Showing papers by "University of Adelaide published in 1997"
Book•
01 Jan 1997TL;DR: The Oxford University Press and the Institute of Physics have joined forces to create a major reference publication devoted to EC fundamentals, models, algorithms and applications, intended to become the standard reference resource for the evolutionary computation community.
Abstract: From the Publisher:
Many scientists and engineers now use the paradigms of evolutionary computation (genetic agorithms, evolution strategies, evolutionary programming, genetic programming, classifier systems, and combinations or hybrids thereof) to tackle problems that are either intractable or unrealistically time consuming to solve through traditional computational strategies Recently there have been vigorous initiatives to promote cross-fertilization between the EC paradigms, and also to combine these paradigms with other approaches such as neural networks to create hybrid systems with enhanced capabilities To address the need for speedy dissemination of new ideas in these fields, and also to assist in cross-disciplinary communications and understanding, Oxford University Press and the Institute of Physics have joined forces to create a major reference publication devoted to EC fundamentals, models, algorithms and applications This work is intended to become the standard reference resource for the evolutionary computation community The Handbook of Evolutionary Computation will be available in loose-leaf print form, as well as in an electronic version that combines both CD-ROM and on-line (World Wide Web) acess to its contents Regularly published supplements will be available on a subscription basis
2,461 citations
TL;DR: A greater understanding of how mycorrhizas function in complex natural systems is a prerequisite to managing them in agriculture, forestry, and restoration.
Abstract: A great diversity of plants and fungi engage in mycorrhizal associations. In natural habitats, and in an ecologically meaningful time span, these associations have evolved to improve the fitness of both plant and fungal symbionts. In systems managed by humans, mycorrhizal associations often improve plant productivity, but this is not always the case. Mycorrhizal fungi might be considered to be parasitic on plants when net cost of the symbiosis exceeds net benefits. Parasitism can be developmentally induced, environmentally induced, or possibly genotypically induced. Morphological, phenological, and physiological characteristics of the symbionts influence the functioning of mycorrhizas at an individual scale. Biotic and abiotic factors at the rhizosphere, community, and ecosystem scales further mediate mycorrhizal functioning. Despite the complexity of mycorrhizal associations, it might be possible to construct predictive models of mycorrhizal functioning. These models will need to incorporate variables and parameters that account for differences in plant responses to, and control of, mycorrhizal fungi, and differences in fungal effects on, and responses to, the plant. Developing and testing quantitative models of mycorrhizal functioning in the real world requires creative experimental manipulations and measurements. This work will be facilitated by recent advances in molecular and biochemical techniques. A greater understanding of how mycorrhizas function in complex natural systems is a prerequisite to managing them in agriculture, forestry, and restoration.
1,776 citations
TL;DR: The performance impairment caused by fatigue is compared with that due to alcohol intoxication, and it is shown that moderate levels of fatigue produce higher levels of impairment than the proscribed level of alcohol intoxication.
Abstract: Reduced opportunity for sleep and reduced sleep quality are frequently related to accidents involving shift-workers1,2,3 Poor-quality sleep and inadequate recovery leads to increased fatigue, decreased alertness and impaired performance in a variety of cognitive psychomotor tests4 However, the risks associated with fatigue are not well quantified Here we equate the performance impairment caused by fatigue with that due to alcohol intoxication, and show that moderate levels of fatigue produce higher levels of impairment than the proscribed level of alcohol intoxication
1,113 citations
TL;DR: In this paper, the authors examined the linkages between trust in a salesperson, trust in the store, and repeat purchase intention, and found that for those with an interpersonal relationship, trust and commitment to the salesperson are directly linked with purchase intention as well as indirectly through store attitude.
836 citations
TL;DR: It seems more than ever likely that blood-derived stem cells will replace marrow for many indications, according to recent data from the International Bone Marrow Transplant Registry (IBMTR).
725 citations
TL;DR: In the ocean, nitrogen-rich microorganisms produce and recycle most organic matter in the water column, from which degraded particles rain onto the underlying sea floor and the buried organic matter joins the geological cycle, surfacing again millions of years later as kerogen uplifted in continental rocks as discussed by the authors.
670 citations
TL;DR: It is concluded that when considering the physiology of the symbiosis and especially the issue of whether different fungus/host interfaces have specialized roles in transfer of inorganic nutrients and organic carbon between the partners, if there is no such specialization between hyphai coils and arbuscules, then the latter might not be necessary for the function of Paris-types.
Abstract: summary
This review describes diversity in the structure of (vesicular)-arbuscutar (VA) mycorrhizas, i.e. endomycorrhizas formed by Glomalean fungi. In particular, we consider the extent in the plant kingdom of the two classes first described by Gallaud (1905). These are: (1) the Arum-type, defined on the basis of an extensive intercellular phase of hyphai growth in the root cortex and development of terminal arbuscules on intracellular hyphai branches; (2) the Paris-type, defined by the absence of the intercellular phase and presence of extensive intracellular hyphai coils. Arbuscules are intercalary structures on the coils. However, there have been many reports that in Paris-types arbuscules are relatively few in numbers, small, or absent altogether.
A survey of the literature has revealed that Paris-types occur more frequently in the plant kingdom than Arum-types and predominate in ferns, gymnosperms and many wild angiosperms. The cultivated herbs that are the subject of much experimental work are mostly Arum-types. Although evidence is still limited, there are differences at the family level. In 41 angiosperm families there are records of only Poris-type VA mycorrhizas and in 30 families records of only Arum-types. Another 21 families have examples of both classes, or intermediates between them. Accordingly, we consider whether the original division into two classes is still useful. We conclude that it is when considering the physiology of the symbiosis and especially the issue of whether different fungus/host interfaces have specialized roles in transfer of inorganic nutrients and organic carbon between the partners, if there is no such specialization between hyphai coils and arbuscules, then the latter might not be necessary1 for the function of Paris-types. This would account for reports of the infrequency or absence of arbuscules in this class. The control exerted on structures by the genomes of host and fungus, and possible reasons (anatomical and physiological) for the existence of the VA mycorrhizal structures, are discussed. The presence or absence of extensive intercellular spaces and differences in the wall structure of cortical cells might be particularly important in determining which type of VA mycorrhiza is formed.
434 citations
TL;DR: The results firmly establish the use of salivary melatonin measurements for phase typing of the melatonin rhythm in humans.
Abstract: There are many situations in which it would be useful to know the phase state of the biological clock. It is recognized that measurement of melatonin levels can provide this information, but traditionally blood has been used for the analysis, and there are many problems in extending the measurements into the home or field situations. The aim of this study was to develop and validate a salivary melatonin radioimmunoassay and to compare results obtained against a plasma assay for determining the onset of melatonin secretion. The assay developed was sensitive (4.3 pM) and required only 200 microliters of sample. A rhythm in melatonin was detected in saliva, peaking at approximately 120 pM or 30% of the plasma levels. Using an objective criterion for determining the onset of secretion (mean +/- 2 standard deviations of three daytime samples), the time of onset was shown to exhibit low intraindividual variability (coefficient of variation = 1.5%-4.3%). The time of onset determined using saliva was significantly correlated with the plasma onset (r = .70, p < .05). The onsets determined were 22:30 h +/- 22 min for the saliva and 21:50 h +/- 16 min for plasma for 17 subjects. Similarly, the acrophases of the saliva and plasma melatonin rhythms were significantly correlated. Neither posture alone nor changes in posture affected the calculation of the onset of melatonin secretion using the saliva approach. Very high saliva flow rates induced by citric acid resulted in lower melatonin concentrations compared to the gentle chewing on parafin film. These results firmly establish the use of salivary melatonin measurements for phase typing of the melatonin rhythm in humans.
418 citations
TL;DR: Time-lapse video cinematography is shown to be an excellent tool for studying fertilization and early embryo development, and it was found that good quality embryos arose from oocytes that had more uniform timing from injection to pronuclear abuttal and tended to have a longer cytoplasmic wave.
Abstract: In this study, we have used time-lapse video cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally, and the fertilization rate and embryo quality were not significantly different from 487 sibling oocytes cultured in a conventional incubator. Normal fertilization followed a defined course of events, although the timing of these events varied markedly between oocytes. In 35 of the 38 fertilized oocytes (92%), there were circular waves of granulation within the ooplasm which had a periodicity of 20-53 min. The sperm head decondensed during this granulation phase. The second polar body was then extruded, and this was followed by the central formation of the male pronucleus. The female pronucleus formed in the cytoplasm adjacent to the second polar body at the same time as, or slightly after, the male pronucleus, and was subsequently drawn towards the male pronucleus until the two abutted. Both pronuclei then increased in size, the nucleoli moved around within the pronuclei and some nucleoli coalesced. During pronuclear growth, the organelles contracted from the cortex towards the centre of the oocyte, leaving a clear cortical zone. The oocyte decreased in diameter from 112 to 106 microm (P < 0.0001) during the course of the observation period. The female pronucleus was significantly smaller in diameter than the male pronucleus (24.1 and 22.4 microm respectively, P = 0.008) and contained fewer nucleoli (4.2 and 7.0 respectively, P < 0.0001). After time-lapse recording, oocytes were cultured for 48 h prior to embryo transfer or cryopreservation. Embryo quality was related to fertilization events and periodicity of the cytoplasmic wave, and it was found that good quality embryos arose from oocytes that had more uniform timing from injection to pronuclear abuttal and tended to have a longer cytoplasmic wave. In conclusion, we have shown that time-lapse video cinematography is an excellent tool for studying fertilization and early embryo development, and have demonstrated that human fertilization comprises numerous complex dynamic events.
398 citations
Journal Article•
TL;DR: It is proposed that changes at the level of chromatin structure lead to the expression of a protein that facilitates the pathway by which mitochondria activate caspase-3 and trigger apoptotic death of lymphoid and colorectal cancer cells.
Abstract: The induction of apoptosis of tumor cells by the colonic fermentation product butyrate is thought to be an important mechanism in protection against colorectal cancer. Because a major action of butyrate is to inhibit histone deacetylase (leading to chromatin relaxation and altered gene expression), butyrate may induce apoptosis by derepression of specific cell death genes. Here we show that butyrate and trichostatin A (a more selective inhibitor of histone deacetylase) induce the same program of apoptosis in Jurkat lymphoid and LIM 1215 colorectal cancer cell lines that is strictly dependent on new protein synthesis (within 10 h) and that leads to the conversion of the proenzyme form of caspase-3 to the catalytically active effector protease (within 16 h) and apoptotic death (within 24 h). Cells primed with a low concentration of butyrate that itself did not induce activation of caspase-3 or apoptosis were, nevertheless, rendered highly susceptible to induction of apoptosis by staurosporine (an agent that has recently been shown to act by causing mitochondrial release of cytochrome c). Synergy between butyrate and staurosporine was due to the presence of a factor in the cytosol of butyrate-primed cells which enhanced over 7-fold the activation of caspase-3 induced by the addition of cytochrome c and dATP to isolated cytosol. We propose that changes at the level of chromatin structure, induced by a physiological substance butyrate, lead to the expression of a protein that facilitates the pathway by which mitochondria activate caspase-3 and trigger apoptotic death of lymphoid and colorectal cancer cells.
388 citations
Journal Article•
TL;DR: Hypermethylation was observed in two of seven sporadic breast carcinomas but not in any normal tissues, consistent with an important role for epigenetic mechanisms in human cancer.
Abstract: Mutations of the BRCA1 gene in tumor DNA from patients with sporadic breast cancer have not yet been observed. Nevertheless, BRCA1 activity is markedly decreased in invasive breast tumors. Previous reports have shown that hypermethylation of the promoter region is an alternative mechanism to mutation for the inactivation of tumor suppressor genes. We examined the BRCA1 promoter region for hypermethylation by Southern blotting. Hypermethylation was observed in two of seven sporadic breast carcinomas but not in any normal tissues. The hypermethylation was not an artifact because a control region was unmethylated in the two tumors. Although not all tumors were hypermethylated, these observations are consistent with an important role for epigenetic mechanisms in human cancer.
TL;DR: Both heuristics and optimizing algorithms have important roles to play in conservation planning and the choice of method will depend on the size of data sets, the representation goal, the required time for analysis, and the importance of a guaranteed optimal solution.
TL;DR: Artificial neural networks are introduced and applied as a new, promising model type for modelling and prediction of algal blooms to indicate that artificial neural networks can fit the complexity and nonlinearity of ecological phenomena apparently to a high degree.
TL;DR: The dependence of the urinary hydroxyproline on the urinary calcium and sodium suggests that the bone resorption is a response to calcium losses rather than a primary event, and there is some doubt as to whether it can inhibit trabecular bone loss in women close to the menopause.
TL;DR: TNF-alpha has the unique ability to induce apoptosis in human neutrophils via a mechanism where TNFR75 facilitates the dominant TNFR55 death effect, and may be an important mechanism controlling neutrophil longevity and clearance in vivo.
TL;DR: In this article, a positive theory explaining pollution tax policy outcomes in a small open economy is developed, where the equilibrium tax rate depends on lobby group membership, the relative importance of lobbying activities, and the tax elasticity of pollution.
TL;DR: In this paper, the authors extended the concept by adding brand decision involvement and purchasing involvement to derive retail customer segments, and the clusters derived show strong differences across both purchase behaviour and response to marketing strategies.
TL;DR: The isolation, culture and toxicity characterisation of Cylindrospermopsis from a water bloom in a small lake in NSW, Australia is described and is suggestive of other toxic compounds in this isolate.
TL;DR: The case for accounting and management research from a grounded theory perspective, and advocates its informed and more frequent application, is discussed in this paper, where the authors discuss the intellectual foundations and key tenets of grounded theory in the context of researchers' theoretical assumptions and methodological characteristics.
Abstract: Restates the case for accounting and management research from a grounded theory perspective, and advocates its informed and more frequent application. Examines the intellectual foundations and key tenets of grounded theory in the context of researchers’ theoretical assumptions and methodological characteristics, discussed in relation to Laughlin’s (1995) classification schema. Pays particular attention to grounded theory assumptions and methods in relation to other interpretive paradigms such as symbolic interactionism, ethnomethodology and hermeneutics. Describes the basic principles and methods of grounded theory research, and presents potential applications to the accounting and management research arenas. Argues that rigorous grounded theory research can offer the accounting and management literatures unique understandings that provide additional perspectives to those already being offered by major schools of thought, and discusses implications of grounded theory for informing contemporary professional practice.
TL;DR: Simulated and real images have been tested in a variety of formats, and the results show that the symmetry can be determined using the Gaussian image.
Abstract: Symmetry detection is important in the area of computer vision. A 3D symmetry detection algorithm is presented in this paper. The symmetry detection problem is converted to the correlation of the Gaussian image. Once the Gaussian image of the object has been obtained, the algorithm is independent of the input format. The algorithm can handle different kinds of images or objects. Simulated and real images have been tested in a variety of formats, and the results show that the symmetry can be determined using the Gaussian image.
TL;DR: Control of sulfidogenesis and sulfide detoxification maybe important in the disease process of UC, although whether their roles is in an initiating or promoting capacity has yet to be determined.
Abstract: A role for colonic sulfide in the pathogenesis and treatment of ulcerative colitis (UC) has emerged based on biochemical, microbiological, nutritional, toxicological, epidemiological, and therapeutic evidence. Metabolism of isolated colonic epithelial cells has indicated that the bacterial short-chain fatty acid n-butyrate maintains the epithelial barrier and that sulfides can inhibit oxidation of n-butyrate analogous to that observed in active UC. Sulfur for fermentation in the colon is essential for n-butyrate formation and sulfidogenesis aids disposal of colonic hydrogen produced by bacteria. The numbers of sulfate-reducing bacteria and sulfidogenesis is greater in UC than control cases. Sulfide is mainly detoxified by methylation in colonic epithelial cells and circulating red blood cells. The enzyme activity of sulfide methylation is higher in red blood cells of UC patients than control cases. Patients with UC ingest more protein and thereby sulfur amino acids than control subjects. Removing foods rich in sulfur amino acids (milk, eggs, cheese) has proven therapeutic benefits in UC. 5-Amino salicylic acid reduces fermentative production of hydrogen sulfide by colonic bacteria, and aminoglycosides, which inhibit sulfate-reducing bacteria, are of therapeutic benefit in active UC. Methyl-donating agents are a category of drugs of potential therapeutic use in UC. A correlation between sulfide production and mucosal immune responses in UC needs to be undertaken. Control of sulfidogenesis and sulfide detoxification may be important in the disease process of UC, although whether their roles is in an initiating or promoting capacity has yet to be determined.
TL;DR: Division of the SGVs during laparoscopic Nissen fundoplication did not improve any clinical or objective postoperative outcome.
Abstract: OBJECTIVE: To determine whether division of the short gastric vessels (SGVs) and full mobilization of the gastric fundus is necessary to reduce the incidence of postoperative dysphagia and other adverse sequelae of laparoscopic Nissen fundoplication. SUMMARY BACKGROUND DATA: Based on historical and uncontrolled studies, division of the SGVs has been advocated during laparoscopic Nissen fundoplication to improve postoperative clinical outcomes. However, this modification has not been evaluated in a large prospective randomized trial. METHODS: One hundred two patients with proven gastroesophageal reflux disease presenting for laparoscopic Nissen fundoplication were prospectively randomized to undergo fundoplication with (52 patients) or without (50 patients) division of the SGVs. Patients with esophageal motility disorders, patients requiring a concurrent abdominal procedure, and patients who had undergone previous antireflux surgery were excluded. Patients were blinded to the postoperative status of their SGVs. Clinical assessment was performed by a blinded independent investigator who used multiple standardized clinical grading systems to assess dysphagia, heartburn, and patient satisfaction 1, 3, and 6 months after surgery. Objective measurement of lower esophageal sphincter pressure, esophageal emptying time, and distal esophageal acid exposure and radiologic assessment of postoperative anatomy were also performed. RESULTS: Operating time was increased by 40 minutes (median 65 vs. 105) by vessel division. Perioperative outcomes and complications, postoperative dysphagia, relief of heartburn, and overall satisfaction were not improved by dividing the SGVs. Lower esophageal sphincter pressure, acid exposure, and esophageal emptying times were similar for the two groups. CONCLUSION: Division of the SGVs during laparoscopic Nissen fundoplication did not improve any clinical or objective postoperative outcome.
Journal Article•
TL;DR: The existence of a chemokine network in vivo involving at least four individual chemokines that regulates recruitment of the major peripheral blood granulocytes and mononuclear phagocytes to s.c. sites during acute inflammation is demonstrated.
Abstract: In this study, we have evaluated the role of specific chemotactic cytokines in leukocyte recruitment to s.c. tissue in response to TNF-alpha in vivo. Injection of TNF-alpha into s.c. air pouches led to a rapid, transient accumulation of leukocytes. Maximal accumulation of leukocytes in the air pouch was observed at between 2 and 4 h after injection of TNF-alpha. The cellular exudate comprised predominantly neutrophils, with smaller numbers of eosinophils and mononuclear phagocytes also being recruited. However, lymphocyte recruitment was not observed. TNF-alpha injection induced a time-dependent increase in the levels of immunoreactive macrophage inflammatory protein (MIP)-2, MIP-1alpha, and JE in the pouch exudate as well as increased steady-state mRNA levels of KC, MIP-2, MIP-1alpha, and JE in the tissue lining the s.c. pouch and of MIP-2, MIP-1alpha, and JE in the exudate cell population. Passive immunization with specific Abs directed against each of these chemokines significantly inhibited the accumulation of neutrophils, mononuclear phagocytes, and eosinophils in response to TNF-alpha. Taken together, these data demonstrate the existence of a chemokine network in vivo involving at least four individual chemokines that regulates recruitment of the major peripheral blood granulocytes and mononuclear phagocytes to s.c. sites during acute inflammation. To our knowledge, these data are also the first demonstration that the C-C chemokine JE is involved in neutrophil recruitment in a physiologic system in vivo.
TL;DR: It is shown that antioxidant compounds in red wine can associate with LDL particles following an incubation in whole plasma, can exert an antioxidant effect and, in so doing, can inhibit the uptake of the lipoprotein by macrophages.
TL;DR: Southern, northern, and western analyses revealed that VVTL1 is found in the berry only and is encoded by a single gene that is expressed in conjunction with the onset of sugar accumulation and softening, indicating that the presence of thaumatin-like proteins in ripening fruit might be a widespread phenomenon.
Abstract: The protein composition of the grape (Vitis vinifera cv Muscat of Alexandria) berry was examined from flowering to ripeness by gel electrophoresis. A protein with an apparent molecular mass of 24 kD, which was one of the most abundant proteins in extracts of mature berries, was purified and identified by amino acid sequence to be a thaumatin-like protein. Combined cDNA sequence analysis and electrospray mass spectrometry revealed that this protein, VVTL1 (for V. vinifera thaumatin-like protein 1), is synthesized with a transient signal peptide as seen for apoplastic preproteins. Apart from the removal of the targeting signal and the formation of eight disulfide bonds, VVTL1 undergoes no other posttranslational modification. Southern, northern, and western analyses revealed that VVTL1 is found in the berry only and is encoded by a single gene that is expressed in conjunction with the onset of sugar accumulation and softening. The exact role of VVTL1 is unknown, but the timing of its accumulation correlates with the inability of the fungal pathogen powdery mildew (Uncinula necator) to initiate new infections of the berry. Western analysis revealed that the presence of thaumatin-like proteins in ripening fruit might be a widespread phenomenon.
TL;DR: A 70-d test with cattle weighed every 2 wk seems to be optimal for measuring these traits in British breed cattle.
Abstract: The optimum duration of test for measurement of growth rate, feed intake, feed conver- sion, and residual feed intake was examined using postweaning feed intake and weight data from 760 Angus, Hereford, Polled Hereford, and Shorthorn heifer and Angus bull progeny from 78 sires. Variance components, heritability, phenotypic and genetic correlations, and the efficiency of selection using shortened tests compared with a 119-d test were used as criteria to assess the optimum test length. The results indicated that a 35-d test was sufficient for measurement of feed intake, whereas a 70-d test was required to measure growth rate, feed conversion, and residual feed intake without compromising the ac- curacy of measurement. When a 70-d test is used to measure growth rate, feed conversion, and residual feed intake there is minimal loss in accuracy when weights are collected every 2 wk instead of weekly, but a further increase in the interval between weights to 5 wk caused a decline in the accuracy of the test. Therefore a 70-d test with cattle weighed every 2 wk seems to be optimal for measuring these traits in British breed cattle.
TL;DR: A review of the literature relating to supernumerary teeth is presented along with four case reports to illustrate some possible presentations, diagnostic features, and treatment options.
Abstract: A review of the literature relating to supernumerary teeth is presented along with four case reports to illustrate some possible presentations, diagnostic features, and treatment options.
28 Nov 1997
TL;DR: Bulbeck as discussed by the authors examines debates on human rights, family relationships, sexuality, and notions of the individual and community to show how their meanings and significance in different parts of the world contest the issues which preoccupy contemporary Anglophone feminists.
Abstract: The agenda of contemporary western feminism focuses on equal participation in work and education, reproductive rights, and sexual freedom. But what does feminism mean to the women of rural India who work someone else's fields, young Thai girls in the sex industry in Bangkok, or Filipino maids working for wealthy women in Hong Kong? In this 1998 book, Chilla Bulbeck presents a bold challenge to the hegemony of white, western feminism in this incisive and wide-ranging exploration of the lived experiences of 'women of colour'. She examines debates on human rights, family relationships, sexuality, and notions of the individual and community to show how their meanings and significance in different parts of the world contest the issues which preoccupy contemporary Anglophone feminists. She then turns the focus back on Anglo culture to illustrate how the theories and politics of western feminism are viewed by non-western women.
TL;DR: The structure of this higher plant ion transport protein is unique and contains PEST sequences, which suggests that the protein contains 8-10 transmembrane helices and a hydrophilic amino terminus containing sequences enriched in Pro, Ser, Thr, and Glu (PEST).
Abstract: The transport of cations across membranes in higher plants plays an essential role in many physiological processes including mineral nutrition, cell expansion, and the transduction of environmental signals In higher plants the coordinated expression of transport mechanisms is essential for specialized cellular processes and for adaptation to variable environmental conditions To understand the molecular basis of cation transport in plant roots, a Triticum aestivum cDNA library was used to complement a yeast mutant deficient in potassium (K+) uptake Two genes were cloned that complemented the mutant: HKT1 and a novel cDNA described in this report encoding a cation transporter, LCT1 (low-affinity cation transporter) Analysis of the secondary structure of LCT1 suggests that the protein contains 8–10 transmembrane helices and a hydrophilic amino terminus containing sequences enriched in Pro, Ser, Thr, and Glu (PEST) The transporter activity was assayed using radioactive isotopes in yeast cells expressing the cDNA LCT1 mediated low-affinity uptake of the cations Rb+ and Na+, and possibly allowed Ca2+ but not Zn2+ uptake LCT1 is expressed in low abundance in wheat roots and leaves The precise functional role of this cation transporter is not known, although the competitive inhibition of cation uptake by Ca2+ has parallels to whole plant and molecular studies that have shown the important role of Ca2+ in reducing Na+ uptake and ameliorating Na+ toxicity The structure of this higher plant ion transport protein is unique and contains PEST sequences
TL;DR: In contrast to studies suggesting that rugae move forward with age, the majority of Aboriginal rugae that changed direction moved posteriorly, and there was a statistically significant association between rugae forms and ethnicity, straight forms being more common in Caucasians whereas wavy forms were more common Aborigines.
Abstract: The purpose of this study was to determine whether rugae patterns change with age and to compare the number and pattern of rugae in Australian Aborigines with those of Caucasians. For the longitudinal part of the study, serial dental casts of ten Aborigines, from 6 to 20 years of age, were examined and rugae patterns were recorded. To enable comparisons to be made between different ethnic groups an additional 100 dental casts of Australian Aborigines and 200 casts of caucasians, ranging in age from 13 to 17 years, were examined. Characteristics observed were number, length, shape, direction and unification of rugae. The length of rugae increased significantly with age but the total number of rugae remained constant. Thirty-two per cent of rugae showed changes in shape, while 28 per cent displayed a change in orientation. In contrast to studies suggesting that rugae move forward with age, the majority of Aboriginal rugae that changed direction moved posteriorly. Changes in rugae patterns have been assumed to result from palatal growth but alterations in pattern were observed in the Aboriginal sample even after palatal growth had ceased. The mean number of primary rugae in Aborigines was higher than in Caucasians, although more primary rugae in Caucasians exceeded 10 mm in length than in Aborigines. The most common shapes in both ethnic groups were wavy and curved forms, whereas straight and circular types were least common. There was a statistically significant association between rugae forms and ethnicity, straight forms being more common in Caucasians whereas wavy forms were more common Aborigines.