b microti strains  (ATCC)

Journal: Frontiers in Microbiology

Article Title: Apoptosis and autophagy promote Babesia microti infection in tick midguts: insights from transcriptomic and functional RNAi studies

doi: 10.3389/fmicb.2025.1632974

Figure Lengend Snippet: B. microti presence and differential gene expression in B. microti -infected tick midguts. (A) B. microti presence in the engorged nymph midgut ( n = 3). (B) Principal component analysis (PCA) of gene expression profiles. (C) Upregulated and downregulated genes are indicated in red and blue, respectively. IE0 d : Infected B. microti at 0 day post-engorgement; IE1 d : Infected B. microti at 1 d post-engorgement; IE4 d : Uninfected B. microti at 4 d post-engorgement; UE0 d : Uninfected B. microti at 0 day post-engorgement; UE4 d: Uninfected B. microti at 4 d post-engorgement.

Article Snippet: Cryopreserved B. microti strains (ATCC PRA-99TM) were rapidly thawed in a 37 °C water bath, and 500 μL of the suspension was administered intraperitoneally into specific pathogen-free BALB/c mice.

Techniques: Gene Expression, Infection

Journal: Frontiers in Microbiology

Article Title: Apoptosis and autophagy promote Babesia microti infection in tick midguts: insights from transcriptomic and functional RNAi studies

doi: 10.3389/fmicb.2025.1632974

Figure Lengend Snippet: GO enrichment analysis of DEGs in tick midguts at 0 (A) and 4 days (B) post-engorgement. Bar plots show significantly enriched GO terms across three functional categories: Biological Process (BP); Molecular Function (MF); and Cellular Component (CC). The x-axis represents the number of DEGs associated with each GO term, while the y-axis indicates the corresponding GO terms. Upregulated terms are shown in yellow, while downregulated terms are in blue. IE0 d : Infected B. microti at 0 day post-engorgement; IE4 d : Infected B. microti at 4 d post-engorgement; UE0 d : Uninfected B. microti at 0 day post-engorgement; UE4 d : Uninfected B. microti at 4 d post-engorgement.

Article Snippet: Cryopreserved B. microti strains (ATCC PRA-99TM) were rapidly thawed in a 37 °C water bath, and 500 μL of the suspension was administered intraperitoneally into specific pathogen-free BALB/c mice.

Techniques: Functional Assay, Infection

Journal: Frontiers in Microbiology

Article Title: Apoptosis and autophagy promote Babesia microti infection in tick midguts: insights from transcriptomic and functional RNAi studies

doi: 10.3389/fmicb.2025.1632974

Figure Lengend Snippet: Transcriptional activation of apoptosis and autophagy pathways in tick midguts following B. microti infection (A) qRT-PCR analysis of apoptosis-related genes ( caspase-7, caspase-8 , and caspase-9 ) and in H. longicornis nymphs at day 0 post-engorgement ( n = 3). (B) autophagy-related genes ( ATG5, ATG6, ATG8, ATG12 ) in H. longicornis nymphs at day 0 post-engorgement ( n = 3). B. microti -infected midguts (green) exhibited significant upregulation of apoptosis- and autophagy-related genes compared with uninfected controls (red). Data are presented as the mean ± standard error. P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001 , differential gene expression analysis determined using Student's t test.

Article Snippet: Cryopreserved B. microti strains (ATCC PRA-99TM) were rapidly thawed in a 37 °C water bath, and 500 μL of the suspension was administered intraperitoneally into specific pathogen-free BALB/c mice.

Techniques: Activation Assay, Infection, Quantitative RT-PCR, Gene Expression

Journal: Frontiers in Microbiology

Article Title: Apoptosis and autophagy promote Babesia microti infection in tick midguts: insights from transcriptomic and functional RNAi studies

doi: 10.3389/fmicb.2025.1632974

Figure Lengend Snippet: B. microti infection induces apoptosis and autophagy in tick midguts. (A) Apoptosis assessment in midgut tissues of engorged ticks by TUNEL staining ( n = 3). Nuclei were counterstained with DAPI (blue) and apoptotic cells were labeled with TUNEL (red). Quantitative analysis of fluorescence intensity (right) showed significantly elevated apoptosis levels in B. microti -infected ticks. (B) TEM revealed autophagy activation in B. microti -infected ticks, indicated by characteristic double- or multi-membrane vesicles enclosing cytoplasmic contents (arrows, n = 3). This experiment was conducted concurrently with the mitochondrial observations reported by our previous publication, utilizing the same biological samples for autophagosome observation . UE0 d: Uninfected B. microti at 0 day post-engorgement; IE0 d : infected B. microti at 0 day post-engorgement. Data are presented as the mean ± standard error. P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001 . differential gene expression analysis determined using Student's t test.

Article Snippet: Cryopreserved B. microti strains (ATCC PRA-99TM) were rapidly thawed in a 37 °C water bath, and 500 μL of the suspension was administered intraperitoneally into specific pathogen-free BALB/c mice.

Techniques: Infection, TUNEL Assay, Staining, Labeling, Fluorescence, Activation Assay, Membrane, Gene Expression

Journal: Frontiers in Microbiology

Article Title: Apoptosis and autophagy promote Babesia microti infection in tick midguts: insights from transcriptomic and functional RNAi studies

doi: 10.3389/fmicb.2025.1632974

Figure Lengend Snippet: RNAi of caspase-7 and caspase-9 reduces B. microti infection in H. longicornis . (A) qPCR analysis of RNAi efficiency for caspase-7 and caspase-9 in engorged nymphs ( n = 3). (B) qRT-PCR analysis demonstrated a significant reduction in B. microti load following caspase-7 ( n = 9) and caspase-9 ( n = 6) gene silencing in H. longicornis nymphs compared with luciferase dsRNA controls ( n = 9 for caspase-7 comparison; n = 8 for caspase-9 comparison). Data are presented as the mean ± standard error. * P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001 , differential gene expression analysis determined using Student's t test; B. microti load analysis determined using two-tailed Mann-Whitney U test.

Article Snippet: Cryopreserved B. microti strains (ATCC PRA-99TM) were rapidly thawed in a 37 °C water bath, and 500 μL of the suspension was administered intraperitoneally into specific pathogen-free BALB/c mice.

Techniques: Infection, Quantitative RT-PCR, Luciferase, Comparison, Gene Expression, Two Tailed Test, MANN-WHITNEY

Journal: Frontiers in Microbiology

Article Title: Apoptosis and autophagy promote Babesia microti infection in tick midguts: insights from transcriptomic and functional RNAi studies

doi: 10.3389/fmicb.2025.1632974

Figure Lengend Snippet: Autophagy promotes B. microti infection in H. longicornis . (A) Differential analysis of B. microti load in ticks treated with rapamycin (autophagy inducer, n = 18), 3-methyladenine (autophagy inhibitor, n = 20) and DMSO ( n = 15 for rapamycin comparison; n = 12 for 3-methyladenine comparison). (B) qPCR analysis assessing RNAi efficiency for ATG5 genes in engorged tick nymphs ( n = 3). (C) qRT-PCR analysis revealed that ATG5 knockdown significantly reduced B. microti acquisition in H. longicornis nymphs ( n = 9). Data are presented as the mean ± standard error. * P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001 , differential gene expression analysis determined using Student's t test; B. microti load analysis determined using two-tailed Mann-Whitney U test.

Article Snippet: Cryopreserved B. microti strains (ATCC PRA-99TM) were rapidly thawed in a 37 °C water bath, and 500 μL of the suspension was administered intraperitoneally into specific pathogen-free BALB/c mice.

Techniques: Infection, Comparison, Quantitative RT-PCR, Knockdown, Gene Expression, Two Tailed Test, MANN-WHITNEY

Journal: Microbiology Spectrum

Article Title: Long-term survival of Babesia microti and Borrelia burgdorferi in C3H/HeJ mice and their effect on Lyme arthritis and babesiosis manifestations

doi: 10.1128/spectrum.00252-25

Figure Lengend Snippet: Co-infection experiment plan in C3H/HeJ mice and euthanasia time points. We carried out an infection experiment using 5-week-old C3H/HeJ mice for 4 months to determine if B. burgdorferi or B. microti ( Bm ) persists long term in co-infected rodent hosts and to ascertain their reciprocal effects on the disease’s pathogenesis at short- and long-term infection. C3H/HeJ female and/or male mice were injected with 100 µL containing 10 4 Bm- iRBC subcutaneously (sc) in the left flank and/or infected with 10 3 N40 spirochetes sc in the right flank and organized into four experimental groups: (i) N40; (ii) N40 + Bm co-infection; (iii) Bm; (iv) Naïve. Parasitemia determination by microscopy and IVIS were used at different time points to determine B. microti and N40 burdens, respectively. This experiment was conducted three times, first in both sexes of mice and then repeated two more times only in female mice to confirm the results.

Article Snippet: We investigated the effect of co-infection using our bioluminescent B. burgdorferi N40D10/E9 derivative (N40 henceforth) ( ) and B. microti gray strain (ATCC 30221) in both sexes of C3H/HeJ mice in this study to assess pathogenesis from the acute phase of infection (2 weeks) to long-term infection (16 weeks).

Techniques: Infection, Injection, Microscopy

Journal: Microbiology Spectrum

Article Title: Long-term survival of Babesia microti and Borrelia burgdorferi in C3H/HeJ mice and their effect on Lyme arthritis and babesiosis manifestations

doi: 10.1128/spectrum.00252-25

Figure Lengend Snippet: Comparative analysis of B. microti parasitemia and splenomegaly and B. burgdorferi colonization in male and female C3H/HeJ mice. ( A ) C3H/HeJ female and male mice were inoculated sc in the left flank with 10 4 Bm- infected red blood cells (iRBCs) alone or together with 10 3 N40 spirochetes (inoculated sc in the right flank). B. microti parasitemia was determined in blood smears stained with Giemsa stain and by calculation of the average percentage of iRBC of total RBCs observed in 25 microscopic fields using oil immersion at 1,000×. ( B ) After terminal bleeding, mice were euthanized by CO 2 asphyxiation at 16 weeks post-infection. Spleens were aseptically harvested and weighed to determine splenomegaly. ( C ) The effect of Bm infection on N40 colonization was determined in both sexes of mice infected with N40 and/or Bm using IVIS-200 after intraperitoneal injection of 200 µL of 30 mg/mL D-luciferin at 2 weeks post-infection. The presence of B. burgdorferi N40 strain was visualized in different tissues measured by bioluminescent radiance as a semi-quantitative indicator of colonization by spirochetes. Parasitemia and splenomegaly data are represented by mean ± s.e.m. and were processed using GraphPad Software version 9.5.1. Significant differences between the two groups were tested by using two-tailed unpaired Student t -tests for unequal variances for parasitemia data and one-way ANOVA, followed by Tukey’s post hoc for analysis to evaluate splenomegaly. Statistical differences with P < 0.05 were considered statistically significant at 95% confidence interval (NS, not significant, * P < 0.05, **P < 0.01, ***P < 0.001, and **** P < 0.0001).

Article Snippet: We investigated the effect of co-infection using our bioluminescent B. burgdorferi N40D10/E9 derivative (N40 henceforth) ( ) and B. microti gray strain (ATCC 30221) in both sexes of C3H/HeJ mice in this study to assess pathogenesis from the acute phase of infection (2 weeks) to long-term infection (16 weeks).

Techniques: Infection, Staining, Giemsa Stain, Injection, Software, Two Tailed Test

Journal: Microbiology Spectrum

Article Title: Long-term survival of Babesia microti and Borrelia burgdorferi in C3H/HeJ mice and their effect on Lyme arthritis and babesiosis manifestations

doi: 10.1128/spectrum.00252-25

Figure Lengend Snippet: Babesiosis-associated splenomegaly and colonization by B. burgdorferi detected by live imaging at different stages of infection in C3H/HeJ female mice. ( A ) C3H/HeJ female mice were euthanized by CO 2 asphyxiation at 2, 4, or 16 weeks of infection. Spleens were aseptically harvested and weighed for the determination of splenomegaly. The data represented by mean ± s.e.m. of spleen weights were processed using GraphPad Software version 9.5.1. Significant differences between the two groups were tested by using one-way ANOVA, followed by Tukey’s post hoc test. Statistical differences with P < 0.05 were considered significant at 95% CI (NS, not significant, * P < 0.05, **P < 0.01, ***P < 0.001, and **** P < 0.0001). ( B ) To determine the effect of the Bm infection on N40 colonization, live imaging of C3H/HeJ female mice groups infected with N40 and/or B. microti was determined using IVIS-200 (PerkinElmer) after intraperitoneal (ip) injection of 200 µL of 30 mg/mL D-luciferin at 2, 4, 8, or 16 weeks pi. Based on the net radiance photon measurement, one mouse was selected from each group to represent the average bioluminescence.

Article Snippet: We investigated the effect of co-infection using our bioluminescent B. burgdorferi N40D10/E9 derivative (N40 henceforth) ( ) and B. microti gray strain (ATCC 30221) in both sexes of C3H/HeJ mice in this study to assess pathogenesis from the acute phase of infection (2 weeks) to long-term infection (16 weeks).

Techniques: Imaging, Infection, Software, Injection

Journal: Microbiology Spectrum

Article Title: Long-term survival of Babesia microti and Borrelia burgdorferi in C3H/HeJ mice and their effect on Lyme arthritis and babesiosis manifestations

doi: 10.1128/spectrum.00252-25

Figure Lengend Snippet: Effect of B. microti co-infection on B. burgdorferi N40 colonization levels in female C3H/HeJ mice. ( A ) Live imaging of C3H/HeJ female mice infected with B. burgdorferi N40 and/or B. microti was conducted to detect bioluminescence. Quantification of radiance associated with stably bioluminescent N40 colonization is presented by measuring net radiance (photons/s/cm²/sr) in five mice from each group obtained after deducting values from naïve mice. ( B ) Burden of B. burgdorferi was determined in joints of infected mice by employing duplex qPCR using recA gene of spirochetes and nidogen gene of mice for quantification using specific molecular beacon probes for each gene. In both panels A and B , data were averaged, and standard errors determined the range of radiance obtained at different time points. Significant differences between the two groups were tested by using two-tailed unpaired Student t -tests for unequal variances. Statistical differences were considered statistically significant at 95% CI and are marked by asterisks (NS, not significant, * P < 0.05).

Article Snippet: We investigated the effect of co-infection using our bioluminescent B. burgdorferi N40D10/E9 derivative (N40 henceforth) ( ) and B. microti gray strain (ATCC 30221) in both sexes of C3H/HeJ mice in this study to assess pathogenesis from the acute phase of infection (2 weeks) to long-term infection (16 weeks).

Techniques: Infection, Imaging, Stable Transfection, Two Tailed Test

Journal: Microbiology Spectrum

Article Title: Long-term survival of Babesia microti and Borrelia burgdorferi in C3H/HeJ mice and their effect on Lyme arthritis and babesiosis manifestations

doi: 10.1128/spectrum.00252-25

Figure Lengend Snippet: B. microti infection disrupts BBB integrity and B. burgdorferi colonization in dura mater persists irrespective of co-infection with B. microti . ( A ) To evaluate the integrity of the BBB, penetration of Evans blue dye was evaluated at 2 weeks pi. The BBB disruption is indicated by blue color remaining in the brain even after perfusion with PBS. The brains were then immersed in formamide solution for 48 hours at 37°C to release Evans blue dye, which was quantified in 96-well plates by optical density measurement at 620 nm with a spectrophotometer. A standard curve for Evans Blue with known values was determined to calculate the weight of dye (mg)/formamide (mL). The graph bars at the right side of panel A represent mean ± SD of the dye (mg/mL) released in the formamide solution. Significant differences between the two groups were determined by one-way ANOVA, followed by Tukey’s post hoc test. Statistical differences with P < 0.05 were considered statistically significant at 95% CI (NS, not significant, **** P < 0.0001). ( B ) At 2 weeks post-infection, bioluminescent images of brains from C3H/HeJ female mice infected with N40 alone or together with B. microti were determined using IVIS-200. Mice were anesthetized with isoflurane and intracardially injected with 200 µL 30 mg/mL D-luciferin substrate. After 5 minutes, the animals were euthanized, and skulls opened for acquisition of images for bioluminescence detection in dura mater and brain.

Article Snippet: We investigated the effect of co-infection using our bioluminescent B. burgdorferi N40D10/E9 derivative (N40 henceforth) ( ) and B. microti gray strain (ATCC 30221) in both sexes of C3H/HeJ mice in this study to assess pathogenesis from the acute phase of infection (2 weeks) to long-term infection (16 weeks).

Techniques: Infection, Disruption, Spectrophotometry, Injection

Journal: Microbiology Spectrum

Article Title: Long-term survival of Babesia microti and Borrelia burgdorferi in C3H/HeJ mice and their effect on Lyme arthritis and babesiosis manifestations

doi: 10.1128/spectrum.00252-25

Figure Lengend Snippet: B. microti co-infection enhances inflammatory Lyme arthritis at the early stages of infection . Joints from Naïve or C3H/HeJ female mice infected with B. microti , N40 alone or together with B. microti were harvested at 4 and 16 weeks of infection and prepared for histopathological analysis. Joints were first fixed with formalin, processed using the 10% EDTA-decalcification protocol, and 5-μm-thick sections were cut by a microtome and then mounted on slides for hematoxylin and eosin (H&E) staining. The joints from co-infected mice had higher leukocyte infiltration (indicated by red arrows) compared to N40 singly infected mice, which was more apparent at 4 weeks pi; however, overall histopathology scoring rates were comparable. Inflammation almost completely resolved in all N40-infected and co-infected mice at 16 weeks pi .

Article Snippet: We investigated the effect of co-infection using our bioluminescent B. burgdorferi N40D10/E9 derivative (N40 henceforth) ( ) and B. microti gray strain (ATCC 30221) in both sexes of C3H/HeJ mice in this study to assess pathogenesis from the acute phase of infection (2 weeks) to long-term infection (16 weeks).

Techniques: Infection, Staining, Histopathology

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: Detection of Babesia microti infection using Giemsa-stained thin blood smears of BALB/C mice during a 9-month study.

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Infection

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: The infection rate of mice inoculated with blood containing different densities of B. microti. The infection rate of mice in different groups was calculated based on microscopy.

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Infection, Microscopy

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: The antibody levels in mice inoculated with blood containing different densities of Babesia microti. The levels of specific antibodies against B. microti produced in mice at different time points in different groups were detected by enzyme-linked immunosorbent assay (ELISA).

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Produced, Enzyme-linked Immunosorbent Assay

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: PCR detection of Babesia microti infection in BALB/C mice during a 9-month study.

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Infection

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: The nested PCR detection limit of Babesia microti. (A) Nested PCR analysis of 11 B. microti DNA samples with different concentrations. The DNA concentration of 3 fg/μL (sample No. 8) was found to be the detection limit of the nested PCR. (B) Nested PCR analysis of the DNA of 11 blood samples with different densities of B. microti . The blood with a B. microti density of 5.48 parasites/μL (sample No. 9) was the detection limit of the nested PCR.

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Nested PCR, Concentration Assay

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: Transmission risk assessment of transfusion blood containing an extremely low density of Babesia microti in mouse models. (A) Nested PCR detection of the infection status of the BALB/c mice inoculated with whole blood containing B. microti at a density of 1.08 parasites/µl. One out of three mice was infected. (B) The changes over 28 days in anti- B. microti antibody levels in the three mice inoculated. The infected mice produced higher levels of antibodies on 7, 14 and 28 days post-inoculation (dpi). (C) Infection status of the second-generation mice inoculated with whole blood collected from the first-generation mice inoculated with blood containing anextremely low density of the B. microti (mice in Group 6) for 120 days. (D) The changes over 60 days in anti- B. microti antibody levels in the three mice inoculated. The antibody levels remained low during the 60 days. All these results confirmed that transfusing blood with an extremely low density of B. microti has a high transmission risk.

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Transmission Assay, Nested PCR, Infection, Produced

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: Infection status of the mice inoculated with human blood containing Babesia microti (No. 118).

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Infection, Nested PCR, Microscopy

Journal: Frontiers in Cellular and Infection Microbiology

Article Title: Transmission risk evaluation of transfusion blood containing low-density Babesia microti

doi: 10.3389/fcimb.2024.1334426

Figure Lengend Snippet: Infection status of the mice inoculated with human blood containing Babesia microti (No. 130).

Article Snippet: The standard B. microti Peabodymjr strain (ATCC, PRA-99) was purchased from the American Type Culture Collection (Manassas, VA) and maintained in BALB/c mice by serial passages, according to the methodology described previously ( ).

Techniques: Infection, Nested PCR, Microscopy