Zoo-FISH with microdissected arm specific paints for HSA2, 5, 6, 16, and 19 refines known homology with pig and horse chromosomes

Microdissected arm specific paints (ASPs) for human (HSA) chromosomes (Chrs) 2, 5, 6, 16, and 19 were used as probes on pig (SSC) and horse (ECA) metaphase chromosomes. Regions homologous to individual human arms were delineated in the two species studied. Of the ten ASPs used, HSA6 and 16 ASPs showed complete synteny conservation of individual arms as single blocks/arms both in pig and horse. A similar trend was, in general, also observed for HSA19 ASPs. However, contrary to these observations, synteny conservation of individual arms of HSA2 and HSA5 was not observed in pig and horse. The arm specific painting data, coupled with the available gene mapping data, showed that, although HSA2 corresponded to two arms/chromosomes each in pig and horse, the breakpoint of this synteny in humans was not located at the centromere, but at HSA2q13 band. Similarly, arm specific paints for HSA5 showed that of the two blocks/chromosomes painted in pig and horse, one corresponded to HSA5q13-pter, the other to HSA5q13-qter. The findings suggest that 5q13 band may also be an evolutionary break point, similar to the one detected on HSA2q13. The microdissected human arm specific painting probes used in the present work provide more accurate and refined comparative information on pig and horse chromosomes than that available through the use of human whole chromosome specific paints. Received: 1 June 1997 / Accepted: 5 September 1997     

Effect of certain environmental factors on zygospore germination ofSpirogyra hyalina

The present study focusses on the effects of pH, temperature, intensity of white, red far-red light on zygospore germination in the filamentous green algaSpirogyra hyalina. Maximum germination of zygospores occurred at pH 8.0 and 25°C. Germination of zygospores was favored by white light at an intensity of 3–4 klx. Red light resulted in higher germination when applied at the beginning or in the middle of the dark period, while far-red light decreased zygospore germination. Red light in the middle of the dark period was found to be most effective for germination. These observations suggest a possible presence of the phytochrome system in the test alga contributing to its morphogenetic response.     

Studies of mediator involvement in cooling-induced alterations of guinea pig tracheal smooth muscle contractility

Heat loss from airway smooth muscle is a potent stimulus which causes substantial, but poorly understood, alterations in muscle tension. This study considered the involvement of endogenous mediators in cooling-induced tension changes in incubated guinea pig trachea. Smooth muscle tension was monitored in tracheal cylinders which were carefully cooled from 37 to 30 degrees C in the presence or absence of various inotropic mediators. In our study, cooling alone, at a rate of 1 degree C/min, was associated with an average loss of smooth muscle tension of 88.2 mg. Cooling tracheal tissue that had been previously exposed to 3 X 10(-6) M histamine, however, caused an additional increase in tracheal tension of 133 mg, over and above that caused by histamine alone. In the presence of 10(-5) M prostaglandin F2 alpha, or 10(-5) M thromboxane B2, cooling was associated with respective losses of smooth muscle tension of 211.4 and 211.2 mg, as compared to the tension associated with these mediators when they were used alone under control conditions. When the speed of tracheal cooling was increased to 40 degrees C/min, there was a slight increase in tension for 20 sec followed by a pronounced and sustained relaxation. The mechanisms involved in the response of airway smooth muscle to cooling are complex. The results of our study, however, suggest that mediators may play a role in the cooling-induced alterations of airway smooth muscle tension.     

Host-induced silencing of Mi-msp-1 confers resistance to root-knot nematode Meloidogyne incognita in eggplant

RNA interference (RNAi)-based host-induced gene silencing (HIGS) is emerging as a novel, efficient and target-specific tool to combat phytonematode infection in crop plants. Mi-msp-1, an effector gene expressed in the subventral pharyngeal gland cells of Meloidogyne incognita plays an important role in the parasitic process. Mi-msp-1 effector is conserved in few of the species of root-knot nematodes (RKNs) and does not share considerable homology with the other phytonematodes, thereby making it a suitable target for HIGS with minimal off-target effects. Six putative eggplant transformants harbouring a single copy RNAi transgene of Mi-msp-1 was generated. Stable expression of the transgene was detected in T₁, T₂ and T₃ transgenic lines for which a detrimental effect on RKN penetration, development and reproduction was documented upon challenge infection with nematode juveniles. The post-parasitic nematode stages extracted from the transgenic plants showed long-term RNAi effect in terms of targeted downregulation of Mi-msp-1. These findings suggest that HIGS of Mi-msp-1 enhances nematode resistance in eggplant and protect the plant against RKN parasitism at very early stage.

     

Induction and submerged cultivation of Valeriana jatamansi adventitious root cultures for production of valerenic acids and its derivatives

Plant Cell, Tissue and Organ Culture (PCTOC) - In vitro adventitious roots were induced from leaves of Valeriana jatamansi to assess their potential as a sustainable alternative to extract...     

Genome mining revealed polyhydroxybutyrate biosynthesis by Ramlibacter agri sp. nov., isolated from agriculture soil in Korea

A white-colony-forming, facultative anaerobic, motile and Gram-stain-negative bacterium, designated G-1-2-2 ^T was isolated from soil of agriculture field near Kyonggi University, Republic of Korea. Strain G-1-2-2 ^T synthesized the polyhydroxybutyrate and could grow at 10–35 °C. The phylogenetic analysis based on 16S rRNA gene sequence showed that, strain G-1-2-2 ^T formed a lineage within the family Comamonadaceae and clustered as a member of the genus Ramlibacter. The 16S rRNA gene sequence of strain G-1-2-2 ^T showed high sequence similarities with Ramlibacter ginsenosidimutans BXN5-27 ^T (97.9%), Ramlibacter monticola G-3-2 ^T (97.9%) and Ramlibacter alkalitolerans CJ661^T (97.5%). The sole respiratory quinone was ubiquinone-8 (Q-8). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and an unidentified phospholipid. The principal cellular fatty acids were C_16:0, cyclo-C_17:0, summed feature 3 (C_16:1ω7c and/or C_16:1ω6c) and summed feature 8 (C_18:1ω7c and/or C_18:1ω6c). The genome of strain G-1-2-2 ^T was 7,200,642 bp long with 13 contigs, 6,647 protein-coding genes, and DNA G?+?C content of 68.9%. The average nucleotide identity and in silico DNA–DNA hybridization values between strain G-1-2-2 ^T and close members were?≤?81.2 and 24.1%, respectively. The genome of strain G-1-2-2 ^T showed eight putative biosynthetic gene clusters responsible for various secondary metabolites. Genome mining revealed the presence of atoB, atoB2, phaS, phbB, phbC, and bhbD genes in the genome which are responsible for polyhydroxybutyrate biosynthesis. Based on these data, strain G-1-2-2 ^T represents a novel species in the genus Ramlibacter, for which the name Ramlibacter agri sp. nov. is proposed. The type strain is G-1-2-2 ^T (=?KACC 21616 ^T?=?NBRC 114389 ^T).