An early fish oil-enriched diet reverses biochemical, liver and adipose tissue alterations in male offspring from maternal protein restriction in mice

Fetal programming is linked to adulthood metabolic and chronic diseases. We hypothesized that early fish oil (FO) intake would revert the programming responses in adult offspring. Pregnant mice were fed either standard chow (SC) or a low-protein diet (LP) throughout pregnancy/lactation. At weaning, the following groups were formed: SC and SC-FO, LP and LP-FO, which were fed SC or SC+FO, respectively. The LP offspring are predisposed to becoming fat, hypercholesterolemic and hyperglycemic. In addition, during adulthood, they become hypertensive with hepatic steatosis and have a high level of sterol regulatory element binding protein (SREBP-1). However, LP offspring that were fed an FO-enriched diet have decreased body mass (BM) gain and lower final BM. In addition, with this diet, these mice have improved lipid metabolism with a decrease in total cholesterol (TC) and triacylglyceride (TG) levels, reduced fat pad masses and reduced adipocyte size. Furthermore, these LP offspring show reduced liver structural damage of alanine aminotransferase (ALT), liver steatosis with low SREBP-1 protein expression and high peroxisome proliferator activity receptor-alpha expression, and improvement of blood pressure (BP) and tumor necrosis factor (TNF)-alpha level. Early fish oil intake has beneficial effects on the programming responses that control body fat pad, glucose and lipid metabolism, and liver and adipose tissue structure in adult programmed offspring.     

The effect of butenolide on behavioral and morphological changes in two marine fouling species, the barnacle Balanus amphitrite and the bryozoan Bugula neritina

Butenolide [5-octylfuran-2(5H)-one] is a very promising antifouling compound. Here, the effects of butenolide on larval behavior and histology are compared in two major fouling organisms, viz. cypris larvae of Balanus amphitrite and swimming larvae of Bugula neritina. Butenolide diminished the positive phototactic behavior of B. amphitrite (EC50=0.82 μg ml(-1)) and B. neritina (EC50=3 μg ml(-1)). Its effect on the attachment of cyprids of B. amphitrite was influenced by temperature, and butenolide increased attachment of larvae of B. neritina to the bottom of the experimental wells. At concentrations of 4 μg ml(-1) and 10 μg ml(-1), butenolide decreased attachment of B. amphitrite and B. neritina, respectively, but the effects were reversible within a certain treatment time. Morphologically, butenolide inhibited the swelling of secretory granules and altered the rough endoplasmic reticulum (RER) in the cement gland of B. amphitrite cyprids. In B. neritina swimming larvae, butenolide reduced the number of secretory granules in the pyriform-glandular complex.     

Latent transforming growth factor beta-binding proteins-2 and -3 inhibit the proprotein convertase 5/6A

The basic amino acid-specific proprotein convertase 5/6 (PC5/6) is an essential secretory protease, as knock-out mice die at birth and exhibit multiple homeotic transformation defects, including impaired bone morphogenesis and lung structure. Some of the observed defects were attributed to impaired processing of the TGFβ-like growth differentiating factor 11 precursor (proGdf11). In this work we present evidence that the latent TGFβ-binding proteins 2 and 3 (LTBP-2 and -3) inhibit the extracellular processing of proGdf11 by PC5/6A. This is partly due to the binding of LTBPs in the endoplasmic reticulum to the zymogen proPC5/6A, thus allowing the complex to exit the endoplasmic reticulum and be sequestered as an inactive zymogen in the extracellular matrix but not at the cell surface. This results in lower levels of PC5/6A in the media, without affecting those of PACE4, Furin, or a soluble form of PC7. The secreted soluble protease-specific activity of PC5/6A or a variant lacking the C-terminal Cys-rich domain (PC5/6-ΔCRD) is significantly decreased when co-expressed with LTBPs in cells. A similar enzymatic inhibition seems to apply to PACE4 and Furin. In situ hybridization analyses revealed extensive co-localization of PC5/6 and LTBP-3 mRNAs in mice at embryonic day 15.5 and post partum day 1. In conclusion, this is the first time that a zymogen of the proprotein convertases was shown to exit the endoplasmic reticulum in the presence of LTBPs, representing a potential novel mechanism for the regulation of PC5/6A activity, e.g. in tissues such as bone and lung where LTBP-3 and PC5/6 co-localize.     

Neospora caninum is associated with abortion in Algerian cattle

Neospora caninum is a major cause of abortion in cattle worldwide. However, little information is available for Algeria. Accordingly, 799 cattle from 87 farms in the north and northeast of Algeria were enrolled in a seroepidemiological survey. An indirect fluorescence antibody test (IFAT) revealed a seroprevalence of 19.6%. The animals were divided into 3 groups according to their breed: imported European cattle, local breeds, and crossed animals (European × local). Seroprevalences were 16.0%, 34.3%, and 18.6% in groups 1, 2, and 3, respectively. A case control study was performed to investigate the link between global seropositivity to N. caninum and abortion risk in those cattle farms. There was a significant (P < 0.01) association between the seroprevalence against N. caninum and the occurrence of abortion in those farms (odds ratio [OR] = 12.03). This was also observed at the individual level (OR = 2.79). The analysis of results according to the breed revealed a significant association between seroprevalence and abortion in groups 1 and 3, but not for group 2, despite the fact that the highest seroprevalence was observed in group 2. Cerebral tissues from 5 aborted fetuses were available for histology and polymerase chain reaction (PCR). One sample was found positive both by histology and by PCR, 2 samples were positive by PCR only, and 2 samples were negative in both tests.     

Biosynthesis of (R)-beta-tyrosine and its incorporation into the highly cytotoxic chondramides produced by Chondromyces crocatus

The chondramides are mixed non-ribosomal peptide/polyketide secondary metabolites produced by the myxobacterium Chondromyces crocatus Cm c5, which exhibit strong cytotoxic activity. On the basis of their striking structural similarity to the marine depsipeptides jaspamides, the chondramides have been assumed to incorporate a (R)-beta-tyrosine moiety, an expectation we confirm here. Thus, the recent sequencing of the chondramide biosynthetic gene cluster provided the opportunity to probe the shared origin of this unusual beta-amino acid. We demonstrate here that (R)-beta-tyrosine is produced directly from l-tyrosine by the aminomutase CmdF. Along with the tyrosine aminomutase SgcC4 from the C-1027 enediyne pathway, this enzyme belongs to a novel family of tyrosine aminomutases related to the ammonium lyase family of enzymes but exhibits opposite facial selectivity for the hydroxycinnamate intermediate. We also show that the adenylation (A) domain in the chondramide pathway, which activates the beta-tyrosine building block, exhibits the required preference for (R)-beta-tyrosine, further arguing against alternative origins for the moiety in the chondramides. Comparison to the (S)-beta-tyrosine specific A domain SgcC1 should enhance our understanding of the structural and stereochemical determinants guiding amino acid selection by non-ribosomal peptide synthetase multienzymes.     

Scaling up tests on virulence of the cassava green mite fungal pathogen <Emphasis Type="Italic">Neozygites tanajoae</Emphasis> (Entomophthorales: Neozygitaceae) under controlled conditions: first observations at the population level

Virulence of entomopathogens is often measured at the individual level using a single host individual or a group of host individuals. To what extent these virulence assessments reflect the impact of an entomopathogen on their host in the field remains largely untested, however. A methodology was developed to induce epizootics of the cassava green mite fungal pathogen Neozygites tanajoae under controlled conditions to evaluate population-level virulence of two (one Beninese and one Brazilian) isolates of the entomopathogen—which had shown similar individual-level virulence but different field impacts. In unrepeated separate experiments we inoculated mite-infested potted cassava plants with either 50 or 25 live mites (high and low inoculum) previously exposed to spores of N. tanajoae and monitored the development of fungal infections for each isolate under the same conditions. Both isolates caused mite infections and an associated decline in host mite populations relative to the control (without fungus) in all experiments, but prevalence of the fungus varied with isolate and increased with inoculum density. Peak infection levels were 90% for the Beninese isolate and 36% for the Brazilian isolate at high inoculum density, and respectively 17% and 25% at low inoculum density. We also measured dispersal from inoculated plants and found that spore dispersal increased with host infection levels, independent of host densities, whereas mite dispersal varied between isolates. These results demonstrate that epizootiology of N. tanajoae can be studied under controlled conditions and suggest that virulence tests at the population level may help to better predict performance of fungal isolates than individual-level tests.     

Analysis of de novo Golgi complex formation after enzyme-based inactivation

The Golgi complex is characterized by its unique morphology of closely apposed flattened cisternae that persists despite the large quantity of lipids and proteins that transit bidirectionally. Whether such a structure is maintained through endoplasmic reticulum (ER)-based recycling and auto-organization or whether it depends on a permanent Golgi structure is strongly debated. To further study Golgi maintenance in interphase cells, we developed a method allowing for a drug-free inactivation of Golgi dynamics and function in living cells. After Golgi inactivation, a new Golgi-like structure, containing only certain Golgi markers and newly synthesized cargoes, was produced. However, this structure did not acquire a normal Golgi architecture and was unable to ensure a normal trafficking activity. This suggests an integrative model for Golgi maintenance in interphase where the ER is able to autonomously produce Golgi-like structures that need pre-existing Golgi complexes to be organized as morphologically normal and active Golgi elements.