Actinomycin D and cycloheximide actions on activity of some intestinal enzymes of adult hamster

Actinomycin D, at a dose of 0.25 micrograms/g body wt, produced slight increases in intestinal enzymatic activity on hamsters. At a high dose (1.5 micrograms/g body wt), actinomycin D produced inhibition of lactase activity, whereas maltase, sucrase and alkaline phosphatase activity decreased in males and increased in females. Cycloheximide (1.5 micrograms/g body wt), produced no changes in enzymatic activity. In the male and female hamster, the different actions of the antibiotic can be explained by the variations in the cortisol release produced by stress.     

Phytoplankton Growth and Microzooplankton Grazing in the Subtropical Northeast Atlantic

Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2–5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11–1.60 d⁻¹), especially in the case of the large fraction. Grazing rates were also high (0.15–1.29 d⁻¹), suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O₂ supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres.     

The impact of interventions in the global land and agri‐food sectors on Nature’s Contributions to People and the UN Sustainable Development Goals

Interlocked challenges of climate change, biodiversity loss, and land degradation require transformative interventions in the land management and food production sectors to reduce carbon emissions, strengthen adaptive capacity, and increase food security. However, deciding which interventions to pursue and understanding their relative co‐benefits with and trade‐offs against different social and environmental goals have been difficult without comparisons across a range of possible actions. This study examined 40 different options, implemented through land management, value chains, or risk management, for their relative impacts across 18 Nature's Contributions to People (NCPs) and the 17 Sustainable Development Goals (SDGs). We find that a relatively small number of interventions show positive synergies with both SDGs and NCPs with no significant adverse trade‐offs; these include improved cropland management, improved grazing land management, improved livestock management, agroforestry, integrated water management, increased soil organic carbon content, reduced soil erosion, salinization, and compaction, fire management, reduced landslides and hazards, reduced pollution, reduced post‐harvest losses, improved energy use in food systems, and disaster risk management. Several interventions show potentially significant negative impacts on both SDGs and NCPs; these include bioenergy and bioenergy with carbon capture and storage, afforestation, and some risk sharing measures, like commercial crop insurance. Our results demonstrate that a better understanding of co‐benefits and trade‐offs of different policy approaches can help decision‐makers choose the more effective, or at the very minimum, more benign interventions for implementation.     

Current methods for molecular typing of Campylobacter species

Campylobacter remains one of the most common bacterial causes of gastroenteritis worldwide. Tracking sources of this organism is challenging due to the large numbers of human cases, and the prevalence of this organism throughout the environment due to growth in a wide range of animal species. Many molecular subtyping methods have been developed to characterize Campylobacter species, but only a few are commonly used in molecular epidemiology studies. This review examines the applicability of these methods, as well as the role that emerging whole genome sequencing technologies will play in tracking sources of Campylobacter spp. infection.     

Effects of dietary L-arginine supplementation on serum lipids and intestinal enzyme activities in diabetic rats

We investigated whether dietary supplementation with L-arginine, the endogenous precursor of nitric oxide, might affect serum lipid levels and activities of intestinal mucosa enzymes in animals, in which diabetes was induced by administration of streptozotocin. Control and diabetic rats were fed diets with or without 2% L-arginine supplementation for 4 weeks. Diabetic rats had significantly higher concentrations of serum triglycerides and LDL-cholesterol than control rats. These alterations were partially reduced by L-arginine supplementation. Experimental diabetes did not influence the lactase and leucine aminopeptidase activity in the intestine, but the activity of alkaline phosphatase was increased. Furthermore, activities of maltase and sucrase in the intestinal mucosa were elevated in streptozotocin-induced diabetic rats and were restored to control levels after dietary L-arginine supplementation. On the basis of the present experimental evidence, dietary L-arginine supplementation appears to affect the metabolism of lipoproteins and might alleviate some gastrointestinal dysfunctions, commonly seen in diabetes mellitus.     

Some Like It Fat: Comparative Ultrastructure of the Embryo in Two Demosponges of the Genus Mycale (Order Poecilosclerida) from Antarctica and the Caribbean

During embryogenesis, organisms with lecithotrophic indirect development usually accumulate large quantities of energetic reserves in the form of yolk that are necessary for larval survival. Since all sponges have lecithotrophic development, yolk formation is an ineludible step of their embryogenesis. Sponge yolk platelets have a wide range of morphological forms, from entirely lipid or protein platelets to a combined platelet showing both lipids and proteins and even glycogen. So far, there are no comparative studies on the nature and content of yolk in congeneric species of sponges inhabiting contrasting environments, which could have putative effects on the larval adaptation to environmental conditions. Here, we have taken advantage of the worldwide distribution of the sponge genus Mycale, in order to compare the embryogenesis and yolk formation in two species inhabiting contrasting latitudinal areas: M. acerata from Antarctic waters and M. laevis from the Caribbean. We have compared their brooded embryos and larvae using scanning and transmission electron microscopy, and calculated their energetic signatures based on the nature of their yolk. While the general morphological feature of embryos and larvae of both species were very similar, the main difference resided in the yolk nature. The Antarctic species, M. acerata, showed exclusively lipid yolk, whereas the Caribbean species, M. laevis, showed combined platelets of lipids and proteins and less frequently protein yolk platelets. The larvae of M. acerata were estimated to possess a two-fold energetic signature compared to that of M. laevis, which may have important ecological implications for their survival and for maintaining large population densities in the cold waters of the Southern Ocean.     

Continuous removal of endocrine disruptors by versatile peroxidase using a two‐stage system

The oxidant Mn³⁺‐malonate, generated by the ligninolytic enzyme versatile peroxidase in a two‐stage system, was used for the continuous removal of endocrine disrupting compounds (EDCs) from synthetic and real wastewaters. One plasticizer (bisphenol‐A), one bactericide (triclosan) and three estrogenic compounds (estrone, 17β‐estradiol, and 17α‐ethinylestradiol) were removed from wastewater at degradation rates in the range of 28–58 µg/L·min, with low enzyme inactivation. First, the optimization of three main parameters affecting the generation of Mn³⁺‐malonate (hydraulic retention time as well as Na‐malonate and H₂O₂ feeding rates) was conducted following a response surface methodology (RSM). Under optimal conditions, the degradation of the EDCs was proven at high (1.3–8.8 mg/L) and environmental (1.2–6.1 µg/L) concentrations. Finally, when the two‐stage system was compared with a conventional enzymatic membrane reactor (EMR) using the same enzyme, a 14‐fold increase of the removal efficiency was observed. At the same time, operational problems found during EDCs removal in the EMR system (e.g., clogging of the membrane and enzyme inactivation) were avoided by physically separating the stages of complex formation and pollutant oxidation, allowing the system to be operated for a longer period (～8 h). This study demonstrates the feasibility of the two‐stage enzymatic system for removing EDCs both at high and environmental concentrations. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:908–916, 2015     

Epidemiology, Relative Invasive Ability, Molecular Characterization, and Competitive Performance of Campylobacter jejuni Strains in the Chicken Gut

One hundred forty-one Campylobacter jejuni isolates from humans with diarrhea and 100 isolates from retailed poultry meat were differentiated by flaA typing. The bacteria were isolated in a specific geographical area (Dunedin) in New Zealand over a common time period. Twenty nine flaA types were detected, one of which (flaA restriction fragment length polymorphism type 15 [flaA-15]) predominated among isolates from humans (~30% of isolates). This strain was of low prevalence (5% of isolates) among poultry isolates. flaA-15 strains were five to six times more invasive of HEp2 cells in an in vitro assay than a flaA type (flaA-3) that was commonly encountered on poultry meat (23% of isolates) but was seldom associated with human illness (5%). Competitive-exclusion experiments with chickens, utilizing real-time quantitative PCR to measure the population sizes of specific strains representing flaA-15 (T1016) and flaA-3 (Pstau) in digesta, were carried out. These experiments showed that T1016 always outcompeted Pstau in the chicken intestine. Genomic comparisons of T1016 and Pstau were made using DNA microarrays representing the genome of C. jejuni NCTC 11168. These comparisons revealed differences between the strains in the gene content of the Cj1417c-to-Cj1442c region of the genome, which is associated with the formation of capsular polysaccharide. The strains differed in Penner type (T1016, O42; Pstau, O53). It was concluded that poultry meat was at least one source of human infection with C. jejuni, that some Campylobacter strains detected in poultry meat are of higher virulence for humans than others, and that bacterial attributes affecting strain virulence and commensal colonization ability may be linked.     

Inflammation and matrix remodeling during repair of ventilator-induced lung injury

High-pressure ventilation triggers different inflammatory and matrix remodeling responses within the lung. Although some of them may cause injury, the involvement of these mediators in repair is largely unknown. To identify mechanisms of repair after ventilator-induced lung injury (VILI), mice were randomly assigned to baseline conditions (no ventilation), injury [90 min of high-pressure ventilation without positive end-expiratory pressure (PEEP)], repair (injury followed by 4 h of low-pressure ventilation with PEEP), and ventilated controls (low-pressure ventilation with PEEP for 90 and 330 min). Histological injury and lung permeability increased during injury, but were partially reverted in the repair group. This was accompanied by a proinflammatory response, together with increases in TNF-α and IFN-γ, which returned to baseline during repair, and a decrease in IL-10. However, macrophage inflammatory protein-2 (MIP-2) and matrix metalloproteinases (MMP)-2 and -9 increased after injury and persisted in being elevated during repair. Mortality in the repair phase was 50%. Survivors showed increased cell proliferation, lower levels of collagen, and higher levels of MIP-2 and MMP-2. Pan-MMP or specific MMP-2 inhibition (but not MIP-2, TNF-α, or IL-4 inhibition) delayed epithelial repair in an in vitro wound model using murine or human alveolar cells cultured in the presence of bronchoalveolar lavage fluid from mice during the repair phase or from patients with acute respiratory distress syndrome, respectively. Similarly, MMP inhibition with doxycycline impaired lung repair after VILI in vivo. In conclusion, VILI can be reverted by normalizing ventilation pressures. An adequate inflammatory response and extracellular matrix remodeling are essential for recovery. MMP-2 could play a key role in epithelial repair after VILI and acute respiratory distress syndrome.