Identification of the genes encoding the catalytic steps corresponding to LRA4 (l-2-keto-3-deoxyrhamnonate aldolase) and l-lactaldehyde dehydrogenase in Aspergillus nidulans: evidence for involvement of the loci AN9425/lraD and AN0544/aldA in the l-rhamnose catabolic pathway.

l-rhamnose is found in nature mainly as a component of structural plant polysaccharides and can be used as a carbon source by certain microorganisms. Catabolism of this sugar in bacteria, archaea and fungi occurs by two routes involving either phosphorylated or non-phosphorylated intermediates. Unlike the corresponding pathway in yeasts, the metabolic details of the non-phosphorylated pathway in filamentous fungi are not fully defined. The first three genes (lraA, lraB and lraC) of the non-phosphorylated pathway in Aspergillus nidulans have recently been studied revealing dependence on lraA function for growth on l-rhamnose and α-l-rhamnosidase production. In the present work, two genes encoding the subsequent steps catalysed by l-2-keto-3-deoxyrhamnonate (l-KDR) aldolase (AN9425) and l-lactaldehyde dehydrogenase (AN0554) are identified. Loss-of-function mutations cause adverse growth effects on l-rhamnose. Akin to genes lraA-C and those encoding rhamnosidases (rhaA, rhaE), their expression is induced on l-rhamnose via the transcriptional activator RhaR. Interestingly, the aldolase belongs to the ftablamily of bacterial l-KDR aldolases (PF03328/COG3836) and not that of yeasts (PF00701/COG0329). In addition, AN0554 corresponds to the previously characterized aldA gene (encodes aldehyde dehydrogenase involved in ethanol utilization) thus revealing a previously unknown role for this gene in the catabolism of l-rhamnose.

Catabolism of L-rhamnose in A. nidulans proceeds via the non-phosphorylated pathway and is glucose repressed by a CreA-independent mechanism.

L-rhamnose (6-deoxy-mannose) occurs in nature mainly as a component of certain plant structural polysaccharides and bioactive metabolites but has also been found in some microorganisms and animals. The release of L-rhamnose from these substrates is catalysed by extracellular enzymes including α-L-rhamnosidases, the production of which is induced in its presence. The free sugar enters cells via specific uptake systems where it can be metabolized. Of two L-rhamnose catabolic pathways currently known in microorganisms a non-phosphorylated pathway has been identified in fungi and some bacteria but little is known of the regulatory mechanisms governing it in fungi. In this study two genes (lraA and lraB) are predicted to be involved in the catabolism of L-rhamnose, along with lraC, in the filamentous fungus Aspergillus nidulans. Transcription of all three is co-regulated with that of the genes encoding α-L-rhamnosidases, i.e. induction mediated by the L-rhamnose-responsive transcription factor RhaR and repression of induction in the presence of glucose via a CreA-independent mechanism. The participation of lraA/AN4186 (encoding L-rhamnose dehydrogenase) in L-rhamnose catabolism was revealed by the phenotypes of knock-out mutants and their complemented strains. lraA deletion negatively affects both growth on L-rhamnose and the synthesis of α-L-rhamnosidases, indicating not only the indispensability of this pathway for L-rhamnose utilization but also that a metabolite derived from this sugar is the true physiological inducer.

Advancing Veterinary Medical Education Worldwide: Where Do We Go From Here?

Veterinary medicine is a global public good. A robust system of both public and private veterinary services is essential to protect animal health. Improved animal health leads to global food security and reduces poverty by increasing productivity, controlling transboundary diseases and expanding access to international markets. The quality of veterinary services is directly related to the quality of veterinary medical education, therefore, it is incumbent upon the entire global veterinary medical profession to support programs that improve education around the world.

Association of American Veterinary Medical Colleges (AAVMC): 50 Years of History and Service.

The mission of the Association of American Veterinary Medical Colleges (AAVMC) is to advance the quality of academic veterinary medicine. Founded in 1966 by the 18 US colleges of veterinary medicine and 3 Canadian colleges of veterinary medicine then in existence, the AAVMC is celebrating 50 years of public service. Initially, the AAVMC comprised the Council of Deans, the Council of Educators, and the Council of Chairs. In 1984, the tri-cameral structure was abandoned and a new governing structure with a board of directors was created. In 1997, the AAVMC was incorporated in Washington, DC and a common application service was created. Matters such as workforce issues and the cost of veterinary medical education have persisted for decades. The AAVMC is a champion of diversity in the veterinary profession and a strong advocate for One Health. The AAVMC has adopted a global perspective as more international colleges of veterinary medicine have earned COE accreditation and become members.

The Loss-of-Function Mutation aldA67 Leads to Enhanced α-L-Rhamnosidase Production by Aspergillus nidulans.

In Aspergillus nidulans L-rhamnose is catabolised to pyruvate and L-lactaldehyde, and the latter ultimately to L-lactate, via the non-phosphorylated pathway (LRA) encoded by the genes lraA-D, and aldA that encodes a broad substrate range aldehyde dehydrogenase (ALDH) that also functions in ethanol utilisation. LRA pathway expression requires both the pathway-specific transcriptional activator RhaR (rhaR is expressed constitutively) and the presence of L-rhamnose. The deletion of lraA severely impairs growth when L-rhamnose is the sole source of carbon and in addition it abolishes the induction of genes that respond to L-rhamnose/RhaR, indicating that an intermediate of the LRA pathway is the physiological inducer likely required to activate RhaR. The loss-of-function mutation aldA67 also has a severe negative impact on growth on L-rhamnose but, in contrast to the deletion of lraA, the expression levels of L-rhamnose/RhaR-responsive genes under inducing conditions are substantially up-regulated and the production of α-L-rhamnosidase activity is greatly increased compared to the aldA+ control. These findings are consistent with accumulation of the physiological inducer as a consequence of the loss of ALDH activity. Our observations suggest that aldA loss-of-function mutants could be biotechnologically relevant candidates for the over-production of α-L-rhamnosidase activity or the expression of heterologous genes driven by RhaR-responsive promoters.

Agrobacterium tumefaciens-Mediated Transformation of NHEJ Mutant Aspergillus nidulans Conidia: An Efficient Tool for Targeted Gene Recombination Using Selectable Nutritional Markers.

Protoplast transformation for the introduction of recombinant DNA into Aspergillus nidulans is technically demanding and dependant on the availability and batch variability of commercial enzyme preparations. Given the success of Agrobacterium tumefaciens-mediated transformation (ATMT) in diverse pathogenic fungi, we have adapted this method to facilitate transformation of A. nidulans. Using suitably engineered binary vectors, gene-targeted ATMT of A. nidulans non-homologous end-joining (NHEJ) mutant conidia has been carried out for the first time by complementation of a nutritional requirement (uridine/uracil auxotrophy). Site-specific integration in the ΔnkuA host genome occurred at high efficiency. Unlike other transformation techniques, however, cross-feeding of certain nutritional requirements from the bacterium to the fungus was found to occur, thus limiting the choice of auxotrophies available for ATMT. In complementation tests and also for comparative purposes, integration of recombinant cassettes at a specific locus could provide a means to reduce the influence of position effects (chromatin structure) on transgene expression. In this regard, targeted disruption of the wA locus permitted visual identification of transformants carrying site-specific integration events by conidial colour (white), even when auxotrophy selection was compromised due to cross-feeding. The protocol described offers an attractive alternative to the protoplast procedure for obtaining locus-targeted A. nidulans transformants.

The 2008 update of the Aspergillus nidulans genome annotation: a community effort.

The identification and annotation of protein-coding genes is one of the primary goals of whole-genome sequencing projects, and the accuracy of predicting the primary protein products of gene expression is vital to the interpretation of the available data and the design of downstream functional applications. Nevertheless, the comprehensive annotation of eukaryotic genomes remains a considerable challenge. Many genomes submitted to public databases, including those of major model organisms, contain significant numbers of wrong and incomplete gene predictions. We present a community-based reannotation of the Aspergillus nidulans genome with the primary goal of increasing the number and quality of protein functional assignments through the careful review of experts in the field of fungal biology.

AcpA, a member of the GPR1/FUN34/YaaH membrane protein family, is essential for acetate permease activity in the hyphal fungus Aspergillus nidulans.

In a previous study, alcS, a gene of the Aspergillus nidulans alc cluster, was shown to encode a protein that belongs to the GPR1/FUN34/YaaH membrane protein family. BLAST screening of the A. nidulans genome data identified additional genes encoding hypothetical proteins that could belong to this family. In this study we report the functional characterization of one of them, AN5226. Its expression is induced by ethanol and ethyl acetate (two inducers of the alc genes) and is mediated by the specific transcriptional activator of genes of the acetate-utilization pathway FacB. Growth of a null mutant (DeltaAN5226) is notably affected when acetate is used as sole carbon source at low concentration and in a high pH medium, i.e. when protonated acetate, the form that can enter the cell by passive diffusion, is present in low amounts. Consistently, expression of AN5226 is also induced by acetate, but only when the latter is present at low concentrations. (14)C-labelled acetate uptake experiments using germinating conidia demonstrate an essential role for AN5226 in mediated acetate transport. To our knowledge this report is the first to provide evidence for the identification of an acetate transporter in filamentous fungi. We have designated AN5226 as acpA (for acetate permease A).

The need for public-health veterinarians as seen by future employers.

Future employers of veterinarians working in public health see a fast-growing demand. Emerging zoonotic diseases, bio-security threats, and food-safety problems all require the expertise of veterinarians with a focus on complex, global problems that span both human and animal health. The Public Health Task Force of the Association of American Veterinary Medical Colleges convened a group of stakeholders representing various branches of the US federal government, state and local governments, and professional societies to discuss their needs for public-health veterinarians. This article discusses those needs, the broader societal needs that require veterinarians with public-health expertise, and the implications of these for educational programs to train DVMs in public-health issues.

The critical need for federal legislation to provide for the expansion of the veterinary workforce.

American veterinary medical education stands at a crucial point. To maintain the status quo and to meet ever-increasing societal needs within the United States and globally, it is essential that the veterinary medical profession expand its horizons and capabilities. If it does not, it will lose its current status. The profession faces a crucial shortage in the workforce it needs both to continue to perform its current functions and, more importantly, to meet its growing responsibilities. This is not a new situation, and the profession can learn from its past successes and failures. Action is necessary. The profession has the capability and expertise to meet these challenges, but it must activate these skills in order to succeed.

End of veterinary school as we know it.

Disruptive innovation will transform veterinary education in the next 10 years, predicts Andrew Maccabe.

Veterinary medical education for modern food systems: past, present, and brainstorming a future.

Concepts presented here were derived from breakout sessions constituted by the 90 attendees of the Veterinary Medical Education for Modern Food Systems symposium, held in Kansas City, Missouri, USA, in October 2005. The attendees were food-animal educators, veterinary faculty, college deans and administrators, and veterinarians employed in government, industry, and private practice. Discussions at these breakout sessions focused on four primary areas: (1) determining the data needed to document the current demand for food-supply veterinarians (FSVs); (2) defining the information/skills/abilities needed within veterinary school curricula to address the current demands on FSVs; (3) outlining pre-DVM educational requirements needed to support FSVs; and (4) considering the role of post-DVM programs in meeting the demand for FSVs.

Aspergillus niger mstA encodes a high-affinity sugar/H+ symporter which is regulated in response to extracellular pH.

A sugar-transporter-encoding gene, mstA, which is a member of the major facilitator superfamily, has been cloned from a genomic DNA library of the filamentous fungus Aspergillus niger. To enable the functional characterization of MSTA, a full-length cDNA was expressed in a Saccharomyces cerevisiae strain deficient in hexose uptake. Uptake experiments using 14C-labelled monosaccharides demonstrated that although able to transport D-fructose ( K(m), 4.5+/-1.0 mM), D-xylose ( K(m), 0.3+/-0.1 mM) and D-mannose ( K(m), 60+/-20 microM), MSTA has a preference for D-glucose (K(m), 25+/-10 microM). pH changes associated with sugar transport indicate that MSTA catalyses monosaccharide/H+ symport. Expression of mstA in response to carbon starvation and upon transfer to poor carbon sources is consistent with a role for MSTA as a high-affinity transporter for D-glucose, D-mannose and D-xylose. Northern analysis has shown that mstA is subject to CreA-mediated carbon catabolite repression and pH regulation mediated by PacC. A. niger strains in which the mstA gene had been disrupted are phenotypically identical with isogenic reference strains when grown on 0.1-60 mM D-glucose, D-mannose, D-fructose or D-xylose. This indicates that A. niger possesses other transporters capable of compensating for the absence of MSTA.

Writing Across the Curriculum: using Healthy People 2010 and the DHHS Secretary's Award for Innovations in Health Promotion and Disease Prevention.

The authors detail a Writing Across the Curriculum (WAC) exercise that combines the Department of Health and Human Services' Secretary's Award for Innovations in Health Promotion and Disease Prevention (Secretary's Award) and the DHHS document Healthy People 2010. The authors discuss the writing competition as a way to encourage innovative problem solving and provide curricular instructions for using Healthy People 2010 and the Secretary's Award as a WAC exercise.

Skills, knowledge, aptitudes, and attitudes colloquium.

Three projects recently funded by the American Veterinary Medical Association (AVMA) through the National Commission on Veterinary Economic Issues (NCVEI) focused on the veterinary school applicant pool, leadership skills in the veterinary profession, and a veterinary teaching hospital business model, respectively. The Skills, Knowledge, Aptitude, and Attitude (SKAs) Colloquium was designed to present the results of these three projects, to discuss their importance for the future of the veterinary profession, and to develop action plans accordingly. In all, 24 veterinary colleges were represented at the workshop and a total of 72 attendees participated, achieving a broad representation of the veterinary profession ( both academic and non-academic). Through an orchestrated combination of general sessions and facilitated small group discussions, recommendations for implementation and initial action plans for next steps were developed. From these, a list of potential AAVMC follow-up activities was developed, including advocating and facilitating programs across schools to engage and educate faculty regarding the results of these projects; developing realistic information on careers in veterinary medicine; organizing an AAVMC leadership consortium; working toward further development and implementation of the veterinary teaching hospital (VTH) business model; coordinating and sponsoring a national forum on the future of the VTH; reviewing admissions processes; integrating leadership into veterinary curricula; and organizing opportunities for faculty development in leadership.

High-affinity glucose transport in Aspergillus nidulans is mediated by the products of two related but differentially expressed genes.

Independent systems of high and low affinity effect glucose uptake in the filamentous fungus Aspergillus nidulans. Low-affinity uptake is known to be mediated by the product of the mstE gene. In the current work two genes, mstA and mstC, have been identified that encode high-affinity glucose transporter proteins. These proteins' primary structures share over 90% similarity, indicating that the corresponding genes share a common origin. Whilst the function of the paralogous proteins is little changed, they differ notably in their patterns of expression. The mstC gene is expressed during the early phases of germination and is subject to CreA-mediated carbon catabolite repression whereas mstA is expressed as a culture tends toward carbon starvation. In addition, various pieces of genetic evidence strongly support allelism of mstC and the previously described locus sorA. Overall, our data define MstC/SorA as a high-affinity glucose transporter expressed in germinating conidia, and MstA as a high-affinity glucose transporter that operates in vegetative hyphae under conditions of carbon limitation.