Modification of testicular and thyroid function by chronic exposure to short photoperiod: a comparison in four rodent species

Exposure of male Syrian hamsters (Mesocricetus auratus) for 10 weeks to short photoperiod (SP) providing 10 hr light: 14 hr darkness (10:14 LD) produced a significant reduction in the weights of the reproductive organs, plasma thyroxine (T4) levels and free T4 index (FT4I) compared to the values of animals exposed to long photoperiod (LP, 14:10 LD). C57bl male house mice (Mus musculus) kept in SP (10:14 LD) had reproductive organ weights equivalent to those of mice kept in long days (14:10 LD) and lower T3 uptake (T3U) values. Male gerbils (Meriones unguiculatus) exposed to 13 weeks of SP (10:14 LD) had lower body weights, testes and seminal vesicle weights and higher T3U values compared to LP (14:10 LD) controls. However, no effect was seen on plasma T4 and triiodothyronine (T3) values nor the FT4I and free T3 index (FT3I). White-footed male mice (Peromyscus leucopus) exposed to SP (8:16 LD) had significantly lower testes and seminal vesicle weights while plasma T4 and T3 levels were unaffected. Snell strain house mice (Mus musculus) exposed to SP (8:16 LD) had normal reproductive organ weights compared to the values of LP-exposed (16:8 LD) control animals. However, there was a significant depression in T3 and in the FT3I in the SP animals.     

What Do We Know About Metal Recycling Rates?

The recycling of metals is widely viewed as a fruitful sustainability strategy, but little information is available on the degree to which recycling is actually taking place. This article provides an overview on the current knowledge of recycling rates for 60 metals. We propose various recycling metrics, discuss relevant aspects of recycling processes, and present current estimates on global end‐of‐life recycling rates (EOL‐RR; i.e., the percentage of a metal in discards that is actually recycled), recycled content (RC), and old scrap ratios (OSRs; i.e., the share of old scrap in the total scrap flow). Because of increases in metal use over time and long metal in‐use lifetimes, many RC values are low and will remain so for the foreseeable future. Because of relatively low efficiencies in the collection and processing of most discarded products, inherent limitations in recycling processes, and the fact that primary material is often relatively abundant and low‐cost (which thereby keeps down the price of scrap), many EOL‐RRs are very low: Only for 18 metals (silver, aluminum, gold, cobalt, chromium, copper, iron, manganese, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, tin, titanium, and zinc) is the EOL‐RR above 50% at present. Only for niobium, lead, and ruthenium is the RC above 50%, although 16 metals are in the 25% to 50% range. Thirteen metals have an OSR greater than 50%. These estimates may be used in considerations of whether recycling efficiencies can be improved; which metric could best encourage improved effectiveness in recycling; and an improved understanding of the dependence of recycling on economics, technology, and other factors.     

Transfer and expression of the cryIVB and cryIVD genes of Bacillus thuringiensis subsp. israelensis in Bacillus sphaericus 2297

Abstract The genes encoding the CryIVB and CryIVD crystal polypeptides of B. thuringiensis subsp. israelensis were cloned indepently on a stable shuttle vector, and transfered into B. sphaericus 2297. Recombinant cells expressed the B. thuringiensis toxins during sporulation and were shown to be toxic to Aedes aegypti fourth instar larvae, whereas the parental strain was not.     

The ageing pineal gland and its physiological consequences.

Melatonin, the chief hormone of the pineal gland, is produced and secreted into the blood in a circadian manner with maximal production always occurring during the dark phase of the light:dark cycle. Whereas the 24h rhythm of melatonin production is very robust in young animals including humans, the cycle deteriorates during ageing. The rhythm of melatonin can be substantially preserved during ageing by restricting the food intake of experimental animals; this same treatment increases the life span of the animals. The exogenous administration of melatonin to non-food restricted animals also reportedly increases their survival. Moreover, melatonin has been shown to have immunoenhancing effects and oncostatic properties. The implication of these studies is that melatonin may have both direct and indirect beneficial effects in delaying ageing processes or it may retard the development of processes (e.g., immunodeficiency and tumor growth) which contribute to a reduced life span.     

The oncolytic peptide LTX-315 triggers necrotic cell death

The oncolytic peptide LTX-315 has been designed for killing human cancer cells and turned out to stimulate anti-cancer immune responses when locally injected into tumors established in immunocompetent mice. Here, we investigated the question whether LTX-315 induces apoptosis or necrosis. Transmission electron microscopy or morphometric analysis of chromatin-stained tumor cells revealed that LTX-315 failed to induce apoptotic nuclear condensation and rather induced a necrotic phenotype. Accordingly, LTX-315 failed to stimulate the activation of caspase-3, and inhibition of caspases by means of Z-VAD-fmk was unable to reduce cell killing by LTX-315. In addition, 2 prominent inhibitors of regulated necrosis (necroptosis), namely, necrostatin-1 and cycosporin A, failed to reduce LTX-315-induced cell death. In conclusion, it appears that LTX-315 triggers unregulated necrosis, which may contribute to its pro-inflammatory and pro-immune effects.     

The melatonin message: duration versus coincidence hypotheses

Whereas there is little doubt that melatonin is an important hormone which mediates the effects of the pineal gland, there is debate concerning the nature of the melatonin message which the animal interprets. This brief resume considers the two main features of the melatonin rhythm which the organism could "read" to determine whether it is in a long or a short day. The first scheme is what is referred to as the duration hypothesis. This hypothesis depends on the fact that the changing photoperiod likewise alters the duration of the daily melatonin peak and this signals the organism as to daylength and the appropriate endocrine adjustments are made. The second possibility depends on the synchronization of elevated melatonin levels with the sensitivity of a particular organ system to the melatonin peak; when this occurs the organ responds accordingly. Both the external and internal coincidence models are considered. The duration and coincidence models are fundamentally quite different. In the case of the former, the altered duration of the melatonin peak per se determines the response that will occur. In the case of the coincidence models, the elevated melatonin has a more passive role with the "decision" to respond being a function of end organ sensitivity. In the final analysis, it may be that organisms use a combination of absolute duration of the melatonin pulse, direction of change of the melatonin rhythm, and synchrony of peak melatonin with the increased sensitivity of the end organ before a response is forthcoming.