Novel (S)-1,3,4,12a-tetrahydropyrazino[2,1-c][1,4]benzodiazepine-6,12(2H,11H)-dione derivatives: Selective inhibition of MV-4-11 biphenotypic B myelomonocytic leukemia cells’ growth is accompanied by reactive oxygen species overproduction and apoptosis

A series of optically pure (R)- and (S)-1,3,4,12a-tetrahydropyrazino[2,1-c][1,4]benzodiazepine-6,12(2H,11H)-dione derivatives was designed and synthesized as novel anthramycin analogues in a three-step, one-pot procedure, and tested for their antiproliferative activity on nine following cell lines: MV-4-11, UMUC-3, MDA-MB-231, MCF7, LoVo, HT-29, A-549, A2780 and BALB/3T3. The key structural features responsible for exhibition of cytotoxic effect were determined: the (S)-configuration of chiral center and the presence of hydrophobic 4-biphenyl substituent in the side chain. Introduction of bromine atom into the 8 position (8g) or substitution of dilactam ring with benzyl group (8m) further improved the activity and selectivity of investigated compounds. Among others, compound 8g exhibited selective cytotoxic effect against MV-4-11 (IC₅₀?=?8.7?μM) and HT-29 (IC₅₀?=?17.8?μM) cell lines, while 8m showed noticeable anticancer activity against MV-4-11 (IC₅₀?=?10.8?μM) and LoVo (IC₅₀?=?11.0?μM) cell lines. The cell cycle arrest in G₁/S checkpoint and apoptosis associated with overproduction of reactive oxygen species was also observed for 8e and 8m.     

Solid-stemmed spring wheat cultivars give better androgenic response than hollow-stemmed cultivars in anther culture

Solid-stemmed spring wheat cultivars (Triticum aestivum L.) are resistant to the stem sawfly (Cephus cinctus Nort.) and lodging. Anthers of 24 spring wheat cultivars with varying content of pith in the stem were used in the experiment. All were classified into three groups: solid, medium–solid and hollow stems. There was considerable influence of the cultivar on callus formation and green plant regeneration. The highest efficiency of green plant regeneration (24%) was observed for the solid-stemmed AC Abbey cultivar. There was no regeneration from the explants of four cultivars: CLTR 7027, Alentejano, Marquis and Bombona. Principal component analysis showed no differences between the cases under observation (callus induction and green plant regeneration) in their response to pre-treatment temperatures (4 and 8°C). The examination of the effects of various auxin types in the induction medium on callus formation and green plant regeneration revealed that the strongest stimulation of these processes was observed in the C17 medium with 2,4-D and dicamba. The efficiency of callus formation and green plant regeneration was greater in solid-stemmed cultivars than in hollow-stemmed cultivars.     

Fine-Needle Aspiration Biopsy as a Preoperative Procedure in Patients with Malignancy in Solitary and Multiple Thyroid Nodules

Background

Fine-needle aspiration biopsy (FNAB) is a recognized technique for the basic, preoperative cytological diagnosis of thyroid nodules.

Aim of the Study

To analyze the accuracy of FNAB in the diagnosis of thyroid cancer in patients with solitary and multiple thyroid nodules and to compare the demographic, clinical and pathological characteristics of patients with thyroid carcinoma in solitary and multiple tumors.

Materials and Methods

The case records of 2,403 patients with solitary and multiple thyroid tumors treated consecutively between 2008 and 2013 were analyzed retrospectively. We selected 1,645 for further analysis. A solitary thyroid nodule was observed in 493 patients, and multiple nodules were detected in 1,152 patients. Further classification of the patients in these two groups was performed on the basis of the FNAB results, type of surgery performed and histopathology. TC was histopathologically confirmed in 166 patients, and benign disease was found in 1,479. The TC patients were assigned to the study group, and those with benign thyroid disease were placed into the control group. The study group was divided into two subgroups according to the presence of cancer in a single thyroid nodule or in multiple nodules. Malignancy in a solitary thyroid nodule was diagnosed in 98 (59.0%) patients, and cancer in multiple nodules was diagnosed in 68 (41.0%). Comparative analyses of the demographic, clinical and histopathological characteristics were performed for both subgroups. The following statistical analyses were performed: comparative characteristic of subgroups, ROC analysis for study group and subgroup of patients, and multivariable logistic regression analysis for study group.

Results

The rate of prediction of TC by FNAB was three times higher in the patients with a solitary thyroid nodule compared with those with multiple thyroid nodules and it was statistically significant (p<0.001). The rate of total thyroid resection and lack of necessity for reoperation were also significantly higher in the TC patients with a solitary nodule. The histopathological results showed that significantly more patients with a solitary nodule had advanced-stage TC (stage III or IV) and tumor progression (pT3 or pT4) (p = 0.002 for both). ROC analysis demonstrated that the overall accuracy of FNAB as a predictor of thyroid cancer presence was high, especially for the subgroup of patients with a solitary thyroid nodule (AUC = 0.958, p<0.0001). Multivariable logistic regression analysis confirmed that a positive FNAB result was the sole predictor of the performance of total resection in the TC study group (p<0.0001), while a negative FNAB result and the presence of a papillary cancer type were independent predictors of the risk of reoperation (p<0.0001 and p = 0.002, respectively).

Conclusions

FNAB often produces false-negative results in patients with multiple malignant thyroid tumors, which results in reoperation in many cases. False-negative FNAB results are rare in patients with a solitary tumor. Because of the low predictive capacity of FNAB for thyroid cancer in patients with multiple thyroid tumors, total thyroid excision should be considered in most cases despite a "negative" (no malignant) FNAB result.     

Fabrication of DNA microarrays onto poly(methyl methacrylate) with ultraviolet patterning and microfluidics for the detection of low-abundant point mutations

We have developed a simple ultraviolet (UV)-photomodification protocol using poly(methyl methacrylate) and polycarbonate to produce functional scaffolds consisting of carboxylic groups that allow covalent attachment of amine-terminated oligonucleotide probes to these surface groups through carbodiimide coupling. Use of the photomodification procedure coupled to microfluidics allowed for the rapid generation of medium-density DNA microarrays. The method reported herein involves the use of poly(dimethylsiloxane) microchannels reversibly sealed to photomodified poly(methyl methacrylate) surfaces to serve as stencils for patterning the oligonucleotide probes. After array construction, the poly(dimethylsiloxane) stencil is rotated 90 degrees to allow interrogation of the array using microfluidics. The photomodification process for array fabrication involves only three steps: (1) broadband UV exposure of the polymer surface, (2) carbodiimide coupling of amine-terminated oligonucleotide probes to the surface (via an amide bond), and (3) washing of the surface. The density of probes attached to this activated surface was found to be approximately 41pmolcm(-2), near the steric-saturation limit for short oligonucleotide probes. We demonstrate the use of this procedure for screening multiple KRAS2 mutations possessing high diagnostic value for colorectal cancers. A ligase detection reaction/universal array assay was carried out using parallel detection of two different low-abundant DNA point mutations in KRAS2 oncogenes with the allelic composition evaluated at one locus. Four zip code probes immobilized onto the poly(methyl methacrylate) surface directed allele-specific ligation products containing mutations in the KRAS2 gene (12.2D, 12.2A, 12.2V, and 13.4D) to the appropriate address of a universal array with minimal amounts of cross-hybridization or misligation.     

Synthetic promoter libraries for Corynebacterium glutamicum

The ability to modulate gene expression is an important genetic tool in systems biology and biotechnology. Here, we demonstrate that a previously published easy and fast PCR-based method for modulating gene expression in lactic acid bacteria is also applicable to Corynebacterium glutamicum. We constructed constitutive promoter libraries based on various combinations of a previously reported C. glutamicum -10 consensus sequence (gngnTA(c/t)aaTgg) and the Escherichia coli -35 consensus, either with or without an AT-rich region upstream. A promoter library based on consensus sequences frequently found in low-GC Gram-positive microorganisms was also included. The strongest promoters were found in the library with a -35 region and a C. glutamicum -10 consensus, and this library also represents the largest activity span. Using the alternative -10 consensus TATAAT, which can be found in many other prokaryotes, resulted in a weaker but still useful promoter library. The upstream AT-rich region did not appear to affect promoter strength in C. glutamicum. In addition to the constitutive promoters, a synthetic inducible promoter library, based on the E. coli lac-promoter, was constructed by randomizing the 17-bp spacer between -35 and -10 consensus sequences and the sequences surrounding these. The inducible promoter library was shown to result in β-galactosidase activities ranging from 284 to 1,665 Miller units when induced by IPTG, and the induction fold ranged from 7–59. We find that the synthetic promoter library (SPL) technology is convenient for modulating gene expression in C. glutamicum and should have many future applications, within basic research as well as for optimizing industrial production organisms.     

Circadian Mechanisms of Food Anticipatory Rhythms in Rats Fed Once or Twice Daily: Clock Gene and Endocrine Correlates

Circadian clocks in many brain regions and peripheral tissues are entrained by the daily rhythm of food intake. Clocks in one or more of these locations generate a daily rhythm of locomotor activity that anticipates a regular mealtime. Rats and mice can also anticipate two daily meals. Whether this involves 1 or 2 circadian clocks is unknown. To gain insight into how the circadian system adjusts to 2 daily mealtimes, male rats in a 12∶12 light-dark cycle were fed a 2 h meal either 4 h after lights-on or 4 h after lights-off, or a 1 h meal at both times. After 30 days, brain, blood, adrenal and stomach tissue were collected at 6 time points. Multiple clock genes from adrenals and stomachs were assayed by RT-PCR. Blood was assayed for corticosterone and ghrelin. Bmal1 expression was quantified in 14 brain regions by in situ hybridization. Clock gene rhythms in adrenal and stomach from day-fed rats oscillated in antiphase with the rhythms in night-fed rats, and at an intermediate phase in rats fed twice daily. Corticosterone and ghrelin in 1-meal rats peaked at or prior to the expected mealtime. In 2-meal rats, corticosterone peaked only prior the nighttime meal, while ghrelin peaked prior to the daytime meal and then remained elevated. The olfactory bulb, nucleus accumbens, dorsal striatum, cerebellum and arcuate nucleus exhibited significant daily rhythms of Bmal1 in the night-fed groups that were approximately in antiphase in the day-fed groups, and at intermediate levels (arrhythmic) in rats anticipating 2 daily meals. The dissociations between anticipatory activity and the peripheral clocks and hormones in rats anticipating 2 daily meals argue against a role for these signals in the timing of behavioral rhythms. The absence of rhythmicity at the tissue level in brain regions from rats anticipating 2 daily meals support behavioral evidence that circadian clock cells in these tissues may reorganize into two populations coupled to different meals.     

Formation of Cystine Slipknots in Dimeric Proteins

We consider mechanical stability of dimeric and monomeric proteins with the cystine knot motif. A structure based dynamical model is used to demonstrate that all dimeric and some monomeric proteins of this kind should have considerable resistance to stretching that is significantly larger than that of titin. The mechanisms of the large mechanostability are elucidated. In most cases, it originates from the induced formation of one or two cystine slipknots. Since there are four termini in a dimer, there are several ways of selecting two of them to pull by. We show that in the cystine knot systems, there is strong anisotropy in mechanostability and force patterns related to the selection. We show that the thermodynamic stability of the dimers is enhanced compared to the constituting monomers whereas machanostability is either lower or higher.