In vitro and in vivo effects of the phytohormone inhibitor fluridone against Neospora caninum infection

Neospora caninum causes abortion and stillbirth in cattle. Identification of effective drugs against this parasite remains a challenge. Previous studies have suggested that disruption of abscisic acid (ABA)-mediated signaling in apicomplexan parasites such as Toxoplasma gondii offers a new drug target. In this study, the ABA inhibitor, fluridone (FLU), was evaluated for its action against N. caninum. Production of endogenous ABA within N. caninum was confirmed by ultra-performance liquid chromatography–tandem quadruple mass spectrometry. Subsequently, FLU treatment efficacy was assessed using in vitro. Results revealed that FLU inhibited the growth of N. caninum and T. gondii in vitro (IC₅₀ 143.1 ± 43.96 μM and 330.6 ± 52.38 μM, respectively). However, FLU did not affect parasite replication at 24 h post-infection, but inhibited egress of N. caninum thereafter. To evaluate the effect of FLU in vivo, N. caninum-infected mice were treated with FLU for 15 days. FLU treatment appeared to ameliorate acute neosporosis induced by lethal parasite challenge. Together, our data shows that ABA might control egress in N. caninum. Therefore, FLU has potential as a candidate drug for the treatment of acute neosporosis.     

Fecal and Molecular Survey of Neospora caninum in Farm and Household Dogs in Mashhad Area, Khorasan Province, Iran

Neospora caninum is an important cause of abortion in dairy cattle worldwide. Dog is the definitive host for N. caninum and can infect dairy cattle. The aim of this study is to determine the prevalence of Neospora oocysts in feces of dogs from dairy farms. A total of 174 fecal samples was collected from 89 farm dogs and 85 household dogs during 2006 and 2008. Fecal samples of dogs were microscopically examined for detecting Hammondia Neospora-like oocysts (HNLO) by Mini Parasep®SF fecal parasite concentrator. HNLO were microscopically detected in 4 fecal samples (2.2%). The fecal samples with HNLO were examined by N. caninum-specific PCR. Two of the samples were positive for N. caninum. The 2 positive fecal samples were selected for inoculation to calves. Two inoculated calves were seronegative by ELISA for 4 months post-infection. This is the first report of finding N. caninum DNA in feces of farm dogs in Mashhad area, Iran.     

Effect of oregano essential oil and carvacrol on Cryptosporidium parvum infectivity in HCT-8 cells

Cryptosporidium parvum is the second leading cause of persistent diarrhea among children in low-resource settings. This study examined the effect of oregano essential oil (OEO) and carvacrol (CV) on inhibition of C. parvum infectivity in vitro. HCT-8 cells were seeded (1 × 10⁶) in 96-well microtiter plates until confluency. Cell viability and infectivity were assessed by seeding HCT-8 cell monolayers with C. parvum oocysts (1 × 10⁴) in two modalities: 1) 4 h co-culture with bioactive (0–250 μg/mL) followed by washing and incubation (48 h, 37 °C, 5% CO₂) in bioactive-free media; and 2) 4 h co-culture of C. parvum oocysts followed by washing and treatment with bioactive (0–250 μg/mL) during 48-h incubation. Cell viability was tested using Live/Dead? assay whereas infectivity was measured using C. parvum-specific antibody staining via immunofluorescence detection. Loss of cell viability was observed starting at 125 μg/mL and 60 μg/mL for OEO and CV, respectively. Neither OEO nor CV modulated the invasion of C. parvum sporozoites in HCT-8 cells. Treatment with bioactive after invasion reduced relative C. parvum infectivity in a dose-dependent manner to 55.6 ± 10.4% and 45.8 ± 4.1% at 60 and 30 μg/mL of OEO and CV, respectively. OEO and CV are potential bioactives to counteract C. parvum infection in children.     

Australian dingoes are definitive hosts of Neospora caninum

To provide objective data on the potential role of dingoes (Canis lupus dingo) in the life cycle of Neospora caninum in Australia, the production of N. caninum oocysts by experimentally infected canids was investigated. Three dingo pups raised in captivity and three domestic dogs were fed tissue from calves infected with an Australian isolate of N. caninum, Nc-Nowra. Oocysts of N. caninum, confirmed by species-specific PCR, were shed in low numbers by one dingo pup at 12-14 days p.i. The remaining animals did not shed oocysts. Furthermore, the blood from two out of three dingoes tested positive for DNA of N. caninum using PCR tests at 14 and 28 days p.i. Oocyst shedding from the intestinal tract of a dingo demonstrates that dingoes are definitive hosts of N. caninum and horizontal transmission of N. caninum from dingoes to farm animals and wildlife may occur in Australia.     

Effects of varying temperature on the reproduction and damage potential of Heterodera schachtii to Chinese cabbage (Brassica rapa pekinensis)

Heterodera schachtii is a well-known, destructive pathogen of Chinese cabbage (Brassica rapa pekinensis) in Korea, and several studies have attempted to find a potential control measure against it. This study is the first to investigate the effects of varying temperature on the reproduction and damage potential of H. schachtii to Chinese cabbage. Chinese cabbage plants were inoculated with H. schachtii at different densities (1, 2, or 4 juveniles per gram of soil) and grown under three temperature regimes: constant (15, 20, or 25 °C), increasing (10, 14, and 18 °C), and fluctuating (positive, 16.7–22.0 °C; negative, 21.5–11.5 °C). At a constant temperature after 30 days of inoculation, both Chinese cabbage and H. schachtii performed best at 20 °C. However, after 60 days of inoculation, H. schachtii had a significantly higher population at 20 °C, whereas cabbage growth was best at 25 °C. With increasing temperature, the numbers of cysts and females did not change significantly, and reached maxima at an initial temperature of 14 °C. However, the number of leaves and weights of the Chinese cabbage plants significantly differed at 14 °C. Under fluctuating temperatures, temperature decreases reduced the H. schachtii population.     

Differential susceptibility of human trophoblastic (BeWo) and uterine cervical (HeLa) cells to Neospora caninum infection

Neospora caninum is an apicomplexan parasite, closely related to Toxoplasma gondii, and causes abortion and congenital neosporosis in cattle worldwide. Trophoblast cells act in mechanisms of innate immune defense at the fetal-maternal interface and no data are available about the interaction of Neospora with human trophoblasts. Thus, this study aimed to verify the susceptibility of human trophoblastic (BeWo) compared with uterine cervical (HeLa) cell lines to N. caninum. BeWo and HeLa cells were infected with different parasite:cell ratios of N. caninum tachyzoites and analyzed at different times after infection for cell viability using thiazolyl blue tetrazole and lactate dehydrogenase assays. Both cell lines were also evaluated for cytokine production and parasite infection/replication assays when pre-treated or not with Neospora lysate antigen (NLA) or human recombinant IFN-γ. Cell viability was increased up to 48 h of infection in both types of cells, suggesting that infection could inhibit early cell death and/or induce cell proliferation. Neospora infection induced up-regulation of the macrophage migration inhibitory factor (MIF), mainly in HeLa cells, which was enhanced by cell pre-treatment by NLA or IFN-γ. Conversely, parasite infection induced down-regulation of the transforming growth factor (TGF-β), mostly in BeWo cells, which was decreased with NLA or IFN-γ pre-treatment. HeLa cells were more susceptible to Neospora infection than BeWo cells and IFN-γ pre-treatment resulted in reduced infection indices in both cell lines. Control of parasite growth was mediated by IFN-γ through an indoleamine-2,3-dioxygenase-dependent mechanism in HeLa cells alone. Based on these results, we concluded that BeWo and HeLa cells are readily infected by N. caninum, although presenting differences in susceptibility to infection, cytokine production and cell viability. Thus, these host cells can be considered in comparative approaches to understand strategies used by N. caninum to survive at the maternal-fetal interface.     

Zataria multiflora would attenuate the hepatotoxicity of long-term albendazole treatment in mice with cystic echinococcosis

Hepatic injury is the major limitation of long-term albendazole administration in patients with cystic echinococcosis (CE), which could give rise to cessation of treatment. The objective of the present study was to evaluate the protective effects of Zataria multiflora aromatic water (AW) against the hepatic injury induced by long-term albendazole treatment in mice with CE. Fifty healthy BALB/c female mice were infected intraperitoneally by injection of 1500 protoscoleces per animal. Five months after infection, the infected animals were divided into five treatment groups including Z. multiflora (40 ml/l in drinking water for 90 days), albendazole (200 mg/kg/day for 90 days), Z. multiflora + albendazole 200 (40 ml/l Z. multiflora and 200 mg/kg/day albendazole for 90 days), Z. multiflora + albendazole100 (40 ml/l Z. multiflora and 100 mg/kg/day albendazole for 90 days), and untreated (control) group. At the end of the treatment period, anesthesia was performed and blood samples were collected directly from the heart prior to euthanasia. Liver variables and oxidative stress markers were measured in the blood serum samples. A decrease in serum liver enzyme activity in the both Z. multiflora + albendazole groups was observed when compared to control, Z. multiflora and albendazole groups; however, the results for Z. multiflora + albendazole 100 were significant (p < 0.007) and superior compared to those for Z. multiflora + albendazole 200. No significant differences for oxidative stress markers were observed between the different groups. The results of the present study revealed that a combined therapy with Z. multiflora AW and albendazole is effective against hepatic injury induced by CE and/or long term albendazole administration in mice with cystic echinococcosis.     

Studies on construction of a recombinant Eimeria tenella SO7 gene expressing Escherichia coli and its protective efficacy against homologous infection

Eimeria spp. are the causative agents of coccidiosis, a major disease affecting the poultry industry. A recombinant non-antibiotic Escherichia coli that expresses the Eimeria tenella SO7 gene was constructed and its protective efficacy against homologous infection in chickens was determined. The three-day-old chickens were orally immunized with the recombinant non-antibiotic SO7 gene expressing E. coli and boosted two weeks later. Four weeks after the second immunization, the chickens were challenged with 5 × 10⁴ homologous sporulated oocysts. The protective effects of the recombinant non-antibiotic E. coli were determined by measuring body weight change, mortality, histopathology, lesion scores, oocyst counts, the specific antibody response and the frequency of CD4⁺ and CD8⁺ lymphocytes in peripheral blood. The results showed that immunization with SO7 expressing E. coli resulted in significantly improved body weight gain, reduced lesion scores and oocyst shedding in immunized chickens compared to controls. Furthermore, administration of recombinant SO7 expressing E. coli leads to a significant increase in serum antibody, CD4⁺ and CD8⁺ T cells in peripheral blood of chickens. These results, therefore, suggest that the recombinant non-antibiotic E. coli that expresses the SO7 gene is able to effectively stimulate host protective immunity as evidenced by the induction of development of both humoral and cell-mediated immune responses against homologous challenge in chickens.     

The effect of Achyranthes japonica extract on larval survival and development and oviposition behavior of Plutella xylostella L. (Lepidoptera: Plutellidae)

The extract of Achyranthes japonica was tested for effects on larval survival and development and the oviposition behavior of the diamondback moth, Plutella xylostella L. Chinese cabbage dipped in A. japonica extract solution showed 51–80% antifeedant activity for 5 days against P. xylostella larvae, and more larvae were also on untreated cabbage leaves 24 h after release. The mortality of P. xylostella larvae increased proportionally to the duration of dipping time in the extract, and both pupation and emergence rates of larvae feeding only on treated cabbage were lower than those for larvae raised on untreated or with a choice of cabbage. The 20-hydroxyecdysone (20E) concentration in leaves was approximately 549, 1232, 1275, and 1426 μg/g at 6, 12, 24, and 48 h after dipping treatment, respectively. Notably, naive females laid more eggs on untreated cabbage than on treated cabbage, and females from larvae raised on treated Chinese cabbage also preferred the non-treated leaves. Our results are in contrast to those from earlier studies using various insect models that confirmed most females prefer to lay eggs on the host type that was eaten in the larval stage (Hopkins host selection principle). Cabbage dipped in the A. japonica solution for 24 h caused 59% larval mortality and inhibited both pupation and emergence rates of the larvae when exposed to plants 15 and 22 days after planting in the field, with the 20E concentration in the treated cabbage leaves at 1600.9 ± 122.36 and 1386.8 ± 24.69 μg/g, respectively. Therefore, the biological effectiveness could be attributed to the 20E in the treated cabbage leaves.     

Fungal interaction between Trichoderma spp. and Pleurotus ostreatus on the enriched solid media with licorice Glycyrrhiza glabra root extract

The aim of this study is to investigate the antifungal activity of mycelia of Pleurotus ostreatus (white oyster mushroom) and licorice (Glycyrrhiza glabra) root extract against three undesirable fungi. They are Trichoderma spp., Trichoderma harzianum I and Trichoderma harzianum II which was tested on PSA (potato sucrose agar) medium enriched with licorice (Glycyrrhiza glabra) root extract (PSA-G media) using three concentrations (0.05, 0.10 and 0.20 g/L) in alone and dual cultures. Trichoderma spp. showed less mycelial growth of 8.75, 9.17 and 9.50 mm/day on PSA-G0.05, PSA-G0.1 and PSA-G0.2 respectively compared with 10.25 mm/day on fresh PSA (control) in dual culture. The best mycelial growth inhibition was recorded on PSA-G0.2 (14.97%) by T. harzianum II in alone culture opposite 63.72% in dual ones. The lower mycelial growth rate of T. harzianum I was 17.75 mm/day on PSA-G0.1 (0.10 g/L). In dual culture, overgrowth time of T. harzianum I had 5 days compared as approx. 6 days in alone culture. Generally, when the concentration of licorice extract increased, the mycelial growth rate of the undesirable fungi decreased. Also, all PSA-G media, especially PSA-G0.2, indicated low growth averages compared with the control (fresh PSA) against the pathogen while this concentration encourages growth of oyster mushroom. Also, this concentration reduced the density of sporulation of green molds; therefore, this concentration can be applied to reduce influence this pathogen in cultivation farm.     

Eimeria acervulina: The influence of inoculation dose on transmission between broiler chickens

The course and clinical appearance of an Eimeria species infection in chicken flocks depend on the response of an individual bird to infection and on population-dynamics of the infection in the flock. Differences in ingested numbers of oocysts may affect oocyst load in the flock and the subsequent infectious dose for not yet infected birds. To study the link between numbers of oocysts excreted by infected birds and transmission of Eimeria acervulina, experiments were carried out with 42 pairs of broiler chickens using inoculation doses with 5, 50, 500 or 50,000 sporulated oocysts. In each pair one bird was inoculated and the other bird was contact-exposed. All contact birds became infected, which occurred on average within 34 h after exposure to an inoculated bird. Although a higher inoculation dose resulted in higher oocyst excretion in inoculated and contact-infected birds, only small non-significant differences in transmission rates between groups were found.     

Middle Jurassic Ginkgo leaves from the Daohugou area,Inner Mongolia,China and their implication for palaeo-CO2 reconstruction

Well-preserved Ginkgo leaves with cuticle were collected from the Middle Jurassic Jiulongshan Formation in the Daohugou area, Inner Mongolia, China, which form the common elements in the Daohugou flora. Three new species of Ginkgo are recognized and their leaf morphology and cuticular structure are described for the first time. Two different pCO₂ proxy models were applied to reconstruct palaeo-atmospheric CO₂ concentration by using these new Ginkgo material. NLE (nearest living equivalent) suggests a semi-quantitative pCO₂ estimate as 839 ± 99 ppmv with Carboniferous standardization and 419 ± 49 ppmv with Recent standardization. While Barclay’s revised SI-pCO₂ regression suggests the estimates as 405 ± 71 ppmv. The results show that the pCO₂ estimate is higher than today’s atmospheric CO₂ concentration but lower than most of the other results on the Jurassic Period. Combined with the floristic composition, the climate at 165 Ma in the Daohugou area is inferred to be warm temperate.     

Corynebacterium heidelbergense sp. nov., isolated from the preen glands of Egyptian geese (Alopochen aegyptiacus)

Two strains (pedersoli^T and girotti) of a new species of bacteria were isolated from the preen glands of wild Egyptian geese (Alopochen aegyptiacus) from the river Neckar in southern Germany in two subsequent years. The strains were lipophilic, fastidious, Gram-positive rods and belonged to the genus Corynebacterium. Phylogenetically, the isolates were most closely related to Corynebacterium falsenii DSM 44353^T which has been found to be associated with birds before. 16S rRNA gene sequence similarity to all known Corynebacterium spp. was significantly <97%. Corresponding values of rpoB showed low levels of similarity <87% and ANIb was <73%. G + C content of the genomic DNA was 65.0 mol% for the type strain of the goose isolates, as opposed to 63.2 mol% in Corynebacterium falsenii. MALDI-TOF MS analysis of the whole-cell proteins revealed patterns clearly different from the related species, as did biochemical tests, and polar lipid profiles. We therefore conclude that the avian isolates constitute strains of a new species, for which the name Corynebacterium heidelbergense sp. nov. is proposed. The type strain is pedersoli^T (=DSM 104638^T = LMG 30044^T).     

Babesia bigemina: Advances in continuous in vitro culture using serum-free medium supplemented with insulin,transferrin, selenite,and putrescine

This study reported that Babesia bigemina (Bbig-SF) was continuously cultured in vitro in a serum-free medium supplemented with a mixture of insulin-transferrin-selenite (M-ITS) and putrescine (Pu). Firstly, the effect of five different types of basal culture media supplemented with 40% bovine serum was evaluated regarding the proliferation of the protozoan parasite. Cultures with the advanced DMEM/F12 medium (A-DMEM/F12) showed the highest percentage of parasitized erythrocytes (PPE) at 8.37%. Using A-DMEM/F12, a strain of B. bigemina (Bbig-SF) was adapted for growth in bovine serum-free medium by a sequential reduction of serum and demonstrated a maximum PPE of 7.18% in the absence of serum. The next study was the evaluation of the effect of adding four different concentrations of M-ITS to the serum-free A-DMEM/F12 medium on Bbig-SF; the optimal concentrations of M-ITS were 2000, 1100, and 1.34 mg/L, which yielded a PPE of 7.23%. Next, eight levels of Pu were evaluated on Bbig-SF cultured in serum-free A-DMEM/F12. After the addition of 0.1012 mg/L of Pu, the maximum PPE was 7.61%. When the combination of serum-free A-DMEM/F12 + M-ITS (2000, 1100, and 1.34 mg/L) + Pu (0.1012 mg/L) was evaluated, it yielded a maximum PPE of 14.80%. Finally, the combination of M-ITS + Pu in A-DMEM/F12 without serum and incorporation of a perfusion bioreactor yielded a maximum PPE of 33.45%. We concluded these culturing innovations for B. bigemina in vitro allow the optimization of small- and large-scale proliferation as a source of this protozoan parasite for future studies.     

Effects of high-temperature stress and heat shock on two root maggots, Bradysia odoriphaga and Bradysia difformis (Diptera: Sciaridae)

Bradysia odoriphaga and B. difformis (Diptera: Sciaridae) are devastating pests of vegetables, ornamentals and edible mushrooms. In Chinese chive fields, the two Bradysia species occur with similar regularities: outbreaks in spring and autumn, and population decreases in summer. Temperature may be an important factor restricting their population abundance in summer. Here, we performed a life-table study under constant high temperatures and assessed the tolerance of two Bradysia species to heat shock. Life parameters of the Bradysia species indicated slow developmental rates, and low survival rates and fecundity, when the temperature was higher than 30 °C. At 34 °C, individuals were unable to reach the adult stages from eggs. Moreover, temperatures above 36 °C showed lethal effects, decreasing their survival rates. The median lethal time (LT50) values of 4th instar B. odoriphaga and B. difformis larvae were 46.82 and 32.97 h, respectively, while the values at 38 °C were 2.12 and 1.51 h, respectively. The 4th instar larvae and pupae possessed higher thermotolerance levels than adults and eggs, indicating sensitivities to heat stress. Moreover, B. odoriphaga was more thermotolerant than B. difformis. Thus, weak thermotolerance levels may restrict their occurrences during the period of summer heat, and the difference in thermotolerance levels between the two species may be related to their regional distributions.     

Kocuria uropygioeca sp. nov. and Kocuria uropygialis sp. nov., isolated from the preen glands of Great Spotted Woodpeckers (Dendrocopos major)

Two new species of Gram-positive cocci were isolated from the uropygial glands of wild woodpeckers (Dendrocopos major) originating from different locations in Germany. A polyphasic approach confirmed the affiliation of the isolates to the genus Kocuria. Phylogenetic analysis based on the 16S rRNA gene showed high degree of similarity to Kocuria koreensis DSM 23367^T (99.0% for both isolates). However, low ANIb values of <80% unequivocally separated the new species from K. koreensis. This finding was further corroborated by DNA fingerprinting and analysis of polar lipid profiles. Furthermore, growth characteristics, biochemical tests, MALDI-TOF MS analysis, and G + C contents clearly differentiated the isolates from their known relatives. Besides, the woodpecker isolates significantly differed from each other in their whole-cell protein profiles, DNA fingerprints, and ANIb values. In conclusion, the isolated microorganisms constitute members of two new species, for which the names Kocuria uropygioeca sp. nov. and Kocuria uropygialis sp. nov. are proposed. The type strains are 36^T (DSM 101740^T = LMG 29265^T) and 257^T (=DSM 101741^T = LMG 29266^T) for K. uropygialis sp. nov. and K. uropygioeca sp. nov., respectively.     

Caulobacter zeae sp. nov. and Caulobacter radicis sp. nov., novel endophytic bacteria isolated from maize root (Zea mays L.)

Four bacterial strains designated 410^T, 441, 695^T and 736 were isolated from maize root in Beijing, P. R. China. Based on 16S rRNA gene phylogeny, the four strains formed two clusters in the genus Caulobacter. Since strain 441 was a clonal variety of strain 410^T, only three strains were selected for further taxonomic studies. The whole genome average nucleotide identity (ANI) value between strains 410^T and 695^T was 94.65%, and both strains shared less than 92.10% ANI values with their close phylogenetic neighbors Caulobacter vibrioides DSM 9893^T, Caulobacter segnis ATCC 21756^T and Caulobacter flavus CGMCC 1.15093^T. Strains 410^T and 695^T contained Q-10 as the sole ubiquinone and their major fatty acids were C_{16:0, 11-methyl C18:1ω 0}, 11-methyl C_{18: 1}ω7c, summed feature 3 (C_{16:1ω7c and/or C16:1ω 1}ω7c and/or C_{16: 1}ω6c) and summed feature 8 (C_{18:1ω7c and/or C18:1ω 1}ω7c and/or C_{18: 1}ω6c). Their major polar lipids consisted of glycolipids and phosphatidylglycerol, and phenotypic tests differentiated them from their closest phylogenetic neighbors. Based on the results obtained, it is proposed that the three strains represent two novel species, for which the names Caulobacter zeae sp. nov. (type strain 410^T = CGMCC 1.15991 = DSM 104304) and Caulobacter radicis sp. nov. (type strain 695^T = CGMCC 1.16556 = DSM 106792) are proposed.     

Survival and development of maize stem borer Chilo Partellus (Swinhoe) Lepidoptera: Crambidae on artificial diet

The Life cycle of maize stem borer, Chilo partellus (Swinhoe) was studied in in vitro conditions. Development of stem borer undergoes following stages like egg, larvae, pupa and moth. The egg incubation period ranged from 3 to 6 days, larval stage was observed in five instars. The mean value of I, II, III, IV and V instars showed 3.8 ± 0.16, 5.2 ± 0.02, 6.1 ± 0.06, 7.35 ± 1.5, and 10.12 ± 0.29 days, respectively and complete larvae period ranged from 42 to 49 days. Pupae stage was observed in 8–9 days. The pre-mating and mating period was found at 9.10 ± 1.20 and 5.14 ± 1.08 h while egg laying period in 4.1 ± 1.32 days respectively. Fecundity rate of stem borer is from 262 to 657 eggs. The life span of adult male (3-7) and female (3-8) days was observed with a mean of 6.30 ± 0.85 and 5.10 ± 0.69 days respectively. Life cycle of stem borer gets completed in 47 to 51 days. Development of quality insects in required quantities at different developmental stages and their timely supply plays an inevitable role particularly for insect-breeding resistant programs. Hence to meet these challenges we had tried to standardize an artificial diet with cost effective to rear Chilo partellus under in vitro conditions.     

Regulation of Shigella Effector Kinase OspG through Modulation of Its Dynamic Properties

Gram-negative pathogens secrete effector proteins into human cells to modulate normal cellular processes and establish a bacterial replication niche. Shigella and pathogenic Escherichia coli possess homologous effector kinases, OspG and NleH1/2, respectively. Upon translocation, OspG but not NleH binds to ubiquitin and a subset of E2 ~ Ub conjugates, which was shown to activate its kinase activity. Here we show that OspG, having a minimal kinase fold, acquired a novel mechanism of regulation of its activity. Binding of the E2 ~ Ub conjugate to OspG not only stimulates its kinase activity but also increases its optimal temperature for activity to match the human body temperature and stabilizes its labile C-terminal domain. The melting temperature (T_m) of OspG alone is only 31?°C, as compared to 41?°C to NleH1/2 homologs. In the presence of E2 ~ Ub, the T_m of OspG increases to ~ 42?°C, while Ub by itself increases the T_m to 39?°C. Moreover, OspG alone displays maximal activity at 26?°C, while in the presence of E2 ~ Ub, maximal activity occurs at ~ 42?°C. Using NMR and molecular dynamics calculations, we have identified the C-terminal lobe and, in particular, the C-terminal helix, as the key elements responsible for lower thermal stability of OspG as compared to homologous effector kinases.