Seminal Root Growth in Sorghum (Sorghum bicolor) Under Allelopathic Influences from Residues of Taro (Colocasia esculenta)

The length of the seminal root (SR) axis and the number andlength of lateral roots (LRs) of sorghum (Sorghum bicolor Moench)were markedly inhibited by taro [Colocasia esculenta (L.) Schott]residues incorporated into a sand growing medium. The sand profilewas divided equally into zones with and without residues. Productionand elongation of the first-order LRs of the SR axis facingthe zone containing taro residues were severely suppressed.On the side facing the zone that was free of residues, productionand elongation of LRs was not inhibited. SR and LR growth wasdrastically impaired and many plants were killed when taro residueswere incorporated in large amounts into the uppermost 2 cm ofthe growing medium. The activity of the allelopathic substancesin the root zone appeared to be location-specific. Sorghum bicolor, seminal root, lateral root, Colocasia esculenta, taro, taro residues, allelopathic substances, root growth     

Time Lapse Analysis of Root Elongation Rates of Rice and Sorghum During the Day and Night

This paper describes a technique to monitor the root elongationrate (RER) per hour for several days, and variation in RER duringthe day and night. Rice (Oryza sativaL.) and sorghum (SorghumbicolorMoench) were grown in root boxes placed inside a growthchamber set at 25 °C with a 12 h photoperiod. Seminal rootaxes were sandwiched between a transparent acrylic board andfilter paper placed on a loamy sand soil. The roots were photographedunder dim green light using a CCD camera connected to a timelapse video recorder. The environment of the root, includingtemperature, light, nutrient, water and air supply, was controlledprecisely and maintained constant. RER fluctuated hourly insorghum and to a greater extent in rice. Maximum RERs were 1.4to 4.4 times faster than minimum rates. RERs during the dayand night did not differ statistically when temperatures werethe same.Copyright 1998 Annals of Botany Company Oryza sativaL., periodicity, root elongation,Sorghum bicolorMoench, time lapse.     

The shape of things to come: linking developmental plasticity to post‐metamorphic morphology in anurans

Development consists of growth and differentiation, which can be partially decoupled and can be affected by environmental factors to different extents. In amphibians, variation in the larval environment influences development and causes changes in post‐metamorphic shape. We examined post‐metamorphic consequences, both morphological and locomotory, of alterations in growth and development. We reared tadpoles of two phylogenetically and ecologically distant frog species (the red‐eyed treefrog Agalychnis callidryas and the African clawed frog Xenopus laevis) under different temperatures with ad libitum food supply and under different food levels at a constant temperature. Low temperature and low food levels both resulted in similarly extended larval periods. However, low temperature yielded relatively long‐legged frogs with a lower degree of ossification than warm temperature, whereas low food yielded relatively short‐legged frogs with a higher degree of ossification than high food levels. Such allometric differences had no effect on locomotor performance of juveniles. Our results provide a basis for understanding the relationship between growth, differentiation and post‐metamorphic shape in anurans and help explain many of the discrepancies reported in previous studies.     

Left-handed Helical Polynucleotides with D-Sugar Phosphodiester Backbones

Naturally occurring polynucleotides have right-handed helical confrontations in the solid state¹ and in solution². Poly(dI-dC)poly(dI-dC) was found to form a left-handed helix in spite of the D-sugar backbone. Also, L-adenylyl-(3′–5′)-L-adenosine synthesized by Tazawa et al⁴. takes up the left-handed stacked conformation. We had synthesized a dinucleoside monophosphate, 8,2′-anhydro-8-mercapto-9-β-D-arabinofuranosyladenine phosphoryl-(3′–5′)-8,2′-anhydro-8-mercapto-9-β-D-arabinofuranosyladenine (A^spA^s) (molecular structure Ia; see also ref. 5) and this compound has a left-handed stacked conformation. The two bases in Ia, having the D-sugar backbone, stacked along the left-handed helical axis; these bases are fixed at ?_CN = ?108° (syn-anti region) by the anhydro linkages.     

Development of Golgi Apparatus in the Root Cap Cells of Maize (Zea mays L.) as Affected by Compacted Soil

Effects of soil mechanical impedance on the development of Golgiapparatus in the root cap cells of maize were studied undercontrolled soil-water conditions Heavily compacted soil (bulkdensity = 1.50 g cm^–2) had 3.3 to 3.4 times greater mechanicalimpedance than control soil (bulk density = 1.33 g cm^–3),but their oxygen diffusion rates were not significantly differentThe number of dictyosomes and the number and area of secretoryvesicles per unit area of tangentially sub-peripheral root capcells in the heavily compacted soil increased compared to thosein the control These results suggest that secretory activityof the root cap cells is promoted by soil mechanical impedance Dictyosome, Golgi apparatus, maize, mucilage, root cap, secretory activity, secretory vesicles, soil mechanical impedance, Zea mays L     

ELECTRON MICROSCOPIC STUDIES ON THE OOGENESIS OF DRAGONFLY AND CRICKET WITH SPECIAL REFERENCE TO THE PANOISTIC OVARIES

The successive ultrastructural changes during oogenesis in Sympetrum frequens (Odonata, Libellulidae) and Gryllus yemma (Orthoptera, Gryllidae) were studied.
The structures of the terminal filament and boundary between the terminal filament and the germarium differed from each other in these 2 species; in Sympetrum the boundary between the terminal filament and the germarium was a special acellular transverse septum, whereas that in Gryllus was composed of several flattened cells which seemed to be similar to the prefollicular cells in the germarium.
During the previtellogenesis, the nucleolar extrusions and emissions of the outer nuclear envelope were observed frequently in young oocytes. In Sympetrum , electron dense masses were observed in the oocyte cytoplasm, which seemed to be "yolk nuclei" or "Balbiani bodies" and were composed of aggregated small particles (about 200 A in diameter). They were gradually dispersed in the cytoplasm until the onset of vitellogenesis.
In both Sympetrum and Gryllus , yolk precursors seemed to be incorporated into oocytes by micropinocytosis as observed in various animals.
The egg membranes, viz. , the vitelline membrane and the chorion, seemed to be formed by products from follicle cells which developed rough-surfaced endoplasmic reticulum and Golgi bodies. Thus, both of these egg membranes were assumed to be the secondary egg membranes.     

Generation of multivirus-specific T cells by a single stimulation of peripheral blood mononuclear cells with a peptide mixture using serum-free medium

Background: Restoration of virus-specific immunity by virus specific T cells (VSTs) offers an attractive alternative to conventional drugs, and can be highly effective in immunocompromised patients, including hematopoietic stem cell transplant (HSCT) recipients. However, conventional VSTs manufacture requires preparation of specialized antigen-presenting cells (APCs), prolonged ex vivo culture in serum-containing medium and antigen re-stimulation with viruses or viral vectors to provide viral antigens for presentation on APCs. Methods: To simplify this complex process, we developed a method to generate multiple VSTs by direct stimulation of peripheral blood mononuclear cells (PBMCs) with overlapping peptide libraries in serum-free medium. Results: We generated VSTs that targeted seven viruses (cytomegalovirus [CMV], Epstein-Barr virus [EBV], adenovirus [AdV], human herpesvirus 6 [HHV-6], BK virus [BKV], JC virus [JCV] and Varicella Zoster virus [VZV]) in a single line. The phenotype, growth and specificity of multiple VSTs produced in serum-free medium were equivalent to those generated in conventional serum-containing medium. Discussion: The use of serum-free medium allows this approach to be readily introduced to clinical practice with lower cost, greater reproducibility due to the absence of batch-to-batch variability in serum and without concerns for infectious agents in the serum used. This simplified approach will now be tested in recipients of Human Leukocyte Antigen (HLA)–matched sibling HSCT.     

Sloughing of cap cells and carbon exudation from maize seedling roots in compacted sand

Sloughing of root cap cells and exudation of mucilage plays an important role in the penetration of compacted soils by roots. For the first time we have quantified the rate of sloughing of root cap cells in an abrasive growth medium that was compacted to create mechanical impedance to root growth. The number of maize ( Zea mays ) root cap cells sloughed into sand increased as a result of compaction, from 1930 to 3220 d⁻¹ per primary root. This represented a 12-fold increase in the number of cells sloughed per mm root extension (from 60 to >700). We estimated that the whole of the cap surface area was covered with detached cells in compacted sand, compared with c . 7% of the surface area in loose sand. This lubricating layer of sloughed cells and mucilage probably decreases frictional resistance to soil penetration. The total carbon deposited by the root was estimated at c . 110 μg g⁻¹ sand d⁻¹. Sloughed cells accounted for <10% of the total carbon, the vast majority of carbon being contained in mucilage exudates.     

Observations on the Taiwanese Strain of Leucocytozoon caulleryi (Haemosporina) in Chickens

ABSTRACT. The Taiwanese strain of Leucocytozoon caulleryi was isolated from an infected chicken in Taipei, Taiwan, and established in chickens and biting midges Culicoides arakawae from Japan. Sporogony of the strain in C. arakawae was completed on day 3 after the infective blood meals at 25°C. Sporozoites isolated from the salivary glands of C. arakawae on days 3 or 4 after feeding caused infection in all the chickens inoculated. The strain showed high pathogenicity for chickens. Mortality of chickens rose with an increase in the number of sporozoites inoculated. The prepatent period for chickens inoculated with sporozoites was 14 days. Parasites appeared in the peripheral blood of chickens on day 15 and disappeared on day 26 after sporozoite inoculation. Soluble antigens were found in the sera of chickens infected with the strain between 10 and 17 days after inoculation, and homologous antibodies appeared after 17 days. Antigens prepared from sera, schizonts, merozoites, and gametocytes of the Taiwanese strain reacted with the sera of chickens infected witt the same strain or the strain isolated in Japan. The chickens that recovered from a primary infection with the Taiwanese strain demonstrated complete resistance to reinfection with the same strain or the strain isolated in Japan.