How costly is clutch formation in the Audouin's Gull Larus audouinii?

During the Audouin's Gull's breeding season at the Ebro Delta in 1993, 24 fresh eggs from eight three-egg clutches (modal clutch-size) were collected at the peak of the laying period. Eggs were processed to obtain formalin-fixed yolks, which were halved and stained using the potassium dichromate method. Digitized images of the yolks were examined to assess the daily rates of yolk deposition. We used these data in combination with egg compositional analysis to build a model of energy demands during the formation of an average clutch in Audouin's Gull. To show how the different parameters of clutch formation affect the daily energy investment peak, we performed a simulation analysis in which the rapid yolk development (RYD) period, the follicle triggering interval (FTI), the laying interval (LI) and the albumen synthesis period (ASP) were allowed to vary simultaneously. In our sample, the mean RYD period was seven days with a range from six to eight days. There were no significant differences in yolk volume among eggs in a clutch, but albumen volume was significantly smaller in third eggs. According to our model the albumen synthesis of the a-egg coincides with the energy demand peak for clutch formation. This peak represents an increase by ca. 42% in female energy requirements. Values obtained from the simulation analysis showed that only the ASP of the a-egg and the RYD durations of the second and third follicles produced noticeable reductions in peak energy investment. We predict that in gulls, whose laying intervals seem to be kept constant, significant increases of the durations of the RYD periods of second and third eggs, or even significant reductions of yolk size of these eggs, may operate simultaneously to match the energy demands during clutch formation to the prevailing food conditions.     

Phrasal Paraphrase Based Question Reformulation for Archived Question Retrieval

Lexical gap in cQA search, resulted by the variability of languages, has been recognized as an important and widespread phenomenon. To address the problem, this paper presents a question reformulation scheme to enhance the question retrieval model by fully exploring the intelligence of paraphrase in phrase-level. It compensates for the existing paraphrasing research in a suitable granularity, which either falls into fine-grained lexical-level or coarse-grained sentence-level. Given a question in natural language, our scheme first detects the involved key-phrases by jointly integrating the corpus-dependent knowledge and question-aware cues. Next, it automatically extracts the paraphrases for each identified key-phrase utilizing multiple online translation engines, and then selects the most relevant reformulations from a large group of question rewrites, which is formed by full permutation and combination of the generated paraphrases. Extensive evaluations on a real world data set demonstrate that our model is able to characterize the complex questions and achieves promising performance as compared to the state-of-the-art methods.     

A Novel Hyaluronidase Produced by Bacillus sp. A50

Hyaluronidases are a family of enzymes that degrade hyaluronic acid (hyaluronan, HA) and widely used in many fields. A hyaluronidase producing bacteria strain was screened from the air. 16S ribosomal DNA (16S rDNA) analysis indicated that the strain belonged to the genus Bacillus, and the strain was named as Bacillus sp. A50. This is the first report of a hyaluronidase from Bacillus, which yields unsaturated oligosaccharides as product like other microbial hyaluronate lyases. Under optimized conditions, the yield of hyaluronidase from Bacillus sp. A50 could reach up to 1.5×10⁴ U/mL, suggesting that strain A50 is a good producer of hyaluronidase. The hyaluronidase (HAase-B) was isolated and purified from the bacterial culture, with a specific activity of 1.02×10⁶ U/mg protein and a yield of 25.38%. The optimal temperature and pH of HAase-B were 44°C and pH 6.5, respectively. It was stable at pH 5–6 and at a temperature lower than 45°C. The enzymatic activity could be enhanced by Ca²⁺, Mg²⁺, or Ni²⁺, and inhibited by Zn²⁺, Cu²⁺, EDTA, ethylene glycol tetraacetic acid (EGTA), deferoxamine mesylate salt (DFO), triton X-100, Tween 80, or SDS at different levels. Kinetic measurements of HAase-B towards HA gave a Michaelis constant (K _m) of 0.02 mg/mL, and a maximum velocity (V _max) of 0.27 A ₂₃₂/min. HAase-B also showed activity towards chondroitin sulfate A (CSA) with the kinetic parameters, K _m and V _max, 12.30 mg/mL and 0.20 A ₂₃₂/min respectively. Meanwhile, according to the sequences of genomic DNA and HAase-B’s part peptides, a 3,324-bp gene encoding HAase-B was obtained.     

Turnover of plant lineages shapes herbivore phylogenetic beta diversity along ecological gradients

Understanding drivers of biodiversity patterns is of prime importance in this era of severe environmental crisis. More diverse plant communities have been postulated to represent a larger functional trait‐space, more likely to sustain a diverse assembly of herbivore species. Here, we expand this hypothesis to integrate environmental, functional and phylogenetic variation of plant communities as factors explaining the diversity of lepidopteran assemblages along elevation gradients in the Swiss Western Alps. According to expectations, we found that the association between butterflies and their host plants is highly phylogenetically structured. Multiple regression analyses showed the combined effect of climate, functional traits and phylogenetic diversity in structuring butterfly communities. Furthermore, we provide the first evidence that plant phylogenetic beta diversity is the major driver explaining butterfly phylogenetic beta diversity. Along ecological gradients, the bottom up control of herbivore diversity is thus driven by phylogenetically structured turnover of plant traits as well as environmental variables.     

Insulin-induced expression of human heat-shock protein gene hsp70

In human hepatoma cell line Hep3B/T2, the human heat-shock-inducible gene hsp70 could be induced by insulin. The dose-dependent insulin effect correlates very well with the dissociation constant of the insulin receptor, indicating that the insulin effect is mediated by the insulin receptor. The expression of hsp70 gene was neither significantly induced by growth factors of epidermal and platelet-derived growth factors, nor by tumor promoter, calcium ionophore, cAMP, and glucocorticoids. These results indicate that the induction of expression of hsp70 gene by insulin is very specific and not cell cycle-related. Furthermore, the insulin-induced expression of hsp70 gene is transient, occurring specifically from 4 to 8 h after insulin addition.     

Enhanced viability of Lactobacillus reuteri for probiotics production in mixed solid-state fermentation in the presence of Bacillus subtilis

In order to develop a multi-microbe probiotic preparation of Lactobacillus reuteri G8-5 and Bacillus subtilis MA139 in solid-state fermentation, a series of parameters were optimized sequentially in shake flask culture. The effect of supplementation of B. subtilis MA139 as starters on the viability of L. reuteri G8-5 was also explored. The results showed that the optimized process was as follows: water content, 50 %; initial pH of diluted molasses, 6.5; inocula volume, 2 %; flask dry contents, 30～35 g/250 g without sterilization; and fermentation time, 2 days. The multi-microbial preparations finally provided the maximum concentration of Lactobacillus of about 9.01?±?0.15 log CFU/g and spores of Bacillus of about 10.30?±?0.08 log CFU/g. Compared with pure fermentation of L. reuteri G8-5, significantly high viable cells, low value of pH, and reducing sugar in solid substrates were achieved in mixed fermentation in the presence of B. subtilis MA139 (P?<?0.05). Meanwhile, the mixed fermentation showed the significantly higher antimicrobial activity against E. coli K88 (P?<?0.05). Based on the overall results, the optimized process enhanced the production of multi-microbe probiotics in solid-state fermentation with low cost. Moreover, the viability of L. reuteri G8-5 could be significantly enhanced in the presence of B. subtilis MA139 in solid-state fermentation, which favored the production of probiotics for animal use.