Computer vision analysis of somatic embryos of sweet potato [Ipomoea batatas (L.) Lam.] for assessing their ability to convert to plants

Apical and axial shoot tips of sweet potato were cultured to produce somatic embryos that mature and develop into plants in basal nutrient medium. However, the lack of high regeneration efficiency is an impediment to the use of somatic embryos to produce synthetic seeds. Conversion experiments with mature embryos over a 20-day period revealed that 80–90% of the embryos formed roots but only 40–50% formed shoots. Using computer vision and canonical or Fisher discriminant function (CDA) analysis along with conversion results, it was possible to correctly classify competent embryos 40–50% of the time based on size features, 50–60% of the time based on shape features, and 55–60% of the time based on color features. Non-competent embryos were correctly classified 65–75%, 55–60%, and 70–75% of the time based on size, shape, and color, respectively. These results can be used effectively to identify and select competent embryos for improved regeneration efficiency. Received: 2 January 1997 / Revision received: 21 January 1998 / Accepted: 12 February 1998     

Effect of Nitrate on Bradyrhizobium — Mungbean (Vigna radiata) Symbiosis in presence of Syringaldehyde

Bradyrhizoblum — mungbean (Vigna radiata) symbiosis was influenced by the application of nitrate in combination with.yrlngaldehyde. Application of nitrate alone at lower concentrations (2, 5 mM) caused a reduction at initial stage (10 DAS) while at later stage (35 DAS–45 DAS) enhanced the nodulation status (nodule number, nodule weight) and nodule efficiency (acetylene reduction activity). Higher concentration of nitrate (10 mM) caused a reduction in nodule number, nodule weight and acetylene reduction activity. Syringaldehyde alone improved the nodulation status and nodule efficiency while it acted synergistically when applied in combination with nitrate. These effects were also reflected in the biomass of plants.     

Exploring the Chemical and Biological Potential of Jamun (Syzygium cumini (L.) Skeels) Leaves: A Comprehensive Review

Leaves of jamun collected as agro by-produce during the cultivation of jamun is traditionally used as ayurvedic medicine to treat diabetes, gall bladder stones and other ailments. Most of the beneficial effects of jamun leaves are associated with phytochemicals found in jamun leaves such as gallic acid, tannins, mallic acid, flavonoids, essential oils, jambolin, ellagic acid, jambosine, antimellin and betulinic acid. Jamun possess curative activities like anticancer, antidiabetic, antifertility, anti-inflammatory, antidiarrheal, antimicrobial, antinociceptive, antioxidant, antiradiation, chemotherapeutic, and gastroprotective. The main goal of this review article is to provide information on the nutritional content, phytochemical composition and health promoting properties of jamun leaves. The review of literature based on the phytochemical composition and health promoting benefits of the jamun leaves, suggests that leaves can be used as potential constituent in the formulation of pharmacological drugs. From the review literature it is found that clinical, in-vivo, in-vitro studies are still required to check the health promoting effects of jamun leaves extracts on humans.     

Ultrastructural studies on the placentae of streptozotocin induced maternal diabetes in the rat

Following induction of diabetes by a single injection of (IP) streptozotocin (STZ) to pregnant Wistar rats on days 2, 4 and 6 to 12 of gestation, fetuses and placentae were collected on day 20. The controls were either untreated or vehicle treated; alternatively following STZ injection, 2-6 IU of insulin was administered (sc) daily until term. The placentae were fixed in a glutaraldehyde and paraformaldehyde mixture and ultrathin sections were examined under the electron microscope. The structure of the vehicle treated control resembled that of the untreated control. The insulin control group had pathological changes similar to those of the diabetic group but with considerably less frequency. The giant cells in the basal zone of STZ group were numerous; they had abundant dilated cisternae of rough endoplasmic reticulum, intracytoplasmic fibrinoid and nuclear inclusions. The trophospongial cells presented numerous clear vacuoles, lysosomes and myelin bodies. Enlarged vacuoles often impinged deeply on the nucleus. The glycogen cells disintegrated resulting in cyst formation. In the labyrinthine zone, layer I trophoblast revealed increased number of large pores through which layer II trophoblast projected into the maternal sinusoid. Layer II had abundant glycogen, lipid droplets and lysosomes. Layer III had imbibed much fluid and appeared foamy with swollen organelles. Fibrinoid substance was produced by the giant cells, basophils and the trophoblast bordering the maternal sinusoids. Cyst development was preceded by degeneration of glycogen cells in the basal zone and of the trophoblast in the labyrinthine zone. Pronounced development of gonadotropin/somatotropin granule-like 'secretory granules' and smooth endoplasmic reticulum associated lipid droplets also characterised the labyrinthine trophoblast. The observed placental pathology appears to correlate well with the intrauterine growth retardation and fetal malformations recorded in this animal model.     

1H, 13C and 15N backbone and side chain resonance assignments of a Myxococcus xanthus anti-repressor with no known sequence homologues

The CarS antirepressor activates a photo-inducible promoter in Myxococcus xanthus by physically interacting with the CarA repressor and eliminating the latter’s binding to operator DNA. Interestingly, interactions with both CarS and operator are crucially dependent on the DNA recognition helix of the CarA winged-helix DNA-binding domain. The CarA–CarS and the CarA-operator interfaces therefore overlap, and CarS may have structural features that mimic operator DNA. CarS has no known sequence homologues and its Gly and Pro contents are unusually high. Here, we report ¹H, ¹³C and ¹⁵N backbone and side chain assignments of CarS1, an 86-residue truncated yet fully functional variant of CarS. Secondary structural elements inferred from these data differ from those predicted from sequence.     

Lacrimal Proline Rich 4 (LPRR4) Protein in the Tear Fluid Is a Potential Biomarker of Dry Eye Syndrome

Dry eye syndrome (DES) is a complex, multifactorial, immune-associated disorder of the tear and ocular surface. DES with a high prevalence world over needs identification of potential biomarkers so as to understand not only the disease mechanism but also to identify drug targets. In this study we looked for differentially expressed proteins in tear samples of DES to arrive at characteristic biomarkers. As part of a prospective case-control study, tear specimen were collected using Schirmer strips from 129 dry eye cases and 73 age matched controls. 2D electrophoresis (2DE) and Differential gel electrophoresis (DIGE) was done to identify differentially expressed proteins. One of the differentially expressed protein in DES is lacrimal proline rich 4 protein (LPRR4). LPRR4 protein expression was quantified by enzyme immune sorbent assay (ELISA). LPRR4 was down regulated significantly in all types of dry eye cases, correlating with the disease severity as measured by clinical investigations. Further characterization of the protein is required to assess its therapeutic potential in DES.     

Reproductive characterization and preliminary studies on controlled breeding of Annatto (Bixa orellana L.)

Annatto (Bixa orellana L.) is an important dye-yielding medium-sized tree occurring in the tropics. Investigations aimed at elucidating the reproductive characters as well as establishing a set of breeding parameters for genetic improvement of B. orellana was carried out. Records on pollen/ovule ratios of annatto showed that this species is xenogamous. The acetolyzed pollen of B. orellana was tricolporate. The fluorochromatic test showed 95% pollen viability. The viability of the pollen grains decreased sharply after 4 h from anther dehiscence. The optimum time range for artificial pollination was standardized between 12:00 and 13:00 h. A high in vitro germination rate (92%) of freshly collected pollen was recorded in modified Brewbaker’s medium with 15% sucrose. Resource allocation studies showed that the construction of each flower cost 1.162 g. The floral vegetative cost was 75%. Of the total allocation, 21% was spent by the stamens. Based on identified reproductive characters, controlled pollination experiments were conducted by selecting four morphologically distinct parent plants: (1) green-fruited with reddish spines, (2) red-fruited, (3) brown large-fruited, and (4) with brown distorted fruits. In artificial cross-pollination experiments, wide variation ranges in fruit set (0–95%) and fruit maturation (0–85%) were observed in different crosses. The number of seeds per capsule also showed variation (0–40 per capsule). Germination studies of seeds raised from different crosses showed a maximum 93% germination. The present study proved that improvement in B. orellana could be achieved by adopting breeding techniques using specifically selected parents.     

An invasive Mimosa in India does not adopt the symbionts of its native relatives

Background and Aims

The large monophyletic genus Mimosa comprises approx. 500 species, most of which are native to the New World, with Central Brazil being the main centre of radiation. All Brazilian Mimosa spp. so far examined are nodulated by rhizobia in the betaproteobacterial genus Burkholderia. Approximately 10 Mya, transoceanic dispersal resulted in the Indian subcontinent hosting up to six endemic Mimosa spp. The nodulation ability and rhizobial symbionts of two of these, M. hamata and M. himalayana, both from north-west India, are here examined, and compared with those of M. pudica, an invasive species.

Methods

Nodules were collected from several locations, and examined by light and electron microscopy. Rhizobia isolated from them were characterized in terms of their abilities to nodulate the three Mimosa hosts. The molecular phylogenetic relationships of the rhizobia were determined by analysis of 16S rRNA, nifH and nodA gene sequences.

Key Results

Both native Indian Mimosa spp. nodulated effectively in their respective rhizosphere soils. Based on 16S rRNA, nifH and nodA sequences, their symbionts were identified as belonging to the alphaproteobacterial genus Ensifer, and were closest to the ‘Old World’ Ensifer saheli, E. kostiensis and E. arboris. In contrast, the invasive M. pudica was predominantly nodulated by Betaproteobacteria in the genera Cupriavidus and Burkholderia. All rhizobial strains tested effectively nodulated their original hosts, but the symbionts of the native species could not nodulate M. pudica.

Conclusions

The native Mimosa spp. in India are not nodulated by the Burkholderia symbionts of their South American relatives, but by a unique group of alpha-rhizobial microsymbionts that are closely related to the ‘local’ Old World Ensifer symbionts of other mimosoid legumes in north-west India. They appear not to share symbionts with the invasive M. pudica, symbionts of which are mostly beta-rhizobial.