Effects of chronic caloric restriction on kidney and heart redox status and antioxidant enzyme activities in Wistar rats

Caloric restriction (CR) has been associated with health benefits and these effects have been attributed, in part, to modulation of oxidative status by CR; however, data are still controversial. Here, we investigate the effects of seventeen weeks of chronic CR on parameters of oxidative damage/modification of proteins and on antioxidant enzyme activities in cardiac and kidney tissues. Our results demonstrate that CR induced an increase in protein carbonylation in the heart without changing the content of sulfhydryl groups or the activities of superoxide dismutase and catalase (CAT). Moreover, CR caused an increase in CAT activity in kidney, without changing other parameters. Protein carbonylation has been associated with oxidative damage and functional impairment; however, we cannot exclude the possibility that, under our conditions, this alteration indicates a different functional meaning in the heart tissue. In addition, we reinforce the idea that CR can increase CAT activity in the kidney. [BMB Reports 2012; 45(11): 671-676]     

MOLECULAR CLONING OF TRYPSIN AND THE EFFECT OFDIETARY PROTEIN LEVELS AND STARVATION ON TRYPSINmRNA EXPRESSION AND ENZYME ACTIVITY IN JUVENILECHINESE SUCKER (MYXOCYPRINUS ASIATICUS BLEEKER)

The effect of dietary protein and starvation on the expression of trypsin was evaluated in the Chinesesucker (Myxocyprinus asiaticus Bleeker). The complete trypsin cDNA was cloned from juvenile Chinese suckerpancreatic tissue by using RACE and PCR methods. We used semi-quantitative RT-PCR and enzymatic activitymeasurements to quantify mRNA expression and trypsin activity in fish that were either starved or fed differinglevels of dietary casein (35%, 45% and 55%). The results showed that the Chinese sucker trypsin cDNA sequencewas 912 bp in length. Trypsin activity and mRNA levels were higher in fish that were fed moderate (45% casein)levels of protein than those that were fed high or low levels. Starvation significantly decreased mRNA expressionlevel and trypsin activity. The changes in trypsin activity tended to lag behind the changes in mRNA levels. Therewas no direct relationship between the trypsin activity and mRNA level. Given this, the trypsin synthesis is acomplex process regulated by a balance of several factors in the Chinese sucker.     

Assessment of dietary exposure related to dietary GI and fibre intake in a nutritional metabolomic study of human urine

There is a need for a tool to assess dietary intake related to the habitual dietary glycaemic index (GI) and fibre in groups with large numbers of individuals. Novel metabolite-profiling techniques may be a useful approach when applied to human urine. In a long-term, controlled dietary intervention study, metabolomics were applied to assess dietary patterns. A targeted approach was used to evaluate the effects on urinary C-peptide excretion caused by the dietary treatments. Seventy-seven overweight subjects followed an 8-week low-calorie diet (LCD) and were then randomly assigned to a high-GI or low-GI diet for 6 month during which they completed 24-h urine collections at baseline (prior to the 8-week LCD) and after randomisation to the dietary intervention, at month 1, 3 and 6, respectively. Metabolite profiling in 24-h urine was performed by ¹H NMR and chemometrics. Partial least squares (PLS) analysis indicated that urinary formate could discriminate between high-GI and low-GI diets (correlation coefficient r = 0.82), and this finding was confirmed statistically (P = 0.01). PLS analysis also indicated that urinary hippurate could be associated with fibre intake, but this finding was not confirmed statistically. No associations between GI and urinary C-peptide were found. Our results emphasise that application of metabolomics is useful in the assessment of dietary exposure related to dietary GI and fibre seen at group level in a nutritional metabolomic study of human urine. As our design allowed for large variations in individually selected food items, biomarkers identified at group level may be interpreted as more general and robust markers, largely not confounded with markers from single dietary factors.     

Chitosan influence on glucose and calcium availability from yogurt: In vitro comparative study with plants fibre

Since chitosan complies with the definition of dietary fibre is necessary to study the interaction of this biopolymer with nutrients. Yogurt with fortified chitosan and different types of plants fibres like wheat, bamboo, apple, psyllium and inulin was used as a food model. The availabilities of glucose and calcium in this model were studied by an in vitro gastrointestinal tract simulation. Results showed that the different fibres decreased both glucose and calcium availabilities whereas the effect of chitosan was more pronounced. (17.7 ± 2.1% and 21.0 ± 2.5% depress respectively). This work demonstrated that the addition of chitosan to yogurts influences the availability of nutrients.     

A Zooarchaeological Test for Dietary Resource Depression at the End of the Classic Period in the Petexbatun,Guatemala

Zooarchaeological analyses of animal remains from the Petexbatun sites in the Guatemalan lowlands provide proxy evidence to test a hypothesis of dietary insufficiency during the Maya “collapse.” Ecological foraging theory and resource depression models are used to interpret animal use patterns before and after the disintegration of the Petexbatun polity at the end of the Late Classic period (around a.d. 800). Environmental failure models of the Maya “collapse” at the end of the Late Classic imply that a dietary insufficiency, and particularly a lack of animal resources, was associated with the political and social transitions of this period. However, the results of this zooarchaeological study do not support this hypothesis and point instead to very limited early reductions of only highest-ranked dietary species. The lack of evidence for specific resource depression associated directly with the period of political collapse does not support a model of environmental failure during political disintegration in the Petexbatun. Correlations are found between animal use patterns and the specifics of site size and periods of peak political activity, suggesting that small-scale resource depressions might have resulted at some sites during early periods of human population growth, site expansion, and increasing political activity.     

Food attraction and population growth of fungivorous nematodes with different fungi

Food attraction of the fungivorous nematodes Aphelenchus avenae and Aphelenchoides spp. to seven fungal species (Pyrenochaeta lycopersici, Botrytis cinerea, Rhizoctonia solani strains AG 3 and AG 2‐1, Verticillium dahliae, Pochonia bulbillosa, Mortierella hyalina and Trichoderma harzianum) was determined on agar plates by counting the number of test nematodes present on the mycelium of each fungus 24 h after inoculation. Population growth of A. avenae and Aphelenchoides spp. on five of the seven fungi included in the attraction test (P. lycopersici, R. solani strain AG 3, V. dahliae, P. bulbillosa and T. harzianum) was also determined on agar plates by counting nematode numbers every week during a 6‐week period. A. avenae and Aphelenchoides spp. were attracted to all the fungi tested. A. avenae was preferentially attracted to V. dahliae (P < 0.0001), and Aphelenchoides spp. did not show any preference except for low attraction to R. solani. A. avenae and Aphelenchoides spp. reproduced on all fungal species tested. After 6 weeks of incubation, the highest number of nematodes was found on P. lycopersici and P. bulbillosa, while the lowest number occurred on R. solani for A. avenae and on T. harzianum for Aphelenchoides spp. The suitability of a fungus as a host was not clearly related to the attraction to that fungus.     

Diet composition of the endangered giant water bug Lethocerus deyrolli (Hemiptera: Belostomatidae) in the rice fields of Japan: Which is the most important prey item among frogs,fish, and aquatic insects?

The food habits of the endangered giant water bug, Lethocerus deyrolli, were studied in the rice fields of Nose, in the north of Osaka Prefecture, Japan. Field observations revealed that frogs were the most important prey item. Frogs represented 86.4% and 78.6% in the diet of L. deyrolli in spring and summer, respectively. Among seven species of three families (Hylidae, Rhacophoridae, and Ranidae) exploited by L. deyrolli, the most important food item was adult Hyla japonica in spring and juvenile Rana nigromaculta in summer. Fish and aquatic arthropods were not considered important foods for L. deyrolli. The frog‐dependent food habits indicate that the recovery and conservation of frogs should be prioritized to protect L. deyrolli from extinction.     

Epigean and subterranean ichthyofauna from the São Domingos karst area, Upper Tocantins River basin, Central Brazil

In a survey of epigean and cave streams in the São Domingos karst area, 38 species were present in the stream reaches, including 10 characiforms, 19 siluriforms, seven gymnotiforms and two perciforms. One species of Astyanax and the new armoured catfish species Parotocinclus were the most common epigean fishes in São Domingos. The most conspicuous non-troglomorphic cave fishes were Hoplerythrinus unitaeniatus , Astyanax sp., Brycon sp. and two species of Imparfinis , with I. hollandi being the most common fish in most caves. São Domingos karst area has the most diverse and abundant Brazilian cavefish fauna, not only in terms of troglobitic species but also in general fish richness, with 22 non-troglomorphic species recorded in caves in addition to five troglobitic ones. Most fishes examined for stomach contents had at least partially full stomachs. The studied fishes were carnivorous, feeding primarily on aquatic insects. Fishes with developed gonads recorded in caves were I. hollandi , Rhamdia quelen , Pseudocetopsis plumbeus , Hoplerythrinus unitaeniatus and Cichlasoma araguaiensis , indicating a potential for reproduction in the subterranean habitat.     

Quality Control and Assurance: crucial for the sustainability of the applied phycology industry

The chemical and nutritional properties of microalgae are well known, which has led to an ever expanding industry for foods and dietary supplements both in terms of quantity and products. Little has been done to regulate or control quality and assurance in the applied phycology industry and it is known that it varies considerably. Nutritional aspects of produced biomass and consumption as dietary supplements have become issues of concern, especially since the industry is lucrative and fast growing. Various claims are made regarding dietary and food supplements that include health, nutrition, structure and functioning, many often unsubstantiated. Although quality is a subjective term many organisations are involved in testing, controlling and determining criteria. Today quality is more than just standards where it is an "integrated quality management approach" involving amongst others "hazard analyses and critical control points" (HACCP) practices. Microalgae are not recognised as a food or food supplement and they are also not categorised under herbals or botanicals, but as "other supplements". Produced microalgal biomass is subject to contamination from the entire range of contaminants and pathogens. Contamination of products by algal toxins in mixed culture populations also occurs. The industry has largely regulated itself, but there is considerable scope for improvement. There is a need for support and dissemination of information in the industry.     

Dietary protein reduction in sheep and goats: different effects on <Emphasis Type="SmallCaps">l</Emphasis>-alanine and <Emphasis Type="SmallCaps">l</Emphasis>-leucine transport across the brush-border membrane of jejunal enterocytes

It was the aim of this study to examine the potential regulatory effects of a long-term low dietary protein supply on the transport capacity of the jejunal brush-border membrane for amino acids. For this purpose, we used the neutral amino acids L-alanine (representative for nonessential amino acids) and L-leucine (representative for essential amino acids) as model substances. Ten sheep lambs, 8 weeks of age and 19-27 kg body weight, were allotted to two dietary regimes with either adequate or reduced protein supply which was achieved by 17.9% and 9.7% of crude protein in the concentrated feed, respectively. The feeding periods were 4-6 weeks in length. Similarly, eight goat kids of 5-7 weeks of age and 8-14 kg body weight were allotted to either adequate (crude protein 20.1%, feeding period 9-12 weeks) or reduced protein supply (10.1%, feeding period 17-18 weeks). Dietary protein reduction in lambs caused a significant body weight loss of 0.6 +/- 0.7 kg, whereas the body weight in control animals increased by 1.9 +/- 0.7 kg (P<0.05). Plasma urea concentrations decreased significantly by 60% (low protein 2.3 +/- 0.1 versus control 5.7 +/- 0.2 mmol l(-1), P<0.001). In kids, reduction of dietary protein intake led to significant decreases of the daily weight gain by 48% from 181 +/- 8 g to 94 +/- 3 g (P<0.001) and daily dry matter intake by 27% from 568 +/- 13 g to 417 +/- 6 g (P<0.01). Respective urea concentrations in plasma were reduced by 77% from 5.2 +/- 0.4 to 1.2 +/- 0.2 mmol l(-1) (P<0.01). Kinetic analyses of the initial rates of alanine uptake into isolated jejunal brush-border membrane vesicles from sheep and goats as affected by low dietary protein supply yielded that the apparent Km was neither significantly different between the species nor significantly affected by the feeding regime thus ranging between 0.12 and 0.16 mmol.l(-1). Reduction of dietary protein, however, resulted in significantly decreased Vmax values of the transport system by 25-30%, irrespective of the species. Kinetic analyses of the initial rates of leucine uptake into jejunal brush-border membrane vesicles from sheep and goats yielded that leucine uptake was mediated by Na+-dependent as well as Na+-independent processes. Similar to alanine, apparent Km values of leucine uptake were neither different between the species nor affected due to low dietary protein and ranged between 0.08 and 0.15 mmol l(-1). In contrast to the alanine transport mechanism, dietary protein reduction resulted in increased Vmax values of Na+-dependent leucine transport by 53% in sheep and 230% in goats. Similarly, Na+-independent leucine uptake was stimulated by 85% and 200% in sheep and in goats, respectively. This study shows adaptation of amino acid absorption at the brush-border membrane level of jejunal enterocytes of small ruminants due to dietary protein reduction. Whereas the transport capacity for the nonessential amino acid alanine was reduced due to low dietary protein, the transport capacity for the essential amino acid leucine was markedly stimulated. From this, the involvement of rather different feedback mechanisms in adaptation of intestinal amino acid transport mechanisms has to be discussed.