Cortical 5-HT2A receptor signaling modulates anxiety-like behaviors in mice

Serotonin [5-hydroxytryptamine (5-HT)] neurotransmission in the central nervous system modulates depression and anxiety-related behaviors in humans and rodents, but the responsible downstream receptors remain poorly understood. We demonstrate that global disruption of 5-HT2A receptor (5HT2AR) signaling in mice reduces inhibition in conflict anxiety paradigms without affecting fear-conditioned and depression-related behaviors. Selective restoration of 5HT2AR signaling to the cortex normalized conflict anxiety behaviors. These findings indicate a specific role for cortical 5HT2AR function in the modulation of conflict anxiety, consistent with models of cortical, "top-down" influences on risk assessment.     

Anaerobic biotransformation of organo-arsenical pesticides monomethylarsonic acid and dimethylarsinic acid

Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organo-arsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively.     

Why short‐term biochar application has no yield benefits: evidence from three field‐grown crops

This study determines the impact of biochar, as a supplement, on soil nutrient availability and yields for three crops within commercial management systems in a temperate environment. Central to the suggestion of biochar benefits is an increase in soil nutrient availability, and here, we test this idea by examining crop nutrient uptake, growth and yields of field‐grown spring barley, strawberry and potato. Biochar produced from Castanea sativa wood was incorporated into a sandy loam soil at 0, 20 and 50 t/ha as a supplement to standard crop management practice. Fertilizer was applied normally for each of the three crops. The biochar contained substantial concentrations of Ca, Mg, K, P, but only K occurred at high concentration in water‐soluble analysis. The large concentration of extractable K resulted in a significant increase of extractable K in soil. The increased availability of K in biochar‐treated soil, with the exception of spring barley grain and the leaves of strawberry during the second year, did not induce greater tissue concentrations. In general, biochar application rate had little influence on the tissue concentration of any nutrient, irrespective of crop or sampling date. There was, however, evidence of a biochar‐induced increase in tissue Mo and a decrease in Mn, in strawberry, which could be linked to soil alkalinization as could the reduction in extractable soil P. These experiments show a single rotational application of biochar to soil had no effect on the growth or harvest yield of any of these field‐grown crops. Heavy metal analysis revealed small concentrations in the biochar (i.e. <10 μg/g biochar), with the largest levels for Ni, V and Cu.     

Increased cartilage oligomeric matrix protein concentrations in equine digital flexor tendon sheath synovial fluid predicts intrathecal tendon damage

Objectives: To evaluate digital flexor tendon sheath (DFTS) synovial fluid cartilage oligomeric matrix protein (COMP) concentrations as a molecular marker for intrathecal pathology. Study Design: Case control study. Animals: Horses (n=46) with DFTS tenosynovitis; 23 fresh cadaver horses. Methods: DFTS synovial fluid samples were collected from clinical cases with noninfected DFTS tenosynovitis and from control DFTS. Clinical and surgical findings were recorded, and dissection of control limbs was performed to confirm the DFTS to be grossly normal. Synovial fluid COMP was quantified using a homologous competitive inhibition ELISA. Results: Abnormalities were identified tenoscopically: intrathecal tendon/ligament tearing was identified in 37 cases and 9 had other lesions. In control horses, synovial fluid COMP was higher in younger horses. Clinical cases with intrathecal tendon/ligament tearing had higher synovial fluid COMP than either clinical cases with other lesions, or controls. In horses ≥5 years old, the sensitivity and specificity of the assay was high for diagnosing intrathecal tendon/ligament tearing. Conclusions: COMP concentrations in DFTS synovial fluid were significantly greater than those in normal horses with noninfected tenosynovitis caused by intrathecal tendon/ligament tearing, but not by other lesions.     

A preliminary study on the effect of wounding on transforming growth factor-β1 and cartilage oligomeric matrix protein concentrations in the skin of horses

Objective: To evaluate whether wound type or site influence the production of cartilage oligomeric matrix protein (COMP) and transforming growth factor β1 (TGF‐β1), and determine if there is a correlation between TGF‐β1and COMP during healing. Study Design: Experimental. Animals: Standardbred horses (n=6), 4–8 years old. Methods: Six, standardized, full‐thickness skin wounds (open, straight, and elliptical) were surgically created on the neck (n=3) and metacarpus (3) on each horse. Wounds were randomly allocated to site and side. Tissue samples were collected before creating wounds and on days 7, 14, and 42. COMP concentration (μg/g dry weight of tissue) was determined using a standard competitive ELISA and TGF‐β1 (ng/g dry weight of tissue) was determined using a commercially available sandwich ELISA. Results: COMP concentrations were higher in intact skin on the neck compared with the metacarpus (P=.02). There was no difference in COMP and TGF‐β1 concentrations between the different wound types or sites during healing. There was no correlation between TGF‐β1 and COMP during healing. Conclusions: Within the limitations of the study design, production of COMP during healing of skin wounds does not appear to be influenced by wound type or anatomic site, nor does it appear to be correlated with TGF‐β1 concentrations.     

Novel gastric helicobacters and oral campylobacters are present in captive and wild cetaceans

The mammalian gastric and oral mucosa may be colonized by mixed Helicobacter and Campylobacter species, respectively, in individual animals. To better characterize the presence and distribution of Helicobacter and Campylobacter among marine mammals, we used PCR and 16S rDNA sequence analysis to examine gastric and oral samples from ten dolphins (Tursiops gephyreus), one killer whale (Orcinus orca), one false killer whale (Pseudorca crassidens), and three wild La Plata river dolphins (Pontoporia blainvillei). Helicobacter spp. DNA was widely distributed in gastric and oral samples from both captive and wild cetaceans. Phylogenetic analysis demonstrated two Helicobacter sequence clusters, one closely related to H. cetorum, a species isolated from dolphins and whales in North America. The second related cluster was to sequences obtained from dolphins in Australia and to gastric non-H. pylori helicobacters, and may represent a novel taxonomic group. Dental plaque sequences from four dolphins formed a third cluster within the Campylobacter genus that likely represents a novel species isolated from marine mammals. Identification of identical Helicobacter spp. DNA sequences from dental plaque, saliva and gastric fluids from the same hosts, suggests that the oral cavity may be involved in transmission. These results demonstrate that Helicobacter and Campylobacter species are commonly distributed in marine mammals, and identify taxonomic clusters that may represent novel species.     

Feeding Levels of the Southern Brown Shrimp Penaeus subtilis in Response to Food Dispersal

The development of efficient feed management strategies in shrimp farming involves the investigation of aspects related to time of feed distribution, feeding rates, feeding frequency, and feed dispersal methods. This work examined the feeding levels of Penaeus subtilis in response to food dispersal method under semi-intensive culture conditions. The study consisted of two treatments: 1) a uniform feed dispersal over the culture area, and 2) concentration of feed in 0.2-m² circular feeding trays. For each, three 105-m² rectangular enclosures were installed in a single shrimp grow-out pond and stocked with P. subtilis at a density of 14.29 postlarvae/m². Shrimp were fed daily at 0600, 0930 and 1430 h and sampled 30 min after feed distribution at 12-d intervals. After collection, shrimp weight was determined, their stomachs dissected and weighed. A total of 2,160 stomachs of P. subtilis were collected during a 89-d rearing cycle. Relative occurrence of artificial versus natural food in stomach contents was determined by stable carbon isotope mass spectrometry. Density of polychaetes in the substrate was monitored at each sampling period. After harvest, sediment samples were collected for physical and chemical analyses. In general, differences in shrimp growth between feeding methods were not significant. Final shrimp survival rates were between 69.0 ± 6.9% and 71.9 ± 3.7%. Stomach content weight of P. subtilis was significantly higher when feed was broadcast than for feed concentration. Average stomach content weight remained constant throughout the rearing cycle, although progressive increases in feed Occurrence were detected in P. subtilis diet. No periodicity in food intake along sampling periods could be related to increases in shrimp carapace length. Food intake was significantly lower at 0600 h than at 1430 h and at 0930 h, respectively. In both treatments, over half of the food contained in the stomach contents of shrimp was derived from artificial food. Sediment chemical analysis indicated statistically lower levels of sodium in the pond bottom of concentrated treatment. However, no short-term detrimental effects were detected on sediment chemical quality. Results indicated that feed broadcasting resulted in a greater access and a higher consumption of food among the cultured shrimp population, a lower number of empty stomachs, and a greater occurrence of artificial food in P. subtilis stomach contents.