Cryopreservation of <Emphasis Type=Italic>Robinia</Emphasis><Emphasis Type=Italic>pseudoacacia</Emphasis>

Cryopreservation of Robinia pseudoacacia explants by vitrification achieved 78% survival following the stepwise preculture of shoot tips in (0.3 + 0.5 + 0.7 M) sucrose with a 80 min incubation in PVS2; compared to 87% survival after desiccation of explants to 30% water content, following 3 days alginate bead (with glycerol and sucrose treatments) preculture in 0.7 M sucrose.     

Attenuation of fibrosis <Emphasis Type=Italic>in vitro</Emphasis> and <Emphasis Type=Italic>in vivo</Emphasis> with <Emphasis Type=Italic>SPARC</Emphasis> siRNA

Introduction  

SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs.     

Efficient separation and purification of allophycocyanin from <Emphasis Type=Italic>Spirulina</Emphasis> (<Emphasis Type=Italic>Arthrospira</Emphasis>) <Emphasis Type=Italic>platensis</Emphasis>

Allophycocyanin (APC) is a minor component of phycobiliproteins in cyanobacteria and red algae. This paper describes a simple and inexpensive extracting method for isolating APC from Spirulina (Arthrospira) platensis with high efficiency. The crude phycobiliprotein extract was pretreated by ammonium sulfate fractionation. Then, by adding hydroxylapatite into crude phycobiliprotein extract dissolved in 20 mM phosphate buffer (pH 7.0), APC was selectively adsorbed by hydroxylapatite but C-phycocyanin (C-PC) was not. The hydroxylapatite was collected and APC was extracted from the crude phycobiliprotein extract. Then, the enriched APC was washed off from the hydroxylapatite using 100 mM phosphate buffer (pH 7.0). In this simple extracting method it was easy to remove C-PC and isolate APC in large amounts. The absorbance ratio A ₆₅₀/A ₂₈₀ of extracted APC reached 2.0. The recovery yield was 70%, representing 4.61 mg · g⁻¹ wet weight. The extracted APC could be further purified by a simple anion-exchange chromatography with a pH gradient from 5.6 to 4.0. The absorbance ratio A ₆₅₀/A ₂₈₀ of the purified APC reached 5.0, and the overall recovery yield was 43%, representing 2.83 mg · g⁻¹ wet weight. Its purity was confirmed by native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE.     

<Emphasis Type=Italic>In vitro</Emphasis> organogenesis of <Emphasis Type=Italic>Passiflora alata</Emphasis>

Passiflora alata in vitro organogenesis was studied based on explant type, culture medium composition, and incubation conditions. The results indicated that the morphogenic process occurred more efficiently when hypocotyl segment-derived explants were cultured in media supplemented with cytokinin and AgNO₃ incubated under a 16-h photoperiod. The shoot bud elongation and plant development were obtained by transferring the material to MSM culture medium supplemented with GA₃ and incubated in flasks with vented lids. Histological analyses of the process revealed that the difficulties in obtaining plants could be related to the development of protuberances and leaf primordia structures, which did not contain shoot apical meristem. Roots developed easily by transferring elongated shoots to 1/2 MSM culture medium. Plant acclimatization occurred successfully, and somaclonal variation was not visually detected. The efficiency of this organogenesis protocol will be evaluated for genetic transformation of this species to obtain transgenic plants expressing genes that can influence the resistance to Cowpea aphid borne mosaic virus.     

Interaction of <Emphasis Type=Italic>Bdellovibrio bacteriovorus</Emphasis> with bacteria <Emphasis Type=Italic>Campylobacter jejuni</Emphasis> and <Emphasis Type=Italic>Helicobacter pylori</Emphasis>

Interaction of Bdellovibrio bacteriovorus 100NCJB with bacteria Campylobacter jejuni (strains 1, 2, 3, 4, and 5) and Helicobacter pylori, strain TX30a, was confirmed. The results indicate that lytic activity of bdellovibrios both in liquid media and cells attached to a surface was observed. The potential use of the antimicrobial activity of predatory bacteria for environmental bioprotection and public health is discussed.     

Probiotic <Emphasis Type=Italic>Lactobacillus</Emphasis> strains: <Emphasis Type=Italic>in vitro</Emphasis> and <Emphasis Type=Italic>in vivo</Emphasis> studies

Three Lactobacillus strains (LOCK 0900, LOCK 0908, LOCK 0919) out of twenty-four isolates were selected according to their antagonistic activity against pathogenic bacteria, resistance to low pH and milieu of bile salts. Intragastric administration of a mixture of these strains to Balb/c mice affected cytokine T_H1-T_H2 balance toward nonallergic T_H1 response. Spleen cells, isolated from lactobacilli-treated mice and re-stimulated in vitro with the mixture of heat-inactivated tested strains, produced significantly higher amounts of anti-allergic tumor necrosis factor- and interferon-γ than control animals whereas the level of pro-allergic interleukin-5 was significantly lower. Lactobacillus cells did not translocate through the intestinal barrier into blood, liver and spleen; a few Lactobacillus cells found in mesenteric lymph nodes could create antigenic reservoir activating the immune system. The mixture of Lactobacillus LOCK 0900, LOCK 0908 and LOCK 0919 strains represents a probiotic bacterial preparation with possible use in prophylaxis and/or therapy of allergic diseases.     

<Emphasis Type=Italic>Pseudomonas aeruginosa</Emphasis> inhibits <Emphasis Type=Italic>in-vitro Candida</Emphasis> biofilm development

Background  

Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development.     

Regulation of the <Emphasis Type=Italic>ALBINO3</Emphasis>-mediated transition to flowering in <Emphasis Type=Italic>Arabidopsis</Emphasis> depends on the expression of <Emphasis Type=Italic>CO</Emphasis> and <Emphasis Type=Italic>GA1</Emphasis>

ALBINO3, a homologue of PPF1 in Arabidopsis, encodes a chloroplast protein, and is essential for chloroplast differentiation. In the present study, ALBINO3(−) transgenic plants exhibited a significant decrease in both the number of rosette leaves at bolting and the days before bolting, suggesting the important roles of ALBINO3 in regulating flowering during non-inductive short-day photoperiods. ALBINO3 mRNA was apparently accumulated in shoot apical meristem and floral meristems around the shoot apical meristem in wild-type plants. ALBINO3 might be predominantly involved in inducing the floral repression pathway by activating the expression of TFL1, and by suppressing the expression of LFY, respectively, in the shoot apical meristem. Moreover, the function of ALBINO3 in regulating flowering transition depended on the expression of CO and GA1, because ALBINO3 might function in the downstream integration of the photoperiod-dependent and the photoperiod-independent pathways. These results suggest that ALBINO3 may have an important integrative function in the flowering process in Arabidopsis.     

Chytrid infection reduces thoracic beat and heart rate of <Emphasis Type=Italic>Daphnia</Emphasis><Emphasis Type=Italic>pulicaria</Emphasis>

Zooplankters are hosts to numerous endo- and ectoparasites, some of which have dramatic impacts on their hosts. Epizootics on zooplankton are probably more widespread in lake systems than it is currently known, and few studies have explored the direct and indirect importance of parasitism in aquatic food webs. In addition, our understanding of the sublethal effects of parasitic infections on host organisms and populations is limited. We used a novel electro-chemical based technique to measure in the outflow of the feeding current changes in the beat rate of the thoracic appendages in female Daphnia pulicaria. We observed simultaneously the heart rates and compared chytrid infected animals with uninfected gravid and non-gravid ones. We found in uninfected animals a thoracic beat rate of 3.81 ± 018 Hz and a heart rate of 4.67 ± 0.42 Hz. Gravid daphnids had a 14% lower thoracic beat rate (3.27 ± 0.30 Hz) than non-gravid females while the heart rate did not significantly differ (4.48 ± 0.28 Hz). In contrast, infected animals showed a 22% lower thoracic beat rate (2.96 ± 0.47 Hz) and a 36% lower heart rate (2.98 ± 0.5 Hz) when compared with uninfected non-gravid females. We discuss the ways Daphnia are affected by Polycaryum leave infections on the individual and population level.     

Functional analysis of <Emphasis Type=Italic>Xa3/Xa26</Emphasis> family members in rice resistance to <Emphasis Type=Italic>Xanthomonas</Emphasis><Emphasis Type=Italic>oryzae</Emphasis> pv. <Emphasis Type=Italic>oryzae</Emphasis>

Plant disease resistant (R) genes are frequently clustered in the genome. The diversity of members in a complex R-gene family may provide variation in resistance specificity. Rice Xa3/Xa26, conferring resistance to Xanthomonas oryzae pv. oryzae (Xoo) encodes a leucine-rich repeat (LRR) receptor kinase-type protein and belongs to a multigene family, consisting of Xa3/Xa26, MRKa, MRKc and MRKd in rice cultivar Minghui 63. MRKa and MRKc are intact genes, while MRKd is a pseudogene. Complementary analyses showed that MRKa and MRKc could not mediate resistance to Xoo when regulated by their native promoters, but MRKa not MRKc conferred partial resistance to Xoo when regulated by a strong constitutive promoter. Plants carrying truncated XA3/XA26, which lacked the kinase domain, were compromised in their resistance to Xoo. However, the kinase domain of MRKa could partially restore the function of the truncated XA3/XA26 in resistance. MRKa and MRKc showed similar expression pattern as Xa3/Xa26, which expressed only in the vascular systems of different tissues. The expressional characteristic of MRKa and MRKc perfectly fits the function of genes conferring resistance to Xoo, a vascular pathogen. These results suggest that although MRKa and MRKc cannot mediate bacterial blight resistance nowadays, they may be once effective genes for Xoo resistance. Their expressional characteristic and sequence similarity to Xa3/Xa26 will provide templates for generating novel recognition specificity to face the evolution of Xoo. In addition, both LRR and kinase domains encoded by Xa3/Xa26 and MRKa are the functional determinants and MRKa-mediated resistance is dosage-dependent. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Identification of nitrogen-fixing <Emphasis Type=Italic>Paenibacillus</Emphasis> from different plant rhizospheres and a novel <Emphasis Type=Italic>nifH</Emphasis> gene detected in the <Emphasis Type=Italic>P. stellifer</Emphasis>

A total of 534 isolates were selectively obtained from different plant rhizospheres based on their growth on nitrogen-free medium and their resistance to 80°C for 15 min. Of the 534 isolates, 23 isolates had nifH gene and exhibited nitrogenase activities. Based on 16S rDNA sequence, G + C content assay and DNA-DNA hybridization, the 23 isolates which divided into four monophyletic clusters were all belonged to the Paenibacillus genus. nifH gene deduced amino acid alignment aLnalysis revealed that cluster I, including 15 isolates, showed the highest NifH identity with Paenibacillus genus; while cluster II identified as P. stellifer by DNA-DNA hybridization was consistent with four uncultured bacterial clones. This study suggested that the nitrogen-fixing Paenibacillus were distributed in various ecosystems and prevalent in different plant rhizospheres. It was the first demonstration that nitrogen fixation existed in P. jamilae and P. stellifer. In eight isolates identified as P. stellifer species, a novel nifH gene was detected in Paenibacillus.     

Control of pyrimidine nucleotide formation in <Emphasis Type=Italic>Pseudomonas</Emphasis><Emphasis Type=Italic>fulva</Emphasis>

Control of pyrimidine formation was examined in Pseudomonas fulva ATCC 31418. Pyrimidine supplementation lowered pyrimidine biosynthetic pathway enzyme activities in cells grown on glucose or succinate as a carbon source indicating possible repression of enzyme synthesis. Pyrimidine limitation experiments were conducted using an orotidine 5′-monophosphate decarboxylase mutant strain isolated in this study. Compared to uracil-supplemented, glucose-grown mutant cells, pyrimidine limitation of this strain caused aspartate transcarbamoylase, dihydroorotase, dihydroorotate dehydrogenase and orotate phosphoribosyltransferase activities to increase about 6-, 13-, 3-, 15-fold, respectively, which confirmed regulation of enzyme synthesis by pyrimidines. At the level of enzyme activity, transcarbamoylase activity in Ps. fulva was strongly inhibited by pyrophosphate, CTP, GTP and GDP under saturating substrate concentrations.     

Karyotype analysis of medicinal plant <Emphasis Type=Italic>Liriope spicata</Emphasis> var. <Emphasis Type=Italic>prolifera</Emphasis> (Liliaceae)

Karyotype of Liriope spicata var. prolifera, a Chinese endemic species, was described in detail for the first time. Its proto-variety L. spicata was also investigated for comparison. The basic chromosome number of these two species was x = 18. L. spicata var. prolifera, recorded as triploid 2n = 54, consisted of 30 metacentric chromosomes and 24 submetacentric chromosomes. Only one chromosome of the 11th group had a secondary constriction with a satellite in the short arm. L. Spicata was tetraploid 2n = 72 and consisted of four sets of 6 submetacentric chromosomes and 12 metacentric chromosomes without visible satellites. This paper provides further available data on Liriope chromosomes, and also indicates that L. spicata var. prolifera and L. spicata are probably separate species.     

Multiplex quantitative PCR for detection of lower respiratory tract infection and meningitis caused by <Emphasis Type=Italic>Streptococcus pneumoniae</Emphasis>, <Emphasis Type=Italic>Haemophilus influenzae</Emphasis> and <Emphasis Type=Italic>Neisseria meningitidis</Emphasis>

Background  

Streptococcus pneumoniae and Haemophilus influenzae cause pneumonia and as Neisseria meningitidis they are important agents of meningitis. Although several PCR methods have been described for these bacteria the specificity is an underestimated problem. Here we present a quantitative multiplex real-time PCR (qmPCR) for detection of S. pneumoniae (9802 gene fragment), H. influenzae (omp P6 gene) and N. meningitidis (ctrA gene). The method was evaluated on bronchoalveolar lavage (BAL) samples from 156 adults with lower respiratory tract infection (LRTI) and 31 controls, and on 87 cerebrospinal fluid (CSF) samples from meningitis patients.     

Remobilization of <Emphasis Type=Italic>Tol2</Emphasis> transposons in <Emphasis Type=Italic>Xenopus tropicalis</Emphasis>

Background  

The Class II DNA transposons are mobile genetic elements that move DNA sequence from one position in the genome to another. We have previously demonstrated that the naturally occurring Tol2 element from Oryzias latipes efficiently integrates its corresponding non-autonomous transposable element into the genome of the diploid frog, Xenopus tropicalis. Tol2 transposons are stable in the frog genome and are transmitted to the offspring at the expected Mendelian frequency.