Optogenetic Control of Bacterial Cell-Cell Adhesion Dynamics: Unraveling the Influence on Biofilm Architecture and Functionality.

The transition of bacteria from an individualistic to a biofilm lifestyle profoundly alters their biology. During biofilm development, the bacterial cell-cell adhesions are a major determinant of initial microcolonies, which serve as kernels for the subsequent microscopic and mesoscopic structure of the biofilm, and determine the resulting functionality. In this study, the significance of bacterial cell-cell adhesion dynamics on bacterial aggregation and biofilm maturation is elucidated. Using photoswitchable adhesins between bacteria, modifying the dynamics of bacterial cell-cell adhesions with periodic dark-light cycles is systematic. Dynamic cell-cell adhesions with liquid-like behavior improve bacterial aggregation and produce more compact microcolonies than static adhesions with solid-like behavior in both experiments and individual-based simulations. Consequently, dynamic cell-cell adhesions give rise to earlier quorum sensing activation, better intermixing of different bacterial populations, improved biofilm maturation, changes in the growth of cocultures, and higher yields in fermentation. The here presented approach of tuning bacterial cell-cell adhesion dynamics opens the door for regulating the structure and function of biofilms and cocultures with potential biotechnological applications.

An Adenosylcobalamin Specific Whole-Cell Biosensor.

Vitamin B12 (cobalamin) is essential for human health and its deficiency results in anemia and neurological damage. Vitamin B12 exists in different forms with various bioactivity but most sensors are unable to discriminate between them. Here, a whole-cell agglutination assay that is specific for adenosylcobalamin (AboB12), which is one of two bioactive forms, is reported. This biosensor consists of Escherichia coli that express the AdoB12 specific binding domain of CarH at their surface. In the presence of AdoB12, CarH forms tetramers, which leads to specific bacterial cell-cell adhesions and agglutination. These CarH tetramers disassemble upon green light illumination such that reversion of the bacterial aggregation can serve as internal quality control. The agglutination assay has a detection limit of 500 nм AdoB12, works in protein-poor biofluids such as urine, and has high specificity to AdoB12 over other forms of vitamin B12 as also demonstrated with commercially available supplements. This work is a proof of concept for a cheap and easy-to-readout AdoB12 sensor that can be implemented at the point-of-care to monitor high-dose vitamin B12 supplementation.

Carcinoma adenoide quístico parotídeo: soluciones estéticas y funcionales / Adenoid cystic carcinoma of the parotid: an aesthetic and functional solutions

El carcinoma adenoide quístico supone el 10-30% de las neoplasias malignas parotídeas, su tratamiento se basa en una parotidectomía que incluya el tumor con un adecuado margen de seguridad y la radioterapia postoperatoria dado que permite mejorar el control locorregional de la enfermedad. Revisamos un caso que permite exponer el manejo de las secuelas funcionales y estéticas derivadas de su tratamiento. Consideramos adecuada la reconstrucción inmediata del nervio facial cuando se encuentra clínicamente afecto o englobado por el tumor; así como suplir el defecto de volumen posparotidectomía con un colgajo local. Proponemos la anastomosis nerviosa con injerto de nervio sural de las ramas del nervio facial afectas y el relleno del defecto volumen posparotidectomía con un colgajo de fascia temporo-parietal (AU)

Adenoid cystic carcinoma represents 10-30% of all malignant neoplasms in the parotid gland. Treatment is a formal parotidectomy, which includes removing the tumour with an adequate margin and postoperative radiotherapy to improve the locoregional control of the disease. We report a case in order to present the management of the functional and aesthetic consequences obtained from its treatment. When the facial nerve is clinical affected or involved by the tumour, it requires resection and an immediate reconstruction. We suggest the sural nerve graft for the reconstruction of the affected facial branches and the temporo-parietal fascia flap to fill the volume left by the parotidectomy (AU)

Recurrent adenocarcinoma of the sinonasal tract.

BACKGROUND: Adenocarcinomas arising from the nasal cavity and paranasal sinus are malignant tumours that are not of minor salivary gland origin, and they do not demonstrate histopathological features of sinonasal intestinal-type adenocarcinoma. These adenocarcinomas are divided into low- and high-grade subtypes. We herein present a case to highlight the significance of a correct histological diagnosis for treatment and follow-up. CASE REPORT: We report a case of a recurrent low-grade adenocarcinoma arising in the left nasal cavity and extending to the ethmoid, maxillary sinus and orbital floor. No facial deformity or proptosis was present. The diagnosis was made by analysis of a sample taken by biopsy and CT-MRI. We performed a radical maxillectomy and reconstruction with a temporalis muscle flap and a titanium mesh for the orbital floor. DISCUSSION: Low-grade adenocarcinomas of the sinonasal tract are a challenge for the pathologist to differentiate from benign adenomas and high-grade adenocarcinomas, but the distinction is important because the treatment and prognosis differ. Treatment success is determined by complete surgical excision. We also suggest the usefulness of PET to detect recurrence during follow-up.