Lipid characteristics associated with oxidative and glycolytic fibres in rabbit muscles

The purpose of this study was to specify the intramuscular lipid characteristics which are related to the metabolic type of muscles. Two glycolytic muscles (Longissimus lumborum and Psoas major), two oxidative ones (Soleus and Semimembranosus propriosus) and an intermediate one (Gastrocnemius laterale) were dissected from rabbit carcasses. The results showed that:

1. (a) The glycolytic muscles contain less total lipids, triglycerides and cholesterol than the oxidative ones.

2. (b) Phospholipid content, cardiolipin and PE proportions were lower and PI proportion was higher in the glycolytic muscles than in the oxidative ones.

3. (c) The phospholipids of the glycolytic muscles contain more 16:0 and 18:2 n−6 but less 18:0 and long chain polyunsaturated fatty acids (20:4 n−6, 22:5 n−6 and n−3) than those of the oxidative muscles.

     

Personalized assessment of oxidative cellular damages associated with diabetes using erythrocytes adhesion assay

Increased generation of reactive oxygen species (ROS) is recognized as a prominent feature of vascular dysfunction with diabetes. For self-monitoring of the risk of diabetic complications, we proposed a simple adhesion test of erythrocytes using positively charged surfaces and its adhesion property was found to correlate HbA_1c level in diabetic patients.     

Liposome-assisted activity of superoxide dismutase under oxidative stress

A biological membrane is the front line of defense for cells against various environmental stresses such as heat and reactive oxygen species (ROS) and is expected to play an important role in the antioxidant system with antioxidant enzymes, similarly to its chaperone-like function in cooperation with heat shock proteins. The oxidative stress response of superoxide dismutase (SOD), which is known to catalyze the dismutation of O(2)(-) to H(2)O(2), was investigated in the presence of artificial membranes, liposomes, in order to obtain fundamental information on the biological ROS scavenging system. SOD lost its activity in the presence of H(2)O(2) and was found to have two loops including one which contains an alpha-helix which presents the substrate O(2)(-) to the activity center of SOD (Cu(II)). From circular dichroism analysis of SOD in the presence of H(2)O(2), the contents of the alpha-helix in SOD were found to decrease in correspondence with the inactivation and conformational change of SOD, suggesting that the conformation of the alpha-helix loops affects SOD activity. In the presence of liposomes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), SOD was not inactivated in the presence of H(2)O(2) although the contents of its alpha-helix structure were decreased. The oxidized SOD was found to interact with the liposome surface under oxidative stress using dielectric dispersion analysis. Based on these results, a possible mechanism of SOD protection against ROS on liposomes was presented.     

Amino acid-decarboxylase activity in bacteria associated with Mediterranean hake spoilage

We examined the amino acid-decarboxylase activity of bacteria isolated throughout the ice storage of Mediterranean hake. Pseudomonas was the main microbial group in the fresh samples. Its number increased by up to 2 logarithmic units during the storage and 20% of the isolates showed the ability to produce putrescine. Shewanella putrefaciens was the most prolific organism and became the dominant microbial group on day 6 of storage. It also had the highest proportion of aminogenic isolates and the strongest decarboxylase potential as a tyramine- and cadaverine-producing microorganism. A competitive procedure in biogenic amine production seems to have occurred when trimethylamine oxide was available in the culture medium. The abundance of Enterobacteriaceae increased gradually throughout the storage but never reached high counts and their isolates produced small amounts of cadaverine only. Although the counts of micrococci and staphylococci were considerably high, only two isolates were ornithine-decarboxylase positive. Neither lactic acid bacteria nor enterococci were positive.     

Autoinducer-2-like activity associated with foods and its interaction with food additives

The autoinducer-2 (AI-2) molecule produced by bacteria as part of quorum sensing is considered to be a universal inducer signal in bacteria because it reportedly influences gene expression in a variety of both gram-negative and gram-positive bacteria. The objective of this study was to determine whether selected fresh produce and processed foods have AI-2-like activity and whether specific food additives can act as AI-2 mimics and result in AI-2-like activity. The luminescence-based response of the reporter strain Vibrio harveyi BB170 was used as the basis for determining AI-2 activity in the selected foods and food ingredients. Maximum AI-2 activity was seen on the frozen fish sample (203-fold, compared with the negative control) followed by tomato, cantaloupe, carrots, tofu, and milk samples. Interestingly, some samples were capable of inhibiting AI-2 activity. Turkey patties showed the highest inhibition (99.8% compared with the positive control) followed by chicken breast (97.5%), homemade cheeses (93.7%), beef steak (90.6%), and beef patties (84.4%). AI-2 activity was almost totally inhibited by sodium propionate, whereas sodium benzoate caused 93.3% inhibition, compared with 75% inhibition by sodium acetate. Sodium nitrate did not have any appreciable effect, even at 200 ppm. Understanding the relationships that exist between AI-2 activity on foods and the ecology of pathogens and food spoilage bacteria on foods could yield clues about factors controlling food spoilage and pathogen virulence.     

Effect of water activity on oxidative deterioration of freeze-dried beef

The effect of water activity on lipid oxidation in freeze-dried beef was studied. Analytical indices of the extent of oxidation (thiobarbituric acid (TBA) number and Ex 350Ee320 fluorescence ratio) showed that samples of water activity 0.270 underwent less oxidation during 84 days storage in oxygen at 50°C than samples of lower water activity. Samples stored under nitrogen, irrespective of water activity, did not show any oxidation.     

Carbon, hydrogen, and nitrogen isotope fractionation associated with oxidative transformation of substituted aromatic N-alkyl amines

We investigated the mechanisms and isotope effects associated with the N-dealkylation and N-atom oxidation of substituted N-methyl- and N,N-dimethylanilines to identify isotope fractionation trends for the assessment of oxidations of aromatic N-alkyl moieties by compound-specific isotope analysis (CSIA). In laboratory batch model systems, we determined the C, H, and N isotope enrichment factors for the oxidation by MnO(2) and horseradish peroxidase (HRP), derived apparent (13)C-, (2)H-, and (15)N-kinetic isotope effects (AKIEs), and characterized reaction products. The N-atom oxidation pathway leading to radical coupling products typically exhibited inverse (15)N-AKIEs (up to 0.991) and only minor (13)C- and (2)H-AKIEs. Oxidative N-dealkylation, in contrast, was subject to large normal (13)C- and (2)H-AKIEs (up to 1.019 and 3.1, respectively) and small (15)N-AKIEs. Subtle changes of the compound's electronic properties due to different types of aromatic and/or N-alkyl substituents resulted in changes of reaction mechanisms, rate-limiting step(s), and thus isotope fractionation trends. The complex sequence of electron and proton transfers during the oxidative transformation of substituted aromatic N-alkyl amines suggests highly compound- and mechanism-dependent isotope effects precluding extrapolations to other organic micropollutants reacting along the same degradation pathways.     

Cytoprotective effect of fruit extracts associated with antioxidant activity against ultraviolet rays

Antioxidant activity in the extracts of Redfield apple flesh, Pione grape berry skin, and Ishiji satsuma mandarin skin was evaluated by a superoxide dismutase (SOD) assay and hemolysis of red blood cell assay. Although SOD activity was higher in both the Redfield apple flesh and Pione grape berry skin, hemolysis of the red blood cells was delayed most in the Redfield apple flesh, followed by the Pione grape berry skin and Ishiji satsuma mandarin skin. The protective effects of extracts from these fruits against ultraviolet rays were also examined using human skin dermal fibroblasts. The Redfield flesh extract increased the percentage of cell viability against ultraviolet rays compared to the untreated control. The participation of polyphenolics in Redfield apples is discussed.     

Antifungal activity of Azotobacter nigricans against trichothecene-producing Fusarium species associated with cereals

Food Science and Biotechnology - Antifungal efficacy of Azotobacter nigricans on Fusarium infection, total seedlings mass, root and shoot length, and seed germination in maize, sorghum, and wheat...     

Mitochondrial protein gene expression and the oxidative phosphorylation pathway associated with feed efficiency and energy balance in dairy cattle

Feed efficiency and energy balance are important traits underpinning profitability and environmental sustainability in animal production. They are complex traits, and our understanding of their underlying biology is currently limited. One measure of feed efficiency is residual feed intake (RFI), which is the difference between actual and predicted intake. Variation in RFI among individuals is attributable to the metabolic efficiency of energy utilization. High RFI (H_RFI) animals require more energy per unit of weight gain or milk produced compared with low RFI (L_RFI) animals. Energy balance (EB) is a closely related trait calculated very similarly to RFI. Cellular energy metabolism in mitochondria involves mitochondrial protein (MiP) encoded by both nuclear (NuMiP) and mitochondrial (MtMiP) genomes. We hypothesized that MiP genes are differentially expressed (DE) between H_RFI and L_RFI animal groups and similarly between negative and positive EB groups. Our study aimed to characterize MiP gene expression in white blood cells of H_RFI and L_RFI cows using RNA sequencing to identify genes and biological pathways associated with feed efficiency in dairy cattle. We used the top and bottom 14 cows ranked for RFI and EB out of 109 animals as H_RFI and L_RFI, and positive and negative EB groups, respectively. The gene expression counts across all nuclear and mitochondrial genes for animals in each group were used for differential gene expression analyses, weighted gene correlation network analysis, functional enrichment, and identification of hub genes. Out of 244 DE genes between RFI groups, 38 were MiP genes. The DE genes were enriched for the oxidative phosphorylation (OXPHOS) and ribosome pathways. The DE MiP genes were underexpressed in L_RFI (and negative EB) compared with the H_RFI (and positive EB) groups, suggestive of reduced mitochondrial activity in the L_RFI group. None of the MtMiP genes were among the DE MiP genes between the groups, which suggests a non-rate limiting role of MtMiP genes in feed efficiency and warrants further investigation. The role of MiP, particularly the NuMiP and OXPHOS pathways in RFI, was also supported by our gene correlation network analysis and the hub gene identification. We validated the findings in an independent data set. Overall, our study suggested that differences in feed efficiency in dairy cows may be linked to differences in cellular energy demand. This study broadens our knowledge of the biology of feed efficiency in dairy cattle.     

Antioxidant activity of carotenoids against the oxidative destabilization of sunflower oil-in-water emulsions

The antioxidant activity of carotenoids (β-carotene, lycopene, paprika, marigold, bixin- and norbixin-rich annatto extracts) was estimated in sunflower oil-in-water emulsions (o/w) stabilized either by Tween 20 or by a mixture of Tween 20 and sodium caseinate at equal concentrations. Both polar (paprika, marigold, bixin, norbixin) and hydrophobic (β-carotene, lycopene) carotenoids exerted a clear antioxidant effect during thermal accelerated autoxidation (60 °C) of o/w emulsions stabilized by Tween 20, while in the protein-based emulsions only polar carotenoids acted as antioxidants against the production of primary and secondary oxidation products. Furthermore, o/w emulsions, containing different concentration of paprika and bixin-rich annatto extract (0.25–1.5 g/L) in the lipid phase oxidized slower than the control emulsions. Meanwhile, the rate of carotenoids' degradation revealed that polar carotenoids, which presented antioxidant effect in both protein and Tween 20 stabilized emulsions, presented a higher rate of degradation than the hydrophobic carotenoids.     

Antimicrobial activity of potassium hydroxide and lauric acid against microorganisms associated with poultry processing

The antimicrobial activity of solutions of potassium hydroxide (KOH) and mixtures of KOH and lauric acid against microorganisms associated with poultry processing was determined. In vitro tests were performed by enumerating viable microorganisms recovered from bacterial cultures suspended in peptone water (control) and in solutions of 0.1% KOH or mixtures of 0.1% KOH and 0.25 or 0.50% lauric acid. Additional studies were conducted to identify changes in the native microbial flora of poultry skin washed in distilled water, KOH, or KOH-lauric acid. Although results of in vitro studies indicated that significantly fewer bacteria (P < or = 0.05) were recovered from cultures suspended in KOH than from cultures suspended in peptone water, there were also significantly fewer bacteria recovered from cultures suspended in KOH-lauric acid than from cultures suspended in KOH. Results of experiments with broiler skin indicated that although rinsates of skin washed in 1.0% KOH solutions contained significantly fewer total aerobic bacteria and enterococci than did skin washed in water, significantly fewer of these microorganisms were generally recovered from rinsates of skin washed in mixtures of 1.0% KOH and 0.5, 1.0, 1.5, or 2.0% lauric acid than from skin washed in KOH alone. Washing of broiler skin in solutions of 0.25 to 1.00% KOH or mixtures containing these concentrations of KOH and two parts lauric acid (wt/vol) also significantly reduced the populations of bacteria and yeasts in the native flora of broiler skin. Enterococci, lactic acid bacteria, and staphylococci in the native flora of the skin had the highest level of resistance to the bactericidal activity of KOH-lauric acid. These findings indicate that the antimicrobial activity of KOH-lauric acid is significantly greater than that of KOH alone in vitro and on poultry skin. Thus, KOH-lauric acid may be useful for reducing the level of microbial contamination associated with poultry processing.     

Isolation of lactic acid bacteria with inhibitory activity against pathogens and spoilage organisms associated with fresh meat

The use of lactic acid bacteria (LAB) as protective cultures in vacuum-packed chill-stored meat has potential application for assuring and improving food quality, safety and market access. In a study to identify candidate strains suitable for evaluation in a meat model, agar-based methods were employed to screen 181 chilled meat and meat process-related LAB for strains inhibitory to pathogens and spoilage organisms of importance to the meat industry. Six meat-derived strains, including Lactobacillus sakei and Lactococcus lactis, were found to be inhibitory to one or more of the target strains Listeria monocytogenes, Brochothrix thermosphacta, Campylobacter jejuni and Clostridium estertheticum. The inhibitory agents appeared to be either cell-associated or molecules released extracellularly with bacteriocin-like properties. Variations detected in the antimicrobial activity of LAB associated with changes to test parameters such as substrate composition underlined the importance of further in situ evaluation of the inhibitory strains in stored meat trials.     

Use of proteases to improve oxidative stability of fermented sausages by increasing low molecular weight compounds with antioxidant activity

Forty fermented sausages from Iberian pigs were manufactured using 3 different proteases with a potential antioxidant activity (batch 1: without proteases, batch 2: neutral bacterial protease, batch 3: fungal protease and batch 4: fungal protease concentrate). The antioxidant properties of extracts (< 3 kDa) from Iberian dry-cured sausages were assessed using four different methods: (i) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA), (ii) metal chelating assay (MQA), (iii) reducing power (RP) and (iv) inhibition of linoleic acid autoxidation (ILAA). Dry-cured sausage extracts from of all the manufactured batches showed antioxidant activity as indicated by RSA, MQA and ILAA. Manufacturing sausages with the used proteases increased the antioxidant activity of the sausage extracts, except for the MQA. Moreover, extracts from dry-cured sausages which were manufactured without proteases showed the highest levels of both thiobarbituric acid-reactive substances (TBARs) and hexanal content.     

Proteolytic activity of Saccharomyces cerevisiae strains associated with Italian dry-fermented sausages in a model system

Strains of Saccharomyces cerevisiae isolated from Italian salami were screened for proteolytic activity in a model system containing sarcoplasmic (SMS) or myofibrillar (MMS) proteins, at 20 °C for 14 days, to evaluate the possible influence on the proteolysis of fermented sausages.SDS-PAGE revealed that 14 of the most osmotolerant strains were responsible for the extensive hydrolysis of the main myofibrillar proteins, while only one strain was able to hydrolyze sarcoplasmic proteins. Free amino acids (FAA) accumulated during proteolysis were strain-dependent with different patterns from sarcoplasmic or myofibrillar protein fraction. In general, proteolysis lead Cys, Glu, Lys and Val as the most abundant FAA in the inoculated MMS samples. Volatile compound analysis, determined by SPME-GC-MS, evidenced 3-methyl butanol in MMS, and 2-methyl propanol and 3-methyl-1-butanol in SMS as major compounds. Our findings highlight that S. cerevisiae could influence the composition in amino acids and volatile compounds in fermented sausages, with a strain-dependent activity.     

Efficient removal of estrogenic activity during oxidative treatment of waters containing steroid estrogens

The discharge of synthetic and natural steroid estrogens from municipal wastewaters to the aquatic environment has received increased attention because of their potential reproductive effects on fish. Using 17alpha-ethinylestradiol (EE2) as a representative steroid estrogen, several oxidants applied in wastewater treatment (chlorine, bromine, ozone, hydroxyl radical, chlorine dioxide, and ferrate) were shown to selectively and rapidly transform EE2. For typically applied oxidant doses, these transformations occur in the time range of seconds to minutes. The resulting initial transformation products of EE2 exhibit a substantially lower in vitro estrogenic activity (< 13% of EE2). For selected structural derivatives of EE2, a quantitative structure-activity relationship was established between substituents changed on the phenolic moiety and the relative in vitro estrogenic activity. In addition, the initial EE2 transformation products that still exhibit residual estrogenic activity are quickly further transformed by most of the tested oxidants. Therefore, oxidative wastewater treatment may serve as a powerful tool to remove estrogenic activity induced by steroid estrogens.     

Factors associated with estrous expression and subsequent fertility in lactating dairy cows using automated activity monitoring

The objective of this observational study was to identify factors associated with estrous duration (DU) and intensity measured as the peak of activity (PA) change and subsequent fertility in lactating Holstein cows using a neck-mounted automated activity monitor (Heatime Pro, SCR Engineers Ltd., Netanya, Israel). Ambient temperature and relative humidity were recorded hourly to calculate the temperature-humidity index (THI). A total of 5,933 estrus events from 3,132 cows located on 8 commercial dairy farms in Germany were used for this study. Farms participated in monthly DHIA testing. Pregnancy diagnosis was performed either by transrectal palpation [farm 1: 42 ± 3 d; farm 3: 40 ± 3 d; farms 4 and 8: 38 ± 3 d; farm 5: 43 ± 3 d after artificial insemination (AI)] or transrectal ultrasonography (farms 2, 6, and 7: 30 ± 3 d after AI). Estrous intensity was categorized based on peak activity of estrus into low (35–89 index value), and high (90–100 index value) PA. Overall, 73.5% of estrus events were of high PA. The mean (± standard error of the mean) DU was 14.94 ± 0.06 h. There was a strong correlation between DU and PA (r = 0.67). In the final statistical model, only PA was associated with pregnancy per artificial insemination (P/AI), with 1.35 greater odds of pregnancy for cows with high PA compared with cows with low PA. Increased THI 1 wk before AI was associated with shorter DU, lower PA, and decreased P/AI. A small percentage of cows (4.7%) showed short interestrus intervals (i.e., more than 1 activity peak within 7 d close to the event of estrus), resulting in reduced DU, PA, and P/AI. The change of weighted rumination was associated with DU and PA, as a lower nadir was associated with a greater risk for high PA and long DU. There was no association, however, between the nadir of change of weighted rumination and P/AI. Whereas milk yield and somatic cell count from the DHIA test date before AI were negatively associated with estrous expression, neither milk yield nor somatic cell count was associated with P/AI. Surprisingly, multiparous cows expressed estrus with longer DU (13.15 ± 0.31 h) compared with primiparous cows (12.52 ± 0.32 h), whereas PA did not differ among parities. Pregnancy per AI was greater for primiparous (29.4%) than for multiparous (22.1%) cows. An estrus event with long DU or high PA was more likely later in lactation. Milk fat, milk protein, milk urea nitrogen, and lactose from the DHIA test date closest to AI had no association with estrous expression or P/AI. In conclusion, DU and PA were highly correlated, and cows with high PA were particularly associated with greater odds for pregnancy. A negative association between estrous expression and P/AI was identified for increased THI 1 wk before AI and cows with short interestrus intervals using automated activity monitor.