Measuring salinity

Non-Peer ReviewedRoot-zone salinity reduces crop yields. The extent of the reduction depends on the kinds and concentrations of salts existing in the soil solutions across the field. The salts which cause root-zone salinity typically dissociate into sodium, calcium, magnesium, and sometimes potassium cations together with chloride, sulphate, bicarbonate, and carbonate anions. These ions, when dissolved in soil water and concentrated in excess of plant needs, can disrupt crop water uptake and plant metabolism. We easily recognize the existence of salinity when we see white salt crusts on soil surfaces. But, root-zone salinity may also exist in field locations which never show white crusting. Surveying and mapping a field using geo-physical instruments operating on the soil surface can reveal this hidden root-zone salinity. Although measurements with these instruments are affected by soil texture, chemistry, water-content, temperature, and other factors, basic indices can still be calculated by linking survey measurements with detailed salinity values derived from soil cores extracted as part of the survey

Coexistence of Trichome Variation in a Natural Plant Population: A Combined Study Using Ecological and Candidate Gene Approaches

The coexistence of distinct phenotypes within populations has long been investigated in evolutionary ecology. Recent studies have identified the genetic basis of distinct phenotypes, but it is poorly understood how the variation in candidate loci is maintained in natural environments. In this study, we examined fitness consequences and genetic basis of variation in trichome production in a natural population of Arabidopsis halleri subsp. gemmifera. Half of the individuals in the study population produced trichomes while the other half were glabrous, and the leaf beetle Phaedon brassicae imposed intensive damage to both phenotypes. The fitness of hairy and glabrous plants showed no significant differences in the field during two years. A similar result was obtained when sibling hairy and glabrous plants were transplanted at the same field site, whereas a fitness cost of trichome production was detected under a weak herbivory condition. Thus, equivalent fitness of hairy and glabrous plants under natural herbivory allows their coexistence in the contemporary population. The pattern of polymorphism of the candidate trichome gene GLABROUS1 (GL1) showed no evidence of long-term maintenance of trichome variation within the population. Although balancing selection under fluctuating biotic environments is often proposed to explain the maintenance of defense variation, the lack of clear evidence of balancing selection in the study population suggests that other factors such as gene flow and neutral process may have played relatively large roles in shaping trichome variation at least for the single population level

The bc 1 complexes of Rhodobacter sphaeroides and Rhodobacter capsulatus

Photosynthetic bacteria offer excellent experimental opportunities to explore both the structure and function of the ubiquinol-cytochrome c oxidoreductase ( bc 1 complex). In both Rhodobacter sphaeroides and Rhodobacter capsulatus , the bc 1 complex functions in both the aerobic respiratory chain and as an essential component of the photosynthetic electron transport chain. Because the bc 1 complex in these organisms can be functionally coupled to the photosynthetic reaction center, flash photolysis can be used to study electron flow through the enzyme and to examine the effects of various amino acid substitutions. During the past several years, numerous mutations have been generated in the cytochrome b subunit, in the Rieske iron-sulfur subunit, and in the cytochrome c 1 subunit. Both site-directed and random mutagenesis procedures have been utilized. Studies of these mutations have identified amino acid residues that are metal ligands, as well as those residues that are at or near either the quinol oxidase (Q o ) site or the quinol reductase (Q i ) site. The postulate that these two Q-sites are located on opposite sides of the membrane is supported by these studies. Current research is directed at exploring the details of the catalytic mechanism, the nature of the subunit interactions, and the assembly of this enzyme.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44795/1/10863_2004_Article_BF00762582.pd

Managing multimorbidity in primary care in patients with chronic respiratory conditions

The term multimorbidity is usually defined as the coexistence of two or more chronic conditions within an individual, whereas the term comorbidity traditionally describes patients with an index condition and one or more additional conditions. Multimorbidity of chronic conditions markedly worsens outcomes in patients, increases treatment burden and increases health service costs. Although patients with chronic respiratory disease often have physical comorbidities, they also commonly experience psychological problems such as depression and anxiety. Multimorbidity is associated with increased health-care utilisation and specifically with an increased number of prescription drugs in individuals with multiple chronic conditions such as chronic obstructive pulmonary disease. This npj Primary Care Respiratory Medicine Education Section case study involves a patient in a primary care consultation presenting several common diseases prevalent in people of this age. The patient takes nine different drugs at this moment, one or more pills for each condition, which amounts to polypharmacy. The problems related with polypharmacy recommend that a routine medication review by primary care physicians be performed to reduce the risk of adverse effects of polypharmacy among those with multiple chronic conditions. The primary care physician has the challenging role of integrating all of the clinical problems affecting the patient and reviewing all medicaments (including over-the-counter medications) taken by the patient at any point in time, and has the has the key to prevent the unwanted consequences of polypharmacy. Multimorbid chronic disease management can be achieved with the use of care planning, unified disease templates, use of information technology with appointment reminders and with the help of the wider primary care and community teams