Microbial Geochemical Calcium Cycle

The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO₂ from the primitive atmosphere. Most calcium deposits were formed in the Precambrian, when the prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g. cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rocks, predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is recorded by stromatolites, which are the most common organo–sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO₂ does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the soda continent, which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca²⁺. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial communities, which were the precursors of stromatolites.     

Metabolic and Weight Loss Effects of Long‐Term Dietary Intervention in Obese Patients: Four‐Year Results

Objective: To investigate the contribution of meal and snack replacements for long‐term weight maintenance and risk factor reduction in obese patients. Research Methods and Procedures: Prospective, randomized, two‐arm, parallel intervention for 12 weeks followed by a prospective single‐arm 4‐year trial in a University Hospital clinic. One hundred patients, >18 years old and with a body mass index > 25 and ≤ 40 kg/m², were prescribed a 1200 to 1500 kcal/d control diet (Group A) or an isoenergetic diet, including two meal and snack replacements (vitamin‐ and mineral‐fortified shakes, soups, and bars) and one meal high in fruits and vegetables (Group B). Following a 3 months of weight loss, all patients were prescribed the same energy‐restricted diet (1200 to 1500 kcal) with one meal and one snack replacement for an additional 4 years. Results: All 100 patients were evaluated at 12 weeks. Mean percentage weight loss was 1.5 ± 0.4% and 7.8 ± 0.5% (mean ± SEM) for Groups A and B, respectively. At 12 weeks systolic blood pressure, plasma triacylglycerol, glucose, and insulin concentrations were significantly reduced in Group B, whereas no changes occurred in Group A. After 4 years, 75% of the patients were evaluated. Total mean weight loss was 3.2 ± 0.8% for Group A and 8.4 ± 0.8% (mean ± SEM) for Group B. Both groups showed significant improvement in blood glucose and insulin (p < 0.001), but only Group B showed significant improvement in triacylglycerol and systolic blood pressure compared to baseline values (p < 0.001). Discussion: Providing a structured meal plan via vitamin‐ and mineral‐fortified liquid meal replacements is a safe and effective dietary strategy for obese patients. Long‐term maintenance of weight loss with meal replacements can improve certain biomarkers of disease risk.     

Influence of source and micronization of soya bean meal on growth performance,nutrient digestibility and ileal mucosal morphology of Iberian piglets

The effects of inclusion in the diet of different sources of soya bean meal (SBM) on growth performance, total tract apparent digestibility (TTAD) and apparent ileal digestibility (AID) of major dietary components and mucosal ileum morphology were studied in Iberian pigs weaned at 30 days of age. From 30 to 51 days of age (phase I), there was a control diet based on regular soya bean meal (R-SBM; 44% CP) of Argentina (ARG) origin and five extra diets in which a high-protein soya bean meal (HP-SBM; 49% CP) of the USA or ARG origin, either ground (990 μm) or micronized (60 μm), or a soya protein concentrate (SPC; 65% CP) substituted the R-SBM. From 51 to 61 days of age (phase II), all pigs were fed a common commercial diet in mash form. The following pre-planned orthogonal contrasts were conducted: (1) R-SBM v. all the other diets, (2) SPC v. all the HP-SBM diets, (3) micronized HP-SBM v. ground HP-SBM, (4) HP-SBM of ARG origin v. HP-SBM of US origin and (5) interaction between source and the degree of grinding of the HP-SBM. Dietary treatment did not affect growth performance of the pigs at any age but from 30 to 51 days of age, post weaning diarrhoea (PWD) was higher (P<0.001) and the TTAD and AID of all nutrients were lower for pigs fed the R-SBM diet than for pigs fed the HP-SBM or the SPC diets. However, no differences between the HP-SBM and the SPC containing diets were detected for any trait. The TTAD of organic matter (P=0.07) and gross energy (GE) (P=0.05) tended to be higher for the micronized HP-SBM than for the ground HP-SBM and that of GE was higher (P<0.05) for US meal than for the ARG meal. Pigs fed R-SBM had lower villus height (P<0.01) than pigs fed HP-SBM or SPC but no differences in ileal mucosal morphology were detected between SPC and HP-SBM containing diets. It is concluded that feeding the HP-SBM or SPC-reduced PWD and improved nutrient digestibility and ileal morphology as compared with feeding the R-SBM, but had no effect on pig performance. The inclusion in the diet of added value soya products (micronized SBM or SPC) in substitution of the R-SBM increased the TTAD of all nutrients and reduced PWD but had no advantage in terms of growth performance over the use of ground HP-SBM.     

Effect of dietary replacement of fish meal protein with crawfish shell meal (Procambarus clarkii) on the growth performance,digestive enzyme activity and anti-oxidative capacity of Oujiang color common carp (Cyprinus carpio var. color)

This study was designed to evaluate the effects of dietary crawfish shell meal (CSM) on the growth performance, digestive enzyme activity and anti-oxidative capacity of Oujiang color common carp. 180 juvenile fish (initial weight 3.0 ± 0.5 g) were assigned to the control group and the CSM25 group (fed with 25% substitution of fish meal by CSM) for 8 weeks. Results showed that significant improvement in the weight gain rate (WGR) in CSM25 group than the control (p < .05), whereas no significant change in feed conversion ratio, specific growth rate and feeding intake between the groups (p > .05). Also, no significant difference was obsevered between the groups in terms of serum biochemical index and muscle composition (p > .05). And liver superoxide dismutase, catalase, glutathione peroxidase (GPx), lysozyme (LYZ) and protease activities in CSM25 group were significantly higher (p < .05). Moreover, histological analysis indicated that width of mucosa and thickness of muscular coat in mid-intestine were significantly changed (p < .05). In conclusion, dietary supplement with CSM25 induced high oxidative stress, promote protease activities and had no negative effects on the growth performance of Oujiang color common carp. Hence, CSM may be a viable alternative protein source to reduce the demand for fish meal.     

Polyphasic characterization of benthic cyanobacterial diversity from biofilms of the Guadarrama river (Spain): morphological,molecular, and ecological approaches1

The occurrence and environmental factors responsible for the distribution of benthic cyanobacteria in running waters remain largely unexplored in comparison with those of other aquatic ecosystems. In this study, combined data of ecological characteristics, molecular analysis (based on 16S rRNA gene), and direct microscopic inspection of environmental samples were analyzed in parallel with the morphological characterization of the isolated strains to investigate benthic cyanobacterial diversity in the Guadarrama river (Spain). A total of 17 species were identified that belonged to the genera Aphanocapsa, Pleurocapsa, Chroococcus, Chamaesiphon, Cyanobium, Pseudan‐abaena, Leptolyngbya, Phormidium, Nostoc, and Tolypothrix. Phenotypic features were associated with the results of 16S rRNA gene sequencing, complementing existing morphological and genetic databases. A decrease in the cyanobacterial diversity was observed along a pollution gradient in the river. Water quality differed among the sampling sites, and variation in nutrient content was the principal difference among locations. These characteristics were closely associated with an upstream‐downstream eutrophic gradient. Canonical correspondence analysis distinguished three groups of species with respect to the eutrophication gradient. The first group (Tolypothrix cf. tenuis, Nostoc punctiforme, Nostoc piscinale, Chamaesiphon investiens, Chroococcus minor, Leptolyngbya nostocorum, and Leptolyngbya tenuis) was characteristic of waters with low levels of nutrients. The second group (Cyanobium sp., Chamaesiphon polymorphus, Leptolyngbya boryana, Phormidium autumnale, Phormidium sp., and Aphanocapsa cf. rivularis) was characteristic of polluted waters, its members appearing mainly in great abundance under eutrophic‐hypertrophic conditions. The third group of species (Pseudanabaena catenata, Aphanocapsa muscicola, and Nostoc carneum) was present at upstream and downstream sites.     

Use of Brassicaceous seed meals to improve seedling emergence of tomato and pepper in Pythium ultimum infested soils

Growth room studies were conducted to determine the impact of Brassicaceae seed meals on the emergence of tomato and pepper seedlings in Pythium ultimum infested soils. Pasteurised Burch sandy loam soils were amended with intact and denatured seed meal of rape seed and mustard. Brassica juncea or Brassica napus intact seed meal increased the tomato and pepper seedling emergence. Interestingly, B. napus amended soils resulted in the same seedling emergence with B. juncea regardless of their relatively lower glucosinolate content compared to mustard-based seed meals. Seedling emergence in soils amended with intact Sinapis alba seed meal was significantly the lowest for both tomato and pepper seedlings. In contrast, seedling emergence was higher in soils amended with denatured than intact S. alba seed meals suggesting some glucosinolate-related inhibitory effect on seedling emergence of both crops. Glycine max seed meal amendment improved the seedling emergence better than the control but to a lower-level when compared to glucosinolate containing seed meals. This finding suggests that even though improvement of seedling emergence of tomato and pepper in P. ultimum infested soils can be achieved using Brassicaceae seed meals, it cannot be entirely attributed to glucosinolate-related processes. These studies demonstrate that intact B. napus and B. juncea seed meals can be used to improve tomato and pepper seedling emergence in P. ultimum infested soils.     

The role of the blood meal in egg-laying periodicity and fecundity in Triatoma infestans

The number of eggs produced by Triatoma infestans is determined by the amount of blood ingested; the formation of one egg requires 16 mg blood. An exogenous supply of juvenile hormone, provided by the implantation of extra corpora aliata, increases egg production per unit of blood ingested. The corpus allatum is therefore implicated in the relationship between nutrition and fecundity. The rhythm of egg production is regulated by the nutritional state of the adult female: when the females are fed at frequent intervals, egg production becomes regular and continuous. This calls into question previous interpretations of egg-laying rhythms in the Triatominae as cyclic.     

Eating meals before wheel-running exercise attenuate high fat diet-driven obesity in mice under two meals per day schedule

Mice that exercise after meals gain less body weight and visceral fat compared to those that exercised before meals under a one meal/exercise time per day schedule. Humans generally eat two or three meals per day, and rarely have only one meal. To extend our previous observations, we examined here whether a “two meals, two exercise sessions per day” schedule was optimal in terms of maintaining a healthy body weight. In this experiment, “morning” refers to the beginning of the active phase (the “morning” for nocturnal animals). We found that 2-h feeding before 2-h exercise in the morning and evening (F-Ex/F-Ex) resulted in greater attenuation of high fat diet (HFD)-induced weight gain compared to other combinations of feeding and exercise under two daily meals and two daily exercise periods. There were no significant differences in total food intake and total wheel counts, but feeding before exercise in the morning groups (F-Ex/F-Ex and F-Ex/Ex-F) increased the morning wheel counts. These results suggest that habitual exercise after feeding in the morning and evening is more effective for preventing HFD-induced weight gain. We also determined whether there were any correlations between food intake, wheel rotation, visceral fat volume and skeletal muscle volumes. We found positive associations between gastrocnemius muscle volumes and morning wheel counts, as well as negative associations between morning food intake volumes/body weight and morning wheel counts. These results suggest that morning exercise-induced increase of muscle volume may refer to anti-obesity. Evening exercise is negatively associated with fat volume increases, suggesting that this practice may counteract fat deposition. Our multifactorial analysis revealed that morning food intake helps to increase exercise, and that evening exercise reduced fat volumes. Thus, exercise in the morning or evening is important for preventing the onset of obesity.