Effect of copper sulfate on experimental atherosclerosis

Serum copper concentration increases significantly (p<0.01) in rats with experimental atherosclerosis compared to a control group. The serum zinc, the zinc, and copper concentration in abdominal aorta and in liver decreases significantly (p<0.05) compared to the control group. Administration of copper sulfate for 100 d in these animals induces a significant increase of serum copper (p<0.01), decrease of serum cholesterol (p<0.05) and increase of liver copper concentration as compared with the group fed only a high cholesterol diet. In the aorta of these animals the copper concentration increases and edema and lipid infiltration are considerably less than in the group of animals fed only a high lipid diet.     

人肝刺激因子对大鼠实验性慢性肝损伤的保护作用

从健康孕妇水囊引产４─６个月龄的胎儿取肝,采用ＬａＢｒｅｃｑｕｅ方法提取人肝刺激因子（ｈＨＳＳ）。经３Ｈ－胸腺嘧啶核苷参入肝ＤＮＡ法测定其生物活性。表明此ｈＨＳＳ可刺激肝细胞ＤＮＡ合成。采用皮下注射ＣＣｌ４和饮用１０％乙醇来制备慢性肝损伤动物模型,观察了ｈＨＳＳ的保护肝脏作用。结果表明：ｈＨＳＳ可使ＣＣｌ４－乙醇所致慢性肝损伤大鼠的死亡率、血清谷丙转氨酶水平、肝组织中羟脯氨酸含量的升高以及肝组织中丙二醛的含量降低。肝组织切片表明：ｈＨＳＳ能减轻肝组织的损伤程度,促进肝细胞再生,并能明显防止肝纤维化的形成和发展。可见,ｈＨＳＳ对ＣＣｌ４－乙醇所致的慢性肝损伤大鼠有明显的保护作用,其机制可能与促进肝细胞再生及抑制肝细胞膜的脂质过氧化有关。     

Effect of dimethylglycine and trimethylglycine (Betaine) on the response of Atlantic salmon (Salmo salar L.) smolts to experimental Vibrio anguillarum infection

Atlantic salmon (Salmo salar L.) were fed on a control diet or experimental diets containing betaine (15 mg g^-1) or dimethylglycine (DMG, I mg g^-1 or 5 mg g^-1). After 10 weeks of feeding, resistance to infection was assessed following inoculation with Vibrio anguillarum. Total blood and differential leucocyte counts were made, and plasma lysozyme and ceruloplasmin were assayed as non-specific humoral factors. The mortality during the bacterial exposure was of the same magnitude in all feeding groups. Betaine or DMG had no effect on the 'basal' levels of plasma total protein, lysozyme or ceruloplasmin, but 3 days postinjection the lysozyme and ceruloplasmin levels were higher in the control group compared with the experimental groups. In both DMG groups, the lymphocyte response took place 1-2 weeks earlier than in the control or betaine supplemented group indicating that DMG has an immunomodulating effect on salmon.     

Topcats and underdogs: intraguild interactions among three apex carnivores across Asia's forestscapes

Intraguild interactions among carnivores have long held the fascination of ecologists. Ranging from competition to facilitation and coexistence, these interactions and their complex interplay influence everything from species persistence to ecosystem functioning. Yet, the patterns and pathways of such interactions are far from understood in tropical forest systems, particularly across countries in the Global South. Here, we examined the determinants and consequences of competitive interactions between dholes Cuon alpinus and the two large felids (leopards Panthera pardus and tigers Panthera tigris) with which they most commonly co-occur across Asia. Using a combination of traditional and novel data sources (N = 118), we integrate information from spatial, temporal, and dietary niche dimensions. These three species have faced catastrophic declines in their extent of co-occurrence over the past century; most of their source populations are now confined to Protected Areas. Analysis of dyadic interactions between species pairs showed a clear social hierarchy. Tigers were dominant over dholes, although pack strength in dholes helped ameliorate some of these effects; leopards were subordinate to dholes. Population-level spatio-temporal interactions assessed at 25 locations across Asia did not show a clear pattern of overlap or avoidance between species pairs. Diet-profile assessments indicated that wild ungulate biomass consumption by tigers was highest, while leopards consumed more primate and livestock prey as compared to their co-predators. In terms of prey offtake (ratio of wild prey biomass consumed to biomass available), the three species together harvested 0.4–30.2% of available prey, with the highest offtake recorded from the location where the carnivores reach very high densities. When re-examined in the context of prey availability and offtake, locations with low wild prey availability showed spatial avoidance and temporal overlap among the carnivore pairs, and locations with high wild prey availability showed spatial overlap and temporal segregation. Based on these observations, we make predictions for 40 Protected Areas in India where temporally synchronous estimates of predator and prey densities are available. We expect that low prey availability will lead to higher competition, and in extreme cases, to the complete exclusion of one or more species. In Protected Areas with high prey availability, we expect intraguild coexistence and conspecific competition among carnivores, with spill-over to forest-edge habitats and subsequent prey-switching to livestock. We stress that dhole–leopard–tiger co-occurrence across their range is facilitated through an intricate yet fragile balance between prey availability, and intraguild and conspecific competition. Data gaps and limitations notwithstanding, our study shows how insights from fundamental ecology can be of immense utility for applied aspects like large predator conservation and management of human–carnivore interactions. Our findings also highlight potential avenues for future research on tropical carnivores that can broaden current understanding of intraguild competition in forest systems of Asia and beyond.     

Disentangling the historical routes to community assembly in the global epicentre of biodiversity

Aim

The exceptional turnover in biota with elevation and number of species coexisting at any elevation makes tropical mountains hotspots of biodiversity. However, understanding the historical processes through which species arising in geographical isolation (i.e. allopatry) assemble along the same mountain slope (i.e. sympatry) remains a major challenge. Multiple models have been proposed including (1) the sorting of already elevationally divergent species, (2) the displacement of elevation upon secondary contact, potentially followed by convergence, or (3) elevational conservatism, in which ancestral elevational ranges are retained. However, the relative contribution of these processes to generating patterns of elevational overlap and turnover is unknown.

Location

Tropical mountains of Central- and South-America.

Time Period

The last 12 myr.

Major Taxa Studied

Birds.

Methods

We collate a dataset of 165 avian sister pairs containing estimates of phylogenetic age, geographical and regional elevational range overlap. We develop a framework based on continuous-time Markov models to infer the relative frequency of different historical pathways in explaining present-day overlap and turnover of sympatric species along elevational gradients.

Results

We show that turnover of closely related bird species across elevation can predominantly be explained by displacement of elevation ranges upon contact (81%) rather than elevational divergence in allopatry (19%). In contrast, overlap along elevation gradients is primarily (88%) explained by conservatism of elevational ranges rather than displacement followed by elevational expansion (12%).

Main Conclusions

Bird communities across elevation gradients are assembled through a mix of processes, including the sorting, displacement and conservatism of species elevation ranges. The dominant role of conservatism in explaining co-occurrence of species on mountain slopes rejects more complex scenarios requiring displacement followed by expansion. The ability of closely related species to coexist without elevational divergence provides a direct and faster pathway to sympatry and helps explain the exceptional species richness of tropical mountains.     

Interactions between the toxicity of the heavy metals cadmium,copper, zinc in combinations and the detoxifying role of calcium in the brown algaCystoseira barbata

The toxicity of three heavy metals, Cd, Cu and Zn, and the detoxifying role of Ca have been studied for the brown algaCystoseira barbata formaaurentia after a 4-week laboratory culture. The experimental design was based upon a complete factorial design 2^k, which seems to be the first time it has been used in algal physiology. It was demonstrated that these three elements, applied jointly, act on weight-growth, chlorophyll a, c and carotenoid synthesis and Cd, Cu and Zn uptake. Cd and Zn act in synergy or in antagony, depending on their exogenous concentrations, on chlorophyll a and on carotenoid synthesis. Zn is antagonistic towards Cd and Cu on weight-growth in the combination Cd-Cu-Zn. From different element combinations, the protective role of Ca appears evident on weight-growth (Cd-Zn-Ca and Cu-Ca), chlorophyll a (Cd-Cu-Ca and Cu-Zn-Ca), chlorophyll c (Cd-Ca), carotenoid synthesis (Cd-Cu-Ca and Cu-Zn-Ca), Cd and Cu uptake (Cd-Cu-Ca) and Zn uptake (Cu-Zn-Ca). This role is confirmed by cytological investigations. This is apparently the first report concerning a Ca interaction with toxicity of heavy metals applied in combinations. However, the mechanisms of tolerance remain unknown.     

Environmental conditions during glycerol bioconversion affect 3-hydroxypropionic acid bioproduction by Limosilactobacillus reuteri DSM 17938

3-Hydroxypropionic acid (3-HP) is a platform molecule whose biological production was carried out by the bacterium Limosilactobacillus reuteri according to a two-step process: first, a growth phase in batch mode on glucose, then a glycerol bioconversion into 3-HP in fed-batch mode. With the objective of improving 3-HP bioproduction, this study aimed at defining the operating conditions during the bioconversion phase that increases the bioproduction performance. A central composite rotatable design allowed testing various pH levels and specific glycerol feeding rates. By establishing response surfaces, optimal conditions have been identified that were different depending on the considered output variable (final 3-HP quantity, 3-HP production yield and production rate). Of them, 3-HP final quantity and 3-HP production yield were maximized at pH 6.0 and at specific glycerol feeding rates of 60 and 55 mg_gly g_CDW⁻¹ h⁻¹, respectively. The specific 3-HP production rate was the highest at the upper limit of the specific substrate feeding rate (80 mg_gly g_CDW⁻¹ h⁻¹) but was not affected by the pH. An additional experiment was carried out at pH 6.0 and a specific glycerol feeding rate of 80 mg_gly g_CDW⁻¹ h⁻¹ to validate the previous observations. In conclusion, the results showed a significant improvement of 3-HP concentration by 13%, of specific production rate by 34% and of 3-HP volumetric productivity by 39%, as compared to the initial values.     

一种模拟高原低氧复合冷冻的简易动物实验舱

以氮稀释法使舱内氧含量维持实验模拟高度,以普通冰箱制冷系统维持舱内恒温,以多功能低温浴槽作为致冻装置。该舱可于２０ｍｉｎ内升至模拟６０００ｍ高度,每次可供１６只大鼠作高原冻伤实验。实验期间高度恒定于６０００±２００ｍ,舱温２１±１℃。相对湿度５５％±１５％,冷冻液－２５．０±０．５℃。该舱结构简单、使用方便,可在实验室中模拟高原条件进行冷冻实验研究。由于不使用人体减压舱,不仅避免了减压缺氧对实验人员的不利影响,也减少了实验消耗。     

多元方差分析中的单一自由度独立比较

本文根据一元方差分析的单一自由度比较原理提出了多元方差分析中的单一自由度比较方法,以用于各种平衡试验设计中具多个变量的处理间多重比较．     

Influence of helping and breeding experience on reproductive performance in the Seychelles warbler: a translocation experiment

Reproductive success of the cooperative breeding Seychelleswarbler (Acrocephalus sechellensis) increases with age. Thisage effect is not due to differential survival or increasedreproductive effort, but to accumulated helping and breedingexperience. In their first year of breeding, reproductive performanceof inexperienced warblers with neither helping nor breedingexperience was significandy lower than that of warblers of thesame age with either previous helping or breeding experience.Reproductive performance was the same for primiparae with helpingexperience and for birds with breeding experience. Female primiparaewith helping experience or breeding experience built betternests and spent more time incubating than inexperienced females,which led to increased hatching success. Male primiparae withhelping experience or males with breeding experience guardedthe clutch better than inexperienced males, which led to reducedegg predation. Even-aged warblers with different previous experienceswere transferred to unoccupied islands, where birds startedbreeding immediately in high-quality territories. The experimentshowed that birds with helping experience produced their firstfledgling as fast as experienced breeders, and significandyfaster than inexperienced birds. Breeding performance did notimprove further with experience after the first successful breedingattempt. Only birds with previous breeding experience who pairedwith inexperienced birds, were likely to change mate. The otherpair combinations remained stable. Thus, primiparous birds withhelping experience have greater lifetime reproductive successthan inexperienced primiparae of the same age. This experimentshows that helping behavior has not only been selected for inthe context of promoting an individual's indirect fitness, butalso in the context of gaining helping experience which translatesinto improved reproductive success when a helper becomes a breeder.[Behav Ecol 7: 326-333 (1996)]