Third batch of oral reports (For December 30, 2021-January 2, 2022

BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Ayesha Elianne Razuman -
Number of replies: 7

Greetings, everyone!

We, Quinto, Razuman, and Santos, are the members of Group 6 under BIO 133 LEC2 (TF 10:00 - 11:30). Our report is on the study of Alibardi (2020) entitled, "Immunolocalization of corneous beta proteins of the epidermal differentiation complex in the developing claw of the alligator," and the video will be accessed through this Google drive link: https://drive.google.com/file/d/1yGR08GEC07nKPJBDzmD0oleCZ66Ny1O-/view?usp=sharing

Meanwhile, the study will be accessed through this link: https://drive.google.com/file/d/1tJQNx2VP8kz3rzYoizen5WoGe3QNbQZi/view?usp=sharing

If you have any questions regarding our presentation, please feel free to comment below!

Thank you very much and have a good day!

In reply to Ayesha Elianne Razuman

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Lydia LEONARDO -
Thank you for a very interesting report on claw formation. My questions are:
1. Please tabulate the differences between the unguis and the subunguis.
2. Would this development in crocodilians be similar to the development of unguis and subunguis in the hoofs of mammals?
Thank you.
In reply to Lydia LEONARDO

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Regina Abigail Santos -
Good day, Ma'am Leonardo! Thank you for your questions! To answer your first question, i.e., to tabulate the summary of the differences between unguis and subunguis, our group prepared the table below based on the findings of Alibardi (2020):
 
The image shows the differences between unguis and subunguis.
In reply to Lydia LEONARDO

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Regina Abigail Santos -
As for the second question, here is our group's answer: 

The unguis in mammalian hooves and crocodilian claws are both well-developed, have harder consistency than the subunguis, and curve all the way around the digital end enclosing the subunguis (Tariquil, 2021). Although the morphology of claws and hooves appear different in adult reptiles and mammals, their development is quite similar in the following stages (Hamrick, 2001): (1) epithelial thickening or placode formation; (2) appearance of the transverse groove and formation of the primordial germinal matrix; and (3) cell differentiation of the germinal matrix to a keratinized layer. These similarities can be attributed to the fact that like reptiles, mammalian claws or hooves derive from a thickening of the embryonic epidermis of the dorsal tips of digits. However, in mammals, the growth of claws and hooves occurs by the continuous production of new keratinocytes from a proximal germinal matrix. In contrast, crocodilian claws show an extended matrix zone, as do their scales, and proliferation is not exclusively concentrated in a proximal matrix zone (Khanoon et al., 2015).

References:
 
Hamrick, M. W. (2001). Development and evolution of the mammalian limb: Adaptive diversification of nails, hooves, and claws. Evolution and Development, 3(5), 355–363. doi:10.1046/j.1525-142x.2001.01032.x
 
Khannoon, E. R., Russell, A. P., & Tucker, A. S. (2015). Developmental mechanisms underlying differential claw expression in the autopodia of geckos. EvoDevo, 6(8). . https://doi.org/10.1186/s13227-015-0003-9

Tariquil, I. G. (2021). Exoskeleton Derivatives of Mammals. http://www.surendranathcollege.org/new/upload/TARIQUL_ISLAM_GOLDARExoskeleton%20Derivatives2021-02-16Exoskeleton%20Derivatives.pdf
In reply to Ayesha Elianne Razuman

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Nicole Kate Ashlynn Ngo -
Hello Jamaica, Ayesha, and Regina!

First and foremost, we would like to commend your group for being able to put together a very comprehensive and informative report. Our group (Idorot, Ngo, Urbano - Group 9) would just like to ask one question. In your report, it was mentioned that beta cells of the unguis appeared relatively larger and fusiform as compared to those of the subunguis. What are the implications of these differences observed in the beta cells found in these two regions, considering their role in the development of alligator claws?
In reply to Nicole Kate Ashlynn Ngo

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Jamaica Quinto -

Thank you for your question, Nicole, Ivanne, and Juan. 


The differences in size and shape of the beta cells found in unguis and that of the subunguis can be explained by their differences in beta-cell proliferation and movement pattern (Alibardi, 2020). Unguis exhibits higher proliferation during development and growth and is composed of a compact corneous layer made of separated but tightly interlocked corneocytes. Conversely, subunguis displays lower proliferation and is characterized by a softer layer whose superficial corneocytes desquamate. Moreover, their movement pattern differs such that the proliferating beta-cells in the unguis are moving within epithelial layers, probably toward the apex of the developing claw. Meanwhile, beta-cells from the tip of the unguis move downward into the distal-most region of the subunguis (Alibardi, 2020).


Consequently, more beta cells in the unguis imply faster growth than the subunguis, allowing the former to be curved all around the end of the digit at the same time, covering the latter. Meanwhile, the thin corneous layer in the subunguis implies the initial presence of keratohyalin-like granules, which are storage vesicles for major corneocyte proteins (Alibardi, 2008; Amen et al., 2013). Notably, the combined movement of the beta-cells in the unguis and subunguis contributes to sharpening the crocodilian claw which is necessary to achieve its function, such as the grasping and tearing of a prey (Alibardi, 2020).


References:

Alibardi, L. (2008). Cornification in developing claws of the common Australian skink (Lampropholis guichenoti) (Squamata, Lacertidae). Italian Journal of Zoology, 75(4), 327–336. https://doi.org/10.1080/11250000801973334. 


Alibardi, L. (2020). Immunolocalization of corneous beta proteins of the Epidermal Differentiation Complex in the developing claw of the alligator. Annals of anatomy, 231, 151513. https://doi.org/10.1016/j.aanat.2020.151513


Alibardi, L. (2021). Development, structure, and protein composition of reptilian claws and hypotheses of their evolution. Anatomical record (Hoboken, N.J. : 2007), 304(4), 732–757. https://doi.org/10.1002/ar.24515


Amen, N., Mathow, D., Rabionet, M., Sandhoff, R., Langbein, L., Gretz, N., Jäckel, C., Gröne, H. J., & Jennemann, R. (2013). Differentiation of epidermal keratinocytes is dependent on glucosylceramide:ceramide processing. Human molecular genetics, 22(20), 4164–4179. https://doi.org/10.1093/hmg/ddt264

In reply to Ayesha Elianne Razuman

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Eliana Rachelle Tamana -
Hi Jamaica, Ayesha, and Regina!

I am Eliana Rachelle Tamaña from Group 8; on behalf of my groupmates Mariel Jose and Dino Spencer Pabilico, we would like to commend your group for an informative and well-explained presentation about claw formation. The report was very comprehensive and detailed which is why it became easier for us to follow and understand the flow of the study. To extend the discourse on this topic, we would like to know if this immunolocalization phenomenon of corneous beta proteins also applies to other reptiles and birds, given that you have mentioned a similar claw formation pattern among them? Similarly, we would like to know if the same corneous beta proteins mentioned in the report are observed among these animals?

Thank you very much!
In reply to Ayesha Elianne Razuman

Re: BIO 133 LEC2 (TF 10:00-11:30 AM) — Formation of Skin and Derivatives

by Jianne Paula Palonpon -
Hi Ayesha, that was an interesting report on the proliferation and distribution of corneous beta proteins in the developing claws. We would like to thank your group for taking the time to impart this knowledge on us. I'd like to ask about the implications of the results of the research in the field of development biology, specifically its significance for the evolutionary relationships of animals such as reptiles, amphibians, and avians? I'm looking forward to learning more about your topic!