Ammonium versus Nitrate Nutrition of Plants Stimulates Microbial Activity in the Rhizosphere

Using an alkaline calcareous soil, pot experiments were conducted to elucidate the effects of NH ₄ ⁺ vs. NO ₃ ⁻ nutrition (50 or 100 mg kg⁻¹ soil) of wheat and maize on microbial activity in the rhizosphere and bulk soils. Dicyandiamide was used as nitrification inhibitor to maintain NH ₄ ⁺ as the predominant N source for plants grown in NH ₄ ⁺ -treated soil. While maize grew equally well on both N sources, root and shoot growth of wheat was higher under NH ₄ ⁺ than under NO ₃ ⁻ nutrition. Bacterial population density on roots, but not in the rhizosphere soil, was higher under NH ₄ ⁺ than under NO ₃ ^– supplied at 150 mg N kg⁻¹ soil; whereas at both N levels applied, NH ₄ ⁺ compared to NO ₃ ⁻ nutrition of wheat and maize significantly increased microbial biomass in the rhizosphere soil. Under both plant species, NH ₄ ⁺ vs. NO ₃ ⁻ nutrition also increased aerobic and anaerobic respiration, and dehydrogenase activity in the rhizosphere. As microbial activity in the planted bulk and unplanted soils was hardly affected by the N-source, we hypothesize that the stimulation by NH ₄ ⁺ of the rhizosphere microbial activity was probably due to higher availability of root exudates under NH ₄ ⁺ than under NO ₃ ⁻ nutrition.     

<Emphasis Type="Italic">Bipolaris hawaiiensis</Emphasis> Keratomycosis and Endophthalmitis

Following trauma with rice stalk to the left eye, corneal ulcer with abscess and hypopyon developed in an immunocompetent male. Direct examination of the corneal scrapings revealed septate, branched fungal hyphae. Bipolaris hawaiiensis was isolated after culture on blood agar and Sabouraud dextrose agar. Because of delay in diagnosis and appropriate treatment, the patient developed endophthalmitis needing evisceration.     

Unilateral hysterectomy (cornuectomy) in the bitch and its effect on subsequent fertility

During caesarean section of bitches a beginning tissue necrosis of the uterus is often encountered. These alterations mostly require ovariohysterectomy that means the end of breeding life. The aim of this study was to create a model for unilateral hysterectomy during dystocia and to evaluate subsequent fertility. Unilateral cornuectomy was performed in 18 clinically healthy bitches of different ages, breeds, and at different stages of the sexual cyclus. Four bitches were not available for follow-up examinations. Twelve bitches were mated at the first obvious estrus period postoperatively and 10 pregnancies were diagnosed. Nine bitches delivered one to five puppies (mean 3.8) after a gestation period of 63-67 days. The puppies (n=38) were in a very good condition and showed high vitality. Unilateral cornuectomy of the uterus had no adverse effects and postoperative mating revealed pregnancy without complications and normal parturition. In the case of pathological changes in one uterine horn during a caesarean section unilateral hysterectomy seems to be an alternative to ovariohysterectomy.     

黑尔衣属地衣2个中国新记录种

报道了采自新疆的黑尔衣属(Melanohalea)2个中国新记录种,分别为黑氏黑尔衣[M.halei(Ahti)O.Blanco et al.]和锯齿黑尔衣[M.laciniatula(Flagey ex H.Olivier)O.Blanco et al.],对其形态特征进行了详细描述并提供了形态解剖图片。     

Application of Zinc,Iron and Boron Enhances Productivity and Grain Biofortification of Mungbean

Deficiencies of essential vitamins, iron (Fe), and zinc (Zn) affect over one-half of the world’s population. A significant progress has been made to control micronutrient deficiencies through supplementation, but new approaches are needed, especially to reach the rural poor. Agronomic biofortification of pulses with Zn, Fe, and boron (B) offers a pragmatic solution to combat hidden hunger instead of food fortification and supplementation. Moreover, it also has positive effects on crop production as well. Therefore, we conducted three separate field experiments for two consecutive years to evaluate the impact of soil and foliar application of the aforementioned nutrients on the yield and seed biofortification of mungbean. Soil application of Zn at 0, 4.125, 8.25, Fe at 0, 2.5, 5.0 and B at 0, 0.55, 1.1 kg ha⁻¹ was done in the first, second and third experiment, respectively. Foliar application in these experiments was done at 0.3% Zn, 0.2% Fe and 0.1% B respectively one week after flowering initiation. Data revealed that soil-applied Zn, Fe and B at 8.25, 5.0 and 1.1 kg ha⁻¹, respectively, enhanced the grain yield of mungbean; however, this increase in yield was statistically similar to that recorded with Zn, Fe and B at 4.125, 2.5 and 0.55 kg ha⁻¹, respectively. Foliar application of these nutrients at flower initiation significantly enhanced the Zn contents by 28% and 31%, Fe contents by 80% and 78%, while B contents by 98% and 116% over control during 2019 and 2020, respectively. It was concluded from the results that soil application of Zn, Fe, and B enhanced the yield performance of mungbean; while significant improvements in seed Zn, Fe, and B contents were recorded with foliar application of these nutrients.     

Adaptation of a luciferase gene reporter and lac expression system to Borrelia burgdorferi

The development of new genetic systems for studying the complex regulatory events that occur within Borrelia burgdorferi is an important goal of contemporary Lyme disease research. Although recent advancements have been made in the genetic manipulation of B. burgdorferi, there still remains a paucity of basic molecular systems for assessing differential gene expression in this pathogen. Herein, we describe the adaptation of two powerful genetic tools for use in B. burgdorferi. The first is a Photinus pyralis firefly luciferase gene reporter that was codon optimized to enhance translation in B. burgdorferi. Using this modified reporter, we demonstrated an increase in luciferase expression when B. burgdorferi transformed with a shuttle vector encoding the outer surface protein C (OspC) promoter fused to the luciferase reporter was cultivated in the presence of fresh rabbit blood. The second is a lac operator/repressor system that was optimized to achieve the tightest degree of regulation. Using the aforementioned luciferase reporter, we assessed the kinetics and maximal level of isopropyl-beta-D-thiogalactopyranoside (IPTG)-dependent gene expression. This lac-inducible expression system also was used to express the gene carried on lp25 required for borrelial persistence in ticks (bptA). These advancements should be generally applicable for assessing further the regulation of other genes potentially involved in virulence expression by B. burgdorferi.     

Melanocyte-keratinocyte interaction induces calcium signalling and melanin transfer to keratinocytes

Physical contact between melanocytes and keratinocytes is a prerequisite for melanosome transfer to occur, but cellular signals induced during or after contact are not fully understood. Herein, it is shown that interactions between melanocyte and keratinocyte plasma membranes induced a transient intracellular calcium signal in keratinocytes that was required for pigment transfer. This intracellular calcium signal occurred due to release of calcium from intracellular stores. Pigment transfer observed in melanocyte-keratinocyte co-cultures was inhibited when intracellular calcium in keratinocytes was chelated. We propose that a 'ligand-receptor' type interaction exists between melanocytes and keratinocytes that triggers intracellular calcium signalling in keratinocytes and mediates melanin transfer.     

Seed treatment with growth regulators and crop productivity. I. 2,4-D as an inducer of salinity-tolerance in wheat (Triticum aestivum L.)

The paper investigates how the apoplastic route of ion transfer is affected by the outermost cortex cell layers of a primary root. Staining of hand-made cross sections with aniline blue in combination with berberine sulfate demonstrated the presence of casparian bands in the endo- and exodermis, potentially being responsible for hindering apoplastic ion movement. The use of the apoplastic dye Evan's Blue allowed viewing under a light microscope of potential sites of uncontrolled solute entry into the apoplast of the root cortex which mainly consisted of injured rhizodermis and/or exodermis cells. The distribution of the dye after staining was highly comparable to EDX analyses on freeze-dried cryosectioned roots. Here, we used Rb+ as a tracer for K+ in a short-time application on selected regions of intact roots from intact plants. After subsequent quench-freezing with liquid propane the distribution of K+ and Rb+ in cell walls was detected on freeze-dried cryosections by their specific X-rays resulting from the incident electrons in a SEM. All such attempts led to a single conclusion, namely, that the walls of the two outermost living cell sheaths of the cortex largely restrict passive solute movements into the apoplast. The ring of turgescent living rhizodermis cells in the root tip region forms the first barrier. With increasing distance to the root tip, in the course of their maturation resp. degradation, this particular function of the rhizodermis cells is replaced by the hypodermis resp. exodermis. Furthermore, the restriction of apoplastic ion flow by the outermost cortex cell layers is rather effective but not complete. Thus, the solute transfer into the stele is mainly restricted by the casparian bands of the endodermis. The overall conclusion is that the resistances of the rhizodermis and exodermis are additive to the endodermis in their role of regulating the apoplastic solute movement across roots. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis,modification, and cytotoxic evaluation of 2,3-secotriterpenic β-ketoesters

A set of β-ketoesters was synthesized from 2,3-seco-18αH-oleanane and 2,3-secolupane bromomethyl ketones. Additionally, hydroxy derivatives with the A-seco- or five-membered A ring were obtained as a result of the reduction or of alkaline hydrolysis of acetic acid β-ketoesters 4, 9. Cytotoxic screening revealed the compound 4 with marked activity (IC₅₀ 3.07–3.61?µM) against the HCT 116, MS, RD TE32 cancer cells. The studies of the cytotoxic mechanism enabled elucidating the fact that treatment of the HCT 116 cells with compound 4 for 18?h leads to induction of apoptosis in a dose-dependent manner. This observation was confirmed by registration of chromatin condensation, by the fluorescence increased during Annexin V-FITC staining, and by appearance of a sub-G0 peak in the cell cycle analysis with DAPI. Compound 4 also inhibited migration of cancer cells in the wound healing assay.