Vectors Of Infectious Diseases Research Articles

Climate Change and Risk of Leishmaniasis in North America: Predictions from Ecological Niche Models of Vector and Reservoir Species

BackgroundClimate change is increasingly being implicated in species' range shifts throughout the world, including those of important vector and reservoir species for infectious diseases. In North America (México, United States, and Canada), leishmaniasis is a vector-borne disease that is autochthonous in México and Texas and has begun to expand its range northward. Further expansion to the north may be facilitated by climate change as more habitat becomes suitable for vector and reservoir species for leishmaniasis.Methods and FindingsThe analysis began with the construction of ecological niche models using a maximum entropy algorithm for the distribution of two sand fly vector species (Lutzomyia anthophora and L. diabolica), three confirmed rodent reservoir species (Neotoma albigula, N. floridana, and N. micropus), and one potential rodent reservoir species (N. mexicana) for leishmaniasis in northern México and the United States. As input, these models used species' occurrence records with topographic and climatic parameters as explanatory variables. Models were tested for their ability to predict correctly both a specified fraction of occurrence points set aside for this purpose and occurrence points from an independently derived data set. These models were refined to obtain predicted species' geographical distributions under increasingly strict assumptions about the ability of a species to disperse to suitable habitat and to persist in it, as modulated by its ecological suitability. Models successful at predictions were fitted to the extreme A2 and relatively conservative B2 projected climate scenarios for 2020, 2050, and 2080 using publicly available interpolated climate data from the Third Intergovernmental Panel on Climate Change Assessment Report. Further analyses included estimation of the projected human population that could potentially be exposed to leishmaniasis in 2020, 2050, and 2080 under the A2 and B2 scenarios. All confirmed vector and reservoir species will see an expansion of their potential range towards the north. Thus, leishmaniasis has the potential to expand northwards from México and the southern United States. In the eastern United States its spread is predicted to be limited by the range of L. diabolica; further west, L. anthophora may play the same role. In the east it may even reach the southern boundary of Canada. The risk of spread is greater for the A2 scenario than for the B2 scenario. Even in the latter case, with restrictive (contiguous) models for dispersal of vector and reservoir species, and limiting vector and reservoir species occupancy to only the top 10% of their potential suitable habitat, the expected number of human individuals exposed to leishmaniasis by 2080 will at least double its present value.ConclusionsThese models predict that climate change will exacerbate the ecological risk of human exposure to leishmaniasis in areas outside its present range in the United States and, possibly, in parts of southern Canada. This prediction suggests the adoption of measures such as surveillance for leishmaniasis north of Texas as disease cases spread northwards. Potential vector and reservoir control strategies—besides direct intervention in disease cases—should also be further investigated.

The stethoscope as a vector of infectious diseases in the paediatric division

The stethoscope as a vector of infectious diseases in the paediatric division

Climatic Change and Skin: Diagnostic and Therapeutic Challenges

Many scientists have reported on the current trend toward global warming and decreased precipitation. The magnitude and cause of these changes and their impact on human activity are matters of debate. Higher temperatures could increase the prevalence of some skin diseases. More people would suffer from sensitive skin and dry skin due to the reduction of relative humidity. An impaired skin barrier function would increase the severity and prevalence of atopic dermatitis. The greater percentage of UV-B radiation reaching the earth's surface, combined with the increased popularity of sunbathing, may lead to greater rates of skin cancer and photoaging if effective sunscreens are not used. Furthermore, the habitats of various vectors of infectious disease are changing. Such changes, should they occur, will be a challenge for dermatologists who will face the important task of prevention and early diagnosis and treatment of these diseases.

Viruses as vaccine vectors for infectious diseases and cancer

Recent developments in the use of viruses as vaccine vectors have been facilitated by a better understanding of viral biology. Advances occur as we gain greater insight into the interrelationship of viruses and the immune system. Viral-vector vaccines remain the best means to induce cellular immunity and are now showing promise for the induction of strong humoral responses. The potential benefits for global health that are offered by this field reflect the scope and utility of viruses as vaccine vectors for human and veterinary applications, with targets ranging from certain types of cancer to a vast array of infectious diseases.

Biodiversity Informatics: the emergence of a field

Recent years have seen great technological advances that have helped usher in a new generation of approaches to understand and share knowledge about the planet in which we live. A number of major initiatives that aim to catalyze necessary technological and biological advances synergistically have emerged globally. Of these enabling initiatives, the Encyclopedia of Life (EOL; http://www.eol.org) and the Barcode of Life (BOL; http://barcoding.si.edu) are projects that have collectively help lay a framework within which we will see the next generation of taxonomic innovation and discovery. The successes of both EOL and BOL have the potential to impact multiple facets of society - from the discovery of new species, to the development of conservation strategies for endangered life, to insights into infectious disease hosts and vectors, to the discovery of life-saving medicinal plants, to the piquing of general interest about life on Earth and our role in the complex web of life. Both the EOL and BOL initiatives are possible thanks to a number of significant advancements in knowledge discovery, integration, and management techniques. Collectively termed 'biodiversity informatics,' this new suite of methodologies and tools extends contemporary computer science and informatics principles within the context of biodiversity data. This supplement, made possible through funding from both EOL and BOL, brings forth some of the pioneering work from leading biodiversity informatics researchers. While nascent as a discipline, biodiversity informatics has proven to not only adopt, but also help significantly challenge and advance the most recent technological advances and computational approaches for managing complex data. In contrast to bioinformatics, which in primarily focused on managing relevant molecular biology data, biodiversity informatics requires frameworks and approaches that can accommodate the full range of biological information - from molecules to morphological features, to populations, to habitats - collectively developing the ultimate computational Web of knowledge about life on Earth. This supplement starts with a piece from Chavan and Ingwersen that goes through some of the fundamental principles for disseminating biodiversity information, discussing both the hindrances and opportunities [1]. Hill et al. then describe how one might leverage existing technological infrastructure for enabling georeferencing of biodiversity data [2]. Demonstrating how biodiversity informatics can often benefit from the latest advances in searching strategies, Hajibabaei and Singer describe an approach for making use of Google to identify relevant information with respect to DNA sequences [3]. Next, Page discusses the nuances of biological global unique identifiers, which may be necessary to link relevant biodiversity data across various spheres of knowledge [4]. In consideration of the necessary continual curation required for disparate biodiversity knowledge, Smith et al. describe a Drupal-based technology called Scratchpads for managing and sharing biodiversity knowledge [5]. In parallel to the emerging infrastructure for managing and disseminating biodiversity information, DNA Barcode analysis methods represent a crucial entry point into the realm of biodiversity knowledge. The last four articles thus focus on some recent advances in DNA Barcoding analytic approaches. The first of these articles, from Bertolazzi et al., presents a machine learning approach for classifying species according to DNA Barcode derived information [6]. Chu et al. then describe a 'composition vector' approach for making use of large datasets of DNA Barcodes for classification [7]. In light of molecular sequence alignment as an often rate-limiting step in many classification approaches, Kuksa and Pavlovic present an alignment-free approach for DNA Barcode data [8]. In light of the range of approaches associated with DNA Barcode based classification, Austerlitz et al. present an overview of common phylogenetic and statistical methods most commonly considered [9]. A unifying theme in the articles of this supplement is the diversity of issues that remain to be resolved going forward. It is my hope that this issue helps continue and inspire new dialogue across the full range of disciplines associated with this burgeoning field.

The Poxvirus A35 Protein Is an Immunoregulator

It was shown previously that the highly conserved vaccinia virus A35 gene is an important virulence factor in respiratory infection of mice. We show here that A35 is also required for full virulence by the intraperitoneal route of infection. A virus mutant in which the A35 gene has been removed replicated normally and elicited improved antibody, gamma interferon-secreting cell, and cytotoxic T-lymphocyte responses compared to wild-type virus, suggesting that A35 increases poxvirus virulence by immunomodulation. The enhanced immune response correlated with an improved control of viral titers in target organs after the development of the specific immune response. Finally, the A35 deletion mutant virus also provided protection from lethal challenge (1,000 50% lethal doses) equal to that of the wild-type virus. Together, these data suggest that A35 deletion viruses will make safer and more efficacious vaccines for poxviruses. In addition, the A35 deletion viruses will serve as improved platform vectors for other infectious diseases and cancer and will be superior vaccine choices for postexposure poxvirus vaccination, as they also provide improved kinetics of the immune response.

Space-based technologies and high performance computing in support of environmental sustainability in developing countries

Inspired by recent service on the User Working Group for NASA’s Socio-Economic Data Applications Center (SEDAC), the Science Review Panel for the Arctic Region Supercomputer Center, the Technology Advisory Committee for South Africa’s Center for High Performance Computing and participation in the NATO Pilot Study on Clean Products and Processes over the past four years, our distributed interdisciplinary research collaborators intensified our efforts to address some of the fundamental issues with respect to societal sustainability. We particularly focused on highly vulnerable communities, at risk for an array of immediate and long-term biogenic and anthropogenic disasters. Specifically, we sought to address the question: ‘‘How should state-of-the-science computational capabilities and earth observing satellites be optimally placed in the service of environmental sustainability and sustainable development?’’ In the on-going process of examining this issue, it has been encouraging to observe the technological progress that has recently occurred within Latin America, Asia and Africa. CONAE http://www.conae.gov.ar/eng/aplicaciones/ salud_new.html, the Argentine Space Agency’s SAC-C satellite has been operational since 2000 and its successor, Aquarius (SAC-D) will be launched in 2010; while SABIA (SAC-E), the Argentine-Brazilian Satellite for Information on Food, Water and the Environment, ALSAT-2 (SAC-F) and SAOCOM 1-A, with microwave radar and a thermal infrared camera, are each currently under production. Brazil’s other collaboration with China, the ChineseBrazilian Earth Resources Satellite (CBERS) has been generously offered without licensure fees to developing countries. China, as well, freely offers its Fung Yun 1D MVISR globally to receiving stations. Robust earth observing satellite launch schedules are apparent in China, India, Japan, Korea, Taiwan and Thailand. African engagement in satellite remote sensing has been actively promoted by the African Association for Remote Sensing of Environment (AARSE) and by the 2009 IEEE International Geo-science & Remote Sensing Symposium (IGARSS) held in Cape Town, South Africa. As a follow-on to the NATO Committee on the Challenges to Modern Society’s Pilot Study on Clean Products & Processes, the NATO Science for Peace Program has awarded funding to establish the Kamal Ewida Earth Observatory http://www.itap.purdue.edu/pto/NATO_KEEO/ index_en.html, which will include real-time satellite ground stations in Egypt at Cairo University and Al Azhar University, primarily for early warning and mitigation of disasters, including storms, flooding and epidemics, through identifying and monitoring infectious disease vector habitat, as well as for facilitating natural resource management. This initiative is in collaboration with the Kandilli Observatory and Earthquake Research Institute at Bogazici University in Istanbul, Turkey and with the Purdue Terrestrial Observatory at Purdue University’s Rosen Center for Advanced Computing in West Lafayette, Indiana, USA. Analysis of the real-time satellite data will benefit from a recently installed IBM Blue Gene L Supercomputer at Egypt’s National Authority for Remote Sensing & Space Sciences (NARSS), which has the capability to produce data products in near-real-time, as input to decision support for time-critical events. The other civilian supercomputer facility on the African continent is at South G. L. Rochon (&) Purdue Terrestrial Observatory (PTO), Information Technology at Purdue (ITaP), Rosen Center for Advanced Computing (RCAC), Purdue University, 203 Martin Jischke Drive, Mann Hall 160, West Lafayette, IN 47907, USA e-mail: rochon@purdue.edu

Hosts as ecological traps for the vector of Lyme disease.

Vectors of infectious diseases are generally thought to be regulated by abiotic conditions such as climate or the availability of specific hosts or habitats. In this study we tested whether blacklegged ticks, the vectors of Lyme disease, granulocytic anaplasmosis and babesiosis can be regulated by the species of vertebrate hosts on which they obligately feed. By subjecting field-caught hosts to parasitism by larval blacklegged ticks, we found that some host species (e.g. opossums, squirrels) that are abundantly parasitized in nature kill 83-96% of the ticks that attempt to attach and feed, while other species are more permissive of tick feeding. Given natural tick burdens we document on these hosts, we show that some hosts can kill thousands of ticks per hectare. These results indicate that the abundance of tick vectors can be regulated by the identity of the hosts upon which these vectors feed. By simulating the removal of hosts from intact communities using empirical models, we show that the loss of biodiversity may exacerbate disease risk by increasing both vector numbers and vector infection rates with a zoonotic pathogen.

“Can religious icons be vectors of infectious diseases in hospital settings?”

According to Jewish tradition, Mezuzahs should be affixed on all doorposts leading to communal places. We evaluated the bacterial pathogenic load on the Mezuzah covers in our hospital. Mezuzahs were sampled in all hospital departments, and cultures were carried out. Serving as a control group, door handles belonging to the same departments were tested as well. Most samples harbored potential pathogens. Few cultures were positive in the control group, demonstrating that regular disinfection is carried out, but apparently religious artifacts are overlooked.

Identification and isolation of cDNA clones encoding the abundant secreted proteins in the saliva proteome ofCulicoides nubeculosus

Culicoides spp. are vectors of several infectious diseases of veterinary importance and a major cause of allergy in horses and other livestock. Their saliva contains a number of proteins which enable blood feeding, enhance disease transmission and act as allergens. We report the construction of a novel cDNA library from Culicoides nubeculosus linked to the analysis of abundant salivary gland proteins by mass spectrometry. Fifty-four novel proteins sequences are described including those of the enzymes maltase, hyaluronidase and two serine proteases demonstrated to be present in Culicoides salivary glands, as well as several members of the D7 family and protease inhibitors with putative anticoagulant activity. In addition, several families of abundant proteins with unknown function were identified including some of the major candidate allergens that cause insect bite hypersensitivity in horses.

From Tucson to Genomics and Transgenics: The Vector Biology Network and the Emergence of Modern Vector Biology

From Tucson to Genomics and Transgenics: The Vector Biology Network and the Emergence of Modern Vector Biology

Development and characterization of 12 polymorphic microsatellite loci in the American dog tick (Dermacentor variabilis)

Twelve polymorphic microsatellite loci were developed for the American dog tick (Dermacentor variabilis), an important vector of infectious diseases in humans and animals. Four multiplexed panels comprising the loci were developed and 45 ticks collected from two raccoons (Procyon lotor) were genotyped. The number of alleles per locus ranged from nine to 30, and single locus heterozygosities ranged from 0.18 to 0.93. Data generated using these markers will further our understanding of factors affecting gene flow in D. variabilis, thus helping to elucidate the transmission dynamics of diseases associated with this vector.

The stethoscope as a vector of infectious diseases in the paediatric division

Nosocomial infections are of great concern in hospital settings, and even more so in the paediatric ward. Health professionals and their medical equipment have long been known to act as vectors of infectious diseases. This study aimed at evaluating the presence of bacterial pathogens on the stethoscopes of medical personnel in the paediatric division. Forty-three stethoscopes belonging to senior physicians, residents, interns and medical students at the paediatric ward were sampled. Bacterial cultures and antibiotic sensitivity testing were carried out. All but six bacterial cultures were positive (85.7%). Staphylococcal species were the most common contaminants (47.5%). One case of methicillin-resistant Staphylococcus aureus was encountered. Gram-negative organisms were isolated in nine different samples (21%) including one case of Acinetobacter baumannii in the neonatal intensive care unit. Most stethoscopes harbour potential pathogens. The isolation of Gram-negative organisms pose a real risk of spreading potentially serious infections, especially in the setting of intensive care departments. Apparently, the current recommendations of regular disinfection of stethoscopes are not carried out by health personnel that participated in the study.

The phenology and population dynamics of Culicoides spp. in different ecosystems in The Netherlands

The Netherlands has enjoyed a relatively free state of vector-borne diseases of economic importance for more than one century. Emerging infectious diseases may change this situation, threatening the health of humans, domestic livestock and wildlife. In order to be prepared for the potential outbreak of vector-borne diseases, a study was undertaken to investigate the distribution and seasonal dynamics of candidate vectors of infectious diseases with emphasis on bluetongue vectors ( Culicoides spp.). The study focused primarily on the relationship between characteristic ecosystems suitable for bluetongue vectors and climate, as well as on the phenology and population dynamics of these vectors. Twelve locations were selected, distributed over four distinct habitats: a wetland area, three riverine systems, four peat land areas and four livestock farms. Culicoides populations were sampled continuously using CO 2-baited counterflow traps from July 2005 until August 2006, with an interruption from November 2005 to March 2006. All vectors were identified to species level. Meteorological and environmental data were collected at each location. Culicoides species were found in all four different habitat types studied. Wetland areas and peat bogs were rich in Culicoides spp. The taxonomic groups Culicoides obsoletus (Meigen) and Culicoides pulicaris (Linnaeus) were strongly associated with farms. Eighty-eight percent of all Culicoides consisted of the taxon C. obsoletus/ Culicoides scoticus. On the livestock farms, 3% of Culicoides existed of the alleged bluetongue vector Culicoides dewulfi Goetghebuer. Culicoides impunctatus Goetghebuer was strongly associated with wetland and peat bog. Many Culicoides species were found until late in the phenological season and their activity was strongly associated with climate throughout the year. High annual variations in population dynamics were observed within the same study areas, which were probably caused by annual variations in environmental conditions. The study demonstrates that candidate vectors of bluetongue virus are present in natural and livestock-farm habitats in the Netherlands, distributed widely across the country. Under favourable climatic conditions, following virus introduction, bluetongue can spread among livestock (cattle, sheep and goats), depending on the nature of the viral serotype. The question now arises whether the virus can survive the winter conditions in north-western Europe and whether measures can be taken that effectively halt further spread of the disease.

Adenovirus-vectored vaccines

Background: Engineered adenoviruses are being increasingly explored as immunoprophylactic or immunotherapeutic vaccine vectors. Encouraging data from preclinical studies using human adenovirus vectors carrying different antigen genes have resulted in many currently ongoing clinical trials. Objective: The article seeks to review the current status of the use of adenoviruses as vaccine vectors. Methods: This review is based on the patent literature since 2000 pertaining to the development of adenovirus vaccine vectors for infectious and non-infectious diseases. Conclusion: Human adenovirus-vectored vaccines have important limitations that stem from their immunogenicity and restrict their utility. This has spurred intensive efforts to find alternative adenovirus vectors and strategies, each with its own advantages and shortcomings.

Current status of ticks in Asia

Ticks and tick-borne diseases (TTBD) pose a major constraint for the development and improvement of the livestock industry. They cause economical losses by decreasing milk production, effecting weight loss, and increasing risk for bacterial, viral, and fungal infections. It has been reported that 80% of 1,200 million cattle are at risk for TTBDs causing a global annual loss of US$7,000 million. Ticks are currently considered to be second only to mosquitoes as vectors of human infectious diseases in the world. There are more than 850 species recognized with approximately 180 in the family Argasidae (soft ticks) and the others in the family Ixodidae (hard ticks). In Asia, the economical losses due to TTBDs is great; however, the knowledge on Asian ticks is scarce and needs intensive studies regarding their geographical distribution, ecology, and diseases transmission. To close this gap, the Asian component of the Integrated Consortium on Ticks and Tick-Borne Diseases (ICTTD-3) organized a meeting held from 26th-28th April 2006 in Pendik, Istanbul, Turkey on the characterization of Asian ticks. Besides the knowledge dissemination, this meeting resulted in a number of achievements such as the establishment of working groups for epidemiological studies and distribution of tick differentiation protocols and diagnostic tools.

How and Why Does a Fly Turn Its Immune System Off?

With its powerful genetics and rapid generation time, the fruit fly, Drosophila, provides crucial insights into the evolution and conservation of fundamental immune mechanisms. The best example of molecules discovered in the fly that are shared in human immunity operate in the Toll signaling pathway, one of first lines of defense against pathogens. Drosophila can also benefit human health by providing a model for immune systems of arthropod vectors of infectious disease. Additionally, from a comparative immunological perspective, it is useful to know how different organisms have evolved solutions for fighting infections, because this information can lead to new ways of thinking about disease. At a simple level, it is clear that many immune responses are designed to turn on when needed, presumably because their constitutive expression would be deleterious. After induction, immune responses must also be turned off, for the same reason they are not left on from birth. The resolution of inflammation in humans occurs through a complex active signaling program [1]. This negative regulation is important because excessive inflammation leads to pathology and death. The fly served as a good model for the induction of an innate immune response, pointing to conserved pathways and mechanisms. Recent work shows that the fly's immune response is more subtly regulated and produces a wider range of responses than was thought possible even just a few years ago. Specifically, this new work shows that the fly immune response is edited and repressed. These newly discovered systems provide us with an opportunity to study both immune signaling and the pathology that can result from unregulated immune responses, and they promise to teach us about mechanisms that might be translated back to human health.

Antibody response against saliva antigens of Anopheles gambiae and Aedes aegypti in travellers in tropical Africa

Exposure to vectors of infectious diseases has been associated with antibody responses against salivary antigens of arthropods among people living in endemic areas. This immune response has been proposed as a surrogate marker of exposure to vectors appropriate for evaluating the protective efficacy of antivectorial devices. The existence and potential use of such antibody responses in travellers transiently exposed to Plasmodium or arbovirus vectors in tropical areas has never been investigated. The IgM and IgG antibody responses of 88 French soldiers against the saliva of Anopheles gambiae and Aedes aegypti were evaluated before and after a 5-month journey in tropical Africa. Antibody responses against Anopheles and Aedes saliva increased significantly in 41% and 15% of the individuals, respectively, and appeared to be specific to the mosquito genus. A proteomic and immunoproteomic analysis of anopheles and Aedes saliva allowed for the identification of some antigens that were recognized by most of the exposed individuals. These results suggest that antibody responses to the saliva of mosquitoes could be considered as specific surrogate markers of exposure of travellers to mosquito vectors that transmit arthropod borne infections.

Antibiotic Treatment of the Tick Vector Amblyomma americanum Reduced Reproductive Fitness

BackgroundThe lone star tick Amblyomma americanum is a common pest and vector of infectious diseases for humans and other mammals in the southern and eastern United States. A Coxiella sp. bacterial endosymbiont was highly prevalent in both laboratory-reared and field-collected A. americanum. The Coxiella sp. was demonstrated in all stages of tick and in greatest densities in nymphs and adult females, while a Rickettsia sp. was less prevalent and in lower densities when present.Methodology/Principal FindingsWe manipulated the numbers of both bacterial species in laboratory-reared A. americanum by injecting engorged nymphs or engorged, mated females with single doses of an antibiotic (rifampin or tetracycline) or buffer alone. Burdens of the bacteria after molting or after oviposition were estimated by quantitative polymerase chain reaction with primers and probes specific for each bacterial species or, as an internal standard, the host tick. Post-molt adult ticks that had been treated with rifampin or tetracycline had lower numbers of the Coxiella sp. and Rickettsia sp. and generally weighed less than ticks that received buffer alone. Similarly, after oviposition, females treated previously with either antibiotic had lower burdens of both bacterial species in comparison to controls. Treatment of engorged females with either antibiotic was associated with prolonged time to oviposition, lower proportions of ticks that hatched, lower proportions of viable larvae among total larvae, and lower numbers of viable larvae per tick. These fitness estimators were associated with reduced numbers of the Coxiella sp. but not the Rickettsia sp.Conclusion/SignificanceThe findings indicate that the Coxiella sp. is a primary endosymbiont, perhaps provisioning the obligately hematophagous parasites with essential nutrients. The results also suggest that antibiotics could be incorporated into an integrated pest management plan for control of these and other tick vectors of disease.

Allozyme polymorphism of Mdh and α-Gpdh in Ixodes ricinus populations: comparison of borreliae-infected and uninfected ticks

Ixodes ricinus Linnaeus (Acari: Ixodidae) ticks are vectors of numerous infectious diseases in humans and animals. The allozyme variability of MDH and alpha-Gpdh was detected by native polyacrylamide gel electrophoresis in I. ricinus natural populations in three localities in Serbia. Four alleles of Mdh locus (MDH 1, MDH 2, MDH 3 and MDH X) and four alleles of alpha-Gpdh locus (VS, S, F and VF) were detected. Interpopulation differences in Mdh and alpha-Gpdh allele frequencies were statistically insignificant. Significant difference in alpha-Gpdh allele frequencies between males and females was recorded in the largest sample only. Differences in allele frequencies, detected between borreliae-infected and uninfected I. ricinus ticks, were close to the level of statistical significance, especially for alpha-Gpdh locus. Clear significant difference appeared in females when sexes were tested separatelly (P = 0.037). It is interesting that genotypes containing rarer alleles (MDH 1 and S) were infected in higher proportion in comparison to other genotypes. Our results point towards a possible role of Mdh and alpha-Gpdh loci in I. ricinus ticks in the determination of energy requirements for host seeking. Sex differences in alpha-Gpdh allele frequencies suggest that selective pressure, concerning efficiency of reserve materials utilisation, points to alpha-Gpdh rather than to Mdh locus.