Structure and dynamics of southern Chilean natural forests with special reference to the relation of evergreen versus deciduous elements

This contribution aims to improve our knowledge of the structural peculiarities of natural forest communities in southern Chile, paying special attention to leaf lifespan and morphology. Species are classified into 17 life-form categories. Using information contained in Braun-Blanquet relevés, the relative frequency of the life-form categories, based on quantitative importance such as cover degree (not mere species numbers), is calculated for 26 natural forests. Communities are categorized as belonging to six different types: (A) evergreen forests; (B) forests with mixed laurophyll-deciduous canopy; (C) forests with mixed canopy of sclerophyllous or small / needle-leaved evergreens and deciduous species (specifically C.1 with dwarf-shrub or grass field layer, and C.2 with laurophyll and mesophyll shrubs and a relatively sparse field layer); and (D) deciduous forests (specifically D.1 with laurophyll undergrowth, and D.2 with a herbaceous ground cover). In the gradient from warm and dry to cool and wet, the characteristic composition of the structural elements reflects climatic site properties, revealed by the distribution of the vegetation units. This gradient represents a gradual retreat of evergreen elements from top (upper tree layer) to bottom (undergrowth), which always follows the order from laurophyllous to sclerophyllous elements, and from small or needle-leaved to deciduous elements. Finally, this retreat terminates in the rare structural type characterized by purely herbaceous ground cover beneath a deciduous canopy. Shifts between structural types do not necessarily involve variation in species composition. These units, reacting rapidly even to slight changes in site conditions, seem to be especially well-suited to monitor changing climatic effects. Human impact on forests, resulting in community shifts towards vegetation of warmer and drier habitats, causes structural changes, as does natural disturbance.     

Lysosomal storage of sulfated glycosaminoglycans in renal interstitial cells of rats treated with tilorone

Summary This investigation provides histochemical evidence for lysosomal storage of sulfated glycosaminoglycans (GAGs) in the interstitial cells of the renal cortex and in macrophage-like cells of the renal medullary zones of rats chronically treated with the drug tilorone. This compound is known to interfere with lysosomal degradation of sulfated GAGs; therefore cells that develop GAG-storage can be assumed to be involved in the turnover of GAGs. In view of this consideration, the most remarkable and still unexplained finding was that the intrinsic interstitial cells in the papilla, which is known to be particularly rich in sulfated GAGs, did not show the cytological symptoms of lysosomal GAG-storage. The present findings may stimulate further studies focused on the cellular sites of turnover of the sulfated GAGs present in the renal medullary interstitium.     

Interspecies interactions within oral microbial communities.

While reductionism has greatly advanced microbiology in the past 400 years, assembly of smaller pieces just could not explain the whole! Modern microbiologists are learning "system thinking" and "holism." Such an approach is changing our understanding of microbial physiology and our ability to diagnose/treat microbial infections. This review uses oral microbial communities as a focal point to describe this new trend. With the common name "dental plaque," oral microbial communities are some of the most complex microbial floras in the human body, consisting of more than 700 different bacterial species. For a very long time, oral microbiologists endeavored to use reductionism to identify the key genes or key pathogens responsible for oral microbial pathogenesis. The limitations of reductionism forced scientists to begin adopting new strategies using emerging concepts such as interspecies interaction, microbial community, biofilms, polymicrobial disease, etc. These new research directions indicate that the whole is much more than the simple sum of its parts, since the interactions between different parts resulted in many new physiological functions which cannot be observed with individual components. This review describes some of these interesting interspecies-interaction scenarios.     

Beta-D-Allose inhibits fruiting body formation and sporulation in Myxococcus xanthus

Myxococcus xanthus, a gram-negative soil bacterium, responds to amino acid starvation by entering a process of multicellular development which culminates in the assembly of spore-filled fruiting bodies. Previous studies utilizing developmental inhibitors (such as methionine, lysine, or threonine) have revealed important clues about the mechanisms involved in fruiting body formation. We used Biolog phenotype microarrays to screen 384 chemicals for complete inhibition of fruiting body development in M. xanthus. Here, we report the identification of a novel inhibitor of fruiting body formation and sporulation, beta-d-allose. beta-d-Allose, a rare sugar, is a member of the aldohexose family and a C3 epimer of glucose. Our studies show that beta-d-allose does not affect cell growth, viability, agglutination, or motility. However, beta-galactosidase reporters demonstrate that genes activated between 4 and 14 h of development show significantly lower expression levels in the presence of beta-d-allose. Furthermore, inhibition of fruiting body formation occurs only when beta-d-allose is added to submerged cultures before 12 h of development. In competition studies, high concentrations of galactose and xylose antagonize the nonfruiting response to beta-d-allose, while glucose is capable of partial antagonism. Finally, a magellan-4 transposon mutagenesis screen identified glcK, a putative glucokinase gene, required for beta-d-allose-mediated inhibition of fruiting body formation. Subsequent glucokinase activity assays of the glcK mutant further supported the role of this protein in glucose phosphorylation.     

The cobalamin precursor cobinamide detoxifies nitroprusside-generated cyanide

Sodium nitroprusside is used to treat hypertensive emergencies and acute heart failure. It acts by releasing nitric oxide (NO), a highly potent vasodilator, but unfortunately, for each NO molecule released, five cyanide ions are released. Thus, nitroprusside therapy is limited by cyanide toxicity. Therefore, a cyanide scavenger could be beneficial when administering nitroprusside. Hydroxocobalamin, which has a relatively high binding affinity for cyanide, has been shown to reduce cyanide levels in nitroprusside-treated patients. Cobinamide, the penultimate precursor in hydroxocobalamin biosynthesis, has a much greater affinity for cyanide than cobalamin, and binds two cyanide ions. We now show that cobinamide is highly effective in neutralizing cyanide ions released by nitroprusside in cultured mammalian cells, Drosophila melanogaster, and mice. Cobinamide also binds NO, but at molar concentrations 2.5-5 times that of nitroprusside, it did not decrease NO concentrations or the physiological effectiveness of nitroprusside. We conclude that cobinamide could be a valuable adjunct to nitroprusside therapy.     

Butterfly Density and Behaviour in Uncut Hay Meadow Strips: Behavioural Ecological Consequences of an Agri-Environmental Scheme

Sparing zones from mowing has been proposed, and applied, to improve local conditions for survival and reproduction of insects in hay meadows. However, little is known about the efficiency of refuge zones and the consequences for local populations. We studied population densities of butterflies before and after mowing in the refuge zone of 15 meadows in 2009 and 2011. We also studied the behaviour of the meadow brown (Maniola jurtina) comparing nectar use, interactions and flights in the refuge zone before and after mowing. Densities of grassland butterflies in this zone doubled on average after mowing. The density of females of M. jurtina increased on average fourfold, while males showed a more modest increase. In line with the idea of increased scramble competition in the refuge zone after mowing, M. jurtina increased the time spent on nectar feeding, the preferred nectar source was visited more frequently, and females made more use of non-preferred nectar sources. Maniola jurtina did not interact more with conspecifics after mowing, but interactions lasted longer. Flight tracks did not change in linearity, but were faster and shorter after mowing. After mowing, only a part of the local grassland butterflies moved to the uncut refuge zone. The resulting concentration effect alters the time allocated to different activities, nectar use and movements. These aspects have been largely ignored for agri-environmental schemes and grassland management in nature reserves and raise questions about optimal quantities and quality of uncut refuge sites for efficient conservation of grassland arthropods in agricultural landscapes.     

Medication Underuse in Aging Outpatients with Cardiovascular Disease: Prevalence,Determinants, and Outcomes in a Prospective Cohort Study

Background

Cardiovascular disease is a leading cause of death in older people, and the impact of being exposed or not exposed to preventive cardiovascular medicines is accordingly high. Underutilization of beneficial drugs is common, but prevalence estimates differ across settings, knowledge on predictors is limited, and clinical consequences are rarely investigated.

Methods

Using data from a prospective population-based cohort study, we assessed the prevalence, determinants, and outcomes of medication underuse based on cardiovascular criteria from Screening Tool To Alert to Right Treatment (START).

Results

Medication underuse was present in 69.1% of 1454 included participants (mean age 71.1 ± 6.1 years) and was significantly associated with frailty (odds ratio: 2.11 [95% confidence interval: 1.24–3.63]), body mass index (1.03 [1.01–1.07] per kg/m²), and inversely with the number of prescribed drugs (0.84 [0.79–0.88] per drug). Using this information for adjustment in a follow-up evaluation (mean follow-up time 2.24 years) on cardiovascular and competing outcomes, we found no association of medication underuse with cardiovascular events (fatal and non-fatal) (hazard ratio: 1.00 [0.65–1.56]), but observed a significant association of medication underuse with competing deaths from non-cardiovascular causes (2.52 [1.01–6.30]).

Conclusion

Medication underuse was associated with frailty and adverse non-cardiovascular clinical outcomes. This may suggest that cardiovascular drugs were withheld because of serious co-morbidity or that concurrent illness can preclude benefit from cardiovascular prevention. In the latter case, adapted prescribing criteria should be developed and evaluated in those patients.     

Lower Ipsilateral Hippocampal Integrity after Ischemic Stroke in Young Adults: A Long-Term Follow-Up Study

MethodsWe included all consecutive first-ever ischemic stroke patients, without hippocampal strokes or recurrent stroke/TIA, aged 18–50 years, admitted to our academic hospital between 1980 and 2010. One hundred and forty-six patients underwent T1 MPRAGE, DTI scanning and completed the Rey Auditory Verbal Learning Test and were compared with 84 stroke-free controls. After manual correction of hippocampal automatic segmentation, we calculated mean hippocampal fractional anisotropy (FA) and diffusivity (MD).ResultsOn average 10 years after ischemic stroke, lesion volume was associated with lower ipsilateral hippocampal integrity (p<0.05), independent of hippocampal volume. In patients with a normal ipsilateral hippocampal volume (volume is less than or equal to 1.5 SD below the mean volume of controls) significant differences in ipsilateral hippocampal MD were observed (p<0.0001). However, patients with a normal hippocampal volume and high hippocampal MD did not show a worse memory performance compared with patients with a normal volume and low hippocampal MD (p>0.05).ConclusionsPatients with average ipsilateral hippocampal volume could already have lower ipsilateral hippocampal integrity, although at present with no attendant worse memory performance compared with patients with high hippocampal integrity. Longitudinal studies are needed to investigate whether a low hippocampal integrity after stroke might lead to exacerbated memory decline with increasing age.     

Effect of increased expression of protein disulfide isomerase and heavy chain binding protein on antibody secretion in a recombinant CHO cell line

Previous work has shown that a human-antibody-producing recombinant CHO cell line did not increase its intracellular content of protein disulfide isomerase (PDI) and heavy chain binding protein (BIP) according to the increasing expression of antibody. It was also found that the intracellular assembly of light and heavy chain is a major limiting factor for overall cell specific productivity, as secretion rates improve with higher light chain expression levels and heavy chain accumulates intracellularly when too little light chain is present. As these CHO cells had a significantly lower intracellular PDI content compared to that of hybridoma cells, these results have led us to try to overcome the limitation in the posttranslational assembly in the endoplasmatic reticulum. Recombinant CHO cells were transfected with PDI or BIP alone or in combination, and the effect on intracellular light and heavy chain content and specific production rate was determined. Overexpression of BIP, both alone and in combination with PDI, reduced the specific secretion rate, whereas PDI, when overexpressed alone, caused an increase of product secretion rate.