The role of iron in nodulation and nitrogen fixation in Lupinus angustifolius L

The effects of iron concentration in solution on nodulation and symbiotic N2 fixation in lupins (Lupinus angustifolius L. ev. Yandee) were studied in solution culture in the glasshouse by comparing plants supplied with NH4NO3 with those reliant on N2 fixation. At very low iron supply, adding NH4NO2 did not increase shoot growth. Under moderate iron deficiency, where plants were pale green, adding NH4NO3 increased shoot growth, implying that moderate iron deficiency was, operationally, nitrogen deficiency. Higher iron concentrations in solution were required for maximum growth of plants reliant on symbiotic N2 fixation than for those supplied with NH4NO3 Iron deficiency depressed nodule initiation earlier than host plant growth, resulting in decreased nodule number and mass. Alleviating iron deficiency enhanced leghaemoglobin production in nodules and increased nitrogen concentrations in the shoots. Iron concentration in the youngest fully expanded leaves provided a good indication of the severity of iron deficiency‐caused chlorosis. The results suggest that iron is involved in symbiotic N2 fixation through effects on both nodule initiation and nodule function, and that the symbiosis has a higher iron requirement than that needed for host plant growth

Which stage of nodule initiation in Lupinus angustifolius L. is sensitive to iron deficiency?

Transfer experiments in solution culture were conducted to establish the stage of nodulation in lupins (Lupinus angustifolius L. cv. Yandee) most sensitive to iron deficiency. In all experiments, iron deficiency had a much greater effect on nodule number than on host plant growth. Irrespective of the iron treatment of either the Bradyrhizobium or the lupin plant prior to inoculation, plants receiving 2.5 μM iron after inoculation successfully formed nodule initials and nodules while those receiving 0.05 μM iron almost completely failed to initiate nodules. Thus, the prevention of nodulation by iron deficiency is not a consequence of either an inadequate number of infective bradyrhizobia surviving in the solution or an alteration in the iron status of the host root. Supply of 2.5 μM iron for 4 d or more after inoculation produced a similar number of nodule initials and nodules as did continuous supply of 2.5 μMiron. Delaying supply of 2.5 μM iron for 3 d or less after inoculation did not delay or prevent nodule initiation and formation. One‐day exposure of plants to 2.5μM iron on day 4 after inoculation induced the highest number of nodules of any 1 d treatment although this short exposure was not enough to allow the full complement of nodules to form. Hence, the impairment of the nodulation process by iron deficiency can be attributed to the prevention of a step at day 4, the stage just before nodule initials are formed. A further study was conducted to examine the effect of iron on nodule formation by using a vertical split‐root technique in which Bradyrhizobium sp. (Lupinus) was added to the upper compartment. Compared to plants receiving 0.05 μM iron in both compartments, plants receiving 0.05 μM in the upper and 5 5 μM iron in the lower compartments had only a slightly higher concentration of iron in the cortex of the upper part of the root. Furthermore, supplying 5 μM iron to the lower part of a root did not permit nodulation on the upper part of the root receiving 0.05 μMiron. Low concentration of iron in the cortex of roots may limit nodule formation

On the isomorphism problem of concept algebras

Weakly dicomplemented lattices are bounded lattices equipped with two unary operations to encode a negation on {\it concepts}. They have been introduced to capture the equational theory of concept algebras \cite{Wi00}. They generalize Boolean algebras. Concept algebras are concept lattices, thus complete lattices, with a weak negation and a weak opposition. A special case of the representation problem for weakly dicomplemented lattices, posed in \cite{Kw04}, is whether complete {\wdl}s are isomorphic to concept algebras. In this contribution we give a negative answer to this question (Theorem \ref{T:main}). We also provide a new proof of a well known result due to M.H. Stone \cite{St36}, saying that {\em each Boolean algebra is a field of sets} (Corollary \ref{C:Stone}). Before these, we prove that the boundedness condition on the initial definition of {\wdl}s (Definition \ref{D:wdl}) is superfluous (Theorem \ref{T:wcl}, see also \cite{Kw09}).Comment: 15 page

Aetiological role of viral and bacterial infections in acute adult lower respiratory tract infection (LRTI) in primary care.

BACKGROUND: Lower respiratory tract infections (LRTI) are a common reason for consulting general practitioners (GPs). In most cases the aetiology is unknown, yet most result in an antibiotic prescription. The aetiology of LRTI was investigated in a prospective controlled study. METHODS: Eighty adults presenting to GPs with acute LRTI were recruited together with 49 controls over 12 months. Throat swabs, nasal aspirates (patients and controls), and sputum (patients) were obtained and polymerase chain reaction (PCR) and reverse transcriptase polymerase chain reaction (RT-PCR) assays were used to detect Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila, influenza viruses (AH1, AH3 and B), parainfluenza viruses 1-3, coronaviruses, respiratory syncytial virus, adenoviruses, rhinoviruses, and enteroviruses. Standard sputum bacteriology was also performed. Outcome was recorded at a follow up visit. RESULTS: Potential pathogens were identified in 55 patients with LRTI (69%) and seven controls (14%; p<0.0001). The identification rate was 63% (viruses) and 26% (bacteria) for patients and 12% (p<0.0001) and 6% (p = 0.013), respectively, for controls. The most common organisms identified in the patients were rhinoviruses (33%), influenza viruses (24%), and Streptococcus pneumoniae (19%) compared with 2% (p<0.001), 6% (p = 0.013), and 4% (p = 0.034), respectively, in controls. Multiple pathogens were identified in 18 of the 80 LRTI patients (22.5%) and in two of the 49 controls (4%; p = 0.011). Atypical organisms were rarely identified. Cases with bacterial aetiology were clinically indistinguishable from those with viral aetiology. CONCLUSION: Patients presenting to GPs with acute adult LRTI predominantly have a viral illness which is most commonly caused by rhinoviruses and influenza viruses

Remarks on the Central Limit Theorem for Non-Convex Bodies

In this note, we study possible extensions of the Central Limit Theorem for non-convex bodies. First, we prove a Berry-Esseen type theorem for a certain class of unconditional bodies that are not necessarily convex. Then, we consider a widely-known class of non-convex bodies, the so-called p-convex bodies, and construct a counter-example for this class

On reducing the complexity of matrix clocks

Matrix clocks are a generalization of the notion of vector clocks that allows the local representation of causal precedence to reach into an asynchronous distributed computation's past with depth $x$, where $x\ge 1$ is an integer. Maintaining matrix clocks correctly in a system of $n$ nodes requires that everymessage be accompanied by $O(n^x)$ numbers, which reflects an exponential dependency of the complexity of matrix clocks upon the desired depth $x$. We introduce a novel type of matrix clock, one that requires only $nx$ numbers to be attached to each message while maintaining what for many applications may be the most significant portion of the information that the original matrix clock carries. In order to illustrate the new clock's applicability, we demonstrate its use in the monitoring of certain resource-sharing computations

PACE-IT study protocol: a stepped wedge cluster randomised controlled trial evaluating the implementation of telehealth visual assessment in emergency care for people living in residential aged-care facilities.

BACKGROUND:Transfer of residential aged-care facility (RACF) residents to Emergency Departments (ED) is common, risky and expensive. RACF residents who present to ED are more likely to have hospital readmissions, longer stays and face major risks related to hospital acquired complications. Aged Care Emergency services (ACE) is a nurse led, protocol- guided, telephone RACF/ED outreach model that has been shown to be effective in reducing hospitalisation and length of hospital stay for RACF residents in the Hunter New England Local Health District, New South Wales (NSW). The Partnerships in Aged-Care Emergency services using Interactive Telehealth (PACE-IT) project enhances ACE by incorporating interactive video assessment and consultation. The PACE-IT project's primary aim is to assess whether augmentation of ACE services through the addition of protocol-guided interactive Visual Telehealth Consultation (VTC) for clinical decision-making, plus telephone follow-up, reduces RACF resident transfers to ED. METHODS:A stepped-wedge cluster randomised controlled trial will be conducted. The intervention will be delivered sequentially to 8 clusters; each cluster comprises one ED and two RACFs in NSW, Australia. The 16 RACFs in the study will be selected for order of implementation using a computer-generated randomisation sequence. A 2-step randomisation process will be undertaken, randomising the hospital EDs first and then randomising the RACFs aligned with each hospital. The PACE-IT intervention comprises: an initial phone call by RACFs to the ACE service in the ED; the ACE service in ED responds with a protocol-guided VTC, a management plan agreed between all participants; an automated consultation summary letter to the General Practitioner and the RACF; a post VTC 24 h follow-up phone call to the RACF. DISCUSSION:If shown to be effective, the intervention has the potential to improve the clinical care and quality of life for residents. Findings will provide high level evidence that will inform sustainable change and broad translation into practice across NSW. It will show how the change has been achieved and highlight success factors for scalability and sustainability. It will inform review of processes, the development of policy and guidelines that will integrate PACE-IT into existing service models in NSW. TRIAL REGISTRATION:The trial is registered with the Australian New Zealand Clinical Trials Registry (Trial ID ACTR N12619001692123 ) 02/12/2020.)

The Bromodomains of the mammalian SWI/SNF (mSWI/SNF) ATPases Brahma (BRM) and Brahma Related Gene 1 (BRG1) promote chromatin interaction and are critical for skeletal muscle differentiation

Skeletal muscle regeneration is mediated by myoblasts that undergo epigenomic changes to establish the gene expression program of differentiated myofibers. mSWI/SNF chromatin remodeling enzymes coordinate with lineage-determining transcription factors to establish the epigenome of differentiated myofibers. Bromodomains bind to acetylated lysines on histone N-terminal tails and other proteins. The mutually exclusive ATPases of mSWI/SNF complexes, BRG1 and BRM, contain bromodomains with undefined functional importance in skeletal muscle differentiation. Pharmacological inhibition of mSWI/SNF bromodomain function using the small molecule PFI-3 reduced differentiation in cell culture and in vivo through decreased myogenic gene expression, while increasing cell cycle-related gene expression and the number of cells remaining in the cell cycle. Comparative gene expression analysis with data from myoblasts depleted of BRG1 or BRM showed that bromodomain function was required for a subset of BRG1- and BRM-dependent gene expression. Reduced binding of BRG1 and BRM after PFI-3 treatment showed that the bromodomain is required for stable chromatin binding at target gene promoters to alter gene expression. Our findings demonstrate that mSWI/SNF ATPase bromodomains permit stable binding of the mSWI/SNF ATPases to promoters required for cell cycle exit and establishment of muscle-specific gene expression