House Lizard Research Articles

Motion dazzle camouflage as an escape strategy in Hemidactylus frenatus, (Common house lizard) of Chennai, Tamil Nadu

Hemidactylus frenatus, is the common house lizard, which is frequently found in almost all Indian households. This lacertilian member is a warm blooded reptile and had been a triumphant lizard species on earth. The success of these lizards, in evolution, may be attributed to their unique ability to disguise as according to the backgrounds they inhabit. Quite a number of studies, on different species, of lizards have revealed that geckos are known to engage in “motion dazzle camouflage" to avoid predation. The present investigation was conducted to ascertain, if common house wall lizards actually engage in a similar kind of dazzle camouflage to evade aggression. Observational studies, for a period of two years spanning from 2019-2021, showed that the common wall lizards, indeed engage in one form or the other type of crypsis to avoid human or animal encounters. Results showed that, geckos which were generally found on lighter backgrounds such as light colored walls had a paler skin hue, matching to their lighter environment, and thus concealing them to certain extent. However it was interesting to note that, the lizards, which were adapted to run on the floor or adapted to move on patchy backgrounds, showed a molted appearance on their skin. They had alternate dark and light patches, on the dorsal side, extended from the neck till the tip of the tail, aiding these lizards, to conceal and avert any conflict. The molted appearance on the lizards may be because of opsin proteins present in their skin, which act as photo sensors, capable of adapting accordingly to the light intensities and there by assisting in defensive pigmentation. The blotched appearance of geckos implies that it causes the motion dazzle camouflage there by confusing the predator, about its exact location and avoids the threat. The present study, precisely suggests, that the common wall lizards of the species, Hemidactylus frenatus indulges in motion dazzle camouflage, as an efficient game plan to avoid and evade any adversaries.

Molecular identification of lizard by RAPD & FINS of mitochondrial 16s rRNA gene

In the present study, we identified the structure-less skeleton suspected to be of house lizard present in jaggery, consumption of which caused mass food poisoning using, RAPD (Random Amplification of Polymorphic DNA) with random primers and FINS (Forensically Informative Nucleotide Sequencing) with mitochondrial 16s rRNA gene. The NJ tree dendogram based on distance calculated from RAPD bands clearly identified the structure-less as Calotes versicolor (Garden Lizard). In FINS analysis of the mitochondrial 16s rRNA gene the NJ tree based on Kimura-2-parametere distance matrices clearly reveal that the unknown sample clustered with Agmidae family and closest to Calotes versicolor (Garden Lizard) with 100% bootstrap support, whereas all other species belong to Gekkonida family form a single distinct cluster including Hemidactylus fluviviridis (House Lizard). This is the first successful typing of mitochondrial 16s rRNA with FINS approach to identify the biological origin of a structure-less skeleton. Our analysis also sustained successful identification of unknown samples using RAPD method with optimized conditions in a laboratory setup with low resources.

Sac-like pouches in Blastocystis from the house lizard Cosymbotus platyurus.

Sac-like pouches in Blastocystis from the house lizard Cosymbotus platyurus.

The occurrence of neurons with strongly negatively charged surface coats in mammalian, avian, reptilian, amphibian and piscine brains.

Neurons with strongly negatively charged surface coats were recognized in mammalian, avian, reptilian, amphibian and piscine brains. Many large-sized neurons had strongly negatively charged surface coats in the visual cortex and brain stem of the cow, cat, guinea pig, mouse, quail and parakeet. Such neurons were also seen in the brain stem of the lower vertebrates such as the house lizard, Japanese terrapin, bullfrog, newt, carp and sweetfish.

Prostaglandin Metabolism during Cell Aggregation in the Regenerating Vertebrate Appendage: (tail regeneration/fatty acids/prostaglandins/cell aggregation/HPLC.).

Prostaglandin metabolism during cell aggregation period was studied in the regenerating tail of the house lizard. On the basis of scanning electron microscopy it was observed that similar kinds of cells in the blastema aggregate to form promuscie aggregate and procartilage aggregate on the 13th day of tail regeneration. In order to understand the prostaglandin metabolism the following parameters were analysed. Fatty acid composition of phospholipids and free fatty acids analysed by gas chromatography. The activity of two rate limiting enzymes-phosholipase A and C, and the activity of the enzymes which are responsible for the oxygenation of polyunsaturated fatty acids-lipoxygenase and cycloxygenase were also estimated. The characterization of the endogenous prostaglandins were carried out by high performance liquid chromatography. On the basis of the above investigations, we observed an increase in phospholipase C activity and resultant increase in free arachidonic acid level. High activity of cycloxygenase and presence of prostaglandin E2 (PGE2) were also observed PGE2 was reported to stimulate cAMP production and resultant cell differentiation. These observations suggest the involvement of prostaglandin metabolism during cell aggregation period in the regenerating blastema and resultant cytodifferentiation of blastemal cells.

Possible role of <i>β</i>-glucuronidase in the normal and regenerating tail of the house lizard, <i>Hemidactylus flaviviridis</i>

Histochemical demonstration of beta-glucuronidase was carried out in the normal and regenerating tail of the house lizard, Hemidactylus flaviviridis. Greater enzyme activity was particularly discernible in the stratum germinativum of the skin of the normal and fully regenerated tail. During regeneration most of the cellular elements of the blastema and the differentiating regenerate exhibited enzyme activity. Distribution of the enzyme beta-glucuronidase is correlated with the high degree of cellular proliferation. The role of the enzyme in the catabolism of mucopolysaccharides is also implicated during the wound-healing phase. In the full-grown regenerate the intensity and distribution of the enzyme activity were found to be the same as those observed in the normal tail.

Eimeria cicaki sp. n. and Isospora thavari sp. n. from the house lizard Gehyra mutilata Boulenger in Malaysia.

Oocysts and endogenous stages of new species of Eimeria and Isospora from the house lizard, Gehyra mutilata, are described. The ellipsoid to subspherical 2-layered oocysts of E. cicaki averaged 24.0 X 21.0 mum. Polar granules are present. Micropyle and oocyst residuum are absent. Ellipsoid sporocysts average 12.2 X 9.0 mum. A sporocyst residuum is present, but the Stieda body is absent. Endogenous stages are in epithelial cells of the small intestine. The subspherical single-layered oocysts of I. thavari average 23.8 X 22.8 mum. The polar granule is present; micropyle and oocyst residuum are absent. Ellipsoid sporocysts average 12.8 X 9.4 mum. Stieda body and sporocyst residuum are present. There are endogenous stages in epithelial cells of the small intestine.

Histochemical localization of glucose-6-phosphate dehydrogenase (G-6-PDH) in the normal and regenerating tail of the house lizard,Hemidactylus flaviviridis

Summary G-6-PDH was histochemically demonstrated in the normal and regenerating tail of the house lizard, Hemidactylus flaviviridis. High enzyme activity in epidermal cells of normal and regenerating tail skin and wound epithelial cells indicates utilization of glycogen through the pentose phosphate cycle. The skeletal muscles of normal tail, blastema cells, differentiating muscle and cartilaginous cells suggest operation of the HMP shunt which provides pentose sugars and NADPH for nucleic acid, fatty acid, and probably also for polysaccharide synthesis.

Histochemical Localization of Lactate and Malate Dehydrogenases in the Normal and Regenerating Tail of the House Lizard, Hemidactylus Flaviviridis

Histochemical Localization of Lactate and Malate Dehydrogenases in the Normal and Regenerating Tail of the House Lizard, Hemidactylus Flaviviridis

Studies On Glycogen, Glycogen Synthetase and Respiratory Quotient in the Normal and Regenerating Tail of the House Lizard, Hemidactylus Flaviviridis

Quantitative estimations of glycogen, histochemical demonstration of glycogen synthetase, and a study of Respiratory Quotient (RQ) in the normal and regenerating tail of the house lizard, Hemidactylus flaviviridis were carried out. Fluctuations in the glycogen content along with those in the activity of glycogen synthetase were noticed during the various phases of regeneration. RQ values of the tissues of the normal and fully regenerated tails were indicative of a prevalent carbohydrate utilization for energy requirements. General paucity of glycogen and lack of glycogen synthetase activity were noticed during the blastema phase. During the same period a considerable fall in the RQ was also noticed. During differentiation appearance of glycogen synthetase and a considerable rise in the glycogen content were discernible. However, as the differentiation progressed there was a drop in the level of glycogen and the RQrecorded during the period gave an indication of utilization of carbohydrates. In the full grown regenerate the glycogen content, glycogen synthetase activity and RQ were comparatively closer to their corresponding levels in the normal tail.

Dynamics of phospholipid metabolism in the sexual segment and kidney of the indian house lizard, Hemidactylus flaviviridis ruppell

1. 1. The incorporation of radioactive inorganic orthophosphate into the sexual segment and kidney phospholipids was studied at various time intervals in sexually active and regressing lizards and following castration and testosterone administration. 2. 2. The incorporation of the label into the total phospholipids of the sexual segment as well as into the kidney is gradual and reaches a peak at 12 hr followed by a gradual decrease at later time intervals. 3. 3. Phosphatidic acid + polyglycerol phosphatide and phosphatidyl inositol+ phosphatidyl serine fractions incorporate the label rapidly during the first 30 min, while phosphatidyl choline and phosphatidyl ethanolamine fractions show heavy label at later intervals. The pattern of incorporation is similar in the phospholipids of the sexual segment and kidney, but the intensity of incorporation in the sexual segment is higher during the active season than in the regresssing season. 4. 4. Rapid early incorporation of the precursor into the phosphatidic acid fraction suggests its role in the biosynthesis of other complex lipids. The differential stimulation of the uptake of the label by sexual segment phospholipids is clear evidence of the selective action of testosterone on this target organ.

Seasonal variations in the pattern of lipids in the sexual segment, kidney and liver of the indian house lizard, Hemidactylus flaviviridis ruppell

1. 1. Various lipid classes of the sexual segment, kidney and liver of the Indian house lizard were studied during different periods of the year. 2. 2. Incorporation of radioactive inorganic orthophosphate into total phospholipid of the sexual segment and kidney was also investigated during different phases of reproductive activity. 3. 3. Lipids of the kidney and liver are presumably utilized by the sexual segment for the synthesis of its lipids during its development in December and January when the animals hibernate. 4. 4. Selective enhancement of phospholipid synthesis by the sexual segment during February–April, indicates that this is under the influence of testicular androgens.

Dynamics of phospholipid metabolism in the sexual segment and kidney of the Indian house lizard, Hemidactylus flavivridis Ruppell.

Dynamics of phospholipid metabolism in the sexual segment and kidney of the Indian house lizard, Hemidactylus flavivridis Ruppell.

Effect of temperature acclimation, X-irradiation and tail amputation on incorporation of leucine- 14C into hepatic proteins of the house lizard ( Hemidactylus leschenaulti)

1. 1. Synthesis as well as the turnover of proteins is higher in the liver of animals acclimated to 37°C than in that of animals acclimated to 24°C. 2. 2. X-irradiation and tail amputation enhanced the incorporation of labelled leucine into proteins. The effect on the rate of incorporation is highest during the first hour after irradiation or amputation. 3. 3. The treatments did not seem to affect the total protein content during the course (150 min) of the experiments.

Seasonal changes in the testicular lipids and after hypophysectomy in the Indian house lizard, Hemidactylus flaviviridis Ruppell

Changes in the different classes of lipids in the testis of the Indian house lizard during different phases of spermatogenic activity and following hypophysectomy were investigated. The concentration of total lipid, total glyceride, and total cholesterol of the testis is low during the active season (November–April) and reaches a peak when the testes are regressed (June–July). Total phospholipid is high during the spermatogenically active season and is low during the regressed season. Among the individual neutral lipids triglyceride is the major fraction while phosphatidylcholine and phosphatidylethanolamine are the major fractions of phospholipid. Hypophysectomy causes accumulation of total lipid, total glyceride, and total cholesterol; total phospholipid decreases significantly following hypophysectomy. Changes in the lipid classes following hypophysectomy are comparable to those in the testis of the intact lizards during the sexually regressed season. It is presumed that the accumulation of glyceride during the nonbreeding season and following hypophysectomy may be due to the inhibition of the enzyme phosphoryl choline transferase.

Effect of gonadotropins and testosterone on the initiation of spermatogenesis in the hypophysectomised Indian house lizard, Hemidactylus flaviviridis Ruppell.

AbstractThe action of gonadotropins (FSH, LH, PMS, and HCG) and testosterone on the initiation of spermatogenesis was studied in the Indian House Lizard Hemidactylus during the non‐breeding season after pituitary ablation. Both ovine FSH and PMS initiated spermatogenesis leading to the formation of mature spermatozoa after 45 days while LH, HCG, or TP had no stimulatory effect on the testis. Synergistic action was not observed when FSH or PMS was injected in combination with LH, TP, or HCG as evidenced by the germ cell counts in the seminiferous tubules.The androgen‐dependent sexual segment of the kidney was also fully developed in the animals treated with FSH or PMS. These results indicate that the initiation of gametogenic and androgenic functions in the testis of the Indian house lizard are dependent on an FSH‐like protein.

Effect of sex hormones on the sexual segment of kidney and other accessory reproductive organs of the Indian house lizard Hemidactylus flaviviridis Ruppell

Anabolic and androgenic steroids stimulate the development of the sexual segment of the kidney in male and female Hemidactylus gonadectomised during the period of sexual quiescence. Estrogen or progesterone has no stimulatory effect on the sexual segment in either sex. Androgens cause the stimulation of the oviduct to a secretory state. These results are discussed in relation to the action of gonadal hormones on homologous target sites in the two sexes.

Sexual segment of the kidney of the Indian house lizard, Hemidactylus flaviviridis Rüppell.

AbstractThe morphology, seasonal variation and histochemistry of the sexual segment of the Indian house lizard, Hemidactylus flaviviridis are described.The sexual segment is the hypertrophied portion of the secondary and the tertiary collecting ducts of the kidney in males. The cells of the sexual segment are columnar and are loaded with secretory granules which are predominantly localized in the apical portion. These granules are either free or occasionally clumped to form an “aggregate” towards the basement membrane and are released into the lumen by apocrine secretion. Development of the sexual segment is synchronous with the spermatogenic activity of the testis and maximum development occurs in March and April when the lizards copulate. The sexual segment is secretory from the beginning of October to the end of May and is regressed during sexual quiescence (June and July). It is not developed in females and young of both sexes in any season of the year.Histochemically, the sexual segment granules are saliva resistant and PAS positive, sudanophilic and are positive to the tests for phospholipid, choline and acid phosphatase. An intense esterase activity was localized in the mucosa of the oviduct and cloaca of the female. Sperms are mixed with sexual segment secretions and are transferred to the female during copulation. A possible role for the lipid‐rich sexual segment secretion as a source of energy for sperms in the female reproductive tract is discussed.

Phospholipids in the androgen stimulated sexual segment of the kidney of the indian house lizard, [formula omitted] rüppell

Phospholipids in the androgen stimulated sexual segment of the kidney of the indian house lizard, [formula omitted] rüppell

Phospholipids of the sexual segment of the kidney of the Indian house lizard, Hemidactylus flaviviridis Ruppell

The Indian house lizard, Hemidactylus flaviviridis breeds seasonally (1). In a sexually mature male lizard, from October to May of the following year, the secondary and tertiary collecting tubules of the kidney are hypertrophied forming the sexual segment. The development of the sexual segment is synchronous with the testicular cycle and maximum development occurs during the period when the testes are spermatogenically active (1). The sexual segment is not developed in the females in any season of the year; it is completely regressed in males during sexual quiescence (June and July). Injection of 4.0 mg of testosterone propionate over two weeks stimulated the regressed sexual segment to hypertrophy in males during quiescence and also in females (2). The apical portions of the cells of the sexual segment are loaded with granular secretions which are stained with Baker's acid haematein and phosphomolybdic acid-stannous chloride, indicating the presence of choline - containing phospholipids (1). The composition of the phospholipids of the sexual segment, which is a unique feature of the lizards and snakes, is unknown. This preliminary communication describes the isolation and quantitative estimation of phospholipids present in the sexual segment of the Indian house lizard, Hemidactylus flaviviridis Ruppell.