Major intrinsic proteins (MIPs) in plants: a complex gene family with major impacts on plant phenotype

The ubiquitous cell membrane proteins called aquaporins are now firmly established as channel proteins that control the specific transport of water molecules across cell membranes in all living organisms. The aquaporins are thus likely to be of fundamental significance to all facets of plant growth and development affected by plant–water relations. A majority of plant aquaporins have been found to share essential structural features with the human aquaporin and exhibit water-transporting ability in various functional assays, and some have been shown experimentally to be of critical importance to plant survival. Furthermore, substantial evidence is now available from a number of plant species that shows differential gene expression of aquaporins in response to abiotic stresses such as salinity, drought, or cold and clearly establishes the aquaporins as major players in the response of plants to conditions that affect water availability. This review summarizes the function and regulation of these genes to develop a greater understanding of the response of plants to water insufficiency, and particularly, to identify tolerant genotypes of major crop species including wheat and rice and plants that are important in agroforestry. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

DNA adducts in human placenta exposed to ambient environment and passive cigarette smoke during pregnancy

BACKGROUND: The risk of human diseases and abnormal development under the relatively reduced toxic environmental exposure conditions of passive cigarette smoke and urban pollution is emerging as significant. To assess the genotoxic potential of such exposure, we analyzed the DNA adducts of polynuclear aromatic hydrocarbons (PAH), a proven marker of genotoxicity, in human placental DNA samples of pregnancies monitored for passive cigarette smoke exposure. METHODS: Maternal exposure to active and passive cigarette smoke was evaluated by verbal disclosure and urinary nicotine and cotinine measurements. PAH-DNA adducts were assayed by ELISA using a polyclonal antibody against benzo[alpha]pyrene-diol-epoxide-DNA in placental DNA. Birth weights of infants were recorded in these monitored pregnancies. RESULTS: Urinary nicotine and cotinine values were reduced in the passive smoke-exposed group compared to smokers and similar to those in the nonsmoker ambient exposure group. PAH-DNA and nicotine/cotinine values were not correlated with birth weight of the infant. PAH-DNA adducts were present in approximately 25% of samples exposed to passive cigarette smoke and ambient environment. CONCLUSIONS: The study has revealed that a subpopulation of humans is predisposed to accumulating PAH adducts independent of high levels of PAH sources (e.g., maternal cigarette smoke exposure). Because DNA adducts promote genomic changes, it is likely that this subpopulation is susceptible to diverse changes in the genome that may influence human development.     

The FKBP families of higher plants: Exploring the structures and functions of protein interaction specialists

The FK506-binding proteins (FKBPs) are known both as the receptors for immunosuppressant drugs and as prolyl isomerase (PPIase) enzymes that catalyse rotation of prolyl bonds. FKBPs are characterised by the inclusion of at least one FK506-binding domain (FKBd), the receptor site for proline and the active site for PPIase catalysis. The FKBPs form large and diverse families in most organisms, with the largest FKBP families occurring in higher plants. Plant FKBPs are molecular chaperones that interact with specific protein partners to regulate a diversity of cellular processes. Recent studies have found that plant FKBPs operate in intricate and coordinated mechanisms for regulating stress response and development processes, and discoveries of new interaction partners expand their cellular influences to gene expression and photosynthetic adaptations. This review presents an examination of the molecular and structural features and functional roles of the higher plant FKBP family within the context of these recent findings, and discusses the significance of domain conservation and variation for the development of a diverse, versatile and complex chaperone family.     

Enhancement of Lipid Productivity in Oleaginous Colletotrichum Fungus through Genetic Transformation Using the Yeast CtDGAT2b Gene under Model-Optimized Growth Condition

Oleaginous fungi are of special interest among microorganisms for the production of lipid feedstocks as they can be cultured on a variety of substrates, particularly waste lingocellulosic materials, and few fungal strains are reported to accumulate inherently higher neutral lipid than bacteria or microalgae. Previously, we have characterized an endophytic filamentous fungus Colletotrichum sp. DM06 that can produce total lipid ranging from 34% to 49% of its dry cell weight (DCW) upon growing with various carbon sources and nutrient-stress conditions. In the present study, we report on the genetic transformation of this fungal strain with the CtDGAT2b gene, which encodes for a catalytically efficient isozyme of type-2 diacylglycerol acyltransferase (DGAT) from oleaginous yeast Candida troplicalis SY005. Besides the increase in size of lipid bodies, total lipid titer by the transformed Colletotrichum (lipid content ∼73% DCW) was found to be ∼1.7-fold more than the wild type (lipid content ∼38% DCW) due to functional activity of the CtDGAT2b transgene when grown under standard condition of growth without imposition of any nutrient-stress. Analysis of lipid fractionation revealed that the neutral lipid titer in transformants increased up to 1.8-, 1.6- and 1.5-fold compared to the wild type when grown under standard, nitrogen stress and phosphorus stress conditions, respectively. Lipid titer of transformed cells was further increased to 1.7-fold following model-based optimization of culture conditions. Taken together, ∼2.9-fold higher lipid titer was achieved in Colletotrichum fungus due to overexpression of a rate-limiting crucial enzyme of lipid biosynthesis coupled with prediction-based bioprocess optimization.     

Length–weight relationships of four indigenous fish species from Brahmaputra River,Assam, India

The present study was undertaken with the objective to estimate the length‐weight Relationships (LWRs) for four species collected from the Brahmaputra River, Assam, India. The fish samples were collected quarterly from different sampling sites using gill net (mesh size ranges 1–1.5 cm, locally called Mola lungi jal), cast net (mesh size ranges 1.0–2.0 cm, locally called Kevalijal) and triangular dip nets (mesh size ranges 0.75–1.25 cm locally called khorajal) during the time period between May, 2016 to April, 2018 (2 years). The b value of the LWR ranged from 3.028 (for Parambasis lala) to 3.196 (for Psilorynchus balitora). In this study the relationship between length‐weight were highly correlated (p < 0.05).     

Pseudohalide supported mononuclear trans-Ni complexes of cationic and neutral dinitrogen heterocycles

Two mixed ligand complexes trans-[Ni(NCS)₄(PpzH)₂] (1) and trans-[Ni(NCO)₂(Imd)₄] (2) (where Ppz = piperazine; Imd = imidazole) were synthesized from one-pot reactions, and their crystal and molecular structures were determined. The reaction of NiCl₂·4H₂O with piperazine and KSCN in a 1:2:4 mole ratio in aqueous MeOH at room temperature under stirring condition affords 1. Whereas the reaction of NiCl₂·6H₂O with imidazole and NaOCN in a 1:4:2 mole ratio in aqueous MeOH at room temperature under stirring condition yields 2 quantitatively. The nickel ions are hexacoordinated by six nitrogen donor atoms of two different origin, thiocyanate and piperazinium ions in case of 1 and cyanate ion and neutral imidazole in case of 2, to form tetragonally elongated and quite regular octahedral arrangements. In 1, the average Ni-N_ppz distance is 2.198 Å is longer than the average Ni-N_thc distance at 2.070 Å, whereas, in case of 2, the average Ni-N_imd distance at 2.112 Å and is close to the average Ni-N_cyt distance at 2.107 Å. The reactions in other varying stoichiometries failed to provide the hitherto unknown complexes [Ni(NCS)₂(Ppz)₄] and [Ni(NCO)₄(ImdH)₂] confirming the ease of protonation on non-bonding of piperazine is more compared to that of imidazole.     

EB virus-encoded RNAs are recognized by RIG-I and activate signaling to induce type I IFN

Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) are nonpolyadenylated, untranslated RNAs, exist most abundantly in latently EBV-infected cells, and are expected to show secondary structures with many short stem-loops. Retinoic acid-inducible gene I (RIG-I) is a cytosolic protein that detects viral double-stranded RNA (dsRNA) inside the cell and initiates signaling pathways leading to the induction of protective cellular genes, including type I interferons (IFNs). We investigated whether EBERs were recognized by RIG-I as dsRNA. Transfection of RIG-I plasmid induced IFNs and IFN-stimulated genes (ISGs) in EBV-positive Burkitt's lymphoma (BL) cells, but not in their EBV-negative counterparts or EBER-knockout EBV-infected BL cells. Transfection of EBER plasmid or in vitro-synthesized EBERs induced expression of type I IFNs and ISGs in RIG-I-expressing, EBV-negative BL cells, but not in RIG-I-minus counterparts. EBERs activated RIG-I's substrates, NF-kappaB and IFN regulatory factor 3, which were necessary for type I IFN activation. It was also shown that EBERs co-precipitated with RIG-I. These results indicate that EBERs are recognized by RIG-I and activate signaling to induce type I IFN in EBV-infected cells.     

Long-term Exposure of Variable Dietary Protein-to-Carbohydrate Ratio: Effect on Brain Regional Glutamatergic Activity with Age

Glutamatergic activity of hypothalamus and hippocampus of young (3 months) male albino rats having normal diet [protein (20%)–carbohydrate (68%)] was increased with the increase of age. Long-term (60 consecutive days) feeding of low protein (8%)–high carbohydrate (80%) diet (LP–HC) increased glutamatergic activity in these brain regions of young rats and decreased that in aged (18 months). On the contrary, supplementation of high protein (50%)–low carbohydrate (38%) diet (HP–LC) under similar condition decreased glutamatergic activity in those brain regions of young and increased that in aged brain regions. Thus, prolonged exposure of LP–HC diet may damage young brain; whereas, HP–LC diet under similar condition causes excitotoxicity to aged brain. Therefore, considering the present scenario in relation to metabolism and receptor activity of glutamatergic system, it may be suggested that long-term consumption of LP–HC and HP–LC diets modulate the brain regional glutamatergic activity reversibly with age.     

2,2′-Diphenyl-3,3′-Diindolylmethane: A Potent Compound Induces Apoptosis in Breast Cancer Cells by Inhibiting EGFR Pathway

Despite recent advances in medicine, 30–40% of patients with breast cancer show recurrence underscoring the need for improved effective therapy. In this study, by in vitro screening we have selected a novel synthetic indole derivative 2,2''-diphenyl-3,3''-diindolylmethane (DPDIM) as a potential anti- breast cancer agent. DPDIM induces apoptosis both in vitro in breast cancer cells MCF7, MDA-MB 231 and MDA-MB 468 and in vivo in 7,12-dimethylbenz[α]anthracene (DMBA) induced Sprague-Dawley (SD) rat mammary tumor. Our in vitro studies show that DPDIM exerts apoptotic effect by negatively regulating the activity of EGFR and its downstream molecules like STAT3, AKT and ERK1/2 which are involved in the proliferation and survival of these cancer cells. In silico predictions also suggest that DPDIM may bind to EGFR at its ATP binding site. DPDIM furthermore inhibits EGF induced increased cell viability. We have also shown decreased expression of pro-survival factor Bcl-XL as well as increase in the level of pro-apoptotic proteins like Bax, Bad, Bim in DPDIM treated cells in vitro and in vivo. Our results further indicate that the DPDIM induced apoptosis is mediated through mitochondrial apoptotic pathway involving the caspase-cascade. To the best of our knowledge this is the first report of DPDIM for its anticancer activity. Altogether this report suggests that DPDIM could be an effective therapeutic agent for breast cancer.