Since the 1980s, decreases in amphibian populations, including population decline and localized mass extinctions, have been observed in locations all over the world. These declines are known as one of the most critical threats to global biodiversity.
Plethodon is a genus of salamanders in the family Plethodontidae. They are also known as woodland salamanders or, more rarely, slimy salamanders. All members of the genus are endemic to North America. They have no aquatic larval stage. In some species, such as Plethodon cinereus, the red-backed salamander, eggs are laid underneath a stone or log. Young hatch in the adult form. Members of Plethodon primarily eat small invertebrates. The earliest known fossils of this genus are from the Hemphillian of Tennessee in the United States.
The red-backed salamander is a small, hardy woodland salamander species in the family Plethodontidae. It is also known as the redback salamander, eastern red-backed salamander, or the northern red-backed salamander to distinguish it from the southern red-backed salamander. The species inhabits wooded slopes in eastern North America, west to Missouri, south to North Carolina, and north from southern Quebec and the Maritime provinces in Canada to Minnesota. It is one of 56 species in the genus Plethodon. Red-backed salamanders are notable for their color polymorphism and primarily display two color morph varieties, which differ in physiology and anti-predator behavior.
Chytridiomycosis is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. Chytridiomycosis has been linked to dramatic population declines or extinctions of amphibian species in western North America, Central America, South America, eastern Australia, east Africa (Tanzania), and Dominica and Montserrat in the Caribbean. Much of the New World is also at risk of the disease arriving within the coming years. The fungus is capable of causing sporadic deaths in some amphibian populations and 100% mortality in others. No effective measure is known for control of the disease in wild populations. Various clinical signs are seen by individuals affected by the disease. A number of options are possible for controlling this disease-causing fungus, though none has proved to be feasible on a large scale. The disease has been proposed as a contributing factor to a global decline in amphibian populations that apparently has affected about 30% of the amphibian species of the world. Some research found evidence insufficient for linking chytrid fungi and chytridiomycosis to global amphibian declines, but more recent research establishes a connection and attributes the spread of the disease to its transmission through international trade routes into native ecosystems.
The boreal chorus frog is a species of chorus frog native to Canada from central Quebec to eastern British Columbia and north to the Northwest Territories and the southern portion of the Yukon. It occurs in the USA throughout Montana, northwestern Wisconsin, northeastern Arizona, northern New Mexico, and southwestern Utah.
Batrachochytrium dendrobatidis, also known as Bd or the amphibian chytrid fungus, is a fungus that causes the disease chytridiomycosis in amphibians.
Chromobacterium violaceum is a Gram-negative, facultative anaerobic, non-sporing coccobacillus. It is motile with the help of a single flagellum which is located at the pole of the coccobacillus. Usually, there are one or two more lateral flagella as well. It is part of the normal flora of water and soil of tropical and sub-tropical regions of the world. It produces a natural antibiotic called violacein, which may be useful for the treatment of colon and other cancers. It grows readily on nutrient agar, producing distinctive smooth low convex colonies with a dark violet metallic sheen. Some strains of the bacteria which do not produce this pigment have also been reported. It has the ability to break down tarballs.
The Panamanian golden frog, also known as Cerro Campana stubfoot toad and other names, is a species of toad endemic to Panama. Panamanian golden frogs inhabit the streams along the mountainous slopes of the Cordilleran cloud forests of west-central Panama. While the IUCN lists it as Critically Endangered, it may in fact have been extinct in the wild since 2007. Individuals have been collected for breeding in captivity in a bid to preserve the species. The alternative common name, Zetek's golden frog, and the epithet zeteki both commemorate the entomologist James Zetek.
Rhizophydiales are an important group of chytrid fungi. They are found in soil as well as marine and fresh water habitats where they function as parasites and decomposers.
The green-eyed treefrog is a species of Australasian treefrog in the subfamily Pelodryadinae that occurs in the Wet Tropics of Australia.
The Shenandoah salamander is a small, terrestrial salamander found exclusively in Shenandoah National Park in Virginia. The Shenandoah salamander inhabits a very small range of land on just three mountain peaks. Due to the small habitat range, interspecies competition, and climate change, the population of the Shenandoah salamander is vulnerable to extinction. Mitigating human effects on the habitat of the species will be essential in attempting to preserve and grow the population.
2,4-Diacetylphloroglucinol or Phl is a natural phenol found in several bacteria:
Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts. Prolonged breeders, the majority of frog species, have breeding seasons at regular intervals where male-male competition occurs with males arriving at the waters edge first in large number and producing a wide range of vocalizations, with variations in depth of calls the speed of calls and other complex behaviours to attract mates. The fittest males will have the deepest croaks and the best territories, with females making their mate choices at least partly based on the males depth of croaking. This has led to sexual dimorphism, with females being larger than males in 90% of species, males in 10% and males fighting for groups of females.
Batrachochytrium salamandrivorans (Bsal) is a pathogenic chytrid fungus that infects amphibian species. Although salamanders and newts seem to be the most susceptible, some anuran species are also affected. Bsal has emerged recently and poses a major threat to species in Europe and North America.
Speleomantes strinatii, the French cave salamander, North-west Italian cave salamander, or Strinati's cave salamander is a small species of salamander found in northwest Italy and southeast France. It is very similar in appearance to the Italian cave salamander, but has a paler belly.
Indole-3-carbaldehyde (I3A), also known as indole-3-aldehyde and 3-formylindole, is a metabolite of dietary L-tryptophan which is synthesized by human gastrointestinal bacteria, particularly species of the Lactobacillus genus. I3A is a biologically active metabolite which acts as a receptor agonist at the aryl hydrocarbon receptor in intestinal immune cells, in turn stimulating the production of interleukin-22 which facilitates mucosal reactivity.
Karen R. Lips is a Professor of Biology at University of Maryland, College Park. Lips' work in the 1990s eventually contributed to the identification of the chytrid fungus as the primary cause of frog decline worldwide.
Nikkomycins are a group of antifungal medications. They work by interfering with the building of the fungal cell wall which results in the fungal cell breaking open. They were discovered in 1976. The specific agent nikkomycin Z has weak activity against Aspergillus fumigatus which may be of benefit when used with other medications, such as caspofungin, ranconazole and amphotericin B, fluconazole or itraconazole. Nikkomycin Z also inhibits growth of Batrachochytrium dendrobatidis, a serious fungal pathogen linked to global amphibian declines, while lower concentrations of Nikkomycin Z enhanced natural amphibian antimicrobial skin peptide effectiveness in vitro.
