Fimbriae & Hami: Videos & Practice Problems

Fimbriae are short, filamentous proteins on bacterial surfaces that facilitate adherence between cells and to surfaces, playing a crucial role in biofilm formation. In contrast, hammy are unique to archaeal cells, serving as hook-like appendages that enable attachment to each other and to bacterial cells within biofilms. Both structures are essential for microbial community stability and interaction, highlighting their importance in microbial ecology and pathogenesis.

Fimbriae & Hami

This video, we're going to begin our lesson on fimbriae and hammy. Fimbriae are actually filaments of a pilon protein that are shorter than pili themselves, and they extend from the cell surface of many bacteria. Now the functions of these fimbriae are to adhere cells to one another or to another surface. They are really involved in the formation of biofilms, those communities of microbes that live together within an extracellular polymeric substance. If we take a look at this image down below, you can see that fimbriae adhere to each other connecting cells in a biofilm. Notice that we're showing you a biofilm over here, this community of microbes encased in this extracellular polymeric substance or this EPS structure that you see here. All of these microbes that you see here are living within this biofilm. Zooming into these bacterial cells right here, notice that the bacterial cells have these little structures that are projecting off their surface. These tiny structures that are projecting off of the cell surface are the fimbriae. Once again, these fimbriae function in helping these cells to adhere to each other. You can see that they are going to interact with each other, adhering to each other. But also it allows the cells to adhere to other surfaces as well. They are going to be very important in the formation of biofilms. This here concludes our introduction to fimbriae. Later in our next video, we'll introduce Hammy. So I'll see you all there.

The presence of fimbriae on a bacterial cell is most likely to have a critical role in

• A. Conjugation
• B. Chemotaxis
• C. Biofilm formation
• D. DNA replication

Answer: (C)

Hami

In this video, we're going to introduce hami. And so hami are short filamentous proteins that are only found on the surface of archaeal cells. And so these hami are specific to archaea and are not really found on bacteria or eukarya. And the hami, they serve as hook-like appendages that act like grapples to allow them to attach to each other and to allow them to attach to other bacterial cells. And so archaeal cells that have hami, they can be found within biofilm communities. And, biofilm communities that have bacterial cells since they can attach to bacterial cells. And so in this example down below, we're showing you how archaeal cells can produce long filamentous cell surface proteins called hami, and how those hami can be found on archaea within biofilms. And so once again over here on the right-hand side, we're showing you a biofilm. And zooming into a region of the biofilm, notice that there are archaea here. And these archaea, on their cell surface, they have these structures that are projecting off, and these structures are representing the hami. And the hami, once again, are going to be the short filamentous proteins that extend only off of the surface of archaeal cells, and they act like hook-like appendages, similar to grapples that allow them to hang on to each other and attach to each other and other bacterial cells as well. And so they're important in the formation of biofilms. And so this here concludes our brief lesson on Hami, and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

Which of the following structure is found only in archaea?

• A. Peptidoglycan
• B. Hami
• C. Fimbriae
• D. Pili

Answer: (B)

Here’s what students ask on this topic:

What are fimbriae and what role do they play in biofilm formation?

Fimbriae are short, filamentous proteins found on the surface of many bacterial cells. They are composed of pilin protein and are shorter than pili. Fimbriae play a crucial role in biofilm formation by facilitating the adherence of bacterial cells to each other and to various surfaces. This adherence is essential for the development of biofilms, which are communities of microbes encased in an extracellular polymeric substance (EPS). Within these biofilms, bacteria can communicate, share nutrients, and protect themselves from environmental stresses, including antibiotics. Therefore, fimbriae are vital for microbial community stability and interaction.

How do hammy differ from fimbriae in terms of structure and function?

Hammy are short, filamentous proteins found exclusively on the surface of archaeal cells, whereas fimbriae are found on bacterial cells. Structurally, hammy act like hook-like appendages or grapples, allowing archaeal cells to attach to each other and to bacterial cells within biofilms. In contrast, fimbriae are composed of pilin protein and primarily facilitate adherence between bacterial cells and surfaces. Functionally, both structures are essential for biofilm formation and microbial community stability, but hammy are unique to archaea and are not found in bacteria or eukarya.

Why are fimbriae important in microbial ecology and pathogenesis?

Fimbriae are important in microbial ecology and pathogenesis because they enable bacteria to adhere to each other and to surfaces, facilitating the formation of biofilms. Biofilms provide a protective environment for bacteria, allowing them to survive in harsh conditions and resist antibiotics. This adherence capability is crucial for the colonization of host tissues, making fimbriae a key factor in bacterial infections and pathogenesis. Additionally, biofilms play a significant role in natural ecosystems by contributing to nutrient cycling and microbial interactions, highlighting the ecological importance of fimbriae.

What is the significance of hammy in archaeal biofilms?

Hammy are significant in archaeal biofilms because they enable archaeal cells to attach to each other and to bacterial cells, facilitating the formation and stability of biofilms. These hook-like appendages act as grapples, allowing archaeal cells to anchor themselves within the biofilm matrix. This attachment is crucial for the survival and interaction of archaeal cells within mixed microbial communities. By contributing to biofilm formation, hammy play a vital role in the ecological functions and resilience of archaeal populations in various environments.

How do fimbriae and hammy contribute to the stability of microbial communities?

Fimbriae and hammy contribute to the stability of microbial communities by facilitating the adherence of cells to each other and to surfaces, which is essential for biofilm formation. Fimbriae, found on bacterial cells, help bacteria adhere within biofilms, providing a protective environment and enhancing resistance to environmental stresses. Hammy, found on archaeal cells, act as hook-like appendages that allow archaea to attach to each other and to bacterial cells, promoting the integration and stability of mixed microbial communities. Together, these structures ensure the cohesion and resilience of microbial populations in various environments.