The transportome of the endophyte Serendipita indica in free life and symbiosis with Arabidopsis and its expression in moderate salinity

Serendipita indica is an endophytic root symbiont fungus that enhances the growth of various plants under different stress conditions, including salinity. Here, the functional characterization of two fungal Na⁺/H⁺ antiporters, SiNHA1 and SiNHX1 has been carried out to study their putative role in saline tolerance. Although their gene expression does not respond specifically to saline conditions, they could contribute, together with the previously characterized Na⁺ efflux systems SiENA1 and SiENA5, to relieve Na⁺ from the S. indica cytosol under this stressed condition. In parallel, an in-silico study has been carried out to define its complete transportome. To further investigate the repertoire of transporters expressed in free-living cells of S. indica and during plant infection under saline conditions, a comprehensive RNA-seq approach was taken. Interestingly, SiENA5 was the only gene significantly induced under free-living conditions in response to moderate salinity at all the tested time points, revealing that it is one of the main salt-responsive genes of S. indica. In addition, the symbiosis with Arabidopsis thaliana also induced SiENA5 gene expression, but significant changes were only detected after long periods of infection, indicating that the association with the plant somehow buffers and protects the fungus against the external stress. Moreover, the significant and strongest induction of the homologous gene SiENA1 occurred during symbiosis, regardless the exposure to salinity. The obtained results suggest a novel and relevant role of these two proteins during the establishment and maintenance of fungus-plant interaction.

Concurrent Presentation of Mycosis Fungoides and Primary Cutaneous Marginal Zone LPD: Clinicopathological Study of 4 Cases and Literature Review

BACKGROUND

Mycosis fungoides is rarely associated to B-cell malignancies, and the few reported cases are mainly internal lymphomas involving secondarily the skin (ie, chronic lymphocytic leukemia).

OBJECTIVES

The aim of our study is to describe the clinical and histopathological features of 4 patients presenting with 2 concurrent primary cutaneous lymphomas and review the pertinent literature.

METHODS

We identified 4 cases of concurrent primary cutaneous lymphomas in our institutions. An extracutaneous lymphoma was ruled out on the basis of a complete work out. We performed a PubMed search to identify reported cases of primary cutaneous composite or concurrent lymphomas.

RESULTS

Eleven cases of primary cutaneous concurrent lymphomas have been described in the literature. Counting all together (our cases and the cases previously described in the literature), mycosis fungoides was the most frequent primary cutaneous T-cell lymphoma (TCL) (13/15), followed by 1 case of peripheral TCL-NOS and 1 case of subcutaneous panniculitis-like TCL. Regarding the associated primary cutaneous B-cell lymphomas, 8/15 cases consisted of low-grade B-cell lymphomas [that is, 5 marginal zone lymphoma (in the most recent classification reclassified as marginal zone lymphoproliferative disorder, MZLD, 2 follicular-center B-cell lymphoma (primary cutaneous follicle-center lymphoma) and 1 low-grade NOS B-cell lymphoma]; 4/15 were associated to Epstein-Barr virus; 1 case consisted of a methotrexate-associated lymphoproliferative disease, and 2 cases consisted of primary cutaneous diffuse large B-cell lymphoma-leg type.

CONCLUSIONS

Primary cutaneous concurrent lymphomas are exceptional. Clinicopathological correlation and a complete workout to reach the correct diagnosis may guide the appropriate treatment in each case.

K+ Nutrition Exchange in the Serendipita-Arabidopsis Symbiosis: Study of the Fungal K+ Transporters Involved

There is mounting evidence that the root-colonizing endosymbiotic fungus Serendipita indica improves plant growth. The beneficial effects have been observed when plants are growing in optimal conditions or under nutritionally deficient soils (e.g., phosphate poor soil) or exposed to stressful environmental conditions such as drought or salinity. However, until now its role in the nutrition of other plant essential macronutrient, such as K+, has not been fully clarified. Here, we study the role of the fungus in the K+ nutrition of Arabidopsis thaliana plants, during growth under K+ limiting conditions. As a first step, we studied the high-affinity K+ uptake of the plant and fungus when growing separately and in symbiosis. In the search for putative fungal actors involved in K+ nutrition, we also have cloned and functionally characterized the K+ transporters of S. indica SiHAK1, SiTRK1, SiTRK2, and SiTOK1, among which it has been shown that SiHAK1 is the main transporter involved in the K+ uptake in the high affinity range of concentrations. In addition, a gene expression study of these transporters and other candidates that could participate in the K+ homeostasis of the fungus has been carried out. The results indicated that, contrary to what happens with P nutrition, S. indica seems not to improve neither the growth nor the plant K+ reserves during K+ starvation. Instead, this nutritionally restrictive condition favored fungal colonization, suggesting that the fungus obtains the greatest benefit in K+ supply during symbiosis.

Subcutaneous panniculitis-like T-cell lymphoma, lupus erythematosus profundus, and overlapping cases: molecular characterization through the study of 208 genes

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic cutaneous lymphoma. Differential diagnosis with lupus erythematosus panniculitis (LEP) can be challenging and overlapping cases have been described. In this study, we investigate whether gene expression profiling may or not identify markers that can be used to improve our understanding of the disease and to make a precise differential diagnosis. SPTCL, LEP, and overlapping cases were analyzed using a customized NanoString platform including 208 genes related to T-cell differentiation, stromal signatures, oncogenes, and tumor suppressor genes. Gene expression unsupervised analysis of the samples differentiated SPTCL from LEP samples. Most overlapping cases were clustered with LEP cases. Differentially expressed genes were observed when comparing SPTCL with LEP cases; and overlapping with LEP cases. Gene set enrichment analysis recognized gene sets defining each group. In conclusion, SPTCL and LEP have distinctive molecular profiles and the molecular background of overlapping cases more closely resembles LEP.

Acral lymphomatoid papulosis: Report of five cases, differential diagnosis, and review

Acral lymphomatoid papulosis (a-LyP) is a rare clinical variant of LyP whose diagnosis may be challenging. A case series of a-LyP was studied clinically, histopathologically, immunohistochemically, and from molecular point of view. Including ours, 25 cases of a-LyP have so far been reported. Clinically, a-LyP may present as acral involvement exclusively, in combination with mucosal lesions, (in itself a rare presentation), or in association with conventional LyP. The age of presentation was slightly higher than that of conventional LyP (55 vs 45 years) and a male predominance has been observed, as usually reported. Histopathologically, no morphological differences exclusively from conventional LyP were observed. LyP types A and E were the main variants. We describe for the first time one case of type D a-LyP. Acral LyP is a rare entity and correct diagnosis can only be reached with clinical and histopathological correlation, to avoid aggressive treatment of this indolent lymphoproliferative disorder.

The endophyte Serendipita indica reduces the sodium content of Arabidopsis plants exposed to salt stress: fungal ENA ATPases are expressed and regulated at high pH and during plant co-cultivation in salinity

Serendipita indica (formerly Piriformospora indica) is an endophytic fungus that colonizes plant roots producing a beneficial effect on plant growth and development under optimal and suboptimal conditions provoked by any biotic or abiotic stress, such as salt stress. Salinity induces osmotic and ionic imbalances in plants, mainly by altering the Na⁺ and K⁺ contents. However, the mechanism by which Serendipita improves plant growth has yet to be elucidated. Previous works suggest that this fungus improves the plant osmotic state but not much is known about whether it participates in readjustment of the ionic imbalance in plants. Here, we report that co-cultivation with Serendipita reduces the Na⁺ content of Arabidopsis plants under saline conditions. Additionally, we describe the functional characterization of the two Serendipita ENA ATPases, which are homologous to the main proteins involved in the salt tolerance of other fungi. Their heterologous expression in salt-sensitive yeast mutants shows that SiENA1 is involved in Na⁺ and K⁺ efflux, while SiENA5 seems to only be involved in Na⁺ detoxification. Both are induced and might have a relevant function at alkaline pH, condition in which there are few chlamydospores in the mycelium, as well as during co-cultivation with plants exposed to saline conditions.

The Role of Soil Fungi in K+ Plant Nutrition

K⁺ is an essential cation and the most abundant in plant cells. After N, its corresponding element, K, is the nutrient required in the largest amounts by plants. Despite the numerous roles of K in crop production, improvements in the uptake and efficiency of use of K have not been major focuses in conventional or transgenic breeding studies in the past. In research on the mineral nutrition of plants in general, and K in particular, this nutrient has been shown to be essential to soil-dwelling-microorganisms (fungi, bacteria, protozoa, nematodes, etc.) that form mutualistic associations and that can influence the availability of mineral nutrients for plants. Therefore, this article aims to provide an overview of the role of soil microorganisms in supplying K⁺ to plants, considering both the potassium-solubilizing microorganisms and the potassium-facilitating microorganisms that are in close contact with the roots of plants. These microorganisms can influence the active transporter-mediated transfer of K⁺. Regarding the latter group of microorganisms, special focus is placed on the role of endophytic fungus. This review also includes a discussion on productivity through sustainable agriculture.

Regional lymphomatoid papulosis of the breast restricted to an area of prior radiotherapy

We report the case of a 59-year-old woman with type A regional lymphomatoid papulosis (LyP) that was localized to the left breast, a cutaneous area that had received radiotherapy for treatment of a carcinoma of the breast 5 years prior. This report is a rare example of regional LyP with all lesions located in an area of prior radiotherapy.

Salt intolerance in Arabidopsis: shoot and root sodium toxicity, and inhibition by sodium-plus-potassium overaccumulation

Arabidopsis plants in NaCl suffering half growth inhibition do not suffer osmotic stress and seldom shoot Na (+) toxicity; overaccumulation of Na (+) plus K (+) might trigger the inhibition. It is widely assumed that salinity inhibits plant growth by osmotic stress and shoot Na(+) toxicity. This study aims to examine the growth inhibition of Arabidopsis thaliana by NaCl concentrations that allow the completion of the life cycle. Unaffected Col-0 wild-type plants were used to define nontoxic Na(+) contents; Na(+) toxicities in shoots and roots were analyzed in hkt1 and sos1 mutants, respectively. The growth inhibition of Col-0 plants at 40 mM Na(+) was mild and equivalent to that produced by 8 and 4 mM Na(+) in hkt1 and sos1 plants, respectively. Therefore, these mutants allowed to study the toxicity of Na(+) in the absence of an osmotic challenge. Col-0 and Ts-1 accessions showed very different Na(+) contents but similar growth inhibitions; Ts-1 plants showed very high leaf Na(+) contents but no symptoms of Na(+) toxicity. Ak-1, C24, and Fei-0 plants were highly affected by NaCl showing evident symptoms of shoot Na(+) toxicity. Increasing K(+) in isotonic NaCl/KCl combinations dramatically decreased the Na(+) content in all Arabidopsis accessions and eliminated the signs of Na(+) toxicity in most of them but did not relieve growth inhibition. This suggested that the dominant inhibition in these conditions was either osmotic or of an ionic nature unspecific for Na(+) or K(+). Col-0 and Ts-1 plants growing in sorbitol showed a clear osmotic stress characterized by a notable decrease of their water content, but this response did not occur in NaCl. Overaccumulation of Na(+) plus K(+) might trigger growth reduction in NaCl-treated plants.

Amyophatic dermatomyositis presenting as a flagellated skin eruption with positive MDA5 antibodies and thyroid cancer: a real association?

Amyopathic dermatomyositis (ADM) is characterized clinically by typical skin lesions with hypomyopathy or no muscular involvement. ADM has been recently reported to be complicated by rapidly progressive interstitial lung disease (ILD), especially in patients with positive antibodies against melanoma differentiation-associated gene 5 (MDA5). These patients may have a low risk of cancer, but no clinical, histological or laboratory markers completely specific for paraneoplastic DM have been identified to date. We report a case of flagellate erythema as the initial presentation of ADM associated with ILD, positive MDA5 antibodies and a concomitant diagnosis of thyroid cancer. We discuss the unusual clinical features and associations that make this case particularly interesting.

The twins K+ and Na+ in plants

In the earth's crust and in seawater, K(+) and Na(+) are by far the most available monovalent inorganic cations. Physico-chemically, K(+) and Na(+) are very similar, but K(+) is widely used by plants whereas Na(+) can easily reach toxic levels. Indeed, salinity is one of the major and growing threats to agricultural production. In this article, we outline the fundamental bases for the differences between Na(+) and K(+). We present the foundation of transporter selectivity and summarize findings on transporters of the HKT type, which are reported to transport Na(+) and/or Na(+) and K(+), and may play a central role in Na(+) utilization and detoxification in plants. Based on the structural differences in the hydration shells of K(+) and Na(+), and by comparison with sodium channels, we present an ad hoc mechanistic model that can account for ion permeation through HKTs.

The potassium transporters HAK2 and HAK3 localize to endomembranes in Physcomitrella patens. HAK2 is required in some stress conditions

The function of HAK transporters in high-affinity K+ uptake in plants is well established; this study aims to demonstrate that some transporters of the same family play important roles in endomembranes. The PpHAK2-PpHAK4 genes of Physcomitrella patens encode three transporters of high sequence similarity. Quantitative PCR showed that PpHAK2 and PpHAK3 transcripts are expressed at approximately the same level as the PpACT5 gene, while the expression of PpHAK4 seems to be restricted to specific conditions that have not been determined. KHA1 is an endomembrane K+/H+ antiporter of Saccharomyces cerevisiae, and the expression of the PpHAK2 cDNA, but not that of PpHAK3, suppressed the defect of a kha1 mutant. Transient expression of the PpHAK2-green fluorescent protein (GFP) and PpHAK3-GFP fusion proteins in P. patens protoplasts localized to the endoplasmic reticulum and Golgi complex, respectively. To determine the function of PpHAK2 and PpHAK3 in planta, we constructed ΔPphak2 and ΔPphak2 ΔPphak3 plants. ΔPphak2 plants were normal under all of the conditions tested except under K+ starvation or at acidic pH in the presence of acetic acid, whereupon they die. The defect observed under K+ starvation was suppressed by the presence of Na+. We propose that PpHAK2 may encode either a K(+)-H(+) symporter or a K+/H+ antiporter that mediates the transfer of H+ from the endoplasmic reticulum lumen to the cytosol. PpHAK2 may be a model of the second function of HAK transporters in plant cells. The disruption of the PpHAK3 gene in ΔPphak2 plants showed no effect.

Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+ /K+ homeostasis

The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na(+) ] and [K(+) ] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na(+) -selective class I-HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single-nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near-isogenic lines (NILs): 157-14 (double homozygote for the cheesmaniae alleles) and 157-17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157-14 in comparison with 157-17. A significant difference between NILs was also found for [K(+) ] and the [Na(+) ]/[K(+) ] ratio in leaf and stem but not for [Na(+) ] arising a disagreement with the corresponding RIL population. Their association with leaf [Na(+) ] and salt tolerance in tomato is also discussed.

Phylogenetic analysis of k(+) transporters in bryophytes, lycophytes, and flowering plants indicates a specialization of vascular plants

As heritage from early evolution, potassium (K(+)) is absolutely necessary for all living cells. It plays significant roles as stabilizer in metabolism and is important for enzyme activation, stabilization of protein synthesis, and neutralization of negative charges on cellular molecules as proteins and nucleic acids. Land plants even enlarged this spectrum of K(+) utilization after having gone ashore, despite the fact that K(+) is far less available in their new oligotrophic habitats than in sea water. Inevitably, plant cells had to improve and to develop unique transport systems for K(+) accumulation and distribution. In the past two decades a manifold of K(+) transporters from flowering plants has been identified at the molecular level. The recently published genome of the fern ally Selaginella moellendorffii now helps in providing a better understanding on the molecular changes involved in the colonization of land and the development of the vasculature and the seeds. In this article we present an inventory of K(+) transporters of this lycophyte and pigeonhole them together with their relatives from the moss Physcomitrella patens, the monocotyledon Oryza sativa, and two dicotyledonous species, the herbaceous plant Arabidopsis thaliana, and the tree Populus trichocarpa. Interestingly, the transition of green plants from an aqueous to a dry environment coincides with a dramatic reduction in the diversity of voltage-gated potassium channels followed by a diversification on the basis of one surviving K(+) channel class. The first appearance of K(+) release (K(out)) channels in S. moellendorffii that were shown in Arabidopsis to be involved in xylem loading and guard cell closure coincides with the specialization of vascular plants and may indicate an important adaptive step.

Diffuse lower limb lipoatrophy

Lipoatrophic panniculitis is the term used to describe those panniculitides in which atrophy of the subcutaneous fat is the main residual lesion. They can be classified as primary or secondary. Primary lipoatrophic panniculitis is idiopathic, whereas secondary lipoatrophic panniculitides include those because of infection, malignancy, pancreatic disorders or connective tissue diseases. Usually, these entities are characterized by the appearance of tender, erythematous nodules or plaques that resolve leaving one or several localized areas with loss of subcutaneous fat. We report a 76-year-old female who developed diffuse and symmetric lipoatrophy of lower limbs after an extensive inflammatory process affecting both extremities from thighs to ankles. Histopathologic assessment revealed a lobular panniculitis with a lymphohistiocytic infiltrate, foamy macrophages and lipophagic granuloma formation. The most striking feature in our patient was the clinical presentation as a symmetrical diffuse inflammatory process resulting in lipoatrophy of the lower limbs.

High-affinity sodium uptake in land plants

High-affinity Na(+) uptake in plants and its mediation by HKT transporters have been studied in very few species. This study expands the knowledge of high-affinity Na(+) uptake in land plants for both uptake characteristics and involvement of HKT transporters. In non-flowering plants, we analyzed the Na(+) content of wild mosses, carried out experiments on K(+) and Na(+) uptake in the micromolar range of concentrations with the moss Physcomitrella patens and the liverwort Riccia fluitans, studied a Deltahkt1 mutant of P. patens and identified the HKT genes of the lycopodiophyta (clubmoss) Selaginella moellendorffii. In flowering plants we studied Na(+) uptake in the micromolar range of concentrations in 16 crop plant species, identified the HKT transporters that could mediate high-affinity Na(+) uptake in several species of the Triticeae tribe, and described some characteristics of high-affinity Na(+) uptake in other species. Our results suggest that high-affinity Na(+) uptake occurs in most land plants. In very few of them, rice and species in the Triticeae and Aveneae tribes of the Poaceae family, it is probably mediated by HKT transporters. In other plants, high-affinity Na(+) uptake is mediated by one or several transporters whose responses to the presence of K(+) or Ba(2+) are fundamentally different from those of HKT transporters.

Plaque-like osteoma cutis with transepidermal elimination

Osteoma cutis is a rare lesion that consists of the presence of bone tissue within the dermis and/or hypodermis. It may be classified as primary osteoma cutis, when bone tissue develops in the skin without any pre-existing lesion and secondary osteoma cutis, which is more frequent and occurs when osseous tissue develops on a pre-existing lesion. We present a case of primary plaque-like osteoma cutis involving the scalp, left forehead and left cheek, which appeared in an adult male. Histopathological study showed several islands of mature osseous tissue involving the full thickness of the dermis. In some areas, there was also transepidermal elimination of bone spicules. We review the literature about previously reported similar cases.

[Proliferative cutaneous epithelioid angiomatous nodule]

The cutaneous epithelioid angiomatous nodule is an uncommon benign vascular proliferation that has only recently been described. Clinically, it usually presents as a solitary, fast-growing, small reddish papulous or nodular lesion on the trunk or limbs of adults. Histopathologic study reveals a proliferation of epithelioid cells and predominantly solid, well delimited, unilobular growth in the superficial dermis. Well defined vessels are often found permeating the lesion, which also shows a certain degree of inflammatory infiltration. The cells contain abundant pink cytoplasm, often with vacuoles, and vesicular nuclei with prominent nucleoli. The morphology of these cells is relatively uniform, without atypia or pleomorphism, although mitoses are not uncommon. We report 2 new cases of cutaneous epithelioid angiomatous nodules, the first in a 28-year-old pregnant woman and the second in a 27-year-old man. In both cases, the usual characteristics of this entity were present, but with the peculiarity of a high mitotic index. We discuss the differential diagnosis of cutaneous epithelioid angiomatous nodules with other vascular proliferations that exhibit epithelioid cytology.

[Trichilemmal horn: a new case and review of the literature]

Trichilemmal horn, or trichilemmal keratosis, is an uncommon benign neoplasm of follicular lineage with trichilemmal differentiation. The essential characteristics of this tumor are its clinical presentation in the form of a cutaneous horn with trichilemmal keratinization apparent in the histology study (with a hyperplastic epithelium giving rise to dense, orthokeratotic eosinophilic keratin). We present a new case of this type of tumor in an 82-year-old woman who developed a solitary lesion on her scalp after surgical removal of a trichilemmal cyst. On the basis of the pathology report, the tumor was diagnosed as trichilemmal horn. We review the 33 reports of this tumor in the literature to date.

Effects of polylinker uATGs on the function of grass HKT1 transporters expressed in yeast cells

HvHKT1 mediates K(+) or Na(+) uniport in yeast cells if the expression promoter is joined directly to the HvHKT1 cDNA, and Na(+)-K(+) symport if a 59 nucleotide polylinker is inserted. Our results show that three ATG triplets in the polylinker decreased the synthesis of the transporter and that the lower amount of transporter caused the functional change. With the rice HKT1 cDNA, the 59 nt polylinker changed the mode of Na(+) uptake from K(+)-insensitive to K(+)-inhibitable. These two modes of Na(+) uptake also occurred in rice plants.

Late-onset Ito?s nevus: An uncommon acquired dermal melanocytosis

Dermal melanocytoses comprise a variety of congenital and acquired conditions characterized by a sparse population of intradermal dendritic, variably pigmented, spindle-shaped melanocytes. While Mongolian spot, Ota's and Ito's nevi are usually present at birth or appear around puberty; acquired dermal melanocytoses that appear in adult life are extremely rare. They include the facial lesions of acquired bilateral nevus of Ota-like macules, also named Hori's nevus, and the acquired unilateral nevus of Ota, also known as Sun's nevus. Uncommon extrafacial examples of acquired dermal melanocytoses include lesions involving upper extremities, wrist, back, lower extremities and dorsal aspects of the hands and feet. They are more prevalent among Asian women. In general, dermal melanocytoses are rare lesions in Caucasian patients and acquired variants are exceedingly uncommon. We report a rare example of acquired Ito's nevus that appeared in a Caucasian elderly woman and review the literature about acquired dermal melanocytoses.

Cloning of two SOS1 transporters from the seagrass Cymodocea nodosa. SOS1 transporters from Cymodocea and Arabidopsis mediate potassium uptake in bacteria

Two cDNAs isolated from Cymodocea nodosa, CnSOS1A, and CnSOSIB encode proteins with high-sequence similarities to SOS1 plant transporters. CnSOS1A expressed in a yeast Na+-efflux mutant under the control of a constitutive expression promoter mimicked AtSOS1 from Arabidopsis; the wild type cDNA did not improve the growth of the recipient strain in the presence of Na+, but a cDNA mutant that expresses a truncated protein suppressed the defect of the yeast mutant. In similar experiments, CnSOS1B was not effective. Conditional expression, under the control of an arabinose responsive promoter, of the CnSOSIA and CnSOS1B cDNAs in an Escherichia coli mutant defective in Na+ efflux was toxic, and functional analyses were inconclusive. The same constructs transformed into an E. coli K+-uptake mutant revealed that CnSOS1A was also toxic, but that it slightly suppressed defective growth at low K+. Truncation in the C-terminal hydrophilic tail of CnSOS1A relieved the toxicity and proved that CnSOS1A was an excellent low-affinity K+ and Rb+ transporter. CnSOS1B mediated a transient, extremely rapid K+ or Rb+ influx. Similar tests with AtSOS1 revealed that it was not toxic and that the whole protein exhibited excellent K+ and Rb+ uptake characteristics in bacteria.

HKT1 mediates sodium uniport in roots. Pitfalls in the expression of HKT1 in yeast

The function of HKT1 in roots is controversial. We tackled this controversy by studying Na+ uptake in barley (Hordeum vulgare) roots, cloning the HvHKT1 gene, and expressing the HvHKT1 cDNA in yeast (Saccharomyces cerevisiae) cells. High-affinity Na+ uptake was not detected in plants growing at high K+ but appeared soon after exposing the plants to a K(+)-free medium. It was a uniport, insensitive to external K+ at the beginning of K+ starvation and inhibitable by K+ several hours later. The expression of HvHKT1 in yeast was Na+ (or K+) uniport, Na(+)-K+ symport, or a mix of both, depending on the construct from which the transporter was expressed. The Na+ uniport function was insensitive to external K+ and mimicked the Na+ uptake carried out by the roots at the beginning of K+ starvation. The K+ uniport function only took place in yeast cells that were completely K+ starved and disappeared when internal K+ increased, which makes it unlikely that HvHKT1 mediates K+ uptake in roots. Mutation of the first in-frame AUG codon of HvHKT1 to CUC changed the uniport function into symport. The expression of the symport from either mutants or constructs keeping the first in-frame AUG took place only in K(+)-starved cells, while the uniport was expressed in all conditions. We discuss here that the symport occurs only in heterologous expression. It is most likely related to the K+ inhibitable Na+ uptake process of roots that heterologous systems fail to reproduce.

A Two-Year Study on the Effects of Nicotine and its Withdrawal on Mood and Sleep

Acute administration of nicotine has beneficial effects on a variety of neurological and psychiatric disorders. The purpose of this study was to determine the long-term effects of transdermal nicotine on sleep and major depression. Under a single blind protocol study where patients initially received nicotine and then switched to placebo. Fourteen non-smoking patients with major depression (Hamilton Rating > or = 18) served as subjects. Transdermal nicotine (17.5 mg), was administered five days weekly for six months, three days weekly on month 7 and one day per week on month 8. From the 9th to the 24th month, once a week a patch without nicotine substituted the nicotine patch. Sleep and depression was assessed throughout. REM sleep latency changed from 32.6 min. to 78.2 min. at the end of the study, wakefulness decreased, slow wave sleep increased throughout the study and a transient decrease of REM sleep duration upon nicotine withdrawal was observed. Hamilton scores went from an initial mean score of 29.7 to a final score of 10.8. The results support the possible therapeutical effects of long-term transdermal nicotine on sleep and mood, with a carryover effect into the withdrawal period, even though, the conclusions should be taken with caution due to the design applied.

Functional analysis of the M2(D) helix of the TRK1 potassium transporter of Saccharomyces cerevisiae

Eukaryotic KcsA-related K+ transporters mediate physiologically relevant K+ and Na+ fluxes in fungi and plants. ScTRK1 is a characteristic member of the group, and here we report a mutational analysis of the unique M2(D) helix of this transporter. Our results support the theoretical models placing this helix in a relevant position in the pore and interacting with P segments. Most single mutations eliminating positively charged or introducing negatively charged residues reduced the V(max) of Rb+ influx to a half, several together showed an additive effect, and four practically suppressed transport. In contrast, the introduction of only one positively charged residue practically abolished the function of the transporter. Almost all mutations in the M2(D) helix affected the two Rb+ binding sites of the transporter, mimicking mutations in the selectivity filter.

Molecular analysis of the mechanism of potassium uptake through the TRK1 transporter of Saccharomyces cerevisiae

The TRK-HKT family of K(+) transporters mediates K(+) and Na(+) uptake in fungi and plants. In this study, we have investigated the molecular mechanism involved in the movement of alkali cations through the TRK1 transporter of Saccharomyces cerevisiae. The model that best explains the activity of ScTRK1 is a cotransport of two K(+) or Rb(+), both of which bind the two binding sites of ScTRK1 with very high affinities in K(+)-starved cells. Na(+) can be transported in the same way but it exhibits a much lower affinity for the second binding site. Therefore, only at critical concentration ratios between K(+) and Na(+), or Rb(+) and Na(+), the transporter takes up Na(+) together with K(+) or Rb(+). Mutation analyses suggest that the two binding sites are located in the P fragment of the first MPM motif of the transporter, and that Gln(90) is involved in these binding sites. ScTRK1 can be in two states, medium or high affinity, and we have found that Leu(949) is involved in the oscillation of the transporter between these two states. ScTRK1 mediates active K(+) uptake. This is not Na(+)-coupled and direct coupling of ScTRK1 to a source of chemical energy seems more probable than K(+)-H(+) cotransport.

Cloning of two genes encoding potassium transporters in Neurospora crassa and expression of the corresponding cDNAs in Saccharomyces cerevisiae

Two Neurospora crassa genes, trk-1 and hak-1, encode K+ transporters that show sequence similarities to the TRK transporters described in Saccharomyces cerevisiae and Schizosaccharomyces pombe, and to the HAK transporters described in Schwanniomyces occidentalis and barley. The N. crassa TRK1 and HAK1 transporters expressed by the corresponding cDNAs in a trk1 delta trk2 delta mutant of S. cerevisiae exhibited a high affinity for Rb+ and K+. Northern blot analysis and comparison of the kinetic characteristics of the two transporters in the trk1 delta trk2 delta mutant with the kinetic characteristics of K+ uptake in N. crassa cells allowed TRK1 to be identified as the dominant K+ transporter and HAK1 as a transporter that is only expressed when the cells are K+ starved. The HAK1 transporter showed a high concentrative capacity and is identified as the K(+)-H+ symporter described in N. crassa, whereas TRK1 might be a K+ uniporter. Although the co-existence of K+ transporters of the TRK and HAK types in the same species had not been reported formerly, we discuss whether this co-existence may be the normal situation in soil fungi.

EEG interhemispheric correlation after callosotomy: one case study

High interhemispheric EEG correlation (INTERr) or coherence has been interpreted as a consequence of callosal interconnections. The EEG of a callosotomized (two anterior thirds) 32-yr.-old patient was recorded during relaxed wakefulness with eyes closed. 100 2-sec. artifact-free epochs were digitally filtered into traditional broad bands and INTERr was calculated by means of Pearson product-moment coefficients. INTERr between anterior regions, where they should be expected, showed very few differences between data of this patient and those of two control groups of healthy persons. Only a few differences were observed between posterior regions where the callosum was intact. These results suggest that the role of the callosum is not crucial for INTERr and that subcortical influences and functional differentiation between hemispheres may be more plausible explanations for INTERr.

TRK2 is not a low-affinity potassium transporter in Saccharomyces cerevisiae

TRK1 and TRK2 encode proteins involved in K+ uptake in Saccharomyces cerevisiae. A kinetic study of Rb+ influx in trk1 TRK2, trk1 TRK2D, and trk1 trk2 mutants reveals that TRK2 shows moderate affinity for Rb+. K(+)-starved trk1 delta TRK2 cells show a low-affinity component accounting for almost the total Vmax of the influx and a moderate-affinity component exhibiting a very low Vmax. Overexpression of TRK2 in trk1 delta TRK2D cells increases the Vmax of the moderate-affinity component, and this component disappears in trk1 delta trk2 delta cells. In contrast, the low-affinity component of Rb+ influx in trk1 delta TRK2 cells is not affected by mutations in TRK2. Consistent with the different levels of activity of the moderate-affinity Rb+ influx, trk1 delta TRK2 cells grow slowly in micromolar K+, trk1 delta TRK2D cells grow rapidly, and trk1 delta trk2 delta cells fail to grow. The existence of a unique K+ uptake system composed of several proteins is also discussed.

Effects of ozone exposure during pregnancy on ontogeny of sleep in rats

Few studies regarding the effects of ozone exposure in the central nervous system (CNS), during the early stages of development have been reported. The study of sleep on newborn rats represents a model to understand the effects of this gas on the CNS. We studied the sleep organization in rats whose mothers were exposed to 1 part per million (ppm) ozone during pregnancy. We found severe sleep disturbances such as a decrease in paradoxical sleep duration and inversion of the light-dark cycle or a circadian phase-shift of vigilance states. These results suggest that ozone exposure during pregnancy may affect the generating mechanisms of paradoxical sleep, and the regulation of circadian rhythms in rats.

Obstructive sleep apnea secondary to surgery for velopharyngeal insufficiency

The files of 585 patients who had had pharyngeal flap surgery for the correction of velopharyngeal insufficiency were reviewed. Eighteen patients, ranging in age from 6 to 16 years, showed clinical symptoms of obstructive sleep apnea syndrome. All of these cases had a polysomnographic evaluation and videonasopharyngoscopy. Fifteen cases met the criteria for the diagnosis of obstructive sleep apnea syndrome and eventually underwent surgical treatment. A modified uvulopalatopharyngoplasty was done in 14 of the 15 cases. One patient had a prominent uvula flipping into the port of a Jackson's type pharyngoplasty, so a partial resection of the uvula was performed. Surgical treatment was successful in 14 of 15 cases, including the case with the partial uvular resection. In one case, severe sleep apnea persisted after surgery and a complete section of the flap was performed to correct the obstruction. Sizeable tonsils were found in 13 out of 15 cases, whereas flap width appeared unrelated to obstruction. Preoperative assessment of tonsillar tissue is of vital importance before pharyngeal flap surgery.

Multiple sleep latency test (MSLT) and sleep apnea in aged women

Sleep disturbance and the tendency to sleep during the day were assessed polysomnographically in 31 elderly women (mean age = 76.7 +/- 3.6 SD) recruited from a senior citizen's living facility without reference to sleep-wake complaints. The data showed that the level of sleepiness during the day in each subject depended in part on the severity of her respiratory disturbance. It was found that the group (n = 7) of elderly females with apnea and hypopnea index (AHI) higher than 20 was more sleepy [multiple sleep latency test (MSLT) = 7.9 +/- 2) than the group (n = 10) with AHI > 5 but less than 20 (MSLT = 12.7 +/- 5). Nevertheless, the presence and severity of respiratory disturbance were not the only factors that influenced the level of sleepiness during the day in the studied sample. A subgroup of four elderly females showed a marked sleepiness during the four tested periods (MSLT = 5.2 +/- 0.6) with a very low respiratory disturbance index (AHI = 5.5 +/- 0.8).

Differential expression of two genes encoding isoforms of the ATPase involved in sodium efflux in Saccharomyces cerevisiae

The ENA2 gene encoding a P-type ATPase involved in Na+ and Li+ effluxes in Saccharomyces cerevisiae has been isolated. The putative protein encoded by ENA2 differs only in thirteen amino acids from the protein encoded by ENA1/PMR2. However, ENA2 has a very low level of expression and for this reason did not confer significant Li+ tolerance on a Li+ sensitive strain. ENA1 and ENA2 are the first two units of a tandem array of four highly homologous genes with probably homologous functions.

Activation of the potassium uptake system during fermentation in Saccharomyces cerevisiae

Fermentable sugars activated the K+ uptake system, increasing the Vmaxs of Rb+, Na+, and Li+ influxes, but sugars did not affect the effluxes of these cations. This activation seems to be a direct effect of fermentation and not the consequence of the H+ pump ATPase activation or internal pH decrease produced by fermentation.

A novel P-type ATPase from yeast involved in sodium transport

The gene ENA1 was cloned by its ability to complement the Li+ sensitivity of a low Li(+)-efflux strain. The nucleotide sequence of the cloned DNA fragment showed that there are two almost identical genes in tandem, and predicts that they encode P-ATPases. Disruption of both genes originated a strain defective in Na+ and Li+ effluxes, and sensitive to Na+, to Li+ and to alkaline pH. By transformation with ENA1 the defective effluxes and tolerances were repaired.

Regulation of potassium fluxes in Saccharomyces cerevisiae

To investigate the regulation of K+ fluxes in Saccharomyces cerevisiae the dependence of K+ efflux and Rb+ influx on [K+]i, pHi, [Na+]i, membrane potential, cell volume, and turgor pressure were studied in cells with different K+ contents. By decreasing the cell volume with osmotic shocks and the cellular pH with butyric acid the following was found. (1) The K+ efflux induced by uncouplers decreases simultaneously with the decrease of the K+ content of the cell, but the process was insensitive to [K+]i, pHi, cell volume and turgor pressure. The internal presence of Na+ inhibited this K+ efflux. (2) The increase of the Vmax of Rb+ influx observed in low-K+ cells is due to the decrease of the pHi and probably mediated by the increase of the activity of the plasma membrane ATPase. The Vmax is independent of [K+]i, [Na+]i, cell volume and turgor pressure. (3) The decrease in the Km of Bt+ influx observed in low-K+ cells does not depend directly on [K+]i, pHi, cell volume or turgor pressure. If Na+ is present, [Na+]i might be directly involved in the regulation of the Km.