Persistent organic pollutants in Pakistan: Potential threat to ecological integrities in terms of genotoxicity and oxidative stress

As a consequence of both increasing population and industrialization in agro-economic sector, Pakistan has inevitably been confronted by multicomplex environmental challenges. Owing in part to poor regulatory framework, pollution due to persistent organic pollutants (POPs) has caused serious problems throughout the country. Resultantly, extensive use of POPs is causing vigorous deterioration of environment and human health. The current study addresses: (1) the general information on associated ecological effects and toxicity assessment by meta-analysis for local fauna and flora (2) their respective occurrence in living organisms; and (3) sources and distribution patterns of various POPs classes in environmental compartments of Pakistan. Based on the study, it can be concluded that the environment of Pakistan is highly contaminated with organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), and polychlorinated naphthalenes (PCNs), which is further supported with the meta-analysis. Nevertheless, unavailability of environmental quality standards and food safety for POPs render it a forthcoming challenge of multicompartment toxicity exposure. Therefore, strategies must be planned for risk assessment of biologically active POPs, while the POP waste inventory should be elevated, along with the necessary measures to promote appropriate handling and treatment of POP as a matter of prime importance.     

Structural insights into FRS2α PTB domain recognition by neurotrophin receptor TrkB

The fibroblast growth factor receptor (FGFR) substrate 2 (FRS2) family proteins function as scaffolding adapters for receptor tyrosine kinases (RTKs). The FRS2α proteins interact with RTKs through the phosphotyrosine‐binding (PTB) domain and transfer signals from the activated receptors to downstream effector proteins. Here, we report the nuclear magnetic resonance structure of the FRS2α PTB domain bound to phosphorylated TrkB. The structure reveals that the FRS2α‐PTB domain is comprised of two distinct but adjacent pockets for its mutually exclusive interaction with either nonphosphorylated juxtamembrane region of the FGFR, or tyrosine phosphorylated peptides TrkA and TrkB. The new structural insights suggest rational design of selective small molecules through targeting of the two conjunct pockets in the FRS2α PTB domain. Proteins 2014; 82:1534–1541. © 2014 Wiley Periodicals, Inc.     

Life forms,leaf size spectra,regeneration capacity and diversity of plant species grown in the Thandiani forests,district Abbottabad,Khyber Pakhtunkhwa,Pakistan

The life form and leaf size spectra of plant species of the Thandiani forests, district Abbottabad, were studied during the summer of 2013. These forests host 252 plant species of 97 families. Biological spectra showed that Hemicryptophytes (80 spp., 31.74%) were dominant followed by Megaphanerophytes (51 spp., 20.24%), Therophytes (49 spp., 19.44%) and Nanophanerophytes (45 spp., 17.86). Hemicryptophytes are the indicators of cold temperate vegetation. At the lower elevations, Megaphanerophytes and Nanophanerophytes were dominant which confirm trees as dominant habit form due to high soil depth, moisture and temperature factors. Data on Leaf spectra in the area showed that Microphyllous (88 spp., 34.92%) species were dominant followed by Leptophyllous (74 spp., 29.36%) and Nanophyllous (60 spp., 23.80%). The Microphyllous plants again are the indicator of cold temperate zone as the area is situated at an elevation of 1191–2626 m. Similarly, Nanophylls were dominant at lower elevations. Data on family importance values and diversity among various communities were also recorded. Life form and Leaf spectra studies could be used to understand the micro climatic variation of the region.     

Experiences with the Mass Distribution of LPG Stoves in Rural Communities of Ghana

Household air pollution (HAP) is a leading cause of morbidity and mortality worldwide. To limit HAP exposure and environmental degradation from biomass fuel use, the Government of Ghana promotes liquefied petroleum gas (LPG) use in rural Ghana via the Rural LPG program (RLP). We assessed the experiences of the RLP in 2015, 2 years after its launch. A mixed methods approach was used involving Focus Group Discussions (19) and in-depth interviews (25). In addition, a survey questionnaire was administered to elicit socio-demographic characteristics, household cooking practices and stove use patterns of 200 randomly selected respondents. At about 9 months after LPG acquisition,?<?5% of LPG beneficiaries used their stoves. Some of the reasons ascribed to the low usage of the LPG cookstoves were financial constraints, distance to LPG filling point and fear of burns. Community members appreciate the convenience of using LPG. Our results underscore a need for innovative funding mechanisms contextualized within an overall economic empowerment of rural folks to encourage sustained LPG use. It emphasizes the need for innovative accessibility interventions. This could include establishing new LPG filling stations in RLP beneficiary districts to overcome the barriers to sustained LPG use.     

Lineage-restricted neural precursors can be isolated from both the mouse neural tube and cultured ES cells.

We have previously identified multipotent neuroepithelial (NEP) stem cells and lineage-restricted, self-renewing precursor cells termed NRPs (neuron-restricted precursors) and GRPs (glial-restricted precursors) present in the developing rat spinal cord (A. Kalyani, K. Hobson, and M. S. Rao, 1997, Dev. Biol. 186, 202-223; M. S. Rao and M. Mayer-Proschel, 1997, Dev. Biol. 188, 48-63; M. Mayer-Proschel, A. J. Kalyani, T. Mujtaba, and M. S. Rao, 1997, Neuron 19, 773-785). We now show that cells identical to rat NEPs, NRPs, and GRPs are present in mouse neural tubes and that immunoselection against cell surface markers E-NCAM and A2B5 can be used to isolate NRPs and GRPs, respectively. Restricted precursors similar to NRPs and GRPs can also be isolated from mouse embryonic stem cells (ES cells). ES cell-derived NRPs are E-NCAM immunoreactive, undergo self-renewal in defined medium, and differentiate into multiple neuronal phenotypes in mass culture. ES cells also generate A2B5-immunoreactive cells that are similar to E9 NEP-cell-derived GRPs and can differentiate into oligodendrocytes and astrocytes. Thus, lineage restricted precursors can be generated in vitro from cultured ES cells and these restricted precursors resemble those derived from mouse neural tubes. These results demonstrate the utility of using ES cells as a source of late embryonic precursor cells.     

Post-exposure temperature influence on the toxicity of conventional and new chemistry insecticides to green lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

Chrysoperla carnea (Stephens) is an important biological control agent currently being used in many integrated pest management (IPM) programs to control insect pests. The effect of post-treatment temperature on insecticide toxicity of a spinosyn (spinosad), pyrethroid (lambda cyhalothrin), organophosphate (chlorpyrifos) and new chemistry (acetamiprid) to C. carnea larvae was investigated under laboratory conditions. Temperature coefficients of each insecticide tested were evaluated. From 20 to 40 °C, toxicity of lambda cyhalothrin and spinosad decreased by 2.15- and 1.87-fold while toxicity of acetamiprid and chlorpyrifos increased by 2.00 and 1.79-fold, respectively. The study demonstrates that pesticide effectiveness may vary according to environmental conditions. In cropping systems where multiple insecticide products are used, attention should be given to temperature variation as a key factor in making pest management strategies safer for biological control agents. Insecticides with a negative temperature coefficient may play a constructive role to conserve C. carnea populations.     

The study of gene GJB2/DFNB1 causing deafness in humans by linkage analysis from district Peshawar

Families with at least 2 or more individuals having hereditary hearing loss were enrolled from different areas of Khyber Pakhtoonkhwa, mainly from district Peshawar. Detailed history was taken from each family to minimize the presence of other abnormalities and environmental causes for deafness. Families were questioned about skin pigmentation, hair pigmentation, and problems relating to balance, vision, night blindness, thyroid, kidneys, heart, and infectious diseases like meningitis, antibiotic usage, injury, and typhoid. The pedigree structures were based upon interviews with multiple family members, and pedigrees of the enrolled families were drawn using Cyrillic program (version 2.1). All families showed recessive mode of inheritance. I studied 8 families of these 10. For linkage analyses, studies for DFNB1 locus, 3 STR markers (D13S175, D13S292, and D13S787) were genotyped using polyacrylamide gel electrophoresis (PAGE) and haplotypes were constructed to determined, linkage with DFNB1 locus. From a total of 8 families, a single family-10 showed linkage to DFNB1 locus.     

Copper-induced changes in the growth, oxidative metabolism, and saponin production in suspension culture roots of Panax ginseng in bioreactors

Roots of Panax ginseng exposed to various concentrations of Cu (0.0, 5, 10.0, 25.0, and 50.0 μM) accumulated high amounts of Cu in a concentration-dependent and duration-dependent manner. Roots treated with 50 μM Cu resulted in 52% and 89% growth inhibition after 20 and 40 days, respectively. Saponin synthesis was stimulated at a Cu concentration between 5 and 25 μM but decreased at 50 μM Cu. Malondialdehyde content (MDA), lipoxygenase activity (LOX), superoxide ion (O₂ ^•−) accumulation, and H₂O₂ content at 5 and 10 μM Cu-treated roots were not increased but strongly increased at 50 μM Cu resulting in the oxidation of ascorbate (ASC) and glutathione (GSH) to dehydroascorbate (DHA) and glutathione disulfide (GSSG), respectively indicating a clear oxidative stress. Seven well-resolved bands of superoxide dismutase (SOD) were detected in the gel and an increase in SOD activity seemed to be mainly due to the induction of Fe-SOD 3. Five to 10 μM Cu slightly induced activity of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), guaiacol peroxidase (G-POD) but inhibited monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR) enzyme activities. No changes in catalase (CAT) activity and in activity gel were found up to 25 μM Cu, but both G-POD and CAT activities were inhibited at 50 μM Cu. Glutathione metabolism enzymes such as γ-glutamylcysteine synthetase (γ-GCS), glutathione-S-transferase (GST), and glutathione peroxidase activities (GPx) were activated at 5 and 10 μM Cu but were strongly inhibited at 50 μM Cu due to the Cu accumulation in root tissues. The strong depletion of GSH at 50 μM Cu was associated to the strong induction of γ-glutamyltranspeptidase (γ-GGT) activity. These results indicate that plant could grow under Cu stress (5–25 μM) by modulating the antioxidant defense mechanism for combating Cu induced oxidative stress.     

Prion protein gene polymorphisms in four goat breeds of Pakistan

Four different goat breeds (Pak-Angora, Dera Din Panah, Naachi and Teddy) of Pakistan were selected to investigate polymorphism in the prion protein gene (PrP gene) responsible for scrapie disease resistance in goats. Initially, genotyping of 187 animals of these four breeds by restriction fragment length polymorphism (RFLP) was done to see the genotype for codon 136 and 154. All the animals were monomorphic with a genotype of AARR except one animal of Teddy breed having the genotype of AARH. Sequencing of PrP gene of twenty animals representing these four goat breeds revealed two genotypes PPSSSS and PPSSPS with haplotypes PSS and PSP of PrP gene at the codon numbers 42, 138, and 240. All four breeds showed both wild type monomorphic sequence and mutant polymorphic sequences of these codons. The mutants of 42 and 138 codons translate the same amino acids as with the wild type sequences, while the mutant of codon 240 is responsible for a different amino acid translation i.e., serine to proline. In short, this study provides preliminary information about alleles and genotypes of PrP gene in four goat breeds of Pakistan.     

Expression of EGF receptor and FGF receptor isoforms during neuroepithelial stem cell differentiation

To characterize the role of epidermal growth factor (EGF) and fibroblast growth factor (FGF) in regulating neuroepithelial stem cells differentiation, we have examined the expression of FGF, EGF, and their receptors by neuroepithelial (NEP) cells and their derivatives. Our results indicate that undifferentiated NEP cells express a subset of FGF receptor (FGFR) isoforms, but do not express platelet-derived growth factor receptors (PDGFRs) or epidermal growth factor receptor (EGFR). The FGFR pattern of expression by differentiated neuron and glial cells differs from that found on NEP stem cells. FGFR-4 is uniquely expressed on NEP cells, while FGFR-1 is expressed by both NEP cells and neurons, and FGFR-2 is down-regulated during neuronal differentiation. FGFRs present on astrocytes and oligodendrocytes also represent a subset of those present on NEP cells. Expression of FGF and EGF by NEP cells and their progeny was also examined. NEP cells synthesize detectable levels of both FGF-1 and FGF-2, and EGF. FGF-1 and FGF-2 synthesis is likely to be biologically relevant, as cells grown at high density do not require exogenous FGF for their survival and cells grown in the presence of neutralizing antibodies to FGF show a reduction in cell survival and division. Thus, neuroepithelial cells synthesize and respond to FGF, but not to EGF, and are therefore distinct from other neural stem cells (neurospheres). The unique pattern of expression of FGF isoforms may serve to distinguish NEP cells from their more differentiated progeny.