Insights into the role of components of the tumor microenvironment in oral carcinoma call for new therapeutic approaches

The research on oral cancer has focused mainly on the cancer cells, their genetic changes and consequent phenotypic modifications. However, it is increasingly clear that the tumor microenvironment (TME) has been shown to be in a dynamic state of inter-relations with the cancer cells. The TME contains a variety of components including the non-cancerous cells (i.e., immune cells, resident fibroblasts and angiogenic vascular cells) and the ECM milieu [including fibers (mainly collagen and fibronectin) and soluble factors (i.e., enzymes, growth factors, cytokines and chemokines)]. Thus, it is currently assumed that TME is considered a part of the cancerous tissue and the functionality of its key components constitutes the setting on which the hallmarks of the cancer cells can evolve. Therefore, in terms of controlling a malignancy, one should control the growth, invasion and spread of the cancer cells through modifications in the TME components. This mini review focuses on the TME as a diagnostic approach and reports the recent insights into the role of different TME key components [such as carcinoma-associated fibroblasts (CAFs) and inflammation (CAI) cells, angiogenesis, stromal matrix molecules and proteases] in the molecular biology of oral carcinoma. Furthermore, the impact of TME components on clinical outcomes and the concomitant need for development of new therapeutic approaches will be discussed.     

On the 13C/12C isotopic signal of day and night respiration at the mesocosm level

While there is currently intense effort to examine the ¹³C signal of CO₂ evolved in the dark, less is known on the isotope composition of day‐respired CO₂. This lack of knowledge stems from technical difficulties to measure the pure respiratory isotopic signal: day respiration is mixed up with photorespiration, and there is no obvious way to separate photosynthetic fractionation (pure c_i/c_a effect) from respiratory effect (production of CO₂ with a different δ¹³C value from that of net‐fixed CO₂) at the ecosystem level. Here, we took advantage of new simple equations, and applied them to sunflower canopies grown under low and high [CO₂]. We show that whole mesocosm‐respired CO₂ is slightly ¹³C depleted in the light at the mesocosm level (by 0.2–0.8‰), while it is slightly ¹³C enriched in darkness (by 1.5–3.2‰). The turnover of the respiratory carbon pool after labelling appears similar in the light and in the dark, and accordingly, a hierarchical clustering analysis shows a close correlation between the ¹³C abundance in day‐ and night‐evolved CO₂. We conclude that the carbon source for respiration is similar in the dark and in the light, but the metabolic pathways associated with CO₂ production may change, thereby explaining the different ¹²C/¹³C respiratory fractionations in the light and in the dark.     

Diversity and identification of methanogenic archaea and sulphate-reducing bacteria in sediments from a pristine tropical mangrove

Mangrove sediments are anaerobic ecosystems rich in organic matter. This environment is optimal for anaerobic microorganisms, such as sulphate-reducing bacteria and methanogenic archaea, which are responsible for nutrient cycling. In this study, the diversity of these two functional guilds was evaluated in a pristine mangrove forest using denaturing gradient gel electrophoresis (DGGE) and clone library sequencing in a 50 cm vertical profile sampled every 5.0 cm. DGGE profiles indicated that both groups presented higher richness in shallow samples (0–30 cm) with a steep decrease in richness beyond that depth. According to redundancy analysis, this alteration significantly correlated with a decrease in the amount of organic matter. Clone library sequencing indicated that depth had a strong effect on the selection of dissimilatory sulphate reductase (dsrB) operational taxonomic units (OTUs), as indicated by the small number of shared OTUs found in shallow (0.0 cm) and deep (40.0 cm) libraries. On the other hand, methyl coenzyme-M reductase (mcrA) libraries indicated that most of the OTUs found in the shallow library were present in the deep library. These results show that these two guilds co-exist in these mangrove sediments and indicate important roles for these organisms in nutrient cycling within this ecosystem.     

Genetic portrait of Lisboa immigrant population from Cabo Verde with mitochondrial DNA analysis

Journal of Genetics -     

Reactive Oxygen Species and Cellular Interactions Between Mycosphaerella fijiensis and Banana

Globally, the banana plant (Musa spp) is the fourth most important crop after rice, wheat and corn (based on production in tons). It is cultivated in more than 100 tropical and subtropical countries, mainly by small producers and is a fundamental food source for millions of people. Black leaf streak disease (BLSD), caused by Mycosphaerella fijiensis Morelet (sexual phase) or Paracercospora fijiensis (Morelet) Deighton (asexual phase), is the main disease affecting the world??s banana culture. This disease has a wide geographical distribution accounting for losses exceeding 50% of global banana production. We conducted a comparative histocytological study on the kinetics of the infection process using three banana genotypes with phenotypes that differ in resistance to BLSD: Grand Naine (Susceptible), Pisang Madu (Partially Resistant) and Calcutta 4 (Resistant). Experiments were conducted under controlled conditions with the objective of characterizing the cellular interaction processes between M. fijiensis and Musa acuminata. Conidia germination occurred 24 hours after inoculation. Germination rates were high (97%) and there were no significant differences between the three genotypes (P?>?0.147). The Peroxidase enzyme and H₂O₂ were associated with a hypersensitivity-like reaction in the resistant genotype Calcutta 4, indicating a possible role of the enzyme or its product as defense mechanisms against M. fijiensis in banana plants.     

Ingestion of saliva during carbohydrate feeding by Lutzomyia longipalpis (Diptera; Psychodidae)

The aim of this study was to obtain experimental evidence that phlebotomine saliva is actually ingested during the carbohydrate ingestion phase (before and after blood digestion). The ingestion of carbohydrate was simulated as it occurs in the field by offering the insects balls of cotton soaked in sucrose, sucrose crystals or orange juice cells. The results obtained here showed that ingestion occurred under each condition investigated, as indicated by the presence of apyrase, an enzyme used as a marker to detect saliva in the insect gut and/or carbohydrate sources. Saliva ingestion by phlebotomine during the carbohydrate ingestion phase is important to explain how it could promote starch digestion and to trigger Leishmania promastigotes to follow a differentiation pathway as proposed previously by some authors.     

Effect of insulin-like growth factor-I on some quality traits and fertility of cryopreserved ovine semen

The objective was to evaluate the effects of insulin-like growth factor-I (IGF-I) on the quality and fertility of frozen/thawed ovine semen. Five rams (five ejaculates/ram) were used for evaluation of semen parameters. Before cryopreservation, ejaculates were divided into four aliquots and extended with Tris alone or supplemented with human IGF-I (50, 100, or 250 ng/mL). Semen was evaluated immediately after thawing (T0), after 1 h (T1) and 2 h (T2) post-incubation at 37 °C. The percentage of live cells (fluorescence analysis-calcein and ethidium), acrosome integrity (NAR) and motility were analyzed, and hypo-osmotic swelling tests (HOST) were used to evaluate membrane resistance. In addition, AI was performed using 121 ewes to compare the optimal concentration of IGF-I vs. Tris alone on pregnancy rates after laparoscopic insemination. Pregnancy diagnosis was performed by transrectal ultrasonography. After 1 and 2 h post-incubation, in every group, percentage motile sperm, NAR and HOST decreased compared to semen at T0. Motility was higher (P < 0.05) in the IGF-I 100 and IGF-I 250 groups when compared to the IGF-I 50 and Tris groups (76.2 and 74.4% vs. 66.2 and 64.4 percent, respectively) at T0, after 1 h (67 and 63.6% vs. 56.2 and 54.7%) and 2 h post-incubation (58.2 and 55.8% vs. 48 and 47.2%). Furthermore, viability was higher (P < 0.05) in the insulin-like growth factor-I (IGF-I) 100 and IGF-I 250 groups than in the IGF-I 50 and Tris groups (88.7 and 88.3% vs. 76.6 and 77.6%, respectively) at T0. There was no difference (P > 0.05) in NAR or hypo-osmotic swelling tests (HOST) among groups. There were no differences (P > 0.05) in fertility between the IGF-I 100 and Tris groups. In conclusion, IGF-I improved subjective sperm motility and structural integrity of the plasma membrane without a significant effect on 45-day pregnancy rates after laparoscopic insemination of ewes with frozen-thawed semen.     

Cellulolytic bacteria from soils in harsh environments

It is believed that the exposure of organisms to harsh climate conditions may select for differential enzymatic activities, making the surviving organisms a very promising source for bioprospecting. Soil bacteria play an important role in degradation of organic matter, which is mostly due to their ability to decompose cellulose-based materials. This work focuses on the isolation and identification of cellulolytic bacteria from soil found in two environments with stressful climate conditions (Antarctica and the Brazilian semi-arid caatinga). Cellulolytic bacteria were selected using enrichments at high and low temperatures (4 or 60°C) in liquid media (trypic soy broth—TSB and minimum salt medium—MM) supplemented with cellulose (1%). Many of the isolates (119 out of 254—46.9%) displayed the ability to degrade carboxymethyl-cellulose, indicating the presence of endoglucolytic activity, while only a minority of these isolates (23 out of 254—9.1%) showed exoglucolytic activity (degradation of avicel). The obtained isolates revealed a preferential endoglucolytic activity according to the temperature of enrichments. Also, the identification of some isolates by partial sequencing of the 16S rRNA gene indicated that the Bacteroidetes (e.g., Pedobacter, Chryseobacterium and Flavobacterium) were the main phylum of cellulolytic bacteria isolated from soil in Antarctica; the Firmicutes (e.g., Bacillus) were more commonly isolated from samples from the caatinga; and Actinobacteria were found in both types of soil (e.g., Microbacterium and Arthrobacter). In conclusion, this work reports the isolation of bacteria able to degrade cellulose-based material from soil at very low or very high temperatures, a finding that should be further explored in the search for cellulolytic enzymes to be used in the bioenergy industry.