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Context: Barley grass (Hordeum spp. L.) is an annual, invasive grass weed of southern Australian crops and pastures, frequently associated with weight loss and carcass damage in sheep due to its sharp seeds. Knowledge gaps exist regarding optimal density thresholds for effective control to reduce impacts on animal production. The value of integrated weed management (IWM) over individual control options for reducing barley grass populations in pasture is also unknown. Aims: We aimed to develop a model for simulating the population dynamics of barley grass within lucerne (Medicago sativa L.) pastures of southern Australia and to test the hypothesis that combining herbicides with mowing will be more effective for removing barley grass seedbanks over time than individual control measures. Methods: The model was developed within Microsoft Excel and adapted from other annual grass models. The model takes a Monte Carlo approach to simulate control impacts on weed seedbanks over 10 years using five weed-control density thresholds. It was parameterised using data from recent experiments and available literature. Key results: The most effective long-term control strategy for barley grass occurred with a density threshold of 5 seedlings m−2 by combining early and late herbicide applications, and by combining early and late herbicides with mowing, reducing the seedbank by 86% and 89%, respectively. Conclusions: Simulation results showed that IWM programs were more effective than individual control options in reducing the barley grass seedbanks over 10 years, particularly at low weed densities (≤50 seedlings m−2). Implications: Incorporation of this model into a bioeconomic grazing systems model will be valuable for determining the economic impacts and optimal weed-control strategies for minimising the effects of barley grass seed contamination in lamb production systems. Barley grass is an invasive weed in southern Australia, with sharp seeds that can penetrate the flesh of grazing sheep, affecting production and animal welfare. Using a simulation modelling approach, this study compared the efficacy of single versus combined weed management strategies on barley grass populations within a lucerne pasture over 10 years. Combined control practices were found superior for reducing seed production, and the reported approach will enable the selection of optimal control strategies for reducing impacts on livestock production. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2008.12.008 Byline: Jane C. Quinn (a)(b), Michael Molinek (a), John O. Mason (a), David J. Price (a) Keywords: Gli3; Telencephalon; Mouse; Chimera; Forebrain Abstract: The Gli3 zinc finger transcription factor is expressed in developing forebrain, with the highest levels of expression in dorsal telencephalon. In Gli3.sup.-/- embryos the dorsal telencephalon is abnormally small and fails to develop dorsomedial telencephalic structures, including hippocampus and cortical hem, while the ventral telencephalon appears to expand. A hurdle to understanding the underlying mechanisms is that abnormalities of developing Gli3.sup.-/- telencephalic cells in Gli3.sup.-/- mutants result from a combination of their own cell autonomous defects and defects in the Gli3.sup.-/- cells that surround them. Here we used chimeras to identify some of the defects of Gli3.sup.-/- telencephalic cells that are likely to be autonomous by studying how Gli3.sup.-/- cells develop when surrounded by a majority of wild-type cells. We found that Gli3.sup.-/- cells are present in all components of the Gli3.sup.-/- a Gli3.sup.+/+ chimeric forebrain, including dorsomedial structures, in proportions that either equal or exceed proportions found elsewhere in the embryo. Gli3.sup.-/- cells segregate from Gli3.sup.+/+ cells to form many abnormal structures particularly in dorsal telencephalon. Gli3.sup.-/- cells in some locations are misspecified: in those parts of the dorsal telencephalon near to its boundaries with the diencephalon and the ventral telencephalon, mutant cells express sets of transcription factors expressed by wild-type cells on the other side of the boundary. Elsewhere in the dorsal telencephalon, in the diencephalon and in the ventral telencephalon, mutant cells express sets of transcription factors similar to those expressed by their immediately surrounding wild-type cells. We propose that an important cell autonomous action of Gli3 is to regulate the competence of dorsal telencephalic cells, preventing cells near to its boundaries expressing regulatory factors normally restricted to adjacent tissues. Author Affiliation: (a) Centre for Integrative Physiology, The University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK (b) School of Veterinary and Animal Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia Article History: Received 17 September 2008; Revised 9 December 2008; Accepted 10 December 2008

Context: Biserrula (Biserrula pelecinus L.) is a relatively new legume species in Australia that has been shown to maintain higher quality forage late in the season than subterranean clover (Trifolium subterraneum L.). Aim: This study investigated the suitability of lucerne (Medicago sativa L.), subterranean clover and biserrula, or a choice of both biserrula and subterranean clover, for finishing White Dorper and White Suffolk × Merino lambs during spring. Methods: An experiment was established near Wagga Wagga, NSW, in 2013 in a randomised complete block design with three replicates and four pasture treatments grazed by lambs during late spring and early summer. Liveweight, carcass weight and GR fat depth of White Dorper and White Suffolk × Merino lambs grazing lucerne, subterranean clover, biserrula or a choice of subterranean clover plus biserrula were compared. Key results: Lambs grazing lucerne had significantly (P < 0.05) higher final liveweight, carcass weight and GR fat depth than lambs grazing other pasture treatments. After 61 days of grazing, mean liveweight of lambs grazing lucerne, subterranean clover and subterranean clover plus biserrula was higher than of lambs grazing biserrula monoculture. In vitro digestible organic matter digestibility and crude protein content indicated that lambs grazing biserrula should have achieved growth rates at least as high as lambs grazing subterranean clover. Sheep genotype and pasture type affected final liveweight. Final liveweight was higher for White Dorper lambs when grazing the subterranean clover plus biserrula treatment than the subterranean clover monoculture (45.6 vs 44.5 kg; P < 0.05) but was similar for White Suffolk × Merino lambs grazing these treatments (47.3 vs 47.2 kg; P > 0.05). Conclusions: Provision of a companion species or mixture of species when lambs graze biserrula during late spring to summer appears to offer benefits for lamb growth rate over this period. Utilising pastures that maintain high quality later in the season can allow higher finished weights for lambs grazing pasture. Biserrula forage maintained higher digestibility and crude protein levels later in the season than subterranean clover; however, growth rates were lower for lambs grazing biserrula than other pastures during late spring. Provision of a companion species or mixture of species when lambs graze biserrula during late spring to summer appears to offer benefits for lamb growth rate over this period. [ABSTRACT FROM AUTHOR]

Abstract Background The transcription factor Foxg1 is an important regulator of telencephalic cell cycles. Its inactivation causes premature lengthening of telencephalic progenitor cell cycles and increased neurogenic divisions, leading to severe hypoplasia of the telencephalon. These proliferation defects could be a secondary consequence of the loss of Foxg1 caused by the abnormal expression of several morphogens (Fibroblast growth factor 8, bone morphogenetic proteins) in the telencephalon of Foxg1 null mutants. Here we investigated whether Foxg1 has a cell autonomous role in the regulation of telencephalic progenitor proliferation. We analysed Foxg1+/+↔Foxg1-/- chimeras, in which mutant telencephalic cells have the potential to interact with, and to have any cell non-autonomous defects rescued by, normal wild-type cells. Results Our analysis showed that the Foxg1-/- cells are under-represented in the chimeric telencephalon and the proportion of them in S-phase is significantly smaller than that of their wild-type neighbours, indicating that their under-representation is caused by a cell autonomous reduction in their proliferation. We then analysed the expression of the cell-cycle regulator Pax6 and found that it is cell-autonomously downregulated in Foxg1-/- dorsal telencephalic cells. We went on to show that the introduction into Foxg1-/- embryos of a transgene designed to reverse Pax6 expression defects resulted in a partial rescue of the telencephalic progenitor proliferation defects. Conclusions We conclude that Foxg1 exerts control over telencephalic progenitor proliferation by cell autonomous mechanisms that include the regulation of Pax6, which itself is known to regulate proliferation cell autonomously in a regional manner.

Abstract Background Embryonic stem (ES) cells can differentiate into all cell types and have been used extensively to study factors affecting neuronal differentiation. ES cells containing mutations in known genes have the potential to provide useful in vitro models for the study of gene function during neuronal differentiation. Recently, mouse ES cell lines lacking the neurogenic transcription factor Pax6 were reported; neurons derived from these Pax6-/- ES cells died rapidly after neuronal differentiation in vitro. Results Here we report the derivation of new lines of Pax6-/- ES cells and the assessment of their ability to survive and differentiate both in vitro and in vivo. Neurons derived from our new Pax6-/- lines were viable and continued to elaborate processes in culture under conditions that resulted in the death of neurons derived from previously reported Pax6-/- ES cell lines. The new lines of Pax6-/-ES cells showed reduced neurogenic potential, mimicking the effects of loss of Pax6 in vivo. We used our new lines to generate Pax6-/- ↔ Pax6+/+ chimeras in which the mutant cells survived and displayed the same phenotypes as Pax6-/- cells in Pax6-/- ↔ Pax6+/+ chimeras made by embryo aggregation. Conclusions We suggest that loss of Pax6 from ES cells reduces their neurogenic capacity but does not necessarily result in the death of derived neurons. We offer these new lines as additional tools for those interested in the generation of chimeras and the analysis of in vitro ES cell models of Pax6 function during neuronal differentiation, embryonic and postnatal development.

Hordeum spp. (barley grass) and Bromus spp. (brome grass) are annual weed species that achieve long‐distance seed dispersal via attachment to sheep, but also lead to sheep carcass damage due to the penetration of seeds into animal tissues. Range expansion of invasive weed populations predicted as a consequence of climate change may be associated with an increase in seed contamination incidence globally. An examination of Australian abattoir data (2006–2012), along with recent weed distribution patterns, indicates carcass contamination was associated with rainfall and abundance of key annual grass weeds, primarily Bromus spp. and Hordeum spp., although other factors may play a contributing role. Significant differences in seed contamination in slaughtered sheep were noted between states and regions, with widespread contamination occurring throughout all agro‐ecological zones. Abattoir, sheep age and sex significantly influenced incidence, with contamination highest in adult males. Incidence increased with mean monthly rainfall, but declined with mean elevation, and significant interactions were noted between mean monthly temperature and state, and between mean elevation and year. Results show the need for vigilant recording of seed injuries in sheep to enhance weed surveillance efforts and effective integrated weed management of contributing annual grass weeds. [ABSTRACT FROM AUTHOR]

Background: Photosensitisation is a clinical condition occurring in both humans and animals that causes significant injury to affected individuals. In livestock, outbreaks of photosensitisation caused by ingestion of toxic plants are relatively common and can be associated with significant economic loss. Objectives: The agents that are most commonly implicated in outbreaks of photosensitisation have not been formally investigated on a global scale. To address this question, a systematic review of the literature was undertaken to determine the most common causative agents implicated in outbreaks of photosensitisation in livestock in Australia and globally, as well as the prevalence and morbidity of such outbreaks. Methods: A systematic database search was conducted to identify peer-reviewed case reports of photosensitisation in livestock published worldwide between 1900 and April 2018. Only case reports with a full abstract in English were included. Non peer-reviewed reports from Australia were also investigated. Case reports were then sorted by plant and animal species, type of photosensitisation by diagnosis, location, morbidity and mortality rate and tabulated for further analysis. Results: One hundred and sixty-six reports qualified for inclusion in this study. Outbreaks were reported in 20 countries. Australia (20), Brazil (20) and the United States (11) showed the highest number of peer-reviewed photosensitisation case reports from this analysis. Hepatogenous (Type III) photosensitisation was the most frequently reported diagnosis (68.5%) and resulted in higher morbidity. Panicum spp., Brachiaria spp. and Tribulus terrestris were identified as the most common causes of hepatogenous photosensitisation globally. Conclusions: Hepatogenous photosensitisation in livestock represents a significant risk to livestock production, particularly in Australia, Brazil, and the United States. Management of toxic pastures and common pasture weeds may reduce the economic impact of photosensitisation both at a national and global level. [ABSTRACT FROM AUTHOR]

Mixed farming systems have traditionally incorporated subterranean clover (Trifolium subterraneum L.) and lucerne (Medicago sativa L.) as key components of the pasture phase across south-eastern Australia. However, poor adaptation of subterranean clover to acidic soils, insufficient and inconsistent rainfall, high input costs, soil acidification and the emergence of herbicide-resistant weeds have reduced efficacy of some traditional clover species in recent years. To overcome these challenges, numerous novel pasture species have been selectively improved and released for establishment in Australia. Despite their suitability to Australian climate and soils, limited knowledge exists regarding their weed-suppressive ability in relation to establishment and regeneration. Field trials were therefore conducted over 3 years in New South Wales to evaluate the suppressive potential of selected pasture legume species and cultivars as monocultures and in mixed stands against dominant annual pasture weeds. Pasture and weed biomass varied significantly between pasture species when sown as monocultures, but mixtures of several species did not differ with regard to establishment and subsequent weed infestation. Arrowleaf clover (T. vesiculosum Savi.) and biserrula (Biserrula pelecinus L.) cv. Casbah showed improved stand establishment, with higher biomass and reduced weed infestation compared with other pasture species. Generally, weed suppression was positively correlated with pasture biomass; however, yellow serradella (Ornithopus compressus L.) cv. Santorini exhibited greater weed suppression than other pasture legumes while producing lower biomass, thereby suggesting a mechanism other than competition for resources affecting weed-suppressive ability. Over the period 2015–17, arrowleaf clover and biserrula cv. Casbah were generally the most consistent annual pasture legumes with respect to yearly regeneration and suppression of annual pasture weed species. Results of 3 years of field experimentation using a variety of annual pasture legumes demonstrated that arrowleaf clover and biserrula were the most consistent and competitive annual legumes with respect to stand establishment, yearly regeneration and consistent suppression of common pasture weed species. Multivariate analysis revealed weed suppressive potential of annual pasture legumes including biserrula cv. Casbah and yellow serradella were due to mechanisms other than competition for resources. [ABSTRACT FROM AUTHOR]

We describe the clinicopathologic features of a mortality event characterized by blindness and dermatitis affecting eastern grey kangaroos ( Macropus giganteus), secondary to hepatogenous photosensitization. Affected animals exhibited photophobic behavior, blindness, ataxia, recumbency, lethargy, ear shaking, and behavior consistent with distress or depression. The photophobia manifested as abnormal shade-seeking during the day, including finding refuge under or in structures used frequently by people. Severely affected kangaroos were jaundiced and had markedly elevated serum bilirubin and gamma glutamyl-transpeptidase concentrations. Blindness in affected animals was attributed to moderate to severe corneal opacity due to corneal edema and inflammation. Skin lesions were typically subtle on gross examination even in cases which had severe necrotizing dermatitis histologically. Histologic lesions in the liver of affected animals included the presence of acicular clefts typical of steroidal saponins. The outbreak was associated with pasture dominated by the invasive grass, Panicum gilvum, which is a recognized source of saponin-induced photosensitization in livestock. [ABSTRACT FROM AUTHOR]

Background: Primary photosensitisation (PS) subsequent to ingestion of the pasture legume Biserrula pelecinus L. (biserrula) has recently been confirmed in grazing livestock. Given the potential utility of this pasture species in challenging climates, a grazing trial was undertaken to examine if both varieties 'Casbah' and 'Mauro' were able to cause photosensitisation in livestock, and if this could be mitigated by grazing in winter, or in combination with other common pasture species. Results: A controlled grazing trial was undertaken in winter in Australia with plots containing a dominant pasture of Biserrula pelecinus L. cv. 'Casbah' or 'Mauro', or mixed biserrula/perennial ryegrass populations. A photosensitisation grading system was established. 167 prime meat ewe lambs were introduced to the plots and monitored twice daily. Mild clinical signs were observed at 72 h on pasture. All animals were removed from biserrula dominant stands at this point. Four animals grazing 'Casbah' dominant pasture rapidly proceeded to severe photosensitisation in the following 12 h. Animals remaining on mixed biserrula/ryegrass stands did not exhibit severe PS but showed an 89% incidence of mild to moderate photosensitisation over the following 14 days. Animals on mixed lucerne showed significantly lower PS score than animals grazing biserrula varieties of any composition. The trial was halted at 14 days as only plots with low biserrula proportion still contained unaffected animals. Necropsy revealed severe multifocal erythematous ulcerations and alopecia of the ear pinnae, severe bilateral periorbital and conjunctival oedema and variably severe subcutaneous facial oedema. No evidence of hepatopathy was present. A diagnosis of acute unseasonal primary photosensitisation caused by biserrula ingestion with no other underlying pathology was confirmed. Conclusions: We report an unseasonal outbreak of acute photosensitisation in sheep grazing Biserrula pelecinus L cvs.'Casbah' and 'Mauro' with exceedingly high morbidity. A grading system is also proposed as a tool for objective and consistent clinical appraisal of future PS outbreaks. This finding expands our definition of seasonal and temporal risk periods for biserrula photosensitisation, and is the first to identify that both commercial cultivars of biserrula can cause primary photosensitisation in sheep. [ABSTRACT FROM AUTHOR]

Herbicide resistance in both grasses and broadleaf weeds is on the rise across Australia, with an increasing number of cropping weeds experiencing resistance to multiple herbicides. One contributing factor to this issue is the adoption of conservation agriculture (CA). CA is a system of residue management that avoids the use of cultivation for establishment of annual broadacre crops. Another contributing factor is poor management of herbicide mode of action strategies in broadacre farming. One key tool for integrated weed management (IWM) strategies is the use of competitive grain crop cultivars and post-harvest crop residues, which can effectively suppress or delay weed seedling emergence and provide an initial advantage for the crop in terms of early weed suppression. The ability of various dual-purpose grazing or non-grazing grain crops and their residues to suppress weeds until subsequent planting the following year was compared in two successive field experiments in the Riverina region of New South Wales (NSW), Australia. We evaluated 1) the impact of residues of several grain crops on winter and post-harvest summer annual weed establishment from 2012 to 2014 and 2) in-crop and post-harvest weed suppression in 2014–2015 using a genetically diverse set of canola cultivars, including those found to be highly weed-suppressive in the first trial. Replicated field trials were established in Wagga Wagga, in a moderate rainfall zone (mean 572 mm/year) from 2012 to 2015 using commercially available crop cultivars. Differences in in-crop weed infestation and in post-harvest crop fallows associated with grain crop cultivar and species were observed in each of three years. Significant weed suppression associated with grazing and non-grazing wheat residues was observed after harvest, with grazing wheat exhibiting significant suppression of fleabane and witchgrass up to 130 days post-harvest. Grazing and non-grazing canola provided strong and significant suppression of fleabane and witchgrass for up to 140 days following harvest. Grazing cereal cultivars were generally more suppressive of weeds than non-grazing cultivars. Early vigour and ability to intercept light and accumulate biomass resulted in suppression of in-crop weed growth in canola trials, with GT-50 the most weed suppressive canola cultivar. Weed biomass differed with cultivar in both years, and appeared to be inversely related to early crop vigour, suggesting the importance of crop biomass in regulating weed competition in the crop. Cultivars CB Taurus and GT-50 were consistently the most weed suppressive when residues remained in plots 150 days post-harvest. These results indicate that establishment of certain species and cultivars of grain crops may effectively suppress weed growth both in-crop and post-harvest, in the absence of post-emergent herbicides. In addition, the choice of canola cultivar for desired weed suppression impacts the subsequent ability of the crop and its residues to successfully interfere with weed growth. [ABSTRACT FROM AUTHOR]

Gene-directed tissue repair offers the clinician, human or veterinary, the chance to enhance cartilage regeneration and repair at a molecular level. Non-viral plasmid vectors have key biosafety advantages over viral vector systems for regenerative therapies due to their episomal integration however, conventional non-viral vectors can suffer from low transfection efficiency. Our objective was to identify and validate in vitro a novel non-viral gene expression vector that could be utilized for ex vivo and in vivo delivery to stromal-derived mesenchymal stem cells (MSCs). Minicircle plasmid DNA vector containing green fluorescent protein (GFP) was generated and transfected into adipose-derived MSCs from three species: canine, equine and rodent and transfection efficiency was determined. Both canine and rat cells showed transfection efficiencies of approximately 40% using minicircle vectors with equine cells exhibiting lower transfection efficiency. A Sox9-expressing minicircle vector was generated and transfected into canine MSCs. Successful transfection of the minicircle-Sox9 vector was confirmed in canine cells by Sox9 immunostaining. This study demonstrate the application and efficacy of a novel non-viral expression vector in canine and equine MSCs. Minicircle vectors have potential use in gene-directed regenerative therapies in non-rodent animal models for treatment of cartilage injury and repair. [ABSTRACT FROM AUTHOR]

Photosensitivity in animals is defined as a severe dermatitis that results from a heightened reactivity of skin cells and associated dermal tissues upon their exposure to sunlight, following ingestion or contact with UV reactive secondary plant products. Photosensitivity occurs in animal cells as a reaction that is mediated by a light absorbing molecule, specifically in this case a plant-produced metabolite that is heterocyclic or polyphenolic. In sensitive animals, this reaction is most severe in non-pigmented skin which has the least protection from UV or visible light exposure. Photosensitization in a biological system such as the epidermis is an oxidative or other chemical change in a molecule in response to light-induced excitation of endogenous or exogenously-delivered molecules within the tissue. Photo-oxidation can also occur in the plant itself, resulting in the generation of reactive oxygen species, free radical damage and eventual DNA degradation. Similar cellular changes occur in affected herbivores and are associated with an accumulation of photodynamic molecules in the affected dermal tissues or circulatory system of the herbivore. Recent advances in our ability to identify and detect secondary products at trace levels in the plant and surrounding environment, or in organisms that ingest plants, have provided additional evidence for the role of secondary metabolites in photosensitization of grazing herbivores. This review outlines the role of unique secondary products produced by higher plants in the animal photosensitization process, describes their chemistry and localization in the plant as well as impacts of the environment upon their production, discusses their direct and indirect effects on associated animal systems and presents several examples of well-characterized plant photosensitization in animal systems. [ABSTRACT FROM AUTHOR]

Background: The transcription factor Foxg1 is an important regulator of telencephalic cell cycles. Its inactivation causes premature lengthening of telencephalic progenitor cell cycles and increased neurogenic divisions, leading to severe hypoplasia of the telencephalon. These proliferation defects could be a secondary consequence of the loss of Foxg1 caused by the abnormal expression of several morphogens (Fibroblast growth factor 8, bone morphogenetic proteins) in the telencephalon of Foxg1 null mutants. Here we investigated whether Foxg1 has a cell autonomous role in the regulation of telencephalic progenitor proliferation. We analysed Foxg1+/+ ↔ Foxg1-/- chimeras, in which mutant telencephalic cells have the potential to interact with, and to have any cell nonautonomous defects rescued by, normal wild-type cells. Results: Our analysis showed that the Foxg1-/- cells are under-represented in the chimeric telencephalon and the proportion of them in S-phase is significantly smaller than that of their wild-type neighbours, indicating that their under-representation is caused by a cell autonomous reduction in their proliferation. We then analysed the expression of the cell-cycle regulator Pax6 and found that it is cell-autonomously downregulated in Foxg1-/- dorsal telencephalic cells. We went on to show that the introduction into Foxg1-/- embryos of a transgene designed to reverse Pax6 expression defects resulted in a partial rescue of the telencephalic progenitor proliferation defects. Conclusions: We conclude that Foxg1 exerts control over telencephalic progenitor proliferation by cell autonomous mechanisms that include the regulation of Pax6, which itself is known to regulate proliferation cell autonomously in a regional manner. [ABSTRACT FROM AUTHOR]

Background: Embryonic stem (ES) cells can differentiate into all cell types and have been used extensively to study factors affecting neuronal differentiation. ES cells containing mutations in known genes have the potential to provide useful in vitro models for the study of gene function during neuronal differentiation. Recently, mouse ES cell lines lacking the neurogenic transcription factor Pax6 were reported; neurons derived from these Pax6-/- ES cells died rapidly after neuronal differentiation in vitro. Results: Here we report the derivation of new lines of Pax6-/- ES cells and the assessment of their ability to survive and differentiate both in vitro and in vivo. Neurons derived from our new Pax6-/- lines were viable and continued to elaborate processes in culture under conditions that resulted in the death of neurons derived from previously reported Pax6-/- ES cell lines. The new lines of Pax6-/-ES cells showed reduced neurogenic potential, mimicking the effects of loss of Pax6 in vivo. We used our new lines to generate Pax6-/- ↔ Pax6+/+ chimeras in which the mutant cells survived and displayed the same phenotypes as Pax6-/- cells in Pax6-/- ↔ Pax6+/+ chimeras made by embryo aggregation. Conclusions: We suggest that loss of Pax6 from ES cells reduces their neurogenic capacity but does not necessarily result in the death of derived neurons. We offer these new lines as additional tools for those interested in the generation of chimeras and the analysis of in vitro ES cell models of Pax6 function during neuronal differentiation, embryonic and postnatal development. [ABSTRACT FROM AUTHOR]

Abstract: Many cerebral cortical neurons and glia are produced by apical progenitors dividing at the ventricular surface of the embryonic dorsal telencephalon. Other neurons are produced by basal progenitor cells, which are derived from apical progenitors, dividing away from the ventricular surface. The transcription factor Pax6 is expressed in apical progenitors and is downregulated in basal progenitors, which upregulate the transcription factor Tbr2. Here we show that Pax6 −/− cells are under-represented in the cortex of Pax6 +/+ ↔Pax6 −/− chimeras early in corticogenesis, indicating that Pax6 is required for the production of normal numbers of cortical cells. We provide evidence that this underproduction is attributable to an early depletion of the progenitor pool caused by greater than normal proportions of newly divided cells exiting the cell cycle. We show that most progenitor cells dividing away from the ventricular surface in Pax6 −/− embryos fail to express the transcription factor Tbr2 and that Pax6 is required cell autonomously for Tbr2 expression in the developing cortex of Pax6 +/+ ↔Pax6 −/− chimeras. Transcription factors normally expressed ventrally in the telencephalic ganglionic eminences (Mash1, Dlx2 and Gsh2) are upregulated cell autonomously in mutant cells in the developing cortex of Pax6 +/+ ↔Pax6 −/− chimeras; Nkx2.1, which is expressed only in the medial ganglionic eminence, is not. These data indicate that early functions of Pax6 in developing cortical cells are to repress expression of transcription factors normally found in the lateral ganglionic eminence, to prevent precocious differentiation and depletion of the progenitor pool, and to induce normal development of cortical basal progenitor cells. [Copyright &y& Elsevier]

Background: Knowledge of the consequences of heterozygous mutations of developmentally important genes is important for understanding human genetic disorders. The Gli3 gene encodes a zinc finger transcription factor and homozygous loss-of-function mutations of Gli3 are lethal. Humans heterozygous for mutations in this gene suffer Greig cephalopolysyndactyly or Pallister- Hall syndromes, in which limb defects are prominent, and mice heterozygous for similar mutations have extra digits. Here we examined whether eye development, which is abnormal in mice lacking functional Gli3, is defective in Gli3+/- mice. Results: We showed that Gli3 is expressed in the developing eye but that Gli3+/- mice have only very subtle eye defects. We then generated mice compound heterozygous for mutations in both Gli3 and Pax6, which encodes another developmentally important transcription factor known to be crucial for eye development. Pax6-; Gli3+/- eyes were compared to the eyes of wild-type, Pax6+/- or Gli3+/- siblings. They exhibited a range of abnormalities of the retina, iris, lens and cornea that was more extensive than in single Gli3+/- or Pax6+/- mutants or than would be predicted by addition of their phenotypes. Conclusion: These findings indicate that heterozygous mutations of Gli3 can impact on eye development. The importance of a normal Gli3 gene dosage becomes greater in the absence of a normal Pax6 gene dosage, suggesting that the two genes co-operate during eye morphogenesis. [ABSTRACT FROM AUTHOR]

As the telencephalon first emerges from anterior neuroectoderm, signalling molecules and transcription factors combine to specify the identity and fate of cells in each of its regions. Studies of both naturally occurring and transgenic mutant mice have identified many genes that contribute to this process. The development of telencephalon and its regions is specified by signalling molecules produced at sites both surrounding and within the telencephalon. Different parts of the telencephalon express different combinations of transcription factors that control processes including proliferation, cell fate determination and migration in order to create the unique phenotype of each region. [Copyright &y& Elsevier]

The roles of Pax6 were investigated in the murine eye and the olfactory epithelium by analysing gene expression and distribution of Pax6−/− cells in Pax6+/+ → Pax6−/− chimeras. It was found that between embryonic days E10.5 and E16.5 Pax6 is autonomously required for cells to contribute fully not only to the corneal epithelium, where Pax6 is expressed at high levels, but also to the to the corneal stroma and endothelium, where the protein is detected at very low levels. Pax6−/− cells contributed only poorly to the neural retina, forming small clumps of cells that were normally restricted to the ganglion cell layer at E16.5. Pax6−/− cells in the retinal pigment epithelium could express Trp2, a component of the pigmentation pathway, at E14.5 and a small number went on to differentiate and produce pigment at E16.5. The segregation and near-exclusion of mutant cells from the nasal epithelium mirrored the behaviour of mutant cells in other developmental contexts, particularly the lens, suggesting that common primary defects may be responsible for diverse Pax6-related phenotypes. [Copyright &y& Elsevier]

Mutations in the Pax6 gene disrupt telencephalic development, resulting in a thin cortical plate, expansion of proliferative layers, and the absence of the olfactory bulb. The primary defect in the neuronal cell population of the developing cerebral cortex was analysed by using mouse chimeras containing a mixture of wild-type and Pax6-deficient cells. The chimeric analysis shows that Pax6 influences cellular activity throughout corticogenesis. At early stages, Pax6-deficient and wildtype cells segregate into exclusive patches, indicating an inability of different cell genotypes to interact. At later stages, cells are sorted further based on telencephalic domains. Pax6-deficient cells are specifically reduced in the mediocaudal domain of the dorsal telencephalon, indicating a role in regionalization. In addition, Pax6 regulates the process of radial migration of neuronal precursors. Loss of Pax6 particularly affects movement of neuronal precursors at the subventricular zone/intermediate zone boundary at a transitional migratory phase essential for entry into the intermediate zone. We suggest that the primary role of Pax6 is the continual regulation of cell surface properties responsible for both cellular identity and radial migration, defects of which cause regional cell sorting and abnormalities of migration in chimeras. [Copyright &y& Elsevier]

Small eye (Pax6 Sey ) is a semi-dominant mutation affecting development of the eyes, brain and nasal structures. The mutant phenotype arises from defects within the Pax6 gene and several mutant alleles have been identified. A previous study reported that Pax6 Sey /Pax6 Sey homozygotes, in a random-bred stock, had a median cartilaginous rod-like structure in the nasal region and 80% had supernumerary upper incisor teeth. In this study we show that supernumerary upper incisor teeth and a previously unreported nasal capsule-derived cartilaginous ’spur’ occur in compound heterozygous Pax6 Sey-Neu /Pax6 Sey and homozygous Pax6 Sey /Pax6 Sey fetuses from several strains of mice. The frequencies of the abnormal phenotypes were not related to allele type but showed variable penetrance, which was dependent on genetic background. The median nasal cartilaginous rod-like structure was present in all homozygous small eye fetuses. The Pax6 Sey /Pax6 Sey homozygote may provide insight into the complex gene interactions involved in eye, nasal and craniofacial morphogenesis. [ABSTRACT FROM AUTHOR]

Herbicide resistance in weeds restricts control options, thereby escalating economic loss and threatening agricultural sustainability in cereal production. Field evaluation of the crop performance, competitive traits, and consequent weed suppressive potential of 13 commercial winter wheat (Triticum aestivum L.) cultivars was performed in central NSW Australia with a focus on the evaluation and modelling of above-ground interactions. In 2015 and 2016, replicated field trials were established with genetically diverse commercial wheat genotypes under moderate to low rainfall conditions in Wagga Wagga (572 mm) and Condobolin (437 mm) New South Wales, respectively. The heritage cultivar Federation and a commercial cultivar of winter cereal rye (Secale cereale L.) were included as known weed-suppressive controls. Crop and weed growth, as well as early vigour, leaf area index, and photosynthetically active radiation, were monitored at various crop phenological stages including early growth, vegetative, flowering, grain fill, and harvest. Significant differences between wheat cultivar and location were observed for crop biomass, early vigour, leaf area index, weed number, weed biomass, canopy architecture, and yield in both 2015 and 2016. Differences in weed establishment were largely impacted first by rainfall and season and secondly by crop architecture (i.e., height, size, canopy) and phenology (i.e., growth stages). Early vigour and early canopy closure were instrumental in suppressing weed establishment and growth. Cultivar performance and competition with weeds were also clearly influenced by both environmental factors and genotype, as evidenced by differences in early cultivar performance, yield, and weed suppression by season and location. Specifically, Federation, Condo, and Janz wheat cultivars were superior performers in terms of weed suppression in both locations and years; however, Federation produced up to 55% lower yield than recently introduced cultivars. Partial least squares (PLS) regression was performed to develop a predictive linear model for weed competition in commercial wheat cultivars based on weed dry biomass as the response variable and selected aboveground crop canopy traits as predictors. In 2015, the model differed in accordance with crop growth stage, but the impact of predictors on weed biomass at both locations was not significant. In 2016, under local above average rainfall conditions, the model showed a significant negative correlation (p < 0.001) of most predictors on weed biomass (r2 = 0.51 at Condobolin, r2 = 0.62 at Wagga Wagga), suggesting the most influential factors in reducing weed numbers and establishment as crop vigour, biomass, and height. Our results indicate the establishment of competitive wheat cultivars in the absence of post-emergent herbicides resulted in a two to five-fold increased weed suppression over less suppressive genotypes, without significant yield penalties. Therefore, cultivar choice constitutes a cost-effective and sustainable weed management tool, particularly when weed pressure is significant. [ABSTRACT FROM AUTHOR]

Background: Embryonic stem (ES) cells can differentiate into all cell types and have been used extensively to study factors affecting neuronal differentiation. ES cells containing mutations in known genes have the potential to provide useful in vitro models for the study of gene function during neuronal differentiation. Recently, mouse ES cell lines lacking the neurogenic transcription factor Pax6 were reported; neurons derived from these Pax6-/- ES cells died rapidly after neuronal differentiation in vitro.Results: Here we report the derivation of new lines of Pax6-/- ES cells and the assessment of their ability to survive and differentiate both in vitro and in vivo. Neurons derived from our new Pax6-/- lines were viable and continued to elaborate processes in culture under conditions that resulted in the death of neurons derived from previously reported Pax6-/- ES cell lines. The new lines of Pax6-/-ES cells showed reduced neurogenic potential, mimicking the effects of loss of Pax6 in vivo. We used our new lines to generate Pax6-/- <--> Pax6+/+ chimeras in which the mutant cells survived and displayed the same phenotypes as Pax6-/- cells in Pax6-/- <--> Pax6+/+ chimeras made by embryo aggregation.Conclusions: We suggest that loss of Pax6 from ES cells reduces their neurogenic capacity but does not necessarily result in the death of derived neurons. We offer these new lines as additional tools for those interested in the generation of chimeras and the analysis of in vitro ES cell models of Pax6 function during neuronal differentiation, embryonic and postnatal development. [ABSTRACT FROM AUTHOR]

Levels of expression of the transcription factor Pax6 vary throughout corticogenesis in a rostro-lateralhigh to caudo-mediallow gradient across the cortical proliferative zone. Previous loss-of-function studies have indicated that Pax6 is required for normal cortical progenitor proliferation, neuronal differentiation, cortical lamination and cortical arealization, but whether and how its level of expression affects its function is unclear. We studied the developing cortex of PAX77 YAC transgenic mice carrying several copies of the human PAX6 locus with its full complement of regulatory regions. We found that PAX77 embryos express Pax6 in a normal spatial pattern, with levels up to three times higher than wild type. By crossing PAX77 mice with a new YAC transgenic line that reports Pax6 expression (DTy54), we showed that increased expression is limited by negative autoregulation. Increased expression reduces proliferation of late cortical progenitors specifically, and analysis of PAX77 ↔wild-type chimeras indicates that the defect is cell autonomous. We analyzed cortical arealization in PAX77 mice and found that, whereas the loss of Pax6 shifts caudal cortical areas rostrally, Pax6 overexpression at levels predicted to shift rostral areas caudally has very little effect. These findings indicate that Pax6 levels are stabilized by autoregulation, that the proliferation of cortical progenitors is sensitive to altered Pax6 levels and that cortical arealization is not. [ABSTRACT FROM AUTHOR]

Abstract Amaranthus retroflexus L., an introduced invasive weed in southern Australia, has been associated with acute renal failure and/or mortality in a number of livestock species. While its leaves, flowers and stems are generally reported to contain high levels of nitrogen, few studies have fully characterised the chemical composition of A. retroflexus foliage with respect to mammalian toxicity. We performed extensive metabolic profiling of stems, leaves, roots and inflorescence tissues of A. retroflexus collected from three spatially and/or temporally distinct toxicity outbreaks, and report on the 1) composition of primary and secondary metabolites in methanolic extracts of A. retroflexus tissues using HPLC and HPLC-MS QToF and 2) chemometric analysis of A. retroflexus extracts in relation to the associated toxin(s). All tissues of A. retroflexus possessed an abundance of N-containing metabolites, particularly quaternary ammonium compounds which were identified as betaines, two of which (valine betaine and isoleucine betaine) are rarely encountered in plants. Cytotoxicity to murine fibroblasts was highest in extracts of leaf tissue and was associated with a single, a small modified peptide with high similarity to N-acetyl-L-α-aspartyl-L-alanyl-L-α-aspartyl-L-α-glutamyl-O-(carboxymethyl)-L-tyrosyl-L-leucinamide, a synthetic phosphotyrosyl mimic involved in cell signaling processes. One possible mode of action leading to acute renal failure in grazing livestock by a modified peptide such as this is proposed. Graphical abstract Image 1 Highlights • All tissues of A. retroflexus contained abundant levels of glycine betaine and related compounds. • We have identified for the first time valine betaine and isoleucine betaine in A. retroflexus. • These are only the second reports of these two uncommon betaines in plants. • In vitro toxicity of A. retroflexus was associated with a small, modified peptide. [ABSTRACT FROM AUTHOR]

The biologically active form of vitamin D3, calcitriol (1,25-(OH)2D3), plays a key role in mineral homeostasis and bone formation and dietary vitamin D3 deficiency is a major cause of bone disorders in poultry. Supplementary dietary cholecalciferol (25-hydroxyvitamin D, 25-OH), the precursor of calcitriol, is commonly employed to combat this problem; however, dosage must be carefully determined as excess dietary vitamin D can cause toxicity resulting in a decrease in bone calcification, hypercalcinemia and renal failure. Despite much research on the therapeutic administration of dietary vitamin D in humans, the relative sensitivity of avian species to exogenous vitamin D has not been well defined. In order to determine the effects of exogenous 1,25-(OH)2D3 during avian osteogenesis, chicken bone marrow-derived mesenchymal stem cells (BM-MSCs) were exposed to varying doses of 1,25-(OH)2D3 during in vitro osteogenic differentiation and examined for markers of early proliferation and osteogenic induction. Similar to humans and other mammals, poultry BM-MSCs were found to be highly sensitive to exogenous 1,25-(OH)2D3 with super pharmacological levels exerting significant inhibition of mineralization and loss of cell proliferation in vitro. Strain related differences were apparent, with BM-MCSs derived from layers strains showing a higher level of sensitivity to 1,25-(OH)2D3 than those from broilers. These data suggest that understanding species and strain specific sensitivities to 1,25-(OH)2D3 is important for optimizing bone health in the poultry industry and that use of avian BM-MSCs are a useful tool for examining underlying effects of genetic variation in poultry. [ABSTRACT FROM AUTHOR]

Currently, there is no standardized rearing method or production guidelines for non-replacement male dairy calves that maximizes their economic viability. Producers have highlighted the need to match consumer expectations, but even with broadscale welfare improvement across the dairy industry, challenges remain at providing reliable and valuable pathways for non-replacement male dairy calves for beef production. A key consumer concern has been the use of on-farm euthanasia. Euthanasia has been a catalyst for change in the industry from a human and animal welfare perspective. The practice of euthanasia can lead to a decline in personnel wellbeing. To investigate the relationship between on-farm management practices of non-replacement male dairy calves and producer perceptions of their value proposition, an online questionnaire was provided to Australian dairy producers between June and October 2021. The aim was to identify supply-chain profitability of non-replacement male calves and investigate the attitudes and effects of euthanasia on producer wellbeing as part of managing these calves. A total of 127 useable responses were obtained, and a Bayesian network (BN) was utilized to model the interdependencies between management practices and wellbeing among participants. The results indicated that in general, dairy producers desired high welfare standards in their enterprises with regard to non-replacement male calves as well as expressed a desire to meet industry and consumers' expectations. In line with anecdotal reports of a reduction in practice, euthanasia was not identified as common practice in this group; however, producers were still accessing early-life markets for non-replacement male calves with operational requirements and environmental factors influencing their decisions. Producers expressed dissatisfaction with market access for their calves, as well as the lack of suitability of Australian beef grading standards for dairy-bred carcasses. Australian dairy managers and owners identified that euthanasia influenced employee wellbeing; however, they did not acknowledge euthanasia had an effect on their own wellbeing. Overall, the findings of this study indicate that all non-replacement male calf breeds had the potential to access profitable markets, and avoidance of euthanasia is a strong driver of change among dairy beef production systems in Australia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Vicic, Saliba, Campbell, Xie and Quinn.)

Qualitative and quantitative PCR-based tests are widely used in both diagnostics and research to assess the prevalence of disease-causing pathogens in veterinary medicine. The efficacy of these tests, usually measured in terms of sensitivity and specificity, is critical in confirming or excluding a clinical diagnosis. We undertook a meta-analysis to assess the inherent value of published PCR diagnostic approaches used to confirm and quantify bacteria and viruses associated with bovine respiratory disease (BRD) in cattle. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A thorough search of nine electronic databases (Web of Science, EBSCOhost, Cambridge journals online, ProQuest, PubMed, Sage journals online, ScienceDirect, Wiley online library and MEDLINE) was undertaken to find studies that had reported on the use of PCR and/or qPCR for the detection and/or quantification of BRD associated organisms. All studies meeting the inclusion criteria for reporting quantitative PCR for identification of BRD associated microorganisms were included in the analysis. Studies were then assessed on the applications of the Minimum Information for Publication of Quantitative Real-Time PCR Experiment (MIQE) and PCR primer/probe sequences were extracted and tested for in silico specificity using a high level of stringency. Fourteen full-text articles were included in this study. Of these, 79% of the analysed articles did not report the application of the MIQE guidelines in their study. High stringency in silico testing of 144 previously published PCR primer/probe sequences found many to have questionable specificity. This review identified a high occurrence of primer/probe sequences with a variable in silico specificity such that this may have implications for the accuracy of reporting. Although this analysis was only applied to one specific disease state, identification of animals suspected to be suffering from bovine respiratory disease, there appears to be more broadly a need for veterinary diagnostic studies to adopt international best practice for reporting of quantitative PCR diagnostic data to be both accurate and comparable between studies and methodologies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Barnewall, Marsh and Quinn.)

Male non-replacement calves in dairy systems represent an underutilized economic resource for dairy producers worldwide. Despite this, increasing the practice of rearing non-replacement male calves has significant barriers both in on-farm adoption and practice. Poor neonatal rearing practices, higher levels of morbidity and mortality, and disaggregated production pathways with multiple points of handling, have all been described as barriers to adoption of surplus calf production. To identify the critical decision-determining challenges associated with broader adoption of raising non-replacement stock, and to investigate the whole-of-value chain issues faced by dairy producers to rear non-replacement male calves, we undertook a series of semi-structured interviews with Australian dairy producers to interrogate their key challenges. To achieve this, a constructivist grounded theory approach was used to inform the process of analysis of in-depth interviews with Australian dairy producers regarding their current practices and perceptions. Five major themes emerged from these conversations that were key barriers to on-farm non-replacement calf rearing in the producer group participants. These were: impacts of drought on cost and availability of feed for these calves and the whole herd; the management requirements of non-replacement male calves as an additional workload to that of their current operation; their attitudes and current practices to and surrounding euthanasia; perceived ease of supply-chain access for these calves, and their perceptions of the economic value of dairy-beef product as a return on investment. Understanding the barriers to adoption of non-replacement calf rearing, and addressing the value proposition for dairy beef, can assist increased uptake of non-replacement calf rearing. These findings will allow development of strategies to address these barriers, and extension of viable management strategies to increase adoption of profitable business practices surrounding non-replacement male calf production., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Vicic, Saliba, Campbell and Quinn.)

The biologically active form of vitamin D₃, calcitriol (1,25-(OH)₂D₃), plays a key role in mineral homeostasis and bone formation and dietary vitamin D₃deficiency is a major cause of bone disorders in poultry. Supplementary dietary cholecalciferol (25-hydroxyvitamin D, 25-OH), the precursor of calcitriol, is commonly employed to combat this problem; however, dosage must be carefully determined as excess dietary vitamin D can cause toxicity resulting in a decrease in bone calcification, hypercalcinemia and renal failure. Despite much research on the therapeutic administration of dietary vitamin D in humans, the relative sensitivity of avian species to exogenous vitamin D has not been well defined. In order to determine the effects of exogenous 1,25-(OH)₂D₃during avian osteogenesis, chicken bone marrow-derived mesenchymal stem cells (BM-MSCs) were exposed to varying doses of 1,25-(OH)₂D₃during in vitro osteogenic differentiation and examined for markers of early proliferation and osteogenic induction. Similar to humans and other mammals, poultry BM-MSCs were found to be highly sensitive to exogenous 1,25-(OH)₂D₃with super pharmacological levels exerting significant inhibition of mineralization and loss of cell proliferation in vitro. Strain related differences were apparent, with BM-MCSs derived from layers strains showing a higher level of sensitivity to 1,25-(OH)₂D₃than those from broilers. These data suggest that understanding species and strain specific sensitivities to 1,25-(OH)₂D₃is important for optimizing bone health in the poultry industry and that use of avian BM-MSCs are a useful tool for examining underlying effects of genetic variation in poultry., (© The Author 2015. Published by Oxford University Press on behalf of Poultry Science Association.)

By using a custom-made array containing cDNAs preferentially expressed in the mouse embryonic telencephalon (Porteus et al. [1992] Brain Res Mol Brain Res 12:7-22; and Alessandro Bulfone, unpublished data), we studied the gene expression profile of the Dlx1/Dlx2(-/-) subpallium and Pax6(-/-) pallium. We identified a transcript corresponding to Unigene Cluster Mm.94021 and rat Evf-1, which is down-regulated in the Dlx1/Dlx2(-/-) subpallium and up-regulated in the Pax6(-/-) pallium. Here, we report the expression pattern of this transcript, designated mouse Evf1 (mEvf1), in the prenatal forebrain of wild-type, Dlx1/Dlx2(-/-) and Pax6(-/-) mice using RNA in situ hybridization and reverse transcriptase-polymerase chain reaction. In the wild-type forebrain mEvf1 expression is restricted to the ventral thalamus, hypothalamus, and subpallial telencephalon (caudal, lateral, and medial ganglionic eminences and septal primordia), whereas it is down-regulated in the Dlx1/Dlx2(-/-) subpallium (mainly in caudal, lateral, and medial ganglionic eminences), and up-regulated in the Pax6(-/-) lateral and ventral pallium at embryonic day 12.5 and in the dorsal, lateral, and ventral pallium at embryonic day 14.5., ((c) 2004 Wiley-Liss, Inc.)

Early events in the formation of the thalamocortical tract remain poorly understood. Recent work has suggested that thalamocortical axons follow a path pioneered by transient thalamic afferents originating from the medial part of the ventral telencephalon. We studied the development of these transient afferents and the thalamocortical tract in mutant mice lacking transcription factors normally expressed in the dorsal thalamus or ventral telencephalon. Pax6 is expressed in the dorsal thalamus, but not in the medial part of the ventral telencephalon, and the thalamocortical tract fails to form in Pax6(-/-) embryos. We found that transient thalamic afferents from the ventral telencephalon do not form in Pax6(-/-) embryos; this may contribute to the failure of their thalamocortical development. The distribution of Pax6(-/-) cells in Pax6(-/-)<--> Pax6(+/+) chimeras supports conclusions drawn from forebrain marker gene expression that Pax6 is not required for the normal development of the medial part of the ventral telencephalon but is required in the dorsal thalamus. Failure of the transient afferent pathway to develop is therefore likely a cell nonautonomous defect reflecting primary defects in the thalamus. We then examined the formation of thalamic afferents and efferents in Foxg1(-/-) embryos, which lack recognizable ventral telencephalic structures. In these embryos thalamic efferents navigate correctly through the thalamus but fail to turn laterally into the telencephalon, whereas other axons are able to cross the diencephalic/telencephalic boundary. Our results support a role for the ventral telencephalon in guiding the early development of the thalamocortical tract and identify a new role for the transcription factor Pax6 in regulating the ability of the thalamus to attract ventral telencephalic afferents.