Different Conditions Of Stress Research Articles

Abstract P1149: Junctophilin-2 Promotes Cardiomyocyte Survival By Blocking Murf1-mediated Junctin Ubiquitination And Proteasome-dependent Degradation

Background: Junctophilin-2 is required for the development, maturation and integrity of the t-tubule system and the gating stability of RyR2 in cardiomyocytes. This study investigated whether and how junctophilin-2 maintained junctin, a scaffold protein stabilizing RyR2, to prevent cardiomyocyte death under stress. Methods: Cardiomyocytes were exposed to conditions of stress including palmitate, doxorubicin, or hypoxia/re-oxygenation. Adenoviral vectors were employed to manipulate expression of junctophilin-2 and junctin in cardiomyocytes. Molecular/cellular/biochemical analyses were conducted. Results: Different conditions of stress decreased junctophilin-2 expression through aberrant autophagy and concomitantly induced a reduction of junctin protein in cardiomyocytes. Over-expression of junctophilin-2 preserved the protein levels of junctin and attenuated cytosolic Ca 2+ and apoptosis in cardiomyocytes under stress. Knockdown of junctophilin-2 reproduced the detrimental phenotypes of stress in cardiomyocytes. Notably, over-expression of junctin prevented cardiomyocyte death under stress whereas knockdown of junctin offset the protective effects conferred by junctophilin-2 over-expression. Mechanistically, junctophilin-2 blocked MURF1-junctin interaction thereby preventing junctin ubiquitination and proteasome-dependent degradation. Mass spectrometry analysis identified multiple ubiquitination sites on the junctin protein and the non-ubiquitinated junctin mutant (K8R/K102R/K107R/K140R) was resistant to degradation. Conclusions: This study uncovers an unrecognized role of junctophilin-2 in preventing junctin ubiquitination and degradation in maintaining cytosolic Ca 2+ homeostasis. Junctophilin-2 and junctin represent two new survival factors of cardiomyocytes and thus, may be new therapeutic targets for cardiac protection.

Study on stress testing of ferromagnetic materials based on magnetic anisotropy

The stress testing and evaluation of ferromagnetic materials that are widely applied in engineering has always been a focus of, and presented difficulties for, non-destructive testing. As there is still no effective method for detecting the stress of ferromagnetic materials, this paper puts forward the idea of applying the magnetic anisotropy method based on the inverse magnetostriction effect in stress testing of ferromagnetic materials. According to the principle of the magnetic anisotropy method, this paper discusses the development of Mn-Zn ferrite probes of three different structures, the construction of a magnetic anisotropy testing system comprising an excitation system, a signal collecting system and a signal processing system and the way in which a testing experiment was conducted on a 16MnR steel plate specimen under different conditions of stress, frequency and excitation voltage. All three types of probe can effectively determine the stress location of the specimen and present different phenomena and characteristics of the test. According to the experiment, significant correlation is seen between the stress and the magnetic signal, which provides a new idea for stress testing of ferromagnetic materials.

Numerical model of free swelling processes in compacted MX-80 bentonites

This work proposes a formulation to simulate the swelling of compacted bentonites, focusing the analysis on the modelling of the increase of macrostructural void ratio generated by the destructuration of the microstructure under low confinement conditions. First, its formulation is described, highlighting its integration into a generalised constitutive model, which is able to describe the behaviour of compacted bentonites under very different conditions of stress, salinity and water content. After, its scope is assessed, comparing the model predictions with experimental results of free swelling tests performed under different salinity conditions. The results obtained are very satisfactory, especially considering that the proposed swelling model is based on only two material parameters.

Co-expression network analysis of protein phosphatase 2A (PP2A) genes with stress-responsive genes in Arabidopsis thaliana reveals 13 key regulators

Abiotic and biotic stresses adversely affect plant growth and development and eventually result in less yield and threaten food security worldwide. In plants, several studies have been carried out to understand molecular responses to abiotic and biotic stresses. However, the complete circuitry of stress-responsive genes that plants utilise in response to those environmental stresses are still unknown. The protein phosphatase 2A (PP2A) gene has been known to have a crucial role in abiotic and biotic stresses; but how it regulates the stress response in plants is still not known completely. In this study, we constructed gene co-expression networks of PP2A genes with stress-responsive gene datasets from cold, drought, heat, osmotic, genotoxic, salt, and wounding stresses to unveil their relationships with the PP2A under different conditions of stress. The graph analysis identified 13 hub genes and several influential genes based on closeness centrality score (CCS). Our findings also revealed the count of unique genes present in different settings of stresses and subunits. We also formed clusters of influential genes based on the stress, CCS, and co-expression value. Analysis of cis-regulatory elements (CREs), recurring in promoters of these genes was also performed. Our study has led to the identification of 16 conserved CREs.

Numerical model on predicting hydraulic fracture propagation in low-permeability sandstone

Hydraulic fracture propagation is hard to predict due to natural joints and crustal stress. This process may lead to uncontrollable changes in hydrogeological conditions. Therefore, prediction and control of fracture propagation are paramount to permeability increase in ore-bearing reservoir. The coupled fluid-solid model was utilized to predict the hydraulic fracture propagation in low-permeability sandstone of a uranium mine. For this study, the model was modified to allow fractures to propagate randomly by using the cohesive zone method. The simulation was developed on a three-step process. First, geological data required to run the model, including crustal stress, strength and permeability, were assembled. Next, fracture propagation under different conditions of stress and injection volume were simulated. In the final step, experimental data required to validate the model were obtained. The simulation results indicate that the principal stress, distribution and orientation of natural fracture have vital influence on fracture propagation and induced complex fracture network. This work provides a theoretical basis for the application of hydraulic fracture in low-permeability sandstone reservoir and ensures the possibility to predict the generation of complex fracture network.

Agronomic efficiency for nitrogen, phosphorus, and potassium in bean cultivars

The aim of this investigative study was to identify and categorize new bean cultivars regarding their efficiency and responsiveness to nitrogen, phosphorus, and potassium, both individually and simultaneously, as well as to stipulate the cultivars that would suit each niche market based on this classification. Three experiments were conducted in the field separated by nutrients adopting the randomized block design in a factorial scheme (11 x 4) of 11 cultivars in four doses with three replications. Grain yield was the variable investigated and the means were the basis for the classification separated by in four availabilities: low, partial, adequate dose, and nutritional excess. Genetic variability was observed among the bean cultivars for efficiency and responsiveness (agronomic efficiency) to nitrogen, phosphorus, and potassium. The following cultivars: BRS Agreste, BRS Estilo, BRS Notável, and Pérola revealed the greatest values of efficiency and responsive ratings for nitrogen, phosphorus, and potassium, with indications for low and high technological levels. On the contrary, the cultivars BRS Ametista and BRS Sublime based on the efficiency and non-responsive classification showed a low ability to acquire or utilize the nutrients for grain formation. The BRS Pontal cultivar for all three nutrients displayed a high degree of efficiency with a value exceeding the average under different conditions of stress, suggesting that a more rustic cultivar best suits the market niche of small farmers.

Effect of deformation routes on torsion behavior via ACDR process

Plastic flow in continuous incremental bulk metal forming had aroused great interest. However, due to the observational difficulties of each section, the torsion-state plastic flow behavior during axial closed die rolling (ACDR) is usually ignored. Therefore, the flow line in main plastic deformation zone (PDZ) was chosen for detailed investigation in order to unveil the effect of deformation routes on the weight of the circumferential torsion during ACDR process. Then, the modified equation of the equivalent von Mises strain of ACDR process is provided to illustrate the local plastic flow behavior under different deformation routes and different conditions of stress. The results show that the overall strength of PDZ does not significantly change with the loading history, but local plastic flow is enhanced with the increasing deformation time. Severe deformation accumulation in PDZ brings about the increasing radial tension and weakened circumferential torsion axial compression.

Autophagy protects nucleus pulposus cells from cyclic mechanical tension‑induced apoptosis.

Intervertebral disc (IVD) degeneration (IDD) is considered to be a primary cause of lower back pain. Mechanical stress is one of the most important factors affecting IDD. It has been demonstrated that apoptosis is important in the decrease of functional IVD cells, and that mechanical stress influences disc cell apoptosis. Autophagy, an adaptive response of the cells to survival when faced with different conditions of stress, has been documented in IDD. Apoptosis and autophagy share the same stimuli and regulatory proteins, but have different threshold responses. Recently, cyclic mechanical tension(CMT) has been shown to influence IVD cell apoptosis and autophagy. However, the conversion and coordination between apoptosis and autophagy induced by CMT remains to be fully elucidated. In the present study, it was found that CMT with 20%elongation generated by the Flexercell Tension system induced the apoptosis of nucleus pulposus (NP) cells in a time‑dependent manner. When the cells were stretched for >6h, autophagy was increased, and showed a tendency to decrease with the duration of CMT. The autophagic activity of NP cells was partially decreased by 3‑MA and was not significantly regulated by rapamycin. CMT‑induced apoptosis was partially enhanced by the decreased autophagic activity induced by 3‑MA. In addition, the level of reactive oxygen species (ROS) in NP cells induced by CMT was significantly upregulated by 3‑MA. These results suggested that abnormal mechanical stress enhanced disc cell apoptosis and consequently accelerated the process of IDD. Autophagy helps to protect against CMT‑induced apoptosis in disc cells and ROS may be important in this process. These findings are beneficial for further understanding the mechanism of disc cell apoptosis and autophagy.

Study and Analysis of the Failure Mechanism of Tuff Rock based on Laboratory Tests and Three-Dimensional Numerical Modeling

Summary Failure mechanism is different due to stress conditions and rock types, and it is very important to stability of structures. One of the investigations of failure mechanism’s techniques is using triaxial compression test. The aim of the research is determination of failure plane and failure mechanism of Rhyolite Tuff experimentally in different confining pressures and then investigating failure mechanism numerically using three-dimensional finite difference method in details. From the experimental results it was found that with increasing confining pressure, failure angle changes from vertical to oblique. Then numerical model was calibrated with laboratory data and analyzed the details of failure process, which could not be investigated experimentally. Investigations showed that failure process, started with plastic strains at the center of the sample and continued to achieve shear failure plane. Moreover, the results showed that the numerical model is in good agreement with the laboratory tests. Introduction Given the increasing production of minerals, the need to expand and deepen mines is inevitable. With deeper mining, sustainability issues have become more important. All of underground structures have been constructed in rock and the recognition of the rock mechanics issues in relation to the stability of these structures is very important. One of the main topics of rock mechanics, which plays a significant role in the stability of structures, is the rock failure mechanism. Since these structures are located deep in the ground and the behavior of rock failure in different conditions of stress is different, recognizing the rock deformation process under stress conditions can provide a better picture of rock behavior in real conditions .When the distribution and turbulence of the stress creates an imbalance in the rock mass, rock failure occurs by the distribution and interconnection of the micro cracks. Still, there are ambiguities about how rocks are really broken and how the cracks begin to spread. Therefore, prediction of models for fracturing of rocks is very complicated, and it is impossible to predict the failure of rocks with simple models. Therefore, fundamental studies are needed to evaluate the failure process and damage of rocks in different stages of stress. Methodology and Approaches By using uniaxial and triaxial tests, a stress-strain graph was drawn for a rhyolite rock sample. Analyzing the experimental results, it was observed that, with increasing lateral stress, rock resistance increased, and the direction of the fracture plane was maximally illuminated and more angular than the direction of the main stress. It was also found that the behavior of rock with the Mohr Columb's failure criterion is good. For numerical modeling of laboratory experiments, cohesion parameters, internal friction angle, shear modulus, volume modulus and specific gravity were used. To calibrate the model, the meshes and the rate of application applied to the top of the specimen were changed to see the fracture and ultimate strength similar to the laboratory sample in the numerical model. After calibrating the model, the details of the failure stages were carefully examined. Results and Conclusions In numerical models with increasing lateral stress, the angle of deflection compared to the original stress was increased. Tensile plastic strains were formed at the beginning of the loading at the center of the sample. As the loading steps progressed, shear plastic strains started from the corners of the sample and proceeded to the center of the sample. This condition continued until the complete failure of the model and the creation of the plane shear failure. Also, with increasing lateral stress, the initiation of plastic strain occurred in higher stresses and later formed in the sample. Plastic tensile strains appeared at the center of the sample at the beginning of the loading. In the following, the strain began from the two corners of the sample and extended towards the center of the sample. It then extended its path until a plane was formed. Shear and tensile strains were formed in the form of shear-n and (tensile-n) in the sample. These strains may create a shear failure sheet. In fact, joining these strains continuously created a failure plane in the model. The final shear plane was the result of shear-n joining of the shear strains.

تعیین خواص رئولوژیکی گوجهفرنگی تحت شرایط مختلف بارگذاری شبه استاتیکی

مقادیر زیادی از محصول گوجه‌فرنگی طی مراحل مختلف برداشت، انتقال و بسته‌بندی از بین می‌رود. تعیین عوامل موثر بر میزان تغییرشکل گوجه‌فرنگی می‌تواند منجر به کاهش ضایعات محصول شود. اثر برخی از پارامترهای مهم انبارمانی گوجه‌فرنگی مانند بارگذاری شبه استاتیکی در سه سطح (2، 6 و 10 نیوتن)، دمای نگه‌داری در دو سطح (C° 4 و 25) و راستای بارگذاری در دو جهت برای دو رقم گوجه‌فرنگی بر میزان تغییرشکل مورد بررسی قرار گرفتند. آزمایش‌ها در یک دوره 15 روزه، طی آزمایش فاکتوریل در قالب طرح کامل تصادفی بررسی شد. نتایج نشان داد که در دمای C° 25، با افزایش اندازه بار از 2 به 10 نیوتن، مقدار تغییرشکل محصول به میزان 65% افزایش می‌یابد. با کاهش دما از 25 به C° 4، تغییرشکل در بار ثابت 6 نیوتن به میزان 40% کاهش می‌یابد. در شرایط بارگذاری ثابت، مدل رئولوژیکی کلوین عمومی برای تخمین کرنش بر حسب زمان مناسب تشخیص داده شد.

Expression profiling of hsp70 gene during different seasons in goats (Capra hircus) under sub-tropical humid climatic conditions

Thermal stress alters the normal body homeostasis and causes severe detrimental effects on productivity of animals. Heat shock proteins (HSPs) are a ubiquitous class of highly conserved proteins that play a role in cell survival during different conditions of stress. The present study was conducted to detect hsp70 mRNA and protein of stress tolerance and to quantify the expression in different tissues with respect to seasonal variation. The expression of hsp70 gene was observed in four different tissues e.g., liver, heart, spleen & kidney in different climatic conditions. The temperature-humidity index (THI) were observed thrice i.e. in the month of June (THI>72), between September–October (THI=72) and January–February (THI<72). Quantitative real-time PCR (qPCR) & ELISA were used to investigate the relative expression profile of hsp70 gene during different seasons. GAPDH (Glyceraldehyde 3-phosphate dehydrogenase) was used as a housekeeping gene. It was observed that expression of hsp70 gene was higher in liver & kidney tissues as compared to heart and spleen and the expression of hsp70 protein exhibited that the liver and heart tissues showed over expression as compared to kidney and spleen tissues in both the summer & winter season. Heat and cold stress conditions induced over-expression of hsp70. Different tissues have differential sensibilities to thermal stress. The quantification of hsp70 mRNA and protein were both breed and tissue dependent. The phylogenetic analysis of mammalian HSPA4 gene indicated that goats have close relationship (99–99.7%) with sheep, cattle & buffalo and also share homology (94.6–98%) with pig, camel, dog & human. The mRNA and protein expression in the four different tissues of Barbari & Jamunapari show a statistically significant difference (p<0.05) in summer as compared to winter. The above study confirmed that hsp70 expression is breed- and tissue-specific and varies with THI and this relationship may play an imperative role in conferring thermotolerance against heat stress during different seasons.

Viability of Lactobacillus acidophilus Immobilized in Calcium Alginate Spheres and Submitted to Different Conditions of Stress

Viability of Lactobacillus acidophilus Immobilized in Calcium Alginate Spheres and Submitted to Different Conditions of Stress

Lactate transport and receptor actions: Potential roles in inner retinal function and disease

PurposeIn the brain and in adipose tissue activation of the lactate receptor GPR81 is known to promote downregulation of cAMP. Lactate is hereby involved in excitability, metabolism and inflammation. Neurodegenerative diseases in retina may in a similar manner be linked to disturbed lactate homeostasis.MethodsqPCR was performed on retina and brain extracts to investigate whether the lactate receptor GPR81 is expressed in the retina. Immunocytochemistry was performed on primary cell cultures of Müller cells (MC) and retinal ganglion cells (RGC) from mice to evaluate the presence of lactate receptors in neuronal and glial cells in the retina. Lactate assays were made to show the changes in lactate concentrations during different conditions of stress.ResultsGPR81 mRNA was twice as high in retina as in hippocampus or cerebral cortex. Immunocytochemistry indicated lactate receptors in both RGC and MC. Lactate assays showed a decreased release of lactate from MC upon energy restriction. Interestingly, the combination of inhibited mitochondrial function and energy restriction significantly increased the amount of released lactate.ConclusionsThe presence of lactate receptors in the retina as well as the changed levels of lactate in response to stress support the suggestion that lactate could be of great importance in retinal homeostasis and as such in the pathogenesis of inner retinal diseases.

Proteasome stress responses in Schistosoma mansoni.

The proteasome proteolytic system is the major ATP-dependent protease in eukaryotic cells responsible for intracellular protein turnover. Schistosoma mansoni has been reported to contain an ubiquitin-proteasome proteolytic pathway, and many studies have suggested a biological role of proteasomes in the development of this parasite. Additionally, evidence has suggested diversity in proteasome composition under several cellular conditions, and this might contribute to the regulation of its function in this parasite. The proteasomal system has been considered important to support the protein homeostasis during cellular stress. In this study, we described in vitro effects of oxidative stress, heat shock, and chemical stress on S. mansoni adults. Our findings showed that chemical stress induced with curcumin, IBMX, and MG132 modified the gene expression of the proteasomal enzymes SmHul5 and SmUbp6. Likewise, the expression of these genes was upregulated during oxidative stress and heat shock. Analyses of the S. mansoni life cycle showed differential gene expression in sporocysts, schistosomulae, and miracidia. These results suggested that proteasome accessory proteins participate in stress response during the parasite development. The expression level of SmHul5 and SmUbp6 was decreased by 16-fold and 9-fold, respectively, by the chemical stress induced with IBMX, which suggests proteasome disassembly. On the other hand, curcumin, MG132, oxidative stress, and heat shock increased the expression of these genes. Furthermore, the gene expression of maturation proteasome protein (SmPOMP) was increased in stress conditions induced by curcumin, MG132, and H₂O₂, which could be related to the synthesis of new proteasomes. S. mansoni adult worms were found to utilize similar mechanisms to respond to different conditions of stress. Our results demonstrated that oxidative stress, heat shock, and chemical stress modified the expression profile of genes related to the ubiquitin-proteasome system and suggested that the proteasome might be important in the cellular stress response in this parasite.

Plantar pressure and foot temperature responses to acute barefoot and shod running

PurposeIncreased contact pressure and skin friction may lead to higher skin temperature. Here, we hypothesized a relationship between plantar pressure and foot temperature. To elicit different conditions of stress to the foot, participants performed running trials of barefoot and shod running.MethodsEighteen male recreational runners ran shod and barefoot at a self-selected speed for 15 min over different days. Before and immediately after running, plantar pressure during standing (via a pressure mapping system) and skin temperature (using thermography) were recorded.ResultsNo significant changes were found in plantar pressure after barefoot or shod conditions (&lt;i&gt;p&lt;/i&gt; &gt; 0.9). Shod running elicited higher temperatures in the forefoot (by 0.5-2.2°C or 0.1-1.2% compared with the whole foot, &lt;i&gt;p&lt;/i&gt; &lt; 0.01) and midfoot (by 0.9-2.4°C, &lt;i&gt;p&lt;/i&gt; &lt; 0.01). Barefoot running resulted in higher temperature variation in the rearfoot (0.1-10.4%, &lt;i&gt;p&lt;/i&gt; = 0.04). Correlations between skin temperature and plantar pressure were not significant (&lt;i&gt;r&lt;/i&gt; &lt; 0.5 and &lt;i&gt;r&lt;/i&gt; &gt; -0.5, &lt;i&gt;p&lt;/i&gt; &gt; 0.05).ConclusionsThe increase in temperature after the shod condition was most likely the result of footwear insulation. However, variation of the temperature in the rearfoot was higher after barefoot running, possible due to a higher contact load. Changes in temperature could not predict changes in plantar pressure and vice-versa.

Interaction of sea salt and atmospheric pollution alters the OJIP fluorescence transient in the lichen Pseudevernia furfuracea (L.) Zopf

This study investigated the effects of the interaction of sea salt and atmospheric pollution on the photosynthetic system of the lichen Pseudevernia furfuracea (L.) Zopf. v. furfuracea. Thalli of P. furfuracea were transplanted from remote area to different sites subjected to contrasting levels of atmospheric pollution and distance from the coast. Lichen chlorophyll a fluorescence was analysed weekly for one month by means of Handy PEA fluorometer. The effects of sea salt and atmospheric pollution were assessed by OJIP fluorescence transient and its derived fluorescence parameters. We showed that the response of the lichen to the single considered stressing factors was different and it could be detected in terms of variation of the electron flow at different steps of the OJIP fluorescence transient. Our data confirmed that the derived JIP-test parameters are good biomarkers to analyse different conditions of stress in lichens. In particular, we demonstrated that P. furfuracea is more sensitive to atmospheric pollution than to the proximity to the sea and to the interaction of these two factors.

HSP70 as a marker of heat and humidity stress in Tarai buffalo.

Heat and humidity stress is a constant challenge to buffalo rearing under tropical climatic conditions. Heat shock proteins (HSPs) constitute a ubiquitous class of highly conserved proteins that contribute to cell survival during different conditions of stress. The present study was carried out in Tarai buffaloes to study the expression of HSP70 in their peripheral blood mononuclear cells during different seasons and establish it as a marker of heat and humidity stress in buffaloes. Blood samples were collected from each healthy, non-lactating and non-pregnant buffalo above 2years of age, once in the month of January (temperature-humidity index (THI) < 72) and in the month of May (THI > 72). Blood samples were also collected during October (THI = 72) to be used as calibrator/control. Real-time PCR was used to profile the HSP70 gene expression in the peripheral blood mononuclear cells (PBMCs). The relative expression values of HSP70 in Tarai buffalo was found to be significantly higher (P < 0.05) during summer season (2.37 ± 0.12) as compared to winter season (0.29 ± 0.04). The expression positively correlated with changes in physiological parameters like respiration rate (RR), pulse rate (PR) and rectal temperature (RT). In conclusion, it can be said that RR and HSP70 may act as characteristic physiological and cellular markers of heat and humidity stress in buffaloes.

Stress Management Tools for Preventing Burnout Phenomenon at Teachers from Special Education

Literature has often discussed the relationship between teaching as profession and a high level of stress. Personal work style, maintaining discipline in the classroom, the need to adapt to changes in educational system, inadequate working conditions are only few determinants identified. Our study aims are to specify the relationship between defense/coping mechanisms in different conditions of stress developed by special education teachers and the burnout phenomenon. Scales for identifying the satisfaction at work, the level of stress, the defense mechanisms and the Maslach Burnout Inventory were used. We applied the mentioned instruments for a group of 120 teachers active within special education system.

From 'JUNK' to Just Unexplored Noncoding Knowledge: the case of transcribed Alus

Non-coding RNAs (ncRNAs) are increasingly being implicated in diverse functional roles. Majority of these ncRNAs have their origin in the repetitive elements of genome. Significantly, increase in genomic complexity has been correlated with increase in repetitive content of the genome. Primate-specific Alu repeats, belonging to SINE class of repeats, is the most abundant repeat class inhabiting the human genome. Of the many possible functional roles of Alu repeats, they have been shown to modulate human transcriptome by virtue of harboring diverse array of functional RNA pol II TFBS, cryptic splice-site-mediated Alu exonization and as probable miRNA targets. Retro-transposition of Alu harboring TFBS has shaped up gene-specific regulatory networks. Alu exonized transcripts are raw material for dsRNA-mediated A-I editing leading to nuclear retention of transcripts and change in miRNA target. miRNA targets within Alu may titrate the effective miRNA or transcript concentration, thus acting as 'miRNA sponge'. Differential levels of Alu RNA during different conditions of stress also await clear functional understanding. These have contributed toward evolution of complex regulatory repertoire leading to the evolution of primate-specific functions. Recent reports of co-localization of pol II and pol III binding sites near the gene and elsewhere in the genome, increase the possibility of dynamic co-ordination between both pol II and pol III determining the ultimate transcriptional outcome. Dynamic and functional Alu repeats seem to be centrally placed to modulate the transcriptional landscape of human genome.

Assessing Distribution Patterns, Extent, and Current Condition of Northwest Mexico Mangroves

This study contributes to the worldwide effort to update the status of mangroves, assessing a large mangrove distribution area in Mexico by analyzing Landsat MSS from the early 1970s and TM imagery from 2005. Four states (Baja California Sur, Sonora, Sinaloa, and Nayarit) integrate the northwest region of Mexico, where the mangrove area was estimated to be around 180,000 ha on both dates, with a reduction of about 2% by 2005. Nayarit by itself had a large decrease (>10,000 ha), while the other states increased their mangrove extent from 4 to 15%. However, this increase was probably a consequence of improved satellite capabilities in 2005 rather than mangrove expansion. Mangrove condition, measured through a normalized difference vegetation index (NDVI), was categorized into four types based in the index value distributions. Type 1, representing the poorest condition, included values below the first quartile (Q1), while Type 4, the best condition, was indicated by values above Q3. One of the intermediate categories (Type 3) was dominant, accounting for >40% of the total mangrove surface in both the 1970s and 2005. Mangrove systems in northwest Mexico have different conditions of stress, and thus different management strategies should be identified to preserve and maintain those systems.