Evaluation of nitrogen fixation by bacteria in association with roots of tropical grasses

[This corrects the article on p. 494 in vol. 44.][This corrects the article on p. 496 in vol. 44.][This corrects the article on p. 498 in vol. 44.][This corrects the article on p. 499 in vol. 44.][This corrects the article on p. 503 in vol. 44.][This corrects the article on p. 506 in vol. 44.][This corrects the article on p. 507 in vol. 44.][This corrects the article on p. 512 in vol. 44.][This corrects the article on p. 513 in vol. 44.][This corrects the article on p. 517 in vol. 44.].     

Asymmetry of the cerebral hemispheres in man: a bridge binding the 1st and the 2d temporal gyri, superior face of the 2d temporal gyrus, and fusiform gyrus]

The autors study 76 human brains, 36 of which are dissected. They observe a "T1 T2 bridge" over the first temporal and second temporal gyri more often on the left side than on the right. They find the maximal width of the superior face of the second temporal gyrus predominant on the right side in 70% of cases, on the left side in 15% and equivalent on both sides in 15%. The fusiform gyrus is found wider on the left side in 53% of cases, on the right in 22% and equivalent on both sides in 25%.     

化学杀虫剂对不同类型棉田害虫、天敌种群的影响

研究了化学杀虫剂对6种不同类型棉田的害虫、天敌种群数量及其相互作用的影响。结果表明,化学防治使棉花苗期棉蚜数量下降,但不能抑制中后期棉蚜数量;除豆间棉田外,其他类型棉田化防区棉红蜘蛛和棉铃虫数量低于未防区。化学防治使各类型棉田天敌数量减少,以单作棉田天敌数量减少最明显,间套作棉田天敌数量下降幅度较小;此外,棉田不同天敌种群所受的影响存在一定差异,化学防治对瓢虫、捕食蝽类的影响显著,数量下降剧烈,但蜘蛛类群下降幅度比前两者小。化学防治对棉田害虫与天敌的相互关系的影响随棉田类型或害虫、天敌种类的不同而有所差异。     

Reconstituted basement-membrane matrix modulates fibroblast activities in vitro

Cellular growth and collagen biosynthesis were compared in dermal calf fibroblasts cultured on plastic or on a reconstituted basement membrane gel, termed matrigel. This matrix, extracted from Engelbreth-Holm-Swarm tumors, consists mainly of laminin, entactin, type IV collagen, and heparan sulfate proteoglycan. The multiplication rate of fibroblasts grown on matrigel was stimulated compared to that of monolayered cells cultured on plastic, and these cells formed multilayers after 4 days. Protein and collagen biosynthesis was reduced in fibroblasts cultured on matrigel. A higher proportion of the newly synthesized collagen (40%) was incorporated to the extracellular matrix in cultures grown on matrigel than in those grown on plastic (14%). Type III collagen was the preferential collagen type deposited on matrigel, and the ratio of type III:type I collagens secreted in the medium was also slightly higher in cultures grown on matrigel. Partially processed collagen was more abundant in fibroblasts grown on matrigel than in cells cultured on plastic. Finally, cells grown on matrigel exhibited a higher catabolic activity than cells grown on plastic. In this experimental model, the reconstituted basement-membrane matrix seems to influence the activities of fibroblasts significantly.     

A comparison of features and the microbial constitution of the fresh feces of pigs fed diets supplemented with or without dietary microbes

The features and the constitution of the microbial population of fresh feces were compared between pigs fed a diet supplemented with dietary microbes and pigs given nonsupplemented diets. The former were reared on farm C and the latter on farms A and B. The concentrations of ammonia-N, indole, and skatole of fresh feces were not significantly different between pigs reared on farm C and those raised on farms A and B, but the concentrations of ammonia-N and the skatole of fresh feces were significantly different between pigs reared on farms A and B. The total VFA (volatile fatty acids) concentration of fresh feces in pigs on farm C was slightly lower than in those on farms A and B. Moreover, the molar proportion of the acetic acid in feces in pigs on farm C was lower; inversely, that of propionic and butyric acids was higher in comparison with those on farms A and B. No differences were evident in the total viable counts of feces among pigs reared on the three different farms. Clostridium perfringens was abundant in feces of pigs raised on farms A and B, but it was not detected in pigs reared on farm C. Megasphaerae, bifidobacteria, and clostridia except for C. perfringens were more abundant in the feces of pigs fed a diet supplemented with dietary microbes on farm C, compared with pigs given the nonsupplemented diets on farms A and B.     

Cyclooxygenase and lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst

We have measured by radioimmunoassay the concentration and production of 5(S)-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), a metabolite in the lipoxygenase pathway, and PGs in different uterine compartments, and blastocysts during the preimplantation period in the rabbit. The production is defined as the synthesis minus the metabolism for a defined period of time. The pattern of uterine PGF production on days 5-6.5 was quite similar for the whole uterus and the myometrium showing a peak production on Day 6. The concentration and production of PGF were always higher in the endometrium. While significant production of PGE was noticed in the whole uterus on days 5-6 and in the myometrium on Day 6, the endometrium showed some production on these days. On the contrary, absolutely no production of this PG was observed in the endometrium on Day 6.5. The concentration and production of 6-keto-PGF1 alpha were always lower in the endometrium than those observed in the myometrium or the whole uterus. While highest production of this PG was found to be on Day 6.5 in the whole uterus and on Day 5 in the endometrium, the production in the myometrium remained constant on all days examined. The production of 5-HETE in the endometrium was noticeable on Days 5-6.5, in the whole uterus on Days 5 and 6.5, and in the myometrium only on Day 6.5. However, the concentrations of 5-HETE showed a tendency to be higher at 2 h than at 0 h in these compartments on Days 5-6.5. Furthermore, a linear increase in 5-HETE levels both at 0 h and 2 h was observed in the endometrium on Days 5-6.5; no such difference in mean 5-HETE level was noted in the whole uterus or myometrium on any of these days. The production of 5-HETE in the blastocyst was noted only on Day 5. The results not only demonstrate the presence of both the cyclooxygenase and the lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst, their differential operation in various compartments of the uterus on various days of early pregnancy suggests an integrated role for these mediators in embryo-uterine interaction during implantation.     

中国海南省锈菌资料补编

补充记载了采自海南省的9种锈菌。甲竹Bambusa remotiflora上的华南柄锈菌Puccinia austrosinensis、大花紫薇Lagerstroemia speciosa上的紫薇夏孢锈菌Uredo lagerstroemiae和海南薯Ipomoea sumatrana上的宽乳单胞锈菌Uromyces latimammatus为新种;厚叶素馨Jasminum pentaneurum上的巴氏查科锈菌Chaconia butleri、猪肚木Canthium horridum上的鱼骨木驼孢锈菌Hemileia canthii、牛筋果Harrisonia perforata上的牛筋果无眠多胞锈菌Kuehneola harrisoniae、毛咀签Gouania javanica上的椴叶咀签柄锈菌Puccinia gouaniae-tiliaefoliae、蒲桃Syzygium jambos上的番石榴柄锈菌Puccinia psidii以及象草Pennisetum purpureum上的钝叶草柄锈菌Puccinia stenotaphri为中国新记录。引证的标本均保存于中国科学院菌物标本馆（HMAS）。     

Rapid and enhanced repolarization in sandwich-cultured hepatocytes on an oxygen-permeable membrane

In this study, we established rat primary hepatocyte sandwich cultures on oxygen-permeable membranes and investigated the change in their repolarization. Functional bile canaliculi in sandwich-cultured hepatocytes on oxygen-permeable polydimethylsiloxane (PDMS) membranes were re-established more quickly than those in a conventional sandwich culture on polystyrene (PS). This enhanced biliary excretory activity was also observed in hepatocytes on another oxygen-permeable membrane plate but not on a PDMS surface whose oxygen permeability is blocked. An apical efflux transporter protein, Mrp2, was more rapidly distributed in hepatocytes cultured on PDMS membranes than in hepatocytes cultured on conventional PS plates. Moreover, the area of distribution of the Mrp2 in polarized hepatocytes cultured on PDMS membranes was more widespread than that for the hepatocytes grown on sandwich-cultured PS plates. The observation of ultrastructure in transmission electron microscopy clearly confirmed the presence of bile canalicular lumens possessing microvilli and tight junctions. Additionally, we demonstrated that the 7-ethoxyresorufin-O-deethylation activity of hepatocytes on PDMS membranes was also improved as compared to those on a PS surface. Therefore, sandwich-cultured hepatocytes on oxygen-permeable substrates can provide a simple tool for predicting the hepatic metabolism and toxicity of xenobiotics in vivo with short span and low cost in the course of drug discovery and evaluation.     

Effect of host-plant manipulation by a gall-inducing insect on abundance of herbivores on chestnut trees

We investigated plant-mediated effects of the stem gall wasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), on other herbivores on the chestnut tree Castanea crenata. In the early season, leaves emerged earlier and in greater numbers on galled shoots than on ungalled shoots. On galled shoots the leaf to shoot biomass ratio was lower and the leaves were physically different. In May and June the concentration of nitrogen in leaves was higher on galled shoots than on ungalled shoots. In July, the water content of leaves was lower on galled shoots. In May and June, the number of aphids, Myzocallis kuricola Matsumura (Homoptera: Aphidoidea), on leaves was higher on galled shoots than on ungalled shoots, but the opposite was true at the end of July. Laboratory experiments showed that aphid fecundity and body weight decrease were higher in May and June when aphids fed on leaves on a galled shoot than when they fed on those on ungalled shoots. In contrast, aphid performance in July was greater on ungalled leaves than on galled leaves. Our findings suggest that gall initiation in a chestnut tree affected aphid performance by affecting host plant quality.     

Influence of the blood meal source on the biology of Meccus picturatus Usinger 1939 (Hemiptera: Reduviidae: Triatominae) under laboratory conditions

Aspects related to hatching, time-lapse between presenting the blood meal and beginning of feeding, feeding time, postfeed defecation delay,life time, mortality and fecundity for each stage of Meccus picturatus, life-cycle were evaluated and compared in two cohorts of M. picturatus fed on hens or rabbits. The hatching rate observed for each of the two studied groups of eggs was 78.1% (n = 2298) on the group fed on hens and 82.1% (n = 2704) on that fed on rabbits, and the average time of hatching was 20 days. Mean time-lapse for beginning feeding was under 3 min in nymphal stages and postfeed defecation delay was under 10 min in all stages, in both cohorts. Mean feeding time was significantly (P < 0.05) shorter in triatomines fed on hens than on rabbits. A similar number of nymphs of each cohort, 69 fed on hens (34.5%) and 68 fed on rabbits (34%), completed the cycle. No significantly (P > 0.05) differences were recorded among the average times from NI to adult in the cohort fed on hens (196.8 15.8 days) and the average time in the cohort fed on rabbits (189.5 22.9). The average span in days for each stage fed on hens was not significantly different to the average span for each stage fed on rabbits. The number of blood meals at each nymphal stage varied from 1 to 6 in both cohorts. The mortality rates were higher on fifth nymphal stage, in both cohorts. No significant (P > 0.05) differences were recorded on mortality rates on most nymphal stages of both cohorts. The average number of eggs laid per female from the cohort fed on hens in a 9-month period was 791.1, whereas the average number of eggs in the cohort fed on rabbits was 928.3.     

Host influence on the frequency of block formation in males and females of Citellophilus tesquorum altaicus Ioff, 1936 (Siphonaptera: Ceratophyllidae) and transmission the plague pathogen by these fleas

Data obtained during feeding of Citellophilus tesquorum aitaicus Ioff, 1936 infested females and males (Siphonaptera: Ceratophyllidae), the main vectors of plague in Tuva natural plague locus, on the natural host and laboratory animal was analyzed. It was found that sexual differences in fleas depended on the type of the host. Females fed more actively on the longtailed ground Citellus undulatus than on white mouse. Alimentary activity of males on these animals was similar. Higher mortality of fed females and males was noted during feeding on mice. Frequency of formation of the "block" and transmission of the pathogen in males was higher during bloodsucking on the ground squirrel; in females, during feeding on mice. Thus, differences in the transmission of the plague pathogen, revealed in laboratory on white mice, can be quite different in nature. So, extrapolation of experimental data on natural processes of interrelations between plague pathogen and ectoparasites must be performed taking into account revealed peculiarities.     

Survey of numerical techniques for grouping

[This corrects the article on p. 379 in vol. 35.][This corrects the article on p. 381 in vol. 35.][This corrects the article on p. 384 in vol. 35.][This corrects the article on p. 387 in vol. 35.][This corrects the article on p. 388 in vol. 35.][This corrects the article on p. 389 in vol. 35.].     

Preliminary studies on the biology and host specificity of Aceria salsolae DeLillo and Sobhian (Acari, Eriophyidae) and Lixus salsolae Becker (Col., Curculionidae), two candidates for biological control of Salsola kali

Abstract: Preliminary studies on the biology and host specificity of the mite, Aceria salsolae DeLillo and Sobhian, and the weevil, Lixus salsolae Becker, were carried out in 1996 and 1997. The mite reproduced on Salsola kali L. from the USA and from Turkey (control), but not on the six species of closely related plants tested. Infected plants were stunted and did not produce flowers. The mite was found on plants in the fields in Turkey from May to October. Lixus salsolae adult feeding was heavy on most of the 10 plant species tested. The weevil reproduced only on S. kali from Turkey in 1996 and also on S. kali from California in 1997. The adults of the new generation emerged by mid-July and oviposition occurred on leaf petioles of Beta vulgaris (Swiss chard) but the emerging larvae died during very young stages. No oviposition and no infestation was observed on sugar beet plants in sugar beet fields in Turkey in 1996 and 1997, but infestations were found in a field in China in 1997.     

Transdifferentiation of "lentoid" structures in cultures derived from pigmented epithelium was inhibited by collagen.

Cells from pigmented retina of 8- to 9-day-old chick embryos were cultured under two different conditions: on noncoated (NS) or collagen-coated (CS) substrates. Although cells on CS seemed to start dividing 2 to 3 days earlier than those on NS, their early growth rates were basically similar. Cells on CS stopped growing after attaining confluency and formed a monolayer, while cells on NS continued to grow after confluency and overlapped each other. In early growth phase, cells on both substrates became depigmented. Cells became repigmented earlier on CS than on NS. The average melanin content of cells in confluent cultures on CS was two to three times higher than that of cells on NS. By Day 30 “lentoid bodies” were formed only in cultures on NS. Immunoelectrophoretic tests showed the presence of all crystallins (α-, β-, and δ) in cultures on NS but not in cultures on CS. It is concluded that a collagen substrate inhibits “transdifferentiation” of pigmented retinal cells into lens during cell culture.     

Cyclooxygenase and lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst

We have measured by radioimmunoassay the concentration and production of 5(S)-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), a metabolite in the lipoxygenase pathway, and PGs in different uterine compartments, and blastocysts during the preimplantation period in the rabbit. The production is defined as the synthesis minus the metabolism for a defined period of time. The pattern of uterine PGF production on days 5–6.5 was quite similar for the whole uterus and the myometrium showing a peak production on Day 6. The concentration and production of PGF were always higher in the endometrium. While significant production of PGE was noticed in the whole uterus on days 5–6 and in the myometrium on Day 6, the endometrium showed some production on these days. On the contrary, absolutely no production of this PG was observed in the endometrium on Day 6.5. The concentration and production of 6-keto-PGF_1α were always lower in the endometrium than those observed in the myometrium or the whole uterus. While highest production of this PG was found to be on Day 6.5 in the whole uterus and on Day 5 in the endometrium, the production in the myometrium remained constant on all days examined. The production of 5-HETE in the endometrium was noticeable on Days 5–6.5, in the whole uterus on Days 5 and 6.5, and in the myometrium only on Day 6.5. However, the concentrations of 5-HETE showed a tendency to be higher at 2 h than at 0 h in these compartments on Days 5–6.5. Furthermore, a linear increase in 5-HETE levels both 0 h and 2 h was observed in the endometrium on Days 5–6.5; no such differences in mean 5-HETE level was noted in the whole uterus or myometrium on any of these days. The production of 5-HETE in the blastocyst was noted only on Day 5. The results not only demonstrate the presence of both the cyclo-oxygenase and the lipoxygenase pathways in the preimplantation rabbit uterus and blastocyst, their differential operation in various compartments of the uterus on various days of early pregnancy suggests an integrated role for these mediators in embryo-uterine interaction during implantation.     

Coordinated peripheral neuronal activities among the different regions of the digestive tract in Aplysia

Peripheral neuronal somata are scattered throughout the enteric nervous system (ENS) in Aplysia. We found that somata on the outer surface of the digestive tract were more densely distributed on the stomatogastric ring and the posterior gizzard than on other regions. In preparations with or without the central nervous system, two types of synchronous bursting activity were recorded from the nerves of the ENS. Some of the synchronous bursts were recorded from nerves on the crop and stomatogastric ring, whereas others were recorded from nerves on the crop, stomatogastric ring, and gizzard. Experiments using preparations in which the different regions were separated suggested that the former bursts originated in neurons on the crop and the latter originated in neurons on the gizzard. Axonal projections of neurons on the different regions were examined by backfilling and analysis of the direction of impulse conduction. Blocking chemical synapses in separated gizzards depressed EPSP-like potentials and eliminated the bursting activities. When chemical synapses on the crop and stomatogastric ring but not on the gizzard were blocked in a whole digestive tract preparation, bursting activity recorded from nerves on all the regions was decreased, although the frequency of the bursting rhythm did not change. Stimulation of a neuron on the crop elicited bursts in nerves on the gizzard. These results suggest that chemical synaptic connections and a feedback loop along the digestive tract coordinate the synchrony of bursting activity originating in the gizzard.     

Substrate-dependent differences in growth and biological properties of fibroblasts and epithelial cells grown in microcarrier culture

Normal diploid human fibroblasts and first passage monkey kidney epithelial cells were examined for growth and metabolic activity on microcarriers made from glass and on microcarriers made from DEAE-dextran. The cells grew to a higher density (cells cm2 of surface area) on the glass microcarriers made from glass and on microcarriers made from DEAE-dextran. The cells grew to a higher density (cells/cm2 of surface area) on the glass microcarriers than they did on the DEAE-dextran microcarriers and morphological differences were observed between the cells growing on the two substrates. On the DEAE-dextran microcarriers, the cells were much more resistant to protease-mediated detachment than were the cells on the glass microcarriers. In these respects, the cells grown on the glass microcarriers were similar to cells grown in conventional monolayer culture. Interestingly, the cells grown on the DEAE-dextran microcarriers expressed higher levels of proteolytic enzyme activity than the cells grown on the glass microcarriers. Substrate-dependent differences in prostaglandin production also occurred--both in unstimulated cells and in cells stimulated with 12-0-tetradecanoyl phorbol acetate. The unstimulated cells on the glass microcarriers produced slightly higher levels of three different prostaglandins than did the cells on the DEAE-dextran microcarriers. However, after stimulation the levels were much higher in the DEAE-dextran microcarrier cultures than in the glass microcarrier cultures. In contrast to these results, there was no significant, substrate-dependent difference in the production of infectious herpes simplex virus. Taken together, these findings suggest that when commercially-useful cells such as normal fibroblasts and epithelial cells are grown in large quantities on microcarriers, the nature of the substrate may have a profound effect on the growth and physiology of the cells. They also suggest that when microcarriers are used, unexpected results based on preliminary work in conventional monolayer culture may be obtained.     

Regulation of adenylate cyclase activity and stimulation response in relation to endometrial receptivity in the rabbit

Adenylate cyclase activity was measured in broken cell preparations of whole endometrial tissue from rabbits on Days 0, 1, 6.5, 9 and 15 of pseudopregnancy and in endometrial epithelial and stromal cells on Days 1 and 6.5 to assess the specific response of individual cell types. In dispersed cells, adenylate cyclase activity was higher (P less than 0.01) in stromal than in epithelial cells and reduced on Day 6.5 compared to Day 1 in both cell types. The response of adenylate cyclase to isoproterenol appeared more important relative to the PGE-2 response in epithelial than in stromal cells and strongly reduced in the former on Day 6.5. In endometrium, the overall adenylate cyclase activity was increased significantly on Day 1 of pseudopregnancy compared to Day 0 (oestrus), only 18 h after injection of hCG. On the following days, the activity decreased progressively on Days 6.5 and 9 and exhibited a recovery on Day 15. Adenylate cyclase response to isoproterenol (% over GTP) was comparable on Days 0, 1 and 6.5, abolished on Day 9 and recovered on Day 15. Maximal response to PGE-2 (% over GTP) was observed on Day 6.5, at the time of implantation, maintained on Day 9 and reduced on Day 15 towards the low levels measured in oestrus and Day 1 of pseudopregnancy. Our results demonstrate a dramatic alteration of adenylate cyclase activity in rabbit endometrium during pseudopregnancy. It suggests a possible involvement of catecholamines and prostaglandin E-2 in the regulation of endometrial receptivity through a cAMP-mediated process.     

Growth and differentiation of opossum kidney cells on microscopically transparent microporous membranes

The growth and differentiation of opossum kidney cells on the recently-developed microscopically transparent microporous membrane are described. Confluent monolayers grown on membranes had twice the cell density of monolayers grown on plastic. Electron microscopy revealed junctional complexes in membrane-grown cells as well as in those cells grown on plastic. Cells grown on membranes, however, displayed more numerous and longer microvilli in addition to demonstrating a greater growth activity. There was an approximate two-fold increase in sodium-dependent phosphate transport per unit area by cells grown on membranes compared to the transport by cells grown on plastic. Phosphate transport by monolayers grown on both membranes and plastic was inhibited by parathyroid hormone (PTH).     

Vital statistics of Rhodnius neivai Lent, 1953 (Hemiptera: Reduviidae) under experimental conditions

A statistical evaluation of the population dynamics of R. neivai is based on six cohorts experiments conducted under controlled laboratory conditions. Two blood sources were offered to animals: rabbit and hen. Egg hatching, nymphal development time and mortality, adult longevity and age-specific mortality, female age-specific fecundity and fertility were determined. In addition, some population parameters were evaluated, such as: life expectancy, intrinsic rate of natural increase, net reproduction rate, finite rate of increase, reproductive value and stable age distribution. Life cycle was longer in the animals fed on rabbit, nymphal survival was slightly higher in the individuals fed on hen. Age of first reproduction was lower in the insects fed on hen, but reproductive output and total number of reproductive weeks were greater in the cohorts fed on rabbit. Intrinsic and finite rate of increase were greater in the animals fed on hen. Generation time was slightly greater in the cohorts fed on rabbit. Net reproduction rate was similar on both blood sources, although it was slightly bigger in the individuals fed on rabbit. Reproductive value in the insects fed on rabbit was twice as much as the registered in the animals fed on hen.