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Biomedical subjects

Julie M Jones

Publications and source records attributed to Julie M Jones.

10 recordsLinked to original sources
PubMed2005

Mutation of Vps54 causes motor neuron disease and defective spermiogenesis in the wobbler mouse.

Vacuolar-vesicular protein sorting (Vps) factors are involved in vesicular trafficking in eukaryotic cells. We identified the missense mutation L967Q in Vps54 in the wobbler mouse, an animal model of amyotrophic lateral sclerosis, and also characterized a lethal allele, Vps54(beta-geo). Motoneuron survival and spermiogenesis are severely compromised in the wobbler mouse, indicating that Vps54 has an essential role in these processes.

Amino Acid Sequence↗
PubMed2004

Atmospheric science: early peak in Antarctic oscillation index.

The principal extratropical atmospheric circulation mode in the Southern Hemisphere, the Antarctic oscillation (or Southern Hemisphere annular mode), represents fluctuations in the strength of the circumpolar vortex and has shown a trend towards a positive index in austral summer in recent decades, which has been linked to stratospheric ozone depletion and to increased atmospheric greenhouse-gas concentrations. Here we reconstruct the austral summer (December-January) Antarctic oscillation index from sea-level pressure measurements over the twentieth century and find that large positive values, and positive trends of a similar magnitude to those of past decades, also occurred around 1960, and that strong negative trends occurred afterwards. This positive Antarctic oscillation index and large positive trend during a period before ozone-depleting chemicals were released into the atmosphere and before marked anthropogenic warming, together with the later negative trend, indicate that natural forcing factors or internal mechanisms in the climate system must also strongly influence the state of the Antarctic oscillation.

Journal Article↗
PubMed2004

Reconstructing past climate from noisy data.

Empirical reconstructions of the Northern Hemisphere (NH) temperature in the past millennium based on multiproxy records depict small-amplitude variations followed by a clear warming trend in the past two centuries. We use a coupled atmosphere-ocean model simulation of the past 1000 years as a surrogate climate to test the skill of these methods, particularly at multidecadal and centennial time scales. Idealized proxy records are represented by simulated grid-point temperature, degraded with statistical noise. The centennial variability of the NH temperature is underestimated by the regression-based methods applied here, suggesting that past variations may have been at least a factor of 2 larger than indicated by empirical reconstructions.

Journal Article↗
PubMed2003

Loss of Omi mitochondrial protease activity causes the neuromuscular disorder of mnd2 mutant mice.

The mouse mutant mnd2 (motor neuron degeneration 2) exhibits muscle wasting, neurodegeneration, involution of the spleen and thymus, and death by 40 days of age. Degeneration of striatal neurons, with astrogliosis and microglia activation, begins at around 3 weeks of age, and other neurons are affected at later stages. Here we have identified the mnd2 mutation as the missense mutation Ser276Cys in the protease domain of the nuclear-encoded mitochondrial serine protease Omi (also known as HtrA2 or Prss25). Protease activity of Omi is greatly reduced in tissues of mnd2 mice but is restored in mice rescued by a bacterial artificial chromosome transgene containing the wild-type Omi gene. Deletion of the PDZ domain partially restores protease activity to the inactive recombinant Omi protein carrying the Ser276Cys mutation, suggesting that the mutation impairs substrate access or binding to the active site pocket. Loss of Omi protease activity increases the susceptibility of mitochondria to induction of the permeability transition, and increases the sensitivity of mouse embryonic fibroblasts to stress-induced cell death. The neurodegeneration and juvenile lethality in mnd2 mice result from this defect in mitochondrial Omi protease.

Amino Acid Sequence↗
PubMed2003

Whole grains health claims in the USA and other efforts to increase whole-grain consumption.

In response to the 1990 Nutrition Labeling and Education Act, the Food and Drug Administration approved seven health claims that addressed the relationship between broad food categories and risk of certain chronic diseases. These claims are based on scientific consensus that includes epidemiological, animal and clinical research. The Food and Drug Administration also established a process to petition for new health claims that address substance-disease relationships supported by adequate scientific and specific regulatory requirements. The whole grain-cancer and heart disease authoritative statement health claim approved in July 1999 followed a completely different process mandated by the Food and Drug Administration Modernization Act of 1997. It is based on an authoritative statement made by a government body that represents scientific consensus and is supported by other scientific agencies and organizations. The scientific basis for the claim published in Diet and Health reflects a comprehensive and deliberative review of epidemiological, animal and human studies by the National Academy of Sciences Committee on Diet and Health. Health claims used on whole grain products can attract the attention of health-conscious consumers and are important tools in communicating health messages. However, the US public consumes substantially fewer whole-grain servings than recommended by US dietary guidance. Reasons given by consumers for not purchasing wholegrain foods include colour, price, softness, texture, moisture content and taste. Developing tastier value-added wholegrain foods along with simple coordinated messages from industry, the scientific community, public health experts and government will help consumers identify, purchase and consume more wholegrain products.

Dietary Fiber↗
PubMed2002

Molecular and pathological effects of a modifier gene on deficiency of the sodium channel Scn8a (Na(v)1.6).

Scn8a encodes an abundant, widely distributed voltage-gated sodium channel found throughout the central and peripheral nervous systems. Mice with different mutant alleles of Scn8a provide models of the movement disorders ataxia, dystonia, tremor and progressive paralysis. We previously reported that the phenotype of the hypomorphic allele of Scn8a, medJ, is dependent upon an unlinked modifier locus, Scnm1. Strain C57BL/6J carries a sensitive allele of the modifier locus that results in juvenile lethality. We now provide evidence that the modifier acts on the splicing efficiency of the mutant splice donor site. Mutant mice display either 90% or 95% reduction in the proportion of correctly spliced mRNA, depending on modifier genotype. The abundance of the channel protein, Na(v)1.6, is also reduced by an order of magnitude in medJ mice, resulting in delayed maturation of nodes of Ranvier, slowed nerve conduction velocity, reduced muscle mass and reduction of brain metabolic activity. medJ mice provide a model for the physiological effects of sodium channel deficiency and the molecular mechanism of bigenic disease.

Alleles↗
PubMed2002

The importance of promoting a whole grain foods message.

Despite mention in the Dietary Guidelines for Healthy Americans and in Healthy People 2010, the lack of a coordinated campaign promoting whole grain foods and their health benefits may be contributing to low consumption. Fiber consumption in the U.S. likewise falls below recommended levels, in part, as a result of suboptimal intake of whole grain foods. Research findings suggest that whole grain is related to reduced disease risk, and that whole grain foods have relevant biological activity in humans. This necessitates a call to action to help Americans increase whole grain consumption as a strategy for health. The establishment of a whole grain coalition could promote increased consumption by developing consumer messages: partnering with health professionals: advocating whole grains to government agencies; seeking funding for scientific research and market research; and educating consumers, as well as health professionals, food manufacturers and millers, about the value and benefit of whole grains.

Dietary Fiber↗