China needs safe and effective microbicides for preventing sexual transmission of HIV

Sexually transmitted infections (STIs) are diseases transmitted primarily through unsafe sexual interactions. Bacteria, viruses, or parasites cause them and can result in severe health complications if untreated.ChlamydiaThe bacterium Chlamydia trachomatis is responsible for the disease Chlamydia, the most common STI in the United States. This peculiar pathogen requires human cells to reproduce, residing intracellularly. The initial infection often goes unnoticed because it typically does not...

Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...

Trichomonas vaginalis is a flagellated protozoan parasite and the causative agent of trichomoniasis, one of the most prevalent non-viral sexually transmitted infections in the United States. This extracellular parasite primarily colonizes the lower genitourinary tract in women—particularly the vagina—and in men, the urethra and prostate. Its structural and functional adaptations enable its survival, motility, and pathogenicity within the host environment.Structural Features and Host EntryT.

As part of their replication cycle, certain viruses synthesize long precursor proteins called polyproteins within infected host cells. In human immunodeficiency virus (HIV), two major polyproteins are produced: Gag and Gag-Pol. The Gag polyprotein supplies the structural components of the virus, while Gag-Pol includes essential viral enzymes such as reverse transcriptase, integrase, and protease. After synthesis, these polyproteins move to the host cell membrane, where they assemble into an...

Microorganisms play a fundamental role in vaccine development, gene therapy, and therapeutic production. Their biological properties are harnessed to advance medicine and public health. Beyond immunization, microorganisms contribute to gut health, antibiotic synthesis, and genetic disease treatment.Live Attenuated and Inactivated VaccinesLive attenuated vaccines, such as the measles, mumps, and rubella (MMR) vaccine, utilize weakened forms of pathogens to closely resemble natural infections.