Promotion of respiration by auxin in the induction of cell division in suspension culture

Auxins (IAA, NAA, p-CPA) caused 20–30% promotion of respiration of auxin-dependent cell cultures ofNicotiana tabacum, Glycine max, Taraxacum mongolica, andAtriplex sp. and had small if any effect on respiration of auxin-independent cell cultures ofRubus sp. andScorzonera hispanica. Antiauxin (p-CPIBA) did not affect the respiration. The auxin effect on the respiration of tobacco cells was revealed 10 min after its addition to the suspension and reached a maximum value in 60 min. This stimulation preceded the induction of cell division by auxin. Mitochondria isolated from auxin-treated tobacco cells had greater oxidative and phosphorylative activity than mitochondria from untreated cells. However, isolated mitochondria did not respond to auxin. The inhibitors of respiration (cyanide, monoiodoacetate, malonate, and 2,4-dinitrophenol) eliminated auxin effect on the respiration and cell division. It is concluded that the promotion of respiration is a common event for the auxin effects both on cell extension and on cell division. This promotion is necessary for the induction of cell division and is exerted via direct activation of mitochondriain situ.     

Parasites ofSpodoptera exigua,S. eridania [Lep.: Noctuidae] andHerpetogramma bipunctalis [Lep.: Pyralidae] collected fromAmaranthus hybridus in field corn

Three species of lepidopterous larvae were collected fromAmaranthus hybridus L. growing in field corn during 1975 and 1976 at Hastings, Florida.Spodoptera exigua (Hubner) was the predominant species in May.Spodoptera eridania (Cramer) was predominant in June andHerpetogramma bipunctalis (F.) in July and August. Nine native species of parasites, representing theBraconidae, Eulophidae, Ichneumonidae andTachinidae, emerged from these larvae.Meteorus autographae Muesebeck emerged from bothS. exigua andS. eridania. TheTachinidae, Winthemia rufopicta (Bigot),Eucelatori rubentis (Coquillett) andLespensia sp., emerged from mixtures ofS. exigua andS. eridania. Apanteles marginiventris (Cresson),Temelucha sp., andChelonus texanus Cresson emerged from bothS. exigua andH. bipunctalis larvae, andEuplectrus platyhypenae Howard andOphion sp. emerged fromS. eridania. All the species of parasites from the lepidopterous larvae that feed onAmaranthus hybridus are also reported as parasites ofS. frugiperda, a serious pest of corn. Therefore these larvae onA. hybridus may be a source of the parasites found attackingS. frugiperda.     

Auxin activity of phenylacetic acid in tissue culture

The ability of phenylacetic acid (PAA), a naturally occurring auxin, to initiate and support growth of callus and suspension cultures of several species is reported. Callus tissue of tobacco (Nicotiana tabacum L. var. WI-38), initiated and maintained on a medium with 2,4-dichlorophenoxyacetic acid (2,4-D), was transferred to and maintained on media supplemented with 25–500 μM PAA as the only plant growth regulator (PGR). Optimal concentrations of PAA were determined for tobacco callus proliferation in the dark (250 μM PAA) and with a 16-h light/8-h dark photoperiod (500 μM PAA). Tobacco suspension cultures were maintained for over 28 transfers in media containing 20–40 μM PAA as the sole PGR. When tobacco callus tissue maintained on PAA-supplemented media for over 18 months was transferred to liquid media containing kinetin, plantlets were regenerated. Callus of sunflower (Helianthus annuus L. var. Russian Mammoth) proliferated on media containing PAA at 5–250 μM as the sole PGR. Similar PAA concentrations inhibited normal development and promoted callus formation in tobacco and pea (Pisum sativum L. vars. common, Frogel, and Frimas) epicotyl tissue. PAA as the sole PGR did not support the growth of soybean (Glycine max (L.) Merrill var. Fiskeby) callus or suspension cultures. Chickpea (Cicer arietinum L. var. UC-5) and lentil (Lens culinaris Medic. var. Laird) callus cultures proliferated on media containing 25–500 μM PAA, but habituation of the cultures was common. PAA was not toxic to tobacco, chickpea, and lentil tissues at levels as high as 500 μM.     

Biogenesis of mitochondria 20 the effects of altered membrane lipid composition on mitochondrial oxidative phosphorylation inSaccharomyces cerevisiae

1. The lipid composition of mitochondria isolated from a fatty acid desaturase mutant ofSaccharomyces cerevisiae may be extensively manipulated by growing the organism on defined supplements of unsaturated fatty acid (UFA).
2. The fatty acid composition of the mitochondrial lipids closely follows that of the whole cells from which the mitochondria are isolated. UFA-depleted mitochondria contain normal levels of sterols, neutral lipids and total phospholipids, but have much lower levels of phosphatidyl inositides.
3. UFA-depleted mitochondria possess a full complement of cytochromes, oxidase both NAD-linked and flavoprotein-linked substrates at normal rates, and have levels of succinate and malate dehydrogenases similar to those of UFA-supplemented mitochondria. However, UFA-depletion has a marked effect on the ability of cytochromec to reactivate the NADH oxidase activity of cytochromec-depleted mitochondria.
4. The efficiency of oxidative phosphorylation decreases progressively with the UFA content of the mitochondria, and oxidative phosphorylation is completely lost in mitochondria containing approximately 20% UFA.
5. The incorporation of UFA into the lipids of UFA-depleted mitochondriain vivo results in a recoupling of oxidative phosphorylation. Recoupling is insensitive to both chloramphenicol and cycloheximide, indicating that all the proteins necessary for oxidative phosphorylation are present in UFA-depleted mitochondria, and that the less of oxidative phosphorylation is a purely lipid lesion.
6. ATPase activity is apparently unaffected by UFA-depletion, but³²P_i-ATP exchange activity is lost in mitochondria which have been extensively depleted in UFA.
7. Valinomycin stimulates the respiration of UFA-supplemented mitochondria in media containing potassium, but has no effect on the respiration of UFA-depleted mitochondria, suggesting that active transport of potassium is lost as a result of UFA-depletion.

     

Cytogenetic studies in mammalian cells after treatment with insect pathogenic viruses [Baculoviridae]. II.In vitro studies with mammalian cell lines

Mammalian cell-lines from Chinese hamster, Indian muntjac and mouse were inoculated with infectious supernatant ofAutographa californica (Speyer) nuclear polyhedrosis virus (Ac NPV) replicated inMamestra brassicae (L.) cell cultures (IZD-Mb-0503). There was no adverse effect on cell proliferation, nor was a cytopathogenic effect (CPE) induced in such cultures. Cytogenetic data indicate that uptake ofAc-NPVs into the cytoplasm of mammalian cells, as shown by an electron microscopic study, induced neither numerical or structural chromosome aberrations nor sister chromatid exchange (SCE) events.     

The establishment ofAnagyrus saccharicola Timb. [Hymenoptera: Encyrtidae] in Barbados,West Indies,against the sugarcane mealybug,Saccharicoccus sacchari (Ckll.) (Hemiptera: Coccidae]

During the survey of the natural enemies ofSaccharicoccus sacchari in Barbados in 1968 and 1969, the following six indigenous species of natural enemies were recorded: —Hyperaspis trilineata andNephus sp.(Coccinellidae); Oligota barbadorum (Staphylinidae); an unidentified Cecidomyid(Cecidomyidae); Pseudaphycus mundus (Encyrtidae) andAspergillus sp. (Aspergillacae). Of these,H. trilineata was found in fair numbers in the Westmoreland (St. James) area only;Aspergillus sp. was more abundant during the wet season, while the other species were recorded usually in small numbers from most parishes. As the indigenous natural enemies do not provide effective control of the pest, three exotic predators and one parasite were introduced into Barbados, through the Commonwealth Institute of Biological Control.Cryptolaemus montrouzieri, Hyperaspis sp. andNephus sp. were obtained from India andAnagyrus saccharicola from East Africa. OnlyA. saccharicola became established. It was recovered soon after its release and, augmented by additional releases, spread rapidly. In January 1972, the levels of parasitism in the dry, intermediate and high rainfall areas were: 8.3, 9.0 and 9.7%.     

Enhanced plumbagin accumulation in embryogenic cell suspension cultures of Plumbago rosea L. following elicitation

This study focused on enhancing the production of plumbagin, an anticancer compound, in embryogenic cell suspension cultures of Plumbago rosea. Elicitation techniques have been reported to enhance plumbagin production. Cell suspension cultures raised from embryogenic calli induced from in vitro leaf explants were exposed to different concentrations of jasmonic acid, yeast extract and different auxin combinations. Influence of these on cell growth, biomass and plumbagin production was studied. To our knowledge this is the first report on elicitation of embryogenic cell suspension cultures of P. rosea for enhanced plumbagin production. Elicitor treated suspension cultures exhibited decreased culture viability and increased plumbagin synthesis. A maximum of 5.59-fold enhancement of plumbagin production was observed in cultures added with 1 mg L^?1 naphthalene acetic acid after 6 days of incubation. Viability of cultures decreased with increased concentration of elicitors and prolonged incubation period. Application of elicitors in cell suspension cultures induces defense related responses which lead to increased secondary metabolite production for making the cells adapt to the situation. If the stressed condition persists or is in intolerable level this will eventually lead to programmed cell death and loss of culture viability.     

Function of the aux and rol genes of the Ri plasmid in plant cell division in vitro

Auxin-autonomous growth in vitro may be related to the integration and expression of the aux and rol genes from the root-inducing (Ri) plasmid in plant cells infected by agropine-type Agrobacterium rhizogenes. To elucidate the functions of the aux and rol genes in plant cell division, plant cell lines transformed with the aux1 and aux2 genes or with the rolABCD genes were established using tobacco (Nicotiana tabacum) Bright Yellow-2 (BY-2) cells. The introduction of the aux1 and aux2 genes enabled the auxin-autonomous growth of BY-2 cells, but the introduction of the rolABCD genes did not affect the auxin requirement of the BY-2 cells. The results clearly show that the aux genes are necessary for auxinautotrophic cell division, and that the rolABCD genes are irrelevant in auxin autotrophy.Key words: Agrobacterium rhizogenes, auxin-autotrophic cell, auxin biosynthesis, hairy root, plant cell division, Ri plasmid, T-DNA, aux, rol, tobacco BY-2 cells     

Degradation and turnover of bacterial cell wall mucopeptides in growing bacteria

The mucopeptide layer of the cell wall ofBacillus megaterium is broken down into separate components during growth of the cells. The released diaminopimelic acid is partly decarboxylated to lysine, which is incorporated in the proteins and partly used for cell wall resynthesis. The smaller portion of the degraded mucopeptide is released into the medium in the form of non-utilized fragments. The rate of the mucopeptide turnover is a function of the rate of growth of the culture. About 15–20% of the rigid layer of the cell wall is degraded during on cell division. The sensitivity ofBacillus megaterium to lysozyme and the rate of its conversion to protoplasts is also proportionate to the rate of growth of the culture. There is no measurable mucopeptide turnover in non-growing cells, either in the stationary phase of the culture or in starvation in nitrogen-free medium. The resistance of the cell wall to lysozyme also increases during the stationary phase. The rigid component of the cell wall is probably also broken down during growth ofBacillus cereus andEscherichia coli cultures.     

Effect of benzylaminopurine and thidiazuron onin vitro shoot proliferation ofTilia cordata MILL.,Sorbus aucuparia L. andRobinia pseudoacacia L.

Benzylaminopurine and thidiazuron stimulated shoot proliferation ofTilia, Sorbus andRobinia. Low concentration of BAP (0.2—1.0 mg I^?1) promoted axillary bud formation and shoot elongation. Thidiazuron displayed high cytokinin activity at very low concentrations (0.002—0.05 mg I^?1). Shoot number induced on media containing thidiazuron was large. Numerous shoots were produced on the media containing BAP together with thidiazuron. Shoots produced on media containing thidiazuron or BAP together with thidiazuron rooted after transfer to medium supplemented with low concentration of auxin (IBA or NAA).     

Parasites ofEctomyelois ceratoniae with biological studies onApanteles sp.Group ultor in Iraq

Apanteles sp.group ultor [Hym.: Braconidae] is the dominant and most widely distributed parasite ofEctomyelois ceratoniae (Zeller). The parasitization percent was increased from 10 % during April to 35 % at the end of the pomegranate fruiting season at October. Female parasite preferred to infest the host larvae at the age of, 2–3 days than 7 day old. The average number of host larvae parasitized by single female parasite was 58 under the rearing conditions of 27±2 °C., 55±10% RH and photoperiod of 16 h light per day. Parasites other thanA. spgroup ultor were:Bracon hebetor Say.,Ascogaster sp., andPhanerotoma sp. [Braconidae];Nemeritis canescens Grav. [Ichneumonidae];Brachymeria sp., andB. aegyptiaca Masi [Chalcididae]; and the secondary parasitePerilampus tristis Mayr [Perilampidae].     

Circadian chronotypic death in heat-synchronized infradian mode cultures ofTetrahymena pyriformis W.

Continuous cultures ofTetrahymena pyriformis in the infradian (“slow-exponential”) growth mode can be entrained to give circadian rhythms of cell division by the application of thermal cycles with periods of 24 hr. The degree of synchronization (phasing index) is dependent on the cycling of other environmental agents, particularly food in the form of the defined medium used. The phase angles of these multiple zeitgebers to one another and to the circadian cell cycle markedly influence the quality of synchronization achieved. In wellsynchronized oxygen-limited cultures, a circadian cytotoxia (circadian chronotypic death) is observed when the culture's oxygen requirements periodically exceed the oxygen support limit of the environment.     

Species of Nectria (Ascomycetes,Hypocreales) having orange perithecia and colorless,striate ascospores

Nine species ofNectria are described or redescribed. Ascospores of all are colorless and striates; their perithecia are orange and do not become red in KOH. Three groups of species are represented. One group includesNectria grammicospora, N. cf.grammicospora, N. subquaternata, and the new species:N. grammicosporopsis, N. lucifer, andN. neogrammicospora. A second group includes the new speciesN. chlorogloea andN. septomyrotheciae. The third group is represented by the single new speciesN. dacryocarpa. The life-cycles of these species are described. Anamorphs ofN. grammicospora, N. grammicosporopsis, N. lucifer, andN. subquaternata are species ofClonostachys. The anamorph, ofN. neogrammicospora isAcremonium- orCephalosporiopsis-like in having monophialidic conidiophores and phragmosporous conidia, and that ofN. cf.grammicospora isAcremonium-like with amerosporous conidia. The anamorphs ofN. chlorogloea andN. septomyrotheciae have green conidia. The anamorph ofN. chlorogloea isMyrothecium sp.; its conidia are unicellular and the conidioma is a synemma. The anamorph ofN. septomyrotheciae isSeptomyrothecium cf.uniseptatum; its conidioma is a sporodochium and the conidia are bicellular. The new genus and speciesDacryoma alba are described for the anamorph ofN. dacryocarpa. All of these fungi are pantropical or Australasian in distribution.     

Biological control ofMythimna separata [Lep.: noctuidae] in New Zealand and its bearing on biological control strategy

A survey of parasites ofAgrotis spp. was carried out in Pakistan to find promising species for trial against noctuids especiallyAgrotis spp. andMythimna separata (Walker) in New Zealand. The parasites recorded wereApanteles ruficrus Haliday,Macrocentrus collaris Spinola,Periscepsia carbonaria Panzer,Turanogonia smirnovi,Rohdain,Ctenichneumon panzeri Wesmael andAnthrax sp. All exceptAnthrax sp. were supplied to New Zealand whereA. ruficrus andM. collaris were released in large numbers.A. ruficrus became established and is giving excellent control ofM. separata resulting in enormous economic gains. Recently it has also been recovered fromAgrotis spp. This example of biological control is significant in thatM. separata has been controlled by a parasite that was previously known from it in New Zealand. The specific status of the “A. ruficrus” already present in New Zealand requires investigation.     

Analysis of theilv-linked genes that determine the morphology ofEscherichia coli Cells

The genetic location ofwee relative tocya was measured by cotransduction with a Tn5 insertion inilv. These experiments locatedwee at 84.8 min in the standardEscherichia coli map. Mutations incya andwee give rise to morphological changes, coccal morphology incya and short rods inwee, suggesting that both may be involved in the pathways of cell elongation. Addition of cAMP to the cultures reverted thecya but not thewee phenotype. Cells ofE. coli in the absence of thewee gene product were, contrary to what has been described forcya cells, as sensitive to mecillinam as in its presence. These results suggested that the action of Wee on elongation is exerted at a level different from that of adenyl cyclase.     

Description ofOligosita tominici n. sp. [Hym., trichogrammatidae] and notes on the hosts ofAnagrus atomus (L.) andAnaphes autumnalis Foerster [Hym. Mymaridae]

Oligosita tominici n. sp. is described, bred fromErythroneura eburnea (Cicadellidae) and a key to theminima-group is given.Anagrus atomus (L.) is recorded fromErythroneura eburnea, too, andAnaphes autumnalis Foerster is bred from an egg ofTipula autumnalis Loew; it is the first record of an egg-parasite ofTipulidae.     

Cutlassfishes of the genusLepidopus (Trichiuridae), with two new eastern pacific species

Three of the five known species ofLepidopus occur in the eastern Pacific.Lepidopus manis sp. nov. is described from a single specimen from the Galápagos Islands. The holotype ofL. xantusi Goode et Bean, 1895, supposedly from Cape San Lucas, Lower California, is shown to be conspecific withL. caudatus (Euphrasen, 1788). The species heretofore reported under the nameL. xantusi is described, and namedL. fitchi sp. nov. It ranges from Oregon to the Gulf of California and occurs disjunctly in southern Ecuador and northern Peru. A key to the described species ofLepidopus is given and certain morphological features ofL. caudatus are described. Geographic variability ofL. caudatus andL. fitchi is discussed.     

Isolation and description of a non-motile,fusiform, stalked bacterium,a representatieve of a new genus

A single strain representing the fusiform group of caulobacters first described by Henrici and Johnson has been isolated from a freshwater pond. Like the genusCaulobacter this is a chemo-organotrophic bacterium that has one polar prostheca, a stalk in the sense that its apical holdfast permits the cell to attach to solid substrates. Fine structure studies reveal, however, that the prostheca of this organism contains typical cellular constituents, not the membranous material found in the stalks ofCaulobacter andAsticcacaulis. The organism also differs from the other caulobacters in having no motile stage and no dimorphic life cycle (both daughter cells are stalked at the time of division). Because only one strain has been isolated no nomenclatural proposals are made, but sufficient evidence is presented to indicate that this is a representative of a new genus of the Schizomycetes.