Best Management Practices for Internal Parasite Control in Small Ruminants

Abstract Internal parasites represent a significant obstacle to a profitable and sustainable US goat industry. In some states, internal parasites are a year-round problem, while in others, they are a more seasonal challenge. Traditionally, parasite control methods relied heavily on antiparasitic drugs called anthelmintics or dewormers. Continued use and misuse of these drugs have resulted in increasingly resistant worm populations, necessitating more holistic or integrated methods of parasite control. A combination of practices will usually be necessary to achieve a satisfactory level of control. This paper discusses best management practices for controlling internal parasites in small ruminants, including pasture and grazing management, nutrition, zero grazing, and genetic selection, targeted selective treatment (TST), bioactive forages (e.g., sericea lespedeza) and copper oxide wire particles. Because the judicious use of anthelmintics is essential to effective parasite control, the paper additionally discusses the proper use of antiparasitic drugs, including how to measure and manage drug resistance. Keywords: Best Management Practices, Internal Parasites, Parasite Control, Small Ruminant

Marketing Toward the Future

Abstract United States goat producers face many challenges with regards to marketing. Although the demand for goat products is increasing, the market is fractured. There is a general lack of infrastructure and many producers do not sell their animals or products for fair or profitable prices. Production costs are too high, and there is a need to improve production efficiency. Imports pose a challenge to US goat producers, as domestic production cannot compete with the availability and lower cost of imports. Government regulations hinder market development because non-commercial slaughter is an important aspect of goat marketing, and regulations keep many dairy goat producers from developing a commercial enterprise. In order for the US goat industry to expand and meet the growing demand for products, producers need to combine efficient production practices with profitable marketing strategies. Keywords: Marketing, Marketing Strategies, Goat Meat Marketing, Dairy Marketin

Untersuchungen zur Vielfalt und Funktion von Antibiotika im Ökosystem der Blattschneiderameisen

Leaf cutting ants are member of a multitrophic system. They are cultivating the garden fungus Leucoagaricus gongylophorus, which serves them as major food source. This mutualistic symbiosis is threatened by several pathogens. The ants are therefore defending their colony by removing any suspicious material from the fungus garden into waste chambers and additionally by using chemical arms. Beside their own antimicrobial metabolites, symbiotic Actinomyces are supporting this survival conflict with their antibiotics. It became evident, that complex microbial communities are part of the whole live style of leaf cutting ants. Beside their mutualistic role, the involved microorganisms pursue selfish interests by using secondary metabolites to hinder other competing symbionts of the leaf cutting ants. A new method to easily identify microbial chemicals involved in leaf cutting ants’ ecosystems has been established. Antimycins, actinomycins and valinomycins were identified. The potential of some of these antibiotics to shape the complex microbial communities present in the ants’ nest has been tested. Beside pathogens also Actinomyces-symbionts and the garden fungus were inhibited. For the first time it was possible to directly detect known antibiotics in the waste material and on the cuticle of Acromyrmex ants. A plasmid for future investigations on the uptake of Actinomyces by leaf cutting ants has been constructed. Feeding studies with labeled compounds helped to investigate the biosynthesis of the 3-aminosalicylic acid-unit of the antimycins which apparently involves a shift of the carboxyl group of the anthranilic acid. Additionally it was shown that the antimycins already decompose under weak alkaline conditions, generating γ-butyrolactones

Coordinate regulation of antimycin and candicidin biosynthesis

Streptomyces species produce an incredible array of high-value specialty chemicals and medicinal therapeutics. A single species typically harbors ~30 biosynthetic pathways, but only a mere handful of them are expressed in the laboratory, thus poor understanding of how natural products biosynthesis is regulated is a major bottleneck in drug discovery. Antimycins are a large family of anticancer compounds widely produced by Streptomyces species and their regulation is atypical compared to that of most other natural products. Here we demonstrate that antimycin production by Streptomyces albus S4 is regulated by FscRI, a PAS-LuxR-family cluster-situated regulator of the polyene antifungal agent, candicidin. We report that heterologous production of antimycins by Streptomyces coelicolor is dependent on FscRI and show that FscRI activates transcription of key biosynthetic genes. We also demonstrate through ChIP sequencing that FscRI regulation is direct and we provide evidence to suggest that this regulation strategy is conserved and unique to short form antimycin gene clusters. Our study provides direct in vivo evidence for cross-regulation of disparate biosynthetic gene clusters specifying unrelated natural products and expands the paradigmatic understanding of the regulation of secondary metabolism

Genome analysis of two Pseudonocardia phylotypes associated with Acromyrmex leafcutter ants reveals their biosynthetic potential

The attine ants of South and Central America are ancient farmers, having evolved a symbiosis with a fungal food crop >50 million years ago. The most evolutionarily derived attines are the Atta and Acromyrmex leafcutter ants, which harvest fresh leaves to feed their fungus. Acromyrmex and many other attines vertically transmit a mutualistic strain of Pseudonocardia and use antifungal compounds made by these bacteria to protect their fungal partner against co-evolved fungal pathogens of the genus Escovopsis. Pseudonocardia mutualists associated with the attines Apterostigma dentigerum and Trachymyrmex cornetzi make novel cyclic depsipeptide compounds called gerumycins, while a mutualist strain isolated from derived Acromyrmex octospinosus makes an unusual polyene antifungal called nystatin P1. The novelty of these antimicrobials suggests there is merit in exploring secondary metabolites of Pseudonocardia on a genome-wide scale. Here we report a genomic analysis of the Pseudonocardia phylotypes Ps1 and Ps2 that are consistently associated with Acromyrmex ants collected in Gamboa, Panama. These were previously distinguished solely on the basis of 16S rRNA gene sequencing but genome sequencing of five Ps1 and five Ps2 strains revealed that the phylotypes are distinct species and each encodes between 11-15 secondary metabolite biosynthetic gene clusters (BGCs). There are signature BGCs for Ps1 and Ps2 strains and some that are conserved in both. Ps1 strains all contain BGCs encoding nystatin P1-like antifungals, while the Ps2 strains encode novel nystatin-like molecules. Strains show variations in the arrangement of these BGCs that resemble those seen in gerumycin gene clusters. Genome analyses and invasion assays support our hypothesis that vertically transmitted Ps1 and Ps2 strains have antibacterial activity that could help shape the cuticular microbiome. Thus, our work defines the Pseudonocardia species associated with Acromyrmex ants and supports the hypothesis that Pseudonocardia species could provide a valuable source of new antimicrobials

Analysis of the bacterial communities associated with two ant-plant symbioses.

Insect fungiculture is practiced by ants, termites, beetles, and gall midges and it has been suggested to be widespread among plant-ants. Some of the insects engaged in fungiculture, including attine ants and bark beetles, are known to use symbiotic antibiotic-producing actinobacteria to protect themselves and their fungal cultivars against infection. In this study, we analyze the bacterial communities on the cuticles of the plant-ant genera Allomerus and Tetraponera using deep sequencing of 16S rRNA. Allomerus ants cultivate fungus as a building material to strengthen traps for prey, while Tetraponera ants cultivate fungus as a food source. We report that Allomerus and Tetraponera microbiomes contain >75% Proteobacteria and remarkably the bacterial phyla that dominate their cuticular microbiomes are very similar despite their geographic separation (South America and Africa, respectively). Notably, antibiotic-producing actinomycete bacteria represent a tiny fraction of the cuticular microbiomes of both Allomerus and Tetraponera spp. and instead they are dominated by γ-proteobacteria Erwinia and Serratia spp. Both these phyla are known to contain antibiotic-producing species which might therefore play a protective role in these ant-plant systems

Regulation of antimycin biosynthesis by the orphan ECF RNA polymerase sigma factor σ (AntA.).

Antimycins are an extended family of depsipeptides that are made by filamentous actinomycete bacteria and were first isolated more than 60 years ago. Recently, antimycins have attracted renewed interest because of their activities against the anti-apoptotic machineries inside human cells which could make them promising anti-cancer compounds. The biosynthetic pathway for antimycins was recently characterised but very little is known about the organisation and regulation of the antimycin (ant) gene cluster. Here we report that the ant gene cluster in Streptomyces albus is organized into four transcriptional units; the antBA, antCDE, antGF and antHIJKLMNO operons. Unusually for secondary metabolite clusters, the antG and antH promoters are regulated by an extracytoplasmic function (ECF) RNA polymerase sigma factor named σ (AntA) which represents a new sub-family of ECF σ factors that is only found in antimycin producing strains. We show that σ (AntA) controls production of the unusual precursor 3-aminosalicylate which is absolutely required for the production of antimycins. σ (AntA) is highly conserved in antimycin producing strains and the -10 and -35 elements at the σ (AntA) regulated antG and antH promoters are also highly conserved suggesting a common mechanism of regulation. We also demonstrate that altering the C-terminal Ala-Ala residues found in all σ (AntA) proteins to Asp-Asp increases expression of the antFG and antGHIJKLMNO operons and we speculate that this Ala-Ala motif may be a signal for the protease ClpXP

Chemical warfare between leafcutter ant symbionts and a co-evolved pathogen

Acromyrmex leafcutter ants form a mutually beneficial symbiosis with the fungus Leucoagaricus gongylophorus and with Pseudonocardia bacteria. Both are vertically transmitted and actively maintained by the ants. The fungus garden is manured with freshly cut leaves and provides the sole food for the ant larvae, while Pseudonocardia cultures are reared on the ant-cuticle and make antifungal metabolites to help protect the cultivar against disease. If left unchecked, specialized parasitic Escovopsis fungi can overrun the fungus-garden and lead to colony collapse. We report that Escovopsis upregulates the production of two specialized metabolites when it infects the cultivar. These compounds inhibit Pseudonocardia and one, shearinine D, also reduces worker behavioral defences and is ultimately lethal when it accumulates in ant tissues. Our results are consistent with an active evolutionary arms race between Pseudonocardia and Escovopsis, which modifies both bacterial and behavioral defences such that colony collapse is unavoidable once Escovopsis infections escalate

Microbiomes of ant castes implicate new microbial roles in the fungus-growing ant Trachymyrmex septentrionalis

Fungus-growing ants employ several defenses against diseases, including disease-suppressing microbial biofilms on their integument and in fungal gardens. Here, we compare the phenology of microbiomes in natural nests of the temperate fungus-growing ant Trachymyrmex septentrionalis using culture-dependent isolations and culture-independent 16S-amplicon 454-sequencing. 454-sequencing revealed diverse actinobacteria associated with ants, including most prominently Solirubrobacter (12.2–30.9% of sequence reads), Pseudonocardia (3.5–42.0%), and Microlunatus (0.4–10.8%). Bacterial abundances remained relatively constant in monthly surveys throughout the annual active period (late winter to late summer), except Pseudonocardia abundance declined in females during the reproductive phase. Pseudonocardia species found on ants are phylogenetically different from those in gardens and soil, indicating ecological separation of these Pseudonocardia types. Because the pathogen Escovopsis is not known to infect gardens of T. septentrionalis, the ant-associated microbes do not seem to function in Escovopsis suppression, but could protect against ant diseases, help in nest sanitation, or serve unknown functions