牵拉猫左心房所致的肾效应

本实验在50只麻醉猫中研究了牵拉左心房(LAS)对尿量(UV)、尿钠(U_(Na)V)和尿钾(U_KV)排出量的影响。在迷走神经完整的动物,LAS 导致 UV,U_(Na)V 和 U_KV(P<0.001)明显增加。切断迷走神经后 LAS 仍能使 UV,U_(Na)V 有所增加(p<0.01),但增加量明显低于迷走神经完整的动物(P<0.005)。在迷走神经完整的猫滴注肝素(10U/min/mg)后,LAS 也能引起 UV,U_(Na)V 和 U_KV 的增加,但增值明显低于没有滴注肝素的猫。在迷走神经切除后滴入肝素,则 LAS 的肾效应消失(p>0.05)。切断左侧肾神经后,LAS 引起神经完整肾尿量和尿钠排出显著增加(P<0.001)。而去神经肾对 LAS 的效应虽减弱,但其增值仍有显著性。两侧肾效应的差异,在统计学上是显著的(P<0.05)。上述结果说明,LAS 在麻醉猫中能引起尿量,尿钠和尿钾明显增加,这些效应是神经反射和体液机制共同作用的结果。     

Restriction analysis and sequencing of the ITS regions and 5.8S gene of rDNA of Ganoderma isolates from infected oil palm and coconut stumps in Malaysia

Use of Crassulacean acid metabolism (CAM) plants in México and worldwide has a long history, but the morphological and photosynthetic aspects of these plants have only been considered recently. Emphasis in this article is on the daily net CO₂ uptake ability by three species of agaves and three species of cacti that are currently extensively cultivated in México for beverages, food, fodder, and forage ‐ Agave mapisaga, A. salmiana, A. tequilana, Opuntia ficus‐indica, O. robusta and Stenocereus queretaroensis. Data under controlled conditions are used to help interpret seasonal net CO₂ uptake patterns observed in the field. These CAM plants have instantaneous and total daily net CO₂ uptake values similar to those for highly productive C₃ and C₄ crops. The future increase in the cultivated area of CAM plants will have both agronomical and ecological ramifications because of the ability of these plants to endure prolonged drought and to sequester carbon during extended dry periods when few C₃ and C₄ crops and non‐CAM native plants can fix atmospheric CO₂.     

Changes in Activity of Choline Acetylase in Central Nervous System of Rat after Intraventricular Administration of Noradrenaline

APPLICATION of strychnine or d-tubocurarine to the exposed cerebral cortex leads after a few minutes to abnormality in somatosensory evoked potentials^1,2. This consists of a surface negative wave (peak latency, 21–23 ms) which attains an amplitude five to twenty times greater than that of the normal evoked potentials and probably reflects excessive depolarization of the apical dendrites of pyramidal neurones. We wish to report the blocking of this effect by prior application of eserine to the cortex.     

The Effect of Current Photosynthesis on the Origin of Translocates in Old Tomato Leaves

The rate of carbon transport from an old tomato leaf (54 days),grown at 80 W m^–2, was measured under light flux densitiesbetween 7 and 90 W m^–2. Under low light, the rate of carbontransport over a 6 h period was about 1 mg C dm^–2 h^–1,well in excess of the concurrent photosynthetic rate. The lossfrom these leaves of ¹⁴C-leaf assimilate which was fixed beforethe experimental period amounted to 62 per cent of the totalinitial uptake and was higher than that from leaves with higherconcurrent photosynthetic rates. The higher loss of ¹⁴C fromleaves with low photosynthetic rates was due to a greater contributionof ¹⁴C from the starch and residue fractions. The rate of transportappeared to be determined by the concentration of the labilesucrose, not the total sucrose concentration. In comparisonwith young fully-expanded tomato leaves (Ho, 1976) the sizeof the labile sucrose pool appeared to decrease with age. Thephotosynthesistranslocation coefficient was low (k₁k₂=0•21)for an old tomato leaf. Based on these results a scheme of carbonpartitioning in relation to translocation is proposed. Criteriafor assessing the efficiency of translocation in leaves arediscussed.     

粘虫Leucania separata Walker的发育和成活与环境湿度的关系——Ⅱ.前蛹和蛹

本项工作系研究粘虫水分生态问题的第二部分。本文报导了25℃及32℃中,环境湿度对粘虫化蛹以及蛹的成活、发育、失重、失水的影响,结果表明:随着相对湿度的提高,前蛹的正常化蛹率和蛹的成活率增加,而畸形蛹率和前蛹干死率则下降。蛹的失重百分率和失水百分率均与相对湿度呈负相关,其致死失重百分率为28-30%,致死失水百分率为24-27%。低湿导致蛹体死亡的原因是水分的过多丧失。在蛹的整个发育过程中,蛹体失重的变化趋势,在各种湿度中表现是一致的,即第一天的失重量最大,第四天最少,此后又略有上升。不同发育期的蛹对低湿的抵抗力不同,初蛹期抗低湿能力较弱。另一方面,在较高的温度中,低湿对蛹的影响表现得更为明显。     

内皮素对家兔窦房结起搏细胞电活动的影响

本文用细胞内微电极技术观察了ＥＴ－１对家兔窦房结起搏细胞电生理活动的影响。所得结果如下：（１）在以ＥＴ－１作表面灌流时,起搏细胞的４相自动去极化的速度（ＶＤＤ）显著减慢,且呈浓度依赖性,结果导致起搏细胞的自发放电频率（ＲＰＦ）降低。（２）由ＥＴ－１引起的ＶＤＤ和ＲＰＦ下降,可由事先投用ＥＴ＿Ａ＾受体选择性阻断剂ＢＱ－１２３（２０,１００μｇ／Ｌ）所阻断。这一结果有力提示,ＥＴ－１对起搏细胞的电生理效应是由ＥＴ＿Ａ受体亚型介导的。（３）事先投用Ｋ＿（ＡＴＰ）通道阻断剂格列苯脲（１０μｍｏｌ／Ｌ）,可完全消除ＥＴ－１对起搏细胞的负性频率作用。根据上述结果,似可认为,ＥＴ－１与ＥＴ＿Ａ受体的结合可激活Ｋ＿（ＡＴＰ）通道,致使Ｋ￣＋电流增加和起搏细胞的ＶＤＤ减慢。     

適应性百日咳菌种的獲得与应用

1．用多次傅代方法在六号培养基上,经20代傅代所獲得之CS20菌株,虽仍为一相百日咳桿菌,但未獲得在含腺培养基上生是稳定之適应性。 2．C及P5菌株在不適宜的情况下长期培养而獲得之Cv及P5v菌株,经多次全面检查仍为一相百日咳桿菌,合乎生物制品法规之要求。在血清学、毒力、毒性、免疫力等方面与原菌株C及P5均一致,但在含腖之四号培养基上生长稳定有顯著之適应性。 3．雨年来100批大量生产百日咳原液中充分澄明了Cv及P5v在四号培养基上之適应性,且在免疫力方面与原菌株所作原液无差别。因Cv及P5v生是稳定,故较原菌株C及P5所生产之原液之浓度提高200％以上。该適应性地方性菌株是理想而適合於生产百日咳菌苗用的菌种。     

Translocation of Calcium in Relation to Tomato Fruit Growth

Regulation of the uptake and distribution of calcium in thetomato plant was investigated in plants grown in recirculatingnutrient solutions at electrical conductivities of 2,7,12 and17 millisiemens (mS). Despite an increased calcium content inthe nutrient solution at high conductivity (7–17 mS),the accumulation of calcium by fruit was progressively reducedby increasing salinity, particularly in the distal half. Theincidence of blossom-end rot in fruit (BER) also increased withsalinity. The uptake of water and ⁴⁵Ca by plants was substantially reducedin the high salinity treatment (17 mS) and, to a lesser extent,by high relative humidity (90 per cent r.h. at 20 °C). Further,the translocation of ⁴⁵Ca from roots to shoots was reduced byhigh salinity, while the percentage distribution of ⁴⁵Ca tothe apex was reduced by high humidity. Only approx. 2 per centof the ⁴⁵Ca taken up by a plant was imported by the truss. The uptake of ⁴⁵Ca and its distribution among pedicel, calyxand berry by detached fruit in 24 h showed that fruit from highsalinity plants had a reduced uptake and a lower accumulationof ⁴⁵ Ca in the berry than in the calyx. In addition, plants grown at high conductivity had a lower rateof xylem sap exudation from decapitated plants. The fruit ofthese plants had a smaller xylem cross-sectional area in thefruit pedicel and a smaller calyx than those of the low conductivitytreatment. Calcium, translocation, tomato, fruit, blossom-end rot     

家兔Bezold—Jarisch反射时区域性交感神经传出放电的变化

在46只麻醉兔,记录了经冠脉内注射尼古丁诱发Bezold-Jarisch反射时不同区域交感神经传出放电的变化。肾神经、心脏神经、脾神经、星状神经节-颈神经交通支和颈前神经节的颈外动脉支五个部位的交感性传出放电,在冠脉内注射尼古丁后均减少,其中以肾神经、心脏神经和脾神经的减少更为显著。此结果表明,交感神经传出放电减少所致的总外周阻力降低,在Bezold-Jarisch反射诱发的低血压中起着重要作用。