Seasonal changes in stem diameter and leaf development in a tropical montane forest

Abstract. Seasonal patterns of stem diameter changes in evergreen and deciduous species of a tropical montane forest in the Central Himalayas (300–2250 m a.s.l.) were investigated in relation to leaf development. Ca. 75 % of the annual rainfall in this region occurs in a short period, from mid-June to mid-September and the remaining months are dry. It was assumed that changes in stem diameter are correlated with changes in water stress. Each evergreen species could be characterized by leaf longevity of about one year; each species showed pronounced summer leaf drop and simultaneous new leaf formation. Winter stem shrinkage was more pronounced in deciduous species than in evergreen ones. The deciduous species also showed a greater proportional loss of leaf mass (before abscission) than the evergreen species. Winter leaf fall in deciduous species was related to the pronounced stem shrinkage. The leaf fall enabled these species to control further water loss. Being more resistant to desiccation, the evergreen species retained their leaves throughout the winter but showed gradual loss of leaf mass, presumably in order to control water loss. In all species, leaf expansion was completed before the onset of the rainy season, when water stress was high. This strategy has definite advantages in a climate with a monsoon pattern of rainfall. Evergreen species, showing pronounced leaf drop in summer, have advantages over deciduous species; hence their preponderance in the region.     

Ecological niche modelling and population genetic analysis of Indian temperate bamboo Drepanostachyum falcatum in the western Himalayas

Journal of Plant Research - The present study was conducted to understand the key ecological and biological questions of conservation importance in Drepanostachyum falcatum which aimed to map...     

Difference in androgen-dependent change of non-histone proteins between dorsolateral and ventral prostates of rats

A novel species of non-histone protein having a molecular weight of approximately 20,000 (20K), abundantly localized in the dorsolateral prostate, was found to be decreased in the content by castration and to be restored by replacement of androgen, in addition to non-histone proteins of molecular weights ≥ 34,000. The content of $\text{20K}\text{DNA}$ was more rapidly decreased by castration, but more slowly restored by replacement of androgen, with the dorsolateral prostate than the ventral prostate. Of other nuclear proteins, non-histone proteins of molecular weights ≥ 90,000 in the dorsolateral prostate were more susceptible to the decrease by castration, whereas those of all kinds of histones were hardly dependent on the androgen level.     

Leaf growth pattern in evergreen and deciduous species of the Central Himalaya,India

Leaf growth patterns were investigated in 11 evergreen (with leaf life-spans of just more than 1 year) and 15 deciduous species, occurring along an elevational gradient of 600–2200 m elevation in the Central Himalaya. Records were made of the leaf initiation period, leaf population dynamics, leaf expansion, leaf mass changes, leaf longevity and related parameters. Species of both groups produced leaves at similar rates during March to April, the driest period of the year. Species of both groups had approximately fully developed foliage during the warm, wet period (mid-June to mid-September) of the monsoon. However, significant differences were found at group level in other characters: shoot length (19.5 cm per shoot for deciduous and 11.7 cm for evergreen species); leaf population per 10 cm shoot length (4.7 vs 15.0); leaf area (107.9 vs 41.4 cm²/ leaf); specific leaf mass (106.9 vs 191.3 g/m²); and leaf mass loss after the monsoon period, being rapid and higher (31.6%) in deciduous species and slow and limited in the evergreens (26.2%). However, species of the two groups showed considerable overlaps in the values of above characters. The evergreen species of the Central Himalaya resembled the deciduous species of the region more than the multi-year leaves of clearly evergreen species. The evergreens bear leaves throughout the year, but like deciduous species bear the cost of annual replacement of old leaves by new leaves. They seem to outcompete deciduous species by producing annually a greater mass of leaves of low-carbon cost (per unit leaf mass), which is capable of conducting photosynthesis all year round. A situation of less marked contrast between favourable and nonfavourable periods, with respect to temperature, seems to favour the leaf characters of the evergreens.     

Site-specific DNA cleavage by artificial zinc finger-type nuclease with cerium-binding peptide

The addition of a new function to native proteins is one of the most attractive protein-based designs. In this study, we have converted a C(2)H(2)-type zinc finger as a DNA-binding motif into a novel zinc finger-type nuclease by connecting two distinct zinc finger proteins (Sp1 and GLI) with a functional linker possessing DNA cleavage activity. As a DNA cleavage domain, we chose an analogue of the metal-binding loop (12 amino acid residues), peptide P1, which has been reported to exhibit a strong binding affinity for a lanthanide ion and DNA cleavage ability in the presence of Ce(IV). Our newly designed nucleases, Sp1(P1)GLI and Sp1(P1G)GLI, can strongly bind to a lanthanide ion and show a unique DNA cleavage pattern, in which certain positions between the two DNA-binding sites are specifically cleaved. The present result provides useful information for expanding the design strategy for artificial nucleases.     

Plant-based anticancer molecules: a chemical and biological profile of some important leads

A number of natural products, with diverse chemical structures, have been isolated as anticancer agents. Several potential lead molecules such as camptothecin, vincristine, vinblastine, taxol, podophyllotoxin, combretastatins, etc. have been isolated from plants and many of them have been modified to yield better analogues for activity, toxicity or solubility. Several successful molecules like topotecan, irinotecan, taxotere, etoposide, teniposide, etc. also have emerged as drugs upon modification of these natural leads and many more are yet to come. In this review, the authors have focused on four important anticancer leads, that is, camptothecin, taxol, combretastatin A-4 and podophyllotoxin. Their chemistry, structure and activity relationships, biological activities, modes of action, analogue synthesis and future prospects have been discussed.     

Effect of trifluralin on growth, morphology, and nucleic Acid synthesis

Roots and shoots of corn seedlings (Zea mays L. var. Dixie 18) germinated in trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) solutions are characterized by radial enlargement of the cortical cells and by multinucleate cells in the meristematic regions. Trifluralin inhibits elongation of Avena coleoptile sections at concentrations of 0.1 μm to 10 μm. Synthesis of DNA, RNA, and protein is suppressed in the root tips while no significant effect is noticeable in the shoots of corn germinated in trifluralin. A ³²P time-course study of 48, 72, and 96 hours utilizing phenol extraction and MAK column separation of corn root and shoot nucleic acids showed suppression of ³²P incorporation in the treated roots; however, the 72 and 96 hour treated shoots incorporated a much greater amount than the control with most of the increased incorporation found in the sRNA and DNA fractions. The increased activity in the DNA may be due to a high G-C type DNA. No selective suppression or enhancement of any particular RNA species was noticed in the treated plants.     

Improvements in algal lipid production: a systems biology and gene editing approach

Background: In the wake of rising energy demands, microalgae have emerged as potential sources of sustainable and renewable carbon-neutral fuels, such as bio-hydrogen and bio-oil.

Purpose: For rational metabolic engineering, the elucidation of metabolic pathways in fine detail and their manipulation according to requirements is the key to exploiting the use of microalgae. Emergence of site-specific nucleases have revolutionized applied research leading to biotechnological gains. Genome engineering as well as modulation of the endogenous genome with high precision using CRISPR systems is being gradually employed in microalgal research. Further, to optimize and produce better algal platforms, use of systems biology network analysis and integration of omics data is required. This review discusses two important approaches: systems biology and gene editing strategies used on microalgal systems with a focus on biofuel production and sustainable solutions. It also emphasizes that the integration of such systems would contribute and compliment applied research on microalgae.

Conclusions: Recent advances in microalgae are discussed, including systems biology, gene editing approaches in lipid bio-synthesis, and antenna engineering. Lastly, it has been attempted here to showcase how CRISPR/Cas systems are a better editing tool than existing techniques that can be utilized for gene modulation and engineering during biofuel production.     

Pituitary gland of the exotic carp, Carassius carassius Linn., with reference to the histocytology of the adenohypophysis in conjunction to male and female rhythms of reproduction

The pituitaries of the exotic carp (Carassius carassius) are studied at the light microscopic level, for the characterization of the adenohypophysial cell-types with particular emphasis to the gonadotropic potency of the pituitary in relation to the annual reproductive patterns. The gland in the fish is of the cranioleptobasic type. Based on the classical staining methods and localization of the differential cell-types, the adenohypophysis of the fish can be subdivided into the rostral (RPD) and proximal (PPD) pars distalis and the pars intermedia (PI). The pars nervosa (PN) of the fish consists of the neurosecretory (NS) fibres which show varied accumulations of the NS material in concert with the seasonal reproductive cycle. The NS tract is constituted of AF--ve nucleus praeopticus and AF + ve nucleus lateralis tuberis. 2 tinctorially different cell-types, corresponding to corticotrops and lactotrops of other teleosts, are identifiable in the RPD of the present species. In the PPD, 3 cell-types can be distinguished with various granule-staining procedures: they represent somatotrops, thyrotrops, and gonadotrops. Further, 2 gonadotropic cells with apparently different staining properties are discernible. In the PI are dispersed besides a few agranular cells, islets of 2 kinds of cells separable with combined PAS-PbH technique. Seasonal changes in the gonadosomatic index and diameter of the testicular lobules and egg diameter as indices of gonadal maturation are found to be closely interwoven with the morphometric alterations in the basophilic cell area (BCA) chosen as criterion of gonadotropic potency of the PPD. The maximum BCA values are preceded with the time of greatest atresia of the eggs indicating the influence of the pituitary gonadotropins in the follicular resorption in the test fish.