Clinical Microbiology and Yeast Congress

Yeast provides a flexible and rapid genetic system for studying cellular events. With an approximate generation time of 90 min, colonies containing millions of cells are produced after just 2 d of growth. In addition, yeast can propagate in both haploid and diploid forms, greatly facilitating genetic analysis. Like bacteria, haploid yeast cells can be mutated to produce specific nutritional requirements or auxotrophic genetic phenotypes, and recessive lethal mutations can either be maintained in haploids as conditional lethal alleles (e.g., temperature-sensitive mutants), or in heterozygotic diploids, which carry both wild-type and mutant alleles.

Nuclear RNA processing requires dynamic and intricately regulated machinery composed of multiple enzymes and their cofactors. Much progress has been made recently in describing the 3D structure of many elements of the nuclear degradation machinery and its cofactors. Similarly, the regulatory mechanisms that govern RNA processing are gradually coming into focus. Such advances invariably generate many new questions, which we highlight in this Yeast Congress 2019.

Most yeast infections are caused by a type of yeast called Candida albicans. Yeast is a fungus that normally lives in the vagina in small numbers. A vaginal yeast infection means that too many yeast cells are growing in the vagina. These infections are very common. When something happens to change the balance of these organisms, yeast can grow too much and cause symptoms. Vaginal yeast infections aren’t considered a sexually transmitted infection (STI). Sexual contact can spread it, but women who aren’t sexually active can also get them. Once you get a yeast infection, you’re also more likely to get another one.

Every cell has developed mechanisms to respond to changes in its environment and to adapt its growth and metabolism to unfavorable conditions. The unicellular eukaryote yeast has long proven as a particularly useful model system for the analysis of cellular stress responses, and the completion of the yeast genome sequence has only added to its power.

Food spoilage due to bacteria and\or yeast contamination can be a costly problem for the food industry. Recent progress in DNA analysis has enabled rapid, accurate yeast identification methods to be developed. Armed with this precision identification it is possible to predict and eliminate the source of contamination. Some yeast is psychrophilic, and so they can grow at relatively low temperatures. In fact, the fermentation of wine and beer is often carried out at temperatures near 40°F. Because some kinds are psychrophiles, they can create a spoilage problem in meat coolers and other refrigerated storage areas. Because they can grow under conditions of high salt or sugar content, they can cause the spoilage of certain foods in which bacteria would not grow. Foods produced by the bacterial fermentation process, such as pickles and sauerkraut, can also be spoiled by yeasts which interfere with the normal fermentative process. While certain yeasts are pathogenic, yeast infections are much less common than bacterial infections.  Foodborne illness continues to be an urgent issue across the globe. The epidemiology of the foodborne disease is changing. New pathogens have emerged, and some have spread worldwide. These pathogens cause millions of cases of sporadic illness and chronic diseases, as well as large and challenging outbreaks over many states and nations.

It refers to the bioremediation or biodegradation of contaminants and hazardous pollutants in the environment using yeast. The environment is under great stress due to industrialization and human interfering on the limited natural resources. Bioremediation is an increasingly popular method using microbial strains and their enzymes for degrading waste contaminants such as chlorinated pesticides or other pollutants to protect the environment from pollution. Bioremediation is based on biodegradative processes relate to microbial population dynamics in soil or water and its ability to consume xenobiotic as a carbon source.

The humanized yeast model has emerged as a powerful tool in large-scale screenings directed to target human proteins. The high degree of cellular processes conservation between the yeast Saccharomyces cerevisiae and higher eukaryotes has made this microorganism a valuable cell model to study the pathobiology of several human diseases.  The yeast target-based approach can be highly useful in the first-line screening of potentially active compounds to be tested in more complex cell models.

There are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Therefore there is the need for different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as ‘global transcription machinery engineering’ (gTME), to induce genetic variation, providing a new source of yeast genetic diversity.

Research is currently focusing on the transformation of new raw materials into biofuels. To date, yeast is the best micro-organism to produce alcoholic fermentation from simple sugars. Humans, with centuries of experience in this field in baking, wine-making or brewing, have very effective strains available to them. They are now used to make biofuels from renewable agricultural products - beet, sugar cane, molasses, and other amylase products. Research is currently focusing on the transformation of new raw materials into biofuels.

These infections are commonly called 'ringworm', but are not caused by worms. They are superficial infections of the skin, hair or nails caused by a variety of fungi which otherwise live in the soil, on animals, or sometimes only on people. Infections are spread by direct skin contact (with humans or animals), or indirectly from contaminated articles on floors or in the soil. Shared changing rooms and showers are often a source of tinea, while some infections are spread by sharing of items such as towels. People shed tiny pieces of skin all the time and if these contain a small amount of the fungus, it is able to survive in the environment and cause infection in someone else.

Fungal genetics is the study of the mechanisms of heritable information in fungi. Yeasts and filamentous fungi are extensively used as model organisms for eukaryotic genetic research, including cell cycle regulation, chromatin structure, genetic recombination, and gene regulation.

Autophagy refers to a group of processes that involve degradation of cytoplasmic components including cytosol, macromolecular complexes, and organelles, within the vacuole or the lysosome of higher eukaryotes.

Apoptosis is an evolutionally conserved cell suicide program used by an organism to selectively eliminate dangerous, superfluous, or damaged cells. The phenomenon of yeast cells undergoing apoptosis has long been controversial, in part because of doubts of whether cell suicide could constitute an evolutionary advantage for unicellular organisms.

Aging is not typically measured by time in yeast, but rather by the number of divisions an individual cell completes before it dies. An individual cell is easy to follow from birth to death because yeast divides asymmetrically by budding off new daughters. Unlike their mothers, the daughters start from scratch, having the potential for a full lifespan. Thus, individual cells are mortal, while the yeast population is immortal. The probability that a cell will continue dividing decreases exponentially as a function of the number of completed divisions. Thus, the mortality rate increases exponentially with age. However, it plateaus at older ages in similarity to what has been observed in other species. Yeasts undergo a variety of changes as they age, and some of these are clearly detrimental. In view of this, it is reasonable to speak of an aging process. In practical terms, yeast lifespan is measured by observing individual cells periodically under a microscope and removing buds with a micro-manipulator.

The awesome power of yeast genetics is partially due to the ability to quickly map a phenotype-producing gene to a region of the S. cerevisiae genome. For the past two decades S. cerevisiae has been the model system for much of molecular genetic research because the basic cellular mechanics of replication, recombination, cell division and metabolism are generally conserved between yeast and larger eukaryotes, including mammals.

These types of skin infections are caused by a parasite. These infections can spread beyond the skin to the bloodstream and organs. Parasitic infection isn’t life-threatening but can be uncomfortable.

These types of skin infections are caused by a fungus and are most likely to develop in damp areas of the body, such as the feet or armpit. Some fungal infections aren’t contagious, and these infections are typically non-life-threatening.

Viral skin infections are caused by a virus. These infections range from mild to severe. Different types of viral infections include

Bacterial skin infections often begin as small, red bumps that slowly increase in size. Some bacterial infections are mild and easily treated with topical antibiotics, but other infections require an oral antibiotic. Different types of bacterial skin infections include