Effects of habitat disturbance on mixed species bird flocks in a tropical sub-montane rainforest

Despite their vulnerability to forest disturbances in the Neotropics, the consequences of forest perturbation on mixed species flocks are poorly understood in the threatened Southeast Asian rainforests. We examined the effects of local-scale habitat disturbance on mixed species flocks along an escalating gradient of anthropogenic modification (i.e., forest interior, forest edge, and urban) in a sub-montane tropical rainforest in Peninsular Malaysia that is presently experiencing low intensity development. Mixed species flocks in the forest interior and forest edge habitats (9.3 ± 2.3 and 8.4 ± 2.3, respectively) had significantly higher number of species than those observed in the urban habitat (5.1 ± 1.7). Flock participation was influenced by environmental characteristics (e.g., canopy cover). Flocking species sensitive to habitat disturbance were likely to be from the Families Corvidae, Nectariniidae, and Sylviidae; had narrow to restricted altitudinal ranges; and were exclusively dependent on primary forest and understory microhabitats. We conclude that sub-montane mixed species flocks are affected by even small scale urbanization and that they, particularly with species richness as a parameter, can be used as effective ecological indicators. With the looming development pressure on the sub-montane/montane habitats in Peninsular Malaysia and the Southeast Asian region, urgent conservation actions are needed for the preservation of their biotas.     

Nulliparous versus primiparous crossbred females for beef

Feedlot and carcass traits of nulliparous and primiparous females representing eight breed types, including Bos taurus and Bos indicus x Bos taurus crosses, were evaluated. Nulliparous females (heifers) were in the feedlot for 4 mo; primiparous females (heiferettes) were fed for 2 1/3 mo after their calves were weaned at 6 mo of age. Heifers averaged higher (P less than .01) in dressing percentage, percentage of kidney fat, carcass grade (P less than .10), and color of lean (P less than .05) compared with heiferettes. Heiferettes exceeded the nulliparous group in feedlot ADG (P less than .01), fat thickness (P less than .05), and percentage of steak, roast, and bone (P less than .01). Parity effects on carcass weight, longissimus area, marbling, pH, and shear force value were not statistically significant. Dam breed types differed in several traits, including marbling (P less than .05) and percentage of steak (P less than .10), roast (P less than .01), and bone (P less than .01). Dam breed x parity interactions were nonsignificant. Results show that beef derived from heiferettes is competitive with heifer beef.     

Life-cycle evaluation of Bos taurus and Bos indicus X Bos taurus breed types in a dry, temperate climate: performance of mature dams

Mature dams representing Hereford, Red Poll, F1 Hereford x Red Poll, F1 Red Poll x Hereford, F1 Angus x Hereford, F1 Angus x Charolais, F1 Brahman x Hereford and F1 Brahman x Angus breed types were evaluated. All cows were bred to Limousin sires to produce two-way or three-way-cross progeny. Mature Brahman x Hereford dams produced a higher (P less than .05) percentage of live calves than Herefords, but dam breed differences in percentage of calves weaned relative to the number of cows exposed for mating were not statistically significant. Progeny of Angus x Charolais and Red Poll dams were outstanding in weaning weight, but Hereford and Brahman-cross calves were below average. Planned comparisons showed that Angus x Charolais calves were heavier (P less than .01) at weaning than Hereford (23.0 +/- 3.8 kg) or Angus x Hereford (9.6 +/- 3.2 kg) progeny. Mature Angus x Hereford mothers weaned heavier calves than did Brahman x Herefords (7.4 +/- 3.2 kg, P less than .05) or Brahman x Angus (10.9 +/- 3.0 kg, P less than .01). Analysis of the Hereford-Red Poll diallel showed evidence of maternal heterosis in calf weaning weight (4.0 +/- 2.6 kg, P less than .05), but there was no difference in the percentage of calves weaned by crossbred vs straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)     

汽蒸处理对落叶松木材物理性质的影响

本文取兴安落叶松(Larix gmelinii Rupr)生材加工成规格为20mm×20mm×20mm的试样;于常压下汽蒸1、2、4、8、16、32、48、64、96h。测定了气干和全干状态的干缩率、气干密度、基本密度和平衡含水率(EMC)等物理性质的变化情况。结果表明:①木材全干干缩率除汽蒸初始1h略有下降外,均随汽蒸的延续而逐渐增加,至64 h达最大值,径向、弦向和体积干缩率分别为7.28％、13.40％和21.85％,若继续延长汽蒸时间,干缩率稍有降低。②汽蒸过程中差异干缩值的变化不大,稍有降低。因而,汽蒸不会加剧差异干缩,并能使其有所改善。③气干密度和基本密度均随汽蒸的延续而逐渐降低,至48h降达最低值,分别为0.615g/cm~3和0.487g/cm~3,若继续汽蒸,气干密度和基本密度均稍有回升。④平衡含水率(EMC)随汽蒸的延续而逐渐降低,汽蒸96h降为8.53％。因此,汽蒸处理对落叶松木材物理性质的影响不大,落叶松成材汽蒸处理时间,一般不宜超过16h。     

水稻耐冷性对稻米品质冷水反应的影响

 利用从密阳 2 3/通 88 7和密阳 2 3/TR2 2 183杂交组合F3 代选拔获得的水稻耐冷性强的系统群和弱的系统群以及 3个亲本品种 ,探讨了冷水胁迫对稻米品质特性的影响以及水稻耐冷性对稻米品质冷水反应的影响。研究结果表明 ,冷水胁迫使水稻糙米粒形变小 ,其中糙米粒长度、长宽比和千粒重比宽度和厚度更容易受到冷水胁迫的负面影响。冷水胁迫使稻米碱消值和蛋白质含量增加 ,而使稻米胶稠度、直链淀粉含量、最高粘度、冷胶粘度和崩解值下降。在水稻幼苗期对耐冷性进行选择 ,对糙米粒形并不产生显著影响。在自然条件下耐冷性强的和弱的2个系统群间品质特性未见显著差异 ,但在冷水胁迫下幼苗期耐冷性强或田间耐冷性强的系统群直链淀粉含量、最高粘度、热浆粘度、冷胶粘度显著高于幼苗期耐冷性弱或田间耐冷性弱的系统群 ,而蛋白质含量、消减值、崩解值和消减率则相反。认为耐冷性强的系统群的稻米品质比耐冷性弱的系统群表现出较迟钝的冷水反应 ,耐冷性对稻米品质的冷水反应产生一定影响。因此 ,提高水稻耐冷性对水稻品质的稳定和改善将产生积极的影响。     

Zinc selectively blocks the action of N-methyl-D-aspartate on cortical neurons

Large amounts of zinc are present in synaptic vesicles of mammalian central excitatory boutons and may be released during synaptic activity, but the functional significance of the metal for excitatory neurotransmission is currently unknown. Zinc (10 to 1000 micromolar) was found to have little intrinsic membrane effect on cortical neurons, but invariably produced a zinc concentration-dependent, rapid-onset, reversible, and selective attenuation of the membrane responses to N-methyl-D-aspartate, homocysteate, or quinolinate. In contrast, zinc generally potentiated the membrane responses to quisqualate or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and often did not affect the response to kainate. Zinc also attenuated N-methyl-D-aspartate receptor-mediated neurotoxicity but not quisqualate or kainate neurotoxicity. The ability of zinc to specifically modulate postsynaptic neuronal responses to excitatory amino acid transmitters, reducing N-methyl-to-aspartate receptor-mediated excitation while often increasing quisqualate receptor-mediated excitation, is proposed to underlie its normal function at central excitatory synapses and furthermore could be relevant to neuronal cell loss in certain disease states.     

Influences of dietary uptake and reactive sulfides on metal bioavailability from aquatic sediments

Understanding how animals are exposed to the large repository of metal pollutants in aquatic sediments is complicated and is important in regulatory decisions. Experiments with four types of invertebrates showed that feeding behavior and dietary uptake control bioaccumulation of cadmium, silver, nickel, and zinc. Metal concentrations in animal tissue correlated with metal concentrations extracted from sediments, but not with metal in porewater, across a range of reactive sulfide concentrations, from 0.5 to 30 micromoles per gram. These results contradict the notion that metal bioavailability in sediments is controlled by geochemical equilibration of metals between porewater and reactive sulfides, a proposed basis for regulatory criteria for metals.     

The Anticancer Effect of Fucoidan in PC-3 Prostate Cancer Cells

Fucoidan, a sulfated polysaccharide, has a variety of biological activities, such as anti-cancer, anti-angiogenic and anti-inflammatory. However, the mechanisms of action of fucoidan as an anti-cancer agent have not been fully elucidated. The present study examined the anti-cancer effect of fucoidan obtained from Undaria pinnatifida in PC-3 cells, human prostate cancer cells. Fucoidan induced the apoptosis of PC-3 cells by activating both intrinsic and extrinsic pathways. The induction of apoptosis was accompanied by the activation of extracellular signal-regulated kinase mitogen-activated protein kinase (ERK1/2 MAPK) and the inactivation of p38 MAPK and phosphatidylinositol 3-kinase (PI3K)/Akt. In addition, fucoidan also induced the up-regulation of p21^Cip1/Waf and down-regulation of E2F-1 cell-cycle-related proteins. Furthermore, in the Wnt/β-catenin pathway, fucoidan activated GSK-3β that resulted in the decrease of β-catenin level, followed by the decrease of c-myc and cyclin D1 expressions, target genes of β-catenin in PC-3 cells. These results suggested that fucoidan treatment could induce intrinsic and extrinsic apoptosis pathways via the activation of ERK1/2 MAPK, the inactivation of p38 MAPK and PI3K/Akt signaling pathway, and the down-regulation of Wnt/β-catenin signaling pathway in PC-3 prostate cancer cells. These data support that fucoidan might have potential for the treatment of prostate cancer.     

Proposal of screening method for intestinal mucus adhesive lactobacilli using the enzymatic activity of glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH)

Adhesion tests are complex, time‐consuming and expensive, while the most important criterion for a probiotic lactobacilli is the ability to adhere to the human intestine. Thirty lactobacilli isolates from human intestinal tissues were measured for cell surface glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) activity using a microtiter plate screening method. GAPDH activities were detected in 21 out of 30 samples from 12 h cultures and in all samples from 18 h cultures. This suggests GAPDH is universally expressed on the bacterial cell surfaces from many lactobacilli. A statistically significant positive correlation was shown between GAPDH activity and adhesion using the BIACORE adhesion assay (P < 0.01). The new screening method using GAPDH enzymatic activity without an adhesion test may be possible due to the significant positive correlation of GAPDH activity with adhesion of lactobacilli derived from the human intestine.     

Effect of combined water and salinity stress factors on evapotranspiration of Sedum kamtschaticum Fischer in relation to green roof irrigation

In dryland areas, secondarily treated municipal wastewater could be used in extensive green roof systems. In this study, the effects of water and salt stress on a crassulacean acid metabolism (CAM) plant, Sedum kamtschaticum Fischer, was evaluated under intermittent saline irrigation. The salinity of irrigation water varied from 6.0 to 18.0 dS m^?1. A reduction in soil water content and an increase in soil water electrical conductivity (EC) were observed during the irrigation interval (5–17 d) as a result of evapotranspiration (ET). The effect of soil water potential (SWP) on reduction of the ET ratio (ET_r) was successfully described with an equation that could be applicable to a wide range of soil salinities and water contents, to estimate ET. In this study, the stress factor was defined as the integration of solute potential, and matric potential less soil water content for optimum growth (less than ?0.1 MPa) with elapsed time. The stress factor rapidly reduced total ET in CAM plants but effectively increased water-use efficiency (WUE). Thus, by using CAM plants for green roofs under intermittent saline irrigation, the need for irrigation water is reduced without a considerable loss of plant biomass.