Search

Background: Sex differences in the longitudinal relationship between dynapenic abdominal obesity, i.e., impairment in muscle strength and high waist circumference, and disability in activities of daily living have not been investigated to date. Therefore, we aimed to examine sex differences in the longitudinal association between dynapenic abdominal obesity at baseline and the onset of disability in activities of daily living during a four-year follow-up period among Irish adults aged ≥50 years., Methods: Data from Wave 1 (2009-2011) and Wave 3 (2014-2015) of the Irish Longitudinal Study on Ageing survey were analyzed. Dynapenia was defined as handgrip strength of <26 kg for men and <16 kg for women. Abdominal obesity was defined as waist circumference of >88 cm for women and >102 cm for men. Dynapenic abdominal obesity was defined as having both dynapenia and abdominal obesity. Disability was defined as having difficulty with at least one of six activities of daily living (dressing, walking, bathing, eating, getting in or out of bed, using the toilet). Multivariable logistic regression was conducted to assess associations., Results: Data on 4471 individuals aged ≥50 years and free of disability at baseline were analyzed [mean (SD) age 62.3 (8.6) years; 48.3 % males]. In the overall sample, compared to no dynapenia and no abdominal obesity, dynapenic abdominal obesity was associated with 2.15 (95%CI = 1.17-3.93) times higher odds for incident disability at 4-year follow-up. This association was significant among men (OR = 3.78; 95%CI = 1.70-8.38) but not among women (OR = 1.34; 95%CI = 0.60-2.98)., Conclusions: Interventions to prevent or address dynapenic abdominal obesity may aid in the prevention of disability, especially among men., Competing Interests: Declaration of competing interest The authors declare that they have no competing interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Six strains of Rhizobium trifolii were exposed to specific bacteriophages and the properties of 10 surviving clones of each studied. Two temperate bacteriophages produced clones which were lysogenic but showed no changes in colony form, symbiotic properties, or somatic antigens. Of forty clones selected by exposure to four other bacteriophages, none were lysogenic although there was some indication of unusually long association of phage with bacteria in infected cultures. Seventeen of these clones were changed in symbiotic properties, 15 in colony morphology, and 13 in somatic cross-reaction with the parent. Unexpectedly, despite stringent selection conditions, 28 were still either partially or completely susceptible to the selecting phage.

The effect of the lytic phage LPP-DUN1 on the cyanobacterium Plectonema boryanum has been investigated in batch and in continuous cultures in the presence and absence of silt. In batch culture Plectonema without added phage grew normally; the presence of phage caused rapid lysis of the cyanobacterium and the addition of silt prevented lysis by the phage. In continuous culture the numbers of cyanobacterial cells and phage particles oscillated in a reciprocal manner, but the addition of silt damped down the oscillations in Plectonema biomass without decreasing the numbers of phage particles isolated from the cultures. The presence of silt thus appears to protect the cyanobacterium from lysis by phage, although the total numbers of phage particles are relatively unaffected by the silt, at least in the short-term.

The effect of rhizobiophages CT3 and CT4 on Rhizobium trifolii SU91 and SU36, respectively, was examined. These phage-susceptible strains were used, either singly or paired with a competing phage-resistant type as inoculum for Trifolium subterraneum plants growing in vitro in agar medium. Addition of bacteriophage to single strain experiments produced no significant effects on total bacterial numbers, nodulation, or plant dry weight. However, when phages were added to the paired inocula, significant decreases in counts of the susceptible strain were observed, frequently accompanied by a rise in numbers of the resistnt type. An increase in the proportion of ineffective variants of the susceptible rhizobia was also observed, although plant dry weights and nodule numbers were not altered. These effects were dependent only upon a difference in phage susceptibility of the bacteria and were obtained even when the competing strain was only partially resistant and a relativly poor competitor.

Enzymes induced by two Rhizobium trifolii bacteriophages caused depolymerization of exopolysaccharides from most R. trifolii and R. leguminosarum strains tested, but did not, in general, attack the exopolysaccharides of R. meliloti, the slow-growing rhizobia, or Agrobacterium. Ca2+ and (or) Mg2+ were required for enzyme activity. In all strains tested, depolymerization of exopolysaccharide occurred when there was successful phage infection, but depolymerization also occurred with exopolysaccharides from nonsusceptible strains.

Fluctuations in numbers of Rhizobium leguminosarum biovar trifolii and its bacteriophages in two fields with different soil types were followed during a 17-month period in 1981 and 1982. Mean levels of both phage and rhizobia varied significantly (P < 0.05) on different occasions, with rhizobial levels varying from 1.6 x 10 to 2.0 x 10 cell per g of soil and phage from 0 to 1.7 x 10 PFU/g of soil. Multivariate regression analysis showed rhizobial levels to be significantly and positively related to vegetation height and solar radiation, but not to mean temperature, precipitation, soil matric potential, or soil type. Rhizobiophage concentrations were significantly and positively related to soil matric potential and vegetation height. They were reduced in the silty clay loam soil, although the presence of 34% clay did not prevent phage multiplication and the occurrence of high phage levels.