Substrate and nutrient manipulation during continuous cultivation of extremophilic algae, Galdieria spp. RTK 37.1, substantially impacts biomass productivity and composition.

The extremophilic nature and metabolic flexibility of Galdieria spp. highlights their potential for biotechnological application. However, limited research into continuous cultivation of Galdieria spp. has slowed progress towards the commercialization of these algae. The objective of this research was to investigate biomass productivity and growth yields during continuous photoautotrophic, mixotrophic and heterotrophic cultivation of Galdieria sp. RTK371; a strain recently isolated from within the Taupo Volcanic Zone in Aotearoa-New Zealand. Results indicate Galdieria sp. RTK371 grows optimally at pH 2.5 under warm white LED illumination. Photosynthetic O2 production was dependent on lighting intensity with a maximal value of (133.5 ± 12.1 nmol O2 mgbiomass -1 h-1) achieved under 100 µmol m-2 s-1 illumination. O2 production rates slowed significantly to 42 ± 1 and <0.01 nmol O2 mgbiomass -1 h-1 during mixotrophic and heterotrophic growth regimes respectively. Stable, long-term chemostat growth of Galdieria sp. RTK371 was achieved during photoautotrophic, mixotrophic and heterotrophic growth regimes. During periods of ammonium limitation, Galdieria sp. RTK371 increased its intracellular carbohydrate content (up to 37% w/w). In contrast, biomass grown in ammonium excess was composed of up to 65% protein (w/w). Results from this study demonstrate that the growth of Galdieria sp. RTK371 can be manipulated during continuous cultivation to obtain desired biomass and product yields over long cultivation periods.

Load-velocity Relationship of the Bench Press Exercise is not Affected by Breast Cancer Surgery and Adjuvant Therapy.

We examined the effect of breast cancer surgery and adjuvant therapy on the relationship between bar velocity and relative intensity (load-velocity [L-V] relationship) of the bench press (BP) exercise. Twenty-two breast cancer survivors (age: 48.0±8.2 yr., relative strength: 0.40±0.08) completed a loading test up to the one-repetition maximum (1RM) in the BP using a lightweight carbon bar. General and individual relationships between relative intensity (%1RM) and mean propulsive velocity (MPV) were studied. Furthermore, the mean test velocity (MPVTest) and velocity attained to the 1RM (MPV1RM) were analyzed. These procedures and analyses were also conducted in 22 healthy women (age: 47.8±7.1 yr., relative strength: 0.41±0.09) to examine the differences in velocity parameters derived from these L-V relationships. Polynomial regressions showed very close relationships (R2≥0.965) and reduced estimation errors (≤4.9% 1RM) for both groups. Between-group differences in MPV attained to each %1RM were small (≤0.01 m·s-1) and not significant (p≥0.685). Similarly, the MPVTest (0.59±0.06 m·s-1) and MPV1RM (0.17±0.03 m·s-1) were identical for breast cancer survivors and healthy women. These results suggest that practitioners could use the same velocity parameters derived from the BP L-V relationship to prescribe this exercise in middle-aged women, regardless of whether they have suffered from breast cancer.

First-trimester plasma extracellular heat shock proteins levels and risk of preeclampsia.

Preeclampsia (PE) occurs annually in 8% of pregnancies. Patients without risk factors represent 10% of these. There are currently no first-trimester biochemical markers that accurately predict PE. An increase in serum 60- and 70-KDa extracellular heat shock proteins (eHsp) has been shown in patients who developed PE at 34 weeks. We sought to determine whether there is a relationship between first-trimester eHsp and the development of PE. This was a prospective cohort study performed at a third level hospital in Mexico City from 2019 to 2020. eHsp levels were measured during the first-trimester ultrasound in singleton pregnancies with no comorbidities. First-trimester eHsp levels and biochemical parameters of organ dysfunction were compared between patients who developed preeclampsia and those who did not. All statistical analyses and model of correlation (r) between eHsp and clinical parameter were performed using bootstrapping R-software. p-values <0.05 were considered significant. The final analysis included 41 patients. PE occurred in 11 cases. eHsp-60 and eHsp-70 were significantly higher at 12 weeks in patients who developed PE (p = 0.001), while eHsp-27 was significantly lower (p = 0.004). Significant differences in first-trimester eHsp concentration suggest that these are possible early biomarkers useful for the prediction of PE.

A multifaceted small RNA modulates gene expression upon glucose limitation in Staphylococcus aureus.

Pathogenic bacteria must rapidly adapt to ever-changing environmental signals resulting in metabolism remodeling. The carbon catabolite repression, mediated by the catabolite control protein A (CcpA), is used to express genes involved in utilization and metabolism of the preferred carbon source. Here, we have identified RsaI as a CcpA-repressed small non-coding RNA that is inhibited by high glucose concentrations. When glucose is consumed, RsaI represses translation initiation of mRNAs encoding a permease of glucose uptake and the FN3K enzyme that protects proteins against damage caused by high glucose concentrations. RsaI also binds to the 3' untranslated region of icaR mRNA encoding the transcriptional repressor of exopolysaccharide production and to sRNAs induced by the uptake of glucose-6 phosphate or nitric oxide. Furthermore, RsaI expression is accompanied by a decreased transcription of genes involved in carbon catabolism pathway and an activation of genes involved in energy production, fermentation, and nitric oxide detoxification. This multifaceted RNA can be considered as a metabolic signature when glucose becomes scarce and growth is arrested.

Confirmation of the presence of Rickettsia felis infecting Ornithodoros puertoricensis in Mexico.

Soft ticks are neglected competent vectors of a wide range of pathogenic microorganisms, among which bacteria of the genera Rickettsia and Borrelia stand out. In Mexico, previous studies have shown the presence of a member of the Ornithodoros talaje complex in the Virginia opossum (Didelphis virginiana Didelphimorphia: Didelphidae Kerr) from southeastern Mexico. However, its specific identification has not been achieved. Two D. virginiana were treated in a private clinic during the period of April-May 2022. Tick larvae were manually removed, DNA extraction was performed, and some genes from various bacterial and parasitic pathogens were amplified and sequenced. A total of 96 larvae were recovered, which were morphologically identified as Ornithodoros puertoricensis (Ixodida: Argasidae Fox); the 16 S sequences showed a similarity of 96.79%-99.51% with sequences of O. puertoricensis from Panama and Colombia. The presence of Rickettsia felis (Rickettsiales: Rickettsiaceae Bouyer et al.) was detected in 15 specimens from one host. The soft tick O. puertoricensis is recorded for the first time as an ectoparasite of the Virginia opossum in America and represents the second report for this soft tick in Mexico since 1963. This represents the most northern record of this tick species in its geographic distribution and brings a new soft tick-Rickettsia association.

RNA thermoswitches modulate Staphylococcus aureus adaptation to ambient temperatures.

Thermoregulation of virulence genes in bacterial pathogens is essential for environment-to-host transition. However, the mechanisms governing cold adaptation when outside the host remain poorly understood. Here, we found that the production of cold shock proteins CspB and CspC from Staphylococcus aureus is controlled by two paralogous RNA thermoswitches. Through in silico prediction, enzymatic probing and site-directed mutagenesis, we demonstrated that cspB and cspC 5'UTRs adopt alternative RNA structures that shift from one another upon temperature shifts. The open (O) conformation that facilitates mRNA translation is favoured at ambient temperatures (22°C). Conversely, the alternative locked (L) conformation, where the ribosome binding site (RBS) is sequestered in a double-stranded RNA structure, is folded at host-related temperatures (37°C). These structural rearrangements depend on a long RNA hairpin found in the O conformation that sequesters the anti-RBS sequence. Notably, the remaining S. aureus CSP, CspA, may interact with a UUUGUUU motif located in the loop of this long hairpin and favour the folding of the L conformation. This folding represses CspB and CspC production at 37°C. Simultaneous deletion of the cspB/cspC genes or their RNA thermoswitches significantly decreases S. aureus growth rate at ambient temperatures, highlighting the importance of CspB/CspC thermoregulation when S. aureus transitions from the host to the environment.

Association of Metformin Use During Hospitalization and Mortality in Critically Ill Adults With Type 2 Diabetes Mellitus and Sepsis.

OBJECTIVES: Whether metformin exposure is associated with improved outcomes in patients with type 2 diabetes mellitus and sepsis. DESIGN: Retrospective cohort study. SETTING: Patients admitted to ICUs in 16 hospitals in Pennsylvania from October 2008 to December 2014. PATIENTS: Adult critical ill patients with type 2 diabetes mellitus and sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We conducted a retrospective cohort study to compare 90-day mortality in diabetic patients with sepsis with and without exposure to metformin during hospitalization. Data were obtained from the electronic health record of a large healthcare system in Pennsylvania from October 2008 to December 2014, on patients admitted to the ICU at any of the 16 hospitals within the system. The primary outcome was mortality at 90 days. The absolute and adjusted odds ratio (OR) with 95% CI were calculated in a propensity score-matched cohort. Among 14,847 patients with type 2 diabetes mellitus and sepsis, 682 patients (4.6%) were exposed to metformin during hospitalization and 14,165 (95.4%) were not. Within a total of 2,691 patients subjected to propensity score-matching at a 1:4 ratio, exposure to metformin (n = 599) was associated with decreased 90-day mortality (71/599, 11.9% vs 475/2,092, 22.7%; OR, 0.46; 95% CI, 0.35-0.60), reduced severe acute kidney injury (50% vs 57%; OR, 0.75; 95% CI, 0.62-0.90), less Major Adverse Kidney Events at 1 year (OR, 0.27; 95% CI, 0.22-0.68), and increased renal recovery (95% vs 86%; OR, 6.43; 95% CI, 3.42-12.1). CONCLUSIONS: Metformin exposure during hospitalization is associated with a decrease in 90-day mortality in patients with type 2 diabetes mellitus and sepsis.

Differential evolution in 3'UTRs leads to specific gene expression in Staphylococcus.

The evolution of gene expression regulation has contributed to species differentiation. The 3' untranslated regions (3'UTRs) of mRNAs include regulatory elements that modulate gene expression; however, our knowledge of their implications in the divergence of bacterial species is currently limited. In this study, we performed genome-wide comparative analyses of mRNAs encoding orthologous proteins from the genus Staphylococcus and found that mRNA conservation was lost mostly downstream of the coding sequence (CDS), indicating the presence of high sequence diversity in the 3'UTRs of orthologous genes. Transcriptomic mapping of different staphylococcal species confirmed that 3'UTRs were also variable in length. We constructed chimeric mRNAs carrying the 3'UTR of orthologous genes and demonstrated that 3'UTR sequence variations affect protein production. This suggested that species-specific functional 3'UTRs might be specifically selected during evolution. 3'UTR variations may occur through different processes, including gene rearrangements, local nucleotide changes, and the transposition of insertion sequences. By extending the conservation analyses to specific 3'UTRs, as well as the entire set of Escherichia coli and Bacillus subtilis mRNAs, we showed that 3'UTR variability is widespread in bacteria. In summary, our work unveils an evolutionary bias within 3'UTRs that results in species-specific non-coding sequences that may contribute to bacterial diversity.

Regulation of Heterogenous LexA Expression in Staphylococcus aureus by an Antisense RNA Originating from Transcriptional Read-Through upon Natural Mispairings in the sbrB Intrinsic Terminator.

Bacterial genomes are pervasively transcribed, generating a wide variety of antisense RNAs (asRNAs). Many of them originate from transcriptional read-through events (TREs) during the transcription termination process. Previous transcriptome analyses revealed that the lexA gene from Staphylococcus aureus, which encodes the main SOS response regulator, is affected by the presence of an asRNA. Here, we show that the lexA antisense RNA (lexA-asRNA) is generated by a TRE on the intrinsic terminator (TTsbrB) of the sbrB gene, which is located downstream of lexA, in the opposite strand. Transcriptional read-through occurs by a natural mutation that destabilizes the TTsbrB structure and modifies the efficiency of the intrinsic terminator. Restoring the mispairing mutation in the hairpin of TTsbrB prevented lexA-asRNA transcription. The level of lexA-asRNA directly correlated with cellular stress since the expressions of sbrB and lexA-asRNA depend on the stress transcription factor SigB. Comparative analyses revealed strain-specific nucleotide polymorphisms within TTsbrB, suggesting that this TT could be prone to accumulating natural mutations. A genome-wide analysis of TREs suggested that mispairings in TT hairpins might provide wider transcriptional connections with downstream genes and, ultimately, transcriptomic variability among S. aureus strains.

One evolutionarily selected amino acid variation is sufficient to provide functional specificity in the cold shock protein paralogs of Staphylococcus aureus.

Bacterial genomes encode several families of protein paralogs. Discrimination between functional divergence and redundancy among paralogs is challenging due to their sequence conservation. Here, we investigated whether the amino acid differences present in the cold shock protein (CSP) paralogs of Staphylococcus aureus were responsible for functional specificity. Since deletion of cspA reduces the synthesis of staphyloxanthin (STX), we used it as an in vivo reporter of CSP functionality. Complementation of a ΔcspA strain with the different S. aureus CSP variants showed that only CspA could specifically restore STX production by controlling the activity of the stress-associated sigma B factor (σB ). To determine the amino acid residues responsible for CspA specificity, we created several chimeric CSPs that interchanged the amino acid differences between CspA and CspC, which shared the highest identity. We demonstrated that CspA Pro58 was responsible for the specific control of σB activity and its associated phenotypes. Interestingly, CspC gained the biological function of CspA when the E58P substitution was introduced. This study highlights how just one evolutionarily selected amino acid change may be sufficient to modify the specific functionality of CSP paralogs.

Activation of AMP-activated protein kinase during sepsis/inflammation improves survival by preserving cellular metabolic fitness.

The purpose was to determine the role of AMPK activation in the renal metabolic response to sepsis, the development of sepsis-induced acute kidney injury (AKI) and on survival. In a prospective experimental study, 167 10- to 12-week-old C57BL/6 mice underwent cecal ligation and puncture (CLP) and human proximal tubule epithelial cells (TEC; HK2) were exposed to inflammatory mix (IM), a combination of lipopolysaccharide (LPS) and high mobility group box 1 (HMGB1). Renal/TEC metabolic fitness was assessed by monitoring the expression of drivers of oxidative phosphorylation (OXPHOS), the rates of utilization of OXPHOS/glycolysis in response to metabolic stress, and mitochondrial function by measuring O2 consumption rates (OCR) and the membrane potential (Δψm ). Sepsis/IM resulted in AKI, increased mortality, and in renal AMPK activation 6-24 hours after CLP/IM. Pharmacologic activation of AMPK with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or metformin during sepsis improved the survival, while AMPK inhibition with Compound C increased mortality, impaired mitochondrial respiration, decreased OCR, and disrupted TEC metabolic fitness. AMPK-driven protection was associated with increased Sirt 3 expression and restoration of metabolic fitness. Renal AMPK activation in response to sepsis/IM is an adaptive mechanism that protects TEC, organs, and the host by preserving mitochondrial function and metabolic fitness likely through Sirt3 signaling.

Dual Neurostimulant Therapy May Optimize Acute Neurorecovery for Severe Traumatic Brain Injuries.

BACKGROUND: Neurostimulants (NS) can be used to treat patients with a traumatic brain injury (TBI) with altered levels of consciousness. We sought to determine if amantadine alone (monotherapy) versus amantadine + methylphenidate (dual therapy) would correlate with better neurorecovery (NR) among acutely hospitalized patients with a severe TBI. METHODS: We performed a retrospective review of adult patients admitted to our level I trauma center from 2016-2019 with a severe TBI. NR was calculated by dividing the difference between admission and discharge Glasgow Coma Scale (GCS) scores by 12. Resulting ratios were used to divide the cohort into two groups: excellent NR (1) and non-excellent NR (<1). RESULTS: A total of 76 patients comprised the cohort; 19.7% (n = 15) had excellent NR. The excellent NR group had a larger proportion of patients receiving dual therapy compared to the non-excellent group (86.7% versus 59%, P = 0.04). In monotherapy (n = 27), amantadine was initiated 13 (8-20) d following injury and treatment lasted 7 (2-16) d. In dual therapy (n = 49), amantadine was initiated 12 (6-19) d following injury and continued for 9 (4-25.5) d. Methylphenidate was initiated 15 (7-20.5) d following injury and continued for 5 (2-13.5) d. After adjusting for confounders, dual versus monotherapy predicted excellent NR (OR 5.4, 95% CI 1.2 - 38.9, P = 0.03). CONCLUSIONS: During the acute hospitalization for a severe TBI, dual NS therapy compared to monotherapy is associated with an increased likelihood of excellent NR. Larger prospective trials are warranted to validate these findings.

The regulon of the RNA chaperone CspA and its auto-regulation in Staphylococcus aureus.

RNA-binding proteins (RBPs) are essential to fine-tune gene expression. RBPs containing the cold-shock domain are RNA chaperones that have been extensively studied. However, the RNA targets and specific functions for many of them remain elusive. Here, combining comparative proteomics and RBP-immunoprecipitation-microarray profiling, we have determined the regulon of the RNA chaperone CspA of Staphylococcus aureus. Functional analysis revealed that proteins involved in carbohydrate and ribonucleotide metabolism, stress response and virulence gene expression were affected by cspA deletion. Stress-associated phenotypes such as increased bacterial aggregation and diminished resistance to oxidative-stress stood out. Integration of the proteome and targetome showed that CspA post-transcriptionally modulates both positively and negatively the expression of its targets, denoting additional functions to the previously proposed translation enhancement. One of these repressed targets was its own mRNA, indicating the presence of a negative post-transcriptional feedback loop. CspA bound the 5'UTR of its own mRNA disrupting a hairpin, which was previously described as an RNase III target. Thus, deletion of the cspA 5'UTR abrogated mRNA processing and auto-regulation. We propose that CspA interacts through a U-rich motif, which is located at the RNase III cleavage site, portraying CspA as a putative RNase III-antagonist.

Acute kidney injury from sepsis: current concepts, epidemiology, pathophysiology, prevention and treatment.

Sepsis-associated acute kidney injury (S-AKI) is a frequent complication of the critically ill patient and is associated with unacceptable morbidity and mortality. Prevention of S-AKI is difficult because by the time patients seek medical attention, most have already developed acute kidney injury. Thus, early recognition is crucial to provide supportive treatment and limit further insults. Current diagnostic criteria for acute kidney injury has limited early detection; however, novel biomarkers of kidney stress and damage have been recently validated for risk prediction and early diagnosis of acute kidney injury in the setting of sepsis. Recent evidence shows that microvascular dysfunction, inflammation, and metabolic reprogramming are 3 fundamental mechanisms that may play a role in the development of S-AKI. However, more mechanistic studies are needed to better understand the convoluted pathophysiology of S-AKI and to translate these findings into potential treatment strategies and add to the promising pharmacologic approaches being developed and tested in clinical trials.

Papillary in situ and intramucosal adenocarcinoma of the lower third of common bile duct. A report and review of the literature.

We report the case of a 37-year-old woman with no relevant medical history. She was admitted to the hospital for epigastric pain related with food intake for 4 days; the pain did not improve with symptomatic management. A laparoscopic cholecystectomy due to acute lithiasic cholecystitis was performed. However, after 4 days, postoperative painless jaundice was evident; thus, endoscopic retrograde cholangiopancreatography was performed, which revealed an amputation of intrapancreatic common bile duct, as well as secondary intra- and extrahepatic bile duct dilatation. Brushing of the distal portion of the common bile duct revealed a well-differentiated adenocarcinoma. Therefore, a Whipple procedure with pylorus preservation was performed. Pathologic diagnosis of a papillary in situ adenocarcinoma with two microscopic foci of microinvasion was established. The pathologic Tumor-Node-Metastasis (TNM) stage was pT1, pN0, pM0, R0. The patient is asymptomatic and disease-free 24 months after surgery. In general, adenocarcinomas of the extrahepatic bile ducts are uncommon and have a poor prognosis. However, symptomatic patients with early disease stages are even rarer and can be cured surgically.

[Causes for consultation in the emergency room among patients with systemic autoimmune diseases]. / Motivos de consulta de pacientes con enfermedades autoinmunes sistémicas en el servicio de urgencias de un hospital terciario.

BACKGROUND: The causes of acute decompensations of patients with systemic autoimmune diseases are not well known. AIM: To describe the causes for consultation in an emergency room of patients with systemic autoimmune diseases. MATERIAL AND METHODS: Review of medical records of patients with systemic autoimmune diseases, aged over 14 years, consulting in an emergency room of a general hospital during three months. RESULTS: In the study period, 166 patients with systemic autoimmune diseases consulted in the emergency room, of a total of 18,153 consultations (0.9%). Patients with rheumatoid arthritis were those that consulted with higher frequency (37%) followed by patients with systemic lupus erythematosus (21%). The most common causes for consultation were cardiovascular diseases in 25%, followed by digestive disorders in 15%. The most common diagnosis was chest pain with suspected ischemic heart disease in 36%. No differences in cardiovascular risk factors were observed between those patients consulting for cardiovascular diseases and those consulting for other causes. CONCLUSIONS: The most common cause of consultation in the emergency room of patients with systemic autoimmune diseases is cardiovascular.

Incidence of obstetric anal sphincter injuries according to the type of forceps used in the Mexican population.

OBJECTIVE: This study describes the frequency of obstetric anal sphincter injuries (OASIS) in patients after instrumental delivery according to the type of forceps used. METHODS: A retrospective comparative cohort study was conducted on patients who underwent instrumental delivery from January 2017 to April 2022. The primary outcome was the presence of OASIS following delivery. Patients were categorized into Cohort A if only rotation forceps were used, Cohort B for only traction forceps, and Cohort C if both types were used sequentially. Statistical analysis was performed with SPSS (IBM, New York, NY) with χ2, Fisher's exact, and analysis of variance testing. A P-value <0.05 was considered significant. RESULTS: OASIS occurred in 45 of 328 instrumental deliveries. OASIS after rotation forceps occurred in 12.9% (n = 8) of cases, after traction forceps in 13.2% (n = 34), and after sequential use of rotation and traction forceps in 37.5% (n = 3) of cases (p = 0.141). An odds ratio (OR) of 0.91 (95% confidence interval [CI] 0.40-2.08) for OASIS was obtained with the use of rotation forceps, 0.81 (95% CI 0.38-1.70) for traction forceps, and 3.97 (95% CI 0.91-17.2) for the sequential use of rotation and traction forceps. CONCLUSION: There were no significant differences in the presence of OASIS comparing traction and rotation forceps. A non-significant trend of higher OASIS following the sequential use of traction and rotation forceps was observed.

Children victims of drug abuser parents: Hair testing as a forensic tool to assess exposure-A cohort of 37 cases from Spain.

Hair testing is a useful tool to investigate suspected pediatric exposure to drugs of abuse. Newborns and young children are at high risk of exposure to drugs of abuse from parents or caregivers who consumed these substances, a fact prosecuted by Spanish authorities as child abuse. A retrospective study based on a cohort of 37 cases classified using several parameters, which involve children under 12 years old, were analyzed at the Drugs Laboratory of the National Institute of Toxicology and Forensic Sciences (Madrid, Spain) between 2009 and 2021. Hair samples were tested for the presence of opiates, cocaine, ketamine, amphetamines, methadone, and cannabis using a gas chromatography-mass spectrometry (GC-MS) method. A 59% of the studied children had ages in the range of 1-3 years old, and in 81% of cases, victims required hospitalization. In 81% of cases (n = 30), hair was submitted only or in combination with other samples, and these were classified in four categories according to analyzed samples: A (only hair), B (hair and blood), C (hair and urine), and D (hair, blood, and urine). The 93.3% of these cases (n = 28) showed a positive result of cannabinoids (THC and CBN in hair and THC-COOH in urine; 71.4% n = 20), cocaine and metabolites (benzoylecgonine and cocaethylene; 46.4% n = 13), opiates (morphine and 6-acetylmorphine), and amphetamines (MDMA and MDMA; 3.10% n = 1). Hair analysis matched positive results in cases where urine screening test was carried out previously (n = 24) and in those cases where blood and/or urine were also submitted (35.6% n = 11). As a conclusion, hair analysis was confirmed as a useful tool to detect previous exposure to acute poisoning events in children.