A novel approach to isolation and screening of calcifying bacteria for biotechnological applications

Bacterial calcium-carbonate precipitation (BCP) has been studied for multiple applications such as remediation, consolidation, and cementation. Isolation and screening of strong calcifying bacteria is the main task of BCP-technique. In this paper, we studied CaCO3 precipitation by different bacteria isolated from a rhizospheric soil in both solid and liquid media. It has been found, through culture-depending studies, that bacteria belonging to Actinobacteria, Gammaproteobacteria, and Alphaproteobacteria are the dominant bacteria involved in CaCO3 precipitation in this environment. Pure and mixed cultures of selected strains were applied for sand biocementation experiments. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the biotreated samples revealed the biological nature of the cementation and the effectiveness of the biodeposition treatment by mixed cultures. X-ray diffraction (XRD) analysis confirmed that all the calcifying strains selected for sand biocementation precipitated CaCO3, mostly in the form of calcite. In this study, Biolog® EcoPlate is evaluated as a useful method for a more targeted choice of the sampling site with the purpose of obtaining interesting candidates for BCP applications. Furthermore, ImageJ software was investigated, for the first time to our knowledge, as a potential method to screen high CaCO3 producer strains

Erratic calcareous deposits: Biotic formation insights and biomineralising bacterial strain isolation

The present study investigated the contribution of microbial communities in producing "living stones" and the suitability of these clasts as sources of microorganisms with biomineralisation abilities. The calcareous samples were analysed for their microbial community (16S rRNA gene metabarcoding and culturable approach) and in vitro regeneration tests. Scanning electron microscopy and Energy Dispersive Spectroscopy (SEM-EDX) were applied to investigate microbial aggregation structures and footprints in natural and in vitro samples. The metabarcoding unveiled amplicon sequence variants (ASVs) assigned to lineages with biomineralisation abilities (e.g., Proteobacteria and Actinobacteriota). The culturable approach resulted in nineteen calcifying isolates with diverse morphological, metabolic, and mineral precipitation properties. Based on mineralising properties, Stenotrophomonas maltophilia, Lysinbacillus fusiformis, and Microbacterium ginsengiterrae were identified at the molecular level. In vitro regeneration tests and SEM-EDX analyses confirmed the active role of the endogenous microorganisms in forming these “living stones”. These findings allow us to hypothesise an essential role of microbial precipitation in forming these “living stones”, previously described as of abiotic origin. The current study findings provide a solid scientific foundation for future investigations. The obtained bacterial isolates and their potential applications in bioremediation, construction, and cultural heritage restoration demonstrate the direct applicability of our study in sectors involving biomaterials application. Statement of significance: We studied some "living stones" that can be found worldwide and whose origin is still not completely understood. Geologists have not yet fully explained the origin of these inorganic structures that grow in size over time. The results obtained from our microbiological investigations allowed us to discover that microorganisms play a crucial role in forming these masses. In the investigations of the structures and microbial communities within the stones, we identified specific bacteria that actively contribute to forming minerals and isolated bacteria that can form biominerals. These findings deepen our understanding of natural processes involved in the formation of these structures and show their potential for several applications (e.g., building materials or cultural heritage preservation)

Preliminary indication of the role of AHL-dependent quorum sensing systems in calcium carbonate precipitation in Gram-negative bacteria

Numerous microbial species participate in precipitation of carbonates in various natural environments, including soils, geological formations, freshwater biofilms and oceans. Despite the geochemical interest of such a biomineralization process, its molecular mechanisms and adaptive aspects remain poorly known. Many Gram-negative bacteria use cell-to-cell communication systems relying on N-acylhomoserine lactone (AHLs) signal molecules to express certain phenotypic traits in a density-dependent manner, a phenomenon referred as to quorum-sensing (QS). In this work, bacterial isolates collected from cave and rhizosphere soil were analyzed to study the occurrence of the AHL-mediated QS in bacterial calcium carbonate (CaCO3) precipitation. To test the production of AHLs signal molecules, we cross-streaked Gram-negative calcifying strains, selected among the environmental strains studied, with the AHL-negative mutant Chromobacterium subtsugae strain CV026. Only Burkholderia ambifaria LMG 11351 was able to restore violacein production in CV026 among the tested strains. The constructed AHL-negative mutant of B. ambifaria LMG 11351 could not precipitate CaCO3 on B-4 agar. Scanning Electron Microscopy (SEM) analysis on CaCO3 crystals obtained in vitro shows crystals of different morphologies, calcified biofilms and bacteria in close contact with the precipitated crystals. In the inner layers of the bioliths deposited by B. ambifaria LMG 11351, a stream-like organization of the Burkholderia imprints was not detected by SEM. Our data provide preliminary evidence that the activation of AHL-regulated genes may be a prerequisite for in vitro bacterial carbonatogenesis, in some cases, confirming the specific role of bacteria as CaCO3 precipitating agents. We enhance the understanding of bacterial CaCO3 biomineralization and has potential biotechnology implications for QS-based strategies to enhance or decrease CaCO3 precipitation through specific bacterial processes. The AHL-negative mutant of B. ambifaria LMG 11351 (a well-known plant growth-promoting bacterium) could also be used to study plant-bacteria interactions. The adaptive role of bacterial CaCO3 biomineralization was also discussed

Radial Extracorporeal Shock Wave Therapy Is Effective and Safe in Chronic Distal Biceps Tendinopathy

OBJECTIVE:: To assess the efficacy and safety of radial extracorporeal shock wave therapy (rESWT) for chronic distal biceps tendinopathy (cDBT). DESIGN:: Caseâcontrol study (level of evidence, 3). SETTING:: SUN Orthopaedics and Sports Medicine. PATIENTS:: Patients with a diagnosis of cDBT were recruited between January 2010 and February 2015. INTERVENTIONS:: Patients received a single session of rESWT (2000 shock waves with energy flux density of 0.18 mJ/mm) or other forms of nonoperative therapy. MAIN OUTCOME MEASURES:: Patients completed the visual analog scale (VAS), the modified QuickDASH (MQD) score, and the Roles and Maudsley (RM) score over a 12-month period. RESULTS:: Forty-eight patients completed the final review at 12 months and were included in the study. Subjects ranged in age from 30 to 64 years. Mean pretreatment VAS scores for the rESWT and control groups were 8.3 and 8.5, respectively. Three and 12 months after inclusion in the study, the mean VAS scores for the rESWT and control groups were 3.4 and 5.6 (P < 0.001) and 2.7 and 4.7 (P < 0.001), respectively. Twelve-month follow-up MQD-Sports and MQD-Work scores for the rESWT and control groups were 3.7 and 1.7 (P < 0.001) and 3.8 and 1.8 (P < 0.001), respectively. Differences in mean RM scores were statistically significant between groups at 3 months after the treatment. There were no significant complications. CONCLUSIONS:: Overall, rESWT is an effective and safe treatment for cDBT. CLINICAL RELEVANCE:: Radial ESWT as a novel, effective, and safe treatment for cDBT

Repeatability of Corticospinal and Spinal Measures during Lengthening and Shortening Contractions in the Human Tibialis Anterior Muscle

Elements of the human central nervous system (CNS) constantly oscillate. In addition, there are also methodological factors and changes in muscle mechanics during dynamic muscle contractions that threaten the stability and consistency of transcranial magnetic stimulation (TMS) and perpherial nerve stimulation (PNS) measures

Behavioral and psychological effects of coronavirus disease-19 quarantine in patients with dementia

Background: In March 2020, the World Health Organization declared a global pandemic due to the novel coronavirus SARS-CoV-2 and several governments planned a national quarantine in order to control the virus spread. Acute psychological effects of quarantine in frail elderly subjects with special needs, such as patients with dementia, have been poorly investigated. The aim of this study was to assess modifications of neuropsychiatric symptoms during quarantine in patients with dementia and their caregivers. Methods: This is a sub-study of a multicenter nation-wide survey. A structured telephone interview was delivered to family caregivers of patients with diagnosis of Alzheimer disease (AD), dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), and vascular dementia (VD), followed regularly at 87 Italian memory clinics. Variations in behavioral and psychological symptoms (BPSD) were collected after 1 month since quarantine declaration and associations with disease type, severity, gender, and caregiver\u2019s stress burden were analyzed. Results: A total of 4,913 caregivers participated in the survey. Increased BPSD was reported in 59.6% of patients as worsening of preexisting symptoms (51.9%) or as new onset (26%), and requested drug modifications in 27.6% of these cases. Irritability, apathy, agitation, and anxiety were the most frequently reported worsening symptoms and sleep disorder and irritability the most frequent new symptoms. Profile of BPSD varied according to dementia type, disease severity, and patients\u2019 gender. Anxiety and depression were associated with a diagnosis of AD (OR 1.35, CI: 1.12\u20131.62), mild to moderate disease severity and female gender. DLB was significantly associated with a higher risk of worsening hallucinations (OR 5.29, CI 3.66\u20137.64) and sleep disorder (OR 1.69, CI 1.25\u20132.29), FTD with wandering (OR 1.62, CI 1.12\u20132.35), and change of appetite (OR 1.52, CI 1.03\u20132.25). Stress-related symptoms were experienced by two-thirds of caregivers and were associated with increased patients\u2019 neuropsychiatric burden (p&lt;0.0001). Conclusion: Quarantine induces a rapid increase of BPSD in approximately 60% of patients and stress-related symptoms in two-thirds of caregivers. Health services need to plan a post-pandemic strategy in order to address these emerging needs

"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool

Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 \ub1 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys