Size-dependent predation risk in tree-feeding insects with different colouration strategies: a field experiment

1. Body size is positively correlated with fecundity in various animals, but the factors that counterbalance the resulting selection pressure towards large size are difficult to establish. Positively size-dependent predation risk has been proposed as a selective factor potentially capable of balancing the fecundity advantage of large size.
2. To construct optimality models of insect body size, realistic estimates of size-dependent predation rates are necessary. Moreover, prey traits such as colouration should be considered, as they may substantially alter the relationship between body size and mortality risk.
3. To quantify mortality patterns, we conducted field experiments in which we exposed cryptic and conspicuous artificial larvae of different sizes to bird predators, and recorded the incidence of bird attacks.
4. The average daily mortality rate was estimated to vary between 4% and 10%. In both cryptic and conspicuous larvae, predation risk increased with prey size, but the increase tended to be steeper in the conspicuous group. No main effect of colour type was found. All the quantitative relationships were reasonably consistent across replicates.
5. Our results suggest that the size dependence of mortality risk in insect prey is primarily determined by the probability of being detected by a predator rather than by a size-dependent warning effect associated with conspicuous colouration. Our results therefore imply that warningly coloured insects do not necessarily benefit more than the cryptic species from large body size, as has been previously suggested.     

Strategies to improve fertility in Bos indicus postpubertal heifers and nonlactating cows submitted to fixed-time artificial insemination

Two experiments were designed to evaluate strategies to increase fertility of Bos indicus postpubertal heifers and nonlactating cows submitted to a fixed-time artificial insemination (TAI) protocol consisting of an intravaginal device containing 1.9 g of progesterone (CIDR) insertion + estradiol benzoate on Day 0, CIDR withdrawal + estradiol cypionate on Day 9, and TAI on Day 11. In Experiment 1, heifers (n = 1153) received a new or an 18-d previously used CIDR and, on Day 9, prostaglandin F_2α (PGF_2α) + 0, 200, or 300 IU equine chorionic gonadotropin (eCG). Heifers treated with a new CIDR had greater (least squares means ± SEM) serum concentration of progesterone on Day 9 (3.06 ± 0.09 ng/mL vs. 2.53 ± 0.09 ng/mL; P < 0.05) and a smaller follicle at TAI (11.61 ± 0.11 mm vs. 12.05 ± 0.12 mm; P < 0.05). Heifers with smaller follicles at TAI had lesser serum progesterone concentrations on Day 18 and reduced rates of ovulation, conception, and pregnancy (P < 0.05). Treatment with eCG improved (P < 0.05) follicle diameter at TAI (11.50 ± 0.10 mm, 11.90 ± 0.11 mm, and 12.00 ± 0.10 mm for 0, 100, and 200 IU, respectively), serum progesterone concentration on Day 18 (2.77 ± 0.11 ng/mL, 3.81 ± 0.11 ng/mL, and 4.87 ± 0.11 ng/mL), and rates of ovulation (83.8%, 88.5%, and 94.3%) and pregnancy (41.3%, 47.0%, and 46.7%). In Experiment 2, nonlactating Nelore cows (n = 702) received PGF_2α treatment on Days 7 or 9 and, on Day 9, 0 or 300 IU eCG. Cows receiving PGF_2α on Day 7 had lesser serum progesterone concentrations on Day 9 (3.05 ± 0.21 ng/mL vs. 4.58 ± 0.21 ng/mL; P < 0.05), a larger follicle at TAI (11.54 ± 0.21 mm vs. 10.84 ± 0.21 mm; P < 0.05), and improved (P < 0.05) rates of ovulation (85.4% vs. 77.0%), conception (60.9% vs. 47.2%), and pregnancy (52.0% vs. 36.4%). Treatment with eCG improved (P < 0.05) serum progesterone concentration on Day 18 (3.24 ± 0.14 ng/mL vs. 4.55 ± 0.14 ng/mL) and the rates of ovulation (72.4% vs. 90.0%) and pregnancy (37.5% vs. 50.8%). In conclusion, giving PGF_2α earlier in the protocol in nonlactating cows and eCG treatment in postpubertal heifers and nonlactating cows improved fertility in response to a TAI (progesterone + estradiol) protocol.     

Evaluation of cell surface-displayed protein stability against simulated gastric fluid

A molecular display technology that uses the displayed proteins on cell surfaces has many applications in microbiology and molecular biology. Here, we describe the resistance of displayed proteins to proteases using simulated gastric fluid (SGF), which included pepsin at pH 2. The displayed β-glucosidase resisted pepsin digestion compared with secreted, free β-glucosidase. In SDS-PAGE and Western blotting analysis, the secreted β-glucosidase was immediately digested within 1 min following SGF treatment, although the displayed β-glucosidase was stable for more than 60 min following SGF treatment. In addition, the residual activity of secreted β-glucosidase was completely destroyed after 10 min SGF treatment. However, displayed β-glucosidase retained 14% of its residual activity following the same treatment. These results clearly show that cell surface display technology using enzymes can reveal the protease resistance of a protein of interest under various conditions.     

Clarified cashew apple juice as alternative raw material for biosurfactant production by Bacillus subtilis in a batch bioreactor

Clarified cashew apple juice was evaluated as carbon source for surfactin production by Bacillus subtilis LAMI005 isolated from the tank of chlorination at the Wastewater Treatment Plant on Campus do Pici (WWTP-PICI) in the Federal University of Ceará, Brazil. The highest surfactin concentration using clarified cashew apple juice (CCAJ) supplemented with mineral medium (MM-CCAJ) was 123 mg/L, achieved after 48 h of fermentation. Almost 2-fold less than the amount produced using mineral medium supplemented with 10 g/L of glucose and 8.7 g/L of fructose (MM-GF). However, critical micelle concentration of the biosurfactants produced using MM-CCAJ was 2.5-fold lower than the one produced using MM-GF, which indicates it is a more efficient biosurfactant. Surface tension decreased from 38.50 ± 0.0 to 29.00 ± 0.0 dyne/cm when B. subtilis was grown on MM-CCAJ media (24.68% of reduction on surface tension) and remained constant up to 72 h. Emulsification index was 51.15 and 66.70% using soybean oil and kerosene, respectively. Surfactin produced in MM-CCAJ showed an emulsifying activity of, respectively, 1.75 and 2.3 U when n-hexadecane or soybean oil was tested. However, when mineral medium supplemented with 10 g/L of glucose (MM-G) was used an emulsifying activity of 2.0 and 1.75 U, with n-hexadecane and soybean oil, respectively, was obtained. These results indicate that it is feasible to produce surfactin from CCAJ, a renewable and low-cost carbon source.     

3种淡水肉食性鱼类胰脏及胰液导管系统的组织学比较

应用解剖学和组织学技术对翘嘴鲌Culter alburnus、大鳍鳠Mystus macropterus和斑鳜Siniperca scherzeri的胰脏进行观察.结果表明,翘嘴鲌和大鳍鳠胰脏为弥漫混合型(suffusion-mix type),斑鳜为散布致密型(disperse-dense type).翘嘴鲌和大鳍鳠胰脏被膜较薄,厚度分别为4.33 μm±1.12 μm和7.24 μm±3.69 μm,而斑鳜胰脏被膜较厚,为50.96 μm±11.02 μm.翘嘴鲌胰小叶不明显,大鳍鳠非常明显,斑鳜比较明显.3种鱼胰腺细胞体积较大,核仁大而明显,细胞质内均有大量深色网络状或羽毛状结构和颗粒物质分布;胰脏内胰液运输管道均由闰管、小叶内导管、小叶间导管和集合导管组成,其中集合导管结构比较典型,管壁分为3层,即内层由单层柱状上皮和固有膜组成,中层由平滑肌细胞组成,外层由结缔组织组成.翘嘴鲌胰岛相对较小和分散,单位面积数量较少;大鳍鳠胰岛相对较大和分散,单位面积数量也较少;斑鳜胰岛最大,相对集中,单位面积数量较多.3种鱼胰岛外均被结缔组织被膜,结缔组织伸入胰岛内将胰岛细胞分隔为细胞小团或细胞索;G-醛复红染色仅观察到A细胞和B细胞,胞质颗粒分别被染成紫红色和黄色;B细胞占优势.     

人工纯林和混交林中南酸枣木材解剖特性的比较分析

对林龄为25 a的南酸枣[Choerospondias axillaris (Roxb. ) Burtt et Hill]纯林、南酸枣-马尾松(Pinus massoniana Lamb. )混交林和南酸枣-杉木[Cunninghamia lanceolata (Lamb. ) Hook. ]混交林中南酸枣木材的解剖特性进行了比较分析.测定结果表明,在25 a的树龄内,南酸枣-马尾松混交林、南酸枣-杉木混交林和南酸枣纯林中南酸枣木材纤维的长度分别为0.843～1.401、0.858～1.489和0.873～1.347 mm,宽度分别为19.28～23.58、19.34～22.34和19.76～25.26 μm,长宽比分别为39.70～62.04、39.20～63.96和40.60～59.34;随树龄的增加,纯林和混交林中南酸枣木材纤维的长度、宽度及长宽比均逐渐增加,且不同林分间的差异逐渐达到显著水平,并以南酸枣-杉木混交林中南酸枣木材纤维的长度和长宽比最大、宽度最小.3种林分中南酸枣木材的导管组织比量、纤维组织比量和木射线组织比量分别为16.1%～16.7%、64.7%～65.2%和12.9%～13.4%,以南酸枣-杉木混交林中南酸枣木材导管组织比量和纤维组织比量最大,但差异均不显著;仅纯林的木材轴向薄壁组织比量(5.8%)显著高于混交林(5.1%和5.2%).随树龄的增加,3种林分中南酸枣木材微纤丝角均逐渐减小,南酸枣-马尾松混交林、南酸枣-杉木混交林和南酸枣纯林中南酸枣木材微纤丝角分别为23.33°～16.82°、 23.20°～16.36°和23.34°～17.41°, 且仅在树龄16～25 a阶段,混交林中的南酸枣木材微纤丝角显著小于纯林, 其中又以南酸枣-杉木混交林中的南酸枣木材微纤丝角最小.研究结果显示,南酸枣-杉木混交林中南酸枣木材的解剖特性总体上最优,在南酸枣木材品质定向培育过程中宜选择杉木作为伴生树种.     

Genetic Variation in a4GnT in Relation to Helicobacter pylori Serology and Gastric Cancer Risk

Background:  Helicobacter pylori, a known risk factor of gastric cancer, rarely colonize the deeper portion of normal gastric glands, where the mucus is rich in α-1,4-linked N -acetylglucosamine capped O -glycans, that strongly inhibit H. pylori growth in vitro .
Materials and methods:  We investigated the association between genetic variation in the O -glycan transferase encoding gene ( a4GnT ) and H. pylori infection and gastric cancer risk using a Polish population-based case–control study (273 gastric cancer patients and 377 controls).
Results:  A haplotype at the rs2622694–rs397266 locus was associated with H. pylori infection, with the A-A haplotype associated with a higher risk compared with the most frequent G-G haplotype (odds ratio 2.30; 95% confidence interval 1.35–3.92). The association remained significant after correction for multiple tests (global p value: nominal 0.002, empirical 0.045). Neither this haplotype nor the tagSNPs were associated with overall gastric cancer risk.
Conclusion:  a4GnT genetic variation may be relevant to H. pylori infection, but not to gastric cancer risk.     

Toll-Like Receptor 4 +3725 G/C Polymorphism, Helicobacter pylori Seropositivity, and the Risk of Gastric Atrophy and Gastric Cancer in Japanese

Background:  Toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile polymorphisms were reported to be a risk factor of gastric carcinoma or its precursors in Caucasian and Indian population, but these polymorphisms are absent in Japanese. We investigated the associations of TLR4 +3725 G/C polymorphism, another functional polymorphism of TLR4 , with risk of gastric cancer and gastric atrophy in Japanese.
Materials and Methods:  Study subjects were 583 histologically diagnosed gastric cancer patients and age- and sex-matched 1592 control outpatients, who visited Aichi Cancer Center Hospital from 2001 to 2005. Serum anti- H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and gastric atrophy, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.
Results:  Among the seropositive subjects, the age- and sex-adjusted OR of gastric atrophy was 1.17 (95%CI: 0.91–1.50) for G/C , 1.20 (95%CI: 0.76–1.89) for C/C , and 1.18 (95%CI: 0.93–1.49) for G/C + C/C relative to G/G genotype. The age- and sex-adjusted OR of severe gastric atrophy among H. pylori seropositive subjects was 1.43 (95%CI: 0.99–2.06) for G/C , 1.47 (95%CI: 0.76–2.88) for C/C , and 1.43 (95%CI: 1.01–2.04) for G/C + C/C . The OR of gastric cancer compared with gastric atrophy controls was not statistically significant.
Conclusion:  Our study found that TLR4 +3725 G/C polymorphism was a risk factor of severe gastric atrophy in H. pylori seropositive Japanese. Our results underscored the significance of the variations in host innate immunity due to TLR4 polymorphism as genetic predispositions to gastric precancerous lesions in Eastern Asian populations with the same backgrounds.     

Antibacterial activity of fresh and processed red muscadine juice and the role of their polar compounds on Escherichia coli O157:H7

Aims:  The objectives of this research were to show the anti- Escherichia coli O157:H7 effect of fresh (FRMJ) and processed red muscadine (V itis rotundifolia ) juice (PRMJ) and to discern the active compounds responsible for anti- E . coli O157:H7.
Methods and Results:  Polar and phenolic compounds of FRMJ and PRMJ were analysed by high-performance liquid chromatography. Antibacterial activity of FRMJ, PRMJ, their polar and polyphenol fractions, individual synthetic acids and their mixture with or without sugars were investigated on E . coli O157:H7. FRMJ and PRMJ inactivated ( P  ≤ 0·05) 5-log cocktail cells of E. coli O157:H7 within 4 h at 37°C. Polar fractions that contained malic, tartaric and tannic acids showed strong antimicrobial activity ( P  ≤ 0·05) against E . coli O157:H7. Tannic acid among the synthetic acids showed the highest antimicrobial activity against E. coli O157:H7.
Conclusions:  FRMJ, PRMJ and their polar compounds showed strong anti- E . coli O157:H7 activity.
Significance and Impact of the Study:  Earlier findings have failed to show any anti -E . coli O157:H7 effect of grape juice without adding preservatives. Our findings show that red muscadine juice has natural antibacterial substances and suggest that these can be used as active antimicrobial ingredients against E . coli O157:H7 in nonalcoholic beverages.