Killing in the name of: T6SS structure and effector diversity.

The life of bacteria is challenging, to endure bacteria employ a range of mechanisms to optimize their environment, including deploying the type VI secretion system (T6SS). Acting as a bacterial crossbow, this system delivers effectors responsible for subverting host cells, killing competitors and facilitating general secretion to access common goods. Due to its importance, this lethal machine has been evolutionarily maintained, disseminated and specialized to fulfil these vital functions. In fact, T6SS structural clusters are present in over 25 % of Gram-negative bacteria, varying in number from one to six different genetic clusters per organism. Since its discovery in 2006, research on the T6SS has rapidly progressed, yielding remarkable breakthroughs. The identification and characterization of novel components of the T6SS, combined with biochemical and structural studies, have revealed fascinating mechanisms governing its assembly, loading, firing and disassembly processes. Recent findings have also demonstrated the efficacy of this system against fungal and Gram-positive cells, expanding its scope. Ongoing research continues to uncover an extensive and expanding repertoire of T6SS effectors, the genuine mediators of T6SS function. These studies are shedding light on new aspects of the biology of prokaryotic and eukaryotic organisms. This review provides a comprehensive overview of the T6SS, highlighting recent discoveries of its structure and the diversity of its effectors. Additionally, it injects a personal perspective on avenues for future research, aiming to deepen our understanding of this combative system.

Prevention of Equinus Deformity after External Fixation for Open Tibia Fractures: A Comparison between Plaster of Paris Backslab and Passive Ankle Physiotherapy.

Background: Ankle equinus deformity is a common complication of prolonged external fixator use in tibia fractures with an incidence of 15%-16%. It affects gait and may lead to foot, leg, and back problems. Treatment of equinus deformity increases the cost of treatment of open tibia fractures and increases the time spent off work. Several preventive modalities have been suggested in literature with variable success, but no standard protocol exists. Objectives: The aim of this study was to determine the most appropriate method of preventing equinus deformity of the ankle joint during the management of open tibia fractures with unilateral uniplanar external fixators by comparing plaster of paris (POP) backslab application with passive ankle physiotherapy using strips of car tyre inner tubing. Materials and Methods: The study was a prospective randomised study involving patients with open tibia fractures who were managed with external fixators at the Korle Bu Teaching Hospital between April 2020 and February 2021. Patients were randomised into two groups; one group had below knee POP backslab and the other group did passive ankle physiotherapy using a strip of car tyre inner tubing. The passive ankle range of motion was measured at the beginning and after 6 weeks using a goniometer. Results: Fifty-six participants were recruited with 29 in the POP backslab group and 27 in the ankle physiotherapy group. The median age was 35.0 years. Male-to-female ratio was 4.6:1. Motor vehicle crash contributed to over 90% with 42.9% being motorbike riders. Initial and final mean ankle measurements for the POP backslab group were 6.79° and 10.14° for dorsiflexion and 29.93° and 34.52° for plantarflexion, respectively. The ankle physiotherapy group had initial and final dorsiflexion of 7.19° and 12.85° and plantarflexion of 30.44° and 34.52°, respectively. The ankle physiotherapy group had a better range of motion (47.37°) than the POP group (40.66°) with a P value of 0.008. One participant (3.7%) from the ankle physiotherapy group had equinus deformity compared with seven (24%) from the POP backslab group, a difference which gives a P value of 0.029. Conclusions: Passive ankle physiotherapy with car tyre inner tube is a better and cheaper modality of preventing ankle equinus deformity and maintaining ankle range of motion.