Macromolecular crowding sensing during osmotic stress in plants.

Osmotic stress conditions occur at multiple stages of plant life. Changes in water availability caused by osmotic stress induce alterations in the mechanical properties of the plasma membrane, its interaction with the cell wall, and the concentration of macromolecules in the cytoplasm. We summarize the reported players involved in the sensing mechanisms of osmotic stress in plants. We discuss how changes in macromolecular crowding are perceived intracellularly by intrinsically disordered regions (IDRs) in proteins. Finally, we review methods for dynamically monitoring macromolecular crowding in living cells and discuss why their implementation is required for the discovery of new plant osmosensors. Elucidating the osmosensing mechanisms will be essential for designing strategies to improve plant productivity in the face of climate change.

Relationship between rate of glucose or propionate infusion and milk protein yield and concentration in dairy cows: A meta-regression.

Although postruminal glucose infusion into dairy cows has increased milk protein yield in some past experiments, the same trend has not been observed in others. A meta-regression of 64 sets of observations from 29 previously published glucose and propionate infusion studies in dairy cattle, treating study and experiment (study) as random effects, was performed to establish the general effects of glucose equivalent (GlcE) infusion rate on milk true protein (MTP) yield and content, if any, and to identify independent, fixed-effect variables that accounted for the changes in MTP yield and content that were observed. Candidate explanatory variables included rate and site of infusion, diet composition and intake, body weight and lactation stage of the cows, and the change in nutrient intake between GlcE and control treatments. Across all studies, according to a model containing only the random effects of study and experiment, GlcE infusion at an average of 954 g/d increased MTP yield by 26 g/d, on average, whereas mean MTP content was not affected. Backward stepwise elimination of potential explanatory variables from a full mixed model produced a final, reduced model for MTP yield that retained a positive, second-order quadratic effect of infusion rate of GlcE and a positive, linear effect of the change in crude protein intake (CPI) between GlcE treatment and control. This change in CPI due to GlcE infusion ranged from -0.546 to 0.173 kg/d in the dataset. The model fit indicated that when CPI was allowed to drop during GlcE infusion, the effect of GlcE on MTP yield was smaller than when CPI was maintained or increased, in a manifestation of the classic protein:energy interaction. The final reduced model for MTP content contained the same explanatory variables as for MTP yield, plus a negative effect of intravenous compared with gastrointestinal infusion. Overall, the meta-analysis revealed that both MTP yield, and content were positively related to GlcE infusion rate and to the change in CPI between glucose treatment and control.

The role of single nucleotide variant rs3819817 of the Histidine Ammonia-Lyase gene and 25-Hydroxyvitamin D on bone mineral density, adiposity markers, and skin pigmentation, in Mexican population.

PURPOSE: Vitamin D (VD) deficiency and osteoporosis have become a global public health problem. A variant in the Histidine Ammonia-Lyase (HAL) gene has been associated with VD levels and bone mineral density (BMD). However, whether this variant has an influence on VD levels and BMD in Mexican adults remain unclear. METHODS: This cross-sectional analysis included 1,905 adults participating in the Health Worker Cohort Study and 164 indigenous postmenopausal women from the Metabolic Analysis in an Indigenous Sample (MAIS) cohort. The rs3819817 variant was genotyped by TaqMan probe assay. Total 25 hydroxyvitamin D levels were measured by DiaSorin Liaison. BMD at the different sites was assessed through dual-energy X-ray absorptiometry. Linear and logistic regression models were performed to evaluate the associations of interest. RESULTS: The prevalence of VD deficiency was 41%, showing differences between sexes. Obesity and skin pigmentation were associated with lower levels of VD in males and females. rs3819817-T allele was associated with low levels of 25-hydroxyvitamin D, VD deficiency, and hip and femoral neck BMD values (g/cm2). We found two interactions with VD levels, one between adiposity and rs3819817-T allele (P = 0.017) and another between skin pigmentation and rs3819817-T allele (P = 0.019). In indigenous postmenopausal women, we observed higher VD levels in the southern region compared to the northern region (P < 0.001); however, we did not observe differences by genotype. CONCLUSION: Our findings confirm that the genetic variant rs3819817 has an essential function in VD levels and BMD and suggests a role in skin pigmentation in the Mexican population.

The BeWo cell line derived from a human placental choriocarcinoma is permissive for respiratory syncytial virus infection.

The respiratory syncytial virus (RSV) is the main pathogen associated with upper respiratory tract infections during early childhood. Vertical transmission of this virus has been suggested in humans, based on observations recorded during animal studies that revealed an association of RSV with persistent structural and functional changes in the developing lungs of the offspring. However, human placentas have not yet been evaluated for susceptibility to RSV infection. In this study, we examined the capacity of RSV to infect a human trophoblast model, the BeWo cell line. Our results suggest that BeWo cells are susceptible to RSV infection since they allow RNA viral replication, viral protein translation, leading to the production of infectious RSV particles. In this report, we demonstrate that a human placenta model system, consisting of BeWo cells, is permissive to RSV infection. Thus, the BeWo cell line may represent a useful model for studies that aim to characterize the events of a possible RSV infection at the human maternal-fetal interface.

Exogenous ß-mannanase supplementation improved immunological and metabolic responses in lactating dairy cows.

Exogenous enzymes have been used to improve nutrient utilization in several species of livestock, particularly swine and poultry. In addition, improved immunological and metabolic traits have been reported in nonruminants. The objective of this study was to determine the effects of ß-mannanase supplementation on milk yield and composition, and immunological and metabolic responses in lactating Holstein dairy cows. Two weeks after calving, 20 Holstein cows (10 multiparous and 10 primiparous) were blocked by parity and assigned to 1 of 2 diets for 182 d. All cows were housed in the same environment and fed the same basal diet. The basal diet of the treatment group was supplemented with ß-mannanase (CTCBio Inc., Seoul, South Korea) at 0.1% of concentrate dry matter. No differences were detected between the control and enzyme supplement groups in milk yield parameters or milk composition. Supplementation of ß-mannanase enzyme reduced blood haptoglobin levels in supplemented multiparous cows compared with controls. Furthermore, nonesterified fatty acid concentration levels tended to be lower in cows fed ß-mannanase, regardless of parity. Neither immunoglobulin G nor milk somatic cell count was affected by ß-mannanase supplementation, regardless of parity. The number of insemination services tended to be lower in cows fed diets supplemented with ß-mannanase. Results from this study suggest that supplementation of ß-mannanase exogenous enzyme could help to reduce instances of systemic inflammation and decrease fat mobilization in lactating Holstein cows. Multiparous cows are considered susceptible to acute infections and inflammation; thus, the enzyme had a greater effect in multiparous cows.

Oxidative Stress in Spinocerebellar Ataxia Type 7 Is Associated with Disease Severity.

Spinocerebellar ataxia type 7 is a neurodegenerative inherited disease caused by a CAG expansion in the coding region of the ATXN7 gene, which results in the synthesis of polyglutamine-containing ataxin-7. Expression of mutant ataxin-7 disturbs different cell processes, including transcriptional regulation, protein conformation and clearance, autophagy, and glutamate transport; however, mechanisms underlying neurodegeneration in SCA7 are still unknown. Implication of oxidative stress in the pathogenesis of various neurodegenerative diseases, including polyglutamine disorders, has recently emerged. We perform a cross-sectional study to determine for the first time pheripheral levels of different oxidative stress markers in 29 SCA7 patients and 28 age- and sex-matched healthy subjects. Patients with SCA7 exhibit oxidative damage to lipids (high levels of lipid hydroperoxides and malondialdehyde) and proteins (elevated levels of advanced oxidation protein products and protein carbonyls). Furthermore, SCA7 patients showed enhanced activity of various anti-oxidant enzymes (glutathione reductase, glutathione peroxidase, and paraoxonase) as well as increased total anti-oxidant capacity, which suggest that activation of the antioxidant defense system might occur to counteract oxidant damage. Strikingly, we found positive correlation between some altered oxidative stress markers and disease severity, as determined by different clinical scales, with early-onset patients showing a more severe disturbance of the redox system than adult-onset patients. In summay, our results suggest that oxidative stress might contribute to SCA7 pathogenesis. Furthermore, oxidative stress biomarkers that were found relevant to SCA7 in this study could be useful to follow disease progression and monitor therapeutic intervention.

Oxidative modifications of foetal LDL-c and HDL-c lipoproteins in preeclampsia.

BACKGROUND: Oxidative modifications have been observed in lipids and proteins in lipoproteins isolated from women with preeclampsia. Thus, newborns could also be susceptible to this damage directly through their mothers. In this study, we evaluated the oxidative profile of LDL-c and HDL-c lipoproteins isolated from the umbilical cord from newborns born to women with preeclampsia. METHODS: Thirty newborns born to women with preeclampsia and thirty newborns born to women with healthy pregnancies were included. Lipid-damage biomarkers, including conjugated dienes, lipohydroperoxides and malondialdehyde, were measured. The reduction of nitroblue tetrazolium, formation of dityrosines, and carbonylation of proteins were assessed as indicators of protein damage. The protective activity of paraoxonase-I on HDL-c particles was evaluated. The total antioxidant capacity and lipid profiles were quantified in plasma. Data were analysed using Student's t-tests and Pearson correlation coefficients. RESULTS: Compared with the control group, the preeclampsia group had an increase in the percentage of lipid damage in both lipoproteins. There was an increase of 23.3 and 19.9% for conjugated dienes, 82.4 and 21.1% for lipohydroperoxides, and 103.8 and 51.5% for malondialdehyde in LDL-c and HDL-c, respectively. However, these infants did not show evident damage in protein oxidation. The activity of the enzyme paraoxonase-I was decreased by 36.2%; by contrast, the total antioxidant capacity was increased by 40% (protein) and 28.8% (non-protein). CONCLUSIONS: The oxidative modifications that occur in HDL-c and LDL-c isolated from newborns from women with preeclampsia are mainly caused by lipoperoxidation processes related to evident paraoxonase-I inactivation. The absence of protein damage is likely linked to an increase in total antioxidant capacity. Therefore, antioxidant support could be helpful in reducing oxidative stress in mother/newborn dyads.

Oxidative profiles of LDL and HDL isolated from women with preeclampsia.

BACKGROUND: Oxidative stress causes biochemical changes in lipids and proteins; these changes can induce damage to the vascular endothelium and create maternal complications that are characteristic of preeclampsia. In this study, we evaluated the oxidative profile of lipoproteins isolated from women with preeclampsia. METHODS: Thirty women diagnosed with preeclampsia and thirty women without preeclampsia were included in the study. Lipid-damage biomarkers, including conjugated dienes, lipohydroperoxides and malondialdehyde, were measured. The reduction of nitroblue tetrazolium, the formation of dityrosines, and the carbonylation of proteins were assessed as indicators of protein damage. The protective activity of HDL-c was evaluated by the paraoxonase-I activity present on the HDL-c particles. Serum lipid profiles were also quantified in both groups. Data were analysed using Student's t test and the Pearson correlation coefficient. RESULTS: Our results demonstrated in PE women evident oxidative changes in the lipids and proteins in HDL-c and LDL-c particles and the activity of the antioxidant enzyme PON-I decreased 59.9%. HDL-c exhibited self-defence, as demonstrated by the negative correlation between paraoxonase-I activity and the formation of lipohydroperoxides in HDL-c (r = -0.3755, p < 0.005). CONCLUSIONS: LDL-c and HDL-c isolated from women with preeclampsia show oxidative damage to lipids and proteins. We propose an oxidative profile based on the oxidation levels indicated by each of the markers used. We also found that paraoxonase-I is inactivated in the presence of lipohydroperoxides. Antioxidant support might be helpful to reduce oxidative stress in patients with preeclampsia. Further investigations are necessary to define the association between antioxidant activities and preeclampsia.

Validation of the instrumented evaluation of spatio-temporal gait parameters in patients with motor incomplete spinal cord injury.

STUDY DESIGN: Observational, descriptive, transversal. OBJECTIVES: To evaluate the validity and reliability of spatio-temporal gait parameters measured by GaitRite in motor incomplete spinal cord-injured (SCI) patients. SETTING: National Institute of Rehabilitation, Mexico city. METHODS: 23 motor subacute and chronic incomplete SCI American Spinal Cord Injury Association Impairment Scale (AIS) D subjects were measured. The 10-meter walking test (10 MWT), 6-minute walking test (6 MWT), Walking Index for Spinal Cord Injury II (WISCI-II), Spinal Cord Independence Measure III (SCIM-III) and the GaitRite evaluation were carried out concurrently in order to determine validity. The 10 MWT and GaitRite evaluation were performed at different occasions in order to determine test-retest reliability. RESULTS: GaitRite offers a valid and reliable way to measure the mobility, symmetry and stability characteristics of gait SCI subjects. GaitRite precision and sensitivity is approximately three times better than clinical tests. Clinical tests cannot address the stability properties of gait. Subjects' higher gait velocity is related to more independence (SCIM-III), lower use of walking aids (WISCI-II), better performance in lower extremities motor score (LEMS) and better gait's mobility. CONCLUSIONS: Spatio-temporal gait parameters measured by GaitRite are both valid and reliable. Further studies are necessary to establish sensitivity of the instrument.

Validation of the instrumented evaluation of spatio-temporal gait parameters in patients with motor incomplete spinal cord injury.

This corrects the article DOI: 10.1038/sc.2017.4.

Application of Focused Ultrasound-Assisted Extraction for the Quantification of Persistent Organic Pollutions in Liver Tissue of Giant Toad (Rhinella marina).

A simple and rapid focused ultrasound extraction method was developed for the determination of Persistent Organic Pollutants (POPs) in liver tissue obtained of giant toad (Rhinella marina) using a gas chromatography coupled to a mass detector with electron impact ionization. The performed method for POPs, was validated in fortified matrix, showing linearity from the LOQ up to 100 ng/mL; LODs and LOQs for each compound were between 1.7 and 4.8 and 3.5-7.5 ng/mL, respectively. Recovery rates were among 79%-116% for POPs determined. Finally, the method was applied in liver samples of giant toads found in a malarial area in Mexico. The sensitivity of the proposed method was good enough to ensure reliable determination of target analytes at concentration levels commonly found in this kind of samples.

Postactivation Potentation Effects From Accommodating Resistance Combined With Heavy Back Squats on Short Sprint Performance.

Applying accommodating resistance combined with isoinertial resistance has been demonstrated to be effective in improving neuromuscular attributes important for sport performance. The main purpose of this study was to determine whether short sprints can be acutely enhanced after several sets of back squats with or without accommodating resistance. Twenty recreationally resistance-trained males (age: 23.3 ± 4.4 years; height: 178.9 ± 6.5 cm; weight: 88.3 ± 10.8 kg) performed pre-post testing on 9.1-m sprint time. Three different interventions were implemented in randomized order between pre-post 9.1-m sprints. On 3 separate days, subjects either sat for 5 minutes (CTRL), performed 5 sets of 3 repetitions at 85% of their 1 repetition maximum (1RM) with isoinertial load (STND), or performed 5 sets of 3 repetitions at 85% of their 1RM, with 30% of the total resistance coming from elastic band tension (BAND) between pre-post 9.1-m sprint testing. Posttesting for 9.1-m sprint time occurred immediately after the last set of squats (Post-Immediate) and on every minute for 4 minutes after the last set of squats (Post-1min, Post-2min, Post-3min, and Post-4min). Repeated-measures analysis of variance statistical analyses revealed no significant changes in sprint time across posttesting times during the CTRL and STND condition. During the BAND condition, sprint time significantly decreased from Post-Immediate to Post-4min (p = 0.002). The uniqueness of accommodating resistance could create an optimal postactivation potentiation effect to increase neuromuscular performance. Coaches and athletes can implement heavy accommodating resistance exercises to their warm-up when improving acute sprint time is desired.

Proinflammatory and anti-inflammatory cytokine profile in pediatric patients with irritable bowel syndrome.

BACKGROUND AND OBJECTIVES: There is evidence that patients with irritable bowel syndrome (IBS) have a low degree of inflammation in the intestinal mucosa. The aim of the study was to evaluate the profile of pro- and anti-inflammatory cytokines in plasma in Mexican pediatric patients with IBS. PATIENTS AND METHODS: Fifteen patients with IBS according to Rome III criteria for childhood and 15 healthy children, matched by age and sex, were included in the study. Plasma levels of tumoral necrosis factor alpha (TNF-α), interleukins 10 and 12 (IL-10, IL-12) and transforming growth factor beta (TGF-ß) were quantified and compared between groups. RESULTS: Plasma levels of IL-10 were lower in patients with IBS (86.07+21.3 pg/mL vs. 118.71+58.62 pg/mL: P=.045) and IL-12 levels were higher in patients with IBS compared to the control group of healthy children (1,204.2±585.9 pg/mL vs. 655.04±557.80 pg/mL; P=.011). The IL-10/IL-12 index was lower in patients with IBS (0.097±0.07 vs. 0.295±0.336; P=.025). Plasma concentration of TGF-ß was higher in patients with IBS (545.67±337.69 pg/mL vs. 208.48±142.21 pg/mL; P=.001). There was no difference in plasma levels of TNF-α between groups. CONCLUSIONS: This study suggests that children with IBS have a state of altered immune regulation. This is consistent with the theory of low-grade inflammatory state in these patients. Further studies are needed to elucidate the role played by these cytokines, specifically TGF-ß in the pathogenesis of IBS.

Multiplex PCR assay for identification of six different Staphylococcus spp. and simultaneous detection of methicillin and mupirocin resistance.

We describe a new, efficient, sensitive, and fast single-tube multiple-PCR protocol for the identification of the most clinically significant Staphylococcus spp. and the simultaneous detection of the methicillin and mupirocin resistance loci. The protocol identifies at the species level isolates belonging to S. aureus, S. epidermidis, S. haemolyticus, S. hominis, S. lugdunensis, and S. saprophyticus.

Insulin polymers in the plasma of obese subjects are associated with elevated levels of carbonyl groups and are decreased by (-)-epicatechin.

We investigated whether oxidative damage and insulin polymerization at a systemic level are associated with the insulin resistance (IR) observed in obese subjects. We evaluated 3 groups (n=16/each) divided according to body mass index (BMI): Normal weight (NW) with a BMI of 18.5-24.9, obese 1 (O1) 30-34.9, and obese 3 (O3)>40 kg/m(2). IR and oxidative damage status of the groups were established by HOMA value and the analysis of biomarkers of oxidative stress in plasma. Insulin polymers in systemic circulation were detected using an antibody specific coupled to magnetic beads, which were incubated in plasma from the study groups. Analysis of magnetic beads by electrophoresis on polyacrylamide gel and silver stain assessed the presence of insulin polymers. The inhibition of polymers formation was studied by the presence of (-)-epicatechin. We demonstrated that O1 and O3 subjects with IR showed higher oxidative damage to their plasma lipids and proteins than NW subjects. This oxidative damage was associated with the presence of insulin polymers in the plasma of the O1 and O3 subjects. This polymer showed a high concentration of carbonyl groups by Western blot, suggesting the participation of oxidative damage in the generation of the polymer. The antioxidant (-)-epicatechin decreased the formation of the insulin polymer, indicating that the prevention of oxidative damage can inhibit insulin polymerization. Our study revealed an association between the presence of carbonyl stress, IR, and insulin polymer formation in obese subjects. This study also demonstrates that the antioxidant (-)-epicatechin inhibits insulin polymerization.

Infertility in rats subjected to genitofemoral nerve section is not associated with testicular damage.

This work was aimed at assessing the relationship between testicular ascent and infertility induced by genitofemoral nerve (GFN) section in rats. Eighteen male rats were assigned to three experimental groups as follows: (i) Group SGFN was subjected to surgical section of genitofemoral nerve; (ii) Group Sham; (iii) Control group. The GFN was cut at puberty (28D), and the contralateral testis removed at 90D, with fertility tests at 120D. At 150D, maturity index, epithelial area and histopathological index of seminiferous tubules of all rats were determined and statistically compared between superior and inferior testicle poles, and between groups. There were no differences in testicular parameters, sperm morphology or sperm concentrations (P > 0.05). Section of NGF interfered with fertility (58.3 ± 15.4 in SGFN versus 83.3 ± 10.5 in Sham) and litter size (6.2 ± 1.1 in SGFN versus 10.7 ± 1.4 in Sham). Cremaster of SGFN group showed early neuropathy. The GFN section induced partial testicular ascent and diminished fertility without damage on testicular morphology or spermatic parameters, because, cremaster could affect the contractibility and ejaculation mechanisms in which it participates. The study of the damage on cremaster induced by an injury on GFN could have an overview of the mechanisms inherent in the testicular ascent induced by this iatrogenic alteration and their potential risks on fertility.

[Association of quality of life perception with sleeping patterns in Chilean older people]. / Asociación entre calidad de vida y cantidad de sueño en adultos mayores de la Región Metropolitana y Región de Valparaíso, Chile.

BACKGROUND: An adequate sleeping pattern recovers physical and mental wellbeing and improves mood. AIM: To determine the association between quality of life and quantity of sleep in older people living in Santiago and Viña del Mar, Chile. MATERIAL AND METHODS: The Spanish versions of the Health Promoting Lifestyles survey and the Pittsburgh Sleep Quality Index were answered by 975 non-disabled participants aged 70.7 ± 7.4 years (61% females). RESULTS: Older adults who slept < 7.0 or > 8.5 hours (h) per night were at higher risk of having lower quality of life scores for all sub-domains, compared with those that slept 7.0 to 8.5 h per night. CONCLUSIONS: A normal sleep pattern in older adults is associated with a better quality of life perception.

The role of oxidative stress in the development of alcoholic liver disease.

BACKGROUND: Alcohol is the most accepted addictive substance worldwide and its consumption is related to multiple health, economic, and social problems. The liver is the organ in charge of ethanol metabolism and it is susceptible to alcohol's toxic effects. OBJETIVOS: To provide a detailed review of the role of oxidative stress in alcoholic liver disease and the mechanisms of damage involved, along with current information on the hepatoprotective effectiveness of the molecules that have been studied. MATERIALS AND METHODS: A search of the PubMed database was conducted using the following keywords oxidative stress, alcoholic liver damage, alcoholic cirrhosis, and antioxidants. There was no time limit for gathering all available information on the subject at hand. RESULTS: According to the literature reviewed, oxidative stress plays an important role in the pathogenesis of alcoholic liver damage. Molecules such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), formed during ethanol metabolism, structurally and functionally modify organic molecules. Consequently, biologic processes are altered and hepatocytes are sensitized to the action of cytokines like tumor necrosis factor-α, as well as to the action of endotoxins, activating signaling pathways such as those controlled by nuclear factor kappa B, extracellular signal regulated kinases, and mitogen activated protein kinase. CONCLUSIONS: Oxidative stress plays an important role in the development of liver damage resulting from alcohol consumption. The molecules that have currently displayed a hepatoprotective effect in preclinical and clinical trials must be studied further so that their effectiveness can be confirmed and they can possibly be used as adjuvant treatments for this disease.

[Adherence to vitamin D supplementation and determinant factors during the first year of life]. / Adherencia a la suplementación con vitamina D y factores determinantes de ella, durante el primer año de vida.

INTRODUCTION: Breastfed infants under one year of age may not get enough vitamin D; therefore a vitamin supplement is needed. The adherence to this policy has not yet been evaluated in Chile. OBJECTIVE: To evaluate the adherence to vitamin D supplementation in children less than one year old and the determinant factors involved. PATIENTS AND METHOD: A cross-sectional study was carried out in three Catholic University Health Network centers. Breastfed infants under one year of age were included in the study. Their parents/guardians filled out a questionnaire about adherence to supplementation and its determinant factors. RESULTS: 170 infants were recruited. 164 of them received supplementation, with a good adherence of 68.9%. The main reason for non-adherence was due to maternal forgetfulness. The identified risk factor for poor adherence was the number of maternal children. CONCLUSIONS: Vitamin D supplementation in Chile reaches high levels, but its adherence is poor. More education to parents on ways to avoid forgetting the supplement is needed as well as on identifying risk factors during medical consultations.

Radiation-induced alteration of apatite on the surface of Mars: first in situ observations with SuperCam Raman onboard Perseverance.

Planetary exploration relies considerably on mineral characterization to advance our understanding of the solar system, the planets and their evolution. Thus, we must understand past and present processes that can alter materials exposed on the surface, affecting space mission data. Here, we analyze the first dataset monitoring the evolution of a known mineral target in situ on the Martian surface, brought there as a SuperCam calibration target onboard the Perseverance rover. We used Raman spectroscopy to monitor the crystalline state of a synthetic apatite sample over the first 950 Martian days (sols) of the Mars2020 mission. We note significant variations in the Raman spectra acquired on this target, specifically a decrease in the relative contribution of the Raman signal to the total signal. These observations are consistent with the results of a UV-irradiation test performed in the laboratory under conditions mimicking ambient Martian conditions. We conclude that the observed evolution reflects an alteration of the material, specifically the creation of electronic defects, due to its exposure to the Martian environment and, in particular, UV irradiation. This ongoing process of alteration of the Martian surface needs to be taken into account for mineralogical space mission data analysis.