Alterations in enzyme and cytochrome profiles of Rana catesbeiana liver organelles during thyroxine-induced metamorphosis. Changes in membrane-localized phosphohydrolases, oxidoreductases, and cytochrome levels in response to in vivo thyroxine administration.

A primary objective of the present study has been to determine the changes which occur in Rana catesbeiana liver organelle membranes during thyroxine-induced metamorphosis. To this end, enzyme and cytochrome profiles were determined for mitochondria, microsomes, and nuclear membrane fractions isolated from livers of R. catesbeiana tadpoles which had been fasted for 6 days at 15 +/- 0.5 degrees and then immersed in thyroxine, 2.6 X 10(-8) M, for periods of up to 12 days at 23.5 +/- 0.4 degrees. The ratio of total succinate-cytochrome c reductase activity in the initial homogenate fraction to the total activity of this mitochondrial "marker" enzyme recovered in the final mitochondrial fraction remained constant, approximately 0.5, throughout the course of thyroxine treatment; however, after a 3- to 4-day latency the mitochondrial protein mass recovered per unit mass of initial homogenate protein was found to increase significantly (approximately 2-fold by Day 10 of thyroxine treatment). A similar increase was also observed in the yield of microsomal, but not nuclear membrane, protein mass as a function of thyroxine treatment. Prolonged thyroxine treatment (12 days) resulted in approximately 50% decreases in tadpole liver homogenate and microsomal NADH-cytochrome c reductase specific activities; in contrast, mitochondrial and nuclear membrane NADH-cytochrome c reductase specific activities were not altered under the same conditions. In addition, homogenate and microsomal NADPH-cytochrome c reductase specific activities were found to have increased significantly after 12 days of thyroxine treatment; however, the specific activity of NADPH-cytochrome c reductase in the mitochondrial fraction was unchanged. It was also observed that thyroxine treatment resulted in increases in homogenate and microsomal glucose-6-phosphatase specific activities, whereas the mitochondrial as well as nuclear membrane glucose-6-phosphatase specific activities remained unchanged. Furthermore, in contrast to homogenate and mitochondrial monoamine oxidase specific activities, which decreased 30 and 40%, respectively, as a consequence of thyroxine treatment (12 days), the succinate-cytochrome c reductase and oligomycin-sensitive Mg2+ ATPase specific activities determined for these fractions increased significantly. In all instances, changes as a result of thyroxine treatment in membrane-localized homogenate or organelle enzyme specific activities were apparent only after a 3- to 4-day initial latent period. The in vitro effects of thyroxine (10(-10) - 10(-5) M) on the membrane-localized enzyme activities examined in this study were either negligible or, as in the case of mitochondrial succinate-cytochrome c reductase and microsomal NADH-cytochrome c reductase, opposite to the changes observed in response to in vivo thyroxine treatment, with the exception of microsomal NADPH-cytochrome c reductase activity which was enhanced approximately 2-fold by 10(-5) M thyroxine...     

Developing indices of relative abundance for monitoring cave and ground wētā (Orthoptera) in southern beech forest,New Zealand

We sampled populations of forest-floor dwelling cave and ground wētā using footprint tracking tunnels and spotlight transect counts in southern beech forest, New Zealand. Samples were compared to estimates of wētā density based on mark–recapture estimates from 25?m² enclosures. Both activity indices captured variability in cave wētā in time and space, were strongly correlated with each other, and have the potential for monitoring cave wētā activity levels. Comparisons between indices and cave wētā density estimates were equivocal, as recapture rates were too low to calculate high-resolution density estimates. We also found that cave wētā counts had a curved relationship increasing with temperature, and a negative relationship with increasing shrub and woody debris cover. Based on these preliminary results, tracking tunnels could be a viable method of monitoring cave wētā as they appear more efficient than transect counts and are relatively inexpensive. However, further calibration trials are needed to determine if indices mirror robust population density estimates.     

Complementation tests between mutations in the phosphatespecific transport region ofEscherichia coli

Complementation between mutants impaired in inorganic phosphate (Pi) transport via the phosphate-specific transport (PST) system was studied. For that purpose the transport of Pi via the alternative Pi transport (PIT) system was bioenergetically arrested. Complementation was found betweenpstB andphoT mutations, whereas each of these mutations failed to complement with aphoS mutation. The data obtained confirm previous studies in which the inducibility of alkaline phosphatase was used to determine complementation and indicated a polar effect of thephoS mutation onpstB andphoT.     

Apoptosis-inducing antifungal peptides and proteins

Despite the availability of various classes of antimycotics, the treatment of patients with systemic fungal infections is challenging. Therefore the development of new antifungals is urgently required. Promising new antifungal candidates are antimicrobial peptides. In the present review, we provide an overview of antifungal peptides isolated from plants, insects, amphibians and mammals that induce apoptosis. Their antifungal spectrum, mode of action and toxicity are discussed in more detail.     

Copy number alterations and allelic ratio in relation to recurrence of rectal cancer

Background

In rectal cancer, total mesorectal excision surgery combined with preoperative (chemo)radiotherapy reduces local recurrence rates but does not improve overall patient survival, a result that may be due to the harmful side effects and/or co-morbidity of preoperative treatment. New biomarkers are needed to facilitate identification of rectal cancer patients at high risk for local recurrent disease. This would allow for preoperative (chemo)radiotherapy to be restricted to high-risk patients, thereby reducing overtreatment and allowing personalized treatment protocols. We analyzed genome-wide DNA copy number (CN) and allelic alterations in 112 tumors from preoperatively untreated rectal cancer patients. Sixty-six patients with local and/or distant recurrent disease were compared to matched controls without recurrence. Results were validated in a second cohort of tumors from 95 matched rectal cancer patients. Additionally, we performed a meta-analysis that included 42 studies reporting on CN alterations in colorectal cancer and compared results to our own data.

Results

The genomic profiles in our study were comparable to other rectal cancer studies. Results of the meta-analysis supported the hypothesis that colon cancer and rectal cancer may be distinct disease entities. In our discovery patient study cohort, allelic retention of chromosome 7 was significantly associated with local recurrent disease. Data from the validation cohort were supportive, albeit not statistically significant, of this finding.

Conclusions

We showed that retention of heterozygosity on chromosome 7 may be associated with local recurrence in rectal cancer. Further research is warranted to elucidate the mechanisms and effect of retention of chromosome 7 on the development of local recurrent disease in rectal cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1550-0) contains supplementary material, which is available to authorized users.     

Nitric oxide myoglobin: Crystal structure and analysis of ligand geometry

The structure of the ferrous nitric oxide form of native sperm whale myoglobin has been determined by X-ray crystallography to 1.7 Å resolution. The nitric oxide ligand is bent with respect to the heme plane: the Fe-N-O angle is 112°. This angle is smaller than those observed in model compounds and in lupin leghemoglobin. The exact angle appears to be influenced by the strength of the proximal bond and hydrogen bonding interactions between the distal histidine and the bound ligand. Specifically, the N_ϵ atom of histidine⁶⁴ is located 2.8 Å away from the nitrogen atom of the bound ligand, implying electrostatic stabilization of the FeNO complex. This interpretation is supported by mutagenesis studies. When histidine⁶⁴ is replaced with apolar amino acids, the rate of nitric oxide dissociation from myoglobin increases tenfold. Proteins 30:352–356, 1998. © 1998 Wiley-Liss, Inc.     

17. W. Brucker und H.-G. Rohde: Zum RNS-Stoffwechsel von Datura- Gewebe nach einer Röntgenbestrahlung

• 1 . Es wird über die Bestrahlung einer crown-gall-Gewebekultur aus Datura innoxia (in vitro), Stamm Px, mit subletalen Röntgendosen und die biochemische Analyse des RNS-Nucleotidmetabolismus zu verschiedenen Zeiten post irradiationem berichtet.
• 2 . Eine Röntgenbestrahlung (200 kV, 20 mA, DL 195 R/min) mit 3000 R vermindert das Wachstum des untersuchten Gewebes (Frischgewichtszunahme) in 14 Tagen um rund 60%.
• 3 . Die applizierte Strahlendosis hat keinen Einfluß auf die absoluten Nu-cleotidmengen und die Nucleotidzusammensetzung der RNS.
• 4 . Der Einbau von KH₂³²PO₄ in die einzelnen Nucleotide (spezifische Aktivität) der RNS zeigt 8 Stunden nach der Bestrahlung und der ³²P-Applikation eine gleichmäßige, radiogene Verminderung um 35% gegenüber den unbestrahlten Kontrollen.
• 5 . Im RNS-Nucleotidstoffwechsel tritt 24 bis 48 Stunden nach der ³²P-Zugabe und post irrad. dagegen eine unterschiedliche radiogene Beeinflußbarkeit der einzelnen Nucleotide auf:

• a) Der ³²P-Einbau in Adenylsäure bleibt praktisch unbeeinflußt.
• b) Der Metabolismus von Cytidylsäure und Guanylsäure wird um rund 25% gehemmt.
• c) Der Phosphateinbau in Uridylsäure ist gegenüber den Kontrollen um 60% gefördert.

• 6 . Für eine fundierte Erklärung der bisherigen Beobachtungen müssen weitere Versuchsergebnisse abgewartet werden.