Infections caused by H. pylori are associated with multiple gastrointestinal diseases. To effectively reduce disease-related morbidity is to ensure the absolute eradication of the organism. The stomach plays a vital role in endowing survival strategies to H. pylori by inducing stress-hardening and cross-resistance, which helps them resist the acidic gastric ecosystem and administered antibiotics, respectively. An unstable gastric pH can cause phenotypic alteration, which induces a non-proliferative state in the bacteria, makes them refractory to antibiotics.

Etheostoma is a genus of North American darter fish whose species have similar habitats and breeding seasons, yet hybridization is rare. Behavioral barriers have been demonstrated to play a key role in maintaining species boundaries. Further, conspecific (same species) sperm precedence has also been observed when the gametes of two different species come into contact. In this study, we investigated if physical characteristics of sperm could be a mechanism for the lower fertilization success of heterospecific (different species) males when eggs are simultaneously exposed to conspecific and heterospecific sperm. We chose to examine the sperm of two closely related species, E. zonale and E. barrenense.