Search

The fungal genus Aspergillusis of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. We have generated genome sequences for ten novel, highly diverse Aspergillusspecies and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.

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.

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.

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.

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.

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.

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 (Km, 4.5±1.0 mM), d-xylose (Km, 0.3±0.1 mM) and d-mannose (Km, 60±20 µM), MSTA has a preference for d-glucose (Km, 25±10 µM). 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.

The shoot apical meristem (SAM), initially formed during embryogenesis, gives rise to the aboveground portion of the maize (Zea mays) plant. The shootless phenotype (sml) described here is caused by disruption of SAM formation due to the synergistic interaction of mutations at two genetic loci. Seedlings must be homozygous for both sml (shootmeristemless), and the unlinked dgr (distorted growth) loci for a SAM-less phenotype to occur. Seedlings mutant only for sml are impaired in their morphogenesis to different extents, whereas the dgr mutation alone does not have a recognisable phenotype. Thus, dgr can be envisaged as being a dominant modifier of sml and the 12 (normal):3 (distorted growth):1 (shoot meristemless) segregation observed in the F(2) of the double heterozygote is the result of the interaction between the sml and dgr genes. Other segregation patterns were also observed in the F(2), suggesting instability of the dgr gene. Efforts to rescue mutant embryos by growth on media enriched with hormones have been unsuccessful so far. However, mutant roots grow normally on medium supplemented with kinetin at a concentration that suppresses wild-type root elongation, suggesting possible involvement of the mutant in the reception or transduction of the kinetin signal or transport of the hormone. The shootless mutant appears to be a valuable tool with which to investigate the organization of the shoot meristem in monocots as well as a means to assay the origins and relationships between organs such as the scutellum, the coleoptile, and leaves that are initiated during the embryogenic process.

ACV Synthetase forms the tripeptide precursor of penicillins and cephalosporins from α-aminoadipate, cysteine, and valine. Catalytic sites for substrate carboxyl activation as adenylates, peptide bond formations, epimerization and release of the tripeptide-thioester are integrated in multifunctional enzymes of 405 to 425 kD. These have been characterized from several pro- and eukaryotic β-Iactam producers. Implications of these results for the thio-template mechanism of peptide formation are discussed, as well as the use of this multienzyme as a model system for enzymatic peptide synthesis.

Three Aspergillus nidulans endo-β-(1,4)-xylanases (X22, X24 and X34) have been produced in Saccharomyces cerevisiae laboratory strains. In fermenter cultivation, the resulting strains were able to secrete the heterologous xylanases when grown in minimal medium containing glucose as carbon source, yielding production levels between 0·5 and 1·0 U ml^-1. From such a culture, the xylanases were purified in a single chromatographic step and then physico-chemically characterised. The yeast derived enzymes had the same enzymatic and biochemical properties as the fungal xylanases (ie molecular weights, pI values, pH and temperature optima, Km Michaelis constants and pH and temperature stabilities). The heterologously produced enzymes retained maximum activity in the presence of 10% (w/v) glucose or 10% (w/v) fructose, concentrations normally found in musts. However, ethanol at 12% (v/v) caused inhibitions of 20% for X22 and X24 and 48% for X34. © 1998 Society of Chemical Industry.

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.

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