Robotic kidney transplantation.

Kidney transplantation is the best treatment option for patients with end-stage renal disease owing to improved survival and quality of life compared with dialysis. The surgical approach to kidney transplantation has been somewhat stagnant in the past 50 years, with the open approach being the only available option. In this scenario, evidence of reduced surgery-related morbidity after the introduction of robotics into several surgical fields has induced surgeons to consider robot-assisted kidney transplantation (RAKT) as an alternative approach to these fragile and immunocompromised patients. Since 2014, when the RAKT technique was standardized thanks to the pioneering collaboration between the Vattikuti Urology Institute and the Medanta hospital (Vattikuti Urology Institute-Medanta), several centres worldwide implemented RAKT programmes, providing interesting results regarding the safety and feasibility of this procedure. However, RAKT is still considered an alternative procedure to be offered mainly in the living donor setting, owing to various possible drawbacks such as prolonged rewarming time, demanding learning curve, and difficulties in carrying out this procedure in challenging scenarios (such as patients with obesity, severe atherosclerosis of the iliac vessels, deceased donor setting, or paediatric recipients). Nevertheless, the refinement of robotic platforms through the implementation of novel technologies as well as the encouraging results from multicentre collaborations under the umbrella of the European Association of Urology Robotic Urology Section are currently expanding the boundaries of RAKT, making this surgical procedure a real alternative to the open approach.

Bacillus thuringiensis Cry9Aa Insecticidal Protein Domain I Helices α3 and α4 Are Two Core Regions Involved in Oligomerization and Toxicity.

Bacillus thuringiensis Cry9 proteins show high insecticidal activity against different lepidopteran pests. Cry9 could be a valuable alternative to Cry1 proteins because it showed a synergistic effect with no cross-resistance. However, the pore-formation region of the Cry9 proteins is still unclear. In this study, nine mutations of certain Cry9Aa helices α3 and α4 residues resulted in a complete loss of insecticidal activity against the rice pest Chilo suppressalis; however, the protein stability and receptor binding ability of these mutants were not affected. Among these mutants, Cry9Aa-D121R, Cry9Aa-D125R, Cry9Aa-D163R, Cry9Aa-E165R, and Cry9Aa-D167R are unable to form oligomers in vitro, while the oligomers formed by Cry9Aa-R156D, Cry9Aa-R158D, and Cry9Aa-R160D are unstable and failed to insert into the membrane. These data confirmed that helices α3 and α4 of Cry9Aa are involved in oligomerization, membrane insertion, and toxicity. The knowledge of Cry9 pore-forming action may promote its application as an alternative to Cry1 insecticidal proteins.

JAK/STAT signaling regulated intestinal regeneration defends insect pests against pore-forming toxins produced by Bacillus thuringiensis.

A variety of coordinated host-cell responses are activated as defense mechanisms against pore-forming toxins (PFTs). Bacillus thuringiensis (Bt) is a worldwide used biopesticide whose efficacy and precise application methods limits its use to replace synthetic pesticides in agricultural settings. Here, we analyzed the intestinal defense mechanisms of two lepidopteran insect pests after intoxication with sublethal dose of Bt PFTs to find out potential functional genes. We show that larval intestinal epithelium was initially damaged by the PFTs and that larval survival was observed after intestinal epithelium regeneration. Further analyses showed that the intestinal regeneration caused by Cry9A protein is regulated through c-Jun NH (2) terminal kinase (JNK) and Janus tyrosine kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathways. JAK/STAT signaling regulates intestinal regeneration through proliferation and differentiation of intestinal stem cells to defend three different Bt proteins including Cry9A, Cry1F or Vip3A in both insect pests, Chilo suppressalis and Spodoptera frugiperda. Consequently, a nano-biopesticide was designed to improve pesticidal efficacy based on the combination of Stat double stranded RNA (dsRNA)-nanoparticles and Bt strain. This formulation controlled insect pests with better effect suggesting its potential use to reduce the use of synthetic pesticides in agricultural settings for pest control.

Performance insights into spray-dryer microencapsulated Bacillus thuringiensis cry pesticidal proteins with gum arabic and maltodextrin for effective pest control.

Bacillus thuringiensis (Bt) produces crystals composed mainly of Cry pesticidal proteins with insecticidal activity against pests but are highly susceptible to degradation by abiotic factors. In this sense, encapsulation techniques are designed to improve their performance and lifetime. However, the effects of polymeric matrix encapsulation such as gum arabic and maltodextrin by spray-dryer in the mechanisms of action of Bt kurstaki and Bt aizawai are unknown. We analyzed crystal solubilization, protoxin activation, and receptor binding after microencapsulation and compared them with commercial non-encapsulated products. Microencapsulation did not alter protein crystal solubilization, providing 130 kDa (Cry1 protoxin) and 70 kDa (Cry2 protoxin). Activation with trypsin, chymotrypsin, and larval midgut juice was analyzed, showing that this step is highly efficient, and the protoxins were cleaved producing similar ~ 55 to 65 kDa activated proteins for both formulations. Binding assays with brush border membrane vesicles of Manduca sexta and Spodoptera frugiperda larvae provided a similar binding for both formulations. LC50 bioassays showed no significant differences between treatments but the microencapsulated treatment provided higher mortality against S. frugiperda when subjected to UV radiation. Microencapsulation did not affect the mechanism of action of Cry pesticidal proteins while enhancing protection against UV radiation. These data will contribute to the development of more efficient Bt biopesticide formulations. KEY POINTS: • Microencapsulation did not affect the mechanisms of action of Cry pesticidal proteins produced by Bt. • Microencapsulation provided protection against UV radiation for Bt-based biopesticides. • The study's findings can contribute to the development of more efficient Bt biopesticide formulations.

Apalutamide for prostate cancer: Multicentre and multidisciplinary real-world study of 227 patients.

OBJECTIVE: To evaluate the efficacy and safety of apalutamide prostate cancer compared to the pivotal trials patients and to identify the first subsequent therapy in a real-world setting. METHODS: The study is prospective and observational based on real-world evidence, performed by different medical disciplines and eight academics centres around Barcelona, Spain. It included all patients with metastatic hormone-sensitive prostate cancer (mHSPC) and high-risk non-metastatic castration-resistant prostate cancer (nmCRPC) treated with apalutamide from June 2018 to December 2022. RESULTS: Of 227 patients treated with apalutamide, 10% had ECOG-PS 2, and 41% were diagnosed with new-generation imaging. In the mHSPC group (209 patients), 75 years was the median age, 53% had synchronous metastases, and 22% were M1a. In the nmCRPC (18 patients), 82 years was the median age, and 81% ≤6 months had PSA doubling time. Patients achieved PSA90 in 92% of mHSPC and 50% of nmCRPC and PSA ≤0.2 in 71% of mHSPC and 39% of nmCRPC. Treatment-related adverse events occurred in 40.1% of mHSPC and 44.4% of nmCRPC. After discontinuation of apalutamide due to disease progression, 54.5% in mHSPC and 75% in nmCRPC started chemotherapy, while after discontinuation because of adverse events, 73.3% in mHSPC and 100% in nmCRPC continued with other hormonal-therapies. CONCLUSIONS: The efficacy and safety of apalutamide were similar to that described in the pivotal trials, despite including an older and more comorbid population. Usually, subsequent therapies after apalutamide differed depending on the reason for discontinuation: by disease progression started chemotherapy and by adverse events hormonal sequencing.

Simultaneous Bilateral Video-Endoscopic Inguinal Lymphadenectomy for Penile Carcinoma: Surgical Setting, Feasibility, Safety, and Preliminary Oncological Outcomes.

INTRODUCTION: Inguinal lymph node dissection (ILND) plays an important role for both staging and treatment purposes in patients diagnosed with penile carcinoma (PeCa). Video-endoscopic inguinal lymphadenectomy (VEIL) has been introduced to reduce complications, and in those patients elected for bilateral ILND, a simultaneous bilateral VEIL (sB-VEIL) has also been proposed. This study aimed to investigate the feasibility, safety, and preliminary oncological outcomes of sB-VEIL compared to consecutive bilateral VEIL (cB-VEIL). MATERIAL AND METHODS: Clinical N0-2 patients diagnosed with PeCa and treated with cB-VEIL and sB-VEIL between 2015 and 2023 at our institution were included. Modified ILND was performed in cN0 patients, while cN+ patients underwent a radical approach. Intra- and postoperative complications, operative time, time of drainage maintenance, length of hospital stay and readmission within 90 days, as well as lymph node yield, were compared between the two groups. RESULTS: Overall, 30 patients were submitted to B-VEIL. Of these, 20 and 10 patients underwent cB-VEIL and sB-VEIL, respectively. Overall, 16 (80%) and 7 (70%) patients were submitted to radical ILND due to cN1-2 disease in the cB-VEIL and sB-VEIL groups, respectively. No statistically significant difference emerged in terms of median nodal yield (13.5 vs. 14, p = 0.7) and median positive LNs (p = 0.9). sD-VEIL was associated with a shorter operative time (170 vs. 240 min, p < 0.01). No statistically significant difference emerged in terms of intraoperative estimated blood loss, length of hospital stay, time to drainage tube removal, major complications, and hospital readmission in the cB-VEIL and sB-VEIL groups, respectively (all p > 0.05). CONCLUSIONS: Simultaneous bilateral VEIL is a feasible and safe technique in patients with PeCA, showing similar oncological results and shorter operative time compared to a consecutive bilateral approach. Patients with higher preoperative comorbidity burden or anesthesiological risk are those who may benefit the most from this technique.

Robot-assisted oncologic pelvic surgery with Hugo™ robot-assisted surgery system: A single-center experience.

Objective: To report the outcomes of intra- and extra-peritoneal robot-assisted radical prostatectomy (RARP) and robot-assisted radical cystectomy (RARC) with Hugo™ robot-assisted surgery (RAS) system (Medtronic, Minneapolis, MN, USA). Methods: Data of twenty patients who underwent RARP and one RARC at our institution between February 2022 and January 2023 were reported. The primary endpoint of the study was to report the surgical setting of Hugo™ RAS system to perform RARP and RARC. The secondary endpoint was to assess the feasibility of RARP and RARC with this novel robotic platform and report the outcomes. Results: Seventeen patients underwent RARP with a transperitoneal approach, and three with an extraperitoneal approach; and one patient underwent RARC with intracorporeal ileal conduit. No intraoperative complications occurred. Median docking and console time were 12 (interquartile range [IQR] 7-16) min and 185 (IQR 177-192) min for transperitoneal RARP, 15 (IQR 12-17) min and 170 (IQR 162-185) min for extraperitoneal RARP. No intraoperative complications occurred. One patient submitted to extraperitoneal RARP had a urinary tract infection in the postoperative period that required an antibiotic treatment (Clavien-Dindo Grade 2). In case of transperitoneal RARP, two minor complications occurred (one pelvic hematoma and one urinary tract infection; both Clavien-Dindo Grade 2). Conclusion: Hugo™ RAS system is a novel promising robotic platform that allows to perform major oncological pelvic surgery. We showed the feasibility of RARP both intra- and extra-peritoneally and RARC with intracorporeal ileal conduit with this novel platform.

Identification of Cry toxin receptor genes homologs in a de novo transcriptome of Premnotrypes vorax (Coleoptera: Curculionidae).

The white potato worm Premnotrypes vorax (Hustache) (Coleoptera: Curculionidae) is one of the most destructive insect pests of potato crops in South America. Like many coleopteran insects, P. vorax shows low susceptibility to Cry insecticidal proteins produced by the bacterium Bacillus thuringiensis (Bt). However, the presence of Cry toxin receptors in the midgut of this this insect has never been studied. The main Cry-binding proteins described in other insect species are cadherin (CAD), aminopeptidase N (APN), alkaline phosphatase (ALP) and ATP-binding cassette (ABC) transporters. In this study, we analyzed and validated a de novo assembled transcriptome of Illumina sequencing data to identify and to characterize homologs of Cry toxin receptors. We identified the protein sequences in P. vorax that show high identity with their orthologous sequences of the Cry toxin binding proteins in other coleopteran larvae such as APN, ALP, CAD and ABC transporter. This study provides preliminary identification of putative receptor genes of Cry proteins that would be useful for future studies involving biocontrol of this important potato crop pest.

Helicoverpa armigera GATAe transcriptional factor regulates the expression of Bacillus thuringiensis Cry1Ac receptor gene ABCC2 by its interplay with additional transcription factors.

Helicoverpa armigera is a worldwide pest that has been efficiently controlled by transgenic plants expressing Bt Cry toxins. To exert toxicity, Cry toxins bind to different receptors located in larval midgut cells. Previously, we reported that GATA transcription factor GATAe activates the expression of multiple H. armigera Cry1Ac receptors in different insect cell lines. Here, the mechanism involved in GATAe regulation of HaABCC2 gene expression, a key receptor of Cry1Ac, was analyzed. HaGATAe gene silencing by RNAi in H. armigera larvae confirmed the activation role of HaGATAe on the expression of HaABCC2 in the midgut. The contribution of all potential GATAe-binding sites was analyzed by site-directed mutagenesis using Hi5 cells expressing a reporter gene under regulation of different modified HaABCC2 promoters. DNA pull-down assays revealed that GATAe bound to different predicted GATA-binding sites and mutations of the different GATAe-binding sites identified two binding sites responsible for the promoter activity. The binding site B9, which is located near the transcription initiator site, has a major contribution on HaABCC2 expression. Also, DNA pull-down assays revealed that all other members of GATA TF family in H. armigera, besides GATAe, HaGATAa, HaGATAb, HaGATAc and HaGATAd also bound to the HaABCC2 promoter and decreased the GATAe dependent promoter activity. Finally, the potential participation in the regulation of HaABCC2 promoter of several TFs other than GATA TFs expressed in the midgut cells was analyzed. HaHR3 inhibited the GATAe dependent activity of the HaABCC2 promoter, while two other midgut-related TFs, HaCDX and HaSox21, also bound to the HaABCC2 promoter region and increased the GATAe dependent promoter activity. All these data showed that GATAe induces HaABCC2 expression by binding to HaGATAe binding sites in the promoter region and that additional TFs participate in modulating the HaGATAe-driven expression of HaABCC2.

Aminopeptidase MNP-1 triggers intestine protease production by activating daf-16 nuclear location to degrade pore-forming toxins in Caenorhabditis elegans.

Pore-forming toxins (PFTs) are effective tools for pathogens infection. By disrupting epithelial barriers and killing immune cells, PFTs promotes the colonization and reproduction of pathogenic microorganisms in their host. In turn, the host triggers defense responses, such as endocytosis, exocytosis, or autophagy. Bacillus thuringiensis (Bt) bacteria produce PFT, known as crystal proteins (Cry) which damage the intestinal cells of insects or nematodes, eventually killing them. In insects, aminopeptidase N (APN) has been shown to act as an important receptor for Cry toxins. Here, using the nematode Caenorhabditis elegans as model, an extensive screening of APN gene family was performed to analyze the potential role of these proteins in the mode of action of Cry5Ba against the nematode. We found that one APN, MNP-1, participate in the toxin defense response, since the mnp-1(ok2434) mutant showed a Cry5Ba hypersensitive phenotype. Gene expression analysis in mnp-1(ok2434) mutant revealed the involvement of two protease genes, F19C6.4 and R03G8.6, that participate in Cry5Ba degradation. Finally, analysis of the transduction pathway involved in F19C6.4 and R03G8.6 expression revealed that upon Cry5Ba exposure, the worms up regulated both protease genes through the activation of the FOXO transcription factor DAF-16, which was translocated into the nucleus. The nuclear location of DAF-16 was found to be dependent on mnp-1 under Cry5Ba treatment. Our work provides evidence of new host responses against PFTs produced by an enteric pathogenic bacterium, resulting in activation of host intestinal proteases that degrade the PFT in the intestine.

Can microbial-based insecticides replace chemical pesticides in agricultural production?

Extensive use of chemical insecticides to control insect pests in agriculture has improved yields and production of high-quality food products. However, chemical insecticides have been shown to be harmful also to beneficial insects and many other organisms like vertebrates. Thus, there is a need to replace those chemical insecticides by other control methods in order to protect the environment. Insect pest pathogens, like bacteria, viruses or fungi, are interesting alternatives for production of microbial-based insecticides to replace the use of chemical products in agriculture. Organic farming, which does not use chemical pesticides for pest control, relies on integrated pest management techniques and in the use of microbial-based insecticides for pest control. Microbial-based insecticides require precise formulation and extensive monitoring of insect pests, since they are highly specific for certain insect pests and in general are more effective for larval young instars. Here, we analyse the possibility of using microbial-based insecticides to replace chemical pesticides in agricultural production.

Development of an Online Genome Sequence Comparison Resource for Bacillus cereus sensu lato Strains Using the Efficient Composition Vector Method.

An automated method was developed for differentiating closely related B. cereus sensu lato (s.l.) species, especially biopesticide Bacillus thuringiensis, from other human pathogens, B. anthracis and B. cereus sensu stricto (s.s.). In the current research, four typing methods were initially compared, including multi-locus sequence typing (MLST), single-copy core genes phylogenetic analysis (SCCGPA), dispensable genes content pattern analysis (DGCPA) and composition vector tree (CVTree), to analyze the genomic variability of 23 B. thuringiensis strains from aizawai, kurstaki, israelensis, thuringiensis and morrisoni serovars. The CVTree method was the best option to be used for typing B. thuringiensis strains since it proved to be the fastest method, whilst giving high-resolution data about the strains. In addition, CVTree agrees well with ANI-based method, revealing the relationship between B. thuringiensis and other B. cereus s.l. species. Based on these data, an online genome sequence comparison resource was built for Bacillus strains called the Bacillus Typing Bioinformatics Database to facilitate strain identification and characterization.

Insect chaperones Hsp70 and Hsp90 cooperatively enhance toxicity of Bacillus thuringiensis Cry1A toxins and counteract insect resistance.

Bacillus thuringiensis (Bt) produces different insecticidal proteins effective for pest control. Among them, Cry insecticidal proteins have been used in transgenic plants for the control of insect pests. However, evolution of resistance by insects endangers this technology. Previous work showed that the lepidopteran insect Plutella xylostella PxHsp90 chaperone enhanced the toxicity of Bt Cry1A protoxins by protecting them from degradation by the larval gut proteases and by enhancing binding of the protoxin to its receptors present in larval midgut cells. In this work, we show that PxHsp70 chaperone also protects Cry1Ab protoxin from gut proteases degradation, enhancing Cry1Ab toxicity. We also show that both PxHsp70 and PxHsp90 chaperones act cooperatively, increasing toxicity and the binding of Cry1Ab439D mutant, affected in binding to midgut receptors, to cadherin receptor. Also, insect chaperones recovered toxicity of Cry1Ac protein to a Cry1Ac-highly resistant P. xylostella population, NO-QAGE, that has a disruptive mutation in an ABCC2 transporter linked to Cry1Ac resistance. These data show that Bt hijacked an important cellular function for enhancing its infection capability, making use of insect cellular chaperones for enhancing Cry toxicity and for lowering the evolution of insect resistance to these toxins.

Sequential Treatment With Bacillus Calmette-Güerin (BCG) and Mitomycin C Administered With Electromotive Drug Administration (EMDA) in Patients With High-Risk Nonmuscle Invasive Bladder Cancer After BCG Failure.

BACKGROUND: Nowadays, there is no standard non-surgical treatment for patients with nonmuscle invasive bladder cancer (NMIBC) in whom Bacillus Calmette-Güerin (BCG) therapy has failed. OBJECTIVES: To assess the clinical and oncological outcomes of sequential treatment with Bacillus Calmette-Guerin (BCG) and Mitomycin C (MMC) administered with Electromotive Drug Administration (EMDA) in patients with high-risk NMIBC who fail BCG immunotherapy. MATERIAL AND METHODS: We retrospectively studied patients with NMIBC who failed BCG and received alternating BCG and Mitomycin C with EMDA between 2010 and 2020. Treatment schedule consisted in an induction therapy with 6 instillations (BCG, BCG, MMC + EMDA, BCG, BCG, MMC + EMDA) and a 1-year maintenance. Complete response (CR) was defined as the absence of high-grade (HG) recurrences during follow-up, and progression was defined as the occurrence of muscle invasive or metastatic disease. CR rate was estimated at 3, 6, 12, and 24 months. Progression rate and toxicity were also assessed. RESULTS: Twenty-two patients were included with a median age of 73 years. Fifty percent of tumors were single, 90% were smaller than 1.5cm, 40% were GII (HG) and 40% were Ta. CR rate was 95.5%, 81% and 70% at 3 and 6 months, 12 months and 24 months, respectively. With a median follow-up of 28.8 months, 6 patients (27%) presented HG recurrence and only 1 patient (4.5%) progressed and ended in cystectomy. This patient died due to metastatic disease. Treatment was well tolerated and 22% of the patients presented adverse effects, being dysuria the most frequent one. CONCLUSION: Sequential treatment with BCG and Mitomycin C with EMDA achieved good responses and low toxicity in selected patients who did not respond to BCG. Only 1 patient ended in cystectomy and died due to metastatic disease, therefore, cystectomy was avoided in most cases.

Energy source comparison in en-bloc resection of bladder tumors: subanalysis of a single-center prospective randomized study.

PURPOSE: Different energy sources are employed to perform en-bloc transurethral resection of bladder tumor (ERBT). No study compared different energy sources in ERBT. The aim is to compare the different ERBT sources in terms of pathological, surgical and postoperative outcomes. METHODS: This is a sub-analysis of a prospective randomized trial enrolling patients submitted to ERBT vs conventional TURBT from 03/2018 to 06/2021 (NCT04712201). 180 patients enrolled in ERBT group were randomized 1:1:1 to receive monopolar (m-ERBT), bipolar (b-ERBT) or thulium laser (l-ERBT). Endpoints were the comparison between energies in term of pathological analysis, intra, and post-operative outcomes. RESULTS: 49 (35%) m-ERBT, 45 (32.1%) b-ERBT, and 46 (32.9%) l-ERBT were included in final analysis. The rate of detrusor muscle (DM) presence was comparable between the energies used (p = 0.796) or the location of the lesion (p = 0.662). Five (10.2%), 10 (22.2%) and 0 cases of obturator nerve reflex (ONR) were recorded in m-ERBT, b-ERBT and I-ERBT groups, respectively (p = 0.001). Conversion to conventional TURBT was higher for lesions located in the anterior wall/dome/neck (p < 0.001), irrespective from the energy used. The presence of artifact in the pathological specimen was higher for lesions at the posterior wall (p = 0.03) and trigone (p = 0.03). CONCLUSIONS: In our study, no difference in staging feasibility among energies was found. Laser energy might be beneficial in lateral wall lesions to avoid ONR. Since there is an increased risk of ERBT conversion to conventional TURBT for lesions of the anterior wall, electrocautery might be preferred over laser to avoid waste of material.

A major conformational change of N-terminal helices of Bacillus thuringiensis Cry1Ab insecticidal protein is necessary for membrane insertion and toxicity.

Pore forming toxins rely on oligomerization for membrane insertion to kill their targets. Bacillus thuringiensis produces insecticidal Cry-proteins composed of three domains that form pores that kill the insect larvae. Domain I is involved in oligomerization and membrane insertion, whereas Domains II and III participate in receptor binding and specificity. However, the structural changes involved in membrane insertion of these proteins remain unsolved. The most widely accepted model for membrane insertion, the 'umbrella model', proposed that the α-4/α-5 hairpin of Domain I swings away and is inserted into the membrane. To determine the topology of Cry1Ab in the membrane, disulfide bonds linking α-helices of Domain I were introduced to restrict their movement. Disulfide bonds between helices α-2/α-3 or α-3/α-4 lost oligomerization and toxicity, indicating that movement of these helices is needed for insecticidal activity. By contrast, disulfide bonds linking helices α-5/α-6 did not affect toxicity, which contradicts the 'umbrella model'. Additionally, Föster resonance energy transfer closest approach analyses measuring distances of different points in the toxin to the membrane plane and collisional quenching assays analysing the protection of specific fluorescent-labeled residues to the soluble potassium iodide quencher in the membrane inserted state were performed. Overall, the data show that Domain I from Cry1Ab may undergo a major conformational change during its membrane insertion, where the N-terminal region (helices α-1 to α-4) participates in oligomerization and toxicity, probably forming an extended helix. These data break a paradigm, showing a new 'folding white-cane model', which better explains the structural changes of Cry toxins during insertion into the membrane.

Structural changes upon membrane insertion of the insecticidal pore-forming toxins produced by Bacillus thuringiensis.

Different Bacillus thuringiensis (Bt) strains produce a broad variety of pore-forming toxins (PFTs) that show toxicity against insects and other invertebrates. Some of these insecticidal PFT proteins have been used successfully worldwide to control diverse insect crop pests. There are several studies focused on describing the mechanism of action of these toxins that have helped to improve their performance and to cope with the resistance evolved by different insects against some of these proteins. However, crucial information that is still missing is the structure of pores formed by some of these PFTs, such as the three-domain crystal (Cry) proteins, which are the most commercially used Bt toxins in the biological control of insect pests. In recent years, progress has been made on the identification of the structural changes that certain Bt insecticidal PFT proteins undergo upon membrane insertion. In this review, we describe the models that have been proposed for the membrane insertion of Cry toxins. We also review the recently published structures of the vegetative insecticidal proteins (Vips; e.g. Vip3) and the insecticidal toxin complex (Tc) in the membrane-inserted state. Although different Bt PFTs show different primary sequences, there are some similarities in the three-dimensional structures of Vips and Cry proteins. In addition, all PFTs described here must undergo major structural rearrangements to pass from a soluble form to a membrane-inserted state. It is proposed that, despite their structural differences, all PFTs undergo major structural rearrangements producing an extended α-helix, which plays a fundamental role in perforating their target membrane, resulting in the formation of the membrane pore required for their insecticidal activity.

A single transcription factor facilitates an insect host combating Bacillus thuringiensis infection while maintaining fitness.

Maintaining fitness during pathogen infection is vital for host survival as an excessive response can be as detrimental as the infection itself. Fitness costs are frequently associated with insect hosts countering the toxic effect of the entomopathogenic bacterium Bacillus thuringiensis (Bt), which delay the evolution of resistance to this pathogen. The insect pest Plutella xylostella has evolved a mechanism to resist Bt toxins without incurring significant fitness costs. Here, we reveal that non-phosphorylated and phosphorylated forms of a MAPK-modulated transcription factor fushi tarazu factor 1 (FTZ-F1) can respectively orchestrate down-regulation of Bt Cry1Ac toxin receptors and up-regulation of non-receptor paralogs via two distinct binding sites, thereby presenting Bt toxin resistance without growth penalty. Our findings reveal how host organisms can co-opt a master molecular switch to overcome pathogen invasion with low cost, and contribute to understanding the underlying mechanism of growth-defense tradeoffs during host-pathogen interactions in P. xylostella.