Properties of melanin from Lachnum YM156 and its hepatoprotective effect in Cd-exposure mice

Natural melanin was extracted from Lachnum YM156 (LIM). LIM had better thermostability and light resistance, and its solubility was relatively high under alkaline conditions. Simultaneously, we examined its hepatoprotective effect in Cd-exposure mice. Cd-exposure resulted in decreasing weight growth rate, raised liver index, elevated serum levels of alanine aminotransferase (ALT) and aspartate aminotransaminase (AST), and increased Cd accumulation in livers. Hepatic oxidative stress was evidenced by increased malondialdehyde (MDA) contents, decreased glutathione (GSH) contents, and decreased activities of dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) after CdCl₂ administration. Additionally, Cd-exposure also increased the liver level of tumor necrosis factor (TNF)-α and interleukin(IL)-1β. Furthermore, the result of quantitative real-time polymerase chain reaction(qRT-PCR) showed that Cd-exposure reduced the mRNA expression level of NF-E2-related factor 2 (Nrf2), heme oxygenase (HO-1), NADPH quinone oxidoreductase 1 (NQO-1), and elevated the mRNA expression level of factor-kappaB (NF-κB) p65, inducible nitric oxide synthase (iNOS) in livers. However, all these changes were dose-dependently reversed by LIM. Overall, the present findings demonstrated that LIM have the hepatoprotective effect through antioxidant and anti-inflammatory responses in Cd-exposure mice.     

Rewiring yeast metabolism to synthesize products beyond ethanol

Saccharomyces cerevisiae, Baker's yeast, is the industrial workhorse for producing ethanol and the subject of substantial metabolic engineering research in both industry and academia. S. cerevisiae has been used to demonstrate production of a wide range of chemical products from glucose. However, in many cases, the demonstrations report titers and yields that fall below thresholds for industrial feasibility. Ethanol synthesis is a central part of S. cerevisiae metabolism, and redirecting flux to other products remains a barrier to industrialize strains for producing other molecules. Removing ethanol producing pathways leads to poor fitness, such as impaired growth on glucose. Here, we review metabolic engineering efforts aimed at restoring growth in non-ethanol producing strains with emphasis on relieving glucose repression associated with the Crabtree effect and rewiring metabolism to provide access to critical cellular building blocks. Substantial progress has been made in the past decade, but many opportunities for improvement remain.     

Is social coordination during escape flights a general phenomenon in birds?

Escape from predatory attack as a socially coordinated group is observed in many social animals, including birds, especially those in more open habitats where the group itself may be the only source of protection from an attacking predator. For many social birds, however, woody vegetative cover is the main refuge from attack, but such birds might nevertheless benefit from social coordination during escape flights to cover. Such benefits could reflect the confusion effect, selfish herd effect, or the simple dilution of risk. We examined this possibility of coordinated escape in mixed flocks of wintering passerellid sparrows (Passerellidae). These free-living birds fed in a patch of food flanked on opposite sides by two refuges composed of woody cover. Under such conditions, coordination in escape behavior should be expressed as a tendency to escape together as a group to the same cover location. Such behavior, however, was not the rule. During spontaneous flushes to cover, a group of escaping birds stayed together only when one cover location was clearly closer than the other. With cover equidistant from the food patch, escaping flocks tended to split about evenly between cover locations. Birds in close proximity prior to an escape flight did not show enhanced escape coordination, nor did those feeding at significant distances from protective cover. Evidence of escape coordination was observed in small groups (two–four birds), but even in such groups, flock splitting during escape was generally the rule. Flock splitting during attacks might reflect some sort of strategic decision-making process that lessens the risk of capture, but the most parsimonious explanation is that (all else equal) birds head for the nearest refuge, largely irrespective of the behavior of their flockmates. Our results thus provide little evidence of flock-wide social coordination during escape flights in cover-dependent birds.     

Colored plastic and metal leg bands do not affect survival of Piping Plover chicks

ABSTRACT Leg bands are commonly used to mark shorebird chicks as young as 1‐d old, but little is known about the possible impacts of bands on survival of prefledging shorebirds. We used a mark‐recapture framework to assess the impact of bands and banding‐related disturbance on prefledging survival in a federally endangered population of Piping Plovers (Charadrius melodus) breeding in the Great Lakes region from 2000 to 2008. We banded approximately 96% of all surviving chicks hatched prior to fledging, typically between 5 and 15 d of age. We used a multistate approach in program MARK whereby individuals contributed data as unbanded chicks before capture (N= 1073) and as banded chicks afterward (N= 780). The cumulative probability of surviving through 24 d of age was 0.63 and did not differ between banded and unbanded chicks. In addition, we found a positive effect of banding‐related disturbance on survival up to 3 d following banding (β= 0.60 CI: 0.17–1.02), possibly due to increased postbanding vigilance on the part of chicks and adults. Our results indicate that banding has no detrimental effect on survival of Piping Plover chicks prior to fledging and that current capture and banding methods are appropriate for this endangered species.     

The peninsula effect on bird species in native eucalypt forests in a wood production landscape in Australia

The peninsula effect – a decrease in species richness from the base to the tip of a peninsula – has been tested for a diverse range of taxa at continental and regional scales. We investigated the peninsula effect at a local scale by examining bird species occurrence in riparian strips (peninsulas) of native eucalypt forest within a radiata pine plantation in the Tumut region, south-eastern Australia. Peninsulas were elongated but 'blind' extensions of a core area of native eucalypt forest. Birds were surveyed by the area search method, within 1.0-ha quadrats established along peninsulas ( n =14), in October and November 2002. Data were analysed using generalized linear mixed models. A significant decrease in bird species richness from the base towards the tip of the peninsulas was observed. The proportion of large bird species recorded per quadrat showed a significant decrease from the base towards the tip of the peninsulas. This pattern was not observed for small birds. Several species were more abundant at the base of the peninsulas than away from the core area of eucalypt forest. The peninsula effect can occur locally in landscape mosaics. Factors leading to the observed patterns of species occurrence may be distinct from those proposed in investigations of the peninsula effect with a biogeographical (macroscale) context. In our microscale study, foraging incursions of individual birds from the core area of native forest through peninsulas were a major factor giving rise to higher bird species richness in the more basal portions of peninsulas.     

The effect of the leucopyrokinin analogue: [2-8]-leucopyrokinin on central opioid receptors in rats

The antinociceptive effect of intracerebroventricular injections of [2–8]-leucopyrokinin (LPK), a truncated leucopyrokinin analogue, was determined in rats, by means of a tail immersion test. We found a significant antinociceptive effect of three i.c.v. doses of [2–8]-LPK: 1, 5 and 10 nmol. Pre-treating animals with naloxone hydrochloride (1 mg/kg i.p.) completely blocked the effect of two high doses of [2–8]-LPK. To determine the sub-types of opioid receptors involved in [2–8]-leucopyrokinin-induced analgesia we injected specific blockers of μ-, δ- and κ-receptors namely, β-funaltrexamine hydrochloride, naltrindole hydrochloride and nor-binaltorphimine dihydrochloride, respectively, prior to [2–8]-leucopyrokinin at equimolar doses. We conclude that the antinociceptive effect of [2–8]-leucopyrokinin is mediated mainly by central μ- and δ-opioid receptors.     

Re‐approaching the small island effect

Aim To propose a new approach to the small island effect (SIE) and a simple mathematical procedure for the estimation of its upper limit. The main feature of the SIE is that below an upper size threshold an increase of species number with increase of area in small islands is not observed. Location Species richness patterns from different taxa and insular systems are analysed. Methods Sixteen different data sets from 12 studies are analysed. Path analysis was used for the estimation of the upper limit of the SIE. We studied each data set in order to detect whether there was a certain island size under which the direct effects of area were eliminated. This detection was carried out through the sequential exclusion of islands from the largest to the smallest. For the cases where an SIE was detected, a log‐log plot of species number against area is presented. The relationships between habitat diversity, species number and area are studied within the limits of the SIE. In previous studies only area was used for the detection of the SIE, whereas we also encompass habitat diversity, a parameter with well documented influence on species richness, especially at small scales. Results An SIE was detected in six out of the 16 studied cases. The upper limit of the SIE varies, depending on the characteristics of the taxon and the archipelago under study. In general, the values of the upper limit of the SIE calculated according to the approach undertaken in our study differ from the values calculated in previous studies. Main conclusions Although the classical species–area models have been used to estimate the upper limit of the SIE, we propose that the detection of this phenomenon should be undertaken independently from the species–area relationship, so that the net effects of area are calculated excluding the surrogate action of area on other variables, such as environmental heterogeneity. The SIE appears when and where area ceases to influence species richness directly. There are two distinct SIE patterns: (1) the classical SIE where both the direct and indirect effects of area are eliminated and (2) the cryptic SIE where area affects species richness indirectly. Our approach offers the opportunity of studying the different factors influencing biodiversity on small scales more accurately. The SIE cannot be considered a general pattern with fixed behaviour that can be described by the same model for different island groups and taxa. The SIE should be recognized as a genuine but idiosyncratic phenomenon.