Almost being there: video communication with young children

Background

Video communication is increasingly used to connect people around the world. This includes connecting young children with their parents and other relatives during times of separation. An important issue is the extent to which video communication with children can approximate a physical presence such that familial relationships can be truly maintained by this means.

Methodology/Principal Findings

The current study employed an adaptation of the Separation and Reunion Paradigm with children (17 months to 5 years) to investigate the potential for video communication with a parent to afford a sense of proximity and security to children. The protocol involved a free-play session with the parent, followed by two separation-reunion episodes. During one of the separation episodes the parent was ‘virtually available’ to the child via a video link. Our results revealed three important differences. First, children left alone played longer in a strange room when their parent was virtually available to them compared to when the children were left alone with neither physical nor video contact with their parent. Second, younger participants sought physical contact with their parent less at the end of the video separation episode compared to when they were left entirely alone. Finally, the comparison between free play with video and free play with parent, revealed that the children exhibit a similar level of interactivity with their parent by video as they did in person.

Conclusions/Significance

For young children a video connection can have many of the same effects as a physical presence. This is a significant finding as it is the first such empirical demonstration and indicates considerable promise in video communication as a tool to maintain family relationships when physical presence is not possible.     

Phosphite stimulated histological responses of Eucalyptus marginata to infection by Phytophthora cinnamomi

Phosphite is used to protect plants from the soil borne pathogen, Phytophthora cinnamomi. Although phosphite stimulates resistance to P. cinnamomi, this is the first histological study of its effect on Eucalyptus marginata, an economically important forest tree in Western Australia. Clonal lines of E. marginata, considered resistant and susceptible to P. cinnamomi, were underbark inoculated with P. cinnamomi. 4 days later, they were treated with 0, 2.5, 5 or 10 g L⁻¹ phosphite. Transverse hand sections were stained for suberin and lignin, and histological responses to infection were examined. Defence responses were stimulated at all phosphite concentrations in both clonal lines, and the genotypic difference in lesion length was eliminated within 8 days of treatment. In the resistant line, suberin production was stimulated while in the susceptible line both lignin and suberin were stimulated. By 2 days after treatment, phosphite stimulated a faster rate of suberin production in the resistant line than the susceptible line, but by 4 days after treatment, there was no difference in the increase between the lines. Damage caused by P. cinnamomi was found to extend furthest in the cortex and outer phloem in transverse sections in both genotypes. In the presence of P. cinnamomi, phosphite stimulated mitosis as part of the defence response, with meristematic activity involved in the compartmentalisation of damaged tissue (formation of periderm) and closure of healthy tissue (callus). Phytotoxicity had a detrimental effect in healthy tissues and this was more apparent in the resistant line, where it did not provide the best protection from lesion extension and plant mortality, suggesting phytotoxicity could disrupt defence responses. Phosphite increases the capacity of susceptible and resistant E. marginata clonal lines to wall-off and contain P. cinnamomi colonisation through lignin and suberin deposition, and increased meristematic activity.     

A metapopulation model of tuberculosis transmission with a case study from high to low burden areas

Tuberculosis (TB) is a growing problem worldwide, especially with the emergence and high prevalence of multidrug-resistant strains. We develop a metapopulation model for TB spread, which is particularly suited to investigating transmission between areas of high and low prevalence. A case study of cross-border transmission in the Torres Strait region of Australia and Papua New Guinea (PNG) is considered and a sensitivity analysis is conducted. We find that only 6 of the 50 parameters analysed are important to the cumulative number of clinically active TB patients in the entire region. Of these, only the detection rate in PNG is found to be an important intervention parameter. We therefore give insight into the extent the area with the high burden of TB (PNG in the case study) is dominating the TB dynamics of the entire region. Furthermore, the sensitivity analysis results give insight into the data that most important to collect and refine, which is found to be data relating to the PNG parameters.     

Synthesis of human amyloid restricted to liver results in an Alzheimer disease–like neurodegenerative phenotype

Several lines of study suggest that peripheral metabolism of amyloid beta (Aß) is associated with risk for Alzheimer disease (AD). In blood, greater than 90% of Aß is complexed as an apolipoprotein, raising the possibility of a lipoprotein-mediated axis for AD risk. In this study, we report that genetic modification of C57BL/6J mice engineered to synthesise human Aß only in liver (hepatocyte-specific human amyloid (HSHA) strain) has marked neurodegeneration concomitant with capillary dysfunction, parenchymal extravasation of lipoprotein-Aß, and neurovascular inflammation. Moreover, the HSHA mice showed impaired performance in the passive avoidance test, suggesting impairment in hippocampal-dependent learning. Transmission electron microscopy shows marked neurovascular disruption in HSHA mice. This study provides causal evidence of a lipoprotein-Aß /capillary axis for onset and progression of a neurodegenerative process.

It has been suggested that peripheral metabolism of amyloid-beta is associated with risk for Alzheimer’s disease. This study reveals that the expression of human amyloid exclusively in the liver induces Alzheimer’s disease-like pathologies in mice, potentially indicating a completely novel pathway of Alzheimer’s disease aetiology and therapies.     

GLP-1 and related peptides cause concentration-dependent relaxation of rat aorta through a pathway involving KATP and cAMP

Increasing evidence from both clinical and experimental studies indicates that the insulin-releasing hormone, glucagon-like peptide-1 (GLP-1) may exert additional protective/reparative effects on the cardiovascular system. The aim of this study was to examine vasorelaxant effects of GLP-1(7-36)amide, three structurally-related peptides and a non-peptide GLP-1 agonist in rat aorta. Interestingly, all GLP-1 compounds, including the established GLP-1 receptor antagonist, exendin (9-39) caused concentration-dependent relaxation. Mechanistic studies employing hyperpolarising concentrations of potassium or glybenclamide revealed that these relaxant effects are mediated via specific activation of ATP-sensitive potassium channels. Further experiments using a specific membrane-permeable cyclic AMP (cAMP) antagonist, and demonstration of increased cAMP production in response to GLP-1 illustrated the critical importance of this pathway. These data significantly extend previous observations suggesting that GLP-1 may modulate vascular function, and indicate that this effect may be mediated by the GLP-1 receptor. However, further studies are required in order to establish whether GLP-1 related agents may confer additional cardiovascular benefits to diabetic patients.     

Use of a Cry1Ac-Resistant Line of <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> (Lepidoptera: Noctuidae) to Detect Novel Insecticidal Toxin Genes in <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

This paper describes a screening strategy incorporating resistant insect lines for discovery of new Bacillus thuringiensis toxins against a background of known genes that would normally mask the activity of additional genes and the application of that strategy. A line of Helicoverpa armigera with resistance to Cry1Ac (line ISOC) was used to screen Cry1Ac-expressing strains of B. thuringiensis for additional toxins with activity against H. armigera. Using this approach, a number of Cry1Ac-producing strains with significant toxicity toward Cry1Ac-resistant H. armigera were identified. When the insecticidal protein complement of one of these strains, C81, was examined in detail, a novel cry2 gene (cry2Af1) was detected.     

Direct assessment of mineral phosphorus availability to tropical crops using 32P labelled compounds

The availability to plants of phosphorus (P) derived from sparingly soluble iron and aluminium phosphates was directly assessed with ³²P labelled compounds in two glasshouse trials.In the first experiment, the comparative availability of all mineral phosphate (P) compounds to maize increased with time (14 to 42 days post emergence) and plant total P uptake, but P source did not affect the growth or total plant uptake of P. The comparative availability of the amorphous AlPO₄ (Al-P), crystalline AlPO₄ (variscite), amorphous FePO₄ (Fe-P), and crystalline FePO₄ (strengite) compared to KH₂PO₄ (=100) was 53.1, 3.4, 38.9, and 1.9%, respectively. In the second experiment, the availability of Fe-P, strengite, and KH₂PO₄ to several topical crop species was examined. There was no difference between maize, sorghum, mungbean, cowpea or soybean in their ability to utilise Fe-P or KH₂PO₄, although maize utilised strengite more than the other species. The major difference between these species in their ability to acquire P appears to be a difference in ability to locate soluble soil P rather than differences in their ability to access different pools of soil P.The advantages of using neutron irradiation to directly measure P absorption from mineral P compounds over traditional methodologies is discussed.     

The primary structure of the human pancreatic secretory trypsin inhibitor: Amino acid sequence of the reduced S-aminoethylated protein

The amino acid sequence of human pancreatic secretory trypsin inhibitor [Pubols, M. H., Bartelt, D. C., and Greene, L. J. (1974) J. Biol. Chem., 249, 2235–2242] was determined by a combination of selective trypsin and chymotrypsin hydrolysis reactions on the S-2-aminoethylcysteinyl inhibitor and conventional methods (subtractive Edman degradation and exopeptidase hydrolysis) for sequence determination of small peptides. The peptides were ordered on the basis of the identification of the amino- and carboxyterminal residues of the products at each stage of the degradation procedure. The sequence determination was carried out on a mixture of chromatographic forms present in both tissue and pancreatic juice which are identical in amino acid composition, aminoterminal residues, molecular weight, and specific activity, but differ only in asparagine content and susceptibility to enzymatic hydrolysis. The amino acid sequence of the human inhibitor corresponding to chromatographic form A₃ has been shown to be NH₂

.     

Cutting edge: regulation of CD8+ T cell effector population size

Naive CD8(+) T cells are activated on encounter with Ag presented on dendritic cells and proliferate rapidly. To investigate the regulation of naive CD8(+) T cells proliferation, we adoptively transferred TCR-transgenic CD8(+) T cells into intact mice together with Ag-pulsed dendritic cells. Regardless of the number of cells initially transferred, the expansion of activated Ag-specific CD8(+) T cells was limited to a ceiling of effector cells. This limit was reached from a wide range of T cell doses, including a physiological number of precursor cells, and was not altered by changing the amount of Ag or APCs. The total Ag-specific response was composed of similar numbers of host and donor transgenic cells regardless of donor cell input, suggesting that these populations were independently regulated. Regulation of the transgenic donor cell population was TCR specific. We hypothesize that a clone-specific regulatory mechanism controls the extent of CD8(+) T cell responses to Ag.     

A regulatory domain in the C-terminal extension of the yeast glycerol channel Fps1p

The Saccharomyces cerevisiae gene FPS1 encodes an aquaglyceroporin of the major intrinsic protein (MIP) family. The main function of Fps1p seems to be the efflux of glycerol in the adaptation of the yeast cell to lower external osmolarity. Fps1p is an atypical member of the family, because the protein is much larger (669 amino acids) than most MIPs due to long hydrophilic extensions in both termini. We have shown previously that a short domain in the N-terminal extension of the protein is required for restricting glycerol transport through the channel (Tamás, M. J., Karlgren, S., Bill, R. M., Hedfalk, K., Allegri, L., Ferreira, M., Thevelein, J. M., Rydstr?m, J., Mullins, J. G. L., and Hohmann, S. (2003) J. Biol. Chem. 278, 6337-6345). Deletion of the N-terminal domain results in an unregulated channel, loss of glycerol, and osmosensitivity. In this work we have investigated the role of the Fps1p C terminus (139 amino acids). A set of eight truncations has been constructed and tested in vivo in a yeast fps1Delta strain. We have performed growth tests, membrane localization following cell fractionation, and glycerol accumulation measurements as well as an investigation of the osmotic stress response. Our results show that the C-terminal extension is also involved in restricting transport through Fps1p. We have identified a sequence of 12 amino acids, residues 535-546, close to the sixth transmembrane domain. This element seems to be important for controlling Fps1p function. Similar to the N-terminal domain, the C-terminal domain is amphiphilic and has a potential to dip into the membrane.