Quantitative Shotgun Proteomic Analysis of Bacteria after Overexpression of Recombinant Spider Miniature Spidroin, MaSp1.

Spider silk has extraordinary mechanical properties, displaying high tensile strength, elasticity, and toughness. Given the high performance of natural fibers, one of the long-term goals of the silk community is to manufacture large-scale synthetic spider silk. This process requires vast quantities of recombinant proteins for wet-spinning applications. Attempts to synthesize large amounts of native size recombinant spidroins in diverse cell types have been unsuccessful. In these studies, we design and express recombinant miniature black widow MaSp1 spidroins in bacteria that incorporate the N-terminal and C-terminal domain (NTD and CTD), along with varying numbers of codon-optimized internal block repeats. Following spidroin overexpression, we perform quantitative analysis of the bacterial proteome to identify proteins associated with spidroin synthesis. Liquid chromatography with tandem mass spectrometry (LC MS/MS) reveals a list of molecular targets that are differentially expressed after enforced mini-spidroin production. This list included proteins involved in energy management, proteostasis, translation, cell wall biosynthesis, and oxidative stress. Taken together, the purpose of this study was to identify genes within the genome of Escherichia coli for molecular targeting to overcome bottlenecks that throttle spidroin overexpression in microorganisms.

The functional microclimate of an urban arthropod pest: Urban heat island temperatures in webs of the western black widow spider.

Urbanization alters natural landscapes and creates unique challenges for urban wildlife. Similarly, the Urban Heat Island (UHI) effect can produce significantly elevated temperatures in urban areas, and we have a relatively poor understanding of how this will impact urban biodiversity. In particular, most studies quantify the UHI using broad-scale climate data rather than assessing microclimate temperatures actually experienced by organisms. In addition, studies often fail to address spatial and temporal complexities of the UHI. Here we examine the thermal microclimate and UHI experienced in the web of Western black widow spiders (Latrodectus hesperus), a medically-important, superabundant urban pest species found in cities across the Western region of North America. We do this using replicate urban and desert populations across an entire year to account for seasonal variation in the UHI, both within and between habitats. Our findings reveal a strong nighttime, but no daytime, UHI effect, with urban spider webs being 2-5 °C warmer than desert webs at night. This UHI effect is most prominent during the spring and least prominent in winter, suggesting that the UHI need not be most pronounced when temperatures are most elevated. Urban web temperatures varied among urban sites in the daytime, whereas desert web temperatures varied among desert sites in the nighttime. Finally, web temperature was significantly positively correlated with a spider's boldness, but showed no relationship with voracity towards prey, web size, or body condition. Understanding the complexities of each organism's thermal challenges, the "functional microclimate", is crucial for predicting the impacts of urbanization and climate change on urban biodiversity and ecosystem functioning.

Reversible Myocarditis Following Black Widow Spider (Latrodectus spp.) Bite in Egypt: A case report.

Black widow spiders (BWSs) are poisonous spiders of the Arthropoda phylum that live in the Mediterranean region. The effects of BWS bites ranges from local damage to systemic manifestations including paresthesia, stiffness, abdominal cramps, nausea, vomiting, headache, anxiety, hypertension and tachycardia. However, cardiac involvement following a BWS bite is uncommon. We report a 35-year-old male patient who presented to a tertiary hospital in Menoufia, Egypt, in 2019 and developed acute pulmonary oedema with electrocardiogram (ECG) changes that showed ST elevation in leads I and aVL with reciprocal ST segment depression in infero-lateral leads with elevated cardiac biomarkers. Echocardiography showed regional wall motion abnormalities with an impaired ejection fraction of 42%. The condition was reversible after one week of supportive treatment and the patient was discharged from the hospital with normal electrocardiogram, ejection fraction and negative cardiac markers. A routine cardiac evaluation, serial ECG, serial cardiac markers and echocardiography should be considered for any patient exposed to a BWS bite for detection of any potentially fatal cardiac abnormalities.

Improved Black Widow Spider Optimization Algorithm Integrating Multiple Strategies.

The black widow spider optimization algorithm (BWOA) had the problems of slow convergence speed and easily to falling into local optimum mode. To address these problems, this paper proposes a multi-strategy black widow spider optimization algorithm (IBWOA). First, Gauss chaotic mapping is introduced to initialize the population to ensure the diversity of the algorithm at the initial stage. Then, the sine cosine strategy is introduced to perturb the individuals during iteration to improve the global search ability of the algorithm. In addition, the elite opposition-based learning strategy is introduced to improve convergence speed of algorithm. Finally, the mutation method of the differential evolution algorithm is integrated to reorganize the individuals with poor fitness values. Through the analysis of the optimization results of 13 benchmark test functions and a part of CEC2017 test functions, the effectiveness and rationality of each improved strategy are verified. Moreover, it shows that the proposed algorithm has significant improvement in solution accuracy, performance and convergence speed compared with other algorithms. Furthermore, the IBWOA algorithm is used to solve six practical constrained engineering problems. The results show that the IBWOA has excellent optimization ability and scalability.

Egg Case Protein 3: A Constituent of Black Widow Spider Tubuliform Silk.

Spider silk has outstanding mechanical properties, rivaling some of the best materials on the planet. Biochemical analyses of tubuliform silk have led to the identification of TuSp1, egg case protein 1, and egg case protein 2. TuSp1 belongs to the spidroin superfamily, containing a non-repetitive N- and C-terminal domain and internal block repeats. ECP1 and ECP2, which lack internal block repeats and sequence similarities to the highly conserved N- and C-terminal domains of spidroins, have cysteine-rich N-terminal domains. In this study, we performed an in-depth proteomic analysis of tubuliform glands, spinning dope, and egg sacs, which led to the identification of a novel molecular constituent of black widow tubuliform silk, referred to as egg case protein 3 or ECP3. Analysis of the translated ECP3 cDNA predicts a low molecular weight protein of 11.8 kDa. Real-time reverse transcription-quantitative PCR analysis performed with different silk-producing glands revealed ECP3 mRNA is predominantly expressed within tubuliform glands of spiders. Taken together, these findings reveal a novel protein that is secreted into black widow spider tubuliform silk.

Silently Suffering: A Pediatric Black Widow Spider Envenomation.

BACKGROUND: Black widow spiders are distributed worldwide and, although rarely fatal, account for significant morbidity. Diagnosis can be challenging, and children are at risk of increased morbidity due to their small size. CASE REPORT: We present a case of a 3-year-old boy who was brought to our emergency department because of sudden ear pain followed by labored breathing, abdominal pain, refusal or inability to speak, and grunting respirations. A black widow spider bite was suspected based on additional history obtained, and the spider was found in his helmet, confirming the diagnosis. The patient had progressive respiratory distress and somnolence and was intubated and transferred to a local pediatric intensive care unit. Antivenom was not initially available and eventually declined by the family. The child received supportive care and recovered after several days. Why Should an Emergency Physician Be Aware of This? This case illustrates the potentially deadly effects a black widow envenomation could cause in a child, and that bite location can affect the constellation of symptoms. It is a reminder that toxins, including that of the black widow spider, should be on the differential for acute abdominal pain, especially with autonomic features.

[Gene cloning, heterologous expression and activity identification of latroeggtoxin-â ¥].

One of the distinct characters of Latrodectus tredecimguttatus is that its toxic components exist not only in the venomous glands, but also in the tissues outside the venomous glands and even in the eggs. Investigation on the toxins outside the venomous glands can deepen our understanding of spider toxins and discover new lead molecules with important application prospects. In order to explore the low-abundance proteinaceous toxins in the L. tredecimguttatus eggs, we used bioinformatic strategies to mine a gene sequence encoding a peptide toxin from the transcriptome of L. tredecimguttatus eggs, and then heterologously expressed the gene successfully with a 3'-RACE combined with nest PCR strategy. Biological activity analyses indicated that the expressed peptide toxin, named latroeggtoxin-Ⅵ (LETX-Ⅵ), could inhibit Na⁺ channel currents in ND7/23 cells and promote dopamine release from PC12 cells, without obvious toxicity against Periplaneta americana and bacteria as well as fungi including Staphylococcus aureus and Candida albicans, demonstrating that LETX-Ⅵ is a mammal-specific neurotoxin with a potential application prospect in development of the tool reagents for neurobiological study and the drugs for treating related diseases.

Structural Characterization of Black Widow Spider Dragline Silk Proteins CRP1 and CRP4.

Spider dragline silk represents a biomaterial with outstanding mechanical properties, possessing high-tensile strength and toughness. In black widows at least eight different proteins have been identified as constituents of dragline silk. These represent major ampullate spidroins MaSp1, MaSp2, MaSp', and several low-molecular weight cysteine-rich protein (CRP) family members, including CRP1, CRP2, and CRP4. Molecular modeling predicts that CRPs contain a cystine slipknot motif, but experimental evidence to support this assertion remains to be reported. To advance scientific knowledge regarding CRP function, we recombinantly expressed and purified CRP1 and CRP4 from bacteria and investigated their secondary structure using circular dichroism (CD) under different chemical and physical conditions. We demonstrate by far-UV CD spectroscopy that these proteins contain similar secondary structure, having substantial amounts of random coil conformation, followed by lower levels of beta sheet, alpha helical and beta turn structures. CRPs are thermally and pH stable; however, treatment with reagents that disrupt disulfide bonds impact their structural conformations. Cross-linking mass spectrometry (XL-MS) data also support computational models of CRP1. Taken together, the chemical and thermal stability of CRPs, the cross-linking data, coupled with the structural sensitivity to reducing agents, are experimentally consistent with the supposition CRPs are cystine slipknot proteins.

Comparative proteomic analysis to probe into the differences in protein expression profiles and toxicity bases of Latrodectus tredecimguttatus spiderlings and adult spiders.

The early reports and our previous work confirmed the existence of the toxic proteinaceous components in the body of the L. tredecimguttatus newborn and adult spiders. For revealing the differences in the protein expression profiles and toxicity bases of the spiders at different developmental stages, the spiderling and adult spider proteins were comparatively analyzed using a proteomic strategy. Totals of 429 and 958 proteins were identified from the spiderlings and adult spiders, respectively, with 239 proteins being identified from both of them. Although some similarities between the spiderling and adult spider proteomes exist, there are obvious differences between the two proteomes in size, complexity, molecular weight (MW) distribution, acid-base property, and hydropathicity, etc. Gene ontology (GO) analysis demonstrates that, comparing based on the percentages of proteins, the spiderling and adult spider proteins have generally similar distribution profiles with respect to the subcellular localization, molecular function and biological process. However, there are still some differences between these two sets of proteins in some classifications of the three GO categories. For the adult spiders, latrotoxins together with other toxins and toxin-like proteins, etc. constitute their toxicity basis, whereas the toxicity of the spiderlings depends mainly on the synergistic action of atypical latrotoxins and toxin-like proteins, most of which are different from those of the adult spiders, demonstrating that the spiders at different developmental stages have largely different toxicity mechanisms.

Ovarian Transcriptomic Analyses in the Urban Human Health Pest, the Western Black Widow Spider.

Due to their abundance and ability to invade diverse environments, many arthropods have become pests of economic and health concern, especially in urban areas. Transcriptomic analyses of arthropod ovaries have provided insight into life history variation and fecundity, yet there are few studies in spiders despite their diversity within arthropods. Here, we generated a de novo ovarian transcriptome from 10 individuals of the western black widow spider (Latrodectus hesperus), a human health pest of high abundance in urban areas, to conduct comparative ovarian transcriptomic analyses. Biological processes enriched for metabolism-specifically purine, and thiamine metabolic pathways linked to oocyte development-were significantly abundant in L. hesperus. Functional and pathway annotations revealed overlap among diverse arachnid ovarian transcriptomes for highly-conserved genes and those linked to fecundity, such as oocyte maturation in vitellogenin and vitelline membrane outer layer proteins, hormones, and hormone receptors required for ovary development, and regulation of fertility-related genes. Comparative studies across arachnids are greatly needed to understand the evolutionary similarities of the spider ovary, and here, the identification of ovarian proteins in L. hesperus provides potential for understanding how increased fecundity is linked to the success of this urban pest.

Juvenile social experience generates differences in behavioral variation but not averages.

Developmental plasticity is known to influence the mean behavioral phenotype of a population. Yet, studies on how developmental plasticity shapes patterns of variation within populations are comparatively rare and often focus on a subset of developmental cues (e.g., nutrition). One potentially important but understudied developmental experience is social experience, as it is explicitly hypothesized to increase variation among individuals as a way to promote "social niches." To test this, we exposed juvenile black widow spiders (Latrodectus hesperus) to the silk of conspecifics by transplanting them onto conspecific webs for 48 h once a week until adulthood. We also utilized an untouched control group as well as a disturbed group. This latter group was removed from their web at the same time points as the social treatment, but was immediately placed back on their own web. After repeatedly measuring adult behavior and web structure, we found that social rearing drove higher or significant levels of repeatability relative to the other treatments. Repeatability in the social treatment also decreased in some traits, paralleling the decreases observed in the disturbed treatments. Thus, repeated juvenile disturbance may decrease among-individual differences in adult spiders. Yet, social rearing appeared to override the effect of disturbance in some traits, suggesting a prioritization effect. The resulting individual differences were maintained over at least one-third of the adult lifespan and thus appear to represent stable, canalized developmental effects and not temporal state differences. These results provide proximate insight into how a broader range of developmental experiences shape trait variation.

A Review of the Chemistry, Pesticide Use, and Environmental Fate of Sulfur Dioxide, as Used in California.

Sulfur dioxide (SO2) is an atmospheric pollutant that is moderately persistent in the atmosphere and highly water soluble. When applied as a pesticide, SO2 may be transported, deposited, or transformed in various chemical reactions. SO2 participates in the sulfur biogeochemical cycle, which involves complex reactions of sulfur-containing compounds between abiotic and biotic components of ecosystems. The main degradation route of SO2 is atmospheric oxidation, and sulfur oxides may undergo long-distance transport prior to removal from the atmosphere by wet or dry deposition. According to the Pesticide Use Reporting (PUR) database maintained by the California Department of Pesticide Regulation (DPR), SO2 use in California from 2010 to 2015 was primarily for fumigations (96%), including treatments of postharvest grape products and winery equipment sterilizations. Other site uses contributed less than 5% of reported statewide SO2 use from 2010 to 2015. A slight increasing trend in use of SO2 as a pesticide was observed from 2010 to 2015, with the highest reported uses of SO2 within California counties during the months of July-November. Although the primary sources of SO2 in the environment are anthropogenic emissions from the combustion of fossil fuels, emissions of SO2 from pesticide uses have the potential to contribute to the environmental and public welfare impacts of SO2 pollution. Oxidation of atmospheric SO2 may contribute to the negative environmental and public welfare impacts of acid rain, which include toxicity to aquatic organisms, fish, and terrestrial vegetation, and corrosion of man-made materials.

Cytotoxic and apoptotic activities of black widow spiderling extract against HeLa cells.

Black widow spiders contain toxic components not only in the venom glands but also in other parts of the spider body, including the legs and abdomen. Additionally, both the eggs and newborn spiderlings of the black widow spider contain venom. It is important to investigate their potential effects on cancer cells. In the present study, the effects of newborn black widow spiderling extract on human HeLa cells were evaluated in vitro. When applied at different concentrations, the total extract decreased HeLa cell viability in a dose-dependent manner, with an IC50 value of 158 µg/ml. Flow cytometry indicated that treatment of HeLa cells with the total extract of the spiderlings induced apoptosis in HeLa cells in a dose-dependent manner and led to cell cycle arrest in the S-phase. Additionally, application of the total extract at different concentrations increased apoptosis-related caspase 3 activity in a dose-dependent manner. HeLa cells treated with the total extract appeared to be morphologically changed, exhibiting membrane blebbing, nuclear fragmentation and condensation of chromatin. Further separation and activity screening demonstrated that the cytotoxic and apoptotic activities of the total extract were attributable mainly to its high molecular mass proteins, one of which was purified and characterized to determine its anti-tumor activities on HeLa cells. The results of the present study therefore have expanded understanding regarding the effect of spider toxins on cancer cells and suggested that components of black widow spiderlings may be developed as a promising novel agent to treat cancer.

Black widow spider bites experience from tertiary care center in Saudi Arabia.

INTRODUCTION: Black widow spiders are one of the most poisonous species to humans; there are more than 30 species of widow spiders in the globe but good thing that not all of them are dangerous. Some of these spiders produce toxic venoms, which cause broad spectrum of clinical manifestations including skin lesions, neurotoxicity, cardiac toxicity and death in some occasions. In Saudi Arabia there were no much reports of black widow spider bites apart from the case series by BUCUR and his group in ALBAHA region. SETTINGS: In 2 years period a total of 8 patients were presented to the emergency departments diagnosed to have black widow spider bites based on description by the patients. RESULTS: 100 % of the cohort were males, aged between 25-58 years. The time between bite and presentation to emergency room was one hour in average (30 min to 4 hours). 75% occured during summer season. All of them 100% had one bite only and reported the bite to be at nighttime in 75% of the times. The average pain score at presentation was 4 /10.100% of the bites were in the lower extremities and almost all progressed to have lower back pain. Three patients had gastrointestinal tract manifestation in form of abdominal cramps and nausea. One had bilateral ptosis, none of them had cardiac or pulmonary complications. The outcome was excellent in all patients and the average of hospital stay was 2.5 days (1-5).

Latrodectismo. Caso clínico y revisión de la literatura / Latrodectism Case report and review of literature

El latrodectismo es un cuadro clínico causado por la mordedura de una araña del género Latrodectus spp., ampliamente distribuido en todo Chile continental. Generalmente las mordeduras se asocian a faenas agrícolas. El veneno del género Latrodectus contiene α-latrotoxina, una neurotoxina que actúa a nivel presináptico del sistema nervioso autónomo aumentando la liberación de acetilcolina. El cuadro clínico es inespecífico y hasta en un tercio de los casos ocurren síntomas sistémicos. El diagnóstico es clínico y depende del antecedente de la mordedura por una araña con un cuadro clínico compatible. El pronóstico es favorable: se reporta una letalidad entre 0 y 6 por ciento. El manejo es esencialmente sintomático, principalmente analgésico. Presentamos el caso de un hombre de 62 años, proveniente de Santa Cruz, VI región, trabajador en una plantación de trigo. Consultapor dolor torácico asociado a mialgias generalizadas y diaforesis. Por sospecha de latrodectismo, se administra neostigmina con buena respuesta clínica.(AU)

Latrodectism is a clinical entity caused by the bite of a spider of the genus Latrodectus spp. widely distributed throughout continental Chile. Generally, bites are associated with agricultural activities. The venom of spiders of the genus Latrodectus contains α-latrotoxin, a neurotoxin that acts at the presynaptic level of the autonomic nervous system, this way increases the release of acetylcholine. The clinical manifestations are non-specific and systemic symptoms occur in up to one-third of the cases. The diagnosis is clinical and depends on the history of being bitten by a spider with a compatible clinical presentation. The prognosis is favorable: a lethality between 0 and 6 percent has been reported. The clinical management is essentially symptomatic, mainly analgesic. We present the case of a 62-year-old man from Santa Cruz, VI region, working in a wheat farm. He attends the emergency service with chest pain associated with generalized myalgias and diaphoresis. On suspicion of latrodectism, neostigmine is administered with goodclinical response. (AU)

Comprehensive Proteomic Analysis of Spider Dragline Silk from Black Widows: A Recipe to Build Synthetic Silk Fibers.

The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2). Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA) gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID), electron transfer dissociation (ETD), and high energy collision dissociation (HCD) to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1), widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4), cysteine-rich secretory protein 3 (CRISP3), fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers.

[Neurotoxic manifestations of black widow spider envenomation in paediatric patients]. / Manifestaciones de neurotoxicidad en el envenenamiento por mordedura de araña «viuda negra¼ en edades pediátricas.

INTRODUCTION: Envenomation by black widow spiders manifests clinically with signs of neurotoxicity in paediatric patients. OBJECTIVE: Identify typical neurological signs and symptoms in paediatric patients of different ages, and describe treatment and outcomes in a paediatric hospital in northwest Mexico. MATERIAL AND METHODS: We reviewed 70 clinical records of patients hospitalised due to black widow spider bite between 1978 and 2014. We divided the total into 2 groups: Group 1, infants and preschool children; and Group 2, school-age children and adolescents. The demographic variables were age, sex, birthplace, place where envenomation occurred, body part(s) affected, degree of envenomation according to signs and symptoms, treatment, clinical outcome, and statistical differences. RESULTS: Boys accounted for 61.4% of all cases, and infants younger than one year old made up 14.2%. Most patients (70%) were bitten by the spider at home; the anatomical areas most frequently affected were the legs, neck, thorax, and abdomen. The neurological signs and symptoms displayed by Group 1 were irritability, constant crying, sialorrhoea, nausea, tachycardia, arrhythmias, fatigue when walking, agitation, muscle spasms paraesthesia, tetany, seizures, and nystagmus. Signs in Group 2 included localized pain, headache, sialorrhoea, paraesthesia, profuse sweating, anxiety, muscle weakness, muscle spasms, and fine tremor. The predominant autonomic sign in Group 1 was sialorrhoea (P<.0001) and in Group 2, paraesthesia (P<.0001). Patients who received Fab antivenom treatment displayed better outcomes and shorter hospital stays than those who did not. No deaths were reported. CONCLUSIONS: The neurological signs and symptoms caused by black widow spider bite are predominantly autonomic, and identifying them permits early diagnosis and more effective treatment.

Physiological and biochemical analysis to reveal the molecular basis for black widow spiderling toxicity.

The early research found that the spiderlings of black widow spider (Latrodectus tredecimguttatus) exhibited obvious toxicity to animals. The present work performed a systematical analysis of the aqueous extract of newborn black widow spiderlings. The extract was shown to contain 69.42% of proteins varying in molecular weights and isoelectric points. Abdominal injection of the extract into mice and cockroaches caused obvious poisoning symptoms as well as death, with LD50 being 5.30 mg/kg in mice and 16.74 µg/g in Periplaneta americana. Electrophysiological experiments indicated that the extract at a concentration of 10 µg/mL could completely block the neuromuscular transmission in isolated mouse nerve-hemidiaphragm preparations within 21 ± 1.5 min, and 100 µg/mL extract could inhibit a certain percentage of voltage-activated Na⁺, K⁺, and Ca²âº channel currents in rat dorsal root ganglion neurons. These results demonstrate that the spiderlings are rich in neurotoxic components, which play important roles in the spiderling toxicity.

Isolation and identification of a sodium channel-inhibiting protein from eggs of black widow spiders.

The eggs of black widow spider (L. tredecimguttatus) have been demonstrated to be rich in biologically active components that exhibit great research value and application foreground. In the present study, a protein toxin, named Latroeggtoxin-II, was isolated from the eggs using the combination of gel filtration, ion exchange chromatography and reversed-phase high performance liquid chromatography. Electrospray mass spectrometric analysis indicated that the molecular weight of the protein was 28.69 kDa, and Edman degradation revealed that its N-terminal sequence was ESIQT STYVP NTPNQ KFDYE VGKDY-. After being abdominally injected into mice and P. americana, the protein could make the animals especially P. americana display a series of poisoning symptoms. Electrophysiological experiments demonstrated that the protein could selectively inhibit tetrodotoxin-resistant Na(+) channel currents in rat dorsal root ganglion neurons, without significant effect on the tetrodotoxin-sensitive Na(+) channel currents. Using multiple proteomic strategies, the purified protein was shown to have only a few similarities to the existing proteins in the databases, suggesting that it was a novel protein isolated from the eggs of black widow spiders.

Poisonous Spiders: Bites, Symptoms, and Treatment; an Educational Review.

More than 40,000 species of spiders have been identified in the world. Spider bites is a common problem among people, however few of them are harmful but delay in treatment can cause death. Since the spider bites are risk full to human, they should be taken seriously, especially in endemic areas. Our objective in this review was to study about poisonous spiders and find out treatments of them. Therefore, we collected related articles from PubMed database and Google Scholar. Three important syndromes caused by spider bites are loxoscelism, latrodectism and funnel web spider syndrome. Many treatments are used but much more studies should have done to decrease the mortality. In this review, we describes different venomous spiders according to their appearance, symptoms after their bites and available treatments.