The use of a T-maze to measure cognitive–motor function in cats (Felis catus)

Few tests have been developed to evaluate the cognitive and motor capabilities of domestic cats, despite the suitability of cats for specific studies of neuroanatomy, infectious diseases, development, aging, and behavior. The present study evaluated a T-maze apparatus as a sensitive and reliable measure of cognition and motor function in cats. Eighteen purpose-bred, specific pathogen-free, male, neutered domestic short-haired cats (Felis catus), 1-2 years of age, were trained and tested to a T-maze protocol using food rewards. The test protocol consisted of positional discrimination training (left arm or right arm) to reach a predetermined criterion, followed by 2 discrimination reversal tests. The 2 reversal tests documented the ability of the subjects to respond to a new reward location by switching arms of the T-maze. Data were collected on side preference, number of correct responses, and latency of the responses by the subjects. Aided by a customized computer program (CanCog Technologies), data were recorded electronically as each cat progressed from the start box to the reward arm. The protocol facilitated rapid training to a high and consistent level of performance during the discrimination training. This learning was associated with a decrease in the latency to traverse the maze to a mean of 4.80 ± 0.87 seconds, indicating strong motivation and consistent performance. When the rewarded side was reversed in the test phase, the cats required more trials to reach the criterion, as expected, but again showed reliable learning. The latency to the reward in the first session of reversal increased 86% from the first to the last trial, indicating that it may provide a useful index of cognitive processing. Latencies subsequently decreased as the new reversal paradigm was learned. This paradigm provides a relatively rapid and reliable test of cognitive–motor performance that can be used in various settings for the evaluation of feline cognitive and motor function.     

Life after the regime: market instability with the fall of the US food regime

The US food regime maintained some degree of stability in terms of prices and production levels for commodities in the world economy. This food regime, resting on supply management policy, began to falter in the early 1970s. In the late-1980s and 1990s, notable changes occurred in the world economy regarding agriculture as the food regime became more market-oriented. The end of the twentieth century saw the breakdown of many institutions, organizations, and international agreements that had tried to stabilize prices and production from 1945 to 1975. This paper examines this period of change (roughly 1960–2010) and explores the effects on five commodities: cocoa, coffee, corn, soybeans, and wheat. These commodities offer important points of comparison. First, while cocoa, coffee, and wheat were regulated by international organizations and agreements, corn and soybeans were not. Second, the US dominated the international corn and soybean markets, but the cocoa, coffee, and wheat markets were much more competitive. And third, corn, soybeans, and wheat were commodities largely produced in the core of the world economy, while cocoa and coffee were produced in the periphery. Thus, comparing the effect of the fall of the US food regime on these commodities reveals the importance of previous regulation, the level of market competition, and geographic origin in the world economy.     

酶制剂在家禽日粮中的应用

<正>国际家禽科学论坛于2008年1月21-22日在美国亚特兰大世界议会中心举办。本次论坛由美国南部家禽科学会(southern poultry science society)、南部禽病协商会(southern conference on avain disease)和美国家禽与蛋品协会联合发起。     

Sequencing of Culex quinquefasciatus establishes a platform for mosquito comparative genomics

Culex quinquefasciatus (the southern house mosquito) is an important mosquito vector of viruses such as West Nile virus and St. Louis encephalitis virus, as well as of nematodes that cause lymphatic filariasis. C. quinquefasciatus is one species within the Culex pipiens species complex and can be found throughout tropical and temperate climates of the world. The ability of C. quinquefasciatus to take blood meals from birds, livestock, and humans contributes to its ability to vector pathogens between species. Here, we describe the genomic sequence of C. quinquefasciatus: Its repertoire of 18,883 protein-coding genes is 22% larger than that of Aedes aegypti and 52% larger than that of Anopheles gambiae with multiple gene-family expansions, including olfactory and gustatory receptors, salivary gland genes, and genes associated with xenobiotic detoxification.     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

The effect of potassium deficiency on chemical, biochemical and physical factors commonly associated with blackspot development in potato tubers

Blackspot bruise is a physiological disorder of potato tubers resulting from mechanical damage to tissues during handling. This study examined the effect of potassium nutrition on biochemical and physical changes normally associated with blackspot bruise in potato tubers. Four potato (Solanum tuberosum L.) genotypes (TXA 763-5 [very resistant], Ranger Russet [very susceptible], Russet Burbank [susceptible], and Lemhi Russet [very susceptible]) differing in susceptibility to blackspot bruise were grown at three potassium nutrition levels (100%, 10% and 0% of the potassium in full strength Hoagland’s solution). Tubers from the three treatments were tested for their chemical, biochemical and physical characteristics commonly related to blackspot bruise susceptibility. The potential to develop malanin pigments was measured as total oxidative potential (optical density, OD₄₇₅) of clarified tuber homogenates. Tuber tissue extracts were assayed for polyphenol oxidase (PPO) activity with catechol, measured as increase in OD₄₁₀ over time. Specific gravity of tubers was determined with a brine solution series. Physical property measurements were made by impacting cores of tuber tissue in a specially designed instrumented pendulum. Shock wave speed, Young’s modulus, failure stress, and failure strain were all measured dynamically during impact. Tubers produced under both the 10% and 0% potassium regimens had almost 2x the free tyrosine of control tubers. The 0% potassium tubers had significantly higher PPO activity than the control. Both of these factors likely contributed to the significantly higher total oxidative potential that was observed in tubers from both the 10% and 0% potassium treatments. Tubers from both the 0% and 10% potassium treatments had a significantly lower Young’s modulus (a measure of stiffness), significantly lower failure stress and the shock wave of impact propagated through both of them significantly slower. Although the cultivars were significantly different in their susceptibility to black pigment development, they all responded similarly to the treatment with regards to the variables measured. The TXA-763-5 clone was much more susceptible to developing black pigments in these tests than expected. The other three cultivars performed as they do in commerce.     

Chemistry and Bioactivity of the Deep-Water Antarctic Octocoral Alcyonium sp.

Chemical investigation of an Antarctic deep-water octocoral has led to the isolation of four new compounds, including three illudalane sesquiterpenoids (1–3) related to the alcyopterosins, a highly oxidized steroid, alcyosterone (5), and five known alcyopterosins (4, 6–9). The structures were established by extensive 1D and 2D NMR analyses, while 9 was verified by XRD. Alcyopterosins are unusual for their nitrate ester functionalization and have been characterized with cytotoxicity related to their DNA binding properties. Alcyopterosins V (3) and E (4) demonstrated single-digit micromolar activity against Clostridium difficile, an intestinal bacterium capable of causing severe diarrhea that is increasingly associated with drug resistance. Alcyosterone (5) and several alcyopterosins were similarly potent against the protist Leishmania donovani, the causative agent of leishmaniasis, a disfiguring disease that can be fatal if not treated. While the alcyopterosin family of sesquiterpenes is known for mild cytotoxicity, the observed activity against C. difficile and L. donovani is selective for the infectious agents.