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result(s) for
"Snakes Life cycles."
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Dynamics of venom composition across a complex life cycle
by
Sunagar, Kartik
,
Sachkova, Maria Y
,
Columbus-Shenkar, Yaara Y
in
Animals
,
Aquatic ecosystems
,
Biochemistry
2018
Little is known about venom in young developmental stages of animals. The appearance of toxins and stinging cells during early embryonic stages in the sea anemone Nematostella vectensis suggests that venom is already expressed in eggs and larvae of this species. Here, we harness transcriptomic, biochemical and transgenic tools to study venom production dynamics in Nematostella. We find that venom composition and arsenal of toxin-producing cells change dramatically between developmental stages of this species. These findings can be explained by the vastly different interspecific interactions of each life stage, as individuals develop from a miniature non-feeding mobile planula to a larger sessile polyp that predates on other animals and interact differently with predators. Indeed, behavioral assays involving prey, predators and Nematostella are consistent with this hypothesis. Further, the results of this work suggest a much wider and dynamic venom landscape than initially appreciated in animals with a complex life cycle. Some animals produce a mixture of toxins, commonly known as venom, to protect themselves from predators and catch prey. Cnidarians – a group of animals that includes sea anemones, jellyfish and corals – have stinging cells on their tentacles that inject venom into the animals they touch. The sea anemone Nematostella goes through a complex life cycle. Nematostella start out life in eggs. They then become swimming larvae, barely visible to the naked eye, that do not feed. Adult Nematostella are cylindrical, stationary ‘polyps’ that are several inches long. They use tentacles at the end of their tube-like bodies to capture small aquatic animals. Sea anemones therefore change how they interact with predators and prey at different stages of their life. Most research on venomous animals focuses on adults, so until now it was not clear whether the venom changes along their maturation. Columbus-Shenkar, Sachkova et al. genetically modified Nematostella so that the cells that produce distinct venom components were labeled with different fluorescent markers. The composition of the venom could then be linked to how the anemones interacted with their fish and shrimp predators at each life stage. The results of the experiments showed that Nematostella mothers pass on a toxin to their eggs that makes them unpalatable to predators. Larvae then produce high levels of other toxins that allow them to incapacitate or kill potential predators. Adults have a different mix of toxins that likely help them capture prey. Venom is often studied because the compounds it contains have the potential to be developed into new drugs. The jellyfish and coral relatives of Nematostella may also produce different venoms at different life stages. This means that there are likely to be many toxins that we have not yet identified in these animals. As some jellyfish venoms are very active on humans and reef corals have a pivotal role in ocean ecology, further research into the venoms produced at different life stages could help us to understand and preserve marine ecosystems, as well as having medical benefits.
Journal Article
Snakelet to snake
by
De la Bâedoyلere, Camilla
,
De la Bâedoyلere, Camilla. Life cycles
in
Snakes Life cycles Juvenile literature.
,
Life cycles (Biology) Juvenile literature.
,
Snakes.
2010
Presents an introduction to the life cycle of a snake, from its beginning as an egg, to its life as a snakelet, to its mature life as an adult snake.
Comparative study on drug encapsulation and release kinetics in extracellular vesicles loaded with snake venom L - amino acid oxidase
by
Bakkannavar, Shankar M.
,
Pai, K. Sreedhara Ranganath
,
Bhat, Vinutha R.
in
Amino acid oxidase
,
Amino acids
,
Animals
2025
Background
This study aimed to evaluate the potential of plasma-derived extracellular vesicles (EVs) as drug delivery carriers by employing two drug-loading techniques: coincubation and freeze–thaw cycles.
Methods
EVs isolated via the polyethylene glycol (PEG) precipitation method were characterized via nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The size of the particles was 200.1 ± 66.6 nm. The isolated vesicles were loaded with 1000 µg/ml snake venom L amino acid oxidase (SVLAAO) via the coincubation method and subjected to freeze–thaw cycles to prepare a novel formulation. The encapsulation efficiency (EE) of the loaded EVs was analysed at 30 and 60 min, and in vitro drug release profiles were evaluated for both methods and kinetic model for the same was determined.
Results
The coincubation method achieved an EE of 58.08 ± 0.060% after 60 min, which was greater than that of the freeze–thaw method (55.80 ± 0.060%). Drug release studies demonstrated that 93% of the drug was released in 8.5 h by the coincubation method, whereas the freeze–thaw method resulted in faster release (99% in 6.5 h) due to membrane disruption. The best fit value (R
2
) was highest for zero order kinetics model.
Conclusion
In conclusion, the coincubation method preserves EV membrane integrity, enabling sustained drug release, making it a promising strategy for targeted drug delivery applications. This study highlights plasma-derived EVs as innovative carriers for therapeutic delivery.
Graphical Abstract
Journal Article
Snake venom phospholipase A2s exhibit strong virucidal activity against SARS-CoV-2 and inhibit the viral spike glycoprotein interaction with ACE2
2021
The COVID-19 pandemic caused by SARS-CoV-2 requires new treatments both to alleviate the symptoms and to prevent the spread of this disease. Previous studies demonstrated good antiviral and virucidal activity of phospholipase A2s (PLA2s) from snake venoms against viruses from different families but there was no data for coronaviruses. Here we show that PLA2s from snake venoms protect Vero E6 cells against SARS-CoV-2 cytopathic effects. PLA2s showed low cytotoxicity to Vero E6 cells with some activity at micromolar concentrations, but strong antiviral activity at nanomolar concentrations. Dimeric PLA2 from the viper Vipera nikolskii and its subunits manifested especially potent virucidal effects, which were related to their phospholipolytic activity, and inhibited cell–cell fusion mediated by the SARS-CoV-2 spike glycoprotein. Moreover, PLA2s interfered with binding both of an antibody against ACE2 and of the receptor-binding domain of the glycoprotein S to 293T/ACE2 cells. This is the first demonstration of a detrimental effect of PLA2s on β-coronaviruses. Thus, snake PLA2s are promising for the development of antiviral drugs that target the viral envelope, and could also prove to be useful tools to study the interaction of viruses with host cells.
Journal Article
Snake Venoms in Cancer Therapy: Past, Present and Future
by
Li, Li
,
Huang, Jianzhong
,
Lin, Yao
in
Amino acids
,
Angiotensin-converting enzyme inhibitors
,
Animals
2018
Cancer is one of the leading causes of morbidity and mortality worldwide, and the discovery of new drugs for cancer therapy is one of the most important objectives for the pharmaceutical industry. Snake venoms are complex mixtures containing different peptides, proteins, enzymes, carbohydrates and other bioactive molecules, which are secreted by the snake in the predation or defending against threats. Understanding the snake venoms may turn the toxins into a valuable source of new lead compounds in drug discovery. Captopril, the first angiotensin-converting enzyme inhibitor approved in 1981 by FDA, was designed based on the structure of a peptide isolated from the snake venom. The earliest reports about snake venoms used in cancer treatments appeared in the 1930s. Since then, numerous studies on the activities, isolations, purifications and structure elucidations of the components from snake venoms were published. The comprehensive structural and functional investigations of snake venoms would contribute to the development of novel anti-cancer drugs. Our review will focus on the past, present and the future of the studies on snake venoms in cancer target therapy.
Journal Article
Anticancer Activity of Snake Venom Against Breast Cancer: A Scoping Review
by
Kim, Eun-Jin
,
Sung, Hyun-Kyung
,
Park, Jang-Kyung
in
Animals
,
anti-cancer mechanism
,
Anticancer properties
2025
Breast cancer remains a leading cause of cancer-related mortality worldwide, necessitating innovative therapeutic approaches. This scoping review summarizes experimental evidence on the anticancer activity of snake venom and its bioactive components against breast cancer, drawing from a variety of in vitro and in vivo studies. Aimed at critically evaluating the therapeutic potential and underlying mechanisms, this review consolidates findings on venoms from multiple snake species, including both crude preparations and purified proteins or peptides, revealing a diversity of mechanisms of action. Reported effects include induction of apoptosis, generation of reactive oxygen species, disruption of cell membrane integrity, inhibition of cell proliferation and metastasis, and modulation of oncogenic signaling pathways. In vivo findings further indicate tumor growth inhibition and, in some cases, enhanced efficacy when venom-based agents are combined with nanoparticle delivery systems or conventional anticancer drugs. However, a significant proportion of evidence is limited to in vitro studies, with substantial heterogeneity in venom sources, extraction methods, dosages, and cancer models, which constrains generalizability. There is also a lack of systematic data on long-term toxicity, immunogenicity, off-target effects, pharmacokinetics, and formulation challenges. Taken together, these findings highlight snake venom-derived compounds as promising multi-targeted anticancer agents but underscore the urgent need for standardized formulations, rigorous preclinical safety assessments, and translational research to bridge the gap to clinical application. Future investigations should aim to isolate novel venom-derived compounds, refine delivery strategies, and undertake rigorous preclinical safety and pharmacokinetic studies—ultimately moving toward early-phase clinical evaluation to bridge the translational gap and assess the therapeutic potential of these agents.
Journal Article
Diversity of Hepatozoon species in wild mammals and ticks in Europe
2023
Background
Hepatozoon
spp. are tick-borne parasites causing subclinical to clinical disease in wild and domestic animals. Aim of this study was to determine
Hepatozoon
prevalence and species distribution among wild mammals and ticks in Europe.
Methods
Samples of wild mammals and ticks, originating from Austria, Bosnia and Herzegovina, Croatia, Belgium and the Netherlands, were tested with PCR to amplify a ~ 670-bp fragment of the small subunit ribosomal RNA gene.
Results
Of the 2801 mammal samples that were used for this study, 370 (13.2%) tested positive.
Hepatozoon
canis
was detected in samples of 178 animals (3 Artiodactyla, 173 Carnivora, 1 Eulipotyphia, 1 Lagomorpha),
H.
martis
in 125 (3 Artiodactyla, 122 Carnivora),
H.
sciuri
in 13 (all Rodentia),
Hepatozoon
sp. in 47 (among which
Hepatozoon
sp. Vole isolate, all Rodentia) and
H.
ayorgbor
in 4 (all Rodentia). Regarding origin, 2.9% (6/208) tested positive from Austria, 2.8% (1/36) from Bosnia and Herzegovina, 14.6% (173/1186) from Croatia and 13.9% (190/1371) from Belgium/the Netherlands. Of the 754 ticks collected, 0.0% (0/35)
Hyalomma
sp., 16.0% (4/25)
Dermacentor
spp., 0.0% (0/23)
Haemaphysalis
spp., 5.3% (24/50)
Ixodes
and 1.4% (3/221)
Rhipicephalus
spp. tested positive for
Hepatozoon
(4.2%; 32/754), most often
H.
canis
(
n
= 22).
Conclusions
Hepatozoon
canis
is most present in mammals (especially in Carnivora such as gray wolves and golden jackals) and ticks, followed by
H.
martis
, which was found merely in stone martens and pine martens. None of the rodent-associated
Hepatozoon
spp. were detected in the ticks, suggesting the possible implication of other arthropod species or non-vectorial routes in the transmission cycle of the hemoprotozoans in rodents. Our findings of
H.
canis
in ticks other than
R.
sanguineus
add to the observation that other ticks are also involved in the life cycle of
Hepatozoon
. Now that presence of
Hepatozoon
has been demonstrated in red foxes, gray wolves, mustelids and rodents from the Netherlands and/or Belgium, veterinary clinicians should be aware of the possibility of spill-over to domestic animals, such as dogs.
Graphical Abstract
Journal Article
Antitumoral Activity of Snake Venom Proteins : New Trends in Cancer Therapy
by
Zaqueo, Kayena D.
,
Marcussi, Silvana
,
Sobrinho, Juliana C.
in
Animals
,
Antineoplastic Agents - therapeutic use
,
Cancer
2014
For more than half a century, cytotoxic agents have been investigated as a possible treatment for cancer. Research on animal venoms has revealed their high toxicity on tissues and cell cultures, both normal and tumoral. Snake venoms show the highest cytotoxic potential, since ophidian accidents cause a large amount of tissue damage, suggesting a promising utilization of these venoms or their components as antitumoral agents. Over the last few years, we have studied the effects of snake venoms and their isolated enzymes on tumor cell cultures. Some in vivo assays showed antineoplastic activity against induced tumors in mice. In human beings, both the crude venom and isolated enzymes revealed antitumor activities in preliminary assays, with measurable clinical responses in the advanced treatment phase. These enzymes include metalloproteases (MP), disintegrins, L-amino acid oxidases (LAAOs), C-type lectins, and phospholipases A2 (PLA2s). Their mechanisms of action include direct toxic action (PLA2s), free radical generation (LAAOs), apoptosis induction (PLA2s, MP, and LAAOs), and antiangiogenesis (disintegrins and lectins). Higher cytotoxic and cytostatic activities upon tumor cells than normal cells suggest the possibility for clinical applications. Further studies should be conducted to ensure the efficacy and safety of different snake venom compounds for cancer drug development.
Journal Article
Pharmacological Activity of Cepharanthine
2023
Cepharanthine, a natural bisbenzylisoquinoline (BBIQ) alkaloid isolated from the plant Stephania Cephalantha Hayata, is the only bisbenzylisoquinoline alkaloid approved for human use and has been used in the clinic for more than 70 years. Cepharanthine has a variety of medicinal properties, including signaling pathway inhibitory activities, immunomodulatory activities, and antiviral activities. Recently, cepharanthine has been confirmed to greatly inhibit SARS-CoV-2 infection. Therefore, we aimed to describe the pharmacological properties and mechanisms of cepharanthine, mainly including antitumor, anti-inflammatory, anti-pathogen activities, inhibition of bone resorption, treatment of alopecia, treatment of snake bite, and other activities. At the same time, we analyzed and summarized the potential antiviral mechanism of cepharanthine and concluded that one of the most important anti-viral mechanisms of cepharanthine may be the stability of plasma membrane fluidity. Additionally, we explained its safety and bioavailability, which provides evidence for cepharanthine as a potential drug for the treatment of a variety of diseases. Finally, we further discuss the potential new clinical applications of cepharanthine and provide direction for its future development.
Journal Article