Possible poriferan body fossils in early Neoproterozoic microbial reefs

Abstract

Molecular phylogeny indicates that metazoans (animals) emerged early in the Neoproterozoic era1, but physical evidence is lacking. The search for animal fossils from the Proterozoic eon is hampered by uncertainty about what physical characteristics to expect. Sponges are the most basic known animal type2,3; it is possible that body fossils of hitherto-undiscovered Proterozoic metazoans might resemble aspect(s) of Phanerozoic fossil sponges. Vermiform microstructure4,5, a complex petrographic feature in Phanerozoic reefal and microbial carbonates, is now known to be the body fossil of nonspicular keratosan demosponges6–10. This Article presents petrographically identical vermiform microstructure from approximately 890-million-year-old reefs. The millimetric-to-centimetric vermiform-microstructured organism lived only on, in and immediately beside reefs built by calcifying cyanobacteria (photosynthesizers), and occupied microniches in which these calcimicrobes could not live. If vermiform microstructure is in fact the fossilized tissue of keratose sponges, the material described here would represent the oldest body-fossil evidence of animals known to date, and would provide the first physical evidence that animals emerged before the Neoproterozoic oxygenation event and survived through the glacial episodes of the Cryogenian period.

Progress of the COVID-19 vaccine effort: viruses, vaccines and variants versus efficacy, effectiveness and escape

“…One important consideration is how rapidly and to what extent immunity wanes after vaccination. There were initially concerns that immunity would wane rapidly, but recent studies have observed sustained B cell-mediated immunity 12 months after initial infection 60 , 61 , although other components of the immune response, such as T cell responses, may wane faster 62 . However, there may still be benefits to an additional booster dose of vaccine.…”

mRNA vaccines for infectious diseases: principles, delivery and clinical translation

“…In preclinical studies, mRNA vaccines have elicited potent germinal centre reactions and T FH cell induction against SARS-CoV-2, HIV-1, Zika virus and influenza virus 128 , 200 – 202 . In humans, two doses of the Pfizer–BioNTech vaccine BNT162b2 induced strong germinal centre B cell responses for at least 12 weeks after immunization 203 . The antibody clones produced by the germinal centre B cells predominantly targeted the receptor-binding domain of the spike protein.…”

SARS-CoV-2 and regular patient treatment – from the use of rapid antigen testing up to treatment specific precaution measures

“…a) Since studies show that the anti-body level reduces over a period of time, is immunity established for vaccinated persons or persons after passing COVID-19 and how long will it prevail [ 21 ]? Are all vaccines equally effective [ 22 ]?…”

“…How often do new variants require revaccination? Can memory cells be formed that trigger a humoral immune response even after a long period of illness [ 21 ]?…”