ACCUMULATION OF 4-O-β-D-GLUCOSIDE OF PROTOCATECHUIC ACID IN THE LEFT COLLETERIAL GLAND OF THE COCKROACH,PERIPLANETA AMERICANA.* I. PROPERTIES OF GLUCOSIDE SYNTHETASE.

As a preliminary to the study of the mode of action of juvenile hormone using the left colleterial gland of the cockroach, properties of the glucoside synthetase of protocatechuic acid were studied. For this purpose, a convenient assay method of phenolic glucoside synthetase (UDPG-phenol glucosyl transferase) was devised. The method is based on the determination of labeled protocatechuic acid glucoside which is synthesized from uridine diphosphate ¹⁴C-glucose and protocatechuic acid. The optimal pH for the glucoside synthetase reaction is 6.5. The enzyme activity is localized in a particulate fraction of fat body tissues and is partly found in the soluble fraction, presumably liberated during the course of centrifugation. In the female cockroach, the enzyme activity is distributed mainly in the fat body. Chemical analyses revealed that the reaction product is 4-O-β-D-glucoside of protocatechuic acid. The homogenate of fat body tissues can synthesize glucosides from UDPG and various phenols, such as O-aminophenol, p-nitrophenol and hydroquinone, as well as natural O-diphenols.     

蜚蠊棘-钟形感器冲动发放的适应

本实验研究蜚蠊后胸足胫节棘-钾形感器冲动发放的适应特性,用探针向棘窝方向推棘以兴奋感觉神经元,用胞外电极记录神经冲动的发放,显示明显的适应现象.用计算机对冲动信号进行分析作图可得时间-瞬时频率曲线,该曲线呈负幂函数分布并可用y=B(?)公式描述,其中k为回归系数,表示该感器的适应速率,棘移动距离可影响k值,棘移动距离越长,k值越大,表示适应速率减慢.高频率移动棘可使反应发生动态和稳态两方面的变化;前者显示后续反应的脉冲个数的减少,后者则显示k值的降低,意味着适应的加快.     

美洲蜚蠊机械感受器输出信号的计算机分析

对蜚蠊单个机械感受器诱发反应峰电位的历程及幅度,使用系列分析、栅分析、时序分布、累加密度函数、栅—频分析、特征参数的伪三维隐线显示、峰电位幅度概率密度函数、峰电位间隔概率密度函数等分析方法,获得较多的神经信号间隔编码信息,以揭示刺激和反应之间的复杂关系。峰电位间隔和栅—频分析图由函数经曲线拟合后,分别求得描述其动态过程的时间常数τ_1,τ_2和τ_3,应用上述多种分析显示方法,使研究者更为直观地观察和定量描述刺激—反应间的动态关系。     

蜚蠊单个棘—钟形感器冲动发放的特性

本文分析了蜚镰后胸足单个棘一钟形感器对机械位移刺激的反应模式以及冲动发放的特性.结果证明该感器是一种适应较慢的相位性触觉感受器,对触刺激有相当稳定的反应.     

THE STRUCTURE OF INTERSEGMENTAL MUSCLE FIBERS IN AN INSECT, PERIPLANETA AMERICANA L

The organization of intersegmental muscle fibers associated with the dorsal abdominal sclerites of the cockroach is described. These fibers correspond closely, in the disposition and derivation of the membranes of the transverse tubular system and sarcoplasmic reticulum cisternae, with insect synchronous flight muscle fibers, but differ markedly from these in their fibrillar architecture and mitochondrial content. The mitochondria are small and generally aligned alongside the prominent I bands of the sarcomere, and, in the best-oriented profiles of the A bands, thick filaments are associated with orbitals of twelve thin filaments, a configuration that has also been observed in striated fibers of insect visceral muscle. These structural features of insect muscles are compared and discussed in terms of possible variations in the control of contraction and relaxation, and in the nature of their mechanical role.     

呲虫啉、杀虫双对美洲蜚蠊中枢神经的电生理影响

本文运用美洲蜚蠊(Periplaneta americana)第V1腹神经节突触后电位细胞外记录方法研究了吡虫啉、杀虫双对中枢神经活动的影响。结果显示：1.73x10^-7mol/L吡虫啉和 1.38XlO^-5Stool/L杀虫双处理后初期均能引起自发性突触后电位发放增强,随后导致突触传递阻断。而吡虫啉较杀虫双阻断传递快,且用Ringer生理溶液冲洗不易恢复,表明吡虫啉较杀虫双激动剂活性更强。以3.37×10^-5mol/L甲胺磷预处理中枢神经样品后,再进行杀虫双处理,则突触后电位的发放频率和幅值有明显增强,产生连续超幅排放(overshooting)现象,相反,甲胺磷预处理对随后进行吡虫啉处理无明显影响。这些结果说明,吡虫啉、杀虫双和乙酰胆碱受体发生相互作用过程存在差异。     

REGULATION OF PROTEIN SYNTHESIS IN THE VENOM GLAND OF VIPERID SNAKES

Morphological changes in the venom gland of V. ammodytes were studied after the removal of the venom from the gland lumina (milking) It was found that the height of the secretory cells was changed during the secretory cycle. The patterns of the rough endoplasmic reticulum and of the Golgi complex were changed as well Milking induced an increased incorporation of [¹⁴C]amino acids into total and venom proteins In V ammodytes, during the first day after milking, 25% of the total counts in protein were precipitable by anti-venom serum, while at 8 days, 80% of the proteins synthesized were venom proteins At this stage, the incorporation was 10- and 20-fold that of unmilked glands for total and venom proteins, respectively. Venom was accumulated (secreted) in the gland lumina of V. ammodytes at a relatively high rate up to 2 wk after milking and leveled off afterwards. Intact glands and gland slices of V ammodytes and V palaestinae, taken from snakes a few days after milking, incorporated [¹⁴C]amino acids into proteins in vitro at a rate higher than that of unmilked glands. The activity of two exportable enzymes (phosphodiesterase and benzoyl arginyl ethyl esterase) was assayed in gland homogenates of V. ammodytes. It was found that 2–3 wk after milking, the intracellular level of these enzymes was up to 2-fold that of unmilked glands.     

THE ACCUMULATION OF ELECTROLYTES : II. SUGGESTIONS AS TO THE NATURE OF ACCUMULATION IN VALONIA

It is suggested that K enters chiefly as KOH, whose thermodynamic potential (proportional to the ionic activity product (a _K) (a _OH)) is greater outside than within. As this difference is maintained by the production of acid in the cell K continues to enter, and reaches a greater concentration inside than outside. KOH combines with a weak organic acid which is exchanged for HCl entering from the sea water (or its anion is exchanged for Cl^-), so that KCl accumulates in the sap. Na enters more slowly and its internal concentration remains below that of K. The facts indicate that penetration is chiefly in molecular form. As the system is not in equilibrium the suggestion is not susceptible of thermodynamic proof but it is useful in predicting the behavior of K, Na, and NH₄.     

HORMONAL REGULATION OF MORPHOGENESIS IN STREPTOCARPUS AND ITS RELEVANCE TO EVOLUTIONARY HISTORY OF THE GESNERIACEAE

Two morphogenetic patterns have contributed to phylogenetic diversification within the Gesneriaceae: accrescence of one of the paired cotyledons (anisocotyly), which serves to differentiate the subfamily Cyrtandroideae; sustained growth of the accrescent cotyledon accompanied by prolonged suppression and displacement of the embryonic apical meristem, which gives rise to an acaulescent, dorsiventral vegetative plant body (phyllomorph) and further serves to differentiate species of Cyrtandroideae found in two tribes and several genera including Streptocarpus. It was possible to prevent cotyledonary accrescence and induce caulescence at will, either by supplying exogenous GA₃ or inhibiting auxin transport in species of Streptocarpus that normally manifest an extreme, phyllomorphic morphology. It was also possible to induce sustained, phyllomorphic development of cotyledons that are normally non-accrescent with exogenous cytokinin. Therefore morphogenetic capacities previously thought to be “lost” or “lacking” in subgenus Streptocarpus and, with respect to isocotyly, the tribe Cyrtandroideae, are, in fact, present but suppressed. An hypothesis regarding the role of hormones with respect to morphogenesis and phylogeny of Streptocarpus is suggested.     

CADMIUM AND MANGANESE ACCUMULATION IN PHYTOLACCA AMERICANA L. AND THE ROLES OF NON-PROTEIN THIOLS AND ORGANIC ACIDS

Phytolacca americana L. can accumulate large amounts of heavy metals in its aerial tissues, especially cadmium (Cd) and manganese (Mn). It has great potential for use in phytoextraction of metals from multi-metal-contaminated soils. This study was conducted to further investigate the Cd- and Mn-tolerance strategies of this plant. Concentrations of non-protein thiols (NPTs) and phytochelatins (PCs) in leaves and roots increased significantly as the concentration of Cd in solution increased. The molar ratios of PCs:soluble Cd ranged from 1.8 to 3.6 in roots and 8.1 to 31.6 in leaves, suggesting that the cellular response involving PC synthesis was sufficient to complex Cd ions in the cytosol, especially that of leaves. In contrast, excess Mn treatments did not result in a significant increase in NPT or PC concentrations in leaves or roots. Oxalic acid concentrations in leaves of plants exposed to 2 or 20 mM Mn reached 69.4 to 89.3 mg (0.771 to 0.992 mmol) g^–1 dry weight, respectively, which was approximately 3.7- to 8.6-fold higher than the Mn level in the 0.6 M HCl extract. Thus, oxalic acid may play an important role in the detoxification of Mn.     

MECHANISM OF ACTION OF β-N-OXALYL-L-α, β-DIAMINOPROPIONIC ACID, THE LATHYRUS SATIVUS NEUROTOXIN

The source of ammonia in the brain tissue of young rats treated with β-N-oxalyl-l -α, β-diaminopropionic acid (ODAP) has been studied. ODAP administration to 12-day-old rats causes a significant increase in the levels of adenylic acid deaminase in the brain. Glutaminase activity also shows an increase under these conditions. An increase in the levels of acid protease and transglutaminase is also observed in the brain of ODAP-treated animals. Glutamate dehydrogenase activity is decreased slightly. Glutamine synthetase enzyme is not affected. Aspartate-α-ketoglutarate transaminase and aspartate-pyruvate transaminase activities are enhanced in the brain tissue of ODAP-treated rats. It is held that protein degradation, especially the cleavage of free and protein-bound amide bonds, may be responsible for excess ammonia liberation in the brain of ODAP-treated young rats.     

REGULATION OF FATTY ACID COMPOSITION BY IRRADIANCE LEVEL IN THE EUSTIGMATOPHYTE NANNOCHLOROPSIS SP.1

Chemical composition and quantitative cytological measurements were determined for the eustigmatophyte Nannochloropsis sp. Cultures were grown in turbidostats at three irradiance levels: growth-limiting light, growth-saturating light and photoinhibiting light. Cellular chlorophyll a content decreased as irradiance level increased, concomitant with a disproportionate reduction in carotenoid content. Nannochloropsis sp. grown in saturating light was characterized by a high content of lipid, fatty acids and carbohydrate compared with cells grown in light-limiting conditions. The increase in cellular lipid content coincided with a reduction in the percentage of eicosapentaenoic acid (C20:5) and arachidonic acid (C20:4), fatty acids that are mainly associated with galactolipids, and with an increase in the relative abundance of palmitic acid (C16:0) and palmitoleic acid (C16:1). At growth limiting light conditions, Nannochloropsis sp. preferentially synthesized galactolipids; however, as growth became light saturated, relatively more neutral lipids, mainly triacylglycerols, were synthesized. Changes in lipid content and composition were qualitatively related to changes in cell morphology. Cells grown under low light conditions were characterized by a large relative volume of chloroplast, high surface density of thylakoid membranes and low relative volume of lipid storage bodies. The physiological implications of the changes in cellular lipid composition and ultrastructure are discussed in relation to light/shade adaptation.     

DIATOM MINERALIZATION OF SILICIC ACID. II. REGULATION OF Si (OH)4 TRANSPORT RATES DURING THE CELL CYCLE OF NAVICULA PELLICULOSA1

Synchronized populations of Navicula pelliculosa (Bréb.) Hilse show a 10-fold increase in Si(OH)₄ transport rate during traverse through the cell division cycle. The transport activity pattern is similar to a “peak enzyme.” Kinetic analysis showed there was a significant change in K_s values, indicating increased “affinity” for Si(OH)₄ as cells neared maximal uptake rates. However, the dramatic changes in transport rate at various cell cycle stages were also reflected by alterations in the V_max, values of the transport process, suggesting a change in the number of functional transport “sites” in the plasma membrane. Cells in the wall forming stage, arrested from further development by Si(OH)₄ deprivation, maintained high transport rates for as long as 7 h. The rates decreased rapidly if protein synthesis were blocked or if Si(OH)₄ was added, the latter allowing the cells to traverse the rest of the cycle. The half-life of the transport activity ranged from 1.0 to 2.2 h when protein synthesis was inhibited at various cell cycle stages and during the natural decline of activity late in the cycle. The transport system appears to be metabolically unstable as is typical for a “peak protein.” The rise in transport rate through the cell cycle did not depend on the presence of Si(OH)₄ in the medium; therefore, the transport system does not appear to be induced by its substrate. The rise in transport is also observed in L:D synchronized cells developing in the presence of Si(OH)₄; neither does the transport system appear to be derepressed. The transport rate was strongly cell cycle-stage dependent; the data appeared to fit the “dependent pathway” model proposed by Hart-well to explain oscillations in enzyme synthesis during the cell cycle.     

ROLE OF ADENOSINE 3'', 5''-MONOPHOSPHATE IN THE REGULATION OF CIRCADIAN OSCILLATION OF SEROTONIN N-ACETYLTRANSFERASE ACTIVITY IN CULTURED CHICKEN PINEAL GLAND

—When pineal glands of 10–12-day-old chicks were organ-cultured in darkness, serotonin N-acetyltransferase activity was low during the daytime, increased at midnight and then decreased to the daytime level the next morning. The pattern of increase and decrease of enzyme activity in cultured pineal glands was comparable to the circadian rhythm of N-acetyltransferase activity in vivo. When pineal glands were kept at a low temperature for 5 h prior to culture, the phase of autonomous rhythm of enzyme activity was delayed. When chicken pineal glands were cultured during the daytime for 6 h, derivatives of adenosine 3′, 5′-monophosphate (cyclic AMP), cholera toxin, a high concentration of KCl and phosphodiesterase inhibitors increased N-acetyltransferase activity 3–7-fold, indicating an involvement of cyclic AMP in the regulation of N-acetyltransferase activity in chicken pineal gland as has been shown in rat pineal gland. When pineal glands were cultured at night in darkness, cholera toxin or a high KCl did not enhance the night-time increase of the enzyme activity. Derivatives of cyclic AMP or phosphodiesterase inhibitors enhanced the autonomous night-time increase of N-acetyltransferase activity in an additive or more than additive manner in cultured pineal glands. These observations suggest that adenylate cyclase of pinealocytes is inactive during daytime, but is activated at night in darkness, which is transduced to the synthesis of N-acetyltransferase molecules. Catecholamines suppressed the basal level and the nocturnal increase of N-acetyltransferase activity via α-adrenergic receptor. The nocturnal increase of enzyme activity was prevented by cycloheximide or actinomycin D. Cocaine, which stabilizes cell membrane potential or light exposure, blocked the nighttime increase of N-acetyltransferase activity in cultured chicken pineal glands.     

BIOCHEMICAL CHARACTERIZATION OF β-N-OXALYL-l-α,β-DIAMINOPROPIONIC ACID, THE LATHYRUS SATIVUS NEUROTOXIN AS AN EXCITANT AMINO ACID

Abstract— β- N -Oxalyl- l -α,β-diaminopropionic acid (ODAP), the toxin isolated from the seeds of Luthyrus sativus produces head retraction, tremors and convulsions when injected into a variety of experimental animals. In 12-day-old rats, it has been found that the convulsive behaviour is accompanied by profound biochemical changes in the brain. The brain homogenates prepared from ODAP injected animals show a higher rate of respiration. There is a decrease in the brain glucose, glycogen, ATP, phosphocreatine and acetylcholine levels of the convulsing animals. The inorganic phosphate, lactic acid and acetylcholineesterase levels increase. These results establish that ODAP is a typical convulsant.     

LOCALIZATION OF EXTRANEURONAL DOPAMINE-β-HYDROXYLASE IN RAT SALIVARY GLAND BY IMMUNOFLUORESCENCE HISTOCHEMISTRY

Abstract— Superior cervical ganglionectomy results in a complete noradrenergic neuronal denervation of the rat sublingual-submaxillary salivary gland. Dopamine-β-hydroxylase activity in the serous submaxillary gland falls approximately 90% after noradrenergic denervation; but in the mucinproducing sublingual gland dopamine-β-hydroxylase activity is reduced by only 33%. Dopamine-β-hydroxylase immunofluorescence in the submaxillary gland is distributed with noradrenergic neurons and is eliminated by superior cervical ganglionectomy. In the sublingual gland dopamine-β-hydroxylase immunofluorescence is localized within mucinous acini and small ducts, and the disposition and intensity of staining materials is not affected by noradrenergic denervation for up to 30 days. DBH protein in the sublingual gland had little physiologic activity in vivo. Low levels of authentic dopamine-β-hydroxylase activity were detected in saliva. Thus, dopamine-β-hydroxylase protein is present in the sublingual gland in an extraneuronal location and appears to be a secretory product of the gland.