I Love Histology and Herpetology

  Klasifikasi (might be outdated as I wrote this a couple of years back):  Kingdom     : Animalia  Phylum        : Chordata  Subphylum  : Vertebrata  Class            : Reptilia  Order           : Squamata  Suborder      : Lacertilia  Family          : Agamidae  Genus           : Bronchocela  Species         : Bronchocela cristatella Dumeril & Bibron, 1837  Sisik kepala bagian atas kecil, berlunas, sedikit melebar di bagian supraokular; dua atau tiga sisik memipih di belakang tepi suprasiliar; timpanum lebar, setengah atau lebih dari diameter mata. Sembilan sisik labial atas dan bawah. Kantong gular berukuran kecil dengan sisik berlunas; tidak ada lipatan di bagian pundak. Nuchal crest berdiri tegak seperti duri, yang paling panjang beru...

Klasifikasi: Kingdom          : Animalia Phylum             : Chordata Subphylum       : Vertebrata Class                : Reptilia Order                : Squamata Suborder          : Lacertilia Family              : Agamidae Genus               :  Draco Species            :  Draco volans  Kepala berukuran kecil, moncong tidak atau sedikit lebih panjang dibandingkan diameter mata. Lubang hidung terletak di kepala bagian samping, timpanum berukuran lebih kecil dibandingkan lebar bukaan mata. Sisik kepala uk...

   Klasifikasi: Kingdom        : Animalia Phylum           : Chordata Subphylum     : Vertebrata Class              : Reptilia Order              : Squamata Suborder        : Lacertilia Family            :  Scincidae Genus             :  Eutropis Species            :  Eutropis multifasciata    Moncong berukuran pendek dan tumpul. Kelopak mata bagian bawah ditutupi oleh sisik. Bukaan telinga lebar dan bulat, berukuran setengah dari lebar bukaan mata. Lubang hidung terdapat di bagian  posterior  sisik  nasal . Terdapat sis...

Subordo Lacertilia umumnya adalah hewan pentadactylus dan bercakar, dengan bentuk dan struktur sisik yang bervariasi. Kulit Reptilia sebagian besar termodifikasi menjadi sisik dan menutupi hampir seluruh permukaan luar tubuhnya. Sisik pada Squamata umumnya tersusun tumpang tindih (overlapping). Namun, sisik pada Lacertilia dapat tersusun granular, tumpang tindih ataupun tidak beraturan, dapat pula dilengkapi dengan lunas ataupun tidak. Sisik tersebut terbuat dari bahan tanduk. Sisik pada anggota Lacertilia seringkali termodifikasi menjadi tuberkulum ataupun spina. Sisik-sisik ini dapat mengelupas. Pengelupasannya berlangsung sebagian dalam artian tidak semua sisik mengelupas pada saat yang bersamaan (Zug, 1993).  Anggota Subordo Lacertilia memiliki kelopak mata dan lubang telinga. Lidah Lacertilia panjang dan adapula yang bercabang. Pada beberapa spesies lidah ini dapat ditembakkan (projectile) untuk menangkap mangsa seperti pada genus Chamaeleon. Cauda pada Subordo Lacertilia memi...

Gekko gecko (Tokay Gecko), locally known to Indonesians as Tokek, is a member of Suborder Lacertilia which can be found from northeast India to southern China and throughout Southeast Asia. There are two identified subspecies of Tokek, those are G. g. gecko (Linnaeus, 1758) and G. g. azhari (Mertens, 1955), the latter is endemic to Bangladesh. This arboreal lizard naturally lives in tropical rain forest but some of them have entered human habitation (Kongbuntad et al., 2016). The taxonomical classification of G. gecko displayed on Integrated Taxonomic Information System (ITIS) is as followed:  Kingdom       : Animalia  Phylum            : Chordata  Subphylum    : Vertebrata  Class              : Reptilia  Order             : Squamata  Suborder        : Gekkota  Family   ...

Aggrecan (Acan) belongs to the chondroitin sulfate proteoglycans of the lectican family, namely hyalectans family. Members of this family are vital components of extracellular matrix (Adams et al., 2007; Aspberg, 2012). Acan, one of the chondrocyte specific markers, is essential for cartilage function and skeletal development (Nirmal & Nair, 2013). Acan acts as the main compressive macromolecule in cartilage tissue, making bone capable to withstand physical loading, showing how important this molecule is in maintaining cartilage integrity (Lee et al., 2010). In the precartilaginous anlagen, the condensed mesenchymal cells express versican which is then down-regulated during chondrogenic differentiation as Acan is up-regulated (Lauinga et al., 2014). Chondrocytes in the proliferative zone produce a large amount of extracellular matrix predominantly consisting of type II collagen and Acan. When chondrocytes differentiate into pre-hypertrophic and hypertrophic chondrocytes, there is a...

Matrix Gla protein (MGP) is a member of the mineral-binding Gla protein family with the molecular weight of 10-kD and known to be involved in cartilage mineralization during development. MGP is expressed in chondrocytes, endothelial cells and vascular smooth muscle cells (Dan et al., 2012; Yao et al., 2009). The five γ-carboxyglutamic acid (Gla) residues of this protein possess high affinity for ions such as calcium and phosphate (Newman et al., 2001; Beazley et al., 2013) which enable it to prevent extracellular matrix calcification by binding the minerals thus limiting the amount of free calcium ions available to initiate calcification (Yagami et al., 1999; Dan et al., 2012). It has been reported that MGP does not only inhibit cartilage mineralization, but it also blocks chondrocyte maturation and both types of ossification (Yagami et al., 1999). Mineralization begins in matrix vesicles which is associated with MGP and at sites with accumulated proteoglycan. MGP inhibits calcium infl...

Chondrocytes express chondrocyte-specific extracellular matrix proteins such as type II, IX, XI collagens and aggrecan, while the hypertrophic chondrocytes tend to produce matrix high in type I and X collagens (Cancedda et al., 1995; Erlebacher et al., 1995; Hall & Miyake, 1995; Niu et al., 2016). Type II collagen is encoded by the type II procollagen gene (Col2a1) (Hering et al., 2014; Cruet-Hennequart et al., 2015) and its expression is usually used as an early key marker of chondrogenic cells (Mori-Akiyama et al., 2003; Xu et al., 2008). In mouse embryo, Sox9 is co-expressed with Col2a1, suggesting that direct activation of Col2a1 by Sox9 is crucial in activating genes that encode cartilage extracellular matrix proteins (Lefebvre & de Crombrugghe, 1998; Lefebvre et al., 1998; Grogan et al., 2008). Chondrocytes begin to synthesize type II collagen in the form of a procollagen molecule with a triple-helical α1 (II) chains. This procollagen molecule has an amino and carboxyl pr...

Skeletal tissues express bone morphogenetic proteins (BMPs) which act as regulators of skeletal development and maintenance of bone mass in adults (Gamer et al., 2009). BMPs belong to the transforming growth factor-β superfamily (Bahamonde & Lyons, 2001) and are expressed throughout the developing skeleton, influencing cell type specification, cell differentiation and apoptosis during endochondral ossification. At the earliest stages of osteogenesis, BMPs are required for mesenchymal condensation and at the later stages, BMPs-receptor complexes stimulate chondrocyte proliferation and differentiation (Gamer et al., 2010).  BMP3 molecule is structurally related to BMPs but it acts as a negative regulator of osteogenesis (Bahamonde & Lyons, 2001; Gamer et al., 2010; Huang et al., 2007). BMP3 is mainly produced by osteoblasts and osteocytes (Long & Ornitz, 2013). This molecule is present within bone and accounts for almost 65% of total BMP (Zhang et al., 2015; Zhou et al., ...

Lizard tail regeneration, particularly the cartilage regeneration, is a compelling phenomenon to be studied as it has been widely known that the regenerative capacity of cartilage after injury/trauma is very limited (Tuan et al., 2013). Urodeles are capable to regenerate tissues similar to the originals (Lozito & Tuan, 2015) while the regenerated tail of lizard is considered as an imperfect replica due to the several anatomical differences (Fisher et al., 2012). One stand out structure of those imperfections is that the axial skeleton of regenerated tail is lack of bony structures, but instead, it is composed of cartilage (Alibardi & Meyer-Rochow, 1989). The caudal vertebrae of the original tail will be replaced by a continuous, unsegmented cartilage tube surrounding the growing ependymal canal. This cartilage tube only exists in the regenerated tail of lizard and is maintained throughout the life of the organism. An experiment conducted by Lozito & Tuan (2015) showed that ...

Lizard ability to regrow its tail following tail amputation is known as regeneration (Hutchins et al., 2016). Regeneration process is initiated by the formation of blastema from the dedifferentiated cells (Daniels et al., 2003; Alibardi & Lovicu, 2010). Later on, Alibardi (2015) stated that progenitor cells also play an important role in this process. These blastemal cells will proliferate and then differentiate to form new tissues to replace the lost/damaged tissue (Carlson, 2007; Narayanan, 2015). Regeneration process is divided into four stages: (1) wound healing stage, lasting up to 10 days post-autotomy (dpa); (2) blastema formation ranging from 10-15 dpa; (3) tail growth and differentiation ranging from 15-25 dpa; and (4) tail maturation when the tail becomes fully scaled (Alibardi, 2009) which is usually studied from 25-60 dpa (Fisher et al., 2012) with no currently known endpoint. Ependymal cells lining the central canal of the original spinal cord appear to be crucial for ...

Tail autotomy is a common defense mechanism found in lizards (Bely & Nyberg, 2010; Hill et al., 2012; Russell et al., 2015). The autotomized tail will continue to twitch for up to 30 minutes due to the event of anaerobic metabolism (Dial & Fitzpatrick, 1983; Higham & Russell, 2010). This event will divert the attention of predator, giving a chance for the lizard to escape (Daniels, 1983). Even though autotomy may save their lives, lizards performing autotomy have to deal with the loss of tail vital functions in movement (Bateman & Fleming, 2009), establishing social status (Fox & McCoy, 2000; Meyer et al., 2002), and as fat-storage organ (Clark, 1971). Lizards which are using their tail to store fat most likely return to the site where they lost their tail and eat the autotomized tail to make up for the loss of the major fat reserve which comprises half or more total body fat (Congdon et al., 1974; Lin et al., 2006; Naya et al., 2007; Sanggaard et al., 2012). Moreov...

McLean and Vickaryous (2011) studied epimorphic regeneration in Eublepharis macularius (Leopard Gecko) and the results showed that the transverse section of the tail is circular to ovoid and the skeletal system is located in the center. The histological observation also showed that the tail is separated into quadrants by the presence of connective tissue known as septa emerging from (1) the neural spine in the dorsal region, (2) chevron bone in the ventral region, and (3) transverse processes on both lateral sides. Both dorsal (epaxial) and ventral (hypaxial) quadrants consist of perivertebral adipose tissue, connective tissue and musculature. The outer part of the tail is well-protected by integument system modified into scales. Various tissues lie under the skin, from the outside in: segmented musculature, perivertebral adipose tissue surrounding the caudal vertebrae and the spinal cord located inside the vertebral canal. Peripheral nerve fibers can be found in the adipose and muscle...

Regenerative medicine has been a cutting edge field at present as it holds the key in revealing many unknown processes involved in tricky degenerative diseases or cancers. Many approaches have been performed to uncover the underlying mechanisms of regeneration process. Generally, the term regeneration refers to the ability of an organism to restore damaged or lost tissue with no formation of scar tissue, and the newly formed tissue is able to function the same as the original (Pirotte et al., 2016). The capacity of regeneration in human is limited only to bone healing, repair of skin cuts and regeneration of liver, muscle, bone, blood and epithelia (Narayanan, 2015), but there are some organisms showing impressive regeneration capacity such as zebra fish, salamanders and lizards. Those animals are commonly used as models for regeneration studies as they can provide molecular insights of inherent regenerative capacity (Kurup & Ramachandran, 2011). Taxonomically, lizard which belong ...