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Increased stocking rates under typical pasture improvement practices in southern Australia have often been associated with low persistence by sown perennial grasses subjected to continuous stocking. Cultivars of the perennial grass phalaris ( Phalaris aquatica L.), which is widely used in southern Australia, vary in their phenology and growth habit. Winter-active cultivars have also been developed with improved stress tolerances, viz. heavy grazing pressure (Holdfast GT) and acid soils (Advanced AT). This study examined the persistence of phalaris genotypes over 4 years under five management treatments: high P-high stocking rate (18 sheep per hectare) rotationally stocked ( HPRS); high P-high stocking rate continuously stocked ( HPCS); high P-intermediate stocking rate (13·5 sheep per hectare) continuously stocked (HPCS13.5); low P-low stocking rate (9 sheep per hectare) rotationally stocked ( LPRS); and low P-low stocking rate continuously stocked ( LPCS). Basal frequency of phalaris declined rapidly under HPCS and LPCS in the first year of treatments when periods of low herbage mass occurred under low rainfall. Basal frequency in high P treatments stabilized and partially recovered but continued to decline in low P treatments. Holdfast GT survived the early decline in the HPCS treatment better than other winter-active cultivars and similar to a known grazing tolerant, semi-winter-dormant cultivar. Advanced AT and older winter-active cultivars were sensitive to continuous stocking but persisted better under rotational stocking or under a reduced rate of continuous stocking ( HPCS13.5). Rotational management clearly promoted persistence of winter-active phalaris, but long-term persistence will be better ensured by combining management with the use of genotypes with grazing tolerance traits. [ABSTRACT FROM AUTHOR]

Rytidosperma species (formerly Austrodanthonia) are native grasses common in temperate grasslands of southern Australia. Nine Rytidosperma species, Lolium perenne and Bromus hordeaceus were grown as microswards in pots in a glasshouse, and their growth response to six levels of applied P was measured. Shoot yield differed up to twofold between the highest- and lowest-yielding Rytidosperma species. Some Rytidosperma species were slow growing with minimal ability to respond to increased soil P availability. However, three species, Rytidosperma duttonianum, Rytidosperma racemosum and Rytidosperma richardsonii, had a similar shoot yield to L. perenne. Species that grew well at high P also grew well at low P, except B. hordeaceus, which was the lowest-yielding species at low P, but had among the highest yields at high P. No species showed evidence of P toxicity. The species exhibited a range in critical external P requirement (i.e. amount of P applied for 90% maximum yield). Among the fast-growing Rytidosperma species, R. richardsonii was notable because it had a low critical external P (16·3 mg P pot−1) and high agronomic P-use efficiency (94·1 g DW g−1 P applied). In contrast, R. duttonianum had a higher critical external P requirement (22·4 mg P pot−1) and lower agronomic P-use efficiency (85 g DW g−1 P applied). It was concluded that it is important to know which Rytidosperma species are present in a grassland to understand how it may respond to P fertilization. The results help to explain the diverse opinions expressed about the productivity of pastures containing Rytidosperma species. [ABSTRACT FROM AUTHOR]

ABSTRACT We present a new catalogue of 5106 infrared bubbles created through visual classification via the online citizen science website 'The Milky Way Project'. Bubbles in the new catalogue have been independently measured by at least five individuals, producing consensus parameters for their position, radius, thickness, eccentricity and position angle. Citizen scientists - volunteers recruited online and taking part in this research - have independently rediscovered the locations of at least 86 per cent of three widely used catalogues of bubbles and H ii regions whilst finding an order of magnitude more objects. 29 per cent of the Milky Way Project catalogue bubbles lie on the rim of a larger bubble, or have smaller bubbles located within them, opening up the possibility of better statistical studies of triggered star formation. Also outlined is the creation of a 'heat map' of star formation activity in the Galactic plane. This online resource provides a crowd-sourced map of bubbles and arcs in the Milky Way, and will enable better statistical analysis of Galactic star formation sites. [ABSTRACT FROM AUTHOR]

Field-based plant bioassays were employed to assess the potential for pre- and post-emergence loss of seedlings and for root damage affecting Trifolium subterraneum L. (subterranean clover) during autumn-winter at 17 pasture sites across a broad agricultural area of temperate southern Australia. Between 9 and 93% (median 21%) of T. subterranean seedlings failed to emerge at the 14 locations where soil moisture was considered adequate for germination. Post-emergence losses were lower (range 0-32%; median 7%). Moderate damage (lateral roots) to severe damage (taproots) was recorded on surviving test plants at all of the sites. Sublethal damage to pasture roots constitutes a potentially large, but underestimated cost to production because it was so widespread and because the damage occurs during autumn-winter when pasture yield limits stocking rate. Potential for the loss of Lolium rigidum × multiflorum (annual ryegrass) seedlings was also demonstrated at some of the sites. DNA assays for common root rot disease pathogens ( Pythium irregulare, Phytopthora clandestina and Rhizoctonia) were used for the first time to construct cost-effective profiles of fungal and oomycete pathogens at each site. These assays may be useful for indicating disease risks and guiding plant cultivar selection and appropriate use of pesticides. DNA assays for arbuscular mycorrhizal fungi were also used and have the potential to provide novel insights into the soil biology of farming systems. [ABSTRACT FROM AUTHOR]

ABSTRACT We propose an evolutionary path for pre-stellar cores on the radius-mass diagram, which is analogous to stellar evolutionary paths on the Hertzsprung-Russell diagram. Using James Clerk Maxwell Telescope (JCMT) observations of L1688 in the Ophiuchus star-forming complex, we analyse the HCO+ ( J= 4 → 3) spectral line profiles of pre-stellar cores. We find that of the 58 cores observed, 14 show signs of infall in the form of a blue-asymmetric double-peaked line profile. These 14 cores all lie beyond the Jeans mass line for the region on a radius-mass plot. Furthermore, another 10 cores showing tentative signs of infall, in their spectral line profile shapes, appear on or just over the Jeans mass line. We therefore propose the manner in which a pre-stellar core evolves across this diagram. We hypothesize that a core is formed in the low-mass, low-radius region of the plot. It then accretes quasi-statically, increasing in both mass and radius. When it crosses the limit of gravitational instability, it begins to collapse, decreasing in radius, towards the region of the diagram where protostellar cores are seen. [ABSTRACT FROM AUTHOR]

We reanalyse all of the archived observations of the Ophiuchus dark cloud L1688 that were carried out with the submillimetre common-user bolometer array on the James Clerk Maxwell Telescope. For the first time, we put together all the data that were taken of this cloud at different times to make a deeper map at 850 μm than has ever been published. Using this new, deeper map, we extract the pre-stellar cores from the data. We use updated values for the distance to the cloud complex, and also for the internal temperatures of the pre-stellar cores to generate an updated core mass function (CMF). This updated CMF is consistent with previous results in so far as they went, but our deeper map gives an improved completeness limit of (0.16 Jy), which enables us to show that a turnover exists in the low-mass regime of the CMF. The L1688 CMF shows the same form as the stellar initial mass function (IMF), and can be mapped on to the stellar IMF, showing that the IMF is determined at the pre-stellar core stage. We compare L1688 with the Orion star-forming region and find that the turnover in the L1688 CMF occurs at a mass roughly a factor of 2 lower than the CMF turnover in Orion. This suggests that the position of the CMF turnover may be a function of environment. [ABSTRACT FROM AUTHOR]

The root morphology of ten temperate pasture species (four annual grasses, four perennial grasses and two annual dicots) was compared and their responses to P and N deficiency were characterised. Root morphologies differed markedly; some species had relatively fine and extensive root systems ( Vulpia spp., Holcus lanatus L. and Lolium rigidum Gaudin), whilst others had relatively thick and small root systems ( Trifolium subterraneum L. and Phalaris aquatica L.). Most species increased the proportion of dry matter allocated to the root system at low P and N, compared with that at optimal nutrient supply. Most species also decreased root diameter and increased specific root length in response to P deficiency. Only some of the species responded to N deficiency in this way. Root morphology was important for the acquisition of P, a nutrient for which supply to the plant depends on root exploration of soil and on diffusion to the root surface. Species with fine, extensive root systems had low external P requirements for maximum growth and those with thick, small root systems generally had high external P requirements. These intrinsic root characteristics were more important determinants of P requirement than changes in root morphology in response to P deficiency. Species with different N requirements could not be distinguished clearly by their root morphological attributes or their response to N deficiency, presumably because mass flow is relatively more important for N supply to roots in soil. [ABSTRACT FROM AUTHOR]

Intron 3 and the flanking exons of the calmodulin gene have been amplified, cloned, and sequenced from 18 members of the gastropod genus Littorina. From the 48 sequences, at least five different gene copies have been identified and their functionality characterized using a strategy based upon the potential protein product predicted from flanking exon data. The functionality analyses suggest that four of the genes code for functional copies of calmodulin. All five copies have been identified across a wide range of littorinid species although not ubiquitously. Using this novel approach based on intron sequences, we have identified an unprecedented number of potential calmodulin copies in Littorina, exceeding that reported for any other invertebrate. This suggests a higher number of, and more ancient, gene duplications than previously detected in a single genus. [ABSTRACT FROM AUTHOR]

Five fructan exohydrolase activities from Lolium rigidum Gaudin were separated and partly purified by a combination of salt precipitation, affinity chromatography, gel-filtration chromatography, anion-exchange chromatography and isoelectric focusing. The activities were identified by incubating enzyme fractions with fructan from both Lolium rigidum and Cichorium intybus. On the basis of activities when (6,6,6)-kestopentaose and (1,1,1)-kestopentaose were used as substrates, it was concluded that three of the activities hydrolyzed β-2,6-glycosidic linkages faster than β-2,1-glycosidic linkages and two activities hydrolyzed β-2,1-glycosidic linkages faster than β-2,6-glycosidic linkages. Fructan exohydrolases that hydrolyze β-2,1-glycosidic linkages faster than β-2,6-glycosidic linkages, and fructan exohydrolases that hydrolyze β-2,6-glycusidic linkages faster than β-2,1-glycosidic linkages have not previously been identified together in a temperate grass. All fructan exohydrolases were inhibited markedly by sucrose. It is proposed that the classification of β-fructofuranosidases be reconsidered because EC 3 . 2 . 1 . 80 is presently used to designate all fructan exohydrolases irrespective of the rates at which they hydrolyze β-2,1- or β-2,6-glycosidic linkages in fructans. [ABSTRACT FROM AUTHOR]

Fructan- and sucrose-hydrolyzing activity was extracted from plants of Lolium rigidum Gaudin. Sucrose-hydrolyzing activity varied 30-fold between different plant parts and parts of different ages. In contrast, fructan-hydrolyzing activity only varied two-fold. At least four β-fructofuranosidase activities were partially purified from mature vegetative tissues of Lolium rigidum. The β-fructofuranosidases were characterized by their different elution patterns on various chromatographic media and their relative rates of hydrolysis of sucrose and fructan extracted from different sources. Fructan-hydrolyzing activities were partially purified that hydrolyzed fructan containing predominantly 2-1 glycosidic linkages relatively more rapidly than fructan containing predominantly 2-6 glycosidic linkages. β-fructofuranosidases that were relatively more active against fructan than sucrose when compared with activity present in the crude extract, were inhibited by sucrose. It is concluded that it is necessary to use appropriate fructan substrates and to consider the possible involvement of all β-fructofuranosidase activities in hydrolysis of fructans in grasses. [ABSTRACT FROM AUTHOR]

Crude extracts from leaves of Lolium temulentum L. exhibited invertase activity and activity capable of releasing fructose from fructans (fructan exohvdrolase; FEH). The optimum pH for FEH activity was between pH 4.8 and 5.5. When shoots of 10-d-old seedlings were induced to accumulate fructans by cooling their roots to 5 °C and exposing them to continuous light, FEH activity declined by at least 5%. FEH activity increased when the shoots were induced to mobilize the fructans by warming the roots to the ambient temperature (20 °C) and darkening the plants. Declining activity coincided with loss of one of at least two FEH isoforms observed after starch gel electrophoresis. Partially purified FEH from leaves of L. temulentum was inhibited when assayed in the presence of 10 mM sucrose. [ABSTRACT FROM AUTHOR]

The net mobilization of nitrogen compounds (total N, soluble protein, amino N, membrane-bound protein) from different plant parts after defoliation, and the extent to which mobilized nitrogen contributed to new leaf growth, were studied in small swards of Trifolium subterraneum L. cv. Seaton Park (subterranean clover) either completely dependent on nitrogen fixation (-N treatment) or receiving abundant nitrate at defoliation (+N treatment). Net mobilization of nitrogen from nodulated roots (75 % of mobilized nitrogen) and branches (25 % of mobilized nitrogen) accounted for most of the nitrogen in new leaf growth for up to 5 d in - N swards and for at least 2 d in + N swards. In - N swards, nodules degenerating as a result of defoliation were a major source of mobilized nitrogen for 2 d (50 % of mobilized nitrogen), after which the fine roots became the largest net contributor of mobilized nitrogen. Overall, a net 17% of the nitrogen present in residual organs was mobilized. Soluble protein was the major form of mobilized nitrogen for which assays were performed, accounting for 50 % of the decline in total N in the - N treatment. The relative loss of soluble protein from sward components declined in the order, nodules (47 % over 5 d), fine roots (44 % over 9 d), branches (38 % over 9 d) and taproots (37 % over 5 d). The amino N pool increased sharply in size for two days after defoliation, possibly indicating breakdown of soluble protein in excess of the nitrogen demand for regrowth or to provide a respiratory substrate. It was concluded that, in plants of adequate nitrogen status, leaf growth was unlikely to be nitrogen-limited during the first few days after defoliation. [ABSTRACT FROM AUTHOR]

Studies were performed on the binding of tritiated adenosine and its analogues, 5'-N-elhytcarboxiunidc adenosine (NECA) and N6-phenylisopropyladcnosine (PIA), to human peripheral blood lymphocytes. These revealed binding only of adenosine (Kd, 1-10 μM, 14,000) binding sites/cell), which was abolished by dipyridamole, a specific adenosine transport inhibitor, suggesting that the binding is to the nucleoside transporter. The absence of high affinity (Kd ⩽ 1 μM) binding of adenosine or of the two analogues, NECA and PIA suggests that the previously reported effects of adenosine on cAMP formation are not mediated by cell surface specific nucleoside receptors. Binding of adenosine to the carrier in lymphocytes from patients with common variable immunodeficiency was similar to those from control subjects. [ABSTRACT FROM AUTHOR]

The role of 5'-nucleotidase in the uptake of adenosine from AMP was investigated in lymphocytes from normal subjects and patients with common variable hypogamma-globulinaemia (CVH) and chronic lymphatic leukaemia (CLL). At physiological pH, the Km values for the uptake of adenosine and of adenosine from AMP by intact cells were one order of magnitude higher than the Km values for 5-nucleotidase. The Vmax values for the hydrolysis of AMP by 5'-nucleotidase were two orders of magnitude greater than for the uptake of adenosine itself or the uptake of adenosine from AMP by normal lymphocytes. 5'-nucleotidase activity is clearly not rate-limiting in normal lymphocytes for uptake of adenosine from AMP in steady state conditions. Patients with common variable hypogammaglobulinaemia showed a tow Vmax for 5'-nucleotidase assayed at pH 7.4 in intact cells as compared to values from control subjects. Michaelis constants (Km) for the uptake of free adenosine and adenosine from AMP as well as 5'-nucleotidase were similar compared to those obtained for controls. The uptake of adenosine moiety from AMP in CLL lymphocytes with a low Vmax for 5-nucleotidase was also reduced, although not to the same extent as the reduction in 5'-nucleotidase activity. One CLL patient with supranormal levels of 5'-nucleotidase activity showed elevated uptake of adenosine moiety from AMP and of free adenosine. These results suggest that 5'-nucleotidase can influence the salvage of purine by lymphocytes from extracellular nucleotides but only when the enzyme activity is greatly reduced. [ABSTRACT FROM AUTHOR]

Injected recombinant interleukin-6 (IL-6), tumour necrosis factor (TNF) and IL-1 all protect mice against experimental infection with Listeria monocytogenes. We have therefore investigated the interaction of these cytokines during infection. Treatment with recombinant (r)IL-6 enhanced TNF production by spleen cells during the first 2 days of infection. Anti-TNF antibody could totally abolish the protective effect of rIL-6, while the optimal protective function of TNF could not be achieved when IL-6 was neutralized by anti-IL-6 antibody. IL-1 induced a high level of IL-6 in the serum a short time after its administration, and neutralization of IL-6 totally abolished the protective function of rIL-1. The results thus provide further evidence for the complexity of cytokine interaction. [ABSTRACT FROM AUTHOR]

Background and purpose: The interrelation of cognitive performance, cerebrovascular damage and brain functional connectivity (FC) in advanced arteriosclerosis remains unclear. Our aim was to investigate the associations between FC, white matter damage and cognitive impairment in carotid artery disease. Methods: Seventy‐one participants with a recent cerebrovascular event and with written informed consent underwent resting‐state functional magnetic resonance imaging and the Addenbrooke's Cognitive Examination – Revised (ACE‐R). Network and inter‐hemispheric FC metrics were compared between cognitively normal and impaired subjects, and interrelated with cognition. In order to explore the nature of FC changes, their associations with microstructural damage of related white matter tracts and cognitive performance were investigated, followed by mediation analysis. Results: Participants with global cognitive impairment showed reduced FC compared to the cognitively intact subjects within the central executive network (CEN), and between hemispheres. Patients with executive dysfunction had decreased CEN FC whilst patients with memory loss demonstrated low FC in both the CEN and the default mode network (DMN). Global performance correlated with connectivity metrics of the CEN hub with DMN nodes, and between hemispheres. Cingulum mean diffusivity (MD) was negatively correlated with ACE‐R and CEN–DMN FC. The cingulum MD–cognition association was partially mediated by CEN–DMN FC. Conclusions: Long‐range functional disconnection of the CEN with DMN nodes is the main feature of cognitive impairment in elderly subjects with symptomatic carotid artery disease. Our findings provide further support for the connectional diaschisis concept of vascular cognitive disorder, and highlight a mediation role of functional disconnection to explain associations between microstructural white matter tract damage and cognitive impairment. [ABSTRACT FROM AUTHOR]

Cool temperatures can limit productivity of temperate grazing systems as poor pasture growth rates in winter create feed shortages for livestock. Ornithopus spp. (serradella) are broadly adapted annual pasture legumes that produce high-quality forage in soil types considered marginal for other temperate legume species. However, serradella establishment is perceived to be difficult in cool-season environments. We used survival analysis to compare germination rate and seedling emergence for two serradella species (yellow serradella and French serradella) against three reference species (Medicago sativa, M. polymorpha and Trifolium subterraneum) in four temperature treatments (10/5, 15/10, 20/15 and 25/20°C; max/min). We also compared shoot relative growth rate and photosynthetic rate at 15/10°C (cool) and 23/18°C (warm). Cool temperatures (10/5, 15/10°C) did not slow germination rates for serradella relative to the reference species, but warm temperatures (20/15, 25/20°C) delayed emergence and reduced post-emergent shoot growth rates. Once established, Ornithopus spp. had similar mean photosynthetic rates and stomatal conductance at cool temperatures to the reference species.We conclude that, contrary to common perception, cool temperatures did not adversely influence germination, emergence, or early growth of Ornithopus spp. relative to the reference species. [ABSTRACT FROM AUTHOR]

Summary: Cytomegalovirus (CMV) infection is a potentially fatal complication in patients receiving haematopoietic stem cell transplantation (HSCT), but recent evidence indicates that CMV has strong anti‐leukaemia effects due in part to shifts in the composition of natural killer (NK) cell subsets. NK cells are the primary mediators of the anti‐leukaemia effect of allogeneic HSCT, and infusion of allogeneic NK cells has shown promise as a means of inducing remission and preventing relapse of several different haematological malignancies. The effectiveness of these treatments is limited, however, when tumours express human leucocyte antigen (HLA)‐E, a ligand for the inhibitory receptor NKG2A, which is expressed by the vast majority of post‐transplant reconstituted and ex‐vivo expanded NK cells. It is possible to enhance NK cell cytotoxicity against HLA‐Epos malignancies by increasing the proportion of NK cells expressing NKG2C (the activating receptor for HLA‐E) and lacking the corresponding inhibitory receptor NKG2A. The proportion of NKG2Cpos/NKG2Aneg NK cells is typically low in healthy adults, but it can be increased by CMV infection or ex‐vivo expansion of NK cells using HLA‐E‐transfected feeder cells and interleukin (IL)‐15. In this review, we will discuss the role of CMV‐driven NKG2Cpos/NKG2Aneg NK cell expansion on anti‐tumour cytotoxicity and disease progression in the context of haematological malignancies, and explore the possibility of harnessing NKG2Cpos/NKG2Aneg NK cells for cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Background and purpose: The role of clinical factors, cerebral infarcts and hippocampal damage in vascular cognitive impairment (VCI) subtypes remains unclear. Methods: Non-demented patients with carotid stenosis and recent transient ischemic attack/stroke had cognitive assessment and brain magnetic resonance imaging (MRI). Amnestic VCI was defined as memory impairment; nonamnestic VCI was any other subdomain impairment. Associations of MRI metrics [log-transformed total ischemic lesion load (log TILL), mesiotemporal atrophy (MTA) score, hippocampal mean diffusivity (hipMD)] with cognitive performance were assessed. Results: A hundred and eight patients, 47 with amnestic VCI and 21 with non-amnestic VCI, were assessed. A higher MTA (odds ratio 12.89, P = 0.001) and left hipMD (odds ratio 4.43, P = 0.003) contributed to amnestic VCI versus normal. Age-adjusted fluency correlated with log TILL (P = 0.002). Age-adjusted memory was associated with left hipMD (P = 0.001), MTA (P < 0.001) but not log TILL (P = 0.14). Left hipMD, MTA and smoking showed classification potential between amnestic VCI versus normal (area 0.859, P < 0.001). Conclusions: Neuroimaging assists stratification in amnestic VCI characterized by hippocampal changes and in non-amnestic VCI by higher ischemic burden. MTA and hippocampal diffusivity show diagnostic biomarker potential. [ABSTRACT FROM AUTHOR]

Presents a letter regarding the use of computerized tablet to extract data from published dot plot graphs.

Fructan:fructan fructosyltransferase (FFT) activity was purified about 300-fold from leaves of Lolium rigidum Gaudin by a combination of affinity chromatography, gel filtration, anion exchange and isoelectric focusing. The FFT activity was free of sucrose: sucrose fructosyltransferase and invertase activities. It had an apparent pI of 4.7 as determined by isoelectric focusing, and a molecular mass of about 50000 (gel filtration). The FFT activity utilized the trisaccharides 1-kestose and 6G-kestose as sole substrates, but was not able to use 6-kestose as sole substrate. The FFT activity was not saturated when assayed at concentrations of 1-kestose, 6G-kestose or (1,1)- kestotetraose of up to 400 mM The rate of reaction of the FFT activity was most rapid when assayed with 1-kestose and was less rapid when assayed with 6G-kestose, (1,1 )-kestotetraose or (1,1,1 )-kestopentaose. The FFT activity when assayed at a relatively high concentration of enzyme activity (approximately equivalent to about half the activity in crude extracts per gram fresh mass) did not synthesize fructan of degree of polymerization > 6, even during extended assays of up to 10 h. When assayed with a combination of 1-kestose and uniformly labelled [14C]sucrose as substrates, the major reaction was the transfer of a fructosyl residue from 1-kestose to sucrose resulting in the re-synthesis of 1-kestose. Tetrasaccharide and 6G-kestose were also synthesized. When assayed with 6G-kestose and [14C]sucrose as substrates, the major reaction of the FFT activity was the synthesis of tetrasaccharide. However, some synthesis of 1-kestose and re-synthesis of 6G-kestose also occurred. When 6Gkestose was the sole substrate for the FFT activity, synthesis of tetrasaccharide was 2.7 to 3.4-fold slower than when 1-kestose was used as the sole substrate. Owing to differences in the fructan : sucrose fructosyltransferase acitity of the FFT with each of the trisaccharides, net synthesis of tetrasaccharide by the FFT was altered significantly in the presence of sucrose. The magnitude of the effect depended on the concentration of the trisaccharides. In the presence of sucrose, 6Gkestose could be a substrate of equvalent importance to 1-kestose for synthesis of tetrasaccharide. [ABSTRACT FROM AUTHOR]

This paper presents a method for rapid quantification of sucrose and fructans by thin-layer chromatography (TLC) and densitometry. In the optimized protocol, glass-backed TLC plates were developed in a solution of propan-1-ol:ethyl acetate:water (45:35:20, v/v/v) for 3.5 h at 30°C. In this system, sucrose, the fructan trisaccharides: 1-kestose, 6G-kestose and 6-kestose, fructan tetrasaccharide and fructan pentasaccharide were separated. An internal standard of stachyose was useful for most of the applications examined. The fructans were detected by spraying with urea-phosphoric acid and heating at 110 °C for 6 min. The blue colour developed was stable for 18 h provided that plates were kept in the dark. Quantification was achieved by reflectance densitometry and comparison with standards. The standard curves for the oligosaccharides were not linear, owing to the spreading of spots on the TLC plates, but were highly repeatable. The TLC quantification method provided a more rapid analysis of sucrose and fructan oligosaccharides than was possible by high-performance liquid chromatography analysis because time-consuming pre-treatment of samples was not needed. The method will be useful for both enzyme and physiological studies. [ABSTRACT FROM AUTHOR]

A partial separation of sucrose: sucrose fructosyltranferase (SST) activity from invertase activity extracted from leaves of Lolium rigidum Gaudin was achieved by gel filtration. The SST activity was purified 54-fold with a ratio of SST activity to invertase activity of 1:1:1. the partially purified SST activity eluted with an apparent molecular mass of about 68000, had an optimum pH of 5.5 and a Km of 0.12 M. When incubated with sucrose concentrations ranging from 10 to 600 mM the partially purified SST activity produced mainly 1-kestose and some 6-kestose (10-15% of trisaccharide produced). SST and invertase activities declined during storage at -25°C with invertase activity declining at a faster rate. After the loss of invertase activity in storage, the partially purified SST activity synthesized only 1-ketose. When incubated with 1-ketose the partially purified SST activity synthesized neokestose (1.9 nkat ml-1), nystose (2.2 nkat ml-1) and an unidentified tetrasaccharide (1.4 nkat ml-1) indicating that the fructosyltranferase preparation also had FFT-like activity. The partially purified invertase had significant sucrose-hydrolyzing activity (25 nkat ml-1) and contained no measurable SST activity when incubated with 10-400 mM sucrose, but produced trisaccharide (1-kestose and 6-kestose, ratio 1.5:1) when incubated with 600 mM sucrose. L. rigidum does not normally accumulate 6-ketose. The optimum pH of the sucrose-hydrolyzing activity was 4.5 and the optimum pH of the fructosyltranferase activity of the invertase preparation was 5.5. The partially purified invertase did not have significant FFT-like activity. The results support the hypothesis that SST activity synthesizes only 1-kestose, which is a key intermediate in the synthesis of fructan in L. rigidum. [ABSTRACT FROM AUTHOR]

Faecally enriched extracts of Dermatophagoides pteronyssinus were shown to contain a trypsin-like enzyme which was allergenic. Chromatofocusing studies revealed the presence of nine major isoforms in D. pteronyssinus, with pI in the range 4 to > 8, but only two (range 4-5) in D. farinae. Trypsin isolated from D. pieronyssinus by benzamidine-Sepharose 6B affinity chromatography and gel-filtration was found to be a 31-kDa protein which was enzymatically similar to both invertebrate and vertebrate trypsins. The N-terminal sequence obtained (IVGGEXALAGEXPYQISL) was identical to that reported for the mile allergen Der p III and showed homology with crayfish trypsin and Der f III from D. farinae. Mite trypsin underwent autolysis and the N-terminal sequences of two fragments were found to be ALAGEXPYQI and NNQVXGI respectively. Both showed homology with crayfish trypsin, and the former sequence was identical to residues 7-18 of the native enzyme and Der p III. All isoforms of mite trypsin were showed to be allergenic by radioallergosorbent assay and further studies indicated that the trypsin degradation products were also allergenic. The enzyme was compared with other mite allergens and the rank order of allergenic potency was shown to be; whole mite extract > Der p I > trypsin. However, all sera from a panel of mite allergic individuals showed IgE reactivity to trypsin, comparable to that seen using whole mite extract and Der p I. These data indicate that mite trypsin is a major allergen corresponding to the previously described allergen, Derp III. [ABSTRACT FROM AUTHOR]

Temperate pasture legumes (e.g . Trifolium and Medicago spp.) often have a higher phosphorus (P) requirement for maximum productivity than pasture grasses. This is partly attributed to differences between legumes and grasses in their ability to acquire P from soil. We are the first to report differences in root morphology traits important for soil P acquisition in a range of novel pasture legumes being developed for use in temperate pastures of southern Australia. Up to a 3·6-fold range in specific root length (SRL) (79-281 m root g−1 root) and 6·1-fold range in root hair length (RHL) (0·12-0·75 mm) was found between the pasture species. The commonly used Trifolium subterraneum and Medicago sativa had relatively low SRLs and short root hairs, while Ornithopus compressus, O. sativus and Biserrula pelecinus had RHLs and SRLs more similar to those of two grass species that were also assessed. Specific root length was highly correlated with average root diameter, and root traits were relatively stable at different plant ages. We surmise that large differences among pasture legume species in the effective volume of soil explored could translate into significant differences in their critical P requirements (i.e. soil P concentration to achieve 90% of maximum shoot yield). [ABSTRACT FROM AUTHOR]

Cytomegalovirus (CMV) infection markedly expands NKG2C+/NKG2A− NK cells, which are potent killers of infected cells expressing human leucocyte antigen (HLA)-E. As HLA-E is also over-expressed in several haematological malignancies and CMV has been linked to a reduced risk of leukaemic relapse, we determined the impact of latent CMV infection on NK cell cytotoxicity against four tumour target cell lines with varying levels of HLA-E expression. NK cell cytotoxicity against K562 (leukaemia origin) and U266 (multiple myeloma origin) target cells was strikingly greater in healthy CMV-seropositive donors than seronegative donors and was associated strongly with target cell HLA-E and NK cell NKG2C expression. NK cell cytotoxicity against HLA-E transfected lymphoma target cells (221.AEH) was ∼threefold higher with CMV, while NK cell cytotoxicity against non-transfected 721.221 cells was identical between the CMV groups. NK cell degranulation (CD107a+) and interferon (IFN)-γ production to 221.AEH cells was localized almost exclusively to the NKG2C subset, and antibody blocking of NKG2C completely eliminated the effect of CMV on NK cell cytotoxicity against 221.AEH cells. Moreover, 221.AEH feeder cells and interleukin (IL)−15 were found to expand NKG2C+/NKG2A- NK cells preferentially from CMV-seronegative donors and increase NK cell cytotoxicity against HLA-E+ tumour cell lines. We conclude that latent CMV infection enhances NK cell cytotoxicity through accumulation of NKG2C+ NK cells, which may be beneficial in preventing the initiation and progression of haematological malignancies characterized by high HLA-E expression. [ABSTRACT FROM AUTHOR]

Obesity has been associated with accelerated biological ageing and immunosenescence. As the prevalence of childhood obesity is increasing, we wanted to determine if associations between obesity and immunosenescence would manifest in children. We studied 123 Mexican American adolescents aged 10-14 (mean 12·3 ± 0·7) years, with body weights ranging from 30·1 to 115·2 kg (mean 52·5 ± 14·5 kg). Blood samples were obtained to determine proportions of naive, central memory ( CM), effector memory ( EM), senescent and early, intermediate and highly differentiated subsets of CD4+ and CD8+ T cells. Overweight and obese children had significantly lowered proportions of early CD8+ T cells (B = −11·55 and -5·51%, respectively) compared to healthy weight. Overweight children also had more EM (B = +7·53%), late (B = +8·90%) and senescent (B = +4·86%) CD8+ T cells than healthy weight children, while obese children had more intermediate CD8+ (B = +4·59%), EM CD8+ (B = +5·49%), late CD4+ (B = +2·01%) and senescent CD4+ (B = +0·98%) T cells compared to healthy weight children. These findings withstood adjustment for potentially confounding variables, including age, gender and latent cytomegalovirus and Epstein-Barr virus infections. We conclude that excess body mass, even in adolescence, may accelerate immunosenescence and predispose children to increased risks of incurring immune-related health problems in adulthood. [ABSTRACT FROM AUTHOR]

Background The brush border ferric reductase (Dcytb) is critical for the absorption of dietary iron and appears to be expressed on the duodenal enterocyte brush border. The Dcytb expression is increased in severe iron-deficient anaemia, but the situation in a more typical mild iron deficiency is unclear. This study investigated Dcytb expression in patients with normal iron status or mild iron deficiency and its relationships with enterocyte iron status. Materials and methods Duodenal biopsy specimens and blood samples were obtained from 32 patients undergoing routine upper gastrointestinal endoscopy. Twenty-three specimens (six iron-deficient and 17 iron-replete) were processed for light-microscopy (LM) and for immunohistochemistry with antibodies against Dcytb and heavy/light chain ferritin subunits. The nine remaining biopsies (three iron-deficient and six iron-replete) were processed for electron microscopy (EM). Immunolocalization of Dcytb and intracellular ferritin was performed with appropriate primary antibodies followed by 10-nm gold conjugate labels. Results The LM process showed a strong negative correlation between immunolabelling intensity of Dcytb on the enterocyte brush border and serum iron saturation ( P < 0·001), but only a weak negative correlation between this antigen and haemoglobin ( P = 0·08) or serum ferritin concentrations ( P = 0·4). EM confirmed anti-Dcytb preferential labelling of microvilli rather than enterocyte cytoplasm ( P = 0·001), but preferential antiferritin labelling of cytoplasm ( P < 0·02). There was no correlation with enterocyte cytoplasmic ferritin labelling (i.e. enterocyte iron status and Dcytb expression). Conclusions Enterocyte Dcytb brush border expression is increased even in mild iron deficiency and may be related to serum iron saturation. The lack of correlation with enterocyte ferritin expression deserves further study with direct measurement of intracellular iron. [ABSTRACT FROM AUTHOR]

To investigate the functional significance of mutations in Ferroportin that cause hereditary iron overload, we directly measured the iron efflux activity of the proteins expressed in Xenopus oocytes. We found that wild type and mutant Ferroportin molecules (A77D, N144H, Q248H and V162Delta) were all expressed at the plasma membrane at similar levels. All mutations caused significant reductions in (59)Fe efflux compared to wild type but all retained some residual transport activity. A77D had the strongest effect on (59)Fe efflux (remaining activity 9% of wild-type control), whereas the N144H mutation retained the highest efflux activity (42% of control). The Q248H and V162Delta mutations were intermediate between these values. Co-injection of mutant and wild-type mRNAs revealed that the A77D and N144H mutations had a dominant negative effect on the function of the WT protein. [ABSTRACT FROM AUTHOR]

TransgenicTrifolium subterraneumexpressing a phytase gene (phyA) fromAspergillus nigerwere generated. Five independently transformed lines showed an average 77-fold increase in exuded phytase activity in comparison with null segregant and wild-type controls. Unlike other phosphatases, exuded phytase activity was unaffected by P supply, verifying the constitutive expression ofphyA. TransgenicT. subterraneumgrown in agar with P supplied as phytate, took up 1.3- to 3.6-fold more P than controls and had equivalent P uptake to plants supplied with orthophosphate. This unique phenotype was compromised when the plants were grown in soil. None of the five lines showed increased shoot biomass or total P uptake in an unfertilized, low-P soil taken from under permanent pasture. With addition of P, one of the five transgenic lines had consistently greater P nutrition compared with control plants. Despite variable growth and P nutrition responses, P uptake per root length was on average greater for transgenic lines. Exudation of phytase by transgenicT. subterraneumallowed utilization of P from phytate in non-sorbing, sterile laboratory media, but was less effective when plants were grown in soil. Release of extracellular phytase is therefore not the only requirement for the acquisition of P from endogenous soil phytate by plants. [ABSTRACT FROM AUTHOR]

Haem biosynthesis may regulate intestinal iron absorption through changes in cellular levels ofδ-aminolaevulinic acid (ALA), haem and perhaps other intermediates. CoCl2 and NiCl2 are activators of haem oxygenase, the rate-limiting enzyme in haem catabolism. Co2+ and Ni2+ may also regulate and increase iron absorption through a mechanism that simulates hypoxic conditions in the tissues.We assayed intestinal iron absorption in mice dosed with CoCl2 or NiCl2. The effects of these metal ions on splenic and hepatic levels of ALA synthase and dehydratase as well as urinary levels of ALA and phosphobilinogen were also assayed.While Co2+ enhanced iron absorption when administered to mice at doses of 65, 125 and 250 µmoles kg−1 body weight, Ni2+ was effective only at the highest dose. Ni2+ but not Co2+ at the highest dose reduced urinary ALA in the treated mice. Both metals ions increased splenic expression of haem oxygenase 1 and iron regulated protein 1, proteins involved, respectively, in haem degradation and iron efflux. Co2+ induced erythropoietin expression.The data suggest that while the effect of Ni2+ on iron absorption could be explained by effects on ALA, the effect of Co2+ may not be explained simply by changes in haem metabolism; therefore, effects mediated by alterations of specific haemoproteins by mechanisms that simulate tissue hypoxia could be important.Eur J Clin Invest 2004; 34 (9): 626 – 630 [ABSTRACT FROM AUTHOR]

ABSTRACTDcytb has been identified as the mammalian transplasma ferric reductase that catalyzes the reduction of ferric to ferrous iron in the process of iron absorption. Its mRNA and protein levels are up-regulated by several independent stimulators of iron absorption. Furthermore, its cDNA encodes putative binding sites for heme and ascorbic acid. Using Northern and Western blots, RT-PCR and confocal microscopy, we studied the expression and localisation of Dcytb in cell lines and tissues of CD1 mice. Dcytb expression and function were modulated by iron. Dcytb and DMT1, both predominantly localised in the apical region of the duodenum were up-regulated in iron deficiency. Dcytb, the iron regulated ferric reductase may also utilize cytoplasmic ascorbate as electron donor for transmembrane reduction of iron. Dcytb expression was found in other tissues apart from the duodenum and its regulation and functions at these other sites are of interest in iron metabolism. [Copyright &y& Elsevier]

Abstract Background HFE knockout mice (C57BL/6 × 129/Ola strain) mimic the functional aberrations of human hereditary haemochromatosis (HH) in short-term experiments. The present study investigates functional and morphological long-term changes. Methods HFEo/o , HFE+/o and HFE+/+ mice were maintained on iron-rich and control diets for 2 weeks, 3, 12 and 18 months. Light microscopic tissue iron distribution, pathomorphological alterations, tissue iron content and oxidative stress were analysed in liver, pancreas, spleen, gastrointestinal tract, kidneys and myocardium. Additionally, duodenal 59 Fe absorption and 59 Fe whole body loss were measured. Results Iron distribution between organs and microscopic iron deposition in the tissues resembled the patterns described in HH. After 3 months of iron-rich feeding duodenal 59 Fe absorption decreased to ∼15% of iron-adequate controls but remained about twice as high in HFEo/o as in HFE+/+ mice. Hepatic iron concentrations reached only half the values known to induce hepatic fibrosis in rats and humans, while whole body 59 Fe loss was about twice as high. Consequently no hepatic fibrosis developed, although massive hepatocellular iron deposition and indication for oxidative stress were observed. Conclusion C57BL/6 × 129/O1a HFEo/o mice mimic HH iron distribution and the regulation of intestinal iron absorption after long-term feeding. However, characteristic morphological late changes in untreated HH are not modelled. [ABSTRACT FROM AUTHOR]

Background: A part of the mechanism of the gastrointestinal toxicity exhibited by non-steroidal anti-inflammatory drugs is believed to involve the uncoupling of mitochondrial oxidative phosphorylation. Most previous uncoupling studies have used rat liver mitochondria. There is little information on the effects of the drugs on mitochondria from other species. Aim: To study the effect of indometacin on isolated liver mitochondria from rats, mice and humans. Methods: We studied the effects of indometacin on respiration and adenosine triphosphate synthesis by isolated liver mitochondria from rats, mice and humans. Its effects were compared with those of dinitrophenol, a classical uncoupler. Results: Indometacin uncoupled oxidative phosphorylation at low concentrations (P < 0.05) and inhibited respiration at high concentrations (P < 0.01) in all three species. Adenosine triphosphate synthesis was, however, more sensitive to dinitrophenol or indometacin at lower concentrations in mouse and human compared to rat liver mitochondria (P < 0.05). Conclusions: The current study shows that indometacin acts as an inhibitory uncoupler in human mitochondria. It also demonstrates that the responses of rat, mouse and human mitochondria to indometacin are broadly similar. [ABSTRACT FROM AUTHOR]

Aggressive lipid management is likely beneficial for coronary artery disease patients with diabetes mellitus or of advanced age. Nevertheless, a study of a large national sample of patients seen in ambulatory medical practices suggests pharmacologic undertreatment in these high-risk groups. [ABSTRACT FROM AUTHOR]

Increased left ventricular (LV) mass is often found in adults and is a powerful predictor of cardiovascular mortality. To test the hypothesis that an electrocardiographic estimate of LV mass--the Cornell voltage--is associated with ventricular premature complexes (VPCs) in free-living adults, a cross-sectional analysis of the predictors of VPCs on a 2-minute rhythm strip in a population-based sample of 13,606 middle-aged, African-American and white men and women from 4 US communities in the Atherosclerosis Risk in Communities Study baseline examinations was performed. In adults without known coronary artery disease, the prevalence of VPCs increases monotonically with increasd Cornell voltages within ethnicity and gender groups. Independent of systemic hypertension, serum electrolytes, age, heart rate, educational attainment, gender, and ethnicity, a millivolt increase in Cornell voltage was associated with a 20% to 30% increase in the prevalence odds ratio of VPCs on the 2-minute electrocardiogram. Thus, Cornell voltage is associated with VPCs on a 2-minute electrocardiogram. The association is consistent in African-Americans, whites, men, and women. [ABSTRACT FROM AUTHOR]

Patients discharged from the hospital on an angiotensin-converting enzyme inhibitor had a significant decrease in 30-day death or readmission (by 30% in 1,195 unselected Medicare patients hospitalized with congestive heart failure). Other independent predictors of poor outcome determined by multivariate analysis included history of congestive heart failure, male gender, increased number of comorbidities, higher serum blood urea nitrogen, and lower serum sodium. [ABSTRACT FROM AUTHOR]

Panic disorder with or without agoraphobia is a prevalent clinical disorder which places heavy demands on treatment resources in primary care. The efficiency of delivery of psychological treatments for this disorder is therefore important. Previous research has focused on psychological treatments delivered with reduced therapist contact but methodological problems preclude firm conclusions. The present study investigated the relevance of therapist contact in cognitive behaviour therapy for panic disorder and agoraphobia, taking account of previous methodological problems. One hundred and four patients suffering from DSM III-R panic disorder with or without agoraphobia were randomly allocated to receive cognitive behaviour therapy with either, ‘standard’ therapist contact, ‘minimum’ therapist contact or as a bibliotherapy. All patients were seen by the same therapist and all received an identical treatment manual. Treatment response, as measured by patient and therapist report scales of anxiety, depression, and agoraphobic avoidance, was analysed in terms of both traditional statistical significance and clinical significance of outcome. At treatment end-point the ‘standard’ therapist contact and ‘minimum’ therapist contact groups showed significant reductions pre- to post-treatment on all measures. Pre- to post-treatment reductions for the bibliotherapy group were significant on therapist- and patient-rated measures of anxiety only. The ‘standard’ therapist contact group was consistently significantly improved in comparison to the bibliotherapy group. Significant differences between the ‘standard’ and ‘minimum’ therapist contact groups were found on therapist-rated anxiety only. Assessment of clinical significance of treatment outcome showed further differences between treatment groups with the ‘standard’ therapist contact group showing the largest proportion of patients achieving clinically significant change on all measures both at treatment end-point and at 6-month follow-up. Copyright © 2000 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

There is a lack of data evaluating the implementation of guidelines in the management of coronary artery disease (CAD) or congestive heart failure (CHF) in the outpatient setting. We analyzed an administrative data set from the Merck & Co. sponsored national Quality Assurance Program, a retrospective outpatient chart audit of 58,890 adult outpatients from 140 medical practices (80% cardiology only) in the USA with diagnoses of CAD and/or CHF identified from medical claims data. We determined the (1) frequency of lipid documentation and prescription of lipid-lowering agents in patients with CAD, (2) frequency of assessment of left ventricular function and prescription of an angiotensin-converting enzyme inhibitor in patients with CHF, and (3) predictors of medication prescription. Of the 48,586 patients with CAD, 44% had annual diagnostic testing of low-density lipoprotein cholesterol. Only 25% of these patients reached the target low-density lipoprotein cholesterol of < or = 100 mg/dl, and only 39% were taking lipid-lowering therapy, which was less among the elderly than in the younger patients. Of the 16,603 patients with CHF, 64% had diagnostic testing of left ventricular function, and 50% of patients were taking an angiotensin-converting enzyme inhibitor; 67% of patients received medication if they had documented systolic dysfunction. Significant predictors of medication prescription included diagnostic testing, younger age, history of myocardial infarction or coronary artery bypass grafting, hypertension, cardiology specialty, and geographic region. Thus, current practice patterns in the management of CAD and CHF are inadequate. Patient age, diagnostic testing, and practice environment influence medication prescription. [ABSTRACT FROM AUTHOR]

The products formed by a fructan : fructan fructosyltransferase (FFT) activity purified from Lolium rigidum Gaudin were identified after gas chromatography-mass spectrometry of partially methylated alditol acetates, electrospray ionization-mass spectrometry and reversed-phase high-performance liquid chromatography. The FFT activity synthesized oligofructans up to degree of polymerization (DP) 6, but did not synthesize fructans of DP> 6 even when assayed with (1,1,1)-kestopentaose for up to 10 h. The FFT activity when assayed with 1- kestose or 6G-kestose synthesized fructan with fructosyl residues almost exclusively linked by β-2,1-glycosidic linkages. When assayed with 1-kestose, the FFT activity synthesized tetrasaceharides and pentasaccharides with an internal glucosyl residue. The predominant tetrasaccharide was (1&6G)-kestotetraose and the predominant pentasaccharide was (1&6G,1)-kestopentaose. By comparison, tetrasaccharides and pentasaccharides extracted from L. rigidum also contained predominantly β-2,1-glycosidic linked fructans with an internal glucosyl residue. The only exception was that one of the pentasaccharides contained β-2,1- and β-2,6-glycosidic linked fructosyl residues. This pentasaccharide was not synthesized by the FFT activity. The role of this FFT activity in formation of oligofructans in L. rigidum is discussed. [ABSTRACT FROM AUTHOR]

Fructan pentasaccharides were purified, in quantities suitable for use as substrates for enzyme assays, from Neosugar-P (Meiji Seika Kaisha Ltd., Japan), tubers of Helianthus tuberosus L., and stems and leaf sheaths of Triticum aestivum L. by a combination of gel-filtration and RP-HPLC. Fructan of higher molecular mass (mean DP - 30) was purified from leaves of Lolium rigidum Gaud. that had been induced to accumulate fructan and characterized along with the commercially available fructan from Cichorium intybus L. (Sigma, St Louis, USA) (mean DP = 33). The fructan pentasaccharide purified from H. tuberosus was found to contain exclusively 2,1- linked fructose and terminal fructose and terminal glucose, and was identified as (1,1,1)-kestopentaose. The fructan pentasaccharide purified from Neosugar-P also contained (1,1,1)-kestopentaose, although the presence of 3% 1,6-linked glucose and 1% 2,6-linked fructose indicated that a small proportion of other kestopentaoses were present. The fructan pentasaccharide purified from T. aestivum consisted of almost exclusively 2,6-linked fructose and terminal glucose and terminal fructose and was considered to contain predominantly (6,6,6)-kestopentaose. The presence of 1% 2,1,6-linked fructose indicated the sample also contained a small proportion of branched kestopentaose. The high molecular mass fructan from C. intybus was found to comprise linear molecules containing only 2,1-linked fructose, terminal glucose and terminal fructose. High molecular mass fructan from L. rigidum contained predominantly 2,6-linked fructose, had predominantly internal glucose, indicated by 2% 1,6-linked glucose, low levels of branching, indicated by 2% 2,1,6-linked fructose residues and 1% of the residues were 2,1-linked fructose. [ABSTRACT FROM AUTHOR]

Provides information on a study that used intravenous amiodarone for the treatment of patients during prolonged in-hospital resuscitation from refractory cardiac arrest. Diseases of the patients; Result of intial rescucitative efforts; Effect of intravenous amiodarone.

Yellowballs are a collection of approximately 900 compact, infrared sources identified and named by volunteers participating in the Milky Way Project (MWP), a citizen science project that uses GLIMPSE/MIPSGAL images from Spitzer to explore topics related to Galactic star formation. In this paper, through a combination of catalog cross-matching and infrared color analysis, we show that yellowballs are a mix of compact star-forming regions, including ultra-compact and compact H II regions, as well as analogous regions for less massive B-type stars. The resulting MWP yellowball catalog provides a useful complement to the Red MSX Source survey. It similarly highlights regions of massive star formation, but the selection of objects purely on the basis of their infrared morphology and color in Spitzer images identifies a signature of compact star-forming regions shared across a broad range of luminosities and, by inference, masses. We discuss the origin of their striking mid-infrared appearance and suggest that future studies of the yellowball sample will improve our understanding of how massive and intermediate-mass star-forming regions transition from compact to more extended bubble-like structures. [ABSTRACT FROM AUTHOR]