Dynamic secretion changes in the salt glands of the mangrove tree species Avicennia officinalis in response to a changing saline environment

The specialized salt glands on the epidermis of halophytic plants secrete excess salts from tissues by a mechanism that is poorly understood. We examined the salt glands as putative salt and water bi‐regulatory units that can respond swiftly to altering environmental cues. The tropical mangrove tree species (Avicennia officinalis) is able to grow under fluctuating salinities (0.7–50.0 dS m^?1) at intertidal zones, and its salt glands offer an excellent platform to investigate their dynamic responses under rapidly changing salinities. Utilizing a novel epidermal peel system, secretion profiles of hundreds of individual salt glands examined revealed that these glands could secrete when exposed to varying salinities. Notably, rhythmic fluctuations observed in secretion rates were reversibly inhibited by water channel (aquaporin) blocker, and two aquaporin genes (PIP and TIP) preferentially expressed in the salt gland cells were rapidly induced in response to increasing salt concentration. We propose that aquaporins are involved and contribute to the re‐absorption of water during salt removal in Avicennia officinalis salt glands. This constitutes an adaptive feature that contributes to salt balance of trees growing in saline environments where freshwater availability is limited.     

Differentiation Capacities of the Foreleg Imaginal Disc of Sarcophaga ruficornis Fabr (Diptera, Sarcophagidae): I. Fate Map

When an imaginal disc of a mature larva is implanted into a host larva of the same age, it undergoes metamorphosis with the host. On the basis of the results obtained from the transplanted whole disc and disc fragments, a fate map of the foreleg disc of Sarcophaga ruficornis has been constructed. The fate map of S. ruficornis presented by us is basically similar to that of Drosophila but anterior and posterior rows of bristles of femur, apical, preapical and one long bristle of tibia have been precisely localized.     

Genetic interaction and mapping studies on the leaflet development (lld) mutant in Pisum sativum

In Pisum sativum, the completely penetrant leaflet development (lld) mutation is known to sporadically abort pinnae suborgans in the unipinnate compound leaf. Here, the frequency and morphology of abortion was studied in each of the leaf suborgans in 36 genotypes and in presence of auxin and gibberellin, and their antagonists. Various lld genotypes were constructed by multifariously recombining lld with a coch homeotic stipule mutation and with af, ins, mare, mfp, tl and uni-tac leaf morphology mutations. It was observed that the suborgans at all levels of pinna subdivisions underwent lld-led abortion events at different stages of development. As in leafblades, lld aborted the pinnae in leaf-like compound coch stipules. The lld mutation interacted with mfp synergistically and with other leaf mutations additively. The rod-shaped and trumpet-shaped aborted pea leaf suborgans mimicked the phenotype of aborted leaves in HD-ZIP-III-deficient Arabidopsis thaliana mutants. Suborganwise aborted morphologies in lld gnotypes were in agreement with basipetal differentiation of leaflets and acropetal differentiation in tendrils. Altogether, the observations suggested that LLD was the master regulator of pinna development. On the basis of molecular markers found linked to lld, its locus was positioned on the linkage group III of the P. sativum genetic map.     

An overview of the factors affecting sugar content of potatoes

Potatoes destined for making chips, French fries and other fried products, need to have low sugar content to avoid browning of the finished product. The sugar content of potatoes is determined by the genotype and several pre‐ and post‐harvest factors. The major pre‐harvest factors affecting sugar content are crop maturity, temperature during growth, mineral nutrition and irrigation, while important post‐harvest factors are mechanical stresses and storage conditions. Each genotype requires an ideal pre‐and post‐harvest treatment to maintain low sugar levels; any kind of stress results in sugar accumulations.     

Pluronic F-68 Stimulates Growth of Solanum dulcamara in Culture

The effects have been studied of the non-ionic surfactant, PluronicF-68, on the growth of transformed roots, callus and protoplastsof Solanum dulcamara L. Root growth was stimulated by additionof 0001–005% (w/v) of freshly-prepared, commercial gradePluronic to culture medium, with maximum increases in root freshand dry weights at 001%. Higher concentrations (05–10%w/v) of freshly-prepared Pluronic inhibited growth. A Pluronicfraction, prepared by passage through silica-Amberlite resin,retarded root growth even at concentrations that were stimulatorywith the commercial preparation. Similarly, commercial gradePluronic solutions stored at 4C or 22C for 5 d (‘aged’)also inhibited root growth. Roots grew faster on Pluronic F-68-treatedmembrane rafts compared with growth on commercially-availablerafts; such growth enhancement was comparable to that seen inmedium supplemented with 001% (w/v) freshly-prepared commercialPluronic. Callus growth was also stimulated by the addition of freshly-prepared,commercial grade Pluronic F-68 to medium, with maximum increasesat 01% (w/v); in contrast, 10% (w/v) Pluronic was inhibitoryto callus growth. The mean plating efficiency (15 d after plating)of protoplasts cultured at densities of 01–2010⁵ cm_–3was increased up to 26% by 01% (w/v) Pluronic, while 10% wasinhibitory. Both root and callus soluble carbohydrates and proteinswere increased by exposure to freshly-prepared, commercial Pluronic.Similarly, the specific activities of malate dehydrogenase andacid phosphatase were increased in Pluronic F-68-treated callusand roots. The biotechnological implications of these resultsare discussed in relation to the potential value of non-ionicsurfactants as growth-stimulating additives to plant culturemedia. Key words: Solanum dulcamara, Pluronic F-68, surfactant, transformed roots, callus, protoplasts, malate dehydrogenase, acid phosphatase     

Studies on the Water-Soluble Lens Proteins of the Lizard, Calotes versicolor III. Ontogenic Changes

Ontogeny of lens crystallins of the garden lizard, Calotes versicolor has been studied by gel filtration, polyacrylamide gel electrophoresis, 7M urea PAGE, SDS and 6M urea isoelectric focusing. Wet weight, diameter and the soluble protein content per lens were also determined as a function of age. The amount of α-crystallins increased slightly during development. The relative proportion of the putative δ-crystallins was significantly higher in the embryos than in the adult. The overall polypeptide pattern of crystallins changed markedly around the time of hatching.     

Frequent alterations of SLIT2–ROBO1–CDC42 signalling pathway in breast cancer: clinicopathological correlation

The aim of the study was to understand the role of SLIT2–ROBO1/2–CDC42 signalling pathways in development of breast cancer (BC). Primary BC samples (n=150), comprising of almost equal proportion of four subtypes were tested for molecular alterations of SLIT2, ROBO1, ROBO2 and CDC42, the key regulator genes of this pathway. Deletion and methylation frequencies of the candidate genes were seen in the following order: deletion, SLIT2 (38.6%) >ROBO1 (30%) >ROBO2 (7.3%); methylation, SLIT2 (63.3%) >ROBO1 (26.6%) >ROBO2 (9.3%). Majority (80%, 120/150) of the tumours showed alterations (deletion/methylation) in at least one of the candidate genes. Overall, alterations of the candidate genes were as follows: SLIT2, 75.3% (101/150); ROBO1, 45.3% (68/150); ROBO2, 15.3% (23/150). Significantly, higher alteration of SLIT2 locus was observed in triple negative breast cancer (TNBC) over HER2 subtype (P=0.0014). Similar trend is also seen in overall alterations of SLIT2 and/or ROBO1, in TNBC than HER2 subtype (P=0.0012); of SLIT2 and/or ROBO2 in TNBC than luminal A (P=0.014) and HER2 subtype (P=0.048). Immunohistochemical analysis of SLIT2, ROBO1/2 showed reduced expression, concordant with their molecular alterations. Also, high expression of total CDC42 (49/52; 94.2%) and reduced expression of phospho Serine-71 CDC42 (41/52; 78.8%) was observed. Coalterations of SLIT2 and/or ROBO1, SLIT2 and/or ROBO2 had significant association with reduced expression of phospho Serine-71 CDC42 (P=0.0012–0.0038). Alterations of SLIT2 and/or ROBO1, reduced expression of phospho Serine-71 CDC42 predicted poor survival of BC patients. Results indicate the importance of SLIT2–ROBO1–CDC42 signalling pathway in predicting tumour progression.