Effect of the feeding system on the fatty acid composition,expression of the Δ<Superscript>9</Superscript>-desaturase,Peroxisome Proliferator-Activated Receptor Alpha,Gamma, and Sterol Regulatory Element Binding Protein 1 genes in the semitendinous muscle of light lambs of the Rasa Aragonesa breed

Background  

Conjugated linoleic acids (CLAs) are receiving increasing attention because of their beneficial effects on human health, with milk and meat products derived from ruminants as important sources of CLA in the human diet. SCD gene is responsible for some of the variation in CLA concentration in adipose tissues, and PPARγ, PPARα and SREBP1 genes are regulator of SCD gene. The aim of this work was to evaluate the effect of the feeding system on fatty acid composition, CLA content and relative gene expression of Δ⁹-desaturase (SCD), Peroxisome Proliferator-Activated Receptor Gamma (PPARγ), Peroxisome Proliferator-Activated Receptor Alpha, (PPARα) and Sterol Regulatory Element Binding Protein (SREBP1) in Rasa Aragonesa light lambs in semitendinous muscle. Forty-four single-born male lambs were used to evaluate the effect of the feeding system, varying on an intensity gradient according to the use of concentrates: 1. grazing alfalfa, 2. grazing alfalfa with a supplement for lambs, 3. indoor lambs with grazing ewes and 4. drylot.     

Conversion of t11t13 CLA into c9t11 CLA in Caco-2 cells and inhibition by sterculic oil

Background

Conjugated linoleic acids (CLA), and principally c9t11 CLA, are suspected to have numerous preventive properties regarding non-infectious pathologies such as inflammatory diseases, atherosclerosis and several types of cancer. C9t11 CLA is produced in the rumen during biohydrogenation of linoleic acid, but can also be synthesized in mammalian tissues from trans-vaccenic acid (C18:1 t11) through the action of delta-9 desaturase (D9D). For several years, it is also known that c9t11 CLA can be synthesized from conjugated linolenic acids (CLnA), i.e. c9t11c13 CLnA and c9t11t13 CLnA. This study aimed at investigating to which extent and by which route c9t11 CLA can be produced from another isomer of CLA, the t11t13 CLA that is structurally very similar to c9t11t13 CLnA, in Caco-2 cells.

Methodology/Principal Findings

Caco-2 cells were incubated for 24 h with 20 µmol/l of t11t13 CLA in the absence or presence of sterculic oil used as an inhibitor of D9D. Caco-2 cells were able to convert t11t13 CLA into c9t11 CLA, and c9t11t13 CLnA was formed as an intermediate compound. In the presence of sterculic oil, the production of this intermediate was decreased by 46% and the formation of c9t11 CLA was decreased by 26%. No other metabolite was detected.

Conclusions/Significance

These results not only highlight the conversion of t11t13 CLA into c9t11 CLA but demonstrate also that this conversion involves first a desaturation step catalysed by D9D to produce c9t11t13 CLnA and then the action of another enzyme reducing the double bond on the Δ13 position.     

Effect of diets supplemented with different conjugated linoleic acid (CLA) isomers on protein expression in C57/BL6 mice

Background

The individual genetic variations, as a response to diet, have recently caught the attention of several researchers. In addition, there is also a trend to assume food containing beneficial substances, or to supplement food with specific compounds. Among these, there is the conjugated linoleic acid (CLA), which has been demonstrated to reduce fat mass and to increase lean mass, even though its mechanism of action is still not known. We investigated the effect of CLA isomers (CLA c9,t11 and CLA t10,c12) on the proteomic profile of liver, adipose tissue, and muscle of mouse, with the aim of verifying the presence of a modification in fat and lean mass, and to explore the mechanism of action.

Methods

C57/BL6 mice were fed for 2 months with different diets: (1) standard chow, (2) CLA c9,t11 diet, (3) CLA t10,c11 diet, (4) CLA isomers mixture diet, and (5) linoleic acid diet. The proteomic profile of liver, white adipose tissue, and muscle was investigated. Statistical significance of the spots with an intensity higher than twofold in expression compared to the control was tested using student’s t test (two-tail).

Results

We found that both isomers modulate the proteomic profiles of liver, adipose tissue, and muscle by different mechanisms of action. Liver steatosis is mostly due to the isomer CLA t10,c12, since it alters the expression of lipogenetic proteins; it acts also reducing the adipose tissue and increasing fatty acid oxidation in muscle. Conversely, CLA c9,t11 has no relevant effects on liver and adipose tissue, but acts mostly on muscle, where it enhances muscular cell differentiation.

Conclusions

Administration of CLA in humans has to be carefully personalized, since even considering the presence of a species-specific effect, adverse effects might occur on long-term supplementation. Here we demonstrated that, in mouse, CLA is effective in reducing fat mass, but it also induces liver steatosis. The increase of lean mass is linked to an induction of cell proliferation, which, on long-term supplementation, might also lead to adverse effects.

     

Probiotic bacteria produce conjugated linoleic acid locally in the gut that targets macrophage PPAR γ to suppress colitis

Background

Inflammatory bowel disease (IBD) therapies are modestly successful and associated with significant side effects. Thus, the investigation of novel approaches to prevent colitis is important. Probiotic bacteria can produce immunoregulatory metabolites in vitro such as conjugated linoleic acid (CLA), a polyunsaturated fatty acid with potent anti-inflammatory effects. This study aimed to investigate the cellular and molecular mechanisms underlying the anti-inflammatory efficacy of probiotic bacteria using a mouse model of colitis.

Methodology/Principal Findings

The immune modulatory mechanisms of VSL#3 probiotic bacteria and CLA were investigated in a mouse model of DSS colitis. Colonic specimens were collected for histopathology, gene expression and flow cytometry analyses. Immune cell subsets in the mesenteric lymph nodes (MLN), spleen, blood and colonic lamina propria cells were phenotypically and functionally characterized. Fecal samples and colonic contents were collected to determine the effect of VSL#3 and CLA on gut microbial diversity and CLA production. CLA and VSL#3 treatment ameliorated colitis and decreased colonic bacterial diversity, a finding that correlated with decreased gut pathology. Colonic CLA concentrations were increased in response to probiotic bacterial treatment, but without systemic distribution in blood. VSL#3 and CLA decreased macrophage accumulation in the MLN of mice with DSS colitis. The loss of PPAR γ in myeloid cells abrogated the protective effect of probiotic bacteria and CLA in mice with DSS colitis.

Conclusions/Significance

Probiotic bacteria modulate gut microbial diversity and favor local production of CLA in the colon that targets myeloid cell PPAR γ to suppress colitis.     

Seasonal variations in fatty acid composition of pasture forage plants and CLA content in ewe milk fat

The relations between fatty acids (FAs) composition of pasture forage plants and the content of conjugated linoleic acid (CLA) as a total content of cis-9, trans-11 + trans-7, cis-9 + trans-8, cis-10 CLA isomers in ewes’ milk fat during natural pasture season (April–September) were investigated. The extracts of ewes’ milk fat samples as well as the pasture samples were analyzed for fatty acid composition by capillary gas chromatography with flame ionization and mass spectrometric detection. α-Linolenic, linoleic, and palmitic acids were predominant in pasture plants, and their contents varied during pasture season. The most abundant and most varied fatty acid compound in pasture plants was α-linolenic acid. Its content significantly decreased from 62% to 39% (of total FA) (P < 0.001) from May to August, and subsequently it slightly (57%) increased from August to September (P < 0.05), compared with the beginning of pasture season. Similarly, the content of CLA in ewes’ milk fat decreased from 2.4% in May to 1.3% in August (P < 0.001), and subsequently it rose to 2.6% in September (P < 0.001). The α-linolenic/linoleic acid ratio in the pasture sample decreased from 4.36 in May to 1.97 in August (P < 0.001), and subsequently it increased to 3.14 in September (P < 0.001); thus, it reached the level approaching to that at the beginning of pasture season. The pasture seasonal variations in the ratio were directly proportional to the corresponding content of CLA and indirectly proportional to the ratio in ewes’ milk fat. The results suggest that the seasonal variations in CLA content in ewes’ milk fat are related primarily to the seasonal variation in α-linolenic acid content in grass lipids.     

Expression of adipose microRNAs is sensitive to dietary conjugated linoleic acid treatment in mice

Background

Investigation of microRNAs (miRNAs) in obesity, their genetic targets and influence by dietary modulators is of great interest because it may potentially identify novel pathways involved in this complex metabolic disorder and influence future therapeutic approaches. This study aimed to determine whether miRNAs expression may be influenced by conjugated linoleic acid (CLA), currently used to induce fat loss.

Methodology/Principal Findings

We determined retroperitoneal adipose tissue (rWAT) expression of five miRNAs related to adipocyte differentiation (miRNA-143) and lipid metabolism (miRNA-103 and -107) and altered in obesity (miRNA-221 and -222), using the TaqMan®MicroRNA Assay (Applied-Biosystems). In the first experiment, mice were fed with a standard fat diet and orally treated with sunflower oil (control group) and 3 or 10 mg CLA/day for 37 days. In the second experiment, mice were fed with a high fat diet for 65 days. For the first 30 days, mice received the same doses of CLA described above and, from that time onwards, animals received a double dose. Results showed that expression of selected miRNAs was modified in response to CLA treatment and metabolic status. Interestingly, a strong correlation was observed between miR-103 and -107 expression, as well as miR-221 and -222 in both experiments. Moreover, changes in miRNAs expression correlated with several adipocyte gene expressions: miR-103 and -107 correlated with genes involved in fatty acid metabolism whereas miR-221 and miR-222 correlated with the expression of adipocytokines. Regarding the minor changes observed in miR-143 expression, no differences in expression of adipogenic markers were observed.

Conclusions/Significance

Although elucidating the functional implications of miRNAs is beyond the scope of this study, these findings provide the first evidence that miRNAs expression may be influenced by dietary manipulation, reflecting or even contributing to the new metabolic state originated by CLA treatment.     

Influence of organic systems on milk fatty acid profile and CLA in goats

The effect of organic system on the fatty acid profile of milk and CLA content was evaluated using 30 pregnant pluriparous goats, divided into two homogeneous groups (S and O) of 15 goats each. Group S was housed in a stable and received alfalfa hay as forage, while group O was raised according EC Regulation 834/2007 and led to pasture. After the kids weaning, goats were milked twice a day for 5 months. Daily milk yield was recorded and, monthly, representative milk samples from the two daily milkings were analysed for chemical and fatty acid profile. Average milk yield did not differ statistically between the groups. The goats of the O group had significantly higher fat content in milk than those of group S (65.9 g/day vs. 54.3 g/day, P < 0.01). Among milk fatty acids, organic system significantly affected the percentages of C18:1 c9, C18:1 t11, linoleic acid, alpha-linolenic acid, monounsaturated fatty acid and polyunsaturated fatty acid. Organic system highly influenced the c9 t11 conjugated linoleic acid (CLA) (0.810 g/100 g of fat vs. 0.542 g/100 g of fat, for groups O and S, respectively, P < 0.01), t10 c12 CLA (0.041 g/100 g of fat vs. 0.024 g/100 g of fat, for groups O and S, respectively, P < 0.01) and ∑CLA (0.87 g/100 g of fat vs. 0.58 g/100 g of fat for groups O and S, respectively, P < 0.01) concentrations of milk.     

Immunoregulatory mechanisms underlying prevention of colitis-associated colorectal cancer by probiotic bacteria

Background

Inflammatory bowel disease (IBD) increases the risk of colorectal cancer. Probiotic bacteria produce immunoregulatory metabolites in vitro such as conjugated linoleic acid (CLA), a polyunsaturated fatty acid with potent anti-carcinogenic effects. This study aimed to investigate the cellular and molecular mechanisms underlying the efficacy of probiotic bacteria in mouse models of cancer.

Methodology/Principal Findings

The immune modulatory mechanisms of VSL#3 probiotic bacteria and CLA were investigated in mouse models of inflammation-driven colorectal cancer. Colonic specimens were collected for histopathology, gene expression and flow cytometry analyses. Immune cell subsets in the mesenteric lymph nodes (MLN), spleen and colonic lamina propria lymphocytes (LPL) were phenotypically and functionally characterized. Mice treated with CLA or VSL#3 recovered faster from the acute inflammatory phase of disease and had lower disease severity in the chronic, tumor-bearing phase of disease. Adenoma and adenocarcinoma formation was also diminished by both treatments. VSL#3 increased the mRNA expression of TNF-α, angiostatin and PPAR γ whereas CLA decreased COX-2 levels. Moreover, VSL#3-treated mice had increased IL-17 expression in MLN CD4+ T cells and accumulation of Treg LPL and memory CD4+ T cells.

Conclusions/Significance

Both CLA and VSL#3 suppressed colon carcinogenesis, although VSL#3 showed greater anti-carcinogenic and anti-inflammatory activities than CLA. Mechanistically, CLA modulated expression of COX-2 levels in the colonic mucosa, whereas VSL#3 targeted regulatory mucosal CD4+ T cell responses.     

Effect of fish oil and sunflower oil supplementation on milk conjugated linoleic acid content for grazing dairy cows

The objective of this study was to determine the effect of adding fish oil (FO) and sunflower oil (SFO) to grazing dairy cows’ diets on the temporal changes in milk conjugated linoleic acid (cis-9, trans-11 CLA). Sixteen Holstein cows were divided into two diet regimen groups. One group (CONT) was fed a basal diet (7.6 kg DM basis) plus 400 g animal fat. The other group (FOSFO) were fed a basal diet plus 100 g of FO and 300 g of SFO (FOSFO). The cows were milked twice a day and milk samples were collected every 3-day for a period of 21 days. Both groups grazed together on pasture ad libitum and fed treatment diets after the morning and afternoon milking. Milk production, milk fat percentages, milk fat yield, milk protein percentages, and milk protein yield were not affected (P>0.05) by treatment diets. The concentrations of cis-9 trans-11 CLA and vaccenic acid (VA) in milk fat were higher (P<0.05) for cows fed the FOSFO over 3 week of lipid supplementation. The concentration of cis-9 trans-11 CLA in milk fat reached maximum on day 3 with both diets and remained relatively constant thereafter. The concentration of VA in milk fat followed the same pattern of temporal changes as cis-9 trans-11 CLA. In conclusion, milk cis-9, trans-11 CLA and VA concentrations increased with FO and SFO supplementation compared with the CONT diet and the increase reached a plateau on day 3 of supplementation and remained relatively constant throughout the remainder of the study.     

Effect of conjugated linoleic acid on dietary lipids utilization, liver morphology and selected immune parameters in sea bass juveniles (Dicentrarchus labrax)

Increased energy content in fish feeds has led to an enhanced fat deposition, particularly in European sea bass, concerning fish farmers. Inclusion of conjugated linoleic acid (CLA) could reduce fat deposition as in other vertebrates. To determine if dietary CLA affects fat deposition, lipid metabolism, lipid composition and morphology of different tissues, growth and selected immune parameters, European sea bass juveniles were fed 4 graded levels of CLA (0, 0.5, 1 and 2%). Growth and feed conversion were not affected by CLA, whereas feed intake was reduced (P < 0.05) by feeding 2% CLA. In these fish perivisceral fat was also reduced (P < 0.05), particularly reducing (P < 0.05) monounsaturated fatty acids. CLA has not affected tissue proximal composition, but reduced (P < 0.05) saturated and monounsaturated fatty acids and increased (P < 0.05) the n−3 and n−3 highly unsaturated fatty acids in muscle and increase (P < 0.05) CLA content in muscle, liver and perivisceral fat. A progressive reduction in lipid vacuolization of hepatocytes cytoplasm and regular-shaped morphology was found in fish fed increased CLA levels, together with a progressive increase in malic enzyme activity (only significant in fish fed 1% CLA). Finally, inclusion of CLA up to 1% increased (P < 0.05) plasma lysozyme activity and was positively correlated with alternative complement pathway.     

Whole genome sequencing reveals novel genetic mutations of Helicobacter pylori associating with resistance to clarithromycin and levofloxacin

Background

Detection of mutations in one or a couple of genes may not provide enough data or cover all the genomic DNA variance related to antibiotic resistance of Helicobacter pylori to clarithromycin (CLA) and levofloxacin (LVX). We aimed to perform whole genome sequencing to explore novel antibiotic resistance-related genes to increase predictive accuracy for future targeted sequencing tests.

Methods

Gastric mucosal biopsies were taken during upper endoscopy in 27 H. pylori-infected patients. According to culture-based antibacterial susceptibility test, H. pylori strains were divided into three groups, with nine strains in each group: CLA single-drug resistance (group C), LVX single-drug resistance (group L), and strains sensitive to all antibacterial drugs (group S). Based on whole genome sequencing with group S being the control, group C and group L group-specific single nucleotide variants and amino acid mutations were screened, and potential candidate genes related to CLA and LVX resistance were identified.

Results

The median age of study subjects was 35 years (IQR: 31–40), and 17 (63.0%) were male. All nine CLA-resistant strains had A2143G mutations in 23S rRNA, while none of nine sensitive strains had the mutation. Six of nine strains in group L and six of nine strains in group S had 87th or 91st mutation in gyrA. After comparing sequencing data of strains among the three groups, we identified five mutated positions belonging to four genes related to CLA resistance, and 31 mutated positions belonging to 20 genes related to LVX resistance. Novel genetic mutations were detected for CLA resistance (including fliJ and clpX) and LVX resistance (including fliJ, cheA, hemE, Val360Ile, and HP0568). Missense mutations in fliJ and cheA gene were mainly involved in chemotaxis and flagellar motility to facilitate bacterial escape of antibiotics, while the functions of other novel gene mutations underpinning antibiotic resistance remain to be investigated.

Conclusion

Whole genome sequencing detected potential novel genetic mutations conferring resistance of H. pylori to CLA and LVX including fliJ and cheA. Further studies to correlate these findings with treatment outcome should be performed.     

Effects of dietary sources of vegetable fats on performance of dairy ewes and conjugated linoleic acid (CLA) in milk

Two experiments were carried out to study the effects of supplementing the ration of lactating ewes with vegetable fats (sunflower oil, SO or hydrogenated palm oil, HPO; HIDROPALM^®) on diet digestibility, milk yield and milk composition, and on the concentration of the conjugated linoleic acid (CLA) C18:2 cis-9 trans-11 and C18:1 trans-11 (vaccenic acid, VA) and other main fatty acids in milk fat. Treatments involved a control diet, without added oil, and 2 diets supplemented with either 12 g/kg SO or 12 g/kg HPO on a dry matter (DM) basis. In the first experiment, 6 non-pregnant, non-lactating Lacaune ewes were used following a 3 × 3 replicated Latin Square design. Addition of vegetable fat supplement to the diet increased digestibility of DM, organic matter (OM) and crude protein (CP), but did not affect that of the ether extract (EE), neutral detergent fibre (NDF) or acid detergent fibre (ADF). In the second experiment, 60 Lacaune dairy ewes mid-way through lactation (120 ± 12 days in milk, 0.98 ± 0.03 kg/day average milk yield) were divided into three equal-sized groups each of which was assigned to one of the three experimental diets for 4 weeks. Compared with the control treatment, supplementation with HPO increased milk yield and energy-corrected milk. But neither vegetable fat supplement modified percentages of fat and protein in milk. Supplementation with HPO increased C14:1, C16:1 and C16:0 content and reduced C18:0 and C18:1 cis-9 content in milk fat. Supplementation with SO increased the VA content in milk fat by 36% and that of cis-9 trans-11 CLA by 29% in comparison with the control diet. Supplementation with HPO led to milk fat with 15% more cis-9 trans-11 CLA than control milk. In conclusion, adding a moderate dose of HPO or SO to the diets increased CLA concentration in milk fat. Nevertheless, supplementation with SO was more effective than HPO in increasing CLA concentration in milk fat and reducing the atherogenicity index, improving milk quality from the human health standpoint.     

Effect of a High Intake of Conjugated Linoleic Acid on Lipoprotein Levels in Healthy Human Subjects

Background

Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower high-density lipoprotein (HDL) cholesterol, raise low-density lipoprotein (LDL) cholesterol, and increase the risk of coronary heart disease. The effects of trans fatty acids from ruminants are less clear. We investigated the effect on blood lipids of cis-9, trans-11 conjugated linoleic acid (CLA), a trans fatty acid largely restricted to ruminant fats.

Methodology/Principal Findings

Sixty-one healthy women and men were sequentially fed each of three diets for three weeks, in random order, for a total of nine weeks. Diets were identical except for 7% of energy (approximately 20 g/day), which was provided either by oleic acid, by industrial trans fatty acids, or by a mixture of 80% cis-9, trans-11 and 20% trans-10, cis-12 CLA. After the oleic acid diet, mean (± SD) serum LDL cholesterol was 2.68±0.62 mmol/L compared to 3.00±0.66 mmol/L after industrial trans fatty acids (p<0.001), and 2.92±0.70 mmol/L after CLA (p<0.001). Compared to oleic acid, HDL-cholesterol was 0.05±0.12 mmol/L lower after industrial trans fatty acids (p = 0.001) and 0.06±0.10 mmol/L lower after CLA (p<0.001). The total-to–HDL cholesterol ratio was 11.6% higher after industrial trans fatty acids (p<0.001) and 10.0% higher after CLA (p<0.001) relative to the oleic acid diet.

Conclusions/Significance

High intakes of an 80∶20 mixture of cis-9, trans-11 and trans-10, cis-12 CLA raise the total to HDL cholesterol ratio in healthy volunteers. The effect of CLA may be somewhat less than that of industrial trans fatty acids.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00529828","term_id":"NCT00529828"}}NCT00529828     

Production of conjugated linoleic acid and conjugated linolenic acid isomers by Bifidobacterium species

Conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA) isomers have attracted great interest because of their potential health benefits. Formation of CLA and CLNA takes place in the rumen during biohydrogenation. Several studies have indicated that certain types of intestinal bacteria, including bifidobacteria, are able to convert linoleic acid (LA) to CLA. The role of intestinal bacteria in the formation of CLNA isomers is largely unknown. In the present study, a screening of 36 different Bifidobacterium strains for their ability to produce CLA and CLNA from free LA and α-linolenic acid (LNA), respectively, was performed. The strains were grown in MRS broth, to which LA or LNA (0.5 mg ml⁻¹) were added after 7 h of bacterial growth. Cultures were further incubated at 37°C for 72 h. Six strains (four Bifidobacterium breve strains, a Bifidobacterium bifidum strain and a Bifidobacterium pseudolongum strain) were able to produce different CLA and CLNA isomers. Conversion percentages varied from 19.5% to 53.5% for CLA production and from 55.6% to 78.4% for CLNA production among these strains. The CLA isomers produced were further identified with Ag⁺-HPLC. LA was mainly converted to t9t11-CLA and c9t11-CLA. The main CLNA isomers were identified with GC-MS as c9t11c15-CLNA and t9t11c15-CLNA.     

Accumulation of conjugated linoleic acid in <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> WU-P19 is enhanced by induction with linoleic acid and chitosan treatment

Production of conjugated linoleic acid (CLA) by the potential probiotic bacterium Lactobacillus plantarum WU-P19 was investigated with the aim of enhancing production. CLA produced using this bacterium may be used to supplement dietary intake. Cultures were fed linoleic acid for conversion to CLA and the CLA produced was measured. In some cases, chitosan was added to cultures to improve cellular uptake of linoleic acid. Under static conditions at 37 °C, the bacterium grew and produced CLA in the pH range of 5.5–6.5. At pH 6.0, a 36-h incubation period maximized the concentration of the dry biomass (0.82 g/L), the CLA content in the biomass (4.1 mg/g), and linoleic acid in the biomass (1.2 mg/g). In comparison with cultures grown without linoleic acid in the medium, supplementing the medium with linoleic acid at 600 μg/mL slowed the production of CLA, but the CLA content in the dry biomass increased to 12–14 mg/g and the linoleic acid content increased to 8–11 mg/g. Supplementing the culture medium with chitosan and linoleic acid enhanced production of CLA in the dry biomass to 21 mg/g within 36 h. Nearly 50% of the CLA was cis-9, trans-11-CLA, and the remainder was trans-10, cis-12-CLA. Linoleic acid content of the dry biomass was increased to 37 mg/g. Accumulation of CLA in the cells was enhanced by feeding linoleic acid. Supplementing the culture with linoleic acid and chitosan further increased accumulation of CLA.     

SeqX: a tool to detect,analyze and visualize residue co-locations in protein and nucleic acid structures

Background  

The interacting residues of protein and nucleic acid sequences are close to each other – they are co-located. Structure databases (like Protein Data Bank, PDB and Nucleic Acid Data Bank, NDB) contain all in0066ormation about these co-locations; however it is not an easy task to penetrate this complex information. We developed a JAVA tool, called SeqX for this purpose.     

Antilisterial activity of lactose monolaurate in milk,drinkable yogurt and cottage cheese

Lactose monolaurate (LML) was previously found to be an antimicrobial against Listeria monocytogenes in culture medium at concentrations between 3 and 5 mg ml^?1. In this study, the microbial inhibitory activity of LML in dairy products inoculated with a 5‐strain cocktail of clinical isolates of L. monocytogenes was investigated. Addition of LML at a concentration of 5 mg ml^?1 resulted in 4·4, 4·0 and 4·2 log reductions in 0·5% fat, 1% fat and 3·25% fat milks, respectively; 4·1, 4·4, and 3·5 log reductions in nonfat, 1% fat, and 1·5% fat yogurts, respectively; and 4·0 log reductions in both nonfat and 2% fat cottage cheese. The inhibitory effect of LML was only observed at 37°C and not 5°C. Experiments suggest that both the lauric acid and the esterified lactose moiety of LML play roles in the growth inhibition.

Significance and Impact of the Study

A novel sugar ester, lactose monolaurate, inhibited the growth of a five‐strain cocktail of Listeria monocytogenes in milk, yogurt and cottage cheese. This is the first report of the use of a sugar ester to inhibit the growth of Listeria in food systems.     

Effect of dietary conjugated linoleic acid on serum levels of N2O5 and l-citrulline in goat kids

Forty new born male kids were allotted into two groups for the evaluation of the effects of dietary conjugated linoleic acid (CLA) on nitric oxide (NO) and l-citrulline levels in serum. The control group received no supplement CLA and the CLA group received 20 g/kg milk DM of CLA from birth to 1-month old. The kids were fed colostrum for 2 days and milk replacer from days 3 to 29. Blood samples (n = 40) were taken at 1, 8, 15, 22, and 29 days of age. N₂O₅ (nitrite + nitrate) concentration in serum ranged from 21.93 to 26.15 and 34.90 to 40.59 μmol in control and CLA kids. The l-citrulline values ranged from 0.30 to 0.40 and 15.54 to 19.81 μmol in control and CLA kids.     

Serum levels of appetite-regulating hormones and pro-inflammatory cytokines are ameliorated by a CLA diet and endurance exercise in rats fed a high-fat diet

[Purpose]

This study examined whether conjugated linoleic acid (CLA) supplementation and endurance exercise affect appetite-regulating hormones and pro-inflammatory cytokines in rats.

[Methods]

Seven-week-old male Sprague-Dawley rats were divided randomly into the high-fat diet sedentary group (HS, n=8), the 1.0% CLA supplemented high-fat diet sedentary group (CS, n=8), and the 1.0% CLA supplemented high-fat diet exercise group (CE, n=8). Rats in the CE group swam 60 min/day, 5 days/week for 4 weeks.

[Results]

Leptin and insulin levels in the CS and CE groups were significantly lower than those in the HS group (p<0.001), whereas leptin (p<0.01) and insulin (p<0.05) levels decreased significantly in the CE compared to those in the CS group. Interleukin (IL)-1β (p<0.001) and IL-6 (p<0.01) levels in the CS and CE groups decreased significantly compared to those in the HS group. Leptin (IL-1β: r=0.835, p<0.001), IL-6 (r=0.607, p<0.05), insulin (IL-1β: r=0.797, p<0.01), and IL-6 (r=0.827, p<0.01) levels were positively related with pro-inflammatory cytokine levels.

[Conclusion]

Endurance exercise may play an important role during CLA supplementation of rats on a high-fat diet.     

Comparative studies on the metabolism of linoleic acid by rumen bacteria,protozoa, and their mixture in vitro

Linoleic acid was differentially catabolized by the various rumen microbial fractions, such as rumen bacteria (B), protozoa (P), and their mixture (BP). The predominant isomer of conjugated linoleic acids (CLA) synthesized by B, P, and BP from linoleic acid was 9c11t-CLA. The formation of 9c11t-CLA was higher (P < 0.05) in P suspension (53.6 μg/mg microbial nitrogen) compared with B (38.3 μg/mg microbial nitrogen) and BP (28.8 μg/mg microbial nitrogen) suspensions by 12 h of incubation. The second most abundant CLA isomer was 10t12c. The accumulation of 10t12c-CLA in BP suspension was 2.3 times lower (P < 0.05) than that in B suspension (84.8 μg/mg microbial nitrogen) by 12 h of incubation. The accumulation of 10t-18:1 in BP suspension during 6- and 12-h incubation periods were not different (P > 0.05) than that in B suspension (6.8 and 14.0 μg/mg microbial nitrogen, respectively). However, the accumulation of 11t-18:1 in BP suspension at 6- and 12-h incubations were 2.7 and 3.3 times higher (P < 0.05), respectively, than that in B suspension. There were no significant accumulations of 11t-18:1, 10t-18:1, and 18:0 in P suspension throughout the incubation period. It was concluded that B, P, and BP metabolized linoleic acid to different isomers of CLA, whereas B, including BP, was only capable of biohydrogenating the CLA isomers to 18:0 by the reduction of 18:1 isomers. P was incapable of biohydrogenating LA, but its association with B in the BP suspension altered the biohydrogenation of LA significantly compared with B alone.