Comparative effects of trichothecene mycotoxins on bovine platelet function: Acetyl T-2 toxin,a more potent inhibitor than T-2 toxin

The effects of the trichothecene mycotoxins (acetyl T-2 toxin, T-2 toxin, HT-2 toxin, palmityl T-2 toxin, diacetoxyscirpenol (DAS), deoxynivalenol (DON), and T-2 tetraol) on bovine platelet function were examined in homologous plasma stimulated with platelet activating factor (PAF). The mycotoxins inhibited platelet function with the following order of potency: acetyl T-2 toxin > palmityl T-2 toxin = DAS > HT-2 toxin = T-2 toxin. While T-2 tetraol was completely ineffective as an inhibitor, DON exhibited minimal inhibitory activity at concentrations above 10×10^?4M. The stability of the platelet aggregates formed was significantly reduced in all mycotoxin treated platelets compared to that of the untreated PAF controls. It is suggested that the increased sensitivity of PAF stimulated bovine platelets to the more lipophilic mycotoxins may be related to their more efficient partitioning into the platelet membrane compared to the more hydrophilic compounds.     

Direct observation of phytoplankton, TEP and aggregates on polycarbonate filters using brightfield microscopy

There has been little use of standard (i.e. non-inverted) microscopesfor observing and counting phytoplankton in filtered water samplesusing brightfield white light illumination due to light interferencefrom the filters. If filters are placed on newly designed frostedslides (Cyto-clear, Poretics Corp.), however, phytoplanktoncan be viewed directly on the surfaces of polycarbonate filtersunder brightfield illumination. Lake and seawater samples wereused to show that samples stained with alcian blue (to identifythe presence of paniculate polysaccharides) and analyzed withwhite light can also be simultaneously stained with fluorochromes(i.e. DAPI and acridine orange) for additional examination ofthe sample using fluorescent techniques. Black filters, whichare necessary for epifluorescent techniques, did not interferewith brightfield viewing. Using double staining techniques,we found that transparent exopolymer particles (TEP) recentlydiscovered in marine systems are also present in lakes. Notall aggregates in the fresh and seawater systems absorbed thealcian blue stain, however, indicating that not all amorphousparticles in these systems are rich in negatively charged polysaccharides.     

Linear skeletal extension rates in two species of Diploria from high-latitude reefs in Bermuda

X-radiography was used to study annual linear skeletal extension rates of the reef-building scleractinian corals Diploria strigosa and Diploria labyrinthiformis from the high-latitude reefs of Bermuda. Coral samples for X-radiography were collected from seven localities of varying biotopes and depths around the Bermuda platform and band couplets were measured. Mean extension rates of both species were highest on inshore and nearshore reefs, gradually decreasing towards the edge of the Bermuda platform and onto the fore-reef slope. Extension rates of D. labyrinthiformis were statistically higher than those of D. strigosa at three localities, while at the other four, the rates of both species were not statistically separable. extension rates of d. labyrinthiformis were statistically higher than D. strigosa within depths of 20 m and 32 m but not statistically separable at 3 m and 6 m depths. Extension rates of both species decreased significantly with increasing depth (r ²=0.92, P<0.03 for D. labyrinthiformis and r ²=0.95, P<0.02 for D. strigosa). Each species showed an inverse curvilinear relationship between extension rate and depth, the rate of change (i.e. slope) being the same for each species. Comparison of extension rates of each species from Berumuda with published rates of these species from lower latitudes showed an inverse relationship between extension rate and latitude.     

Multiple copies of genes coding for electron transport proteins in the bacterium Nitrosomonas europaea.

The genome of Nitrosomonas europaea contains at least three copies each of the genes coding for hydroxylamine oxidoreductase (HAO) and cytochrome c554. A copy of an HAO gene is always located within 2.7 kb of a copy of a cytochrome c554 gene. Cytochrome P-460, a protein that shares very unusual spectral features with HAO, was found to be encoded by a gene separate from the HAO genes.     

A surplus no more? Variation in krill availability impacts reproductive rates of Antarctic baleen whales

The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since the 1970s. Rapid warming of the Western Antarctic Peninsula (WAP) over the past 50 years has resulted in decreased seasonal ice cover and a reduction of krill. The latter is being exacerbated by a commercial krill fishery in the region. Despite this, humpback whale populations have increased but may be at a threshold for growth based on these human-induced changes. Understanding how climate-mediated variation in prey availability influences humpback whale population dynamics is critical for focused management and conservation actions. Using an 8-year dataset (2013–2020), we show that inter-annual humpback whale pregnancy rates, as determined from skin-blubber biopsy samples (n = 616), are positively correlated with krill availability and fluctuations in ice cover in the previous year. Pregnancy rates showed significant inter-annual variability, between 29% and 86%. Our results indicate that krill availability is in fact limiting and affecting reproductive rates, in contrast to the krill surplus hypothesis. This suggests that this population of humpback whales may be at a threshold for population growth due to prey limitations. As a result, continued warming and increased fishing along the WAP, which continue to reduce krill stocks, will likely impact this humpback whale population and other krill predators in the region. Humpback whales are sentinel species of ecosystem health, and changes in pregnancy rates can provide quantifiable signals of the impact of environmental change at the population level. Our findings must be considered paramount in developing new and more restrictive conservation and management plans for the Antarctic marine ecosystem and minimizing the negative impacts of human activities in the region.     

An extensive review on antifungal approaches in the treatment of mucormycosis

During the period of COVID-19, the occurrences of mucormycosis in immunocompromised patients have increased significantly. Mucormycosis (black fungus) is a rare and rapidly progressing fungal infection associated with high mortality and morbidity in India as well as globally. The causative agents for this infection are collectively called mucoromycetes which are the members of the order Mucorales. The diagnosis of the infection needs to be performed as soon as the occurrence of clinical symptoms which differs with types of Mucorales infection. Imaging techniques magnetic resonance imaging or computed tomography scan, culture testing, and microscopy are the approaches for the diagnosis. After the diagnosis of the infection is confirmed, rapid action is needed for the treatment in the form of antifungal therapy or surgery depending upon the severity of the infection. Delaying in treatment declines the chances of survival. In antifungal therapy, there are two approaches first-line therapy (monotherapy) and combination therapy. Amphotericin B ( 1 ) and isavuconazole ( 2 ) are the drugs of choice for first-line therapy in the treatment of mucormycosis. Salvage therapy with posaconazole ( 3 ) and deferasirox ( 4 ) is another approach for patients who are not responsible for any other therapy. Adjunctive therapy is also used in the treatment of mucormycosis along with first-line therapy, which involves hyperbaric oxygen and cytokine therapy. There are some drugs like VT-1161 ( 5 ) and APX001A ( 6 ), Colistin, SCH 42427, and PC1244 that are under clinical trials. Despite all these approaches, none can be 100% successful in giving results. Therefore, new medications with favorable or little side effects are required for the treatment of mucormycosis.     

The comparative genomics of T-box genes.

T-box genes are defined by the presence of a conserved sequence, the so-called T-box; this codes for the T-domain, which is involved in DNA-binding and protein dimerisation. Members of this gene family have been found in all metazoans, from diploblasts to humans, and mutations in T-box gene family members in humans have been linked to several congenital disorders. Sequencing of the complete genomes of a range of invertebrate and vertebrate species has allowed the classification of individual T-box genes into five subfamilies: Brachyury, T-brain1, Tbx1, Tbx2 and Tbx6. This review will largely focus on T-box genes identified in organisms whose genomes have been fully sequenced, emphasising how comparative studies of the T-box gene family will help to reveal the roles of these genes during development and in the adult.