Publications by authors named "Alyssa Brokaw"
Article Synopsis
- Bacteria like Group B Streptococcus (GBS) can lead to serious issues during pregnancy, including preterm births and infections in newborns.
- GBS produces an enzyme called hyaluronidase that breaks down a component called hyaluronan in the host, which weakens the immune response and allows the bacteria to spread more easily.
- This study reveals that GBS's hyaluronidase (HylB) promotes immune suppression during pregnancy and involves specific immune receptors (TLR2, TLR4) and the cytokine IL-10, highlighting the need for better understanding to create effective treatment options.
Article Synopsis
- Hemolytic lipids, like granadaene from Group B Streptococcus (GBS), are harmful to immune cells and contribute to infections in both newborns and adults.
- Immunization with a synthetic safe version of granadaene (R-P4) has shown to enhance immune responses, leading to improved protection against GBS infections in mice.
- Key immune cells, particularly CD4+ T cells and iNKT cells, play a crucial role in this protection, suggesting that targeting lipid cytotoxins could be an effective strategy for developing new therapies.
Article Synopsis
- Mycobacterium tuberculosis's tolerance to antibiotics extends TB treatment duration and leads to drug-resistant strains, particularly under nutrient-limited conditions.
- Research reveals that the outer membrane lipid phthiocerol dimycocerosate (PDIM) is crucial for this antibiotic tolerance, with certain genetic mutations affecting its production.
- By targeting PDIM production, new drug strategies could enhance existing antibiotics' effectiveness, potentially reducing treatment time and curbing drug resistance in TB patients.
Article Synopsis
- - Group B streptococci (GBS) can lead to serious issues like preterm birth and invasive diseases in newborns, showing varied virulence that helps them adapt between harmless and invasive forms.
- - A study of 229 GBS isolates from pregnant women and neonates identified specific traits, including hemolysis and certain gene variants, that correlate with increased virulence, particularly a high Granada pigment score.
- - High hyaluronidase activity was found in some isolates, notably those from stillbirth cases, suggesting a potential link between this enzyme and increased risks of severe perinatal outcomes.
Article Synopsis
- Invasive bacterial infections, particularly from Group B streptococcus (GBS), are a significant health concern, with gender differences affecting susceptibility, as shown in studies on factor XIIIA-deficient female mice.
- Male mice with higher levels of factor XIIIA displayed increased resistance to GBS, while administering FXIIIA enhanced resistance in male mice, and inhibiting it reduced resistance in females.
- The study also found that FXIIIA helps trap GBS within fibrin clots by linking it to fibronectin, and mast cell-derived FXIIIA plays a crucial role in defending against GBS infections, highlighting the complex interplay of gender and immune response.
Article Synopsis
- - The GBS-NN vaccine, designed to combat Group B Streptococcus (GBS) infections during pregnancy, has shown safety in nonpregnant women but needs further study for pregnant populations.
- - Mouse model tests revealed that vaccinated mice produced more GBS-specific antibodies, leading to better outcomes during infections compared to those that received a control treatment.
- - The study suggests that while the vaccine doesn't completely prevent GBS during pregnancy, it reduces fetal deaths and enhances neonatal survival rates after infection, indicating potential benefits of maternal vaccination.
Article Synopsis
- Group B streptococci (GBS) are harmful bacteria that can cause serious infections in newborns, leading to conditions like sepsis and meningitis, especially within their first month of life.
- Early-onset disease (EOD) occurs when neonates acquire GBS during birth, while late-onset disease (LOD) can arise from less understood sources between 7 to 89 days after birth.
- GBS infections can lead to significant long-term health issues, with over 300,000 infants affected globally each year, resulting in thousands of deaths and cases of lifelong disability, prompting a need for better understanding and prevention strategies.
Article Synopsis
- Group B streptococcus (GBS) is a common bacteria in the vaginal tract that can lead to serious complications during pregnancy, such as preterm birth and neonatal infections.
- Despite progress in understanding how GBS causes disease, there is still no approved vaccine, making its prevention a top priority.
- The review emphasizes the importance of both bacterial factors and host defenses in the development of GBS infections, and suggests that targeting these interactions could help lower the risk and impact of GBS-related issues.
Article Synopsis
- A variety of pathogens can harm fetuses and cause congenital malformations through teratogenesis, with Rubella virus historically recognized as the first infectious agent linked to such defects during pregnancy.
- Human cytomegalovirus (HCMV) is currently the leading cause of congenital malformations worldwide, affecting 1 in 200 infants, while emerging diseases like Zika virus have shown the ability to induce severe injuries in newborns.
- Animal models, particularly non-human primates, are essential for understanding how these pathogens cause harm and for developing effective vaccines and treatments to prevent adverse pregnancy outcomes.
Article Synopsis
- - Invasive bacterial infections, like those caused by Group B streptococci (GBS), significantly raise risks for negative pregnancy outcomes such as preterm birth and stillbirth due to their ability to infect the maternal-fetal area.
- - A research study using a nonhuman primate model revealed that GBS expressing the enzyme hyaluronidase (HylB) led to consistent bacterial invasion into the amniotic cavity, fetal infection, and preterm labor.
- - The findings suggest that HylB allows GBS to evade immune responses and cause preterm labor by increasing certain inflammatory markers, highlighting the need for better strategies to prevent these issues during pregnancy.
Article Synopsis
- Group B streptococci (GBS) are harmful bacteria linked to serious pregnancy and neonatal complications, with a key virulence factor being β-hemolysin/cytolysin (granadaene), which is found on their surfaces.
- The study found that GBS releases pigmented membrane vesicles (MVs) that contain active granadaene and are associated with increased cell death in immune cells.
- These hemolytic MVs enhance the bacteria's ability to survive and worsen disease severity in neonatal mice, suggesting they play a significant role in GBS infection and virulence.
The invasion of a suitable host hepatocyte by Plasmodium sporozoites is an essential step in malaria infection. We demonstrate that in infected hepatocytes, lysosomes are redistributed away from the nucleus, and surface exposure of lysosome-associated membrane protein 1 (LAMP1) is increased. Lysosome exocytosis in infected cells occurs independently of sporozoite traversal.
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- Preterm birth is a significant cause of neonatal death and is often triggered by infections that ascend from the lower genital tract, affecting the placenta and fetus.
- The study investigates the cervical mucus plug (CMP) from healthy pregnancies to identify its antimicrobial properties against group B streptococcus (GBS), a bacteria linked to preterm birth.
- Although the antimicrobial peptides found in CMPs are not concentrated enough to kill GBS directly, they can activate leukocytes, enhancing the body's ability to kill bacteria, which suggests the CMP plays a role in preventing infections that could lead to preterm birth.
Article Synopsis
- Bacteria use a two-component signal transduction system to regulate gene expression based on phosphate levels, with the tuberculosis-causing bacterium needing this system for its virulence and resistance to drugs.
- The study focused on proteins similar to PhoU, revealing that both PhoU1 and PhoU2 work together to inhibit the SenX3-RegX3 system, especially when phosphate is abundant, with their deletion leading to increased gene expression.
- Through genome sequencing of deletion mutants, the researchers found that the absence of PhoU proteins caused reliance on mutations that disrupt the phosphate transporter, indicating that the PhoU proteins help manage both phosphate signaling and uptake.