HKT1;5-like cation transporters linked to Na+ exclusion loci in wheat, Nax2 and Kna1

Bread wheat (Triticum aestivum) has a greater ability to exclude Na⁺ from its leaves and is more salt tolerant than durum wheat (Triticum turgidum L. subsp. durum [Desf.]). A novel durum wheat, Line 149, was found to contain a major gene for Na⁺ exclusion, Nax2, which removes Na⁺ from the xylem in the roots and leads to a high K⁺-to-Na⁺ ratio in the leaves. Nax2 was mapped to the distal region on chromosome 5AL based on linkage to microsatellite markers. The Nax2 locus on 5AL coincides with the locus for a putative Na⁺ transporter, HKT1;5 (HKT8). The Nax2 region on 5AL is homoeologous to the region on chromosome 4DL containing the major Na⁺ exclusion locus in bread wheat, Kna1. A gene member of the HKT1;5 family colocates to the deletion bin containing Kna1 on chromosome 4DL. This work provides evidence that Nax2 and Kna1 are strongly associated with HKT1;5 genes.     

Lip reconstruction

Lip reconstruction remains challenging. Accurate analysis of the defect and a thorough understanding of the anatomy and options for reconstruction will maintain the functional and aesthetic quality of this sensitive area.     

Evaluation of a 'bias-free' measure of awareness

The derivation of a reliable, subjective measure of awareness that is not contaminated by observers' response bias is a problem that has long occupied researchers. Kunimoto et al. (2001) proposed a measure of awareness (a') which apparently meets this criterion: a' is derived from confidence ratings and is based on the intuition that confidence should reflect awareness. The aim of this paper is to explore the validity of this measure. Some calculations suggested that, contrary to Kunimoto et al.'s intention, a' can vary as a result of changes in response bias affecting the relative proportions of high- and low-confidence responses. This was not evident in the results of Kunimoto et al.'s original experiments because their method may have artificially 'clamped' observers' response bias close to zero. A predicted consequence of allowing response bias to vary freely is that it can result in a' varying from negative, through zero, to positive values, for a given value of discriminability (d'). We tested whether such variations are likely to occur in practice by employing Kunimoto et al.'s paradigm with various modifications, notably the removal of constraints upon the proportions of low- and high-confidence responses, in a visual discrimination task. As predicted, a' varied with response bias in all participants. Similar results were found when a' was calculated from pre-existing data obtained from a patient with blindsight: a' varied through a range of positive results without approaching zero, which is inconsistent with his well-documented lack of awareness. A second experiment showed how response bias could be manipulated to yield elevated values of a'. On the basis of these findings we conclude that Kunimoto's measure is not as impervious to response bias as was originally assumed.     

Subtle defects in pre-TCR signaling in the absence of the Tec kinase Itk

alphabeta T cell development in the thymus is dependent on signaling through the TCR. The first of these signals is mediated by the pre-TCR, which is responsible for promoting pre-T cell proliferation and the differentiation of CD4(-)8(-)3(-) (DN) thymocytes into CD4(+)8(+)3(+) (DP) cells. In many cases, T cell signaling proteins known to be essential for TCR signaling in mature T cells are also required for pre-TCR signaling in DN thymocytes. Therefore, it came as a surprise to discover that mice lacking the Tec kinases Itk and Rlk, enzymes required for efficient activation of phospholipase C-gamma1 in mature T cells, showed no obvious defects in pre-TCR-dependent selection events in the thymus. In this report, we demonstrate that DN thymocytes lacking Itk, or Itk and Rlk, are impaired in their ability to generate normal numbers of DP thymocytes, especially when placed in direct competition with WT DN thymocytes. We also show that Itk is required for maximal pre-TCR signaling in DN thymocytes. These data demonstrate that the Tec kinases Itk and Rlk are involved in, but are not essential for, pre-TCR signaling in the thymus, suggesting that there is an alternative mechanism for activating phospholipase C-gamma1 in DN thymocytes that is not operating in DP thymocytes and mature T cells.     

Emerging functions of the calpain superfamily of cysteine proteases in neuroendocrine secretory pathways

The first calpain protease was discovered over 40 years ago now, yet despite the vast amount of literature that has subsequently emerged detailing their involvement in the pathophysiology of a variety of human diseases, it is only in the last decade that calpain-mediated actions along the secretory pathway have begun to emerge. However, the number of secretory pathway substrates identified and their diversity of function continues to grow. This review summarizes our current knowledge of calpain-mediated mechanisms of action that are pertinent to synaptic vesicle assembly and budding, cytoskeletal organization, endosomal recycling, and exocytotic membrane fusion.     

Parental preference for sons and daughters in a Western industrial setting: evidence and implications

This paper considers whether sex composition of existing children in Australian families is an important factor in parity progression. Using census data from 1981, 1986, 1991, 1996 and 2001, women are linked with their co-resident children, allowing investigation of family sex composition and its changing impact over time on the propensity to have another child. The study finds that parents are much more likely to have a third and fourth birth if existing children are all of the same sex, indicating a strong preference for children of both sexes. This increased propensity has added around three per cent to the fertility of recent cohorts. The paper concludes with a discussion of the potential impact of sex-selection technologies on fertility. The authors argue that future widespread use of reliable sex-selection technologies might act to increase fertility in the short term, but would lead to a long-term reduction in fertility.     

Evaluation of Potential Factors Predisposing Livestock to Predation by Jaguars

ABSTRACT Depredation of livestock by large carnivores is an important but poorly understood source of human-carnivore conflict. We examined patterns of livestock depredation by jaguars (Panthera onca) and pumas (Puma concolor) on a ranch-wildlife reserve in western Brazil to assess factors contributing to prey mortality. We predicted jaguars would kill a greater proportion of calves than yearling and adult cattle and that proximity to suitable habitat would increase mortality risk. We further speculated that exposure to predation risk would promote livestock grouping and increased movement distance. We recorded 169 cattle mortality incidents during 2003–2004, of which 19% were due to predation by jaguars and pumas. This level of mortality represented 0.2–0.3% of the total livestock holdings on the ranch. Jaguars caused most (69%) cattle predation events, and survival in allotments was lower for calves than for other age classes. Forest proximity was the only variable we found to explain patterns of livestock mortality, with predation risk increasing as distance to forest cover declined. Due to low predation risk, cattle movement patterns and grouping behavior did not vary relative to level of spatial overlap with radiocollared jaguars. The overall effect of predation on cattle was low and livestock likely constituted an alternative prey for large cats in our study area. However, selection of calves over other age cohorts and higher predation risk among cattle in proximity to forest cover is suggestive of selection of substandard individuals. Cattle ranchers in the Pantanal region may reduce cattle mortality rates by concentrating on losses due to nonpredation causes that could be more easily controlled.     

Hearing Range of White-Tailed Deer as Determined by Auditory Brainstem Response

Abstract: Basic knowledge of white-tailed deer (Odocoileus virginianus) hearing can improve understanding of deer behavior and may assist in the development of effective deterrent strategies. Using auditory brainstem response testing, we determined that white-tailed deer hear within the range of frequencies we tested, between 0.25–30 kilohertz (kHz), with best sensitivity between 4–8 kHz. The upper limit of human hearing lies at about 20 kHz, whereas we demonstrated that white-tailed deer detected frequencies to at least 30 kHz. This difference suggests that research on the use of ultrasonic (frequencies >20 kHz) auditory deterrents is justified as a possible means of reducing deer—human conflicts.