Improving micropropagation of Mentha × piperita L. using a liquid culture system

In the current study, in vitro shoot proliferation and plant regeneration of Mentha × piperita L. (peppermint) cultivar ‘Black Mitcham’ was compared in semi-solid and liquid culture systems. Shoot tips from field-grown plants were used as explants to study shoot proliferation response on either Murashige and Skoog (MS) or Chee and Pool (C2D) medium containing varying levels of 6-benzylaminopurine (BAP), kinetin, and 6-γ,γ-dimethylallyl aminopurine (2iP). Differences in leaf ultrastructure and antioxidant capacity of greenhouse-grown and micropropagation-derived plants were studied to identify potential changes occurring during in vitro culture. Among the various media treatments tested, the maximum number of shoots was produced on the C2D medium with 4.0 μM BAP (40.7) followed by the MS medium with 4.0 μM BAP (32.2). Among the rooting treatments, shoots on the MS medium with 1.0 μM indole-3-butyric acid (IBA) produced the maximum number of roots (14.4). The number of shoots produced in Liquid Lab Rocker® (LLR) vessels containing liquid C2D medium with BAP (103.4) was significantly higher than that produced on semi-solid medium (40.7). No differences were observed in the leaf ultrastructure and antioxidant capacity of leaf extracts obtained from greenhouse-grown and micropropagation-derived plants. The study indicates that the liquid culture system under the described conditions can enhance peppermint micropropagation, with plant material being potentially valuable for use in herbal supplements and essential oil production.

     

Correction to: Improving micropropagation of Mentha × piperita L. using a liquid culture system

In Vitro Cellular & Developmental Biology - Plant - This correction reflects Sadanand A. Dhekney’s updated e-mail address and affiliation.     

Endothelial Cells Provide a Notch-Dependent Pro-Tumoral Niche for Enhancing Breast Cancer Survival,Stemness and Pro-Metastatic Properties

Treating metastasis has been challenging due to tumors complexity and heterogeneity. This complexity is partly related to the crosstalk between tumor and its microenvironment. Endothelial cells -the building blocks of tumor vasculature- have been shown to have additional roles in cancer progression than angiogenesis and supplying oxygen and nutrients. Here, we show an alternative role for endothelial cells in supporting breast cancer growth and spreading independent of their vascular functions. Using endothelial cells and breast cancer cell lines MDA-MB231 and MCF-7, we developed co-culture systems to study the influence of tumor endothelium on breast tumor development by both in vitro and in vivo approaches. Our results demonstrated that endothelial cells conferred survival advantage to tumor cells under complete starvation and enriched the CD44^HighCD24^Low/- stem cell population in tumor cells. Moreover, endothelial cells enhanced the pro-metastatic potential of breast cancer cells. The in vitro and in vivo results concordantly confirmed a role for endothelial Jagged1 to promote breast tumor through notch activation. Here, we propose a role for endothelial cells in enhancing breast cancer progression, stemness, and pro-metastatic traits through a perfusion-independent manner. Our findings may be beneficial in developing novel therapeutic approaches.     

The impact of illicit drug use on spontaneous hepatitis C clearance: experience from a large cohort population study

Background and Aims

Acute hepatitis C infection usually ends in chronic infection, while in a minority of patients it is spontaneously cleared. The current population-based study is performed on a large cohort in Golestan province of Iran to examine the demographic correlates of Spontaneous Hepatitis C Clearance.

Methods

Serum samples used in this study had been stored in biorepository of Golestan Cohort Study. These samples were evaluated for anti hepatitis C Virus by third generation Enzyme-linked immunosorbent assay (ELISA). Subjects who tested positive were then invited and tested by Recombinant Immunoblot Assay (RIBA) and Ribonucleic Acid Polymerase Chain Reaction test (PCR). If tested positive for RIBA, subjects were recalled and the two tests were re-done after 6 months. Those subjects who again tested positive for RIBA but negative for PCR were marked as cases of spontaneous clearance.

Results

49,338 serum samples were evaluated. The prevalence of Chronic Hepatitis C Virus (CHCV) infection based on PCR results was 0.31%. Among those who had acquired hepatitis C, the rate of SC was 38%. In multivariate analysis, illicit drug use both Injecting Use (OR = 3.271, 95% CI: 1.784–6.000, p-value<0.001) and Non-Injecting Use (OR = 1.901, 95% CI: 1.068–3.386, p-value = 0.029) were significant correlates of CHCV infection versus SC.

Conclusions

Illicit drug use whether intravenous or non-intravenous is the only significant correlate of CHCV, for which several underlying mechanisms can be postulated including repeated contacts with hepatitis C antigen.     

Tolerance of pesticides and antibiotic resistance in bacteria isolated from wastewater-irrigated soil

A total of 64 bacterial isolates (40 Pseudomonas spp., 12 Azotobacter and 12 Rhizobium spp.) were characterized on the basis of morphological, cultural and biochemical characteristics. All the isolates were tested for their tolerance to the pesticides endosulfan, carbofuran, and malathion. 12.5% of the Pseudomonas isolates from soil tolerated concentrations of 1600 g malathion ml whereas 7.5% of isolates tolerated the same concentration of carbofuran. However, Pseudomonas isolates demonstrated a tolerance limit to endosulfan at a concentration of 800 g/ml. Asymbiotic N₂-fixers (Azotobacter) and symbiotic N₂-fixers (Rhizobium spp.) were also able to tolerate concentrations of pesticides up to 1600 g/ml. All the isolates were further tested for their antibiotic susceptibility against seven different antibiotics, nalidixic acid, cloxacillin, chloramphenicol, tetracycline, amoxycillin, methicillin, doxycycline. 100% of the Pseudomonas isolates were resistant to cloxacillin and 57.5% were resistant to methicillin. 7.5% of the isolates exhibited multiple resistance to five different antibiotics in three different combinations whereas 25% of the isolates showed multiple resistance to four different antibiotics in seven different combinations. Some of the resistant isolates were also screened for plasmid DNA and found to harbour a single plasmid.     

Theileria highjacks JNK2 into a complex with the macroschizont GPI (GlycosylPhosphatidylInositol)‐anchored surface protein p104

Constitutive c‐Jun N‐terminal kinase (JNK) activity characterizes bovine T and B cells infected with Theileria parva, and B cells and macrophages infected with Theileria annulata. Here, we show that T. annulata infection of macrophages manipulates JNK activation by recruiting JNK2 and not JNK1 to the parasite surface, whereas JNK1 is found predominantly in the host cell nucleus. At the parasite's surface, JNK2 forms a complex with p104, a GPI‐(GlycosylPhosphatidylInositol)‐anchor T. annulata plasma membrane protein. Sequestration of JNK2 depended on Protein Kinase‐A (PKA)‐mediated phosphorylation of a JNK‐binding motif common to T. parva and a cell penetrating peptide harbouring the conserved p104 JNK‐binding motif competitively ablated binding, whereupon liberated JNK2 became ubiquitinated and degraded. Cytosolic sequestration of JNK2 suppressed small mitochondrial ARF‐mediated autophagy, whereas it sustained nuclear JNK1 levels, c‐Jun phosphorylation, and matrigel traversal. Therefore, T. annulata sequestration of JNK2 contributes to both survival and dissemination of Theileria‐transformed macrophages.     

Peptide selected by phage display increases survival of SH-SY5Y neurons comparable to brain-derived neurotrophic factor

Brain-derived neurotrophic factor (BDNF) is a well-known neuroprotectant and a potent therapeutic candidate for neurodegenerative diseases. However, there are several clinical concerns about its therapeutic applications. In the current study, we designed and developed BDNF-mimicking small peptides as an alternative to circumvent these problems. A phage-displayed peptide library was screened using BDNF receptor (neurotrophic tyrosine kinase receptor type2 [NTRK2]) and evaluated by ELISA. The peptide sequences showed similarity to loop2 of BDNF, they were recognized as discontinuous epitopes though. Interestingly, in silico molecular docking showed strong interactions between the peptide three-dimensional models and the surface residues of the NTRK2 protein at the IgC2 domain. A consensus peptide sequence was then synthesized to generate a mimetic construct (named as RNYK). The affinity binding and function of this construct was confirmed by testing against the native structure of NTRK2 in SH-SY5Y cells in vitro using flow-cytometry and MTT assays, respectively. RNYK at 5 ng/mL prevented neuronal degeneration of all- trans-retinoic acid-treated SH-SY5Y with equal efficacy to or even better than BDNF at 50 ng/mL.