynthesized silver nanoparticles (AgNPs); rutin, a natural flavonoid extracted from Ruta graveneoles; and heliomycin, a secondary metabolite produced by marine actinomycetes AB5, as monotherapeutic agents. Moreover, AgNPs in combination with rutin (AgNP + R) and heliomycin (AgNPs + H) were examined for their synergistic effect. The cytotoxic effect of individual bioactive compounds and in combination with AgNPs was investigated on epithelioma papulosum cyprini (EPC) fish cell lines. Individual treatment of AgNPs, rutin, and heliomycin exhibited a dose-dependent antimicrobial activity against A. hydrophila and P. fluorescens. Rutin minimum inhibitory concentration (MIC) showed the lowest cytotoxicity when tested on EPC cell lines, while heliomycin MIC was highly cytotoxic. Combined subtherapeutic doses of AgNPs + R and AgNPs + H displayed additive and synergistic effects against A. hydrophila and P. fluorescens, respectively, with improved results and relative safety profile. The study findings demonstrate that a combination of AgNPs and natural bioactive compounds may represent novel therapeutics fighting fish pathogens potentially affecting the fish farming industry.     

Grapevine trunk diseases: complex and still poorly understood

This review presents an overview of eutypa dieback, esca and botryosphaeria dieback, the predominant grapevine trunk diseases worldwide. It covers their symptomatologies in the trunk, leaves and berries; the characteristics of the different fungal species associated with them; and host–pathogen interactions. Here, the host–pathogen relationship is defined at the cytological, physiological and molecular levels. Currently available experimental tools for studying these diseases, both in vitro and in the field, are discussed. Finally, a progress report on their control, which, since the ban of sodium arsenite, comprises chemical, biological and/or sanitation methods, is presented.