Microbial community composition and enzyme activities in a sandy loam soil after fumigation with methyl bromide or alternative biocides

A sandy loam soil was fumigated in microcosms for 24 h with methyl bromide and chloropicrin (MeBr+CP), propargyl bromide (PrBr), combinations of 1,3-dichloropropene and CP (InLine), iodomethane and CP (Midas), an emulsifiable concentrate of CP (CP-EC), or methyl isothiocyanate (MITC). The effects of these pesticides on fatty acid methyl ester (FAME) profiles and selected enzymatic activities were evaluated in fumigated soils and a nonfumigated control at 1, 3, 7, 14, 21, 28, and 90 days post-fumigation. Bacterial (a15:0, i15:0, i16:0, cy17:0, a17:0 and i17:0) and fungal (18:2ω6, 18:3ω6, 18:1ω9) FAMEs were initially (1 day post-fumigation) reduced by fumigation with CP-EC, InLine, and Midas. Microbial communities of soils fumigated with MeBr+CP, MITC, and PrBr resembled those of the control soil. At 14-28 days post-fumigation, FAME profiles were changed in all fumigated soils relative to the control, with the exception of soils treated with MITC. At 90 days post-fumigation, FAME profiles suggested that actinomycetes (10 Me 16:0, 10 Me 17:0, 10 Me 18:0) and Gram-positive bacteria may recover preferentially after fumigation with most of the pesticides studied. Among the fumigants tested, InLine, Midas, and CP-EC had a higher potential to alter the microbial community structure in the longer term than MeBr+CP, PrBr and MITC, with MITC having the least effect. Soil enzyme activities in fumigated microcosms were significantly (P≤0.037) different from the nonfumigated soil, with the exception of β-glucosidase in soils treated with PrBr and MITC, and dehydrogenase in MeBr+CP-fumigated soils. Over the 90-day study, soil fumigation (average of all fumigants and sampling dates) reduced the activities of arylsulfatase (62%), dehydrogenase (35%), acid phosphatase (22%), and β-glucosidase (6%), suggesting that S mineralization in soils and the total oxidative potential of microorganisms were more affected by fumigation than P and C mineralization. This study also indicates that soil fumigation with MeBr+CP alternative biocides has the potential to alter microbial communities and important key reactions involved in nutrient transformation.     

Medium‐ and short‐term available organic matter,microbial biomass,and enzyme activities in soils under Pinus sylvestris L. and Robinia pseudoacacia L. in a sandy soil in NE Saxony,Germany

Total, mobile, and easily available C and N fractions, microbial biomass, and enzyme activities in a sandy soil under pine (Pinus sylvestris L.) and black locust (Robinia pseudoacacia L.) stands were investigated in a field study near Riesa, NE Germany. Samples of the organic layers (Oi and Oe‐Oa) and the mineral soil (0–5, 5–10, 10–20, and 10–30 cm) were taken in fall 1999 and analyzed for their contents of organic C and total N, hot‐water‐extractable organic C and N (HWC and HWN), KCl‐extractable organic C and N (C_org(KCl) and N_org(KCl)), NH ‐N and NO ‐N, microbial‐biomass C and N, and activities of β‐glucosidase and L‐asparaginase. With exception of the HWC, all investigated C and N pools showed a clear response to tilling, which was most pronounced in the Oi horizon. Compared to soils under pine, those under black locust had higher contents of medium‐ and short‐term available C (HWC, C_org(KCl)) and N (HWN, N_org(KCl)), mineral N (NH ‐N, NO ‐N), microbial‐biomass C and N, and enzyme activities in the uppermost horizons of the soil. The strong depth gradient found for all studied parameters was most pronounced in soils under black locust. Microbial‐biomass C and N and enzyme activities were closely related to the amounts of readily mineralizable organic C (HWC and C_org(KCl)). However, the presented results implicate a faster C and N turnover in the top‐soil layers under black locust caused by higher N‐input rates by symbiotic N₂ fixation.     

Assisted reproduction for felid species conservation—Sperm competences at risk

Cryobanking of gametes in combination with artificial insemination is an essential option to support conservation programmes for endangered and threatened species. About two-thirds of the felid species are classified as ‘near threatened’, ‘vulnerable’ or ‘endangered’ ( www.cites.org ), and mostly, epididymal sperm are collected from euthanized or castrated male felids and cryopreserved. However, epididymal compared with ejaculated and cryopreserved compared with fresh sperm have a limited potential to fertilize if vaginal non-surgical insemination is applied in feline species. Missing or highly diluted seminal fluid in epididymal and cryopreserved sperm, as well as a potential interference of extender ingredients with the natural interactive properties of sperm in the female genital tract is discussed as potential drawback which hampers a proper sperm transit and fertilization besides the limited longevity of cryopreserved feline sperm. Individual components in seminal fluid as well as cryoextenders may adversely alter sperm properties and have a different impact on fertility and preservation success. The identification and investigation of beneficial as well as detrimental components is a precondition to deduce options for improving the process of cryopreservation in felids, particularly, if only epididymal sperm are available.     

外源茉莉酸甲酯诱导茶树鲜叶及其采后乌龙茶加工关键工序中七种脂溶性色素变化

【目的】系统开展外源茉莉酸甲酯诱导以及“做青”阶段机械损伤双重胁迫下茶叶中脂溶性色素的动态变化研究,阐明外源茉莉酸甲酯诱导后茶树鲜叶制得乌龙茶中类胡萝卜素含量提高的机理,为合理利用外源诱导提升鲜叶品质和加工制得的乌龙茶品质提供科学依据。【方法】0.25%外源茉莉酸甲酯喷施3—4年生盆栽‘金萱’茶树叶面,至均匀挂滴,对不同诱导时间（0、12、24、48和168 h）的鲜叶及利用该鲜叶制作得到的乌龙茶样品进行基于UPLC-QToFMS的靶标代谢组学分析,解析叶黄素、β-胡萝卜素、新叶黄素、玉米黄质、α-胡萝卜素和叶绿素a/b的含量变化;同时对乌龙茶制作的关键工序“做青”以及杀青后揉捻阶段样品中这些脂溶性色素的动态变化进行监测分析。同时,开展不同诱导时间采摘的鲜叶加工得到成品乌龙茶的香气感官评价。【结果】靶标代谢组学分析结果表明,叶黄素是‘金萱’鲜叶中含量最高的类胡萝卜素,其含量达到（405.06±17.71）µg·g^-1,在成品乌龙茶中含量显著下降,仅为（277.36±32.72）µg·g^-1。外源茉莉酸甲酯诱导后,脂溶性色素含量变化显著,诱导48 h内,茶树鲜叶中叶绿素a含量较对照鲜叶中（0 h）增加,随后显著下降;叶绿素b在诱导后的鲜叶中始终处于减少的趋势。叶黄素在12 h样品中含量显著下降,在24 h的样品中其含量均较对照升高;β-胡萝卜素在诱导后的鲜叶中含量始终低于对照,其中12 h的样品中含量仅为116.36 µg·g^-1,减少34.55%。利用茉莉酸甲酯诱导后的鲜叶（12、24和48 h）制作得到的成品茶样品中叶绿素a含量较对照均显著下降;叶黄素含量显著升高,其中48 h的样品中含量最高,达到377.82 µg·g ^-1。“做青”过程中（W1—W3）,对7种脂溶性色素含量变化进行相应的热图分析,与对照相比,叶绿素a含量均显著下降,而叶绿素b含量则在12 h样品中显著升高。5种类胡萝卜素的含量动态变化则更加复杂,含量最高的叶黄素在12 h样品中含量显著下降,随后在24和48 h的样品中含量略有升高;β-胡萝卜素的含量始终低于对照。此外,玉米黄质和α-胡萝卜素在诱导12 h以后的样品中始终维持非常高的含量。揉捻阶段的样品,7种脂溶性色素也呈现出显著变化,除了β-胡萝卜素含量较对照样品减少,叶黄素、新叶黄素、玉米黄质以及α-胡萝卜素的含量在诱导12 h后的样品中均比对照高。茉莉酸甲酯诱导的样品中,叶绿素a的含量降低,叶绿素b的含量在诱导12 h后增加。此外,茶叶感官审评结果表明,外源茉莉酸甲酯诱导后茶树鲜叶加工得到的乌龙茶香气品质显著提升,具有持久浓郁的花香,然而其叶底明亮度和柔软性较未处理的对照样品有所下降。【结论】外源茉莉酸甲酯诱导茶树鲜叶,24 h内可以显著提高鲜叶及成品茶中的类胡萝卜素含量,诱导12 h后鲜叶加工得到的成品茶香气品质显著提高,具有浓郁的花香。外源诱导与“做青”机械损伤双重胁迫激发茶鲜叶中脂溶性色素的差异积累。     

Effects of substance P and distribution of substance P-like immunoreactivity in nerves supplying the stomach of the cod,Gadus morhua

The innervation of the cod stomach by neurons showing substance P-like immunoreactivity (SPLI), and the effect and mechanism of action of substance P (SP) on the vascularly perfused cod stomach and on isolated muscle strip preparations from the pyloric sphincter have been investigated. Infusion of SP produced a contraction of the stomach wall, which could not be blocked by tetrodotoxin, atropine or methysergide, indicating a direct effect on the stomach smooth muscle. Similarly, the contraction produced by SP on preparations from the pyloric sphincter was unaffected by tetrodotoxin. Nerves showing SPLI were frequent in the myenteric plexus of the whole stomach, and in the submucosa and mucosa of the pyloric part of the stomach. SPLI was also observed in fibres in the intestinal branch of the vagus and occasionally in the splanchnic nerves. Ligation of the nerves showed an accumulation of SPLI above as well as below the ligature, being more prominent proximal to the ligature in the vagus and distal to the ligature in the splanchnic nerve. In the vagus nerve, descending and ascending SPLI-fibres were seen surrounding non-reactive cell bodies. No reduction in intensity of the immunoreaction of the neurons in the stomach wall was observed after ligation or sectioning of the vagosympathetic trunk or the splanchnic nerves, nor were SP-levels measured by radioimmunoassay reduced. After denervation of vagal branches close to the stomach wall an insignificant decrease of immunoreactivity was observed in the myenteric plexus. Capsaicin treatment had no conclusive effect on the distribution of SPLI. It is concluded that the innervation showing SPLI may be of intrinsic as well as extrinsic origin, with pathways in both vagal and splanchnic branches. Only a direct effect of SP on the smooth muscle could be demonstrated.     

Control of gallbladder motility in the rainbow trout,Salmo gairdneri

Immunohistochemistry revealed nerves containing VIP-like and 5-HT-like material in both gallbladder wall and bile duct of the rainbow trout, while endocrine cells containing gastrin/CCK-like and substance P-like material were present in the mucosa of the bile duct and the duodenum. Fluorescence histochemistry showed adrenergic nerves close to the muscle layer of the gallbladder.Sulphated CCK8, caerulein and non-sulphated CCK8 (in this order of potency), 5-HT and acetylcholine were excitatory on isolated strip preparations, while VIP and adrenergic agonists were inhibitory. The adrenergic drugs were probably actingvia a beta-adrenergic receptor, while the effects of 5-HT and cholinergic drugs were antagonized by methysergide and atropine respectively.Electrical stimulation of the gallbladder nervesin situ failed to show any effect or under certain conditions induced a rebound effect.It is concluded that the motility control of the rainbow trout gallbladder may involve an inhibitory innervation by adrenergic and possibly VIP-releasing nerves, while 5-HT, acetylcholine and a CCK-like substance may be involved in the excitatory control.     

Autonomic innervation of the ovary of the Atlantic cod,Gadus morhua

The autonomic innervation of the ovary of the Atlantic cod was investigated using histochemical and physiological/pharmacological methods. The paired ovary receives autonomic innervation via branches of the posterior splanchnic nerve (vesicular nerve).Histochemical studies demonstrated vasoactive intestinal polypeptide (VIP)-immunoreactive, 5-hydroxytryptamine-immunoreactive and adrenergic nerve fibers, but a number of antisera raised against other peptides failed to reveal any specific reaction in the tissue preparations. It is concluded that the cod ovary receives a double antagonistic autonomic innervation of excitatory cholinergic fibers and non-adrenergic inhibitory fibers. The nature of the inhibitory neurotransmitter is not known.     

Flavonol-rich fractions of yaupon holly leaves (Ilex vomitoria, Aquifoliaceae) induce microRNA-146a and have anti-inflammatory and chemopreventive effects in intestinal myofibroblast CCD-18Co cells

Polyphenolics extracted from yaupon holly (Ilex vomitoria, Aquifoliaceae) (YH) leaves were investigated in human colon cells for their chemopreventive and anti-inflammatory activities. An activity-guided fractionation allowed the selection of YH flavonol-rich fraction due to its preferential inhibition of HT-29 colon cancer viability over the normal CCD-18Co colon cells. Quercetin and kaempferol 3-rutinosides, main components identified in this fraction, protected CCD-18Co cells against reactive oxidative species (ROS) in part due to increased activity of antioxidant enzymes. In addition, up-regulation of microRNA-146a (miR-146a) known as a negative regulator of pro-inflammatory NF-κB activation was the underlying molecular mechanism that protected CCD-18Co from inflammation.