Global hypomethylation and promoter methylation in small intestinal neuroendocrine tumors: An in vivo and in vitro study

Aberrant DNA methylation is a feature of human cancer affecting gene expression and tumor phenotype. Here, we quantified promoter methylation of candidate genes and global methylation in 44 small intestinal-neuroendocrine tumors (SI-NETs) from 33 patients by pyrosequencing. Findings were compared with gene expression, patient outcome and known tumor copy number alterations. Promoter methylation was observed for WIF1, RASSF1A, CTNNB1, CXCL14, NKX2–3, P16, LAMA1, and CDH1. By contrast APC, CDH3, HIC1, P14, SMAD2, and SMAD4 only had low levels of methylation. WIF1 methylation was significantly increased (P = 0.001) and WIF1 expression was reduced in SI-NETs vs. normal references (P = 0.003). WIF1, NKX2–3, and CXCL14 expression was reduced in metastases vs. primary tumors (P < 0.02). Low expression of RASSF1A and P16 were associated with poor overall survival (P = 0.045 and P = 0.011, respectively). Global methylation determined by pyrosequencing of LINE1 repeats was reduced in tumors vs. normal references, and was associated with loss in chromosome 18. The tumors fell into three clusters with enrichment of WIF1 methylation and LINE1 hypomethylation in Cluster I and RASSF1A and CTNNB1 methylation and loss in 16q in Cluster II. In Cluster III, these alterations were low-abundant and NKX2-3 methylation was low. Similar analyses in the SI-NET cell lines HC45 and CNDT2 showed methylation for CDH1 and WIF1 and/or P16, CXCL14, NKX2-3, LAMA1, and CTNNB1. Treatment with the demethylating agent 5-azacytidine reduced DNA methylation and increased expression of these genes in vitro. In conclusion, promoter methylation of tumor suppressor genes is associated with suppressed gene expression and DNA copy number alterations in SI-NETs, and may be restored in vitro.     

Ixodid Tick Infestation in Cattle and Wild Animals in Maswa and Iringa,Tanzania

Ticks and tick-borne diseases are important in human and livestock health worldwide. In November 2012, ixodid ticks were collected and identified morphologically from cattle and wild animals in the Maswa district and Iringa urban, Tanzania. Amblyomma gemma, A. lepidum, and A. variegatum were identified from Maswa cattle, and A. variegatum was the predominant species. A. marmoreum, Hyalomma impeltatum, and Rhipicephalus pulchellus were identified from Iringa cattle in addition to the above 3 Amblyomma species, and A. gemma was the most abundant species. Total 4 Amblyomma and 6 Rhipicephalus species were identified from wild animals of the 2 areas. A. lepidum was predominant in Maswa buffaloes, whereas A. gemma was predominant in Iringa buffaloes. Overall, A. variegatum in cattle was predominant in the Maswa district and A. gemma was predominant in Iringa, Tanzania.     

Expression of key myogenic,fibrogenic and adipogenic genes in Longissimus thoracis and Masseter muscles in cattle

Adipogenesis, myogenesis and fibrogenesis are related processes that can contribute to meat quality. Therefore, extending the knowledge of these processes would facilitate the identification of molecular markers that predict intramuscular fat accretion. The main purpose of this work, based on previous results, was to further study the expression of key genes related to adipogenic, myogenic, fibrogenic processes and some cytokines in Longissimus thoracis (LT) and Masseter (MS) muscles of Pirenaica and Holstein young bulls. Longissimus thoracis and MS muscles from Pirenaica (n = 4) and Spanish Holstein (n = 4) were sampled for proximate analysis, determination of adipocyte size distribution and expression of key candidate genes. Fat percentage was lower in LT than in MS muscle in Pirenaica young bulls (P = 0.023) and was higher in LT muscle in Holstein than in Pirenaica young bulls (P = 0.007). Gene expression analysis revealed that the mRNA level of myogenic differentiation 1 (MYOD) was higher in LT than in MS muscles in both groups of animals (P < 0.001) and that myostatin (MSTN) expression was also higher in LT than in MS muscle in Holstein bulls (P = 0.001). On the other hand, MSTN and PPARG showed higher expression in LT and MS in Pirenaica young bulls (P = 0.026), while the expression of fatty acid-binding protein 4 (FABP4) was higher in Holstein young bulls, also in both muscles (P < 0.001). The results suggested that the development of intramuscular adipose depot was directly related to the expression of adipogenic genes, such as FABP4, but inversely related to the expression of the cytokine MSTN and the myogenic gene MYOD, genes which showed a muscle-specific expression.     

Nutrient restriction and realimentation in beef cows during early and mid-gestation and maternal and fetal hepatic and small intestinal in vitro oxygen consumption

Objectives were to determine the effects of advancing gestation, maternal nutrient restriction during early and mid-gestation, and realimentation on fetal liver and jejunal mass and energy use in both dams and fetuses. On day 30 of pregnancy, multiparous, non-lactating beef cows (initial BW=621±11.3 kg and body condition score=5.1±0.1) were assigned to one of the two dietary treatments: control (CON; 100% requirements; n=18) and restricted (R; 60% requirements; n=28). On day 85, cows were slaughtered (CON, n=6; R, n=6), and remaining cows continued on control (CC; n=12) and restricted (RR; n=12) diets, or were realimented to the control diet (RC; n=11). On day 140, cows were slaughtered (CC, n=6; RR, n=6; RC, n=5), remaining cows continued on the control diet (CCC, n=6; RCC, n=5), or were realimented to the control diet (RRC, n=6). On day 254, all remaining cows were slaughtered. Maternal liver O₂ consumption linearly increased (P⩽0.04) and jejunal weight (g/kg) linearly decreased (P=0.04) as gestation advanced in CON groups. Fetal BW, and hepatic and small intestinal absolute mass, protein content and O₂ consumption linearly increased (P⩽0.04) as pregnancy advanced in CON groups. However, mass and O₂ consumption relative to BW linearly decreased (P⩽0.001) in the fetal liver in CON groups. When analyzing the effects of dietary treatment, at day 85, fetal jejunal O₂ consumption (mol/min per kg BW) was lower (P=0.02) in the R group when compared with the CON group. At day 140, maternal hepatic weight (g) was lower (P=0.02) in RC and RR cows when compared with CC, and fetal jejunual O₂ consumption (mmol/min per mg tissue and mmol/min per g protein) was greater (P⩽0.02) in RC when compared with RR. At day 254, maternal hepatic O₂ consumption (absolute and relative to BW) was lower (P⩽0.04) in the RCC cows when compared with RRC. Fetal hepatic weight was lower (P=0.05) in the CCC group when compared with RCC and RRC. The changes in response to nutrient restriction and realimentation in both the dam and fetus may indicate an adaptation to a lower amount of available nutrients by altering tissue mass and metabolism.     

Expression of the Phytophthora infestans ipiB and ipi0 genes in planta and in vitro

The ipiB and ipiO genes of the potato late blight fungus Phytophthora infestans (Mont.) de Bary were isolated from a genomic library in a screen for genes induced in planta. Expression of these genes was studied during pathogenesis on various host tissues and different host plants, some of which show specific resistance against P. infestans infection. During pathogenesis on leaves and tubers of the fully susceptible potato cultivar (cv.) Ajax and on leaves of the fully susceptible tomato cv. Moneymaker, the P. infestans ipiB and ipiO genes show a transient expression pattern with highest mRNA levels in the early stages of infection. During the interaction with leaves of the partially resistant potato cv. Pimpernel, the expression is also transient but accumulation and disappearance of the mRNAs is delayed. Also in P. infestans inoculated onto a race-specific resistant potato cultivar and onto the nonhost Solanum nigrum, ipiB and ipiO mRNA is detectable during the initial stages of infection. Apparently, the expression of the ipiB and the ipiO genes is activated in compatible, incompatible and nonhost interactions. In encysted zoospores, ipiB and ipiO mRNA accumulation was not detectable, but during cyst germination and appressorium formation on an artificial surface the genes are highly expressed. Expression studies in mycelium grown in vitro revealed that during nutrient starvation the expression of the ipiB and ipiO genes is induced. For ipiO gene expression, carbon deprivation appeared to be sufficient. The ipiO gene promoters contain a sequence motif that functions as a glucose repression element in yeast and this motif might be involved in the regulation of ipiO gene expression.     

Antimalarial and antitubercular nostocarboline and eudistomin derivatives: Synthesis,in vitro and in vivo biological evaluation

The synthesis of nine nostocarboline derivatives with substitutions of the 2-methyl group by alkyl, aryl and functionalized residues, 10 symmetrical bis cationic dimers linking 6-Cl-norharmane through the 2-position and fifteen derivatives of the marine alkaloids eudistomin N and O is reported. These compounds were evaluated in vitro against four parasites (Trypanosoma brucei rhodesiense STIB 900, Trypanosoma cruzi Tulahuen C2C4, Leishmania donovani MHOM-ET-67/L82 axenic amastigotes, and Plasmodium falciparum K1 strain), against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc²155 and Corynebacterium glutamicum ATCC13032, and cytotoxicity was determined against L6 rat myoblast cells. Nostocarboline and derivatives displayed potent and selective in vitro inhibition of P. falciparum with weak cytotoxicity. The dimers displayed submicromolar inhibition of L. donovani and T. brucei, and nanomolar activity against P. falciparum, albeit with pronounced cytotoxicity. One dimer showed a MIC₉₉ value against M. tuberculosis of 2.5 μg/ml. The alkylated eudistomin N and O derivatives displayed activities down to 18 nM against P. falciparum for N-Me Eudistomin N. Four dimers, nostocarboline and three eudostomin derivatives were evaluated in an in vivo Plasmodium berghei mouse model. No significant activity was observed for the dimers, but a 50% reduction in parasitaemia was observed at 4 × 50 mg/kg ip for nostocarboline.     

Temporal and Spatial Variation in the Abundance of Total and Pathogenic Vibrio parahaemolyticus in Shellfish in China

We investigated the abundance of total and pathogenic Vibrio parahaemolyticus in shellfish sampled from four provinces in China during May 2013 and March 2014 using the most probable number-polymerase chain reaction (MPN-PCR) method. Total V. parahaemolyticus was detected in 67.7% of 496 samples. A total of 38.1% and 10.1% of samples exceeded 1,000 MPN g^-1 and 10,000 MPN g^-1, respectively. V. parahaemolyticus densities followed a seasonal and geographical trend, with Guangxi and Sichuan shellfish possessing total V. parahaemolyticus levels that were 100-fold higher than those of the Liaoning and Shandong regions. Moreover, the levels of V. parahaemolyticus were at least 10-fold higher in the summer and autumn than in the cooler seasons. Pathogenic V. parahaemolyticus levels were generally lower than total V. parahaemolyticus levels by several log units and tended to be high in samples contaminated with high total V. parahaemolyticus levels. The aqua farms had a lower prevalence but higher abundance of total V. parahaemolyticus compared to retail markets. The catering markets showed the lowest levels of total V. parahaemolyticus, but 20.0% of samples exceeded 1,000 MPN g^-1. The levels of both total and pathogenic V. parahaemolyticus in oysters were higher than in clams. The log-transformed abundance of V. parahaemolyticus was significantly correlated with both water temperature and air temperature but not water salinity. These results provide baseline contamination data of V. parahaemolyticus in shellfish in China, which can be applied to local risk assessments to prioritize risk control to key sectors and evaluate the effectiveness of future control measures.     

Changes in aminoacidergic and monoaminergic neurotransmission in the hippocampus and amygdala of rats after ayahuasca ingestion

AIM: To evaluate changes in neurotransmission induced by a psychoactive beverage ayahuasca in the hippocampus and amygdala of naive rats. METHODS: The level of monoamines, their main metabolites and amino acid neurotransmitters concentrations were quantified using high performance liquid chromatography(HPLC). Four groups of rats were employed: saline-treated and rats receiving 250, 500 and 800 mg/kg of ayahuasca infusion(gavage). Animals were killed 40 min after drug ingestion and the structures stored at-80 ℃ until HPLC assay. The data from all groups were compared using Analysis of variance and Scheffé as post test and P 0.05 was accepted as significant. RESULTS: The results showed decreased concentrations of glycine(GLY)(0.13 ± 0.03 vs 0.29 ± 0.07, P 0.001) and γ-aminobutyric acid(GABA)(1.07 ± 0.14 vs 1.73 ± 0.25, P 0.001) in the amygdala of rats that received 500 of ayahuasca. Animals that ingested 800 mg/kg of ayahuasca also showed a reduction of GLY level(0.11 ± 0.01 vs 0.29 ± 0.07, P 0.001) and GABA(0.98 ± 0.06 vs 1.73 ± 0.25, P 0.001). In the hippocampus, increased GABA levels were found in rats that received all ayahuasca doses: 250 mg/kg(1.29 ± 0.19 vs 0.84 ± 0.21, P 0.05); 500 mg/kg(2.23 ± 038 vs 084 ± 0.21, P 0.05) and 800 mg/kg(1.98 ± 0.92 vs 0.84 ± 0.21, P 0.05). In addition, an increased utilization rate of all monoamines was found in the amygdala after ayahuasca administration in doses: 250 mg/kg(noradrenaline: 0.16 ± 0.02 vs 0.36 ± 0.06, P 0.01; dopamine: 0.39 ± 0.012 vs 2.39 ± 0.84, P 0.001; serotonin: 1.02 ± 0.22 vs 4.04 ± 0.91, P 0.001), 500 mg/kg(noradrenaline: 0.08 ± 0.02 vs 0.36 ± 0.06, P 0.001; dopamine: 0.33 ± 0.19 vs 2.39 ± 0.84, P 0.001; serotonin: 0.59 ± 0.08 vs 4.04 ± 0.91, P 0.001) and 800 mg/kg(noradrenaline: 0.16 ± 0.04 vs 0.36 ± 0.06, P 0.001; dopamine: 0.84 ± 0.65 vs2.39 ± 0.84, P 0.05; serotonin: 0.36 ± 0.02 vs 4.04 ± 0.91, P 0.001). CONCLUSION: Our data suggest increased release of inhibitory amino acids by the hippocampus and an increased utilization rate of monoamines by the amygdala after different doses of ayahuasca ingestion.     

Plasmid Transfer between the Bacillus thuringiensis Subspecies kurstaki and tenebrionis in Laboratory Culture and Soil and in Lepidopteran and Coleopteran Larvae

Plasmid transfer between Bacillus thuringiensis subsp. kurstaki HD1 and B. thuringiensis subsp. tenebrionis donor strains and a streptomycin-resistant B. thuringiensis subsp. kurstaki recipient was studied under environmentally relevant laboratory conditions in vitro, in soil, and in insects. Plasmid transfer was detected in vitro at temperatures of 5 to 37°C, at pH 5.9 to 9.0, and at water activities of 0.965 to 0.995, and the highest transfer ratios (up to 10⁻¹ transconjugant/donor) were detected within 4 h. In contrast, no plasmid transfer was detected in nonsterile soil, and rapid formation of spores by the introduced strains probably contributed most to the lack of plasmid transfer observed. When a B. thuringiensis subsp. kurstaki strain was used as the donor strain, plasmid transfer was detected in killed susceptible lepidopteran insect (Lacanobia oleracea) larvae but not in the nonsusceptible coleopteran insect Phaedon chocleriae. When a B. thuringiensis subsp. tenerbrionis strain was used as the donor strain, no plasmid transfer was detected in either of these insects even when they were killed. These results show that in larger susceptible lepidopteran insects there is a greater opportunity for growth of B. thuringiensis strains, and this finding, combined with decreased competition due to a low initial background bacterial population, can provide suitable conditions for efficient plasmid transfer in the environment.     

Synthesis and degradation of termination and premature-termination fragments of beta-galactosidase in vitro and in vivo.

A number of abnormal polypeptides which are products of the lacZ gene in Escherichia coli have been characterized. A variety of experiments indicates that one class of at least nine different fragments arises from premature termination of protein synthesis. They have been detected as products of protein synthesis both in vitro and in vivo, although the percentage of fragments made in vitro is greater than that in vivo. The percentage of total Z gene-encoded protein which is found as fragments is estimated to be roughly 23% in vivo. This means that about 31% of the total number of β-galactosidase monomers synthesized are prematurely terminated molecules. The average molecular weight of the polypeptides produced is 91,000. This corresponds to a termination event occurring on the average once every 3200 codons. The sites at which termination occurs appear to be specific and are located primarily near the 3′-end of the gene.Polypeptides synthesized in vitro and in vivo from templates containing mutations in the Z gene have also been compared. Most of the mutationally generated fragments synthesized in vitro are stable, unlike their in vivo counterparts, which are often rapidly degraded. One fragment, however, generated by an early amber mutation in the Z gene, is degraded in the in vitro system. The mechanism of degradation appears to be specific for small abnormal polypeptides. Internal reinitiation polypeptides generated by nonsense mutations, which have been found in vivo, are not detected in the in vitro protein synthesis system under the conditions used here.     

Advances in molecular epidemiology of cryptosporidiosis in dogs and cats

The use of molecular tools has led to the identification of several zoonotic Cryptosporidium spp. in dogs and cats. Among them, Cryptosporidium canis and Cryptosporidium felis are dominant species causing canine and feline cryptosporidiosis, respectively. Some Cryptosporidium parvum infections have also been identified in both groups of animals. The identification of C. canis, C. felis and C. parvum in both pets and owners suggests the possible occurrence of zoonotic transmission of Cryptosporidium spp. between humans and pets. However, few cases of such concurrent infections have been reported. Thus, the cross-species transmission of Cryptosporidium spp. between dogs or cats and humans has long been a controversial issue. Recently developed subtyping tools for C. canis and C. felis should be very useful in identification of zoonotic transmission of both Cryptosporidium spp. Data generated using these tools have confirmed the occurrence of zoonotic transmission of these two Cryptosporidium spp. between owners and their pets, but have also shown the potential presence of host-adapted subtypes. Extensive usage of these subtyping tools in epidemiological studies of human cryptosporidiosis is needed for improved understanding of the importance of zoonotic transmission of Cryptosporidium spp. from pets.     

Diverse Mesorhizobium bacteria nodulate native Astragalus and Oxytropis in arctic and subarctic areas in Eurasia

Rhizobia nodulating native Astragalus and Oxytropis spp. in Northern Europe are not well-studied. In this study, we isolated bacteria from nodules of four Astragalus spp. and two Oxytropis spp. from the arctic and subarctic regions of Sweden and Russia. The phylogenetic analyses were performed by using sequences of three housekeeping genes (16S rRNA, rpoB and recA) and two accessory genes (nodC and nifH). The results of our multilocus sequence analysis (MLSA) of the three housekeeping genes tree showed that all the 13 isolates belonged to the genus Mesorhizobium and were positioned in six clades. Our concatenated housekeeping gene tree also suggested that the isolates nodulating Astragalus inopinatus, Astragalus frigidus, Astragalus alpinus ssp. alpinus and Oxytropis revoluta might be designated as four new Mesorhizobium species. The 13 isolates were grouped in three clades in the nodC and nifH trees. ¹⁵N analysis suggested that the legumes in association with these isolates were actively fixing nitrogen.     

Bacterial communities in water and sediment shaped by paper mill pollution and indicated bacterial taxa in sediment in Daling River

Effluents from paper mills are highly toxic and are a major source of aquatic pollution. In this study, we collected water and sediment samples to examine the microbial communities using denaturing gradient gel electrophoresis and identified bacterial taxa greatly affected by paper mill pollution using next-generation sequencing data. Our results indicated that bacterial communities in downstream sediments were similar to those in paper mill discharge sites, indicating obvious effects of pollution, while bacterial communities in downstream water samples showed similar profiles to those in upstream sites, both being quite different from the bacterial communities in paper mill discharge sites. This was possibly because of the short contact period. In addition, bacterial communities in the estuary were quite different from those in other water and sediment samples, which was owing to the special habitat type. Considering the storage of paper mill pollutants in sediment and the significant effect on shifts in bacterial communities, we selected Clostridia and Epsilonproteobacteria at the class level and Fusibacter and Desulfobulbus at the genus level as bacterial indicators of paper mill pollution. To monitor the remediation of polluted aquatic environments, we propose Sphingobacteria, Alphaproteobacteria, Actinobacteria, Subdivision3, Planctomycetacia and Verrucomicrobiae at the class level and Bacillus, Steroidobacter, Nocardioides, Terrimonas, Pirellula and Methylibium at the genus level.     

Agroinfiltration and PVX Agroinfection in Potato and Nicotiana benthamiana

Agroinfiltration and PVX agroinfection are two efficient transient expression assays for functional analysis of candidate genes in plants. The most commonly used agent for agroinfiltration is Agrobacterium tumefaciens, a pathogen of many dicot plant species. This implies that agroinfiltration can be applied to many plant species. Here, we present our protocols and expected results when applying these methods to the potato (Solanum tuberosum), its related wild tuber-bearing Solanum species (Solanum section Petota) and the model plant Nicotiana benthamiana. In addition to functional analysis of single genes, such as resistance (R) or avirulence (Avr) genes, the agroinfiltration assay is very suitable for recapitulating the R-AVR interactions associated with specific host pathogen interactions by simply delivering R and Avr transgenes into the same cell. However, some plant genotypes can raise nonspecific defense responses to Agrobacterium, as we observed for example for several potato genotypes. Compared to agroinfiltration, detection of AVR activity with PVX agroinfection is more sensitive, more high-throughput in functional screens and less sensitive to nonspecific defense responses to Agrobacterium. However, nonspecific defense to PVX can occur and there is a risk to miss responses due to virus-induced extreme resistance. Despite such limitations, in our experience, agroinfiltration and PVX agroinfection are both suitable and complementary assays that can be used simultaneously to confirm each other''s results.     

Diversity of Babesia and Theileria species in symptomatic and asymptomatic dogs in Croatia

Babesiosis, the disease caused by tick-borne hematozoan parasites of the genus Babesia, is particularly common in dogs, and is caused by several “large” species of Babesia, as well as by an increasing number of “small” species of Babesia, some of which appear to be more closely related to members of the genus Theileria. In this work, blood samples were collected from 848 randomly selected, asymptomatic dogs and from 81 symptomatic dogs, microscopically positive for Babesia, and characterised by PCR and sequence analysis of a fragment of the ssrRNA gene. A prevalence of 3.42% (29 of 848) was found in asymptomatic dogs and sequence analysis revealed the presence of Babesia canis canis in 20 dogs (69%), Babesia gibsoni in six dogs (21%), Babesia canis vogeli in two dogs (7%) and Theileria annae in one dog (3%). In the group of symptomatic dogs, which were all positive by PCR, B. canis canis was the predominant species (78 dogs, or 96%), followed by single infections with B. canis vogeli, Babesia caballi and Theileria equi. Our study has confirmed that dogs are infected with a wide range of both large and small piroplasm species and subspecies, including B. caballi and T. equi, two parasites usually found in horses. The detection of the pathogenic species B. canis canis and B. gibsoni in asymptomatic dogs indicates that the relationship between parasite species/subspecies and clinical signs of infection in dogs deserves further investigation. Finally, the identities of the tick vectors transmitting T. annae and B. caballi remain to be elucidated.     

Occurrence of Choline and Glycine Betaine Uptake and Metabolism in the Family Rhizobiaceae and Their Roles in Osmoprotection

The role of glycine betaine and choline in osmoprotection of various Rhizobium, Sinorhizobium, Mesorhizobium, Agrobacterium, and Bradyrhizobium reference strains which display a large variation in salt tolerance was investigated. When externally provided, both compounds enhanced the growth of Rhizobium tropici, Sinorhizobium meliloti, Sinorhizobium fredii, Rhizobium galegae, Agrobacterium tumefaciens, Mesorhizobium loti, and Mesorhizobium huakuii, demonstrating their utilization as osmoprotectants. However, both compounds were inefficient for the most salt-sensitive strains, such as Rhizobium leguminosarum (all biovars), Agrobacterium rhizogenes, Rhizobium etli, and Bradyrhizobium japonicum. Except for B. japonicum, all strains exhibit transport activity for glycine betaine and choline. When the medium osmolarity was raised, choline uptake activity was inhibited, whereas glycine betaine uptake was either increased in R. leguminosarum and S. meliloti or, more surprisingly, reduced in R. tropici, S. fredii, and M. loti. The transport of glycine betaine was increased by growing the cells in the presence of the substrate. With the exception of B. japonicum, all strains were able to use glycine betaine and choline as sole carbon and nitrogen sources. This catabolic function, reported for only a few soil bacteria, could increase competitiveness of rhizobial species in the rhizosphere. Choline dehydrogenase and betaine-aldehyde dehydrogenase activities were present in the cells of all strains with the exception of M. huakuii and B. japonicum. The main physiological role of glycine betaine in the family Rhizobiaceae seems to be as an energy source, while its contribution to osmoprotection is restricted to certain strains.     

Drought- and ABA-Induced Changes in Polypeptide and mRNA Accumulation in Tomato Leaves

Drought stress triggers abscisic acid (ABA) biosynthesis resulting in ABA accumulation. The ABA-deficient tomato mutant, flacca (Lycopersicon esculentum Mill. cv Ailsa Craig), does not synthesize ABA in response to drought stress. This mutant has been used to distinguish polypeptides and in vitro translation products that are synthesized during drought stress in response to elevated ABA levels from those that are induced directly by altered water relations. A set of polypeptides and in vitro translation products was synthesized during drought stress in the wild type. These polypeptides and in vitro translation products were synthesized to a lesser extent in the drought-stressed ABA-deficient mutant. Treatment of flacca with ABA resulted in the synthesis of the drought-stress-induced polypeptides and in vitro translation products. These results support the hypothesis that many of the polypeptides that are synthesized during drought are regulated by alterations in ABA concentration. Similarly, the mRNA population was altered by ABA during drought stress.     

Differential Adherence and Expression of Virulence Traits by Candida albicans and Candida parapsilosis in Mono- and Dual-Species Cultures in Artificial Saliva

Aims

To evaluate specific virulence factors of Candida albicans and Candida parapsilosis clinical oral isolates in mono- and dual-species culture in the presence of artificial saliva.

Methods and Results

Two of the strains used in this study were isolated from co-infection (C. albicans AM and C. parapsilosis AM2), and the other two were isolated from single infection (C. albicans AC and C. parapsilosis AD). The number of adhered yeast cells was measured and their enzymatic activity was determined simultaneously. In mono-species culture, C. parapsilosis strains adhered to a higher extent to the surface in comparison with the C. albicans strains. In dual-species culture, the C. parapsilosis strains adhered more in the presence of C. albicans AM. Interestingly, C. albicans AM and C. parapsilosis AD adhered to a higher extent when compared with all other co-cultures. In dual-species culture, the enzymatic activity of C. parapsilosis strains in the presence of C. albicans AC was higher than in the presence of C. albicans AM.

Conclusions

The virulence factors of C. albicans and C. parapsilosis differ from strain to strain and are influenced by the presence of other species in culture.

Significance and Impact of the Study

To understand the expression of virulence factors in Candida dual-species systems.