Chromatic acclimation in cyanobacteria renders robust photosynthesis and fitness in dynamic light environment: Recent advances and future perspectives.

Cyanobacteria are photoautotrophic organisms that use light and water as a source of energy and electrons, respectively, to fix atmospheric carbon dioxide and release oxygen as a by-product during photosynthesis. However, photosynthesis and fitness of organisms are challenged by seasonal and diurnal fluctuations in light environments. Also, the distribution of cyanobacteria in a water column is subject to changes in the light regime. The quality and quantity of light change significantly in low and bright light environments that either limit photochemistry or result in photoinhibition due to an excess amount of light reaching reaction centers. Therefore, cyanobacteria have to adjust their light-harvesting machinery and cell morphology for the optimal harvesting of light. This adjustment of light-harvesting involves remodeling of the light-harvesting complex called phycobilisome or incorporation of chlorophyll molecules such as chlorophyll d and f into their light-harvesting machinery. Thus, photoacclimation responses of cyanobacteria at the level of pigment composition and cell morphology maximize their photosynthetic ability and fitness under a dynamic light environment. Cyanobacteria exhibit different types of photoacclimation responses that are commonly known as chromatic acclimation (CA). In this work, we discuss different types of CA reported in cyanobacteria and present a molecular mechanism of well-known type 3 CA where phycoerythrin and phycocyanin of phycobilisome changes according to light signals. We also include other aspects of type 3 CA that have been recently studied at a molecular level and highlight the importance of morphogenes, cytoskeleton, and carboxysome proteins. In summary, CA gives a unique competitive benefit to cyanobacteria by increasing their resource utilization ability and fitness.

Computational studies on photolyase (Phr) proteins of cyanobacteria.

Photolyases (Phrs) are enzymes that utilize the blue/ultraviolet (UV-A) region of light for repairing UV-induced cyclopyramidine dimers. We studied Phr groups by bioinformatic analyses as well as active-site and structural modeling. Analysis of 238 amino acid sequences from 85 completely sequenced cyanobacterial genomes revealed five classes of Phrs, CPD Gr I, 6-4 Phrs/cryptochrome, Cry-DASH, Fe-S bacteria Phrs, and a group with fewer amino acids (276-385) in length. The distribution of Phr groups in cyanobacteria belonging to the order Synechococcales was found to be influenced by the habitats of the organisms. Class V Phrs are exclusively present in cyanobacteria. Unique motifs and binding sites were reported in groups II and III. The Fe-S protein binding site was only present in group V and the active site residues and putative CPD/6-4PP binding residues are charged amino acids present on the surface of the proteins. The majority of hydrophilic amino acid residues were present on the surface of the Phrs. Sequence analysis confirmed the diverse nature of Phrs, although sequence diversity did not affect the overall three-dimensional structure. Protein-ligand interaction analysis identified novel CPD/6-4PP binding sites on Phrs. This structural information of Phrs can be used for the preparation of efficient Phr-based formulations.

Kavain Reduces Porphyromonas gingivalis-Induced Adipocyte Inflammation: Role of PGC-1α Signaling.

A link between obesity and periodontitis has been suggested because of compromised immune response and chronic inflammation in obese patients. In this study, we evaluated the anti-inflammatory properties of Kavain, an extract from Piper methysticum, on Porphyromonas gingivalis-induced inflammation in adipocytes with special focus on peroxisome proliferation-activated receptor γ coactivator α (PGC-1α) and related pathways. The 3T3-L1 mouse preadipocytes and primary adipocytes harvested from mouse adipose tissue were infected with P. gingivalis, and inflammation (TNF-α; adiponectin/adipokines), oxidative stress, and adipogenic marker (FAS, CEBPα, and PPAR-γ) expression were measured. Furthermore, effect of PGC-1α knockdown on Kavain action was evaluated. Results showed that P. gingivalis worsens adipocyte dysfunction through increase of TNF-α, IL-6, and iNOS and decrease of PGC-1α and adiponectin. Interestingly, although Kavain obliterated P. gingivalis-induced proinflammatory effects in wild-type cells, Kavain did not affect PGC-1α-deficient cells, strongly advocating for Kavain effects being mediated by PGC-1α. In vivo adipocytes challenged with i.p. injection of P. gingivalis alone or P. gingivalis and Kavain displayed the same phenotype as in vitro adipocytes. Altogether, our findings established anti-inflammatory and antioxidant effects of Kavain on adipocytes and emphasized protective action against P. gingivalis-induced adipogenesis. The use of compounds such as Kavain offer a portal to potential therapeutic approaches to counter chronic inflammation in obesity-related diseases.

Epoxyeicosatrienoic intervention improves NAFLD in leptin receptor deficient mice by an increase in PGC1α-HO-1-PGC1α-mitochondrial signaling.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and is considered to be an inflammatory disorder characterized by fatty acid accumulation, oxidative stress, and lipotoxicity. We have previously reported that epoxyeicosatrienoic acid-agonist (EET-A) has multiple beneficial effects on cardiac, renal and adipose tissue function while exhibiting both anti-inflammatory and anti-oxidant activities. We hypothesized that EET-A intervention would play a central role in attenuation of obesity-induced steatosis and hepatic fibrosis that leads to NAFLD. METHODS: We studied the effect of EET-A on fatty liver using db/db mice as a model of obesity. Mice were fed a high fat diet (HFD) for 16 weeks and administered EET-A twice weekly for the final 8 weeks. RESULTS: db/db mice fed HFD significantly increased hepatic lipid accumulation as manifested by increases in NAS scores, hepatic fibrosis, insulin resistance, and inflammation, and decreases in mitochondrial mitofusin proteins (Mfn 1/2) and anti-obesity genes Fibroblast growth factor 21 (FGF21) and Cellular Repressor of E1A-Stimulated Genes 1 (CREG1). EET-A administration reversed the decrease in these genes and reduced liver fibrosis. Knockout of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in EET-A treated mice resulted in a reversal of the beneficial effects of EET-A administration. CONCLUSIONS: EET-A intervention diminishes fatty acid accumulation, fibrosis, and NFALD associated with an increase in HO-1-PGC1α and increased insulin receptor phosphorylation. A pharmacological strategy involving EETs may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NAFLD.

Oxidative stress measurement in different morphological forms of wild-type and mutant cyanobacterial strains: Overcoming the limitation of fluorescence microscope-based method.

Monitoring of oxidative stress caused by a wide range of reactive oxygen species (ROS) is essential to have an idea about the fitness and growth of photosynthetic organisms. The imaging-based oxidative stress measurement in cyanobacteria using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) dye has the limitation of small sample size as the only selected number of cells are analyzed to measure the ROS levels. Here, we developed a method for oxidative stress measurement by DCFH-DA and flow cytometer (FCM) using unicellular Synechococcus elongatus PCC 7942 and filamentous Fremyella diplosiphon BK14 cyanobacteria. F. diplosiphon BK14 inherently possess high levels of ROS and showed higher sensitivity to hydrogen peroxide treatment in comparison to S. elongatus PCC 7942. We successfully measured oxidative stress in glutaredoxin lacking strain (Δgrx3) of S. elongatus PCC 7942, and wild-type Synechocystis sp. PCC 6803 using FCM based method. Importantly, ROS were not detected in these two strains of cyanobacteria by fluorescence microscope-based method due to their small spherical morphology. Δgrx3 strain showed high ROS levels in comparison to its wild-type strain. Treatment of abiotic factors such as high PAR in wild-type and Δgrx3 strains of S. elongatus PCC 7942, low PAR or low PAR + UVR in wild-type S. elongatus PCC 7942, and high PAR or high PAR + NaCl in Synechocystis sp. PCC 6803 increased oxidative stress. In summary, the FCM based method can measure ROS levels produced due to physiological conditions associated with genetic changes or abiotic stress in a large population of cells regardless of their morphology. Therefore, the present study shows the usefulness of the method in monitoring the health of organisms in a large scale cultivation system.

Cold Press Pomegranate Seed Oil Attenuates Dietary-Obesity Induced Hepatic Steatosis and Fibrosis through Antioxidant and Mitochondrial Pathways in Obese Mice.

AIM: Obesity is associated with metabolic syndrome, hypertension, dyslipidemia, nonalcoholic fatty liver disease (NAFLD), and type 2 diabetes. In this study, we investigated whether the dietary supplementation of pomegranate seed oil (PSO) exerted a protective effect on liver lipid uptake, fibrosis, and mitochondrial function in a mouse model of obesity and insulin resistance. METHOD: In this in vivo study, eight-week-old C57BL/6J male mice were fed with a high fat diet (HFD) for 24 weeks and then were divided into three groups as follows: group (1) Lean; group (n = 6) (2) HF diet; group (n = 6) (3) HF diet treated with PSO (40 mL/kg food) (n = 6) for eight additional weeks starting at 24 weeks. Physiological parameters, lipid droplet accumulation, inflammatory biomarkers, antioxidant biomarkers, mitochondrial biogenesis, insulin sensitivity, and hepatic fibrosis were determined to examine whether PSO intervention prevents obesity-associated metabolic syndrome. RESULTS: The PSO group displayed an increase in oxygen consumption, as well as a decrease in fasting glucose and blood pressure (p < 0.05) when compared to the HFD-fed mice group. PSO increased both the activity and expression of hepatic HO-1, downregulated inflammatory adipokines, and decreased hepatic fibrosis. PSO increased the levels of thermogenic genes, mitochondrial signaling, and lipid metabolism through increases in Mfn2, OPA-1, PRDM 16, and PGC1α. Furthermore, PSO upregulated obesity-mediated hepatic insulin receptor phosphorylation Tyr-972, p-IRB tyr1146, and pAMPK, thereby decreasing insulin resistance. CONCLUSIONS: These results indicated that PSO decreased obesity-mediated insulin resistance and the progression of hepatic fibrosis through an improved liver signaling, as manifested by increased insulin receptor phosphorylation and thermogenic genes. Furthermore, our findings indicate a potential therapeutic role for PSO in the prevention of obesity-associated NAFLD, NASH, and other metabolic disorders.

High-fat diet-induced obesity and insulin resistance in CYP4a14-/- mice is mediated by 20-HETE.

20-Hydroxyeicosatetraenoic acid (20-HETE) has been shown to positively correlate with body mass index, hyperglycemia, and plasma insulin levels. This study seeks to identify a causal relationship between 20-HETE and obesity-driven insulin resistance. Cyp4a14-/- male mice, a model of 20-HETE overproduction, were fed a regular or high-fat diet (HFD) for 15 wk. 20-SOLA [2,5,8,11,14,17-hexaoxanonadecan-19-yl 20-hydroxyeicosa-6( Z),15( Z)-dienoate], a 20-HETE antagonist, was administered from week 0 or week 7 of HFD. HFD-fed mice gained significant weight (16.7 ± 3.2 vs. 3.8 ± 0.35 g, P < 0.05) and developed hyperglycemia (157 ± 3 vs. 121 ± 7 mg/dl, P < 0.05) and hyperinsulinemia (2.3 ± 0.4 vs. 0.5 ± 0.1 ng/ml, P < 0.05) compared with regular diet-fed mice. 20-SOLA attenuated HFD-induced weight gain (9.4 ± 1 vs. 16.7 ± 3 g, P < 0.05) and normalized the hyperglycemia (157 ± 7 vs. 102 ± 5 mg/dl, P < 0.05) and hyperinsulinemia (1.1 ± 0.1 vs. 2.3 ± 0.4 ng/ml, P < 0.05). The impaired glucose homeostasis and insulin resistance in HFD-fed mice evidenced by reduced insulin and glucose tolerance were also ameliorated by 20-SOLA. Circulatory and adipose tissue 20-HETE levels significantly increased in HFD-fed mice correlating with impaired insulin signaling, including reduction in insulin receptor tyrosine (Y972) phosphorylation and increased serine (S307) phosphorylation of the insulin receptor substrate-1 (IRS-1). 20-SOLA treatments prevented changes in insulin signaling. These findings indicate that 20-HETE contributes to HFD-induced obesity, insulin resistance, and impaired insulin signaling.

EET enhances renal function in obese mice resulting in restoration of HO-1-Mfn1/2 signaling, and decrease in hypertension through inhibition of sodium chloride co-transporter.

BACKGROUND: We have previously reported that epoxyeicosatrienoic acid (EET) has multiple beneficial effects on renal and adipose tissue function, in addition to its vasodilatory action; it increases insulin sensitivity and inhibits inflammation. In an examination of the signaling mechanisms by which EET reduces renal and peri-renal fat function, we hypothesized that EET ameliorates obesity-induced renal dysfunction by improving sodium excretion, reducing the sodium-chloride cotransporter NCC, lowering blood pressure, and enhancing mitochondrial and thermogenic gene levels in PGC-1α dependent mice. METHODS: EET-agonist treatment normalized glucose metabolism, renal ENaC and NCC protein expression, urinary sodium excretion and blood pressure in obese (db/db) mice. A marked improvement in mitochondrial integrity, thermogenic genes, and PGC-1α-HO-1-adiponectin signaling occurred. Knockout of PGC-1α in EET-treated mice resulted in a reversal of these beneficial effects including a decrease in sodium excretion, elevation of blood pressure and an increase in the pro-inflammatory adipokine nephroblastoma overexpressed gene (NOV). In the elucidation of the effects of EET on peri-renal adipose tissue, EET increased adiponectin, mitochondrial integrity, thermogenic genes and decreased NOV, i.e. "Browning' peri-renal adipose phenotype that occurs under high fat diets. Taken together, these data demonstrate a critical role of an EET agonist in the restoration of healthy adipose tissue with reduced release of inflammatory molecules, such as AngII and NOV, thereby preventing their detrimental impact on sodium absorption and NCC levels and the development of obesity-induced renal dysfunction.

Ablation of soluble epoxide hydrolase reprogram white fat to beige-like fat through an increase in mitochondrial integrity, HO-1-adiponectin in vitro and in vivo.

We have shown that epoxyeicosatrienoic acids (EETs), specifically 11,12- and 14,15-EETs, reduce adipogenesis in human mesenchymal stem cells and mouse preadipocytes (3T-3L1). In this study, we explore the effects of soluble epoxide hydrolase (sEH) deletion on various aspects of adipocyte-function, including programing for white vs. beige-like fat, and mitochondrial and thermogenic gene-expressions. We further hypothesize that EETs and heme-oxygenase 1 (HO-1) form a synergistic, functional module whose effects on adipocyte and vascular function is greater than the effects of sEH deletion alone. In in vitro studies, we examined the effect of sEH inhibitors on MSC-derived adipocytes. MSC-derived adipocytes exposed to AUDA, an inhibitor of sEH, exhibit an increased number of small and healthy adipocytes, an effect reproduced by siRNA for sEH. in vivo studies indicate that sEH deletion results in a significant decrease in adipocyte size, inflammatory adipokines NOV, TNFα, while increasing adiponectin (p < 0.05). These findings are associated with a decrease in body weight (p < 0.05), and visceral fat (p < 0.05). Importantly, sEH deletion was associated with a significant increase in Mfn1, COX 1, UCP1 and adiponectin (p < 0.03). sEH deletion was manifested by a significant increase in EETs isomers 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET and an increased EETs/DHETEs ratio. Notably, activation of HO-1 gene expression further increased the levels of EETs, suggesting that the antioxidant HO-1 system protects EETs from degradation by ROS. These results are novel in that sEH deletion, while increasing EET levels, resulted in reprograming of white fat to express mitochondrial and thermogenic genes, a phenotype characteristic of beige-fat. Thus, EETs agonist(s) and sEH inhibitors may have therapeutic potential in the treatment of metabolic syndrome and obesity.

Histology with immunohistochemistry of the fistula region in female anorectal malformation: Can it be used for neo-anus reconstruction?

AIM: Female anorectal malformation is characterised by communication to the exterior by a fistula. There are conflicting reports of the presence of normal anus in the fistula region. This study was undertaken to assess the histopathology and immunohistochemical correlation of the terminal portion of the fistula in female patients and suitability of fistula incorporation in the reconstruction of the neo-anus. METHODS: This prospective study included 13 patients of female anorectal malformation. Of these, seven had a vestibular fistula (VF), and the rest had an anterior ectopic anus (AEA). Histopathology of the fistula region was undertaken, along with immunohistochemistry. Various findings were evaluated. RESULTS: Of seven VF patients, four showed atrophic or disrupted internal sphincter smooth muscle, whereas the remaining three showed hypertropic internal sphincteric smooth muscle. Six patients showed hypertrophic nerve bundle. Five VF patients showed subepithelial fibrosis, and none of them showed ganglion cells. Of six patients of AEA, internal sphincteric smooth muscle was normal in five. It was hypertrophic in one patient. Transitional epithelium was present in four patients. All patients showed hypertrophic nerve bundle and aganglionosis. Subepithelial fibrosis was observed in six patients. CONCLUSION: The fistula region in VF and AEA patients appears to be an abnormal structure. Rather than preservation of the terminal fistulous region, resection followed by anoplasty may be a viable option.

EET intervention on Wnt1, NOV, and HO-1 signaling prevents obesity-induced cardiomyopathy in obese mice.

We have previously reported that epoxyeicosatrienoic acid (EET) has multiple beneficial effects on vascular function; in addition to its antiapoptotic action, it increases insulin sensitivity and inhibits inflammation. To uncover the signaling mechanisms by which EET reduces cardiomyopathy, we hypothesized that EET infusion might ameliorate obesity-induced cardiomyopathy by improving heme oxygenase (HO)-1, Wnt1, thermogenic gene levels, and mitochondrial integrity in cardiac tissues and improved pericardial fat phenotype. EET reduced levels of fasting blood glucose and proinflammatory adipokines, including nephroblastoma overexpressed (NOV) signaling, while increasing echocardiographic fractional shortening and O2 consumption. Of interest, we also noted a marked improvement in mitochondrial integrity, thermogenic genes, and Wnt 1 and HO-1 signaling mechanisms. Knockout of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in EET-treated mice resulted in a reversal of these beneficial effects including a decrease in myocardial Wnt1 and HO-1 expression and an increase in NOV. To further elucidate the effects of EET on pericardial adipose tissues, we observed EET treatment increases in adiponectin, PGC-1α, phospho-AMP-activated protein kinase, insulin receptor phosphorylation, and thermogenic genes, resulting in a "browning" pericardial adipose phenotype under high-fat diets. Collectively, these experiments demonstrate that an EET agonist increased Wnt1 and HO-1 signaling while decreasing NOV pathways and the progression of cardiomyopathy. Furthermore, this report presents a portal into potential therapeutic approaches for the treatment of heart failure and metabolic syndrome.NEW & NOTEWORTHY The mechanism by which EET acts on obesity-induced cardiomyopathy is unknown. Here, we describe a previously unrecognized function of EET infusion that inhibits nephroblastoma overexpressed (NOV) levels and activates Wnt1, hence identifying NOV inhibition and enhanced Wnt1 expression as novel pharmacological targets for the prevention and treatment of cardiomyopathy and heart failure.Listen to this article's corresponding podcast at http://ajpheart.physiology.org/content/early/2017/05/31/ajpheart.00093.2017.

PGC-1 alpha regulates HO-1 expression, mitochondrial dynamics and biogenesis: Role of epoxyeicosatrienoic acid.

BACKGROUND/OBJECTIVES: Obesity is a risk factor in the development of type 2 diabetes mellitus (DM2), which is associated with increased morbidity and mortality, predominantly as a result of cardiovascular complications. Increased adiposity is a systemic condition characterized by increased oxidative stress (ROS), increased inflammation, inhibition of anti-oxidant genes such as HO-1 and increased degradation of epoxyeicosatrienoic acids (EETs). We previously demonstrated that EETs attenuate mitochondrial ROS. We postulate that EETs increase peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), which controls mitochondrial function, oxidative metabolism and induction of HO-1. METHODS: Cultured murine adipocytes and mice fed a high fat (HF) diet were used to assess functional relationship between EETs, HO-1 and (PGC-1α) using an EET analogue (EET-A) and lentivirus to knock down the PPARGC1A gene. RESULTS: EET-A increased PGC-1α and HO-1 in cultured adipocytes and increased the expression of genes involved in thermogenesis and adipocyte browning (UCP1 and PRDM16, respectively). PGC-1α knockdown prevented EET-A-induced HO-1expression, suggesting that PGC-1α is upstream of HO-1. MRI data obtained from fat tissues showed that EET-A administration to mice on a HF diet significantly reduced total body fat content, subcutaneous and visceral fat deposits and reduced the VAT: SAT ratio. Moreover EET-A normalized the VO2 and RQ (VCO2/VO2) in mice fed a HF diet, an effect that was completely prevented in PGC-1α deficient mice. In addition, EET-A increased mitochondrial biogenesis and function as measured by OPA1, MnSOD, Mfn1, Mfn2, and SIRT3, an effect that was inhibited by knockdown of PGC-1α. CONCLUSION: Taken together, our findings show that EET-A increased PGC-1α thereby increasing mitochondrial viability, increased fusion potential thereby providing metabolic protection and increased VO2 consumption in HF-induced obesity in mice, thus demonstrating that the EET-mediated increase in HO-1 levels require PGC-1α expression.

Oxidized HDL is a potent inducer of adipogenesis and causes activation of the Ang-II and 20-HETE systems in human obese females.

BACKGROUND: Oxidized-HDL (OX-HDL) has been reported to increase coronary events in obese patients; however, OX-HDL has not been studied in subjects with the metabolic syndrome. A high body mass index (BMI) correlates positively with higher levels of metabolic syndrome biomarkers including vasoconstrictors and adipokines. We hypothesize that a subject with a high BMI would present with higher levels of OX-HDL, 20-HETE and Angiotensin II (Ang II) with a reciprocal reduction in serum adiponectin. METHODS: Female subjects with a BMI of 17-25 and a BMI of 30-40, without overt cardiovascular disease, were enrolled in the study. All patients had a history and physical exam documenting the absence of signs and symptoms of cardiovascular disease. Appropriate screening was done and documented. Blood pressure was taken at two discrete points. The BP data are presented as the average. Changes in the relationship between BMI, OX-HDL, 20-HETE, Ang II, TNFα, isoprostane and adiponectin were examined. In addition, the effects of OX-HDL, 20-HETE and Ang II on adipogenesis were examined in human MSC derived adipocytes. RESULTS: Subjects with a high BMI>30 displayed an increase in OX-HDL and isoprostane (P<0.05) compared to those with the lower BMI<25 which was associated with an increase in Ang II and 20-HETE (p<0.05). Serum TNFα levels increased in subjects with a high BMI, compared to subjects with the lower BMI (p<0.05). In contrast, adiponectin levels were increased in subjects with a low BMI compared to obese subjects (p<0.05). In MSC derived adipocytes OX-HDL increased adipogenesis 6 fold at a concentration of 50ng compared to untreated adipocytes. Adipocytes treated with Ang II and 20-HETE also displayed increased adipogenesis (p<0.05), which was attenuated by endogenous increases of the anti-oxidant heme oxygenase-1. Our study demonstrates that OX-HDL presents a unique inflammatory biomarker profile in obese females with the metabolic syndrome at risk for developing cardiovascular disease. CONCLUSIONS: Females with increased BMI (30-40) exhibit a marked increase in OX-HDL and isoprostane levels, which was associated with an increase in 20-HETE, TNF α and Ang II and decreased levels of adiponectin when compared to a group with a low BMI. OX-HDL had a more powerful adipogenic effect when compared to 20-HETE and Ang II. Our study demonstrates that OX-HDL presents a unique inflammatory biomarker profile in obese females with the metabolic syndrome at risk for developing cardiovascular disease. This represents a novel mechanism by which females with a high BMI and controlled blood pressure remain "at risk" for the development of the metabolic syndrome as a result of increased adipogenesis by OX-HDL and activation of the 20-HETE and Ang II systems.

Morphogenes bolA and mreB mediate the photoregulation of cellular morphology during complementary chromatic acclimation in Fremyella diplosiphon.

Photoregulation of pigmentation during complementary chromatic acclimation (CCA) is well studied in Fremyella diplosiphon; however, mechanistic insights into the CCA-associated morphological changes are still emerging. F. diplosiphon cells are rectangular under green light (GL), whereas cells are smaller and spherical under red light (RL). Here, we investigate the role of morphogenes bolA and mreB during CCA using gene expression and gene function analyses. The F. diplosiphon bolA gene is essential as its complete removal from the genome was unsuccessful. Depletion of bolA resulted in slow growth, morphological defects and the accumulation of high levels of reactive oxygen species in a partially segregated ΔbolA strain. Higher expression of bolA was observed under RL and was correlated with lower expression of mreB and mreC genes in wild type. In a ΔrcaE strain that lacks the red-/green-responsive RcaE photoreceptor, the expression of bolA and mre genes was altered under both RL and GL. Observed gene expression relationships suggest that mreB and mreC expression is controlled by RcaE-dependent photoregulation of bolA expression. Expression of F. diplosiphon bolA and mreB homologues in Escherichia coli demonstrated functional conservation of the encoded proteins. Together, these studies establish roles for bolA and mreB in RcaE-dependent regulation of cellular morphology.

Salinity impacts photosynthetic pigmentation and cellular morphology changes by distinct mechanisms in Fremyella diplosiphon.

Fremyella diplosiphon is a freshwater cyanobacterium that exhibits complementary chromatic adaptation (CCA), which allows the organism to alter its pigmentation and cellular morphology to maximally harvest available green light (GL) and red light (RL) at different depth levels in its aquatic ecosystem. We tested the effect of salinity on CCA-associated pigment and morphological changes in F. diplosiphon. Sodium chloride (NaCl) salt at a concentration of 200mM was found to maximally inhibit growth, chlorophyll levels, and accumulation of phycoerythrin (PE) and phycocyanin (PC) under GL and RL, respectively. NaCl also affected cellular morphology resulting in a larger cell size under both light conditions. Cell length decreased while width increased under GL in the presence of salt, and both cell length and width were increased under RL with salt. The addition of osmoprotectant glycine betaine (GB) to the growth medium in the presence of salt resulted in a reversion of the morphology to that of cells growing in the absence of salt, whereas GB treatment in the presence of salt did not have a major effect on growth or on PE and PC biosynthesis or accumulation. Thus, salt affects cellular morphology due to osmotic stress, while pigmentation is likely affected by ionic toxicity. Understanding the distinct mechanisms of salt-mediated changes on pigmentation and morphology may increase the suitability of strains such as F. diplosiphon, which harbor pigments that allow growth in low light and shaded environments, for adaptation as energy strains.

Temporal dynamics of changes in reactive oxygen species (ROS) levels and cellular morphology are coordinated during complementary chromatic acclimation in Fremyella diplosiphon.

Fremyella diplosiphon alters the phycobiliprotein composition of its light-harvesting complexes, i.e., phycobilisomes, and its cellular morphology in response to changes in the prevalent wavelengths of light in the external environment in a phenomenon known as complementary chromatic acclimation (CCA). The organism primarily responds to red light (RL) and green light (GL) during CCA to maximize light absorption for supporting optimal photosynthetic efficiency. Recently, we found that RL-characteristic spherical cell morphology is associated with higher levels of reactive oxygen species (ROS) compared to growth under GL where lower ROS levels and rectangular cell shape are observed. The RL-dependent association of increased ROS levels with cellular morphology was demonstrated by treating cells with a ROS-scavenging antioxidant which resulted in the observation of GL-characteristic rectangular morphology under RL. To gain additional insights into the involvement of ROS in impacting cellular morphology changes during CCA, we conducted experiments to study the temporal dynamics of changes in ROS levels and cellular morphology during transition to growth under RL or GL. Alterations in ROS levels and cell morphology were found to be correlated with each other at early stages of acclimation of low white light-grown cells to growth under high RL or cells transitioned between growth in RL and GL. These results provide further general evidence that significant RL-dependent increases in ROS levels are temporally correlated with changes in morphology toward spherical. Future studies will explore the light-dependent mechanisms by which ROS levels may be regulated and the direct impacts of ROS on the observed morphology changes.

Lumbosacral parasitic twin associated with lipomeningomyelocele: a rare occurrence.

Lumbosacral parasitic twin is an extremely rare entity. About 200 cases have been reported in the literature. It may be associated with neural tube defects. We encountered a 3-day-old female child with this presentation, who was successfully operated on at the age of about 2 months. Being an uncommon entity, it is presented here.

Biochemical alterations induced by acute oral doses of iron oxide nanoparticles in Wistar rats.

Magnetic iron oxide nanoparticles with appropriate surface chemistry have been widely used with potential new applications in biomedical industry. Therefore, the aim of this study was to assess the size-, dose-, and time-dependent effects, after acute oral exposure to iron oxide-30 NP (Fe(2)O(3)-30), on various biochemical enzyme activities of clinical significances in a female Wistar rat model. Rats were exposed to three different doses (500, 1,000, and 2,000 mg/kg) of Fe(2)O(3)-30 and Fe(2)O(3)-Bulk along with control. Fe(2)O(3)-30 had no effect on growth, behavior, and nutritional performance of animals. Fe(2)O(3)-30 caused significant inhibition of acetylcholinestrase in red blood cells as well as in brains of treated rats. Further, more than 50% inhibition of total, Na(+)-K(+), Mg(2+), and Ca(2+)-ATPases activities, as observed in brains of exposed female rats, may be the result of disturbances in cellular physiology and the iono-regulatory process. Activation of the hepatotoxicity marker enzymes, aspartate aminotransferase and alanine aminotransferase, was recorded in serum and liver, whereas inhibition was observed in kidney. Similarly, enhancement of lactate dehydrogenase activity was observed in serum and liver; however, a decrease in enzyme levels was observed in kidneys of Fe(2)O(3)-30-treated rats. On the other hand, Fe(2)O(3)-Bulk did not depict any significant changes in these biochemical parameters, and alterations were near to control. Therefore, this study suggests that exposure to nanosize particles at acute doses may cause adverse changes in animal biochemical profiles. The use of the rat model signifies the correlation with the human system.

Photoautotrophic black-colored cyanobacterial soil crust biosynthesizes photoprotective compounds and is capable of using blue, green, and red wavelengths of light for its growth.

Several cyanobacteria can adjust their light-harvesting machinery in response to existing light signals in a process called chromatic acclimation (CA) which permits the utilization of available light resources for photosynthesis. CA involves alteration in the pigment composition of a major light-harvesting complex called phycobilisome (PBS) and allows some cyanobacteria to utilize green light (GL) to drive photosynthesis. However, cyanobacteria, in contrast with eukaryotic algae and higher plants, can not utilize blue light (BL) for photosynthesis due to their dependency on PBS. Here, we studied a black-colored soil crust that was composed of a single cyanobacterium identified and named Oscillatoria sp. Malviya-1 after phenotypic and phylogenetic analyses. The black-colored crust can absorb light from almost all parts of photosynthetically active radiation (400-700 nm) and ultraviolet radiation (280-400 nm) due to the presence of photosynthetic pigments and microbial sunscreens such as chlorophyll ɑ, carotenoids, phycoerythrin, phycocyanin, allophycocyanin, mycosporine-like amino acids, and scytonemin. Unlike other cyanobacteria, Oscillatoria sp. Malviya-1 can grow using GL, BL, and red light (RL) in addition to white light (WL) which was accompanied by the different colors of the mat under different light conditions. The presence of CA and sunscreens compounds can maximize the fitness of soil crust under a dynamic light environment, UVR, and desiccation. Detailed study of Oscillatoria sp. Malviya-1 will provide information on the mechanism of CA in cyanobacterial soil crust and its unique ability to use both GL and BL.