100 research outputs found
Santon Diprenilasi dari Kayu Akar Garcinia tetranda Pierre
No full textGarcinia tetranda merupakan salah satu spesies dari famili Clusiaceae yang mengandung senyawa metabolit sekunder. Senyawa golongan santon telah berhasil diisolasi dari fraksi S ekstrak etil asetat kayu akar Garcinia tetranda Pierre. Senyawa golongan santon ini adalah α-mangostin 1 yang berupa padatan kuning dengan titik leleh 173-1740C. Metode isolasi yang digunakan yaitu Kromatografi Cair Vakum (KCV) menggunakan silika gel 60 GF254 dan dielusi dengan peningkatan kepolaran pelarut. Penentuan struktur senyawa dilakukan menggunakan analisis UV, IR, 1H dan 13C NMR, DEPT 135, korelasi HSQC dan HMBC serta dibandingkan dengan literatur
Scorpionfish adjust skin pattern contrast on different backgrounds
No full textThe two scorpionfish species Scorpaena maderensis and S. porcus are well camouflaged ambush predators that rapidly change body colouration to adjust to background colour in less than 1 min. We tested whether individuals of both species also adjust body pattern to that of the background. We placed fish on backgrounds of different pattern granularity and quantified the change in fish body pattern over 1 min. We used calibrated image analysis to analyse the patterns from the visual perspective of a prey fish species using a granularity (pattern energy) analysis and an image clustering approach. In our experiment, fish did not change their most contrasting pattern components as defined by the dominant marking size, but changed their average marking size. Moreover, fish responded with a change in pattern in contrast to the different experimental backgrounds, especially when compared to the acclimation phase. These results indicate that scorpionfish have one main pattern that can be adjusted by modulating its internal contrast. A reduction in pattern contrast could thereby improve background matching, while an increase could promote camouflage via disruptive colouration
Differences in childhood stress between Neanderthals and early modern humans as reflected by dental enamel growth disruptions
No full textNeanderthals’ lives were historically portrayed as highly stressful, shaped by constant pressures to survive in harsh ecological conditions, thus potentially contributing to their extinction. Recent work has challenged this interpretation, leaving the issue of stress among Paleolithic populations highly contested and warranting in-depth examination. Here, we analyze the frequency of dental enamel hypoplasia, a growth disruption indicator of early life stress, in the largest sample of Neanderthal and Upper Paleolithic dentitions investigated to date for these features. To track potential species-specific patterns in the ontogenetic distribution of childhood stress, we present the first comprehensive Bayesian modelling of the likelihood of occurrence of individual and matched enamel growth disruptions throughout ontogeny. Our findings support similar overall stress levels in both groups but reveal species-specific patterns in its ontogenetic distribution. While Neanderthal children faced increasing likelihoods of growth disruptions starting with the weaning process and culminating in intensity post-weaning, growth disruptions in Upper Paleolithic children were found to be limited around the period of weaning and substantially dropping after its expected completion. These results might, at least in part, reflect differences in childcare or other behavioral strategies between the two taxa, including those that were advantageous for modern humans’ long-term survival
Intercactions between Zinc and Copper in LEC rats an animal model of Wilson's disease
No full textThe effect of oral Zn treatment was studied in the liver and kidneys of 26 male Long-Evans Cinnamon (LEC) rats (mutant animals, 5 weeks old) in relation to both the interaction between Zn and Cu and the localisation and concentration of metallothionein (MT). Rats receiving 80 mg zinc acetate daily by gavage and control rats receiving no treatment were killed after 1 or 2 weeks. By immunohistochemical and analytical chemical techniques we revealed that treated rats had higher levels of NIT in the hepatic and renal cells compared to untreated ones. Tissue Zn concentrations were significantly higher in treated rats compared to untreated whereas Cu. concentrations decreased in the liver and kidneys as indicated by analytical chemical analyses. MT levels also decreased with treatment period. A histochemical procedure, obtained using autofluorescence of Cu-metallothioneins, confirms these findings: after 2 weeks, the signal decreased in both the liver and kidney sections. This gives a greater understanding of the mechanism of Cu metabolism in the two tissues considered. These results suggest that Zn acts both to compete for absorption on the luminal side of the intestinal epithelium and to induce the synthesis of MT
Optimizing flower fields as an effective farmland eco-scheme also during non-breeding
No full textThe Common Agricultural Policy (CAP) of the European Union implements several farmland eco-schemes, but most are considered ineffective in halting the population declines of farmland birds. Sown flower fields are among the few eco-scheme types that rate as clearly beneficial. Yet, current CAP regulations lack minimum criteria for flower fields to qualify as eco-scheme, and thus only partially exploit their potential biodiversity benefits. Earlier research on the attraction of farmland birds to different types of sown flower fields has focused on the breeding season. We know far less about relative use of these fields during the non-breeding season, when food limitation can become severe. We therefore compared the attractiveness of four flower field types in SW Germany to 17 bird species during autumn and winter. Based on replicate surveys on 75–168 fields, we analysed bird incidences across these four types, and in relation to vegetation structure and landscape features. Flower field types showed little variation in species richness, but striking differences in selection by particular species. Finches and tits were disproportionally abundant on fields in their first year since sowing, buntings and whinchat on fields in later successional stages. Most flower fields established under CAP greening regulations were ploughed between September and November in their sowing year. Therefore, such fields fail to support farmland birds and other wildlife during a critical phase in their annual cycle. Birds were consistently more abundant on larger fields with a differentiated vegetation structure. Flower fields along hedgerows and groves primarily attracted inhabitants of woodland ecotones, while farmland birds had higher incidences on fields embedded in open landscapes. Policy implications. EU member states currently revise their regulations for farmland eco-schemes, including sown flower fields. We propose minimum quality standards to assure that such fields effectively support farmland birds also during the non-breeding season. Standards include a minimum maintenance for two years, more diversified seed mixtures, field sizes exceeding 12 m width or 0.18 ha area, and local diversity in flower field placement relative to other landscape elements such as hedgerows
Visual modelling supports the potential for prey detection by means of diurnal active photolocation in a small cryptobenthic fish
No full textActive sensing has been well documented in animals that use echolocation and electrolocation. Active photolocation, or active sensing using light, has received much less attention, and only in bioluminescent nocturnal species. However, evidence has suggested the diurnal triplefin Tripterygion delaisi uses controlled iris radiance, termed ocular sparks, for prey detection. While this form of diurnal active photolocation was behaviourally described, a study exploring the physical process would provide compelling support for this mechanism. In this paper, we investigate the conditions under which diurnal active photolocation could assist T. delaisi in detecting potential prey. In the field, we sampled gammarids (genus Cheirocratus) and characterized the spectral properties of their eyes, which possess strong directional reflectors. In the laboratory, we quantified ocular sparks size and their angle-dependent radiance. Combined with environmental light measurements and known properties of the visual system of T. delaisi, we modeled diurnal active photolocation under various scenarios. Our results corroborate that diurnal active photolocation should help T. delaisi detect gammarids at distances relevant to foraging, 4.5 cm under favourable conditions and up to 2.5 cm under average conditions. To determine the prevalence of diurnal active photolocation for micro-prey, we encourage further theoretical and empirical work
A context analysis of bobbing and fin-flicking in a small marine benthic fish
No full textMost antipredator strategies increase survival of individuals by signaling to predators, by reducing the chances of being recognized as prey, or by bewildering a predator's perception. In fish, bobbing and fin-flicking are commonly considered as pursuit-deterrent behaviors that signal a predator that it has been detected and thus lost its surprise-attack advantage. Yet, very few studies assessed whether such behavioral traits are restricted to the visual presence of a predator. In this study, we used the yellow black-headed triplefin Tripterygion delaisi to investigate the association between these behaviors and the visual exposure to (a) a black scorpionfish predator (Scorpaena porcus), (b) a stone of a size similar to that of S. porcus, (c) a conspecific, and (d) a harmless heterospecific combtooth blenny (Parablennius sanguinolentus). We used a laboratory-controlled experiment with freshly caught fish designed to test for differences in visual cues only. Distance kept by the focal fish to each stimulus and frequency of bobbing and fin-flicking were recorded. Triplefins kept greater distance from the stimulus compartment when a scorpionfish predator was visible. Bobbing was more frequent in the visual presence of a scorpionfish, but also shown toward the other stimuli. However, fin flicks were equally abundant across all stimuli. Both behaviors decreased in frequency over time suggesting that triplefin become gradually comfortable in a nonchanging new environment. We discuss why bobbing and fin-flicking are not exclusive pursuit-deterrent behaviors in this species, and propose additional nonexclusive functions such as enhancing depth perception by parallax motion (bobbing) or signaling vigilance (fin-flicking)
Unexpected female preference for smaller males in the marbled goby Pomatoschistus marmoratus
No full textThe study tested the role of body size and of nest size in female mate choice in the marbled goby,
Pomatoschistus marmoratus. The results show a female preference for smaller males, supporting the
idea that smaller males may be preferred to larger ones in the absence of male–male competition. No
effect of nest size was detected, suggesting that other nest characteristics, beyond nest size, may be
implicated
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