Quote:Abstract

A flea preserved in Dominican amber is described as Atopopsyllus cionus, n. gen., n. sp. (Atopopsyllini n. tribe, Spilopsyllinae, Pulicidae). The male specimen has two unique characters that have not been noted in previous extant or extinct fleas, thus warranting its tribal status. These characters are five-segmented maxillary palps and cerci-like organs on abdominal tergite X. Additional characters are the absence of ctenidia, very small eyes, a lanceolate terminal segment of the maxillary palps, legs with six notches on the dorsal margin of the tibiae, five pairs of lateral plantar bristles on the distitarsomeres, and nearly straight ungues with a wide space between the basal lobe and tarsal claw. Trypanosomes and coccobacilli in the rectum and coccobacilli on the tip of the epipharynx of the fossil are depicted and briefly characterized.

A New Genus of Fleas with Associated Microorganisms in Dominican Amber

Quote:Paleomicrobiology: a Snapshot of Ancient Microbes and Approaches to Forensic Microbiology

Amber possesses several properties that enable the preservation of ancient microorganisms (Fig. 1A and B), such as its low water activity and the presence of sugars in bacterial cell walls that may prevent cell damage during the dehydration process. The absence of water in amber makes it the ideal environment for enzyme inhibition and, thus, cell component preservation, including DNA (58). Many bacterial isolates from amber belong to the genus Bacillus, which consists of aerobic spore-formers with a genome protected from UV radiation, oxidizing agents, and depurination by several mechanisms. Spores are protected by several different layers within the bacterial cell, are located where water percentages are the lowest, and exhibit the lowest pH values within the cell. Notably, even when these factors are modified, spore DNA remains conserved. This characteristic of spores has been attributed to the action of small, acid-soluble proteins (SASPs), encoded by ssp (59). SASPs are synthesized during the late stages of spore formation and are consequently degraded when spores germinate. SAPSs are known to protect DNA by binding to and saturating the molecule. Five to ten percent of the total core proteins in Bacillus spores are SASPs, and spores lacking over 85% of these proteins are incapable of being protected from DNA-damaging agents, such as UV radiation (60). These compounds protect the DNA for extended periods.

Though it was previously assumed that the survival of ancient microbes was restricted to spore-forming bacteria, Gram-positive staphylococci and Micrococcus spp. have also been isolated from 23- to 35-million-year-old and 120-million-year-old amber, respectively (61–63). Even more unexpected was the isolation of Gram-negative bacteria resembling Brevundimonas in 25- to 40-million-year-old amber (64). The isolation of a Gram-negative, non-spore-forming bacterium suggests that microbes have an array of currently unknown mechanisms that could be involved in their long-term survival.

In the case of amber, the availability of nutrients during the initial stages of amber formation allow entrapped bacteria to utilize compounds such as succinic acid until they later enter a state of dormancy. Thus, such compounds represent potentially invaluable resources to maintain bacterial growth during short periods of adjustment. Currently, the specific molecular mechanisms by which microbes isolated from amber become dormant and are resuscitated after millions of years are being further investigated.

Quote:Culture Methods and Microscopy

Culture methods provide the advantage of isolating ancient microbes and distinguishing their metabolic capabilities. However, culturing microbes from ancient sources is a difficult task, since most microorganisms may not resuscitate in common laboratory media. Furthermore, experimental design should accommodate the growth of both expected and unexpected microorganisms based on sample type (46, 59). However difficult and seemingly unlikely, increasing numbers of attempts have successfully resuscitated microorganisms from prehistoric amber and permafrost samples (50, 64). Similar studies have pinpointed possible key genes in the resuscitation process, including those for various proteins that act as resuscitation-promoting factors (62, 80, 81).

Quote:Isolation and Characterization of Bacteria from Ancient Siberian Permafrost Sediment

In this study, we isolated and characterized bacterial strains from ancient (Neogene) permafrost sediment that was permanently frozen for 3.5 million years. The sampling site was located at Mammoth Mountain in the Aldan river valley in Central Yakutia in Eastern Siberia.

(07-16-2023, 03:24 AM)EndtheMadnessNow Wrote: I wonder what the oldest human infecting pathogen specimen ever cultured is?