Dynamic effects of dietary protein restriction on body weights, food consumption, and protein preference in C57BL/6J and Fgf21-KO mice.

Single-case experimental designs (SCEDs) are rarely used in behavioral neuroscience despite their potential benefits. The current study used a SCED to evaluate the effects of dietary protein restriction in C57BL/6J and Fgf21-knockout (KO) mice on body weight, food consumption, and protein preference and changes in those outcome measures were quantified using multilevel linear models. In C57BL/6J mice, rate of weight gain was lower and food consumption and protein preference higher during periods of low (4% kcal) protein diet feeding compared to periods of normal (18% kcal) protein diet feeding. In Fgf21-KO mice, who do not produce the liver-derived hormone FGF21, rate of weight gain and protein preference were not substantially affected by diet although food consumption was slightly higher during periods of low protein diet than periods of normal protein diet. These results demonstrate that protein restriction dynamically regulates physiological and behavioral responses at the individual mouse level and that FGF21 is necessary for those responses. Further, the current results demonstrate how a SCED can be used in behavioral neuroscience research, which entails both scientific and practical benefits.

Characterization and survey in cattle of a rumen Pyrimadobacter sp. which degrades the plant toxin fluoroacetate.

Among the natural halogenic compounds, the plant toxin fluoroacetate (FA) causes livestock fatalities in southern hemisphere countries. Here, we report on the isolation of a rumen bacterium, strain C12-8 that degrades FA under anaerobic conditions. 16S rRNA gene sequence analysis showed this bacterium belonged to the Pyramidobacter genus within the Synergistetes phylum and was 98% similar to Pyramidobacter piscolens W5455 isolated from the human oral cavity. Transmission electron microscopy showed the cell envelope to be unusual, with only one membrane and no obvious external wall. Growth and FA degradation were enhanced by peptide-rich protein hydrolysates but not carbohydrates. End products of metabolism were mainly acetate, propionate/isovalerate and isobutyrate. Strain C12-8 preferentially used peptide-bound amino acids rather than free amino acids. Glycine, serine, threonine, leucine, histidine and isoleucine were utilized as free and peptide-bound amino acids, but there was minimal utilization of alanine, proline, methionine, aspartic acid, lysine and arginine in either form. A survey of several cattle properties in northern Australia showed that strain C12-8 and other FA degrading bacteria affiliated with Cloacibacillus porcorum strain MFA1 were endemic to cattle in the northern beef herd and may help to reduce toxicity.

Nanoparticle-mediated in vitro delivery of E4orf1 to preadipocytes is a clinically relevant delivery system to improve glucose uptake.

OBJECTIVE: Impaired glycemic control is a common comorbidity of obesity. E4orf1(E4), an adenovirus-derived protein, reduces the activity of insulin receptor substrate (IRS), yet activates Akt and promotes the membrane translocation of GLUT4, resulting in better glycemic control in mice. To develop a clinically suitable delivery system, here we constructed and tested liposome nanoparticles (NP), to deliver E4 to preadipocytes. METHODS: Glutathione-S-transferase (GST)-tagged E4 was encapsulated in Rhodamine-phosphatidylethanolamine (PE)-tagged soy-phosphatidylcholine-NP. The NP were characterized. Preadipocytes were treated with free E4, E4 containing NP (E4 NP) or E4-free NP (void NP). RESULTS: For void and E4 NP, the average size was ~150 and 130 nm, PDI was ~0.25 and 0.27, and Zeta potential was -23 and -25, respectively. The average encapsulation efficiency (EE) was ~50%. Cells treated with E4 showed maximum GST expression and Rhodamine signals at 24 h. The presence of E4 in cells was confirmed at 24, 48, and 72 h. At 72 h after exposure, E4 NP significantly decreased pTyr-IRS, yet increased pAkt protein abundance, membrane translocation of GLUT4, and glucose uptake, compared with cells treated with void NP. Free E4 (without NP) had no effect. CONCLUSIONS: NP-mediated delivery of E4 promotes glucose uptake in preadipocytes. The next step is to test the efficacy of this clinically compatible delivery approach in vivo.

Fluoroacetate in plants - a review of its distribution, toxicity to livestock and microbial detoxification.

Fluoroacetate producing plants grow worldwide and it is believed they produce this toxic compound as a defence mechanism against grazing by herbivores. Ingestion by livestock often results in fatal poisonings, which causes significant economic problems to commercial farmers in many countries such as Australia, Brazil and South Africa. Several approaches have been adopted to protect livestock from the toxicity with limited success including fencing, toxic plant eradication and agents that bind the toxin. Genetically modified bacteria capable of degrading fluoroacetate have been able to protect ruminants from fluoroacetate toxicity under experimental conditions but concerns over the release of these microbes into the environment have prevented the application of this technology. Recently, a native bacterium from an Australian bovine rumen was isolated which can degrade fluoroacetate. This bacterium, strain MFA1, which belongs to the Synergistetes phylum degrades fluoroacetate to fluoride ions and acetate. The discovery and isolation of this bacterium provides a new opportunity to detoxify fluoroacetate in the rumen. This review focuses on fluoroacetate toxicity in ruminant livestock, the mechanism of fluoroacetate toxicity, tolerance of some animals to fluoroaceate, previous attempts to mitigate toxicity, aerobic and anaerobic microbial degradation of fluoroacetate, and future directions to overcome fluoroacetate toxicity.