Salicylic acid-independent plant defence pathways

Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are independent of salicylic acid. Evidence is emerging that jasmonic acid and ethylene play key roles in these salicylic acid-independent pathways. Cross-talk between the salicylic acid-dependent and the salicylic acid-independent pathways provides great regulatory potential for activating multiple resistance mechanisms in varying combinations.     

Androgen receptor status predicts response to chemotherapy, not risk of breast cancer in Indian women

Voltage gated potassium channels have been extensively studied in relation to cancer. In this review, we will focus on the role of two potassium channels, Ether à-go-go (Eag), Human ether à-go-go related gene (HERG), in cancer and their potential therapeutic utility in the treatment of cancer. Eag and HERG are expressed in cancers of various organs and have been implicated in cell cycle progression and proliferation of cancer cells. Inhibition of these channels has been shown to reduce proliferation both in vitro and vivo studies identifying potassium channel modulators as putative inhibitors of tumour progression. Eag channels in view of their restricted expression in normal tissue may emerge as novel tumour biomarkers.     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

<Emphasis Type="Italic">Arabidopsis</Emphasis> ETO1 specifically interacts with and negatively regulates type 2 1-aminocyclopropane-1-carboxylate synthases

Background  

In Arabidopsis, ETO1 (ETHYLENE-OVERPRODUCER1) is a negative regulator of ethylene evolution by interacting with AtACS5, an isoform of the rate-limiting enzyme, 1-aminocyclopropane-1-carboxylate synthases (ACC synthase or ACS), in ethylene biosynthetic pathway. ETO1 directly inhibits the enzymatic activity of AtACS5. In addition, a specific interaction between ETO1 and AtCUL3, a constituent of a new type of E3 ubiquitin ligase complex, suggests the molecular mechanism in promoting AtACS5 degradation by the proteasome-dependent pathway. Because orthologous sequences to ETO1 are found in many plant species including tomato, we transformed tomato with Arabidopsis ETO1 to evaluate its ability to suppress ethylene production in tomato fruits.     

Clinical features and predictors for disease natural progression in adults with Pompe disease: a nationwide prospective observational study

Background

Due partly to physicians’ unawareness, many adults with Pompe disease are diagnosed with great delay. Besides, it is not well known which factors influence the rate of disease progression, and thus disease outcome. We delineated the specific clinical features of Pompe disease in adults, and mapped out the distribution and severity of muscle weakness, and the sequence of involvement of the individual muscle groups. Furthermore, we defined the natural disease course and identified prognostic factors for disease progression.

Methods

We conducted a single-center, prospective, observational study. Muscle strength (manual muscle testing, and hand-held dynamometry), muscle function (quick motor function test), and pulmonary function (forced vital capacity in sitting and supine positions) were assessed every 3–6 months and analyzed using repeated-measures ANOVA.

Results

Between October 2004 and August 2009, 94 patients aged between 25 and 75 years were included in the study. Although skeletal muscle weakness was typically distributed in a limb-girdle pattern, many patients had unfamiliar features such as ptosis (23%), bulbar weakness (28%), and scapular winging (33%). During follow-up (average 1.6 years, range 0.5-4.2 years), skeletal muscle strength deteriorated significantly (mean declines of ?1.3% point/year for manual muscle testing and of ?2.6% points/year for hand-held dynamometry; both p<0.001). Longer disease duration (>15 years) and pulmonary involvement (forced vital capacity in sitting position <80%) at study entry predicted faster decline. On average, forced vital capacity in supine position deteriorated by 1.3% points per year (p=0.02). Decline in pulmonary function was consistent across subgroups. Ten percent of patients declined unexpectedly fast.

Conclusions

Recognizing patterns of common and less familiar characteristics in adults with Pompe disease facilitates timely diagnosis. Longer disease duration and reduced pulmonary function stand out as predictors of rapid disease progression, and aid in deciding whether to initiate enzyme replacement therapy, or when.

     

Self-assembling diblock copolymers of poly[N-(2-hydroxypropyl)methacrylamide] and a beta-sheet peptide

The self-assembly of hybrid diblock copolymers composed of poly(HPMA) and beta-sheet peptide P11 (CH(3)CO-QQRFQWQFEQQ-NH(2)) blocks was investigated. Copolymers were synthesized via thiol-maleimide coupling reaction, by conjugation of semitelechelic poly(HPMA)-SH with maleimide-modified beta-sheet peptide. As expected, CD and CR binding studies showed that the peptide block imposed its beta-sheet structural arrangement on the structure of diblock copolymers. TEM and AFM proved that peptide and these copolymers had the ability to self-assemble into fibrils.     

Gene structure,transcripts and calciotropic effects of the PTH family of peptides in <Emphasis Type="Italic">Xenopus</Emphasis> and chicken

Background  

Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) belong to a family of endocrine factors that share a highly conserved N-terminal region (amino acids 1-34) and play key roles in calcium homeostasis, bone formation and skeletal development. Recently, PTH-like peptide (PTH-L) was identified in teleost fish raising questions about the evolution of these proteins. Although PTH and PTHrP have been intensively studied in mammals their function in other vertebrates is poorly documented. Amphibians and birds occupy unique phylogenetic positions, the former at the transition of aquatic to terrestrial life and the latter at the transition to homeothermy. Moreover, both organisms have characteristics indicative of a complex system in calcium regulation. This study investigated PTH family evolution in vertebrates with special emphasis on Xenopus and chicken.     

The dystonia gene THAP1 controls DNA double-strand break repair choice

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Pronounced Effect of the Nature of the Inoculum on Biofilm Development in Flow Systems

Biofilm formation renders sessile microbial populations growing in continuous-flow systems less susceptible to variation in dilution rate than planktonic cells, where dilution rates exceeding an organism''s maximum growth rate (μ_max) results in planktonic cell washout. In biofilm-dominated systems, the biofilm''s overall μ_max may therefore be more relevant than the organism''s μ_max, where the biofilm μ_max is considered as a net process dependent on the adsorption rate, growth rate, and removal rate of cells within the biofilm. Together with lag (acclimation) time, the biofilm''s overall μ_max is important wherever biofilm growth is a dominant form, from clinical settings, where the aim is to prevent transition from lag to exponential growth, to industrial bioreactors, where the aim is to shorten the lag and rapidly reach maximum activity. The purpose of this study was to measure CO₂ production as an indicator of biofilm activity to determine the effect of nutrient type and concentration and of the origin of the inoculum on the length of the lag phase, biofilm μ_max, and steady-state metabolic activity of Pseudomonas aeruginosa PA01 (containing gfp), Pseudomonas fluorescens CT07 (containing gfp), and a mixed community. As expected, for different microorganisms the lengths of the lag phase in biofilm development and the biofilm μ_max values differ, whereas different nutrient concentrations result in differences in the lengths of lag phase and steady-state values but not in biofilm μ_max rates. The data further showed that inocula from different phenotypic origins give rise to lag time of different lengths and that this influence persists for a number of generations after inoculation.Microbial growth in batch cultures has been studied for a long time, and the observed phases have been designated the lag phase, the acceleration phase, the exponential phase, the retardation phase, the stationary phase, and the phase of decline although not each culture displays all of the mentioned phases (16). In contrast to batch cultures and static (no flow) biofilms (e.g., those that form in 96-well plates), the increase in biofilm cells in a flowing environment is a net process that is dependent on the irreversible adsorption rate of cells to the surface, the growth rate of the microorganisms, and the removal rate of cells lost to the bulk flow (18). There are numerous benefits for the cells in biofilms, e.g., protection against antimicrobials and the opportunity for and proliferation by continuous cell dispersion. There is also a possible competitive advantage if cells colonize surfaces at multiple sites and grow in such a manner that the resulting three-dimensional architecture exposes the maximum biofilm surface area to surrounding nutrients. The most successful colonizers would therefore be the cells with the ability to adhere to the surface (and stay adhered) and to start multiplying at maximum rate. The process of events from being free-floating cells to the so-called permanently surface-attached phase involves early steps including reversible attachment and a phenotypic change in the cells from a planktonic state to a sessile state, with concomitant changes in gene expression; these steps contribute to a lag phase that will occur before maximal growth/biofilm development can take place (23). Clearly, the ability to progress from the lag phase to a fast-growing phase, as well as the duration of the lag phase, is an important determinant of biofilm function and has an impact in a diverse range of environments, often with implications for infection or contamination control, as well as in industrial processes.At the cell level, an extended lag phase and slower growth create the risk that the cells will be displaced by faster-growing microcolonies, as was demonstrated by Klayman et al. (13) in dual species biofilms. A microorganism''s competence in dominating a surface area can therefore be evaluated by comparing the lag phases and maximal growth rates (μ_max) of a biofilm growth curve. Knowing a bacterial population''s specific growth rate is a requirement for its cultivation at optimum rates in a chemostat or other continuously fed bioreactor. A key assumption for this type of cultivation is that wall growth has a negligible effect, which is in stark contrast to systems where surface-associated growth dominates. Indeed, while dilution rates exceeding an organism''s μ_max results in cell washout in a conventional chemostat setting, biofilm formation enables microbial populations to persist at dilution rates much higher than the organism''s μ_max.Biofilm growth rates have been determined by various techniques, such as fluorescence in situ hybridization (FISH) (12, 31), measuring the incorporation of radioactive substances like [³H]thymidine and ³²P (8, 9), microscopy (3, 13, 17), measuring the total increase in biofilm mass (both cells and extracellular polymeric substances) (24, 28), colorimetric 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenyl-amino)carbonyl]-2H- tetrazolium hydroxide (XTT) assays (26), or measurement of amide II bands, as determined by attenuated total reflectance-Fourier transform infrared spectroscopy (6). Some of the above-mentioned techniques suffer the drawback that the biofilms have to be sacrificed with sampling or that the measured increases do not distinguish between live and dead matter in the biofilm (i.e., increases measured might not represent an accurate increase in viable cell numbers).In this study a carbon dioxide evolution measurement system (CEMS) (15) was used to track the biofilm development rate in real time. The advantage of using this system is that the measured rates represent the metabolic activity of the active cell mass and can be done nondestructively for any biofilm-forming microorganism. In the past, measurement of oxygen uptake rates has been used for determination of growth rates in batch cultures (19) and of the localized growth rate in biofilms (32). CO₂ measurements by a gas chromatograph have been used to determine growth rates in batch systems (4), but to our knowledge this is the first time that CO₂ measurements have been used to determine whole-biofilm specific growth rates. We applied this technique to compare the biofilm μ_max values for two well-described pseudomonads and a mixed microbial community when the organisms are grown on different nutrients and to test the premise that the origin of the inoculum has an impact on early biofilm development.