Leaf litter and its nutrient contribution in the cacao agroforestry system

Cacao agroforestry systems (cacao-AFS) produce abundant litter. After decomposing, litter releases nutrients into the soil. The aim of this research was to estimate litter production and its nutrient content in 35- and 55-year-old cacao-AFS. The research was conducted in three cacao-AFS of each age, in Cardenas, Tabasco, México. Four traps per cacao-AFS were used to collect litter. Litter was collected every 15 days for one year. It was then fractioned into cacao leaves, shade tree leaves, petioles, branches and stems, and cacao flowers and fruits. To determine nutrient content of litter, samples were composited by age of cacao-AFS and by season of the year. Then chemical analysis was done in triplicate. Data were subjected to analysis of variance, orthogonal contrasts, and Student t and Duncan tests. Cacao-AFS produce litter all year. Thirty-five-year-old cacao-AFS produced more litter than 55-year-old cacao-AFS (2042 vs 1570 kg DM ha^?1 year^?1). Except for the shade tree leaf fraction (559.5 vs 642 kg DM ha^?1), 35-year-old cacao-AFS were superior to 55-year-old cacao-AFS in all the other litter fractions. Cacao leaf fraction was the main source of litter in cacao-AFS of both ages. Neither age of cacao-AFS nor the season of the year affected N, K, Zn or S content in litter. Orthogonal contrasts indicated statistical differences between ages of cacao-AFS for P, Ca, and Fe content in litter. Both N–P–K–Ca–Mg contents in litter of 35-year-old cacao-AFS (1.2–0.4–1.2–1.7–0.4%) and in litter of 55-year-old cacao-AFS (1.1–0.6–1.2–1.4–0.4%) are enough to recover the nutrients extracted by the cacao crop.     

高关水库鲢、鳙鱼的生长与合理利用的研究

对高关水库96尾鲢鱼[Hypophthalmichthys molitrix]和160尾鳙鱼[Aristichthysnobilis]作常规的生物学测定和统计运算后得出,鲢、鳙鱼体长与鳞长呈直线相关、体长与体重星幂函致相关。鲢、鳙鱼的生长规律符合Von.Bertalarffy生长方程。计算得鲢、鳙鱼的生长参数为:L_∞=80.884厘米、107.927厘米,W_∞=7332.75克、16334.598克,K=0.322、0.219,t_0=O.214年、0.308年,生长拐点年龄为3.627年、5.326年,拐点体重为2173.89克、4842.28克。高关水库以鲢鱼的拐点体重(2173.89克)作为捕捞规格、年捕捞强度为0.80、放养鱼种的规格在5寸以上,则鱼产量可望达到30万公斤。     

UV-C辐射玉米种子对叶片保护酶活性及叶表皮形态的影响

以嫩单18玉米种子为实验材料,研究了不同时间的UV-C辐射对玉米叶片中保护酶活性和叶表皮特征的影响。结果显示:SOD、POD和CAT的活性变化趋势相似,即随辐射时间增加活性降低,辐射4h或6h时降到最低,之后有所上升,但是都低于对照组。UV-C辐射能缩小气孔的长、保卫细胞宽、表皮长细胞的长度和长细胞宽度;而叶长、叶宽和根条数明显增加(p<0.05),表明玉米在受到UV-C辐射时可通过增加叶面积和根条数来缓解辐射带来的伤害。     

Upper alimentary tract papillomas in calves related to papillomavirus infection

This study reports 3 cases of spontaneous papillomavirus infection in 1-week-old calves. Thickening of the omasum and abomasum wall, with acute inflammation, necrosis, ulceration, and neoplastic changes were seen in 1 calf. In the other 2, small papillomas were observed in the omasal mucosa, exhibiting proliferation of the parakeratinized epithelium. Papillomavirus antigens were detected by immunohistochemistry and virus-like particles were seen through electron microscopy.     

Fire severity as a key factor in post-fire regeneration of Pinus pinaster (Ait.) in Central Portugal

Context

Mediterranean pine woodlands are strongly affected by wildfires; however, there are knowledge gaps in the role of fire severity on Pinus pinaster Ait. regeneration.

Objectives

The principal questions were: (a) does post-fire regeneration of Maritime Pine differ where canopies were consumed to a low vs. high degree and (b) which factors, besides fire severity, could explain these differences.

Methods

Pine recruitment was monitored from 2 to 36?months after a summer wildfire in 18 25?m² plots, equally divided over two fire severity classes based on crown consumption. Besides the degree of crown consumption, three quantitative fire severity indices as well as post-fire site conditions, seed input and understory vegetation recovery were measured.

Results

Pine seedling densities were consistently higher in the plots with low than high crown consumption but due to marked spatial variability, they were only significantly different at two out of the eight sampling occasions. This variability could be explained by a quantitative index based on the diameter of twigs, as well as by seed input and post-fire site conditions (ash and litter cover).

Conclusion

Fire severity was found to strongly affect the pine recruitment following wildfire, using both a qualitative visual severity index and a quantitative, more labour-intensive one.     

Lobomycosis in Atlantic bottlenose dolphins from the Indian River Lagoon, Florida

OBJECTIVE: To determine the prevalence of lobomycosis, a mycotic infection of dolphins and humans caused by a yeastlike organism (Lacazia loboi), among dolphins in the Indian River Lagoon in Florida. DESIGN: Cross-sectional study. ANIMALS: 146 Atlantic bottlenose dolphins. PROCEDURE: Comprehensive health assessments of bottlenose dolphins in the Indian River Lagoon of Florida (n = 75) and in estuarine waters near Charleston, SC (71), were conducted during 2003 and 2004. Bottlenose dolphins were captured, examined, and released. Skin lesions were photographed and then biopsied. Tissue sections were stained with H&E and Gomori methenamine silver stains for identification of L. loboi. RESULTS: 9 of 30 (30%) dolphins captured in the southern portion of the Indian River Lagoon had lobomycosis, whereas none of the 45 dolphins captured in the northern portion of the lagoon or of the 71 dolphins captured near Charleston, SC, did. Affected dolphins had low serum alkaline phosphatase activities and high acute-phase protein concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that lobomycosis may be occurring in epidemic proportions among dolphins in the Indian River Lagoon. Localization of the disease to the southern portion of the lagoon, an area characterized by freshwater intrusion and lower salinity, suggests that exposure to environmental stressors may be contributing to the high prevalence of the disease, but specific factors are unknown. Because only dolphins and humans are naturally susceptible to infection, dolphins may represent a sentinel species for an emerging infectious disease.     

Flavanol content and antioxidant activity in winery byproducts

Proanthocyanidins, particularly those coming from wine and grape products, have became of interest to nutritionists. Particular attention is currently being paid to the exploitation of this kind of grape byproducts for obtaining bio-active phenolic compounds with potential application as food antioxidants and preventive agents against cancer and other diseases. In this work, the flavanol composition of various winery byproducts submitted to different degrees of industrial exploitation has been studied and their antioxidant activity determined using two different methods (TBARS and TEAC) to evaluate their interest as suitable sources for the preparation of flavanol-rich antioxidant extracts. All the byproducts studied were still good flavanol sources no matter their exploitation degree. An important conclusion was that dried grape seeds, obtained as an end byproduct after the color extraction and alcohol distillation of the wine pomace, still kept important flavanol concentrations and significant antioxidant activity, even if they were submitted to high temperatures. These byproducts can be considered a cheap source for the extraction of antioxidant flavanols, which can be used as dietary supplements or in the production of phytochemicals.     

Treatment of metastatic melanoma B16F10 by the flavonoids tangeretin, rutin, and diosmin

Melanoma is one of the most frequently metastasizing malignant neoplasias. This study examines an experimental model of pulmonary metastasis and the B16F10 cell subline, highly metastatic in the lung. Antimetastatic effects of the flavonoids tangeretin, rutin, and diosmin were analyzed, and at the same time an analysis of the metastatic activity of ethanol was performed, considered to be necessary because it is used as a vehicle for administering the flavonoids. Lentini's model, which complements the macroscopic evaluation of nodule numbers by using a stereoscopic microscope and image analysis at the microscopic level, was used. The greatest reduction in the number of metastatic nodules (52%) was obtained with diosmin; similarly, the percentages of implantation, growth index, and invasion index (79.40, 67.44, and 45.23%, respectively), were all compared with those of the ethanol group, considered to be an effective control group. Rutin- and tangeretin-treated groups also showed reductions of the same index compared with the ethanol group. It would seem that structural factors would better explain these results and the antimetastatic activity of each flavonoid and the respective metabolites.     

Flavonoid distribution during the development of leaves, flowers, stems, and roots of Rosmarinus officinalis. postulation of a biosynthetic pathway

The distribution of seven flavonoids, eriocitrin, luteolin 3'-O-beta-d-glucuronide, hesperidin, diosmin, isoscutellarein 7-O-glucoside, hispidulin 7-O-glucoside, and genkwanin, has been studied in Rosmarinus officinalis leaves, flowers, stems, and roots during plant growth. The maximum level reached by luteolin 3'-O-beta-d-glucuronide in leaves during June-August suggests the existence of a delay between the activation of the enzymes involved in the flavanone and flavone biosynthesis. The presence of hesperidin and diosmin in the vascular system is significant, and hesperidin shows even higher levels than the phenolic diterpenes and rosmarinic acid. The distribution of flavonoids observed in R. officinalis suggests a functional and structural relationship between phytoregulators and flavonoids, where flavonoids would be "protectors" of the activity of phytoregulators. A hypothesis for the general pathway of biosynthesis of these compounds in plants of the family Labiatae is proposed.