Soil respiration in a Mediterranean oak forest at different developmental stages after coppicing

To assess the variation of soil respiration at different forest stages we measured it in a coppiced oak (Quercus cerris L.) chronosequence in central Italy during two campaigns, spanning 2 successive years, in four stands at different stages of the rotation: 1 year (S1), 5 years (S5), 10 years (S10) and 17 years (S17) after coppicing. The contribution of the different components of soil respiration flux (aboveground litter, belowground decomposition soil organic matter and root respiration) was estimated by a paired comparison of manipulative experiments between the recently coppiced stand (S1) and mature stand (S17). Ninety percent of soil respiration values were between 1.7 and 7.8 μmol m^?2 s^?1, with an overall mean (±SD) of 4.0±2.7 μmol m^?2 s^?1. Spatial variation of soil respiration was high (CV=44.9%), with a mean range (i.e. patch size) of 4.8±2.7 m, as estimated from a semivariance analysis. In the absence of limitation by soil moisture, soil respiration was related to soil temperature with the exponential Q₁₀ model (average Q₁₀=2.25). During summer, soil moisture constrained soil respiration and masked its dependence on soil temperature. Soil respiration declined over the years after coppicing. Assuming a linear decline with stand age, we estimated a reduction of 24% over a 20‐year‐rotation cycle. The response of soil respiration to temperature also changed with age of the stands: the Q₁₀ was estimated to decrease from 2.90 in S1 to 2.42 in S17, suggesting that different components or processes may be involved at different developmental stages. The contribution of heterotrophic respiration to total soil respiration flux was relatively larger in the young S1 stand than in the mature S17 stand.     

TIME INTENSITY PROFILES OF FLAVOR POTENTIATORS (MSG, IMP, GMP)

This research characterized the time-intensity (TI) profiles of monosodium glutamate (MSG), disodium 5'-inosinate (IMP), and disodium 5'-guanylate (GMP). Twenty subjects rated total taste intensity of single solutions of 2.5, 5 and 10 mM MSG, 0.63 and 2.5 mM IMP and GMP, and some of their mixtures, using the TI method. The profiles generated were atypical of other taste modalities. Time to maximum intensity waslong (16–20s), followed by a plateau at maximum intensity, and a persistent aftertaste (50–96s duration). Maximum intensities of the samples varied (p < 0.001), with mixtures of 10 and 5 mM MSG with 2.5 mM IMP or GMP yielding the highest intensities. Similar differences were found for total duration and area under the curve. These results indicate that flavor potentiators may increase total flavor during consumption. Synergism between flavor potentiators was demonstrated.     

3,4 Dichloroaniline-haemoglobin adducts in humans: preliminary data on agricultural workers exposed to propanil

Propanil is one of the major herbicides used on rice-paddies and is thought to produce adverse health effects through the action of its metabolite 3,4-dichloroaniline (3,4-DCA). T he feasibility of monitoring human exposure to propanil on the basis of 3,4-DCA adducts to haemoglobin (Hb) was investigated. We developed a method based on gas chromatography negative ion chemical ionization-mass spectrometry (NICI-GC-MS) to quantify 3,4-DCA released from human Hb after alkaline hydrolysis of the protein. 3,4-DCA-Hb adducts were identified in agricultural workers exposed to propanil and were detectable even 4 months after the last herbicide application. Urine samples collected at the same time had no measurable level of 3,4-DCA. 3,4-DCA-Hb adducts might be useful for monitoring human exposure to 3,4-DCA from agricultural sources.     

Melanins in Physiological Conditions Protect Against Lipoperoxidation. A Study on Albino and Pigmented Xenopus

The susceptibility to lipoperoxidation in liver of albino and pigmented Xenopus laevis Daudin, has been studied. Albino Xenopus liver was richer in polyunsaturated fatty acids (PUFAs) than the pigmented one; moreover, it was also richer in mitochondrial superoxide dismutase (MnSOD) and in reduced glutathione (GSH). The thiobarbituric acid-reactive substances (TBARS) values were more abundant in the albino tissue compared to the pigmented tissue both during spontaneous and Fe⁺⁺ induced lipoperoxidation. Therefore, when isolated and purified melanin, in physiological quantities, was added to albino tissue, the TBARS values drastically decreased. Thus, melanin, in our experimental conditions, protects the albino tissue even more than SOD and GSH do. Melanin, in our opinion, acts as an antioxidant, because it is able to scavenge O₂^?.     

3,4 Dichloroaniline-haemoglobin adducts in humans: preliminary data on agricultural workers exposed to propanil

Propanil is one of the major herbicides used on rice-paddies and is thought to produce adverse health effects through the action of its metabolite 3,4-dichloroaniline (3,4-DCA). T he feasibility of monitoring human exposure to propanil on the basis of 3,4-DCA adducts to haemoglobin (Hb) was investigated. We developed a method based on gas chromatography negative ion chemical ionization-mass spectrometry (NICI-GC-MS) to quantify 3,4-DCA released from human Hb after alkaline hydrolysis of the protein. 3,4-DCA-Hb adducts were identified in agricultural workers exposed to propanil and were detectable even 4 months after the last herbicide application. Urine samples collected at the same time had no measurable level of 3,4-DCA. 3,4-DCA-Hb adducts might be useful for monitoring human exposure to 3,4-DCA from agricultural sources.     

Testing the regeneration niche hypothesis with Gesneriaceae (tribe Sinningiae) in Brazil: Implications for the conservation of rare species

The germination requirements of sexually reproducing plants are regulated by environmental factors such as temperature. Those factors acting at the germination phase are part of the regeneration niche, which is fundamental in the processes that contribute to habitat suitability and geographic distribution. We tested the hypothesis that rarity is associated with regeneration niche in three species of plants in the family Gesneriaceae (tribe Sinningieae), Sinningia rupicola (Mart.) Wiehler, Paliavana sericiflora Benth and Sinningia allagophylla (Mart.) Wiehler, which vary in their distribution and habitat specificity but share a small zone of sympatry in rocky fields south of Belo Horizonte in Minas Gerais, Brazil. The regeneration niche was tested using a seed germination experiment under controlled light conditions at seven fixed temperatures (10–40°C at 5°C intervals). Each of the three species germinated differently at the various temperatures. The species with the smallest geographic range, S. rupicola, also had the most restricted germination: germination peaked at 15°C when relatively few seeds germinated (45%), and even fewer germinated at other temperatures. The regeneration niche was wider in P. sericiflora and wider still in S. allagophylla, with germination greater than 90% between 15–25°C and greater than 80% between 15–30°C, respectively. Our germination results provide qualified support for the hypothesis of correlation of the regeneration niche with geographic distribution of related plant taxa, with important conservation implications for rare and endangered species.     

加州Santa Monica海湾鳍足类的生态学

研究了加州Santa Monica海湾鳍足类的生态学.从1997-2007年乘船调查了277次,发现海狮(Zalophus californianus)是最常见的动物(89%,见到的次数为1393次),其次是港海豹(Phoca vitulina richardsi,8%,n=131)和北象海豹(Mirounga angustirostris,1%,n=15).在29%的遇见次数(观察到瓶海豚205次)中,发现海狮(偶尔也发现港海豹)与瓶鼻海豚集群(Tursiops truncatus);短喙真海豚(Delphinus delphis)与长喙真海豚(D.capensis)在53% 的遇见次数(遇见真海豚次数n=155)中,发现短喙真海豚(Delphinus delphis)与长喙真海豚(D.capensis)集群;一般在沿岸水域(离岸边距离<500 m)见到海狮和港海豹,但在整个海湾也能见到,表现出这两个物种对海底峡谷的偏爱.北象海豹仅见于近海,主要在海底峡谷附近. 经常看到海狮、港海豹和北象海豹游动(50%,n=728)、进行热调节(14%,n=205)、以及取食(3.2%,n=47),但几乎见不到有社会性活动(0.21%,n=3).     

Evidence of a complex phylogeographic structure in the common dormouse,Muscardinus avellanarius (Rodentia: Gliridae)

This is the first mitochondrial phylogeography of the common dormouse, Muscardinus avellanarius (Linnaeus, 1758), a hibernating rodent strictly protected in Europe (Habitat Directive, annex IV; Bern Convention, annex III). The 84 individuals of M. avellanarius, sampled throughout the distributional range of the species, have been sequenced at the mitochondrial DNA gene (cytochrome b, 704 base pairs). The results revealed two highly divergent lineages, with an ancient separation around 7.7 Mya and a genetic divergence of 7.7%. Lineage 1 occurs in Western Europe (France, Belgium, and Switzerland) and Italy, and lineage 2 occurs in Central–Northern Europe (Poland, Germany, Latvia, and Lithuania), on the Balkan Peninsula, and in Turkey. Furthermore, these two lineages are subdivided into five sublineages genetically isolated with a strong geographical association. Therefore, lineage 1 branches into two further sublineages (Western European and Italian), whereas lineage 2 contained three sublineages (Central–Northern European, Turkish, and Balkan). We observed low genetic diversity within the sublineages, in contrast to the significant level of genetic differentiation between them. The understanding of genetic population structure is essential for identifying units to be conserved. Therefore, these results may have important implications for M. avellanarius conservation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 648–664.