Biology and host range of Tecmessa elegans (Lepidoptera: Notodontidae), a leaf-feeding moth evaluated as a potential biological control agent for Schinus terebinthifolius (Sapindales: Anacardiaceae) in the United States

During surveys for natural enemies that could be used as classical biological control agents of Schinus terebinthifolius Raddi (Brazilian pepper), the caterpillar, Tecmessa elegans Schaus (Lepidoptera: Notodontidae), was recorded feeding on the leaves of the shrub in South America. The biology and larval and adult host range of this species were examined to determine the insect's suitability for biological control of this invasive weed in North America and Hawaii. Biological observations indicate that the larvae have five instars. When disturbed, the late instar larvae emit formic acid from a prothoracic gland that may protect larvae from generalist predators. Larval host range tests conducted both in South and North America indicated that this species feeds and completes development primarily on members of the Anacardiaceae within the tribe Rhoeae. Oviposition tests indicated that when given a choice in large cages the adults will select the target weed over Pistacia spp. However, considering the many valued plant species in its host range, especially several North American natives, this species will not be considered further for biological control of S. terebinthifolius in North America.     

Acute phase protein response in the capybara (Hydrochoerus hydrochaeris)

We evaluated the acute phase protein response in capybaras (Hydrochoerus hydrochaeris). Three animal groups were used: 1) healthy animals (n=30), 2) a group in which experimental inflammation with turpentine was induced (n=6), and 3) a group affected with sarcoptic scabies (n=14) in which 10 animals were treated with ivermectin. Haptoglobin (Hp), acid-soluble glycoprotein (ASG) and albumin were analyzed in all animals. In those treated with turpentine, Hp reached its maximum value at 2 wk with a 2.7-fold increase, whereas ASG increased 1.75-fold and albumin decreased 0.87-fold 1 wk after the induction of inflammation. Capybaras affected with sarcoptic scabies presented increases in Hp and ASG of 4.98- and 3.18-fold, respectively, and a 0.87-fold decrease in albumin, compared with healthy animals. Haptoglobin and ASG can be considered as moderate, positive acute phase proteins in capybaras because they showed less than 10-fold increases after an inflammatory process and reached their peak concentrations 1 wk after the induction of inflammation. Conversely, albumin can be considered a negative acute phase protein in capybaras because it showed a reduction in concentration after inflammatory stimulus.     

Cytochrome c6-like protein as a putative donor of electrons to photosystem I in the cyanobacterium Nostoc sp. PCC 7119

Most organisms performing oxygenic photosynthesis contain either cytochrome c ₆ or plastocyanin, or both, to transfer electrons from cytochrome b ₆-f to photosystem I. Even though plastocyanin has superseded cytochrome c ₆ along evolution, plants contain a modified cytochrome c ₆, the so called cytochrome c _6A, whose function still remains unknown. In this article, we describe a second cytochrome c ₆ (the so called cytochrome c ₆-like protein), which is found in some cyanobacteria but is phylogenetically more related to plant cytochrome c _6A than to cyanobacterial cytochrome c ₆. In this article, we conclude that the cytochrome c ₆-like protein is a putative electron donor to photosystem I, but does play a role different to that of cytochrome c ₆ and plastocyanin as it cannot accept electrons from cytochrome f. The existence of this third electron donor to PSI could explain why some cyanobacteria are able to grow photoautotrophically in the absence of both cytochrome c ₆ and plastocyanin. In any way, the Cyt c ₆-like protein from Nostoc sp. PCC 7119 would be potentially utilized for the biohydrogen production, using cell-free photosystem I catalytic nanoparticles.     

Membrane insertion stabilizes the structure of TrwB, the R388 conjugative plasmid coupling protein

TrwB is an integral membrane protein that plays a crucial role in the conjugative process of plasmid R388. We have recently shown [Vecino et al., Biochim. Biophys. Acta 1798(11), 2160-2169 (2010)] that TrwB can be reconstituted into liposomes, and that bilayer incorporation increases its affinity for nucleotides and its specificity for ATP. In the present contribution we examine the structural effects of membrane insertion on TrwB, by comparing the protein in reconstituted form and in the form of protein/lipid/detergent mixed micelles. TrwB was reconstituted in PE:PG:CL (76.3:19.6:4.1mol ratio) with a final 99:1 lipid:protein mol ratio. This lipid mixture is intended to mimic the bacterial inner membrane composition, and allows a more efficient reconstitution than other lipid mixtures tested. The studies have been carried out mainly using infrared spectroscopy, because this technique provides simultaneously information on both the lipid and protein membrane components. Membrane reconstitution of TrwB is accompanied by a decrease in β-sheet contents and an increase in β-strand structures, probably related to protein-protein contacts in the bilayer. The predominant α-helical component remains unchanged. The bilayer-embedded protein becomes thermally more stable, and also more resistant to trypsin digestion. The properties of the bilayer lipids are also modified in the presence of TrwB, the phospholipid acyl chains are slightly ordered, and the phosphate groups at the interface become more accessible to water. In addition, we observe that the protein thermal denaturation affects the lipid thermal transition profile.     

Beyond sepsis pathophysiology with cytokines: what is their value as biomarkers for disease severity?

Sepsis is a major challenge in medicine. It is a common and frequently fatal infectious condition. The incidence continues to increase, with unacceptably high mortality rates, despite the use of specific antibiotics, aggressive operative intervention, nutritional support, and anti-inflammatory therapies. Typically, septic patients exhibit a high degree of heterogeneity due to variables such as age, weight, gender, the presence of secondary disease, the state of the immune system, and the severity of the infection. We are at urgent need for biomarkers and reliable measurements that can be applied to risk stratification of septic patients and that would easily identify those patients at the highest risk of a poor outcome. Such markers would be of fundamental importance to decision making for early intervention therapy or for the design of septic clinical trials. In the present work, we will review current biomarkers for sepsis severity and especially the use of cytokines as biomarkers with important pathophysiological role.     

fecB, a gene potentially involved in iron transport in Mycobacterium avium, is not induced within macrophages

FecB is a protein involved in the transport of iron from ferric citrate in Escherichia coli and is present in the Mycobacterium tuberculosis genome sequence. Since the ability to retrieve iron from the host is crucial and may be related to virulence, we characterized the gene fecB from Mycobacterium avium, strain 101. An E. coli-mycobacterial shuttle plasmid with a fecB-promoter green fluorescence protein (gfp)-fusion was transformed into M. avium strain 104 to study the fecB-regulation. In vitro, the fecB expression in M. avium weakly correlated with the amount of iron present in the medium but the expression was maximal when there was no iron in the culture medium. In macrophages, M. avium fec B was not induced during the early phase of infection, suggesting that the iron concentration in the mycobacterial phagosome is not sufficiently low to stimulate the expression of fecB in M. avium.     

A Conserved Arginine-Rich Motif within the Hypervariable N-Domain of Drosophila Centromeric Histone H3 (CenH3CID) Mediates BubR1 Recruitment

Background

Centromere identity is determined epigenetically by deposition of CenH3, a centromere-specific histone H3 variant that dictates kinetochore assembly. The molecular basis of the contribution of CenH3 to centromere/kinetochore functions is, however, incompletely understood, as its interactions with the rest of centromere/kinetochore components remain largely uncharacterised at the molecular/structural level.

Principal Findings

Here, we report on the contribution of Drosophila CenH3^CID to recruitment of BubR1, a conserved kinetochore protein that is a core component of the spindle attachment checkpoint (SAC). This interaction is mediated by the N-terminal domain of CenH3^CID (NCenH3^CID), as tethering NCenH3^CID to an ectopic reporter construct results in BubR1 recruitment and BubR1-dependent silencing of the reporter gene. Here, we also show that this interaction depends on a short arginine (R)-rich motif and that, most remarkably, it appears to be evolutionarily conserved, as tethering constructs carrying the highly divergent NCenH3 of budding yeast and human also induce silencing of the reporter. Interestingly, though NCenH3 shows an exceedingly low degree of conservation, the presence of R-rich motives is a common feature of NCenH3 from distant species. Finally, our results also indicate that two other conserved sequence motives within NCenH3^CID might also be involved in interactions with kinetochore components.

Conclusions

These results unveil an unexpected contribution of the hypervariable N-domain of CenH3 to recruitment of kinetochore components, identifying simple R-rich motives within it as evolutionary conserved structural determinants involved in BubR1 recruitment.     

On the reliability of a simple method for scoring phenotypes to estimate heritability: A case study with pupal color in Heliconius erato phyllis, Fabricius 1775 (Lepidoptera, Nymphalidae)

In this paper, two methods for assessing the degree of melanization of pupal exuviae from the butterfly Heliconius erato phyllis, Fabricius 1775 (Lepidoptera, Nymphalidae, Heliconiini) are compared. In the first method, which was qualitative, the exuviae were classified by scoring the degree of melanization, whereas in the second method, which was quantitative, the exuviae were classified by optical density followed by analysis with appropriate software. The heritability (h(2)) of the degree of melanization was estimated by regression and analysis of variance. The estimates of h (2) were similar with both methods, indicating that the qualitative method could be particularly suitable for field work. The low estimates obtained for heritability may have resulted from the small sample size (n = 7-18 broods, including the parents) or from the allocation-priority hypothesis in which pupal color would be a lower priority trait compared to morphological traits and adequate larval development.     

Circadian rhythm of physiological color change in the amphibian Bufo ictericus under different photoperiods

Ectothermic vertebrates can exhibit chromatic adaptation to the environment. The aim of this work was to characterize the rhythm of color change of the amphibian Bufo ictericus, submitted to different photoperiodic regimens, as quantified by skin reflectance values. Adult males were maintained under a 12:12 Light/Dark (LD) cycle during seven days before every experiment. During the experiments, animals were kept in individual boxes for 8 days, under the following photoperiodic regimens: LD 12:12, LD 14:10, DD and LL. In the last 3 days of the treatments, the reflectance of the toad dorsal skins was measured at 3-h intervals, with the aid of a reflectometer. A 3-day time series consisting of 8 data points per day was obtained, which was analyzed by the Cosinor method. The analysis demonstrated that the reflectance values exhibited significant circadian oscillations in the regimens LD 12:12, LD 14:10 and DD, suggesting that the specie B. ictericus shows an effective circadian rhythm of color change. The reflectance values did not exhibit a significant circadian rhythm in the LL regimen showing that this is a condition not permissive for the expression of the color change rhythm.