PSII photochemistry in vegetative buds and needles of Norway spruce (Picea abies L. Karst.) probed by OJIP chlorophyll a fluorescence measurement

Vegetative buds represent developmental stage of Norway spruce (Picea abies L. Karst.) needles where chloroplast biogenesis and photosynthetic activity begin. We used the analyses of polyphasic chlorophyll a fluorescence rise (OJIP) to compare photosystem II (PSII) functioning in vegetative buds and fully photosynthetically active mature current-year needles. Considerably decreased performance index (PIABS) in vegetative buds compared to needles pointed to their low photosynthetic efficiency. Maximum quantum yield of PSII (Fv/Fm) in buds was slightly decreased but above limited value for functionality indicating that primary photochemistry of PSII is not holdback of vegetative buds photosynthetic activity. The most significant difference observed between investigated developmental stages was accumulation of reduced primary quinine acceptor of PSII (QA-) in vegetative buds, as a result of its limited re-oxidation by passing electrons to secondary quinone acceptor, QB. We suggest that reduced electron transfer from QA- to QB could be the major limiting factor of photosynthesis in vegetative buds.     

In Silico Analysis for Determination and Validation of Iron-Regulated Protein from Escherichia coli

International Journal of Peptide Research and Therapeutics - The iron ion is an essential element in biological processes. Many of biological activities in cells, such as peroxide reduction,...     

Nordic Walking improves daily physical activities in COPD: a randomised controlled trial

Background

In patients with COPD progressive dyspnoea leads to a sedentary lifestyle. To date, no studies exist investigating the effects of Nordic Walking in patients with COPD. Therefore, the aim was to determine the feasibility of Nordic Walking in COPD patients at different disease stages. Furthermore we aimed to determine the short- and long-term effects of Nordic Walking on COPD patients'' daily physical activity pattern as well as on patients exercise capacity.

Methods

Sixty COPD patients were randomised to either Nordic Walking or to a control group. Patients of the Nordic Walking group (n = 30; age: 62 ± 9 years; FEV₁: 48 ± 19% predicted) underwent a three-month outdoor Nordic Walking exercise program consisting of one hour walking at 75% of their initial maximum heart rate three times per week, whereas controls had no exercise intervention. Primary endpoint: daily physical activities (measured by a validated tri-axial accelerometer); secondary endpoint: functional exercise capacity (measured by the six-minute walking distance; 6MWD). Assessment time points in both groups: baseline, after three, six and nine months.

Results

After three month training period, in the Nordic Walking group time spent walking and standing as well as intensity of walking increased (Δ walking time: +14.9 ± 1.9 min/day; Δ standing time: +129 ± 26 min/day; Δ movement intensity: +0.40 ± 0.14 m/s²) while time spent sitting decreased (Δ sitting time: -128 ± 15 min/day) compared to baseline (all: p < 0.01) as well as compared to controls (all: p < 0.01). Furthermore, 6MWD significantly increased compared to baseline (Δ 6MWD: +79 ± 28 meters) as well as compared to controls (both: p < 0.01). These significant improvements were sustained six and nine months after baseline. In contrast, controls showed unchanged daily physical activities and 6MWD compared to baseline for all time points.

Conclusions

Nordic Walking is a feasible, simple and effective physical training modality in COPD. In addition, Nordic Walking has proven to positively impact the daily physical activity pattern of COPD patients under short- and long-term observation.

Clinical trial registration

Nordic Walking improves daily physical activities in COPD: a randomised controlled trial - ISRCTN31525632     

Help Seeking Behavior of Women with Self-Discovered Breast Cancer Symptoms: A Meta-Ethnographic Synthesis of Patient Delay

Background and Objective

Patient delay makes a critical contribution to late diagnosis and poor survival in cases of breast cancer. Identifying the factors that influence patient delay could provide information for adopting strategies that shorten this delay. The aim of this meta-ethnography was to synthesize existing qualitative evidence in order to gain a new understanding of help seeking behavior in women with self-discovered breast cancer symptoms and to determine the factors that influence patient delay.

Methods

The design was a meta-ethnography approach. A systematic search of the articles was performed in different databases including Elsevier, PubMed, ProQuest and SCOPUS. Qualitative studies with a focus on help seeking behaviors in women with self-discovered breast cancer symptoms and patient delay, published in the English language between 1990 and 2013 were included. The quality appraisal of the articles was carried out using the Critical Appraisal Skills Programme qualitative research checklist and 13 articles met the inclusion criteria. The synthesis was conducted according to Noblit and Hare’s meta-ethnographic approach (1988), through reciprocal translational analysis and lines-of-argument.

Findings

The synthesis led to identification of eight repeated key concepts including: symptom detection, initial symptom interpretation, symptom monitoring, social interaction, emotional reaction, priority of medical help, appraisal of health services and personal-environmental factors. Symptom interpretation is identified as the important step of the help seeking process and which changed across the process through active monitoring of their symptoms, social interactions and emotional reactions. The perceived seriousness of the situation, priority to receive medical attention, perceived inaccessibility and unacceptability of the health care system influenced women’s decision-making about utilizing health services.

Conclusion

Help seeking processes are influenced by multiple factors. Educational programs aimed at correcting misunderstandings, erroneous social beliefs and improving self-awareness could provide key strategies to improve health policy which would reduce patient delay.     

Histopathology of roots of Glycine max (L.) Merrill induced by root-knot nematode (Meloidogyne incognita)

In Glycine max, the second-stage juveniles of Meloidogyne incognita entered the roots through the apical meristem or elongation zone. The juveniles induced giant cells in the zone of vascular strands. Near the head of the nematode and adjacent to the giant cells, the vascular strands exhibited abnormalities in their shapes and structures; both xylem and phloem were found to be affected. The giant cells had dense and granular cytoplasm, and large nuclei with large nucleoli. Some parenchyma cells exhibited hypertrophy, while others exhibited hyperplasia. The distinctive feature of the study is reporting the occurrence of abnormal xylem, abnormal phloem and abnormal parenchyma.     

Effect of different inoculum levels of Meloidogyne incognita on growth and yield of Lycopersicon esculentum,and internal structure of infected root

Lycopersicon esculentum (tomato) plants, grown in sterilised clay pots, were inoculated with 50, 500, 1000, and 3000 second-stage juveniles (J2) of the root-knot nematode (Meloidogyne incognita) and were kept in a greenhouse. A non-significant reduction in plant growth and yield was noticed in T1 plants. Significant reductions in plant growth and yield were found in T2, T3, and T4 plants. Highest reductions, in growth and yield, were observed in T5 plants. Transverse and longitudinal sections revealed that M. incognita traversed through the cortical tissues of the root, caused infection in the differentiating vascular tissues and successfully established in the infected roots. The post-infection changes in the affected parts were hypertrophy and hyperplasia, around the head of the nematodes. Five to 10, among the hypertrophied cells, developed into very large, multinucleate, prominent, and highly specialised giant cells. The nuclei in each giant cell enclosed one or more nucleoli. Xylem and the phloem strands were found to be disoriented. Abnormal xylem and phloem comprised a substantial portion near the giant cells. The metabolic changes in the affected part led to the formation of galls, characteristic of the root-knot infection.     

<Emphasis Type="Italic">In Vitro</Emphasis> Characterization and Evaluation of the Cytotoxicity Effects of Nisin and Nisin-Loaded PLA-PEG-PLA Nanoparticles on Gastrointestinal (AGS and KYSE-30), Hepatic (HepG2) and Blood (K562) Cancer Cell Lines

The aim of this study was an in vitro evaluation and comparison of the cytotoxic effects of free nisin and nisin-loaded PLA-PEG-PLA nanoparticles on gastrointestinal (AGS and KYSE-30), hepatic (HepG2), and blood (K562) cancer cell lines. To create this novel anti-cancer drug delivery system, the nanoparticles were synthesized and then loaded with nisin. Subsequently, their biocompatibility, ability to enter cells, and physicochemical properties, including formation, size, and shape, were studied using hemolysis, fluorescein isothiocyanate (FITC), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM), respectively. Then, its loading efficiency and release kinetics were examined to assess the potential impact of this formulation for the nanoparticle carrier candidacy. The cytotoxicities of nisin and nisin-loaded nanoparticles were evaluated by using the MTT and Neutral Red (NR) uptake assays. Detections of the apoptotic cells were done via Ethidium Bromide (EB)/Acridine Orange (AO) staining. The FTIR spectra, SEM images, and DLS graph confirmed the formations of the nanoparticles and nisin-loaded nanoparticles with spherical, distinct, and smooth surfaces and average sizes of 100 and 200 nm, respectively. The loading efficiency of the latter nanoparticles was about 85–90%. The hemolysis test represented their non-cytotoxicities and the FITC images indicated their entrance inside the cells. An increase in the percentage of apoptotic cells was observed through EB/AO staining. These results demonstrated that nisin had a cytotoxic effect on AGS, KYSE-30, HepG2, and K562 cancer cell lines, while the cytotoxicity of nisin-loaded nanoparticles was more than that of the free nisin.     

Comparative Analysis of Super-Shedder Strains of Escherichia coli O157:H7 Reveals Distinctive Genomic Features and a Strongly Aggregative Adherent Phenotype on Bovine Rectoanal Junction Squamous Epithelial Cells

Shiga toxin-producing Escherichia coli O157:H7 (O157) are significant foodborne pathogens and pose a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ). Some colonized animals, referred to as “super-shedders” (SS), are known to shed O157 in exceptionally large numbers (>104 CFU/g of feces). Recent studies suggest that SS cattle play a major role in the prevalence and transmission of O157, but little is known about the molecular mechanisms associated with super-shedding. Whole genome sequence analysis of an SS O157 strain (SS17) revealed a genome of 5,523,849 bp chromosome with 5,430 open reading frames and two plasmids, pO157 and pSS17, of 94,645 bp and 37,446 bp, respectively. Comparative analyses showed that SS17 is clustered with spinach-associated O157 outbreak strains, and belongs to the lineage I/II, clade 8, D group, and genotype 1, a subgroup of O157 with predicted hyper-virulence. A large number of non-synonymous SNPs and other polymorphisms were identified in SS17 as compared with other O157 strains (EC4115, EDL933, Sakai, TW14359), including in key adherence- and virulence-related loci. Phenotypic analyses revealed a distinctive and strongly adherent aggregative phenotype of SS17 on bovine RAJ stratified squamous epithelial (RSE) cells that was conserved amongst other SS isolates. Molecular genetic and functional analyses of defined mutants of SS17 suggested that the strongly adherent aggregative phenotype amongst SS isolates is LEE-independent, and likely results from a novel mechanism. Taken together, our study provides a rational framework for investigating the molecular mechanisms associated with SS, and strong evidence that SS O157 isolates have distinctive features and use a LEE-independent mechanism for hyper-adherence to bovine rectal epithelial cells.     

Chlorophyll a fluorescence during flag leaf senescence of field-grown winter wheat plants under drought conditions

Improving wheat grain yield plays a significant role in ensuring global food security. Wheat production could be increased by the genetic improvement of wheat genotypes where delayed senescence with enhanced post-anthesis capacity and staygreen traits could have an important role. In this study, chlorophyll a fluorescence (ChlF) rise kinetics from the early until late senescence of flag leaves, grain yield and other agro-morphological characteristics were compared for three winter wheat advanced lines (Osk.4.312/10-18, Osk.4.330/6-18 and Osk.4.354/12-18) under natural drought conditions. The differences between lines were observed when considering the heading date which was 1 and 4 days earlier for the line Osk.4.354/12-18, than lines Osk.4.312/10-18 and Osk.4.330/6-18, respectively. Furthermore, line Osk.4.354/12-18 had the highest test weight (kg hl⁻¹), while line Osk.4.330/6-18 showed a tendency of decreased grain yield, compared to the other two lines. Analysis of ChlF transients and several JIP-test parameters indicated that all three lines had a generally similar course of changes in the photosynthetic performance of flag leaves during senescence under drought conditions. However, at the point when a decrease in photosynthetic performance was initiated, it was slightly less intensive in line Osk.4.354/12-18 accompanied by longer preservation of functionality and connectivity of PSII units, than in the other two lines, which contributed to its better agronomical performance. These results indicated that even delicate variations in the functioning of the photosynthetic apparatus of the flag leaf during grain filling were agronomically important, especially when plants were exposed to drought stress, and could be used to differentiate otherwise similar wheat genotypes. Even small genotype-specific differences in the photosynthetic performance of senescing flag leaves, along with earlier heading dates, could assist in the selection of genotypes with a better ability to cope with unfavourable environmental conditions.