Conjugated carbon monoxide-releasing molecules have broad-spectrum antimicrobial activity

Aim: To test the antimicrobial effect of carbon monoxide-releasing molecules (CORMs) conjugated with azoles on different microorganisms. Methods & results: We used broth microdilution, checkerboard and cytotoxicity assays, as well as imaging, fluorescence and bioluminescence experiments to study [Re(CO)3(2,2'-bipyridyl)(Ctz)]+ (also known as ReBpyCtz). ReBpyCtz exhibits a low minimum inhibitory concentration value, increases the intracellular formation of reactive oxygen species and causes significant alterations on Staphylococcus aureus's membrane. ReBpyCtz is active against fungi, having a more prolonged fungicidal effect on Candida glabrata than clotrimazole and is selectively active on blood-stage malaria parasites, at a concentration that is not toxic to kidney epithelial cells. Conclusion: Conjugated CORMs have the potential to be active against different types of pathogens, thus constituting a promising class of broad-spectrum antimicrobials.

Antifungal Potential of Marine Organisms of the Yucatan Peninsula (Mexico) against Medically Important Candida spp

Invasive fungal infections represent a global health threat. They are associated with high mortality and morbidity rates, partly due to the ineffectiveness of the available antifungal agents. The rampant increase in infections recalcitrant to the current antifungals has worsened this scenario and made the discovery of new and more effective antifungals a pressing health issue. In this study, 65 extracts from marine organisms of the Yucatan Peninsula, Mexico, were screened for antifungal activity against Candida albicans and Candida glabrata, two of the most prevalent fungal species that cause nosocomial invasive fungal infections worldwide. A total of 51 sponges, 13 ascidians and 1 gorgonian were collected from the coral reef and mangrove forest in the Yucatan Peninsula (Mexico) and extracted with organic solvents. Nine crude extracts showed potent antifungal activity, of which four extracts from the sponge species Aiolochroia crassa, Amphimedon compressa, Monanchora arbuscula and Agelas citrina had promising activity against Candida spp. Bioassay-guided fractionation of the M. arbuscula extract revealed the remarkable fungicidal activity of some fractions. Analysis of the chemical composition of one of the most active fractions by UHPLC-HRMS and NMR indicated the presence of mirabilin B and penaresidin B, and their contribution to the observed antifungal activity is discussed. Overall, this work highlights marine organisms of the Yucatan Peninsula as important reservoirs of natural products with promising fungicidal activity, which may greatly advance the treatment of invasive fungal infections, especially those afflicting immunosuppressed patients.

Copper Acts Synergistically With Fluconazole in Candida glabrata by Compromising Drug Efflux, Sterol Metabolism, and Zinc Homeostasis

The synergistic combinations of drugs are promising strategies to boost the effectiveness of current antifungals and thus prevent the emergence of resistance. In this work, we show that copper and the antifungal fluconazole act synergistically against Candida glabrata, an opportunistic pathogenic yeast intrinsically tolerant to fluconazole. Analyses of the transcriptomic profile of C. glabrata after the combination of copper and fluconazole showed that the expression of the multidrug transporter gene CDR1 was decreased, suggesting that fluconazole efflux could be affected. In agreement, we observed that copper inhibits the transactivation of Pdr1, the transcription regulator of multidrug transporters and leads to the intracellular accumulation of fluconazole. Copper also decreases the transcriptional induction of ergosterol biosynthesis (ERG) genes by fluconazole, which culminates in the accumulation of toxic sterols. Co-treatment of cells with copper and fluconazole should affect the function of proteins located in the plasma membrane, as several ultrastructural alterations, including irregular cell wall and plasma membrane and loss of cell wall integrity, were observed. Finally, we show that the combination of copper and fluconazole downregulates the expression of the gene encoding the zinc-responsive transcription regulator Zap1, which possibly, together with the membrane transporters malfunction, generates zinc depletion. Supplementation with zinc reverts the toxic effect of combining copper with fluconazole, underscoring the importance of this metal in the observed synergistic effect. Overall, this work, while unveiling the molecular basis that supports the use of copper to enhance the effectiveness of fluconazole, paves the way for the development of new metal-based antifungal strategies.

Zap1 is required for Candida glabrata response to fluconazole

The increasing prevalence of fluconazole-resistant clinical isolates of Candida spp. strongly hinders the widespread use of the drug. To tackle this problem, great efforts have been made to fully understand the fungal response to fluconazole. In this work, we show that the role of Zap1 in Candida glabrata goes beyond regulating yeast adaptation to zinc deficiency. In line with our previous observation that deletion of ZAP1 makes yeast cells more sensitive to fluconazole, we found that the mutant CgΔzap1 accumulates higher levels of the drug, which correlates well with its lower levels of ergosterol. Surprisingly, Zap1 is a negative regulator of the drug efflux transporter gene CDR1 and of its regulator, PDR1. The apparent paradox of drug accumulation in cells where genes encoding transporters relevant for drug extrusion are being overexpressed led us to postulate that their activity could be impaired. In agreement, Zap1-depleted cells present, in addition to decreased ergosterol levels, an altered composition of membrane phospholipids, which together should impact membrane function and impair the detoxification of fluconazole. Overall, our study brings to light Zap1 as an important hub in Candida glabrata response to fluconazole.

A molecular test based on RT-LAMP for rapid, sensitive and inexpensive colorimetric detection of SARS-CoV-2 in clinical samples

Until there is an effective implementation of COVID-19 vaccination program, a robust testing strategy, along with prevention measures, will continue to be the most viable way to control disease spread. Such a strategy should rely on disparate diagnostic tests to prevent a slowdown in testing due to lack of materials and reagents imposed by supply chain problems, which happened at the beginning of the pandemic. In this study, we have established a single-tube test based on RT-LAMP that enables the visual detection of less than 100 viral genome copies of SARS-CoV-2 within 30 min. We benchmarked the assay against the gold standard test for COVID-19 diagnosis, RT-PCR, using 177 nasopharyngeal RNA samples. For viral loads above 100 copies, the RT-LAMP assay had a sensitivity of 100% and a specificity of 96.1%. Additionally, we set up a RNA extraction-free RT-LAMP test capable of detecting SARS-CoV-2 directly from saliva samples, albeit with lower sensitivity. The saliva was self-collected and the collection tube remained closed until inactivation, thereby ensuring the protection of the testing personnel. As expected, RNA extraction from saliva samples increased the sensitivity of the test. To lower the costs associated with RNA extraction, we performed this step using an alternative protocol that uses plasmid DNA extraction columns. We also produced the enzymes needed for the assay and established an in-house-made RT-LAMP test independent of specific distribution channels. Finally, we developed a new colorimetric method that allowed the detection of LAMP products by the visualization of an evident color shift, regardless of the reaction pH.

Granulosa cells provide elimination of apoptotic oocytes through unconventional autophagy-assisted phagocytosis

STUDY QUESTION

Do human granulosa cells (GCs) ingest and destroy apoptotic oocytes?

SUMMARY ANSWER

Somatic GCs ingest and destroy apoptotic oocytes and other apoptotic substrates through unconventional autophagy-assisted phagocytosis.

WHAT IS KNOWN ALREADY

Most (99%) ovarian germ cells undergo apoptosis through follicular atresia. The mode of cleaning of atretic follicles from the ovary is unclear. Ovarian GCs share striking similarities with testicular Sertoli cells with respect to their origin and function. Somatic Sertoli cells are responsible for the elimination of apoptotic spermatogenic cells through unconventional autophagy-assisted phagocytosis.

STUDY DESIGN, SIZE, DURATION

Human GCs were tested for the ability to ingest and destroy the apoptotic oocytes and other apoptotic substrates. A systemic study of the main phagocytosis steps has been performed at different time points after loading of apoptotic substrates into the GC.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Primary cultures of GC retrieved following controlled ovarian stimulation of five women for IVF/ICSI and a human granulosa KGN cell line were incubated with different apoptotic substrates: oocytes which underwent spontaneous apoptosis during the cultivation of immature germ cells for IVF/ICSI; apoptotic KGN cells; and apoptotic membranes from rat retinas. Cultured GC were analyzed for the presence of specific molecular markers characteristic of different steps of phagocytic and autophagy machineries by immunocytochemistry, confocal microscopy, transmission electron microscopy and western blotting, before and after loading with apoptotic substrates.

MAIN RESULTS AND THE ROLE OF CHANCE

Incubation of human GC with apoptotic substrates resulted in their translocation in cell cytoplasm, concomitant with activation of the phagocytosis receptor c-mer proto-oncogene tyrosine kinase MERTK (P < 0.001), clumping of motor molecule myosin II, recruitment of autophagy proteins: autophagy-related protein 5 (ATG5), autophagy-related protein 6 (Beclin1) and the rise of a membrane form of microtubule-associated protein 1 light chain 3 (LC3-II) protein. Ingestion of apoptotic substrates was accompanied by increased expression of the lysosomal protease Cathepsin D (P < 0.001), and a rise of lysosomes in the GCs, as assessed by different techniques. The level of autophagy adaptor, sequestosome 1/p62 (p62) protein remained unchanged.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The number of patients described here is limited. Also the dependence of phagocytosis on reproductive hormone status of patients should be analyzed.

WIDER IMPLICATIONS OF THE FINDINGS

Removal of apoptotic oocytes by surrounding GC seems likely to be a physiological mechanism involved in follicular atresia. Proper functioning of this mechanism may be a new strategy for the treatment of ovarian dysfunctions associated with an imbalance in content of germ cells in the ovaries, such as premature ovarian failure and polycystic ovary syndrome.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by Rennes Metropole (AIS 2015) and Agence de BioMédecine. This work was supported by funding from Université de Rennes1, Institut National de la Santé et de la Recherche Médicale (INSERM) and CHU de Rennes. A.B. is funded in part by the program Actions Concertées Interpasteuriennes (ACIP) and a research grant from the European Society of Pediatric Endocrinology. This work is supported by the Agence Nationale de la Recherche Grants ANR-17-CE14-0038 and ANR-10-LABX-73. The authors declare no competing interests.

Toward alternative sources of milk coagulants for cheese manufacturing: establishment of hairy roots culture and protease characterization from Cynara cardunculus L

Extracts from hairy root cultures of Cynara cardunculus L. contain proteases and show milk-clotting activity. Cynara cardunculus L. or cardoon is often used as rennet in traditional cheese manufacturing, due to the presence of specific proteases in the flower. However, the flower extracts are variable depending on the provenance and quality of the flowers as well as high genetic variability among cardoon populations, and this affects the quality of the final product. In search for alternative sources of milk-clotting enzymes, hairy root cultures from cardoon were obtained and characterized regarding their protease content and proteolytic activity toward milk proteins. Aspartic, serine and cysteine proteases were identified in hairy roots by mass spectrometry analysis and an azocasein assay combined with specific inhibitors. RT-PCR analysis revealed the expression of cardosin A and D, and immunoblotting analysis suggested the presence of cardosin A or cardosin A-like enzyme in its mature form, supporting this system as an alternative source of cardosins. Hairy root protein extracts showed activity over caseins, supporting its use as milk coagulant, which was further tested by milk-clotting assays. This is also the first report on the establishment of hairy root cultures from cardoon, which paves the way for future work on controlled platforms for production of valuable metabolites which are known to be present in this species.

Yeast AP-1 like transcription factors (Yap) and stress response: a current overview

Yeast adaptation to stress has been extensively studied. It involves large reprogramming of genome expression operated by many, more or less specific, transcription factors. Here, we review our current knowledge on the function of the eight Yap transcription factors (Yap1 to Yap8) in Saccharomyces cerevisiae, which were shown to be involved in various stress responses. More precisely, Yap1 is activated under oxidative stress, Yap2/Cad1 under cadmium, Yap4/Cin5 and Yap6 under osmotic shock, Yap5 under iron overload and Yap8/Arr1 by arsenic compounds. Yap3 and Yap7 seem to be involved in hydroquinone and nitrosative stresses, respectively. The data presented in this article illustrate how much knowledge on the function of these Yap transcription factors is advanced. The evolution of the Yap family and its roles in various pathogenic and non-pathogenic fungal species is discussed in the last section.

Update on the cellular and molecular aspects of cystic fibrosis transmembrane conductance regulator (CFTR) and male fertility

CFTR protein regulates electrolyte and fluid transport in almost all tissues with exocrine function, including male reproductive tract. Mutation of CFTR gene causes cystic fibrosis (CF), which affects the function of several organs, and impairs male fertility. The role of CFTR protein in different compartments of male reproductive tract (testis, epididymis, sperm) as well as an impact of CFTR mutation(s) on male fertility phenotype is discussed in relation with the choice of optimal technique for Assisted Reproductive Techniques (ART) management.

Transcriptional regulation of FeS biogenesis genes: A possible shield against arsenate toxicity activated by Yap1

In the eukaryotic model yeast Saccharomyces cerevisiae, arsenic (As) detoxification is regulated by two transcriptional factors, Yap8 and Yap1. Yap8 specifically controls As extrusion from the cell, whether Yap1 avoids arsenic-induced oxidative damages. Accordingly, cells lacking both Yap1 and Yap8 are more sensitive to arsenate than cells lacking each regulator individually. Strikingly enough, the same sensitivity pattern was observed under anoxia, suggesting that Yap1 role in As detoxification might not be restricted to the regulation of the oxidative stress response. This finding prompted us to study the transcriptomic profile of wild-type and yap1 mutant cells exposed to arsenate. Interestingly, we found that, under such conditions, several genes involved in the biogenesis of FeS proteins were upregulated in a Yap1-dependent way. In line with this observation, arsenate treatment decreases the activity of the mitochondrial aconitase, Aco1, an FeS cluster-containing enzyme, this effect being even more pronounced in the yap1 mutant. Reinforcing the relevance of FeS cluster biogenesis in arsenate detoxification, the overexpression of several ISC and CIA machinery genes alleviates the deleterious effect of arsenate caused by the absence of Yap1 and Yap8. Altogether our data suggest that the upregulation of FeS biogenesis genes regulated by Yap1 might work as a cellular shield against arsenate toxicity.

Fluid intake of Latin American children and adolescents: results of four 2016 LIQ.IN 7 National Cross-Sectional Surveys

PURPOSE

The primary aim of this survey was to report total fluid intake (TFI) and different fluid types for children (4-9 years) and adolescents (10-17 years) in Mexico, Brazil, Argentina and Uruguay. The second aim was to compare TFI with the adequate intake (AI) of water from fluids as recommended by the USA Institute of Medicine.

METHODS

Data were collected using a validated liquid intake 7-day record (Liq.In 7 ). Participants' characteristics, including age, sex and anthropometric measurements were recorded.

RESULTS

A total of 733 children and 933 adolescents were recruited. Over 75% of children in Uruguay met the IOM's recommended intake. Fewer children in Argentina (64-72%) and Brazil (41-50%) obtained AI and the lowest values were recorded in Mexico (33-44%), where 16% of boys and 14% girls drank 50% or less of the AI. More adolescents in Argentina (42%) met the AIs than other countries; the lowest was in Mexico (28%). Children and adolescents in Mexico and Argentina drank more sugar sweetened beverages than water.

CONCLUSIONS

Large numbers of children and adolescents did not meet AI recommendations for TFI, raising concerns about their hydration status and potential effects on mental and physical well-being. Given the negative effects on children's health, the levels of SSB consumption are worrying.

Fluid intake of Latin American adults: results of four 2016 Liq.In7 national cross-sectional surveys

Purpose

To report total fluid intake (TFI) and the intake of different fluid types in adults (≥ 18 years old) from Mexico, Argentina, Brazil and Uruguay. To compare intakes between countries and with recommended adequate intake (AI) of water from fluids.

Methods

Cross-sectional data were collected using a validated liquid intake 7-day record (Liq.In⁷) in populations from Argentina (n = 1089), Brazil (n = 477), Mexico (n = 1677) and Uruguay (n = 554). Population characteristics, including age, gender, body mass index and socioeconomic level were recorded. Mean TFI was compared with the AI of water from fluids set by the USA Institute of Medicine.

Results

The lowest TFI was recorded in Mexican women (1748 mL/day) and the highest in Argentinean men (2318 mL/day). Median daily TFI was significantly different between countries; Uruguay and Argentina had higher values than Mexico and Brazil. In the former, plain water contributed to only 25% of TFI, the remainder being predominantly from hot beverages. Approximately, a third of adults did not drink enough fluid to meet the recommended AI. High SSB consumption was reported, which was significantly different between countries (p < 0.05), the highest being in Mexico (median 25–75th percentiles): 531 (300–895 mL/day.

Conclusions

This survey highlights the need to increase water consumption and reduce SSB intake in this region to avoid potential associated health risks. These findings may be useful information in monitoring public health policy strategies.

Electronic supplementary material

The online version of this article (10.1007/s00394-018-1724-z) contains supplementary material, which is available to authorized users.

The C-terminal region of the Hot1 transcription factor binds GGGACAAA-related sequences in the promoter of its target genes

Response to hyperosmotic stress in the yeast Saccharomyces cerevisiae involves the participation of the general stress response mediated by Msn2/4 transcription factors and the HOG pathway. One of the transcription factors activated through this pathway is Hot1, which contributes to the control of the expression of several genes involved in glycerol synthesis and flux, or in other functions related to adaptation to adverse conditions. This work provides new data about the interaction mechanism of this transcription factor with DNA. By means of one-hybrid and electrophoretic mobility assays, we demonstrate that the C-terminal region, which corresponds to amino acids 610-719, is the DNA-binding domain of Hot1. We also describe how this domain recognizes sequence 5'-GGGACAAA-3' located in the promoter of gene STL1. The bioinformatics analysis carried out in this work allowed the identification of identical or similar sequences (with up to two mismatches) in the promoter of other Hot1 targets, where central element GGACA was quite conserved among them. Finally, we found that small variations in the sequence recognized by Hot1 may influence its ability to recognize its targets in vivo.

Inhibition of Yap2 activity by MAPKAP kinase Rck1 affects yeast tolerance to cadmium

Yap2 is a cadmium responsive transcription factor that interacts with MAPK-activated protein (MAPKAP) kinase Rck1. We show that Rck1 deletion confers protection against cadmium toxicity and that the mechanism underlying this observation relies on Yap2. Rck1 removal from the yeast genome potentiates Yap2 activity by increasing protein half-life and delaying its nuclear export. As a consequence, several Yap2 antioxidant targets are over-activated by a mechanism that also requires Yap1. Several genes of the cell wall integrity (CWI) pathway are upregulated under cadmium stress in a Yap2 dependent way. We showed that deletion of CWI genes renders yeast cells more sensitive to cadmium. These findings led us to suggest that in response to cadmium stress Yap2 may serve a dual purpose: oxidative stress attenuation and cell wall maintenance.

An HcpR paralog of Desulfovibrio gigas provides protection against nitrosative stress

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Desulfovibrio gigas genome encodes two HcpR paralogs, HcpR1 and HcpR2.

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Cells lacking HcpR1 are less tolerant to NO.

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HcpR1 regulates the expression of several genes related to nitrogen metabolism.

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Phylogenetic analyses indicate that the presence of HcpR paralogs is a common finding among Desulfovibrio species.

Desulfovibrio gigas belongs to the group of sulfate reducing bacteria (SRB). These ubiquitous and metabolically versatile microorganisms are often exposed to reactive nitrogen species (RNS). Nonetheless, the mechanisms and regulatory elements involved in nitrosative stress protection are still poorly understood. The transcription factor HcpR has emerged as a putative regulator of nitrosative stress response among anaerobic bacteria. HcpR is known to orchestrate the expression of the hybrid cluster protein gene, hcp, proposed to be involved in cellular defense against RNS. According to phylogenetic analyses, the occurrence of hcpR paralog genes is a common feature among several Desulfovibrio species. Within the D. gigas genome we have identified two HcpR-related sequences. One of these sequences, hcpR1, was found in the close vicinity of the hcp gene and this finding prompted us to proceed with its functional characterization. We observed that the growth of a D. gigas strain lacking hcpR1 is severely impaired under nitrosative stress. An in silico search revealed several putative targets of HcpR1 that were experimentally validated. The fact that HcpR1 regulates several genes encoding proteins involved in nitrite and nitrate metabolism, together with the sensitive growth phenotype to NO displayed by an hcpR1 mutant strain, strongly supports a relevant role of this factor under nitrosative stress. Moreover, the finding that several Desulfovibrio species possess HcpR paralogs, which have been transmitted vertically in the evolution and diversification of the genus, suggests that these sequences may confer adaptive or survival advantage to these organisms, possibly by increasing their tolerance to nitrosative stress.

Repression of the Low Affinity Iron Transporter Gene FET4: A NOVEL MECHANISM AGAINST CADMIUM TOXICITY ORCHESTRATED BY YAP1 VIA ROX1

Cadmium is a well known mutagenic metal that can enter cells via nonspecific metal transporters, causing several cellular damages and eventually leading to death. In the yeast Saccharomyces cerevisiae, the transcription factor Yap1 plays a key role in the regulation of several genes involved in metal stress response. We have previously shown that Yap1 represses the expression of FET4, a gene encoding a low affinity iron transporter able to transport metals other than iron. Here, we have studied the relevance of this repression in cell tolerance to cadmium. Our results indicate that genomic deletion of Yap1 increases FET4 transcript and protein levels. In addition, the cadmium toxicity exhibited by this strain is completely reversed by co-deletion of FET4 gene. These data correlate well with the increased intracellular levels of cadmium observed in the mutant yap1. Rox1, a well known aerobic repressor of hypoxic genes, conveys the Yap1-mediated repression of FET4. We further show that, in a scenario where the activity of Yap1 or Rox1 is compromised, cells activate post-transcriptional mechanisms, involving the exoribonuclease Xrn1, to compensate the derepression of FET4. Our data thus reveal a novel protection mechanism against cadmium toxicity mediated by Yap1 that relies on the aerobic repression of FET4 and results in the impairment of cadmium uptake.

Genome sequence of the model sulfate reducer Desulfovibrio gigas: a comparative analysis within the Desulfovibrio genus

Desulfovibrio gigas is a model organism of sulfate-reducing bacteria of which energy metabolism and stress response have been extensively studied. The complete genomic context of this organism was however, not yet available. The sequencing of the D. gigas genome provides insights into the integrated network of energy conserving complexes and structures present in this bacterium. Comparison with genomes of other Desulfovibrio spp. reveals the presence of two different CRISPR/Cas systems in D. gigas. Phylogenetic analysis using conserved protein sequences (encoded by rpoB and gyrB) indicates two main groups of Desulfovibrio spp, being D. gigas more closely related to D. vulgaris and D. desulfuricans strains. Gene duplications were found such as those encoding fumarate reductase, formate dehydrogenase, and superoxide dismutase. Complexes not yet described within Desulfovibrio genus were identified: Mnh complex, a v-type ATP-synthase as well as genes encoding the MinCDE system that could be responsible for the larger size of D. gigas when compared to other members of the genus. A low number of hydrogenases and the absence of the codh/acs and pfl genes, both present in D. vulgaris strains, indicate that intermediate cycling mechanisms may contribute substantially less to the energy gain in D. gigas compared to other Desulfovibrio spp. This might be compensated by the presence of other unique genomic arrangements of complexes such as the Rnf and the Hdr/Flox, or by the presence of NAD(P)H related complexes, like the Nuo, NfnAB or Mnh.

Two residues in the basic region of the yeast transcription factor Yap8 are crucial for its DNA-binding specificity

In Saccharomyces cerevisiae, the transcription factor Yap8 is a key determinant in arsenic stress response. Contrary to Yap1, another basic region-leucine zipper (bZIP) yeast regulator, Yap8 has a very restricted DNA-binding specificity and only orchestrates the expression of ACR2 and ACR3 genes. In the DNA-binding basic region, Yap8 has three distinct amino acids residues, Leu26, Ser29 and Asn31, at sites of highly conserved positions in the other Yap family of transcriptional regulators and Pap1 of Schizosaccharomyces pombe. To evaluate whether these residues are relevant to Yap8 specificity, we first built a homology model of the complex Yap8bZIP-DNA based on Pap1-DNA crystal structure. Several Yap8 mutants were then generated in order to confirm the contribution of the residues predicted to interact with DNA. Using bioinformatics analysis together with in vivo and in vitro approaches, we have identified several conserved residues critical for Yap8-DNA binding. Moreover, our data suggest that Leu26 is required for Yap8 binding to DNA and that this residue together with Asn31, hinder Yap1 response element recognition by Yap8, thus narrowing its DNA-binding specificity. Furthermore our results point to a role of these two amino acids in the stability of the Yap8-DNA complex.

Characterization of mitochondrial dicarboxylate/tricarboxylate transporters from grape berries

Grape berries (Vitis vinifera L fruit) exhibit a double-sigmoid pattern of development that results from two successive periods of vacuolar swelling during which the nature of accumulated solutes changes significantly. Throughout the first period, called green or herbaceous stage, berries accumulate high levels of organic acids, mainly malate and tartrate. At the cellular level fruit acidity comprises both metabolism and vacuolar storage. Malic acid compartmentation is critical for optimal functioning of cytosolic enzymes. Therefore, the identification and characterization of the carriers involved in malate transport across sub-cellular compartments is of great importance. The decrease in acid content during grape berry ripening has been mainly associated to mitochondrial malate oxidation. However, no Vitis vinifera mitochondrial carrier involved in malate transport has been reported to date. Here we describe the identification of three V. vinifera mitochondrial dicarboxylate/tricarboxylate carriers (VvDTC1-3) putatively involved in mitochondrial malate, citrate and other di/tricarboxylates transport. The three VvDTCs are very similar, sharing a percentage of identical residues of at least 83 %. Expression analysis of the encoding VvDTC genes in grape berries shows that they are differentially regulated exhibiting a developmental pattern of expression. The simultaneous high expression of both VvDTC2 and VvDTC3 in grape berry mesocarp close to the onset of ripening suggests that these carriers might be involved in the transport of malate into mitochondria.

Role of NorR-like transcriptional regulators under nitrosative stress of the δ-proteobacterium, Desulfovibrio gigas

NorR protein was shown to be responsible for the transcriptional regulation of flavorubredoxin and its associated oxidoreductase in Escherichia coli. Since Desulfovibrio gigas has a rubredoxin:oxygen oxidoreductase (ROO) that is involved in both oxidative and nitrosative stress response, a NorR-like protein was searched in D. gigas genome. We have found two putative norR coding units in its genome. To study the role of the protein designated as NorR1-like (NorR1L) in the presence of nitrosative stress, a norR1L null mutant of D. gigas was created and a phenotypic analysis was performed under the nitrosating agent GSNO. We show that under these conditions, the growth of both D. gigas mutants Δroo and ΔnorR1-like is impaired. In order to confirm that D. gigas NorR1-like may play identical function as the NorR of E. coli, we have complemented the E. coli ΔnorR mutant strain with the norR1-like gene and have evaluated growth when nitrosative stress was imposed. The growth phenotype of E. coli ΔnorR mutant strain was recovered under these conditions. We also found that induction of roo gene expression is completely abolished in the norR1L mutant strain of D. gigas subjected to nitrosative stress. It is identified in δ-proteobacteria, for the first time a transcription factor that is involved in nitrosative stress response and regulates the rd-roo gene expression.

Arsenic stress elicits cytosolic Ca(2+) bursts and Crz1 activation in Saccharomyces cerevisiae

Although arsenic is notoriously poisonous to life, its utilization in therapeutics brings many benefits to human health, so it is therefore essential to discover the molecular mechanisms underlying arsenic stress responses in eukaryotic cells. Aiming to determine the contribution of Ca(2+) signalling pathways to arsenic stress responses, we took advantage of the use of Saccharomyces cerevisiae as a model organism. Here we show that Ca(2+) enhances the tolerance of the wild-type and arsenic-sensitive yap1 strains to arsenic stress in a Crz1-dependent manner, thus providing the first evidence that Ca(2+) signalling cascades are involved in arsenic stress responses. Moreover, our results indicate that arsenic shock elicits a cytosolic Ca(2+) burst in these strains, without the addition of exogenous Ca(2+) sources, strongly supporting the notion that Ca(2+) homeostasis is disrupted by arsenic stress. In response to an arsenite-induced increase of Ca(2+) in the cytosol, Crz1 is dephosphorylated and translocated to the nucleus, and stimulates CDRE-driven expression of the lacZ reporter gene in a Cnb1-dependent manner. The activation of Crz1 by arsenite culminates in the induction of the endogenous genes PMR1, PMC1 and GSC2. Taken together, these data establish that activation of Ca(2+) signalling pathways and the downstream activation of the Crz1 transcription factor contribute to arsenic tolerance in the eukaryotic model organism S. cerevisiae.

The role of the Yap5 transcription factor in remodeling gene expression in response to Fe bioavailability

The budding yeast Saccharomyces cerevisiae has developed several mechanisms to avoid either the drastic consequences of iron deprivation or the toxic effects of iron excess. In this work, we analysed the global gene expression changes occurring in yeast cells undergoing iron overload. Several genes directly or indirectly involved in iron homeostasis showed altered expression and the relevance of these changes are discussed. Microarray analyses were also performed to identify new targets of the iron responsive factor Yap5. Besides the iron vacuolar transporter CCC1, Yap5 also controls the expression of glutaredoxin GRX4, previously known to be involved in the regulation of Aft1 nuclear localization. Consistently, we show that in the absence of Yap5 Aft1 nuclear exclusion is slightly impaired. These studies provide further evidence that cells control iron homeostasis by using multiple pathways.

Yap4 PKA- and GSK3-dependent phosphorylation affects its stability but not its nuclear localization

Yap4 is a nuclear-resident transcription factor induced in Saccharomyces cerevisiae when exposed to several stress conditions, which include mild hyperosmotic and oxidative stress, temperature shift or metal exposure. This protein is also phosphorylated. Here we report that this modification is driven by PKA and GSK3. In order to ascertain whether Yap4 is directly or indirectly phosphorylated by PKA, we searched for stress and PKA-related kinases that could phosphorylate Yap4. We show that phosphorylation is independent of the kinases Rim15, Yak1, Sch9, Slt2, Ste20 and Ptk2. In addition, we showed that Yap4 phosphorylation is also abrogated in the triple GSK3 mutant mck1 rim11 yol128c. Furthermore, our data reveal that Yap4 nuclear localization is independent of its phosphorylation state. This protein has several putative phosphorylation sites, but only the mutation of residues T192 and S196 impairs its phosphorylation under different stress conditions. The ability of the non-phosphorylated forms of Yap4 to partially rescue the hog1 severe sensitivity phenotype is not affected, suggesting that Yap4 activity is maintained in the absence of phosphorylation. However, this modification seems to be required for stability of the protein, as the non-phosphorylated form has a shorter half-life than the phosphorylated one.

Characterization and expression analysis of the aspartic protease gene family of Cynara cardunculus L

Cardosin A and cardosin B are two aspartic proteases mainly found in the pistils of cardoon Cynara cardunculus L., whose flowers are traditionally used in several Mediterranean countries in the manufacture of ewe's cheese. We have been characterizing cardosins at the biochemical, structural and molecular levels. In this study, we show that the cardoon aspartic proteases are encoded by a multigene family. The genes for cardosin A and cardosin B, as well as those for two new cardoon aspartic proteases, designated cardosin C and cardosin D, were characterized, and their expression in C. cardunculus L. was analyzed by RT-PCR. Together with cardosins, a partial clone of the cyprosin B gene was isolated, revealing that cardosin and cyprosin genes coexist in the genome of the same plant. As a first approach to understanding what dictates the flower-specific pattern of cardosin genes, the respective gene 5' regulatory sequences were fused with the reporter beta-glucuronidase and introduced into Arabidopsis thaliana. A subsequent deletion analysis of the promoter region of the cardosin A gene allowed the identification of a region of approximately 500 bp essential for gene expression in transgenic flowers. Additionally, the relevance of the leader intron of the cardosin A and B genes for gene expression was evaluated. Our data showed that the leader intron is essential for cardosin B gene expression in A. thaliana. In silico analysis revealed the presence of potential regulatory motifs that lay within the aforementioned regions and therefore might be important in the regulation of cardosin expression.

Solution structure of two insect-specific spider toxins and their pharmacological interaction with the insect voltage-gated Na+ channel

Delta-paluIT1 and delta-paluIT2 are toxins purified from the venom of the spider Paracoelotes luctuosus. Similar in sequence to mu-agatoxins from Agelenopsis aperta, their pharmacological target is the voltage-gated insect sodium channel, of which they alter the inactivation properties in a way similar to alpha-scorpion toxins, but they bind on site 4 in a way similar to beta-scorpion toxins. We determined the solution structure of the two toxins by use of two-dimensional nuclear magnetic resonance (NMR) techniques followed by distance geometry and molecular dynamics. The structures of delta-paluIT1 and delta-paluIT2 belong to the inhibitory cystine knot structural family, i.e. a compact disulfide-bonded core from which four loops emerge. Delta-paluIT1 and delta-paluIT2 contain respectively two- and three-stranded anti-parallel beta-sheets as unique secondary structure. We compare the structure and the electrostatic anisotropy of those peptides to other sodium and calcium channel toxins, analyze the topological juxtaposition of key functional residues, and conclude that the recognition of insect voltage-gated sodium channels by these toxins involves the beta-sheet, in addition to loops I and IV. Besides the position of culprit residues on the molecular surface, difference in dipolar moment orientation is another determinant of receptor binding and biological activity differences. We also demonstrate by electrophysiological experiments on the cloned insect voltage-gated sodium channel, para, heterologuously co-expressed with the tipE subunit in Xenopus laevis oocytes, that delta-paluIT1 and delta-paluIT2 procure an increase of Na+ current. delta-PaluIT1-OH seems to have less effect when the same concentrations are used.

Influence of insulin-like growth factor-I and its interaction with gonadotropins, estradiol, and fetal calf serum on in vitro maturation and parthenogenic development in equine oocytes

The effects of insulin-like growth factor-I (IGF-I) and its interaction with gonadotropins, estradiol, and fetal calf serum (FCS) on in vitro maturation (IVM) of equine oocytes were investigated in this study. We also examined the role of IGF-I in the presence or absence of gonadotropins, estradiol, and FCS in parthenogenic cleavage after oocyte activation with calcium ionophore combined with 6-dimethylaminopurine (6-DMAP), using cleavage rate as a measure of cytoplasmic maturation. Only equine cumulus-oocyte complexes with compact cumulus and homogenous ooplasm (n = 817) were used. In experiment 1, oocytes were cultured in TCM-199 supplemented with BSA, antibiotics, and IGF-I at 0 (control), 50, 100, 200 ng/ml, at 39 degrees C in air with 5% CO(2), 95% humidity for 36 or 48 h. In experiment 2, oocytes were cultured with FSH, LH, estradiol, and FCS with IGF-I at the concentration that promoted the highest nuclear maturation rate in experiment 1. In experiment 3, oocytes from the three experimental groups (IGF-I; hormones; and IGF-I + hormones) were chemically activated by exposure to calcium ionophore followed by culture in 6-DMAP. In experiment 1, IGF-I stimulated equine oocyte maturation in a dose-dependent manner with the highest nuclear maturation rate at a concentration of 200 ng/ml. No significant effect of IGF-I on nuclear maturation was observed in experiment 2. In experiment 3, a significant difference in cleavage rate was observed between the hormone + IGF-I group (15 of 33; 45.4%) compared with IGF-I (10 of 36; 27.8%) and hormone (4 of 31; 12.9%) alone (P < 0.05). These results demonstrated that IGF-I has a positive effect on nuclear maturation rate of equine oocytes in vitro. The addition of IGF-I to an IVM medium containing hormones and FCS did not increase nuclear maturation, but resulted in a positive effect on cytoplasmic maturation of equine oocytes measured by parthenogenic cleavage.

Differences in growth and water relations among Phaseolus vulgaris cultivars in response to induced drought stress

Relatively little ecophysiological research has been conducted to determine the responses to drought of Phaseolus vulgaris. Four bean cultivars (cvs.) from Brazil, A320, Carioca, Ouro Negro and Xodó were submitted to an imposed water deficit in order to evaluate the importance of some adaptive mechanisms of drought resistance through the analysis of growth parameters, water status, gas exchange and indicators of tolerance mechanisms at the cellular level. During the drought treatment, relative growth rates were more reduced for A320 and Xodó than Carioca and Ouro Negro. A320 closed its stomata very rapidly and complete stomatal closure was obtained at Psi(w)=-0.6 MPa, in contrast to the other cvs. where stomata were fully closed only at Psi(w)=-0.9 MPa. Net assimilation rates were closely related to stomatal conductances. Mechanisms at the cellular level appeared to be mostly important for higher tolerance. Carioca and Ouro Negro, when compared to A320 and Xodó, were characterized by having better drought tolerance mechanisms and higher tissue water retention capacity leading to a better growth under water deficits. The leaf dehydration rates of those cvs. were slow whereas those of the drought sensitive cvs. were rapid. The results were confirmed by the electrolyte leakage test and leaf osmotic potential measurements, which indicated higher membrane resistance and osmotic adjustment in the two tolerant cvs. Carioca and Ouro Negro. It appears from this study that despite being cultivated in the same geographical region, the four cvs. of P. vulgaris displayed somewhat different drought adaptive capacities for prolonged drought during the vegetative phase.

Small bowel motility in primary biliary cirrhosis

OBJECTIVE

Previous studies have shown small bowel motor activity abnormalities in patients with liver cirrhosis of different etiologies, but motility has not been studied in patients with primary biliary cirrhosis. Our aim was to investigate proximal small bowel motility in these patients.

METHODS

Twenty-five female patients presenting clinical, biochemical, serological, and histological findings compatible with primary biliary cirrhosis, 10 female patients with nonalcoholic liver cirrhosis, and 10 normal female controls were studied. Motility of the upper small bowel was measured in the fasted state by means of perfused manometric catheters, connected to external transducers and positioned in the small bowel under fluoroscopy.

RESULTS

The average amplitude of contractions was significantly decreased in patients with primary biliary cirrhosis compared with other liver cirrhosis (20.2+/-1.0 vs 32+/-2.9 mm Hg). Also, a significantly increased frequency of cluster of contractions and an increased duration of phase II of the migrating motor complex as seen in liver cirrhosis was observed when compared with normals.

CONCLUSION

We conclude that primary biliary cirrhosis patients present motor abnormalities of the small intestine similar to those of patients with liver cirrhosis of other etiologies. In addition, a decrease in the amplitude of small bowel contractions was also found in these patients, suggesting a myogenic involvement.

[Endoscopic manometry of Oddi's sphincter]

BACKGROUND

Endoscopic manometry is the gold standard for the diagnosis of sphincter of Oddi dysfunction.

AIM

To report the results of the first 30 endoscopic manometries of sphincter of Oddi performed in a Gastroenterology Service.

PATIENTS AND METHODS

Thirty manometries were performed in 28 patients aged 30 to 70 years old (14 females). The papilla was cannulated with a perfused catheter, measuring pressure with external transducers.

RESULTS

Deep cannulation of the papilla was achieved in 88%. Procedure-related complications were not observed in these cases. Normal values were registered in 11 cases with a basal sphincter pressure 15.6 +/- 10.7 mm Hg, contractions with an amplitude of 92.3 +/- 35.7 mm Hg and 6.0 +/- 2.4/min frequency. The clinical suspicion of hypertonic dyskinesis was confirmed in 5 cases with an elevated basal pressure of 43.69 +/- 13.3 mm Hg, an increased frequency of contractions ("tachyoddia") in one, and large spastic contractions of high pressure in other case. In 3 of 5 cases with common bile duct stones, a predominance of retrograde propagation of the contractions was observed with normal pressure. Variable manometric results were observed after endoscopic papillotomy observing a scale from the complete absence of motor activity to normal sphincter function.

CONCLUSIONS

Endoscopic manometry is a reasonably safe method, of great importance in the diagnosis of functional disorders of the sphincter of Oddi.

Testicular function in asymptomatic chronic alcoholics: relation to ethanol intake

To evaluate the effect of ethanol on testicular function in chronic alcoholics without chronic liver disease, we studied 38 asymptomatic chronic alcoholics and 19 age-matched controls. Detailed clinical history, nutritional status, hormonal analysis, and seminal studies were conducted in each case and control. Alcoholic patients had an average of 39 +/- 2 years old (range: 26 to 60) and reported a daily ethanol consumption from 100 to 350 g (mean: 198 +/- 15) over a period of 18.0 +/- 1.2 years. Alcoholics exhibited a significant increase of the luteinizing hormone (p < 0.001) and a decrease of the Free Androgen Index, compared with controls (p < 0.05) that related significantly with the total lifetime dose of ethanol (p < 0.01, both). Seminal studies indicate that 39.4% of alcoholics had significantly reduced their spermatozoa count (p < 0.01), whereas significant morphological abnormalities were observed in 44.7% of the alcoholics (p < 0.01). Spermatozoa motility from alcoholics was also found to be altered in half of the patients (p < 0.01). A significant increase of serum luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin levels, and a decrease of Free Androgen Index were observed in alcoholics with morphology and motility abnormalities (p < 0.05, all). In multivariate analysis, the only independent factor that determined the alterations in sperm (count, morphology abnormalities, and motility alterations) was the total lifetime of ethanol intake (p < 0.001, all). We conclude that alcoholics frequently develop a situation of primary hypogonadism related to a lifetime of ethanol consumption.

Late low-dose pure follicle stimulating hormone for ovarian stimulation in intra-uterine insemination cycles

At present, there is general agreement that ovarian stimulation improves pregnancy rates after intra-uterine insemination (IUI). Also, ovulation induction with gonadotrophins is associated with higher success rates than clomiphene citrate in IUI cycles. However, the drawbacks to the use of gonadotrophin stimulation before IUI include the risks of ovarian hyperstimulation and multiple gestation, and the relative cost of a treatment cycle in a view of the medication costs and the need for increased monitoring by hormone assays and ultrasonographic measurements. In the present prospective randomized trial, the efficacy and safety of ovarian stimulation with clomiphene citrate (50 mg/day for 5 days) and IUI (clomiphene/IUI group) were compared with those of late low-dose pure follicle stimulating hormone (FSH, 75 IU/day from day cycle 7 until the leading follicle reached > 17 mm in diameter) and IUI (FSH/IUI group) in ovulatory women who were infertile because of unexplained infertility (n = 40) or male subfertility (n = 60). The mean length of treatment in the FSH group was 6.4 +/- 2.5 days. Multiple follicular development was seen in 25% of clomiphene-stimulated cycles but only in 8% of those treated with FSH. Pregnancy rate per cycle in clomiphene/IUI and FSH/IUI groups was 4% (4/98) and 13% (12/94) respectively (P = 0.02). All pregnancies obtained were singleton. There were two and one clinical abortions in the clomiphene/IUI (50%) and FSH/IUI (8%) groups respectively. No patient developed ovarian hyperstimulation syndrome. Use of our therapeutic scheme, which proved to be efficacious, safe and economic for ovarian stimulation in IUI cycles, is advocated before the institution of in-vitro fertilization (IVF) or gamete intra-Fallopian transfer (GIFT) therapy in infertile patients with patient Fallopian tubes. This late low-dose technique of administering pure FSH is suitable for use in offices without immediate access to oestradiol results.

Immunobiochemical evidence for the loss of sperm specific histones during male pronucleus formation in monospermic zygotes of sea urchins

To obtain information on the remodeling of sperm chromatin during male pronuclei formation, we have followed the sperm specific histones (SpH) that form the nucleosomal core by Western immunoblot analysis with polyclonal antibodies directed against the core SpH. The results obtained indicate that the complete set of SpH is absent from zygote chromatin at the beginning of the first S phase. The disappearance of SpH is not coincidental for the five histone classes: SpH4 and SpH3 are lost 5-15 min post insemination (p.i.), SpH2B and SpH2A disappear 20-40 min p.i., and SpH1 is progressively diminished up to 30 min p.i. This order of sperm chromatin remodeling is not affected by the inhibition of protein synthesis by emetine, indicating that the factor(s) responsible for SpH disappearance are present in unfertilized eggs. The lost SpH's are not replaced by newly synthesized CS variants, since the basic proteins synthesized de novo during male pronuclei formation are not incorporated into chromatin remaining in the cytoplasm. These newly synthesized proteins are different from the CS variants as judged by their electrophoretic migration.

[Tumor markers in liver metastases of colorectal carcinoma]

Colorectal cancer is a potentially curable tumour when diagnosed in the early stages. In order to improve the results obtained up to now, we propose application of a diagnostic program among patients who undergo curative resection for colorectal adenocarcinoma, which would consist of using a panel of tumor markers, in combination with endoscopic, histologic and ultrasonographic diagnostic methods. For this study we studied 105 patients, divided into two groups: A) Group 1: 30 control patients. B) Group 2: 75 patients diagnosed as having colorectal cancer. We performed the preoperative determination of a series of tumor markers (CEA, CA 19.9, GGT and PHI), endoscopy/biopsy and hepatic ultrasonography on these patients. Our results suggest that the design of the preoperative diagnostic program makes early detection of hepatic metastases possible. The tumor marker panel combination provided a visible increase in sensitivity for detecting hepatic metastases.

Chronic administration of cannabidiol to healthy volunteers and epileptic patients

In phase 1 of the study, 3 mg/kg daily of cannabidiol (CBD) was given for 30 days to 8 health human volunteers. Another 8 volunteers received the same number of identical capsules containing glucose as placebo in a double-blind setting. Neurological and physical examinations, blood and urine analysis, ECG and EEG were performed at weekly intervals. In phase 2 of the study, 15 patients suffering from secondary generalized epilepsy with temporal focus were randomly divided into two groups. Each patient received, in a double-blind procedure, 200-300 mg daily of CBD or placebo. The drugs were administered for along as 4 1/2 months. Clinical and laboratory examinations, EEG and ECG were performed at 15- or 30-day intervals. Throughout the experiment the patients continued to take the antiepileptic drugs prescribed before the experiment, although these drugs no longer controlled the signs of the disease. All patients and volunteers tolerated CBD very well and no signs of toxicity or serious side effects were detected on examination. 4 of the 8 CBD subjects remained almost free of convulsive crises throughout the experiment and 3 other patients demonstrated partial improvement in their clinical condition. CBD was ineffective in 1 patient. The clinical condition of 7 placebo patients remained unchanged whereas the condition of 1 patient clearly improved. The potential use of CBD as an antiepileptic drug and its possible potentiating effect on other antiepileptic drugs are discussed.

Coronary embolism

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